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191.
Joanne H.E. Ross Denis J. Murphy 《The Plant journal : for cell and molecular biology》1996,9(5):625-637
A large, heterogeneous, highly expressed gene family encoding oleosin-like proteins is described in the Brassicaceae. íeven related cDNA sequences were isolated from Brassica napus anther mRNA using RACE-PCR and compared with other recently described anther-specific oleosin-like genes from B. napus. The expression patterns of four representative members of this diverse gene family were analyzed by Northern blotting and in situ hybridization. In all cases, the genes were expressed specifically in the tapetum of 3–5 mm B. napus buds, which contained microspores at the late-vacuolate and bicellular stages of development. The predicted protein products are ordered into subclasses, each of which has a characteristic C-terminal domain, containing different amino acid motifs or repeated residues. Tryphine (pollen coat) fractions from mature B. napus pollen were found to be particularly enriched in polypeptides of apparent molecular weights 32–38 kDa, plus numerous less abundant polypeptides of less than 15 kDa. The N-terminal 15–20 residues of three of these polypeptides (12, 32 and 38 kDa) were found by microsequencing to be identical to parts of the predicted amino acid sequences of three of the tapetal-expressed oleosin-like genes. This indicates the possibility of post-translational modification of these proteins resulting in a cleavage of the primary translation products in order to generate the mature tryphine polypeptides. These data imply that a large and diverse group of oleosin-like proteins is synthesized in the tapeturn of B. napus anthers and that following tapetal degradation, these proteins, possibly in modified form, then relocate to the developing microspores where they eventually constitute some of the major components of the extracellular tryphine of mature pollen grains. These proteins share a conserved 70 amino acid residue hydrophobic domain and are related structurally to the seed-specific intracellular oleosins, although their biological function may be different. 相似文献
192.
The gibberellin (GA)-biosynthesis mutations, lh
i
, ls and Ie
5839
have been used to investigate the role(s) of the GAs in seed development of the garden pea (Pisum sativum L.). Seeds homozygous for lh
i
possess reduced GA levels, are more likely to abort during development, and weigh less at harvest, compared with wild-type seeds due to expression of the lh
i
mutation in the embryo and/ or endosperm. Compared with wild-type seeds, the lh
i
mutation reduces endogenous GA1 and gibberellic acid (GA3) levels in the embryo/endosperm a few days after anthesis and fertilizing lh
i
plants with wild-type pollen dramatically increases GA1 and GA3 levels in the embryo/ endosperm and restores normal seed development. By contrast, the ls and le
5839
mutations do not appear to reduce GA levels in the embryo/endosperm of seeds a few days after anthesis, and do not affect embryo or endosperm development. However, both the ls and lh
i
mutations substantially reduce endogenous GA levels in embryos at contact point (the first day the liquid endosperm disappears). Levels of GAs in seeds from crosses involving the ls and lh
i
mutations suggest that GAs are synthesised in both the embryo/endosperm and testa and that the expression of ls depends on the tissue and developmental stage examined. These results suggest that GAs (possibly GA1 and/or GA3) play an important role early in pea seed development by regulating the development of the embryo and/or endosperm. By contrast, the high GA levels found in wild-type seeds at contact point (and beyond) do not appear to have a physiological role in seed development.Abbreviations GAn
gibberellin An
- DAA
days after anthesis
- WT
wild-type
We thank Noel Davies, Katherine McPherson and Peter Bobbi for technical assistance, Professor L. Mander (ANU, Canberra) for dideuterated GA standards, and the Australian Research Council and Frontier Research Program, The Institute of Physical and Chemical Research (RIKEN, Japan), for financial support. 相似文献
193.
When compared to agarose solidified media in small petri dishes, membrane rafts used in conjunction with liquid induction media significantly improved anther culture response in the Australian, malting-quality, spring barley cultivar Clipper. In contrast, the German cultivar Gimpel did not show an increased response on rafts.Abbreviations BA
6-benzylaminopurine
- IAA
indoleacetic acid
- DH
doubled haploid 相似文献
194.
Crosses were made between the Asian cockroach,Blattella asahinai Mizukubo, and resistant strains of the German cockroach,B. germanica (L.), to assess the transfer of pyrethroid resistance to the progeny and to study the inheritance mechanism(s) involved.
It was shown that the strain of Asian cockroaches studied was susceptible to four pyrethroids. F1 progeny were essentially susceptible to the same compounds. Tests with F2 progeny and those from backcrosses to the resistant parent indicated that the data for each pyrethroid fit an hypothesis
of simple, autosomal, nearly completely recessive inheritance. The results are discussed from the standpoint of the impact
of the Asian genome on the inheritance mechanism(s). 相似文献
195.
