Phenoloxidase Activity Research Articles

Effect of fermented lemon peel as a functional feed additive on growth, non-specific immune responses, and Vibrio alginolyticus resistance in whiteleg shrimp, Litopenaeus vannamei

The study evaluated the impact of lemon peel fermented with Lactobacillus plantarum (FLP) being a practical feed additive, and its effects on growth performance, non-specific immune indicators, and disease resistance for whiteleg shrimp (Litopenaeus vannamei). The FLP was incorporated into the control diet at a graded level of 0%, 1%, 2%, and 3%. Four experimental feeds were randomly assigned to 4 replicates of L. vannamei with average weight of 2.37 g in a recirculation system for 56 days. Shrimp fed the four diets revealed similar (p > 0.05) weight gain percentage (489.01%−520.25%), feed conversion rate (2.46–2.70), protein efficiency ratio (1.05–1.14), and survival (78.75%−90.00%) after the feeding trial. Total hemocyte count (THC) was higher in shrimp delivered feeds containing 1% and 2% FLP whereas the phenoloxidase (PO) activity was advanced in shrimp fed the feed containing 2% FLP comparing with the FLP-free control group. In the V. alginolyticus challenge test, final survival after 72 h injection was higher in shrimp delivered feeds containing 2% and 3% FLP (66.67%−70.00%) than that in the control group (43.33%). The findings emphasize that fermented lemon peel is a potential functional feed additive on improving immunity and disease resistance for whiteleg shrimp, and showing no negative effects on growth and hepatopancreas morphology. An inclusion rate of 2% FLP is suggested for whiteleg shrimp to maximize the THC and PO activity and resistance ability to V. alginolyticus.

Exploring the effects of astragalus polysaccharide food supplementation on growth performance, immunity, antioxidant capacity, and intestinal microflora in Chinese mitten crabs

Astragalus polysaccharide (APS) is the main active ingredient in astragalus membranaceus, which is composed of rhamnose, arabinose, xylose, mannose, galactose, and glucose. This research evaluated dietary addition with APS effects on growth, non-specific immune, antioxidant status and intestinal microbiota of Chinese mitten crabs. Altogether 288 crabs with intact appendages were irregularly assigned 12 crabs per replicate to 24 tanks with 6 replicates per treatment. Crabs were given a basal diet in different groups containing 0 (control group), 500, 1000, and 2000 mg/kg of APS, respectively. The results indicated that the dietary APS addition increased the specific growth rate and percentage weight gain, serum phenoloxidase and lysozyme activities, increased superoxide dismutase and glutathione peroxidase activities of serum and hepatopancreas, reduced the feed conversion ratio of Chinese mitten crabs (P < 0.05). APS addition quadratically increased acid phosphatase levels, decreased the malondialdehyde levels of Chinese mitten crabs (P < 0.05). APS inclusion linearly and quadratically increased hepatopancreas mRNA expression levels of TLR2, MyD88 and Tube of crabs (P < 0.05). Principal component analysis showed that the four groups had different composition of the intestinal microbiota in Chinese mitten crabs. On the other hand, this addition decreased the Chao1, Shannon indexes, abundance of phyla Bacteroidota, increased the abundance of phyla Firmicutes and genus Candidatus_Bacilloplasma in intestine microbiota of Chinese mitten crabs compared with the control (P < 0.05). The level of APS to the diet of Chinese mitten crabs with a 1000 mg/kg inclusion was better compared to its counterparts with 500 and 2000 mg/kg inclusions according to the better results on growth, immunity, and antioxidant capacity. In summary, dietary APS inclusion enhanced growth performance via improving antioxidant function, non-specific immunity, modulating the Toll/NF-κB pathway and proPO system, and ameliorating the intestinal flora in Chinese mitten crabs. The optimal level of supplemented APS in the diet was 1000 mg/kg.

Evaluating the imazethapyr herbicide mediated regulation of phenol and glutathione metabolism and antioxidant activity in lentil seedlings.

