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PubMed1977

Isolation of nematode inhibitor from hemolymph of the snail, Helix aspersa.

Hemolymph plasma of the snail Helix aspersa which inhibits maturation and reproduction of its mantle cavity-inhabiting nematode, Rhabditis maupasi, was separated biochemically for the active proteinaceous component. Isolation of the active inhibitor was performed using ion-exchange chromatography in combination with subsequent gel filtration. The isolated peaks were bio-assayed in vitro on nematode larvae. The fractions harboring inhibitory protein suppressed larval growth and adult reproduction in vitro. The isolated fraction was purified by gel filtration and characterized on the basis of a single band on starch zone electrophoresis and positive reaction only with folin-phenol reagent.

Animals↗
PubMed1976

Organisms associated with abortion and reproductive problems in cattle.

In 14 herds totaling over 2000 cattle the bacterial species most frequently isolated from the vagina, fetus, and fetal membranes following abortion or reproductive failure were Streptococcus, Corynebacterium, Bacillus, and Staphylococcus, less often E coli. About 5% of the total 1810 isolations included various other agents. Although most of the aborted fetuses had undergone autolysis, pulmonary, hepatic, renal, and placental lesions were observed in a few cases.

Abortion, Veterinary↗
PubMed1988

Psychobiology of sexual behavior in a whiptail lizard, Cnemidophorus inornatus.

This study investigated the effects of social environment on gonadal recrudescence and sexual behavior in male and female Little Striped Whiptail lizards (Cnemidophorus inornatus). The presence of sexually active males facilitates ovarian recrudescence in conspecific females. Similarly, the presence of reproductively active females facilitates testicular recrudescence in conspecific males. Males housed with females, however, had lower average circulating concentrations of testosterone and dihydrotestosterone, and higher average concentrations of corticosterone compared to intact males housed in isolation. In other studies, the presence of reproductively active females partially restored courtship behavior in castrated males compared to castrated males housed in isolation. Despite the stimulatory effects of females on castrates, exogenous androgens are required for complete restoration of all components of sexual behavior in male C. inornatus. Females are receptive to male courtship and copulatory behavior only during the vitellogenic stages; females in previtellogenic or postovulatory ovarian stages aggressively reject male courtship advances. These findings demonstrate reciprocal effects of sexual behaviors of males and females upon each other's reproductive behavior and physiology.

Animals↗
PubMed2003

Isolation and characterization of porcine circovirus type-2 from sera of stillborn fetuses.

In order to examine an association between porcine circovirus type-2 (PCV2) infection and reproductive failure in pigs, sera (n = 171) from stillborn fetuses were collected from 3 different farms with prolonged histories of reproductive problems. These sera were tested for the presence of antibodies to PCV2 using an immunoperoxidase monolayer assay. Of the 171 sera tested, 28 had PCV2 antibody titers of > or = 1:16. When these 28 samples were tested by a polymerase chain reaction assay,13 were found to contain PCV2 viral DNA. Of these 13 samples containing both PCV2 antibodies and viral DNA, 9 yielded PCV2 on virus isolation. Amino acid sequences comprising open reading frame 2 of PCV2 from 2 of these isolates were compared to PCV2 isolates from cases of post-weaning multi-systemic wasting syndrome (PMWS). The amino acid sequences of the 2 isolates from stillborn pigs were shown to be nearly identical to each other, as well as to other PCV2 isolates associated with reproductive failure. When compared with PMWS isolates, the isolates from the stillborn fetuses showed differences of at least 2 amino acids. These results confirm previous findings that transplacental infection of PCV2 occurs in the field and that stillbirths in pigs may be associated with PCV2 infections. At present, the significance of minor differences in amino acid sequences is not known.

Amino Acid Sequence↗
PubMed2003

Clonal reproduction and limited dispersal in an environmental population of Cryptococcus neoformans var gattii isolates from Australia.

