Bivalent non-typhoidal Salmonella outer membrane vesicles immunized mice sera confer passive protection against gastroenteritis in a suckling mice model

Invasive non-typhoidal Salmonella (iNTS) serovars, especially Salmonella Typhimurium (ST) and Salmonella Enteritidis (SE), cause gastroenteritis worldwide. Due to the emergence of multi-drug resistance in iNTS, a broad-spectrum vaccine is urgently needed for the prevention of iNTS infection. Currently, there is no effective licensed vaccine against iNTS available in the market. We have formulated an outer membrane vesicles (OMVs) based bivalent immunogen as a vaccine candidate to generate broad-spectrum protective immunity against both recently circulating prevalent ST and SE. We have isolated OMVs from ST and SE and formulated the immunogen by mixing both OMVs (1:1 ratio). Three doses of bivalent immunogen significantly induced humoral immune responses against lipopolysaccharides (LPSs) and outer membrane proteins (OMPs) as well as a cell-mediated immune response in adult mice. We also observed that proteins of OMVs act as an adjuvant for generation of high levels of anti-LPS antibodies through T cell activation. We then characterized the one-day old suckling mice model for both ST and SE mediated gastroenteritis and used the model for a passive protection study. In the passive protection study, we found the passive transfer of bivalent OMVs immunized sera significantly reduced ST and SE mediated colonization and gastroenteritis symptoms in the colon of suckling mice compared to non-immunized sera recipients. The overall study demonstrated that OMVs based bivalent vaccine could generate broad-spectrum immunity against prevalent iNTS mediated gastroenteritis. This study also established the suckling mice model as a suitable animal model for vaccine study against iNTS mediated gastroenteritis.     

Aberrant antibody affinity selection in SHIP‐deficient B cells

The strength of the Ag receptor signal influences development and negative selection of B cells, and it might also affect B‐cell survival and selection in the GC. Here, we have used mice with B‐cell‐specific deletion of the 5′‐inositol phosphatase SHIP as a model to study affinity selection in cells that are hyperresponsive to Ag and cytokine receptor stimulation. In the absence of SHIP, B cells have lower thresholds for Ag‐ and interferon (IFN)‐induced activation, resulting in augmented negative selection in the BM and enhanced B‐cell maturation in the periphery. Despite a tendency to spontaneously downregulate surface IgM expression, SHIP deficiency does not alter anergy induction in response to soluble hen‐egg lysozyme Ag in the MDA4 transgenic model. SHIP‐deficient B cells spontaneously produce isotype‐switched antibodies; however, they are poor responders in immunization and infection models. While SHIP‐deficient B cells form GCs and undergo mutation, they are not properly selected for high‐affinity antibodies. These results illustrate the importance of negative regulation of B‐cell responses, as lower thresholds for B‐cell activation promote survival of low affinity and deleterious receptors to the detriment of optimal Ab affinity maturation.     

High Tregs and systemic IL-10 expressions linked to the absence of sheath antibodies in lymphatic filariasis: implications on the persistence of residual infection

The persistence of residual infection is one of the major factors in failure of the Global Programme to Eliminate Lymphatic Filariasis (GPELF). The present study aims to explore the status of sheath antibody and regulatory T cells (Tregs) known to play key roles in clearance of parasite and patent filarial infection, in individuals with residual infection after MDA. A total of 61 microfilaremic (Mf) individuals were followed up after at least 6 rounds of MDA. Infection status of subjects was assessed through the detection of Mf and circulating filarial antigen (CFA). Antibodies to Mf sheath were determined by immuno-peroxidase assay (IPA). The expression of Tregs was measured by a flow cytometer. IL-10 and IFN-γ were evaluated using the commercially available ELISA kit. The sheath antibody was present in subjects who have cleared both Mf and CFA and absent in individuals who were found to be Mf /CFA positive. Further individuals carrying infection have significantly high levels of Tregs and IL-10. A positive correlation was observed between Tregs, IL-10, and CFA in infected individuals. In contrast, a negative correlation was observed between IFN-γ and IL-10 in both infected and uninfected subjects. Our study reveals that the absence of a sheath antibody and a high level of Tregs and IL-10 are the hallmarks of the persistence of residual filarial infection.

     

Bio-nanoparticle assembly: a potent on-site biolarvicidal agent against mosquito vectors

