Effects of acetic,propionic, and butyric acids on rice seedling growth and nutrition

Summary Soils which are flooded for lowland rice culture shift from aerobic to anaerobic organic matter transformations. Anaerobic carbon transformations, involving chiefly rice crop residues, are characterized by the formation of various organic acids. These may accumulate after prolonged incubations in amounts sufficient to be toxic to developing rice seedlings. In these experiments the effects of acetic, propionic, and butyric acids were studied at 1, 5, and 10 mN on the growth and nutrition of 14 day old (Oryza sativa L.) cultivar Earlirose rice seedlings. Nutrient solutions were used in the experiments with pH controlled at 6.5 in one experiment and in another the acid concentrations were allowed to attain equilibrium pH with the nutrient solution (1 mN=4.6, 5 mN=3.9, and 10 mN=3.8).Root elongation of rice seedlings was decreased by increased organic acid concentrations at both pH's. New root initiation was totally inhibited at all organic acid concentrations at equilibrium pH, and at 10 mN with pH 6.5. New root initiation at 1 and 5 mN at pH 6.5 allowed increased seedling dry matter production, whereas it was reduced in all other treatments. Plant height and weight were also decreased by increased acid concentrations. At pH 6.5 the plants showed no specific symptoms of organic acid toxicity except reduced growth. At equilibrium pH values specific symptoms were observed. At 1 mN, the seedlings withered, similar to desiccation; at 5 mN the leaf tips showed symptoms similar to bronzing; and at 10 mN the seedlings died after 24 hours.Uptake of both P and K by roots were reduced by increased concentrations of all organic acids at both pH's. P concentration and total uptake were reduced in the shoots with all treatments, whereas the effects on K in shoots were not consistent.The magnitude of organic acid toxicity is a function of the kind, concentration and the degree of dissociation of the acid. Increased media pH reduces the toxicity of the acid concentrations.Contribution from the Department of Agronomy and Range Science, University of California, Davis, California 95616.Contribution from the Department of Agronomy and Range Science, University of California, Davis, California 95616.     

Regioselective synthesis of isoxazole–mercaptobenzimidazole hybrids and their in vivo analgesic and anti-inflammatory activity studies

Regioselective synthesis of isoxazole–mercaptobenzimidazole hybrids and their efficiency in in vivo analgesic and anti-inflammatory activity was described. A comparison of structure–activity relationship for there compounds was also emphasized.     

Glucosylation of Isoflavonoids in Engineered Escherichia coli

A glycosyltransferase, YjiC, from Bacillus licheniformis has been used for the modification of the commercially available isoflavonoids genistein, daidzein, biochanin A and formononetin. The in vitro glycosylation reaction, using UDP-α-D-glucose as a donor for the glucose moiety and aforementioned four acceptor molecules, showed the prominent glycosylation at 4′ and 7 hydroxyl groups, but not at the 5^th hydroxyl group of the A-ring, resulting in the production of genistein 4′-O-β-D-glucoside, genistein 7-O-β-D-glucoside (genistin), genistein 4′,7-O-β-D-diglucoside, biochanin A-7-O-β-D-glucoside (sissotrin), daidzein 4′-O-β-D-glucoside, daidzein 7-O-β-D-glucoside (daidzin), daidzein 4′, 7-O-β-D-diglucoside, and formononetin 7-O-β-D-glucoside (ononin). The structures of all the products were elucidated using high performance liquid chromatography-photo diode array and high resolution quadrupole time-of-flight electrospray ionization mass spectrometry (HR QTOFESI/MS) analysis, and were compared with commercially available standard compounds. Significantly higher bioconversion rates of all four isoflavonoids was observed in both in vitro as well as in vivo bioconversion reactions. The in vivo fermentation of the isoflavonoids by applying engineered E. coli BL21(DE3)/ΔpgiΔzwfΔushA overexpressing phosphoglucomutase (pgm) and glucose 1-phosphate uridyltransferase (galU), along with YjiC, found more than 60% average conversion of 200 μM of supplemented isoflavonoids, without any additional UDP-α-D-glucose added in fermentation medium, which could be very beneficial to large scale industrial production of isoflavonoid glucosides.     

