Small dams need consideration in riverscape conservation assessments

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Effect of dietary amino acids on in vitro rumen bacterial protein synthesis in buffaloes.

The effect of different ratios of urea to amino acid N at a fixed concentration of soluble sugars as energy source and varying levels of soluble sugars at optimum urea cell suspension was obtained from the rumen fluid of buffalo (Bubalus bubalis) calves fed on a growth ration. Under glucose fermentation, the bacterial protein content of the incubation mixture (I. M.) was increased to 3.91, 6.31 and 5.08 times the control value (urea alone) when 25, 50 and 75% of urea-N was replaced with amino acid N, respectively. With cellobiose, the corresponding increase was 4.06, 5.29 and 5.63 times. At 50% urea-N replacement with amino acid N (a ratio for maximum protein synthesis), the bacterial content was maximum when 1 g glucose or cellobiose per 100 ml of I. M. was added. Per cent incorporation of radioactivity from amino acids into bacterial protein was maximum at 25% amino acid N level with both the soluble sugar sources. The total amino acids incorporated into bacterial protein were, however, more at 50% than at 25% amino acid N level.     

Bt cotton producing Cry1Ac and Cry2Ab does not harm the parasitoid Aenasius arizonensis (Girault): a host-mediated tritrophic assay

Phytoparasitica - Transgenic crops with genes from Bacillus thuringiensis (Bt) Berliner, a soil bacterium producing δ-endotoxin that is lethal to several phytophagous insects. Concerns related...     

Genetics of tolerance to high concentrations of boron in Brassica rapa

The inheritance of tolerance to high concentrations of boron in Brassica rapa was studied in F₂ and F₃ segregating populations. The F₁ hybrids were produced from genotypes contrasting in their reaction to boron. The F₁ hybrids responded similarly to the tolerant parent indicating that boron tolerance was dominant trait. Segregation patterns for boron tolerance in F₂ populations and F₃ derived families were established by the measurements of primary root length and tissue boron concentrations. The segregation ratios were explained in terms of two major genes interacting in a dominant epistatic manner to govern tolerance. Evaluation of selected tolerant and susceptible F₃ families indicated that tolerant families produced significantly longer primary roots as compared to susceptible families.     

Association of a novel DNA virus with the grapevine vein-clearing and vine decline syndrome

A severe vein-clearing and vine decline syndrome has emerged on grapevines (Vitis vinifera) and hybrid grape cultivars in the Midwest region of the United States. The typical symptoms are translucent vein-clearing on young leaves, short internodes and decline of vine vigor. Known viral pathogens of grapevines were not closely associated with the syndrome. To obtain a comprehensive profile of viruses in a diseased grapevine, small RNAs were enriched and two cDNA libraries were constructed from a symptomatic grapevine and a symptomless grapevine, respectively. Deep sequencing of the two cDNA libraries showed that the most abundant viral small RNAs align with the genomes of viruses in the genus Badnavirus, the family Caulimoviridae. Amplification of the viral DNA by polymerase chain reaction allowed the assembly of the whole genome sequence of a grapevine DNA virus, which shared the highest homology with the Badnavirus sequences. This is the first report of a DNA virus in grapevines. The new DNA virus is closely associated with the vein-clearing symptom, and thus has been given a provisional name Grapevine vein clearing virus (GVCV). GVCV was detected in six grapevine cultivars showing vein-clearing and vine decline syndrome in Missouri, Illinois, and Indiana, suggesting its wide distribution in the Midwest region of the United States. Discovery of DNA viruses in grapevines merits further studies on their epidemics and economic impact on grape production worldwide.     

