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1.
BACTERIAL cells can repair DNA which has been damaged by irradiation with ultraviolet light (UV). A repair process which does not depend on light is known as dark reactivation. Because the cells can repair damaged infecting DNA, as well as their own by the same mechanism the phenomenon has also been called host cell reactivation (HCR). HCR seems to consist of the following reaction steps1: (1) endonucleolytic incision close to the UV photoproduct which most frequently is a pyrimidine dimer; (2) excision of the photoproduct as an oligonucleotide; (3) resynthesis of the removed nucleotide sequence using the opposite strand as a template; and (4) rejoining of the polynucleotide chains. 相似文献
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An experiment was taken up to find out possibilities of manipulating the in vitro flowering in moth bean. Abscisic acid (ABA) and proline both alone and in combination influenced days to flower induction,
number of flowers per plant, number of pods per plant and seeds per pod. Frequency of flowering plants approached 100 % at
1 and 3 μM ABA and 800 μM proline. The range of flowering period (3 to 23.6 d) has also been influenced by various treatments. 相似文献
4.
There are three most important bacterial causative agents of serious infections that could be misused for warfare purposes:
Bacillus anthracis (the causative agent of anthrax) is the most frequently mentioned one; however, Fracisella tularensis (causing tularemia) and Yersinia pestis (the causative agent of plague) are further bacterial agents enlisted by Centers for Disease Control and Prevention into the category A of potential biological weapons. This review intends to summarize basic information about these bacterial
agents. Military aspects of their pathogenesis and the detection techniques suitable for field use are discussed. 相似文献
5.
S. Kumar Sunil Kumar S. P. Negi J. K. Kanwar 《In vitro cellular & developmental biology. Plant》2008,44(6):474-479
Callus cultures derived from leaf segments of chrysanthemum cultivar ‘Snow Ball’ which was susceptible to Septoria obesa were successfully used for in vitro selection for resistance to this pathogenic fungus. Resistant cell lines were selected by culturing callus on growth medium
containing various concentrations of S. obesa filtrate. Resistant calluses obtained after two cycles (30 d each cycle) of selection were used for plant regeneration. About
30% of the plants regenerated from the resistant calluses and 70–80% of the plants raised from cuttings had acquired considerable
resistance against the pathogen in the field. No phenotypic variation was observed in the selected regenerates. 相似文献
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The influence of sugars and growth regulators on shoot and root growth of Dactylorhiza species was studied under in vitro conditions. The seedling development was stimulated with the application of glucose and sucrose at concentration of 10 g
dm−3 each. The improvement of shoot growth rate and shoot length was enhanced by cytokinins N
6-(2-isopentenyl)adenine or N
6-benzyladenine and their combination with auxin indolebutyric acid (IBA). The root growth rate and root length of seedlings
increased in the presence of IBA and α-naphthaleneacetic acid. Individual Dactylorhiza species showed statistically significant differences in shoot and root development depending on sugar and growth regulator
combinations. 相似文献
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R. Ramirez-Malagon I. Aguilar-Ramirez A. Borodanenko L. Perez-Moreno J. L. Barrera-Guerra H. G. Nuñez-Palenius N. Ochoa-Alejo 《In vitro cellular & developmental biology. Plant》2007,43(6):660-665
Mammillaria species are the most numerous within Cactaceae family, and some of them are threatened with extinction as a result of human
activities. In this work, results of in vitro propagation are presented for ten Mammillaria species, testing 20 combinations of indole-3-acetic acid (IAA) and kinetin. Best results on shoot formation were obtained
using kinetin at two levels: 27.9 and 46.5 μM. All IAA levels tested were able to induce de novo shoot formation in M. bocasana, M. densispina, M. hahniana, M. hutchisoniana, M. orcutii, M. pectinifera, M. perbella, M. picta, M. rhodantha, and M. zephyranthoides. Depending on the IAA level tested, four responding groups were observed concerning their highest shoot-formation number.
For all species, the highest average of shoot formation was achieved with 5.7:46.5 or 11.4:46.5 μM IAA/kinetin, yielding 4.8
and 4.7 shoots per explant, respectively, in 60 d. Rooting of regenerated shoots was achieved by leaving the explants in their
shoot-induction medium or transferring them to half-strength MS medium. Hardening of regenerated plants was successfully achieved
by planting them in peat moss substrate after a desiccation treatment at room temperature for 3 d. 相似文献
11.
