Hemolymph Concentrations Research Articles

Effect of different amount of food and female resource on competitive strategy and agonistic behavior of swimming crab (Portunus trituberculatus)

Obtaining limited resources is an important motivator behind competition in animals. In pond cultures of swimming crabs (Portunus trituberculatus) common resources that cause conflict are food and mates. To explore the effects of different levels of food stimulus (clam extract; CG, control group: 0; LCH, little clam homogenate: 5 mL; ACH, abundant clam homogenate: 25 mL) and mate stimulus (female-conditioned water FCW; SW, seawater: 85 L seawater; LFW, low concentration FCW: 21 L FCW + 64 L seawater; HFW, high concentration FCW: 85 L FCW) on competitive strategies and agonistic behaviors of male crabs, we built an agonistic behavior recording system. We analyzed behavior, changes of oxygen consumption rate (OCR), and the concentrations of glycogen, glucose, and lactate in chelipeds and hemolymph after fighting. The main results revealed the following: (1) With increased perceived availability of food, the frequency of contact and key behaviors was significantly higher in the CG and LCH group than the ACH group. Fight duration in the LCH group was significantly longer than in the ACH group. The fight intensity and OCR of the LCH group were significantly higher than CG and ACH group. The concentration of lactate in hemolymph and glucose in chelipeds of the LCH group were significantly higher than the ACH group. The concentration of glycogen in cheliped muscle of the LCH and ACH group was significantly higher than the CG. (2) The increased concentration of FCW in the HFW group caused the duration of fights and the frequency of contact behaviors to be higher than in the SW group. In the HFW group the key behaviors occurred significantly more than in the SW and LFW groups. Fight intensity was also higher in the HFW group than the other two groups, and the LFW group had higher fight intensity than the SW group. The OCR of LFW and HFW groups were significantly higher than the SW group. The lactate concentrations in hemolymph and chelipeds in the LFW group were significantly higher than those in the SW and LFW groups. The glycogen concentrations in the chelipeds of the LFW and HFW groups were significantly higher than in the SW group. These results showed that the crabs adopt different competitive strategies, either to fight or yield, depending on type and availability of resources. These strategies are associated with costs such as physical risk and energy expenditure. In pond cultures of swimming crabs, increasing the density of food and isolating females from males during the breeding season may help to reduce appendage mutilation or death caused by fighting, thereby increasing aquaculture efficiency.

The Effect of an Entomopathogenic Fungus, Beauveria bassiana on Flight Muscles of The Desert Locust, Schistocerca gregaria Forskal

The infecting flight muscles of adult desert locust Schistocerca gregaria with the entomopathogenic fungus Beauveria bassiana were studied. The entomopathogenic fungus caused mortality percentages 85.56 and 81.11% in 5th nymphal instar and adults after 15 days of treatment; also, LT50 was 9.17 and 10.07 days. The histopathological studies of treated muscles showed that the nucleus, mitochondria, myofibrils and vacuoles were highly deformed. Estimation of total carbohydrates, total lipids and total protein were carried out. The results showed that the Haemolymph content of treated insects was highly affected and all the studied parameters were lower than in the control insects. The decrease in the Haemolymph contents increased with increasing the post-inoculation period.

Effect of E-field at frequency 50 Hz on protein, glucose, and triglycerides concentration in honeybee hemolymph