WsSGTL1 gene from Withania somnifera,modulates glycosylation profile,antioxidant system and confers biotic and salt stress tolerance in transgenic tobacco

Glycosylation of sterols, catalysed by sterol glycosyltransferases (SGTs), improves the sterol solubility, chemical stability and compartmentalization, and helps plants to adapt to environmental changes. The SGTs in medicinal plants are of particular interest for their role in the biosynthesis of pharmacologically active substances. WsSGTL1, a SGT isolated from Withania somnifera, was expressed and functionally characterized in transgenic tobacco plants. Transgenic WsSGTL1-Nt lines showed an adaptive mechanism through demonstrating late germination, stunted growth, yellowish-green leaves and enhanced antioxidant system. The reduced chlorophyll content and chlorophyll fluorescence with decreased photosynthetic parameters were observed in WsSGTL1-Nt plants. These changes could be due to the enhanced glycosylation by WsSGTL1, as no modulation in chlorophyll biogenesis-related genes was observed in transgenic lines as compared to wildtype (WT) plants. Enhanced accumulation of main sterols like, campesterol, stigmasterol and sitosterol in glycosylated form was observed in WsSGTL1-Nt plants. Apart from these, other secondary metabolites related to plant’s antioxidant system along with activities of antioxidant enzymes (SOD, CAT; two to fourfold) were enhanced in WsSGTL1-Nt as compared to WT. WsSGTL1-Nt plants showed significant resistance towards Spodoptera litura (biotic stress) with up to 27 % reduced larval weight as well as salt stress (abiotic stress) with improved survival capacity of leaf discs. The present study demonstrates that higher glycosylation of sterols and enhanced antioxidant system caused by expression of WsSGTL1 gene confers specific functions in plants to adapt under different environmental challenges.     

BAsE-Seq: a method for obtaining long viral haplotypes from short sequence reads

Epidemiologists aim to inform the design of public health interventions with evidence on the evolution, emergence and spread of infectious diseases. Sequencing of pathogen genomes, together with date, location, clinical manifestation and other relevant data about sample origins, can contribute to describing nearly every aspect of transmission dynamics, including local transmission and global spread. The analyses of these data have implications for all levels of clinical and public health practice, from institutional infection control to policies for surveillance, prevention and treatment. This review highlights the range of epidemiological questions that can be addressed from the combination of genome sequence and traditional ‘line lists’ (tables of epidemiological data where each line includes demographic and clinical features of infected individuals). We identify opportunities for these data to inform interventions that reduce disease incidence and prevalence. By considering current limitations of, and challenges to, interpreting these data, we aim to outline a research agenda to accelerate the genomics-driven transformation in public health microbiology.     

Development and interspecific transferability of genic microsatellite markers in Spartina spp. with different genome size

Flow cytometry analysis showed variation of nuclear DNA content among different species of Spartina. Spartina alterniflora had the biggest genome (1763.9 Mbp) and S. cynosuroides had the smallest genome (756.35 Mbp), whereas the genomes of S. patens (969.36 Mbp) and S. spartinae (979.78 Mbp) were comparable. Mining simple sequence repeats (SSR) from 1227 expressed sequence tags (EST) generated from salt stressed S. alterniflora showed an abundance of di- and tri-nucleotide repeats. Of 100 ESSR (EST-derived SSR) loci with five or more repeats, 81 loci were successfully amplified in eight S. alterniflora genotypes and 15 (22.2%) ESSR markers were polymorphic. Eleven of the 15 polymorphic ESSRs showed amplification across six different species of Spartina while 100% cross transferability was observed with at least one species of Spartina. The average number of alleles per marker was 3.9 and 5.8 within S. alterniflora and among Spartina species, respectively. The ESSR markers discriminated different members within and between species of Spartina genus.     

Evidence of a humoral immune response against the prokaryotic expressed N-terminal autoprotease (N<Superscript>pro</Superscript>) protein of bovine viral diarrhoea virus

Bovine viral diarrhoea virus (BVDV) is an economically important pathogen of cattle and sheep belonging to the genus Pestivirus of the family Flaviviridae. Although the BVDV non-structural N-terminal protease (N^pro) acts as an interferon antagonist and subverts the host innate immunity, little is known about its immunogenicity. Hence, we expressed a recombinant BVDV N^pro-His fusion protein (28 kDa) in E. coli and determined the humoral immune response generated by it in rabbits. The antigenicity of the N^pro protein was confirmed by western blot using anti-BVDV hyperimmune cattle, sheep and goat serum, and anti-N^pro rabbit serum. When rabbits were immunized with the N^pro protein, a humoral immune response was evident by 4 weeks and persisted till 10 weeks post immunization as detected by ELISA and western blot. Despite N^pro-specific antibodies remaining undetectable in 80 serum samples from BVDV-infected sheep and goats, BVDV hyperimmune sera along with some of the field cattle, sheep and goat sera with high BVDV neutralizing antibody titres were found positive for N^pro antibodies. Our results provide evidence that despite the low immunogenicity of the BVDV N^pro protein, a humoral immune response is induced in cattle, sheep and goats only with repeated BVDV exposure.     

Atomic force microscopy in vitro study of surface roughness and fractal character of a dental restoration composite after air-polishing

Background  

Surface roughness is the main factor determining bacterial adhesion, biofilm growth and plaque formation on the dental surfaces in vivo. Air-polishing of dental surfaces removes biofilm but can also damage the surface by increasing its roughness. The purpose of this study was to investigate the surface damage of different conditions of air-polishing performed in vitro on a recently introduced dental restorative composite.