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951.
Sesbania drummondii (Rydb.) Cory is a source for phytopharmaceuticals. It also hyperaccumulates several toxic heavy metals. Development of an
efficient gene transfer method is an absolute requirement for the genetic improvement of this plant with more desirable traits
due to limitations in conventional breeding methods. A simple protocol was developed for Agrobacterium-mediated stable genetic transformation of Sesbania. Agrobacterium
tumefaciens strain EHA 101 containing the vector pCAMBIA 1305.1 having hptII and GUS plus genes was used for the gene transfer experiments. Evaluation of various parameters was carried out to assess
the transformation frequency by GUS expression analysis. High transformation frequency was achieved by using 7-day-old precultured
cotyledonary node (CN) explants. Further, the presence of acetosyringone (150 μM), infection of explants for 30–45 min and
3 days of cocultivation proved to be critical factors for greatly improving the transformation efficiency. Stable transformation
of S. drummondii was achieved, and putative transgenic shoots were obtained on medium supplemented with hygromycin (25 mg l−1). GUS histochemical analysis of the putative transgenic tissues further confirmed the transformation event. Genomic Southern
blot analysis was performed to verify the presence of transgenes and their stable integration. A transformation frequency
of 4% was achieved for CN explants using this protocol. 相似文献
952.
Fawzeia H. Elmhalli Katinka Pålsson Jan Örberg Thomas G. T. Jaenson 《Experimental & applied acarology》2009,48(3):251-262
The toxicity of para-menthane-3,8-diol (PMD), the main arthropod-repellent compound in the oil of the lemon eucalyptus, Corymbia citriodora, was evaluated against nymphs of Ixodes ricinus using five methods (A–E) of a contact toxicity bioassay. Mortality rates were estimated by recording numbers of dead nymphs
at 30 min intervals during the first 5 h after the start of exposure and at longer intervals thereafter. The mortality rate
increased with increasing concentration of PMD and duration of exposure with a distinct effect after 3.5 h. From the results
obtained by methods A, C and E, the LC50 range was 0.035–0.037 mg PMD/cm2 and the LC95 range was 0.095–0.097 mg PMD/cm2 at 4 h of exposure; the LT50 range was 2.1–2.8 h and the LT95 range was 3.9–4.2 h at 0.1 mg PMD/cm2. To determine the duration of toxic activity of PMD, different concentrations (0.002, 0.01, 0.1 mg PMD/cm2) were tested and mortality was recorded at each concentration after 1 h; thereafter new ticks were tested. This test revealed
that the lethal activity of PMD remained for 24 h but appeared absent after 48 h. The overall results show that PMD is toxic
to nymphs of I. ricinus and may be useful for tick control. 相似文献
953.
Mark L. Mallory Anthony J. Gaston Mark R. Forbes H. Grant Gilchrist 《Polar Biology》2009,32(4):529-538
The northern fulmar (Fulmarus glacialis) is a common seabird of the North Atlantic Ocean, with breeding colonies broadly dispersed between 45°N and 80°N. At higher
latitudes, breeding fulmars experience extensive sea-ice and presumably snow and low temperatures which do not affect fulmars
in the southern part of the breeding range. We studied the relationship between weather and reproductive success of northern
fulmars breeding at two colonies in the Canadian high Arctic. Collectively, hatching success, fledging success, and productivity
(chicks fledged per egg laid) were similar between our study and results from colonies located south of the Arctic. However,
a larger proportion of fulmars at apparently occupied sites (AOS) in high Arctic colonies appeared to forego egg-laying, resulting
in lower proportions of chicks fledged per AOS. Extreme inclement weather was the major factor influencing nesting success,
resulting in pulses of egg or chick loss during or immediately following major storms, although the mechanism of effects appeared
to differ between the two colonies. For Arctic fulmars, the risks of nest failure due to stochastic, deleterious weather events
may be offset by the predictable abundance of food supplies during chick-rearing in Arctic waters. 相似文献
954.
