Hemolymph Proteins Research Articles

Haemolymph constituents and osmolality as functions of moult stage, body weight, and feeding status in marron, Cherax cainii () and yabbies, Cherax destructor (Clark, 1936).

The study investigates the change in osmolality and haemolymph constituents in marron Cherax cainii and yabbies Cherax destructor associated with moult stages, body weights and their feeding status. A total of 582 haemolymph samples from 5 moult stages (postmoult-AB, intermoult-C, and premoult stages – D0, D1, D2), two body weight classes (2–15 g and 61–75 g) and nutritional status were used for analysis of osmolality, protein, glucose, and ionic concentrations of potassium and chloride following the standard biochemical procedures. The haemolymph protein, glucose, potassium and chloride levels were highest at intermoult and early premoult stages, and lowest at postmoult in both crayfish species. Except protein, no significant differences were seen in analyzed parameters between various weight classes and two species. Haemolymph osmolality, protein and glucose were significantly higher in fed crayfish, whereas no variations in haemolymph potassium and chloride concentrations were observed between the fed and unfed crayfish. Maximum osmolality was recorded at 7–8 h after feeding in both crayfish species. The results showed that the biochemical changes in the haemolymph of marron and yabbies are related to moult stages, body weight and feeding and thus can be used as tools for determining suitable diets.

Proteomic profile of hemolymph and detection of induced antimicrobial peptides in response to microbial challenge in Diatraea saccharalis (Lepidoptera: Crambidae)

Insects are organisms extremely well adapted to diverse habitats, primarily due to their innate immune system, which provides them with a range of cellular and humoral responses against microorganisms. Lepidoptera hemolymph proteins involved in humoral responses are well known; however, there is a lack of knowledge about the sugarcane borer Diatraea saccharalis. In this present work, the hemolymph proteins of this pest insect were studied by applying proteomic methodologies. Two-dimensional electrophoresis (2-DE) gels of proteins extracted from naive larvae and larvae challenged with Escherichia coli (ATCC 11224) and Bacillus subtilis (ATCC 6623) showed an average of 300 spots, and 92 of these spots corresponded in all three 2-DE gels. Forty-one spots were excised and digested with trypsin and analyzed using mass spectrometry. After analysis, 10 proteins were identified, including some proteins of the immune system: β-defensin-like protein, Turandot A-like protein, attacin-like protein, peptidoglycan recognition protein and cyclophilin-like protein. Nine proteins were present in both experimental conditions; however, β-defensin-like protein was present only in hemolymph challenged by B. subtilis. Notably, attacin-like protein was strongly induced by challenge with E. coli, suggesting an immune response against the infection. However, antimicrobial activity was observed in the test zone of microbial growth inhibition of B. subtilis solely with the hemolymph extract of the larvae challenged with B. subtilis. We made for the first time a proteomic profile of the hemolymph of D. saccharalis in which it was possible to identify the presence of important proteins involved in the immune response.

Baculovirus-challenge and poor nutrition inflict within-generation fitness costs without triggering transgenerational immune priming

Invertebrate hosts that survive pathogen challenge can produce offspring that are more resistant to the same pathogen via immune priming, thereby improving the fitness of their offspring in the same pathogen environment. Most evidence for immune priming comes from exposure to bacteria and there are limited data on other groups of pathogens. Poor parental nutrition has also been shown to result in the transgenerational transfer of pathogen resistance and increased immunocompetence. Here, we combine exposure to an insect DNA virus with a change in the parental diet to examine both parental costs and transgenerational immune priming. We challenged the cabbage looper, Trichoplusia ni, with a low dose of the baculovirus, Autographa californica multiple nucleopolyhedrovirus (AcMNPV) and altered dietary protein to carbohydrate ratio (p:c ratio) after virus exposure. Insects fed a low protein diet had lower haemolymph protein concentrations, and exhibited costs of smaller pupae and slower development, while survivors of virus challenge developed more slowly, irrespective of p:c ratio, and those that were virus-challenged and fed on a low protein diet showed a reduction in haemocyte density. In addition, AcMNPV-challenged parents laid fewer eggs earlier in egg laying although egg size was the same as for unchallenged parents. There was no evidence for increased resistance to AcMNPV (immune priming) or changes in haemocyte number (as proxy for constitutive cellular immunity) in the offspring either as a result of parental AcMNPV-challenge or low dietary p:c ratio. Therefore, although pathogen-challenge and nutritional changes can affect host development and reproduction, this does not necessarily translate into transgenerational immune priming. Our findings contrast with an earlier study on another type of baculovirus, a granulovirus, where immune priming was suggested. This indicates that transgenerational immune priming is not universal in invertebrates and is likely to depend on the host-pathogen system, or the level of pathogen exposure and the type of dietary manipulation. Identifying whether immune priming or transgenerational effects are relevant in field populations, remains a challenge.

