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PubMed2004

Mixed inoculations of a microsporidian parasite with horizontal and vertical infections.

Mixed infections, where more than one parasite genotype is present in a single host, have been suggested to be an important factor in host-parasite interactions. As the host represents a limited resource, co-infecting parasite genotypes are expected to be under resource competition. Competition will not only modify the survival of the co-infecting genotypes, but is also likely to affect total within-host parasite growth as well as host survival and reproduction. We measured parasite infectivity and spore production of seven isolates of Octosporea bayeri (Microsporidia) and their effect on the reproduction and longevity of its host Daphnia magna (Cladocera), after single- or double-isolate inoculations through vertical and horizontal transmission. Double-isolate inoculations increased parasite infectivity and total spore production in horizontal infections, but had no significant effect on host reproduction or longevity. The increase in spore production in double-isolate inoculations was not found when infections occurred vertically. Our results suggest that, depending on the way the infection was acquired, within-host reproduction can increase as a result of parasite genetic diversity, without necessarily affecting the host's fitness. Whether this challenges the current views of virulence evolution depends on the definitions used.

Animals↗
PubMed1997

[Poliovirus (Sabin strain) multiplication in human intestinal tract after oral polio vaccination].

Fecal specimens from a baby vaccine were collected every day from 1 to 51 days after primary vaccination and from 0 to 15 days after secondary vaccination. Polioviruses were isolated with GMK-2 cell line from 10% emulsion of the feces and titrated the virus contents in the emulsion of the feces. The isolated viruses were tested the reproductive capacity at 39.0 degrees C and 39.5 degrees C by the plaque method with primary cynomologous monkey kidney cells. Viruses were isolated from the feces during 28 days for type 1, 39 days for type 2 and 36 days for type 3 after primary vaccination, however, only type 1 viruses were isolated during 7 days after secondary vaccination. The multiplication of type 3 viruses in the intestine were increased after diminished the multiplication of type 1 and type 2. In plaque formation capacity at 39.0 degrees C and 39.5 degrees C, the isolates had shown to differ clearly among the types of poliovirus. After primary vaccination, type 1 isolates were not produced the plaques at 39.0 degrees C and 39.5 degrees C. Although type 2 isolates were not formed the plaques until the 14th day at 39.5 degrees C, the plaque formation capacity of the these isolates were increased gradually i.e.; on the 20th day (10(0.88) PFU/ml), the 26th day (10(2.00) PFU/ml) and the 39th day (10(2.63) PFU/ml) at 39.5 degrees C, and all of type 2 isolates tested were showed the plaque formation capacity (10(2.88 approximately 10(3.76) PFU/ml) at 39.0 degrees C. Type 3 isolates were formed plaques at 39.0 degrees C and 39.5 degrees C from the 7th day. After the secondary vaccination, type 1 isolates (7th day) was a little changed them. Neutralizing antibody titers were shown that type 1 was 320, type 2 was 110 and type 3 was 60 after 1 year of the second administration. These titers were closely similar the geometric mean titers of 2 year old babies in Japan.

Humans↗
PubMed2005

Pelvic free fluid: clinical importance for reproductive age women with blunt abdominal trauma.

OBJECTIVE: To evaluate the importance of isolated pelvic free fluid (FF) detected by ultrasound examination in pregnant patients and in non-pregnant reproductive age women with blunt abdominal trauma (BAT). METHODS: Reproductive age women aged 10-50 years who presented with BAT and underwent focused abdominal sonography for trauma (FAST) from January 1995 to June 2002 at a Level 1 trauma center were included. Patients were assigned to four groups according to the location of FF detected by ultrasound (Group 1, no FF; Group 2, FF in pelvis; Group 3, FF in abdomen; Group 4, FF in abdomen and pelvis). Ultrasound findings were compared with intra-abdominal and pelvic injuries detected by computed tomography and/or laparotomy. Pair-wise comparison was performed using a Fisher's exact test. RESULTS: Ultrasound detection of FF in the abdomen alone or FF in the abdomen and pelvis was significantly associated with intra-abdominal injury (IAI) compared to those without FF (P < 0.001) for both pregnant and non-pregnant reproductive age women. FF isolated to the pelvis was also associated with a higher injury rate compared to no FF in pregnant women (30% vs. 3%, P = 0.005) and in non-pregnant reproductive age women (39.5% vs. 3.7%, P < 0.001). CONCLUSIONS: In reproductive age women with BAT, ultrasound detection of FF in the abdomen alone, in both the abdomen and pelvis, or isolated to the pelvis is associated with a higher IAI rate. Therefore, isolated FF in the pelvis should not necessarily be considered physiological in pregnant and non-pregnant patients with BAT.

