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1.
Background
Pathogenic Yersinia species (Y. enterocolitica, Y. pestis, Y. pseudotuberculosis) share a type three secretion system (TTSS) which allows translocation of effector proteins (called Yops) into host cells. It is believed that proteins are delivered through a hollow needle with an inner diameter of 2–3 nm. Thus transport seems to require substrates which are essentially unfolded. Recent work from different groups suggests that the Yersinia TTSS cannot accommodate substrates which are folded prior to secretion. It was suggested that folding is prevented either by co-translational secretion or by the assistance of specific Yop chaperones (called Sycs). 相似文献2.
Jong-Won Oh Jin-Ho Lee Kap-Soo Noh Hyune-Hwan Lee Jae-Heung Lee Hyung-Hwan Hyun 《Biotechnology letters》1991,13(10):727-732
Summary ThedapA gene (L-2,3-dihydrodipicolinate synthetase: DHDP synthetase) ofCorynebacterium
glutamicum JS231, a lysine overproducer, cloned and subcloned inE.
coli/C.
glutamicum shuttle vector pECCG117 was used to transformE.
coli threonine producer and threonine and lysine coproducer. The plasmid pDHDP5812 carryingdapA gene ofC.
glutamicum led to increase in lysine production in theseE.
coli strains. Threonine and lysine co-producerE.
coli TF1 with pDHDP5812 produced lysine with small amount of threonine. The DHDP synthetase activity ofE.
coli TF1 carrying pDHDP5812 showed high resistance toward inhibition by lysine. 相似文献
3.
Norma de Magalhães Erismann Ana M. Fernandez Jaime Baeza Juanita Freer Hector Mansilla Nelson Duran 《Biotechnology letters》1990,12(4):305-308
Summary We report the delignification ofPinus
radiata D Don,Eucalyptus
globulus andEucalyptus
grandis woods (formic acid treated and untreated) by 2 h treatment with a hemin/hydrogen peroxide system. The untreated chips and sawdust ofE.
globulus were 30% and 50% delignified respectively. No significant effects were found forP.
radiata sawdust;P.
radiata treated chips (organosolv pulp) did not show any further delignification upon hemin/peroxide action, 25% delignification was achieved in untreated chips. In the case ofE.
grandis untreated wood the delignification was better in sawdust than in chips, but in smaller percentage than in the otherEucalyptus species. This relation is maintained in substrates, treated with formic acid or untreated. The delignification of chips in both species ofEucalyptus was improved when they were pre-treated with formic acid. The loss of lignin in theE.
grandis andE.
globulus sawdust (pre-treated with formic acid) was 79% and 75% respectively. 相似文献
4.
In Saccharomyces cerevisiae, four proteins, Shu1, Shu2, Psy3 and Csm2, form a stable SHU-complex both in vivo and in vitro. These proteins are involved in the early stages of the homologous recombination DNA damage repair process. In this paper, the crystal structure of the Psy3–Csm2 sub-complex is presented at 1.8 Å resolution and successfully fitted into our small angle X-ray scattering (SAXS) data of the SHU-complex. Taken together with our electrophoretic mobility shift assay (EMSA) results, a model is proposed for the SHU–protein complex coupled with DNA.Structured summary of protein interactions:PSY3 and CSM2 bind by X-ray crystallography (View interaction) PSY3, CSM2, Shu 1 and Shu 2 physically interact by x ray scattering (View interaction) 相似文献
5.