Thermal biology of the sub-polar-temperate estuarine crab Hemigrapsus crenulatus (Crustacea: Decapoda: Varunidae).

ABSTRACTOptimum temperatures can be measured through aerobic scope, preferred temperatures or growth. A complete thermal window, including optimum, transition (Pejus) and critical temperatures (CT), can be described if preferred temperatures and CT are defined. The crustacean Hemigrapsus crenulatus was used as a model species to evaluate the effect of acclimation temperature on: (i) thermal preference and width of thermal window, (ii) respiratory metabolism, and (iii) haemolymph proteins. Dependant on acclimation temperature, preferred temperature was between 11.8°C and 25.2°C while CT was found between a minimum of 2.7°C (CTmin) and a maximum of 35.9°C (CTmax). These data and data from tropical and temperate crustaceans were compared to examine the association between environmental temperature and thermal tolerance. Temperate species have a CTmax limit around 35°C that corresponded with the low CTmax limit of tropical species (34–36°C). Tropical species showed a CTmin limit around 9°C similar to the maximum CTmin of temperate species (5–6°C). The maximum CTmin of deep sea species that occur in cold environments (2.5°C) matched the low CTmin values (3.2°C) of temperate species. Results also indicate that the energy required to activate the enzyme complex (Ei) involved in respiratory metabolism of ectotherms changes along the latitudinal gradient of temperature.

Protein identification and in vitro digestion of fractions from Tenebrio molitor

The nutritional value of insect protein is evaluated not only in amino acid composition, but also in protein digestibility. The general amino acid composition of Tenebrio molitor has been reported before, but limited knowledge is available on its digestibility. The objective of this study was to investigate in vitro protein digestibility of whole T. molitor larvae, a water-soluble fraction (supernatant) and water-insoluble fractions (pellet and residue), and to identify which proteins were present in the fractions studied. The digestibility of the supernatant fraction (~80 %) was much higher than that of pellet (~50 %) and residue (~24 %) after in vitro gastroduodenal digestion as was determined using the o-phthaldialdehyde (OPA) method. More proteins were digested after pepsin/pancreatin digestion than after only pepsin digestion. The most abundant proteins in the supernatant were hemolymph protein (~12 kDa), alpha-amylase (~50 kDa, a putative allergen), and muscle proteins (e.g. actin 30–50 kDa) in the pellet fraction as determined from LC–MS/MS and SDS-PAGE. In conclusion, the proteins in the soluble fraction that contained hemolymph proteins were more easily digestible than the insoluble, muscle protein-containing fractions.

Assessment of electron beam irradiation induced proteomic changes and its effect on the development of silkworm, Bombyx mori (Bombycidae: Lepidoptera)

The present study has been designed to determine the hemolymph protein changes induced by EBI using Microtron (ranges from 20 to 100Gy) on the 5th instar larvae of silkworm, Bombyx mori using SDS–PAGE. The EBI did not caused any impact on 5th instar larval hemolymph proteins, however a significant reduction of pupal hemolymph proteins such as lipophorin (250kDa), vitellogenin (180kDa), storage protein (76–80kDa) and a 30kDa protein was observed through SDS–PAGE and densitometry analysis. These proteins are known to play a crucial role in various developmental processes including transport of lipids, as amino acid reservoir for providing precursors for egg and cuticle formation and immunity of B. mori. Further, a decrease of antioxidant enzymes such as Superoxide Dismutase (SOD) and Catalase (CAT) in the EBI treated larval and pupal hemolymph was observed. In addition, a negative influence on growth characteristics and appearance of pupal deformity was noted. This may be due to damage in hemolymph proteins, when the larvae were exposed to EBI at >80Gy.