Abdominal Injuries↗
PubMed2001

The nsdD gene encodes a putative GATA-type transcription factor necessary for sexual development of Aspergillus nidulans.

The ability to reproduce both sexually and asexually is one of the characteristics of the homothalic ascomycete Aspergillus nidulans. Unlike the other Aspergillus species, A. nidulans undergoes sexual development that seems to be regulated by internal and external stimuli. To begin to understand the sexual reproduction of A. nidulans we previously isolated and characterized several NSD (never in sexual development) mutants that failed to produce any sexual reproductive organs, and identified four complementation groups, nsdA, nsdB, nsdC, and nsdD. The nsdD gene has been isolated, and it is predicted to encode a GATA-type transcription factor with the type IVb zinc finger DNA-binding domain. The mRNA of the nsdD gene started to accumulate in the early phase of vegetative growth, and the level increased as sexual development proceeded. However, it decreased during asexual sporulation and no nsdD mRNA was detected in conidia. Deletion of nsdD resulted in no cleistothecia (fruiting bodies) formation, even under the conditions that preferentially promoted sexual development, indicating that nsdD is necessary for sexual development. In contrast, when the nsdD gene was over-expressed, sexual-specific organ (Hülle cell) was formed even in submerged culture, which normally completely blocked sexual development, and the number of cleistothecia was also dramatically increased on solid medium. These results lead us to propose that the nsdD gene functions in activating sexual development of A. nidulans. Multiple copies of the nsdD gene could suppress nsdB5 and veA1, indicating that either nsdD acts downstream of these genes or possibly functions in overlapping pathway(s).

Aspergillus nidulans↗
PubMed1979

Unusual Baculovirus of the Parasitoid Wasp Apanteles melanoscelus: Isolation and Preliminary Characterization.

A baculovirus present in the female reproductive tract of the parasitoid wasp Apanteles melanoscelus has been isolated and partially characterized. Viral DNA is double stranded, circular, and of highly variable molecular weight ranging from 2 x 10(6) to 25 x 10(6); the DNA is of homogeneous density at rho = 1.694 g/ml. Acrylamide gels resolve 18 polypeptide bands in the case of purified virions; four to five of these appear in a semipurified nucleocapsid preparation. The electrophoretic profiles obtained are compared with those of two other baculoviruses.

Journal Article↗
PubMed1997

Monoclonal antibodies to the ORF5 product of porcine reproductive and respiratory syndrome virus define linear neutralizing determinants.

Complementary DNA encoding the ORF5 gene of a Quebec reference isolate (IAF-Klop) of porcine reproductive and respiratory syndrome virus (PRRSV) was cloned into the prokaryotic expression vectors pGEX-4T and pET21a to produce ORF5-glutathione S-transferase and ORF5-polyhistidine fusion proteins. Five hybridoma cell lines producing monoclonal antibodies (MAbs) to the 25 kDa viral envelope glycoprotein (GP5) were obtained from BALB/c mice immunized with the affinity chromatography-purified GST-ORF5 fusion protein. The polypeptide specificity of these anti-PRRSV MAbs, belonging to the IgG1 isotype, was confirmed by Western immunoblotting assays with recombinant and native viral proteins, and by radioimmunoprecipitation using [35S]methionine-labelled concentrated extracellular virus. All these MAbs showed virus-neutralizing (VN) activity, with VN titres ranging from 1:32 to 1:128. Two MAbs (IAF-1B8 and IAF-8A8) reacted with similar titres with the modified live attenuated vaccine strain ATCC VR-2332, but all five failed to react to the prototype European strain, the Lelystad virus, in VN and indirect immunofluorescence tests. The results obtained suggest that these five anti-PRRSV MAbs are directed to serotype-specific linear neutralizing epitopes which are not affected by the absence of carbohydrate residues.

Animals↗
PubMed1980

A method for studying the effect of inhibitors on the development of the isolated gonidia of Volvox tertius.

During asexual reproduction in Volvox tertius, a single cell, the gonidium, contained within the parental spheroid, undergoes enlargement followed by multiple cleavages. A method has been developed for the isolation and maintenance of gonidia in vitro in paraffin chambers. In these chambers development of the gonidium to a multicellular spheroid and subsequent inversion was apparently normal. The paraffin chambers allowed the monitoring of the effects of inhibitors on development without the possible interference of the parental spheroid. Enlargement and division of isolated gonidia was prevented by actinomycin D, cycloheximide and streptomycin. Division but not enlargement was inhibited by 5-fluorouracil, mitomycin C and ethidium bromide. Colchicine at high concentrations prevented inversion, as did streptomycin, cycloheximide and actinomycin D.

Anti-Bacterial Agents↗
PubMed2006

A conserved RAS/mitogen-activated protein kinase pathway regulates DNA damage-induced cell death postirradiation in Radelegans.