The imidazolinone group of herbicides generally work for controlling weeds by limiting the synthesis of the aceto-hydroxy-acid enzyme, which is linked to the biosynthesis of branched-chain amino acids in plant cells. The herbicide imazethapyr is from the class and the active ingredient of this herbicide is the same as other herbicides Contour, Hammer, Overtop, Passport, Pivot, Pursuit, Pursuit Plus, and Resolve. It is commonly used for controlling weeds in soybeans, alfalfa hay, corn, rice, peanuts, etc. Generally, the herbicide imazethapyr is safe and non-toxic for target crops and environmentally friendly when it is used at low concentration levels. Even though crops are extremely susceptible to herbicide treatment at the seedling stage, there have been no observations of its higher dose on lentils (Lens culinaris Medik.) at that stage. The current study reports the consequence of imazethapyr treatment on phenolic acid and flavonoid contents along with the antioxidant activity of the phenolic extract. Imazethapyr treatment significantly increased the activities of several antioxidant enzymes, including phenylalanine ammonia lyase (PAL), phenol oxidase (POD), glutathione reductase (GR), and glutathione-s-transferase (GST), in lentil seedlings at doses of 0 RFD, 0.5 RFD, 1 RFD, 1.25 RFD, 1.5 RFD, and 2 RFD. Application of imazethapyr resulted in the 3.2 to 26.31 and 4.57-27.85% increase in mean phenolic acid and flavonoid content, respectively, over control. However, the consequent fold increase in mean antioxidant activity under 2, 2- diphenylpicrylhdrazyl (DPPH) and ferric reducing antioxidant power (FRAP) assay system was in the range of 1.17-1.85 and 1.47-2.03%. Mean PAL and POD activities increased by 1.63 to 3.66 and 1.71 to 3.35-fold, respectively, in agreement with the rise in phenolic compounds, indicating that these enzyme's activities were modulated in response to herbicide treatment. Following herbicide treatments, the mean thiol content also increased significantly in corroboration with the enhancement in GR activity in a dose-dependent approach. A similar increase in GST activity was also observed with increasing herbicide dose.

Effect of drainage on microbial transformation processes of soil organic carbon in two typical wetlands of China

Wetlands store one third of global soil organic carbon (SOC) and are strongly affected by artificial drainage. The impact of drainage-induced water-table decline on carbon cycling in different wetlands, particularly microbial transformation processes, remains unclear. To address this knowledge gap, we collected soil samples from two typical wetlands of China (a nutrient-poor bog located in Dajiuhu and a nutrient-rich fen in Hongyuan) and conducted an incubation experiment with the addition of 13C-labeled glucose to analyze the effects of short- and long-term drainage on SOC decomposition, extracellular enzyme activity, microbial carbon use efficiency (CUE), and microbial carbon accumulation efficiency (CAE). The results showed that both short- and long-term drainage significantly increased SOC decomposition rates in both wetlands (from 1.47 μg C·g-1·h-1 in submerged soils to 2.47 μg C·g-1·h-1 in drained soils), microbial biomass carbon derived from glucose (from 0.21 mg C·g-1 to 1.00 mg C·g-1) and CAE (from 0.29 to 0.73), but did not alter CUE (ranging from 0.34 to 0.86). Long-term drainage increased α-glucosidase activity in the Dajiuhu wetland and decreased β-glucosidase and phenol oxidase activities in the Hongyuan wetland. In conclusion, drainage enhanced the 'microbial carbon pump' and its efficiency in wetlands mainly via increasing microbial intracellular metabolism (including respiration), but also acce-lerated SOC decomposition.

Effects of a phytobiotic-based additive on the growth, hepatopancreas health, intestinal microbiota, and Vibrio parahaemolyticus resistance of Pacific white shrimp, Litopenaeus vannamei.

Vibrio genus is a common pathogen in aquaculture and causes acute hepatopancreatic necrosis disease (AHPND) and massive mortality of shrimp. Many studies have suggested that a single functional ingredient such as plant extract or organic acid can reduce the dependence on antibiotics and promote the growth and immunity of aquatic animals. In this study, we evaluated the effects of a phytobiotic-based compound additive (Sanacore® GM, SNGM), which had a successful trajectory of commercial application in fish farming. However, its effects on the hepatopancreas health and intestinal microbiota of shrimp after Vibrio challenge have not been well evaluated. In the present study, Pacific white shrimp were fed diets with or without supplementation of SNGM, and the SNGM grades were 0-g/kg (CON), 3-g/kg (SNGM3), and 5-g/kg (SNGM5) diets. The feed trial lasted 60 days, after which a Vibrio parahaemolyticus challenge was performed. The results showed that compared to the CON group, both the SNGM3 and SNGM5 groups had a significantly higher weight gain and a lower feed conversion ratio as well as higher survival after Vibrio parahaemolyticus challenge. In the growth trial, the SNGM3 group had a significantly increased total protein, albumin concentration, and acid phosphatase activity in hemolymph compared to the CON group. In the challenge experiment, the SNGM3 and SNGM5 groups had increased albumin and glucose contents as well as the activities of phenoloxidase, lysozyme, alkaline phosphatase, and superoxide dismutase in hemolymph. Both the SNGM3 and SNGM5 groups had improved morphology of the hepatopancreas and intestine. The SNGM5 group had alleviated gut microbiota dysbiosis induced by Vibrio infection by increasing the potential probiotic bacterium abundance (Shewanella) and decreasing the potential pathogenic bacteria abundance (Vibrio, Photobacteriuma, Pseudoalteromonas, and Candidatus_Bacilloplasma). In conclusion, the dietary phytobiotic-based additive at 3-g/kg level increased the growth and Vibrio parahaemolyticus resistance of Pacific white shrimp by promoting immune-related enzyme activities and improving the morphological structure of the hepatopancreas and intestine and the intestinal microbiota composition.

