Kairomones ofheliothis armigera andcorcyra cephalonica and their influence on the parasitic potential oftrichogramma chilonis (Trichogrammatidae: hymenoptera)

Kairomones from moth scales tend to influence the parasitic potential byTrichogramma chilonis Ishii. Hexatriacontane, pentacosane, heptadecane, docosane and 2, 6, l0-dodecatrienal-3, 7, 11-trimethyl were identified from the active moth scale extract ofHeliothis armigera Hubner (its natural host) andCorcyra cephalonica Stainton (a laboratory host). The significance of an array of compounds from moth scales with kairomonal activity for manipulating entomophagous insects in biological control programmes is discussed.     

Crystal structure of uncleaved L-aspartate-alpha-decarboxylase from Mycobacterium tuberculosis

L-aspartate-alpha-decarboxylase (ADC) is a critical regulatory enzyme in the pantothenate biosynthetic pathway and belongs to a small class of self-cleaving and pyruvoyl-dependent amino acid decarboxylases. The expression level of ADC in Mycobacterium tuberculosis (Mtb) was confirmed by cDNA analysis, immunoblotting with an anti-ADC polyclonal antibody using whole cell lysate and immunoelectron microscopy. The recombinant ADC proenzyme from Mycobacterium tuberculosis (MtbADC) was overexpressed in E. coli and the protein structure was determined at 2.99 A resolution. The proteins fold into the double-psi beta-barrel structure. The subunits of the two tetramers (there are eight ADC molecules in the asymmetric unit) form pseudo fourfold rotational symmetry, similar to the E. coli ADC proenzyme structure. As pantothenate is synthesized in microorganisms, plants, and fungi but not in animals, structure elucidation of Mtb ADC is of substantial interest for structure-based drug development.     

Evaluation of GABA Production and Probiotic Activities of Enterococcus faecium BS5

Probiotics and Antimicrobial Proteins - Gamma-aminobutyric acid (GABA) is a principal inhibitory neurotransmitter in the central nervous system and is produced by irreversible decarboxylation of...     

The Interaction of the Cellular Export Adaptor Protein Aly/REF with ICP27 Contributes to the Efficiency of Herpes Simplex Virus 1 mRNA Export

Herpes simplex virus 1 (HSV-1) protein ICP27 enables viral mRNA export by accessing the cellular mRNA export receptor TAP/NXF, which guides mRNA through the nuclear pore complex. ICP27 binds viral mRNAs and interacts with TAP/NXF, providing a link to the cellular mRNA export pathway. ICP27 also interacts with the mRNA export adaptor protein Aly/REF, which binds cellular mRNAs and also interacts with TAP/NXF. Studies using small interfering RNA (siRNA) knockdown indicated that Aly/REF is not required for cellular mRNA export, and similar knockdown studies during HSV-1 infection led us to conclude that Aly/REF may be dispensable for viral RNA export. Recently, the structural basis of the interaction of ICP27 with Aly/REF was elucidated at atomic resolution, and it was shown that three ICP27 residues, W105, R107, and L108, interface with the RNA recognition motif (RRM) domain of Aly/REF. Here, to determine the role the interaction of ICP27 and Aly/REF plays during infection, these residues were mutated to alanine, and a recombinant virus, WRL-A, was constructed. Virus production was reduced about 10-fold during WRL-A infection, and export of ICP27 protein and most viral mRNAs was less efficient. We conclude that interaction of ICP27 with Aly/REF contributes to efficient viral mRNA export.     

Genome Sequencing Unveils a Novel Sea Enterotoxin-Carrying PVL Phage in Staphylococcus aureus ST772 from India

