Inhibition of nitrate reduction in some rumen bacteria by tungstate.

Tungstate prevented the formation of active nitrate reductase in growing rumen bacteria capable of nitrate reduction, but did not directly inhibit the enzyme activity of all strains tested.

[Psycholinguistic aspects of aphasia diagnosis and therapy].

A central goal of psycholinguistic research on the diagnosis and therapy of aphasic patients consists of the construction of a series of language tasks which a. can provide guidelines for the development of systematic therapy programs and b. are suited to the evaluation of the recovery process in aphasia, in particular the effectiveness of speech therapy.

Kinetic parameters of lactate dehydrogenases of some rumen bacterial species, the anaerobic ciliate Isotricha prostoma and mixed rumen microorganisms.

A number of kinetic parameters of the lactate dehydrogenases of three rumen bacterial species (Peptostreptococcus productus, Propionibacterium acnes and Actinomyces viscosus), the rumen ciliate Isotricha prostoma and mixed rumen microorganisms (MRM) with respect to NADH, pyruvate, fructose-1,6-diphosphate (FDP) as well as the effects of several nucleotide phosphates were studied. Partially purified LDH of Peptostr. productus had the same kinetic parameters as in crude cell free extracts.

An analysis of the buffer system in the rumen of dairy cattle.

A method is presented for the analysis of buffer systems in the rumen using the first derivation of titration curves. Bicarbonate and volatile fatty acids (VFA) are the main components of the buffering system in the rumen fluid of dairy cattle under widely different feeding conditions. Phosphate from saliva is of little importance as a buffer, but neutralizes acids produced in the rumen.

Calculation of k and v from substrate concentration versus time plot.

A simple method for the calculation of kinetic parameters (K(m), V(max)) under conditions of changing substrate concentrations is presented. An application of the method to detect shifts in groups involved in the utilization of a substrate in a mixed microbial culture is given.

Relative significance of exogenous and de novo synthesized fatty acids in the formation of rumen microbial lipids in vitro.

Mixed rumen microorganisms (MRM) or suspensions of rumen Holotrich protozoa obtained from a sheep were incubated anaerobically with [1-(14)C]linoleic acid, [U-(14)C]glucose, or [1-(14)C]acetate. With MRM, the total amount of fatty acids present did not change after incubation. An increase in fatty acids esterified into sterolesters (SE) and polar lipids at the expense of free fatty acids was observed.

Methanogenic fermentation of benzoate in an enrichment culture.

Enrichment cultures inoculated with black mud fermented benzoate according to the stoichiometric equation: 4 C6H5CO2H+18 H2O → 15 CH4+13 CO2.Trans-2-hydroxycyclohexanecarboxylate, 2-oxo-cyclohexanecarboxylate, pimelate, caproate, butyrate, acetate, and molecular hydrogen were shown to be regular components of the culture fluid occurring in low concentrations. Inhibition of methanogenesis by chloroform, 4-chlorobutyrate, or 2-bromooctanoate resulted in a cessation of the benzoate breakdown after all intermediates had accumulated.

Vaginal embryogenesis, estrogens, and adenosis.

The recent outbreak of vaginal adenocarcinoma and the associated genital tract anomalies in women with histories of prenatal exposure to diethylstilbestrol (DES) has generated interest in vaginal embryogenesis and the influence of hormones on the developing genital tract. In this report the embryology of the vagina and the role of sex hormones in normal and abnormal sex duct development are presented and discussed in relation to the DES-induced anomalies. Although the teratogenic activity of DES in humans has been confirmed, the available evidence suggests that the clear cell carcinomas are initiated by endogenous estrogens and not the prenatally administered DES.

Isolated coccidioidomycosis of the uterus.

Coccidioidomycosis rarely involves the female genital tract. This report describes a case of coccidioidomycosis that was incidentally discovered involving the uterus of an asymptomatic 70 year old woman who had squamous carcinoma of the cervix. Reports of the few previously documented examples of coccidioidomycosis of the female genitalia are reviewed.

On the contribution of the acrylate pathway to the formation of propionate from lactate in the rumen of cattle.

The effect of chloral hydrate, an inhibitor of methanogenesis, on the participation of the acrylate pathway in the formation of propionate from lactate in rumen contents of cattle was studied in vitro. Addition of chloral hydrate resulted in only a small stimulation of the acrylate pathway, much lower than the stimulation of propionate production by chloral hydrate. This means that the flux of carbon through both the acrylate and the dicarboxylic acid pathway is increased during chloral hydrate feeding.

Lipid-phase transitions of the strictly anaerobic bacteria Veillonella parvula and Anaerovibrio lipolytica.

As a basis for physicochemical studies on the membranes of the strictly anaerobic bacteria Veillonella parvula, Anaerovibrio lipolytica, and Megasphaera elsdenii, the fatty acyl and alk-1-enyl moieties on the phosphoglycerides of these organism were characterized. Uncommon is the high proportion of a heptadecenoic acyl and alk-1-enyl moiety in these three lactate-fermenting bacteria. In contrast to V.

Some characteristics of Anaerovibrio lipolytica a rumen lipolytic organism.

Strains of Anaerovibrio lipolytica isolated from sheep- and cow-rumen contents on a linseed oil -- rumen fluid -- agar medium fermented ribose, glycerol and DL-lactate. Fermentation products from glycerol were propionate and succinate, while ribose, fructose and DL-lactate were fermented mainly to acetate, propionate and carbon dioxide. Propionate is formed in this organism by the dicarboxylic acid pathway similarly as in propionibacteria.