Screening of insect immune suppressors using a recombinant phospholipase A2 of a lepidopteran insect.

Phospholipase A2 (PLA2 ) catalyzes phospholipids at the sn-2 position to release free fatty acids, including arachidonic acid (AA) or its precursor. The free AA is then oxygenated into different eicosanoids, which mediate the diverse physiological processes in insects. Any inhibition of the PLA2 catalysis would give rise to serious malfunctioning in insect growth and development. An onion moth, Acrolepiopsis sapporensis, encodes four different PLA2 genes (As-PLA2 A-As-PLA2 D), in which As-PLA2 A is dominantly expressed at all developmental stages and in different larval tissues. RNA interference of the As-PLA2 A expression significantly reduced the PLA2 activity of A. sapporensis, which suffered from immunosuppression. A recombinant As-PLA2 A protein was purified from a bacterial expression system, which exhibited a typical Michaelis-Menten kinetics and hence susceptible to a specific inhibitor to sPLA2 and dithiothreitol. A total of 19 bacterial metabolites derived from Xenorhabdus and Photorhabdus were screened against the recombinant As-PLA2 A. Five potent metabolites were highly inhibitory and followed a competitive enzyme inhibition. These five inhibitors suppressed the immune responses of A. sapporensis by inhibiting hemocyte-spreading behavior and phenoloxidase activity. However, an addition of AA could significantly rescue the immunosuppression induced by the selected inhibitors. These studies suggest that the recombinant As-PLA2 A protein can be applied for high-throughput screening of insect immunosuppressive compounds.

Immune signaling pathways in Rhodnius prolixus in the context of Trypanosoma rangeli infection: cellular and humoral immune responses and microbiota modulation.

Rhodnius prolixus is a hematophagous insect and one of the main vectors for Trypanosoma cruzi and Trypanosoma rangeli parasites in Latin America. Gut microbiota and insect immune responses affect T. cruzi and T. rangeli infection within triatomines. Particularly the Toll and IMD signaling pathways activations and how they orchestrate the antimicrobial peptides (AMPs) expressions in R. prolixus, especially when infected by T. rangeli. Examine how T. rangeli infection modulates R. prolixus cellular and humoral immunity and its impacts on insect microbiota. R. prolixus was fed on blood containing epimastigotes of T. rangeli, and infection was quantified in insect tissues. The gene expression of dorsal, cactus, relish, PGRP, and AMPs was examined in the midgut, fat body, and salivary glands by quantitative real-time PCR. Microbiota composition was analyzed using RT-q PCR targeting specific bacterial species. Hemocyte numbers and phenoloxidase activity were quantified to assess cellular immune responses. T. rangeli infection modulated triatomine immunity in midgut and hemocoel, activating the expression of the NF-kB gene dorsal, associated with the Toll pathway; increasing expression of the gene encoding PGRP receptor, a component involved in the IMD pathway, both in the intestine and fat body; repressing the expression of the relish transcription factor, mainly in salivary glands. Among the R. prolixus AMPs studied, T. rangeli infection repressed all AMP gene expression, other than defensin C which increased mRNA levels. The PO activity was enhanced in the hemolymph of infected insects. T. rangeli infection did not induce hemocyte number alterations compared to control insects. However, an increase in hemocyte microaggregation was detected in infected insects. R. prolixus recognizes T. rangeli infection and triggers humoral and cellular immune responses involving Toll pathway activation, defensin C synthesis, increased phenoloxidase activity, and enhanced hemocyte aggregation. On the other hand, T. rangeli infection suppressed some IMD pathway components, suggesting that, in R. prolixus, this pathway is involved in defensins A and B gene regulation. Importantly, these immune responses altered the bacterial microbiota composition, potentially favoring T. rangeli establishment in the insect vector.