Influence of different proteinaceous diets on consumption, brood rearing,and honey bee quality parameters under isolation conditions

This study was carried out to evaluate the efficacy of 5 proteinaceous diets on honey bees under isolation conditions. The diets were soybean meal, mesquite pod powder, date paste, Feedbee®, and corn gluten, along with control colonies (bees fed naturally on pollens). These 5 diets were supplied to honey bee colonies under isolation conditions, except for the control group. Food consumption amount, brood rearing activity, and some physiological parameters of the honey bees were measured. The best consumption amount was for date paste, followed by Feedbee, mesquite, and corn gluten, respectively. Concerning brood rearing activity, the highest mean of sealed brood cells was 174.7 cells/colony in colonies fed on Feedbee, while no brood was reared in colonies fed on soybean meal. The fresh weight, dry matter, and protein content of fully grown larvae and newly emerged workers were higher in colonies fed on bee bread than the colonies fed on the artificial diets. Total soluble solids %, total hemolymph count, and hemolymph protein % were varied among tested diets. Feedbee was able to enhance brood rearing, but Feedbee is expensive and not available in the local markets of Saudi Arabia. Hence, beekeepers are advised to use mesquite pod flour as a pollen substitute in dearth periods.

Variation in Development and DNA Methylation of Spodoptera exigua Fed with Different Diets

Physiological plasticity of insects can be closely related with their epigenetic change. This hypothesis was tested using a polyphagous lepidopteran insect, Spodoptera exigua, by assessing the effects of different diets on development and DNA methylation. Three different diets (Welsh onion (WO), Chinese cabbage (CC), artificial diet (AD)) were assessed by feeding a cohort of larvae from neonate to last instar. There were significant differences in larval developmental rate, pupal weight and adult emergence according to diet treatments. AD-fed larvae exhibited the fastest developmental rate along with the highest pupal weight and adult emergence. Among natural hosts, WO was more favorable for development of S. exigua than CC. Total hemolymph proteins and sugars in the last instar larvae were varied among different diets. Gene expression of an insulin-like peptide (SeILP1) presumably associated with development was also varied among diets. Cytosine methylation of genomic DNA was assessed using a monoclonal antibody. Genomic DNA of S. exigua larvae was methylated. DNA methylation was apparently varied among different diet-fed larvae. The facts that a cohort of S. exigua was differentiated in developmental rate and cytosine methylation by different diets suggest that epigenetic factor(s) may play a crucial role in the physiological plasticity.

Climate change, nutrition and immunity: Effects of elevated CO2 and temperature on the immune function of an insect herbivore

Balanced nutrition is fundamental to health and immunity. For herbivorous insects, nutrient-compositional shifts in host plants due to elevated atmospheric CO2 concentrations and temperature may compromise this balance. Therefore, understanding their immune responses to such shifts is vital if we are to predict the outcomes of climate change for plant–herbivore–parasitoid and pathogen interactions. We tested the immune response of Paropsis atomaria Olivier (Coleoptera: Chrysomelidae) feeding on Eucalyptus tereticornis Sm. seedlings exposed to elevated CO2 (640μmolmol−1; CE) and temperature (ambient plus 4°C; TE). Larvae were immune-challenged with a nylon monofilament in order to simulate parasitoid or pathogen attack without other effects of actual parasitism or pathology. The cellular (in vivo melanisation) and humoral (in vitro phenoloxidase PO activity) immune responses were assessed, and linked to changes in leaf chemistry. CE reduced foliar nitrogen (N) concentrations and increased C:N ratios and concentrations of total phenolics. The humoral response was reduced at CE. PO activity and haemolymph protein concentrations decreased at CE, while haemolymph protein concentrations were positively correlated with foliar N concentrations. However, the cellular response increased at CE and this was not correlated with any foliar traits. Immune parameters were not impacted by TE. Our study revealed that opposite cellular and humoral immune responses occurred as a result of plant-mediated effects at CE. In contrast, elevated temperatures within the tested range had minimal impact on immune responses. These complex interactions may alter the outcomes of parasitoid and pathogen attack in future climates.

Alternations in parasitological, biochemical and molecular parameters of Biomphalaria alexandrina snails, intermediate host of Schistosoma mansoni, induced post exposure to the proposed snail biocontrol agent Phasmarhabditis hermaphrodita nematode

