The phylogeny of prokaryotes   总被引：92，自引：0，他引：92  

G E Fox  E Stackebrandt  R B Hespell  J Gibson  J Maniloff  T A Dyer  R S Wolfe  W E Balch  R S Tanner  L J Magrum  L B Zablen  R Blakemore  R Gupta  L Bonen  B J Lewis  D A Stahl  K R Luehrsen  K N Chen  C R Woese 《Science (New York, N.Y.)》1980,209(4455):457-463

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Inorganic nitrogen compounds in ocean stagnation and nutrient resupply     

Sen Gupta R 《Science (New York, N.Y.)》1968,160(3830):884-885

The interrelations and time-dependence of nitrate, nitrite, and ammonia in a deep basin of the Baltic Sea yield a measurement of stagnation history and may provide a means of prediction of resupply of nutrients to the upper productive layers.  相似文献   

Mercury-Based Cuprate High-Transition Temperature Grain-Boundary Junctions and SQUIDs Operating Above 110 Kelvin     

Gupta A  Sun JZ  Tsuei CC 《Science (New York, N.Y.)》1994,265(5175):1075-1077

The superconducting transport characteristics of HgBa(2) CaCu(2)O(6+delta) (Hg-1212) films and grain-boundary junctions grown on (100)-oriented SrTiO(3) bicrystal substrates have been investigated. The films exhibit a zero-resistance temperature of approximately 120 kelvin and sustain large critical current densities, with values as high as 10(6) amperes per square centimeter at around 100 kelvin. On the other hand, the grain boundaries behave as weak links, with substantially lower critical currents, as is observed for other cuprate superconductors. A reduction of three orders of magnitude in critical current was observed for transport across a 36.8 degrees grain boundary. The current-voltage characteristics of bridges across such a grain boundary show weak-link behavior qualitatively resembling that of a resistively shunted junction. Single-level direct-current superconducting quantum interference devices (SQUIDs) have been fabricated with such bicrystal junctions. These SQUIDs show clear periodic voltage modulations when subjected to applied magnetic fields. The SQUIDs operate at temperatures as high as 111.8 kelvin, which makes them attractive for operation in portable sensors and devices that utilize nonconventional cooling methods.  相似文献   

Sequence of the 16S Ribosomal RNA from Halobacterium volcanii, an Archaebacterium     

Gupta R  Lanter JM  Woese CR 《Science (New York, N.Y.)》1983,221(4611):656-659

The sequence of the 16S ribosomal RNA (rRNA) from the archaebacterium Halobacterium volcanii has been determined by DNA sequencing methods. The archaebacterial rRNA is similar to its eubacterial counterpart in secondary structure. Although it is closer in sequence to the eubacterial 16S rRNA than to the eukaryotic 16S-like rRNA, the H. volcanii sequence also shows certain points of specific similarity to its eukaryotic counterpart. Since the H. volcanii sequence is closer to both the eubacterial and the eukaryotic sequences than these two are to one another, it follows that the archaebacterial sequence resembles their common ancestral sequence more closely than does either of the other two versions.  相似文献   

Induction of immune responses in cattle with a DNA vaccine encoding glycoprotein C of bovine herpesvirus-1     

Gupta PK  Saini M  Gupta LK  Rao VD  Bandyopadhyay SK  Butchaiah G  Garg GK  Garg SK 《Veterinary microbiology》2001,78(4):293-305

A DNA vaccine expressing glycoprotein C (gC) of bovine herpesvirus-1 (BHV-1) was evaluated for inducing immunity in bovines. The plasmid encoding gC of BHV-1 was injected six times intramuscularly or intradermally into calves at monthly intervals. After immunization by both routes neutralizing antibody and lymphoproliferative responses developed. The responses in the intradermally immunized calves were better than those in calves immunized intramuscularly. However, the intradermal (i.d.) route was found to be less efficacious when protection against BHV-1 challenge was compared. Following intranasal BHV-1 challenge, all immunized calves demonstrated a rise in IgG antibody titre on day 3, indicating an anamnestic response. The control non-immunized calf developed a neutralizing antibody response on day 7 post-challenge. The immunized calves showed a slight rise in temperature and mild clinical symptoms after challenge. The intramuscularly immunized calves showed earlier clearance of challenge virus compared with intradermally immunized calves. These results indicate that DNA immunization with gC could induce neutralizing antibody and lymphoproliferative responses with BHV-1 responsive memory B cells in bovines. However, the immunity developed was not sufficient to protect calves completely from BHV-1 challenge.  相似文献   

