Changes in diet,prey size and feeding habit in Bagrus bayad,and possible interactions with B. docmac in a Nile canal

Synopsis Bagrids in Bahr Shebeen Nilotic canal depend mainly on fish, insects and shrimp as well as fish embryos for food and their stomachs included runoff materials (e.g. plant foliage, glass, black crystals, coloured gravel). B. bayad maximised its efficiency of catching prey catfish by face to face attack to avoid damage by the prey's pectoral and dorsal spines. In the size classes of 10 to 30 cm standard length, B. bayad and B. docmac show diet overlap and interact with each other especially with respect to tilapias as prey. After this length, B. docmac, aided by its relatively larger mouth, shifted to larger size of tilapias to coexist with B. bayad.     

Macrophylloside, a flavone glucoside from Primula macrophylla

A new flavone glucoside macrophylloside has been isolated from the whole plant of Primula macrophylla and its structure was determined by spectroscopic methods as 2′-hydroxy-7-O-β- -glucopyranosyloxyflavone. Sitosterol glucoside was also isolated for the first time from this plant.     

Host-vector systems for the thermotolerant methanol-utilizing bacteriaMethylophilus spp. KISRI-Strains

Fourteen recombinant plasmids were constructed by inserting fragments of pSAS, a naturally occurring plasmid ofMethylophilus spp. KISRI-5, into the multiple cloning sites of pUC19. Six recombinants and three knownEscherichia coli plasmids were used to transform three thermotolerant methylotrophic KISRI strains by use of an optimized protocol of electroporation. Analysis of transformants for plasmid DNA showed that all plasmids were stable in the methylotrophic hosts. These studies offer opportunities to developMethylophilus spp. as host-vector systems.     

Role of verocytotoxigenic Escherichia coli in cattle and buffalo calf diarrhoea

Abstract 273 Strains of Escherichia coli isolated from diarrhoeic and healthy control cattle and buffalo calves in Sri Lanka, were tested for Verocytotoxin (VT) and for heat-stable (ST) and heat-labile (LT) enterotoxins. VT and ST toxigenic E. coli were significantly associated with diarrhoea, accounting for 28% and 18% of diarrhoeic episodes, respectively. LT toxigenic E. coli were not significantly associated with diarrhoea.     

Lineage-specific expression of c-fos and c-fms in human hematopoietic cells: Discrepancies with the in vitro differentiation of leukemia cells

In vitro differentiation studies using the bipotential human leukemia cell line, HL60, have indicated that high levels of expression of two proto-oncogenes, c-fos and c-fms, are restricted to the myelomonocytic lineage. No such expression has been detected in induced granulocytic cells. In striking contrast to these observations, we found that c-fos mRNA levels are very high in purified human granulocytes, but barely detectable in blood monocytes and tissue macrophages. Human granulocytes contain, however, relatively low levels of c-fos protein, indicating that c-fos mRNA is inefficiently translated or that the protein is rapidly degraded in these cells. In closer agreement with the in vitro results, the level of the expression of c-fms is high in purified blood monocytes and undetectable in granulocytes. We found, however, that the evolution of monocytes into tissue macrophages is accompanied by a significant decrease in c-fms expression, suggesting that the function of c-fms is restricted to specific stages of monocytic differentiation. Our observations also show that results obtained using in vitro differentiation systems have to be regarded with caution, since they may not reflect the in vivo situation.     

Serotypes of verocytotoxigenic Escherichia coli isolated from cattle and buffalo calf diarrhoea

Abstract Parasporal crystals of the recently isolated Bacillus thuringiensis var. tenebrionis are toxic for coleopteran larvae. Unlike those of other strains they are soluble either in aqueous solutions of NaBr at neutral pH or in water after titration to pH values above pH 10.0. The dissolved crystal protein readily forms crystals after removal of the salt or neutralization. The crystal protein was not found to differ much in the amino acid composition from other crystal proteins. The parasporal crystals are composed of subunits of M _r 68 000 which are not linked by disulfide bridges.     

Rearing, reproductive behaviour and gamma sterilization of fruit fly, Dacus zonatus (Diptera: Tephritidae)

Investigations were made on rearing, reproductive behaviour and gamma sterilization of one-day old male adults of Dacus zonatus. The larvae were successfully reared on an artificial diet based on wheat shorts. Adult emergence ranged from 89–99% with a sex ratio of about 1:1. Mating occurred at dusk and its duration ranged from 8–13 hours. Males mated a second time with the same female but preferred mating if the already mated female was replaced with a sexually mature virgin female. The optimum dosage for inducing sterility amongst one-day old male adults was 12 kR.

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Zusammenfassung Zucht und Fortpflanzungsverhalten von Dacus zonatus (Saunders) wurde untersucht. Die Larven wurden vier Generationen lang an einer Diät aus Weizenkleie, Bierhefe, granuliertem Zucker, Agar, Nipagin, Salzsäure und Wasser gehalten. Die Arbeit gibt Daten über Verpuppungsprozentsatz (69,3%), Puppengewicht, Dauer der Ei + Larvenperiode, Schlüpfen der Adulten, Präovipositionszeit, Fruchtbarkeit, Fertilität und Lebensdauer der Adulten. Die Schlüpfrate der Adulten betrug 89–99%, das Geschlechtsverhältnis lag etwa bei 1:1. Die Kopulation findet während der Abenddämmerung statt, sie dauert 8–13 Stunden. Maximum der Kopulationen zwischen dem 10. und 15. Tag nach dem Schlüpfen. Männchen paarten sich ein zweites Mal mit dem gleichen Weibchen, bevorzugten jedoch geschlechtsreife jung-fräuliche Weibchen. Die Eiablage begann am 2.–7. Tag nach der Paarung, die Eizahl betrug bei gepaarten Weibchen 91–564.Die optimale Dosis zur Erzeugung von 99,3% Sterilität bei Bestrahlung von einem Tag alten Männchen war 12 kR. Die Lebensdauer der Bestrahlten war vermindert.