Pseudonajatoxin b: unusual amino acid sequence of a lethal neurotoxin from the venom of the Australian common brown snake, Pseudonaja textilis

The complete amino acid sequence of pseudonajatoxin b, a basic neurotoxin from the venom of the Australian common brown snake, Pseudonaja textilis, was determined by automated Edman analysis of the reduced carboxymethylated polypeptide and of peptides derived by digestion of it with Staphylococcus aureus V8 proteinase. Pseudonajatoxin b consists of a single polypeptide chain of 71 amino acids with Mr 7762. The amino acid sequence showed considerable homology with postsynaptic long neurotoxins, but there were striking differences. Pseudonajatoxin b displayed relatively high lethality, LD50 15 micrograms/kg in mice.     

Does anaemia increase the risks to the fetus caused by smoking in pregnancy?

A significantly greater rise in carboxyhaemoglobin concentration in response to smoking a single cigarette was shown in pregnant (3-9% increase) as opposed to non-pregnant (2-1% increase) women. This was more pronounced when anaemia was present (5-0% increase) and appeared to be inversely related to the haemoglobin concentration. We suggest that the risks to the fetus may be particularly increased when anaemia complicates pregnancy in women who smoke cigarettes.     

Health and chemical burdens of fish species from polluted and hyper-eutrophic freshwater ecosystems in South Africa

Three aquatic ecosystems in South Africa, the Hartbeespoort, Klipvoor and Bospoort Dams, are classified as hyper-eutrophic, because of high nutrient loads and chemical pollution. Water and two fish species, Clarias gariepinus and Cyprinus carpio, were collected from these dams to assess the impact of eutrophication and chemical pollutants on their health status. Water and muscle samples were analysed for organic and inorganic chemicals. Condition factor was determined and a necropsy performed to note any macroscopic abnormalities. A histology-based fish health assessment was done on the liver, kidney, gills and gonads. A number of fish from the three dams exhibited livers with fatty change and focal discoloration, skin lesions and parasites within the visceral cavity. The prevalence and severity of histopathology in the liver resulted in higher liver index values than the index values for kidneys and gills. Aluminium, silicon and chromium were detected in the water and muscle tissue. The DDT metabolite p,p’-DDE was present in both species, as well as in fish from the reference site, Marico-Bosveld Dam. Only C. gariepinus from Hartbeespoort Dam had p,p’-DDD levels higher than 5 µg g^?1 per edible portion. Water from hyper-eutrophic dams adversely affects the health of freshwater fish.     

Differential synthesis of bacteria-induced proteins of Manduca sexta larvae and pupae

The range of inducible antibacterial and other associated haemolymph proteins in Manduca sexta larvae and pupae was examined by high resolution two-dimensional (2D) isoelectric focusing-polyacrylamide gel electrophoresis. Twenty-two major inducible proteins were consistently resolved on gels of haemolymph from bacteria-injected larvae. Haemolymph from bacteria-injected pupae showed a different pattern of induced proteins. The proteins of the two stages include those which (i) are induced in both stages, (ii) those which are exclusively induced in either larvae or pupae, (iii) those which are inducible in larvae, but consititutively present in pupae, and, (iv) those which are induced in larvae, and which are present at intermediate levels but may be induced to higher levels in pupae.The antibacterial activity of the haemolymph from larvae and pupae was compared on acidpolyacrylamide gels, and the apparent M_r and pI of the inducible proteins determined. Certain of the inducible proteins appear to resemble the cecropin and attacin proteins of Hylophora cecropia.     

Non-secretory solitary plasmacytoma of the spleen

A case of primary nonsecretory plasmacytoma of the spleen is reported. On laparotomy and splenectomy a 920 g spleen was removed, measuring 16×14×6 cm. The cut surface of the entire spleen showed that the tumour occupied most of the splenic tissue. A bone marrow aspirate and trephine, skeletal survey showed no signs of myeloma. Biopsy of the liver and regional lymph nodes was normal. Immunocytochemistry of the splenic tumour showed positivity for pan-B and plasma cell markers. After splenectomy the patient was treated with chemotherapy according to protocol VBCMP (M2).