Studies on microbiologically influenced corrosion of SS304 by a novel manganese oxidizer, Bacillus flexus

A manganese oxidizing bacterium was isolated from the surface of steel scraps and biochemical tests and 16S rRNA sequencing analysis confirmed the isolate as Bacillus flexus. Potentiodynamic polarization curves showed ennoblement of open circuit potential, increased passive current, a lowering of breakdown potential, active re-passivation potential and enhanced cathodic current in the presence of B. flexus. Adhesion studies with B. flexus on SS304 specimens with different surface treatments demonstrated decreased adhesion on passivated and FeCl(3) treated specimens due to the removal of MnS inclusions. The present study provides evidence that surface treatment of stainless steels can reduce adhesion of this manganese oxidizing bacterium and decrease the probability of microbiologically influenced corrosion.     

Pattern of Pseudoexfoliation Deposits on the Lens and Their Clinical Correlation- Clinical Study and Review of Literature

Purpose

To study the clinical correlates of pattern of deposits over the lens in patients with pseudoexfoliation syndrome (PXF) or pseudoexfoliation glaucoma.

Methods

This retrospective observational study screened 346 patients with PXF seen in glaucoma clinic of a tertiary hospital from 2011–2013. Details like pattern of deposits, location on the lens surface and pupillary abnormalities in slit lamp photographs and their correlation with clinical and demographic variables, were analysed.

Results

A total of 84 eyes of 42 patients with bilateral PXF were included for the study. Glaucoma was seen in 30 eyes with baseline IOP of 24+3.8 mm Hg. Comparing the type of deposits, namely classical (n = 39 eyes), radial pigmentary (RP) form (n = 39 eyes) and combined classical and radial pigmentary (CR) forms (n = 6 eyes) of deposits, pupillary ruff atrophy was common in all forms while poor dilatation was rare in the RP type (n = 5 vs n = 25 in classical forms, p<0.001). Mean deviation (MD) was worse in the classical and CR form as compared to RP type with the latter presenting much earlier, 43±3.2 years vs 48±4.1 years in CR and 56±5.7 years in classical form, p<0.001. The baseline IOP in the RP group (18±2.3 mm Hg) was significantly lower than the other two forms (CR 20±3.2 mm Hg, classical 28±2.3 mm Hg), p<0.001, with only 2 eyes on anti-glaucoma drugs at presentation.

Conclusion

Pattern of exfoliation deposits may indicate the stage and severity of the disease process in evolution with the RP representing an earlier/less severe form of pseudoexfoliation syndrome.     

Reconstruction of surfaces from mixed hydrocarbon and PEG components in water: responsive surfaces aid fouling release

Coatings derived from surface active block copolymers (SABCs) having a combination of hydrophobic aliphatic (linear hydrocarbon or propylene oxide-derived groups) and hydrophilic poly(ethlyene glycol) (PEG) side chains have been developed. The coatings demonstrate superior performance against protein adsorption as well as resistance to biofouling, providing an alternative to coatings containing fluorinated side chains as the hydrophobe, thus reducing the potential environmental impact. The surfaces were examined using dynamic water contact angle, captive air-bubble contact angle, atomic force microscopy, X-ray photoelectron spectroscopy, and near-edge X-ray absorption fine structure analysis. The PS(8K)-b-P(E/B)(25K)-b-PI(10K) triblock copolymer precursor (K3) initially dominated the dry surface. In contrast to previous studies with mixed fluorinated/PEG surfaces, these new materials displayed significant surface changes after exposure to water that allowed fouling resistant behavior. PEG groups buried several nanometers below the surface in the dry state were able to occupy the coating surface after placement in water. The resulting surface exhibits a very low contact angle and good antifouling properties that are very different from those of K3. The surfaces are strongly resistant to protein adsorption using bovine serum albumin as a standard protein challenge. Biofouling assays with sporelings of the green alga Ulva and cells of the diatom Navicula showed the level of adhesion was significantly reduced relative to that of a PDMS standard and that of the triblock copolymer precursor of the SABCs.     

The role of earthworm Lampito mauritii (Kinberg) in amending lead and zinc treated soil

A laboratory experiment was carried out to determine the effect of earthworm (Lampito mauritii) activity on mobility of Pb2+ and Zn2+ in the soil (DTPA-extractable) and its composting potential in presence of these metals. Well clitellate earthworms collected from an uncontaminated site were exposed to different concentrations (75, 150, 300mgkg(-1)) of Pb2+ and Zn2+ separately for 30 days. It was observed that the metal burden in the earthworm tissue increased with the increase in metal treatment. L. mauritii elevated the soil pH of all the metal treated beds and lowered the soil C/N ratio in the cast by reducing the organic carbon and fixing additional nitrogen. Earthworm activity significantly increased the availability of phosphorous, potassium and decreased the amount of DTPA-extractable Pb2+ and Zn2+ in the cast, which implies the immobilization of metals in soils. These findings suggest the use of L. mauritii in amelioration of metal contaminated soil.     

Monitoring of chemical fertilizers on toxicity of two carbamate insecticides to the cyanobacterium Anabaena PCC 7120

The effects of individual chemical fertilizers (urea, superphosphate and potash) on the toxicity of two carbamate insecticides (carbaryl and carbofuran) to the nitrogen-fixing cyanobacterium Anabaena PCC 7120, were studied in vitro at partial lethal levels of each insecticide. Urea at 10 and 50 ppm levels reduced the toxicity due to carbaryl at 50 ppm partial lethal dose and due to carbofuran at 100 and 250 ppm partial lethal doses. Urea at 100 ppm enchanced the toxicity of both insecticides. Superphosphate at 10 ppm reduced the toxicity of carbaryl at 50 ppm and carbofuran at 100 and 250 ppm, but it enhanced the toxicity due to both insecticides at 50 ppm superphosphate. The toxicity due to carbaryl at 40 and 60 ppm were reduced by 100 and 200 ppm potash, but higher potash levels caused enhancement of toxicity. Carbofuran toxicity at 100 ppm was reduced but at 250 ppm the toxicity was enhanced with 100 ppm potash. Urea, superphosphate and potash caused no significant change in number of vegetative cells between the successive heterocysts at 10 and 50 ppm of urea and superphosphate, respectively, and 100 ppm of potash.     

