Evaluation of “sequence-tagged-site” PCR products as molecular markers in wheat

The polymerase chain reaction (PCR) is an attractive technique for many genome mapping and characterization projects. One PCR approach which has been evaluated involves the use of randomly amplified polymorphic DNA (RAPD). An alternative to RAPDs is the sequence-tagged-site (STS) approach, whereby PCR primers are designed from mapped low-copy-number sequences. In this study, we sequenced and designed primers from 22 wheat RFLP clones in addition to testing 15 primer sets that had been previously used to amplify DNA sequences in the barley genome. Our results indicated that most of the primers amplified sequences that mapped to the expected chromosomes in wheat. Additionally, 9 of 16 primer sets tested revealed polymorphisms among 20 hexaploid wheat genotypes when PCR products were digested with restriction enzymes. These results suggest that the STS-based PCR analysis will be useful for generation of informative molecular markers in hexaploid wheat.Contribution no. J-2833 of the Montana Agric Exp Stn     

Effects of omnivorous shrimp in a montane tropical stream: sediment removal,disturbance of sessile invertebrates and enhancement of understory algal biomass

Freshwater shrimp dominate the faunal biomass of many headwater tropical streams: however, their role in community organization is unclear. Enclosure/exclosure experiments in a montane Puerto Rican stream examined direct and indirect effects of two dominant taxa of atyid (Atyidae) shrimp, Atya lanipes Holthuis and Xiphocaris elongata Guerin-Meneville. Both shrimp taxa caused significant reductions in sediment cover on rock substrata, reducing sedimentation and enhancing algal biovolume on clay tiles in cages. When tiles incubated in shrimp exclosures for 2 wks were placed outside of cages, atyid shrimp removed 100% of the sediment cover within a 30 min observation period. Atyid shrimp appear to play an important role in stream recovery after high discharge events by rapidly removing sediments and detritus deposited on benthic substrata in pools. We evaluated the mechanism by which A. lanipes influences algae and benthic insects by comparing patterns of algal biomass, taxonomic composition, and insect abundance between shrimp-exclusion and shrimp-presence treatments both with and without manual sediment removal. The shrimp exclusion treatment without manual sediment removal bad significantly lower algal biomass and greater sedimentation than all other treatments. The treatment in which shrimp were excluded but sediment was manually removed, however, accrued almost the same algal biovolume as the shrimp enclosure treatment, supporting the hypothesis that sediment removal enhances the biovolume of understory algal taxa. Algal community composition was similar between stream bottom bedrock exposed to natural densities of shrimp and all experimental treatments for both Atya and Xiphocaris: a diatom community strongly dominated (78–95%) by the adnate taxon, Achnanthes lanceolata Breb ex. Kutz. Atyid shrimp are important in determining the distribution and abundance of benthic insects through both direct and indirect effects. Sessile, retreat-building chironomid larvae (Chironomidae: Diptera) are negatively affected by both A. lanipes and X. elongata, through direct removal by foraging activities and/or indirectly through depression of sediment resources available to larvae for the construction of retreats. In constrast, the mobile grazer, Cloeodes maculipes (Baetidae: Ephemeroptera) was not adversely affected and atyid shrimp have the potential to exert positive indirect effects on this taxon by facilitating its exploitation of algal resources and/or through enhancement of understory algal food resources through sediment removal.     

Changes of 6-benzylaminopurine and 2,4-dichlorophenoxyacetic acid concentrations in plant tissue culture media in the presence of activated charcoal

Somatic embryos and embryogenic callus were initiated from immature zygotic embryos of ginseng (Panax ginseng C.A. Meyer). These somatic embryos were multiplied by adventitious (secondary and tertiary) embryogenesis and their growth and development were dependent on growth hormones in the medium. Auxins, 2,4-d, NAA, and IAA at 1.0 mg l^-1 were effective in inducing secondary and tertiary somatic embryos, which proliferated directly from the apical or cotyledonary portions of the primary somatic embryos. Single somatic embryos or clusters or embryos developed from the explanted primary embryos. Cytokinin (Kn, BA) inhibited adventitious embryogenesis. Secondary somatic embryos developed to maturation and later regenerated into plantlets in two stage process; firstly elongation of the shoot axes on MS +1.0 mg l^-1 Kn, secondly formation of root on 1.0 mg l^-1 Kn+1.0 mg^-1 GA₃ medium.Abbreviations 2,4-d 2,4-dichlorophenoxyacetic acid - NAA naphthaleneacetic acid - IAA in-doleacetic acid - Kn kinetin - BA benzylaminopurine - PSE primary somatic embryo - SSE secondary somatic embryo - TSE tertiary somatic embryo     

