A study of anti-group A streptococcal monoclonal antibodies cross-reactive with myosin

Anti-group A streptococcal monoclonal antibodies were obtained from BALB c/BYJ mice immunized with purified membranes from M type 5 Streptococcus pyogenes. Two of the anti-streptococcal monoclonal antibodies were previously shown to cross-react with muscle myosin. In this study the monoclonal antibodies were reacted with tissue sections of normal human heart and skeletal muscle. Antibody binding was estimated by indirect immunofluorescence and immunoperoxidase techniques. Both of the monoclonal antibodies (36.2.2 and 54.2.8) investigated in this report reacted with heart and/or skeletal muscle sections. When evaluated by immunofluorescence, monoclonal antibody 54.2.8 demarcated the periphery of cardiac striated muscle cells and reacted to a lesser degree with subsarcolemmal components. Monoclonal antibody 36.2.2 failed to react with heart sections, but both of the monoclonal antibodies reacted strongly with skeletal muscle sections. Results similar to those observed with indirect immunofluorescence were obtained with the immunoperoxidase technique. By Western immunoblotting and competitive inhibition assays, monoclonal antibodies 36.2.2 and 54.2.8 both were found to react with the heavy chain of skeletal muscle myosin. However, only 54.2.8 reacted with the heavy chain of cardiac myosin. The specificity of the monoclonal antibodies for subfragments of skeletal muscle myosin indicated that monoclonal antibody 36.2.2 was specific for light meromyosin fragments, whereas 54.2.8 reacted with both heavy and light meromyosin. The data demonstrated that two monoclonal antibodies against streptococci were specific for skeletal muscle and/or cardiac myosin and for subfragments of the myosin molecule. The reactions of the monoclonal antibodies with human tissue sections were consistent with the immunochemical reactions of the monoclonal antibodies with both denatured and native myosin.     

Evaluation of the control of Myobia musculi infestations on laboratory mice with permethrin

The efficacy of permethrin against Myobia musculi (Schrank) (Acari:Myobiidae) infestations on mice was evaluated using four different dose delivery methods. In all methods, an attempt was made to deliver 0.5 mg of active permethrin weekly to each mouse. Successful control was achieved with topical or environmental treatment with 0.25% permethrin dust and by dipping the mice into a 0.6 g/l permethrin emulsion. The use of an emulsion applied to the bedding produced the least satisfactory control. Untreated mice had an average infestation rate of 57.3% throughout the study. No significant differences were seen between treated and untreated groups in either body weight or histopathology of the liver, lung, or kidney.     

[3H]Indole-3-Acetyl-myo-Inositol Hydrolysis by Extracts of Zea mays L. Vegetative Tissue

[³H]Indole-3-acetyl-myo-inositol was hydrolyzed by buffered extracts of acetone powders prepared from 4 day shoots of dark grown Zea mays L. seedlings. The hydrolytic activity was proportional to the amount of extract added and was linear for up to 6 hours at 37°C. Boiled or alcohol denatured extracts were inactive. Analysis of reaction mixtures by high performance liquid chromatography demonstrated that not all isomers of indole-3-acetyl-myo-inositol were hydrolyzed at the same rate. Buffered extracts of acetone powders were prepared from coleoptiles and mesocotyls. The rates of hydrolysis observed with coleoptile extracts were greater than those observed with mesocotyl extracts. Active extracts also catalyzed the hydrolysis of esterase substrates such as α-naphthyl acetate and the methyl esters of indoleacetic acid and naphthyleneacetic acid. Attempts to purify the indole-3-acetyl-myo-inositol hydrolyzing activity by chromatographic procedures resulted in only slight purification with large losses of activity. Chromatography over hydroxylapatite allowed separation of two enzymically active fractions, one of which catalyzed the hydrolysis of both indole-3-acetyl-myo-inositol and esterase substrates. With the other fraction enzymic hydrolysis of esterase substrates was readily demonstrated, but no hydrolysis of indole-3-acetyl-myo-inositol was ever detected.     

Mutant of Salmonella typhimurium LT2 deficient in DNA adenine methylation.

A mutant of Salmonella typhimurium LT2 deficient in methylation of the adenine residues in the sequence 5'-GATC-3' was isolated. The mutation (dam-1) was linked to the cysG locus, and the properties of the mutant were similar to those of Escherichia coli dam mutants. Reversion of the hisC3076 frameshift marker by 9-aminoacridine was substantially enhanced by the dam-1 mutation, implying a direct role for adenine methylation in the prevention of frameshift mutation induction.     