Staphylococcus aureus is a major human pathogen, first recognized as a leading cause of hospital-acquired infections. Community-associated S. aureus (CA-SA) pose a greater threat due to increase in severity of infection and disease among children and healthy adults. CA-SA strains in India are genetically diverse, among which is the sequence type (ST) 772, which has now spread to Australia, Europe and Japan. Towards understanding the genetic characteristics of ST772, we obtained draft genome sequences of five relevant clinical isolates and studied the properties of their PVL-carrying prophages, whose presence is a defining hallmark of CA-SA. We show that this is a novel prophage, which carries the structural genes of the hlb-carrying prophage and includes the sea enterotoxin. This architecture probably emerged early within the ST772 lineage, at least in India. The sea gene, unique to ST772 PVL, despite having promoter sequence characteristics typical of low expression, appears to be highly expressed during early phase of growth in laboratory conditions. We speculate that this might be a consequence of its novel sequence context. The crippled nature of the hlb-converting prophage in ST772 suggests that widespread mobility of the sea enterotoxin might be a selective force behind its ‘transfer’ to the PVL prophage. Wild type ST772 strains induced strong proliferative responses as well as high cytotoxic activity against neutrophils, likely mediated by superantigen SEA and the PVL toxin respectively. Both proliferation and cytotoxicity were markedly reduced in a cured ST772 strain indicating the impact of the phage on virulence. The presence of SEA alongside the genes for the immune system-modulating PVL toxin may contribute to the success and virulence of ST772.     

How Do Urban Indian Private Practitioners Diagnose and Treat Tuberculosis? A Cross-Sectional Study in Chennai

Setting

Private practitioners are frequently the first point of healthcare contact for patients with tuberculosis (TB) in India. Inappropriate TB management practices among private practitioners may contribute to delayed TB diagnosis and generate drug resistance. However, these practices are not well understood. We evaluated diagnostic and treatment practices for active TB and benchmarked practices against International Standards for TB Care (ISTC) among private medical practitioners in Chennai.

Design

A cross-sectional survey of 228 practitioners practicing in the private sector from January 2014 to February 2015 in Chennai city who saw at least one TB patient in the previous year. Practitioners were randomly selected from both the general community and a list of practitioners who referred patients to a public-private mix program for TB treatment in Chennai. Practitioners were interviewed using standardized questionnaires.

Results

Among 228 private practitioners, a median of 12 (IQR 4–28) patients with TB were seen per year. Of 10 ISTC standards evaluated, the median of standards adhered to was 4.0 (IQR 3.0–6.0). Chest physicians reported greater median ISTC adherence than other MD and MS practitioners (score 7.0 vs. 4.0, P<0.001), or MBBS practitioners (score 7.0 vs. 4.0, P<0.001). Only 52% of all practitioners sent >5% of patients with cough for TB testing, 83% used smear microscopy for diagnosis, 33% monitored treatment response, and 22% notified TB cases to authorities. Of 228 practitioners, 68 reported referring all patients with new pulmonary TB for treatment, while 160 listed 27 different regimens; 78% (125/160) prescribed a regimen classified as consistent with ISTC. Appropriate treatment practices differed significantly between chest physicians and other MD and MS practitioners (54% vs. 87%, P<0.001).

Conclusion

TB management practices in India’s urban private sector are heterogeneous and often suboptimal. Private providers must be better engaged to improve diagnostic capacity and decrease TB transmission in the community.     

Key players in regulatory RNA realm of bacteria

Precise regulation of gene expression is crucial for living cells to adapt for survival in diverse environmental conditions. Among the common cellular regulatory mechanisms, RNA-based regulators play a key role in all domains of life. Discovery of regulatory RNAs have made a paradigm shift in molecular biology as many regulatory functions of RNA have been identified beyond its canonical roles as messenger, ribosomal and transfer RNA. In the complex regulatory RNA network, riboswitches, small RNAs, and RNA thermometers can be identified as some of the key players. Herein, we review the discovery, mechanism, and potential therapeutic use of these classes of regulatory RNAs mainly found in bacteria. Being highly adaptive organisms that inhabit a broad range of ecological niches, bacteria have adopted tight and rapid-responding gene regulation mechanisms. This review aims to highlight how bacteria utilize versatile RNA structures and sequences to build a sophisticated gene regulation network.     

