| influence of photoperiod and temperature on reproductive mode in the brine shrimp, artemia franciscana. | brine shrimp, artemia, exhibit two modes of reproduction: oviparity (diapause cyst production) and ovoviviparity (live larvae release). environmental conditions determining these developmental routes are poorly understood, so we investigated the effects of photoperiod and temperature on reproductive mode. nauplii of a. franciscana were hatched from cysts produced in the great salt lake, utah, and raised in 2% natural sea salt water under photoperiods of 24, 14, 12, or 10 h at 28 degrees or 20 de ... | 2004 | 15181648 |
| artemin is an rna-binding protein with high thermal stability and potential rna chaperone activity. | encysted embryos of the crustacean, artemia franciscana, are among the most stress-resistant of all multicellular eukaryotes, due in part to massive amounts of p26, a small heat shock protein, that acts as a molecular chaperone. these embryos contain equally large amounts of another protein called artemin, of previously unknown function, that we report on here. its thermal stability allows large-scale purification in about a day, using ammonium sulfate fractionation and incubation at 70 degrees ... | 2004 | 15047191 |
| differences in prey capture in grass shrimp, palaemonetes pugio, collected along an environmental impact gradient. | the waterways and associated salt marshes along the western border of staten island, new york (arthur kill) have long been under environmental duress. environmental threats include industrial and municipal discharges, oil spills, and possible leachate from landfills. these impacts are compounded due to the low flushing of this body of water. grass shrimp, palaemonetes pugio, inhabiting the arthur kill are, therefore, potentially at risk of exposure to metal and organic pollutants. successful pre ... | 2004 | 15025167 |
| molecular chaperones, stress resistance and development in artemia franciscana. | embryos of the brine shrimp, artemia franciscana, either develop directly into swimming larvae or are released from females as encysted gastrulae (cysts) which enter diapause, a reversible state of dormancy. metabolic activity in diapause cysts is very low and these embryos are remarkably resistant to physiological stresses. encysting embryos, but not those undergoing uninterrupted development, synthesize large amounts of two proteins, namely p26 and artemin. cloning and sequencing demonstrated ... | 2003 | 14986854 |
| a small heat shock/alpha-crystallin protein from encysted artemia embryos suppresses tubulin denaturation. | small heat shock/alpha-crystallin proteins function as molecular chaperones, protecting other proteins from irreversible denaturation by an energy-independent process. the brine shrimp, artemia franciscana, produces a small heat shock/alpha-crystallin protein termed p26, found in embryos undergoing encystment, diapause, and metabolic arrest. these embryos withstand long-term anoxia and other stresses normally expected to cause death, a property likely dependent on molecular chaperone activity. t ... | 2003 | 14627204 |
| posterior patterning genes and the identification of a unique body region in the brine shrimp artemia franciscana. | all arthropods share the same basic set of hox genes, although the expression of these genes differs among divergent groups. in the brine shrimp artemia franciscana, their expression is limited to the head, thoracic/trunk and genital segments, but is excluded from more posterior parts of the body which consist of six post-genital segments and the telson (bearing the anus). nothing is currently known about the genes that specify the identity of these posterior structures. we examine the expressio ... | 2003 | 14561635 |
| mitochondrial mrna stability and polyadenylation during anoxia-induced quiescence in the brine shrimp artemia franciscana. | polyadenylation of messenger rna is known to be an important mechanism for regulating mrna stability in a variety of systems, including bacteria, chloroplasts and plant mitochondria. by comparison, little is known about the role played by polyadenylation in animal mitochondrial gene expression. we have used embryos of the brine shrimp artemia franciscana to test hypotheses regarding message stability and polyadenylation under conditions simulating anoxia-induced quiescence. in response to anoxia ... | 2003 | 12966060 |
| regulation of promoter occupancy during activation of cryptobiotic embryos from the crustacean artemia franciscana. | artemia franciscana embryos can suspend their development and metabolism at the gastrula stage to enter a state of cryptobiosis, forming cysts. embryonic development and metabolism can be resumed under favorable environmental conditions to give rise to free-swimming larvae or nauplii. the mechanisms that mediate these processes are not completely known. here, we report our studies of the mechanisms that regulate transcriptional activation upon exiting cryptobiosis. regulatory regions of several ... | 2003 | 12654895 |
| chronic toxicity of arsenic to the great salt lake brine shrimp, artemia franciscana. | we determined the chronic toxicity of arsenic (sodium arsenate) to the great salt lake brine shrimp, artemia franciscana. chronic toxicity was determined by measuring the adverse effects of arsenic on brine shrimp growth, survival, and reproduction under intermittent flow-through conditions. the study commenced with <24-h-old nauplii, continued through reproduction of the parental generation, and ended after 28 days of exposure. the concentrations tested were 4, 8, 15, 31, and 56mg/l dissolved a ... | 2003 | 12550094 |
| transcriptional initiation under conditions of anoxia-induced quiescence in mitochondria from artemia franciscana embryos. | in response to anoxia, embryos of the brine shrimp artemia franciscana are able coordinately to downregulate metabolism to levels low enough to permit survival for several years at room temperature. in addition to dramatic decreases in free atp levels and heat production, intracellular ph drops from 7.8 to 6.3 overnight. use of isolated mitochondria to study transcriptional responses to anoxia offers several advantages: (1). the localized nature of transcript initiation, processing and degradati ... | 2003 | 12502778 |
| molecular characterization of artemin and ferritin from artemia franciscana. | embryos of the brine shrimp, artemia franciscana, exhibit remarkable resistance to physiological stress, which is temporally correlated with the presence of two proteins, one a small heat shock/alpha-crystallin protein termed p26 and the other called artemin, of unknown function. artemin was sequenced previously by edman degradation, and its relationship to ferritin, an iron storage protein, established. the isolation from an artemia expressed sequence tag library of artemin and ferritin cdnas e ... | 2003 | 12492484 |
| regiospecific distribution of fatty acids in triacylglycerols of artemia franciscana nauplii enriched with fatty acid ethyl esters. | this paper reports the positional distribution of fatty acids in triacylglycerols (tag) of artemia franciscana nauplii enriched with each of palmitic (16:0), oleic (18:1n-9), linoleic (18:2n-6), linolenic (18:3n-3), eicosapentaenoic (20:5n-3), and docosahexaenoic (22:6n-3) acid ethyl esters. tag extracted from the enriched and unenriched nauplii were subjected to regiospecific analysis to determine the fatty acid compositions of the sn-1(3) and sn-2 positions of tag. in the unenriched nauplii, 1 ... | 2002 | 12381381 |
