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1.
Novel rhamnolipid-producing strains of three thermophilic bacteria, Thermus sp., T. aquaticus and Meiothermus ruber were identified that have not been previously described as rhamnolipid producers. Rhamnolipids were extracted from supernatant
and further purified by thin-layer chromatography. Mass spectrometry with negative electrospray ionization revealed 77 rhamnolipid
homologues varying in chain length and unsaturation. Tandem mass spectrometry identified mono-rhamnolipid and di-rhamnolipid
homologues containing one or two 3-hydroxy-fatty acids, saturated, monounsaturated or diunsaturated, even- or odd-chain, up
to unusual long chains with 24 carbon atoms. The stereochemistry of rhamnose was L and that of 3-hydroxy-fatty acids was R, the position of double bonds in monoenoic acids was cis ω-9. All three strains produced a rhamnolipid that differs in structure from Pseudomonas aeruginosa rhamnolipids and exhibits excellent surfactant properties. Importantly, in comparison to P. aeruginosa both strains, i.e., Thermus and Meiothermus, are Biosafety level 1 microorganisms and are not pathogenic to humans. 相似文献
2.
ANGUSTIFOLIA (AN), a plant homolog of C-terminal binding protein, controls the polar elongation of leaf cells and the trichome-branching pattern in Arabidopsis thaliana. In the present study, degenerate PCR was used to isolate an ortholog of AN, referred to as LgAN, from larch (Larix gmelinii). The LgAN cDNA is predicted to encode a protein of 646 amino acids that shows striking sequence similarity to AN proteins from other plants. The predicted amino acid sequence has a conserved NAD-dependent 2-hydroxy acid dehydrogenase (D2-HDH) motif and a plant AN-specific LxCxE/D motif at its N-terminus, as well as a plant-specific long C-terminal region. The LgAN gene is a single-copy gene that is expressed in all larch tissues. Expression of the LgAN cDNA rescued the leaf width and trichome-branching pattern defects in the angustifolia-1 (an-1) mutant of Arabidopsis, showing that the LgAN gene has effects complementary to those of AN. These results suggest that the LgAN gene has the same function as the AN gene. 相似文献
3.
Ae-Young Mo Bora Kwon Seralathan Kamala-Kannan Kui-Jae Lee Byung-Taek Oh Dae-Hyuk Kim Moon-Sik Yang Jin-Hyung Kim Seung-Moon Park 《World journal of microbiology & biotechnology》2010,26(6):1099-1105
Bacteria of the Bacillus species have been reported as an important microorganism in fermented soybean products. In the present study, thirty Bacillus isolates were screened from Meju, a Korean soybean fermentation starter. The comparative analysis of 16S rDNA sequences, 16S-23S internal transcribed spacer
sequences, phenotypic, and biochemical characterizations revealed three phylogenetically distinct groups namely Bacillus atrophaeus,
Bacillus polyfermenticus and Bacillus subtilis. The isolates were assayed for poly-γ-glutamate production and fibrinolytic activity. Among the isolates, B. polyfermenticus exhibited maximum poly-γ-glutamate production and fibrinolytic activity. Moreover, the soybean products fermented by B. polyfermenticus have increased the time taken for coagulation and hemorrhage in mice. The results of the present study clearly indicate the
functional role of B. polyfermenticus in fermented soybean products. 相似文献
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P. Selvakumar S. Rajasekar K. Periasamy N. Raaman 《World journal of microbiology & biotechnology》2008,24(10):2125-2131
Melanins are enigmatic pigments that are produced by a wide variety of microorganisms including several species of bacteria
and fungi. For more than 40 years, fungi have been known to produce pigments called melanins. Melanin pigment production by
mushrooms was not intensively studied. The present study was carried out on isolation and characterization of melanin from
an edible mushroom Pleurotus