The development of technology contributes to the increase in the exposure of living organisms to the E-field. While searching for food in the environment, the honeybee is exposed to the influence of this factor. The aim of our research was to determine the E-field effect with a frequency of 50 Hz at various intensities and exposure times on the concentration of protein, glucose, and triglycerides in the honeybee hemolymph. The analysis was carried out on hemolymph taken from at the age of 2 days old worker honeybees. The research showed changes in the tested parameters. Change related to exposure time and field intensity was noticed. The lowest protein concentration in the hemolymph of worker honeybee was observed in all control groups (0.13 mg/mL). The highest in the experimental groups were 23.0 kV/m and 34.5 kV/m with 12 h exposure time (1.04 mg/mL and 1.25 mg/mL). In all experimental groups, statistically significant lower values of glucose concentration in the hemolymph of worker honeybee were observed than in the control groups (23.43–23.55 mmol/l). The highest concentration of triglycerides was observed in the control groups (1.55 mmol/l). Lower but not statistically significant values were observed in the 5.0 kV/m 1 h, 11.5 kV/m 1 and 3 h, and 23.0 kV/m 3 h groups, while the differences were statistically significant in the other groups. The results of the research confirm our earlier observations that the E-field can induce similar reactions in the body to the pathogen. Changes in these important indicators of the body’s nutritional status such as protein, glucose, and triglyceride levels can have long-term effects.

Effect of Starvation as a Population Stress-Factor on the Activation of Covert Baculovirus Infection in the Gypsy Moth

The conditions of entomopathogen persistence in a host-insect organism and the mechanisms of their conversion to the acute form of infection is one of the most important questions for an understanding of epizootics functioning. Here, we estimate the dynamics of the physiological parameters of the gypsy moth (Lymantria dispar L.) responsible for insect protection from antivirals under stress (starvation) and their correlation with the activation of the latent form of L. dispar, multiple nucleopolyhedrosis. We find that starvation leads to an increase in the dopamine concentration in the larval hemolymph and a decrease in the total number of hemocytes, which is associated with the high necrotic cell death. The number of viral carriers in the studied population and their activation level with starvation are estimated to be more than 70%. Polymerase chain reaction analysis showed an increase in the number of virus-positive individuals starting from the first day of starvation. At the same time, the nonspecific mortality of insects began only after 7 days of starvation, whereas the mortality from an activated virus began after 2–3 days of starvation. Thus, we show that at high insect-population density, a lack of food resources plays the leading role in the activation of the covert form of baculovirus infection. When analyzing the dynamics of physiological parameters, we assume that the conversion of a covert baculovirus form into an acute infection can be triggered by necrotic processes induced by starvation.

Alterations in Hemolymph Ion Concentrations and pH in Adult Daphnia magna in Response to Elevations in Major Ion Concentrations in Freshwater.

Increases in the concentrations of major ions (Na+ , K+ , Ca2+ , Mg2+ , Cl- ) in freshwater are a growing concern for ecosystem health. These increases may originate from anthropogenic activities such as road deicing, fracking spills, mining, and fertilizer application and have detrimental effects on freshwater organisms through disturbances in ionoregulation and acid-base balance. The cladoceran Daphnia magna is adapted for active ion uptake and reduction of ion loss to maintain osmotic balance, but alterations in ionic composition of the environmental water are associated with toxicity. In the present study, hemolymph ion concentrations were measured using ion-selective microelectrode techniques. Increases in the hemolymph concentrations of Na+ and K+ correspond to elevations in the concentrations of these ions in ambient water. Water concentrations associated with sustained increases in hemolymph ion concentrations correlate well with median lethal concentration values from previous toxicology studies, indicating that Na+ and K+ concentrations in hemolymph may predict toxicity. When water K+ concentration is increased, a simultaneous increase in water Na+ concentration mitigates the increase in hemolymph K+ concentration, a finding which is consistent with the reported mitigation of K+ toxicity by Na+ . When ambient concentrations of K+ , Na+ , and Cl- are increased, not only is there a rise in hemolymph ion concentration but hemolymph pH is altered and pH regulation appears to be prioritized over regulation of hemolymph Na+ , K+ , and Cl- in D. magna. Environ Toxicol Chem 2021;40:366-379. © 2020 SETAC.

