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At least 1,621 records · Page 90Linked to original sources
PubMed1998

Isolation and characterization of an estrogen binding protein which may integrate the plethora of estrogenic actions in non-reproductive organs.

A putative estrogen receptor (pER) from mouse liver has been characterized. The heterodimer protein (81-84 kDa) consists of two covalently bound subunits (61-67 and 17-27 kDa) with following characteristics: sedimentation constant--4.9 S; IP--4.8; dissociation constant (Kd) for estradiol-17beta binding--0.7 nmol; binding sites--0.746 pmol/mg protein; relative binding affinity--estradiol-17beta--100, estrone--80 and estriol--30; specificity--does not bind, other natural steroids, synthetic estrogens, antiestrogens and bioflavonoids. Importantly, immunosuppressants, neuroleptic and carcinogens influence 3H-estradiol-17beta binding to pER. Interestingly, pER is a serine phosphatase and this may have relevancy to estrogen action in Alzheimer's disease. The polyclonal anti-pER antibody does not react with estrogen receptors (ER). ER antibody does not react with pER. Remarkably, anti-pER antibody reacts with calcineurin, a brain phosphatase and anti-calcineurin antibody reacts with pER. Immunohistochemical analyses showed that pER is undetectable in reproductive organs (except ovary). It is localized on the plasma or the nuclear membranes in some, in cytoplasm and/or nucleus in other cells of non-reproductive organs (skeletal, neural, vascular, hair and retina), and in tumors (mammary, endometrial and prostate cancers, and prostatic hyperplasia). The information presented justifies the proposition that pER may mediate the estrogenic actions in non-reproductive organs.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1996

Characterization of a polyubiquitin gene in T. thermophila and of ubiquitin gene expression during sexual reproduction and under stress conditions.

A 5-unit polyubiquitin gene, TTU3, was isolated from a T. thermophila genomic library and sequenced. This gene presents an extra triplet coding for Phe, a AGAGA motif and a putative HSE element in its 5'-non-coding region. The ubiquitin gene expression in this ciliate was investigated by Northern blot hybridization in conjugating cells or cells under stress conditions. Exponentially growing cells express two ubiquitin mRNAs of 0.75 and 1.8 kb and a new species of 1.4 kb is induced under hyperthermic stress. During sexual reproduction of the cells (conjugation) the 1.8-kb mRNA is still transcribed whereas the steady-state population of the 0.75 mRNA transcripts is strongly diminished. Southern blot analysis suggests that ubiquitin in T. thermophila constitutes a large family of about ten members.

Amino Acid Sequence↗
PubMed2003

A test of the endogenous and exogenous selection hypotheses for the maintenance of a narrow avian hybrid zone.

The contributions of genetic and environmental factors to differential reproductive success across hybrid zones have rarely been tested. Here, we report a manipulative experiment that simultaneously tested endogenous (genetic-based) and exogenous (environmental-based) selection within a hybrid zone. We transplanted mated pairs of two chickadee species (Poecile atricapilla and P. carolinensis) and their hybrids into isolated woodlots within their hybrid zone and monitored their reproductive success. Although clutch sizes were similar, based on an estimate of the genetic compatibility of a pair, hybrid pairs produced fewer nestlings and fledglings than did pairs of either parental species. According to a linear model generated from the data, a pure pair of either parental species would be expected to produce 1.91-2.48 times more fledglings per nesting attempt, respectively, than the average or least compatible pair in the experiment. Our result of decreased reproduction for hybrid pairs relative to parental species pairs within same environment (the hybrid zone in this experiment) support the endogenous selection hypothesis for maintenance of this hybrid zone. Because the experiment was conducted entirely within the hybrid zone (i.e., the same environment for parental and hybrid pairings), our data do not support the exogenous selection hypothesis as it predicts either all pairings doing poorly or the hybrid pairs more successful than the parental pairs.

Animals↗
PubMedDate not supplied

Ultrastructural pathogenesis of the PRRS virus.

Porcine Reproductive and Respiratory Syndrome Virus (PRRSV) was first isolated in swine alveolar macrophages (SAMs) and has subsequently been reported to replicate in other cell lines. Entry of the virus inside the cell takes place by receptor-mediated endocytosis. Following the entry of the virus into the cell, several not completely understood changes take place. PRRSV has been reported to be an apoptotic-inductor virus both in vivo and in vitro. Interestingly, it has been suggested that PRRSV-induced apoptosis occurs in cells other than those in which PRRSV replicates by a bystander mechanism. In this paper the ultrastructural pathogenesis of PRRSV will be reviewed.