Water quality and immunological response of banana shrimp (Fenneropenaeus merguiensis) co-cultured with green seaweed (Caulerpa lentillifera) in the laboratory

Co-culture of newly domesticated shrimp, F. merguiensis, and green seaweed, C. lentillifera, was conducted in six cement tanks to assess their impact on water quality and immunological response. Shrimp juveniles (14,3±0.3 mg) were stocked at a density of 50 shrimps/m2 and co-cultured with C. lentillifera at two initial stocking rates: A (0.1 kg/m2), B (0.2 kg/m2), and C (without seaweed) as a control treatment. All treatments were replicated twice, and the trial lasted eight weeks. The results of the experiment demonstrated that co-culturing F. merguiensis with C. lentillifera not only improves water quality, primarily nitrogen (TAN, NO2, NO3) and phospate (PO4-) compounds, but also on immunological parameters (THC, DHC, PA, and PO activity) assessed. Shrimp production indicators improve significantly (p&lt;0.05) after seaweed treatments. Furthermore, C. lentillifera grows at a pace of more than 10% per day and is suggested for co-culture with shrimp at a density of 0.1 - 0.2 kg/m2.

Rhynchophorus ferrugineus larvae: A novel source for combating broad-spectrum bacterial and fungal infections.

Antimicrobial resistance is a growing concern due to the growth of antibiotic-resistant microorganisms, which makes it difficult to treat infection. Due to its broad-spectrum antimicrobial properties against a diverse array of bacteria, both Gram-positive and Gram-negative bacteria, and fungi, Rhynchophorus ferrugineus larval antimicrobial peptides (AMPs) have demonstrated potential as antimicrobial agents for the treatment of microbial infections and prevention of antibiotic resistance. This study emphasizes the unexplored mechanisms of action of R. ferrugineus larvae against microorganisms. Among the most widely discussed mechanisms is the effect of AMPs in larvae in response to a threat or infection. Modulation of immune-related genes in the intestine and phagocytic capacity of its hemocytes may also affect the antimicrobial activity of R. ferrugineus larvae, with an increase in phenoloxidase activity possibly correlated with microbial clearance and survival rates of larvae. The safety and toxicity of R. ferrugineus larvae extracts, as well as their long-term efficacy, are also addressed in this paper. The implications of future research are explored in this paper, and it is certain that R. ferrugineus larvae have the potential to be developed as a broad-spectrum antimicrobial agent with proper investigation.

Selective strengthening of lipid metabolism and the rapid immune response of Ostrinia furnacalis larvae parasitized by Macrocentrus cingulum

The Macrocentrus cingulum is a vital endoparasitic wasp that parasites in Ostrinia furnacalis larvae. It has been widely utilized for biological control of corn borer. Although previous studies have explored how the wasps suppress the host's immunity, further research is required to determine the impact of the wasps on the host's lipid metabolism and activated immune response. In this study, high-throughput transcriptome sequencing, quantitative real-time PCR, and physiological and biochemical methods were used to investigate the balance between energy metabolism and immunity in parasitic systems. The results showed that specific genes linked to lipid metabolism and transportation were up-regulated in parasitized O. furnacalis larvae, including AKHR, AKH, apoLpIII, and FAS. Additionally, M. cingulum triggered immune responses in the parasitized larvae, leading to rapid recognition and the production of immunity effectors, such as Lysozyme and antimicrobial peptides, to protect against the invading wasps. The phenoloxidase (PO) activity was inhibited as a result of parasitization. Parasitism selectively promoted lipid metabolism and activated the immune recognition response, significantly up-regulated immune pattern recognition receptors (PRRs) and effector genes, but suppressed the PPO cascade response in O. furnacalis larvae. This study can shed light on lipid metabolism, immune response, and activating the immune recognition response for parasitoid and host co-evolution and provide insight into the biological control of O. furnacalis.

Soil Microbial and Enzymatic Properties in Luvisols as Affected by Different Types of Agricultural Land-Use Systems and Soil Depth

