The brown planthopper, Nilaparvata lugens, is a serious pest of rice crops throughout Asia and exhibits wing dimorphism, with brachypterous adults having reduced wings and macropterous adults possessing fully developed wings. To understand the reproductive strategies in two wing-morphs of this insect, the transcript encoding the major yolk protein precursor, vitellogenin (Vg), was cloned. The complete mRNA transcript was 6314 bp, which encodes a protein of 2063 residues including an 18-residue putative signal peptide. Analysis of the mature protein revealed two vitellogenin-N (or lipoprotein amino-terminal) domains near the N-terminus and a von Willebrand factor type D domain near the C-terminus. In addition, a highly conserved motif GL/ICG, and a number of cysteine residues were identified near the C-terminus. Northern blot analysis identified a ∼6.8 kb Vg gene transcript that was expressed exclusively in the adult female fat body cells. The expression profile revealed that the Vg gene starts to be expressed earlier (on day 3) in brachypters as compared to macropters where the mRNA transcript was observed on day 4. However, in both morphs, the amount of Vg mRNA increased to reach high levels during vitellogenic periods [from day 4 (in brachypters) and day 5 (in macropters) and onwards]. Reflecting the RNA transcription pattern, the Vg signal was detected by immunoblotting on day 3 and day 4 in haemolymph of brachypterous and macropterous females, respectively, and that was increased every day and remained high during the vitellogenic periods. Furthermore, the topical application of juvenile hormone (JH) III had up-regulated the Vg gene expression suggesting that the Vg gene is regulated by JH in N. lugens. In addition, it was demonstrated by Southern blot analysis that there exists a single copy of the gene in the N. lugens genome. A delayed trend in expression (of both the transcript and the protein) demonstrated by macropterous females in the present studies supports the hypothesis of prereproductive long distance migration in this wing-dimorphic species.

Nongenomic action of an insect steroid hormone, 20‐hydroxyecdysone (20E), has been implicated in several 20E‐dependent events including the programmed cell death of Bombyx anterior silk glands (ASGs), but no information is available for the mode of the action. We provide evidence for a putative membrane receptor located in the plasma membrane of the ASGs. Membrane fractions prepared from the ASGs exhibit high binding activity to [3H]ponasterone A (PonA). The membrane fractions did not contain conventional ecdysone receptor as revealed by Western blot analysis using antibody raised against Bombyx ecdysone receptor A (EcR‐A). The binding activity was not solubilized with 1 m NaCl or 0.05% (w/v) MEGA‐8, indicating that the binding sites were localized in the membrane. Differential solubilization and temperature‐induced phase separation in Triton X‐114 showed that the binding sites might be integrated membrane proteins. These results indicated that the binding sites are located in plasma membrane proteins, which we putatively referred to as membrane ecdysone receptor (mEcR). The mEcR exhibited saturable binding for [3H]PonA (Kd = 17.3 nm, Bmax = 0.82 pmol·mg−1 protein). Association and dissociation kinetics revealed that [3H]PonA associated with and dissociated from mEcR within minutes. The combined results support the existence of a plasmalemmal ecdysteroid receptor, which may act in concert with the conventional EcR in various 20E‐dependent developmental events.

In this study, 120 lactic acid bacterial strains from different fermented dairy products as well as 10 bacterial intestinal isolates were evaluated for in vitro and in vivo degradation of various food azo dyes. Of these isolates, lactic acid bacteria (LAB) strains 13 and 100 and the intestinal isolates Ent2 and Eco5 exhibited 96-98% degradation of the tested food azo dyes within 5-6 hours. High performance liquid chromatography mass spectra of sunset yellow (E110) and carmoisine (E122) anaerobic degradation products by the intestinal isolates showed that they were structurally related to toxic aromatic amines. For an in vivo study, eight groups of rats were treated for 90 days with either the food azo dyes or their degradation products. All groups were kept for a further 30 days as recovery period and then dissected at 120 days. Hematological, histopathological, and protein markers were assessed. Rats treated with either E110/E122 or their degradation products exhibited highly significant changes in red blood cell count, hemoglobin, hematocrit, mean corpuscular volume, mean corpuscular hemoglobin, mean corpuscular hemoglobin concentration, and white blood cell count. In addition, alanine and aspartate aminotransferases, amylase, total bilirubin, blood urea nitrogen, creatinine, glucose, total protein, and globulins were significantly increased. Furthermore, marked histopathological alterations in the liver, kidney, spleen, and small intestine were observed. Significant decreases in inflammation and a noticeable improvement in the liver, kidney, spleen, and small intestine of rats treated with LAB and food azo dyes simultaneously were observed. Finally, these results provide a reliable basis for not only a better understanding of the histological and biochemical effects of food additives, but also for early diagnostics. In addition, LAB strains 13 and 100 may play an important role as potential probiotics in food and dairy technology as a probiotic lactic acid starter.

Lysozymes are bacteriolytic peptides that are implicated in the insect nonspecific innate immune responses. In this study, a full-length cDNA encoding a c-type lysozyme from Schistocerca gregaria (SgLys) has been cloned and characterized from the fat body of immune-challenged 5(th) instar. The deduced mature lysozyme is 119 amino acid residues in length, has a calculated molecular mass of 13.4 kDa and an isoelectric point (Ip) of 9.2. SgLys showed high identities with other insect lysozymes, ranging from 41.5% to 93.3% by BLASTp search in NCBI. Eukaryotic in vitro expression of the SgLys ORF (rSgLys) with an apparent molecular mass of ∼16 kDa under SDS-PAGE is close to the calculated molecular weight of the full-length protein. rSgLys displayed growth inhibitory activity against Gram-negative and Gram-positive bacteria. 3D structure modeling of SgLys, based on comparison with that of silkworm lysozyme, and sequence comparison with the helix-loop-helix (α-hairpin) structure of hen egg white lysozyme (HEWL) were employed to interpret the antibacterial potencies. Phylogenetic alignments indicate that SgLys aligns well with insect c-type lysozymes that expressed principally in fat body and hemocytes and whose role has been defined as immune-related. Western blot analysis showed that SgLys expression was highest at 6-12 h post-bacterial challenge and subsequently decreased with time. Transcriptional profiles of SgLys were determined by semi-quantitative RT-PCR analysis. SgLys transcript was upregulated at the highest level in fat body, hemocytes, salivary gland, thoracic muscles, and epidermal tissue. It was expressed in all developmental stages from egg to adult. These data indicate that SgLys is a predominant acute-phase protein that is expressed and upregulated upon immune challenge.