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      Volume 31, Issue 2

      June 2006,   pages  177-292

    • Simple laboratory tests of ecological theories: What we can learn from them, and when we should be cautious

      Mike S Fowler Lasse Ruokolainen

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    • Limbs: Gains and losses

      Ashok Sahni

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    • Hypoxia, hyperoxia and breathing

      Henry Gautier

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      This short Commentary has been limited to a few of several studies. They clearly indicate that the mechanisms involved in the effects of hypoxia and hyperoxia on the ventilatory control and particularly on theintegrative respiratory centres are far from being completely understood and are now believed to be more complex than what was postulated 40 years ago. Other mechanisms, which are beyond the scope of this short review, are currently the subjects of numerous studies which suggest that mediators or modulators are involved not only at the periphery but also at the level of the central nervous system. It must be emphasized that all these recent studies do not contradict at all, but rather help to explain, the early findings of Pierre Dejours concerning the participation of the peripheral chemoreceptors in the regulation and control of breathing.

    • The extent of Charles Darwin’s knowledge of Mendel

      Andrew Sclater

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    • Kenneth Raper, Elisha Mitchell andDictyostelium

      Eugene R Katz

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    • Living in a physical world VII. Gravity and life on the ground

      Steven Vogel

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    • What history tells us V. Emile Duclaux (1840–1904)

      Michel Morange

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      Perhaps we should be more cautions in our vision of how a scientist should behave, a perception closely tied to the present-day organization of scientific research — with its extreme specialization. Is the present situation optimal? And was not the huge spectrum of activities and interests of Emile Duclaux also necessary for the rapid development of microbiology and its general acceptance? We should not reduce the history of medicine to a catalog of the discoverers of diseases. As a scientific organizer, and a prime mover in the development of microbiology, Emile Duclaux deserves a place in our memories.

    • Interactions of carbohydrates and proteins by fluorophore-assisted carbohydrate electrophoresis

      Gang-Liang Huang Xin-Ya Mei Peng-George Wang

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      A sensitive, specific, and rapid method for the detection of carbohydrate-protein interactions is demonstrated by fluorophore-assisted carbohydrate electrophoresis (FACE). The procedure is simple and the cost is low. The advantage of this method is that carbohydrate-protein interactions can be easily displayed by FACE, and the carbohydrates do not need to be purified.

    • Pleurotus sajor-caju HSP100 complements a thermotolerance defect inhsp104 mutantSaccharomyces cerevisiae

      Jin-Ohk Lee Mi-Jeong Jeong Tack-Ryun Kwon Seung-Kon Lee Myung-Ok Byun Ill-Min Chung Soo-Chul Park

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      A putativeHsp100 gene was cloned from the fungusPleurotus sajor-caju. mRNA expression studies demonstrated that this gene (designatedPsHsp100) is highly induced by high temperature, induced less strongly by exposure to ethanol, and not induced by drought or salinity. Heat shock induction is detectable at 37‡C and reaches a maximum level at 42‡C.PsHsp100 mRNA levels sharply increased within 15 min of exposure to high temperature, and reached a maximum expression level at 2 h that was maintained for several hours. These results indicate that PsHsp100 could work at an early step in thermotolerance. To examine its function,PsHsp100 was transformed into a temperature-sensitivehsp104 deletion mutantSaccharomyces cerevisiae strain to test the hypothesis that PsHSP100 is an protein that functions in thermotolerance. Overexpression of PsHSP100 complemented the thermotolerance defect of thehsp104 mutant yeast, allowing them survive even at 50‡C for 4 h. These results indicate that PsHSP100 protein is functional as an HSP100 in yeast and could play an important role in thermotolerance inP. sajor-caju.