| expression of the artemia trachealess gene in the salt gland and epipod. | the drosophila trachealess gene encodes a basic-helix-loop-helix-pas transcription factor that controls the formation of the trachea and salivary duct. an ortholog of trachealess was identified in the brine shrimp, artemia franciscana, and was shown to be highly conserved by sequence identity. expression of artemia trachealess was observed at two sites during development: the naupliar salt gland and the juvenile thoracic epipod. these two organs function at their respective times of development ... | 2008 | 12356264 |
| yolk platelets in artemia embryos: are they really storage sites of immature mitochondria? | we have used semi-quantitative polymerase chain reaction (pcr) technology to determine the mitochondrial dna (mtdna) content of yolk platelets isolated from embryos of the brine shrimp, artemia franciscana, and ultrastructural analysis of yolk platelet formation to determine whether these organelles contain mitochondria as reported previously. using six different isolation and purification protocols, we found one yolk platelet preparation to be devoid of mtdna, while four yolk platelet preparati ... | 2002 | 12031476 |
| [growth of artenia franciscana and a. persimilis (crustacea, anostraca) under controlled conditions]. | growth (length) was compared in a. franciscana populations from utah, united states of america, and yape, chile, and a. persimilis (population from salinas de hidalgo, argentina), cultured under controlled conditions (24 degrees c, seawater 35 g/l, fed with chaetoceros calcitrans). there were significant differences among all stages of a. franciscana (utah) and a. persimilis, whereas we found significant differences only in two stages of a. persimilis and a. franciscana (yape); both a. francisca ... | 2001 | 11935913 |
| bioaccumulation of chlorpyrifos through an experimental food chain: study of protein hsp70 as biomarker of sublethal stress in fish. | the accumulation and transfer of the organophosphorus pesticide chlorpyrifos has been studied in an experimental aquatic two-level food chain using two species of the crustacean artemia (a. franciscana and a. parthenogenetica) and the small fish aphanius iberus. artemia adults contaminated by exposure to the pesticide in water were used as live prey for aphanius, the next trophic level. during the experimental bioaccumulation phase, fish were fed chlorpyrifos-contaminated artemia pools with conc ... | 2002 | 11815815 |
| small heat shock protein p26 associates with nuclear lamins and hsp70 in nuclei and nuclear matrix fractions from stressed cells. | the small heat shock/alpha-crystallin protein p26 undergoes nuclear translocation in response to stress in encysted embryos of the brine shrimp artemia franciscana. about 50% of total p26 translocates to nuclei in embryos treated with heat shock or anoxia, and in embryo homogenates incubated at low ph. nuclear fractionation shows that the majority of nuclear p26 and a nuclear lamin are associated with the nuclear matrix fraction. to further explore the roles of p26 and other hsps in stabilizing ... | 2002 | 11813265 |
| international study on artemia. lxii. genomic relationships between artemia franciscana and a. persimilis, inferred from chromocentre numbers. | chromocentres, i.e. heavily stainable heterochromatic areas with highly repetitive dna (a 130-bp repeat in the order of 6 x 105 copies per haploid genome) observed in the resting nucleus, are a reliable taxonomic trait and a good marker for speciation in artemia. this chromosome marker was evaluated in populations of two new world sibling species: a. franciscana, from north, central and south america, and a. persimilis from argentina. artemia persimilis showed the characteristically low average ... | 2001 | 11703507 |
| influence of trehalose on the molecular chaperone activity of p26, a small heat shock/alpha-crystallin protein. | encysted embryos of the primitive crustacean artemia franciscana are among the most resistant of all multicellular eukaryotes to environmental stress, in part due to massive amounts of a small heat shock/alpha-crystallin protein (p26) that acts as a molecular chaperone. these embryos also contain very large amounts of the disaccharide trehalose, well known for its ability to protect macromolecules and membranes against damage due to water removal and temperature extremes. therefore, we looked fo ... | 2001 | 11599574 |
| nuclear p26, a small heat shock/alpha-crystallin protein, and its relationship to stress resistance in artemia franciscana embryos. | the role of the small heat shock/alpha-crystallin protein, p26, in transcription in artemia franciscana embryos was examined using isolated nuclei, containing either control or elevated levels of p26, in transcription run-on assays. heat shock or anoxia in vivo and acid ph in vitro were used to transfer p26 into nuclei. the results suggest that parameters other than, or in addition to, p26 are responsible for the reduced transcription rates observed and that decreases in phi are involved. in viv ... | 2001 | 11507116 |
| toxicity, bioaccumulation, and interactive effects of organotin, cadmium, and chromium on artemia franciscana. | the effects of three organotin compounds-trimethyltin chloride, dimethyltin dichloride, and dibutyltin diacetate-and two heavy metals-cadmium and hexavalent chromium-on artemia franciscana mortality are investigated in this study. of all the compounds tested in this work, trimethyltin chloride was, by far, the most toxic. the toxicity order for the five compounds was trimethyltin chloride > potassium dichromate > dimethyltin dichloride > dibutyltin diacetate > cadmium chloride. the big differenc ... | 2001 | 11386732 |
| isolation of a cdna encoding a putative sparc from the brine shrimp, artemia franciscana. | sparc (secreted protein, acidic, rich in cysteine) is an extracellular matrix-associated and anti-adhesive glycoprotein extensively studied in vertebrates. its presence among invertebrates has been reported in nematodes and flies. we cloned a cdna containing a complete open reading frame for sparc from the brine shrimp, artemia franciscana. the amino acid sequence identity between the artemia and the fly sparcs was 55%, whereas that of the artemia and the nematode proteins was 45%. artemia and v ... | 2001 | 11368900 |
| cytogenetic proof that the brine shrimp artemia franciscana (crustacea, branchiopoda) is found in argentina. | artemia brine shrimps are commercially important and they have been extensively studied. this branchiopod crustacean is extensively used in aquaculture and other commercial and applied practices. the genus also awakes an increasing interest worldwide as an experimental model in other basic areas of research such as evolution and cytogenetics. in the present work adult male meiosis and nauplii mitotic cells in two artemia populations from argentina (mar chiquita and las tunas, córdoba province) a ... | 2000 | 11338428 |