Aneesh Kumar Nair Naik Dhiraj Dilip Pandit Sagar Subhash 《Journal of Plant Biology》2007,50(3):374-377
High-frequencyin vitro flowering is reported here fromin vitro regenerated shoots ofin vitro-raised seedlings of rare and endemicCeropegia lawii, Ceropegia maccannii, Ceropegia oculata, andCeropegia sahyadrica, as well as the widely distributedCeropegia bulbosa var.bulbosa andCeropegia hirsuta. In our first set of experiments, the MS medium contained 87 mM sucrose and was supplemented with varying concentrations of
BAP (4.4 to 26.6 μM). For the second set of trials, varying concentrations of sucrose (87 to 233 mM) were tested in MS media
containing a constant 4.4 p.M BAP. Sub-cultured apical as well as axillary buds flowered with similar frequencies after 30
d of incubation. For all six species, the highest percentage of flowering shoots was obtained with either 26.6 μM BAP or 175
mM sucrose. Although smaller in size, theirin vitro flowers were morphologically comparable within wVo-derived flowers. Variations among species were noted for the number of flower buds per shoot and the percentage of flower
formation. Because all six species showed similar responses in both experiments, we can suggest that this protocol is applicable
across the wide range ofCeropegia species. 相似文献
12.
O. V. Golovanova V. I. Konenkov A. V. Shevchenko M. V. Smolnikova 《Russian Journal of Genetics》2009,45(8):981-986
Based on population analysis of the DRB1, DQA1, DQB1 and TNFA allele frequency distribution patterns, regional features of immunogenetic structure of the population of West Siberia were
investigated. Statistically significant linkage disequilibrium within the HLA class II region, as well as between the TNFA and DRB1, DQA1, and DQB1 was demonstrated. Population frequency distribution patterns of two- and multilocus haplotypes were examined. 相似文献
13.
New Indicator of Histocompatibility Differences <Emphasis Type="Italic">in vitro</Emphasis> 总被引:8,自引:0,他引:8
THE haemolytic plaque-forming cell (p.f.c.) response to sheep erythrocytes (SRBC) of cultures containing spleen cells from two different strains of mouse may be depressed if the mice differ sufficiently at the H-2 locus1. In our system, however, the usual result is stimulation rather than depression. We present evidence that such stimulation does not result, as has been suggested2,3, from synergism between two cell populations, but from an immune reaction based on histocompatibility differences between them. The system provides a sensitive indicator for detecting and assessing immune reactions between histoincompatible lymphoid cells and mitogenic factors released by such reactions. 相似文献
14.
THE replicon hypothesis put forward by Jacob, Brenner and Cuzin1 postulated two elements involved in initiation of chromosomal replication: (1) a structure on the DNA, termed replicator and (2) a diffusible factor (or factors)—called the initiator—which acts on the replicator to initiate replication. 相似文献
15.
CYCLIC 3′,5′ adenosine monophosphate (cyclic AMP) is a powerful vasodilator1 and it is natural to ask whether it mediates the action of known vasodilator drugs. In this connexion we have studied two potent systemic and coronary vasodilators, diazoxide2 and a dipyridamole derivative, 1,1,-2,7-dimorphocino-6-phenyl-2-pteridinyl-imino di-2-propanol (RE102) (ref. 3). 相似文献
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An in vitro method for propagation of Holarrhena antidysenterica Wall. has been developed using nodal explants from mature trees growing in the field. Irrespective of concentrations and
combinations of growth regulators used, the axillary and terminal buds sprouted and elongated when inoculated on Murashige
and Skoog (MS) medium. The highest numbers of shoots were formed when sprouted shoots were subcultured from MS basal medium
onto MS medium containing 2 mg dm−3 N6-benzyladenine (BA) and 0.5 mg dm−3 α-naphthalene acetic acid (NAA). The shoot number further increased upon subculture on MS medium containing 0.5 mg dm−3 BA. By repeated sub-culturing of shoots derived from nodal axillary buds, a high frequency multiplication rate was established.
