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971.
Frequency of Erwinia carotovora in the Alyth Burn in eastern Scotland and the sources of the bacterium 总被引:3,自引:3,他引:0
Contamination of the Alyth Burn by Erwinia carotovora was monitored monthly over 2 years at nine sites spread over a distance of ca 20 km. The bacterium was detected only once in the upper reaches of the river where it flows in uninhabited moorland but frequency of detection and contamination level tended to increase progressively as the river flowed through the middle reaches mostly in grassland to the lower reaches in arable land where the bacterium was almost always present. Erwinia populations rose from < 102 cells/1 before May to frequently > 103 but < 104 cells/l thereafter at sites in the arable land zone. A similar pattern was found in the grassland zone except that erwinia numbers were lower. Erwinia numbers at one site in the arable land zone were positively and negatively correlated with the river water temperature and flow rate respectively when there was a 1 month lag between the environmental data and the population recorded. More than 80% of isolates tested were E. carotovora subsp. carotovora.
Water from field drains in arable fields, especially those recently planted with potatoes, was frequently contaminated by E.c. carotovora , with numbers and a temporal pattern similar to those of the Alyth Burn. Drainage water from non-arable fields was rarely contaminated. Infected and rotting potatoes deposited in rivers temporarily contaminated the water. Survival of E. carotovora in dilute phosphate buffer was greater at pH 5˙7 than at pH 7˙7 and they survived for at least 10 d in river water. 相似文献
Water from field drains in arable fields, especially those recently planted with potatoes, was frequently contaminated by E.c. carotovora , with numbers and a temporal pattern similar to those of the Alyth Burn. Drainage water from non-arable fields was rarely contaminated. Infected and rotting potatoes deposited in rivers temporarily contaminated the water. Survival of E. carotovora in dilute phosphate buffer was greater at pH 5˙7 than at pH 7˙7 and they survived for at least 10 d in river water. 相似文献
972.
LINDA M. McINNES IAN R. DADOUR MEREDITH E. STEWART WILLIAM G. F. DITCHAM PETER MAWSON PETER B. S. SPENCER 《Molecular ecology resources》2005,5(3):504-506
Microsatellite loci were isolated from Carnaby's black cockatoo (Calyptorhynchus latirostris: Aves), a highly valued, endangered, and endemic species of bird from Western Australia. This study describes three dinucleotide and one tetranucleotide microsatellite loci for which the primers produced clear and polymorphic amplification patterns with between two and nine alleles and moderate levels of variability. Two additional dinucleotide markers which were monomorphic in the Carnaby's cockatoo were able to amplify and were polymorphic in two other species of black cockatoo, greatly increasing the utility of these markers. 相似文献
973.
974.
Purification and characterization of a lysophospholipase from human amnionic membranes 总被引:1,自引:0,他引:1
We have identified the presence of a lysophospholipase in human placental tissues and have purified this enzyme from the amnion. The specific activity was highest in the amnion and decreased across adjacent tissues. The purification involved the use of DEAE-Sephadex, phenyl-Sepharose, hydroxylapatite, and sulfylpropyl Sephadex chromatography. The activity of the purified enzyme toward palmitoyl lysophosphatidylcholine is 2.5 mumol min-1 mg-1 and the pH optimum is 7.0. The enzyme is not inhibited by EDTA and does not appear to have a metal ion requirement. The enzyme may be of membrane origin; the purified enzyme requires the presence of detergent during storage. The effects of substrate composition and physical state on enzymatic activity were explored. The enzyme was not active toward mono-, di-, or triglycerides, nor toward diacyl phospholipid. The enzyme was active toward myristoyl and palmitoyl lysophosphatidylcholine at concentrations where these substrates spontaneously form micelles or where Triton X-100 was used to induce co-micellization of the substrate at low concentrations with detergent. A role for this enzyme in processing the lysophospholipid product of phospholipase A action must be considered in evaluating arachidonic acid production in human fetal membranes and placental tissue, particularly during the initiation of labor. 相似文献
975.
976.
Cs. Leranth H. Sakamoto N. J. MacLusky M. Shanabrough F. Naftolin 《Histochemistry and cell biology》1985,82(2):165-168
Summary A pre-embedding immunostaining procedure was developed using ferritin and peroxidase to enable simultaneous electron microscopic localization of two antigens in the same tissue section. This method was used to study the anatomic relationship between glutamic acid decarboxylase (GAD) immunoreactive axons and tyrosine hydroxylase (TH) — containing neurons of the rat arcuate nucleus. The findings provide ultrastructural evidence that GAD-immunoreactive terminals establish symmetric (Gray II) synapses on TH-reactive neurons. 相似文献
977.
978.
During 1975--77 Hemophilus vaginalis bacteremia occurred post partum in eight previously healthy women. Seven had been admitted for delivery at term and one because of threatened abortion. Six underwent cesarean section. Post-partum pyrexia and neutrophilia were the main features. All the patients recovered uneventfully while receiving antibiotics. H. vaginalis is an infrequent agent of bacteremia; it affects predominantly women after obstetric trauma. 相似文献
979.
Water hyacinth (Eichhornia crassipes), duckweed (Spirodela sp. andLemna sp.), water pennywort (Hydrocotyle ranunculoides), and kudzu (Pueraria lobata) were anaerobically fermented using an anaerobic filter technique that reduced the total digestion time from 90 d to an average of 23 d and produced 0.14-0.22 m3 CH4/kg (dry weight) (2.3-3.6 ft3/lb) from mature filters for the 3 aquatic species. Kudzu required an average digestion time of 33 d and produced an average of 0.21 m3 CH4/kg (dry weight) (3.4 ft3/lb). The anaerobic filter provided a large surface area for the anaerobic bacteria to establish and maintain an optimal balance of facultative, acid-forming, and methane-producing bacteria. Consequently the efficiency of the process was greatly improved over prior batch fermentations. 相似文献
980.
J S Buckner D R Nelson C L Fatland H Hakk J G Pomonis 《The Journal of biological chemistry》1984,259(13):8461-8470
Ester components in the surface wax from diapausing tobacco hornworm pupae, Manduca sexta L., were separated by thin layer chromatography and gas-liquid chromatography, and characterized by infrared spectroscopy and gas-liquid chromatography-mass spectrometry. Three groups of esters were identified as natural derivatives of acetic acid, acetoacetic acid, and 3-hydroxybutyric acid. The major ester fraction was identified as a mixture of C26 (10%), C27 (5%), and C28 (85%) oxoalcohol esters of acetoacetic acid. The major homolog consisted of equal amounts of 11-oxooctacosanyl 3-oxobutanoate and 12-oxooctacosanyl 3-oxobutanoate. Lesser amounts of 11- and 12-oxooctacosanyl and n-octacosanyl esters of acetic and 3-hydroxybutyric acids were also identified. The chain length distributions of these C26, C27, and C28 oxoalcohol and n-primary alcohol ester moieties, as well as the isomeric ratios for the 11- and 12-oxoalcohol isomers, were similar to the oxoaldehydes and unesterified oxoalcohols previously identified by Buckner et al (Buckner, J. S., Nelson, D. R., Haak, H., and Pomonis, J. G. (1984) J. Biol. Chem. 259, 8452-8470) as lipid components of the surface wax of M. sexta pupae. 相似文献