Agroecosystems are the habitat of pests and beneficial insects from different orders, which are exposed to agro-practices, especially treatments with chemicals. Insecticides are a wide group of chemicals used in agroecosystems that affect insect ecology and physiology in different ways. Among physiological components affected by insecticides, the immune system (IS) is an important one, enabling insects to resist against invading microorganisms and parasitoids thanks to the action of hemocytes and humoral components. So the determination of any immune alterations should be considered as a critical ‎issue in insecticide application within agroecosystems. ‎Insecticides of synthetic or natural origin, e.g. insect growth regulators (IGRs) and botanicals, are frequently cytotoxic and alter hemocyte morphology and number, impairing cellular-based immune responses in addition to humeral responses. Exposure of pollinators to neurotoxin insecticides like neonicotinoids may inhibit the immune-related transcription factor, NF-B, with a negative impact on the expression of antimicrobial peptides, melanization and clotting. In contrast, some IGRs may have enhancing effects on hemocyte spreading mainly plasmatocytes and cellular-based immune responses. Chemical insecticides have several impacts on the physiology of insects in which immune modulation‎ is one of the most important cases because any alteration may alter their ability to respond toward invading pathogens and directly their survival. This is more severe once pollinators are in contact with chemicals because of the presence of several pathogenic agents that directly influence their performance.

The hard clam (Meretrix meretrix) is a commercially and ecologically important benthic mollusk in South and Southeast Asia. Growth is one of the most important and complex traits affecting clam breeding. Therefore, identification of key growth factor genes and their association with growth traits are the primary prerequisites for in-depth study of the mechanisms of growth regulation and molecular marker-assisted selection of the hard clam. In the present study, we generated the full-length cDNA sequences of the growth-related genes BMP2 and BMP7 in M. meretrix (MmBMP2 and MmBMP7) and then investigated their gene expression patterns and associations with growth traits. The full-length cDNA of MmBMP2 was 2641 base pairs (bp), with a 1395 bp open reading frame (ORF) encoding 464 amino acids. The full-length MmBMP7 cDNA was 3161 bp, with a 1257 bp ORF encoding 418 amino acids. In adult clams, expression of MmBMP2 and MmBMP7 were significantly higher in the mantle than in the other five tested tissues (p < 0.05). Among the seven developmental stages of M. meretrix, expression of MmBMP2 was the highest in juveniles (p < 0.05), and expression of MmBMP7 was very low in 4-cell embryo and eyespot larva stages (p < 0.05). Two hundred and sixty-three individuals from two populations were screened for MmBMP2 and MmBMP7 polymorphisms, and single nucleotide polymorphisms (SNPs) associated with growth traits in MmBMP2 was found in both populations. Subsequent analysis revealed that two SNPs in MmBMP2 were shared between the populations. One was A726G, for which individuals with genotypes AG had significantly higher growth traits than those with genotype AA (p < 0.05). The other was A732T, for which individuals with genotype AT had significantly higher growth traits than those with genotype AA (p < 0.05). These results suggest that BMP2 markers may have potential value in molecular selective breeding to improve clam growth.

During phylogenesis different types of immunocytes such as amoebocytes and eleocytes have developed in earthworms to defend the host against microbial pathogens. Previously we applied a cell sorting-based approach to untangle the morphological and functional properties of these aforementioned coelomocyte subsets. In order to compare their constitutive gene expression patterns, cell-sorting was performed and followed by semiquantitative RT-PCR in the distinct, separated coelomocyte subpopulations of unmanipulated Eisenia andrei earthworms. We targeted a variety of genes with diverse functions ranging from pattern recognition through intracellular signaling to oxidative stress. Several immune-related genes (CCF, TLR, lumbricin, LuRP, MyD88) were only manifested in the amoebocytes. In contrast, other immune response genes (lysozyme, lysenin), lysosomal hydrolases (cathepsin L and cathepsin C) and cystatin B were expressed in both subpopulations. In addition, cell signaling molecules (MyD88, PKC1) and oxidative stress-related genes (Cu/ZnSOD, MnSOD) were mainly observed in amoebocytes, while other stress-related genes (Cd-metallothionein, catalase) were apparent in both subsets. We conclude that these characteristic differences of the molecular signatures manifest in the functional heterogeneity of distinct coelomocyte subtypes.

