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Strains of Alternaria (Dematiaceous Hyphomycetes) isolated from lesions in men or animals generally lose quickly their ability to fructify (porospores forming) after their isolation and keeping up on artificial culture mediums classicaly used in medical diagnostic laboratories. The authors, from the fact that Alternaria are fungi which are normally parasites of living plants, put, on plantlets from germinating corn seeds (graminaceous plant) and lentil seeds (papilionaceous plant), two strains of Alternaria isolated from human cases of alternariosis which were diagnosed in their laboratory and which did not give porospores since delays reaching 14 months. They obtained, on corn plantlets, very numerous, normal and mature porospores, and on lentil plantlets, or nothing with the first strain, or very rare porospores with the second. This method, if results are confirmed by further experimentations, will be usefull for the specific determination for strains isolated from lesions and become infertile. The differences of behaviour of two strains, according the botanical family of plantlets used, come perhaps from the relative host specificity of the most numerous species of Alternaria.
This analytical overview attempts to cover the main achievements and trends in research and clinical investigation in animal and human reproductive immunology published in the 3-year period (1982-1985) between Fifth and Sixth Varna Symposia. New and successful steps have been made in immunodiagnostics, immunotherapy, and immunoprophylaxis of immunologically conditioned infertility. Considerable progress has been made in isolating and purifying immunogenic reproductive tract components that might be candidates in the preparation of contraceptive vaccines. With the modern developments in immunochemistry and cytoimmunology, including monoclonal biotechnology, new biological factors have been identified that play a role in integral regulation of the immune reactions to reproductive antigens, both locally and systemically. The practical significance of reproductive immunology is emphasized.
The presence of mycoplasma was investigated in 77 women with infertility, 34 women complaining of sterility, 92 women with vaginitis and 66 healthy control subjects. The group of infertile women was subdivided into those with one or two spontaneous abortions, those with three or more abortions and those with missed abortions. The isolation rate of mycoplasma from the vagina and cervix of the infertile women ranged from 18 to 36%. The endometrial isolation rate was 21% in women with missed abortions but lower in women of the other two subdivisions. Mycoplasmas were infrequently found in patients investigated for sterility. They were isolated at a higher rate in patients with vaginitis, especially in those with trichomonas-associated vaginitis. They were not found in healthy control subjects. In the endometria positive for mycoplasma no specific histological features for this infection were found.
The reproductive form of a macronucleus-specific symbiont Holospora obtusa, when harbored by the macronucleus of the ciliate Paramecium caudatum, selectively synthesized a 63-kDa protein which is immunologically related to GroEL, or HSP60, of Escherichia coli. Heat shock treatment of isolated cells of the reproductive and infectious form of the bacterium also induced the synthesis of the GroEL homolog. Immunoblotting showed that the amount of this protein per cell, whether the reproductive or infectious form, is roughly constant. Cloning and sequencing of a gene coding for the GroEL homolog suggested that the protein is 55.2% identical to GroEL of E. coli at the amino acid sequence level, and that the gene is preceded by an open reading frame which encodes a protein 39.6% identical to GroES of E. coli. Northern blot hybridization showed that the groEL homologous gene is highly expressed in the reproductive form, but only in a trace amount in the intermediate and infectious form. Immunoelectron microscopy revealed that the GroEL homolog is localized in the cytoplasm of the reproductive and infectious form.
Sexual reproduction in plants, unlike that of animals, requires the action of multicellular haploid gametophytes. The male gametophyte (pollen tube) is guided to a female gametophyte through diploid sporophytic cells in the pistil. While interactions between the pollen tube and diploid cells have been described, little is known about the intercellular recognition systems between the pollen tube and the female gametophyte. In particular, the mechanisms that enable only one pollen tube to interact with each female gametophyte, thereby preventing polysperm, are not understood. We isolated female gametophyte mutants named magatama (maa) from Arabidopsis thaliana by screening for siliques containing half the normal number of mature seeds. In maa1 and maa3 mutants, in which the development of the female gametophyte was delayed, pollen tube guidance was affected. Pollen tubes were directed to mutant female gametophytes, but they lost their way just before entering the micropyle and elongated in random directions. Moreover, the mutant female gametophytes attracted two pollen tubes at a high frequency. To explain the interaction between gametophytes, we propose a monogamy model in which a female gametophyte emits two attractants and prevents polyspermy. This prevention process by the female gametophyte could increase a plant's inclusive fitness by facilitating the fertilization of sibling female gametophytes. In addition, repulsion between pollen tubes might help prevent polyspermy. The reproductive isolations observed in interspecific crosses in Brassicaceae are also consistent with the monogamy model.