| intestinal uptake of lipovitellin from brine shrimp (artemia franciscana) by larval inland silversides (menidia beryllina) and striped bass (morone saxatilis). | intestinal uptake of lipovitellin (lv) from brine shrimp (artemia franciscana) in larval inland silversides (menidia beryllina) and striped bass (morone saxatilis) was described using immunocytochemistry. polyclonal antisera were raised against two subunits of lv (lv68 and lv190). when tested by immunocytochemistry, anti-lv68 showed cross-reactivity with some of the pancreatic cells especially in inland silversides. therefore anti-lv190 was used to localize immunoreactive lv. inland silversides ... | 1998 | 11253815 |
| diguanosine nucleotide metabolism and the survival of artemia embryos during years of continuous anoxia. | encysted embryos of the primitive crustacean, artemia franciscana, are remarkably resistant to a variety of harsh environmental conditions, including continuous anoxia for periods of years at physiological temperatures and water contents. previous study produced no evidence of an ongoing anoxic metabolism, suggesting that these embryos remained viable in spite of the lack of detectable free energy flow and biosynthesis. that seeming violation of a major axiom of cell biology and biochemistry pro ... | 2001 | 11248674 |
| long-term anoxia in encysted embryos of the crustacean, artemia franciscana: viability, ultrastructure, and stress proteins. | cells of encysted embryos of artemia franciscana, the brine shrimp, are among the most resistant of all animal cells to extremes of environmental stress. we focus here on their ability to survive continuous anoxia for periods of years, during which their metabolic rate is undetectable. we asked whether their impressive tolerance was reflected in changes at the ultrastructural level. the ultrastructure of encysted embryos previously experiencing 38 days and 3.3 years of anoxia was compared with t ... | 2000 | 10994789 |
| thermal resistance, developmental rate and heat shock proteins in artemia franciscana, from san francisco bay and southern vietnam. | cysts (encysted gastrula embryos) of artemia franciscana collected from salterns in san francisco bay, california, usa (sf) were inoculated into much warmer growth ponds in the mekong delta region of vietnam (v) in 1996. v adults arising directly from these cysts during 17 april to 15 may produced their own cysts, which were collected, processed and stored until shipped to the usa for study. adults grown in the laboratory from sf cysts (those used for the inoculation) were less resistant to high ... | 2000 | 10962067 |
| [phylogenetic study of artemia from china using rapd and aflp markers]. | we have applied the techniques of rapd (random amplified polymorphic dna) and aflp (amplified fragment length polymorphism) to the analysis of the relationships among artemia species and strains. rapd markers were successfully employed to detect diversity and genetic differentiation among four species of brine shrimp: a. franciscana, a. urmiana, a. sinica, and a. parthenogenetica. seventy, ten-base synthetic oligonucleotides were used to amplify a total of 458 distinct fragments. dna polymorphis ... | 2000 | 10887692 |
| the heat shock response of adult artemia franciscana. | | 2000 | 10880872 |
| beta-hydroxybutyrate in developing nauplii of brine shrimp (artemia franciscana k.) under feeding and non-feeding conditions. | body content of beta-hydroxybutyrate, and individual dry mass, carbon content, and survival rate, were studied in developing nauplii of the brine shrimp artemia franciscana k. from hatching to 96-97 h post hatching at 27 +/- 1 degrees c. the effect of two diets was studied in the experiment: super selco (ss) with a high lipid content; and protein selco (ps) with a high protein content. a starving group (s) was used as reference. the level of beta-hydroxybutyrate at hatching was 0.6 nmol.ind-1; i ... | 2000 | 10840642 |
| posttranslationally modified tubulins and microtubule organization in hemocytes of the brine shrimp, artemia franciscana. | crustaceans possess blood cells (hemocytes) that mediate organismal defense and are analogous to vertebrate leukocytes. in order to more fully characterize these types of cells, hemocytes of the branchiopod crustacean, artemia franciscana, were analyzed. the data indicate that artemia have one type of hemocyte, ranging in morphology from compact and spherical to flat and spreading when examined in vitro. electron microscopy revealed many cytoplasmic granules in the hemocytes and only a limited n ... | 2000 | 10814999 |
| crustacean (malacostracan) hox genes and the evolution of the arthropod trunk. | representatives of the insecta and the malacostraca (higher crustaceans) have highly derived body plans subdivided into several tagma, groups of segments united by a common function and/or morphology. the tagmatization of segments in the trunk, the part of the body between head and telson, in both lineages is thought to have evolved independently from ancestors with a distinct head but a homonomous, undifferentiated trunk. in the branchiopod crustacean, artemia franciscana, the trunk hox genes a ... | 2000 | 10804167 |
| characterization of atp-dependent proteolysis in embryos of the brine shrimp, artemia franciscana. | under anoxia, embryos of artemia franciscana enter a state of quiescence. during this time protein synthesis is depressed, and continued degradation of proteins could jeopardize the ability to recover from quiescence upon return to favorable conditions. in this study, we developed an assay for monitoring atp/ ubiquitin-dependent proteolysis in order to establish the presence of this degradation mechanism in a. franciscana embryos, and to describe some characteristics that may regulate its functi ... | 2000 | 10791572 |
| depression of nuclear transcription and extension of mrna half-life under anoxia in artemia franciscana embryos. | transcriptional activity, as assessed by nuclear run-on assays, was constant during 10 h of normoxic development for embryos of the brine shrimp artemia franciscana. exposure of embryos to only 4 h of anoxia resulted in a 79.3+/-1 % decrease in levels of in-vivo-initiated transcripts, and transcription was depressed by 88. 2+/-0.7 % compared with normoxic controls after 24 h of anoxia (means +/- s.e.m., n=3). initiation of transcription was fully restored after 1 h of normoxic recovery. artifici ... | 2000 | 10708633 |
| regulatory features of transcription in isolated mitochondria from artemia franciscana embryos. | optimal conditions were developed for an in organello transcriptional run-on assay using mitochondria isolated from artemia franciscana embryos to investigate potential regulatory features of rna synthesis under conditions of anoxia-induced quiescence. transcription is not dependent on oxidative phosphorylation for maximal activity when exogenous atp is available. bona fide transcription products, as assessed by hybridization with specific mitochondrial cdnas from a. franciscana, are produced in ... | 1999 | 10600903 |
| reexamination of hemocytes in brine shrimp (crustacea, branchiopoda). | in 1941, a single type of hemocyte was described in the blood of the brine shrimp artemia salina using light microscopy. this condition is unusual because most crustaceans examined using morphological, cytochemical, and functional methods have at least two types of hemoctyes. upon examining a. franciscana, we found a single type of disk-shaped hemocyte, with a centrally located nucleus and about 15 large (6 microm diameter) granules. the granules stain for the presence of acid phosphatase and re ... | 1999 | 10580266 |