Determination of the microbial and enzymatic properties in soil is primarily concentrated on the surface layers of the soil profiles; however, it is well known that the transformation of soil organic matter also occurs in the deeper horizons of the soil profile. The aim of this study was to assess any changes in specific sets of enzyme activities and their associated physicochemical properties as affected by two different agricultural land-use systems and soil depth. Changes in the studied properties were determined across four Luvisol profiles in two agricultural land uses (arable land and vineyards). The enzyme activities associated with the transformation of C, N and P were analyzed. Additionally, the activity of some oxidoreductases and the fluorescein diacetate hydrolysis (FDAH) rate were also determined. Moreover, the content of the various forms of soil carbon, nitrogen, phosphorus (including microbial biomass C, N and P) and some other properties (pH, clay and silt content) were assessed. Agricultural land use significantly affected the microbial biomass content and as well as the studied enzyme activities. Most of the studied enzymes exhibited a higher activity in the grapevine (GV) profiles, which was followed by the winter wheat (WW) profiles; however, the largest variability occurred for the urease activity. There was no clear differentiation between the two studied land uses for the activity of nitrate reductase, dehydrogenases, acid phosphatase, or endo- and exo-cellulase. Irrespective of the plant being cultivated, the soil variables decreased significantly with increasing soil depth, wherein the greatest changes were observed between the surface and sub-surface soil horizons (I–II). The activity of some enzymes (e.g., the urease activity in WW profiles) decreased gradually across the soil profiles, while others were located almost solely within the surface layers (e.g., the nitrate reductase activity in the GV profiles as well as invertase in the WW profiles). The α-glucosidase activity did not exhibit any statistically significant changes along the analyzed profiles. The activity of phenol oxidase and peroxidase also revealed different trends along the studied profiles compared to the other enzymes and did not decrease gradually with depth. The microbial biomass of the C, N and P content was generally the highest in the upper horizons and gradually decreased with depth, wherein the largest decrease was observed between the surface and sub-surface horizon. The studied enzyme activities were more dependent on the soil carbon content compared to the other soil properties. And thus, in the C-rich horizons (C &gt; 4 g kg) for the surface and subsurface layers the enzyme activities were highly correlated with TOC, DOC and MBC content as compared to the deeper, C-low horizons (C &lt; 4 g kg). By examining how the microbial and enzymatic properties change across the soil profiles, it is possible to gain valuable insight into the long-term biogeochemical processes that are involved in soil fertility and in the health of agricultural ecosystems.

Dietary Tartaric Acid Improves Growth Performance, Gut Microbiota, Digestive Enzyme Activities, Hemolymph Immunity, Antioxidant Markers, and Disease Resistance against Vibrio parahaemolyticus in Pacific White Shrimp

Tartaric acid (TA) is an organic acid whose properties in aquaculture have not yet been comprehensively studied. In the current research, the effect of dietary TA on growth indices, gut microbiota, the level of digestive enzymes, antioxidant and immunological markers, and survival rate following immersion challenge with Vibrio parahaemolyticus (14 days) in Litopenaeus vannamei were investigated. To achieve this, 600 shrimp (3.26 ± 0.05 g) were tested with pellets supplemented with five distinct concentrations of TA including 0 (TA0), 2.5 (TA2.5), 5 (TA5), 7.5 (TA7.5), and 10 g/kg (TA10) for 56 days. The results showed that the growth performance, feed utilization, gut lactic acid bacteria (LAB) count, and activity of digestive enzymes were markedly elevated in the groups receiving diets incorporated with 5 and 7.5 g/kg of TA. The highest total hemocyte count (THC), hyaline cell (HC), and semi-granular cell (SGC) counts were detected in shrimp fed with the TA7.5 diet. Hemolymph immune responses including LYZ (lysozyme), alkaline phosphatase (AKP), acid phosphatase (ACP), and phenol oxidase (PO) activities were significantly enhanced in all TA-treated groups. Dietary TA7.5 significantly boosted all antioxidant enzymes. In addition, malondialdehyde (MDA) content illustrated a significant decrease in shrimp fed with diets supplemented with 2.5–10 g/kg TA when compared with specimens fed with TA0. The survival rate following the immersion challenge with Vibrio parahaemolyticus markedly increased in all shrimp treated with 2.5–10 g/kg TA compared to TA0, irrespective of the dosage. However, the dietary inclusion of TA7.5 resulted in the highest survival rate. Based on the outcomes, dietary TA, especially at the concentration of 7.5 g/kg, is proposed to promote the growth performance and immunological indicators of L. vannamei.

Serine protease mediates Ovomermis sinensis-inhibited host immune responses by inducing apoptosis: implications for successful parasitism and host mortality.

