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931.
Faheem M Raheel U Riaz MN Kanwal N Javed F us Sahar Sadaf Zaidi N Qadri I 《Molecular biology reports》2011,38(6):3731-3740
More than one third of the world’s population living in tropical and subtropical areas of the world is at risk of dengue infections
and as many as 100 million people are yearly infected. This disease has reemerged during the past 20 years in the form of
an epidemic. Dengue is caused by one of four related serotypes of dengue virus and often leads to severe forms of the disease,
resulting commonly from secondary infections. Dengue virus is a mosquito borne virus, belongs to the family Flaviviridae and consists of a single stranded positive sense RNA genome. Like other RNA viruses it escapes defense mechanisms and neutralization
attempts by mutations, which make it more resistant and adaptable to its environment. Antiviral strategies and vaccine development
is thus impaired and hence to date there is no licensed vaccine available for dengue virus. Here we discuss various efforts
made towards the identification of potential vaccine targets for dengue as well as various strategies employed by research
groups/pharmaceutical companies towards the development of a successful dengue vaccine. 相似文献
932.
Ahmad MS Ashraf M Tabassam Q Hussain M Firdous H 《Biological trace element research》2011,144(1-3):1229-1239
The phytotoxic effects of lead (Pb) on seed germinability, seedling growth, photosynthetic performance, and nutrient accumulation (K(+) and Cu(2+)) in two maize genotypes (EV-1098 and EV-77) treated with varying levels of PbSO(4) (0.01, 0.1, and 1.0 mg L(-1)) were appraised in this study. In the seed germination experiment, lead stress significantly reduced seed germination percentage and index, plumule and radicle lengths as well as fresh and dry weights in both genotypes. In the second experiment, lengths and fresh and dry weights of shoots and roots decreased due to Pb in both genotypes with increase in plant age. Higher Pb levels also decreased photosynthetic rate (A), water use efficiency (A/E), and intrinsic water use efficiency (A/g(s)), but increased transpiration rate (E) and C(i)/C(a) ratio as a result of increase in stomatal conductance (g(s)). The concentrations of K(+) and Cu(2+) decreased in root, stem, and leaves of both genotypes, which could be a direct consequence of multifold increase in Pb concentration in these tissues. Overall, cv. EV-1098 had better Pb tolerance potential than EV-77 because the former genotype showed less reduction in seed germinability parameters, photosynthetic performance, and K(+) and Cu(2+) accumulation in shoot and root under lead stress. 相似文献
933.
Raham Sher Khan Syed Sartaj Alam Iqbal Munir Pejman Azadi Ikuo Nakamura Masahiro Mii 《Plant Cell, Tissue and Organ Culture》2011,106(1):11-20
The presence of marker genes conferring antibiotic or herbicide resistance in transgenic plants has been a controversial issue
and a serious problem for their public acceptance and commercialization. The MAT (multi-auto-transformation) vector system
has been one of the strategies developed to excise the selection marker gene and produce marker-free transgenic plants. In
an attempt to produce transgenic marker-free Petunia hybrida plants resistant to Botrytis cinerea (gray mold), we used the ipt gene as a selectable marker gene and the wasabi defensin (WD) gene, isolated from Wasabia japonica (a Japanese horseradish which has been a potential source of antimicrobial proteins), as a gene of interest. The WD gene was cloned from the binary vector, pEKH-WD, to an ipt-type MAT vector, pMAT21, by gateway cloning technology and transferred to Agrobacterium
tumefaciens strain EHA105. Infected leaf explants of P.
hybrida were cultured on hormone- and antibiotic-free MS medium. Extreme shooty phenotype (ESP)/ipt shoots were produced by the explants infected with the pMAT21-WD. The same antibiotic- and hormone-free MS medium was used in subcultures of the ipt shoots. Ipt shoots subsequently produced morphologically normal shoots. Molecular analyses of genomic DNA from the transgenic plants
confirmed the integration of the gene of interest and excision of the selection marker. Expression of the WD gene was confirmed by northern blot and western blot analyses. A disease resistance assay of the marker-free transgenic plants
exhibited enhanced resistance against B. cinerea strain 40 isolated from P. hybrida. 相似文献
934.