| hypoxia accelerates the development of respiratory regulation in brine shrimp - but at a cost | the ability to regulate o(2) uptake during exposure to acutely declining o(2) tensions developed early (stage 6) in the brine shrimp artemia franciscana and co-occurred with the appearance of a functional heart and gills. culture under chronic hypoxia (p(o2)=10 kpa) resulted in this regulation being brought forward both in development (to stage 3) and in time (hypoxia stimulated early growth), but still before heart and gill formation took place. consequently, it was suggested that the hypoxia-r ... | 1999 | 10574741 |
| experimental studies of extinction dynamics | extinction of populations occurs naturally, but global extinction rates are accelerating, making understanding extinction a high priority for conservation. extinction in experimental populations of brine shrimp (artemia franciscana) was measured to assess hypothesized extinction processes. greater initial population size, greater maximum population size supported by the environment, and lower variation in environmental conditions reduced the likelihood of extinction, as hypothesized. however, in ... | 1999 | 10550058 |
| the synthesis of a small heat shock/alpha-crystallin protein in artemia and its relationship to stress tolerance during development. | fertilized oocytes of the brine shrimp artemia franciscana undergo either ovoviviparous or oviparous development, yielding free-swimming larvae (nauplii) or encysted gastrulae (cysts), respectively. encystment is followed by diapause, wherein metabolism is greatly reduced; the resulting cysts are very resistant to extreme stress, including desiccation and long-term anoxia. the synthesis of p26, a small heat shock/alpha-crystallin protein produced only in oviparously developing artemia, is shown ... | 1999 | 10068475 |
| formation of a covalent nepsilon2-guanylylhistidyl reaction intermediate by the gtp:gtp guanylyltransferase from the brine shrimp artemia. | the chemical nature of the enzyme-nucleotide phosphoramidate reaction intermediate employed by the unique gtp:gtp guanylyltransferase from yolk platelets of artemia franciscana cysts to synthesize diguanosine tetraphosphate (gp4g) has been investigated. labeling of the enzyme with [alpha-32p]gtp followed by isolation of the labeled phosphoamino acid by periodate treatment and alkaline hydrolysis and comparison of the product with phosphoamino acid standards by thin-layer and ion-exchange chromat ... | 1999 | 9882433 |
| cloning and sequencing of an alpha-tubulin cdna from artemia franciscana: evidence for translational regulation of alpha-tubulin synthesis. | the brine shrimp, artemia franciscana, exhibits a limited number of tubulin isotypes which change little during early postgastrula growth. in order to better understand the synthesis of alpha-tubulins during artemia development, a cdna termed alphaat1 was cloned and sequenced. alignment analyses revealed that the polypeptide encoded by alphaat1 is similar to alpha-tubulins from other species. hybridization of alphaat1 to restriction-digested dna on southern blots produced a simple banding patter ... | 1998 | 9805005 |
| identification of a mitochondrial rna polymerase in the crustacean artemia franciscana. | mitochondrial rna polymerase activity has been isolated from the crustacean artemia franciscana at two stages of development, dormant embryo and developing larva. the preparations were obtained from purified mitochondria and the polymerase activity was purified by heparin-sepharose chromatography. the presumed polymerase has a molecular mass of about 120 kda and a 7.4 s sedimentation coefficient. the biochemical characterization of the enzymatic reaction identified our rna polymerase preparation ... | 1998 | 9606962 |
| quiescence in artemia franciscana embryos: reversible arrest of metabolism and gene expression at low oxygen levels. | depression of the production and consumption of cellular energy appears to be a prerequisite for the survival of prolonged bouts of anoxia. a correlation exists between the degree of metabolic depression under anoxia and the duration of anoxia tolerance. in the case of brine shrimp (artemia franciscana) embryos, oxygen deprivation induces a reversible quiescent state that can be tolerated for several years with substantial survivorship. a global arrest of cytoplasmic translation accompanies the ... | 1998 | 9510534 |
| oxygen, phi and arrest of biosynthesis in brine shrimp embryos. | embryos of the brine shrimp artemia franciscana are able to withstand bouts of environmental anoxia for several years by entering a quiescent state, during which time metabolism is greatly depressed. within minutes of oxygen removal, intracellular ph (phi) drops at least 1.0 unit. this acidification has been strongly implicated in the arrest of both catabolic and anabolic processes in the cytoplasm. a global arrest of cytoplasmic translation accompanies the transition into anoxia or into aerobic ... | 1997 | 9429663 |
| mitochondrial transcription initiation in the crustacean artemia franciscana. | mitochondrial transcription has been studied in several vertebrate organisms, but so far no report on mitochondrial transcription initiation in invertebrates has been published. here we present an analysis of transcription initiation sites using in vivo-synthesized transcripts in the crustacean artemia franciscana. the mitochondrial genome of artemia has the same coding capacity as most animal mitochondrial genomes, and its overall organization is almost identical to that of drosophila. using in ... | 1997 | 9428705 |
| protein kinases in mitochondria of the invertebrate artemia franciscana. | the information concerning protein kinases in animal mitochondria is scarce and related only to mammals. no data are available for invertebrates. we demonstrate here the presence of casein kinase ii (ck ii) and camp-dependent protein kinase (pka) in the purified mitochondria of the crustacean artemia franciscana. whereas the mitochondrial ck ii showed the same characteristics of the cytosolic enzyme, mitochondrial pka had an apparent km for its substrate kemptide 1 order of magnitude lower than ... | 1997 | 9056227 |
| ontogenetic habitat selection by hadwenius pontoporiae (digenea: campulidae) in the intestine of franciscanas (cetacea). | the linear habitat selection of 4 sequential maturity stages (1, 2, 3, and 4) of the trematode hadwenius pontoporiae in the intestines of 26 south american dolphins pontoporia blanvillei was investigated. the franciscana is a suitable host for h. pontoporiae because all 26 hosts were infected, the infrapopulations being composed mostly of gravid (stage 4) worms. most trematodes were found in the first third of the intestine. the niches of the maturity stages decreased from stage 1 to 4. gravid w ... | 1997 | 9057690 |