Subchronic toxicity study of urea molasses mineral block in kids     

Roy A  Tiwari SP  Kumari K  Gendley MK  Gupta R 《Veterinary research communications》2009,33(2):183-190

A study was conducted on twenty indigenous goat kids allocated into two different groups. All animals were offered ad libitum rice straw and berseem hay (40:60). Group I (T₁) was fed concentrate mixture (100 g/d). Group II (T₂) was supplemented with urea molasses mineral block (200 g/d). The experiment lasted for 90 days. There was significant decrease in serum sodium (60.68 mEq/L), increase in serum potassium (34.50 mEq/L) and increased activity of AST (340.42 U/L) and ALT (164.96 U/L) was observed in kids of group T₂ in comparison to the controls (T₁). On histopathological examination mild degenerative changes in kidney of group T₂ with congestion in intertubular vessel, granular cytoplasm of the epithelial cells in PCT and DCT, necrosis and swelling of the epithelial cells, congestion of vessels and cloudy swelling was observed in PCT and DCT. Albuminious mass was also present in tubule. On histopathological observation of liver of kid of group T₂ oedema in liver parenchyma and proliferation of fibrious tissue in periportal area was observed.  相似文献   

Effect of Transgene Introduction and Recloning on Efficiency of Porcine Transgenic Cloned Embryo Production In Vitro     

SJ Uhm  MK Gupta  ZC Das  JH Kim  C Park  T Kim  HT Lee 《Reproduction in domestic animals》2009,44(1):106-115

Retrovirus-mediated exogenous gene transfection of somatic cells is an efficient method to produce transgenic embryos by somatic cell nuclear transfer (SCNT). This study evaluated whether efficiency of transgenic embryos production, by SCNT using fibroblast cells transfected by retrovirus vector, is influenced by the introduced transgene and whether recloning could further improve its efficiency. Transgenic cloned embryos were produced by SCNT of porcine foetal fibroblast cells transfected by either LNβ-Z or LNβ-enhanced green fluorescent protein (EGFP) retrovirus vector and evaluated for their developmental ability in vitro . Blastomeres from four-cell stage porcine embryos, produced by SCNT of foetal fibroblast cells transfected with LNβ-EGFP retroviral vector, were subsequently recloned into enucleated metaphase II oocytes and evaluated for changes in chromatin configuration, in vitro embryo development and gene expression. Analysis of results showed that cleavage and blastocyst rates of porcine SCNT embryos, using LacZ (53.6 ± 6.4%; 12.0 ± 5.7%) or EGFP (57.5 ± 6.3%; 10.1 ± 4.1%) transfected fibroblasts, did not differ (p > 0.05) from those of non-transfected controls (60.9 ± 8.2%; 12.3 ± 4.0%). Recloning of blastomeres did not further improve the in vitro development rate. Interestingly, the nuclei of blastomere underwent slower remodelling process than somatic cell nuclei. Both cloned and recloned embryos showed 100% transgene expression and there were no evidence of mosaicism. In conclusion, our data shows that the efficiency of transgenic cloned embryos production by SCNT of somatic cells transfected with replication-defective retrovirus vector is not influenced by the transgene introduction into donor cells and recloning of four-cell stage blastomere could not further improve its efficiency.  相似文献   

Counting the Costs: Economic Growth and Environmental Change in Thailand,edited by J. Rigg. 1995. Institute of Southeast Asian Studies,Singapore, ISBN 981-3055-08-1 (paperback), S$49.50/US$36.50, xxi+267 pp.     

A. Gupta 《Land Degradation \u0026amp; Development》1999,10(6):593-594

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