Confirmatory identification of Neisseria gonorrhoeae by slide coagglutination

Neisseria gonorrhoeae was identified by the Phadebact gonococcus test, a rapid slide coagglutination technique, and the results obtained were compared with those obtained by conventional methods (Gram stain morphology, oxidase reaction, and carbohydrate utilization tests) for the confirmatory identification of gonococci. Of 308 clinical isolates examined, the coagglutination procedure correctly identified 97.8% of the isolates tested as N. gonorrhoeae and 93.9% of other bacteria as not N. gonorrhoeae. The coagglutination procedure also identified 29 laboratory strains correctly as not N. gonorrhoeae. The slide coagglutination test is easy to perform and offers a valuable alternative to other techniques for the confirmatory identification of N. gonorrhoeae.     

The relationship of the oestrogen and progestin receptors in the abnormal uterus of the adult anovulatory rat. Effects of neonatal treatment with testosterone propionate or clomiphene citrate.

The neonatal administration of testosterone propionate to Wistar rats resulted in anovulatory adults in persistent vaginal oestrus. Clomiphene citrate had a similar effect. In both groups of adults, hyperplasia of the uterine epithelium and occasional metaplasia was observed. The uterine nuclear and cytosol oestrogen and progestin receptors of these anovulatory rats were found to have affinities for their respective ligands similar to those of normal females. The nuclear oestrogen receptor comprised occupied and unoccupied components, as in normal females. The content of the nuclear oestrogen receptor was comparable with that of females in the late dioestrous or pro-oestrous phase. This content was higher in the clomiphene-treated group. Despite the relatively high nuclear oestrogen receptor content the content of progestin receptors, a putative index of the oestrogenic response, was lower in the treated rats than in normal adult females throughout the cycle. Administration of oestradiol to both treatment groups resulted in depletion of cytosol oestrogen receptor content 1 h later, which, however, was not reflected by an increase in the content of nuclear oestrogen receptors. There was no measurable increase in progesterone receptor content in treated rats after daily administration of oestrogen (5 microgram/rat) for 3 days. These changes in sex-hormone-receptor interactions involving an impairment of the normal oestrogenic response may be associated with the abnormal differentiation of the uterus in these sterile, anovulatory animals.     

Formaldehyde incorporation by a new methylotroph (L3)

A number of bacterial strains have been isolated and investigated in our search for a promising organism in the production of single-cell protein from methanol. Strain L3 among these isolates was identified as an obligate methylotroph which grew only on methanol and formaldehyde as the sole sources of carbon and energy. The organism also grew well in batch and chemostat mixed-substrate cultures containing methanol, formaldehyde, and formate. Although formate was not utilized as a sole carbon and energy source, it was readily taken up and oxidized by either formaldehyde- or methanol-grown cells. The organism incorporated carbon by means of the ribulose monophosphate pathway when growing on either methanol, formaldehyde, or various mixtures of C1 compounds. Its C1-oxidation enzymes included phenazine methosulfate-linked methanol and formaldehyde dehydrogenase and a nicotinamide adenine dinucleotide-linked formate dehydrogenase. Identical inhibition by formaldehyde of the first two dehydrogenases suggested that they are actually the same enzyme. The organism had a rapid growth rate, a high cell yield in the chemostat, a high protein content, and a favorable amino acid distribution for use as a source of single-cell protein. Of special interest was the ability of the organism to utilize formaldehyde via the ribulose monophosphate cycle.     

Immunohistochemical distribution of MAM-3 and MAM-6 antigens in developing salivary glands of the human fetus

Summary The immunohistochemical expression of MAM-3 and MAM-6 antigens was studied in developing human fetal salivary gland removed at autopsy of 22 normal fetuses of varying maturity (10–40 weeks of gestation). The onset of functional maturation in the fetal gland was seen at 21 weeks of gestational maturity. The acini and ducts then underwent distinct alterations in antigen expression with growth and maturation until the late developmental stage (33–40 weeks of gestation) when they resemble the adult salivary gland. The role of maturing duct cells in histogenesis of salivary gland tumours is discussed.     

Acetic acid formation in Escherichia coli fermentation

Theoretical analysis of cellulase product inhibition (by cellobiose and glucose) has been performed in terms of the mathematical model for enzymatic cellulose hydrolysis. The analysis showed that even in those cases when consideration of multienzyme cellulase system as one enzyme (cellulase) or two enzymes (cellulase and beta-glucosidase) is valid, double-reciprocal plots, usually used in a product inhibition study, may be nonlinear, and different inhibition patterns (noncompetitive, competitive, or mixed type) may be observed. Inhibition pattern depends on the cellulase binding constant, enzyme concentration, maximum adsorption of the enzyme (cellulose surface area accessible to the enzyme), the range in which substrate concentration is varied, and beta-glucosidase activity. A limitation of cellulase adsorption by cellulose surface area that may occur at high enzyme/substrate ratio is the main reason for nonlinearity of double-reciprocal plots. Also, the results of calculations showed that material balance by substrate, which is usually neglected by researchers studying cellulase product inhibition, must be taken into account in kinetic analysis even in those cases when the enzyme concentration is rather low. (c) 1992 John Wiley & Sons, Inc.     

Induction of responsiveness of rat diaphragm to ovine growth hormone after administration of reserpine.

