Chrysonila sitophila (TFB-27441): A hyperlignolytic strain

Summary C. sitophila strain TFB-27441 showed 2–3 times higher lignolytic activity thanPhanerochaete chrysosporium (BKM-F-1767 strain). Lignin had a marked effect on the ligninase activity indicating that some induction or activation mechanism is involved in lignin degradation byC. sitophila.     

Purification of restriction endonuclease XcyI from Xanthomonas cyanopsidis

A new Type II restriction endonuclease XcyI, purified from Xanthomonas cyanopsidis 13D5, is an isoschizomer of SmaI and XmaI that cleaves at the nucleotide sequence 5'-C decreases CCGGG-3' of double-stranded DNA. The single restriction activity present in this strain permits rapid purification of 8000 units of cleavage activity from 10 g of freshly harvested cells. The resulting XcyI preparation is free of contaminating nuclease activities that interfere with in vitro manipulation of DNA.     

Mapping quantitative trait loci for root development under hypoxia conditions in soybean (<Emphasis Type="Italic">Glycine max</Emphasis> L. Merr.)

Key message

Greatest potential, QTLs for hypoxia and waterlogging tolerance in soybean roots were detected using a new phenotypic evaluation method.

Abstract

Waterlogging is a major environmental stress limiting soybean yield in wet parts of the world. Root development is an important indicator of hypoxia tolerance in soybean. However, little is known about the genetic control of root development under hypoxia. This study was conducted to identify quantitative trait loci (QTLs) responsible for root development under hypoxia. Recombinant inbred lines (RILs) developed from a cross between a hypoxia-sensitive cultivar, Tachinagaha, and a tolerant landrace, Iyodaizu, were used. Seedlings were subjected to hypoxia, and root development was evaluated with the value change in root traits between after and before treatments. We found 230 polymorphic markers spanning 2519.2 cM distributed on all 20 chromosomes (Chrs.). Using these, we found 11 QTLs for root length (RL), root length development (RLD), root surface area (RSA), root surface area development (RSAD), root diameter (RD), and change in average root diameter (CARD) on Chrs. 11, 12, 13 and 14, and 7 QTLs for hypoxia tolerance of these root traits. These included QTLs for RLD and RSAD between markers Satt052 and Satt302 on Chr. 12, which are important markers of hypoxia tolerance in soybean; those QTLs were stable between 2 years. To validate the QTLs, we developed a near-isogenic line with the QTL region derived from Iyodaizu. The line performed well under both hypoxia and waterlogging, suggesting that the region contains one or more genes with large effects on root development. These findings may be useful for fine mapping and positional cloning of gene responsible for root development under hypoxia.

     

Changes in some innate defence parameters of seabream (Sparus aurata L.) induced by retinol acetate

The effects of high doses of dietary or intraperitoneally (i.p.) injected retinol acetate on the gilthead seabream (Sparus aurata L.) innate immune system were studied. Gilthead seabream specimens were fed a commercial non-supplemented diet containing 1.75 mg of vitamin A kg(-1) (as control) or the same diet supplemented with 50, 150 or 300 mg of retinol acetate kg(-1) (as vitamin A source). After 1, 2, 4 or 6 weeks, serum samples and head-kidney leucocytes were obtained from each fish. Serum lysozyme activity and myeloperoxidase (MPO) content were unaffected by the vitamin A diet content. The phagocytic and respiratory burst activities of head-kidney leucocytes were established, as well as their myeloperoxidase content. While phagocytosis was not enhanced by dietary vitamin A intake and was even slightly decreased after 2 weeks, respiratory burst activity was enhanced in specimens fed supplements of 150 and 300 mg retinol acetate kg(-1) diet for 1 or 2 weeks. Leucocyte MPO content was also enhanced when seabream were fed the highest vitamin A dose for 2 or 4 weeks and after being fed the 150 or 50 mg supplemented diets for 4 or 6 weeks, respectively. Three different groups of seabream were i.p. injected with 1 ml of phosphate buffer containing an amount of retinol acetate equivalent to the daily dietary supplements from the first experiment (0-control-, 0.05 or 0.30 mg 100 g(-1) biomass). Both injection doses of retinol acetate were toxic for the gilthead seabream which showed hypervitaminic effects. These data show that retinol acetate plays an important role in the gilthead seabream nonspecific cellular immune system due to its antioxidant properties. They also point to the importance of the way in which it is administered, by dietary uptake or intraperitoneal injection.     

Boron,copper, iron,manganese and zinc contents in leaves of flowering sunflower plants (Helianthus annuus,L.), grown with different boron supplies

Summary Boron, copper, iron, manganese and zinc concentrations were measured in sunflower leaves from plants grown hydroponically in a closed continuous flow system and with boron concentrations ranging from deficient to toxic. Leaves were analyzed at the stage of flower development. There was a highly significant inverse correlation between B concentration in solution and Mn concentration in leaves. Cu, Fe and Zn concentrations in the leaves were not changed by the different B levels, although the B concentration in leaves increased with an increasing concentration in solution, showing a close correlation each other.     