cystidiosus var. formosensis. The mushroom produced dark mucous mass of hyaline arthrospores on mycelium. The coremia exclusively produced dikaryotic
arthrospores with the remnant of a clamp connection. Continuous cell extension and division in the coremium stipe supplied
cells for arthroconidiation at the coremium apex, which is surrounded by a liquid droplet (coremioliquid). The black coloured
coremea (conidia) were produced by Antromycopsis macrocarpa (anamorph of P. cystidiosus) when cultured on potato dextrose agar medium. The agar plate was incubated at continuous light illumination for high amount
of pigment (coremea) production. The slimy layer of the coremea was extracted and partially purified by alkaline and acid
treatment. The black pigment was confirmed as melanin based on UV, IR and EPR spectra apart from chemical analysis. This is
the first report on characterization of melanin obtained from Pleurotus
cystidiosus var. formosensis. 相似文献
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A. Ahantarig W. Trinachartvanit N. Chauvatcharin P. Kittayapong V. Baimai 《Folia microbiologica》2008,53(6):547-550
Wolbachia are maternally inherited symbiotic bacteria capable of inducing an extensive range of reproductive abnormalities in their
hosts, including cytoplasmic incompatibility (CI). Its density (concentration) is likely to influence the penetrance of CI
in incompatible crosses. The variations of Wolbachia density could also be linked with phage WO density. We determined the relative density (relative concentration) of prophage
WO orf7 and Wolbachia (phage-to-bacteria ratio) during early developmental and adult stages of singly infected Aedes albopictus mosquito (Wolbachia A-infected) by using real-time quantitative PCR. Phage WO and Wolbachia did not develop at the same rate. Relative Wolbachia density (bacteria-to-host ratio) was high later in development (adult stages) whilst relative prophage WO density (phage-to-bacteria
ratio) was low in the adult stages. Furthermore, 12-d-old adults of singly infected female mosquito had the highest Wolbachia density. In contrast, the larval stage 4 (L4) contained the highest prophage WO-B orf7 density. The association of hosts-Wolbachia-phage among diverse species is different. Thus, if phage and Wolbachia are involved in CI mechanism, the information of this association should be acquired for each specific type of organism for
future use of population replacement or gene drive system. 相似文献
9.
Wen-bin Liao Meng-bin Ruan Bai-ming Cui Nan-fei Xu Jia-ju Lu Ming Peng 《Plant Growth Regulation》2009,58(1):35-45
The aim of the investigation reported here was to assess the role of gibberellin in cotton fiber development. The results
of experiments in which the gibberellin (GA) biosynthesis inhibitor paclobutrazol (PAC) was tested on in vitro cultured cotton
ovules revealed that GA is critical in promoting cotton fiber development. Plant responses to GA are mediated by DELLA proteins.
A cotton nucleotide with high sequence homology to Arabidopsis thaliana
GAI (AtGAI) was identified from the GenBank database and analyzed with the BLAST program. The full-length cDNA was cloned from upland
cotton (Gossypium hirsutum, Gh) and sequenced. A comparison of the putative protein sequence of this cDNA with all Arabidopsis DELLA proteins indicated that GhRGL is a putative ortholog of AtRGL. Over-expression of this cDNA in Arabidopsis plants resulted in the dwarfed phenotype, and the degrees of dwarfism were related to the expression levels of GhRGL. The deletion of 17 amino acids, including the DELLA domain, resulted in the dominant dwarf phenotype, demonstrating that
GhRGL is a functional protein that affects plant growth. Real-time quantitative PCR results showed that GhRGL mRNA is highly expressed in the cotton ovule at the elongation stage, suggesting that GhRGL may play a regulatory role in cotton fiber elongation. 相似文献
10.
Jian-Xia Zhang Kun-Lin Wu Li-Ning Tian Song-Jun Zeng Jun Duan 《Acta Physiologiae Plantarum》2011,33(2):409-417
11.
