Antigenic nature of the chloride-stimulated cellobiosidase and other cellulases of Fibrobacter succinogenes subsp. succinogenes S85 and related fresh isolates.

Polyclonal and monoclonal antibodies to the Cl-stimulated cellobiosidase of Fibrobacter succinogenes subsp. succinogenes S85 reacted with numerous proteins of both higher and lower molecular weights from F. succinogenes subsp. succinogenes S85, but not with Escherichia coli proteins, and only one protein each from Butyrivibrio fibrisolvens and Ruminococcus albus. Different profiles were observed for Western blots (immunoblots) of peptide digests of both the purified enzyme from F. succinogenes and immunoreactive proteins of higher and lower molecular weights, demonstrating that they were different proteins. Therefore, F. succinogenes appeared to produce numerous proteins with one or more common antigenic determinants. However, with the exception of Cl-stimulated cellobiosidase, none were cellulases that have been characterized. An affinity-purified polyclonal antibody to Cl-stimulated cellobiosidase reacted with numerous proteins in cells of each of three fresh isolates of F. succinogenes subsp. succinogenes and one of F. succinogenes subsp. elongata when analyzed by Western blotting. Antibodies to periplasmic cellodextrinase, endoglucanase 2 (EG2), and EG3, when reacted in Western blots with the various cellulases, including Cl-stimulated cellobiosidase, revealed limited antigenic similarity among the different proteins and none with either B. fibrisolvens or R. albus proteins. The periplasmic cellodextrinase antibody reacted with an antigen with a size corresponding to cellodextrinase in each of the three F. succinogenes subsp. succinogenes isolates but not with any antigens from the F. succinogenes subsp. elongata isolate. The anti-EG2 antibody reacted with single antigens in each of the four isolates, while the anti-EG3 antibody reacted with only one of the four isolates.(ABSTRACT TRUNCATED AT 250 WORDS)     

Identification and some properties of a unique DNA polymerase from cells infected with human B-lymphotropic virus.

A new DNA polymerase and DNase activity were identified from cells infected with human B-lymphotropic herpesvirus (HBLV). DNA polymerase associated with HBLV infection was similar in its sensitivity to inhibition by ppi analogs as other herpesvirus-specific DNA polymerases but was dissimilar in its inhibition by certain nucleoside triphosphates.     

Reduction of Selenate and Selenite to Elemental Selenium by a Pseudomonas stutzeri Isolate

A Pseudomonas stutzeri isolate rapidly reduced both selenite and selenate ions to elemental selenium at initial concentrations of both anions of up to 48.1 mM. Optimal selenium reduction occurred under aerobic conditions between pH 7.0 and 9.0 and at temperatures of 25 to 35°C. Reduction of both selenite and selenate was unaffected by a number of anions except for sulfite, chromate, and tungstate ions, which inhibited both growth and reduction.     

Regulation by thyroid hormone of the synthesis of a cytosolic thyroid hormone binding protein during liver regeneration.

To understand the regulation by thyroid hormone, 3,3',5-triiodo-L-thyronine (T3), of the synthesis of a cytosolic thyroid hormone binding protein (p58-M2) during liver regeneration, the synthesis of p58-M2 was evaluated. The synthesis of p58-M2 was measured by metabolic labeling of primary cultures derived from the regenerating liver of euthyroid, hypo- or hyperthyroid rats. During regeneration, the increase in the liver/body weight ratio is approximately 25% higher in hyper- than in hypothyroid rats. However, T3 has no effect on the rate of overall liver regeneration observed in four days. In mature liver, T3 increased the synthesis of p58-M2 by approximately 2.5-fold. During regeneration, however, the change in the synthesis of p58-M2 varied with the thyroid status. In euthyroid rats, the synthesis of p58-M2 continued to increase up to 2-fold during liver regeneration. In hyperthyroid rats, after an initial increase by 1.5-fold on day 1, the synthesis of p58-M2 subsequently declined during regeneration. In hypothyroid rats, the synthesis of p58-M2 remained virtually unchanged during regeneration. These results indicate that T3 regulates the synthesis of p58-M2 in mature and regenerating liver.     

