Biochemical pulping of bagasse

This study deals with pretreatment of wheat straw with lignin-degrading fungi and its effect on chemical pulping. Ceriporiopsis subvermispora strains, which preferentially attack the lignin, were used for biochemical pulping of bagasse. Treatment of depithed bagasse with different strains of C. subvermispora reduced the kappa number by 10-15% and increased unbleached pulp brightness by 1.1-2.0 ISO points on chemical pulping at the same alkali charge. Bleaching of biopulps at the same chemical charge increased final brightness by 4.7-5.6 ISO points and whiteness by 10.2-11.4 ISO points. Fungal treatment did not result in any adverse effect on the strength properties of pulp.     

Effect of <Superscript>60</Superscript>Co-Gamma Ionizing Radiation and Desiccation Stress on Protein Profile of <Emphasis Type="Italic">Anabaena</Emphasis> 7120

Physiological stress can bring major molecular and cellular change to a living cell which further decide its survival or tolerance to the stress exposure. Cyanobacteria like Anabaena has been shown to tolerate high levels of different stresses like oxidative, desiccation, UV, and gamma radiation. They are able to withstand and recover remarkably without any lethal mutation when exposed to high doses of gamma radiation or prolonged duration of desiccation. In the present work, the modifications in protein profiles of Anabaena 7120 cells after exposure to 6 kGy of ⁶⁰Co γ-rays and 6 days of desiccation, and the proteome dynamics during post stress recovery were investigated. Differentially expressed proteins during stress and recovery were identified by MALDI-ToF or LC-MS, which generated a partial proteome map of Anabaena 7120. Anabaena cells went through protein recycling—phase of protein degradation following by their resynthesis, which helped them to recover remarkably. The data suggests an overlap in proteome changes during recovery against radiation and desiccation stress.     

Inability ofExserohilum turcicum (Pass.) Leo. et Sug., to survive as a saprophyte in soilin situ

Summary A study of the capacity ofExserohilum turcicum (Pass.) Leo. et Sug., to survive in sorghum field soil gave negative results, proving its inability to survive saprophytically in soil. That alternate graminaceous hosts and low seed-borne nature of the fungus might be involved in causing the seedling blight has been indicated.Deceased on 24th September 1982.     

Conservative site-specific and single-copy transgenesis in human LINE-1 elements

Genome engineering of human cells plays an important role in biotechnology and molecular medicine. In particular, insertions of functional multi-transgene cassettes into suitable endogenous sequences will lead to novel applications. Although several tools have been exploited in this context, safety issues such as cytotoxicity, insertional mutagenesis and off-target cleavage together with limitations in cargo size/expression often compromise utility. Phage λ integrase (Int) is a transgenesis tool that mediates conservative site-specific integration of 48 kb DNA into a safe harbor site of the bacterial genome. Here, we show that an Int variant precisely recombines large episomes into a sequence, termed attH4X, found in 1000 human Long INterspersed Elements-1 (LINE-1). We demonstrate single-copy transgenesis through attH4X-targeting in various cell lines including hESCs, with the flexibility of selecting clones according to transgene performance and downstream applications. This is exemplified with pluripotency reporter cassettes and constitutively expressed payloads that remain functional in LINE1-targeted hESCs and differentiated progenies. Furthermore, LINE-1 targeting does not induce DNA damage-response or chromosomal aberrations, and neither global nor localized endogenous gene expression is substantially affected. Hence, this simple transgene addition tool should become particularly useful for applications that require engineering of the human genome with multi-transgenes.     

Preferential Utilization of Aromatic Compounds over Glucose by Pseudomonas putida CSV86

Pseudomonas putida CSV86, a naphthalene-degrading organism, exhibited diauxic growth on aromatic compounds plus glucose, with utilization of aromatics in the first log phase and of glucose in the second log phase. Glucose supplementation did not suppress the activity of degrading enzymes, which were induced upon addition of aromatic compounds. The induction was inhibited by chloramphenicol, suggesting that de novo protein synthesis was essential. Cells showed cometabolism of aromatic compounds and organic acids; however, organic acids suppressed glucose utilization.     

