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91.
High-frequency stable transformation of cotton (Gossypium hirsutum L.) by particle bombardment of embryogenic cell suspension cultures 总被引:6,自引:0,他引:6
K. Rajasekaran R. L. Hudspeth J. W. Cary D. M. Anderson T. E. Cleveland 《Plant cell reports》2000,19(6):539-545
Stable transformation of cotton (Gossypium hirsutum L.) at a high frequency has been obtained by particle bombardment of embryogenic cell suspension cultures. Transient and
stable expression of the β-glucuronidase (GUS) gene was monitored in cell suspension cultures. Transient expression, measured 48 h after bombardment,
was abundant, and stable expression was observed in over 4% of the transiently expressing cells. The high efficiency of stable
expression is due to the multiple bombardment of rapidly dividing cell suspension cultures and the selection for transformed
cells by gradually increasing the concentrations of the antibiotic Geneticin (G418). Southern analysis indicated a minimum
transgene copy number of one to four in randomly selected plants. Fertile plants were obtained from transformed cell cultures
less than 3 months old. However, transgenic and control plants from cell cultures older than 6 months produced plants with
abnormal morphology and a high degree of sterility.
Received: 20 January 1999 / Revision received: 1 October 1999 / Accepted: 11 October 1999 相似文献
92.
Frank R. Chen Theodore Quan Joseph E. Manzi Alex Gu Chapman Wei Sean Tabaie Marc Chodos Cary B. Chapman Kane O. Pryor Jiabin Liu 《The Iowa orthopaedic journal》2022,42(1):113
BackgroundTotal ankle arthroplasty (TAA) is performed for ankle arthritis and there has been interest investigating which anesthetic method is the best choice in order to optimize perioperative outcomes. In this study, we compared postoperative complications after TAA for patients receiving either 1) general anesthesia alone or 2) general anesthesia plus regional anesthesia.MethodsPatients undergoing primary TAA from 2007 to 2018 were identified in a national database. Patients were stratified into 2 cohorts: general anesthesia and general anesthesia combined with regional anesthesia. In this analysis, 30-day wound, cardiac, pulmonary, renal, thromboembolic, and sepsis complications, as well mortality, postoperative transfusion, urinary tract infection, extended length of stay, and reoperation were assessed. Bivariate analyses and multivariable logistical regression were performed.ResultsOf 1,084 total patients undergoing TAA, 878 patients (81.0%) had general anesthesia and 206 (19.0%) had general anesthesia combined with regional anesthesia. Following adjustment, there were no increased risk of postoperative complications in the combined general and regional anesthesia group compared to those who only underwent general anesthesia.ConclusionCompared to general anesthesia alone, the addition of regional anesthesia to general anesthesia for TAA is not associated with increased risk of complications in the perioperative period. Level of Evidence: III 相似文献
93.
Premise of the Study
The pygmy forest, a plant community of severely stunted conifers and ericaceous angiosperms, occurs on patches of highly acidic, nutrient‐poor soils along the coast of Northern California, USA. This system is an excellent opportunity to study the effect of severe nutrient deficiency on leaf physiology in a naturally‐occurring ecosystem. In this study, we seek to understand the physiological mechanisms stunting the plants' growth and their implications for whole plant function.Methods
We measured 14 traits pertaining to leaf photosynthetic function or physical structure on seven species. Samples were taken from the pygmy forest community and from conspecifics growing on higher‐nutrient soils, where trees may grow over 30 m tall.Key Results
Pygmy plants of most species maintained similar area‐based photosynthetic and stomatal conductance rates to conspecific controls, but had lower specific leaf area (leaf area divided by dry weight), lower percent nitrogen, and less leaf area relative to xylem growth. Sequoia sempervirens, a species rare in the pygmy forest, had a categorically different response from the more common plants and had remarkably low photosynthetic rates.Conclusions
Pygmy plants were not stunted by low photosynthetic rates on a leaf‐area basis; instead, several species had restricted whole‐plant photosynthesis due to low leaf area production. Pygmy plants of all species showed signs of greater carbon investment in their leaves and higher production of nonphotosynthetic leaf tissue, further contributing to slow growth rates. 相似文献94.
Interdomain salt‐bridges in the Ebola virus protein VP40 and their role in domain association and plasma membrane localization
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Jeevan B. GC Kristen A. Johnson Monica L. Husby Cary T. Frick Bernard S. Gerstman Robert V. Stahelin Prem P. Chapagain 《Protein science : a publication of the Protein Society》2016,25(9):1648-1658
The Ebola virus protein VP40 is a transformer protein that possesses an extraordinary ability to accomplish multiple functions by transforming into various oligomeric conformations. The disengagement of the C‐terminal domain (CTD) from the N‐terminal domain (NTD) is a crucial step in the conformational transformations of VP40 from the dimeric form to the hexameric form or octameric ring structure. Here, we use various molecular dynamics (MD) simulations to investigate the dynamics of the VP40 protein and the roles of interdomain interactions that are important for the domain–domain association and dissociation, and report on experimental results of the behavior of mutant variants of VP40. The MD studies find that various salt‐bridge interactions modulate the VP40 domain dynamics by providing conformational specificity through interdomain interactions. The MD simulations reveal a novel salt‐bridge between D45‐K326 when the CTD participates in a latch‐like interaction with the NTD. The D45‐K326 salt‐bridge interaction is proposed to help domain–domain association, whereas the E76‐K291 interaction is important for stabilizing the closed‐form structure. The effects of the removal of important VP40 salt‐bridges on plasma membrane (PM) localization, VP40 oligomerization, and virus like particle (VLP) budding assays were investigated experimentally by live cell imaging using an EGFP‐tagged VP40 system. It is found that the mutations K291E and D45K show enhanced PM localization but D45K significantly reduced VLP formation. 相似文献
95.