Characterization of a 56-kb plasmid of Erwinia amylovora Ea322: its noninvolvement in pathogenicity

A plasmid from Erwinia amylovora strain Ea322, pCPP60, was studied for its involvement in the phytopathogenicity of this strain. Eviction through incompatibility and curing with acridine orange did not affect the pathogenic capability of Ea322. The plasmid was characterized as self-transmissible with a narrow host range. Hybridization of its origin of replication with plasmids of different incompatibility groups revealed affiliation with IncF. The exact subgroup was not determined, although it does not belong to IncFI, IncFII, IncFIV, or IncFV. A sequence of 800 bp, required for conjugation in cis, was cloned in pUC9. A "miniplasmid" containing the origin of replication in a 1.2-kb sequence was constructed. Its high copy number was in contrast with the stringently controlled copy number of the native plasmid of one to three copies per chromosome equivalent.     

Variability of entrainment of cohesive sediments in freshwater

Estimates of sediment entrainment are required for models of particle transport in lakes and estuaries but are difficult to make because of the multiplicity of factors affecting cohesiveness of surficial sediments. We present results of sediment resuspension studies performed in an annular flume calibrated with laser-Doppler velocimetry. In our experiments, using sediments collected from two sites in the R. Raisin which flows into L. Erie and from one site in the western basin of L. Erie near the mouth of the R. Raisin, we applied shear stresses at the sediment-water interface in steps from 2 to 12 dyne/cm². Percent water content at the surface of the sediments was either 77 or 74%, and trials were run with and without oxygenating the water overlying the sediments. Entrainment rates as a function of shear stress at the sediment-water interface were best described by a power-law relationship. All but 14% of the variability in the power law expression was due to shear stress and percent water content; the variability not accounted for was due to differences in particle size distributions, chemical properties, and biological activity in the sediments.     

Preliminary study of the distribution of the toxic elements As,Cd, and Hg in human hair and tissues by RNAA

In order to study the relationships between trace element concentrations of hair and internal body burdens, a radiochemical NAA technique has been used for determination of the elements As, Cd, and Hg in autopsy samples of liver, kidney-cortex, lung, and hair from 24 male persons who died by accident. High significant positive correlations were observed between the As concentration in hair and in kidney-cortex, and between Cd and Zn concentrations in kidney-cortex. The contents of Cd, both for lung and kidney-cortex, were related to the smoking habits of the subjects.

     

温州蜜柑果实发育过程中矿质营养元素含量的动态变化

本文分析了温州蜜柑丰产园不同发育阶段的果实氮、磷、钾、钙、镁、铁、锰、锌、铜、硼的含量。矿质元素在果实中的动态变化规律与叶片中的变化规律显然不同。一是含量比叶片低;二是浓度的最高峰期出现比叶片早。果实发育前中期元素含量变化较复杂,9月以后趋向稳定。对可否以9月至10月上旬作为采果样时期以进行营养诊断作了讨论。     

Adherence Patterns and DNA Probe Types of Escherichia coli Isolated from Diarrheal Patients in China

One hundred and seventy-two strains of Escherichia coli isolated from diarrheal patients in Beijing, P. R. China, were analyzed for plasmid DNA profile, HEp-2 cell adherence ability and reactivity to 10 previously described DNA probes. They had not been recognized as pathogenic E. coli in China. Of the 110 strains tested, 76 (69%) contained one or multiple large plasmids. Of the 71 strains with the large plasmids 64 could adhere to HEp-2 cells. Of the 172 strains, 102 (59.3%) were hybridized with at least one of the 10 probes. Of those, seven strains hybridized with enteroaggregative E. coli (EAggEC) probe. Their serotypes were O128 (two strains), O6 (one strain), and O111 (one strain). Three strains were untypable. Six and three strains were hybridized with enteropathogenic E. coli (EPEC) attaching and effacing genes (eae) or EPEC adherence factor (EAF) probe, respectively. Two non-O157: H7 strains hybridized with enterohemorrhagic E. coli (EHEC) probe. Seventy-two strains (41.9%) hybridized with shiga-like toxin 2 or 1 (SLT2 or SLT1) probes. Among the SLT1 or SLT2 probe-positive strains, 54 hybridized with invasive (INV) plasmid probe developed for identification of enteroinvasive E. coli (EIEC) and Shigella species. The INV and SLT probe-positive strains might represent a new variety of verotoxin-producing E. coli (VTEC).