Development of new and specific insect pest management methods is critical for overcoming pesticide resistance and collateral off-target killings. Gene silencing by feeding dsRNA to insects shows promise in this area. Here we described the use of a peptide nano-material, branched amphiphilic peptide capsules (BAPCs), that facilitates cellular uptake of dsRNA by insects through feeding. The insect diets included dsRNA with and without complexation with BAPCs. The selected insect species come from two different orders with different feeding mechanisms: Tribolium castaneum and Acyrthosiphon pisum. The gene transcripts tested (BiP and Armet) are part of the unfolded protein response (UPR) and suppressing their translation resulted in lethality. For Acyrthosiphon pisum, ingestion of BiP-dsRNA associated with BAPCs led to the premature death of the aphids (t=4-5days) compared to ingestion of the same amounts of free BiP-dsRNA (t=11-12days). Tribolium castaneum was effectively killed using a combination of BiP-dsRNA and Armet-dsRNA complexed with BAPCs; most dying as larvae or during eclosion (~75%). Feeding dsRNA alone resulted in fewer deaths (~30%). The results show that complexation of dsRNA with BAPCs enhanced the oral delivery of dsRNA over dsRNA alone.

Aphid saliva is predicted to contain proteins that modulate plant defenses and facilitate feeding. Armet is a well-characterized bifunctional protein in mammalian systems. Here we report a new role of Armet, namely as an effector protein in the pea aphid, Acyrthosiphon pisum. Pea aphid Armet's physical and chemical properties and its intracellular role are comparable to those reported for mammalian Armets. Uniquely, we detected Armet in aphid watery saliva and in the phloem sap of fava beans fed on by aphids. Armet's transcript level is several times higher in the salivary gland when aphids feed on bean plants than when they feed on an artificial diet. Knockdown of the Armet transcript by RNA interference disturbs aphid feeding behavior on fava beans measured by the electrical penetration graph technique and leads to a shortened life span. Inoculation of pea aphid Armet protein into tobacco leaves induced a transcriptional response that included pathogen-responsive genes. The data suggest that Armet is an effector protein mediating aphid-plant interactions.

The brain is one of the major targets of alcohol actions. Most of the excitatory synaptic transmission in the central nervous system is mediated by N-methyl-D-aspartate (NMDA) receptors. However, one of the most devastating effects of alcohol leads to brain shrinkage, loss of nerve cells at specific regions through a mechanism involving excitotoxicity, oxidative stress. Earlier studies have indicated that chronic exposure to ethanol both in vivo and in vitro, increases NR1 and NR2B gene expression and their polypeptide levels. The effect of alcohol and molecular changes on the regulatory process, which modulates NMDAR functions including factors altering transcription, translation, post-translational modifications, and protein expression, as well as those influencing their interactions with different regulatory proteins (downstream effectors) are incessantly increasing at the cellular level. Further, I discuss the various genetically altered mice approaches that have been used to study NMDA receptor subunits and their functional implication. In a recent countable review, epigenetic dimension (i.e., histone modification-induced chromatin remodeling and DNA methylation, in the process of alcohol related neuroadaptation) is one of the key molecular mechanisms in alcohol mediated NMDAR alteration. Here, I provide a recount on what has already been achieved, current trends and how the future research/studies of the NMDA receptor might lead to even greater engagement with many possible new insights into the neurobiology and treatment of alcoholism.

No abstract

Autophagy is a process that is necessary during starvation, as it replenishes metabolic precursors by eliminating damaged organelles. Autophagy is mediated by more than 35 autophagy-related (Atg) proteins that participate in the nucleation, elongation, and curving of the autophagosome membrane. In a pursuit to address the role of autophagy during development and immune resistance of the mealworm beetle, Tenebrio molitor, we screened ATG gene sequences from the whole-larva transcriptome database. We identified a homolog of ATG13 gene in T. molitor (designated as TmATG13) that comprises a cDNA of 1176 bp open reading frame (ORF) encoding a protein of 391 amino acids. Analyses of the structure-specific features of TmAtg13 showed an intrinsically disordered middle and C-terminal region that was rich in regulatory phosphorylation sites. The N-terminal Atg13 domain had a HORMA (Hop1, Rev7, and Mad2) fold containing amino acid residues conserved across the Atg13 insect orthologs. A quantitative reverse-transcription-polymerase chain reaction analysis revealed that TmATG13 was expressed ubiquitously during all developmental stages of the insect. TmATG13 mRNA expression was high in the fat body and gut of the larval and adult stages of the insect. The TmATG13 transcripts were expressed at a high level until 6 days of ovarian development, followed by a significant decline. Silencing of ATG13 transcripts in T. molitor larvae showed a reduced survivability of 39 and 38% in response to Escherichia coli and Staphylococcus aureus infection. Furthermore, the role of TmAtg13 in initiating autophagy as a part of the host cell autophagic complex of the host cells against the intracellular pathogen Listeria monocytogenes is currently under study and will be critical to unfold the structure-function relationships.