Species specific shoot regeneration response of cotyledonary explants of Brassicas 总被引:11,自引:0,他引:11
A study of shoot regeneration from cotyledons of three basic diploid species of Brassica, B. campestris (AA), B. nigra (BB), B. oleracea (CC) and their amphidiploids B. juncea (AABB), B. napus (AACC) and B. carinata (BBCC) showed species-specific responses for in vitro shoot regeneration. Analysis of the species mean shoot regeneration response over a range of growth regulator combinations revealed that i) B. campestris is the lowest regenerating species, ii) B. nigra and B. oleracea regenerate with high frequencies, iii) In amphidiploids, the presence of B. campestris component brings down shoot regeneration frequency below the value of B. oleracea in B. napus combination and is additive of the combining genomes in B. juncea combination. In B. carinata regeneration frequencies are less than the parental diploid species, iv) Significant intraspecific genotypic differences were observed for B. nigra and B. oleracea among diploids and B. juncea and B. carinata among amphidiploids, when cotyledons of eighteen genotypes were tested in one growth regulator combination.Abbreviations MS
Murashige and Skoog (1962)
- NAA
-naphthalene acetic acid
- IAA
Indole 3-acetic acid
- BA
6-Benzyl aminopurine 相似文献
6.
D. R. Modi A. K. Singh K. S. Rao D. Chakravarty H. N. singh 《Biotechnology letters》1991,13(11):793-798
Summary Machete resistant (Mat
r), basalin resistant (Bas
r), 3(3,4 dichlorophenyl)-1,1-dimethyl urea resistant (DCMU
r), atrazine resistant (Atr
r) and propanil resistant (Prp
r) phenotypes ofGloeocapsa sp. were cotransformed toNostoc
muscorum at high frequency. Spontaneously occurring mutants of the multiple herbicide resistant transformant containing L-methionine-DL-sulfoximine resistant (Msx
r), ethylene diamine resistant (Eda
r), or phosphinothricin resistant (Ppt
r) glutamine synthetase (GS) showed extracellular liberation of ammonia resulting from fixation of N2 under photosynthetic conditions. Results suggest a definite role of GS activity in regulation of extracellular ammonia. 相似文献
7.
《Journal of molecular biology》2021,433(16):166894
β-barrel proteins are folded and inserted into outer membranes by multi-subunit protein complexes that are conserved across different types of outer membranes. In Gram-negative bacteria this complex is the barrel-assembly machinery (BAM), in mitochondria it is the sorting and assembly machinery (SAM) complex, and in chloroplasts it is the outer envelope protein Oep80. Mitochondrial β-barrel precursor proteins are translocated from the cytoplasm to the intermembrane space by the translocase of the outer membrane (TOM) complex, and stabilized by molecular chaperones before interaction with the assembly machinery. Outer membrane bacterial BamA interacts with four periplasmic accessory proteins, whereas mitochondrial Sam50 interacts with two cytoplasmic accessory proteins. Despite these major architectural differences between BAM and SAM complexes, their core proteins, BamA and Sam50, seem to function the same way. Based on the new SAM complex structures, we propose that the mitochondrial β-barrel folding mechanism follows the budding model with barrel-switching aiding in the release of new barrels. We also built a new molecular model for Tom22 interacting with Sam37 to identify regions that could mediate TOM-SAM supercomplex formation. 相似文献
8.
E. B. Doerschug 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1976,48(3):119-130
Summary Dotted (Dt) is the regulatory element of a two-unit controlling system in maize. Dt causes the inherited change from the recessive a (colorless) to its dominant allele, A (anthocyanin production), during the development of the stalk, leaves, and endosperm. The mutation events are observed as sectors of color in an anthocyaninless background.Since its discovery over 40 years ago, Dt has always been found in the terminal knob of the short arm of chromosome 9. This is puzzling because controlling and regulatory elements in general are not located permanently, but change positions (transpose) within the chromosomal complement. To resolve this seeming discrepancy, transpositions were looked for in a homozygous a Dt stock. Because the frequency of aleurone mutations is exponentially related to Dt dosage, a Dt transposition would result in a greatly increased number of dots if the egg or sperm nucleus contained both the transposed Dt and the Dt remaining on chromosome 9. A total of 6 transposed Dt's (Dt-T) were recovered in this manner.
