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S. Zdravković-Korać D. Ćalić-Dragosavac B. Uzelac D. Janošević S. Budimir B. Vinterhalter D. Vinterhalter 《Plant Cell, Tissue and Organ Culture》2008,94(2):225-231
Somatic embryos of red horse chestnut, derived from cultures maintained through repetitive somatic embryogenesis for a few
years, were subjected to induction of secondary regeneration. The embryos were divided in four classes on the basis of their
size (I-1, II-5, III-10 and IV-30 mm), and sub-cultured on MS media containing 0, 1, 5 or 10 μM kinetin (Kin) or benzyladenine
(BA). The pathway of secondary regeneration, somatic embryogenesis or caulogenesis, depended on the primary somatic embryo
(PSE) stage of development. The embryogenic capacity declined and bud-forming capacity increased with the degree of PSE maturity.
The PSE of the Classes I and II produced only secondary somatic embryos (SSE), the Class III PSE formed both SSE and adventitious
buds, whereas the Class IV PSE developed almost solely adventitious buds. The process of secondary somatic embryogenesis was
most effective in the Class II PSE at 5 μM BA, and the process of adventive organogenesis was most effective in the Class
IV PSE at 10 μM BA. On plant growth regulator (PGR)-free medium, PSE of A. carnea followed the same pattern of adventive regeneration, as those cultured on cytokinin containing media. The cytokinins only
amplified the response, in a certain range of concentrations. BA promoted bud induction at a much higher rate than Kin, while
their embryogenic effect was similar. 相似文献
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Picris
hieracioides var. japonica (Asteraceae), which grows in occasionally disturbed habitats such as riverbanks, is rarely observed under dense vegetation.
We examined the effect of the experience and timing of receiving leaf-transmitted light in gap-detecting seed germination
in this plant. Seeds under unfiltered light, which simulated the light conditions of seeds on the soil surface in a canopy
gap, germinated at a constant temperature of 20°C. However, most seeds in darkness, which simulated the light conditions of
seeds buried in the soil without receiving leaf-transmitted light, germinated under temperature fluctuations of over 4°C.
Seeds in darkness after receiving leaf-transmitted light for 1 week, which simulated the light conditions of seeds buried
in the soil after receiving leaf-transmitted light, germinated under temperature fluctuations of over 8°C. Finally, seeds
under continuous leaf-transmitted light, which simulated the light conditions of seeds on the soil surface below preexisting
vegetation, germinated under temperature fluctuations of over 12°C. Seeds that experience unfiltered light, which suggests
that they are in a gap, should not delay germination. In contrast, seeds that have received leaf-transmitted light should
delay germination until the vegetation above is removed. Seeds exposed to leaf-transmitted light required larger temperature
fluctuations in darkness than did untreated seeds, and seeds under continuous leaf-transmitted light required the largest
temperature fluctuations. The various germination reactions to each gap signal in P.
hieracioides var. japonica seeds allow the more reliable detection of gaps for subsequent seedling establishment. The requirement for gap signals that
created high precision of timing in the germination process results in the germination of this species only in gaps. Therefore,
P.
hieracioides var. japonica is rarely found under dense vegetation. 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
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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
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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
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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
8.
Xianzhong Wang 《Sexual plant reproduction》2007,20(1):45-50
Silene latifolia Poiret is a reliable model system for studying many of the classical problems in biology because little difference in its
physiological response to environmental stimuli has been found between genders. In this experiment, we studied flowering responses
to day length in male and female S. latifolia plants grown at different temperatures. The primary objective was to examine whether flowering in male and female plants was
differentially influenced by day length and temperature. We hypothesized that temperature would interact with day length in
affecting flowering, because both genders have been found to flower in a wide range of day lengths and temperatures. Plants
were grown in environmental chambers at a target temperature of 15/10 or 30/25°C (day/night). Day length was increased by
half-hour intervals until all plants had flowered. Results showed that S. latifolia is a qualitative long-day plant with a critical day length of 11 h. Flowering accelerated with increasing day length until
16.5 h, when all plants flowered. Males and females differed in relative flowering at different day lengths, but to a greater
extent at high than at low temperature. This study demonstrated that flowering of male and female S. latifolia respond differently to day length at different temperatures. A more uniform experimental protocol, especially in controlled
environments, is called for to make this model system a more useful tool in biological studies. 相似文献
9.