Joanna K. Bowen Matthew D. Templeton Keith R. Sharrock Ross N. Crowhurst Erik H. A. Rikkerink 《Molecular & general genetics : MGG》1995,246(2):196-205
The feasibility of performing routine transformation-mediated mutagenesis in Glomerella cingulata was analysed by adopting three one-step gene disruption strategies targeted at the pectin lyase gene pnIA. The efficiencies of disruption following transformation with gene replacement- or gene truncation-disruption vectors were compared. To effect replacement-disruption, G. cingulata was transformed with a vector carrying DNA from the pnlA locus in which the majority of the coding sequence had been replaced by the gene for hygromycin B resistance. Two of the five transformants investigated contained an inactivated pnlA gene (pnlA
–
);both also contained ectopically integrated vector sequences. The efficacy of gene disruption by transformation with two gene truncation-disruption vectors was also assessed. Both vectors carried a 5and 3truncated copy of the pnlA coding sequence, adjacent to the gene for hygromycin B resistance. The promoter sequences controlling the selectable marker differed in the two vectors. In one vector the homologous G. cingulata gpdA promoter controlled hygromycin B phosphotransferase expression (homologous truncation vector), whereas in the second vector promoter elements were from the Aspergillus nidulans gpdA gene (heterologous truncation vector). Following transformation with the homologous truncation vector, nine transformants were analysed by Southern hybridisation; no transformants contained a disrupted pnlA gene. Of nineteen heterologous truncation vector transformants, three contained a disrupted pnlA gene; Southern analysis revealed single integrations of vector sequence at pnlA in two of these transformants. pnlA mRNA was not detected by Northern hybridisation in pnlA-transformants. pnlA-transformants failed to produce a PNLA protein with a pI identical to one normally detected in wild-type isolates by silver and activity staining of isoelectric focussing gels. Pathogenesis on Capsicum and apple was unaffected by disruption of the pnlA gene, indicating that the corresponding gene product, PNLA, is not essential for pathogenicity. Gene disruption is a feasible method for selectively mutating defined loci in G. cingulata for functional analysis of the corresponding gene products. 相似文献
196.
We describe genetic structure at various scales in native populations of the fire ant Solenopsis invicta using two classes of nuclear markers, allozymes and microsatellites, and markers of the mitochondrial genome. Strong structure was found at the nest level in both the monogyne (single queen) and polygyne (multiple queen) social forms using allozymes. Weak but significant microgeographic structure was detected above the nest level in polygyne populations but not in monogyne populations using both classes of nuclear markers. Pronounced mitochondrial DNA (mtDNA) differentiation was evident also at this level in the polygyne form only. These microgeographic patterns are expected because polygyny in ants is associated with restricted local gene flow due mainly to limited vagility of queens. Weak but significant nuclear differentiation was detected between sympatric social forms, and strong mtDNA differentiation also was found at this level. Thus, queens of each form seem unable to establish themselves in nests of the alternate type, and some degree of assortative mating by form may exist as well. Strong differentiation was found between the two study regions using all three sets of markers. Phylogeographic analyses of the mtDNA suggest that recent limitations on gene flow rather than longstanding barriers to dispersal are responsible for this large-scale structure. 相似文献
197.
Glucose Transporter (GLUT-4) Is Targeted to Secretory Granules in Rat Atrial Cardiomyocytes 总被引:6,自引:2,他引:4
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Jan W. Slot Gabriella Garruti Sally Martin Viola Oorschot George Posthuma Edward W. Kraegen Ross Laybutt Gatan Thibault David E. James 《The Journal of cell biology》1997,137(6):1243-1254
The insulin-responsive glucose transporter GLUT-4 is found in muscle and fat cells in the transGolgi reticulum (TGR) and in an intracellular tubulovesicular compartment, from where it undergoes insulindependent movement to the cell surface. To examine the relationship between these GLUT-4–containing compartments and the regulated secretory pathway we have localized GLUT-4 in atrial cardiomyocytes. This cell type secretes an antihypertensive hormone, referred to as the atrial natriuretic factor (ANF), in response to elevated blood pressure. We show that GLUT-4 is targeted in the atrial cell to the TGR and a tubulo-vesicular compartment, which is morphologically and functionally indistinguishable from the intracellular GLUT-4 compartment found in other types of myocytes and in fat cells, and in addition to the ANF secretory granules. Forming ANF granules are present throughout all Golgi cisternae but only become GLUT4 positive in the TGR. The inability of cyclohexamide treatment to effect the TGR localization of GLUT-4 indicates that GLUT-4 enters the ANF secretory granules at the TGR via the recycling pathway and not via the biosynthetic pathway. These data suggest that a large proportion of GLUT-4 must recycle via the TGR in insulin-sensitive cells. It will be important to determine if this is the pathway by which the insulin-regulatable tubulo-vesicular compartment is formed. 相似文献
198.