Cloning and characterization of a cDNA from Aspergillus parasiticus encoding an O-methyltransferase involved in aflatoxin biosynthesis. 总被引:7,自引:19,他引:7
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J Yu J W Cary D Bhatnagar T E Cleveland N P Keller F S Chu 《Applied microbiology》1993,59(11):3564-3571
Aflatoxins are polyketide-derived secondary metabolites produced by the fungi Aspergillus flavus and Aspergillus parasiticus. Among the catalytic steps in the aflatoxin biosynthetic pathway, the conversion of sterigmatocystin to O-methylsterigmatocystin and the conversion of dihydrosterigmatocystin to dihydro-O-methylsterigmatocystin are catalyzed by an S-adenosylmethionine-dependent O-methyltransferase. A cDNA library was constructed by using RNA isolated from a 24-h-old culture of wild-type A. parasiticus SRRC 143 and was screened by using polyclonal antiserum raised against a purified 40-kDa O-methyltransferase protein. A clone that harbored a full-length cDNA insert (1,460 bp) containing the 1,254-bp coding region of the gene omt-1 was identified by the antiserum and isolated. The complete cDNA sequence was determined, and the corresponding 418-amino-acid sequence of the native enzyme with a molecular weight of 46,000 was deduced. This 46-kDa native enzyme has a leader sequence of 41 amino acids, and the mature form of the enzyme apparently consists of 377 amino acids and has a molecular weight of 42,000. Direct sequencing of the purified mature enzyme from A. parasiticus SRRC 163 showed that 19 of 22 amino acid residues were identical to the amino acid residues in an internal region of the deduced amino acid sequence of the mature protein. The 1,460-bp omt-1 cDNA was cloned into an Escherichia coli expression system; a Western blot (immunoblot) analysis of crude extracts from this expression system revealed a 51-kDa fusion protein (fused with a 5-kDa beta-galactosidase N-terminal fragment).(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
96.
Queen SE Mears BM Kelly KM Dorsey JL Liao Z Dinoso JB Gama L Adams RJ Zink MC Clements JE Kent SJ Mankowski JL 《Journal of virology》2011,85(17):9167-9175
In response to pressure exerted by major histocompatibility complex (MHC) class I-mediated CD8(+) T cell control, human immunodeficiency virus (HIV) escape mutations often arise in immunodominant epitopes recognized by MHC class I alleles. While the current standard of care for HIV-infected patients is treatment with highly active antiretroviral therapy (HAART), suppression of viral replication in these patients is not absolute and latently infected cells persist as lifelong reservoirs. To determine whether HIV escape from MHC class I-restricted CD8(+) T cell control develops during HAART treatment and then enters latent reservoirs in the periphery and central nervous system (CNS), with the potential to emerge as replication-competent virus, we tracked the longitudinal development of the simian immunodeficiency virus (SIV) Gag escape mutation K165R in HAART-treated SIV-infected pigtailed macaques. Key findings of these studies included: (i) SIV Gag K165R escape mutations emerged in both plasma and cerebrospinal fluid (CSF) during the decaying phase of viremia after HAART initiation before suppression of viral replication, (ii) SIV K165R Gag escape mutations were archived in latent proviral DNA reservoirs, including the brain in animals receiving HAART that suppressed viral replication, and (iii) replication-competent SIV Gag K165R escape mutations were present in the resting CD4(+) T cell reservoir in HAART-treated SIV-infected macaques. Despite early administration of aggressive antiretroviral treatment, HIV immune escape from CD8(+) T cell control can still develop during the decaying phases of viremia and then persist in latent reservoirs, including the brain, with the potential to emerge if HAART therapy is interrupted. 相似文献
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100.
Cary Willard Elsie Wong John F. Hess Che-Kun James Shen Barbara Chapman Allan C. Wilson Carl W. Schmid 《Journal of molecular evolution》1985,22(4):309-315
Summary The DNA base sequences of the entire chimpanzee 1 globin gene and an additional 1 kb of DNA flanking both the human and chimpanzee genes have been determined. Whereas the human 1 gene contains a termination codon in the sixth position, the chimpanzee gene appears to be functional. This finding confirms Proudfoot et al.'s suggestion that the human 1 gene was recently inactivated. Like the corresponding human 1 and 2 genes, the first and second introns of the chimpanzee 1 gene are occupied largely by tandem repeats of short oligonucleotides. These tandem repeats have undergone several rearrangements since the divergence of the human and chimpanzee 1 genes. 相似文献