Feed intake, gastro-intestinal transit and haemolymph free amino acids in the shrimp Penaeus monodon are influenced by marine meal supplementation

Aquaculture production can be improved by understanding how ingredients can affect feed intake and digestion. This is an area poorly understood for many aquaculture species, including for the shrimp Penaeus monodon. To investigate these processes, we measured feed intake, the rate at which digesta moves through the gastro-intestinal tract, the change of free amino acids (FAA) circulating in the haemolymph following feeding, and how different test ingredients affect these processes in this species. Diets supplemented with microbial Novacq™ (NQ), krill meal (KM) or whole squid meal (SQ) and a control diet were used across two separate experiments. In the first, feed intake was measured in communally housed shrimp for 60, 120 and 360 min to examine the effects of diet on ingestion. Feed intake after 360 min was greater in shrimp offered the SQ diet while no effect was observed at earlier time points. In the second experiment, individually housed shrimp were used to measure feed intake, the rate at which digesta passed through the gut and the change of individual FAA in the haemolymph over a 30 min period. For this experiment, addition of SQ and NQ increased both the rate at which digesta travels through the gut and post-prandial concentration of FAA in haemolymph at 5 min. Krill meal had the highest haemolymph concentration of amino acids at 10 min and all dietary treatments showed a convergence of haemolymph FAA by 30 min. The different ingredients appear to affect the appearance of FAA in haemolymph through different mechanisms. For SQ, the FAA content of the diet was high, being 2.8 times that of the others (27.6 vs. 10.0 g kg−1), and it is hypothesized that the availability of these FAA resulted in the rapid increase in haemolymph observed for this treatment. In contrast, two other ingredients also led to rapid increases in haemolymph FAA. However, for these diets the amount of FAA present was similar to the control indicating that other characteristics of the meals may be causal. Our data indicate that specific ingredients can increase both the rate at which digesta travels through the gut and the rate of absorption of amino acids and that these mechanisms could explain increases in both feed duration and intake.

Resistance of Biomphalaria alexandrina to Schistosoma mansoni and Bulinus truncatus to Schistosoma haematobium Correlates with Unsaturated Fatty Acid Levels in the Snail Soft Tissue.

Only a fraction of the Biomphalaria and Bulinus snail community shows patent infection with schistosomes despite continuous exposure to the parasite, indicating that a substantial proportion of snails may resist infection. Accordingly, exterminating the schistosome intermediate snail hosts in transmission foci in habitats that may extend to kilometres is cost-prohibitive and damaging to the ecological equilibrium and quality of water and may be superfluous. It may be more cost effective with risk less ecological damage to focus on discovering the parameters governing snail susceptibility and resistance to schistosome infection. Therefore, laboratory bred Biomphalaria alexandrina and Bulinus truncatus snails were exposed to miracidia of laboratory-maintained Schistosoma mansoni and S. haematobium, respectively. Snails were examined for presence or lack of infection association with soft tissue and hemolymph content of proteins, cholesterol, and triglycerides, evaluated using standard biochemical techniques and palmitic, oleic, linoleic, and arachidonic acid, assayed by ultraperformance liquid chromatography-tandem mass spectrometry. Successful schistosome infection of B. alexandrina and B. truncatus consistently and reproducibly correlated with snails showing highly significant (up to P < 0.0001) decrease in soft tissue and hemolymph content of the monounsaturated fatty acid, oleic acid, and the polyunsaturated fatty acids, linoleic, and arachidonic acids as compared to naïve snails. Snails that resisted twice infection had soft tissue content of oleic, linoleic, and arachidonic acid similar to naïve counterparts. High levels of soft tissue and hemolymph oleic, linoleic, and arachidonic acid content appear to interfere with schistosome development in snails. Diet manipulation directed to eliciting excessive increase of polyunsaturated fatty acids in snails may protect them from infection and interrupt disease transmission in a simple and effective manner.