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
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The life cycle and developmental stages of Aylax hypecoi (Trotter, 1913, Hymenoptera: Cynipidae: Aylacini) were studied in detail. Aylax hypecoi is known to induce galls in fruits of two Hypecoum species — H. imberbe and H. geslini (Papaveraceae) and the larva develops in host plant fruits. The morphology and development of egg, larva and pupa were investigated, which
has previously not been done. The shape and size of terminal-instar larvae and associated galls are sex-specific. Overwintering
stage, adult emergence and flying periods, and egg productivity were studied also. 相似文献
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Gaye Öngen Gaye Güngör Bahar Kanberoglu 《World journal of microbiology & biotechnology》2007,23(4):519-524
Aspergillus section Nigri strains Aspergillus aculeatus Ege-K 258, A.
foeditus var. pallidus Ege-K156, A. niger Ege-K 4 and A. tubingensis Ege-K 265 were used to treat olive mill wastewater (OMW) in an investigation aimed at exploring their dephenolisation and
decolourisation ability and, consequently, the economic feasibility of using any or all of these strains in a pre-treatment
step in the processing of OMW. Of these strains A. tubingensis Ege-K 265 resulted in an 80% decolourisation of twofold-diluted OMW and a 30% decolourisation of undiluted OMW; in addition,
it was able to remove approximately 30% of all phenolic compounds in both twofold-diluted and undiluted OMW. We conclude that
A. tubingensis Ege-K 265 could be effectively used in the pre-treatment step of a combined aerobic-anaerobic process to solve the environmental
problems caused by OMW in Mediterranean countries. 相似文献
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A. P. Il'chenko O. G. Chernyavskaya T. V. Finogenova 《Applied Biochemistry and Microbiology》2005,41(5):426-432
Results of research into ethanol metabolism in yeast organisms with highly pronounced aerobic metabolism are reviewed. The low activity of NAD-dependent alcohol dehydrogenase (EC 1.1.1.1), observed under conditions of aerobic yeast growth on ethanol, demonstrates that alternative enzyme systems—alcohol oxidase (EC 1.1.3.13), microsomal ethanol-oxidizing system (including cytochrome P-450), and catalase (EC 1.11.1.6)—may be involved in the alcohol oxidation. The role of these systems in alcohol oxidation and the conditions favoring their operation in this processes are analyzed. It is concluded that iron ions are important regulators of ethanol metabolism for the microorganisms of this group. 相似文献
15.
A. P. Kotnova N. N. Karpova M. A. Feoktistova N. V. Lyubomirskaya A. I. Kim Yu. V. Ilyin 《Russian Journal of Genetics》2005,41(1):17-22
A search for noncanonical variants of the gypsy retrotransposon ( MDG4 ) in the genome of the Drosophila melanogaster strain G32 led to the cloning of four copies of the poorly studied 7411-bp gtwin element. Sequence analysis showed that gtwin belongs to a family of endogeneous retroviruses, which are widespread in the Drosophila genome and have recently been termed insect erantiviruses. The gtwin retrotransposon is evolutionarily closest to MDG4, as evident from a good alignment of their nucleotide sequences including ORF2 (the pol gene) and ORF3 (the env gene), as well as the amino acid sequences of their protein products. These regions showed more than 75% homology. The distribution of gtwin was studied in several strains of the genus Drosophila. While strain G32 contained more than 20 copies of the element, ten other D. melanogaster strains carried gtwin in two to six copies per genome. The gtwin element was not detected in D. Hydei or D. Virilis. Comparison of the cloned gtwin sequences with the gtwin sequence available from the D. melanogaster genome database showed that the two variants of the mobile element differ by the presence or absence of a stop codon in the central region of ORF3. Its absence from the gtwin copies cloned from the strain G32 may indicate an association between the functional state of ORF3 and amplification of the element.Translated from Genetika, Vol. 41, No. 1, 2005, pp. 23–29.Original Russian Text Copyright © 2005 by Kotnova, Karpova, Feoktistova, Lyubomirskaya, Kim, Ilyin. 相似文献
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Quantitative trait loci (QTL) detection was carried out for adventitious rooting and associated propagation traits in a second-generation
outbred Corymbia torelliana × Corymbia citriodora subspecies variegata hybrid family (n = 186). The parental species of this cross are divergent in their capacity to develop roots adventitiously on stem cuttings
and their propensity to form lignotubers. For the ten traits studied, there was one or two QTL detected, with some QTL explaining
large amounts of phenotypic variation (e.g. 66% for one QTL for percentage rooting), suggesting that major effects influence
rooting in this cross. Collocation of QTL for many strongly genetically correlated rooting traits to a single region on linkage
group 12 suggested pleiotropy. A three locus model was most parsimonious for linkage group 12, however, as differences in
QTL position and lower genetic correlations suggested separate loci for each of the traits of shoot production and root initiation.