Animals↗
PubMedDate not supplied

[Sensitivity of influenza A/H5 viruses isolated from wild birds on the territory of Russia to arbidol in the cultured MDCK cells].

The effect of the antiviral drug arbidol on the reproduction of avian influenza A/H5 viruses was studied in in vitro experiments. The strains were isolated from the wild birds of Eastern Siberia and they were closely related to the 1997-2000 viruses from South-Eastern Asia. Arbidol was shown to exert a selective inhibiting effect on the reproduction of these viruses in the MDCH cell cultures.

Animals↗
PubMed1996

Diversification of C-function activity in maize flower development.

The Arabidopsis gene AGAMOUS is required for male and female reproductive organ development and for floral determinacy. Reverse genetics allowed the isolation of a transposon-induced mutation in ZAG1, the maize homolog of AGAMOUS. ZAG1 mutants exhibited a loss of determinacy, but the identity of reproductive organs was largely unaffected. This suggested a redundancy in maize sex organ specification that led to the identification and cloning of a second AGAMOUS homolog, ZMM2, that has a pattern of expression distinct from that of ZAG1. C-function organ identity in maize (as defined by the A, B, C model of floral organ development) may therefore be orchestrated by two closely related genes, ZAG1 and ZMM2, with overlapping but nonidentical activities.

Alleles↗
PubMed1990

Observations on the reproductive biology of Onchocerca volvulus.

This study compiles observations on the reproductive capacity of O. volvulus. Adult parasites enzymatically isolated from excised onchocercomata of untreated and chemotherapeutically treated patients, and from inhabitants living in areas with long vector control, were investigated to assess their fecundity. Changes of microfilaria development in utero and microfilaria release were assessed or estimated after treatment of patients with micro-filaricidal drugs that interfered with the development of intra-uterine stages. Intra-uterine production of microfilariae: After treatment of patients with ivermectin a daily development of 2500 to 4000 uterine microfilariae per female worm was observed. Actual output of microfilariae: Microfilariae left actively the female worms. The daily microfilaria release in vivo was 700 to 900 microfilariae, assessed after treatment of patients with mebendazole. In vitro most worms isolated from untreated patients shed between 500 to 1500 microfilariae per day.-The microfilarial load of 56 adult patients calculated from microfilarial skin counts was 12 million on the average. Taken for granted a mean life span of a microfilaria of 1.0 to 1.5 years, 22 to 47 female worms per patient would suffice to maintain this microfilarial load on a constant level. Excision of all palpable nodules showed a geometric mean of 15.9 female worms in these patients. It is suggested that factors intrinsic in the host and the adult worms partially operate together to regulate and maintain a stable microfilarial density.

Animals↗
PubMed1995

[Varying sensitivity to acyclovir of different years' clinical isolates of herpes simplex virus].

The population of types I and 2 herpes simplex viruses (HSV) to be studied consisted mainly of Acyclovir-sensitive strains. In some cases Acyclovir-resistant HSV strains were detected. The phenotypic profile of the Acyclovir-resistant strains were shown to have low reproduction rates in tissue cultures. Their antigenic character was similar to that of reference strains. Several phenotypic variants concurrently isolated from the same patient differ in their reproductive properties, antigenic characteristics, and sensitivity to Acyclovir. It is expedient to examine HSV isolates from patients for their sensitivity to chemicals used in clinical practice. This will allow patients with herpes infection to be treated on an individual basis.

Acyclovir↗
PubMed2005

[Sensitivity of various influenza virus strains to arbidol. Influence of arbidol combination with different antiviral drugs on reproduction of influenza virus A].

AIM: To study antiviral activity of arbidol in relation to various antigenic subtypes of influenza virus isolated from humans; efficacy of arbidol action in combination with adamantanic antiviral drugs, ribavirin and ribamidil on reproduction of influenza virus A (IVA) in cell culture. MATERIAL AND METHODS: The activity of the drugs against viral reproduction was assessed by inhibition of viral antigens expression detected in virus-infected cells using enzyme immunoassay (EIA). RESULTS: Arbidol is not inferior to adamantanic drugs, neuraminidase inhibitors, ribavirin and ribamidil by its inhibiting activity in relation to influenza viruses A and B. Arbidol inhibits reproduction of human IVA antigenic strains H1N1, H2N2, H3N2 and remantadin-sensitive and remantadin-resistant strains of influenza virus. Arbidol inhibits reproduction of pathogenic for humans strains of avian influenza virus H5N1 and H9N2, strains H6N1 and H9N2 having internal genes common with H5N1 and H9N2. The inhibiting activity of arbidolin on cell culture viral reproduction enhanced if arbidol was used in combination with amantadine, remantadin, ribavirin and ribamidil. CONCLUSION: Arbidol has a wide spectrum antiviral activity and inhibits reproduction of various antigenic subtypes and remantadin-resistent human IVA, avian viruses H5N1 and H9N2, influenza viruses B and C.

