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David B. Collinge Dawn E. Milligan J. Maxwell Dow Graham Scofield Michael J. Daniels 《Plant molecular biology》1987,8(5):405-414
Xanthomonas campestris pv. vitians, a pathogen of lettuce, elicits a hypersensitive response within 12 hours of inoculation into Brassica leaves, characterized by tissue collapse, loss of membrane integrity, vein blockage and melanin production. In contrast, the compatible pathogen, X. c. pv. campestris, has no visible effects on leaves for 48 hours, after which inoculated areas show chlorosis which eventually spreads, followed by rotting.mRNA was prepared from leaves inoculated with suspensions of both pathovars or with sterile medium up to 24 hours following inoculation. In vitro translation of total and poly A+ RNA in rabbit reticulocyte lysate in the presence of 35S methionine followed by separation of the polypeptide products by 2D-PAGE, allowed comparison of the effects of these treatments on plant gene expression. Major changes in gene expression were observed as a consequence of the inoculation technique. In addition, after inoculation with X. c. vitians, up to fifteen additional major polypeptides appeared or greatly increased by four hours. Some of these had disappeared by nine hours and several more had appeared. No major polypeptides disappeared or decreased greatly in intensity following inoculation with X. c. vitians. 相似文献
4.
Pseudomonas aeruginosa outer membrane protein F produced inEscherichia coli retains vaccine efficacy
Janice M. Matthews-Greer Dawn E. Robertson Linda B. Gilleland Dr. Harry E. Gilleland Jr. 《Current microbiology》1990,20(3):171-175
Pseudomonas aeruginosa outer membrane protein F was purified by extraction from polyacrylamide gels of cell envelope proteins of anEscherichia coli strain expressing the cloned gene for protein F. Antisera directed against protein F purified fromP. aeruginosa PAO1 reacted with thisE. coli strain by immunofluorescence assay and immunoblotting, whereas these antisera were nonreactive withE. coli strains lacking thePseudomonas protein F gene. The protein F purified from thisE. coli strain was used to immunize mice by intramuscular injection of 10 µg of protein F preparation on days 1 and 14, followed by burn and challenge of the mice on day 28. As compared with control mice immunized withE. coli K-12 lipopolysaccharide, immunization with theE. coli-derived protein F afforded significant protection against subsequent challenge with heterologous Fisher-Devlin immunotype 5 and 6 strains ofP. aeruginosa. Antisera from mice immunized with theE. coli-derived protein F reacted at bands corresponding to protein F and 2-mercaptoethanol-modified protein F upon immunoblotting against cell envelope proteins of the PAO1, immunotype 5, and immunotype 6 strains ofP. aeruginosa and theE. coli strain containing the cloned F gene, but failed to react at these sites in anE. coli strain lacking the F gene. These data demonstrate thatP. aeruginosa protein F produced inE. coli through genetic engineering techniques retains its vaccine efficacy in the complete absence of anyP. aeruginosa lipopolysaccharide. 相似文献
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Eukaryotic cells normally replicate their DNA only once between mitoses. Unlike G1 nuclei, intact G2 nuclei do not replicate during incubation inXenopusegg extract. However, artificial permeabilization of the nuclear membrane of G2 nuclei allows induction of new initiations byXenopusegg extract. This is consistent with the action of a replication licensing factor which is believed to enter the nucleus when the nuclear membrane breaks down at mitosis. Here, we show that G2 nuclei will initiate a new round of replication in the absence of nuclear membrane permeabilization, if they are preexposed to protein kinase inhibitorsin vivo.Competence to rereplicate is generated within 30 min of drug treatment, well before the scheduled onset of mitosis. This demonstrates that a protein kinase-dependent mechanism is continually active in G2 phase to actively prevent regeneration of replication capacity in mammalian cells. Kinase inhibition in G2 cells causes nuclear accumulation of replication protein A. Rereplication of kinase-inhibited G2 nuclei also depends on factors supplied byXenopusegg extract, which are distinct from those required for replication licensing. 相似文献
6.
Karen van Zee Dawn A. Baertlein Steve E. Lindow Nicholas Panopoulos Tony H. H. Chen 《Plant molecular biology》1996,30(1):207-211
The bacterial ice nucleation gene inaZ confers production of ice nuclei when transferred into transgenic plants. Conditioning of the transformed plant tissue at temperatures near 0°C greatly increased the ice nucleation activity in plants, and maximum ice nucleation activity was achieved only after low-temperature conditioning for about 48 h. Although the transgenic plants contain similar amounts of inaZ mRNA at both normal and low temperatures, low temperatures are required for accumulation of INAZ protein. We propose that the stability of the INAZ protein and thus ice nucleation activity in the transgenic plants is enhanced by low-temperature conditioning. 相似文献
7.
