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Results for “mating”

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PubMed1979

Purification and partial characterization of a factor, a mating hormone produced by mating-type-a cells from Saccharomyces cerevisiae.

Cells of Saccharomyces cerevisiae exhibiting the a mating type secrete into the culture medium a mating-type-specific hormone activity (a factor), which specifically causes a transient arrest of DNA replication and cell division in cells of the opposite mating type, alpha. Three compounds exhibiting a factor activity have been found in culture filtrates from a cells. The most active compound has been purified more than 10(5)-fold and appears to be homogeneous on the basis of thin-layer chromatography and thin-layer electrophoresis in different systems. We propose that this compound, which exhibits in alpha cells the biological activities that have been attributed to a factor, represents pure a factor. a factor has been characterized as a very hydrophobic undecapeptide with the following amino acid composition: H2N-Tyr (Asx1, Gly1, Ala1, Val1, Ile2, Phe1, Lys1, Trp1, Pro1). Although in their respective target cells the biological effects of a factor and of alpha factor, the corresponding mating hormone of mating-type-alpha cells, are remarkably similar, the primary structures of both hormones appear to be quite different.

Agglutination↗

PubMed2006

Effects of estrogen in the male rat medial amygdala: infusion of an aromatase inhibitor lowers mating and bovine serum albumin-conjugated estradiol implants do not promote mating.

In male rats, copulatory behavior depends on estrogen-responsive neurons located in brain areas known to be crucial for mating. Blocking the aromatization of testosterone (T) to estradiol (E(2)) either throughout the brain or within the medial preoptic area (MPO) reduces mating, whereas E(2) treatment of either the MPO or the medial amygdala (MEA) maintains sexual behavior. The effects of T aromatization in the MEA have received less attention; therefore, 2 studies were done to further elucidate the effects of E(2) in the MEA. In experiment 1, gonadally intact male rats that showed robust mating behavior were administered chronic fadrozole, a nonsteroidal aromatase inhibitor, to the MEA to stop the conversion of T to E(2) and then paired with receptive females. Infusion of fadrozole to the MEA significantly lowered mating behavior in experimental males compared to vehicle-infused control males. To further investigate the mechanism by which E(2) acts in the MEA, in experiment 2, E(2) conjugated to bovine serum albumin (BSA-E(2): a complex of E(2 )and a large protein that does not cross the plasma membrane, thereby restricting the action of E(2) to cell-surface signaling) was chronically administered bilaterally to the MEA of castrated, dihydrotestosterone-treated males. This treatment did not maintain mating behavior. These studies show that E(2) acts in the MEA to promote male sexual behavior and suggest an intercellular mechanism of E(2) action.

Amygdala↗

PubMed1985

Mates of schizophrenic mothers. A study of assortative mating from the American-Danish high risk project.

Both mates of schizophrenic mothers and a control group consisting of mates of non-schizophrenic mothers were diagnostically examined. The former were more frequently psychiatrically deviant than their controls, both with respect to a life-time syndrome diagnosis and a personality diagnosis. Mating between a schizophrenic mother and a father who suffered from schizophrenia spectrum disorder significantly increased the offspring's risk of developing a schizophrenia spectrum disorder himself. Assortative mating was negatively correlated with age of onset of maternal schizophrenia. It is proposed that defective emotional rapport or sub-psychotic features constitute the phenotypic traits by which assortative mating operates in schizophrenia.

Adult↗

PubMed2001

Demographic analysis of delayed mating in mating disruption: a case study with Cryptophelbia illepida (Lepidoptera: Tortricidae).

Laboratory-derived life tables were used to determine the effect of delaying mating of adult female koa seedworm, Cryptophlebia illepida (Butler) (Lepidoptera: Tortricidae), 4 and 6 d on population growth rates. Leslie matrices were developed from the life tables and used to project the effects for approximately four generations. Delay of mating caused a decrease in population growth rate and also resulted in asynchronous population cycling between control (1-d delay) and the delayed treatments. By the fourth generation, the control population began to increase 10 and 14 d before the 4- and 6-d delay treatments, respectively. Increasing the mortality of females during the first 7 d of adult life resulted in a greater reduction of the populations where mating was delayed than in the control populations. This result suggests that even at relatively low levels of natural enemy mortality, there is a synergistic effect when mating is delayed. The implications of these effects on mating disruption management programs are discussed.