ObjectiveTo elucidate the effect of the parasitic nematode Phasmarhabditis hermaphrodita (P. hermaphrodita) as snail biocontrol agent on biological, parasitological, biochemical and molecular parameters of Biomphalaria alexandrina (B. alexandrina) snails, the intermediate host of Schistosoma mansoni (S. mansoni). MethodsB. alexandrina snails (5–6 mm) were exposed to the 3rd stage larvae of the nematode P. hermaphrodita and/or S. mansoni miracidia for 24 h. Thereafter, they were thoroughly washed with clean dechlorinated water and transferred to clean aquaria for recovery and recording deteriorations in their biological, parasitological, biochemical and molecular parameters. ResultsThe results showed that snails were dead after 24 h of exposure to 100 nematode larvae/snail. Cercarial production/infected snail was reduced to 68 cercariae/snail post simultaneous exposure to 40 nematode larvae and 10 S. mansoni miracidia compared to control (783.7 cercariae/snail) (P < 0.001). Similarly, the total hemocytes of snails increased to 3 800 hemocytes/mL hemolymph by the 3rd day post exposure compared to 2 100 hemocytes/mL for control group (P < 0.001). The results, also, elicited a significant elevation in activities of the enzymes aspartate transaminase, alanine transaminase, acid phosphatase and alkaline phosphatase in hemolymph of snails exposed to nematode larvae. Similar pattern was recoded for activities of catalase, glutathione reduced and nitric oxide in snails' digestive gland. Meanwhile total protein and albumin concentrations in snails' hemolymph and lipid peroxide in digestive gland tissues were decreased. The electrophoretic analysis of ovotestis-digestive gland complex of snails exposed to the nematode larvae indicated an increase in RNA intensity, while no significant changes were recorded in the molecular weight of intact DNA compared to control snails. ConclusionsIt is concluded that exposure of B. alexandrina snails to P. hermaphrodita nematode deteriorates their biological, parasitological, biochemical and molecular parameters, rendering them to be unsuitable for schistosomiasis transmission. However, comprehensive tests are needed to determine efficacy of P. hermaphrodita as a schistosomiasis biocontrol agent aiming to incorporate in control program of this parasite.

Oyster viperin retains direct antiviral activity and its transcription occurs via a signalling pathway involving a heat-stable haemolymph protein.

Little is known about the response of non-model invertebrates, such as oysters, to virus infection. The vertebrate innate immune system detects virus-derived nucleic acids to trigger the type I IFN pathway, leading to the transcription of hundreds of IFN-stimulated genes (ISGs) that exert antiviral functions. Invertebrates were thought to lack the IFN pathway based on the absence of IFN or ISGs encoded in model invertebrate genomes. However, the oyster genome encodes many ISGs, including the well-described antiviral protein viperin. In this study, we characterized oyster viperin and showed that it localizes to caveolin-1 and inhibits dengue virus replication in a heterologous model. In a second set of experiments, we have provided evidence that the haemolymph from poly(I : C)-injected oysters contains a heat-stable, protease-susceptible factor that induces haemocyte transcription of viperin mRNA in conjunction with upregulation of IFN regulatory factor. Collectively, these results support the concept that oysters have antiviral systems that are homologous to the vertebrate IFN pathway.

The spider hemolymph clot proteome reveals high concentrations of hemocyanin and von Willebrand factor-like proteins

Arthropods include chelicerates, crustaceans, and insects that all have open circulation systems and thus require different properties of their coagulation system than vertebrates. Although the clotting reaction in the chelicerate horseshoe crab (Family: Limulidae) has been described in details, the overall protein composition of the resulting clot has not been analyzed for any of the chelicerates. The largest class among the chelicerates is the arachnids, which includes spiders, ticks, mites, and scorpions. Here, we use a mass spectrometry-based approach to characterize the spider hemolymph clot proteome from the Brazilian whiteknee tarantula, Acanthoscurria geniculata. We focused on the insoluble part of the clot and demonstrated high concentrations of proteins homologous to the hemostasis-related and multimerization-prone von Willebrand factor. These proteins, which include hemolectins and vitellogenin homologous, were previously identified as essential components of the hemolymph clot in crustaceans and insects. Their presence in the spider hemolymph clot suggests that the origin of these proteins' function in coagulation predates the split between chelicerates and mandibulata. The clot proteome reveals that the major proteinaceous component is the oxygen-transporting and phenoloxidase-displaying abundant hemolymph protein hemocyanin, suggesting that this protein also plays a role in clot biology. Furthermore, quantification of the peptidome after coagulation revealed the simultaneous activation of both the innate immune system and the coagulation system. In general, many of the identified clot-proteins are related to the innate immune system, and our results support the previously suggested crosstalk between immunity and coagulation in arthropods.

Proteomic analysis of hemolymph from poly(I:C)-stimulated Crassostrea gigas.