Amantadine↗
PubMed2005

Phenotypic plasticity of host-parasite interactions in response to the route of infection.

The microsporidium Octosporea bayeri can infect its host, the planktonic crustacean Daphnia magna, vertically and horizontally. The two routes differ greatly in the way the parasite leaves the harbouring host (transmission) and in the way it enters a new, susceptible host (infection). Infections resulting from each route may thus vary in the way they affect host and parasite life-histories and, subsequently, host and parasite fitness. We conducted a life-table experiment to compare D. magna infected with O. bayeri either horizontally or vertically, using three different parasite isolates. Both the infection route and the parasite isolate had significant effects on host life-history. Hosts matured at different ages depending on the parasite isolate, and at a size that varied with infection route. The frequency of host sterility and the host's life-time reproductive success were affected by both the infection route and the parasite isolate. The infection route also affected parasite life-history. The production of parasite spores was much higher in vertically than in horizontally infected hosts. We found a trade-off between the production of spores (the parasite's horizontal fitness component) and the production of infected host offspring (the parasite's vertical fitness component). This study shows that hosts and parasites can react plastically to different routes of infection, suggesting that ecological factors that may influence the relative importance of horizontal and vertical transmission can shape the evolution of host and parasite life histories, and, consequently, the evolution of virulence.

Age Factors↗
PubMed1991

Non-genetic mothers and their own children: infertility and IVF donor birth.

Over the 1980s in Western societies which have used new reproductive technologies, there has been intense argumentation about connected philosophical, ethical and economic issues. This research on I.V.F. donor egg (i.e. 'non-genetic') motherhood is based on qualitative data from partial life histories of twelve women having children by this technology through a Melbourne infertility programme. Methodology, interpretation, and discussion place it within both critical social and feminist personal identity theoretical frameworks. None of the respondent women but all except one of their respective partners are the biological parents of a total of ten children already born at the data collection stage, and in three well-established pregnancies. Two-thirds of the respondents used 'unknown' donor ova. 'Known' donors were typically the recipients' sisters. Many of these Australian births represent world 'firsts' in medical technical applications. In biographical accounts, the focus was on experiences of social pressure towards parenthood, of infertility and medical treatment, and attitudes of openness or secrecy about using donated ova. While socially and technologically acquired parenthood added a highly-desired dimension to their social identities, a sense of loss appeared to persist in most of the women's personal identities. Where a policy of secrecy towards relatives and friends about use of reproductive technology and gamete donation was maintained, this loss was reinforced by a feeling of social isolation.

Australia↗
PubMed1967

Strain of mycoplasma associated with human reproductive failure.

A strain of mycoplasma not previously described has been isolated from the chorion, decidua, and amnion of a patient who sustained a spontaneous abortion during the middle trimester. The fetal membranes exhibited an inflammatory reaction, but no evidence of other infectious agents, bacterial or viral, was noted. The T strain identified is not a classical mycoplasma; it differs in growth and nutritional requirements from the T strains previously characterized.

Abortion, Spontaneous↗
PubMed1970

Sexual reproduction in Candida lipolytica.

Candida lipolytica is a rather common yeast isolated more frequently from substrates containing lipids or proteins, such as dairy products, than from substrates rich in sugars. This species assimilates hydrocarbons and is currently being studied for its potential to convert petroleum into yeast cells for use in feeds and foods. We have found C. lipolytica to exist in nature primarily in the heterothallic haploid state. When appropriate strains of opposite sex are mixed on a suitable sporulation medium, conjugation occurs followed by the production of ascospores. Since heterothallism permits laboratory control of hybridization, this characteristic of C. lipolytica enhances the possibility of im proving its strains for technological uses.

Candida↗
PubMed1999

The changing nature of adolescence in the Kassena-Nankana District of northern Ghana.

