Heterologous production and detection of recombinant directing 2-deoxystreptamine (DOS) in the non-aminoglycoside-producing host Streptomyces venezuelae YJ003

2-Deoxystreptamine is a core aglycon that is vital to backbone formation in various aminoglycosides. This core structure can be modified to develop hybrid types of aminoglycoside antibiotics. We obtained three genes responsible for 2-deoxystreptamine production, neo7, neo6, and neo5, which encode 2-deoxy-scyllo-inosose synthase, L-glutamine: 2-deoxy-scyllo-inosose aminotransferase, and dehydrogenase, respectively, from the neomycin gene cluster. These genes were cloned into pIBR25, a Streptomyces expression vector, resulting in pNDOS. The recombinant pNDOS was transformed into a non-aminoglycoside-producing host, Streptomyces venezuelae YJ003, for heterologous expression. Based on comparisons of the retention time on LC-ESI/MS and ESIMS data with those of the 2-deoxystreptamine standard, a compound produced by S. venezuelae YJ003/pNDOS was found to be 2-deoxystreptamine.     

Mapping of quantitative trait loci for basmati quality traits in rice (<Emphasis Type="Italic">Oryza sativa</Emphasis> L.)

Traditional basmati rice varieties are very low yielding due to their poor harvest index, tendency to lodging and increasing susceptibility to foliar diseases; hence there is a need to develop new varieties combining the grain quality attributes of basmati with high yield potential to fill the demand gap. Genetic control of basmati grain and cooking quality traits is quite complex, but breeding work can be greatly facilitated by use of molecular markers tightly linked to these traits. A set of 209 recombinant inbred lines (RILs) developed from a cross between basmati quality variety Pusa 1121 and a contrasting quality breeding line Pusa 1342, were used to map the quantitative trait loci (QTLs) for seven important quality traits namely grain length (GL), grain breadth (GB), grain length to breadth ratio (LBR), cooked kernel elongation ratio (ELR), amylose content (AC), alkali spreading value (ASV) and aroma. A framework molecular linkage map was constructed using 110 polymorphic simple sequence repeat (SSR) markers distributed over the 12 rice chromosomes. A number of QTLs, including three for GL, two for GB, two for LBR, three for aroma and one each for ELR, AC and ASV were mapped on seven different chromosomes. While location of majority of these QTLs was consistent with the previous reports, one QTL for GL on chromosomes 1, and one QTL each for ELR and aroma on chromosomes 11 and 3, respectively, are being reported here for the first time. Contrary to the earlier reports of monogenic recessive inheritance, the aroma in Pusa 1121 is controlled by at least three genes located on chromosomes 3, 4 and 8, and similar to the reported association of badh2 gene with aroma QTL on chromosome 8, we identified location of badh1 gene in the aroma QTL interval on chromosome 4. A discontinuous 5 + 3 bp deletion in the seventh exon of badh2 gene, though present in all the RILs with high aroma, was not sufficient to impart this trait to the rice grains as many of the RILs possessing this deletion showed only mild or no aroma expression. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

A physiological comparative study of acid tolerance of <Emphasis Type="Italic">Lactobacillus plantarum</Emphasis> ZDY 2013 and <Emphasis Type="Italic">L. plantarum</Emphasis> ATCC 8014 at membrane and cytoplasm levels