Rizwan Rasheed A. Wahid M. Farooq Iqbal Hussain Shahzad M. A. Basra 《Plant Growth Regulation》2011,65(1):35-45
High temperature strongly hampers the plant growth particularly at early growth stages. In this study, changes in some physiological
and anatomical characteristics and possibility of mitigating the adversities of heat stress by soaking sugarcane nodal buds
in 20 mM proline and glycinebetaine (GB) solutions have been explored. Heat stress reduced the rate of bud sprouting nonetheless
soaking the setts in proline followed by GB was beneficial. In addition, heat stress reduced the bud fresh and dry weights,
generated H2O2, reduced the tissue levels of K+ and Ca2+, while increased the osmolytes synthesis in a time course manner. Heat stress also delayed the emergence and expansion of
new bud leaves, by restricting the number and area of mesophyll cells. It also caused poor and aberrant development and diffused
appearance of mesophyll cells and vascular bundles in the bud leaves. However, soaking of buds in proline and GB solutions
substantially reduced the H2O2 production, improved the accumulation of soluble sugars and protected the developing tissues from heat stress effects; although
proline was more effective than GB. Correlations of various attributes indicated that soaking in GB and proline restricted
the H2O2 generation, improved K+ and Ca2+ contents, and increased the concentrations of free proline, GB and soluble sugars eventually improving the heat tolerance
of buds. Cost-benefit analysis showed that, considering increase in sprouting of buds, soaking in 20 mM solution of both osmoprotectants
is economical. 相似文献
935.
Amber Afroz Zubeda Chaudhry Umer Rashid Ghulam Muhammad Ali Farhat Nazir Javaid Iqbal Muhammad Rashid Khan 《Plant Cell, Tissue and Organ Culture》2011,104(2):227-237
To enhance bacterial wilt resistance in tomato plants and simplify the protocol of Agrobacterium tumefaciens mediated gene transfer, parameters affecting transformation efficiency in tomato have been optimized. A. tumefaciens strain EHA101, harboring a recombinant binary expression vector pTCL5 containing the Xa21 gene under the control of the CaMV 35S promoter was used for transformation. Five cultivars of tomato (Rio Grande, Roma,
Pusa Ruby Pant Bahr and Avinash) were tested for transformation. Transformation efficiency was highly dependent on preculture
of the explants with acetosyringone, acetosyringone in co-cultivation media, shoot regeneration medium and pre-selection after
co-cultivation without selective agent. One week of pre-selection following selection along with 400 μM acetosyringone resulted
in 92.3% transient GUS expression efficiency in Rio Grande followed by 90.3% in Avinash. The presence and integration of the
Xa21 gene in putative transgenic plants was confirmed by polymerase chain reaction (PCR) and Southern blot analyses with 4.5–42.12%
PCR-positive shoots were obtained for Xa21 and hygromycin genes, respectively. Transgenic plants of the all lines showed resistance to bacterial wilt. T1 plants (resulting from self-pollination of transgenic plants) tested against Pseudomonas solanacearum inoculation in glasshouse, showed Mendelian segregation. 相似文献
936.
Dua K Surapaneni SN Kuribayashi S Hafeezullah M Shaker R 《American journal of physiology. Gastrointestinal and liver physiology》2011,301(2):G197-G202
Aerodigestive reflexes triggered by pharyngeal stimulation can protect the airways by clearing fluid from the pharynx. The objective of this study was to determine the relationship between the maximum capacity of fluid that can safely dwell in the hypopharynx [hypopharyngeal safe volume (HPSV)] before spilling into the larynx and the threshold volumes required to trigger pharyngoglottal closure reflex (PGCR), pharyngo-upper esophageal sphincter contractile reflex (PUCR), and reflexive pharyngeal swallow (RPS). Twenty-five healthy volunteers (mean age 24 yr, 8 males) were studied in the semi-inclined supine position. PGCR, PUCR, and RPS were elicited using techniques of concurrent upper esophageal sphincter manometry and pharyngo-laryngoscopy. The hypopharynx was then anesthetized to abolish RPS. HPSV was determined by infusing water in the pharynx, and perfusion was stopped when the infusate reached the superior margin of the interarytenoid fold. The threshold volumes for triggering PGCR, PUCR, and RPS by slow and rapid injections before pharyngeal anesthesia were 0.18 ± 0.02 and 0.09 ± 0.02 ml; 0.20 ± 0.020 and 0.13 ± 0.04 ml; and 0.61 ± 0.04 and 0.4 ± 0.06 ml, respectively. All of the above volumes were significantly smaller than the HPSV (0.70 ± 0.06 ml, P < 0.01) except for the threshold volume to elicit RPS during slow perfusion, which was not significantly different (P = 0.23). We conclude that pharyngeal aerodigestive reflexes are triggered by both slow and rapid pharyngeal perfusion of water at significantly smaller volumes than the maximum capacity of the hypopharynx to safely hold contents without spilling into the airway. These reflexes thereby aid in prevention of aspiration. 相似文献
937.