A guinea-pig hereditary cataract contains a splice-site deletion in a crystallin gene

A congenital cataract present in guinea pigs provided a unique opportunity to study a hereditary lens diseases at the molecular level. ζ-crystallin, one of the most abundant guinea pig lens proteins, was found to be altered in the lens of cataractous animals. Several ζ-crystallin cDNA clones were isolated from a cataractous lens library and found to contain a 102-bp deletion towards the 3′ end of the coding region. The deletion does not interfere with the reading frame but results in a protein 34 amino acids shorter. Sequence analysis of a normal genomic ζ-crystallin clone revealed that the missing 102-bp fragment corresponds to an entire exon (exon 7). PCR analysis of the genomic DNA isolated from cataractous animals showed that exon 7, though missing from the mRNA, is intact in the cataractous genome. Further sequence analysis of the α-crystallin gene disclosed a dinucleotide delection of the universal AG at the acceptor splice-site of intron 6 of the mutant gene. The presence of this mutation results in the skipping of exon 7 during the mRNA processing which in turn results in the altered ζ-crystallin protein. This if the first time a genomic mutation in an enzyme/crytallin gene has been directly linked to a congenital cataract.     

Effect of 2,4,6-trichlorophenol on the microbial activity of adapted anaerobic granular sludge bioaugmented with Desulfitobacterium strains

The anaerobic degradation of 2,4,6-trichlorophenol (246TCP) has been studied in batch experiments. Granular sludges previously acclimated to 2,4-dichlorophenol (24DCP) and then adapted to at a load of 330 μM 246TCPd(-1) in two expanded granular sludge bed (EGSB) reactors were used. One of the reactors had been bioaugmented with Desulfitobacterium strains whereas the other served as control. 246TCP was tested at concentrations between 250 and 760 μM. The study focused on the fate of both fermentation products and chlorophenols derived from dechlorination of 246TCP. This compound mainly affected the biodegradation of acetate and propionate, which were inhibited at 246TCP concentrations above 380 μM. Lactate and ethanol were also accumulated at 760 μM 246TCP. Methanogenesis was strongly inhibited at 246TCP concentrations higher than 380 μM. A diauxic production of methane was observed, which can be described by a kinetic model in which acetoclastic methanogenesis was inhibited, whereas hydrogenotrophic methanogenesis was hardly affected by 246TCP. The similarity of the kinetic parameters obtained for the control and the bioaugmented sludges (K(i)=175-200 μM 246TCP and n=7) suggests that methanogenesis is not affected by the bioaugmentation. Moreover, the 246TCP dechlorination occurred mainly at ortho position, successively generating 24DCP and 4-chlorophenol (4CP), which was identified as final product. The bioaugmentation does not significantly improve the anaerobic biodegradation of 246TCP. It has been shown that the active biomass is capable of bioaccumulating 246TCP and products from dechlorination, which are subsequently excreted to the bulk medium when the biomass becomes active again. A kinetic model is proposed which simultaneously explains 246TCP and 24DCP reductive dechlorinations and includes the 246TCP bioaccumulation. The values of the kinetic parameters for 246TCP dechlorination were not affected by bioaugmentation (V(max)=5.3 and 5.1 μM h(-1) and K(s)=5.8 and 13.1 μM for control and bioaugmented sludges, respectively).     

The reciprocal exclusion by L-dopa (L-3,4-dihydroxyphenylalanine) and L-tyrosine of their incorporation as single units into a soluble rat brain protein.

Several compounds, structurally and metabolically related to phenylalanine and tyrosine, were tested for their effects on the incorporations of phenylalanine and tyrosine as single units into a protein of the soluble subcellular fraction of rat brain. Of the compounds tested, only L-dopa (L-3,4-dihydroxyphenylalanine) inhibited these incorporations. Further, L-dopa was incorporated into a protein of the same fraction in such a way that it excluded the incorporation of tyrosine as a single unit. Conversely, tyrosine inhibited and excluded the incorporation of L-dopa. The incorporation of L-dopa required ATP (apparent Km = 0.23mM), KCl (apparent Km = 20mM) and MgCl2 (optimal concentration range, 5-16mM). These requirements were similar to those previously determined for the incorporation of tyrosine and phenylalanine. The inactivation rate of the enzymic systems for L-tyrosine and L-dopa incorporations, when kept at 37 degrees C, was the same for both amino acids (half-life = 80 min). It is suggested that the acceptor for the incorporation of dopa is the same as that for the incorporation of tyrosine.