Mermithid nematodes are entomopathogens that parasitize and kill insect hosts and are used for biological control. It is widely believed that mermithid nematodes kill their host upon nematode emergence, unlike other parasites that depend on virulence factors. In this study, we disproved this theory by demonstrating that the mermithid nematode Ovomermis sinensis mediates host mortality by serine protease-induced apoptosis. Successful parasitism of O. sinensis increased with the infection rate, and the inhibition of host immunity by O. sinensis increased with the parasitic load. A serine protease was identified from the host hemolymph. This protease belongs to the trypsin-like serine protease family, which is an apoptosis-inducing serine protease. Specifically, Os-sp was highly expressed only during the parasitic stage and could be induced by host hemocytes and the fat body. Importantly, host immune effectors (melanization, phenoloxidase activity, and encapsulation) were suppressed by the recombinant protein rOs-sp that induced apoptosis of hemocytes and fat body in a dose-dependent manner, which contributes to host death. Serine protease mediates O. sinensis-inhibited host immune responses by inducing apoptosis that is lethal to the insect host. Our findings have broader implications for understanding the mechanism of successful parasitism and killing of host by nematodes. © 2023 Society of Chemical Industry.

Dietary β-Glucan Alleviates Antibiotic-Associated Side Effects by Increasing the Levels of Antioxidant Enzyme Activities and Modifying Intestinal Microbiota in Pacific White Shrimp (Litopenaeus vannamei).

Antibiotics and their secondary metabolites are commonly found in aquatic ecosystems, leading to the passive exposure of many aquatic animals to low doses of antibiotics, which can affect their health. However, there is limited information available on how to mitigate the side effects of antibiotics on normal aquatic animals. This study aimed to investigate the potential of dietary β-glucan to alleviate the side effects induced by antibiotics in Pacific white shrimp (Litopenaeus vannamei) (0.37 ± 0.02 g). A six-week feeding trial was conducted with four dietary treatments including a control, 1 g/kg β-glucan (β-glucan), 50 mg/kg oxytetracycline (OTC), and a combination of 50 mg/kg OTC and 1 g/kg β-glucan (Mix) groups. At the end of the trial, the growth performance, intestinal microbial composition, antioxidant capacity, and immune response of the shrimp were assessed. There were no significant differences in growth performance among the groups, but the condition factor of the shrimp in the Mix group was significantly decreased when compared to the control and β-glucan groups. The activities of hepatopancreas catalase (CAT) and serum phenol oxidase in the OTC group were significantly lower than those in the control group. On the other hand, the activities of hepatopancreas superoxide dismutase and CAT enzymes in the β-glucan group were significantly higher than those in the OTC group. The supplementation of β-glucan in combination with antibiotics significantly increased the CAT activity and bacteriolytic activity compared to the OTC and control groups, respectively. Moreover, an analysis of the intestinal microbiota revealed that the Observed_species estimator in the Mix group was significantly higher than that in the control group. Dietary antibiotics significantly increased the abundance of Actinobacteria at the phylum level, but the Mix group showed no significant difference. The supplementation of β-glucan in combination with antibiotics also significantly increased the relative abundance of Meridianimaribacter compared to the control group. Additionally, the synergistic influence of β-glucan with antibiotics increased the beta diversity of intestinal microbiotas. These findings suggest that the supplementation of β-glucan in combination with antibiotics on Pacific white shrimp can alleviate the low antioxidant capacity and immune response caused by antibiotics while enhancing the intestinal microbial composition. This provides a potential solution to mitigate the negative impacts of antibiotics in aquaculture.

Changes in the lipid composition of &lt;i&gt;Peltigera canina&lt;/i&gt; at an elevated temperature

Extremophile organisms can survive under extreme conditions through tolerance mechanisms. Such organisms include lichens, which are symbiotic associations of fungi and algae and/or cyanobacteria. Among other factors, the high stress tolerance of lichens can be attributed to their ability to synthesize a wide range of metabolites, including chemically diverse lipid compounds. Despite their obvious relevance, the biochemical mechanisms of stress tolerance in lichens that are mediated by changes in the lipid profile remain understudied. Peltigerous lichens constitute a separate division of lichens characterized by high growth rates and metabolic activity indices. Taking into account the temperate climate in which these lichens grow, it can be assumed that they may be highly sensitive to temperature fluctuations. These factors led to the choice of Peltigera canina, epigeic lichen, as the subject matter of this study. The present work examined stress-induced changes in the redox status of P. canina, as well as changes in its lipid composition at an elevated temperature (40 °С). The exposure of hydrated lichen thalli to an unfavorable temperature led to an increase in the level of hydrogen peroxide, phenoloxidase activity, and lipid peroxidation, which constitutes an important part of stress response in lichen. The stress-induced changes in the redox status of lichen thalli stimulated an increase in lipophilic antioxidant agents: a dramatic increase in the level of α-tocopherol and an increase in carotenoids, specifically β-carotene. Thus, the accumulation of lipophilic antioxidants constitutes an important part of the lipid-mediated stress response of P. canina to temperature elevation.

