Application of the API YeastIdent system in determining the enzymatic profiles ofNocardia asteroides isolates

Glucose represses production of ammonium in many clinical isolates ofNocardia asteroides growing on bromcresolpurple casein glucose agar. Strains exhibiting this property are designated as group A, while group B represents isolates showing a high degree of proteolytic activity and a resulting rapid increase in pH. Twenty isolates ofN. asteroides were characterized as group A or B. Enzymatic profiles obtained using the API YeastIdent system showed significant enzymatic variation between 12 group B and 8 group A isolates. Proteolytic enzymes which most varied in activity between groups were glycine aminopeptidase, histidine aminopeptidase and leucyl glycine aminopeptidase. As some of theN. asteroides isolates were isolated from asymptomatic patients, it is of interest to consider the possibility of one group being of low virulence while the other is more strongly associated with infection.     

Detection of mycotoxins in foodstuffs by use of chick embryos

A method of extracting fungal cultures with aqueous methanol and hexane is described. The extract from 100 grams of foodstuff, or pure fungal cultures on cereals (maize, wheat and rye), was inoculated into groups of twenty fertile hens eggs, both into the air sac and into the yolk, which were then incubated through to hatch at twenty-two days. The results show good sensitivity to aflatoxin and sporidesmin. The fungal cultures are recorded as toxic (below 50% hatch) non toxic (above 68% hatch) and doubtful. Five isolates ofAspergillus repens isolated from one batch of mouldy hay gave a high (43%) incidence of deformed embryos. This method is suggested as a general biological test for toxicity in foodstuffs.     

A comparative account of the life cycles of Lumbricillus lineatus Mull. and Enchytraeus albidus Henle in relation to temperature

Compared with Lumbricillus lineatus the cocoons of Enchytraeus albidus are smaller and contain fewer eggs whilst the egg production per worm is higher and sterility among the eggs lower. The fecundity of E. albidus is greater over a temperature range 1–25 and is not so adversely affected at the higher or lower temperatures as L. lineatus. Incubation in E. albidus is longer than in L. lineatus but the time required for maturation is much shorter, the periods depending upon the temperature. There is a similar relation to temperature as in the case of fecundity, with E. albidus again more tolerant to heat and cold. There is no relation between size and temperature but unlike L. lineatus , growth occurs after maturation in E. albidus and its cocoons (after the first) and their egg content are larger. There is no apparent relation between the setae length and temperature. The temperature relations favour a more rapid increase of E. albidus in the bacteria beds than of L. lineatus but they are well suited to the distribution of the species under natural conditions, E. albidus favouring a terrestrial habitat whereas L. lineatus exists in moister places. Further, they show specific physiological differences distinguishing the two species of worms.     

On the systematics and distribution of the molluscan genus Siphonaria in South Africa

Summary A revision of the systematics of the genus Siphonaria found around the South African coast from Port Nolloth on the West coast to Inhaca Island on the East coast is given. Of the twelve species described by Hubendick (1946) as occuring on the South African coast only five are valid. The remainder are reduced to synonyms. Two new species and one new variety are described.The horizontall distribution along the coastline of the valid species is described. Three species are recorded from the cold waters of the West coast while six species are recorded from the East coast. S. deflexa and S. oculus have a western distribution limit in False Bay. While S. dayi sp. nov. is only known from Inhaca Island. S. anneae and S. carbo occur in the subtropical waters near Durban. S. capensis and S. aspera are ubiquitous. S. compressa sp. nov. occurs only on the West coast in the sheltered waters of Langebaan lagoon, Saldanha Bay.Department of Zoology, University of Cape Town     

A comparative study on the effect of cotton dust and 2, 4-D on three pathogenic fungi

Summary The present work aims at the elucidation of the effect of either cotton dust and its components or 2,4-D on the relative vigours of the three pathogenic fungi namely,Fusarium solani, Sclerotium bataticola andBotrytis fabae. Botrytis mycelial growth was found to be comparatively more sensitive to cotton dust thanFusarium andSclerotium. The elucidation of the effect of individual cotton dust components has shown that Gammexane is the most effective inhibitory component while sulphur and DDT caused slight inhibition. This inhibitory effect of Gammexane is more pronounced when mixed with DDT than with sulphur. 500 p.p.m. 2,4-D concentration inhibitedBotrytis growth more thanFusarium orSclerotium, 1 % 2,4-D concentration was proved to be fungicidal. 2,4-D suppressed the germinative potentialities ofFusarium andBotrytis conidia.

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Zusammenfassung Die jetzige Arbeit trachtet nach der Aufklärung der Wirkung des Baumwollstaubes und seiner Bestandteile, und des 2,4-D auf die relative Widerstandsfähigkeit von drei pathogen Pilzen, nämlich,Fusarium solani, Sclerotium bataticola undBotrytis fabae. Mycelium-Wachstum vonBotrytis war vergleichsweise empfindlicher gegen Baumwollstaub als vonFusarium undSclerotium. Die Aufklärung der Wirkung der individuellen Komponenten des Baumwollstaubes zeigte, daß Gammexane der wirksamste, verzögernde Bestandteil ist, während Sulfur und DDT nur eine geringfügige Verzögerung verursachten. Die verzögernde Wirkung von Gammexane ist ausgesprochener, wenn es mit DDT als mit Sulfur gemischt ist. Die Konzentration von fünfhundert Teilen in 1 Million von 2,4-D unterdrückt das Wachstum vonBotrytis mehr als das vonFusarium oderSclerotium, die Konzentration von 1 % des 2,4-D war pilztötend. 2,4-D unterdrückte die Keimungsmöglichkeit vonFusarium undBotrytis Conidia.