| effect of anaerobiosis on cysteine protease regulation during the embryonic-larval transition in | hydrated encysted embryos of the brine shrimp artemia franciscana have the ability to withstand years in anaerobic sea water using metabolic strategies that enable them to inactivate all cell metabolic activities and then to resume development when placed in aerobic sea water. however, this unique characteristic of artemia franciscana embryos is lost during a very short period, at the embryonic­larval transition period of development, coincident with the appearance of prenauplius larvae. thu ... | 1997 | 9318685 |
| embryos of artemia franciscana survive four years of continuous anoxia: the case for complete metabolic rate depression | encysted gastrula embryos of the crustacean artemia franciscana have acquired an array of adaptations that enable them to survive a wide variety of environmental extremes.the present paper shows that at least 60 % survive 4 years of continuous anoxia at physiological temperatures (20­23 °c) when fully hydrated. although these embryos appear to carry on a metabolism during the first day of anoxia, no evidence for a continuing metabolism throughout the subsequent 4 years was obtained. duri ... | 1997 | 9318130 |
| profiles of nuclear and mitochondrial encoded mrnas in developing and quiescent embryos of artemia franciscana. | embryos of the brine shrimp artemia franciscana are able to withstand long bouts of environmental anoxia by entering a quiescent state during which metabolism is greatly depressed. recent evidence supports a global arrest of protein synthesis during quiescence. in this study we measured the amounts of mrna for a mitochondrial-encoded subunit of cytochrome c oxidase (cox i) and for nuclear-encoded actin during aerobic development, anaerobiosis, and aerobic acidosis (artificial quiescence imposed ... | 1996 | 8817476 |
| segmentation in the crustacean artemia: engrailed staining studied with an antibody raised against the artemia protein. | we have studied the process of post-embryonic segmentation in the anostracan crustacean artemia franciscana using a specific antibody raised against the engrailed protein of this organism. three cephalic segments are specified during embryonic development, before larval hatching, whilst trunk (thoracic) segmentation begins after the first stage free-swimming nauplius larva has emerged from the dormant cyst. thus, cephalic and trunk segmentation seem to be at least in part independent and superim ... | 1996 | 28306093 |
| tissue-specific expression of two artemia franciscana sarco/endoplasmic reticulum ca-atpase isoforms. | the sarco/endoplasmic reticulum ca-atpase (serca) gene from artemia franciscana is transcribed into two mrnas that code for two different enzyme isoforms. we investigated the tissue-specific expression of each mrna by in situ hybridization of larval tissue sections. one of the isoforms is expressed in the muscle fibers of the appendages. the other isoform is generally expressed throughout all tissues of the larvae. the tissue distribution of these two isoforms is very similar to the one describe ... | 1996 | 8601691 |
| acute depression of mitochondrial protein synthesis during anoxia: contributions of oxygen sensing, matrix acidification, and redox state. | mitochondrial protein synthesis is acutely depressed during anoxia-induced quiescence in embryos of artemia franciscana. oxygen deprivation is accompanied in vivo by a dramatic drop in extramitochondrial ph, and both of these alterations strongly inhibit protein synthesis in isolated mitochondria. here we show that the oxygen dependence is not explained simply by blockage of the electron transport chain or by the increased redox state. whereas oxygen deprivation substantially depressed protein s ... | 1996 | 8631750 |
| mitochondrial differentiation during the early development of the brine shrimp artemia franciscana. | during the early development of artemia there is an increase in mitochondrial enzyme activities of about one order of magnitude, whereas the activities of two cytoplasmic enzymes tested as controls remain unaltered. the mitochondrial enzyme activation correlates with (i) large changes in mitochondrial morphology, (ii) a 5-fold increase in the amount of the h+-atp synthase beta-subunit and (iii) a dramatic increase in the steady-state level of mitochondrial mrnas, whereas mitochondrial rrna conce ... | 1996 | 8670064 |
| transcriptional regulation during the activation and development of artemia franciscana encysted embryos. | | 1996 | 9087711 |
| oxygen and ph regulation of protein synthesis in mitochondria from artemia franciscana embryos. | to identify factors responsible for the down-regulation of mitochondrial biosynthetic processes during anoxia in encysted artemia franciscana embryos, the effects of oxygen limitation and ph on protein synthesis were investigated in isolated mitochondria. at the optimal ph of 7.5, exposure of mitochondria to anoxia decreases the protein synthesis rate by 79%. rates were suppressed by a further 10% at ph 6.8, the intracellular ph (phi) measured under anoxia in vivo. matrix ph, measured under iden ... | 1996 | 8546685 |
| effect of microgravity and hypergravity on embryo axis alignment during postencystment embryogenesis in artemia franciscana (anostraca). | cysts of brine shrimp attached with a liquid adhesive to 12-mm diameter glass coverslips in a syringe-type fluid processing apparatus were flown aboard the nasa space shuttle discovery, flight sts-60, from 3-11 february 1994, and were allowed to undergo postencystment embryogenesis and to hatch in microgravity. the shuttle flight and the ground-based control coverslips with attached cysts were parallel to the earth's surface during incubation in salt water. based on the position of the cyst shel ... | 1995 | 11539283 |
| potential role in development of the major cysteine protease in larvae of the brine shrimp artemia franciscana. | encysted embryos and larvae of the brine shrimp artemia franciscana contain a cysteine protease which represents over 90% of the protease activity in these organisms. we have used immunocytochemical methods to determine the localization and potential role of the cysteine protease in development of young larvae. in prenauplius larvae, there is intense staining for the protease on the basal side of the epidermal layer in the posterior region and diffuse staining for the protease throughout the emb ... | 1995 | 8581922 |
| tissue-specific alternative promoters regulate the expression of the two sarco/endoplasmic reticulum ca-atpase isoforms from artemia franciscana. | the sarco/endoplasmic reticulum ca-atpase gene from artemia franciscana is transcribed into two mrnas of 4.5 and 5.2 kb that code for protein isoforms differing at their carboxyl terminus. northern blot assays and anchored polymerase chain reaction (pcr) experiments have shown that these two mrnas also differ at the initial part of their 5' untranslated region. the 5.2-kb mrna-specific 5' untranslated region is present as an independent exon whose transcription is regulated by a promoter differe ... | 1995 | 7546295 |
| hox genes and the diversification of insect and crustacean body plans. | crustaceans and insects share a common origin of segmentation, but the specialization of trunk segments appears to have arisen independently in insects and various crustacean subgroups. such macroevolutionary changes in body architecture may be investigated by comparative studies of conserved genetic markers. the hox genes are well suited for this purpose, as they determine positional identity along the body axis in a wide range of animals. here we examine the expression of four hox genes in the ... | 1995 | 7630416 |