Serpin-4 Negatively Regulates Prophenoloxidase Activation and Antimicrobial Peptide Synthesis in the Silkworm, Bombyx mori.

The prophenoloxidase (PPO) activation and Toll antimicrobial peptide synthesis pathways are two critical immune responses in the insect immune system. The activation of these pathways is mediated by the cascade of serine proteases, which is negatively regulated by serpins. In this study, we identified a typical serpin, BmSerpin-4, in silkworms, whose expression was dramatically up-regulated in the fat body and hemocytes after bacterial infections. The pre-injection of recombinant BmSerpin-4 remarkably decreased the antibacterial activity of the hemolymph and the expression of the antimicrobial peptides (AMPs) gloverin-3, cecropin-D, cecropin-E, and moricin in the fat body under Micrococcus luteus and Yersinia pseudotuberculosis serotype O: 3 (YP III) infection. Meanwhile, the inhibition of systemic melanization, PO activity, and PPO activation by BmSerpin-4 was also observed. Hemolymph proteinase 1 (HP1), serine protease 2 (SP2), HP6, and SP21 were predicted as the candidate target serine proteases for BmSerpin-4 through the analysis of residues adjacent to the scissile bond and comparisons of orthologous genes in Manduca sexta. This suggests that HP1, SP2, HP6, and SP21 might be essential in the activation of the serine protease cascade in both the Toll and PPO pathways in silkworms. Our study provided a comprehensive characterization of BmSerpin-4 and clues for the further dissection of silkworm PPO and Toll activation signaling.

Biofortified Vermicompost Mediated Induced Resistance Response in Tomato against Fusarium oxysporum f. sp. lycopersici

Tomato (Solanum lycopersicum) is a widely cultivated and versatile fruit. Tomato production faces various constraints, both biotic and abiotic stresses. Fusarium wilt, caused by the soil-borne fungus Fusarium oxysporum f. sp. lycopersici, is a devastating disease that affects tomato plants worldwide, causing significant economic losses in tomato cultivation. Inthis study the potential use of biofortified vermicompost for wilt management was investigated. The biological control agents viz. Trichoderma harzianum, Pseudomonas fluorescens and Bacillus subtilis were used to fortified the vermicpompost. The study monitored various antioxidants, plant growth indicators, and disease rates across designated treatments at different intervals. The findings revealed substantial differences: tomato plants treated with biofortified vermicompost showed notable reductions in disease occurrence, improved growth, increased yields, and heightened antioxidant activity compared to the control. Among these treatments, the most remarkable outcomes were observed in plants treated with T. harzianum fortified vermicompost, exhibiting the highest recorded values across the parameters studied. Data revealed that the Tomato plants treated with vermicompost fortified with Trichoderma showed maximum root length (14.95 cm) after 15 days of sowing followed by T-2 (11.25 cm) and T-3 (9.85 cm). Maximum dry weight was observed in plants treated with vermicompost fortified with Trichoderma. Maximum PAL, PO and PPO activity was recorded in leaves from plant grown in vermicompost fortified with T. harzianum (T1) at 48 h followed by T2, T3 and T4. The findings revealed tomato plants treated with biofortified vermicompost showed notable reductions in disease occurrence, improved growth, increased yields, and higher accumulation of defense enzyme activity compared to the control.

The immune response of the whitefly Trialeurodes vaporariorum (Hemiptera: Aleyrodidae) when parasitized by Eretmocerus eremicus (Hymenoptera: Aphelinidae).

In insects, the innate immune system is subdivided into cellular and humoral defenses. When parasitoids attack insects, both reactions can be activated and notably, the phenoloxidase (PO) cascade and lytic activity are part of both cellular and humoral defenses. However, to our knowledge, no study has characterized any immune response of the whitefly Trialeurodes vaporariorum (Hemiptera: Aleyrodidae) to the attack of Eretmocerus eremicus (Hymenoptera: Aphelinidae). Therefore, the first objective of the present study was to determine whether whitefly nymphs recently parasitized by E. eremicus exhibit any immune response. For this, we estimate the level of prophenoloxidase (proPO), phenoloxidase (PO), and lytic activity by colorimetric assays. A second objective was to assess whether the observed whitefly immune response could be related to a previously reported preference of the predator Geocoris punctipes (Hemiptera: Lygaeidae) for non-parasitized nymphs. We therefore offered non-parasitized and recently parasitized nymphs to the predator. Our results show that parasitism of whitefly nymphs by E. eremicus induced a highly estimated level of proPO and PO, and a lower level of lytic activity. In addition, we found that G. punctipes did not show a preference for non-parasitized over recently parasitized nymphs. The nymphs of T. vaporariorum activated the PO pathway against E. eremicus; however, the increase in proPO and PO levels was traded-off with decreased lytic activity. In addition, the previously reported preference for non-parasitized nymphs was not seen in our experiments, indicating that the induced immune response did not affect predator behavior by G. punctipes.