Antiviral lead compounds from marine sponges

Marine sponges are currently one of the richest sources of pharmacologically active compounds found in the marine environment. These bioactive molecules are often secondary metabolites, whose main function is to enable and/or modulate cellular communication and defense. They are usually produced by functional enzyme clusters in sponges and/or their associated symbiotic microorganisms. Natural product lead compounds from sponges have often been found to be promising pharmaceutical agents. Several of them have successfully been approved as antiviral agents for clinical use or have been advanced to the late stages of clinical trials. Most of these drugs are used for the treatment of human immunodeficiency virus (HIV) and herpes simplex virus (HSV). The most important antiviral lead of marine origin reported thus far is nucleoside Ara-A (vidarabine) isolated from sponge Tethya crypta. It inhibits viral DNA polymerase and DNA synthesis of herpes, vaccinica and varicella zoster viruses. However due to the discovery of new types of viruses and emergence of drug resistant strains, it is necessary to develop new antiviral lead compounds continuously. Several sponge derived antiviral lead compounds which are hoped to be developed as future drugs are discussed in this review. Supply problems are usually the major bottleneck to the development of these compounds as drugs during clinical trials. However advances in the field of metagenomics and high throughput microbial cultivation has raised the possibility that these techniques could lead to the cost-effective large scale production of such compounds. Perspectives on biotechnological methods with respect to marine drug development are also discussed.     

Molecular mapping of adult plant stripe rust resistance in wheat and identification of pyramided QTL genotypes

The Puccinia striiformis f. sp. tritici (Pst) pathotype, 134 E16A+, detected in 2002 in Australia, produced relatively lower and higher adult plant stripe rust responses, respectively, on cultivars Kukri and Janz in comparison to the pre-2002 Pst pathotype 110 E143A+. Molecular mapping of adult plant stripe rust response variation among 180 Kukri/Janz-derived doubled haploid lines over 4 years, two each with Pst pathotypes 110 E143A+ and 134 E16A+, was performed. QYr.sun-7B and QYr.sun-7D were consistently contributed by Kukri and Janz, respectively. QYr.sun-7D corresponded to the genomic location of Yr18 and QYr.sun-7B remains to be formally named. QYr.sun-1B, QYr.sun-5B, and QYr.sun-6B were detected during more than one season irrespective of the Pst pathotypes used, whereas QYr.sun-3B was identified only during the 2003 crop season. QYr.sun-1A contributed by Janz, and QYr.sun-2A from Kukri, were detected only against Pst pathotypes 110 E143A+ and 134 E16A+, respectively. The DH lines showing better resistance than the either parent carried combinations of 4 to 6 QTL. These lines are currently being used as stripe rust resistance donors in wheat breeding programs.     

Identification of QTLs for resistance to Fusarium wilt and Ascochyta blight in a recombinant inbred population of chickpea (<Emphasis Type="Italic">Cicer arietinum</Emphasis> L.)

Fusarium wilt (FW; caused by Fusarium oxysporum f. sp. ciceris) and Ascochyta blight (AB; caused by Ascochyta rabiei) are two major biotic stresses that cause significant yield losses in chickpea (Cicer arietinum L.). In order to identify the genomic regions responsible for resistance to FW and AB, 188 recombinant inbred lines derived from a cross JG 62 × ICCV 05530 were phenotyped for reaction to FW and AB under both controlled environment and field conditions. Significant variation in response to FW and AB was detected at all the locations. A genetic map comprising of 111 markers including 84 simple sequence repeats and 27 single nucleotide polymorphism (SNP) loci spanning 261.60 cM was constructed. Five quantitative trait loci (QTLs) were detected for resistance to FW with phenotypic variance explained from 6.63 to 31.55%. Of the five QTLs, three QTLs including a major QTL on CaLG02 and a minor QTL each on CaLG04 and CaLG06 were identified for resistance to race 1 of FW. For race 3, a major QTL each on CaLG02 and CaLG04 were identified. In the case of AB, one QTL for seedling resistance (SR) against ‘Hisar race’ and a minor QTL each for SR and adult plant resistance against isolate 8 of race 6 (3968) were identified. The QTLs and linked markers identified in this study can be utilized for enhancing the FW and AB resistance in elite cultivars using marker-assisted backcrossing.