Effect of reducing agents on oxidation-reduction potential and the outgrowth of Clostridium botulinum type E spores.

Oxidation-reduction potential (Eh) levels were measured and standardized to pH (Eh7) for Trypticase soy broth containing various concentrations of reducing agents. Prereduced Trypticase soy broth with no added reducing agents exhibited a potential of -141 mV. Ascorbic acid at 0.2 to 0.005% and sodium thioglycolate at concentrations below 0.05% produced an Eh7 higher than the prereduced Trypticase soy broth containing no added reducing agents. The addition of cysteine hydrochloride,2-mercaptoethanol, and sodium formaldehyde sulfoxylate to prereduced Trypticase soy broth resulted in a reduction of Eh7 compared to the system without added reducing agents. The order of relative reducing intensity (from highest to lowest) for the reducing agents when comparing molar concentration was: sodium formaldehyde sulfoxylate,2-mercaptoethanol, cysteine hydrochloride, sodium thioglycolate, and ascorbic acid. Optimal growth of the test organism occurred at low Eh7 and low concentration of the reducing agents. A direct correlation existed between growth of the test organism and -Eh7 x -log concentration of the reducing agent.     

Intracellular glycosidases of human colon Bacteroides ovatus B4-11

Activity of various glycosidases in the intracellular enzyme fraction of Bacteroides ovatus B4-11 was investigated. During 120 h of incubation at 37 degrees C, ca. 30% of the crude hemicellulose was hydrolyzed by an intracellular enzyme fraction of strain B4-11. Xylose was the major sugar released from crude hemicellulose. Glycosidases (alpha-1,6-glucosidase, alpha-1,4-glucosidase, beta-1,4-glucosidase, and beta-1,4-xylosidase) were induced in B. ovatus B4-11 by crude hemicellulose and heteroxylan. When B. ovatus B4-11 was grown on either crude hemicellulose or heteroxylan, the predominant enzyme in the intracellular enzyme fraction was beta-1,4-xylosidase.     

Molecular evolution of the period gene in Drosophila athabasca

We measured nucleotide variability within and between the three semispecies of the Drosophila athabasca complex, at the period (per) gene by using a polymerase chain reaction-based four-cutter restriction- enzyme analysis. The levels of polymorphism varied considerably between the three semispecies. Our results for per, combined with previous data for X-linked allozymes, suggest that the X chromosome in the western- northern semispecies is less variable than expected under an equilibrium-neutral model. Both the pattern of divergence between the semispecies and a cladistic clustering of per haplotypes support the previously hypothesized grouping of eastern A and eastern B as the two most recently diverged semispecies. A 21-bp in-frame segment in the region of per which shares sequence similarity with the neuronal development gene single minded is deleted in all eastern A and eastern B flies examined but is present in all of the western-northern flies and all other published per sequences. Despite these hints that there may be significant differences at the per gene between the semispecies, especially the western-northern group versus the two eastern groups, there is no compelling evidence that per is involved in the mating song differences between the semispecies.      

The partial purification from calf serum of a fraction with multiplication-stimulating activity for chicken fibroblasts in cell culture and with non-suppressible insulin-like activity

A multiplication-stimulating activity for chicken embryo fibroblasts has been purified approximately 6000-fold from calf serum by a three step procedure. The partially purified multiplication-stimulating activity stimulated DNA synthesis, mitosis, and growth of cultured chicken embryo fibroblasts. In addition, the active step 3 material was shown to have non-suppressible insulin-like activity and to be an inhibitor of trypsin activity. The activity appeared to be associated with a small protein and was heat stable, but sensitive to dithiothreitol and to periodate.     

Nucleolin Interacts with the Dengue Virus Capsid Protein and Plays a Role in Formation of Infectious Virus Particles

Dengue virus (DENV) is a mosquito-transmitted flavivirus that can cause severe disease in humans and is considered a reemerging pathogen of significant importance to public health. The DENV capsid (C) protein functions as a structural component of the infectious virion; however, it may have additional functions in the virus replicative cycle. Here, we show that the DENV C protein interacts and colocalizes with the multifunctional host protein nucleolin (NCL). Furthermore, we demonstrate that this interaction can be disrupted by the addition of an NCL binding aptamer (AS1411). Knockdown of NCL with small interfering RNA (siRNA) or treatment of cells with AS1411 results in a significant reduction of viral titers after DENV infection. Western blotting and quantitative RT-PCR (qRT-PCR) analysis revealed no differences in viral RNA or protein levels at early time points postinfection, suggesting a role for NCL in viral morphogenesis. We support this hypothesis by showing that treatment with AS1411 alters the migration characteristics of the viral capsid, as visualized by native electrophoresis. Here, we identify a critical interaction between DENV C protein and NCL that represents a potential new target for the development of antiviral therapeutics.     

Growth and reproduction of the tidepool sculpinOligocottus maculosus

Growth and reproduction of tidepool sculpins (Oligocottus maculosus) from three sites in Puget Sound, Washington State, USA were characterized. One site was a sandy, gently sloping beach, the second was an exposed rock headland with minimal algal cover, and the third was an exposed rock headland with numerous tidepools containing abundant algal cover. Length-weight relationships for sculpins did not differ significantly between sexes within sites. Population age structure, growth rate and recruitment varied among the three study sites using data pooled across both sexes. Young-of-the-year sculpins comprised 91% of the population at the exposed headland site with minimal algal cover but only 6% at the headland with abundant algal cover. Selective predation by great blue herons (Ardea herodias) upon tidepool sculpins larger than 45 mm total length assisted in the maintainance of these age structures. A maximum gonadosomatic index of 28.5 was calculated; this index correlated poorly with either age, length or somatic weight. Diameters of unshed ova from preserved tidepool sculpins sampled prior to spawning fell into three classes. Comparison of the mean egg size of each mode and the number of modes present in preserved sculpins with similar data from tidepool sculpins that spawned in the laboratory suggested that spawning occurred twice yearly from at least January through August.