This study reports the results of a primarily qualitative investigation of adolescent reproductive behavior in the Kassena-Nankana District, an isolated rural area in northern Ghana, where traditional patterns of marriage, family formation, and social organization persist. The study is based on in-depth interviews and focus-group discussions with adolescents, parents, chiefs, traditional leaders, youth leaders, and health workers, supplemented by quantitative data from the 1996 wave of a panel survey of women of reproductive age conducted by the Navrongo Health Research Centre. The social environment that adolescent boys and girls in the Kassena-Nankana District encounter and its links to reproductive behavior are described. The principal question is whether even in this remote rural area, the social environment has been altered in ways that have undermined traditional sexual and reproductive patterns. The survey data indicate a considerable increase in girls' education and the beginning of a decline in the incidence of early marriage. The qualitative data suggest that social institutions, systems, and practices such as female circumcision that previously structured the lives of adolescent boys and girls have eroded, leading to an apparent increase in premarital sexual activity.

Adolescent↗
PubMed2002

Insecticide resistance enhances male reproductive success in a beetle.

Malathion-specific resistance in the red flour beetle, Tribolium castaneum, is widespread and stable in natural populations even in the absence of pesticide exposure. To understand this stability, both resistant and susceptible males were placed in competition for susceptible female fertilization. Females were then isolated and their progeny was tested for malathion susceptibility. Male reproductive success was estimated for populations originating from different geographic areas and for isogenic strains. In most cases, resistant males had a greater reproductive success rate than susceptibles. The results suggest that male reproductive success is not traded against the selection for malathion resistance, even resistant individuals are at an advantage for this fitness trait. This absence of fitness cost may be the result of postselection of (1) modifier gene which ameliorate the fitness of resistant individuals or (2) nondeleterious resistance gene. Resistant phenotype superiority could be due to increased male mating success, improved ability of resistant males in sperm competition, female mate choice, and/or cryptic female choice of resistance gene(s). The effect of male phenotypic frequency on male reproductive success was also examined. We observed that male fertilization success is frequency dependent and inversely related to their frequency. However, this "rare male" advantage did not counteract the superiority of the resistant males.

Animals↗
PubMed2000

Role of activins in the male reproductive tract.

The search for gonadal proteins that regulate pituitary FSH led to the isolation of inhibins and activins. As members of the transforming growth factor beta (TGFbeta) superfamily of growth and differentiation factors, these proteins have been shown subsequently to affect a range of tissues and systems beyond their role in reproduction. Studies on the expression and synthesis of activins in the male reproductive tract have localized these proteins in the testis, epididymis and prostate. In general, activins regulate cell proliferation and, consequently, the expression and localization of activin subunit mRNAs and proteins within these organs must be discrete. Activin ligand bioactivity is dependent on the presence of the appropriate receptors and signalling systems, but activin ligand formation or access to receptors is regulated by the formation of inhibins or by activin-binding proteins such as follistatin. This review examines the evidence that the capacity to synthesize activins and to regulate activin bioactivity resides in the cells of the male reproductive tract. It is concluded that activins exert their effects through local (autocrine or paracrine) mechanisms, rather than through endocrine systems. The interplay between the inhibins or follistatins provides a degree of regulation of activin bioactivity before ligand signalling events. The challenge for the future is to determine whether there is any difference between the action of individual activin ligands or whether these proteins are functionally redundant, indicating that compensatory mechanisms are essential for male reproductive tract function.

Activins↗
PubMed1992

Experimental reproduction of swine infertility and respiratory syndrome in pregnant sows.

The purpose of this study was to experimentally reproduce swine infertility and respiratory syndrome (SIRS). Six multiparous sows were intranasally inoculated at 93 days of gestation with lung homogenates from clinically affected pigs, and 3 additional sows were similarly inoculated with a virus isolated in cell culture from the lung homogenate (SIRS virus, isolate ATCC VR-2332). Inoculated sows developed transient anorexia, farrowed up to 7 days prematurely, and delivered a mean of 5.8 live pigs and 6.0 dead fetuses/litter. Clinical signs of disease were not observed in 3 sham-inoculated control sows that delivered a mean of 12.7 live pigs and 0.3 stillborn fetuses/litter. The SIRS virus was isolated from 50 of 76 live-born and stillborn fetuses from the 9 infected litters. Virus was not isolated from 26 autolyzed fetuses or 15 control pigs. Six of 9 inoculated sows developed neutralizing antibodies to SIRS virus. The reproductive effects found in these experiments were identical to those found in field cases. On the basis of our findings, virus isolate ATCC VR-2332 causes the reproductive failure associated with SIRS.

Animals↗