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Molecular cloning and characterization of a sym plasmid locus that regulates cultivar-specific nodulation of soybean by Rhizobium fredii USDA257 (1993)

Meinhardt, L. W. ; Krishnan, H. B. ; Balatti, P. A. ; [et al.]

Oxford, UK : Blackwell Publishing Ltd

Molecular microbiology 9 (1993), S. 0

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ISSN: 1365-2958

Source: Blackwell Publishing Journal Backfiles 1879-2005

Topics: Biology , Medicine

Notes: Rhizobium fredii strain USDA257 produces nitrogen-fixing nodules on primitive soybean cultivars such as Peking but fails to nodulate agronomically improved cultivars such as McCall. Transposonmutant 257DH4 has two new phenotypes: it nodulates McCall, and its ability to do so is sensitive to the presence of parental strain U5DA257, i.e. it is subject to competitive nodulation blocking. We have isolated a cosmid containing DNA that corresponds to the site of transposon insertion in 257DH4 and have localized Tn5 on an 8.0 kb EcoRI fragment. The 5596 bp DNA sequence that surrounds the insertion site contains seven open reading frames. Five of these, designated nolBTU, ORF4, and nolV, are closely spaced and of the same polarity. nolWand nolX are of the opposite polarity. The initiation codon for nolW lies 155bp upstream from that of nolB, and it is separated from nolXby 281 bp. The predicted NolT and NolW proteins have putative membrane-spanning regions. The N-terminus of the hypothetical NolW protein also has limited homology to NodH of Rhizobium meliloti, but none of the deduced protein sequences has significant homology to known nodulation gene products. Site-directed mutagenesis with mudll1734 confirms that inactivation of nolB, nolT, nolU, nolV, nolW, or nolX extends host range for nodulation to McCall soybean. This phenotype could not be genetically dissected from sensitivity to competitive nodulation blocking. Expression of nolBTU anti nolX is induced as much as 30-fold by flavonoid signal molecules, even though these genes lack nod-box promoters. Histochemical staining of McCall roots inoculated with nolB–, nolU–, or nolX–lacZ fusions verifies that these genes are expressed continuously from preinfection to the stage of the functional nodule. Although a nolU–ORF4–nolV clone hybridizes to a single 8.0 kb EcoRI fragment from 10 strains of R. fredii and broad-host-range Rhizobium sp. NGR234, hybridizing sequences are not detectable in other rhizobia.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1111/j.1365-2958.1993.tb01665.x

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Is there an optimal time for the first cyclosporin dose in renal transplantation? (1993)

Griffin, P. J. A. ; Moore, R. H. ; Krishnan, H. ; [et al.]

Springer

Transplant international 6 (1993), S. 223-225

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ISSN: 1432-2277

Keywords: Cyclosporin, renal transplantation, time first dose ; Renal transplantation, cyclosporin, time first dose ; Time first dose, cyclosporin, renal transplantation

Source: Springer Online Journal Archives 1860-2000

Topics: Medicine

Notes: Abstract It is customary for patients undergoing kidney transplantation to receive their first dose of cyclosporin either just before or during the transplant operation. This ensures the early establishment of good levels of immuno-suppression but might depress early graft function and contribute towards the development of acute tubular necrosis. In a controlled clinical trial, we have studied the effects of withholding cyclosporin for 12 h in patients undergoing cadaveric renal transplantation. Consecutive adult recipients of a cadaveric renal transplant were randomised to receive their first dose of cyclosporin (10 mg/kg p. o.) 6 h prior to transplant surgery or 12 h afterwards. All patients received azathioprine (1.5 mg/kg i.v.) and methylprednisolone (0.5 gi.v) in addition during surgery. From the 2nd day onwards both groups were treated with an identical triple immunosuppressive regimen. The 27 patients who received their first dose of cyclosporin post-operatively had significantly better immediate and subsequent function than did the 26 patients who received their cyclosporin at the time of surgery. The delayed dosing was associated with improved graft survival and no increase in the frequency of rejection episodes. This regimen is recommended for all patients receiving triple therapy.