Insect parasitic factors of both maternal and embryonic origin allow the endoparasitoid progeny to elude the humoral and cellular immune system responses of their host. Endoparasitoid wasps of lepidopteran larval stages inject, along with venom and ovarian proteins, Polydnavirus particles acting in synergy with all other factors in host regulation for parasitism success. To date, the molecular mechanisms used by endoparasitoid to circumvent the host immune system are little known. Neverthless, several of these strategies are conserved through the wasp parasitoid species. Heliothis virescens is a noctuid moth, host of the endophagous parasitoid Toxoneuron nigriceps. The first observed effect of parasitism is immune system suppression, as direct consequence of the array of host regulation factors, both of embryonic and maternal origin. This review describes the contribution of all the parasitic components during alterations of the host immune response observed after oviposition by T. nigriceps.

Despite the low diversity and high variability at intra- and interspecific levels, gut microbiota of insect play important roles in digesting and absorbing nutrients, health and development, even in resistance and immunity. In this study, we investigate the composition and diversity of gut microbiota in the 5 th instar of silkworm larvae since the mount of ingested mulberry leaves of this stage is about 85% of the total amount. Intestinal contents were collected at 0, 12, 24, 48 and 72h in the 5 th instar. 32, 21, 29, 24, 14 phyla and 386, 163, 292, 196, 144 genera were detected respectively in the samples described above. In general, the dominated phyla in the larvae gut were Firmicutes, Cyanobacteria, Proteobacteria, Actinobacteria and Bacteroidetes; the dominated genera were Enterococcus, Staphylococcus, Arthrobacter, Pseudomonas, Lactobacillus, Bacteroides, Paenibacillus and Serratia, respectively. The range of phyla and genera was different and there were two peaks of microbial diversity at 0 and 24 h. Compared with the intestinal bacteria of these time points, there were unique bacteria and 56 common ones. In these bacteria, the abundance of Gram-positive bacteria including Enterococcus and Staphylococcus were the highest. Our results provided foundation and reference on the research of intestinal microorganisms and resistance breeding in silkworm.

The Ras family GTPase Rheb, a GTP-binding protein, binds specifically to the mTOR catalytic domain and induces activation of the mTOR catalytic function. Furthermore, Rheb is related to a stable modification of the configuration of mTORC1 that increases access of substrates to their binding site on the raptor polypeptide. In the present research, a cDNA of 898 bp for the Litopenaeus vannamei Rheb was cloned via rapid amplification of cDNA ends (RACE) technique. The complete cDNA sequence of Rheb contained an open reading frame (ORF) of 549 bp, which encoded a protein of 182 amino acids. The amino acid sequence of Rheb shared more than 60% similarity with other identified Rheb proteins. A Ras domain (from P3 to A169) was found in the amino acid sequence of Rheb that can react selectively and non-covalently with GTP. The mRNA transcripts of Rheb were consistently expressed in all the tested tissues, including muscle, gill, hepatopancreas, eyestalk, intestine and stomach. The mRNA expression profiles of Rheb in muscle after the stimulation with rapamycin were promoted, which further proved that Rheb protein could be a feedback regulator to mTOR signaling pathway. Furthermore, the results of the present study indicated that Rheb played an important role in the regulation of mTOR signaling pathway during the stimulation of dietary restriction, amino acid supplementation and rapamycin stimulation in shrimp.

