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1.
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2.
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
3.
Sahotra Sarkar 《Journal of genetics》2017,96(5):753-763
This paper argues that Haldane’s The causes of evolution was the most important founding document in the emergence of the received view of evolutionary theory which is typically referred to as the Modern Synthesis. Whether or not this historical development is characterized as a synthesis (which remains controversial), this paper argues the most important component of the emergence of the received view consisted of showing how the formal rules of Mendelian inheritance are based on (or emerge from) the material basis of heredity established by classical genetics primarily through the experimental work on Drosophila genetics of the Morgan school in the 1910s and 1920s. This is one of the most important achievements of Haldane’s book. Thus this paper rejects both (i) the view that the synthesis was a unification of biometry and Mendelism and (ii) the claim that it arose from work primarily done in the late 1930s and 1940s by naturalists rather than theoretical population and classical experimental geneticists. 相似文献
4.
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
5.
Parkinson’s disease (PD) typically appears in late middle-aged and in elderly persons progressing over a period of several
years. The characteristic pathological features of PD patients include defective motor function and cognitive function affecting
the quality of life of PD patients. Oxidative stress is considered to a play a central role along with various other factors
in the pathogenesis of PD and the incidence and prevalence of the disease is incessantly increasing worldwide. The objective
of the current study was to assess mRNA expressional changes of AQP4, TH and PBP in blood samples of control and patients with PD. The study included 30 healthy controls and 90 PD patients subjected to
treatment through the entire period of the study. RNA isolation was carried out using blood samples of the subjects recruited
in the study and used for RT-PCR analysis of AQP4, TH as well as PBP. The mRNA expressions of AQP4 and TH were found to be reduced whereas that of PBP was found to be elevated when compared with those of healthy control samples. The statistically analysed data were presented which could be helpful for appreciation of PD pathology reflecting in the
blood samples of PD population. 相似文献
6.
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
7.
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
8.
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
9.
K. Škrlep M. Bergant G. M. De Winter B. Bohanec J. Žel R. Verpoorte F. Van Iren M. Camloh 《Biologia Plantarum》2008,52(2):329-333
Different lines of cell suspension cultures of Taxus × media Rehd. and Taxus floridana Nutt. were cryopreserved with a two-step freezing method using a simple and inexpensive freezing container instead of a programmable
freezer. Four to seven days old suspension cell cultures were precultured in growth medium supplemented with 0.5 M mannitol
for 2 d. The medium was then replaced with cryoprotectant solution (1 M sucrose, 0.5 M glycerol and 0.5 M dimethylsulfoxide)
and the cells incubated on ice for 1 h. Before being plunged into liquid nitrogen, cells were frozen with a cooling rate of
approximately −1 °C per min to −80 °C. The highest post-thaw cell viability was 90 %. The recovery was line dependent. The
cryopreservation procedure did not alter the nuclear DNA content of the cell lines. The results indicate that cryopreservation
of Taxus cell suspension cultures using inexpensive freezing container is possible. 相似文献
10.
We examined the stomach contents of cookie-cutter sharks, Isistius brasiliensis, collected by drift-net surveys in the western North Pacific in the early summer. The stomachs contained fresh flesh plugs and cephalopod beaks. Approximately half of the flesh plugs were identified as Bryde’s whale, Balaenoptera brydei, based on genetic analysis, and several of the lower beaks were identified as boreal clubhook squid, Onychoteuthis borealijaponica. The range of estimated dorsal mantle lengths for the squids was 60–172 mm. These results are evidence of predation by of cookie-cutter sharks on cetaceans and of an overlap in the vertical distribution of both species. 相似文献
11.
12.
M. Zapater M. Catterou B. Mary M. Ollier L. Fingar E. Mignot F. Ferchaud L. Strullu F. Dubois M. Brancourt-Hulmel 《Bioenergy Research》2017,10(1):115-128
The sustainable development of miscanthus as a bioenergy feedstock requires optimizing its fertilizer inputs and, therefore, determining its nitrogen (N) requirements. The ‘critical nitrogen dilution curve’ is a powerful tool to characterize such N requirements; it relates the N concentration ([N]) in aboveground organs to their biomass, defining two domains depending on whether the N factor limits biomass growth or not. We aimed to develop such a tool in miscanthus. Using a rhizome N depletion strategy with green cutting pre-treatment over several years before the start of the experiment, we grew, in 2014, two cultivated species, Miscanthus × giganteus (M×g) and Miscanthus sinensis (Msin), at four fertilizer levels (0, 80, 160 and 240 kg N ha?1). We found a strong nitrogen fertilization effect. The shoot [N] decreased as the aboveground biomass increased in both species and in all of the treatments. [N] was strongly correlated with leaf/stem biomass ratio. The N treatments enabled the identification of the observed critical points, i.e. points with the maximum biomass (W) and the lowest [N], on each measurement date. These points could be fitted to the following critical dilution curve that was common between M×g and Msin: N concentration (Nc) (critical [N], g N kg?1) = 27.0 W ?0.48 when W > 1 t ha?1 and Nc = 27.0 when W ≤ 1. This curve was validated by literature data, separated into N-limited or not-limited conditions. The similarity of the curves between the two species was due to compensation between leaf/stem biomass ratio and [N] in the stems. This curve is helpful to diagnose the crop N status and define the optimal fertilizer requirements of miscanthus crops. 相似文献
13.