D. J. Goyder 《Kew Bulletin》2008,63(2):331-333
Summary
Funastrum rupicola Goyder, a new species of Apocynaceae: Asclepiadoideae from Bolivia, is described and illustrated. The conservation status of this species is assessed. 相似文献
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Two repeated DNA sequences isolated from a partial genomic DNA library of Helianthus annuus, p HaS13 and p HaS211, were shown to represent portions of the int gene of a Ty3 /gypsy retroelement and of the RNase-Hgene of a Ty1 /copia retroelement, respectively. Southern blotting patterns obtained by hybridizing the two probes to BglII- or DraI-digested genomic DNA from different Helianthus species showed p HaS13 and p HaS211 were parts of dispersed repeats at least 8 and 7 kb in length, respectively, that were conserved in all species studied. Comparable hybridization patterns were obtained in all species with p HaS13. By contrast, the patterns obtained by hybridizing p HaS211 clearly differentiated annual species from perennials. The frequencies of p HaS13- and p HaS211-related sequences in different species were 4.3x10(4)-1.3x10(5) copies and 9.9x10(2)-8.1x10(3) copies per picogram of DNA, respectively. The frequency of p HaS13-related sequences varied widely within annual species, while no significant difference was observed among perennial species. Conversely, the frequency variation of p HaS211-related sequences was as large within annual species as within perennials. Sequences of both families were found to be dispersed along the length of all chromosomes in all species studied. However, Ty3 /gypsy-like sequences were localized preferentially at the centromeric regions, whereas Ty1/ copia-like sequences were less represented or absent around the centromeres and plentiful at the chromosome ends. These findings suggest that the two sequence families played a role in Helianthusgenome evolution and species divergence, evolved independently in the same genomic backgrounds and in annual or perennial species, and acquired different possible functions in the host genomes. 相似文献
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Bacteria with the ability to grow on nitrogen-free media and with nitrogenase activity under aerobic or microaerobic conditions were isolated from sugarcane roots collected from four different agricultural locations in Granada (Spain). Isolates were Gram negative rods and were identified as Azotobacter chroococcum and Azospirillum brasilense. Our results suggest that Azotobacter isolates do not have a particular affinity for sugarcane rhizospheres and that, on the contrary, Azospirillum isolates show specific association and perhaps endophytic colonization of sugarcane. However, obligate endophytes (Gluconacetobacter diazotrophicus) were not found in the apoplastic fluid of the stems and macerates extracts of sugarcane tissues with the procedure applied. Population of this microorganism might be in low number in the Spanish sugarcane varieties studied which is also discussed. 相似文献
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Beibei Huang Xiaojun Liu Xinglong Wang Yan Pi Juan Lin Jiong Fei Xiaofen Sun Kexuan Tang 《Molecular Biology》2005,39(5):684-695
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Noel H. Holmgren 《Brittonia》2018,70(1):115-139
A revision of Penstemon sect. Saccanthera subsect. Serrulati includes a new species (P. salmonensis), a new variety (P. triphyllus var. infernalis), and the elevation of a subspecies to species (P. curtiflorus), bringing the total number of species to eight, which are keyed and described, complete with nomenclature and type citations. 相似文献
19.
Amanita concentrica sp. nov. is described from an evergreen broad-leaved forest of Chiba Prefecture with Castanopsis cuspidata var. sieboldii and Quercus glauca. The fungus is a medium to large, white to yellowish-white mushroom characterized by many pyramidal warts on pileus, striate
margin of pileus, distinct ascending concen-tric rings at upper part of stipe bulb, and inamyloid basidiospores. It is considered
to belong to the section Amanita.
Received: March 30, 2001 / Accepted: October 1, 2001 相似文献
20.
Perugini LD Murphy JP Marshall D Brown-Guedira G 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2008,116(3):417-425
Powdery mildew is an important foliar disease in wheat, especially in areas with a cool or maritime climate. A dominant powdery
mildew resistance gene transferred to the hexaploid germplasm line NC99BGTAG11 from T. timopheevii subsp. armeniacum was mapped distally on the long arm of chromosome 7A. Differential reactions were observed between the resistance gene in
NC99BGTAG11 and the alleles of the Pm1 locus that is also located on chromosome arm 7AL. Observed segregation in F2:3 lines from the cross NC99BGTAG11 × Axminster (Pm1a) demonstrate that germplasm line NC99BGTAG11 carries a novel powdery mildew resistance gene, which is now designated as Pm37. This new gene is highly effective against all powdery mildew isolates tested so far. Analyses of the population with molecular
markers indicate that Pm37 is located 16 cM proximal to the Pm1 complex. Simple sequence repeat (SSR) markers Xgwm332 and Xwmc790 were located 0.5 cM proximal and distal, respectively, to Pm37. In order to identify new markers in the region, wheat expressed sequence tags (ESTs) located in the distal 10% of 7AL that
were orthologous to sequences from chromosome 6 of rice were targeted. The two new EST-derived STS markers were located distal
to Pm37 and one marker was closely linked to the Pm1a region. These new markers can be used in marker-assisted selection schemes to develop wheat cultivars with pyramids of powdery
mildew resistance genes, including combinations of Pm37 in coupling linkage with alleles of the Pm1 locus. 相似文献