Ancestral Asian source(s) of new world Y-chromosome founder haplotypes

Haplotypes constructed from Y-chromosome markers were used to trace the origins of Native Americans. Our sample consisted of 2,198 males from 60 global populations, including 19 Native American and 15 indigenous North Asian groups. A set of 12 biallelic polymorphisms gave rise to 14 unique Y-chromosome haplotypes that were unevenly distributed among the populations. Combining multiallelic variation at two Y-linked microsatellites (DYS19 and DXYS156Y) with the unique haplotypes results in a total of 95 combination haplotypes. Contra previous findings based on Y- chromosome data, our new results suggest the possibility of more than one Native American paternal founder haplotype. We postulate that, of the nine unique haplotypes found in Native Americans, haplotypes 1C and 1F are the best candidates for major New World founder haplotypes, whereas haplotypes 1B, 1I, and 1U may either be founder haplotypes and/or have arrived in the New World via recent admixture. Two of the other four haplotypes (YAP+ haplotypes 4 and 5) are probably present because of post-Columbian admixture, whereas haplotype 1G may have originated in the New World, and the Old World source of the final New World haplotype (1D) remains unresolved. The contrasting distribution patterns of the two major candidate founder haplotypes in Asia and the New World, as well as the results of a nested cladistic analysis, suggest the possibility of more than one paternal migration from the general region of Lake Baikal to the Americas.     

Allele frequency of inosine triphosphate pyrophosphatase gene polymorphisms in a Japanese population

The enzyme inosine triphosphate pyrophosphatase (ITPase) catalyses the pyrophosphohydrolysis of ITP to IMP. ITPase deficiency is a clinically benign autosomal recessive condition characterised by the abnormal accumulation of ITP in erythrocytes. A deficiency of ITPase may predict adverse reactions to therapy with the thiopurine drug 6-mercaptopurine and its prodrug azathioprine. In this study, we examine the frequencies of ITPA polymorphisms in 100 healthy Japanese individuals. The allele frequency of the 94C > A variant in the Japanese sample was 0.135 (Caucasian allele frequency 0.06). The IV2 + 21A > C polymorphism was not found in Japanese (Caucasian allele frequency 0.130). Allele frequencies of the 138G > A, 561G > A and 708G > A polymorphisms were 0.57, 0.18 and 0.06 respectively in the Japanese population, and with the exception of the 138G > A polymorphism, similar to allele frequencies in Caucasians.     

Kinetics of salt-dependent unfolding of [2Fe–2S] ferredoxin of <Emphasis Type="Italic">Halobacterium salinarum</Emphasis>

The [2Fe–2S] ferredoxin from the extreme haloarchaeon Halobacterium salinarum is stable in high (>1.5 M) salt concentration. At low salt concentration the protein exhibits partial unfolding. The kinetics of unfolding was studied in low salt and in presence of urea in order to investigate the role of salt ions on the stability of the protein. The urea dependent unfolding, monitored by fluorescence of the tryptophan residues and circular dichroism, suggests that the native protein is stable at neutral pH, is destabilized in both acidic and alkaline environment, and involves the formation of kinetic intermediate(s). In contrast, the unfolding kinetics in low salt exhibits enhanced rate of unfolding with increase in pH value and is a two state process without the formation of intermediate. The unfolding at neutral pH is salt concentration dependent and occurs in two stages. The first stage, involves an initial fast phase (indicative of the formation of a hydrophobic collapsed state) followed by a relatively slow phase, and is dependent on the type of cation and anion. The second stage is considerably slower, proceeds with an increase in fluorescence intensity and is largely independent of the nature of salt. Our results thus show that the native form of the haloarchaeal ferredoxin (in high salt concentration) unfolds in low salt concentration through an apparently hydrophobic collapsed form, which leads to a kinetic intermediate. This intermediate then unfolds further to the low salt form of the protein.     

Identification of a phosphoprotein specifically induced by the transforming DNA of rat neuroblastomas

DNAs from nitrosoethylurea-induced rat neuroblastomas transform NIH/3T3 mouse fibroblasts in a transfection assay. DNAs of such transformed cells can be used in a subsequent cycle of transfection to generate secondary foci that contain virtually no foreign genetic material besides the sequences carrying the rat neuroblastoma transforming function. These secondary neuroblastoma transfectants were injected into young mice and grew out into fibrosarcomas. Sera from these mice were examined for reactivity with any proteins which were induced specifically by the neuroblastoma transforming sequence. These sera precipitate a polypeptide of about 185,000 daltons from ³⁵S-methionine-labeled cell lysates of the rat neuroblastoma cells that served as DNA donors and in all transfection-derived primary and secondary foci. This protein is present in high levels in all neuroblastoma transfectant clones, but was not detectable in a variety of other transformed cells. Antisera were prepared from mice bearing tumors induced by transformed cells derived by transfection of DNAs from various tumor cell types unrelated to rat neuroblastoma. These antisera failed to immunoprecipitate the 185,000 dalton protein. These data indicate that the synthesis of the 185,000 dalton protein is specifically induced by the neuroblastoma transforming sequence. The protein may be encoded by the transforming sequence and may mediate transformation in this chemically induced tumor.