This study aimed to disclose the acid tolerance mechanism of Lactobacillus plantarum by comparing L. plantarum ZDY 2013 with the type strain L. plantarum ATCC 8014 in terms of cell membrane, energy metabolism, and amino acid metabolism. L. plantarum ZDY 2013 had a superior growth performance under acidic condition with 100-fold higher survival rate than that of L. plantarum ATCC 8014 at pH 2.5. To determine the acid tolerance physiological mechanism, cell integrity was investigated through scanning electron microscopy. The study revealed that L. plantarum ZDY 2013 maintained cell morphology and integrity, which is much better than L. plantarum ATCC 8014 under acid stress. Analysis of energy metabolism showed that, at pH 5.0, L. plantarum ZDY 2013 enhanced the activity of Na⁺/K⁺-ATPase and decreased the ratio of NAD⁺/NADH in comparison with L. plantarum ATCC 8014. Similarly, amino acid metabolism of intracellular arginine, glutamate, and alanine was improved in L. plantarum ZDY 2013. Correspondingly, the activity of arginine deiminase and glutamate decarboxylase of L. plantarum ZDY 2013 increased by 1.2-fold and 1.3-fold compared with L. plantarum ATCC 8014 in acid stress. In summary, it is demonstrated that the special physiological behaviors (integrity of cell membrane, enhanced energy metabolism, increased amino acid and enzyme level) of L. plantarum ZDY 2013 can protect the cells from acid stress.     

Individual‐specific variation in the respiratory activities of HMECs and their bioenergetic response to IGF1 and TNFα

Metabolic reprograming is a hallmark of cancer cells. However, the roles of pre‐existing differences in normal cells metabolism toward cancer risk is not known. In order to assess pre‐existing variations in normal cell metabolism, we have quantified the inter‐individual variation in oxidative metabolism of normal primary human mammary epithelial cells (HMECs). We then assessed their response to selected cytokines such as insulin growth factor 1 (IGF1) and tumor necrosis factor alpha (TNFα), which are associated with breast cancer risk. Specifically, we compared the oxidative metabolism of HMECs obtained from women with breast cancer and without cancer. Our data show considerable inter‐individual variation in respiratory activities of HMECs from different women. A bioenergetic parameter called pyruvate‐stimulated respiration (PySR) was identified as a key distinguishing feature of HMECs from women with breast cancer and without cancer. Samples showing PySR over 20% of basal respiration rate were considered PySR^+ve and the rest as PySR^?ve. By this criterion, HMECs from tumor‐affected breasts (AB) and non‐tumor affected breasts (NAB) of cancer patients were mostly PySR^?ve (88% and 89%, respectively), while HMECs from non‐cancer patients were mostly PySR^+ve (57%). This suggests that PySR^?ve/+ve phenotypes are individual‐specific and are not caused by field effects due to the presence of tumor. The effects of IGF1 and TNFα treatments on HMECs revealed that both suppressed respiration and extracellular acidification. In addition, IGF1 altered PySR^?ve/+ve phenotypes. These results reveal individual‐specific differences in pyruvate metabolism of normal breast epithelial cells and its association with breast cancer risk.

     

Sequence analyses and comparative modeling of fly and worm fibroblast growth factor receptors indicate that the determinants for FGF and heparin binding are retained in evolution.

The presence of a large number of fibroblast growth factors (FGFs) and multiple splice forms of their receptors (FGFRs) in higher vertebrates makes the three-dimensional (3D) analysis of FGF interactions with their receptors a formidable task. The situation differs in Caenorhabditis elegans (worm) and Drosophila melanogaster (fruit fly), where only one or two FGF and FGFR sequences have been identified. Structural studies of the FGF-FGFR complexes in such primitive organisms should reveal the basic features of the ligand-receptor interactions as they first emerged through evolution. We have analysed the sequences of worm and fly FGFs and FGFRs and used the recently determined crystal structure of the human FGF1-FGFR2-heparin ternary complex [Pellegrini, L., Burke, D.F., von Delft, F., Mulloy, B. and Blundell, T.L. (2000) Nature 407, 1029-34] to construct 3D models of the homologous complexes. In spite of a low sequence similarity with their human counterparts, key structural features required for ligand-receptor and protein-heparin binding in humans are conserved in the fly and worm FGF-FGFR-heparin complexes. Analyses of the models show that tertiary interactions that are not conserved in sequence are maintained through novel interactions or complementary mutations in the fly and worm sequences. The overall charge distributions observed in the human FGF-FGFR-heparin complex are retained in the fly and worm models. The arginine residue at position 253 in the linker region between the Ig-like domains D2 and D3 in the wild type fly and worm sequences is particularly striking, as the Pro253Arg mutation in humans is responsible for Apert syndrome. This change may enhance the affinity of receptors for their FGF molecules as observed in Apert mutants.     

