Nickel (II) Complexes of Histidyl-Peptides as Fenton-Reaction Catalysts

Addition of histidyl-peptides containing the glycyl-glycyl-L-histidyl sequence stimulated the catalysis of Ni(II) hydrogen peroxide reduction. Maximum bleaching of murexide or nitrosodimethylaniline was obtained with glycyl-glycyl-L-histidine. A decrease in the bleaching rates was observed upon addition of SOD or hydroxyl radical scavengers, showing that the hydrogen peroxide/Ni(II)/glycyl-glycyl-L-histidine system generated superoxide anions as well as hydroxyl radicals. In contrast, addition of glycyl-glycyl-L-histidine inhibited the Cu(II) hydrogen peroxide reduction.

When peptides or proteins were exposed to oxygen radicals produced by Ni(II)/glycyl-glycyl-L-histidine catalysis of hydrogen peroxide reduction, the observed effects were similar to those produced by oxygen radicals generated by water radiolysis or by Fe(II) or Cu(II) mediated Fenton-reactions: hydroxylation of phenylalanine, interchange of disulfides, destruction of tryptophans and dityrosine formation.     

Alcohol and Tobacco Increases Risk of High Risk HPV Infection in Head and Neck Cancer Patients: Study from North-East Region of India

Background

Human papilloma virus (HPV) associated Head and Neck Cancers (HNCs) have generated significant amount of research interest in recent times. Due to high incidence of HNCs and lack of sufficient data on high-risk HPV (hr-HPV) infection from North -East region of India, this study was conceived to investigate hr-HPV infection, its types and its association with life style habits such as tobacco, alcohol consumption etc.

Methods

A total of one hundred and six primary HNC tumor biopsy specimens were collected. These samples were analyzed for hr-HPV DNA (13 HPV types) using hybrid capture 2 (HC2) assay and genotyping was done by E6 nested multiplex PCR (NMPCR).

Results

The presence of hr-HPV was confirmed in 31.13% (n = 33) and 24.52% (n = 26) of the HNC patients by nested multiplex PCR (NMPCR) and HC2 assay respectively. Among hr-HPV positive cases, out of thirteen hr- HPV types analyzed, only two prevalent genotypes, HPV-16 (81.81%) followed by HPV-18 (18.18%) were found. Significant association was observed between hr-HPV infection with alcohol consumption (p <0.001) and tobacco chewing (p = 0.02) in HNC cases. Compared to HPV-18 infection the HPV-16 was found to be significantly associated with tobacco chewing (p = 0.02) habit.

Conclusions

Our study demonstrated that tobacco chewing and alcohol consumption may act as risk factors for hr-HPV infection in HNCs from the North-East region of India. This was the first study from North-East India which also assessed the clinical applicability of HC2 assay in HNC patient specimens. We suggest that alcohol, tobacco and hr- HPV infection act synergistically or complement each other in the process of HNC development and progression in the present study population.     

Comprehensive survey and geometric classification of base triples in RNA structures

Base triples are recurrent clusters of three RNA nucleobases interacting edge-to-edge by hydrogen bonding. We find that the central base in almost all triples forms base pairs with the other two bases of the triple, providing a natural way to geometrically classify base triples. Given 12 geometric base pair families defined by the Leontis-Westhof nomenclature, combinatoric enumeration predicts 108 potential geometric base triple families. We searched representative atomic-resolution RNA 3D structures and found instances of 68 of the 108 predicted base triple families. Model building suggests that some of the remaining 40 families may be unlikely to form for steric reasons. We developed an on-line resource that provides exemplars of all base triples observed in the structure database and models for unobserved, predicted triples, grouped by triple family, as well as by three-base combination (http://rna.bgsu.edu/Triples). The classification helps to identify recurrent triple motifs that can substitute for each other while conserving RNA 3D structure, with applications in RNA 3D structure prediction and analysis of RNA sequence evolution.     