    • Genetic transformation of peanut (Arachis hypogaea L.) using cotyledonary node as explant and a promoterlessgus::nptII fusion gene based vector

      T Swathi Anuradha S K Jami R S Datla P B Kirti

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      We have generated putative promoter tagged transgenic lines inArachis hypogaea cv JL-24 using cotyledonary node (CN) as an explant and a promoterless gus::nptII bifunctional fusion gene mediated byAgrobacterium transformation. MS medium fortified with 6-benzylaminopurine (BAP) at 4 mg/l in combination with 0.1 mg/l α-napthaleneacetic acid (NAA) was the most effective out of the various BAP and NAA combinations tested in multiple shoot bud formation. Parameters enhancing genetic transformation viz. seedling age,Agrobacterium genetic background and co-cultivation periods were studied by using the binary vector p35SGUSINT. Genetic transformation with CN explants from 6-day-old seedlings co-cultivated withAgrobacterium GV2260 strain for 3 days resulted in high kanamycin resistant shoot induction percentage (45%); approximately 31% transformation frequency was achieved with p35S GUSINT in Β-glucuronidase (GUS) assays. Among thein vivo GUS fusions studied with promoterless gus::nptII construct, GUS-positive sectors occupied 38% of the total transient GUS percentage. We have generated over 141 putative T0 plants by using the promoterless construct and transferred them to the field. Among these, 82 plants survived well in the green house and 5 plants corresponding to 3.54% showed stable integration of the fusion gene as evidenced by GUS, polymerase chain reaction (PCR) and Southern blot analyses. Twenty-four plants were positive for GUS showing either tissue-specific expression or blue spots in at least one plant part. The progeny of 15 T0 plants indicated Mendelian inheritance pattern of segregation for single-copy integration. The tissue-specific GUS expression patterns were more or less similar in both T0 and corresponding T1 progeny plants. We present the differential patterns of GUS expression identified in the putative promoter-tagged transgenic lines in the present communication.

    • The analysis of proteome changes in sunflower seeds induced by N+ implantation

      Dong Guijun Pan Weidong Liu Gongshe

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      In this work, the proteomic changes induced by N+ ion implantation were investigated using a sunflower seed model by a two-dimensional electrophoretic analysis. To further understand the changes of total protein irradiated with N+ ion, a proteomic analysis of N+ ion implantation seeds was developed. Among approximately 369 total protein spots displayed in 2-D gels, eight specific proteins were found in non-implanted seeds while four proteins were found in implanted seeds. Six proteins were used for MALDI-TOF MS analysis, of which only two had been reported before. The proteins designated as No. 29 showed 23.4% homology to MADS-box transcriptional factor HAM59, while No. 279 protein had 23.20% identity to homeobox-leucine zipper protein HAHB-4. The analysis of proteome changes induced by N+ implantation could provid a new clue to studing mutation mechanism of ion implantation. To our knowledge, this is the first report about the analysis of proteome changes induced by N+ implantation in sunflower seeds.

    • Overexpression ofGbERF confers alteration of ethylene-responsive gene expression and enhanced resistance toPseudomonas syringae in transgenic tobacco

      Jie Qin Kaijing Zuo Jingya Zhao Hua Ling Youfang Cao Chengxiang Qiu Fupeng Li Xiaofen Sun Kexuan Tang

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      GbERF belongs to the ERF (ethylene responsive factor) family of transcription factors and regulates the GCC-box containing pathogen-related (PR) genes in the ethylene signal transduction pathway. To study the function of GbERF in the process of biotic stress, transgenic tobacco plants expressingGbERF were generated. Overexpression ofGbERF did not change transgenic plant’s phenotype and endogenous ethylene level. However, the expression profile of some ethylene-inducible GCC-box and non-GCC-box containing genes was altered, such asPR1b, PR2, PR3, PR4,Osmotin, CHN50, ACC oxidase and ACC synthase genes. These data indicate that the cotton GbERF could act as a transcriptional activator or repressor to regulate the differential expression of ethylene-inducible genes via GCC and non-GCCcis-elements. Moreover, the constitutive expression ofGbERF in transgenic tobacco enhanced the plant’s resistance toPseudomonas syringae pvtabaci infection. In conclusion,GbERF mediates the expression of a wide array ofPR and ethylene-responsive genes and plays an important role in the plant’s response to biotic stress.