Dt-TA was found linked to the gene Y (yellow endosperm) of chromosome 6. Dt-TB no longer showed linkage with yg2 of chromosome 9, but remains unlocated (the original Dt in this stock is separated from yg2 by 6 or 7 cross-over units.). The remaining transpositions (C-F) assorted independently of Dt on chromosome 9.The transposed Dt's had the same effect as Dt on the frequency and timing of aleurone mutations. An increase in transposition frequency and losses of Dt-T's was characteristic of several of the transposed Dt's. Dt-T's B-F transposed so frequently that testcross ratios of 71 (three Dt' s) and 15 1 (four Dt' s) were observed. No secondary transpositions or losses of Dt-TA were detected. Thus, Dt-TA resembles the original Dt with regard to its transposition frequency and stability.Journal Paper No. J-8333 of the Iowa Agriculture and Home Economics Experiment Station, Ames, Iowa. Project No. 1880. 相似文献
9.
Summary A 4.1-kb cryptic plasmid, designated pCA134, has been isolated fromClostridium species. In order to develop a vector suitable for transforming saccharolytic clostridia three hybrid plasmids were constructed by inserting pCA134 into pHV32 withEcoRI, orBglII andBamHI. The newly constructed plasmids were propagated inEscherichia
coli and were used to transformBacillus
subtilis andClostridium
acetobutylicum. One of them, pCAB32 (10.1 kb), which contains chloramphenicol acetyltransferase gene and an origin of replication derived from pCA134 was introduced intoB.subtilis andC.acetobutylicum as well asE.coli. 相似文献
10.
R. C. Wang G. H. Liang E. G. Heyne 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1977,51(3):139-142
Summary We observed pairing, when the ph gene was present, between wheat (Triticum aestivum L. em. Thell.) chromosome 4B, and an Agropyron intermedium (Host) Beauv. chromosome (Ai) carrying a gene resistant to wheat streak mosaic (WSM). In a monosomic addition polyhaploid [2n = 22 = 19' + 5B' (ph) + 4B' + Ai'], we recorded an average of 4.1 bivalents and 0.3 trivalents per cell. Induced homoeologous pairing was most effective when both 5B chromosomes carrying ph gene were present. Our data suggest that chromosome 4B of wheat and the Agropyron chromosome (Ai) carrying a gene for resistance to WSM are homoeologous and that it is possible to use either ph mutant or nullisomic 5B stock to induce genetic recombination between the two chromosomes.Contribution No. 1657-j, Kansas State Agric. Expt. Sta., Manhattan, KS. The research is partially supported by a grant from Kansas Wheat Commission 相似文献
11.
Summary Four diverse strains of Agrobacterium tumefaciens (C58, Ach5, GV3111, and A281) were capable of inducing tumors at a high frequency on inoculated stems of lentil (Lens culinaris Medik. cultivar Laird) in vivo, and on excised shoot apices in vitro. GV3111 and Ach5 produced the largest and heaviest tumors in vivo, while A281 produced the heaviest tumors in vitro. Tumor formation and opine production are indicative of plant cell transformation and tumors produced appropriate opines: nopaline (C58), octopine (Ach5 and GV3111), and agropine and mannopine (A281). Southern analysis of DNA from a tumor line produced by strain C58 showed that a T-DNA fragment had been transferred into the lentil genome. 相似文献
12.
Azurmendi HF Mitra S Ayala I Li L Finkielstein CV Capelluto DG 《Molecules and cells》2010,30(6):581-585
The Toll-interacting protein (Tollip) is a negative regulator of the Toll-like receptor (TLR)-mediated inflammation response.
Tollip is a modular protein that contains an Nterminal Tom1-binding domain (TBD), a central conserved domain 2 (C2), and a C-terminal coupling of ubiquitin to endoplasmic reticulum degradation (CUE) domain. Here, we report the sequence-specific backbone 1H, 15N, and 13C assignments of the human Tollip CUE domain. The CUE domain was found to be a stable dimer as determined by size-exclusion
chromatography and molecular crosslinking studies. Analysis of the backbone chemical shift data indicated that the CUE domain
exhibits three helical elements corresponding to 52% of the protein backbone. Circular dichroism spectrum analysis confirmed
the helical nature of this domain. Comparison of the location of these helical regions with those reported for yeast CUE domains
suggest differences in length for all helical elements. We expect the structural analysis presented here will be the foundation
for future studies on the biological significance of the Tollip CUE domain, its molecular interactions, and the mechanisms
that modulate its function during the inflammatory response. 相似文献
13.