Effectiveness of Calotropis procera Ait. latex against late nymphal instars of Locusta migratoria L. (Orthoptera: Acrididae)

Calotropis procera latex treatments against Locusta migratoria were very persuasive due to mortality efficiency and haemolymph contents of treated nymphs. This study showed the impact of five Usher latex doses 10, 20, 30, 40, and 50 µl by topical applications on 3rd, 4th and 5th. The Ld50 values were 10.3, 10.9 and 12.2µl respectively. The effect of latex usher concentration LD50 (12.2 µl) on haemolymph contents, total carbohydrates, total lipids, total protein and cholesterol of 5th nymphal instar were carried out and showed that the haemolymph content of the treated insects was highly affected and all the studied parameters were lower than the control.

Morphological response of the red palm weevil, Rhynchophorus ferrugineus, to a transient low temperature analyzed by computer tomography and holographic microscopy.

The red palm weevil (RPW), Rhynchophorus ferrugineus, is one of the worst palm pests worldwide. Our study aims to assess its internal and external morphological response to a sudden but transient decrease in the environmental temperature. Wild pre-pupae were subjected for 7 days to either low (5.0±0.5°C) or ambient temperature (23±1°C). Such conditions mimic a thermal anomaly happening in the larval stage most exposed to environmental factors. We quantified the changes undergone at: 1) the internal morphology, by X-Ray Computer Tomography (CT); 2) the 3-D integument' architecture, by Digital Holographic Microscopy (DHM); and 3) the glucose in hemolymph as a potential endogenous cryoprotectant. From X-ray CT we found that both pre-pupae subjected to cold and those remaining at ambient temperature follow a development where their fat body content decreases while a thick and dense cuticle is formed. There was no difference between both groups in the rate of change of fat body/dense tissues. Nevertheless, the cold group presents a slight developmental delay at the level of hemolymph content. Through DHM we again obtained that pre-pupae subjected to cold have not experienced a stop in their development. However, a more obvious developmental delay is now observed in this group at the level of the integumental roughness. Finally, regarding glucose, we found similar levels in control and ambient temperature larvae, while it was clearly increased in 51,7% of those subjected to cold. Our whole results provide morphological and biochemical evidence showing that the larval-pupal transition of the RPW continues almost undisturbed even during the quiescent state induced by a sudden and severe cold event. Nevertheless, a certain developmental delay is observed in both internal and external morphology. Additionally, the increased glucose level only found in the cold group suggests that glucose is part of the RPW cold tolerance strategy.

The effects of magnesium concentration in low‐salinity water on growth of Pacific white shrimp ( Litopenaeus vannamei )

The current study evaluates the effect of different Mg levels in low-salinity (3 g/L) water on growth, survival, haemolymph osmolality, cationic composition in haemolymph, carapace and whole body of Pacific white shrimp, Litopenaeus vannamei. A low-cost salt mixture (LCSM) comprised of Na, K, Ca and Mg concentrations of 298, 9, 17 and 39 mg/L, respectively, in a 1-g/L solution was modified by decreasing the Mg level of LCSM to allow different Mg levels in the culture medium (100, 78, 55, 30, 17, 13 and 12 mg/L). Reconstituted sea salt (RSS) was used as the control treatment with Mg level of 129 mg/L. A 42-day growth trial (initial weight: 0.11 ± 0.01 g and stocking density: 20 shrimp/tank) was carried out in 150-L plastic tanks, each equipped with a fluidized bed biofilter. As Mg2+ level was reduced, there was a subsequent reduction (p < 0.05) in shrimp performance reflected in final weight, weight gain, haemolymph osmolality, osmoregulatory capacity, Mg2+ concentration in haemolymph, carapace and whole body of shrimp paralleled by an increase in feed conversion ratio (FCR). Low haemolymph osmolality and Mg2+ concentrations (p < 0.05) in shrimp haemolymph were found to be indicative of stress, which was ultimately reflected as reduced growth and increased FCR in low Mg2+ concentrations at 3 g/L salinity.

