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1.
Dana Bernátová 《Biologia》2008,63(2):175-176
The paper brings information on an isolated occurrence and morphological characters of Carex × involuta and C. juncella populations in the Vel’ká Fatra Mts. Their presence has been known neither from the territory of Slovakia nor from the whole
Western Carpathians till now. 相似文献
2.
The lipase Lip2 of the edible basidiomycete, Pleurotus sapidus, is an extracellular enzyme capable of hydrolysing xanthophyll esters with high efficiency. The gene encoding Lip2 was expressed
in Escherichia coli TOP10 using the gene III signal sequence to accumulate proteins in the periplasmatic space. The heterologous expression under
control of the araBAD promoter led to the high level production of recombinant protein, mainly as inclusion bodies, but partially
in a soluble and active form. A fusion with a C-terminal His tag was used for purification and immunochemical detection of
the target protein. This is the first example of a heterologous expression and periplasmatic accumulation of a catalytically
active lipase from a basidiomycete fungus. 相似文献
3.
Despite the widespread distribution of Astyanax bockmanni in streams from Upper Paraná River system in central, southeastern, and southern Brazil, just recently, it has been identified
as a distinct Astyanax species. Cytogenetic studies were performed in two populations of this species, revealing conservative features. A. bockmanni shows 2n = 50 chromosomes, a karyotypic formula composed of 10 M + 12SM + 12ST + 16A and multiple Ag-NORs. Eight positive signals
in subtelocentric/acrocentric chromosomes were identified by fluorescent in situ hybridization (FISH) with 18S rDNA probes.
After FISH with 5S rDNA probes, four sites were detected, comprising the interstitial region of a metacentric pair and the
terminal region on long arms of another metracentric pair. Little amounts of constitutive heterochromatin were observed, mainly
distributed at distal region in two chromosomal pairs. Additionally, heterochromatin was also located close to the centromeres
in some chromosomes. No positive signals were detected in the chromosomes of A. bockmanni by FISH with the As-51 satellite DNA probe. The studied species combines a set of characteristics previously identified in
two different Astyanax groups. The chromosomal evolution in the genus Astyanax is discussed. 相似文献
4.
Black nightshades are a group of species best known for their ‘poisonous’ or noxious weedy reputation. It is not so well known
that species of this group serve as emerging food source in many countries worldwide especially in the African continent.
Despite the fact that the section has recently been studied extensively, taxonomy is still unsettled and debated because of
inter- and intraspecific hybridization, phenotypic plasticity and polyploidization. In this study we analyze the genetic relationships
among diploid, tetraploid and hexaploid species of sect. Solanum, which have possibly taken part in the formation of Solanum nigrum, utilizing multi-locus (SCoT, ISSR) markers combined with chloroplast trnL-F sequence data and morphological characters. We scored 51 morphological characters united with SCoT (171), ISSR (224) and
trnL-F (1042), for simultaneous analysis of 49 terminals and 1488 characters. The topology of the tree is concordant with the results
of the network analysis. In the phylogenetic networks, all the accessions of the diploid species shared a split with all of
the polyploid species. This reflected a high portion of shared ISSR and SCoT bands between diploids and polyploids. In addition,
a strong split divided the diploid species. The history of S. nigrum might be reticulate with hybrid speciation playing an important rule. Genetically differentiated diploids in few combinations
have created a series of genetically distinct polyploid populations. The insufficient isolation that permitted further recombination
between ancient polyploids and diploids have resulted in high level of genotypic and phenotypic polymorphism. This high level
of novel genomic variability obviously enabled species to succeed in their new environment. 相似文献
5.
6.
Matías Maggi Natalia Damiani Sergio Ruffinengo David De Jong Judith Principal Martín Eguaras 《Experimental & applied acarology》2010,50(3):269-279
We undertook a field study to determine whether comb cell size affects the reproductive behavior of Varroa destructor under natural conditions. We examined the effect of brood cell width on the reproductive behavior of V. destructor in honey bee colonies, under natural conditions. Drone and worker brood combs were sampled from 11 colonies of Apis mellifera. A Pearson correlation test and a Tukey test were used to determine whether mite reproduction rate varied with brood cell
width. Generalized additive model analysis showed that infestation rate increased positively and linearly with the width of
worker and drone cells. The reproduction rate for viable mother mites was 0.96 viable female descendants per original invading
female. No significant correlation was observed between brood cell width and number of offspring of V. destructor. Infertile mother mites were more frequent in narrower brood cells. 相似文献
7.
Much attention has been focused on the study of lactoferrin at the protein or nucleotide level in mice, humans, and cattle, but little is known about it in goats. The goat LF gene from 5' UTR to exon 17 was amplified, and the variation of g.7605C→T in 10 Chinese indigenous goat breeds was analyzed. Among the three ruminant species (cattle, sheep, and goats), the intron-exon distribution pattern was similar, and all the exons had the same length, but the length of introns varied greatly due to insertions or deletions. The frequency of allele T at g.7605C→T (50.12%) was a little higher than that of allele C (49.88%), and the genotype distribution differed greatly between goat populations. The g.7605C→T site showed higher genetic diversity in goat populations. The genetic differentiation was 0.0783, and gene flow was 2.9433 among the 10 Chinese indigenous goat populations. 相似文献
8.
Background
The presence of β-lactamases in Y. enterocolitica has been reported to vary with serovars, biovars and geographical origin of the isolates. An understanding of the β-lactamases in other related species is important for an overall perception of antibiotic resistance in yersiniae. The objective of this work was to study the characteristics of β-lactamases and their genes in strains of Y. intermedia and Y. frederiksenii, isolated from clinical and non-clinical sources in India. 相似文献9.
Recombinant Zantedeschia aethiopica agglutinin (ZAA) was expressed in Escherichia coli as N-terminal His-tagged fusion. After induction with isopropylthio-β-d-galactoside (IPTG), the recombinant ZAA was purified by metal-affinity chromatography. The purified ZAA protein was applied
in anti-fungal assay and the result showed that recombinant ZAA had anti-fungal activity towards leaf mold (Fulvia fulva), one of the most serious phytopathogenic fungi causing significant yield loss of crops. This study suggests that ZAA could
be an effective candidate in genetic engineering of plants for the control of leaf mold. 相似文献
10.
Heike Helmholz Blair D. Johnston Christiane Ruhnau Andreas Prange 《Hydrobiologia》2010,645(1):223-234
Scyphozoan medusae are very successful foragers which occasionally occur in high abundances in boreal waters and may impact
many different groups in the marine ecosystem by means of a variety of toxins. A rainbow trout gill cell line, RTgill-W1,
was tested for its suitability as quantitative indicator of the cytotoxicity of Cyanea capillata and Aurelia aurita; the major scyphozoan species in the North and Baltic seas. Cultures of rainbow trout gill cells were exposed to whole venoms
extracted from fishing tentacles and oral arms at increasing protein concentrations. The venom caused detachment, clumping
and lysis of cells, as well as a drop in vitality, in a dose-dependent manner. Morphological changes in the cells were evident
within 1 h after venom addition. The damage to gill cells was quantified by measuring the metabolic activity of the cells
by means of the fluorescence of resorufin derived from the nonfluorescent substrate, resazurin. In general, a decrease in
the metabolic activity of the cells was detected at a venom (protein) concentration above 2.0 μg ml−1 (corresponding to 0.2 μg 104 cells−1), and a total loss of activity was observed above 40.0 μg ml−1 (corresponding to 4.0 μg 104 cells−1). C. capillata venoms had increased cytotoxic activity as compared to A. aurita venoms at the same concentration. Cnidocyst extracts from oral arms of A. aurita induced an 85% loss of gill cell viability at concentrations of 0.2 μg 104 cells−1, whereas crude venoms from fishing tentacles reduced cell viability by 18% at the same concentration. Gel electrophoresis
of the venoms indicated that these consist of a large number of proteins in a fairly wide size range, from 6 to 200 kDa, including
some that are the same size as those found in cubomedusae. It also appears that larger (i.e., older) medusae have more complex
venoms and, in some cases, more potent venoms than smaller animals. 相似文献
11.
Pueyo A Figueiras AM Benito C 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2002,104(4):513-517
The menadione reductase (MNR), the nicotinamide adenine dinucleotide dehydrogenase (NDH) and diaphorase (DIA) isozymes were
studied in the allohexaploid Triticum aestivum cv ”Chinese Spring” and in five diploid Triticeae species. The Mnr1, Ndh3 and Dia1 loci were located on the chromosome arms 3AL, 3BL and 3DL of T. aestivum, respectively. These loci were also located on the 3H chromosome of Hordeum vulgare cv ”Betzes”, the 3L chromosome of Aegilops longissima and the 6RL chromosome arm of Secale cereale cv ”Imperial”. The chromosomal location results together with the segregation studies support a tetrameric behaviour of the
MNR1, NDH3 and DIA1 isozymes. The Ndh1 and Dia3 loci were located on homoeologous group 4 showing a monomeric behaviour. The chromosomal locations and linkage data of the
Mnr, Ndh and Dia loci suggest that Mnr1=Ndh3=Dia1; Ndh1=Dia3 and Ndh2=Dia2.
Received: 3 June 2001 / Accepted: 11 July 2001 相似文献
12.
The genus Pseudomonas has gone through many taxonomic revisions over the past 100 years, going from a very large and diverse group of bacteria
to a smaller, more refined and ordered list having specific properties. The relationship of the Pseudomonas genus to Azotobacter vinelandii is examined using three genomic sequence-based methods. First, using 16S rRNA trees, it is shown that A. vinelandii groups within the Pseudomonas close to Pseudomonas aeruginosa. Genomes from other related organisms (Acinetobacter, Psychrobacter, and Cellvibrio) are outside the Pseudomonas cluster. Second, pan genome family trees based on conserved gene families also show A. vinelandii to be more closely related to Pseudomonas than other related organisms. Third, exhaustive BLAST comparisons demonstrate that the fraction of shared genes between A. vinelandii and Pseudomonas genomes is similar to that of Pseudomonas species with each other. The results of these different methods point to a high similarity between A. vinelandii and the Pseudomonas genus, suggesting that Azotobacter might actually be a Pseudomonas. 相似文献
13.
To facilitate molecular genetic studies of Streptomyces ambofaciens that produces spiramycin, a commercially important macrolide antibiotic used in human medicine against Gram-positive pathogenic
bacteria, the conditions for the conjugal transfer of DNA from E. coli to S. ambofaciens were established using a bacteriophage ϕC31 att/int system. The transconjugation efficiency of S. ambofaciens varied with the medium used; the highest frequency was obtained on AS-1 medium containing 10 mM MgCl2 without heat treatment of the spores. In addition, by cloning and sequencing the attB site, we identified that S. ambofaciens contains a single attB site within an ORF coding for a pirin homolog, and its attB site sequence shows 100% nt identity to the sequence of S. coelicolor and S. lividans, which have the highest efficiency in transconjugation using the ϕC31 att/int system. 相似文献
14.
Chaoyi Liu Huanwen Xu Jing Jiang Sui Wang Guifeng Liu 《Plant Cell, Tissue and Organ Culture》2018,132(1):191-199
15.
16.
Nathaniel Liddy Peter E. Molloy Alan D. Bennett Jonathan M. Boulter Bent K. Jakobsen Yi Li 《Molecular biotechnology》2010,45(2):140-149
Previously, we have described the use of phage display to generate high affinity disulfide bond-linked T cell receptors (TCRs).
The affinities of the mutant TCRs were analysed after refolding of separately expressed α and β chains from Escherichia coli inclusion bodies. This approach is only suitable for the analysis of small numbers of TCR variants. An attractive alternative
would be soluble expression within the bacterial periplasm, but the generic production of TCRs within the E. coli periplasm has so far not proved successful. Here we show that functional, soluble TCR can be produced within the cytoplasm
of trxB gor mutant E. coli strains, with maximum yields of 3.4 mg/l. We also investigated the effect of coexpressing the folding modulators Skp and
DsbC finding that the TCR expression levels were largely unaffected by these chaperones. Importantly, we demonstrated that
the amount of protein purified from 50 ml starter cultures was sufficient to show functionality of the TCR by specific antigen
binding in both ELISA and surface plasmon resonance (SPR) assays. This TCR production method has the potential to allow rapid
and medium throughput analysis of affinity-matured TCRs selected from TCR phage display libraries. 相似文献
17.
Yali Xu Amrita Yasin Thomas Wucherpfennig C. Perry Chou 《World journal of microbiology & biotechnology》2008,24(12):2827-2835
Functional expression of heterologous Pseudozyma antarctica lipase B (PalB) in the periplasm of Escherichia coli was explored using four fusion tags, i.e. DsbC, DsbA, maltose-binding protein (MBP), and FLAG in the sequence of increasing
expression efficacy. Amongst these fusion tags, FLAG and MBP appear to be the most effective ones in terms of boosting enzyme
activity and enhancing solubility of PalB, respectively. Overexpression of these PalB fusions often resulted in concomitant
formation of insoluble inclusion bodies. Coexpression of a selection of periplasmic folding factors, including DegP (and its
mutant variant of DegPS210A), FkpA, DsbA, DsbC, and a cocktail of SurA, FkpA, DsbA, and DsbC, could improve the expression performance. Coexpression
of DsbA appeared to be the most effective in reducing the formation of inclusion bodies for all the four PalB fusions, implying
that functional expression of PalB could be limited by initial bridging of disulfide bonds. Culture performance was optimized
by overexpressing FLAG-PalB with DsbA coexpression, resulting in a high volumetric PalB activity of 360 U/L. 相似文献
18.
Hubert J Dolecková-Maresová L Hýblová J Kudlíková I Stejskal V Mares M 《Experimental & applied acarology》2005,35(4):281-291
The stored-product mites are the most abundant and frequent group of pests living on the stored food products in Europe. They endanger public health since they produce allergens and transmit mycotoxin-producing fungi. Novel acaricidal compounds with inhibitory effects on the digestive enzymes of arthropods are a safe alternative to the traditional neurotoxic pesticides used for control of the stored-product pests. In this work, we explored the properties of acarbose, the low molecular weight inhibitor of -amylases (AI), as a novel acaricide candidate for protection of the stored products from infestation by Acarus siro (Acari: Acaridae). In vitro analysis revealed that AI blocked efficiently the enzymatic activity of digestive amylases of A. siro, and decreased the physiological capacity of mites gut in utilizing a starch component of grain flour. In vivo experiments showed that AI suppressed the population growth of A. siro. The mites were kept for three weeks on experimental diet enriched by AI in concentration range of 0.005 to 0.25%. Population growth of A. siro was negatively correlated with the content of AI in the treated diet with a half-population dose of 0.125%. The suppressive effect of AIs on stored-product mites is discussed in the context of their potential application in GMO crops 相似文献
19.
Bimal Kumar Ghimire Eun Soo Seong Jung Dae Lim Kweon Heo Myong Jo Kim Ill-Min Chung John A. Juvik Chang Yeon Yu 《Plant Cell, Tissue and Organ Culture》2008,95(3):265-274
Efficient transformation of leaf disc-derived callus of Codonopsis lanceolata was obtained using Agrobacterium tumefaciens strain LBA4404 harboring a binary vector, pYBI121, that carries the neomycin phosphotransferase (npt II) gene as a selectable marker. The green shoots recovered from agroinfected explants on selection medium (containing 0.1 mg/l
α-naphthaleneacetic acid (NAA), 1 mg/l 6-benzylaminopurine (BAP), 100 mg/l kanamycin, and 250 mg/l cefotaxime) were rooted
on Murashige and Skoog (MS) medium supplemented with 2 mg/l IBA and 10 mg/l kanamycin. To optimize the transformation conditions,
several factors were assessed, including the co-cultivation period, the duration of pre- and post-culture in darkness and
light, the kanamycin concentration, and the Agrobacterium densities. We produced transgenic Codonopsis lanceolata overexpressing γ-tocopherol methyltransferase (γ-TMT) by this protocol. Moreover, the α-tocopherol content of the plants was enhanced by the overexpression of this gene.
Bimal Kumar Ghimire and Eun Soo Seong contributed equally to this work. 相似文献
20.
Root segments from seedlings of Panax ginseng produced adventitious roots directly when cultured on 1/2 MS solid medium lacking NH4NO3 and containing 3.0 mg l−1 IBA. Using this adventitious root formation, we developed rapid and efficient transgenic root formation directly from adventitious
root segments in P. ginseng. Root segments were co-cultivated with Agrobacterium tumefaciens (GV3101) caring β-glucuronidase (GUS) gene. Putative transgenic adventitious roots were formed directly from root segments on medium with 400 mg l−1 cefotaxime and 50 mg l−1 kanamycin. Kanamycin resistant adventitious roots were selected and proliferated as individual lines by subculturing on medium
with 300 mg l−1 cefotaxime and 50 mg l−1 kanamycin at two weeks subculture interval. Frequency of transient and stable expression of GUS gene was enhanced by acetosyringon (50 mg l−1) treatment. Integration of transgene into the plants was confirmed by the X-gluc reaction, PCR and Southern analysis. Production
of transgenic plants was achieved via somatic embryogenesis from the embryogenic callus derived from independent lines of
adventitious roots. The protocol for rapid induction of transgenic adventitious roots directly from adventitious roots can
be applied for a new Agrobacterium tumefaciens-mediated genetic transformation protocol in P. ginseng. 相似文献