Dimorphism in methane seep-dwelling ecotypes of the largest known bacteria

We present evidence for a dimorphic life cycle in the vacuolate sulfide-oxidizing bacteria that appears to involve the attachment of a spherical Thiomargarita-like cell to the exteriors of invertebrate integuments and other benthic substrates at methane seeps. The attached cell elongates to produce a stalk-like form before budding off spherical daughter cells resembling free-living Thiomargarita that are abundant in surrounding sulfidic seep sediments. The relationship between the attached parent cell and free-living daughter cell is reminiscent of the dimorphic life modes of the prosthecate Alphaproteobacteria, but on a grand scale, with individual elongate cells reaching nearly a millimeter in length. Abundant growth of attached Thiomargarita-like bacteria on the integuments of gastropods and other seep fauna provides not only a novel ecological niche for these giant bacteria, but also for animals that may benefit from epibiont colonization.     

Human hepatic triglyceride lipase: cDNA cloning, amino acid sequence and expression in a cultured cell line

By immunoscreening of a human cDNA expression library and hybridization of colonies, four partially overlapping cDNA clones of human hepatic triglyceride lipase (HTGL) mRNA were isolated. The clones included the complete coding sequence, the 3'- and at least part of the 5'-untranslated region. The length of the composite HTGL cDNA segment (1.7 kb) was consistent with the size of the mRNA identified in an established human hepatoma cell line. DNA-sequence analysis of cDNAs of partially unspliced mRNAs, and of cloned genomic DNA indicated that the HTGL coding sequence comprises at least six exons. As predicted from the cDNA, the unprocessed HTGL protein has a molecular weight of 56, three potential glycosylation sites, and a signal peptide of 23 amino acids. Sequence comparison with cDNA of other lipases, including rat hepatic lipase, revealed 30%-75% protein-sequence homology. The data establish that HTGL is a secretory protein produced in the hepatocyte, and that its synthesis can be continued in permanent cell lines of hepatoma origin. Our studies also showed that HTGL is another member of a lipase gene family which has interfacial binding sites and possibly other functional domains in common.     

Gibberellins in immature seeds and dark-grown shoots of Pisum sativum

Gibberellins (GAs) A₁₇, A₁₉, A₂₀, A₂₉, A₄₄, 2OH-GA₄₄ (tentative) and GA₂₉-catabolite were identified in 21-day-old seeds of Pisum sativum cv. Alaska (tall). These GAs are qualitatively similar to those in the dwarf cultivar Progress No. 9 with the exception of GA₁₉ which does not accumulate in Progress seeds. There was no evidence for the presence of 3-hydroxylated GAs in 21 day-old Alaska seeds. Dark-grown shoots of the cultivar Alaska contein GA₁, GA₈, GA₂₀, GA₂₉, GA₈-catabolite and GA₂₉-catabolite. Dark-grown shoots of the cultivar Progress No.9 contain GA₈, GA₂₀, GA₂₉ and GA₂₉-catabolite, and the presence of GA₁ was strongly indicated. Quantitation using GAs labelled with stable isotope showed the level of GA₁ in dark-grown shoots of the two cultivars to be almost identical, whilst the levels of GA₂₀, GA₂₉ and GA₂₉-catabolite were significantly lower in Alaska than in Progress No. 9. The levels of these GAs in dark-grown shoots were 10²- to 10³-fold less than the levels in developing seeds. The 2-epimer of GA₂₉ is present in dark-grown-shoot extracts of both cultivars and is not thought to be an artefact.Abbreviations cv cultivar - GA_n gibberellin A_n - GC gas chromatography - GC-MS combined gas chromatographymass spectrometry - HPLC high-pressure liquid chromatography - KRI Kovats retention index - MeTMSi methyl ester trimethylsilyl ether     

Internode length in Pisum. Estimation of GA1 levels in genotypes Le, le and led

The levels of GA₁, 3-epiGA₁ and GA₈ in genotypes Le, le and le^d of Pisum sativum L. were determined by gas chromatography-selected ion monitoring (GC-SIM) after feeds of [³H, ¹³C]-GA₂₀ to each genotype. The levels of endogenous and [¹³C]-labelled metabolites were determined by reverse isotope dilution with unlabelled GA₁, 3-epiGA₁ and GA₈. The results demonstrate a quantitative relationship between the level of GA₁ and the extent of elongation both on a per plant and a per g fresh weight basis. These results are consistent with previous findings in peas and other species possessing a predominant early 13-hydroxylation pathway for GA biosynthesis.
The levels of 3-epiGA₁ also decreased in the genotypic sequence Le, le, le^d although not as rapidly as for the level of GA₁. This may suggest that the alleles at the le locus also influence the formation of 3-epiGA₁.     

Metabolism of gibberellins by immature barley grain

Gibberellins A₁, A₄, A₉, A₁₂-aldehyde, A₂₀ and A₅₁, each labelled with both a radioactive and stable isotope were fed to immature barley grain by injection into the endosperm. After 7 d, extensive metabolism of all substrates had occurred, and metabolites were identified by combined capillary gas chromatography-mass spectrometry. A proposed scheme of gibberellin metabolism in immature barley grain is presented.Abbreviations GA_n gibberellin A_n - GC-MS combined gas chromatography-mass spectrometry - HPLC high-performance liquid chromatography     

Gibberellin A13 7-aldehyde: A proposed intermediate in the fungal biosynthesis of gibberellin A3

Gibberellin A₁₃ 7-aldehyde, previously proposed as an intermediate in the fungal biosynthesis of gibberellin A₃, has been prepared from gibbere     

Dilution of Liquid Rhizobium Cultures To Increase Production Capacity of Inoculant Plants

Experiments were undertaken to test whether peat-based legume seed inoculants, which are prepared with liquid cultures that have been deliberately diluted, can attain and sustain acceptable numbers of viable rhizobia. Liquid cultures of Rhizobium japonicum and Rhizobium phaseoli were diluted to give 10⁸, 10⁷, or 10⁶ cells per ml, using either deionized water, quarter-strength yeast-mannitol broth, yeast-sucrose broth, or yeast-water. The variously diluted cultures were incorporated into gamma-irradiated peat, and the numbers of viable rhizobia were determined at intervals. In all of the inoculant formulations, the numbers of rhizobia reached similarly high ceiling values by 1 week after incorporation, irrespective not only of the number of cells added initially but also of the nature of the diluent. During week 1 of growth, similar multiplication patterns of the diluted liquid cultures were observed in two different peats. Numbers of rhizobia surviving in the various inoculant formulations were not markedly different after 6 months of storage at 28°C. The method of inoculant preparation did not affect the nitrogen fixation effectiveness of the Rhizobium strains.