Profiling of methyl farnesoate in relation to female reproductive cycle in the freshwater crab, Travancoriana schirnerae Bott, 1969 (Crustacea: Gecarcinucidae)

ABSTRACT The sesquiterpenoid, methyl farnesoate, produced by the mandibular organ of decapod crustaceans has a variety of functions including the regulation of moulting, reproduction, morphogenesis, behaviour and osmoregulation. This study used gas chromatography and mass spectrometric analysis to measure the haemolymph concentration of methyl farnesoate during various developmental stages of the ovary of the edible freshwater crab Travancoriana schirnerae. The results revealed exceptionally low methyl farnesoate titres in the haemolymph during the avitellogenic and previtellogenic periods (5.7 ± 0.7 and 12.8 ± 1.3 ng/mL, respectively), reaching a peak in the early vitellogenic period (91.8 ± 3.8 ng/mL), followed by a significant fall during the middle and late vitellogenic stages (32.1 ± 2.3 and 22.1 ± 1.6 ng/mL, respectively). The progressive increase and decrease in the haemolymph titre of methyl farnesoate in accordance with the stages of the ovarian cycle clearly indicated the role of this hormone in growth and maturation of the ovary. Furthermore, administration of methyl farnesoate can be exploited as an alternate method to the traditional eyestalk ablation practised for inducing ovarian maturation and spawning.

Insights on the Larvicidal Mechanism of Action of Fractions and Compounds from Aerial Parts of Helicteres velutina K. Schum against Aedes aegypti L.

Viral diseases transmitted by the female Aedes aegypti L. are considered a major public health problem. The aerial parts of Helicteres velutina K. Schum (Sterculiaceae) have demonstrated potential insecticidal and larvicidal activity against this vector. The objective of this research was to investigate the mechanisms of action involved in the larvicidal activity of this species. The cytotoxicity activity of H. velutina fractions and compounds of crude ethanolic extract of the aerial parts of this species was assessed by using fluorescence microscopy and propidium iodide staining. In addition, the production of nitric oxide (NO) and hemocyte recruitment were checked after different periods of exposure. The fluorescence microscopy revealed an increasing in larvae cell necrosis for the dichloromethane fraction, 7,4′-di-O-methyl-8-O-sulphate flavone and hexane fraction (15.4, 11.0, and 7.0%, respectively). The tiliroside did not show necrotic cells, which showed the same result as that seen in the negative control. The NO concentration in hemolymph after 24 h exposure was significantly greater for the dichloromethane fraction and the 7,4′-di-O-methyl-8-O-sulphate flavone (123.8 and 56.2 µM, respectively) when compared to the hexane fraction and tiliroside (10.8 and 8.3 µM, respectively). The presence of plasmocytes only in the dichloromethane fraction and 7,4′-di-O-methyl-8-O-sulphate flavone treatments suggest that these would be the hemocytes responsible for the highest NO production, acting as a defense agent. Our results showed that the larvicidal activity developed by H. velutina compounds is related to its hemocyte necrotizing activity and alteration in NO production.

Exposure to domoic acid causes oxidative stress in bay scallops Argopecten irradians

The neurotoxin domoic acid (DA) is produced by Pseudo-nitzschia spp. during harmful algal blooms and is linked to amnesic shellfish poisoning. This toxin is particularly problematic in the culture of bivalves for human consumption. In this study, we exposed bay scallops to 20, 40, and 60 ng/ml DA and examined toxin accumulation and stress response at 3, 6, 12, 24, 36, and 48 h of exposure. Oxidative stress was determined by measuring the levels of superoxide dismutase (SOD), catalase (CAT), heat shock protein 90 (HSP90), and metallothionein (MT) in the digestive diverticula and/or hemolymph and by determining H2O2 concentration in hemolymph. We also observed histological changes to gills following exposure to DA in order to determine changes in melanization. We found that scallops accumulated a maximum of 2.61 ng/ml DA in their digestive diverticula when exposed to 60 ng/ml. Stress indices rose under higher DA concentrations, and HSP levels increased under exposure to higher concentrations of DA. However, mRNA expression and activity of other stress parameters showed peaks at different times during exposure, with subsequent declines. Epithelial melanization of gills indicated a strong positive response to DA at 60 ng/ml for 48 h (P < 0.05). These results indicate that exposure to DA induces oxidative stress, disrupts metabolism, and has negative effects on the defense systems of bay scallops.