The elongated shoots were excised and rooted in auxin free MS basal medium. Ex vitro rooting of in vitro formed shoots was achieved upon dipping the microshoots for 2 min in 2 mg dm−3 of indole-3-butyric acid solution. Successful field establishment and high (80–90 %) survival of plants was observed. 相似文献
17.
To overexpress the chitosanase gene (csn) in F. solani, a vector based on pCAMBIA 1300 was constructed. The csn gene, which is under control of the Aspergillus nidulans
gpdA promoter and A. nidulans trpC terminator, was introduced back into the F. solani genome by Agrobacterium tumefaciens-mediated transformation, and the herbicide-resistance gene bar from Streptomyces hygroscopicus was used as the selection marker. Transformants which showed a significant increase in chitosanase production (~2.1-fold
than control) were obtained. Southern blot analysis indicated that most transformants had a single-copy T-DNA integration. 相似文献
18.
The intron sequence of chloroplast rpS16 and the secondary structure of its pre-mRNA were characterized for the first time in 26 Allium sativum accessions of different ecologo-geographical origins and seven related Allium species. The boundaries and main stem-loop consensus sequences were identified for all six domains of the intron. Polymorphism
was estimated for the total intron and its regions. The structural regions of the rpS16 intron proved to be heterogeneous for mutation rate and spectrum. Mutations were most abundant in domains II and IV, and
transition predominated in domains I, III, V, and VI. In addition to structural elements and motifs typical for group IIB
introns, several Allium-specific micro- and macrostructural mutations were revealed. A 290-bp deletion involving domains III and IV and part of domain
V was observed in A. altaicum, A. fistulosum, and A. schoenoprasum. Several indels and nucleotide substitutions were found to cause a deviation of the pre-mRNA secondary structure from the
consensus model of group II introns. 相似文献
19.
Hiroyoshi Kubo 《Mycoscience》2009,50(5):400-406
Pilobolus crystallinus shows unique photoresponses at various growing stages. cDNAs for putative photoreceptors were cloned from this fungus. Three
genes named pcmada1, pcmada2, and pcmada3 were identified from the PCR fragments, and amplified with degenerated primers for the LOV domain, which is conserved in
many blue-light receptors. Deduced amino acid sequences for PCMADA1, PCMADA2, and PCMADA3 had one light-oxygen-voltage (LOV)-sensing
and two PER-ARNT-SIM (PAS) domains. A zinc finger DNA-binding motif was conserved in the C-terminals of PCMADA1 and PCMADA3.
However, PCMADA2 lacked the zinc finger motif. Expression of pcmada1 was suppressed by blue light whereas that of pcmada3 was promoted by blue-light irradiation. 相似文献
20.
H. L. E. Magariños C. Sahr S. D. C. Selaive M. E. Costa F. E. Figuerola O. A. Pizarro 《Applied Biochemistry and Microbiology》2008,44(3):300-304
The purpose of this study was to determine the inhibitory effects of cranberry juice on pathogenic microorganisms. The microorganisms
analyzed were Escherichia coli from patients with urinary infections, Salmonella spp., Listeria monocytogenes, Pseudomona aeruginosa, and Staphylococcus aureus. The disc method was used to determine the sensitivity of bacteria to cranberry juice (CJ, both concentrated and diluted).
A lawn of 106 cfu/ml was grown on agar surfaces in Petri dishes and on Whatman discs that had been previously saturated with CJ and CJ
: water. 1 : 1 to 1 : 50 juice solutions had been placed on the discs, which were cultured and incubated. The results indicated
that S. aureus was more susceptible to cranberry juice inhibition than the other microorganisms. L. monocytogenes was the most resistant to the inhibitory action of cranberry juice, showing a significant difference from the inhibition
of P. aeruginosa, uropathogenic E. coli, Salmonella spp., and S. aureus. This study also demonstrated that the inhibitory activity of cranberry juice for E. coli took place up to a dilution of 1 : 20.
Published in Russian in Prikladnaya Biokhimiya i Mikrobiologiya, 2008, Vol. 44, No. 3, pp. 333–336.
The text was submitted by the authors in English. 相似文献