Plant community structure in relation to grazing and environmental changes along a north-south transect in the western Kalahari

Sixteen vegetation types were described from a north-south transect in the western Kalahari. Pronounced differences were found between communities on the nutrient poor red Kalahari sand, covering most of the area and those on fine soils and white calcareous sand. Syntaxa resulting from severe overgrazing by livestock were in most cases clearly distinguished from the less disturbed vegetation. The communities on red sand consisted mainly of shrub savanna dominated by perennial tufted grasses, whereas in the vegetation on calcareous material and on overgrazed land, forbs, dwarf shrubs and shrubs played a more important role. The major communities on red sand showed a clear geographical zonation roughly corresponding to the gradient in mean annual rainfall and its interannual variation. In the northern and central Kalahari these syntaxa were dominated by species of Sudano-Zambezian origin and in the southern Kalahari by species showing Karoo-Namib affinities.     

Cytochrome b5 promotes the synthesis of delta 16-C19 steroids by homogeneous cytochrome P-450 C21 side-chain cleavage from pig testis

Conversion of progesterone to 17 alpha-hydroxyprogesterone plus androstenedione (17 alpha-hydroxylation) and to androstadienone (delta 16 synthetase activity) by microsomes from neonatal pig testis, were both inhibited by antibodies raised against homogeneous cytochrome P-450 C21 side-chain cleavage. Inhibition of the two activities showed the same relationship to the concentration of antibody added. Analogous results were obtained with pregnenolone as substrate. In a reconstituted enzyme system consisting of the homogeneous cytochrome P-450 C21 side-chain cleavage enzyme, P-450 reductase and NADPH, addition of cytochrome b5 resulted in the synthesis of the corresponding delta 16-C19-steroid from progesterone (androstadienone) and pregnenolone (androstadienol). The effect of cytochrome b5 was concentration-dependent and prevented by anti-cytochrome b5. It is concluded that the cytochrome P-450 C21 side-chain cleavage enzyme from pig testicular microsomes is also capable of synthesizing delta 16-C19-steroids and is, therefore, likely to be responsible for the large amounts of the pherormone androstadienone produced by male pigs.     

Sutural morphogenesis in the mouse calvaria: the role of apoptosis

Sutural morphogenesis was studied in calvariae of fetal and newborn 16- to 26-day postconception C57B1/6J mice. The squamoid pattern characteristic of most calvarial sutures appeared to be established during the phase of approach of the adjacent bone territories as they assumed different ecto/ifendocranial planes within the desmocranium. When this stratification failed, apoptosis, a form of cell death, was seen to occur upon physical contact of the leading osteogenic cells of each heterotopic bone territory. Apoptosis appeared as part of a secondary morphogenetic mechanism preventing physical contact and resultant fusion of adjacent mineralized zones, as well as enhancing appearance of the usual pattern of overlap of calvarial sutures.     

Thymosin fraction 5 causes increased serum corticosterone in rodents in vivo

In these studies it was found that i.p. injection of thymosin fraction 5 (TF5) caused a dose-dependent increase in serum corticosterone in male Swiss Webster mice and in male Wistar rats. The maximum responses were seen at 1 and 2 hr, respectively. There was no effect on serum corticosterone in mice when Thymosin alpha 1 (a 28 amino acid peptide isolated from TF5) was injected i.p. at doses up to 100 micrograms. The steroidogenic effects of TF5 were seen only when the basal levels of serum corticosterone were low (less than 80 ng/ml). In studies in which the baseline levels in the animal colony were elevated (greater than 80 ng/ml), there were no steroidogenic effects, or they were minimal. These results suggest that some component of TF5 may influence pituitary adrenal function.     

Two daily melatonin injections differentially induce nonshivering thermogenesis and gonadal regression in the mouse (Peromyscus leucopus)

Female white-footed mice (Peromyscus leucopus) were injected twice daily with 5, 10, 50, 100 micrograms melatonin (MEL) or saline. Injections were given for 7 weeks at 2 and 12 hours after lights-on under a long day (LD 16:8) photoperiod. Afternoon administration of MEL induced gonadal regression, although a dose of 50 micrograms or more was necessary to obtain a maximal response. A 5 micrograms MEL injection in the afternoon resulted in intermediate reproductive tract weights. In white-footed mice a morning MEL injection did not abolish the reproductive regression induced by an afternoon injection. Mice receiving 10, 50 or 100 micrograms MEL daily exhibited increased nonshivering thermogenesis (NST), irrespective of the timing of the injection. Daily injections of 5 micrograms MEL had little effect on NST. These observations suggest that "up and down regulation" of MEL receptors may not be important in P. leucopus. Further, the mechanism by which MEL controls reproduction is different from that for NST.