Himasthla quissetensis: uptake and utilization of glucose by rediae as determined by autoradiography and respirometry

Daughter rediae of Himasthla quissetensis removed from the digestive gland of Nassarius obsoletus were placed in sterilized seawater fortified with antibiotics. When [³H]-glucose was added to this medium and autoradiographs were made after 3, 9, and 24 hr of exposure, labeling was observed associated with the redial walls and developing germ balls and cercariae within the brood chambers. Respirometric determinations on starved rediae suspended in the seawater medium with and without glucose revealed the rate of oxygen utilization by rediae exposed to exogenous glucose is significantly elevated. These results are interpreted to mean that the daughter rediae of H. quissetensis can take up and utilize glucose.     

Synteny on mouse chromosome 5 of homologs for human DNA loci linked to the Huntington disease gene

Comparative mapping in man and mouse has revealed frequent conservation of chromosomal segments, offering a potential approach to human disease genes via their murine homologs. Using DNA markers near the Huntington disease gene on the short arm of chromosome 4, we defined a conserved linkage group on mouse chromosome 5. Linkage analyses using recombinant inbred strains, a standard outcross, and an interspecific backcross were used to assign homologs for five human loci, D4S43, D4S62, QDPR, D4S76, and D4S80, to chromosome 5 and to determine their relationships with previously mapped markers for this autosome. The relative order of the conserved loci was preserved in a linkage group that spanned 13% recombination in the interspecific backcross analysis. The most proximal of the conserved markers on the mouse map, D4S43h, showed no recombination with Emv-1, an endogenous ecotropic virus, in 84 outcross progeny and 19 recombinant inbred strains. Hx, a dominant mutation that causes deformities in limb development, maps approximately 2 cM proximal to Emv-1. Since the human D4S43 locus is less than 1 cM proximal to HD near the telomere of chromosome 4, the murine counterpart of the HD gene might lie between Hx and Emv-1 or D4S43h. Cloning of the region between these markers could generate new probes for conserved human sequences in the vicinity of the HD gene or possibly candidates for the murine counterpart of this human disease locus.     

用生物发光法对绿浓杆菌粘附因子的研究

A bioluminescence method was established for quantifying the adhesion of P. aeruginosa to polystyrene and the adherent components were investigated. The results indicated that the slime polysaccharide (SPS) is an important adherent factor of some slime strains of P. aeruginosa. The adhered amount of washed slime strains could be increased by pre-coating of polystyrene with SPS obtained from PA3. The activity of PA3SPS could be inhibited by anti-PA3SPS antiserum and blocked by N-acetylglucosamine.     

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)     

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.