Interrelationship of kernel water activity,soil temperature,maturity, and phytoalexin production in preharvest aflatoxin contamination of drought-stressed peanuts

Samples of Florunner peanuts were collected throughout a period of late-season drought stress with mean geocarposphere temperatures of 29 and 25 °C, and determinations of maturity, kernel water activity (a_w), percent moisture, capacity for phytoalexin production, and aflatoxin contamination were made. Results showed an association between the loss of the capacity of kernels to produce phytoalexins and the appearance of aflatoxin contamination. Kernel a_w appeared to be the most important factor controlling the capacity of kernels to produce phytoalexins. Mature peanuts possessed additional resistance to contamination that could not be attributed solely to phytoalexin production. Kernel moisture loss was accelerated in the 29 °C treatment compared to the 25 °C treatment, and data indicated that the higher soil temperature also favored growth and aflatoxin production by Aspergillus flavus in peanuts susceptible to contamination.Mention of a trademark or proprietary product does not constitute a guarantee or warranty of the product by the U.S. Department of Agriculture and does not imply its approval to the exclusion of other products that may also be suitable.     

Construction of a shuttle vector for Zymomonas mobilis

Summary An Escherichia coli-Zymomonas mobilis shuttle vector was constructed from a 15.5 kb native plasmid of ZM6 00 and the E. coli plasmid, pBR329. Integrative transfer of this shuttle vector from E. coli to Z. mobilis was achieved with the aid of the mobilizing plasmid, pRK2013. The shuttle vector was stable in Z. mobilis for at least 300 generations without antibiotic selection.Offprint requests to: S. F. Delaney     

Higher order structure is present in the yeast nucleus: autoantibody probes demonstrate that the nucleolus lies opposite the spindle pole body

A panel of sera from 892 autoimmune patients was screened by indirect immunofluorescence on mammalian cells. Seventy-three sera were identified that recognize the nucleolus. Three of these sera appear to stain the nucleolus in yeast, suggesting that they recognize highly conserved antigens. These three sera also immunoprecipitate mammalian U3 snRNA-containing particles, which reside in the nucleolus and have been implicated in rRNA processing. Double immunofluorescence experiments with anti-nucleolus and anti-tubulin antibodies revealed a novel form of non-random nuclear organization in yeast. The spindle pole body and the nucleolus — both of which are associated with the nuclear envelope — preferentially localize at opposite ends of the nucleus. Organization of these and other components into specific regions of the nucleus may be important for optimizing their proper function.     

Physiological Characterization of Dicarboxylate-Induced Pleomorphic Forms of Bradyrhizobium japonicum

When Bradyrhizobium japonicum I-110 was transferred into medium containing 40 mM succinate or 40 mM fumarate, over 90% of the bacteria acquired a swollen, pleomorphic form similar to that of bacteroids. The induction of pleomorphism was dependent on the carbon substrate and concentration but was independent of the hydrogen ion and sodium ion concentration. Cell extracts of rod-shaped and pleomorphic cells contained enzymes required for sugar catabolism and gluconeogenesis. Variations in these enzyme profiles were correlated with the carbon source used and not with the conversion to the bacteroid-like morphology. Rod-shaped cells cultured on glucose or 10 mM succinate transported glucose and succinate; however, the pleomorphic cells behaved similarly to symbiotic bacteroids in that they lacked the ability to transport glucose and transported succinate at lower rates than did rod-shaped cells.     

Ac transposition in transgenic tomato plants

Summary As an initial step towards developing a transposon mutagenesis system in tomato, the maize transposable element Ac was transformed into tomato plants via Agrobacterium tumefaciens. Southern analysis of leaf tissue indicated that in nine out of eleven transgenic plants, Ac excised from the T-DNA and reintegrated into new chromosomal locations. The comparison of Ac banding pattern in different leaves of the same primary transformant provided evidnece for transposition during later stages of transgenic plant development. There was no evidence of Ds mobilization in tomato transformants.     