Insights into the interactions of cyanobacteria with uranium

Due to various activities associated with nuclear industry, uranium is migrated to aquatic environments like groundwater, ponds or oceans. Uranium forms stable carbonate complexes in the oxic waters of pH 7–10 which results in a high degree of uranium mobility. Microorganisms employ various mechanisms which significantly influence the mobility and the speciation of uranium in aquatic environments. Uranyl bioremediation studies, this far, have generally focussed on low pH conditions and related to adsorption of positively charged UO₂ ²⁺ onto negatively charged microbial surfaces. Sequestration of anionic uranium species, i.e. [UO₂(CO₃) ₂ ^2? ] and [UO₂(CO₃) ₃ ^4? ] onto microbial surfaces has received only scant attention. Marine cyanobacteria are effective metal adsorbents and represent an important sink for metals in aquatic environment. This article addresses the cyanobacterial interactions with toxic metals in general while stressing on uranium. It focusses on the possible mechanisms employed by cyanobacteria to sequester uranium from aqueous solutions above circumneutral pH where negatively charged uranyl carbonate complexes dominate aqueous uranium speciation. The mechanisms demonstrated by cyanobacteria are important components of biogeochemical cycle of uranium and are useful for the development of appropriate strategies, either to recover or remediate uranium from the aquatic environments.     

Evolution of dispersal syndrome and its corresponding metabolomic changes

Dispersal is one of the strategies for organisms to deal with climate change and habitat degradation. Therefore, investigating the effects of dispersal evolution on natural populations is of considerable interest to ecologists and conservation biologists. Although it is known that dispersal itself can evolve due to selection, the behavioral, life‐history and metabolic consequences of dispersal evolution are not well understood. Here, we explore these issues by subjecting four outbred laboratory populations of Drosophila melanogaster to selection for increased dispersal. The dispersal‐selected populations had similar values of body size, fecundity, and longevity as the nonselected lines (controls), but evolved significantly greater locomotor activity, exploratory tendency, and aggression. Untargeted metabolomic fingerprinting through NMR spectroscopy suggested that the selected flies evolved elevated cellular respiration characterized by greater amounts of glucose, AMP, and NAD. Concurrent evolution of higher level of Octopamine and other neurotransmitters indicate a possible mechanism for the behavioral changes in the selected lines. We discuss the generalizability of our findings in the context of observations from natural populations. To the best of our knowledge, this is the first report of the evolution of metabolome due to selection for dispersal and its connection to dispersal syndrome evolution.     

An exonuclease I-sensitive DNA repair pathway in Deinococcus radiodurans: a major determinant of radiation resistance

Deinococcus radiodurans R1 recovering from acute dose of gamma radiation shows a biphasic mechanism of DNA double-strand break repair. The possible involvement of microsequence homology-dependent, or non-homologous end joining type mechanisms during initial period followed by RecA-dependent homologous recombination pathways has been suggested for the reconstruction of complete genomes in this microbe. We have exploited the known roles of exonuclease I in DNA recombination to elucidate the nature of recombination involved in DNA double-strand break repair during post-irradiation recovery of D. radiodurans. Transgenic Deinococcus cells expressing exonuclease I functions of Escherichia coli showed significant reduction in gamma radiation radioresistance, while the resistance to far-UV and hydrogen peroxide remained unaffected. The overexpression of E. coli exonuclease I in Deinococcus inhibited DNA double-strand break repair. Such cells exhibited normal post-irradiation expression kinetics of RecA, PprA and single-stranded DNA-binding proteins but lacked the divalent cation manganese [(Mn(II)]-dependent protection from gamma radiation. The results strongly suggest that 3' (rho) 5' single-stranded DNA ends constitute an important component in recombination pathway involved in DNA double-strand break repair and that absence of sbcB from deinococcal genome may significantly aid its extreme radioresistance phenotype.