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Biomedical subjects

D L Russell

Publications and source records attributed to D L Russell.

31 records · Page 2Linked to original sources
PubMed1993

Binding sites for interferons on ovine and human endometrial membranes.

In the ewe, the major product of the preimplantation blastocyst is ovine trophoblast protein-1 (oTP-1), which is now classified as an omega-interferon (IFN). Receptors for IFN are present on sheep endometrium and vary cyclically, presumably modified by the actions of ovarian steroids. This study examined whether or not IFN receptors were present on human endometrium at any stage during the menstrual cycle. In addition, the steroid dependence of ovine endometrial IFN receptors was determined. Specific binding of 125I-labelled IFN (125I-IFN) to ovine endometrial membranes was substantially higher than binding to membranes derived from bovine spleen, human placenta or pooled human endometrium (relative specific binding 100:33:36:20). Human endometrial membrane preparations from proliferative-phase tissue showed very little specific binding (mean 0.8 +/- 0.3%, n = 4) in contrast to luteal-phase endometrium (2.1 +/- 0.3%, n = 8). Treatment of ovariectomized ewes with oestradiol-17 beta (E) resulted in significantly increased binding (117 +/- 7%) of 125I-IFN to endometrial tissues compared with tissue from ovariectomized (OvX, 75 +/- 7%), progesterone (P)-treated (69 +/- 7%), or (E + P)-treated (81 +/- 8%) groups (P < 0.05); all were compared with binding to pooled ovine luteal-phase tissue, 100%. There were no differences between the other three groups. Scatchard analysis showed binding affinity of the same order for the sheep and human receptors (Kd = 10(-10) mol L-1) but binding capacity was considerably lower for human (6.0 fmol mg-1) than for sheep (47-123 fmol mg-1) endometrium.(ABSTRACT TRUNCATED AT 250 WORDS)

Amnion↗
PubMed1991

Peripheral concentrations of immunoreactive inhibin during pregnancy and parturition in the ewe.

The aim of this study was to measure the peripheral concentrations of immunoreactive inhibin (ir-inhibin) and progesterone (P) during pregnancy and parturition in the ewe and to relate the concentrations of ir-inhibin to P and to the number and sex of the fetuses. P increased across pregnancy with higher levels in ewes with 2 fetuses (n = 5) than in those with 1 fetus (n = 6), and concentrations falling before birth. ir-Inhibin concentrations were relatively stable during the first 40 days of pregnancy for example (Day 20, 34.7 +/- 2.9 pmol L-1; mean +/- s.e.m., n = 11). After Day 40, inhibin fell in all ewes to reach less than or equal to 2.5 pmol L-1 after Day 80 (mean on Day 103, 6.3 +/- 1.2 pmol L-1), and remained low until 2 days before parturition when concentrations rose sharply, peaking at or around the day of birth in all ewes (21.5 +/- 2.1 pmol L-1). Thereafter, ir-inhibin fell and remained low or undetectable for up to 10 days in the six ewes still being sampled. ir-Inhibin concentrations in ewes carrying one (n = 6), two (n = 5) or three fetuses (n = 1) did not differ at any stage of pregnancy examined. The sex of the fetus did not appear to influence the peripheral concentrations of ir-inhibin in the ewe.

Analysis of Variance↗
PubMed1989

Sindbis virus mutations which coordinately affect glycoprotein processing, penetration, and virulence in mice.

Rapid penetration of baby hamster kidney cells was used as a selective pressure for the isolation of pathogenesis mutants of the S.A.AR86 strain of Sindbis virus. Unlike most Sindbis virus strains, S.A.AR86 is virulent in adult as well as neonatal mice. Two classes of mutants were defined. One class was attenuated in adult mice inoculated intracerebrally as well as in neonatal mice inoculated either intracerebrally or subcutaneously. Sequence analysis of the glycoprotein genes of the parent virus and three such mutant strains revealed a single point mutation which resulted in an amino acid change at position 1 in the E2 glycoprotein. The change from a serine in S.A.AR86 to an asparagine in the mutants created a new site for N-linked glycosylation which appeared to be utilized. This mutation did not retard release of infectious particles; however, mutant virions contained the E2 precursor protein (PE2) rather than the E2 glycoprotein itself. The mutants also lost the ability to bind two E2-specific monoclonal antibodies, R6 and R13. A second class of mutants was attenuated in neonatal mice upon subcutaneous inoculation but remained virulent in adults and in neonates when inoculated intracerebrally. Sequence analysis of three such strains revealed the substitution of an arginine residue for a serine at position 114 in the E2 glycoprotein. Reactivity with monoclonal antibodies R6 and R13 was reduced, yet members of this mutant class were more susceptible than S.A.AR86 to neutralization by these antibodies.

