Bicyclo[3,2,1]octanoid,neolignans from Aniba simulans

Six bicyclo[3,2,1]octanoid neolignans, isolated from the benzene extract of Aniba simulans Allen (Lauraceae) trunk wood, are shown to derive from two basic structures: 1-allyl-8-hydroxy-6-(3′-methoxy-4′,5′-methylenedioxyphenyl)-7-methyl-3-oxobicyclo[3,2,1]octane, substituted by 4-hydroxy, 4-hydroxy-5-methoxy, 4-methoxy or 4,5-dimethoxy groups; and 1-allyl-8-hydroxy-6-(3′-methoxy-4′,5′-methylenedioxyphenyl)-7-methyl-4-oxobicyclo[3,2,1]oct-2-ene, substituted by 3-hydroxy or 3-hydroxy-5-methoxy groups. The structural proposals are based on spectral data, interconversions synthesis of a derivative from the known (2R,3S,3aS)-3a-allyl-5-methoxy-2-(3′-methoxy,4′,5′-methylenedioxyphenyl)-3-methyl-2,3,3a,6-tetrahydro-6-oxobenzofuran.     

Nitrogen fixation throughout growth,and varietal differences in nitrogen fixation by the rhizosphere of rice planted in pots

Summary The nitrogen-fixing activity in the rhizospheres of various rices was measured by the acetylene-reduction method throughout plant growth in green-house pots. The activity began to increase 4 weeks after transplanting, increased until heading stage, then decreased. The concentrations of exchangeable ammonium and sugars in the soil were not related to the variation of nitrogen-fixing activity during rice growth.The nitrogen-fixing activities in the rhizospheres of 41 rice varieties in pots were measured to discover varietal differences. Levels of nitrogen fixation were highly correlated with the rices' dry root weight at heading stage.     

CROSS-SECTIONAL ECHOCARDIOGRAPHIC FINDINGS IN VEGETATIVE AORTIC VALVE ENDOCARDITIS

M-mode echocardiograms of two patients with bacterial endocarditis of approximately 4 months' duration showed dense echoes in the area of the aortic valve. In one patient, who had no prior abnormal cardiac findings, the echoes were clearly suggestive of valvular vegetations. The second patient, however, was known to have had aortic valve disease and a systolic murmur for more than a decade; therefore, dense echoes arising from the aortic valve also could have resulted from valvular calcification. In both patients, cross-sectional echocardiography provided important information. In the first patient, retrograde cardiac catheterization was prevented by large and highly mobile masses attached to the aortic cusps that prolapsed into the left ventricular outflow tract during diastole. Aortic valve replacement without further hemodynamic evaluation was recommended. In the second patient, whose blood cultures remained negative after the acute phase of his illness had been treated, cross-sectional echocardiography showed large vegetations on the aortic valve. Intraoperative findings confirmed the echocardiographic interpretation in each case.     

Isolation and identification of β 1 → 2-d-glucans in extracellular polysaccharides of Rhizobium meliloti strain L5-30

Abstract Exopolysaccharides have been found as bound to R. meliloti cells (strain L5-30) or free in the culture medium; they consist of acidic and neutral polysaccharides. Bound and soluble neutral polysaccharides were identified as β 1 → 2 linked glucans with an average M _r value of 4000 to 6000.     

Spatial and temporal gene expression patterns occur during corm development.

We investigated gene expression patterns that occur during taro corm development. Two-dimensional gel electrophoresis identified several different prevalent proteins that accumulate during corm development. Microsequencing studies indicated that some of these proteins are related to taste-modifying proteins, such as curculin and miraculin, and proteins found in other storage organs, such as sporamin and the Kunitz trypsin inhibitor. A curculin-encoding cDNA clone, designated as TC1, was identified that corresponds to a highly prevalent 1-kb corm mRNA. The TC1 mRNA accumulates during corm development, is more prevalent in corm apical than basal regions, and is either absent, or present at low concentrations, in other vegetative organs such as the leaf and root. In situ hybridization experiments showed that the TC1 mRNA is highly concentrated in corm storage parenchyma cells and is absent, or present in reduced concentrations, in other corm cells and tissues. Our results show that corm development is associated with the differentiation of specialized cells and tissues, and that these differentiation events are coupled with the temporal and spatial expression of corm-specific genes.     

Prothymosin alpha is phosphorylated by casein kinase-2.

Prothymosin alpha (ProT alpha) is a 12.5 kDa acidic polypeptide that is considered to have a nuclear function related to cell proliferation. Inspection of its amino acid sequence revealed the presence of sequences that may serve as targets for phosphorylation by casein kinase-2 (CK-2). ProT alpha isolated from calf thymocytes was phosphorylated in vitro by CK-2. The phosphorylation sites are Ser and Thr residues located among the first 14 amino acid residues in the ProT alpha sequence. Another site that is theoretically suitable for phosphorylation by CK-2, at the C-terminus of the polypeptide, is not, in fact, phosphorylated. Thymosin alpha 1 (T alpha 1), a peptide whose sequence corresponds to the first 28 amino acids of ProT alpha, is also phosphorylated by CK-2 at the same phosphorylation sites as ProT alpha. In cultured splenic lymphocytes ProT alpha was phosphorylated at Thr residues located at positions 7, 12 and/or 13. Based on these observations we conclude that CK-2, or another cellular kinase with similar sequence specificity, is responsible for phosphorylation of ProT alpha in vivo.     

Effect of corticosteroids on the congenital transmission of experimental toxoplasmosis]

Female white mice with chronic toxoplasmosis were treated with cortisone acetate (3mg for each 25 g of body weight) 12, 8, 4 and 0 days before mating. Cortisone induces congenital transmission of T. gondii.     

Chemotactic Behavior of Azotobacter vinelandii

Chemotaxis was exhibited by Azotobacter vinelandii motile cells. Exposure of cells to sudden increases in attractant concentration suppressed the frequency of tumbling and resulted in smooth swimming. Cells responded chemotactically to a chemical gradient produced during metabolism. Motility occurred over a temperature range of 25 to 37°C with an optimum pH range of between pH 7.0 and 8.0. The average speed of motile cells was determined to be 74 μm/s or 37 body lengths per s. The speed of cells appeared to increase as a function of attractant concentration. Chemotactic systems for fructose, glucose, xylitol, and mannitol were inducible. A. vinelandii exhibited chemotaxis for a number of compounds, including hexoses, hexitols, pentitols, pentoses, disaccharides, and amino sugars. We conclude from these studies that A. vinelandii exhibits a temporal chemotactic sensing system.