Dehydrogenation of a phosphonate substrate analogue by glycerol 3-phosphate dehydrogenase

S-(+)-3,4-Dihydroxybutylphosphonic acid, an isosteric analogue of sn-glycerol 3-phosphate, was synthesized stereospecifically and shown to be an effective substrate for rabbit muscle glycerol 3-phosphate dehydrogenase (sn-glycerol 3-phosphate-NAD(+) oxidoreductase, EC 1.1.1.8). Non-isosteric phosphonate analogues of sn-glycerol 3-phosphate showed neither substrate nor inhibitory activity with the enzyme.     

Microbiological Evaluation of Pacific Shrimp Processing

Microbiological evaluation of Pacific shrimp (Pandalus jordani) processing was made from samples obtained at five key processing points. The microbial count of raw shrimp ranged from 1.3 x 10(6) to 3.0 x 10(6). The initial microbial flora, in order of predominance, was Acinetobacter-Moraxella, Flavobacterium, Pseudomonas, gram-positive cocci, and Bacillus species. No yeasts were isolated. Differences in processing practices influenced both microbial count and the shrimp flora. The microbial load, however, always increased after peeling and sorting operations and decreased after cooking, washing, and brining steps. Significantly, the gram-positive cocci were recovered with increasing frequency after each processing step, reaching 76% of the total load in a final product. Most of them, however, were coagulase-negative.     

Alkaline-phosphatase and adenosine-triphosphatase histochemical reactions in the salivary glands of cat,dog and man,with particular reference to the myoepithelial cells

Summary Salivary myoepithelial cells were demonstrated by alkaline-phosphatase techniques in cat, but not in man or dog, and by an adenosine-triphosphatase technique in man, but not in cat or dog.Electron-microscopical cytochemistry showed that the reaction product from the respective techniques in cat and man was associated with the myoepithelial plasma membrane and that it was most constant and usually strongest at the plasma membrane adjacent to the acinar cells.In the dog, the reaction product from the adenosine-triphosphatase technique was found lining the canaliculi and lumina of the acini of the parotid gland, and of the non-mucous acini of the submandibular and sublingual glands. Alkaline-phosphatase reaction product was found lining the canaliculi and lumina in the sublingual gland.These remarkable species differences indicate that neither technique can be regarded as a universal marker of salivary myoepithelial cells. Inconsistencies in activity were found within the myoepithelium of individual glands and suggest that even the appropriate technique may not be relied upon to demonstrate all the myoepithelial cells present in a tissue section.

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Zusammenfassung Myoepithelzellen der Speicheldrüsen lassen sich bei der Katze — nicht jedoch bei Mensch und Hund — mittels der alkalischen Phosphatase-Reaktion darstellen. Der Nachweis für Adenosintriphosphatase fällt in diesen Zellen beim Menschen, nicht bei Katze und Hund, positiv aus.Elektronenmikroskopisch-cytochemisch zeigt sich, daß das Reaktionsprodukt der jeweiligen Methode bei der Katze und beim Menschen an den Plasmamembranen der Myoepithelzellen auftritt und zwar am regelmäßigsten und meistens am stärksten in der Nachbarschaft der Azinuszellen.Beim Hund fällt in der Ohrspeicheldrüse sowie den nicht-mukösen Acini der Glandulae submandibularis und sublingualis das Reaktionsprodukt der Adenosintriphosphatase-Reaktion an der Begrenzung der Azinuskanälchen und der Lumenoberfläche aus. Alkalische Phosphatase ist in der Glandula sublingualis in den Wänden der Kanälchen und an den Lumina lokalisiert.Diese bemerkenswerten Unterschiede zwischen den verschiedenen Tierarten zeigen, daß keine der verwendeten Methoden zur Universalmarkierung von Myoepithelzellen der Speicheldrüsen geeignet ist. Außerdem ist die Aktivität des Myoepithels bei den einzelnen Drüsen uneinheitlich. Dies legt die Vermutung nahe, daß man sich selbst bei Anwendung der richtigen Methode nicht darauf verlassen kann, alle in einem Gewebsschnitt vorhandenen Myoepithelzellen zu erfassen.

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This work has been supported by a Medical Research Council Grant.     

Solitary Song and its inhibition in some Estrildidae

Summary In the species studied song appears to have two functions; an epigamic function = Display Song, and a contact function = Solitary Song. Solitary Song appears to be common to all the species studied. Its utterance indicates that the bird is unpaired or separated from another individual with which it has formed a bond. InUraeginthus bengalus, U. angolensis, andAmandava amandava Solitary Song is also uttered by the hen in similar circumstances. InLonchura punctulata, A. amandava, andEuodice malabarica song is usually but not completely inhibited by the presence of a mate, in whose absence Solitary Song will be uttered even when other individuals of the same species are present. In the species studied of the generaEstrilda, Lagonosticta, andUraeginthus Solitary Song is inhibited by the continued close proximity of another bird even though this may be of the same sex or of a different species and may elicit aggressive or fleeing reactions; but conditions of close association with a bird other than a suitable mate would presumably only occur under captive conditions. There appears to be a distance factor controlling such inhibition. There is evidence of the inhibition of song due to the presence of a mate in other passerine species.