Background: Vector-borne diseases such as malaria, dengue, yellow fever, encephalitis and filariasis are considered serious human health concerns in the field of medical entomology. Controlling the population of mosquito vectors is one of the best strategies for combating such vector-borne diseases. However, the use of synthetic insecticides for longer periods of time increases mosquito resistance to the insecticides. Recently, the search for new environmentally friendly and efficient insecticides has attracted major attention globally. With the evolution of material sciences, researchers have reported the effective control of such diseases using various sustainable resources. The present investigation demonstrates a potent on-site biolarvicidal agent against different mosquito vectors such as Aedes albopictus, Anopheles stephensi and Culex quinquefasciatus. Methods: Stable and photo-induced colloidal silver nanoparticles were generated via the surface functionalization of the root extract of Cyprus rotundas. Characterizations of the nanoparticles were performed using assorted techniques, such as UV-visible spectroscopy, FTIR spectroscopy, DLS and HRTEM. The bioefficacy of the synthesized nanoparticles was investigated against different species of mosquito larvae through the evaluation of their life history trait studies, fecundity and hatchability rate of the treated larvae. Histopathological and polymerase chain reaction-random amplified polymorphic DNA (RAPD) analyses of the treated larvae were also examined to establish the cellular damage. Results: The synthesized nanoparticles showed remarkable larvicidal activity against mosquito larvae in a very low concentration range (0.001–1.00) mg L⁻¹. The histopathological study confirmed that the present nanoparticles could easily enter the cuticle membrane of mosquito larvae and subsequently obliterate their complete intestinal system. Furthermore, RAPD analysis of the treated larvae could assess the damage of the DNA banding pattern. Conclusion: The present work demonstrates a potent biolarvicidal agent using sustainable bioresources of the aqueous Cyprus rotundas root extract. The results showed that the synthesized nanoparticles were stable under different physiological conditions such as temperature and photo-induced oxidation. The effectiveness of these materials against mosquito larvae was quantified at very low dose concentrations. The present biolarvicidal agent can be considered as an environmentally benign material to control the mosquito vectors with an immense potential for on-site field applications.

The present work demonstrates a potent and stable biolarvicidal agent using sustainable bioresources. The synthesized nanomaterials can control the mosquito vectors at a very low concentration range (0.01–1.00 mg L⁻¹) for on-site field applications.     

Telomerase inhibition by siRNA causes senescence and apoptosis in Barrett's adenocarcinoma cells: mechanism and therapeutic potential

Background  

In cancer cells, telomerase induction helps maintain telomere length and thereby bypasses senescence and provides enhanced replicative potential. Chemical inhibitors of telomerase have been shown to reactivate telomere shortening and cause replicative senescence and apoptotic cell death of tumor cells while having little or no effect on normal diploid cells.     

From the Cover: A fluorophore ligase for site-specific protein labeling inside living cells

Biological microscopy would benefit from smaller alternatives to green fluorescent protein for imaging specific proteins in living cells. Here we introduce PRIME (PRobe Incorporation Mediated by Enzymes), a method for fluorescent labeling of peptide-fused recombinant proteins in living cells with high specificity. PRIME uses an engineered fluorophore ligase, which is derived from the natural Escherichia coli enzyme lipoic acid ligase (LplA). Through structure-guided mutagenesis, we created a mutant ligase capable of recognizing a 7-hydroxycoumarin substrate and catalyzing its covalent conjugation to a transposable 13-amino acid peptide called LAP (LplA Acceptor Peptide). We showed that this fluorophore ligation occurs in cells in 10 min and that it is highly specific for LAP fusion proteins over all endogenous mammalian proteins. By genetically targeting the PRIME ligase to specific subcellular compartments, we were able to selectively label spatially distinct subsets of proteins, such as the surface pool of neurexin and the nuclear pool of actin.     

Degradation Dynamics of Flubendiamide in Different Types of Soils

Residual dynamics of flubendiamide in three different types of soils were investigated under laboratory condition. Flubendiamide was applied at 5 and 10 μg g⁻¹ for each soil and samples drawn periodically were analyzed on HPLC. The results showed that the degradation of flubendiamide in soils were followed first-order kinetics and its average half-lives in three kinds of soils were ranged from 37.62 to 60.21 days. The persistence of flubendiamide in soils significantly increased in the order of coastal soil > red and lateritic soil > new alluvial.     

Odontotrichodysplasia: A Case Report with a Review of Conditions Combining Ectodermal Dysplasia (Subgroup 1–2) with Skin Manifestations

We report a 5-year-old girl with partial anodontia, hypotrichosis, hyperpigmentation of the skin, absence of pilosebaceous structures, and long thin fingers. There has as yet been, to the best of our knowledge, no report of such a combination of features. A review of conditions combining ectodermal dysplasia (subgroup 1–2) with skin manifestations is presented.     

Establishment of the major compatibility complex-dependent development of CD4+ and CD8+ T cells by the Cbl family proteins

Casitas B cell lymphoma (Cbl) proteins are negative regulators for T cell antigen receptor (TCR) signaling. Their role in thymocyte development remains unclear. Here we show that simultaneous inactivation of c-Cbl and Cbl-b in thymocytes enhanced thymic negative selection and altered the ratio of CD4(+) and CD8(+) T cells. Strikingly, the mutant thymocytes developed into CD4(+)- and CD8(+)-lineage T cells independent of the major histocompatibility complex (MHC), indicating that the CD4(+)- and CD8(+)-lineage development programs are constitutively active in the absence of c-Cbl and Cbl-b. The mutant double-positive (DP) thymocytes exhibited spontaneous hyperactivation of nuclear factor-kappa B (NF-kappaB). Additionally, they failed to downregulate the pre-TCR and pre-TCR signaling. Thus, our data indicate that Cbl proteins play a critical role in establishing the MHC-dependent CD4(+) and CD8(+) T cell development programs. They likely do so by suppressing MHC-independent NF-kappaB activation, possibly through downmodulating pre-TCR signaling in DP thymocytes.