Role of special stains in the diagnosis of Pneumocystis carinii infection from bronchial washing specimens in patients with the acquired immune deficiency syndrome

Fifty bronchial washing specimens from 36 patients with acquired immune deficiency syndrome (AIDS) were retrospectively reviewed to assess the sensitivity of the various special stains used to diagnose Pneumocystis carinii. In 76% of the cases, the Diff-Quik stain was positive; it was the easiest and most rapid of the special stains used. The sensitivity was increased to 92%, 96% and 100%, respectively, by also doing cresyl echt violet, Grocott's Gomori methenamine silver and both the cresyl violet and Grocott stains in addition to the Diff-Quik stain. We conclude that the Diff-Quik stain is a fairly reliable and rapid screening procedure for making the diagnosis of Pneumocystis infection in bronchial washings from AIDS patients. The routine Papanicolaou stain gave less sensitive results in the smears of the washing specimens, but does give a markedly improved yield in bronchoalveolar lavage specimens.     

Effect of Light on the Metabolism of Lipids in the Rat Retina

The effect of light on the in vitro incorporation of a variety of radioactive precursors into glycerolipids was tested in isolated retinas of albino rats. There was an increase in the incorporation of [2-3H]myo-inositol, 32Pi, [2-3H]glycerol, and [methyl-3H]choline into retinal phospholipids in light compared to that in darkness. [2-3H]myo-Inositol was incorporated primarily into phosphatidylinositol. 32Pi was incorporated primarily into the phosphoinositides, although there were significant increases in the specific activities of all retinal phospholipids in light compared to those in darkness. Likewise, [2-3H]glycerol incorporation into all retinal phospholipids and diglycerides was greater in light than in the dark. There was no effect of light on the incorporation of [2-3H]ethanolamine into phosphatidylethanolamine or of [3-3H]serine into phosphatidylserine, although these phospholipids were labeled to a greater extent in light with [2-3H]glycerol. There was no effect of light on the incorporation of [3H]palmitic acid into diglycerides and phospholipids, with the exception of phosphatidylinositol. Light also had no effect on the uptake of [2-3H]glycerol, [2-3H]inositol, or [methyl-3H]choline into the retina. We conclude from these studies that light stimulates the phosphoinositide effect in the rat retina. Although some of the results are consistent with a stimulation of de novo synthesis of all lipid classes, our studies with [3H]palmitate, [2-3H]ethanolamine, and [3-3H]serine do not support this conclusion.(ABSTRACT TRUNCATED AT 250 WORDS)     

The sucrose fuel cell: Efficient biomass conversion using a microbial catalyst

Sucrose was used as a fuel in a thionine-mediated microbial fuel cell containingProteus vulgaris serving as the biocatalyst in the anode compartment. The measured yields show that under suitable conditions the substrate may be oxidised quantitatively to electricity and carbon dioxide.     

Differential expression of 2′∶3′-cyclic nucleotide 3′-phosphodiesterase in cultured central,peripheral, and extraneural cells

The relative levels of the central nervous system myelin marker enzyme 2:3-cyclic nucleotide 3-phosphodiesterase (EC 3.1.4.37, CNPase) were determined in neuroblastoma, astrocyte, oligodendrocyte and Schwann cell cultures and in freshly isolated human lymphocytes and platelets. The highest specific activities were associated with the cells that elaborate myelin membrane in the central and peripheral nervous system, oligodendrocytes and Schwann cells, respectively. Antiserum to bovine CNPase recognized both CNP1 and CNP2 in CNS myelin and human oligodendroglioma. In addition, a 53,000 dalton protein was evident on autoradiographs of immunoblotted PNS myelin and human oligodendroglioma proteins. Cultured rat oligodendrocyte, C₆ and mouse NA neuroblastoma CNPase appear to share common determinants with the corresponding normal rat CNS enzyme.     

Human lymphocytes treated with r-7,t-8-dihydroxy-t-9,10-epoxy-7,8,9,10-tetrahydrobenzo[a]pyrene require low-density lipoproteins for DNA excision repair

Human lymphocytes which were non-mitogen-stimulated, and which were depleted of lipoproteins, were found to be deficient in DNA excision repair typically initiated in these cells in response to treatment with a direct-acting polynuclear aromatic hydrocarbon carcinogen. Lymphocytes either depleted of lipoproteins or supplemented with human low-density lipoproteins formed DNA-carcinogen adducts which were not chromatographically distinguishable. The state of lipoprotein depletion did not alter lymphocyte uptake of thymidine from the medium. Lymphocytes which were depleted of lipoproteins, treated with carcinogen, and subsequently supplemented with low-density lipoproteins, regained the ability to engage in DNA excision repair. The data suggest that either low-density lipoprotein(s), or a component(s) of low-density lipoprotein(s), is required by human lymphocytes in order to initiate excision repair of carcinogen-damaged DNA.