Alkaline Phosphatase Activity in Skin, as Shown by Staining En Bloc1

A modification of Gomori's method for alkaline phosphatase was applied to 5-7 mm cubes of fresh, unfixed human skin. Exposure to the substrate of buffered Na-β·glycerophosphate was varied from 8-36 hr, to the 2% Co(NO₃)₃, 2-12 hr; and to ammonium sulfide (containing approximately 1% NH₃), 1-2 hr. Optimum timing for these treatments were found to be 24, 4 and 1 hr, respectively. After staining, blocks were embedded in paraffin and serial sections were made. In such small blocks, the staining was uniform throughout the block. Alkaline phosphatase activity was seen in the walls of the subepidermal and periappendageal capillaries, as well as in the eccrine sweat glands, and did not differ from that seen in stained frozen sections. In particular, there was no loss of specificity and no diffusion of the enzyme.     

Bioactive Compounds from Marine Bacteria and Fungi

Marine bacteria and fungi are of considerable importance as new promising sources of a huge number of biologically active products. Some of these marine species live in a stressful habitat, under cold, lightless and high pressure conditions. Surprisingly, a large number of species with high diversity survive under such conditions and produce fascinating and structurally complex natural products. Up till now, only a small number of microorganisms have been investigated for bioactive metabolites, yet a huge number of active substances with some of them featuring unique structural skeletons have been isolated. This review covers new biologically active natural products published recently (2007–09) and highlights the chemical potential of marine microorganisms, with focus on bioactive products as well as on their mechanisms of action.     

Purification and Characterization of Benzonitrilases from Arthrobacter sp. Strain J-1

We found two kinds of benzonitrilases, designated benzonitrilases A and B, in a cell extract of Arthrobacter sp. strain J-1 grown on benzonitrile as a sole carbon and nitrogen source. Benzonitrilases A and B were purified approximately 409-fold and 38-fold, respectively. Purified benzonitrilase A appeared to be homogeneous according to the criteria of polyacrylamide gel electrophoresis. Both the enzymes hydrolyzed benzonitrile to benzoic acid and ammonia without forming benzamide as an intermediate. The molecular weights of benzonitrilases A and B were found to be 30,000 and 23,000, respectively. The subunit molecular weight of benzonitrilase A was the same as its molecular weight. The isoelectric points of benzonitrilases A and B were 4.95 and 4.80, respectively. The optimum temperature and pH, respectively, for benzonitrilase A were 40°C and 8.5, and those for benzonitrilase B were 30°C and 7.5. The K_m values for benzonitrilases A and B were 6.7 mM and 4.5 mM, respectively. Both the enzymes degraded p-tolunitrile, 4-cyanopyridine, and p-chlorobenzonitrile, but they did not attack aliphatic nitriles or amides. Both the enzymes were inhibited by thiol reagents.     

Burkholderia cenocepacia Type VI Secretion System Mediates Escape of Type II Secreted Proteins into the Cytoplasm of Infected Macrophages

Burkholderia cenocepacia is an opportunistic pathogen that survives intracellularly in macrophages and causes serious respiratory infections in patients with cystic fibrosis. We have previously shown that bacterial survival occurs in bacteria-containing membrane vacuoles (BcCVs) resembling arrested autophagosomes. Intracellular bacteria stimulate IL-1β secretion in a caspase-1-dependent manner and induce dramatic changes to the actin cytoskeleton and the assembly of the NADPH oxidase complex onto the BcCV membrane. A Type 6 secretion system (T6SS) is required for these phenotypes but surprisingly it is not required for the maturation arrest of the BcCV. Here, we show that macrophages infected with B. cenocepacia employ the NLRP3 inflammasome to induce IL-1β secretion and pyroptosis. Moreover, IL-1β secretion by B. cenocepacia-infected macrophages is suppressed in deletion mutants unable to produce functional Type VI, Type IV, and Type 2 secretion systems (SS). We provide evidence that the T6SS mediates the disruption of the BcCV membrane, which allows the escape of proteins secreted by the T2SS into the macrophage cytoplasm. This was demonstrated by the activity of fusion derivatives of the T2SS-secreted metalloproteases ZmpA and ZmpB with adenylcyclase. Supporting this notion, ZmpA and ZmpB are required for efficient IL-1β secretion in a T6SS dependent manner. ZmpA and ZmpB are also required for the maturation arrest of the BcCVs and bacterial intra-macrophage survival in a T6SS-independent fashion. Our results uncover a novel mechanism for inflammasome activation that involves cooperation between two bacterial secretory pathways, and an unanticipated role for T2SS-secreted proteins in intracellular bacterial survival.     