Assimilation of cholesterol by some cultures of lactic acid bacteria and bifidobacteria 总被引:2,自引:0,他引:2
Summary Cultures ofStr.
thermophilus assimilated less cholesterol than those ofLactobacillus
delbrueckii subsp.bulgaricus. A significant difference was found between strains ofL.
delbrueckii subsp.bulgaricus — LB1 and LB2 and LB3 (p<0.001).Bif.
bifidum actively assimilated cholesterol, but no significant difference was observed between their two strains (p>0.05). Cultures ofL.
asidophilus assimilated significantly more cholesterol than those ofStr.
thermophilus and a commercial yoghurt culture. 相似文献
14.
N.I. Ghali E.J. Kattelman S.C. Hung K.E. Schnorf G.C. Le Breton D.L. Venton 《Prostaglandins & other lipid mediators》1984,27(6):865-876
Because of its highly unstable nature, TXA2, produced by platelet metabolism of arachidonic acid, does not lend itself to use as a receptor probe for its own receptor. As such, the stable TXA2/PGH2 antagonist, trans-13-azaprostanoic acid (trans-13-APA, 12b), was prepared as the [17,18 3H] derivative ([3H] trans-13-APA, 12c) to study this receptor and to better evaluate the mechanism of action of these azaprostanoids. Tritiated trans-13-APA, 12c, was prepared in nearly theoretical specific activity (57 Ci/mmole) from (17z)-trans-13-azaprost-17-enoic acid (11b) by catalytic tritiation. The unsaturated 11b was prepared by condensation of cis-7-amino-3-heptene (8) with 2-(6-carboxyhexyl) cyclopentanone (9), NaBH4 reduction, chromatography, and hydrolysis of the trans isomer so isolated. The olefins 11a and b were also of biochemical interest because of the unsaturation in the lower side chain. The presence of similar unsaturation in PGH3 (4) and TXA3 (3) renders these prostaglandins inactive as proaggregatory agents. Evaluation of the antiaggregatory activity of 11a and b indicated it to be about the same potency in inhibiting human platelet aggregation as the parent cis and trans-13-APAs, suggesting that introduction of a double bond at the 17 position in platelet prostaglandin antagonists is unlikely to result in enhanced antiplatelet activity. 相似文献
15.
S. G. Marakis 《Biotechnology letters》1992,14(11):1075-1080
Summary The ripe carob pod (pericarp) is rich in water-soluble sugars, mainly sucrose (63% on total sugars). Sucrose crystallization from aqueous carob extract is prevented by its reducing sugar content. The selective consumption of these sugars by mixed culture ofRhizopus
oligosporus andSaccharomyces
rouxii gives a sucrose syrup suitable for several uses e.g. sucrose extraction. 相似文献
16.
Krzysztof W. Pankiewicz Kyoichi A. Watanabe 《Nucleosides, nucleotides & nucleic acids》2013,32(5):613-624
Abstract Treatment of ψ-uridine (3) with α-acetoxyisobutyryl chloride in acetonitrile gave, after deprotection, a mixture of four products: 5-(2-chloro-2-deoxy-β-D-arabinofuranosyl)uracil (10a), its 3′-chloro xylo isomer (11a), 2′-chloro-2′-deoxy-ψ-uridine (9a) and 4,2′-anhydro-ψ-uridine (8a). Each component was isolated by column chromatography. Compound 9 was converted to the known 1,3-dimethyl derivative 2 by treatment with DMF-dimethylacetal. Treatment of 10 and 11 with NaOMe/MeOH afforded the same 4,2′-anhydro-C-nucleoside 8. The 1,3-dimethyl analogues of 10 and 11, however, were converted to 2′,3′-anhydro-1,3-dimethyl-ψ-uridine (13) upon base treatment. The epoxide 13 was also prepared in good yield by treatment of 10 and 11 with DMF-dimethylacetal. 相似文献
17.
