Effects of sodium chloride and sodium bicarbonate in the diet on the performance of calves

Sixty male Friesian calves were weaned from milk at 5 weeks of age. From 3 to 11 weeks of age, the calves were offered a diet of barley, meat meal, urea and 15% oat straw, supplemented with sodium chloride (NaCl) or sodium bicarbonate (NaHCO₃). The sodium (Na) contents of the diets supplemented with NaCl were 0.3, 1.1, 1.9 and 2.8%. The sodium contents of the diets supplemented with NaHCO₃ were 1.1 and 1.9%.The performance of the calves fed on the diets containing 0.3, 1.1 and 1.9% Na from NaCl was similar, but the organic matter intake and weight gains of the calves fed on the diet containing 2.8% Na were significantly lower between 5 and 11 weeks of age. The feed intake of the calves fed on the diets containing 1.1 and 1.9% Na from NaHCO₃ was 8 and 15% greater than the feed intake of the calves fed on the diet containing 0.3% Na. However, there was no significant difference in the intake of organic matter, the efficiency of feed conversion ratios or the weight gains of the calves.The sodium treatments resulted in no significant differences in the concentration of volatile fatty acids in the rumen. The addition of NaHCO₃ to the diets altered in acid—base balance in jugular blood.     

Morphological pathway of flagellar assembly in Salmonella typhimurium.

The process of flagellar assembly was investigated in Salmonella typhimurium. Seven types of flagellar precursors produced by various flagellar mutants were purified by CsCl density gradient protocol. They were characterized morphologically by electron microscopy, and biochemically by two-dimensional gel electrophoresis. The MS ring is formed in the absence of any other flagellar components, including the switch complex and the putative export apparatus. Four proteins previously identified as rod components, FlgB, FlgC, FlgF, FlgG, and another protein, FliE, assemble co-operatively into a stable structure. The hook is formed in two distinct steps; formation of its proximal part and elongation. Proximal part formation occurs, but elongation does not occur, in the absence of the LP ring. FlgD is necessary for hook formation, but not for LP-ring formation. A revised pathway of flagellar assembly is proposed based on these and other results.     

Lipid composition of the epidermal gel secretion from the Arabian Gulf catfish (Arius thalassinus Ruppell)

Lipids associated with a threat induced epidermal gel secretion from the catfish, Arius thalassinus, have been analyzed. Phospholipids, neutral lipids and glycolipids are all present and each of these subclasses has been analyzed by thin layer and gas chromatography with a general similarity with membrane lipids being noted. The epidermal gel lipids differed from total liver lipids of the catfish. Fatty acid analysis showed the gel lipid to be rich in the unsaturated fatty acids: oleate (omega 7, C18:1), arachidonate (omega 6, C20:4), and docosahexaenoate (omega 3, C22:6). Some prostaglandins were quantitated in lipid extracts from the epidermal gel.     

THE INSECTICIDES—Their Hazard in Industry and in the Home Part II—Clinical Aspect

Within the past decade the chemist has evolved a new group of insecticides having a greater range of toxicity to insects—and to man. Since their use is ubiquitous, it is imperative that information be widely disseminated regarding proper cautionary measures as well as the early signs and symptoms of toxicity.     

The life stages and population dynamics of an arid zone scorpion Urodacus yaschenkoi (Birula 1903)

The arid zone scorpion Urodacus yaschenkoi (Birula 1903) is shown to have six instars. Instars can be recognized by measuring the claws and the carapace plus first five tail segments. A population study, carried out at Coombah, NSW, showed that the life history consisted of mating in September–October, 18 month gestation, birth in February-March, moult to second instar March-April and annual moults to sixth instar in December–February. The minimum generation time was 6 y, and the population appeared to be stable. The calendar of catches method was used to determine the population size (about 400 animals in 2240 m²) but required some extra assumptions to cope with loss of marks from individuals when they moulted.