Use of the Chrome Azurol S Agar Plate Technique To Differentiate Strains and Field Isolates of Rhizobium leguminosarum biovar trifolii

Identification of Rhizobium and Bradyrhizobium strains and especially of indigenous isolates continues to be one of the major difficulties associated with competition studies. Because there is no universally accepted method, the method of choice depends on preference, experience, and equipment. Here, an agar plate technique was used to distinguish strains and field isolates of Rhizobium leguminosarum biovar trifolii to provide a basis for identifying nodule occupants in further competition studies. A rapid plate technique, based on differential growth characteristics, complements other techniques such as serological reactions, particularly when antisera cross-react with nonhomologous strains. The technique involves culturing strains and isolates on chrome azurol S agar. Although similar responses were observed among some strains, the response was highly reproducible and was considered an ideal complementary technique used in conjunction with serological procedures. Strains with similar responses could often be differentiated by varying media components, such as the source of carbon.     

Capture myopathy in wild turkeys (Meleagris gallopavo) following trapping, handling and transportation in Colorado

Sixty wild turkeys were necropsied following trapping, transporting and handling during the winters of 1980-1981, 1981-1982, and 1982-1983 in order to determine the incidence of subclinical capture myopathy. Gross lesions characterized by small to large patchy, pale white streaked areas within skeletal muscle were found in 13 of 27 birds trapped with a drop net in the winter of 1982-1983. Microscopic lesions within myocardium characterized by irregular areas of coagulative necrosis, collapse of intercellular stroma and myocardial nuclear proliferation were found in two of 14 birds in 1980-1981, five of 19 birds in 1981-1982 and 11 of 27 birds in 1982-1983. Microscopic lesions within skeletal muscle characterized by rhabdomyolysis were found in 16 of 19 birds in 1981-1982 and 25 of 27 birds in 1982-1983. These findings suggest that wild turkeys are susceptible to capture myopathy and particular caution should be exercised in capturing and handling these birds.     

Cell cycle analysis with bromodeoxyuridine pulselabeling in asynchronous hybridoma cultures

Summary The cell cycle kinetics of a mouse hybridoma was examined by immunocytochemical staining of incorporated bromodeoxyuridine in an asynchronous culture. The cell cycle phase traverse times were extracted from a time series of bivariate distributions of incorporated bromodeoxyuridine and total DNA content; the G₁, S and G₂/M phase traverse times were 7, 9 and 4 h, respectively in the exponential growth phase.     

Hitch-hiking from HRAS1 to the WAGR locus with CMGT markers.

The clinical association of Wilms' tumour with aniridia, genitourinary abnormalities and mental retardation (WAGR syndrome) is characterised cytogenetically by variable length, constitutional deletion of the short arm of chromosome 11, which always includes at least part of band 11p13. HRAS1-selected chromosome mediated gene transfer (CMGT) generated a transformant, E65-6, in which the only human genes retained map either to band 11p13 or, with HRAS1, in the region 11p15.4-pter. Human recombinants isolated from E65-6 were mapped to a panel of five WAGR deletion hybrids and two clinically related translocations. We show that E65-6 is enriched congruent to 400-fold for 11p15.4-pter markers and congruent to 200-fold for 11p13 markers. 'Hitch-hiking' from HRAS1 with CMGT markers has allowed us to define seven discrete intervals which subtend band 11p13. Both associated translocations co-locate within the smallest region of overlap for the WAGR locus, which has been redefined by identifying a new interval closer than FSHB.     

Chromosomal changes in cell lines from mouse tumors induced by nickel sulfide and methylcholanthrene

Rhabdomyosarcomas were induced in mice by intramuscular injections of crystalline nickel sulfide and 3-methylcholanthrene. At early passage, karyotypes were performed by G-banding for four nickel sulfide cell lines and for three 3-methylcholanthrene cell lines. Six cell lines were near-diploid and one nickel sulfide line was near-tetraploid. Three of the nickel sulfide cell lines were characterized by a rearranged marker chromosome which was present in a majority of the cells of each line. The rearrangements leading to the formation of marker chromosomes were different in each nickel sulfide cell line but involved chromosome 4 in two of the nickel sulfide cell lines. Extra copies of chromosome 15 were present in two nickel sulfide cell lines. Possible rearrangement and/or gene activation was examined for the c-mos oncogene on chromosome 4 and the c-myc oncogene on chromosome 15, but no alteration or activation was observed. None of the 3-methylcholanthrene cell lines contained rearranged marker chromosomes; however, one MCA cell line did contain large numbers of double minutes. In all cell lines, minichromosomes (small atypical acrocentric chromosomes) were observed that contained distinct centromeric regions but no other G-positive bands.Abbreviations DHFR dihydrofolate reductase - MCA 3-methylcholanthrene - NS nickel sulfide     

