Publications

influence of temperature on the hygropreference of the collembolan, cryptopygus antarcticus, and the mite, alaskozetes antarcticus from the maritime antarctic.	the hygropreference of adult cryptopygus antarcticus and alaskozetes antarcticus was investigated over 2 h at 5, 10 and 20 degrees c, along humidity gradients (9-98% rh) established by means of different salt solutions. two chamber arrangements were employed, linear and grid, to determine any influence of thigmotactic behaviour on distribution within the rh gradient. the humidity preference of both species varied with temperature. at 5 and 10 degrees c, c. antarcticus distributed homogeneously s ...	2001	11033163
experimental studies of ice nucleation in an antarctic springtail (collembola, isotomidae).	ice nucleation was studied in field-fresh and acclimated (4 degrees c without food for 11-20 days) samples of the springtail cryptopygus antarcticus willem (collembola, isotomidae) at rothera research station, adelaide island on the antarctic peninsula. ice nucleator activity (ina) was measured by a freezing droplet technique in addition to supercooling point (scp) profiles and polyol, sugar, and water contents. field and acclimated samples showed bimodal scp distributions with a distinct high g ...	2001	11578116
refining the risk of freezing mortality for antarctic terrestrial microarthropods.	in studies of three common, freezing susceptible, antarctic microarthropods, the springtail cryptopygus antarcticus and the mites alaskozetes antarcticus and halozetes belgicae, we report (i) the consequences on cold tolerance of cooling in contact with water, and (ii) the risk of freezing when held at temperatures above the typical freezing point (measured using standard techniques) for up to 12 h. the springtail showed no change in scp distribution when in contact with freezing water while, in ...	2002	12148025
rapid cold hardening: a gut feeling.	this study examined the rate of cold hardening of a field population of antarctic springtails and the effect of eating food with particular levels of ice nucleating activity on the animal's whole body freezing point. the scps of samples of c. 20, freshly collected, cryptopygus antarcticus were measured hourly over a 32 hour collection period using differential scanning calorimetry and related to habitat temperature. the mean scp of the springtails increased from -24 to -10 degree c during which ...	2002	12148036
desiccation stress at sub-zero temperatures in polar terrestrial arthropods.	cold tolerant polar terrestrial arthropods have evolved a range of survival strategies which enable them to survive the most extreme environmental conditions (cold and drought) they are likely to encounter. some species are classified as being freeze tolerant but the majority of those found in the antarctic survive sub-zero temperatures by avoiding freezing by supercooling. for many arthropods, not just polar species, survival of desiccating conditions is equally important to survival of low tem ...	2003	12769994
acclimation effects on thermal tolerances of springtails from sub-antarctic marion island: indigenous and invasive species.	collembola are abundant and functionally significant arthropods in sub-antarctic terrestrial ecosystems, and their importance has increased as a consequence of the many invasive alien species that have been introduced to the region. it has also been predicted that current and future climate change will favour alien over indigenous species as a consequence of more favourable responses to warming in the former. it is therefore surprising that little is known about the environmental physiology of s ...	2007	17222862
recrystallisation temperature (trc) in an antarctic springtail.	cryobiologists have traditionally assumed that the temperature of crystallisation (tc) or supercooling point (scp) of a chill-tolerant insect is not a stochastic event, i.e. that it is a biologically meaningful indicator of phenotypic characteristics, be they exogenous influences (e.g. acclimation/acclimatization) or endogenous factors (e.g. life history stage, moult state). recent work by wilson et al. (11) has suggested that scps--at least in non-biological samples--are more stochastic than pr ...	2006	17256067
molecular cloning and characterization of a novel cold-active beta-1,4-d-mannanase from the antarctic springtail, cryptopygus antarcticus.	a cdna encoding a beta-1,4-d-mannanase (caman) was identified among the expressed sequence tags (ests) of the antarctic springtail, cryptopygus antarcticus. the open reading frame consisted of 1149 bp encoding 382 amino acids with a putative signal peptide. amino acid sequence comparison with other mannanases indicated that caman likely belongs to subfamily 10 of the glycoside hydrolase family 5, together with mollusc beta-mannanases. caman shows typical features of a cold-active enzyme: it has ...	2008	18579426