Planarians in the Phylum Platyhelminthes occupy a peculiar phylogenetic position and have a strong regenerative capacity of their adult tissues, which has aroused general attention. Planarians are spontaneously exposed to various pathogens (microbes and harmful chemicals), but typically survive these challenges. Therefore, these animals can provide useful insights into the evolution of the innate immune system. This review mainly focuses on immune tissues (epidermis, pharynx, and intestine), immune cells (phagocytic reticular cells) and immune genes of planarians. In addition, we provide an overview of the critical proteins in the innate immune system - for example, pattern recognition receptors, complement system proteins, anti-microbial peptides and antioxidant enzymes. In particular, the effectors of the signaling pathways activated upon planarian infection are reviewed.

Before maintenance work could be carried out on the sewage system in the city of Montreal (Quebec, Canada), 5 billion litres of untreated wastewater had to be released directly into the St. Lawrence River over a five-day period in November 2015. The purpose of this study was to examine the toxicity of untreated wastewaters on quagga mussels. Water samples were collected at various points from the most densely populated downtown area and downstream points: 0 km, 5 km, 12 km, 16 km and 19 km. A river water sample was collected at the opposite shore as a reference site, and aquarium (dechlorinated tap) water was used for controls. Mussels were exposed for four days at 15 oC to these wastewaters, then examined for biotransformation (CYP1A1 and glutathione S-transferase activities), energy expenses (mitochondria activity and triglycerides), estrogenicity (alkali-labile phosphates) and damage (lipid peroxidation and DNA strand breaks). The data revealed that exposure to the released wastewaters produced changes to all the above biomarkers. CYP1A1 activity, DNA damage and triglyceride levels were the most responsive biomarkers for optimal site classification as determined by discriminant function analysis. CYP1A1 activity, lipid peroxidation and alkali-labile phosphate levels were significantly correlated with distance from downtown, suggesting that population density influenced more directly those effects. In conclusion, exposure to untreated wastewaters could lead to adverse toxic effects in quagga mussels. Mussels could be at risk from the release of untreated wastewaters events given that high-intensity precipitation could also result in the release of untreated wastewaters in these times of climate change.

Calreticulin (CRT) plays crucial roles in the regulation of Ca2+ homeostasis, immune responses and molecular chaperon. In this study, a new member of the CRT gene (denoted as AjCRT) was cloned and characterized from the sea cucumber Apostichopus japonicus. The full-length of the gene was of 3316 bp, which consisted of 204 bp 5’ untranslated region (UTR), 1870 bp of 3’-UTR and a putative 1242-bp open reading frame encoding a 48-kDa polypeptide (AjCRT) with a theoretical pI of 4.19. AjCRT had 59 % - 65 % sequence identity with CRTs from other species. It contained two CRT domains (residues 94 - 109 and 126 - 134) with a RING finger domain. AjCRT was ubiquitously expressed in all tissues examined, but was highly expressed in the coelomocytes. Temporal transcriptional levels in the coelomocytes revealed significant upregulation of AjCRT after the animal was challenged with Vibrio splendidus, reaching 4.97-fold the level of control at 4 h, but then decreased to 2.56-fold the level of control at 72 h. AjCRT knockdown decreased the expression level of the binding of Ca2+ to protein gene about 50 %. At the same time, intracellular concentration of Ca2+ also increased by 1.86-fold and 1.94-fold compared to that of the control. Taken together, the results suggested that AjCRT may be associated with the immune response against bacterial infection, probably through participating in the regulation of intracellular Ca2+ homeostasis in sea cucumber.

Numerous neuropeptides were studied in different invertebrate species, but the presence of most of them was evaluated only by an immunocytochemical approach using antibodies against the vertebrate homologues. As a consequence, several authors referred to the presence of neuropeptide-like molecules. In view of the availability of numerous wholly sequenced invertebrate genomes, here we reviewed the data on the gene sequence and the related structure of four neuropeptides (corticotrophin-releasing hormone, tachykinins, bombesin and insulin) in invertebrates, analyzing their functions in comparison to what reported in vertebrates.