Michael M. Burrell Peter J. Mooney Margaret Blundy Dawn Carter Fiona Wilson John Green Keith S. Blundy Tom ap Rees 《Planta》1994,194(1):95-101
The aim of this work was to discover whether genetic manipulation of 6-phosphofructokinase [EC 2.7.1.11; PFK(ATP)] influenced the rate of respiration of tuber tissue of Solanum tuberosum L. Transgenic plants were produced that contained the coding sequence of the Escherichia coli pfkA gene linked to a patatin promoter. Expression of this chimaeric gene in tubers resulted in a 14to 21-fold increase in the maximum catalytic activity of PFK(ATP) without affecting the activities of the other glycolytic enzymes. Tubers, and aged disks of tuber tissue, from transformed plants showed no more than a 30% fall in the content of hexose 6-monophosphates; the other intermediates of glycolysis increased threeto eightfold. Fructose-2,6-bisphosphate was barely detectable in aged disks of transformed tubers. The relative rates of 14CO2 production from [1-14C]-and [6-14C]-glucose supplied to disks of transformed and control tubers were similar. Oxygen uptake and CO2 production by aged disks of transformed tubers did not differ significantly from those from control tubers. The same was true of CO2 production, in air, and in nitrogen, for tuber tissue. It is concluded that PFK(ATP) does not dominate the control of respiration in potato tubers.Abbreviations Fru2,6bisP
fructose-2,6-bisphosphate
- FW
freshweight
- GUS
-glucuronidase
- PFK(ATP)
6-phosphofructokinase
- PFK(PPi)
pyrophosphate: fructose-6-phosphate 1-phosphotransferase 相似文献
8.
Genevieve E. Davis Mark F. Baumgartner Peter J. Corkeron Joel Bell Catherine Berchok Julianne M. Bonnell Jacqueline Bort Thornton Solange Brault Gary A. Buchanan Danielle M. Cholewiak Christopher W. Clark Julien Delarue Leila T. Hatch Holger Klinck Scott D. Kraus Bruce Martin David K. Mellinger Hilary Moors‐Murphy Sharon Nieukirk Douglas P. Nowacek Susan E. Parks Dawn Parry Nicole Pegg Andrew J. Read Aaron N. Rice Denise Risch Alyssa Scott Melissa S. Soldevilla Kathleen M. Stafford Joy E. Stanistreet Erin Summers Sean Todd Sofie M. Van Parijs 《Global Change Biology》2020,26(9):4812-4840
Six baleen whale species are found in the temperate western North Atlantic Ocean, with limited information existing on the distribution and movement patterns for most. There is mounting evidence of distributional shifts in many species, including marine mammals, likely because of climate‐driven changes in ocean temperature and circulation. Previous acoustic studies examined the occurrence of minke (Balaenoptera acutorostrata) and North Atlantic right whales (NARW; Eubalaena glacialis). This study assesses the acoustic presence of humpback (Megaptera novaeangliae), sei (B. borealis), fin (B. physalus), and blue whales (B. musculus) over a decade, based on daily detections of their vocalizations. Data collected from 2004 to 2014 on 281 bottom‐mounted recorders, totaling 35,033 days, were processed using automated detection software and screened for each species' presence. A published study on NARW acoustics revealed significant changes in occurrence patterns between the periods of 2004–2010 and 2011–2014; therefore, these same time periods were examined here. All four species were present from the Southeast United States to Greenland; humpback whales were also present in the Caribbean. All species occurred throughout all regions in the winter, suggesting that baleen whales are widely distributed during these months. Each of the species showed significant changes in acoustic occurrence after 2010. Similar to NARWs, sei whales had higher acoustic occurrence in mid‐Atlantic regions after 2010. Fin, blue, and sei whales were more frequently detected in the northern latitudes of the study area after 2010. Despite this general northward shift, all four species were detected less on the Scotian Shelf area after 2010, matching documented shifts in prey availability in this region. A decade of acoustic observations have shown important distributional changes over the range of baleen whales, mirroring known climatic shifts and identifying new habitats that will require further protection from anthropogenic threats like fixed fishing gear, shipping, and noise pollution. 相似文献
10.
Thermoregulation in free-ranging Nycteris thebaica (Nycteridae) during winter: No evidence of torpor
Bats are among the most heterothermic mammals, with nearly all species investigated under free-ranging conditions to date exhibiting some degree of daily torpor and/or hibernation. We investigated thermoregulation during late winter by seven Nycteris thebaica in a warm, semi-arid habitat in northern South Africa, using temperature-sensitive transmitters to measure skin temperature (Tskin). Unexpectedly, we found no evidence for any expression of daily torpor or hibernation based on a total of 86 days of data from 7 bats (one male and six females), despite air temperatures as low as ~10 °C. Instead, daytime Tskin was distributed unimodally with most values in the 33–35 °C range, and a minimum Tskin of 28.4 °C at a roost temperature of 24.6 °C. There are several possible reasons why N. thebaica may avoid torpor, including predation in roosts, and the long nightly foraging periods of this species compared to many others. 相似文献