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A procedure for the stimulation of axillary bud developmentfrom young shoots of maize, their subculture to root-inducingmedia and transfer as rooted plants to soil is described. Axillarybud development was enhanced by the addition of kinetin andauxin to the culture medium. Root initiation on explanted axillarybuds, while successful with some cultivars, was variable. Anumber of mature plants with normal tassels and ears were producedfrom the lowermost buds of an original stem explant. Buds fromhigher positions on the explant exhibited different potentialitieswith some, those normally from cob producing nodes, producingshort-stalked plants with terminal female influorescences. Agradient of bud potentiality along the stem appears to be establishedextremely early after each is initiated. Zea mays., corn, maize, shoot tip culture, clone, vegetative propagation 相似文献
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A Puri R Sethi B Singh SK Dwivedi VS Narain RK Saran VK Puri 《Indian pacing and electrophysiology journal》2009,9(3):186-189
A 25-year-old previously asymptomatic pregnant woman at 36 weeks'' gestation was noticed to have repetitive monomorphic ventricular tachycardia. A dilated left ventricle with moderately reduced systolic function was found on echocardiographic examination. This is a very rare presentation of peripartum cardiomyopathy (PPCMP) presenting with repetitive monomorphic ventricular tachycardia. 相似文献
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The effect of neurotensin on submaximally-stimulated hepatobiliary and pancreatic secretion was studied in 6 healthy subjects. An intravenous infusion of neurotensin 1.4 ± 0.3 pmol/kg/min, designed to reproduce plasma neurotensin immunoreactivity levels within the physiological range, produced a significant increase in pancreatic bicarbonate output. Plasma concentrations of pancreatic polypeptide rose by 83 ± 16 pmol/l and were associated with a small reduction in trypsin, but no significant change in bilirubin outputs. 相似文献
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A recently silenced, duplicate PgiC locus in Clarkia 总被引:1,自引:0,他引:1
Previous electrophoretic analysis showed that 17 diploid species of the
wildflower Clarkia (Onagraceae) have two cytosolic isozymes of
phosphoglucose isomerase (PGIC; EC 5.3.1.9), whereas 15 other diploid
species have a single PGIC. Molecular studies revealed that the two
isozymes in the former species are encoded by duplicate genes, PgiC1 and
PgiC2, whereas the single isozyme in the latter is always encoded by PgiC1.
Phylogenetic analysis of the nucleotide sequences implied that PgiC2 was
silenced four times independently in the genus. Here we describe a psi
PgiC2 from C. mildrediae, a species in which only PgiC1 is expressed. The
discovery of the psi PgiC2 is significant because it confirms a formal
prediction of the phylogenetic analysis. The psi PgiC2 includes 5,039
nucleotides corresponding to 18 of the 23 exons of PgiC, as well as the
intervening introns and 3' nontranslated region. The absence of an increase
of nucleotide substitutions in its "exons" suggests that the gene was
silenced recently. The present study appears to be the first to establish
that a specific duplicate gene locus regularly expressed in a group of
related plant species has been silenced in one of them. The multiple
independent silencings of PgiC2 suggest that it remained functional but
inessential in ancestral lineages. We discuss the possibility that PgiC2
may have been preserved in these lineages by selection against mutants
causing defective PGIC1- PGIC2 heterodimers.
相似文献
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Aulus EAD Barbosa Érika VS Albuquerque Maria CM Silva Djair SL Souza Osmundo B Oliveira-Neto Arnubio Valencia Thales L Rocha Maria F Grossi-de-Sa 《BMC biotechnology》2010,10(1):44
Background
Coffee is an important crop and is crucial to the economy of many developing countries, generating around US70 billion per year. There are 115 species in the < i > Coffea < /i > genus, but only two, < i > C. arabica < /i > and < i > C. canephora < /i > , are commercially cultivated. Coffee plants are attacked by many pathogens and insect-pests, which affect not only the production of coffee but also its grain quality, reducing the commercial value of the product. The main insect-pest, the coffee berry borer ( < i > Hypotheneumus hampei < /i > ), is responsible for worldwide annual losses of around US70 billion per year. There are 115 species in the Coffea genus, but only two, C. arabica and C. canephora, are commercially cultivated. Coffee plants are attacked by many pathogens and insect-pests, which affect not only the production of coffee but also its grain quality, reducing the commercial value of the product. The main insect-pest, the coffee berry borer (Hypotheneumus hampei), is responsible for worldwide annual losses of around US500 million. The coffee berry borer exclusively damages the coffee berries, and it is mainly controlled by organochlorine insecticides that are both toxic and carcinogenic. Unfortunately, natural resistance in the genus Coffea to H. hampei has not been documented. To overcome these problems, biotechnological strategies can be used to introduce an α-amylase inhibitor gene (α-AI1), which confers resistance against the coffee berry borer insect-pest, into C. arabica plants. 相似文献8.
Background
Growth factor receptor-bound protein 14 (Grb14) is an adapter protein implicated in receptor tyrosine kinase signaling. Grb14 knockout studies highlight both the positive and negative roles of Grb14 in receptor tyrosine kinase signaling, in a tissue specific manner. Retinal cells are post-mitotic tissue, and insulin receptor (IR) activation is essential for retinal neuron survival. Retinal cells express protein tyrosine phosphatase-1B (PTP1B), which dephosphorylates IR and Grb14, a pseudosubstrate inhibitor of IR. This project asks the following major question: in retinal neurons, how does the IR overcome inactivation by PTP1B and Grb14?Results
Our previous studies suggest that ablation of Grb14 results in decreased IR activation, due to increased PTP1B activity. Our research propounds that phosphorylation in the BPS region of Grb14 inhibits PTP1B activity, thereby promoting IR activation. We propose a model in which phosphorylation of the BPS region of Grb14 is the key element in promoting IR activation, and failure to undergo phosphorylation on Grb14 leads to both PTP1B and Grb14 exerting their negative roles in IR. Consistent with this hypothesis, we found decreased phosphorylation of Grb14 in diabetic type 1 Ins2Akita mouse retinas. Decreased retinal IR activation has previously been reported in this mouse line.Conclusions
Our results suggest that phosphorylation status of the BPS region of Grb14 determines the positive or negative role it will play in IR signaling.9.
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The extractable GA-like substances from seedlings of both doubleand single genotypes of Nigella damascena areequally compartmentalized between AES and HWS fractions. However,when seedlings were floated on an aqueous solution of kinetinprior to extraction, the compart-mentalization profiles werealtered differentially. The levels of the AES fraction fromdouble tissues increased concomitantly with adecrease in the level of the HWS fraction. No detectable shiftin the activity of AES and HWS fractions was observed in singleseedlings. This differential response to kinetin parallels otherobservations on these two genotypes and substantiates an interpretationthat these two morphologic traits are associated with ratherdifferent capacities to metabolize GAs. 相似文献