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941.
Iain Darbyshire 《Kew Bulletin》2008,63(2):261-268
Summary Three new species are described in Barleria L. sect. Stellatohirta M. Balkwill from tropical Africa: B. aristata from south-central Tanzania, B. aenea from south-western Tanzania and northeast Zambia, and B. purpureotincta from south-western Zambia. Their affinities and conservation status are discussed. 相似文献
942.
Neuropeptides are a diverse widespread class of signaling substances in the nervous system. As a basis for the analysis of peptidergic neurotransmission in the insect olfactory system, we have studied the distribution of neuropeptides in the antennal lobe of the moth Heliothis virescens. Immunocytochemical experiments with antisera recognizing A-type allatostatins (AST-As), Manduca sexta allatotropin (Mas-AT), FMRFamide-related peptides (FaRPs), and tachykinin-related peptides (TKRPs) have shown that members of all four peptide families are present in local interneurons of the antennal lobe. Whereas antisera against AST-As, Mas-AT, and FaRPs give similar staining patterns characterized by dense meshworks of processes confined to the core of all antennal-lobe glomeruli, TKRPs are present only in neurons with blebby processes distributed throughout each glomerulus. In addition to local neurons, a pair of centrifugal neurons with cell bodies in the lateral subesophageal ganglion, arborizations in the antennal lobe, and projections in the inner antenno-cerebral tracts exhibits tachykinin immunostaining. Double-label immunofluorescence has detected the co-localization of AST-As, Mas-AT, and FaRPs in certain local interneurons, whereas TKRPs occurs in a distinct population. MALDI-TOF mass spectrometry has revealed nearly 50 mass peaks in the antennal lobe. Seven of these masses (four AST-As, two N-terminally extended FLRFamides, and Mas-AT) match known moth neuropeptides. The data thus show that local interneurons of the moth antennal lobe are highly differentiated with respect to their neuropeptide content. The antennal lobe therefore represents an ideal preparation for the future analysis of peptide signaling in insect brain. 相似文献
943.
Immunotherapy with Bacillus Calmette–Guérin (BCG)—an attenuated strain of Mycobacterium bovis (M. bovis) used for anti tuberculosis immunization—is a clinically established procedure for the treatment of superficial bladder cancer.
However, the mode of action has not yet been fully elucidated, despite much extensive biological experience. The purpose of
this paper is to develop a first mathematical model that describes tumor-immune interactions in the bladder as a result of
BCG therapy. A mathematical analysis of the ODE model identifies multiple equilibrium points, their stability properties,
and bifurcation points. Intriguing regimes of bistability are identified in which treatment has potential to result in a tumor-free
equilibrium or a full-blown tumor depending only on initial conditions. Attention is given to estimating parameters and validating
the model using published data taken from in vitro, mouse and human studies. The model makes clear that intensity of immunotherapy
must be kept in limited bounds. While small treatment levels may fail to clear the tumor, a treatment that is too large can
lead to an over-stimulated immune system having dangerous side effects for the patient. 相似文献
944.
945.
A novel approach to DNase I-sensitivity analysis was applied to examining genes of the spermatogenic pathway, reflective of
the substantial morphological and genomic changes that occur during this program of differentiation. A new real-time PCR-based
strategy that considers the nuances of response to nuclease treatment was used to assess the nuclease susceptibility through
differentiation. Data analysis was automated with the K-Lab PCR algorithm, facilitating the rapid analysis of multiple samples
while eliminating the subjectivity usually associated with Ct analyses. The utility of this assay and analytical paradigm as applied to nuclease-sensitivity mapping is presented. 相似文献
946.
Phenyllactic acid (PLA) is a novel antimicrobial compound derived from phenylalanine (Phe). Lactobacillus sp. SK007, having high PLA-producing ability, was isolated from Chinese traditional pickles. When 6.1 mM phenylpyruvic acid
(PPA) was used to replace Phe as substrate at the same concentration, PLA production increased 14-fold and the fermentation
time decreased from 72 h to 24 h with growing cells. With resting cells, however, 6.8 mM PLA could be obtained as optimal
yield using the following conditions: 12 mM PPA, 55 mM glucose, pH 7.5, 35°C and 4 h. 相似文献
947.
Natalia Gutierrez C. M. Avila C. Rodriguez-Suarez M. T. Moreno A. M. Torres 《Molecular breeding : new strategies in plant improvement》2007,19(4):305-314
Faba beans are inexpensive, nutrient-dense sources of plant protein, but anti-nutritional factors such as condensed tannins
reduce the biological value of their protein. Two recessive genes, zt-1 and zt-2, control the absence of tannins in faba bean seeds and also determine a white flower character on the plant. However, crosses
between them produce coloured F1 plants with tannins that contaminate the crop. Therefore, it is important to identify the gene present in all tannin-free
cultivars and gene bank accessions to enable breeders to choose appropriate genitors for their crosses. The aim of this study
was the identification of markers linked to zt-1, one of the genes governing free tannin content in faba bean. A segregating F2 population derived from the cross between the coloured flower and high tannin content genotype Vf6 and a zt-1 line was developed and characterized phenotypically. Bulked Segregant Analysis (BSA) was used to identify Random Amplified
Polymorphic DNA (RAPD) markers linked to the zt-1 gene. Four RAPD loci (OPC5551, OPG15600, OPG111171 and OPAF20776) showed polymorphism between the contrasting bulks. The markers were sequenced to develop specific Sequence Characterised
Amplified Regions (SCARs). Amplification of SCC5551 produced a single product which was only observed in the white flowered and zero tannin content genotypes, whereas SCAR
SCG111171only produced a band in F2 plants with coloured flower and high tannin content. SCARs SCC5551 and SCG111171 were tested for their applicability for routine screening in 37 faba bean genotypes differing in flower colour and tannin
content. SCC5551, allowed the prediction of the zt-1 genotypes with a 95% of accuracy, underscoring the potential of this SCAR marker as a cost-effective tool for MAS in large
faba bean breeding populations. 相似文献
948.