Antisera to synthetic peptide recognize high molecular weight enkephalin-containing proteins

Antisera to a synthetic peptide corresponding to the 95-117 sequence of proenkephalin were used to develop a sensitive radioimmunoassay. Gel-filtration of acid extracts of bovine adrenal medulla and purified chromaffin granules revealed that the antisera recognized high molecular weight material (Mr approximately 5,000-30,000). The material in peak I ( Mr 20 ,000-30,000) and peak II (Mr 10,000-20,000) was further purified by immunoaffinity chromatography. Sequential digestion of each of these fractions with trypsin and carboxypeptidase B generated immunoreactive Met-enkephalin. This study demonstrates that antisera against a synthetic peptide cross-react with high molecular weight enkephalin-containing precursors, validating the use of these antisera in studies of enkephalin biosynthesis.     

Botanical aspects of Acidic precipitation

Acidic precipitation can be characterized as wet or frozen atmospheric deposition with a hydrogen ion concentration greater than 2.5 μeq liter^-1. Acidic precipitation is perceived as a significant air pollution problem derived chiefly from combustion of fossil fuels, smelting of sulfide metals, and other industrial processes. Precipitation data from the northeastern United States show a mean pH of between 4.0 and 4.2 with a range of from 3.0 to 6.0 among individual events. Although visible injury to plant foliage has been documented in a variety of studies only one case of visible foliar injury from the acidity in ambient rainfalls has been documented. Acidic precipitation can contribute nutrients to vegetation and could also influence nutrient leaching rates from vegetation. Although these processes occur, there are no data that show changes in nutrient levels in foliage that relate to crop or natural ecosystem productivity. Although no consistent patterns are presently known, acidic precipitation may affect host-plant pathogen interactions. Few experiments with field-grown crops or vegetation under natural conditions have been performed. Many of the studies are inadequate because they have been conducted with inadequate replication of treatments coupled with vigorous statistical analyses. Studies with field-grown crops are evaluated. Acidification of fresh waters of the northeastern United States is caused by acid deposition. Such regions in which this acidification occurs have in common, volume weighted mean H⁺ concentrations of 25μeq liter-1 or higher and slow weathering of granitic or Precambrian bedrock with thin soils deficient in minerals that provide buffering capacity. As freshwater acidification occurs, many plants, invertebrates, and vertebrates are progressively eliminated. Generally, fisheries are severely impacted when lake pH falls below 5.0. Fish are almost always eliminated when the lake pH is below 4.8.     

Characterization of DNA lesions produced by HgCl2 in cell culture systems

HgCl2 is extremely cytotoxic to Chinese hamster ovary (CHO) cells in culture since a 1-h exposure to a 75- microM concentration of this compound reduced cell plating efficiency to 0 and cell growth was completely inhibited at 7.5 microM . The level of HgCl2 toxicity depended upon the culture incubation medium and has previously been shown to be inversely proportional to the extracellular concentration of metal chelating amino acids such as cysteine. Thus, HgCl2 toxicity in a minimal salts/glucose maintenance medium was about 10-fold greater than the toxicity in McCoy's culture medium. The HgCl2 toxicity in the latter medium was 3-fold greater than that in alpha-MEM which contains more of the metal chelating amino acids. When cells were exposed to HgCl2 there was a rapid and pronounced induction of single strand breaks in the DNA at time intervals and concentrations that paralleled the cellular toxicity. The DNA damage was shown to be true single strand breaks and not alkaline sensitive sites or double strand breaks by a variety of techniques. Consistent with the toxicity of HgCl2, the DNA damage under an equivalent exposure situation was more pronounced in the salts/glucose than in the McCoy's medium and more striking in the latter medium than in alpha-MEM. Most of the single strand breaks occurred within 1 h of exposure to the metal. We believe that the DNA damage caused by HgCl2 leads to cell death because the DNA single strand breaks are not readily repaired. DNA repair activity measured by CsCl density gradient techniques was elevated above the untreated levels at HgCl2 concentrations that produced little measurable binding of the metal to DNA or few single strand breaks assessed by the alkaline elution procedure. DNA repair activity decreased at HgCl2 concentrations that produced measurable DNA binding and single strand breaks. These irreversible interactions of HgCl2 with DNA may be responsible for its cytotoxic action in cells.