Strain typing of medically important fungi and fungal population genetics have been stimulated by new methods of tapping DNA variation. The aim of this contribution is to show how awareness of fungal population genetics can increase the utility of strain typing to better serve the interests of medical mycology. Knowing two basic features of fungal population biology, the mode of reproduction and genetic differentiation or isolation, can give medical mycologists information about the intraspecific groups that are worth identifying and the number and type of markers that would be needed to do so. The same evolutionary information can be just as valuable for the selection of fungi for development and testing of pharmaceuticals or vaccines. The many methods of analyzing DNA variation are evaluated in light of the need for polymorphic loci that are well characterized, simple, independent, and stable. Traditional population genetic and new phylogenetic methods for analyzing mode of reproduction, genetic differentiation, and isolation are reviewed. Strain typing and population genetic reports are examined for six medically important species: Coccidioides immitis, Histoplasma capsulatum, Candida albicans, Cryptococcus neoformans, Aspergillus fumigatus, and A. flavus. Research opportunities in the areas of genomics, correlation of clinical variation with genetic variation, amount of recombination, and standardization of approach are suggested.
Haemophilus somnus isolates from cases of thrombotic meningoencephalitis, pneumonia, and other disease sites are capable of undergoing a high rate of phase variation in the oligosaccharide component of their lipooligosaccharides (LOS). In contrast, the LOS of commensal strains isolated from the normal reproductive tract phase vary little or not at all. In addition, the LOS of H. somnus shares conserved epitopes with LOS from Neisseria gonorrhoeae, Haemophilus influenzae, and other species that can incorporate sialic acid into their LOS. We now report that growth of disease isolates of H. somnus with CMP-N-acetylneuraminic acid (CMP-NeuAc) or NeuAc added to the medium resulted in incorporation of NeuAc into the LOS. However, NeuAc was not incorporated into the LOS of commensal isolates and one disease isolate following growth in medium containing CMP-NeuAc or NeuAc. Sialylated LOS was detected by an increase in the molecular size or an increase in the amount of the largest-molecular-size LOS electrophoretic bands, which disappeared following treatment with neuraminidase. Sialylated LOS could also be detected by reactivity with Limax flavus agglutinin lectin, which is specific for sialylated species, by dot blot assay; this reactivity was also reversed by neuraminidase treatment. H. somnus strain 2336 LOS was found to contain some sialic acid when grown in medium lacking CMP-NeuAc or NeuAc, although supplementation enhanced NeuAc incorporation. In contrast strain 738, an LOS phase variant of strain 2336, was less extensively sialylated when the growth medium was supplemented with CMP-NeuAc or NeuAc, as determined by electrophoretic profiles and electrospray mass spectrometry. The sialyltransferase of H. somnus strain 738 was confirmed to preferentially sialylate the Gal(beta)-(1-3)-GlcNAc component of the lacto-N-tetraose structure by capillary electrophoresis assay. Enhanced sialylation of the strain 2336 LOS inhibited the binding of monoclonal antibodies to LOS by enzyme immunoassay and Western blotting. Furthermore, sialylation of the LOS enhanced the resistance of H. somnus to the bactericidal action of antiserum to LOS. Sialylation and increased resistance to killing by normal serum also occurred in a deletion mutant that was deficient in the terminal Gal-GlcNAc disaccharide. LOS sialylation may therefore be an important virulence mechanism to protect H. somnus against the host immune system.