Cryptococcus neoformans var. gattii is a causative agent of cryptococcosis and is thought to have a specific ecological association with a number of Eucalyptus species in Australia. However, the role that the tree plays in the life cycle of the fungus and the nature of the infectious propagule are not well understood. This study set out to examine whether sexual recombination is occurring in a natural population of C. neoformans var. gattii and whether the fungus disseminates between colonized trees. Thirty C. neoformans var. gattii isolates, consisting of both the alpha and a mating types, were collected from 13 Eucalyptus camaldulensis trees growing along a riverbank in Renmark, South Australia. The genetic diversity within the population was studied by using amplified fragment length polymorphism fingerprinting, and each isolate was assigned a unique multilocus genotype. Population genetic analyses of the multilocus data found no evidence of genetic exchange between members of the population, indicating a clonal population structure. Canonical variate analysis was then used to study the relationship between isolates from different colonized trees. Isolates from individual trees were strongly correlated, and it appeared that dispersal between trees was not occurring to any appreciable extent. These results suggest that the eucalypt may not be the primary niche for C. neoformans var. gattii but that the decaying wood present in hollows on these trees may provide a favorable substrate for extensive clonal propagation of the yeast cells.

Australia↗
PubMed2000

ESOP-1, a secreted protein expressed in the hematopoietic, nervous, and reproductive systems of embryonic and adult mice.

To isolate soluble factors expressed in early phases of hematopoietic differentiation, we applied the signal sequence trap method to the in vitro murine hematopoietic differentiation system, in which ES cells are cocultured with OP-9 stroma cells. This strategy allowed us to isolate cDNA for a secreted protein, ESOP-1, of 160 amino acids, the sequence of which shows 64% identity with human ESOP-1/MD-2. ESOP-1 mRNA was highly expressed in the mouse embryos at 7.5 days after coitus. Expression of the ESOP-1 mRNA and protein was shown in the embryonic and adult hematopoietic system. In addition, the ESOP-1 protein was found in the yolk sac-blood islands, the developing nervous system, and the adult reproductive system. These results suggest that ESOP-1 may play some roles in the development or maintenance of hematopoietic, nervous, and reproductive systems.

Amino Acid Sequence↗
PubMed1991

Outbreaks in Quebec pig farms of respiratory and reproductive problems associated with encephalomyocarditis virus.

Encephalomyocarditis virus (EMCV) was isolated from tissues of aborted fetuses and weaned and suckling piglets from 4 different pig farms in Quebec. The farms were experiencing reproductive failure in sows of different parities concomitant to respiratory problems in suckling and postweaning piglets. At necropsy, gross lesions were confined to the lung and consisted of pulmonary congestion and edema of various degrees. Lesions of multifocal interstitial to proliferative pneumonia were found in the lungs of these piglets. Bacteriologic examination of various tissues from necropsied pigs yielded no pathogens in most cases. No significant antibody titers against 3 swine viruses (transmissible gastroenteritis virus, porcine parvovirus, and swine influenza virus) and two bovine viruses (bovine viral diarrhea and infectious bovine rhinotracheitis viruses) were detected in the sera of convalescent pigs. The Quebec EMCV isolates were antigenically related to the reference ATCC-VR129 strain of EMCV, as demonstrated by indirect immunofluorescence, serum neutralization (SN), and Western immunoblotting. However, one of the Quebec isolates could be distinguish by SN. EMCV-specific SN antibody titers up to 1:12,800 were detected in thoracic and ascitis fluids of aborted fetuses and in sera of convalescent pigs. A possible pneumotropic EMCV variant in swine may exist.

Abortion, Veterinary↗
PubMed2005

The tropical cedar tree (Cedrela fissilis Vell., Meliaceae) homolog of the Arabidopsis LEAFY gene is expressed in reproductive tissues and can complement Arabidopsis leafy mutants.

A homolog of FLORICAULA/LEAFY, CfLFY (for Cedrela fissilis LFY), was isolated from tropical cedar. The main stages of the reproductive development in C. fissilis were documented by scanning electron microscopy and the expression patterns of CfLFY were studied during the differentiation of the floral meristems. Furthermore, the biological role of the CfLFY gene was assessed using transgenic Arabidopsis plants. CfLFY showed a high degree of similarity to other plant homologs of FLO/LFY. Southern analysis showed that CfLFY is a single-copy gene in the tropical cedar genome. Northern blot analysis and in situ hybridization results showed that CfLFY was expressed in the reproductive buds during the transition from vegetative to reproductive growth, as well as in floral meristems and floral organs but was excluded from the vegetative apex and leaves. Transgenic Arabidopsis lfy26 mutant lines expressing the CfLFY coding region, under the control of the LFY promoter, showed restored wild-type phenotype. Taken together, our results suggest that CfLFY is a FLO/LFY homolog probably involved in the control of tropical cedar reproductive development.