Polystyrene—an inert carrier for Lxxx-glutaminase production by marine Vibrio costicola under solid-state fermentation

Polystyrene beads, impregnated with mineral salts/glutamine medium as inert support, were used to produce Lxxx-glutaminase from Vibrio costicola by solid-state fermentation. Maximum enzyme yield, 88 U/g substrate, was after 36 h. Glucose at 10 g/kg enhanced the enzyme yield by 66%. The support system allowed glutaminase to be recovered with higher specific activity and lower viscosity than when a wheat-bran system was used.The authors are with the Microbial Technology Unit, Centre for Biotechnology, Cochin University of Science and Technology, Cochin-682 022, India     

Yoga for bronchial asthma: a controlled study.

Fifty three patients with asthma underwent training for two weeks in an integrated set of yoga exercises, including breathing exercises, suryanamaskar, yogasana (physical postures), pranayama (breath slowing techniques), dhyana (meditation), and a devotional session, and were told to practise these exercises for 65 minutes daily. They were then compared with a control group of 53 patients with asthma matched for age, sex, and type and severity of asthma, who continued to take their usual drugs. There was a significantly greater improvement in the group who practised yoga in the weekly number of attacks of asthma, scores for drug treatment, and peak flow rate. This study shows the efficacy of yoga in the long term management of bronchial asthma, but the physiological basis for this beneficial effect needs to be examined in more detail.     

Development and characterization of a conditional mitochondrial complex I assembly system

We developed a conditional complex I assembly system in a Chinese hamster fibroblast mutant line, CCL16-B2, that does not express the NDUFA1 gene (encoding the MWFE protein). In this mutant, a hemagglutinin (HA) epitope-tagged MWFE protein was expressed from a doxycycline-inducible promoter. The expression of the protein was absolutely dependent on the presence of doxycycline, and the gene could be turned off completely by removal of doxycycline. These experiments demonstrated a key role of MWFE in the pathway of complex I assembly. Upon induction the MWFE.HA protein reached steady-state levels within 24 h, but the appearance of fully active complex I was delayed by another approximately 24 h. The MWFE appeared in a precomplex that probably includes one or more subunits encoded by mtDNA. The fate of MWFE and the stability of complex I were themselves very tightly linked to the activity of mitochondrial protein synthesis and to the assembly of subunits encoded by mtDNA (ND1-6 and ND4L). This novel conditional system can shed light not only on the mechanism of complex I assembly but emphasizes the role of subunits previously thought of as "accessory." It promises to have broader applications in the study of cellular energy metabolism and production of reactive oxygen species and related processes.     

Design,Analysis, and Characterization of Designer Surface Plasmon Polariton-Based Dual-Band Antenna

This paper reports development, design, and analysis of designer (or spoof) surface plasmon polariton-based feeding configuration to excite a dual-band antenna. As an example, a planar transverse electric and magnetic horn antenna is designed and fed by the proposed transition structure. Designer surface plasmon polariton modes are supported by a metal surface at microwave frequency when it is corrugated with periodical grooves. An efficient transition for converting quasi-transverse electric and magnetic waves of microstrip line into spoof surface plasmon polariton (SSPP) waves has been designed in microwave frequency range using periodically corrugated metal strip. SSPP wave is confined at the teeth part of the corrugation. Simulated and measured reflection and transmission characteristics are in good agreement. The spoof SPP-fed dual-band antenna is designed, fabricated, and characterized in microwave anechoic chamber and measured results are coincident with simulated results.