Synthetic double stranded RNA (Poly(I:C)) injection of Crassostrea gigas results in a systemic antiviral response involving many evolutionary conserved antiviral effectors (ISGs). Compared to mammals, the timing of C.gigas ISG expression to viral or poly(I:C) injection is delayed (>12h p.i.). It could be interpreted that a cytokine is responsible for the systemic, but delayed expression of C.gigas ISGs. We therefore analysed the acellular fraction of C.gigas hemolymph by two-dimensional electrophoresis (2-DE) to identify hemolymph proteins induced by poly(I:C). Poly(I:C) injection increased the relative intensity of four protein spots. These protein spots were identified by tandem mass spectrometry (LC-MS/MS) as a small heat shock protein (sHSP), poly(I:C)-inducible protein 1 (PIP1) and two isoforms of C1q-domain containing protein (C1qDC). RT-qPCR analysis confirmed that the genes encoding these proteins are induced in hemocytes of C.gigas injected with poly(I:C) (p<0.05). Proteomic data from this experiment corroborates previous microarray and whole transcriptome studies that have reported up-regulation of C1qDC and sHSP during mass mortality events among farmed oysters.

Shotgun analysis of the marine mussel Mytilus edulis hemolymph proteome and mapping the innate immunity elements.

The marine mussel innate immunity provides protection to pathogen invasion and inflammation. In this regard, the mussel hemolymph takes a main role in the animal innate response. Despite the importance of this body fluid in determining the physiological condition of the animal, little is known about the molecular mechanisms underlying the cellular and humoral responses. In this work, we have applied a MS (nano-LC-MS/MS) strategy integrating genomic and transcriptomic data with the aim to: (i) identify the main protein functional groups that characterize hemolymph and (ii) to map the elements of innate immunity in the marine mussel Mytilus edulis hemolymph proteome. After sample analysis and first protein identification based on MS/MS data comparison, proteins with unknown functions were annotated with blast using public database (nrNCBI) information. Overall 595 hemolymph proteins were identified with high confidence and annotated. These proteins encompass primary cellular metabolic processes: energy production and metabolism of biomolecules, as well as processes related to oxidative stress defence, xenobiotic detoxification, drug metabolism, and immune response. A group of proteins was identified with putative immune effector, receptor, and signaling functions in M. edulis. Data are available via ProteomeXchange with identifier PXD001951 (http://proteomecentral.proteomexchange.org/dataset/PXD001951).

Effect of lufox on haemolymph and ovarian protein in the soft tick, Argas persicus.

Changes in the total protein titer in the haemolymph (HL) and ovaries (Ov) of mated fed normal and Lufox treated female Argas persicus during the reproductive cycle and in the HL of normal male were studied. Tick engorgement was followed by an intial drop of the HL total protein concentration immediately and up to the 2nd and 3rd day after feeding (daf), then by a gradual increase on next days to reach maximum on 4-7 and 6-7 daf in the female and male, respectively. The level in the female HL was much higher than that in the male during vitellogenesis and the onset of oviposition. In the ovaries of normal female the total protein level increased gradually immediately up to 2 daf and evidently on 3 daf to reach a maximum on 5-7 daf. The protein level in the HL and ovaries decreased after the completion of oviposition (20 daf). Topical application of a single dose of 50 ppm Lufox on the mated female A. persicus on the 3rd daf interfered with protein production causing a significant reduction in the total protein level in the HL (43.04-55.57%) and ovaries (36.47-46.43%) during vitellogenesis on 4-7 daf and in eggs (15.38%) freshly deposited by the treated female. Also, application of Lufox on the 3rd daf altered the normal pattern of change in the level of HL and ovary total protein during the reproductive cycle by preventing any appreciable increase in the level on next days (4-7 daf) where the level remained constant in the ovaries and even decreased in the HL (4-5 daf).

Effects of Oral Exposure to Fungicides on Honey Bee Nutrition and Virus Levels.

Sublethal exposure to fungicides can affect honey bees (Apis mellifera L.) in ways that resemble malnutrition. These include reduced brood rearing, queen loss, and increased pathogen levels. We examined the effects of oral exposure to the fungicides boscalid and pyraclostrobin on factors affecting colony nutrition and immune function including pollen consumption, protein digestion, hemolymph protein titers, and changes in virus levels. Because the fungicides are respiratory inhibitors, we also measured ATP concentrations in flight muscle. The effects were evaluated in 3- and 7-d-old worker bees at high fungicide concentrations in cage studies, and at field-relevant concentrations in colony studies. Though fungicide levels differed greatly between the cage and colony studies, similar effects were observed. Hemolymph protein concentrations were comparable between bees feeding on pollen with and without added fungicides. However, in both cage and colony studies, bees consumed less pollen containing fungicides and digested less of the protein. Bees fed fungicide-treated pollen also had lower ATP concentrations and higher virus titers. The combination of effects we detected could produce symptoms that are similar to those from poor nutrition and weaken colonies making them more vulnerable to loss from additional stressors such as parasites and pathogens.