Geric Stare B Fouville D Širca S Gallot A Urek G Grenier E 《Journal of molecular evolution》2011,72(2):169-181
While pectate lyases are major parasitism factors in plant-parasitic nematodes, there is little information on the variability
of these genes within species and their utility as pathotype or host range molecular markers. We have analysed polymorphisms
of pectate lyase 2 (pel-2) gene, which degrades the unesterified polygalacturonate (pectate) of the host cell-wall, in the genus Globodera. Molecular variability of the pel-2 gene and the predicted protein was evaluated in populations of G. rostochiensis, G. pallida, G. “mexicana” and G. tabacum. Seventy eight pel-2 sequences were obtained and aligned. Point mutations were observed at 373 positions, 57% of these affect the coding part
of the gene and produce 129 aa replacements. The observed polymorphism does not correlate either to the pathotypes proposed
in potato cyst nematodes (PCN) or the subspecies described in tobacco cyst nematodes. The trees reveal a topology different
from the admitted species topology as G. rostochiensis and G. pallida sequences are more similar to each other than to G. tabacum. Species-specific sites, potentially applicable for identification, and sites distinguishing PCN from tobacco cyst nematodes,
were identified. As both G. rostochiensis and G. pallida display the same host range, but distinct from G. tabacum, which cannot parasitize potato plants, it is tempting to speculate that pel-2 genes polymorphism may be implicated in this adaptation, a view supported by the fact that no active pectate lyase 2 was
found in G. “mexicana”, a close relative of G. pallida that is unable to develop on cultivated potato varieties. 相似文献
949.
Osman A. Gutiérrez Arin F. Robinson Johnie N. Jenkins Jack C. McCarty Martin J. Wubben Franklin E. Callahan Robert L. Nichols 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2011,122(2):271-280
The identification of molecular markers that are closely linked to gene(s) in Gossypium barbadense L. accession GB713 that confer a high level of resistance to reniform nematode (RN), Rotylenchulus reniformis Linford & Oliveira, would be very useful in cotton breeding programs. Our objectives were to determine the inheritance of
RN resistance in the accession GB713, to identify SSR markers linked with RN resistance QTLs, and to map these linked markers
to specific chromosomes. We grew and scored plants for RN reproduction in the P1, P2, F1, F2, BC1P1, and BC1P2 generations from the cross of GB713 × Acala Nem-X. The generation means analysis using the six generations indicated that
one or more genes were involved in the RN resistance of GB713. The interspecific F2 population of 300 plants was genotyped with SSR molecular markers that covered most of the chromosomes of Upland cotton (G. hirsutum L.). Results showed two QTLs on chromosome 21 and one QTL on chromosome 18. One QTL on chromosome 21 was at map position
168.6 (LOD 28.0) flanked by SSR markers, BNL 1551_162 and GH 132_199 at positions 154.2 and 177.3, respectively. A second
QTL on chromosome 21 was at map position 182.7 (LOD 24.6) flanked by SSR markers BNL 4011_155 and BNL 3279_106 at positions
180.6 and 184.5, respectively. Our chromosome 21 map had 61 SSR markers covering 219 cM. One QTL with smaller genetic effects
was localized to chromosome 18 at map position 39.6 (LOD 4.0) and flanked by SSR markers BNL 1721_178 and BNL 569_131 at positions
27.6 and 42.9, respectively. The two QTLs on chromosome 21 had significant additive and dominance effects, which were about
equal for each QTL. The QTL on chromosome 18 showed larger additive than dominance effects. Following the precedent set by
the naming of the G. longicalyx Hutchinson & Lee and G. aridum [(Rose & Standley) Skovsted] sources of resistance, we suggest the usage of Ren
barb1
and Ren
barb2
to designate these QTLs on chromosome 21 and Ren
barb3
on chromosome 18. 相似文献
950.
Facilitating the recovery of phenotypically normal transgenic lines in clonal crops: a new strategy illustrated in potato 总被引:1,自引:0,他引:1
Barrell PJ Conner AJ 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2011,122(6):1171-1177
Transgenic plants frequently exhibit altered phenotypes, unrelated to transgene expression, which are attributed to tissue
culture-induced variation and/or insertional mutagenesis. Distinguishing between these possibilities has been difficult in
clonal crops such as potato, due to their highly heterozygous background and the resulting inherent phenotypic variability
associated with segregation. This study reports the use of transgene integration as a molecular marker to trace the clonal
origin of single cells in tissue culture. Following transformation, multiple shoots have been regenerated from cell colonies
of potato (Solanum tuberosum L.) and Southern analysis used to confirm their derivation from a single transformed cell. Analysis of phenotypic variation
in field trials has demonstrated marked differences between these multiple regeneration events, the origin of which must have
occurred after T-DNA insertion, and consequently during the tissue culture phase. This result unequivocally demonstrates that
somaclonal variation occurs during tissue culture and independent of transgene insertion. Furthermore, the first shoots recovered
do not necessarily exhibit less somaclonal variation, since later regeneration events can give rise to plants that are more
phenotypically normal. Therefore, when developing transgenic lines for genetic improvement of clonal crops, multiple shoots
should be regenerated and evaluated from each transformation event to facilitate the recovery of phenotypically normal transgenic
lines. 相似文献