Incorporation of N-acetyl-D-glucosamine from UDP-N-acetyl-D-glucosamine by isolated membranes of Bacillus subtilis. Identification of undecaprenyl poly(N-acetylglucosaminyl pyrophosphate).

Membrane isolated from Bacillus subtilis strain 168 incorporated GlcNAc from UDP-GlcNAc directly onto undecaprenyl phosphate via transphosphorylation and subsequent transglucosylations. Chain lengths of 6, 4, and 1 units of GlcNAc were found. Approximately 80% of the isotope incorporated was extracted into chloroform:methanol (2:1 v/v), and could be distinguished from the undecaprenyl disaccharide cell wall intermediate by a different elution pattern on DEAE-cellulose (acetate form). The GlcNAc-lipid(s) were eluted from a similar column in chloroform:methanol:water (10:10:3, v/v) with 6 mM NH4COOH indicating a pyrophosphate linkage between the lipid and the GlcNAc. The GlcNAc-lipid(s) were not degraded by conditions which completely deacylated [32P]glyceryl phospholipids, but were rapidly hydrolyzed by mild acid treatment (0.005 N HCl, 90 degrees) with the release of oligosaccharide phosphate (typical of sugars linked to undecaprenyl pyrophosphate). Catalytic hydrogenation of the GlcNAc-lipid(s) resulted in the release of water-soluble sugar phosphate. Under these same conditions, undecaprenyl pyrophosphate and undecaprenyl disaccharide cell wall intermediate were similarly effected while [32P]glyceryl phospholipids remained intact. The formation of GlcNAc-lipid(s) in vitro was inhibited if membranes were prepared from cells previously treated with bacitracin. Thus, the GlcNAc-lipid(s) has the properties of undecaprenyl poly(N-acetylglucosaminyl pyrophosphate) and may represent a new synthetic role of the polyisoprenyl lipid in B. subtilis.     

Poliovirus aggregates and their survival in water.

Inactivation of aggregated poliovirus by bromine is characterized by a continuously decreasing reaction rate. Poliovirus released from infected cells in these experiments by alternate freezing and thawing in water without electrolytes has always been aggregated. The aggregates persist even on 7,000-fold dilution in ion-free water. Virus similarly released into phosphate-buffered saline solution may be well dispersed, but it aggregates when sedimented into a salt-free sucrose gradient or when it is diluted as little as 10-fold in water. Large one-step dilutions of dispersed virus in water remain dispersed. Aggregated virus was not dispersed by one-step dilution (7,000-fold) in distilled or untreated lake water but was dispersed if phosphate-buffered saline or clarified secondary sewage plant effluent was used as diluent. Dispersed virus aggregates at all dilutions in alum-treated, finished water from the city filter plant. This may be the result of complex formation with insoluble material rather than virion-virion aggregation. A simple procedure is described for rendering a very dilute suspension of mixed virion aggregates into a three-part spectrum of sizes.     

Aerobic respiration in mutants of Escherichia coli accumulating quinone analogues of ubiquinone.

The ability of three naturally occurring analogues of ubiquinone to function in aerobic respiration in Escherichia coli has been studied. The compounds, which differ from ubiquinone in terms of the substituents on the quinone ring, accumulate in the cytoplasmic membranes of ubiE-, ubiF- and ubiG- mutants. One of the analogues (2-octaprenyl-3-methyl-6-methoxy-1,4-benzoquinone, NMQ), which lacks the 5-methoxyl group of the benzoquinone ring of ubiquinone promoted the oxidation of NADH, D-lactate and alpha-glycerophosphate but not succinate. Electron transport supported by MMQ was found to be coupled to phosphorylation. In contrast, 2-octaprenyl-6-methoxy-1,4-benzoquinone, which lacks both the 3-methyl and 5-methoxyl groups of ubiquinone, and 2-octaprenyl-3-methyl-5-hydroxy-6-methoxy-1,4-benzoquinone, in which the 5-methoxyl group of ubiquinone is replaced by an hydroxyl group, were virtually inactive in the oxidases tested. The ability of MMQ to function in respiration in isolated membranes is consistent with the findings that the growth rate and yield of a ubiF- strain, unlike other ubi- strains, were only slightly lower than those of a ubiF+ strain. The fact that MMQ is active in some but not all oxidases provides further support for the concept that the quinones link the individual dehydrogenases to the respiratory chain and that each dehydrogenase has specific structural requirements for quinone acceptors.     

The effect of phenylephrine on excretion of fluid and electrolytes by the parotid and mandibular glands of the rat

The effect has been investigated of the alpha-adrenergic agonist, phenylephrine, on excretion of water and electrolytes (Na, K, and HCO3) by the parotid and mandibular glands of the rat. In the mandibular glands the agonist was as effective as acetylcholine (or parasympathetic nerve stimulation) in stimulating secretion, and the electrolyte excretory patterns seen in the two modes of stimulation were similar. In the parotid gland, phenylephrine was only one-fifth as potent as acetylcholine (or parasympathetic nerve stimulation) in evoking a secretory response but, when due allowance for flow rate differences is made, the electrolyte excretion patterns were similar. In both glands the secretory response to phenylephrine was totally different, in magnitude and in electrolyte excretion pattern, to that evoked by the beta-adrenergic agonist, isoprenaline. It is concluded, as has already been established for secretion of exportable protein, that alpha-adrenergic agonists have very similar effects to muscarinic agonists both on endpiece and on duct cells and that these actions are completely different from those evoked by activation of beta-adrenergic receptors.     

Reduction of lactic acid secreted from SV3T3 cells by a serum factor and biotin and its relationship to cell growth

Supplementation of media containing a low concentration (0.15–0.30% $\text{v}\text{>v}$) of calf serum with biotin or a low molecular weight serum growth factor (Peak III) reduces the amount of lactic acid secreted by simian virus 40-transformed 3T3 cells. While biotin and Peak III (which has been tentatively identified as biotin) can stimulate “stationary phase” cells to resume viable cell division, this growth promotion is not due to an alleviation of lactic acid toxicity per se. This conclusion is based on the finding that, although higher concentrations of lactic acid are cytotoxic, lactic acid added at concentrations found during “stationary phase” to cells plated in fresh medium is not growth inhibitory. These results suggest, instead, a possible major role for biotin and Peak III in energy production.     

Rallinyssus sorae sp. n. (Acari: Dermanyssidae: rhinonyssinae) from the nasal passages of the sora, Porzana carolina (Aves: Rallidae)

Rallinyssus sorae sp. n. is described from the nasal turbinates of the sora, Porzana carolina, collected in Maryland and Ohio. The new species is most similar to Rallinyssus verheyeni Fain but differs in number of setae on the female ventral opisthosoma, structure of the fixed and movable digits of the male and female chelicerae, chaetotaxy of legs I to IV, and presence of a sternal plate in the male. The taxonomy and host-parasite relationships of the various species of Rallinyssus are discussed.