Amino Acid Sequence↗
PubMed1986

Two-Dimensional Polyacrylamide Gel Analysis of Plodia interpunctella Granulosis Virus.

The structural polypeptides of purified Plodia interpunctella granulosis virus were analyzed by three different two-dimensional gel systems. Isoelectric focusing followed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis allowed resolution of 53 acidic polypeptides in the enveloped nucleocapsid of the virus ranging in molecular weight from 97,300 to 8,000. Nine of these polypeptides were shown to be glycoproteins by the technique of radiolabeled lectin blotting. Separation of the granulin in this system allowed resolution of five species, all of which have identical tryptic peptide maps. This matrix protein was demonstrated to be a phosphoglycoprotein by radiolabeled lectin blotting and acid phosphatase dephosphorylation. Nonequilibrium pH gel electrophoresis followed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis allowed resolution of the major basic protein of the virus, VP12, from a more acidic protein of the same molecular weight. Tryptic peptide analysis demonstrated that these two proteins were indeed different and acid urea gels followed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis allowed localization of the acidic protein to the envelope and the basic protein to the nucleocapsid of the virus. Finally, probing of the separated envelope nucleocapsid proteins in both the isoelectric focusing and nonequilibrium pH gel electrophoresis two-dimensional systems after transfer to nitrocellulose with iodinated, purified viral proteins allowed further insight into reactions which may be important in the maintenance of the virion structure.

Journal Article↗
PubMed1985

Glycosylation of purified enveloped nucleocapsids of the granulosis virus infecting Plodia interpunctella as determined by lectin binding.

Using various iodinated plant lectins and a sensitive in vitro lectin binding procedure in which the radiolabeled lectins are applied directly to viral proteins on nitrocellulose sheets transferred from sodium dodecyl sulfate-polyacrylamide gels (Bartles and Hubbard, 1984; Glass et al., 1981), the proteins of the granulosis virus infecting Plodia interpunctella were probed for carbohydrate moieties. Six proteins (Mr 39 700, 31 000, 29 900, 26 300, 17 800 and 12 600) could be detected using a probe for alpha-D-N-acetylgalactosamine. Three proteins were also detectable with the probe specific for alpha-L-fucose (Mr 44 900, 31 000 and 17 800). One protein (Mr 17 800) was detected with the probe for sialic acid.

Animals↗
PubMed1980

Suppressors of mutations in the bacteriophage T4 gene coding for both RNA ligase and tail fiber attachment activities.

The protein product of T4 gene 63 catalyzes both the attachment of tail fibers to fiberless phage particles and the ligation of single-stranded RNA (Snopek at al., Proc. Natl. Acad. Sci. U.S.A. 74:3355-3359, 1977). To investigate whether the gene 63 product has a role in nucleotide metabolism, we isolated false revertants of amM69 in gene 63. We screened for revertants that could grow at 30 degrees C but not at 43 degrees C on Escherichia coli OK305 when nucleotides were limiting. These false revertants contained the original mutation in gene 63 and new suppressor mutations. Some of these suppressor mutations caused temperature sensitivity by themselves, allowing single mutants carrying the suppressor to be recognized and isolated. The results of mapping and complementation studies indicated that most of these ts suppressors were in the t gene (lysis), one was in gene 5 (baseplate), and one was in gene 18 (sheath). The mutation in gene 18, tsDH638, suppressed three different amber mutations in gene 63 but did not suppress amber mutations in several other genes. None of the suppressors that were characterized were in genes with known functions in nucleotide metabolism. However, an intriguing property of these false revertants was that they were very sensitive to hydroxyurea, an inhibitor of nucleotide metabolism.

Chromosome Mapping↗
PubMedDate not supplied

Ovulation: a multi-gene, multi-step process.

The luteinizing hormone (LH) surge initiates a cascade of proteolytic events that control ovulation. One of the genes induced by LH is the progesterone receptor (PR). Because mice with a mutant PR gene (PRKO) fail to ovulate and are infertile, we have used them as a model in which to determine PR target genes that might mediate the ovulatory process. The matrix metalloproteinases (MMPs: MMP2, MMP9, and MMP13) appear to be expressed in ovaries of PRKO mice in a manner similar to that in their wild-type littermates. However, the expression of two other types of proteases, cathepsin L (a member of the papain family) and ADAMTS-1 (A Disintegrin And Metalloproteinase with Thrombospondin-like motifs), are selectively induced in granulosa cells of preovulatory follicles by the LH surge. Maximal levels of these proteases are observed at 12-16 h after an LH surge, the time of ovulation. Furthermore, mRNAs encoding cathepsin L and ADAMTS-1 are reduced in the PRKO mice compared to their wild-type littermates. These novel observations indicate that these two proteases regulate some key step(s) controlling ovulation.

ADAM Proteins↗