| phylogenetic study of bisexual artemia using random amplified polymorphic dna. | study of polymorphisms in the eukaryotic genome is an important way to discover the evolutionary relationships between species. artemia (crustacea, anostraca) offers a very interesting model for evolutionary studies. in fact the genus, distributed all over the world in hundreds of known biotopes, comprises both bisexual sibling species and parthenogenetic populations easily available from the artemia reference center of ghent. in spite of great interest in it and its extensive use in aquaculture ... | 1995 | 7666444 |
| nuclear-cytoplasmic translocations of protein p26 during aerobic-anoxic transitions in embryos of artemia franciscana. | embryos of the crustacean artemia franciscana survive continuous anoxia for periods of years, during which their metabolism comes to a reversible stand-still. a question of some interest concerns the maintenance of cellular integrity in the absence of biosynthesis and an ongoing energy metabolism. the present paper continues previous work on an abundant protein (p26) that undergoes extensive intracellular translocation during aerobic-anoxic transitions, exhibits several characteristics of stress ... | 1995 | 7628526 |
| in situ hybridization analyses of na, k-atpase alpha-subunit expression during early larval development of artemia franciscana. | the spatial pattern of expression of the mrna encoded by the na,k-atpase alpha-subunit cdna clone paratna136 was determined by in situ hybridization of first, second, and third instar artemia franciscana larvae. this mrna was expressed at high levels in the salt gland, the antennal gland, and the end of the midgut, which are the three main osmoregulatory organs in artemia at these stages of development. the pattern of expression was similar at the three stages of development analyzed, although t ... | 1995 | 7897181 |
| reactivation of ubiquitination in artemia franciscana embryos during recovery from anoxia-induced quiescence | encysted gastrulae of artemia franciscana are known to enter a reversible state of quiescence promoted by anoxia, during which the half-life of cytochrome oxidase is prolonged up to 77-fold. this observation suggests that proteolytic pathways within mitochondria are inhibited, and indeed the suppression of the initial step in ubiquitin-mediated proteolysis under anoxia has been reported. given that active embryos require efficient degradation of macromolecules, we investigated the reactivation o ... | 1995 | 9319173 |
| ontogeny of cardiac function in the brine shrimp artemia franciscana kellogg 1906 (branchiopoda: anostraca). | in newly hatched brine shrimp (artemia franciscana) cardiac organogenesis and function could only take place with the onset of segmentation. consequently differences in age, body size and temperature (in the range 22-34 degrees c) affected the ontogeny of cardiac activity only indirectly, through their influence on developmental stage. once present the frequency of cardiac activity (heart beat) increased with increasing body size and concomitant differentiation of cardiac tissue. at least initia ... | 1994 | 7798869 |
| identification of an artemia franciscana retropseudogene containing part of the last exons of the sarco/endoplasmic reticulum ca-atpase-encoding serca gene. | a genomic clone has been isolated which contains sequences highly homologous to part of exon 14 and exons 15, 16 and 17 of the artemia franciscana sarco-endoplasmic reticulum ca-atpase(serca)-encoding gene, but none of the introns. the homologous region extends to the 3' end of the mrna, although the poly(a) tail is not present. the structure of this clone suggests that it represents a 5'-end-truncated retropseudogene (r psi). | 1994 | 7959022 |
| the complete mitochondrial dna sequence of the crustacean artemia franciscana. | the complete mitochondrial dna (mtdna) sequence of the brine shrimp artemia franciscana has been determined. it extends the present knowledge of mitochondrial genomes to the crustacean class and supplies molecular markers for future comparative studies in this large branch of the arthropod phylum. artemia mtdna is 15,822 nucleotides long, and when compared with its drosophila counterpart, it shows very few gene rearrangements, merely affecting two trnas placed 3' downstream of the nd 2 gene. in ... | 1994 | 7966370 |
| acute blockage of the ubiquitin-mediated proteolytic pathway during invertebrate quiescence. | many organisms withstand adverse environmental conditions by entering a reversible state of quiescence that may last for months or years. in this report we provide evidence that the reduction in adenylate energy status and the associated intracellular acidosis occurring during anoxia-induced quiescence combine to inhibit, directly or indirectly, the initial step in the ubiquitin-mediated proteolytic pathway in embryos of the brine shrimp artemia franciscana. the levels of ubiquitin-conjugated pr ... | 1994 | 7943430 |
| global arrest of translation during invertebrate quiescence. | comparing the translational capacities of cell-free systems from aerobically developing embryos of the brine shrimp artemia franciscana vs. quiescent embryos has revealed a global arrest of protein synthesis. incorporation rates of [3h]leucine by lysates from 4-h anoxic embryos were 8% of those from aerobic (control) embryos, when assayed at the respective ph values measured for each treatment in vivo. exposure of embryos to 4 h of aerobic acidosis (elevated co2 in the presence of oxygen) suppre ... | 1994 | 8078909 |
| topoisomerase i action on the heterochromatic dna from the brine shrimp artemia franciscana: studies in vivo and in vitro. | the genomes of higher eukaryotes contain various amounts of tandem repeated dna sequences (satellite dna) typically located in the constitutive heterochromatin, the most highly condensed region of interphase chromosomes. we have previously demonstrated that an alui dna family of repeats is the major component of constitutive heterochromatin in the brine shrimp artemia franciscana. the analysis of cloned heterochromatic fragments revealed that this repetitive dna shows a stable curvature conferri ... | 1994 | 8192650 |
| extensive intracellular translocations of a major protein accompany anoxia in embryos of artemia franciscana. | cells of encysted gastrula embryos of the crustacean artemia franciscana exhibit extraordinary stability during prolonged anoxia. we find that they contain an abundant protein (referred to as "26-kda protein") that undergoes translocation to the nucleus during anoxia. the reverse translocation rapidly occurs when anoxic embryos are returned to aerobic conditions. a similar translocation appears to take place in embryos exposed to 42 degrees c aerobic heat shock and prolonged exposure to low temp ... | 1994 | 8174644 |
| gene expression after resumption of development of artemia franciscana cryptobiotic embryos. | the steady-state levels of six different mrnas have been studied during artemia franciscana development. some of these mrnas are present in the cryptobiotic cyst, like those coding for cytoplasmic actins, sarcoplasmic/endoplasmic reticulum ca(2+)-atpase, and the na+, k(+)-atpase alpha-subunit isoform coded by the clone paratna136. the expression of these mrnas is markedly induced during cyst development. a small increase in mrna levels can be observed for some genes at very early stages of devel ... | 2010 | 7818853 |
