Genetic analysis of feed quality and seed weight of sorghum inbred lines and hybrids using analytical methods and NIRS

Eight lines of grain sorghum and their F1 hybrids were evaluated for contents of crude protein (CP), fat (FAT), and starch (STA); protein digestibility (PD); and in vitro dry matter disappearance (IVDMD). The effect of seed weight (SW) on these traits and the potential use of near infrared reflectance spectroscopy (NIRS) to predict them also were investigated. The male lines included three normal-seeded lines (TX2737, TX435, and P954063) and two largeseeded lines (PL-1 and Eastin1). The female lines included commonU.S. seed parent lines (Wheatland, Redlan, and SA3042). The lines and their hybrids were grown under dryland conditions at Kansas State University experiment fields in Ashland and Belleville, Kansas, in 1999. The experiments were conducted using a randomized complete block design with four replications at each location. The effect of genotype was significant for all measured traits. The male parent lines were highly variable and expressed high levels of genetic variation in combining ability for CP, PD, STA, and SW. The female parents were genetically more uniform; however, significant general combining ability effects were noted for PD and SW. Significant negative correlations were noted between CP and STA and between SW and STA. Significant positive correlations were found between CP and SW and between FAT and IVDMD. Crude protein content was predicted accurately by NIRS. Fat content and IVDMD could not be predicted by NIRS. The NIRS equations based on ground samples were more accurate than those based on whole-seed samples

Induction of amphibian oocyte maturation by polyvalent cations and alkaline pH in the absence of potassium ions

The maturation of Xenopus laevis oocytes was studied in media free of added potassium salts. Under these conditions maturation could be triggered by 1 mM Mn2+ and La3+ and, to a lesser extent, by 2-4 mM Ca2+ and Mg2+. Maturation induced by 1.5 mM Mn2+ was inhibited by K+ concentrations above 0.25 mM. Potassium was inhibitory when added up to 2 hr before germinal vesicle breakdown occurred. In potassium-free media, maturation could be induced by incubation of oocytes under mild alkaline media (pH 8.5-9). A high percentage of medium-sized oocytes (stage IV according to Dumont) was induced to mature by progesterone in the absence of potassium. Maturation of oocytes in potassium-free media was normal by the criteria of germinal vesicle breakdown, production of maturation promoting factor, vitelline membrane activation, and inhibition by known maturation inhibitors. © 1979

Population Improvement of Pearl Millet and Sorghum: Current Research, Impact and Issues for Implementation

Populations o f pearl millet and sorghum are being developed and improved fo r a variety o f purposes. In this paper, we present a global review o f current populations, their composition, and methods for improvement. The potential impact o f these programs is indicated by recent results regarding responses to recurrent selection and the linkages ofpopulation improvement with development o f lines and varieties in these two crops. Recent research on generating interpool populations and modeling responses to alternative recurrent selection methods are presented fo r population improvement o f pearl millet

Infection of Kissing Bugs with Trypanosoma cruzi, Tucson, Arizona, USA

A survey of triatomine insects found that 41.5% were infected with the causative agent of Chagas disease

Engineered Protein Nano-Compartments for Targeted Enzyme Localization

Compartmentalized co-localization of enzymes and their substrates represents an attractive approach for multi-enzymatic synthesis in engineered cells and biocatalysis. Sequestration of enzymes and substrates would greatly increase reaction efficiency while also protecting engineered host cells from potentially toxic reaction intermediates. Several bacteria form protein-based polyhedral microcompartments which sequester functionally related enzymes and regulate their access to substrates and other small metabolites. Such bacterial microcompartments may be engineered into protein-based nano-bioreactors, provided that they can be assembled in a non-native host cell, and that heterologous enzymes and substrates can be targeted into the engineered compartments. Here, we report that recombinant expression of Salmonella enterica ethanolamine utilization (eut) bacterial microcompartment shell proteins in E. coli results in the formation of polyhedral protein shells. Purified recombinant shells are morphologically similar to the native Eut microcompartments purified from S. enterica. Surprisingly, recombinant expression of only one of the shell proteins (EutS) is sufficient and necessary for creating properly delimited compartments. Co-expression with EutS also facilitates the encapsulation of EGFP fused with a putative Eut shell-targeting signal sequence. We also demonstrate the functional localization of a heterologous enzyme (β-galactosidase) targeted to the recombinant shells. Together our results provide proof-of-concept for the engineering of protein nano-compartments for biosynthesis and biocatalysis

Insight into Coenzyme A cofactor binding and the mechanism of acyl-transfer in an acylating aldehyde dehydrogenase from Clostridium phytofermentans

The breakdown of fucose and rhamnose released from plant cell walls by the cellulolytic soil bacterium Clostridium phytofermentans produces toxic aldehyde intermediates. To enable growth on these carbon sources, the pathway for the breakdown of fucose and rhamnose is encapsulated within a bacterial microcompartment (BMC). These proteinaceous organelles sequester the toxic aldehyde intermediates and allow the efficient action of acylating aldehyde dehydrogenase enzymes to produce an acyl-CoA that is ultimately used in substrate-level phosphorylation to produce ATP. Here we analyse the kinetics of the aldehyde dehydrogenase enzyme from the fucose/rhamnose utilisation BMC with different short-chain fatty aldehydes and show that it has activity against substrates with up to six carbon atoms, with optimal activity against propionaldehyde. We have also determined the X-ray crystal structure of this enzyme in complex with CoA and show that the adenine nucleotide of this cofactor is bound in a distinct pocket to the same group in NAD(+). This work is the first report of the structure of CoA bound to an aldehyde dehydrogenase enzyme and our crystallographic model provides important insight into the differences within the active site that distinguish the acylating from non-acylating aldehyde dehydrogenase enzymes