Isosojagol,a coumestan from Phaseolus coccineus

A novel coumestan isolated from Phaseolus coccineus has been characterized as 3,9-dihydroxy-10-(γ,γ-dimethylallyl)-coumestan and named isosojagol.     

Heterologous Production of Antimicrobial Peptides in Propionibacterium freudenreichii

Heterologous bacteriocin production in Propionibacterium freudenreichii is described. We developed an efficient system for DNA shuttling between Escherichia coli and P. freudenreichii using vector pAMT1. It is based on the P. freudenreichii rolling-circle replicating plasmid pLME108 and carries the cml(A)/cmx(A) chloramphenicol resistance marker. Introduction of the propionicin T1 structural gene (pctA) into pAMT1 under the control of the constitutive promoter (P₄) yielded bacteriocin in amounts equal to those of the wild-type producer Propionibacterium thoenii 419. The P. freudenreichii clone showed propionicin T1 activity in coculture, killing 90% of sensitive bacteria within 48 h. The pamA gene from P. thoenii 419 encoding the protease-activated antimicrobial peptide (PAMP) was cloned and expressed in P. freudenreichii, resulting in secretion of the pro-PAMP protein. Like in the wild type, PAMP activation was dependent on externally added protease. Secretion of the antimicrobial peptide was obtained from a clone in which the pamA signal peptide and PAMP were fused in frame. The promoter region of pamA was identified by fusion of putative promoter fragments to the coding sequence of the pctA gene. The P₄ and P_pamp promoters directed constitutive gene expression, and activity of both promoters was enhanced by elements upstream of the promoter core region.     

Construction, characterization, and preliminary BAC-end sequencing analysis of a bacterial artificial chromosome library of white clover (Trifolium repens L.).

White clover (Trifolium repens L.) is a forage legume widely used in combination with grass in pastures because of its ability to fix nitrogen. We have constructed a bacterial artificial chromosome (BAC) library of an advanced breeding line of white clover. The library contains 37 248 clones with an average insert size of approximately 85 kb, representing an approximate 3-fold coverage of the white clover genome based on an estimated genome size of 960 Mb. The BAC library was pooled and screened by polymerase chain reaction (PCR) amplification using both white clover microsatellites and PCR-based markers derived from Medicago truncatula, resulting in an average of 6 hits per marker; this supports the estimated 3-fold genome coverage in this allotetraploid species. PCR-based screening of 766 clones with a multiplex set of chloroplast primers showed that only 0.5% of BAC clones contained chloroplast-derived inserts. The library was further evaluated by sequencing both ends of 724 of the clover BACs. These were analysed with respect to their sequence content and their homology to the contents of a range of plant gene, expressed sequence tag, and repeat element databases. Forty-three microsatellites were discovered in the BAC-end sequences (BESs) and investigated as potential genetic markers in white clover. The BESs were also compared with the partially sequenced genome of the model legume M. truncatula with the specific intention of identifying putative comparative-tile BACs, which represent potential regions of microsynteny between the 2 species; 14 such BACs were discovered. The results suggest that a large-scale BAC-end sequencing strategy has the potential to anchor a significant proportion of the genome of white clover onto the gene-space sequence of M. truncatula.     

Stunting at 2 Years in Relation to Body Composition at 9 Years in African Urban Children**

Objective: To determine whether African urban children who were stunted at 2 years of age demonstrated an altered body composition by the end of childhood, before entering puberty, at 9 years of age. Research Methods and Procedures: This was a mixed‐longitudinal study of 330 prepubertal African children (182 boys) from Soweto‐Johannesburg, South Africa. Anthropometric data at 2 years of age were compared with anthropometric, DXA‐determined body composition and fat patterning in late childhood (7 to 9 years). Results: Children who had been stunted at 2 years were significantly shorter and lighter than non‐stunted children at 7 to 9 years, but there were no differences in their BMI or centralization of body fat. Previously stunted status significantly predicted reduced weight and height at 7 to 9 years but did not predict BMI, body composition, or fat patterning after controlling for potential confounding factors. The odds ratio for stunting at 2 years as a predictor of overweight at 7 to 9 years was not significant at 1.09 (95% confidence limits: 0.30, 3.98). Discussion: Greater BMI in stunted infants does not demonstrate a tendency toward overweight or obesity but is a reflection of the greater reduction in height rather than weight in stunted children. Stunted children may be programmed to accumulate greater body fat at central sites during adolescence, but we have been unable to show that these changes are evident before the initiation of pubertal development.     