Distinctive features of Zaprionus indianus hemocyte differentiation and function revealed by transcriptomic analysis.

Insects have specialized cell types that participate in the elimination of parasites, for instance, the lamellocytes of the broadly studied species Drosophila melanogaster. Other drosophilids, such as Drosophila ananassae and the invasive Zaprionus indianus, have multinucleated giant hemocytes, a syncytium of blood cells that participate in the encapsulation of the eggs or larvae of parasitoid wasps. These cells can be formed by the fusion of hemocytes in circulation or originate from the lymph gland. Their ultrastructure highly resembles that of the mammalian megakaryocytes. Morphological, protein expressional, and functional features of blood cells were revealed using epifluorescence and confocal microscopy. The respective hemocyte subpopulations were identified using monoclonal antibodies in indirect immunofluorescence assays. Fluorescein isothiocyanate (FITC)-labeled Escherichia coli bacteria were used in phagocytosis tests. Gene expression analysis was performed following mRNA sequencing of blood cells. D. ananassae and Z. indianus encapsulate foreign particles with the involvement of multinucleated giant hemocytes and mount a highly efficient immune response against parasitoid wasps. Morphological, protein expressional, and functional assays of Z. indianus blood cells suggested that these cells could be derived from large plasmatocytes, a unique cell type developing specifically after parasitoid wasp infection. Transcriptomic analysis of blood cells, isolated from naïve and wasp-infected Z. indianus larvae, revealed several differentially expressed genes involved in signal transduction, cell movements, encapsulation of foreign targets, energy production, and melanization, suggesting their role in the anti-parasitoid response. A large number of genes that encode proteins associated with coagulation and wound healing, such as phenoloxidase activity factor-like proteins, fibrinogen-related proteins, lectins, and proteins involved in the differentiation and function of platelets, were constitutively expressed. The remarkable ultrastructural similarities between giant hemocytes and mammalian megakaryocytes, and presence of platelets, and giant cell-derived anucleated fragments at wound sites hint at the involvement of this cell subpopulation in wound healing processes, in addition to participation in the encapsulation reaction. Our observations provide insights into the broad repertoire of blood cell functions required for efficient defense reactions to maintain the homeostasis of the organism. The analysis of the differentiation and function of multinucleated giant hemocytes gives an insight into the diversification of the immune mechanisms.

Effects of geniposide on innate immunity and antiviral activity of Scyllaparamamosain

In this study, we examined the impact of geniposide on the innate immunity of the mud crab Scylla paramamosain, specifically in relation to WSSV infection. Through the use of in vitro cell culture experiments, we assessed the effects of geniposide on various parameters of hemocyte activity in S. paramamosain. Our findings revealed that high doses of geniposide inhibited hemocyte growth, with an optimal dose of 100 mg/kg determined. Additionally, we observed that geniposide increased the total hemocyte counts in S. paramamosain following WSSV infection. Geniposide also enhanced the enzymatic activities in hemolymph following treatment. The enzymes affected by geniposide encompassed ACP (acid phosphatase), POD (phenol oxidase catalase), PO (phenoloxidase), SOD (superoxide dismutase), CAT (catalase), and LZM (lysozyme). Furthermore, the activities of ACP, POD, PO, and LZM were also observed to increase subsequent to infection with WSSV. Notably, geniposide was found to enhance the phagocytosis of V. alginolyticus within the hemocytes. Geniposide can reduce hemocyte apoptosis rates after treatment, as well as hemocytes infected with WSSV. Furthermore, geniposide treatment significantly up-regulated the expression level of Myosin, but expression levels of Astakine, C-type lectin (CTL), STAT, JAK, proPO, minichromosome maintenance protein (MCM7), caspase-3 and crustin were down-regulated in the hemocytes. Additionally, geniposide treatment inhibited WSSV replication in hemocytes of S. paramamosain, and enhanced the survival rates of mud crabs following WSSV infection. These experimental results provide evidence that geniposide can improve the immune response by regulating humoral immunity and cellular immunity, and enhance pathogen resistance in S. paramamosain.