L. Gigliarelli L. Lucentini A. Palomba G. Sgaravizzi H. Lancioni L. Lanfaloni P. Willenz E. Gaino F. Panara 《Hydrobiologia》2008,605(1):265-269
The two freshwater sponges Ephydatia fluviatilis and Ephydatia mülleri belong to the widespread Spongillidae family. Their morphological tracts are very similar and can be distinguished mainly
on the basis of their gemmuloscleres. However, when gemmules are absent it is essential to have an unambiguous species attribution
for a population genetic study based on fresh tissues and historical collections. This article reports a simple Polymerase
Chain Reaction-Restriction Fragment Length Polymorphism (PCR-RFLP) analysis, applied to DNA extracted from both gemmules and
fresh tissues in order to discriminate between the two congeneric E. fluviatilis and E. mülleri. Such a biomolecular method is based on the discriminative enzymes’ digestion of each of the three amplified fragments 5.8S-ITS2-28S,
D3 domain of the 28S subunit and COI. Two restriction enzymes were tested for a 620–642 bp fragment of 5.8S-ITS2-28S and for
a 342 bp fragment of the D3 domain of the 28S, one restriction enzyme was tested for a 681 bp fragment codifying for COI.
Obtained digestion patterns were diagnostic for each of the two species, providing a relatively simple, fast and cheap method
for species attribution compared to sequencing.
Handling editor: C. Sturmbauer 相似文献
14.
Susanne Schlüter Charles M. A. P. Franz Frank Gesellchen Oliver Bertinetti Friedrich W. Herberg Friedrich R. J. Schmidt 《Current microbiology》2009,59(2):206-211
An Enterococcus faecalis mutant strain with a reduced ability for biofilm formation and primary attachment when compared to the high biofilm-forming
wild-type strain was characterized by molecular biological and proteomic approaches. A point mutation in the srt-1 gene, which encodes a sortase-type enzyme and is part of the recently described bee (biofilm enhancer in Enterococcus) gene cluster, could be identified in the mutant strain. The Srt-1 deficiency resulted in a loss of the Bee-2 protein within
a high molecular weight complex in cell surface protein extracts, as determined by mass spectrometry. These findings strongly
suggest a specific linkage of Bee-2 to Bee-1 and Bee-3 within a complex by Srt-1. Furthermore, the identification of specific
pilin motifs conserved in surface proteins of gram-positive bacteria indicated a possible involvement of the bee genes in the formation of pili structures, and may thus play a role in enhancing biofilm formation in Enterococcus faecalis. 相似文献
15.
C. violaceum appeared as important bacterium in different applications and mainly these aspects are related to the production of violacein.
This review discusses the last reports on biosynthetic pathways, production, genetic aspects, biological activities, pathological
effects, antipathogenic screening through quorum sensing, environmental effects and the products of C. violaceum with industrial interest. An important discussion is on biological applications in medicine and as industrial products such
as textile and in cosmetics. 相似文献
16.
17.
Jörg Maletz 《Pal?ontologische Zeitschrift》2010,84(4):501-522
Graptolites from the Jaeger collection at the Museum für Naturkunde (Berlin, Germany) provide important information on structural
details of Silurian (Wenlock–Ludlow) retiolitids as well as for the biostratigraphic and biogeographic distribution of these
magnificent graptolites. Species of the genera Cometograptus, Spinograptus and Plectograptus are described from isolated glacial boulder material, collected in northern Germany and from shale specimens found in the
Lower Graptolite Shale of Thuringia. The biostratigraphic placement of material derived from glacial erratic boulders, however,
is far from being precise. The fauna associated with the neotype of Plectograptus macilentus in the ‘Unterer Graptolithenschiefer’ of Thuringia is discussed and illustrated. Cometograptus alfeisenacki from the Cyrtograptus lundgreni Biozone is recognized as a new species. The genus is discovered for the first time in North German glacial erratic boulders. 相似文献
18.
The reactions of isolates of Phytophthora cactorum, P. nicotianae and P. × pelgrandis to metalaxyl, mancozeb, dimethomorph, streptomycin and chloramphenicol were tested to obtain information about the variability of resistance in these pathogens. Distinct genetic groups showed significant differences in resistance to all tested substances except streptomycin. In response to streptomycin, the growth inhibition rates of distinct groups did not differ significantly. The most remarkable differences were detected in the reactions to chloramphenicol and metalaxyl. Discriminant analysis evaluating the effect of all substances confirmed the differences among the groups, which are in agreement with the differences revealed by earlier DNA analyses. 相似文献
19.
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
20.
In Escherichia coli cellular levels of pppGpp and ppGpp, collectively called (p)ppGpp, are maintained by the products of two genes, relA and spoT. Like E. coli, Vibrio cholerae also possesses relA and spoT genes. Here we show that similar to E. coli, V. cholerae ΔrelA cells can accumulate (p)ppGpp upon carbon starvation but not under amino acid starved condition. Although like in E. coli, the spoT gene function was found to be essential in V. cholerae
relA
+ background, but unlike E. coli, several V. cholerae ΔrelA ΔspoT mutants constructed in this study accumulated (p)ppGpp under glucose starvation. The results suggest a cryptic source of
(p)ppGpp synthesis in V. cholerae, which is induced upon glucose starvation. Again, unlike E. coli ΔrelA ΔspoT mutant (ppGpp0 strain), the V. cholerae ΔrelA ΔspoT mutants showed certain unusual phenotypes, which are (a) resistance towards 3-amino-1,2,4-triazole (AT); (b) growth in nutrient
poor M9 minimal medium; (c) ability to stringently regulate cellular rRNA accumulation under glucose starvation and (d) initial
growth defect in nutrient rich medium. Since these phenotypes of ΔrelA ΔspoT mutants could be reverted back to ΔrelA phenotypes by providing SpoT in trans, it appears that the spoT gene function is crucial in V. cholerae.
Part of this work was presented at the International Symposium on Chemical Biology, Kolkata, India, 7–9 March 2007. 相似文献