The involvement of a regucalcin in suppressing hemocyte apoptosis in Pacific oyster Crassostrea gigas

Regucalcin (RGN), also known as senescence marker protein-30 (SMP30), plays a vital role in the regulation of Ca2+ homeostasis. In the present study, a regucalcin (designated as CgRGN) was identified from Pacific oyster Crassostrea gigas. The complete cDNA sequence of CgRGN was of 1059 bp, containing an open reading frame of 933 bp which encoded a protein of 310 amino acids. The deduced amino acid sequence of CgRGN shared similarity with other RGNs from the genome of C. gigas as well as other species. The mRNA transcripts of CgRGN were universally detected in all tested tissues, with higher level in hepatopancreas, labial palp, and gills. The relative expression level of CgRGN in hemocytes was significantly up-regulated (p < 0.05) at 3, 12, 72, and 96 h after the stimulation of lipopolysaccharide (LPS). After CgRGN expression was interfered by specific CgRGN-dsRNA, the hemocytes apoptosis rate increased dramatically at 12 h post LPS stimulation (1.56 fold, p < 0.01), compared to the control group. The caspase-3 activity in hemocytes and NO concentration in hemolymph increased significantly (p < 0.05) in dsCgRGN injection oysters. These results collectively indicated that CgRGN could suppress LPS-induced apoptosis and be involved in the immune response of oysters.

Air Temperature and Emersion Time Can Affect the Survival Rate and Ammonium Loading of Swimming Crab Portunus trituberculatus Exposed to Air

Ammonium overloading is a common response of aquatic organisms to air exposure during transport. This study elucidated the relationship between ammonium overloading and mortality of crab Portunus trituberculatus . Additionally, we also explored the effects of emersion time and air temperature on ammonium loading and concomitant physiological change. To test the air temperature effect, the crab was exposed to 16, 23 and 30°C in air for 3 h, respectively, and then recovered in seawater at 23°C for 12 h. To test the emersion time effect, crab was exposed to 23°C in air for 0.5 and 3 h, respectively, and then recovered in seawater at 23°C for 12 h. In the control group, crab was always immersed at 23°C. At each time interval (0.5, 1.5 and 3 h during air exposure and 0.5, 2, 4 and 12 h during recovery), ammonium excretion rate, level of total ammonium, total free amino acids and urea concentration in hemolymph and the hepatopancreas enzyme activity involved in detoxifying ammonium were analysed. Results showed that crab mortality was positively related with emersion time and temperature while ammonium loading was lower at 16 and 30°C than at 23°C. For crab experiencing thermal inconsistence of culture media ( i.e. , 16 or 30°C), they were higher in ammonium excretion rate and activities of ammonium detoxification enzymes, which may be the reason that they had a lower ammonium loading. Prolonged emersion time (3.0 h vs. 0.5 h) increased the ammonium overloading and the activity of ammonium detoxification pathways in crab. Our results demonstrated that emersion-induced ammonium overloading may not be the main reason leading to P. trituberculatus death during air exposure and subsequent recovery. When the culture medium changed, thermal variation, compared with constant temperature, could reduce ammonium overloading in crab by elevating the activities of ammonium detoxification enzymes and ammonium excretion rate during recovery period.