Carol A. Sheppard Peter B. Simpson Alan H. Sharp Frederick C. Nucifora Christopher A. Ross †G. David Lange James T. Russell 《Journal of neurochemistry》1997,68(6):2317-2327
Abstract: We have examined the mechanisms that underlie Ca2+ wave propagation in cultured cortical astrocytes. Norepinephrine evoked Ca2+ waves in astrocytes that began at discrete initiation loci and propagated throughout the cell by regenerative amplification at a number of cellular sites, as shown by very high Ca2+ release rates at these regions. We have hypothesized previously that domains displaying elevated Ca2+ release kinetics in astrocytes may correspond to sites of high inositol 1,4,5-trisphosphate receptor (InsP3 R) density. To examine this possibility, we compared the distribution pattern of endoplasmic reticulum (ER) and InsP3 Rs with Ca2+ release kinetics in subcellular regions during propagation of norepinephrine-evoked waves. 3,3'-Dihexyloxacarbocyanine iodide staining revealed that the ER in astrocytes exists as a meshwork of membranes extending throughout the cells, including fine processes. A specific antibody directed against type 2 InsP3 Rs (InsP3 R2) detected a 260-kDa band in western blotting of astrocyte membranes. Immunocytochemistry using this antibody stained the entire ER system in a punctate, variegated manner. When Ca2+ responses and InsP3 R2 immunofluorescence were compared in the same cell, domains of elevated Ca2+ response kinetics (high amplitude and rapid rate of rise) showed significant positive correlation with high local intensity of InsP3 R2 staining. It appears, therefore, that specializations in the ER responsible for discrete local Ca2+ release sites that support regenerative wave propagation include increased levels of InsP3 R2 expression. 相似文献
199.
Homogenates of specific brain regions of three sensory systems (auditory, olfactory, and visual) were prepared from pigmented Long-Evans Hooded rats and assayed for amino acid concentrations and activities of glutaminase, aspartate aminotransferase (total, cytosolic, and, by difference, mitochondrial), malate dehydrogenase, lactate dehydrogenase, and choline acetyltransferase. Comparing the quantitative distributions among regions revealed significant correlations between AAT and aspartate, between glutaminase and glutamate, between glutamate and glutamine, and between AAT plus glutaminase, or glutaminase alone, and the sum of aspartate, glutamate, and GABA, suggesting a metabolic pathway involving the synthesis of a glutamate pool as precursor to aspartate and GABA. Of the inhibitory transmitter amino acids, GABA concentrations routinely exceeded those of glycine, but glycine concentrations were relatively high in brainstem auditory structures. 相似文献
200.
G. M. Morris J. W. Hopewell G. A. Ross E. Whitehouse D. Wilding C. A. Scott 《Cell proliferation》1995,28(2):73-84
The daily oral administration of 3 ml of two oils (So-5407 and So-1129) containing essential fatty acids (EFAs) for 16 weeks resulted in a transient increase in cell proliferative activity in the skin of female Large White pigs. The So-5407 oil contained 7% gamma-linolenic acid (GLA) whereas So-1129 was an oil of similar composition, but with no GLA. Hyperplasia of the epidermis was observed after the administration of both oils, and this was characterized by an increase in the size of the rete pegs. The maximum effect occurred at 4 weeks after the start of oil administration, at which time the number of viable cell layers had increased by a factor of approximately 1.5, and mean epidermal thickness (excluding the stratum corneum) was approximately 40% greater than that of the epidermis prior to oil administration. There was a marked increase in the labelling index (LI) of the basal cell layer of the epidermis in pigs receiving So-5407. Maximum LIs were quantified at 4 weeks after the start of administration and were 18.8 ± 1.3% and 13.1 ± 1.7% for pigs receiving So-5407 and So-1129, respectively. After this time the LI declined prgressively and had returned to values within normal limits (P>0.1) by 8 weeks after the start of administration of both oils. A similar pattern of change in the LI was seen in the follicular epithelium, although the peak values at 4 weeks after the start of oil administration of 12.2 ± 1.8% and 10.8 ± 0.9 for the groups receiving So-5407 and So-1129, respectively, were lower than in the epidermis. Labelled cells were also counted in the papillary dermis and maximum values were again seen at 4 weeks after the start of oil administration. Of the two oils, So-1129 had the greatest effect, with the number of labelled cells in the papillary dermis being a factor of three to four-fold higher than in skin prior to oil administration, between 2 and 12 weeks after the start of administration. 相似文献