The concentration of glycine by preparations of the yeast Saccharomyces Carlsbergensis depleted of adenosine triphosphate: Effects of proton gradients and uncoupling agents.

1. At pH 4.5 and 30degreesC, yeast preparations depleted of ATP in the presence of antimycin and deoxyglucose spontaneously lost K+, gaining roughly an equivalent amount of H+. 2. Five proton conductors including azide and 2,4-dinitrophenol accelerated this process, as did [14C]glycine, which was absorbed with two extra equivalents of H+. 3. The rate of glycine uptake at pH 4.5 diminished fourfold when cellular K+ fell by 20%. 4. The distribution of [14C]propionate indicated that the intracellular pH fell from 6.2 to 5.7 when the cellular content of K+ fell by 30%. 5. Glycine uptake from a 5 muM solution was about 400 times faster at pH 4.5 than it was at pH 7.4 with 100mM-KC1 present ostensibly to lower the membrane potential. 6. Yeast preparations containing 2mM-[14C]glycine absorbed a further amount from a 0.1 muM solution at pH 4.5. After about 10 min a net movement of [14C]glycine out of the yeast occurred. The ratio of the cellular [14Ia1glycine concentration to the concentration outside the yeast reached 4 X 10(4) in these assays, whereas at pH 7.4 in the presence of 100mM-KC1 it did not exceed 15 in 3h. Dimitrophenol lowered the accumulation ratio at pH 4.5, apparently by causing proton conduction. 7. The observations are consistent with the notion that glycine uptake is driven by a proton symport mechanism. 8. Possible factors governing the strikingly low rate of glycine efflux as opposed to its optimum rate of influx are discussed.     

Minimization of a sodium dithionite-derived interference in nitrate reductase-methyl viologen reactions

The use of sodium dithionite as the reducing agent to produce the radical cation of methyl viologen cofactor for the nitrate reductase-catalyzed reduction of nitrate to nitrite causes a negative interference in the diazonium salt azo dye determination of nitrite. The interference results from bisulfite, a reaction product of dithionite, reacting with the diazonium salt formed from nitrite and sulfanilamide. Addition of formaldehyde before the diazotization reaction masks this interference but at low acidity introduces a nonlinearity in the nitrite calibration curve. This nonlinearity is due to a competing reaction of formaldehyde with sulfanilamide to yield a Schiff base and can be eliminated by increasing the HCL content of the sulfanilamide reagent.     

Four familial translocations ascertained through spontaneous abortions

Summary In a study of 514 spontaneous abortions, 194 were found to have a chromosome anomaly. Of these, 4 (2.1%) were unbalanced translocations. Three of the translocations were Robertsonian (13q14q) and one was reciprocal. Each translocation was ascertained independently and each was associated with a balanced rearrangement in a carrier parent.     

Calycadenia hooveri (Asteraceae), a new tarweed from California

In accord with its cytological and morphological distinctiveness and its geographical disjunction, the Sierran element ofC. pauciflora A. Gray is described as a new species,C. hooveri. Its chromosome number ofn = 7 is documented for the first time. Evidence from cytogenetic analysis of synthetic hybrids is presented to support the conclusion thatC. hooveri is more closely related toC. villosa DC. than toC. pauciflora. Characteristics of ligule morphology and the distribution of the peculiar saucer-shaped glands on the peduncular and receptacular bracts of these species also support the new interpretation.     

Growth hormone release inhibiting hormone: actions on thyrotrophin and prolactin secretion after thyrotrophinreleasing hormone.

The hypothalamic tetradecapeptide growth hormone release inhibiting hormone (GH-RIH) blocked the thyrotrophin response to thyrotrophin-releasing hormone (TRH) in normal people and in patients with primary hypothyroidism. This inhibition was dose related. The TRH-induced prolactin release was not affected by GH-RIH. This dissociation of the thyrotrophin and prolactin responses to TRH by GH-RIH suggests that there are different mechanisms for release of thyrotrophin and prolactin and that only the former is affected by GH-RIH.     

Postexercise protein supplementation improves health and muscle soreness during basic military training in Marine recruits.

Elevated postexercise amino acid availability has been demonstrated to enhance muscle protein synthesis acutely, but the long-term impact of postexercise protein supplementation on variables such as health, muscle soreness, and function are unclear. Healthy male US Marine recruits from six platoons (US Marine Corps Base, Parris Island, SC; n = 387; 18.9 +/- 0.1 yr, 74.7 +/- 1.1 kg, 13.8 +/- 0.4% body fat) were randomly assigned to three treatments within each platoon. Nutrients supplemented immediately postexercise during the 54-day basic training were either placebo (0 g carbohydrate, 0 g protein, 0 g fat), control (8, 0, 3), or protein supplement (8, 10, 3). Subjects and observers making measurements and data analysis were blinded to subject groupings. Compared with placebo and control groups, the protein-supplemented group had an average of 33% fewer total medical visits, 28% fewer visits due to bacterial/viral infections, 37% fewer visits due to muscle/joint problems, and 83% fewer visits due to heat exhaustion. Recruits experiencing heat exhaustion had greater body mass, lean, fat, and water losses. Muscle soreness immediately postexercise was reduced by protein supplementation vs. placebo and control groups on both days 34 and 54. Postexercise protein supplementation may not only enhance muscle protein deposition but it also has significant potential to positively impact health, muscle soreness, and tissue hydration during prolonged intense exercise training, suggesting a potential therapeutic approach for the prevention of health problems in severely stressed exercising populations.