Lysine-ketoglutarate reductase activity in developing maize endosperm

Lysine-ketoglutarate reductase activity was detected and characterized in the developing endosperm of maize (Zea mays L.). The enzyme showed specificity for its substrates: lysine, α-ketoglutarate, and NADPH. Formation of the reaction product saccharopine was demonstrated. The pH optimum of the enzyme was close to 7, and the K_m for lysine and α-ketoglutarate were 5.2 and 1.8 millimolar, respectively.     

Proton efflux associated with melibiose permease activity in Salmonella typhimurium.

Transport of thiomethyl-β-D-galactoside (TMG) via the melibiose permease system (TMG permease II) in $\text{Salmonella typhimurium}$ is known to be a sodium-dependent co-transport system. We have shown that this co-transport of sodium and TMG is associated with extrusion of protons from the cells. The rate and extent of proton extrusion during TMG uptake were measured in wild-type cells and mutants containing internal and extended deletions in the $\text{pts}$ locus. No differences between these various strains were noted.     

Photosensitization in cattle grazing on pastures of Brahciaria decumbens Stapf infested with Pithomyces chartarum (Berk. & Curt.) M.B. Ellis

Aspects of photosensitization in bovines grazing on pastures of Brachiaria decumbens Stapf infested with Pithomyces chartarum (Berk. & Curt.) M.B. Ellis infested all pastures 45(2):117-136, 1978. This paper reports experimental studies on photosensitization in bovines grazing on different pastures of Brachiaria decumbens Stapf in the "Cerrados" region (Planaltina, DF). Climatic conditions, zinc content and occurence of fungi on pastures were investigated. Pithomyces chartarum (Berk. & Curt.) M.B. Ellis infested all pastures examined. Photosensitization was observed in one animal maintained on a pasture of B. decumbens formed with seeds from Australia. Clinical and necropsy data were similar to those related in literature for sporidesmin-intoxicated animals. An isolate of P. chartarum and samples of bovine bile were assayed for sporidesmin presence.     

Trisomy iop.

A stillborn male fetus having a trisomy of the short arm of chromosome No 10 is described. The father is a carrier of the reciprocal translocation 46XY,t(10;21) (10pter leads to 10p11::21p11 leads to 21qter). The clinical picture included growth retardation, bilateral cleft lip and palate, micrognathia, short neck, microphalus and bilateral clubbed feet. The long bones were markedly thinned with spontaneous fractures. Autopsy findings included pulmonary hypoplasia and renal dysplasia. Previous reports of trisomy 10 and trisomy of the short arm of chromosome 10 are discussed.     

Bacterial mesosomes: Real structures of artifacts?

The ultrastructural study of membrane organization in gram-positive bacteria related to the OsO₄ fixation conditions revealed that large, complex mesosomes are observed only when the bacteria are subjected to an initial fixation with 0.1% OsO₄ in the culture broth, as in the prefixation step of the Ryter-Kellenberger procedure. Evidence was obtained suggesting that the large mesosomes are produced by this prefixation. The kinetic study of the membrane morphological alterations occurring during the prefixation of Bacillus cereus with 0.1% OsO₄ in the culture broth showed that the amount of mesosome material increases linearly from zero to a maximum observed at 1.7 min of prefixation and that at about this time a maximum is reached for the number of mesosomes per unity of cell area and for the average individual mesosome area. The large mesosomes observed in gram-positives fixed by the complete Ryter-Kellenberger procedure would be the result of the membrane-damaging action of 0.1% OsO₄. Such damaging action was deduced from the observation that 0.1% OsO₄ quickly lyses protoplasts and induces a quick and extensive leakage of intracellular K⁺ from B. cereus and Streptococcus faeculis. In support of that interpretation is the observation that in bacteria subjected to several membrane-damaging treatments, mesosome-like structures are seen after three different fixation procedures. In bacteria initially fixed with 1% OsO₄, 4% OsO₄ or 2.5% glutaraldehyde, no large, complex mesosomes are observed, small and simple invaginations of the cytoplasmic membrane being present. The size of these minute mesosomes is inversely proportional that causes of fixation. Uranyl acetate was found among the studied fixatives the one to the rate the least damage to bacterial membranes. This fixative satisfactorily preserves protoplasts. In bacteria initially fixed with uranyl acetate no mesosomes were found. The results of the present work throw serious doubts on the existence of mesosomes, both large and small, as real structures of bacterial cells. It is proposed that a continuous cytoplasmic membrane without infoldings (mesosomes) would be the real pattern of membrane organization in gram-positives.     

Liver transplantation in a patient with cholangiocarcinoma and ulcerative colitis.

A 39 year-old patient with cholangiocarcinoma and pre-existing ulcerative colitis was successfully treated by orthotopic liver transplantation. He was given low doses of prednisone and azathioprine and survived for more than 9 months, dying with tumour metastases, thrombosis of the inferior vena cava and an intra-abdominal abscess. At autopsy the homograft showed little evidence of rejection. Preoperatively the patient had septicemia. Removal of his liver was difficult. The discrepancy between donor and recipient in size of blood vessels and the presence of two hepatic arteries in the donor caused problems during the vascular anastomoses. During the operation cardiac arrest occurred. Postoperatively there were several medical and surgical problems, including intraperitoneal and gastrointestinal hemorrhage, paralysis of the right dome of the diaphragm, sinus bradycardia, massive diuresis, peroneal nerve palsy, and one major and three minor episodes of rejection, which were reversed by giving pulse doses of methylprednisolone intravenously.     

The fine structure of Micrococcus radiophilus and Micrococcus radioproteolyticus

The radiation resistant bacteria Micrococcus radiophilus and M. radioproteolyticus were studied by thin sectioning and freeze-etching techniques and the two species were found to be similar in the fine structure. The only significant difference was in the appearance of the surfaces of the cell walls in freeze-etched preparations.Since the two species, together with M. radiodurans, possess a unique cell wall structure and a cell wall peptidoglycan, which is different from that of other micrococci and Gram-positive cocci, it is recommended that they be reclassified into a new genus.     

Norditerpene dilactones from Podocarpus saligna

Rimuene and nubigenol have been identified in Podocarpus saligna for the first time, and the structures of three new norditerpene dilactones, salignones K, L and M, isolated from this species have been elucidated.     

Diterpenoids from Micrandropsis scleroxylon

The structure of micrandrol-C from Micrandropsis scleroxylon (Euphorbiaceae) is revised to 2,6-dihydroxy-7-methyl-1-methylthiophenanthrene. This and other micrandrols are probably diterpenes in view of their co-occurrence with micrandrol-D, the hemiketal of 1,2,3,4,9,10-hexahydro-6-hydroxy-4a-hydroxymethyl-1,1,7-trimethy-2-oxophenanthrene.