938.
Saeed M Suzuki R Watanabe N Masaki T Tomonaga M Muhammad A Kato T Matsuura Y Watanabe H Wakita T Suzuki T 《The Journal of biological chemistry》2011,286(43):37264-37273
Viral infections frequently cause endoplasmic reticulum (ER) stress in host cells leading to stimulation of the ER-associated degradation (ERAD) pathway, which subsequently targets unassembled glycoproteins for ubiquitylation and proteasomal degradation. However, the role of the ERAD pathway in the viral life cycle is poorly defined. In this paper, we demonstrate that hepatitis C virus (HCV) infection activates the ERAD pathway, which in turn controls the fate of viral glycoproteins and modulates virus production. ERAD proteins, such as EDEM1 and EDEM3, were found to increase ubiquitylation of HCV envelope proteins via direct physical interaction. Knocking down of EDEM1 and EDEM3 increased the half-life of HCV E2, as well as virus production, whereas exogenous expression of these proteins reduced the production of infectious virus particles. Further investigation revealed that only EDEM1 and EDEM3 bind with SEL1L, an ER membrane adaptor protein involved in translocation of ERAD substrates from the ER to the cytoplasm. When HCV-infected cells were treated with kifunensine, a potent inhibitor of the ERAD pathway, the half-life of HCV E2 increased and so did virus production. Kifunensine inhibited the binding of EDEM1 and EDEM3 with SEL1L, thus blocking the ubiquitylation of HCV E2 protein. Chemical inhibition of the ERAD pathway neither affected production of the Japanese encephalitis virus (JEV) nor stability of the JEV envelope protein. A co-immunoprecipitation assay showed that EDEM orthologs do not bind with JEV envelope protein. These findings highlight the crucial role of the ERAD pathway in the life cycle of specific viruses. 相似文献
939.
Dale Shelton Dimitrios Zabaras Shahid Chohan S Grant Wyllie Peter Baverstock David Leach Robert Henry 《Plant Physiology and Biochemistry》2004,42(11):875-882
Melaleuca alternifolia (Cheel) is an Australia native tree harvested for its monoterpene-rich, essential oil. Monoterpene synthases (E.C. 4.2.3.20) were partially purified from the flush growth of the commercially important, high terpinen-4-ol chemotype of M. alternifolia. The purified fractions produced an acyclic monoterpene, linalool that is not present in the essential oil. To further characterise the monoterpene synthase, a cDNA library was constructed and 500 expressed sequence tags (ESTs) were sequenced to isolate putative terpene synthases. A single clone with similarity to the TspB gene sub-family of angiosperm monoterpene and isoprene synthases was isolated but was truncated at the 5' end. This single clone was used to design a probe for a cDNA library and was applied to isolate a full-length clone. This gene encoded a polypeptide 583 amino acids in length (67 kDa) including a putative transit peptide. Heterologous expression of the gene in Escherichia coli and subsequent assay of the recombinant enzyme did not result in the production of terpinen-4-ol, the major constituent of tea tree oil, or of its precursor sabinene hydrate. Significant quantities of linalool were observed in these assays, and in the assays of monoterpene synthase activity of a native enzyme in vitro, but the racemic nature of the linalool means that it may have a non-enzymatic origin. 相似文献
940.
Uzma Majid Mahmooduzzafar Tariq Omar Siddiqi Muhammad Iqbal 《Acta Physiologiae Plantarum》2014,36(2):307-314
Seeds of Cassia angustifolia Vahl., treated with various concentrations (0, 0.1, 0.15, 0.2 and 0.25 %) of Mancozeb, a broad-spectrum contact fungicide, were sown in field conditions to study the effect of the treatments on lipid peroxidation, proline accumulation and modulation of antioxidant system of seedlings obtained. Significant increase over the control was observed in treated plants for thiobarbituric acid-reactive substances content (up to 207 %), proline content (96 %) and total glutathione content (144 %), whereas the total ascorbate content decreased by 44 %. Increased enzymatic activity was recorded for ascorbate peroxidase (63 %), glutathione reductase (154 %) and superoxide dismutase (109 %), whereas catalase activity decreased by 58 % with 0.25 % Mancozeb treatment. The changes observed were dose-dependent, showing a strong correlation with the level of treatment. 相似文献