Species differences were thought to be the major source of phenotypic variation for some rooting rate and root quality traits
because of the major QTL effects and up to 59-fold larger homospecific deviations (attributed to species differences) relative
to heterospecific deviations (attributed to standing variation within species) evident at some QTL for these traits. A large
homospecific/heterospecific ratio at major QTL suggested that the gene action evident in one cross may be indicative of gene
action more broadly in hybrids between these species for some traits. 相似文献
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Summary. The paper describes two methods of the synthesis of ethyl (3R,4S)- and (3S,4S)-4-[(benzyloxycarbonyl)amino]-5-[(tert-butyloxycarbonyl)amino]-3-hydroxypentanoates, useful for the syntheses of edeine analogs. Differently N-protected (S)-2,3-diaminopropanoic acid was used as a substrate in both procedures. The absolute configuration of newly generated asymmetric
carbon atoms C-3 in β-hydroxy-γ,δ-diamino products was assigned by means of 1H NMR spectroscopy after their transformation into corresponding piperidin-2-ones.
Received May 24, 2002 Accepted October 10, 2002 Published online December 18, 2002
Acknowledgment The authors are indebted to the Faculty of Chemistry, Technical University of Gdańsk for financial support.
Authors' address: Zbigniew Czajgucki, M. Sc., Department of Pharmaceutical Technology and Biochemistry, Faculty of Chemistry, Technical University
of Gdańsk, 11/12 Narutowicza St., 80-952 Gdańsk, Poland, Fax +48 58 347 11 44, E-mail: zmczaj@wp.pl 相似文献
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Hiroki Saito Qingbo Yuan Yutaka Okumoto Kazuyuki Doi Atsushi Yoshimura Hiromo Inoue Masayoshi Teraishi Takuji Tsukiyama Takatoshi Tanisaka 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2009,119(2):315-323
A recently established rice breeding program in low latitudes aims to develop varieties with extremely long basic vegetative
growth (BVG) periods and weak photoperiod sensitivities. The Taiwanese japonica variety Taichung 65 (T65) harbors a recessive allele ef1 at the Ef1 (Early flowering 1) locus, thereby exhibiting an extremely long BVG period. The previous reported functional allele Ehd1 (Early heading date 1), located on chromosome 10, encodes a B-type response regulator, thereby shortening the BVG period, whereas its nonfunctional
allele ehd1 greatly prolongs the BVG period. A conventional analysis using F2 and F3 populations and a subsequent CAPS analysis based on the amino acid sequences of Ehd1 and ehd1 showed that Ef1 and Ehd1 were at the same locus. The CAPS analysis also indicated that the Taiwanese japonica varieties with extremely long BVG periods all harbor ef1, but that ef1 does not exist among indica and japonica varieties in the low latitudes. Since ef1 has not been found in any japonica varieties outside Taiwan, this allele might have originated in Taiwan. Sequence analysis revealed that the mutant allele
ef1-h, which prolongs the BVG period even more than ef1 does, harbors an mPing insertion in exon 2, which causes the complete loss of gene function. Our results indicate that both ef1 or ef1-h alleles can be used as new gene sources in developing rice varieties with extremely long BVG periods for low latitudes.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献