Publications

expression profiles of dax1, dmrt1, and sox9 during temperature sex determination in gonads of the sea turtle lepidochelys olivacea.	sex determination is controlled either by genetic or environmental factors. in mammals sry initiates determination but no homologue of this gene exists in non-mammalian species. other genes of the mammalian sex-determining pathway have been identified in gonads of different vertebrates. sox9, dax1, and dmrt1 are expressed at the onset of gonadal development in birds and reptiles. in the sea turtle lepidochelys olivacea, a species with temperature sex determination (tsd), sox9 is expressed in und ...	2002	12409092
multiple paternity and female-biased mutation at a microsatellite locus in the olive ridley sea turtle (lepidochelys olivacea).	multiple paternity in the olive ridley sea turtle (lepidochelys olivacea) population nesting in suriname was demonstrated using two microsatellite loci, viz., ei8 and cm84. the large number of offspring sampled per clutch (70 on average, ranging from 15 to 103) and the number of alleles found at the two loci (18 and eight alleles, respectively) enabled unambiguous assessment of the occurrence of multiple paternity. in two out of 10 clutches analysed, the offspring had been sired by at least two ...	2002	12136412
timing of sox9 downregulation and female sex determination in gonads of the sea turtle lepidochelys olivacea.	the sry-related gene sox9 is involved in the differentiation of sertoli cells in male gonads of vertebrates with different kinds of sex determination. in the olive ridley lepidochelys olivacea, a species with temperature sex determination (tsd), the sox9 protein is expressed at stages 21-24 in medullary cells in gonads of embryos incubated at both male-(mpt) or female-promoting temperatures (fpt). however, at fpt the expression of sox9 protein decreases at stage 25 and disappears at stage 26, su ...	2001	11555857
temperature regulates sox9 expression in cultured gonads of lepidochelys olivacea, a species with temperature sex determination.	although sex determination starts in the gonads, this may not be the case for species with temperature sex determination (tsd). since temperature affects the whole embryo, extragonadal thermosensitive cells may produce factors that induce gonadal sex determination as a secondary event. to establish if gonads of a species with tsd respond directly to temperature, pairs of gonads were cultured, one at female-promoting temperature (fpt) and the contralateral at male-promoting temperature (mpt). his ...	2001	11150238
persistent infectivity of a disease-associated herpesvirus in green turtles after exposure to seawater.	herpesviruses are associated with several diseases of marine turtles including lung-eye-trachea disease (letd) and gray patch disease (gpd) of green turtles (chelonia mydas) and fibropapillomatosis (fp) of green, loggerhead (caretta caretta), and olive ridley turtles (lepidochelys olivacea). the stability of chelonian herpesviruses in the marine environment, which may influence transmission, has not been previously studied. in these experiments, letd-associated herpesvirus (letv) was used as a m ...	2000	11085447
differential expression of sox9 in gonads of the sea turtle lepidochelys olivacea at male- or female-promoting temperatures.	in mouse and chick embryos, the sox9 gene is down-regulated in genetic females whereas in genetic males it remains in the sertoli cells. we studied the distribution of sox9 protein in developing genital ridges of embryos of the sea turtle lepidochelys olivacea incubated at male- or female-promoting temperatures, using the antibody for detection. at stages 22-24, cells in medullary cords show sox9 positive nuclei, while coelomic epithelial cells appear negative. at stage 25 however, most medullar ...	1999	10531557
basal and stress-induced corticosterone levels in olive ridley sea turtles (lepidochelys olivacea) in relation to their mass nesting behavior.	adrenocortical responsiveness to turning stress was examined in wild, reproductively-active olive ridley sea turtles (lepidochelys olivacea) in relation to their mass nesting (arribada) behavior. we hypothesized that the high sensitivity threshold (hst) observed in ovipositing sea turtles is associated with a diminished sensitivity of the hypothalamo-pituitary-adrenal (hpa) axis to stressful stimuli in arribada females. we tested this hypothesis by determining whether arribada females exhibited ...	1999	10531552
acetylcholinesterase-positive innervation is present at undifferentiated stages of the sea turtle lepidochelis olivacea embryo gonads: implications for temperature-dependent sex determination.	in embryos of different reptile species, incubation temperature triggers a cascade of endocrine events that lead to gonad sex differentiation. the cellular and molecular mechanisms by which temperature sets in motion this process are still controversial. here, we begin evaluating the possible participation of the nervous system in temperature-dependent sex determination by showing the existence and origin of acetylcholinesterase (ache)-positive nerve fibers in undifferentiated gonads of the lepi ...	1999	10397397
calcium metabolism in olive ridley turtle eggs during embryonic development.	analyses of calcium, magnesium, sulphur, potassium and phosphorus content of the eggshell, yolk-albumen and embryos of olive ridley turtle, lepidochelys olivacea, have been carried out at various stages of embryonic development. calcium is the major inorganic constituent in the egg (shell and yolk-albumen) and embryos. other elements are present either in trace or in minute trace amounts. the egg contents (yolk and albumen) provide only 40% of the embryonic calcium requirement of the hatchling. ...	1998	9883572
sources of vibrio mimicus contamination of turtle eggs.	vibrio mimicus contamination of sand increased significantly during the arrival of the olive ridley sea turtles (lepidochelys olivacea) at ostional anidation beach, costa rica. statistical analysis supports that eggs are contaminated with v. mimicus by contact with the sand nest. v. mimicus was isolated from eggs of all nests tested, and ctxa+ strains were found in 31% of the nests, all of which were near the estuary.	1999	9872804