A molecular,isozyme and morphological map of the barley (Hordeum vulgare) genome

A map of the barley genome consisting of 295 loci was constructed. These loci include 152 cDNA restriction fragment length polymorphism (RFLP), 114 genomic DNA RFLP, 14 random amplified polymorphic DNA (RAPD), five isozyme, two morphological, one disease resistance and seven specific amplicon polymorphism (SAP) markers. The RFLP-identified loci include 63 that were detected using cloned known function genes as probes. The map covers 1,250 centiMorgans (cM) with a 4.2 cM average distance between markers. The genetic lengths of the chromosomes range from 124 to 223 cM and are in approximate agreement with their physical lengths. The centromeres were localized to within a few markers on all of the barley chromosomes except chromosome 5. Telomeric regions were mapped for the short (plus) arms of chromosomes 1, 2 and 3 and the long (minus) arm of chromosomes 7.This research was also supported by other members of the NABGMP: K. Kasha, Department of Crop Science, University of Guelph, Guelph, Ontario, Canada NIG 2W1; W. Kim, Agriculture Canada Research Station, 195 Dafoe Road, Winnipeg, Manitoba, Canada R3T 2M9; A. Laroche, Agriculture Canada Research Station, P.O. Box 3000 Main, Lethbridge, Alberta, Canada,TU 4B1; S. Molnar, Plant Research Centre Agriculture Canada, Central Experimental farm, Ottawa, Ontario, Canada K1A 0C6; G. Scoles, Department of Crop Science, University of Saskatchewan, Saskatoon, Saskatchewan, Canada S7N OWOThis research is part of the North American Barley Genome Mapping Project, R. A. Nilan and K. Kasha, Coordinator and Associate Coordinator, respectively Permanent address: Department of Plant Genetics, NI Vavilov Institute of General Genetics, Russian Academy of Sciences, Moscow     

The Role of Reactive Oxygen Species in Inflammatory Disease: Evaluation of Methodology

The production of reactive oxidants has been implicated in the pathology of a number of inflammatory conditions, including inflamed arthritic joints. Many assays for the detection of these oxidants in diseased states have been described, but there are a number of potential pitfalls in both experimental design and the interpretation of results obtained with these techniques. Here, we describe a number of commonly used assays to detect the production of reactive oxidants and critically discuss their usefulness and limitations. We focus on the role of xanthine oxidase in reactive oxidant production in inflammatory disease.     

The heterogeneity of bovine growth hormone. Extraction from the pituitary of components with different biological and immunological properties.

Evidence is available to suggest that Ca2+-calmodulin and cyclic nucleotides are involved in the regulation of ion transport in rabbit ileum. Since both Ca2+-calmodulin and cyclic nucleotides exert many of their effects by phosphorylation, the effects of Ca2+-calmodulin and cyclic nucleotides on phosphorylation of purified microvillus membrane from rabbit ileal mucosa were evaluated. Ca2+-calmodulin increased phosphorylation of five microvillus-membrane peptides, with Mr values of 137000, 77000, 58000, 53000 and 50000. The increases in phosphorylation caused by Ca2+-calmodulin were: Mr-137000 peptide, 111 +/- 26%; Mr-77000 peptide, 71 +/- 17%; Mr-58000 peptide, 51 +/- 8%; Mr-53000 peptide, 113 +/- 20%. These increases were maximal at 1 microM-calmodulin and 0.3-0.9 microM free Ca2+; concentrations of Ca2+ causing half-maximal effects on phosphorylation for the different peptides were 0.06-0.12 microM. Cyclic AMP and cyclic GMP increased phosphorylation of two peptides, of Mr 137000 and 85000. The concentrations of cyclic nucleotides giving half-maximal phosphorylation of the Mr-137000 peptide were 0.3 microM-cyclic AMP and 4.6 microM-cyclic GMP, and for the Mr-85000 peptide, 3.9 microM-cyclic AMP and 0.05 microM-cyclic GMP. The maximal increase in phosphorylation of the Mr-137000 peptide was 200% for cyclic AMP and 95% for cyclic GMP, and that of the Mr-85000 peptide was 220% for cyclic AMP and 120% for cyclic GMP. These studies demonstrate the existence of Ca2+-calmodulin-, cyclic AMP- and cyclic GMP-dependent protein kinases and substrate proteins in purified rabbit ileal microvillus membranes and that Ca2+ can regulate phosphorylation of these proteins over the presumed physiological concentration range of cytosol free Ca2+.     

Aspects of the reproductive biology of Hippopotamyms pictus from Lake Kainji, with notes on four other mormyrid species

A method is described for the assessment of fecundity in mormyrid fish. In all species examined a tri-modal egg size distribution was found in the mature pre-spawning ovary. These modes represented one oocyte and two ova components. The significance of the presence of two sizes of ovum is discussed in relation to breeding periodicity in Hippopotamyrus pictus . Size and age at first maturity are estimated for this species. The probable effects of the formation of the lake on the breeding behaviour of mormyrids is discussed.