| embryogenesis, hatching and larval development of artemia during orbital spaceflight. | developmental biology studies, using gastrula-arrested cysts of the brine shrimp artemia franciscana, were conducted during two flights of the space shuttle atlantis (missions sts-37 and sts-43) in 1991. dehydrated cysts were activated, on orbit, by addition of salt water to the cysts, and then development was terminated by the addition of fixative. development took place in 5 ml syringes, connected by tubing to activation syringes, containing salt water, and termination syringes, containing fix ... | 1994 | 11537922 |
| structure and expression of a polyubiquitin gene from the crustacean artemia. | we have characterized two polyubiquitin genes from the crustacean artemia franciscana. one of them, ubi1, has nine ubiquitin units and an intron of a minimum size of 3.5 kb that ends 7 bp before the initiator atg. the 5' end of the transcript from this gene has been identified by anchored pcr. the existence of the other gene (ubi2) was inferred from several cdna clones that differ from ubi1 in the c-terminal extension and in the 3' untranslated region as well as in the nucleotide sequence of the ... | 1994 | 7841785 |
| genomic organization and developmental pattern of expression of the engrailed gene from the brine shrimp artemia. | we report the isolation and characterization of an engrailed gene in the crustacean artemia franciscana. the artemia gene spans a genomic region of 15 kilobases and the coding sequence is interrupted by two introns. it appears to be the only gene of the engrailed family present in the artemia genome. the predicted engrailed-like protein is 349 amino acids long and contains several domains including the homeodomain, well conserved when compared to other proteins of the engrailed family. based on ... | 1993 | 7903633 |
| similar alternative splicing events generate two sarcoplasmic or endoplasmic reticulum ca-atpase isoforms in the crustacean artemia franciscana and in vertebrates. | a second isoform of the artemia franciscana sarcoplasmic or endoplasmic reticulum ca-atpase has been identified through the isolation of cdna clones. this isoform differs from the previously identified one only at the c-terminal end of the protein. the last 6 amino acids of the former isoform change to 30 hydrophobic amino acids in the newly identified isoform that have the potentiality of being an additional transmembrane domain. the two a. franciscana isoforms are highly homologous to the two ... | 1993 | 8314776 |
| hom/hox genes of artemia: implications for the origin of insect and crustacean body plans. | insects and crustaceans are generally assumed to derive from a segmented common ancestor that had a distinct head but uniform, undifferentiated trunk segments. the subdivision of the body into functionally distinct regions (e.g. thorax and abdomen) is thought to have evolved independently in these two lineages. in insects, the differences between segments in the trunk are controlled by the antennapedia-like genes of the homeotic gene clusters. study of these genes in crustaceans should provide a ... | 1993 | 15335797 |
| extension of enzyme half-life during quiescence in artemia embryos. | encysted gastrulae of artemia franciscana are known to enter a reversible state of quiescence in which biosynthetic and catabolic pathways are markedly suppressed. given that these embryos can survive months of anoxia, we investigated their ability to extend the half-life of cytochrome-c oxidase (cox), a key metabolic enzyme, during anoxia. we calculate that the half-life of cox is extended to 101 days under anoxia, an estimated 77-fold increase compared with aerobic values. during conditions of ... | 1993 | 8381619 |
| nucleotide variation and molecular structure of the heterochromatic repetitive alui dna in the brine shrimp artemia franciscana. | it has been suggested that dna bending could play a role in the regulation of gene expression, chromosome segregation, specific recombination and/or dna packaging. we have previously demonstrated that an alui dna family of repeats is the major component of constitutive heterochromatin in the brine shrimp a. franciscana. by the analysis of cloned oligomeric (monomer to hexamer) heterochromatic fragments we verified that the repetitive alui dna shows a stable curvature that determines a solenoidal ... | 1992 | 1474602 |
| aerobic heat shock activates trehalose synthesis in embryos of artemia franciscana. | encysted embryos (cysts) of the brine shrimp, artemia franciscana, contain large amounts of trehalose which they use as a major substrate for energy metabolism and biosynthesis for development under aerobic conditions at 25 degrees c. when cysts are placed at 42 degrees c (heat shock) these pathways stop, and the cysts re-synthesize the trehalose that was utilized during the previous incubation at 25 degrees c. glycogen and glycerol, produced from trehalose at 25 degrees c, appear to be substrat ... | 1992 | 1592115 |
| comparison of messenger rna pools in active and dormant artemia franciscana embryos: evidence for translational control. | in response to environmental anoxia, embryos of the brine shrimp artemia franciscana enter a dormant state during which energy metabolism and development are arrested. the intracellular acidification that correlates with this transition into anaerobic dormancy has been linked to the inhibition of protein synthesis in quiescent embryos. in this study, we have addressed the level of control at which a mechanism mediated by intracellular ph might operate to arrest protein synthesis. two independent ... | 1992 | 1349912 |
| purification and characterization of a proteolytic active fragment of dna topoisomerase i from the brine shrimp artemia franciscana (crustacea anostraca). | the atp-independent type i topoisomerase from the crustacean artemia franciscana was purified to near-homogeneity. its activity was measured by an assay that uses the formation of an enzyme-cleaved dna complex in the presence of the specific inhibitor camptothecin. the purification procedure is reported. purified topoisomerase is a single-subunit enzyme with a molecular mass of 63 kda. immunoblot performed on the different steps of purification shows that the purified 63 kda peptide is a proteol ... | 1992 | 1311554 |
| food-web modification by an invertebrate predator in the great salt lake (usa). | during unusually wet years the salinity of the great salt lake (utah) decreased from above 100 g/l to 50 g/l. this allowed the predaceous insect trichocorixa verticalis to invade the pelagic region of the lake and reach a mean summer density of 52/m(3). concurrent changes in the pelagic ecosystem were: a decrease in the dry biomass of the previously dominant filter-feeding brine shrimp artemia franciscana from 720 to 2 mg/m(3), the invasion of three other zooplankton taxa, a 10 × decrease in com ... | 1992 | 28312870 |