Both uniform persistence and the existence of periodic coexistence state are established for a periodically forced Droop model
on two phytoplankton species competition in a chemostat under some appropriate conditions. Numerical simulations using biological
data are presented as well to illustrate the main result.
Research supported in part by the NSERC of Canada and the MITACS of Canada. 相似文献
955.
Recombinant near-isogenic lines: a resource for the mendelization of heterotic QTL in maize 总被引:1,自引:0,他引:1
Giorgio Pea Paulinesandra Paulstephenraj Maria Angela Canè Maria Luisa Savo Sardaro Pierangelo Landi Michele Morgante Enrico Porceddu Mario Enrico Pè Elisabetta Frascaroli 《Molecular genetics and genomics : MGG》2009,281(4):447-457
Although heterosis is widely exploited in agriculture, a clear understanding of its genetic bases is still elusive. This work
describes the development of maize recombinant near-isogenic lines (NILs) for the mendelization of six heterotic QTL previously
identified based on a maize (Zea mays L.) RIL population. The efficient and inexpensive strategy adopted to generate sets of NILs starting from QTL-specific residual
heterozygous lines (RHLs) is described and validated. In particular, we produced nine pairs of recombinant NILs for all six
QTL starting from RHLs F4:5 originally obtained during the production of the RIL population mentioned above. Whenever possible, two different NIL pairs
were generated for each QTL. The efficiency of this procedure was tested by analyzing two segregating populations for two
of the selected heterotic QTL for plant height, yield per plant and ears per plant. Both additive and dominant effects were
observed, consistently with the presence of the QTL within the introgressed regions. Refinement of QTL detection was consistent
with previous observations in terms of effects and position of the considered QTL. The genetic material developed in this
work represents the starting point for QTL fine mapping aimed at understanding the genetic bases of hybrid vigor in maize.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
956.
957.
Åsa Lankinen 《Journal of genetics》2009,88(2):205-215
Understanding the genetics of a polymorphic trait is important to predict its likely evolution. In Collinsia heterophylla, the upper petal lip colour can be either be white or white with a purple band, while the lower petal lip colour is invariably
purple. Because the corolla is only partly polymorphic, the polymorphism can not have evolved due to a mutation where a pigment
was lost in the entire plant, which is common in other polymorphic species. In a previous study, high frequency of the purple
band was found in populations with darker flowers, indicating possible selection for this trait. In this study, I determined
inheritance of the colour polymorphism using two populations (one with only white morph and other with both morphs). I conducted
experimental crosses within and between floral morphs to determine whether patterns of segregation in offspring conform to
single-gene predictions. Data from F1, F2, F3 and backcross progeny are consistent with a genetic model of one major locus with presence of the band being completely dominant,
as indicated in earlier studies using distantly related populations. A novel finding in this study was that the two morphs
did not show a difference in seed germination frequency or seedling survival. This trait can thus be valuable as a genetic
marker. Even though more thorough ecological data are needed to understand the potential selection pressures on upper petal
lip colour in C. heterophylla, its simple inheritance may indicate the possibility of fast evolutionary response to selective forces acting on this trait. 相似文献
958.
Two experiments were conducted to evaluate the effects of dietary supplementation with Astragalus polysaccharide (APS) on growth performance, apparent ileal digestibilities (AID) of amino acids (AA), and their serum concentrations
in early weaned piglets. In Exp. 1, 60 pigs were weaned at 21 days of age (BW 7.35 ± 0.23 kg) and allocated to three treatments
(20 pigs/treatment), representing supplementing 0.0% (control), 0.02% colistin (antibiotic), or 0.1% APS to a corn- and soybean
meal-based diet. Average daily gain (ADG), average daily feed intake (ADFI), and feed/gain ratio (F/G) were measured weekly.
