Two Additional Salmonella Serotypes: Salmonella enteritidis Ser 58:a:- and Salmonella enteritidis Ser 44Z36, Z38:-

The antigenic compositions of two additional Salmonella serotypes isolated from the feces of man were determined to be 58:a:- and 44:Z(36), Z(38)-.     

Effect of Phenolic Acids and Esters on Respiration and Reproduction of Bacteria in Urine

Vanillic, syringic, gallic, and protocatechuic acids, methyl-p-hydroxybenzoate, and propyl-p-hydroxybenzoate generally inhibited respiration in vitro of Escherichia coli, Proteus vulgaris, Pseudomonas aeruginosa, and Aerobacter aerogenes in human urine. In the absence of any other available carbon source, certain of the phenolic compounds were utilized. Reproduction was generally suppressed in urine buffered to pH 7, 5.6, 4.5, and 4.0. The phenolic compounds were used in the range of 0.11 to 0.99 μmole/ml.     

Stimulation of poly-β-hydroxybutyrate oxidation in Sphaerotilus discophorus by manganese and magnesium

Summary When grown with glucose, S. discophorus synthesized large amounts of poly--hydroxybutyrate which accumulated intracellularly as sudanophilic granules. The rate of endogenous oxygen consumption by such cells was markedly increased by Mn⁺⁺ and even more by Mg⁺⁺. It has been shown that these inorganic ions stimulate the oxidation of the intracellular poly--hydroxybutyrate.Dedicated by the senior author to Prof. C. B. van Niel on the occasion of his 70th birthday with gratitude for many unforgettable years of association, instruction and stimulation.     

Accuracy of pulse oximetry to estimate HbO2 fraction of total Hb during exercise

The accuracy of two pulse oximeters (Ohmeda 3700 and Biox IIa) was evaluated during cycle ergometer incremental exercise in 10 healthy subjects. The exercise protocol began at 30 W with the power output being increased 15 W.min-1 until volitional fatigue. Ear and finger probe pulse oximetry measurements of available hemoglobin (%Spo2) were compared with arterial oxyhemoglobin fraction of total hemoglobin (%HbO2) measured directly from arterial blood samples using a CO-oximeter. To provide a wide range of %HbO2 values, four subjects exercised under hypoxic conditions [inspired partial pressure of O2 (PIo2) = 107 Torr], while the remaining six subjects exercised under normoxic conditions (PIo2 = 150 Torr). Because carboxyhemoglobin (HbCO) or methemoglobin (MetHb) is not measured by pulse oximeters, %HbO2 was corrected for HbCO and MetHb and expressed as percent arterial O2 saturation of available Hb (%Sao2). Small and insignificant differences (P greater than 0.05) existed between SpO2 (all 3 instruments) and %SaO2 at the lowest work rate and the highest power output achieved. Regression analyses of %SpO2 vs. %SaO2 produced correlation coefficients of r = 0.82 [standard error of the estimate [(SEE) = 1.79], r = 0.89 (SEE = 1.48), and r = 0.93 (SEE = 1.14) for the Biox IIa, Ohmeda 3700 (ear), and the Ohmeda 3700 (finger) pulse oximeters, respectively. We conclude that pulse oximetry, within the above limits of accuracy, is useful in estimating %SaO2 during exercise in healthy subjects.     

Photoperiodic influences on sexual behavior in male Syrian hamsters

The effect of photoperiodic conditions on sexual behavior was investigated in male Syrian hamsters that were either gonadally intact, or castrated and treated with low doses of testosterone throughout the experiment. Hamsters were exposed to long (LD 16:8) or short (LD 8:16) days for 7 weeks; for the next 8 weeks, either they were exposed to an intermediate daylength (LD 12:12), or daylength conditions remained unchanged. Sexual behavior was affected by photoperiod conditions in both gonadally intact animals and testosterone-treated castrates, but to different degrees. Intact males exposed to short days for 15 weeks exhibited gonadal regression, and their copulatory performance was impaired. The percentage of animals that intromitted or ejaculated was significantly reduced. Additional measures of sexual performance among the copulating males were also affected. In contrast, among the castrates with testosterone clamped at low but stable levels, the proportion of males that mounted, intromitted, or ejaculated was not affected by photoperiod. However, among the males that continued to copulate, sexual performance changes were present in the short-day castrates that resembled those displayed by the intact males. We infer that these behavioral effects in both hormonal conditions reflect primarily a difficulty in the attainment of intromission. Gonadal regression alone cannot easily account for the behavioral deficits of the intact males, because circulating testosterone levels at the end of the experiment were not significantly different between the gonadally intact hamsters and the castrated, testosterone-treated hamsters exposed continuously to short days. Males transferred from either long or short days to the intermediate-daylength condition responded behaviorally to this photoperiod as if it were a short day, that is, their ejaculatory frequency declined. We conclude that male hamsters exposed to photoinhibitory daylengths exhibit deficits in their sexual behavior, not only because endogenous levels of testosterone decrease, but also because the substrates on which this hormone acts become less responsive. We hypothesize that under physiological conditions, the episodic secretion of testosterone imposes constraints on the maintenance or restoration of copulation, and that the potent behavioral effects achieved by constant-release implants of testosterone may mask the presence of photoperiodically induced alterations in the hamster's sensitivity to this gonadal hormone.     