Most studies of reinforcement have focused on the evolution of either female choice or male mating cues, following the long-held view in sexual selection theory that mating mistakes are typically more costly for females than for males. However, factors such as conspecific sperm precedence can buffer females against the cost of mating mistakes, suggesting that in some hybrid zones mating mistakes may be more costly for males than for females. Thus, the historical bias in reinforcement research may underestimate its frequency. In this study, we present evidence that reinforcement has driven the evolution of male choice in a hybrid zone between the highly promiscuous leaf beetles Chrysochus cobaltinus and C. auratus, the hybrids of which have extremely low fitness. In addition, there is evidence for male choice in these beetles and that male mating mistakes may be costly, due to reduced opportunities to mate with conspecific females. The present study combines laboratory and field methods to quantify the strength of sexual isolation, test the hypothesis of reproductive character displacement, and assess the link between relative abundance and the strength of selection against hybridization. We document that, while sexual isolation is weak, it is sufficient to produce positive assortative mating. In addition, reproductive character displacement was only detected in the relatively rare species. The strong postzygotic barriers in this system are sufficient to generate the bimodality that characterizes this hybrid zone, but the weak sexual isolation is not, calling into question whether strong prezygotic isolation is necessary for the maintenance of bimodality. Growing evidence that the cost of mating mistakes is sufficient to shape the evolution of male mate choice suggests that the reinforcement of male mate choice may prove to be a widespread occurrence.
Virus isolation, reverse transcription-polymerase chain reaction (RT-PCR), immunohistochemistry, and in situ hybridization methods were compared for the detection of porcine reproductive and respiratory syndrome virus (PRRSV). Seven aborted fetuses and 6 stillborn piglets naturally infected with PRRSV were used in the study. Viral antigen and viral nucleic acid were detected in macrophages and dendritic cells in the spleen, tonsil, lymph nodes, and thymus; in macrophages of liver, heart, and lung; and in endothelial cells and myocytes of the heart. Viral antigen and viral nucleic acid were most consistently detected in the spleen. Of the 13 samples, 6 were positive for PRRSV by all 4 techniques. Four (31%) samples were positive for PRRSV by RT-PCR, in situ hybridization, and virus isolation. Two (15%) samples were positive for PRRSV by virus isolation, RT-PCR, and in situ hybridization. One (8%) was positive for PRRSV by virus isolation and RT-PCR. The RT-PCR identified the presence of PRRSV more frequently than the other methods. However, when only formalin-fixed tissues are submitted, immunohistochemistry and in situ hybridization would be useful methods for the detection of PRRSV antigen and nucleic acid.
The 3'-portion of the genome of a U.S. isolate of the porcine reproductive and respiratory syndrome (PRRS) virus, ATCCVR-2332, was cloned and sequenced. The resultant 3358 nucleotides contain 6 open reading frames (ORFs) with homologies to ORFs 2 through 7 of the European strain of the PRRS virus and other members of the free-standing genus of arteriviruses. Both VR-2332 and the European isolate (called the Lelystad virus) have been identified as infectious agents responsible for the swine disease called PRRS. Comparative sequence analysis indicates that there are degrees of amino acid identity to the Lelystad virus open reading frames ranging from 55% in ORF 5 to 79% in ORF 6. Hydropathy profiles indicate that the ORFs of VR-2332 and Lelystad virus correspond structurally despite significant sequence differences. These results are consistent with the biological similarities but distinct serological properties of North American and European isolates of the virus.
Distinct differences in tha ability of isolated seminiferous tubules and interstitium to utilize steroid precursors for androgen production in vitro were observed during the reproductive cycle of the American grey squirrel, Sciurus carolinensis. In spermatogenically active testes, the seminiferous tubules and the interstitium readily synthesized androgens from labelled C21 steroid precursor; seminiferous tubules also produced significant amounts of 17alpha,20alpha-dihydroxyprogesterone. However, during sexual regression androgen synthesis was drastically reduced in both testicular components, while the production of 20alpha-reduced metabolites of progesterone and 17alpha-hydroxyprogesterone was increased. Many of the fine-structural changes occurring in Leydig and Sertoli cells during the reproductive cycle could be correlated with the capacity of isolated seminiferous tubules and interstitium to formulate androgens from labelled precursors.