Arabidopsis↗
PubMed2006

Genotyping of Ureaplasma diversum isolates using pulsed-field electrophoresis.

Ureaplasma diversum has been associated with reproductive disorders in cattle and in the present study genotypic variations among U. diversum isolates obtained from the vaginal mucus of healthy cattle and sick animals were analyzed by enzymatic digestion and pulsed-field gel electrophoresis (PFGE). The influence of time and broth volume was important in obtaining sufficient cell sediment and DNA for PFGE. The method presented a high discriminatory power and satisfactory reproducibility for the analysis of detected variations among U. diversum isolates and strains. Different band profiles and wide genotypic heterogeneity were detected but no association between DNA polymorphism and sick or healthy animals could be established.

Animals↗
PubMed2006

The nature of plant species.

Many botanists doubt the existence of plant species, viewing them as arbitrary constructs of the human mind, as opposed to discrete, objective entities that represent reproductively independent lineages or 'units of evolution'. However, the discreteness of plant species and their correspondence with reproductive communities have not been tested quantitatively, allowing zoologists to argue that botanists have been overly influenced by a few 'botanical horror stories', such as dandelions, blackberries and oaks. Here we analyse phenetic and/or crossing relationships in over 400 genera of plants and animals. We show that although discrete phenotypic clusters exist in most genera (> 80%), the correspondence of taxonomic species to these clusters is poor (< 60%) and no different between plants and animals. Lack of congruence is caused by polyploidy, asexual reproduction and over-differentiation by taxonomists, but not by contemporary hybridization. Nonetheless, crossability data indicate that 70% of taxonomic species and 75% of phenotypic clusters in plants correspond to reproductively independent lineages (as measured by postmating isolation), and thus represent biologically real entities. Contrary to conventional wisdom, plant species are more likely than animal species to represent reproductively independent lineages.

Analysis of Variance↗
PubMed1975

Isolation and properties of Escherichia coli mutants which are nonpermissive for the growth of phage lambda.

By selecting survivors of lambda phage infection, mutants of Escherichia coli K12 that block reproduction cycle of the phage have been isolated. Fourteen of these phage-tolerant mutants (lam mutants) were chosen and characterized biochemically and genetically. It was shown that these mutants were tolerant to infection by all the lambdoid phages, except for few cases, but they were susceptible to infection by a non-lambdoid temperate phage (phi299), P1 or T phages. The mutants can be divided into at least three groups: (1) A mutant (lam 16) strain that seems to block normal penetration of phage DNA: (2) Three mutant (lam 64, lam 67 and lam 71) strains that block an "early" step(s) of phage growth, including phage DNA synthesis: (3) Six mutant (lam 24, lam 25, lam 26, lam 27, lam 646 and lam 6) strains that block normal functioning of the gene E products and produce unusual head structures. Some lambdoid phages and lambda mutants that overcome the interference by the lam mutations have been obtained, and were used as tools for characterizing the host mutations. Two (lam 12 and lam 13) mutant strains and one (lam 1) mutant were inferred as affecting the expression of "late" genes, and early gene, respectively, by this test.

Coliphages↗
PubMedDate not supplied

Expression of interleukin-10 and interleukin-12 in piglets experimentally infected with porcine reproductive and respiratory syndrome virus (PRRSV).

The expression of mRNA encoding interleukin-10 (IL-10) and IL-12 was studied, by the reverse transcription-polymerase chain reaction and by in-situ hybridization with a non-radioactive digoxigenin-labelled cDNA probe, in formalin-fixed, paraffin wax-embedded lung tissue from piglets inoculated intranasally with a Korean isolate (North American genotype) of porcine reproductive and respiratory syndrome virus (PRRSV). IL-12p35-positive cells were detected in the lung at 1 day post-inoculation (dpi), their number increasing at 5 dpi, and rapidly decreasing thereafter. In contrast, IL-10- and IL-12p40-positive cells were detected in the lung at 1 dpi, their number increasing at 3 dpi, and rapidly decreasing thereafter. Hybridization signals for IL-10, IL-12p35 and IL-12p40 were always associated with inflammation. Expression of these cytokines was minimal in non-lesional lung of PRRSV-infected piglets and in normal lung from control piglets. In-situ hybridization in serial sections of lung tissues indicated close co-localization of PRRSV and these cytokines in interstitial pneumonia. The results suggest that the expression of IL-10 and IL-12 plays a role in pulmonary defence mechanisms against PRRSV infection.

Animals↗
PubMed2004

Expression of interferon-alpha and Mx1 protein in pigs acutely infected with porcine reproductive and respiratory syndrome virus (PRRSV).

The expression of mRNA encoding interferon-alpha (IFN-alpha) and Mx1 protein was studied, by reverse transcription-polymerase chain reaction and by in-situ hybridization with a non-radioactive digoxigenin-labelled cDNA probe, in formalin-fixed, paraffin wax-embedded lung tissue from pigs experimentally infected with a Korean isolate (North American genotype) of porcine reproductive and respiratory syndrome virus (PRRSV). The animals were examined over a period of 10 days after intranasal inoculation. IFN-alpha and Mx1 protein was detected in the lung at 1 day post inoculation (dpi), the number of positive cells increasing at 7dpi, and rapidly decreasing thereafter. Hybridization signals for IFN-alpha and Mx1 protein were usually associated with inflammation, and in particular with macrophages. Expression of IFN-alpha and Mx1 protein was negative in non-lesional lung of PRRSV-infected pigs and in normal lung from control pigs. There was a good statistical correlation between the number of cells positive for mRNA encoding IFN-alpha and Mx1 protein in the infected lungs (r = 0.95, P< 0.05). The results suggest that the expression of IFN-alpha and Mx1 protein plays a role in the early host defence against PRRSV infection.

Animals↗
PubMed1977

[Effect of Actinomyces rimosus ribonuclease on the reproduction of viruses].

Antiviral activity of RNA-ase isolated from the fermentation broth of Actinomyces rimosus was studied. The effect of the enzyme on multiplication of the viruses of vesicular stomatitis, Newcastle and cariolovaccine diseases was investigated. It was found that the enzyme was capable of suppressing reproduction of the vesicular stomatitis virus (VSV) in the culture of chick fibroblast cells. The suppression level directly depended on the enzyme concentration and decreased with an increase in the infection multiplicity. The enzyme had no effect on multiplication of other viruses tested. RNA-ase decreased the infectious properties of the freshly isolated virus-containing material in concentrations showing the antiviral effect. Preliminary incubation of the cells with the enzyme resulted in suppression of the plaque formation by VSV. The RNA synthesis in such cultures treated with RNA-ase was somewhat lower. It was shown that the antiviral effect of RNA=ase was connected with its enzymic activity. RNA-ase has no antiviral effect in the experiments with mice infected with VSV.

Animals↗
PubMed1999

A strategy for assessing the effects of xenobiotics on fish reproduction.

Environmental pollutants, such as industrial and agricultural chemicals, heavy metals, drugs and products with hormonal activity may disrupt reproduction of aquatic wildlife such as fish. Such xenobiotics may cause disruption of the reproductive endocrine system, or they may directly affect gamete development and viability as a result either of their cytotoxicity or by altering the hormonal environment during gamete development. The various possible sites of action are reviewed, and it is suggested that tests for toxicity should isolate the specific component of the reproductive system that is most sensitive to such disruption and that this may be at levels well below that which causes mortality or visible signs of stress. Fish are proposed as the most suitable aquatic organism for such tests.

Animals↗
PubMed2006

Sex, bugs and Haldane's rule: the nematode genus Pristionchus in the United States.

BACKGROUND: The nematode Pristionchus pacificus has been developed as a satellite organism in evolutionary developmental biology for comparison to Caenorhabditis elegans. Comparative studies have revealed major differences in the regulation of developmental processes between P. pacificus and C. elegans. To place evolutionary developmental biology and the observed developmental differences between species in a comprehensive evolutionary context, such studies have to be complemented with ecological aspects. Knowledge about the ecology of the organism in question might indicate specific environmental conditions that can result in developmental adaptations and could account for species differences in development. To this end, we have started to investigate the ecology of Pristionchus nematodes. In recent field studies in Western Europe we found six Pristionchus species that are closely associated with scarab beetles and the Colorado potato beetle. This Pristionchus-beetle association provides the unique opportunity to combine research in evolutionary developmental biology with ecology. However, it remains unknown how general these findings from Europe are on a global scale. RESULTS: Here, we describe the Pristionchus species associated with scarab and Colorado potato beetles in the Eastern United States and show striking transatlantic differences and unexpected evolutionary and ecological patterns. Two hundred eighty of 285 (98%) isolates from American scarab beetles belong to five Pristionchus species, all of which are different from the European species. We describe four of them as novel Pristionchus species. The five American Pristionchus species fall into a single phylogenetic clade and have a male-female (gonochoristic) mode of reproduction, whereas the majority of European isolates are hermaphroditic. Crosses between the two most closely related species, P. aerivorus and P. pseudaerivorus n. sp., follow Haldane's rule in that heterogametic F1 males are inviable. We observed P. aerivorus and P. pseudaerivorus n. sp. coexisting on the same scarab beetle and obtained two cases of F1 hybrids from wild beetles. Finally, the Colorado potato beetle is associated with the same nematode, P. uniformis in the United States and Europe. Given the introduction of the Colorado potato beetle to Europe in 1877, our results suggest that P. uniformis was introduced together with its beetle vector. CONCLUSION: Taken together, the Pristionchus-beetle association provides a powerful tool for studying biodiversity, biogeography, speciation and species invasion on a global scale.

Journal Article↗
PubMedDate not supplied

Invasion of chicken reproductive tissues and forming eggs is not unique to Salmonella enteritidis.

Experiments were conducted in which Salmonella enteritidis Phage Type 8, Phage Type 2, and RDNC (reaction does not conform) or three isolates of Salmonella typhimurium of diverse origin were fed to adult laying hens to determine if S. enteritidis has a selective advantage over S. typhimurium, which is now rarely isolated from chicken eggs, in its capacity to invade reproductive tissues. The results revealed that S. enteritidis and S. typhimurium may be equal in their potential to colonize the tissues of the reproductive tract and eggs that are forming in the oviduct prior to oviposition. S. enteritidis, but not S. typhimurium, was isolated from egg contents after oviposition. The degree to which intestinal, hepatic, splenic, or reproductive tissues were colonized by either serotype was not seen to affect the rate of colonization of eggs forming in the oviduct or the contamination of eggs after oviposition. Virulence factors related to the difference in the association of S. enteritidis and S. typhimurium with egg-borne salmonellosis remain to be defined.

Animals↗
PubMed1999

Effects of isolation on sibling recognition in prairie voles, Microtus ochrogaster.

Traditionally, sibling recognition in prairie voles has been inferred by incest avoidance or lack of reproduction among littermates. Previous studies have shown that isolation of sibling prairie voles for 8-15 days causes the breakdown of incest avoidance. However, in a re-evaluation of these studies, using social interactions within sexes (amicable versus agonistic behaviours), rather than incest avoidance, we found that incest avoidance might not be the best criterion for inferring sibling recognition in this species. When sibling prairie voles were isolated for less than 20 days, same-sex siblings still showed evidence of recognition in social encounter tests. Only after 20 days of isolation did sibling prairie voles show low levels of amicable behaviours and very high levels of agonistic behaviours; therefore, treating their siblings in the same way that they treated nonsiblings. Sibling recognition should be seen as a continuum, which can be inferred and detected experimentally at different time intervals by different approaches (incest avoidance or social interactions). Our results help to elucidate the effects of isolation on sibling recognition and help to determine the possible mechanisms responsible for the maintenance of social memory for recognition cues after periods of isolation. Copyright 1999 The Association for the Study of Animal Behaviour.

Journal Article↗