Biolistic introduction of a synthetic Bt gene into elite maize

Summary A synthetic Bt gene encoding a truncated version of the CryIA(b) protein derived from Bacillus thuringiensis was successfully introduced into elite maize using microprojectile bombardment of immature embryos. The method used to initiate and identify transformation events is described. We describe the detailed parameters used for the Biolistics device as well as the plasmids used for the transformations. The plasmids contained the synthetic Bt gene driven by either the 35S CaMV promoter or a combination of two tissue-specific promoters, leaf and pollen, derived from maize. Specific conditions for the culture of Type I callus from immature embryos, the phosphinothricin (PPT) selection protocol, and the regeneration of plants are discussed. T0 and T1 plants were initially identified using the pH-dependent chlorophenol red test and/or the histochemical -glucuronidase (GUS) assay. PCR and Southern data confirm the presence of the 35S CaMV promoter and the synthetic Bt gene.     

Variation in the expression of self-fertility inLolium perenne L.

Summary A series of experiments was conducted to determine the variations arising between replicate selfing units, to compare self-fertility and cross-fertility in the same environment and to measure the variation in expression of self-fertility by different techniques and in different environments.Variation in self-fertility between selfing units within genotypes was relatively high, representing approximately one-third of the total observed variation in a series of duplicate selfings of over 60 genotypes tested in one environment. In order to differentiate clearly between the self-fertility of a limited number of genotypes as many as four replicates were needed, although this number varied with the environment in which the tests were conducted. Levels of self-fertility were similar in bag selfing units placed inside or outside a glasshouse in an average year, but were greater outside than inside in a year which was drier and warmer than average. In a highly humid environment the mean level of self-fertility attained was reduced by a factor of three. Removal of flag leaf laminae had an adverse effect on self-fertility, reducing it by half. Shaking the pollination bags, as is the usual practice to promote pollen dispersal, increased self-fertility very considerably over that of unshaken controls. Assisting pollen dispersal by blowing filtered air into the bags was time-consuming and did not prove to be superior to the shaking technique. It is clear that self-fertility can neither be considered in isolation from the environment in which it is determined, nor can it justifiably be related to cross-fertility unless both are determined in the same environment. A sample of over 60 genotypes tested in one environment was on average 2.2% as self-fertile as they were cross-fertile, with a range for individual genotypes from 0–31%. Optimum conditions for maximum expression of self-fertility, essential in the exploitation of this character in ryegrass breeding, have yet to be fully established.     

Glomalin in aggregate size classes from three different farming systems

Glomalin was measured in soil from farming systems managed for 8 years by chisel tillage (CT), more intensive tillage for organic (ORG) production, and no tillage (NT) on Acrisols (FAO Soil Units) in the Mid-Atlantic region of the U.S. Whole soil and aggregate size classes of >2.00, 0.50–2.00 and 0.21–0.50 mm (macroaggregates), 0.05–0.21 mm (microaggregates), and <0.05 mm (fine material) were examined. Glomalin-related soil protein (GRSP) was extracted from 1-g samples (four plots per treatment) with 100 mM sodium pyrophosphate, pH 9.0, at 121 °C in three extraction cycles. Extracts were pooled and quantified by using the Bradford protein assay. Concentrations of GRSP and total carbon (C) in aggregates were linearly related across aggregate size classes for all treatments (GRSP = 0.101C + 0.56, r² = 0.95). No tillage had significantly greater whole soil GRSP than did CT or ORG (P = 0.01). Mean values for GRSP in aggregates of NT were higher than for CT or ORG aggregates by 0.53 and 0.66 mg g⁻¹ aggregates, respectively. There were no differences among treatments in GRSP concentrations in fine material. In NT the concentration of GRSP increased as aggregate size increased in contrast to the disturbed treatments, CT or ORG, where there were no differences in GRSP concentration across aggregate size fractions. Larger proportions of GRSP were distributed in macroaggregates of NT compared to CT and ORG in contrast to larger proportions in microaggregates of CT and ORG than in NT. Although soil disturbance in ORG farming is greater than for CT farming, both treatments had similar GRSP concentrations and distributions.     

Mapping QTL for seed yield and canning quality following processing of black bean (<Emphasis Type="Italic">Phaseolus vulgaris</Emphasis> L.)

Quantitative trait loci (QTL) analysis was conducted to identify QTL for seed yield and color retention following processing of a recombinant inbred line (RIL) black bean population. A population of 96 RILs were derived from the cross of black bean cultivars ‘Jaguar’ and 115M and evaluated in replicated trials at one location over 4 years (2004–2007) in Michigan. A 119-point genetic map constructed using simple sequence repeat (SSR), sequence related amplified polymorphism (SRAP), target region amplified polymorphism (TRAP) and phenotypic markers spanned fifteen linkage groups (LG) or 460 cM of the bean genome. Fourteen QTL for yield and color retention in four environments were identified by composite interval mapping on six linkage groups. A major QTL SY10.2^J115 for seed yield was identified on LG B10 with additional QTL on B3, B5, and B11. Color retention following processing was associated with loci on B1, B3, B5, B8, and B11. 115M possessed positive alleles for yield, but negative alleles for color retention. Some QTL for yield and color retention co-localized with regions identified in previous studies while others, particularly for color retention, were unique. Additional QTL for agronomic and canning quality traits were detected and individual contributions to future black bean breeding are discussed.     

THE ROLE OF "FOLIC ACID" AND BIOTIN IN THE UTILIZATION OF PANTOTHENIC ACID BY THE RAT

The addition of succinylsulfathiazole to highly purified diets containing all dietary factors known to be required by the rat, including pantothenic acid, results in the appearance of signs of severe pantothenic acid deficiency, including achromotrichia and porphyrin-caked whiskers. These changes are accompanied by a marked reduction in the pantothenic acid content of the liver, and are corrected by the inclusion in such diets of crystalline biotin and "folic acid" concentrates. The utilization of pantothenic acid by the rat appears to depend on the availability of biotin and "folic acid." Under normal conditions these are supplied by the diet and synthesized by intestinal bacteria. A hypothesis is offered in explanation of the chromotrichial actions of "folic acid," biotin and p-aminobenzoic acid.     

The crystal structure of a sodium galactose transporter reveals mechanistic insights into Na+/sugar symport

Membrane transporters that use energy stored in sodium gradients to drive nutrients into cells constitute a major class of proteins. We report the crystal structure of a member of the solute sodium symporters (SSS), the Vibrio parahaemolyticus sodium/galactose symporter (vSGLT). The approximately 3.0 angstrom structure contains 14 transmembrane (TM) helices in an inward-facing conformation with a core structure of inverted repeats of 5 TM helices (TM2 to TM6 and TM7 to TM11). Galactose is bound in the center of the core, occluded from the outside solutions by hydrophobic residues. Surprisingly, the architecture of the core is similar to that of the leucine transporter (LeuT) from a different gene family. Modeling the outward-facing conformation based on the LeuT structure, in conjunction with biophysical data, provides insight into structural rearrangements for active transport.     

Hormonal termination of larval diapause in Dermacentor albipictus

The molting hormone, alpha-ecdysone, and an analog triangle up(7)-5beta-cholestene-2beta,3beta, 14alpha-triol-6-one when applied externally, terminates diapause in larvae of the winter tick, Dermacentor albpictus. This is the first reported hormonal termination of diapause in an arthropod other than an insect.