Animals↗

PubMed1994

Linkage of mating-type loci distinguishes bipolar from tetrapolar mating in basidiomycetous smut fungi.

Sexual compatibility requires self vs. non-self recognition. Genetically, two compatibility or mating-type systems govern recognition in heterothallic basidiomycete fungi such as the edible and woodrotting mushrooms and the economically important rust and smut phytopathogens. A bipolar system is defined by a single genetic locus (MAT) that can have two or multiple alleles. A tetrapolar system has two loci, each with two or more specificities. We have employed two species from the genus Ustilago (smut fungi) to discover a molecular explanation for the genetic difference in mating systems. Ustilago maydis, a tetrapolar species, has two genetically unlinked loci that encode the distinct mating functions of cell fusion (a locus) and subsequent sexual development and pathogenicity (b locus). We have recently described a b locus in a bipolar species, Ustilago hordei, wherein the existence of an a locus has been suspected, but not demonstrated. We report here the cloning of an allele of the a locus (a1) from U. hordei and the discovery that physical linkage of the a and b loci in this bipolar fungus accounts for the distinct mating system. Linkage establishes a large complex MAT locus in U. hordei; this locus appears to be in a region suppressed for recombination.

Alleles↗

PubMed1991

Cloning the mating types of the heterothallic fungus Podospora anserina: developmental features of haploid transformants carrying both mating types.

DNAs that encode the mating-type functions (mat+ and mat-) of the filamentous fungus Podospora anserina were cloned with the use of the mating-type A probe from Neurospora crassa. Cloning the full mat information was ascertained through gene replacement experiments. Molecular and functional analyses of haploid transformants carrying both mating types lead to several striking conclusions. Mat+ mat- strains are dual maters. However, the resident mat information is dominant to the mat information added by transformation with respect to fruiting body development and ascus production. Moreover, when dual mating mat+ mat- strains are crossed to mat+ or mat- testers, there is strong selection, after fertilization, that leads to the loss from the mat+ mat- nucleus of the mat information that matches that of the tester. Finally, the mat locus contains at least two domains, one sufficient for fertilization, the other necessary for sporulation.

Ascomycota↗

PubMed1993

Deletion of the mating-type sequences in Podospora anserina abolishes mating without affecting vegetative functions and sexual differentiation.

The mating-type locus of Podospora anserina controls fusion of sexual cells as well as subsequent stages of development of the fruiting bodies. The two alleles at the locus are defined by specific DNA regions comprising 3.8 kb for mat+ and 4.7 kb for mat-, which have identical flanking sequences. Here we present the characterization of several mutants that have lost mat(+)-specific sequences. One mutant was obtained fortuitously and the other two were constructed by gene replacement. The mutants are deficient in mating with strains of either mat genotype but are still able to differentiate sexual reproductive structures. The loss of the mating type does not lead to any discernible phenotype during vegetative growth: in particular it does not change the life span of the strain. The mutants can recover mating ability if they are transformed with DNA containing the complete mat+ or mat- information. The transformants behave in crosses as do the reference mat+ or mat- strains, thus indicating that the transgenic mat+ and mat- are fully functional even when they have integrated at ectopic sites.

Alleles↗

PubMed2006

Cloning of the mating type locus from Ascochyta lentis (teleomorph: Didymella lentis) and development of a multiplex PCR mating assay for Ascochyta species.

The mating type (MAT) locus of the lentil pathogen, Ascochyta lentis, was cloned and characterized using thermal asymmetric interlaced and inverse PCR with primers designed to the HMG-box of Ascochyta rabiei. A multiplex PCR assay for mating type was developed based on MAT idiomorph and flanking sequences. Primers were designed to specifically amplify MAT from several Ascochyta spp. including A. pisi, A. fabae and A. viciae-villosae in addition to A. lentis. Four hundred and fifty and 700 bp fragments were amplified from MAT1-1 and MAT1-2 isolates, respectively, and fragment size correlated perfectly with laboratory crosses using mating type tester strains. MAT-specific PCR allowed rapid scoring of mating type in crude DNA extracts from geographically diverse population samples of A. viciae-villosae from California and Washington State, USA. This co-dominant MAT-specific PCR assay will be a valuable tool for studying the population structure, biology and epidemiology of these fungi.

Amino Acid Sequence↗

PubMed2006

"Some guys have all the luck": mate preference influences paced-mating behavior in female rats.

In the present study, mating behavior was observed in female rats that were given the opportunity to mate with two males simultaneously. