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1.
Background
Aeromonas spp. have been regarded as "emerging pathogens". Aeromonads possess multifactorial virulence and the production of many of these virulence determinants is associated with high cell density, a phenomenon that might be regulated by quorum sensing. However, only two species of the genus are reported to possess the luxRI quorum sensing gene homologs. The purpose of this study was to investigate if the luxRI homologs are universally present in the Aeromonas strains collected from various culture collections, clinical laboratories and field studies. 相似文献2.
Débora Souza Collares Maia Castelo-Branco Aline Lobão da Silva Frederico Ozanan Barros Monteiro Glaucia Morgana de Melo Guedes Jamille Alencar Sales Jonathas Sales de Oliveira José Erisvaldo Maia Junior Stefânia Araújo Miranda José Júlio Costa Sidrim Lucas Pereira de Alencar Raimunda Sâmia Nogueira Brilhante Rossana de Aguiar Cordeiro Tereza de Jesus Pinheiro Gomes Bandeira Waldemiro de Aquino Pereira Neto Marcos Fábio Gadelha Rocha 《Antonie van Leeuwenhoek》2017,110(1):33-43
The present study aimed at evaluating the role of captive scarlet ibises (Eudocimus ruber) and their environment as reservoirs of Aeromonas spp. and Plesiomonas spp., and analyzing the in vitro antimicrobial susceptibility and virulence of the recovered bacterial isolates. Thus, non-lactose and weak-lactose fermenting, oxidase positive Gram-negative bacilli were recovered from cloacal samples (n = 30) of scarlet ibises kept in a conservational facility and from water samples (n = 30) from their environment. Then, the antimicrobial susceptibility, hemolytic activity and biofilm production of the recovered Aeromonas spp. and Plesiomonas shigelloides strains were assessed. In addition, the virulence-associated genes of Aeromonas spp. were detected. Ten Aeromonas veronii bv. sobria, 2 Aeromonas hydrophila complex and 10 P. shigelloides were recovered. Intermediate susceptibility to piperacillin-tazobactam and cefepime was observed in 2 Aeromonas spp. and 1 P. shigelloides, respectively, and resistance to gentamicin was observed in 4 P. shigelloides. The automated susceptibility analysis revealed resistance to piperacillin-tazobactam and meropenem among Aeromonas spp. and intermediate susceptibility to gentamicin among P. shigelloides. All Aeromonas isolates presented hemolytic activity, while 3 P. shigelloides were non-hemolytic. All Aeromonas spp. and 3/10 P. shigelloides were biofilm-producers, at 28 °C, while 10 Aeromonas spp. and 6/10 P. shigelloides produced biofilms, at 37 °C. The most prevalent virulence genes of Aeromonas spp. were asa1 and ascV. Scarlet ibises and their environment harbour potentially pathogenic bacteria, thus requiring monitoring and measures to prevent contamination of humans and other animals. 相似文献
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4.
The prevalence of potential virulence markers was determined among the population of Polish Campylobacter jejuni and Campylobacter coli isolates from children, chickens, pigs and dogs. The presence of the flaA, flaB, cdtA, cdtB, cdtC, cdtABC, virB11, and cj0588 genes among 74 C. jejuni and 15 C. coli isolates was detected by PCR. High prevalence of five different putative virulence and toxin genes (flaA, cdtA, cdtB, cdtC, and cj0588) was found among isolates obtained from children, chickens and dogs. The occurrence of these genes among isolates obtained
from pigs was significantly different than for strains isolated from other sources. Two methods for genotyping Campylobacter spp. strains were applied — flaA-typing, and ADSRRS-fingerprinting method, which was used for the first time for Campylobacter spp. strains. Similarity of the genetic profiles was demonstrated in strains isolated from chickens and dogs, and in isolates
from chickens and children. Strains isolated from pigs, both C. jejuni as well as C. coli, did not group with isolates from other sources. 相似文献
5.
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
6.
Attacin, a 20 kDa antibacterial peptide, plays an important role in immunity. To understand this gene better, gene cloning,
expression and biological activity detection of Attacin A was carried out in present study. The full-length open reading frame
(ORF) coding for Attacin A gene was generated using RT-PCR which takes total RNA extracted from Drosophila as the template. The gene was inserted directionally into the prokaryotic expression vector pET-32a (+). The resulting recombinant
plasmid was transformed into E. coli
Rosetta. SDS–PAGE was carried out to detect the expression product which was induced by IPTG. The antimicrobial activity and hemolysis
activity were tested in vitro after purification. Agarose gel electrophoresis indicated that the complete ORF of Attacin A
gene has been cloned successfully from Drosophila stimulated by E. coli which includes 666 bp and encodes 221 AA. The gene encoding mature Attacin A protein was amplified by PCR from the recombinant
plasmid containing Attacin A, which includes 570 bp in all. SDS–PAGE analysis demonstrated that the fusion protein expressed
was approximately 39.2 kDa. Biological activities detection showed that this peptide exhibited certain antibacterial activity
to several G− bacteria, as well as minor hemolysis activity for porcine red blood cells. In conclusion, Attacin A gene was
cloned and expressed successfully. It was the basis for further study of Attacin. 相似文献
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8.
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
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10.
WonKyung Kang 《中国病毒学》2009,24(4):315-322
Viruses including baculoviruses are obligatory parasites, as their genomes do not encode all the proteins required for replication.
Therefore, viruses have evolved to exploit the behavior and the physiology of their hosts and often coevolved with their hosts
over millions of years. Recent comparative analyses of complete genome sequences of baculoviruses revealed the patterns of
gene acquisitions and losses that have occurred during baculovirus evolution. In addition, knowledge of virus genes has also
provided understanding of the mechanism of baculovirus infection including replication, species-specific virulence and host
range. The Bm8 gene of Bombyx mori nucleopolyhedrovirus (NPV) and its homologues are found only in group I NPV genomes. The Autographa californica NPV Ac16 gene is a homologue of Bm8 and, encodes a viral structural protein. It has been shown that Bm8/Ac16 interacts with
baculoviral and cellular proteins. Bm8/Ac16 interacts with baculoviral IE1 that is facilitated by coiled coil domains, and
the interaction with IE1 is important for Bm8 function. Ac16 also forms a complex with viral FP25 and cellular actin and associates
with membranes via palmitoylation. These data suggested that this gene family encodes a multifunctional protein that accomplishes
specific needs of group I NPVs.
相似文献
11.
Zilong Wang Xingfu Zha Ningjia He Zhonghuai Xiang Qingyou Xia 《Molecular biology reports》2010,37(5):2525-2531
RBP1 is an important splicing factor involved in alternative splicing of the pre-mRNA of Drosophila sex-determining gene dsx. In this work, the Bombyx mori homologue of the rbp1 gene, Bmrbp1, was cloned. The pre-mRNA of Bmrbp1 gene is alternatively spliced to produce four mature mRNAs, named Bmrbp1-PA, Bmrbp1-PB, Bmrbp1-PC and Bmrbp1-PD, with nucleotide lengths of 799 nt, 1,316 nt, 894 nt and 724 nt, coding for 142 aa, 159 aa, 91 aa and 117 aa, respectively.
BmRBP1-PA and BmRBP1-PD contain a N terminal RNA recognization motif (RRM) and a C terminal arginine/serine-rich domain, while
BmRBP1-PB and BmRBP1-PC only share a RRM. Amino acid sequence alignments showed that BmRBP1 is conserved with its homologues
in other insects and with other SR family proteins. The RT-PCR showed that Bmrbp1-PA was strongly expressed in all examined tissues and development stages, but Bmrbp1-PB was weakly expressed in these tissues and stages. The expression of both Bmrbp1-PA and Bmrbp1-PB showed no obvious sex difference. While the Bmrbp1-PC and Bmrbp1-PD were beyond detection by RT-PCR very likely due to their tissue/stage specificity. These results suggested that Bmrbp1 should be a member of SR family splicing factors, whether it is involved in the sex-specific splicing of Bmdsx pre-mRNA needs further research. 相似文献
12.
Lee JH Moon YH Kim N Kim YM Kang HK Jung JY Abada E Kang SS Kim D 《Biotechnology letters》2008,30(4):749-754
The gene encoding sucrose phosphorylase (742sp) in Leuconostoc mesenteroides NRRL B-742 was cloned and expressed in Escherichia coli. The nucleotide sequence of the transformed 742sp comprised an ORF of 1,458 bp giving a protein with calculated molecular mass of 55.3 kDa. 742SPase contains a C-terminal amino acid sequence that is significantly different from those of other Leu. mesenteroides SPases. The purified 742SPase had a specific activity of 1.8 U/mg with a K
m of 3 mM with sucrose as a substrate; optimum activity was at 37°C and pH 6.7. The purified 742SPase transferred the glucosyl
moiety of sucrose to cytosine monophosphate (CMP).
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
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14.
Studying Pneumocystis has proven to be a challenge from the perspective of propagating a significant amount of the pathogen in a facile manner.
The study of several fungal pathogens has been aided by the use of invertebrate model hosts. Our efforts to infect the invertebrate
larvae Galleria
mellonella with Pneumocystis proved futile since P. murina neither caused disease nor was able to proliferate within G. mellonella. It did, however, show that the pathogen could be rapidly cleared from the host. 相似文献
15.
S. A. Kopyl N. V. Dorogova E. M. Akhmametyeva L. V. Omelyanchuk L. -S. Chang 《Russian Journal of Genetics》2010,46(3):276-282
The protein Merlin is involved in the regulation of cell proliferation and differentiation in the eyes and wings of Drosophila and is a homolog of the human protein encoded by the Neurofibromatosis 2 (NF2) gene whose mutations cause auricular nerve tumors. Recent studies show that Merlin and Expanded cooperatively regulate the
recycling of membrane receptors, such as the epidermal growth factor receptor (EGFR). By performing a search for potential
genetic interactions between Merlin (Mer) and the genes important for vesicular trafficking, we found that ectopic expression in the wing pouch of the clathrin adapter
protein Lap involved in clathrin-mediated receptor endocytosis resulted in the formation of extra vein materials. On the one
hand, coexpression of wild-type Merlin and lap in the wing pouch restored normal venation, while overexpression of a dominant-negative mutant Mer
DBB
together with lap enhanced ectopic vein formation. Using various constructs with Merlin truncated copies, we showed the C-terminal portion
of the Merlin protein to be responsible for the Merlin-lap genetic interaction. Furthermore, we showed that the Merlin and Lap proteins colocalized at the cortex of the wing imaginal
disc cells. 相似文献
16.
Yan F Peng J Lu Y Lin L Zheng H Chen H Chen J Adams MJ 《Molecular biology reports》2009,36(6):1283-1289
Dicer-like proteins (DCLs) are involved in small RNA-mediated development and viral defense in plants. In model plants, at
least four DCLs have been found and a number of studies have helped to understand their function. However, the function of
the Dicer or DCLs in other plants is still unclear. Here, we report the full-length cDNA sequence of Brassica rapa ssp. chinensis DCL2 (BrDCL2) gene, which contains a 4,179 bp open reading frame (ORF) encoding a protein of 1,392 amino acids. At the 3′ end of BrDCL2, clones with three different lengths of 3′ untranslated region were found. An alternative splice variant of BrDCL2, BrDCL2sv, in which one intron was retained between exon9 and exon10, was also cloned. Because of a change in the coding sequence resulting
in a premature terminal codon, BrDCL2sv was expected to translate a short peptide containing the whole DEXHc domain. 相似文献
17.
Toriba T Harada K Takamura A Nakamura H Ichikawa H Suzaki T Hirano HY 《Molecular genetics and genomics : MGG》2007,277(5):457-468
Members of the YABBY gene family have a general role that promotes abaxial cell fate in a model eudicot, Arabidopsis thaliana. To understand the function of YABBY genes in monocots, we have isolated all YABBY genes in Oryza sativa (rice), and revealed the spatial and temporal expression pattern of one of these genes, OsYABBY1. In rice, eight YABBY genes constitute a small gene family and are classified into four groups according to sequence similarity, exon-intron structure, and organ-specific expression patterns. OsYABBY1 shows unique spatial expression patterns that have not previously been reported for other YABBY genes, so far. OsYABBY1 is expressed in putative precursor cells of both the mestome sheath in the large vascular bundle and the abaxial sclerenchyma in the leaves. In the flower, OsYABBY1 is specifically expressed in the palea and lemma from their inception, and is confined to several cell layers of these organs in the later developmental stages. The OsYABBY1-expressing domains are closely associated with cells that subsequently differentiate into sclerenchymatous cells. These findings suggest that the function of OsYABBY1 is involved in regulating the differentiation of a few specific cell types and is unrelated to polar regulation of lateral organ development. 相似文献
18.
A genetic transformation system has been developed for callus cells of Crataegus
aronia using Agrobacterium
tumefaciens. Callus culture was established from internodal stem segments incubated on Murashige and Skoog (MS) medium supplemented with
5 mg l−1 Indole-3-butyric acid (IBA) and 0.5 mg l−1 6-benzyladenine (BA). In order to optimize the callus culture system with respect to callus growth and coloration, different
types and concentrations of plant growth regulators were tested. Results indicated that the best average fresh weight of red
colored callus was obtained on MS medium supplemented with 2 mg l−1 2,4-dichlorophenoxyacetic acid (2,4-D) and 1.5 mg l−1 kinetin (Kin) (callus maintenance medium). Callus cells were co-cultivated with Agrobacterium harboring the binary plasmid pCAMBIA1302 carrying the mgfp5 and hygromycin phosphotransferase (hptII) genes conferring green fluorescent protein (GFP) activity and hygromycin resistance, respectively. Putative transgenic calli
were obtained 4 weeks after incubation of the co-cultivated explants onto maintenance medium supplemented with 50 mg l−1 hygromycin. Molecular analysis confirmed the integration of the transgenes in transformed callus. To our knowledge, this
is the first time to report an Agrobacterium-mediated transformation system in Crataegus
aronia. 相似文献
19.
Inger-Marie E. Vilcins Julie M. Old Elizabeth Deane 《Experimental & applied acarology》2009,49(3):229-242
Three Australian native animal species yielded 60 samples composed of three indigenous ticks. Hosts included twelve koalas,
two echidnas and one wombat from Victoria, and ticks were of the species Ixodes tasmani (n = 42), Bothriocroton concolor (n = 8) and B. auruginans (n = 10), respectively. PCR screening and sequencing detected a species of Coxiella, sharing closest sequence identity to C. burnetii (>98%), in all B. auruginans, as well as a species of Rickettsia, matching closest to R. massiliae, in 70% of the same samples. A genotype sharing closest similarity to Rickettsia bellii (>99%) was identified in three female B. concolor collected from one of the echidnas. Three samples of I. tasmani, taken from three koalas, yielded different genotypes of Rickettsiella. These results represent the first detection of the three genera in each tick species and identify a high level of previously
undetected bacterial diversity in Australian ticks. 相似文献
20.
Previous work from our laboratory has shown that most of Bacillus thuringiensis strains possess the ability to produce melanin in the presence of l-tyrosine at elevated temperatures (42 °C). Furthermore, it was shown that the melanin produced by B. thuringiensis was synthesized by the action of tyrosinase, which catalyzed the conversion of l-tyrosine, via l-DOPA, to melanin. In this study, the tyrosinase-encoding gene (mel) from B. thuringiensis 4D11 was cloned using PCR techniques and expressed in Escherichia coli DH5 . A DNA fragment with 1179 bp which contained the intact mel gene in the recombinant plasmid pGEM1179 imparted the ability to synthesize melanin to the E. coli recipient strain. The nucleotide sequence of this DNA fragment revealed an open reading frame of 744 bp, encoding a protein of 248 amino acids. The novel mel gene from B.thuringiensis expressed in E. coli DH5 conferred UV protection on the recipient strain. 相似文献