Purification and molecular cloning of hemocyanin from Fenneropenaeus merguiensis(de Man, 1888): response to Vibrio harveyi exposure

Hemocyanin (HC) was purified from hemolymph of Fenneropenaeus merguiensis(de Man, 1888). Purified HC showed one band in non-denaturing PAGE with a molecular mass of 457 kDa, determined by gel filtration. Using an ELISA, HC content was 85.6% of total hemolymph protein. HC’s hexamer form contained no phenoloxidase activity under trypsin or SDS activation. FmHC, cloned from F. merguiensis, had a full-length cDNA comprised of 2128 bp with an open reading frame encoding a peptide of 661 amino acids with two Cu-binding sites. Expression of FmHCwas found only in the hepatopancreas where it was up-regulated after exposure to Vibrio harveyiinjection into shrimp and with tissue incubations. HC protein levels in the hemolymph of bacterial injected shrimp also increased. FmHCexpression was also up-regulated after shrimp were challenged with a lipopolysaccharide, which is a surface component of gram-negative bacteria. These results indicate that HC is inducible and up-regulated in response to pathogenic challenge, confirming that HC participates in the innate immune response in F. merguiensis.

Honey bee colonies provided with natural forage have lower pathogen loads and higher overwinter survival than those fed protein supplements

Malnutrition is a major cause of colony losses. In managed hives, bees are fed protein supplements (PS) during pollen shortages. If bees were provided with natural forage instead of PS, would they have lower pathogen levels and higher queen and colony survival? We addressed this question by either providing colonies with forage (Brassica rapa—rapini) or feeding them PS from November to February. Soluble protein concentrations in the PS were lower than the rapini pollen as were levels of most amino acids. Nurse bees digested less of the protein in PS than the pollen. Hemolymph protein titers in nurse bees and colony growth did not differ between those fed PS or foraging on rapini. However, colonies fed PS had higher levels of black queen cell virus and Nosema and greater queen losses, indicating that natural forage might improve overwintering survival.

Comparative proteomic analysis of hemolymph proteins from Autographa californica multiple nucleopolyhedrovirus (AcMNPV)-sensitive or -resistant silkworm strains during infections

We reported previously that baculovirus AcMNPV host-ranges in silkworm strains are controlled by a novel third chromosomal locus. To further isolate the potential host factor and uncover the functional pathway involved, in this study we analyzed hemolymph proteins from AcMNPV-resistant or -sensitive silkworm strains infected with baculoviruses. All the protein spots from 2D electrophoresis were characterized by MALDI-TOF MS and further systematically assessed for differentially regulated proteins at different stages of infection. Subsequently, six candidates were selected for functional analysis using Bm5 cells, where the candidates were knocked-down or overexpressed. We observed that mRNA expression levels of beta-N-acetylglucosaminidase and prophenoloxidase subunit 2 are significantly upregulated during AcMNPV infections in Bm5 cells. Ultimately, we found that RNA interference of ribosomal protein RpL34 causes serious damages to cell viability as well as abortive infection, indicating that ribosomal components are essential for productive baculovirus infection.

Physiological responses of the ghost shrimp Neotrypaea uncinata (Milne Edwards 1837) (Decapoda: Thalassinidea) to oxygen availability and recovery after severe environmental hypoxia

Hypoxia is a common and widespread phenomenon in aquatic ecosystems, imposing a significant challenge for the animals that inhabit such waters. In different habitats, however, the characteristics of these hypoxic events may differ, therefore imposing different challenges. We investigated the tolerance of adult ghost shrimp Neotrypaea uncinata (an intertidal mudflat dweller) to different partial pressures of oxygen (pO2), severe hypoxia (2kPa) and recovery from hypoxia after different exposure times, mimicking the natural tidal cycle (6h and 12h). We calculated critical oxygen tension and categorize the adult ghost shrimps as oxyregulators (R value=75.27%). All physiological measurements (metabolic rate, oxyhemocyanin, hemolymph protein and lactate concentrations) were affected by exposure to low partial pressures of oxygen, but most of them recovered (with exception of metabolic rate) control values (21kPa) after 6h under normoxic conditions. Low metabolic rate, high release of hemolymphatic proteins and anaerobic metabolism are suggested as response mechanisms to overcome hypoxic events during low tide.