Differential effects of testosterone and dibutyryl cyclic AMP on the meiotic maturation of mouse oocytes in vitro

Fully grown, meiotically immature mouse oocytes were isolated and cultured under varying conditions with the aim of determining a) whether the inhibitory effects of testosterone on oocyte meiotic maturation require the synthesis of new oocyte proteins and b) if the meiosis-inhibiting effects of testosterone and dibutyryl cyclic AMP (dbcAMP) are distinct and can be differentiated. We found that the inclusion of puromycin in culture medium containing testosterone has no effect on the meiosis-inhibiting potency of testosterone or upon the reversibility of testosterone effects. We conclude that testosterone inhibits oocyte meiosis by a mechanism that is independent of protein synthesis. We also found that oocytes exposed to testosterone recover more rapidly, as evidenced by the timing of germinal vesicle breakdown (GVBD) following placement in a control medium, than do oocytes exposed to dbcAMP. Through further investigation of this phenomenon we have determined the sequence of testosterone and dbcAMP effects relative to the time course of GVBD. A testosterone-sensitive event occurs 20 min prior to GVBD, while the dbcAMP-sensitive event precedes GVBD by 41 min. The nature of this difference may involve the differential interaction of testosterone and dbcAMP with a set of puromycin-sensitive proteins that are required for GVBD. When oocytes were initially cultured in medium containing both puromycin and either testosterone or dbcAMP and then moved to medium containing puromycin alone the incidence of GVBD was reduced relative to oocytes never exposed to puromycin. This observation suggests that mouse oocytes contain proteins that are required for GVBD and that experience a high turnover rate. The degree of reduction in GVBD was a function of the length of puromycin exposure and was significantly greater in dbcAMP- than in testosterone-exposed oocytes. If oocytes were initially cultured in medium containing puromycin and dbcAMP, the rate of GVBD upon removal of dbcAMP was initially slow but increased with time. This observation is consistent with the hypothesis that dbcAMP inhibits oocytes at a point prior to the functioning of the puromycin-sensitive proteins. However, if oocytes were cultured in medium containing puromycin and testosterone the rate of GVBD following testosterone removal was not significantly reduced relative to oocytes that were not exposed to puromycin. This observation suggests that testosterone acts to inhibit meiosis at a site beyond the function of the puromycin-sensitive proteins or that testosterone causes a reduction in the turnover rate of these proteins.(ABSTRACT TRUNCATED AT 400 WORDS)     

On the regulation of the mitochondrial inner membrane anion channel by magnesium and protons

The inner membrane of mitochondria possesses a pH-regulated anion uniporter which is activated by depletion of matrix divalent cations with A23187 (Beavis, A. D., and Garlid, K. D. (1987) J. Biol. Chem. 262, 15085-15093). It is now shown that Cl- transport through this pathway is inhibited by Mg2+ and Ca2+. There appear to be two sites for inhibition by Mg2+. One has an IC50 = 38 microM at pH 7.4 and appears to be on the inside since it is only observed in the presence of A23187 (10 nmol/mg). The other has an IC50 = 440 microM at pH 7.4 and appears to be on the outside since it is observed in mitochondria pretreated with very low doses of A23187 (0.25 nmol/mg or less) and in A23187-pretreated mitochondria washed to remove A23187. Ca2+ is found to inhibit anion uniport in the presence or absence of A23187 with an IC50 of about 17 microM. In contrast to these findings Cl- uniport, activated by addition of valinomycin to respiring mitochondria without depleting endogenous Mg2+ is found to be very insensitive to exogenous Mg2+, being inhibited with an IC50 of 3.2 mM. This is explained by examination of the pH dependence of the Mg2+ IC50 in non-respiring mitochondria. The internal IC50 is found to be pH-dependent, rising to about 250 microM at pH 8.4. The external IC50 is also pH-dependent, rising to 2.5 mM or above at pH 8.4. These data are consistent with a model in which Mg2+ can only bind to the protein when it is protonated at a site with a pK of about 6.8 located in the matrix. Thus, both the intrinsic activity of the uniporter and its inhibition by Mg2+ appear to be regulated by matrix protons. This makes the rate of anion uniport much more sensitive to changes in matrix pH which is physiologically advantageous for its proposed role in volume homeostasis.     

