Evaluation of an anti-inflammatory factor derived from hyperimmunized cows

An anti-inflammatory factor isolated from milk of hyperimmunized cows was analyzed in vitro and in vivo. Macrophages collected from lacteal secretions of a unimmunized nonlactating cow showed increased ability to kill phagocytosed Staphylococcus aureus when incubated with the anti-inflammatory factor. Mice injected intraperitoneally with 10 mg/kg of anti-inflammatory factor demonstrated an increased LD50 to S. aureus when challenged intraperitoneally. Injected mice also demonstrated significantly (P less than 0.05) less mammary inflammation and involution and increased clearance of S. aureus when challenged intramammarily. Quantitative histologic analysis of mammary tissues from mice injected with anti-inflammatory factor demonstrated significantly (P less than 0.05) more lumen, less interalveolar connective tissue, and less leukocytic infiltration compared with control mice. Mammary glands of mice injected with anti-inflammatory factor and challenged with S. aureus also contained fewer colony-forming units than control mice. The product appeared to exert its effect on the nonspecific defense system via modulation of leukocyte function.     

Cilia on bovine mammary epithelium: ultrastructural observations

Ultrastructural examination of bovine mammary tissues revealed the presence of 9+0 or primary cilia protruding from surfaces of alveolar epithelial and myoepithelial cells. Cilia of epithelial cells protruded approximately 1200 nm into lumina of alveoli and arose from a basal body centriole, the associated centriole of the diplosome, and an accessory rootlet system. Cilia on epithelial cells were more frequently observed than cilia on myoepithelial cells. Occasional cilia made contact with macrophages in the alveolar lumen. The structures were more commonly found in tissues from nonlactating cows, and most were observed in the ventral portion of the mammary gland.     

Stability of the larvicidal activity of Bacillus thuringiensis subsp. israelensis: amino acid modification and denaturants.

The Bacillus thuringiensis subsp. israelensis mosquito larvicidal toxin is not a sulfhydryl-activated toxin. The protein disulfide bonds were cleaved and blocked without loss of toxicity. In contrast, modification of the lysine side chains eliminated toxicity. Additionally, the toxin was resistant to high concentrations of salt (8 M NaBr), organic solvents (40% methanol), denaturants (4 M urea), and neutral detergents (10% Triton X-100). However, it was inactivated by both positively and negatively charged detergents and by guanidine hydrochloride.     

Calmodulin levels in the yeast and mycelial phases of Ceratocystis ulmi.

The calmodulin content of the yeast and mycelial phases of Ceratocystis ulmi was determined by radioimmunoassay. Calmodulin levels increased at the G1-S boundary of the cell cycle, coinciding with the first visible appearance of buds or germ tubes. However, in both phases the cellular calmodulin levels were equivalent. No differential synthesis was observed.     

Maintenance of the cellobiose utilization genes of Escherichia coli in a cryptic state

The genes for cellobiose utilization are normally cryptic in Escherichia coli. The cellobiose system was used as a model to understand the process by which silent genes are maintained in microbial populations. Previously reported was (1) the isolation of a mutant strain that expresses the cellobiose-utilization (Cel) genes and (2) that expression of those genes allows utilization of three beta- glucoside sugars: cellobiose, arbutin, and salicin. The Cel gene cluster has now been cloned from that mutant strain. In the course of locating the Cel genes within the cloned DNA segment, it was discovered that inactivation of the Cel-encoded hydrolase rendered the host strain sensitive to all three beta-glucosides as potent inhibitors. This sensitivity arises from the accumulation of the phosphorylated beta- glucosides. Because even the fully active genes conferred some degree of beta-glucoside sensitivity, the effects of cellobiose on a series of five Cel+ mutants of independent origin were investigated. Although each of those strains utilizes cellobiose as a sole carbon and energy source, cellobiose also acts as a potent inhibitor that reduces the growth rate on glycerol 2.5-16.5-fold. On the other hand, wild-type strains that cannot utilize cellobiose are not inhibited. The observation that the same compound can serve either as a nutrient or as an inhibitor suggests that, under most conditions in which cellobiose will be present together with other resources, there is a strong selective advantage to having the cryptic (Cel0) allele. In those environments in which cellobiose is the sole, or the best, resource, mutants that express the genes (Cel+) will have a strong selective advantage. It is suggested that temporal alternation between these two conditions is a major factor in the maintenance of these genes in E. coli populations. This alternation of environments and fitnesses was predicted by the model for cryptic-gene maintenance that was previously published.      

A collection of maize from Darien,Panama

A collection of maize obtained from the Chocó Indian tribe of Darien, Panama, differs from published accounts of maize reported as typical for the area in size and in methods of cultivation. The collection may represent a segregating population from crosses occurring between the racesChococeño andCoastal Tropical Flint. Implications of this hypothesis with regard to problems of introduction, present geographical occurrence, and transportation of these races by nomadic human vectors are briefly discussed.     

Interphotoreceptor retinoid-binding protein. Gene characterization, protein repeat structure, and its evolution

The gene for bovine interphotoreceptor retinoid-binding protein (IRBP) has been cloned, and its nucleotide sequence has been determined. The IRBP gene is about 11.6 kilobase pairs (kb) and contains four exons and three introns. It transcribed into a large mRNA of approximately 6.4 kb and translated into a large protein of 145,000 daltons. To prove the identity of the genomic clone, we determined the protein sequence of several tryptic and cyanogen bromide fragments of purified bovine IRBP protein and localized them in the protein predicted from its nucleotide sequence. There is a 4-fold repeat structure in the protein sequence with 30-40% sequence identity and many conservative substitutions between any two of the four protein repeats. The third and fourth repeats are the most similar pair. All three of the introns in the IRBP gene fall in the fourth protein repeat. Two of the exons, the first and the fourth, are large, 3173 and 2447 bases, respectively. The introns are each about 1.5-2.2 kb long. The human IRBP gene has a sequence that is similar to one of the introns from the bovine gene. The unexpected gene structure and protein repeat structure in the bovine gene lead us to propose a model for the evolution of the IRBP gene.