The lidgap-Gates (lg Ga) mutation for open eyelids at birth maps to mouse Chromosome 13

Complex nonadditive interactions between specific alleles at multiple loci may underlie many so-called multifactorial threshold birth defects. The open-eyelids-at-birth defect in mice is a good model for these defects, and an understanding of its genetic complexity begins with mapping the participating loci. The open-eyelids defect can be part of a syndrome or can occur with no other obvious phenotypic effects. Of the latter nonsyndromic forms, the lidgap series includes four extant mutations that are considered to be alleles based on complementation tests. All show genetic complexity in segregation ratios. None has been mapped previously. On the basis of a strategy of mapping the mutation with the simplest inheritance pattern first, we generated an extensive exclusion map for lidgap-Gates, lg ^Ga , using morphological and protein polymorphisms. We then screened the non-excluded regions in a congenic strain, AEJ.LGG—lg ^Ga , for SSLP markers and located the differential chromosome segment containing the lg ^Ga locus in a region near the distal end of mouse Chromosome (Chr) 13. This linkage was confirmed and refined by typing SSLPs in 64 F₂ and 74 BC₁ progeny of a cross of LGG/Bc (lg ^Ga /lg ^Ga ) to SWV/Bc. The lg ^Ga mutation maps to a 1- to 2-cM region between D13Mit76 and D13Mit53. Integrin alpha 1 and integrin alpha 2, which map to the same general region, are possible candidate loci, based on their embryonic expression and cellular function. Evidence is also presented for a common unlinked recessive suppressor of the open eyelids trait caused by lg ^Ga . Received: 3 February 1995 / Accepted: 19 February 1996     

Interspecific agonistic behaviour in small mammals in a Mexican high-elevational grassland

Field trials were conducted throughout an annual cycle to study the role of agonistic behaviour in explaining the relative abundance of the volcano mouse ( Neotomodon alstoni ) in a small mammal community in high-altitude grasslands of central Mexico. Intrasexual contests between N. alstoni and three other sympatric rodents ( Peromyscus melanotis, Microtus mexicanus, and Reithrodontomys megalotis ) were performed. Male and female P. melanotis (100 and 67% of contests, respectively) and M. mexicanus (82 and 100%) were aggressively dominant over N. alstoni , whereas R. megalotis (80 and 100%) were not aggressive. Agonistic behaviour in this species did not explain its greater abundance in the community.     

Direct acid-catalysed transmethylation of lactobacillic acid in lactic acid bacteria

Summary Cellular fatty acids inLactobacillus büchneri were transmethylated with H₂SO₄ catalyst in methanol at elevated temperature. By optimising the reaction time and the amounts of catalyst and methanol used at a fixed temperature it was possible to maximise the lactobacillic acid yield. The yield of lactobacillic acid with this method was better than with the traditional method using base-catalysed saponification followed by HCL-catalysed methylation.     

Genetic and Structural Analysis of Five Arabidopsis Mutants with Abnormal Root Morphology Generated by the Seed Transformation Method

A number of Arabidopsis thaliana mutants with abnormal rootmorphology have been isolated from a population of Agrobacterium-mediated seed transformants. Five of these mutants identifiedby their abnormal root morphology have been genetically andmorphologically characterised. Two mutants, 5905 and 1767 havedefective cellular elongation, mutant 7203 lacks an endodermalcell layer and mutants 4792 and 7133 exhibit abnormal radialcellular expansion. It is apparent from detailed analysis thatabnormal root morphology is accompanied by abnormal hypocotylphenotype. Genetic analysis has revealed that only one of thesemutants is tagged with a T-DNA insert.Copyright 1994, 1999 AcademicPress Arabidopsis thaliana, root, development, T-DNA insertion mutagenesis, endodermis, elongation     

Development of an arabinose-fermenting Zymomonas mobilis strain by metabolic pathway engineering.

The substrate fermentation range of the ethanologenic bacterium Zymomonas mobilis was expanded to include the pentose sugar, L-arabinose, which is commonly found in agricultural residues and other lignocellulosic biomass. Five genes, encoding L-arabinose isomerase (araA), L-ribulokinase (araB), L-ribulose-5-phosphate-4-epimerase (araD), transaldolase (talB), and transketolase (tktA), were isolated from Escherichia coli and introduced into Z. mobilis under the control of constitutive promoters that permitted their expression even in the presence of glucose. The engineered strain grew on and produced ethanol from L-arabinose as a sole C source at 98% of the maximum theoretical ethanol yield, based on the amount of consumed sugar. This indicates that arabinose was metabolized almost exclusively to ethanol as the sole fermentation product, with little by-product formation. Although no diauxic growth pattern was evident, the microorganism preferentially utilized glucose before arabinose, apparently reflecting the specificity of the indigenous facilitated diffusion transport system. This microorganism may be useful, along with the previously developed xylose-fermenting Z. mobilis (M. Zhang, C. Eddy, K. Deanda, M. Finkelstein, and S. Picataggio, Science 267:240-243, 1995), in a mixed culture for efficient fermentation of the predominant hexose and pentose sugars in agricultural residues and other lignocellulosic feedstocks to ethanol.