Cadmium Removal by Lemna minor and Spirodela polyrhiza

The present study investigates the ability of two genus of duckweed (Lemna minor and Spirodela polyrhiza) to phytoremediate cadmium from aqueous solution. Duckweed was exposed to six different cadmium concentrations, such as, 0.5, 1.0, 1.5, 2.0, 2.5, and 3.0 mg/L and the experiment was continued for 22 days. Water samples were collected periodically for estimation of residual cadmium content in aqueous solution. At the end of treatment period plant samples were collected and accumulated cadmium content was measured. Cadmium toxicity was observed through relative growth factor and changes in chlorophyll content. Experimental results showed that Lemna minor and Spirodela polyrhiza were capable of removing 42–78% and 52–75% cadmium from media depending upon initial cadmium concentrations. Cadmium was removed following pseudo second order kinetic model. Maximum cadmium accumulation in Lemna minor was 4734.56 mg/kg at 2 mg/L initial cadmium concentration and 7711.00 mg/kg in Spirodela polyrhiza at 3 mg/L initial cadmium concentration at the end of treatment period. Conversely in both cases maximum bio-concentration factor obtained at lowest initial cadmium concentrations, i.e., 0.5 mg/L, were 3295.61 and 4752.00 for Lemna minor and Spirodela polyrhiza respectively. The present study revealed that both Lemna minor and Spirodela polyrhiza was potential cadmium accumulator.     

The natural antiviral and immune stimulant effects of Allium cepa essential oil onion extract against virulent Newcastle disease virus

Fifty broiler chicks were divided into five groups to study the antiviral and immune-stimulant effect of Allium cepa essential oils (ACEO). The effect of Allium cepa essential oils administration single or combined with NVD vaccine in broilers, more than one parameter was studied in this study i.e., the clinical symptoms that appeared on the chicks after the experimental infection with velogenic Newcastle disease virus, postmortem lesions, pathological lesions scoring, mortality rate (MR), and viral shedding, birds immunity was assessed by HI test and protection percent post-challenge with vNDV. Our result showed that mild clinical signs, lesion scoring, decreased viral shedding in ACEO treated groups 3 (G 3) more than control groups post-challenge with vNDV. Delayed onset of mild clinical signs in G3 followed by complete recovery 7th-day post-challenge (DPC). Low MR (40 and 0%) and high protection percent (100 and 60%) in ACEO treated G3 and G5, respectively. spleen, thymus, cecal tonsil, proventriculus, and cerebrum lesions scoring in G3 and G5 were significantly ((p ≤ 0.05).) lower than the control group, proving a decrease in NDV replication and effective antiviral activity of ACEO. HI titer significantly increased (p ≤ 0.05) In G3, G4 and G5 compared with control groups. There is no significant difference in HI titer in ACEO treated groups and vaccinated groups. In conclusion, oral administration of ACEO combined with NDV vaccines significantly reduces or eliminates lethal clinical signs, lesions, viral shedding, and enhances immune response and protection percent after vNDV challenge proving the natural antiviral and immune stimulant effect of ACEO onion extract. Implementing such a regime might aid NDV control in broiler flocks in endemic areas and reduce the epidemiological load of NDV in the environment.     

RbgA ensures the correct timing in the maturation of the 50S subunits functional sites

RbgA is an essential protein for the assembly of the 50S subunit in Bacillus subtilis. Depletion of RbgA leads to the accumulation of the 45S intermediate. A strain expressing a RbgA variant with reduced GTPase activity generates spontaneous suppressor mutations in uL6. Each suppressor strain accumulates a unique 44S intermediate. We reasoned that characterizing the structure of these mutant 44S intermediates may explain why RbgA is required to catalyze the folding of the 50S functional sites. We found that in the 44S particles, rRNA helices H42 and H97, near the binding site of uL6, adopt a flexible conformation and allow the central protuberance and functional sites in the mutant 44S particles to mature in any order. Instead, the wild-type 45S particles exhibit a stable H42-H97 interaction and their functional sites always mature last. The dependence on RbgA was also less pronounced in the 44S particles. We concluded that the binding of uL6 pauses the maturation of the functional sites, but the central protuberance continues to fold. RbgA exclusively binds intermediates with a formed central protuberance and licenses the folding of the functional sites. Through this mechanism, RbgA ensures that the functional sites of the 50S mature last.