response of diencephalon but not the gonad to female-promoting temperature with elevated estradiol levels in the sea turtle lepidochelys olivacea.	although temperature sex determination is well known in several reptile species, the physiological mechanism underlying this process remains to be elucidated. in the current work, we analyzed the levels of testosterone (t) and estradiol (e2) in the gonads; two brain regions--telencephalon (te) and diencephalon/mesencephalon (di)--and the serum of developing embryos of the olive ridley lepidochelys olivacea incubated at male- or female-promoting temperatures. conversion of pregnenolone (p5) to t ...	1998	9493349
correlation among thermosensitive period, estradiol response, and gonad differentiation in the sea turtle lepidochelys olivacea.	reptile embryos with temperature sex determination have a thermosensitive period (tsp). the finding that exogenous estradiol (e2) overcomes the effect of male-promoting temperature led to the idea that temperature may regulate estrogen concentration in the gonad during tsp. since interspecific variations in tsp and in the effect of exogenous e2 exist, we undertook a study in the olive ridley lepidochelys olivacea. four parameters were correlated: the tsp (time dimension), the thermosensitive sta ...	1997	9268618
ultrastructure and characteristics of eggshells of the olive ridley turtle (lepidochelys olivacea) from gahirmatha, india.	the structure of a chelonian eggshell is of prime importance for the developing embryo. it acts as a protective covering as well as mediator in the exchange of heat and water. the fresh eggshell of the olive ridley (lepidochelys olivacea) turtle displays a variety of structural forms in their aragonite framework. its netted substrate, loose texture and poorly organised crystallites favour the easy exchange of air and water during its development. the shell consists mostly of calcium in carbonate ...	1996	9078397
vibrio mimicus diarrhea following ingestion of raw turtle eggs.	clinical and epidemiological characteristics of diarrhea associated with vibrio mimicus were identified in 33 hospitalized patients referred to the costa rican national diagnostic laboratory network between 1991 and 1994. the relevant symptoms presented by patients included abundant watery diarrhea, vomiting, and severe dehydration that required intravenous dhaka solution in 83% of patients but not fever. seroconversion against v. mimicus was demonstrated in four patients, from whom acute- and c ...	1996	8919774
histological and ultrastructural study of the lingual epithelium of the juvenile pacific ridley turtle, lepidochelys olivacea (chelonia, cheloniidae).	histological and ultrastructural studies ot the dorsal lingual epithelium of the juvenile pacific ridley turtle, lepidochelys olivacea, were performed by light and electron microscopy, and the results were compared to those of freshwater turtles in order to clarify the relationship between the histological and cellular differences of the lingual epithelium and the habitat of the turtles. the tongue of the juvenile pacific ridley turtle is triangular with a round apex when viewed from above, but ...	1996	8712372
a molecular phylogeny for marine turtles: trait mapping, rate assessment, and conservation relevance.	nucleotide sequences from the cytochrome b gene of mitochondrial dna were employed to resolve phylogenetic controversies and to assess molecular evolutionary rates in marine turtles (chelonioidea). findings of special relevance to conservation biology include discovery of a distant relationship between natator and other cheloniid species, the paraphyly of chelonia mydas with respect to chelonia agassizi, and genetic distinctiveness of lepidochelys kempi from lepidochelys olivacea. a longstanding ...	1993	8516304
monoclonal antibodies for the measurement of class-specific antibody responses in the green turtle, chelonia mydas.	monoclonal antibodies (mabs) were developed against the known immunoglobulin classes of the green turtle, chelonia mydas. plasma protein fractions enriched for 5.7s igy, 7s igy, and igm turtle immunoglobulins were used to immunize balb/c mice for hybridoma production and for hybridoma screening. fifteen hybridomas produced mabs with specificity for turtle immunoglobulins and for affinity purified dinitrophenol (dnp) specific turtle antibodies. three mabs specific for either turtle 5.7s igy heavy ...	1995	7502491
changes in lh and progesterone associated with the nesting cycle and ovulation in the olive ridley sea turtle, lepidochelys olivacea.		1982	6754526
increased levels of arginine vasotocin and neurophysin during nesting in sea turtles.	arginine vasotocin (avt) and neurophysin (np) levels were measured by radioimmunoassay in two species of sea turtle, the olive ridley, lepidochelys olivacea, and the loggerhead, caretta caretta, during the brief period of nesting and oviposition. in both species, avt was low in animals which were not reproductively active. avt was also low at the time animals emerged from the surf to nest, but increased significantly during oviposition and then declined as the animals returned to the water. np i ...	1989	2707582
light and scanning electron microscopic studies on the esophageal spines in the pacific ridley turtle, lepidochelys olivacea.	the peculairly specialized esophagus of the pacific ridley turtle, lepidochelys olivacea, was described by light and scanning electron microscopic studies. the esophagus is lined by a stratified squamous epithelium with remarkable keratinization, and its major part forms a number of large spines which have been called "pharyngeal teeth." the epithelium consists of three strate: stratum germinativum, stratum spinosum and stratum corneum. the surface of the spine is covered by a scaly keratin of p ...	1976	1275657