Responses of detoxification enzymes in the midgut of Bombyx mori after exposure to low-dose of acetamiprid

Bombyx mori is an important economic insect. However, the environmental pollution caused by the widespread use of neonicotinoid insecticides has significantly affected the safe production of sericulture. In this paper, we determined the LC50 of acetamiprid, a kind of neonicotinoid insecticides, to 5th instar silkworm larvae, examined its residues in hemolymph and midgut of silkworm after continuous exposure to low-dose of acetamiprid, and investigated the transcription level of detoxifying-related genes and the activity of detoxifying enzymes. The results showed that acetamiprid was highly toxic (24-h LC50, 1.50 mg/L) to silkworm larvae. After continuous exposure to low-dose of acetamiprid (0.15 mg/L), the acetamiprid residue concentrations in hemolymph and midgut were 0.90 and 0.58 μg/mg, respectively, at 48 h, but all decreased at 96 h. At 24 h of acetamiprid exposure, the transcription levels of CYP4M5 and CYP6AB4 and the P450 enzyme activity were significantly enhanced. However, the transcription levels of CarE and CarE-11 and the activity of CarE enzymes were both inhibited by acetamiprid exposure. After 24 h–72 h of acetamiprid exposure, the transcription levels of GSTe3 and GSTd1 were significantly up-regulated, and the GST enzyme activity was also significantly elevated from 48 h to 96 h. Furthermore, the expression levels of FoxO, CncC and Keap1, the key upstream genes of detoxification enzymes, showed a similar trend as the GST genes. These results indicated that acetamiprid was reduced in midgut and the expression of GSTs was upregulated may via FoxO/CncC/Keap1 signaling pathway, which plays a key role in detoxification responses.

Crosstalk among Indoleamines, Neuropeptides and JH/20E in Regulation of Reproduction in the American Cockroach, Periplaneta americana.

Although the regulation of vitellogenesis in insects has been mainly discussed in terms of ‘classical’ lipid hormones, juvenile hormone (JH), and 20-hydroxyecdysone (20E), recent data support the notion that this process must be adjusted in harmony with a nutritional input/reservoir and involvement of certain indoleamines and neuropeptides in regulation of such process. This study focuses on crosstalks among these axes, lipid hormones, monoamines, and neuropeptides in regulation of vitellogenesis in the American cockroach Periplaneta americana with novel aspects in the roles of arylalkylamine N-acetyltransferase (aaNAT), a key enzyme in indoleamine metabolism, and the enteroendocrine peptides; crustacean cardioactive peptide (CCAP) and short neuropeptide F (sNPF). Double-stranded RNA against aaNAT (dsRNAaaNAT) was injected into designated-aged females and the effects were monitored including the expressions of aaNAT itself, vitellogenin 1 and 2 (Vg1 and Vg2) and the vitellogenin receptor (VgR) mRNAs, oocyte maturation and changes in the hemolymph peptide concentrations. Effects of peptides application and 20E were also investigated. Injection of dsRNAaaNAT strongly suppressed oocyte maturation, transcription of Vg1, Vg2, VgR, and genes encoding JH acid- and farnesoate O-methyltransferases (JHAMT and FAMeT, respectively) acting in the JH biosynthetic pathway. However, it did not affect hemolymph concentrations of CCAP and sNPF. Injection of CCAP stimulated, while sNPF suppressed oocyte maturation and Vgs/VgR transcription, i.e., acting as allatomedins. Injection of CCAP promoted, while sNPF repressed ecdysteroid (20E) synthesis, particularly at the second step of Vg uptake. 20E also affected the JH biosynthetic pathway and Vg/VgR synthesis. The results revealed that on the course of vitellogenesis, JH- and 20E-mediated regulation occurs downstream to indoleamines- and peptides-mediated regulations. Intricate mutual interactions of these regulatory routes must orchestrate reproduction in this species at the highest potency.