We have investigated the presence of endophytic fungi associated with rose plants (Rosa hybrida) in Colombia. Endophytic fungi were isolated from healthy leaves of ten ornamental roses plants from gardens cultured in malt extract, peptone, yeast extract agar plates (MPY). We sampled 560 leaves fragments, 56 per sample. Endophytic fungi comprised 92 isolates (16.4%); of these isolates, 41 were classified as sterile mycelium (without reproductive structures that allowed their identification), 31 isolates were identified to genus or to species, and 20 isolates could not be identified at all. The identified endophytic fungi were as follow: Nigrospora oryzae, Aureobasidium spp, Acremonium spp. The fungi Nodulisporium sp, Gliocladium virens, Cladosporium sp, Alternaria sp, Phoma sp and Chaetomium globosum were represented by one isolate each. Since the endophytic fungi are known for their capacity to produce metabolites with biological activity, it is possible that the microorganisms found in this study have potential as antagonist of rose pathogens.
Salmonella and Arizona spp. were isolated from various sites of the digestive and reproductive tracts of lizards. The finding that bacteria in the oviducts and in the internal contents of oviductal eggs were of the same serotype raises the possibility that transovarian bacterial transmission in lizards occurs in nature.
Population genetic theory predicts that in small populations, random genetic drift will fix and accumulate slightly deleterious mutations, resulting in reduced reproductive output. This genetic load due to random drift (i.e., drift load) can increase the extinction risk of small populations. We studied the relationship between genetic variability (indicator of past population size) and reproductive output in eight isolated, natural populations of the hermaphroditic snail Lymnaea stagnalis. In a common laboratory environment, snails from populations with the lowest genetic variability mature slower and have lower fecundity than snails from genetically more variable populations. This result suggests that past small population size has resulted in increased drift load, as predicted. The relationship between genetic variability and reproductive output is independent of the amount of nonrandom mating within populations. However, reproductive output and the current density of snails in the populations were not correlated. Instead, data from the natural populations suggest that trematode parasites may determine, at least in part, population densities of the snails.
Since it was first described in Australia in 1994, Hendra virus (HeV) has caused two outbreaks of fatal disease in horses and humans, and an isolated fatal horse case. Our preliminary studies revealed a high prevalence of neutralizing antibodies to HeV in bats of the genus PTEROPUS:, but it was unclear whether this was due to infection with HeV or a related virus. We developed the hypothesis that HeV excretion from bats might be related to the birthing process and we targeted the reproductive tract for virus isolation. Three virus isolates were obtained from the uterine fluid and a pool of foetal lung and liver from one grey-headed flying-fox (Pteropus poliocephalus), and from the foetal lung of one black flying-fox (P. alecto). Antigenically, these isolates appeared to be closely related to HeV, returning positive results on immunofluorescent antibody staining and constant-serum varying-virus neutralization tests. Using an HeV-specific oligonucleotide primer pair, genomic sequences of the isolates were amplified. Sequencing of 200 nucleotides in the matrix gene identified that these three isolates were identical to HeV. Isolations were confirmed after RNA extracted from original material was positive for HeV RNA when screened on an HeV Taqman assay. The isolation of HeV from pteropid bats corroborates our earlier serological and epidemiological evidence that they are a natural reservoir host of the virus.
Renal agenesis (RA) appears to be a multifactorial condition with combined genetic and environmental influences. We performed a retrospective case-control study of reproductive history of 26 isolated RA live births cases referred to Sicilian Registry of Congenital Malformations. A statistical significant association for birth weight if we considered all RA together and for bilateral RA alone, an increasing risk for maternal age only in the bilateral RA subgroup and a male predominance both for unilateral and bilateral RA was found. Our results show that some reproductive risk factors may be associated with RA, moreover differences found between subgroups indicate that some risk factors may be different in unilateral and bilateral RA. The association between reproductive risk factors and RA may reflect pathogenetic interaction between genetic and environmental factors. Nevertheless further studies are needed to clarify these associations and to explore the role of perinatal factors in the etiology of renal agenesis. In fact if prenatal or perinatal risk factors are in a causal chain influencing the risk for developing RA, then these data could have important implications in the prevention or treatment of this condition.