The classical genetic map of Arabidopsis includes more than 130 genes with an embryo-defective (emb) mutant phenotype. Many of these essential genes remain to be cloned. Hundreds of additional EMB genes have been cloned and catalogued (www.seedgenes.org) but not mapped. To facilitate EMB gene identification and assess the current level of saturation, we updated the classical map, compared the p...

Introduction: Within the northern residual polar cap of Mars are dark lanes or troughs; on the walls of these exposures are layered deposits. These deposits consist of extensive lateral layers of ice and dust and are found throughout the polar cap. They were first identified in Mariner 9 images [1, 2] and later studied in detail with the Viking orbiters [e. g. 3, 4, 5, 6]. In these images, the ...

T paper in this issue of PNAS by Miranda-Rios et al. (1) demonstrates the importance of a conserved RNA structure in the regulation of genes involved in thiamin biosynthesis. Thiamin, also known as vitamin B1, is a cofactor for many important enzymes and therefore essential for growth. Bacteria have genes for all the enzymes necessary to synthesize thiamin, but if adequate amounts are present i...

IscA/SufA paralogues are the members of the iron-sulfur cluster assembly machinery in Escherichia coli. Whereas deletion of either IscA or SufA has only a mild effect on cell growth, deletion of both IscA and SufA results in a null-growth phenotype in minimal medium under aerobic growth conditions. Here we report that cell growth of the iscA/sufA double mutant (E. coli strain in which both iscA...

MATERIAL The sputa of five patients who had been confined at Howard Marcy Hospital for more than five years were collected. The diagnosis in all five patients was: far advanced pulmonary tuberculosis, active with sputum positive on smear and culture. In all patients, more than thm &ancc studies showed b a a resistant to isoniazid, PAS, smptomycin, ethionamide, pyrazinamide and cydoscrine. Clini...

Abstract C 20 H 15 F 5 N 2 O 3 , orthorhombic, Pbca (no. 61), a = 10.9913 (4) Å, b 11.0451(5) c 30.3925(14) V 3689.6 (3) Å Z 8, R gt ( ) 0.0360, wR ref 0.0927, T 170 K.

Thiamine pyrophosphate is an essential cofactor involved in central metabolism and amino acid biosynthesis and is derived from thiamine (vitamin B(1)). The extent to which this metabolite is available to bacterial pathogens replicating within host cells is still little understood. Growth studies using modified minimal Welshimer's broth (mMWB) supplemented with thiamine or the thiamine precursor...

Moraxella catarrhalis strain 25238 detoxified lipooligosaccharide (dLOS)-protein conjugates induced a significant rise of bactericidal anti-LOS antibodies in animals. This study reports the effect of active or passive immunization with the conjugates or their antiserum on pulmonary clearance of M. catarrhalis in an aerosol challenge mouse model. Mice were injected subcutaneously with dLOS-tetan...

We report the first seasonal time-series observa-tions of porewater composition obtained for deep-sea sedi-ments. We observed considerable temporal variability of O,,NO,-, and Mn2+ profiles at the French JGOFS site DYFA-MED (western Mediterranean) in response to a pulsed inputof organic matter. A delivery of reactive organic matter rep-resenting only 1% of the average or...

Vitamin B1, which consists of the vitamers thiamin and its phosphorylated derivatives, is an essential micronutrient for all living organisms because it is required as a metabolic cofactor in several enzymatic reactions. Genetic diversity of vitamin B1 biosynthesis and accumulation has not been investigated in major crop species other than rice and potato. We analyzed cassava germplasm for accu...