Renal Purge of Hemolymphatic Lipids Prevents the Accumulation of ROS-Induced Inflammatory Oxidized Lipids and Protects Drosophila from Tissue Damage

Animals require complex metabolic and physiological adaptations to maintain the function of vital organs in response to environmental stresses and infection. Here, we found that infection or injury in Drosophila induced the excretion of hemolymphatic lipids by Malpighian tubules, the insect kidney. This lipid purge was mediated by a stress-induced lipid-binding protein, Materazzi, which was enriched in Malpighian tubules. Flies lacking materazzi had higher hemolymph concentrations of reactive oxygen species (ROS) and increased lipid peroxidation. These flies also displayed Malpighian tubule dysfunction and were susceptible to infections and environmental stress. Feeding flies with antioxidants rescued the materazzi phenotype, indicating that the main role of Materazzi is to protect the organism from damage caused by stress-induced ROS. Our findings suggest that purging hemolymphatic lipids presents a physiological adaptation to protect host tissues from excessive ROS during immune and stress responses, a process that is likely to apply to other organisms.

Copper in Cultured Shrimp Litopenaeus vannamei and Its Reduction in Hepatopancreas After Exposure to Sublethal Nitrite Levels.

This research was to evaluate the load and mobility of Cu in juvenile Litopenaeus vannamei after exposure (48 h) to sublethal concentration of nitrite (5.3 mg/L NO2--N) at a salinity of 3.0 g/L. The hypothesis is that such exposure causes a Cu mobility in the tissues of shrimp. The Cu concentration in exoskeleton, hepatopancreas, muscle and hemolymph in the control group were 38.9 ± 3.0, 2478 ± 256, 11.9 ± 0.2 µg/g (dw) and 95.4 ± 19.1 µg/mL, while in the nitrite exposure, were 46.0 ± 0.1, 1546 ± 173, 11.3 ± 0.3 µg/g (dw) and 118.2 ± 10.5 µg/mL, respectively. Only hepatopancreas exhibited a significant (p < 0.05) reduction (37.6%) between the control and the nitrite exposure. This is evidence that nitrite has a significant effect on Cu accumulation in hepatopancreas when shrimp are exposed to sublethal levels in a salinity of 3 g/L. Results confirm the hypothesis that Cu mobility was only significant in hepatopancreas.

Transcription Analysis of the Stress and Immune Response Genes to Temperature Stress in Ostrinia furnacalis.

Ostrinia furnacalis is one of the most important pests on maize. O. furnacalis larvae are frequently exposed to the temperature challenges such as high temperature in summer and cold temperature in winter in the natural environment. High and low temperature stress, like any abiotic stress, impairs the physiology and development of insects. Up to now, there is limited information about gene regulation and signaling pathways related to the high and cold stress response in O. furnacalis. High-throughput sequencing of transcriptome provides a new approach for detecting stress and immune response genes under high and low temperature stresses in O. furnacalis. In the present study, O. furnacalis larvae were treated with the temperature at 8 and 40°C, and the responses of O. furnacalis larvae to the temperature stress were investigated through RNA-sequencing and further confirmation. The results showed that immune responses were up-regulated in larvae by the cold stress at 8°C while some stress response genes, such as HSP family, GST-2, Bax inhibitor and P450, were significantly increased at 40°C. Furthermore, quantitative real time polymerase chain reaction were performed to quantify the expression levels of immune related genes, such as PGRP-LB, antimicrobial peptides, lysozyme, serine protease and stress response genes such as small HSPs and HSP90, and the expression levels of these genes were similar to the RNA-seq results. In addition, the iron storage protein Ferritin was found to be involved in the response to temperature stress, and the changes of total iron concentration in the hemolymph were, in general, consistent with the expression levels of Ferritin. Taken together, our results suggested that the stress response genes were involved in the defense against the heat stress at 40°C, and the immune responses triggered by cold stress might provide protection for larvae from cold stress at 8°C. More interestingly, our results showed that during the responses to temperature stress, the total iron concentration in hemolymph regulated by Ferritin increased, which might help O. furnacalis in surviving the low and high temperature stress.