排序方式: 共有113条查询结果,搜索用时 15 毫秒
31.
Engineered polyamine accumulation in tomato enhances phytonutrient content,juice quality,and vine life 总被引:16,自引:0,他引:16
Polyamines, ubiquitous organic aliphatic cations, have been implicated in a myriad of physiological and developmental processes in many organisms, but their in vivo functions remain to be determined. We expressed a yeast S-adenosylmethionine decarboxylase gene (ySAMdc; Spe2) fused with a ripening-inducible E8 promoter to specifically increase levels of the polyamines spermidine and spermine in tomato fruit during ripening. Independent transgenic plants and their segregating lines were evaluated after cultivation in the greenhouse and in the field for five successive generations. The enhanced expression of the ySAMdc gene resulted in increased conversion of putrescine into higher polyamines and thus to ripening-specific accumulation of spermidine and spermine. This led to an increase in lycopene, prolonged vine life, and enhanced fruit juice quality. Lycopene levels in cultivated tomatoes are generally low, and increasing them in the fruit enhances its nutrient value. Furthermore, the rates of ethylene production in the transgenic tomato fruit were consistently higher than those in the nontransgenic control fruit. These data show that polyamine and ethylene biosynthesis pathways can act simultaneously in ripening tomato fruit. Taken together, these results provide the first direct evidence for a physiological role of polyamines and demonstrate an approach to improving nutritional quality, juice quality, and vine life of tomato fruit. 相似文献
32.
Apart from gas concentrations, temperature, and pH, generally only the initial conditions can be manipulated in batch culture. Inoculum size and initial conditioned medium concentration represent two important considerations for optimal batch production. Two hybridoma cell lines were used to assess the impact of these initial conditions on population growth and monoclonal antibody productivity in suspension batch culture. Varying initial cell concentration over the range of 1.0 × 105 cells mL-1 to 3.0 × 105 cells mL-1 did not affect maximum product titre or maximum volumetric cell-hours attained. Initial percent of conditioned medium up to 40 percent strongly impacted on population growth and productivity, with initial levels of 30 to 40% conditioned medium reducing or eliminating lag phase and increasing average viable cell density. However, specific productivity and product titre declined with increasing initial percent conditioned medium, even on a per volume of fresh medium basis. Glutamine and glucose depletion or ammonia toxicity could cause depressed product titres when conditioned medium is used. Glutamine and glucose levels can easily be replenished in conditioned medium at minimal cost, and ammonia can be removed. Specific productivity was higher during cyclic batch operating mode than during batch operating mode. This may be because cyclic batch operating mode results in an incidental volume of conditioned medium at the beginning of each cycle. A two stage, cyclic-batch/batch operating mode can be employed to fully utilize medium and maximize product titre. 相似文献
33.
Roshni Gupta Akancha Mishra Hadi Hasan Choudhary Sunil Kumar Narwal Bandita Nayak Pratik Narain Srivastava Satish Mishra 《Molecular microbiology》2020,113(2):478-491
Upon entering its mammalian host, the malaria parasite productively invades two distinct cell types, that is, hepatocytes and erythrocytes during which several adhesins/invasins are thought to be involved. Many surface-located proteins containing thrombospondin Type I repeat (TSR) which help establish host–parasite molecular crosstalk have been shown to be essential for mammalian infection. Previous reports indicated that antibodies produced against Plasmodium falciparum secreted protein with altered thrombospondin repeat (SPATR) block hepatocyte invasion by sporozoites but no genetic evidence of its contribution to invasion has been reported. After failing to generate Spatr knockout in Plasmodium berghei blood stages, a conditional mutagenesis system was employed. Here, we show that SPATR plays an essential role during parasite's blood stages. Mutant salivary gland sporozoites exhibit normal motility, hepatocyte invasion, liver stage development and rupture of the parasitophorous vacuole membrane resulting in merosome formation. But these mutant hepatic merozoites failed to establish a blood stage infection in vivo. We provide direct evidence that SPATR is not required for hepatocyte invasion but plays an essential role during the blood stages of P. berghei. 相似文献
34.
Erki Enkvist Gerda Raidaru Asko Uri Roshni Patel Catherine Redick José L. Boyer 《Nucleosides, nucleotides & nucleic acids》2013,32(2):141-157
Alkylation of adenine in solution and on solid phase was accelerated by phosphazene base P1-tBu compared to mineral bases. The reactions in solution afforded regioselectively the appropriate N9-alkylated adenines with high preparative yields while the reaction with polystyrene resin-bound N-bromoacetylated peptides gave three regioisomers (alkylated at the N9, N7, and N3 position of adenine) in a 4:2:1 molar ratio. Ten novel nonphosphate nucleotide analogues were tested in an ADP-induced platelet aggregation assay. 相似文献
35.