Identification and Biochemical Studies on Novel Non-Nucleoside Inhibitors of the Enzyme Adenosine Kinase

The enzyme adenosine kinase (AK) plays a key role in the regulation of intracellular and extracellular concentration of adenosine (Ado), which exhibits potent hormonal activity in cardiovascular, nervous and immune systems. In view of the pharmacological effects of Ado, there is much interest in identifying inhibitors of AK, which can augment its tissue-protective effects. In this study, we have screened 1040 compounds from a chemical library of putative kinase inhibitors for their effect on purified human recombinant AK. These studies have identified 8 novel, non-nucleoside AK inhibitors. Four of these compounds (viz. 2-tert-butyl-4H-benzo[1,2,4]thiadiazine-3-thione (2759–0749); N-(5,6-diphenyl-furo[2,3-d]pyrimidin-4-yl)-propionamide (3998–0118); 3-[5,6-Bis-(4-methoxy-phenyl)-furo[2,3-d]pyrimidin-4-ylamino]-propan-1-ol (4072–2732); and 2-[2-(3,4-dihydroxy-phenyl)-5-phenyl-1H-imidazol-4-yl]-fluoren-9-one (8008–6198)), which inhibited human AK in a concentration-dependent manner in a low micromolar range (IC₅₀ = 0.38 ∼ 1.98 μM) were further studied. Kinetic and structural studies on these compounds provide evidence that inhibition of AK by these compounds was competitive with respect to Ado and non-competitive for ATP. All of these compounds also inhibited uptake of Ado and its metabolism in cultured mammalian cells at comparable concentrations indicating their efficient cellular penetrability. These AK inhibitors, whose chemical structures differ significantly from all previously known inhibitors, provide useful lead compounds for identification of more potent but less toxic AK inhibitors that may prove useful for therapeutic purposes.     

2,4,6-Triphenylaniline nanoemulsion formulation,optimization, and its application in type 2 diabetes mellitus

The secondary metabolite 2,4,6-triphenylaniline (TPA) was isolated from an endophytic fungi Alternaria longipes strain VITN14G of mangrove plant Avicennia officinalis, that exhibited satisfactory in vitro antidiabetic activity for type 2 diabetes mellitus (T2DM). The TPA was encapsulated using nanoemulsion (NE) to overcome the problem of stability and permeability to increase its therapeutic applications. Response surface methodology (RSM) was used for the optimization of the variables given, such as hydrodynamic diameter, surface charge, and polydispersity index (PDI). TPA was encapsulated using an optimized ratio of olive oil and tween 80 (2:1) significantly affected the response variables including particle size (124.8 nm), ζ potential (−46.0 mV), and PDI (0.396), and the encapsulation efficiency was found to be 95.93%. The TPA-loaded NE after MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) analysis showed nontoxic effects on L929 normal cell lines (areolar and adipose subcutaneous connective tissue of Mus musculus) with a viable percentage of 92%. In vitro release study revealed the slow and sustained release of the TPA over 48 hrs from NE under the Fickian diffusion mechanism and followed the Higuchi model for release kinetics. Further, the percentage of α-glucosidase and α-amylase inhibition rate of TPA-loaded NE was found to be 78.5 and 43.42%, respectively. The present study, therefore, can aid in the development of a novel drug delivery system as a therapeutic approach to T2DM.     

Identification of an allosteric binding site for Zn2+ on the beta2 adrenergic receptor

The activity of G protein-coupled receptors (GPCRs) can be modulated by a diverse spectrum of drugs ranging from full agonists to partial agonists, antagonists, and inverse agonists. The vast majority of these ligands compete with native ligands for binding to orthosteric binding sites. Allosteric ligands have also been described for a number of GPCRs. However, little is known about the mechanism by which these ligands modulate the affinity of receptors for orthosteric ligands. We have previously reported that Zn(II) acts as a positive allosteric modulator of the beta(2)-adrenergic receptor (beta(2)AR). To identify the Zn(2+) binding site responsible for the enhancement of agonist affinity in the beta(2)AR, we mutated histidines located in hydrophilic sequences bridging the seven transmembrane domains. Mutation of His-269 abolished the effect of Zn(2+) on agonist affinity. Mutations of other histidines had no effect on agonist affinity. Further mutagenesis of residues adjacent to His-269 demonstrated that Cys-265 and Glu-225 are also required to achieve the full allosteric effect of Zn(2+) on agonist binding. Our results suggest that bridging of the cytoplasmic extensions of TM5 and TM6 by Zn(2+) facilitates agonist binding. These results are in agreement with recent biophysical studies demonstrating that agonist binding leads to movement of TM6 relative to TM5.