the complete mitochondrial genome of the antarctic springtail cryptopygus antarcticus (hexapoda: collembola).	mitogenomics data, i.e. complete mitochondrial genome sequences, are popular molecular markers used for phylogenetic, phylogeographic and ecological studies in different animal lineages. their comparative analysis has been used to shed light on the evolutionary history of given taxa and on the molecular processes that regulate the evolution of the mitochondrial genome. a considerable literature is available in the fields of invertebrate biochemical and ecophysiological adaptation to extreme envi ...	2008	18593463
the significance of the moult cycle to cold tolerance in the antarctic collembolan cryptopygus antarcticus.	research into the ecophysiology of arthropod cold tolerance has largely focussed on those parts of the year and/or the life cycle in which cold stress is most likely to be experienced, resulting in an emphasis on studies of the preparation for and survival in the overwintering state. however, the non-feeding stage of the moult cycle also gives rise to a period of increased cold hardiness in some microarthropods and, as a consequence, a proportion of the field population is cold tolerant even dur ...	2008	18662695
cold hardening processes in the antarctic springtail, cryptopygus antarcticus: clues from a microarray.	the physiology of the antarctic microarthropod, cryptopygus antarcticus, has been well studied, particularly with regard to its ability to withstand low winter temperatures. however, the molecular mechanisms underlying this phenomenon are still poorly understood. 1180 sequences (expressed sequence tags or ests) were generated and analysed, from populations of c. antarcticus. this represents the first publicly available sequence data for this species. a sub-set (672 clones) were used to generate ...	2008	18703067
desiccation tolerance and drought acclimation in the antarctic collembolan cryptopygus antarcticus.	the availability of water is recognized as the most important determinant of the distribution and activity of terrestrial organisms within the maritime antarctic. within this environment, arthropods may be challenged by drought stress during both the austral summer, due to increased temperature, wind, insolation, and extended periods of reduced precipitation, and the winter, as a result of vapor pressure gradients between the surrounding icy environment and the body fluids. the purpose of the pr ...	2008	18761345
gene expression associated with changes in cold tolerance levels of the antarctic springtail, cryptopygus antarcticus.	the ability of the antarctic microarthropod cryptopygus antarcticus (collembola, isotomidae) to survive low temperatures has been well studied at the physiological level, with recent investigations indicating the importance of the moulting process in conferring this ability. this study investigated gene expression in groups of c. antarcticus that have distinct differences in their ability to survive low temperatures. a microarray containing c. 5400 c. antarcticus expressed sequence tags was used ...	2010	20002214
molecular and biochemical characterizations of a novel arthropod endo-beta-1,3-glucanase from the antarctic springtail, cryptopygus antarcticus, horizontally acquired from bacteria.	collembolan species have been known to have beta-1,3-glucanase activity and yet the genes coding such enzymes have not been demonstrated. we report here a novel arthropod endo-beta-1,3-glucanase gene calam from the antarctic springtail, cryptopygus antarcticus. the open reading frame consists of 813bp encoding 270 amino acids with a putative signal peptide and a typical motif of glycosyl hydrolase family 16 (ghf16), e-i-d-i-t-e. the recombinant protein expressed in e. coli shows the hydrolytic a ...	2010	20079869
testing the effect of metabolic rate on dna variability at the intra-specific level.	we tested the metabolic rate hypothesis (whereby rates of mtdna evolution are postulated to be mediated primarily by mutagenic by-products of respiration) by examining whether mass-specific metabolic rate was correlated with root-to-tip distance on a set of mtdna trees for the springtail cryptopygus antarcticus travei from sub-antarctic marion island.using bayesian analyses and a novel application of the comparative phylogenetic method, we did not find significant evidence that contemporary meta ...	2010	20300626
biogeography of circum-antarctic springtails.	we examine the effects of isolation over both ancient and contemporary timescales on evolutionary diversification and speciation patterns of springtail species in circum-antarctica, with special focus on members of the genus cryptopygus (collembola, isotomidae). we employ phylogenetic analysis of mitochondrial dna (cox1), and ribosomal dna (18s and 28s) genes in the programmes mrbayes and raxml. our aims are twofold: (1) we evaluate existing taxonomy in light of previous work which found dubious ...	2010	20558307