    • Genetically modified cyanobacteriumNostoc muscorum overproducing proline in response to salinity and osmotic stresses

      Santosh Bhargava

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      In the parentNostoc muscorum an active proline oxidase enzyme is required to assimilate exogenous proline as a fixed nitrogen source. Cyanobacterial mutants, resistant to growth inhibitory action of proline analogue L-azetidine-2-carboxylate (Ac-R), were deficient in proline oxidase activity, and were over-accumulators of proline. Proline over-accumulation, resulting either from mutational acquisition of the Ac-R phenotype, or from salinity-induced uptake of exogenous proline, confirmed enhanced salinity/osmotic tolerance in the mutant strain. The nitrogenase activity and photosynthetic O2 evolution of the parent were sensitive to both salinity as well as osmotic stresses than of Ac-R mutant strain. In addition, the mutation to Ac-resistant phenotype showed no alteration in salinity inducible potassium transport system in the cyanobacterium.

    • Bicarbonate kinetics in Indian males

      T Raj R Kuriyan A V Kurpad

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      Measurement of rates ofin vivo substrate oxidation such as that of glucose, fatty acids and amino acids, are based on tracer (14C or13C) data, and often depend on the isotopic content of expired CO2. The recovery of tracer-labelled CO2 generated from the oxidation of13C labelled substrates may not be 100% over short term. This can lead to underestimation of oxidation rate of substrates, and consequently a correction for the incomplete recovery of tracer has to be applied by the determination of the recovery of13CO2 in the breath during tracer bicarbonate infusions. We have studied the recovery of tracer-labelled bicarbonate using a bolus administration model, and further characterized kinetics of bicarbonate using a three-compartment model, to assess which compartmental fluxes changed during the change from a fasted state to fed state. Recovery of bicarbonate was lower at 69% and 67% (fasted and fed state) than the value of 71% and 74% found during earlier longer term of continuous infusions. During feeding, there was a 20-fold increase in the flux of bicarbonate between the central compartment and the compartment that was equivalent to the viscera. This study shows that the difference between the fasted and fed state recovery of tracer bicarbonate similar to that obtained with continuous infusions, and that bicarbonate fluxes show large changes between different compartments in the body depending on metabolic state.

    • Mechanism of recycling of post-termination ribosomal complexes in eubacteria: A new role of initiation factor 3

      Anuradha Seshadri Umesh Varshney

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      Ribosome recycling is a process which dissociates the post-termination complexes (post-TC) consisting of mRNA-bound ribosomes harbouring deacylated tRNA(s). Ribosome recycling factor (RRF), and elongation factor G (EFG) participate in this crucial process to free the ribosomal subunits for a new round of translation. We discuss the overall pathway of ribosome recycling in eubacteria with especial reference to the important role of the initiation factor 3 (IF3) in this process. Depending on the step(s) at which IF3 function is implicated, three models have been proposed. In model 1, RRF and EFG dissociate the post-TCs into the 50S and 30S subunits, mRNAand tRNA(s). In this model, IF3, which binds to the 30S subunit, merely keeps the dissociated subunits apart by its anti-association activity. In model 2, RRF and EFG separate the 50S subunit from the post-TC. IF3 then dissociates the remaining complex of mRNA, tRNA and the 30S subunit, and keeps the ribosomal subunits apart from each other. However, in model 3, both the genetic and biochemical evidence support a more active role for IF3 even at the step of dissociation of the post-TC by RRF and EFG into the 50S and 30S subunits.

    • Erwin Bünning (1906–1990): A centennial homage

      M K Chandrashekaran

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    • Pleurotus sajor-caju HSP100 complements a thermotolerance defect inhsp104 mutantSaccharomyces cerevisiae

      Jin-Ohk Lee Mi-Jeong Jeong Tack-Ryun Kwon Seung-Kon Lee Myung-Ok Byun Ill-Min Chung Soo-Chul Park

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