| liquid chromatographic determination of efficacy of incorporation of trimethoprim and sulfamethoxazole in brine shrimp (artemia spp.) used for prophylactic chemotherapy of fish. | the brine shrimp artemia, an excellent live food source in aquaculture, has been studied as a carrier to deliver selected chemotherapeutic agents to fish for prophylactic treatment of infectious diseases. to monitor the efficiency of incorporation of trimethoprim and sulfamethoxazole in artemia franciscana, a sensitive and specific analytical method was developed. it is based on homogenization of artemia nauplii in methanol, extraction of lipids with hexane, solid-phase cleanup on c18 cartridges ... | 1991 | 1810182 |
| a binding protein (p82 protein) recognizes specifically the curved heterochromatic dna in artemia franciscana. | dna bending has been suggested to play a role in the regulation of gene expression, initiation of dna replication, site specific recombination and dna packaging. in artemia franciscana (phillopoda anostraca) cells we have revealed that an alui dna family of repeats, 113-bp in length, is the major component of the constitutive heterochromatin found in the species. by analysis of cloned oligomeric (monomer to hexamer) heterochromatic fragments and electrophoretic experiments we verified that the r ... | 1990 | 2258053 |
| arrest of cytochrome-c oxidase synthesis coordinated with catabolic arrest in dormant artemia embryos. | we have examined cytochrome-c oxidase (cox) biosynthesis in brine shrimp (artemia franciscana) embryos during preemergence development (ped), as well as its inhibition under anaerobic dormancy, to determine whether transitions in intracellular ph (phi) have a regulatory influence on anabolic processes. under control aerobic conditions (embryo phi greater than or equal to 7.9), incorporation of radiolabeled amino acids shows that substantial biosynthesis of cox occurs during 12 h of ped (500% inc ... | 1990 | 2159729 |
| heat dissipation during long-term anoxia in artemia franciscana embryos: identification and fate of metabolic fuels. | microcalorimetric measurements of brine shrimp embryos during 6 days of anoxia indicated that heat dissipation was rapidly suppressed to 2.7% of control (aerobic) values over the first 9 h. energy flow continued to decline slowly to 31 microw.g dry mass-1 (0.4% of control) during the subsequent 5.5 days. within 2 h after returning anoxic embryos to aerobic conditions, heat dissipation rose to 77% of control rates. the calorimetric/respirometric (cr) ratio across this 2-h recovery period increase ... | 1990 | 2292613 |
| sequence-directed curvature of repetitive alui dna in constitutive heterochromatin of artemia franciscana. | an alu i family of repeated dna sequence 113 bp in length was found to be the major component of the heterochromatin in artemia franciscana. on the basis of the analysis of cloned oligomeric (monomer to examer) heterchromatic fragments we predicted that the sequence could produce a stable curvature in chromosomal dna. this prediction was confirmed by polyacrylamide gel electrophoresis analysis and by electron microscope observations. the anomalous mobility of these fragments is reversed when the ... | 1989 | 2813062 |
| cell-specific endopolyploidy in developing artemia. | cells in developing artemia franciscana sfb demonstrated tissue-specific differences in dna content, as determined by fluorescence intensity of bisbenzimide-stained nuclei and by nuclear area. the general epidermis comprised proliferating diploid (2c) cells. the setal cells had 4c-8c dna content and did not divide during the first two instars. salt gland cells were polyploid (>8c) and also did not undergo mitosis. neural cells in the brain were diploid and were replicating. cells in the thorax r ... | 1988 | 28305474 |
| control of colonial hydroid macrofouling by free-field ultrasonic radiation. | free-field ultrasonic radiation inhibited the feeding of the macrofouling hydroid garveia franciscana by causing tentacle contraction at the sonic degasification threshold. within the frequency range of 250 to 2000 kilohertz, the threshold sound intensity (sonic degasification threshold) that caused tentacle contraction was directly proportional to frequency, with the minimum observed being 0.6 watt per square centimeter at 250 kilohertz. a pulse length of 0.2 second and interpulse period of 102 ... | 1984 | 17746053 |
| the axial musculature of pontoporia blainvillei, with comments on the organization of this system and its effect on fluke-stroke dynamics in the cetacea. | the axial muscular system of pontoporia blainvillei is described and compared with published reports of this system in other cetaceans. a comprehensive system for classification of axial muscles is presented, based on the studies of slijper. a discrete obliquus capitis inferior is described for the first time in cetacea, and it is suggested that its absence in previous descriptions may have been due partly to dissection error. the major axial muscle-masses are organized in a similar way in most ... | 1980 | 7405862 |
| identification of 4,6-o-(1-carboxyethylidene)-d-galactose by combined gas chromatography mass spectrometry. | combined gas chromatography mass spectrometry was used to separate and identify a carrageenan component suspected of being the acid ketal 4,6-o-(1-carboxyethylidene)-d-galactose. the mass spectral fragmentation pattern is presented as evidence of the presence of this component in the carrageenan from petrocelis middendorfii (p. franciscana). | 1978 | 747739 |
| myology of the shoulder of pontoporia blainvillei, including a review of the literature on shoulder morphology in the cetacea. | the purpose of this paper is to describe in detail the shoulder myology of the la plata river dolphin, pontoporia blainvillei, and to review the literature on cetacean shoulder myology. three fetal and one adult animal were used for the collection of morphological information. pontoporia is less specialized in its shoulder anatomy that most delphinid cetaceans, and shares several characteristics with some mysticetes. the omohyoid and anterior serratus anterior muscles are found in both pontopori ... | 1978 | 677058 |
| lungs of franciscana (pontoporia blainvillei), with special references to their external aspects, weights and bronchial ramifications. | | 1977 | 859712 |
| the tongue of franciscana (la plata dolphin), pontoporia blainvillei. | | 1976 | 995350 |
| extrahepatic bile-passage of franciscana (la plata dolphin), pontoporia blainvillei. | | 1976 | 995349 |
| the liver of franciscana (la plata dolphin), pontoporia blainvillei. | | 1976 | 1272551 |
| some notes on the pancreas of franciscana (la plata dolphin), pontoporia blainvillei. | | 1975 | 1161261 |
| digestive tract of la plata dolphin, pontoporia blainvillei. ii. small and large intestines. | | 1975 | 1161260 |
| gene duplication and fixed heterozygosity for alcohol dehydrogenase in the diploid plant clarkia franciscana. | all individuals of the diploid plant clarkia franciscana, an annual species native to california, have duplicated genes for the dimeric enzyme alcohol dehydrogenase. since each gene specifies a polypeptide with a distinct charge, the species has a fixed heterozygous phenotype consisting of three isozyme variants. the enzyme is coded by a single gene in closely related species. clarkia franciscana is highly self-pollinated and monomorphic at all but one of its loci that have been examined. conseq ... | 1974 | 4525465 |