the effect of acclimation temperature on thermal activity thresholds in polar terrestrial invertebrates.	in the maritime antarctic and high arctic, soil microhabitat temperatures throughout the year typically range between -10 and +5 °c. however, on occasion, they can exceed 20 °c, and these instances are likely to increase and intensify as a result of climate warming. remaining active under both cool and warm conditions is therefore important for polar terrestrial invertebrates if they are to forage, reproduce and maximise their fitness. in the current study, lower and upper thermal activity thres ...	2013	23973412
expression at 279 k, purification, crystallization and preliminary x-ray crystallographic analysis of a novel cold-active β-1,4-d-mannanase from the antarctic springtail cryptopygus antarcticus.	the caman gene product from cryptopygus antarcticus, which belongs to the glycoside hydrolase family 5 type β-1,4-d-mannanases, has been crystallized using a precipitant solution consisting of 0.1 m tris-hcl ph 8.5, 25%(w/v) polyethylene glycol 3350 by the microbatch crystallization method at 295 k. the caman protein crystal belonged to space group p212121, with unit-cell parameters a = 73.40, b = 83.81, c = 163.55 å. assuming the presence of two molecules in the asymmetric unit, the solvent con ...	2013	23989150
characterization of cryptopygus antarcticus endo-β-1,4-glucanase from bombyx mori expression systems.	endo-β-1,4-glucanase (cacel) from antarctic springtail, cryptopygus antarcticus, a cellulase with high activity at low temperature, shows potential industrial use. to obtain sufficient active cellulase for characterization, cacel gene was expressed in bombyx mori-baculovirus expression systems. recombinant cacel (rcacel) has been expressed in escherichia coli (ec-cacel) at temperatures below 10°c, but the expression yield was low. here, rcacel with a silkworm secretion signal (bm-cacel) was succ ...	2014	24848382
structure-based investigation into the functional roles of the extended loop and substrate-recognition sites in an endo-β-1,4-d-mannanase from the antarctic springtail, cryptopygus antarcticus.	endo-β-1,4-d-mannanase from the antarctic springtail, cryptopygus antarcticus (caman), is a cold-adapted β-mannanase that has the lowest optimum temperature (30°c) of all known β-mannanases. here, we report the apo- and mannopentaose (m5) complex structures of caman. structural comparison of caman with other β-mannanases from the multicellular animals reveals that caman has an extended loop that alters topography of the active site. structural and mutational analyses suggest that this extended l ...	2014	25082572
soil invertebrate community change over fuel-contaminated sites on a subantarctic island: an ecological field-based line of evidence for site risk assessment.	a number of fuel spills, of both recent and historic origins, have occurred on world heritage-listed subantarctic macquarie island. sites contaminated by mainly diesel fuels are undergoing remediation by the australian antarctic division. the risks posed by these sites are being managed using a "weight of evidence" approach, for which this study provides a preliminary line of evidence for the ecological assessment component of this site management decision framework. this knowledge is pertinent, ...	2016	26202610
genetic and structural characterization of a thermo-tolerant, cold-active, and acidic endo-β-1,4-glucanase from antarctic springtail, cryptopygus antarcticus.	the cacel gene from antarctic springtail cryptopygus antarcticus codes for a cellulase belonging to the glycosyl hydrolase family 45 (ghf45). phylogenetic, biochemical, and structural analyses revealed that the cacel gene product (cacel) is closely related to fungal ghf45 endo-β-1,4-glucanases. the organization of five introns within the open reading frame of the cacel gene indicates its endogenous origin in the genome of the species, which suggests the horizontal transfer of the gene from fungi ...	2017	28156112
laboratory studies of predation by the antarctic mite gamasellus racovitzai (acarina: mesostigmata).	laboratory investigations of predation by gamasellus racovitzai (acarina: mesostigmata) on cryptopygus antarcticus (insecta: collembola) are described. the predator appeared to search at random, but, when contact with prey had been made, a rapid attack involved looping the forelegs over the prey to hold it whilst the chelicerae moved forward horizontally to puncture the side of the prey. the mean predation rate by deutonymphs, approximately one prey per predator per 12 days, was independent of p ...	1984	28310721
life cycle strategies in two antarctic collembola.	1. populations of two coexisting antarctic collembola were studied in the field and under constant conditions in the laboratory to determine their life cycles and to compare their energy utilisation. 2. in the field parisotoma octooculata completes three to four moults during summer, overwintering either in the egg stage or in the fourth or fifth instars. maturity is reached in the second year, with synchronous oviposition and hatching. cryptopygus antarcticus has many overlapping generations, m ...	1984	28312342