Although the epidermal growth factor receptor (EGFR) signaling pathway is overactive in more than half of human cancers and mediates resistance to cytotoxic therapy, the molecular mechanisms of EGFR pathway-mediated resistance have remained elusive in cancer research. This difficulty partly stems from the lack of tissue models enabling clear separation of the many forms of cell death that the downstream signaling pathways of EGFR affect. We have created a model in Caenorhabditis elegans of radiation-induced reproductive cell death ("Radelegans") in isolation of all other forms of cell death. We have employed Radelegans to genetically define the role of the EGFR signaling pathway in protection from reproductive cell death, the primary form of tumor stem or clonogen cell death postirradiation. We have found that the RAS/mitogen-activated protein kinase (MAPK) downstream signal transduction pathway of EGFR is critical for protection from reproductive cell death in Radelegans. In addition, we have shown that RAS/MAPK pathway signaling is genetically linear with the DNA damage response pathway and acts downstream of the DNA damage checkpoint in the radioresponse, implicating this pathway in DNA repair post-cytotoxic therapy. These findings support the hypothesis that enhanced repair is a mechanism of RAS/MAPK pathway-mediated resistance to cytotoxic therapy through its interaction with the DNA damage response pathway postirradiation. We postulate that these findings also help explain why current treatment strategies, based on the presumption that tumors have ineffective repair compared with normal tissues, are ineffective in EGFR/RAS/MAPK pathway-mediated tumors. Radelegans is a platform to further define the genetic basis of the radiation response in tissues.

Animals↗
PubMed2001

Mollusk-derived growth factor: cloning and developmental expression in the central nervous system and reproductive tract of Aplysia.

We have isolated and characterized an atrial gland cDNA that corrects the previously reported sequence for Aplysia atrial gland granule-specific antigen (AGSA), a glycoprotein of unknown function. We designated the protein mollusk-derived growth factor (MDGF) to distinguish the revised sequence from AGSA and to emphasize its similarity to an insect-derived growth factor (IDGF). We describe MDGF mRNA expression that suggests a possible role during embryonic development and CNS injury repair.

Adenosine Deaminase↗
PubMed2004

Reproductive character displacement is not the only possible outcome of reinforcement.

We study the form of the clines in a female mating preference and male display trait using simulations of a hybrid zone. Allopatric populations of two species are connected by demes in a stepping stone arrangement. Results show that reproductive character displacement (a pattern of increased prezygotic isolation in sympatry compared with allopatry) may or may not result when there is reinforcement (defined here as the strengthening of prezygotic isolation as a result of selection against hybrids, relative to the amount of prezygotic isolation present when hybrids are not selected against). Further, reproductive character displacement of the preference may or may not occur when it occurs in the male display. We conclude that the absence of reproductive character displacement is not evidence against the operation of reinforcement.

Animals↗
PubMed1987

[The social parameters of family reproduction in Saguenay (1842-1911)].

"The family files in the population network files of the Saguenay [Canada] are used here to isolate the social parameters of family reproduction in the region between 1842 and 1911, which corresponds to the period of population settlement. Particular attention is paid to a) the kinship tie as a support of rural society, as studied through several forms of coresidence, b) the inequalities accompanying the transmission of land and the establishment of children, and c) literacy as an indicator of social differentiation. It was observed that, despite disparities created between elder and younger sons and between boys and girls, family reproduction pursued an egalitarian course. This orientation was to be compromised, however, by the tensions and constraints accompanying the saturation of arable lands around 1920 to 1930." (SUMMARY IN ENG AND SPA)

Agriculture↗
PubMed1991

Identification of sylvatic Trichinella (T3) in foxes from France.

Thirty-three foxes (Vulpes vulpes) from a sample of 1912 collected in France were found to be infected with Trichinella spp. Four isolates were obtained for genetic identification. Isoenzymatic and biological analysis of these isolates revealed the presence of two distinct genetic types of Trichinella, Trichinella spiralis s.str. (T1) and Trichinella sp. (T3) (Trichinella nelsoni according to Soviet authors) in the fox population. The reproductive capacity index of these isolates in Wistar rats was high for T. spiralis and low for T3. This is the first report of T3 type from wild animals in France. The epidemiological implications are discussed.

Animals↗
PubMed2006

Genetic variation for outcrossing among Caenorhabditis elegans isolates.