Regulation of Escherichia coli phosphofructokinase in situ 总被引:15,自引:0,他引:15
The activity of E. coli phosphofructokinase in situ has been studied in cells permeabilized to its substrates, products and effectors by a toluene-freezing treatment. The in situ enzyme exhibits moderate cooperativity in respect to F6P (nH up to 2.0), rather low affinity for ATP (with Km up to 1 mM when saturated with F6P), activation by ADP, and inhibition, within the physiological range of concentrations, by high ATP and phosphoenolpyruvate. This behaviour of the enzyme in situ at concentrations of the effector metabolites as those reported in intact cells in glycolytic and gluconeogenic conditions could account for the changes of phosphofructokinase activity needed for metabolic regulation in vivo. 相似文献
18.
Summary Plasmids fromZ.
mobilis could be stably maintained inE.
coli HB101 in which the expression of various drug resistance markers could be monitored. A large molecular weight plasmid (5.2 kbp) ofZ.
mobilis was found to harbour the genes for mercuric chloride degradation and to confer uponE.
coli, resistance to a higher mercuric chloride concentration as compared toZ.
mobilis. The introduction of this plamsid madeE.
coli sensitive to concentrations of cadmium acetate which were originally non-inhibitory to it. 相似文献
19.
Summary Genetic determinants of the Muc+ character were investigated in two ropy strains,Lactobacillus delbrueckii ssp.bulgaricus 201 andL. casei ssp.casei NCIB 4114, which secrete a large amount of slime in culture media. Plasmid DNA analysis revealed the presence of two plasmids (4.5 and 2.3 Mdal) inL. casei ssp.casei, whileL. delbrueckii ssp.bulgaricus was plasmid free, suggesting a chromosomal location of Muc+ character in this strain. Curing experiments carried out onL. casei ssp.casei NCIB 4114 indicated a correlation between the Muc+ phenotype and the 4.5 Mdal plasmid. 相似文献
20.
Interspecific somatic hybrid plants betweenRudbeckia hirta cv. Marmalade andR.laciniata cv. Irish Eyes were regenerated following the electro-fusion of mesophyll protoplasts ofR.hirta with callus protoplasts ofR.laciniata. A hybrid selection scheme was based on the fact that plant regeneration, from parental protoplasts ofR.hirta, was via shoot regeneration of callus, and only via rhizogenesis forR.laciniata. The other half of the selection strategy was based on the presence of anthocyanin-pigmented roots; a characteristic of theR.hirta parent only. Somatic hybrids were regenerated, via rhizogenesis, alongside normalR.laciniata but were distinguished by the presence of pigmented roots (a feature ofR.hirta). Hybrid plants had a floral morphology that was intermediate as compared to that of the two parents, with an expected somatic chromosome number of 2n=(2x+4x)=74. Pollen viability though was low. Esterase and peroxidase isozyme profiles confirmed the hybrid nature of the regenerated plants with pigmented roots, whilst chloroplast DNA restriction analysis showed that these hybrids had aR.laciniata chloroplast DNA. This demonstration of somatic hybridisation not only opens up the possibility of incorporating novel traits between such ornamentalCompositae species, but provides a selection strategy based on rhizogenesis as the route to plant regeneration coupled with heritable pigmentation production of roots as a confirmatory hybrid marker.ABBREVIATIONS BSA
bovine serum albumin
- EDTA
ethylene diamine tetra acetic acid
- FDA
fluorescein diacetate
- f.wt.
fresh weight
- IAA
indole 3-acetic acid
- MS
Murashige and Skoog (1962) medium
- TEMED
N,N,N,N-Tetra methyl ethylene diamine
- TES
(N-tris (hydroxymethyl) methyl-2-aminoethanesulfonic acid) 相似文献