Vitamin E up-regulates arachidonic acid release and phospholipase A2 in megakaryocytes

The alteration in calcium transport in the liver nuclei of rats orally administered carbon tetrachloride (CCl4) was investigated. Rats received a single oral administration of CCl₄(5, 10, and 25%, 1.0ml/100 g body weight), and 5, 24 and 48 h later the animals were sacrificed. The administration of CCl₄ (25%) caused a remarkable elevetion of calcium content in the liver tissues and the nuclei of rats. Liver nuclear Ca2+-ATPase activity was markedly decreased by CCl₄ (25%) administration. The presence of dibutyryl cyclic AMP(10^-4 and 10^-3 M) or inositol 1,4,5-trisphosphate (10^-6 and 10^-5 M) in the enzyme reaction mixture caused a significant decrease in Ca²⁺-ATPase activity in the liver nuclei obtained from normal rat, while the enzyme activity was significantly increased by calmodulin (1.0 and 2.0 g/ml). These signaling factor's effects were completely impaired in the liver nuclei obtained from CCl₄ (25%)-administered rats. DNA fragmentation in the liver nuclei obtained from CCl₄ -administered rats was significantly decreased by the presence of EGTA (2 mM) in the reaction mixture, suggesting that the endogenous calcium activates nuclear DNA fragmentation. The present study demonstrates that calcium transport system in the liver nuclei is impaired by liver injury with CCl₄ administration in rats.     

A cationic nonselective stretch-activated channel in the Reissner's membrane of the guinea pig cochlea

The Reissner's membrane (RM) separates in the mammalian cochleathe K⁺-rich endolymph from theNa⁺-rich perilymph. Thepatch-clamp technique was used to investigate the transport mechanismsin epithelial cells of RM freshly dissected from the guinea pigcochlea. This study shows a stretch-activated nonselective cationicchannel (SA channel) with a linear current-voltage relationship (23 pS)highly selective for cations over anions [K⁺  Na⁺ (1) > Ba²⁺ (0.65) > Ca²⁺ (0.32)  Cl (0.14)] andactivated by the intrapipette gradient pressure. The openprobability-pressure relationship is best fitted by a Boltzmanndistribution (half-maximal pressure = 37.8 mmHg, slope constant = 8.2 mmHg). SA channels exhibit a strong voltage dependency and areinsensitive to internal Ca²⁺, ATP,and fenamates but are blocked by 1 µMGdCl₃ in the pipette. They arereversibly activated by in situ superfusion of the cell with hyposmoticsolutions. Kinetic studies show that depolarization and mechanical orosmotic stretch modify the closed and open time constants probably by adifferent mechanism. These channels could participate inpressure-induced modifications of ionic permeability of the RM.

     

Construction of a genome-anchored,high-density genetic map for melon (<Emphasis Type="Italic">Cucumis melo</Emphasis> L.) and identification of <Emphasis Type="Italic">Fusarium oxysporum</Emphasis> f. sp. <Emphasis Type="Italic">melonis</Emphasis> race 1 resistance QTL

Key message

Four QTLs and an epistatic interaction were associated with disease severity in response to inoculation with Fusarium oxysporum f. sp. melonis race 1 in a recombinant inbred line population of melon.

Abstract

The USDA Cucumis melo inbred line, MR-1, harbors a wealth of alleles associated with resistance to several major diseases of melon, including powdery mildew, downy mildew, Alternaria leaf blight, and Fusarium wilt. MR-1 was crossed to an Israeli cultivar, Ananas Yok’neam, which is susceptible to all of these diseases, to generate a recombinant inbred line (RIL) population of 172 lines. In this study, the RIL population was genotyped to construct an ultra-dense genetic linkage map with 5663 binned SNPs anchored to the C. melo genome and exhibits the overall high quality of the assembly. The utility of the densely genotyped population was demonstrated through QTL mapping of a well-studied trait, resistance to Fusarium wilt caused by Fusarium oxysporum f. sp. melonis (Fom) race 1. A major QTL co-located with the previously validated resistance gene Fom-2. In addition, three minor QTLs and an epistatic interaction contributing to Fom race 1 resistance were identified. The MR-1 × AY RIL population provides a valuable resource for future QTL mapping studies and marker-assisted selection of disease resistance in melon.

     

Prey consumption and survival of the predatory mite,Amblydromalus limonicus,on different prey and host plants

Amblydromalus limonicus consumed fewer first instar Frankliniella occidentalis thrips than Bactericera cockerelli psyllids per day when on the same (1.7 thrips, 3.7 psyllids) or separate (2.9 thrips, 4.4 psyllids) capsicum leaf discs. Mites ate fewer psyllids per day on tomato (1.9) than on capsicum (3.1). Mite survival was similar on both prey and plants.