The evolution of breeding systems results from the existence of genetic variation and selective forces favoring different outcrossing rates. In this study we determine the extent of genetic variation for characters directly related to outcrossing, such as male frequency, male mating ability, and male reproductive success, in several wild isolates of the nematode Caenorhabditis elegans. This species is characterized by an androdioecious breeding system in which males occur with hermaphrodites that can either self-fertilize or outcross with males. We find genetic variation for all characters measured, but also find that environmental variation is a large fraction of the total phenotypic variance. We further determine the existence of substantial genetic variation for population competitive performance in several laboratory environments. However, these measures are uncorrelated with outcrossing characters. The data presented here contribute to an understanding of male maintenance in natural populations through their role in outcrossing.

Animals↗
PubMed1989

Social cues can play a role in timing onset of the breeding season of the ewe.

Female Suffolk sheep were pinealectomized around the vernal equinox to eliminate the major environmental input to the reproductive system (photoperiod) and then either isolated from, or maintained with, pineal-intact gonad-intact sheep. The ewes were ovariectomized and treated with constant-release oestradiol implants and reproductive state was monitored by measuring serum LH concentrations. Pinealectomized ewes that were isolated from the normal flock showed a 2 1/2-month delay in onset of the seasonal rise in LH values compared with that of pineal-intact controls (18 November vs 5 September). On the other hand, pinealectomized ewes that were maintained with the flock showed an onset of the seasonal rise in LH that was not delayed. These results suggest a timekeeping role for social cues for timing onset of the breeding season in an animal that normally relies on photoperiodic signals for temporal regulation of the seasonal reproductive cycle.

Animals↗
PubMed2025

Unisexual reproduction in the global human fungal pathogen Cryptococcus neoformans.

The human fungal pathogen Cryptococcus species complex (encompassing Cryptococcus neoformans, Cryptococcus deneoformans, and the Cryptococcus gattii species complexes) exhibits diversity in sexual reproduction, including &#x3b1;-a mating, pseudosexual reproduction, as well as unisexual reproduction initiated from a single isolate or between isolates of the same mating type. A central conundrum is that while most Cryptococcus natural populations exhibit significant &#x3b1; mating-type bias, genetic and genomic analyses show recombination occurs in nature. The discovery of unisexual reproduction in C. deneoformans provided insight; however, thus far, unisexual reproduction has never been directly observed in the predominant global pathogenic species C. neoformans. Here, we provide evidence that mutating the RIC8 gene, which encodes a conserved guanine nucleotide exchange factor (GEF) involved in both chaperoning and activating G&#x3b1; proteins, enables unisexual reproduction in C. neoformans. Additionally, we show that genetic variation in the natural population promotes unisexual reproduction, and unisexual reproduction in C. neoformans involves canonical meiotic recombination. Finally, we found that deletion of both GPA2 and GPA3 in the MAT&#x3b1; background leads to self-filamentation without sporulation, suggesting that differential modulation of the G&#x3b1; proteins, likely involving Ric8, could underlie the switch between different modes of sexual reproduction in Cryptococcus. Our study further highlights that the highly conserved Ric8 GEF can act as an important regulator of cellular development in response to environmental stimuli and could modulate sexual reproduction in nature. We hypothesize that unisexual reproduction occurs much more frequently in nature than currently appreciated, and possibly in other fungi and microbial eukaryotes as well.

Cryptococcus neoformans↗
PubMed2025

Unisexual reproduction in the global human fungal pathogen Cryptococcus neoformans.

The human fungal pathogen Cryptococcus species complex (encompassing C. neoformans, C. deneoformans, and the C. gattii species complexes) exhibit diversity in sexual reproduction, including &#x3b1;-a mating, pseudosexual reproduction, as well as unisexual reproduction initiated from a single isolate or between isolates of the same mating type. A central conundrum is that while most Cryptococcus natural populations exhibit significant &#x3b1; mating-type bias, genetic and genomic analyses show recombination occurs in nature. The discovery of unisexual reproduction in C. deneoformans provided insight; however, thus far unisexual reproduction has never been directly observed in the predominant global pathogenic species C. neoformans. Here, we provide evidence that mutating the RIC8 gene, which encodes a conserved guanine nucleotide exchange factor (GEF) involved in both chaperoning and activating G&#x3b1; proteins, enables unisexual reproduction in C. neoformans. Additionally, we show that genetic variation in the natural population promotes unisexual reproduction, and unisexual reproduction in C. neoformans involves canonical meiotic recombination. Finally, we found that deletion of both GPA2 and GPA3 in the MAT&#x3b1; background leads to self-filamentation without sporulation, suggesting that differential modulation of the G&#x3b1; proteins, likely involving Ric8, could underlie the switch between different modes of sexual reproduction in Cryptococcus. Our study further highlights that the highly conserved Ric8 GEF can act as an important regulator of cellular development in response to environmental stimuli and could modulate sexual reproduction in nature. We hypothesize that unisexual reproduction occurs much more frequently in nature than currently appreciated, and possibly in other fungi and microbial eukaryotes as well.

G protein↗