Journal of Ichthyology - Etroplus suratensis (Bloch, 1790) is a highly exploited endemic cichlid fish species inhabiting the Cochin Estuary situated on the South-west coast of India. The study was... 相似文献
36.
Hirsch-Reinshagen V Chan JY Wilkinson A Tanaka T Fan J Ou G Maia LF Singaraja RR Hayden MR Wellington CL 《Journal of lipid research》2007,48(4):914-923
ABCA1-deficient mice have low levels of poorly lipidated apolipoprotein E (apoE) and exhibit increased amyloid load. To test whether excess ABCA1 protects from amyloid deposition, we crossed APP/PS1 mice to ABCA1 bacterial artificial chromosome (BAC) transgenic mice. Compared with wild-type animals, the ABCA1 BAC led to a 50% increase in cortical ABCA1 protein and a 15% increase in apoE abundance, demonstrating that this BAC supports modest ABCA1 overexpression in brain. However, this was observed only in animals that do not deposit amyloid. Comparison of ABCA1/APP/PS1 mice with APP/PS1 controls revealed no differences in levels of brain ABCA1 protein, amyloid, Abeta, or apoE, despite clear retention of ABCA1 overexpression in the livers of these animals. To further investigate ABCA1 expression in the amyloid-containing brain, we then compared ABCA1 mRNA and protein levels in young and aged cortex and cerebellum of APP/PS1 and ABCA1/APP/PS1 animals. Compared with APP/PS1 controls, aged ABCA1/APP/PS1 mice exhibited increased ABCA1 mRNA, but not protein, selectively in cortex. Additionally, ABCA1 mRNA levels were not increased before amyloid deposition but were induced only in the presence of extensive Abeta and amyloid levels. These data suggest that an induction of ABCA1 expression may be associated with late-stage Alzheimer's neuropathology. 相似文献
37.
The microtubule cytoskeleton serves as a primary spatial regulator of cell shape. As part of their function, microtubules appear to activate or inhibit the actin cytoskeleton at specific locations at the cell cortex for cell polarization, cell migration and cytokinesis. Recent studies reveal molecular insights into these processes. Regulators of the actin cytoskeleton, such as activators of formin and Rho GTPases, are transported to specific sites on the cortex by riding on the plus ends of microtubules. 相似文献
38.
OBJECTIVE: To examine the observation that some mucinous carcinomas have a micropapillary pattern and are mucinous variants of the highly angioinvasive infiltrating micropapillary carcinomas (IMPC). STUDY DESIGN: We evaluated cytologic findings of 13 IMPC and 55 mucinous carcinomas for comparative features. RESULTS: In mucinous carcinomas, 37 of 50 (74%) had a micropapillary pattern. This group included 27 cases with pure mucinous micropapillary morphology (MUMPC), 8 MUMPC associated with a ductal carcinoma of the IMPC type (MUIDC) and 2 cases of mixed mucinous carcinomas with an MUMPC and a solid variant ofpapillary carcinoma (SVPC) component. On cytology both IMPC and mucinous carcinomas with micropapillary pattern demonstrated the micropapillary pattern, that is, angulated clusters or abortive papillae and ball-like clusters. However, the IMPC smears revealed numerous singly scattered tumor cells and larger fragments with shrub-like branching and the MUMPC had psammoma bodies. The mixed MUMPC and SVPC showed the classic cytologic features of MUMPC admixed with abundant singly dispersed tumor cells in the background representing the SVPC component. CONCLUSION: Although IMPC and the MUMPC share the micropapillary pattern on histologic examination, mucin alters the appearances in aspirates. Recognition of this morphologic spectrum will help in understanding the behavior of these tumors. 相似文献
39.
Endometriosis is a complex disorder of the female reproductive system where endometrial tissue embeds and grows at extrauterine location leading to inflammation and pain. Hundreds of polymorphisms in several genes have been studied as probable risk factors of this debilitating disease. Bioinformatics tools have come a long way in augmenting the search for putative functional polymorphisms in human diseases. In this study we have explored 16 genes involved in the detoxification of xenobiotic chemicals that are implicated in endometriosis by utilising publically available programs like SIFT, Polyphen, Panther, FastSNP, SNPeffect and PhosSNP. The variations among different ethnic populations of the SNPs were studied. We then calculated the extent to which bioinformatics based predictions are concurrent with real world epidemiological, genotyping studies using a set of SNPs that have been studied in endometriosis case–control studies. Our study shows that there is a significant positive correlation (r = 0.569, p < 0.005) between the summary of the predicted scores taken from 4 different servers and the odds ratio found from epidemiological studies. This report has identified and catalogued various deleterious SNPs that could be important in endometriosis and could aid in further analysis by in vitro and in vivo methods for the better understanding of the disease pathophysiology. 相似文献
40.
Roshni Roy Navonil De Sarkar Sandip Ghose Ranjan R Paul Anindita Ray Indranil Mukhopadhyay Bidyut Roy 《Journal of biomedical science》2014,21(1):48