Blood samples were obtained from five pigs selected randomly from each treatment for the measurement of serum free AA concentrations
on days 7, 14, and 28. In Exp. 2, 12 pigs were weaned at 21 day of age (BW 7.64 ± 0.71 kg), assigned to three treatment groups
as in Exp. 1, and surgically fitted with a simple T-cannula at the terminal ileum. Ileal digesta samples were obtained for
the measurement of AID of AA on days 7, 14 and 28. Dietary APS did not affect ADFI, but enhanced (P < 0.05) ADG by 11 and 4.4%, and improved F/G by 5.6 and 8.4%, respectively, compared with the control and antibiotic groups.
Addition of APS to the diet increased AID and serum concentrations of most nutritionally essential and non-essential AA (including
arginine, proline, glutamate, lysine, methionine, tryptophan, and threonine) on days 14 and 28. Circulating levels of total
AA were affected by the age of pigs and treatment × time interaction. Collectively, these findings indicate that APS may ameliorate
the digestive and absorptive function and regulate AA metabolism to beneficially increase the entry of dietary AA into the
systemic circulation, which provide a mechanism to explain the growth-promoting effect of APS in early weaned piglets. 相似文献
959.
Woong-Ki Min Sunggil Kim Soon-Kee Sung Byung-Dong Kim Sanghyeob Lee 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2009,119(7):1289-1299
Cytoplasmic male sterility (CMS), one of the most important traits in crop breeding, is used for commercial F1-hybrid seed production in peppers (Capsicum annuum L.). A nuclear gene, Restorer-of-fertility (Rf), can induce normal pollen production in CMS plants resulting in fertility. Since the first report of fertility restoration
in peppers, various inheritance modes have been suggested, including the presence of a third haplotype of the locus. The pepper
Rf gene has not been cloned, and calculated genetic distances of linked markers have varied between research groups. A more
precise allelic test and additional genetic mapping are needed to accurately select recombinants for use in marker-assisted
backcrossing (MAB). Therefore, the reliability and application of these markers for allelic selection of the Rf gene was tested. Two different F2 populations, Buja and Tamna, were used for the construction of a linkage map. From these linkage groups, a new closely linked
flanking marker of the Rf gene were identified. Previous allelic testing revealed the existence of a third haplotype, Rfls
7701
, which can function as dominant (Rf) or recessive (rf). In a previous report, Rfls
7701
was considered to be linked to unstable male sterility (MS). However, our results suggest that unstable MS was induced by
a gene residing at another locus rather than by Rfls
7701
haplotype-linked allele. 相似文献
960.
Song-sheng Shi Wei-zhong Yang Ye Chen Jian-ping Chen Xian-kun Tu 《Neurochemical research》2014,39(5):793-799
Our previous studies demonstrated that inflammatory reaction and neuronal apoptosis are the most important pathological mechanisms in ischemia-induced brain damage. Propofol has been shown to attenuate ischemic brain damage via inhibiting neuronal apoptosis. The present study was performed to evaluate the effect of propofol on brain damage and inflammatory reaction in rats of focal cerebral ischemia. Sprague–Dawley rats underwent permanent middle cerebral artery occlusion, then received treatment with propofol (10 or 50 mg/kg) or vehicle after 2 h of ischemia. Neurological deficit scores, cerebral infarct size and morphological characteristic were measured 24 h after cerebral ischemia. The enzymatic activity of myeloperoxidase (MPO) was assessed 24 h after cerebral ischemia. Nuclear factor-kappa B (NF-κB) p65 expression in ischemic rat brain was detected by western blot. Cyclooxygenase-2 (COX-2) expression in ischemic rat brain was determined by immunohistochemistry. ELISA was performed to detect the serum concentration of tumor necrosis factor-α (TNF-α). Neurological deficit scores, cerebral infarct size and MPO activity were significantly reduced by propofol administration. Furthermore, expression of NF-κB, COX-2 and TNF-α were attenuated by propofol administration. Our results demonstrated that propofol (10 and 50 mg/kg) reduces inflammatory reaction and brain damage in focal cerebral ischemia in rats. Propofol exerts neuroprotection against ischemic brain damage, which might be associated with the attenuation of inflammatory reaction and the inhibition of inflammatory genes. 相似文献