The diaphragm of the pituitary intact rat is insensitive to the insulin-like effects of growth hormone unless weanling animals are used, and even then these effects are not achieved reliably. We report here that an intraperitoneal injection of reserpine is able to induce consistent responsiveness to ovine growth horomone (oGH) in hemidiaphragms from 20-27 day old rats as assessed by stimulation of 3H-AIB transport and 14C-phenylalanine incorporation into protein. Maximal stimulation of 3H-AIB transport (approximately 40%) can be elicited by addition of oGH (5 micrograms/ml) to hemidiaphragms after a 2 mg/kg injection of reserpine given 5 h prior to sacrifice. The degree of stimulation does not alter significantly if the rats are sacrificed 3, 5 or 12 h after administration of reserpine, although it decreases by 24 h. Administration of reserpine 3 h before sacrifice also leads to a 50% increase in 14C-phenylalanine incorporation into protein in rat diaphragms in response to the addition of oGH (5 micrograms/ml). The induced sensitivity to oGH is not due to inhibition of GH secretion by reserpine as demonstrated by RIA of plasma GH. Addition of a monoclonal antibody to the GH receptor (MAb263) did not result in a stimulation or inhibition of 3H-AIB uptake or stimulation of protein synthesis in reserpinized rat hemidiaphragms. These results suggest that reserpine can induce tissue responsiveness in rats 20-27 d.o. independent of plasma GH levels. Our results also imply that the type 1 GH receptor of Barnard, Bundesen, Rylatt and Waters (1985) does not mediate the insulin like actions of GH on rat diaphragm.     

The binding of rat uterine cytosol oestrogen receptors to oligodeoxythymidylate--cellulose. Its relationship to a stable form of receptor complex with separate ligand- and oligonucleotide-binding sites.

The interaction of rat uterine cytosol oestrogen-receptor complexes with the synthetic acceptor oligo(dT)--cellulose was studied. Differences in the stability of receptor complexes and their ability to bind to oligo(dT)--cellulose on storage at 4 degrees C or when exposed to increased temperatures indicated heterogeneity of steroid- and oligonucleotide-binding sites. Dilution, dialysis and (NH4)2SO4 precipitation increased the interaction of receptor complexes with oligo(dT)--cellulose (a step termed activation). This increase may be the result of the removal of low-molecular-weight cytosol components which inhibit receptor activation, dimerization to the 5 S form, which binds to oligo(dT)--cellulose, or interaction of 5 S receptor with the oligonucleotide. Cytosol oestradiol--receptor complexes exhibited biphasic dissociation kinetics. All these manipulations resulted in an increase in the proportion of the slow-dissociating component equivalent to the increase in receptor binding to oligo(dT)--cellulose. In contrast, addition of 10mM-sodium molybdate to cytosol decreased both oligo(dT)--cellulose binding and the proportion of receptor with slow dissociation kinetics. The inclusion of proteinase inhibitors did not affect interactions of receptor with oligo(dT)--cellulose nor the dissociation kinetics. These results suggest that oligo(dT)--cellulose binding may serve to quantify the proportion of cytosol receptor in an active form capable of nuclear interaction and to help to ascertain whether a receptor system is fully functional. This binding procedure could prove useful in the evaluation of oestrogen responsivity under normal and pathological conditions.     

The polyadenylated RNA directing the synthesis of the rat myelin basic proteins is present in both free and membrane-bound forebrain polyribosomes.

Free and membrane-bound polyribosomes were isolated from the forebrain of actively myelinating 24-day-old rats. The poly(A)+ RNA (polyadenylated RNA) extracted from both fractions was translated in vitro in reticulocyte lysates [Hall & Lim (1981) Biochem. J. 196. 327-336] in the presence or absence of a heterologous microsomal membrane fraction from dog pancreas. The rat myelin basic proteins synthesized in vitro were isolated by CM-cellulose chromatography and by immunoprecipitation with purified anti-(myelin basic protein) antibody. The large (mol.wt. 18 500) and small (mol.wt. 16 000) myelin basic proteins were translational products of poly(A)+ RNA from both free and membrane-bound polyribosomes. The identity of the myelin basic proteins was verified by analysis of peptides generated by the cathepsin D digestion of the immunoprecipitated proteins synthesized in vitro, in comparison with authentic rat myelin basic proteins. Although several other translational products of membrane-bound polyribosomal poly(A)+ RNA were modified when microsomal membranes were present during translation, molecular weights of the myelin basic proteins themselves were unchanged. The myelin basic proteins synthesized in vitro also did not differ significantly in size from the authentic myelin basic proteins, indicating that these membrane proteins are unlikely to be synthesized as substantially larger precursor molecules. The presence of the specific mRNA species on both free and membrane-bound polyribosomes is compatible with the extrinsic location of the myelin basic proteins on the cytoplasmic surface of the myelin membrane.     

Magnitude of colonization and sepsis by group B streptococci in newborn infants

Infants admitted to the Neonatal Intensive Care Unit at Tampa General Hospital, Tampa, Florida, were cultured for group B streptococci (GBS). Culture swabs were quantified for GBS to determine the magnitude of colonization in infected infants. Thirty-seven (17%) of the 217 infants cultured were positive for GBS. Six of these colonized infants developed sepsis, with blood cultures positive for GBS. Septic infants generally were colonized by large numbers of GBS (10⁵ bacteria/culture swab) at two or more external skin sites, in comparison to aseptic infants, who were lightly colonized with GBS. The data suggest a possible correlation between magnitude of colonization by GBS at external skin sites and development of GBS sepsis in newborn infants.