A recombination event that redefines the Huntington disease region

We report both a recombination event that places the Huntington disease gene proximal to the marker D4S98 and an extended linkage-disequilibrium study that uses this marker and confirms the existence of disequilibrium between it and the HD locus. We also report the cloning of other sequences in the region around D4S98, including a new polymorphic marker R10 and conserved sequences that identify a gene in the region of interest.     

1H and 51V NMR studies of the interaction of vanadate and 2-vanadio-3-phosphoglycerate with phosphoglycerate mutase.

The formation of complexes of vanadate with 2-phosphoglycerate and 3-phosphoglycerate have been studied using 51V nuclear magnetic resonance spectroscopy. Signals attributed to two 2,3-diphosphoglycerate analogues, 2-vanadio-3-phosphoglycerate and 2-phospho-3-vanadioglycerate, were detected but were not fully resolved from signals of inorganic vanadate and the anhydride formed between vanadate and the phosphate ester moieties of the individual phosphoglycerates. Equilibrium constants for formation of the two 2,3-bisphosphate analogues were estimated as 2.5 M-1 for 2-vanadio-3-phosphoglycerate and 0.2 M-1 for 2-phospho-3-vanadioglycerate. The results of the binding study are fully consistent with non-cooperativity in the binding of vanadiophosphoglycerate to the two active sites of phosphoglycerate mutase (PGM). 2-Vanadio-3-phosphoglycerate was found to bind to the dephospho form of phosphoglycerate mutase with a dissociation constant of about 1 x 10(-11) M at pH 7 and 7 x 10(-11) M at pH 8. Three signals attributed to histidine residues were observed in the 1H NMR spectrum of phosphoglycerate mutase. Two of these signals and also an additional signal, tentatively attributed to a tryptophan, underwent a chemical shift change when the vanadiophosphoglycerate complex was bound to the enzyme. The results obtained here are in accord with these vanadate-phosphoglycerate complexes being much more potent inhibitors of phosphoglycerate mutase than either monomeric or dimeric vanadate. The dissociation constant of 10(-11) M for 2-vanadio-3-phosphoglycerate is about 4 orders of magnitude smaller than the Km for PGM, a result in accordance with the vanadiophosphoglycerates being transition state analogues for the phosphorylation of PGM by 2,3-diphosphoglycerate.(ABSTRACT TRUNCATED AT 250 WORDS)     

1H, 15N, 13C, and 13CO assignments of human interleukin-4 using three-dimensional double- and triple-resonance heteronuclear magnetic resonance spectroscopy.

The assignment of the 1H, 15N, 13CO, and 13C resonances of recombinant human interleukin-4 (IL-4), a protein of 133 residues and molecular mass of 15.4 kDa, is presented based on a series of 11 three-dimensional (3D) double- and triple-resonance heteronuclear NMR experiments. These studies employ uniformly labeled 15N- and 15N/13C-labeled IL-4 with an isotope incorporation of greater than 95% for the protein expressed in yeast. Five independent sequential connectivity pathways via one-, two-, and three-bond heteronuclear J couplings are exploited to obtain unambiguous sequential assignments. Specifically, CO(i)-N(i + 1),NH(i + 1) correlations are observed in the HNCO experiment, the C alpha H(i), C alpha (i)-N(i + 1) correlations in the HCA(CO)N experiment, the C alpha(i)-N(i + 1),NH(i + 1) correlations in the HNCA and HN(CO)CA experiments, the C alpha H(i)-N(i + 1),NH(i + 1) correlations in the H(CA)NH and HN(CO)HB experiments, and the C beta H(i)-N(i + 1),NH(i + 1) correlations in the HN(CO)HB experiments. The backbone intraresidue C alpha H(i)-15N(i)-NH(i) correlations are provided by the 15N-edited Hartmann-Hahn (HOHAHA) and H(CA)NH experiments, the C beta H(i)-15N(i)-NH(i) correlations by the 15N-edited HOHAHA and HNHB experiments, the 13C alpha(i)-15N(i)-NH(i) correlations by the HNCA experiment, and the C alpha H(i)-13C alpha(i)-13CO(i) correlations by the HCACO experiment. Aliphatic side-chain spin systems are assigned by 3D 1H-13C-13C-1H correlated (HCCH-COSY) and total correlated (HCCH-TOCSY) spectroscopy. Because of the high resolution afforded by these experiments, as well as the availability of multiple sequential connectivity pathways, ambiguities associated with the limited chemical shift dispersion associated with helical proteins are readily resolved. Further, in the majority of cases (88%), four or more sequential correlations are observed between successive residues. Consequently, the interpretation of these experiments readily lends itself to semiautomated analysis which significantly simplifies and speeds up the assignment process. The assignments presented in this paper provide the essential basis for studies aimed at determining the high-resolution three-dimensional structure of IL-4 in solution.