Isolation and characterization of H₂ oxidizing bacteria in H₂ treated soil and soil adjacent to Hup⁻ soybean nodules

x, 97 leaves : ill. (some col.) ; 28 cm.Includes abstract and appendices.Includes bibliographical references (leaves 78-87).Previous studies have shown that the hydrogen (H₂) gas evolved from legume nodules inoculated by hydrogen releasing (Hup⁻) rhizobium strains contributes to growth promotion of subsequent crop plants by altering the populations of soil H₂ oxidizing bacteria; this may be responsible for the major beneficial effect of legumes in crop rotation. To further study the plant growth promoting bacteria in H₂ treated soil and soil adjacent to the Hup⁻ legume nodules, the H₂ oxidizing bacteria were isolated from H₂ treated soil and soil adjacent to Hup⁻ soybean nodules grown in greenhouse and field. A much higher bacterial density was found in soils with a higher H₂ uptake rate. Twenty isolates of H₂ oxidizing bacteria were obtained. They are slow growing bacteria on mineral salt medium incubated under H₂- enriched air. All H₂ oxidizing bacterial strains exhibited one high K[subscript m] for H₂ at 1000ppm. The isolates of H₂ oxidizing bacteria were identified as Variovorax paradoxus, Flavobacterium johnsonae and Burkholderia sordidicola by conventional microbiological tests and 16S rRNA gene sequence analysis. All isolated H₂ oxidizing bacteria increased the root elongation of spring wheat seedlings ranging from 21% to 254% compared to controls. Seventeen of them had a significantly positive effect on root elongation (p<0.005). The strains of V. paradoxus found in both H₂ treated soil and soil adjacent to Hup⁻ soybean nodules had the highest direct plant growth effect. The results confirm the hypothesis that the microorganisms responsible for the oxidation of H₂ released by Hup⁻ legume nodules are bacteria and they act as plant growth promoting rhizobacteria (PGPR)

A Syllable-Based Technique for Uyghur Text Compression

To improve utilization of text storage resources and efficiency of data transmission, we proposed two syllable-based Uyghur text compression coding schemes. First, according to the statistics of syllable coverage of the corpus text, we constructed a 12-bit and 16-bit syllable code tables and added commonly used symbols&mdash;such as punctuation marks and ASCII characters&mdash;to the code tables. To enable the coding scheme to process Uyghur texts mixed with other language symbols, we introduced a flag code in the compression process to distinguish the Unicode encodings that were not in the code table. The experiments showed that the 12-bit coding scheme had an average compression ratio of 0.3 on Uyghur text less than 4 KB in size and that the 16-bit coding scheme had an average compression ratio of 0.5 on text less than 2 KB in size. Our compression schemes outperformed GZip, BZip2, and the LZW algorithm on short text and could be effectively applied to the compression of Uyghur short text for storage and applications

The tumor suppressor tuberin regulates mitotic onset through the cellular localization of cyclin B1

Tuberous sclerosis is a multi-organ disorder characterized by the formation of benign tumors, called hamartomas, which affect more than 1 million people worldwide. The syndrome is initiated by a mutation in one of two tumor suppressor genes, TSC1 or TSC2 which encode for the proteins hamartin and tuberin, respectively. Herein we demonstrate that tuberin binds and regulates the G(2)/M cyclin, cyclin B1. We have determined that this binding region encompasses a mutational hotspot within tuberin implicated in some of the most severe cases of TS. Mimicking a mutation found in a subset of patients with Tuberous sclerosis we found a significant reduction in the binding between tuberin and cyclin B1. Functionally, our data supports that tuberin plays a role in regulating the cellular localization of cyclin B1. These results demonstrate a novel and clinically relevant mechanism where tuberin functions in mitotic onset

pH Effects on Bio-Permeability of Natural Rubber Latex Polymers

Barrier materials used in medical gloves and condoms to prevent the penetration of infectious agents are of utmost importance for the preservation of public health. Surrogate viruses have proven effective as conservative measures of infectious potential. Previous work has tested the integrity of barrier materials exposed to a host of pressures and stresses, however none have tested the effects of pH exposure mimicking that prevailing through coitus. We optimized the use of bacteriophage ФX174 and PCR detection to conduct a pilot study on the effects of pH on the viral penetration of latex condoms. Our results suggest that exposure of condoms to acidic pH ranges of physiological significance increases the frequency of condom failure rate. This proof of principal work supports the need for a larger study to investigate the significance of these effects over a wide range of condom brands

Autophagy governs protumorigenic effects of mitotic slippage-induced senescence

The most commonly utilized class of chemotherapeutic agents administered as a first-line therapy are antimitotic drugs; however, their clinical success is often impeded by chemoresistance and disease relapse. Hence, a better understanding of the cellular pathways underlying escape from cell death is critical. Mitotic slippage describes the cellular process where cells exit antimitotic drug-enforced mitotic arrest and "slip" into interphase without proper chromosome segregation and cytokinesis. The current report explores the cell fate consequence following mitotic slippage and assesses a major outcome following treatment with many chemotherapies, therapy-induced senescence. It was found that cells postslippage entered senescence and could impart the senescence-associated secretory phenotype (SASP). SASP factor production elicited paracrine protumorigenic effects, such as migration, invasion, and vascularization. Both senescence and SASP factor development were found to be dependent on autophagy. Autophagy induction during mitotic slippage involved the autophagy activator AMPK and endoplasmic reticulum stress response protein PERK. Pharmacologic inhibition of autophagy or silencing of autophagy-related ATG5 led to a bypass of G1 arrest senescence, reduced SASP-associated paracrine tumorigenic effects, and increased DNA damage after S-phase entry with a concomitant increase in apoptosis. Consistent with this, the autophagy inhibitor chloroquine and microtubule-stabilizing drug paclitaxel synergistically inhibited tumor growth in mice. Sensitivity to this combinatorial treatment was dependent on p53 status, an important factor to consider before treatment.Implications: Clinical regimens targeting senescence and SASP could provide a potential effective combinatorial strategy with antimitotic drugs.NRF (Natl Research Foundation, S’pore)MOE (Min. of Education, S’pore)Accepted versio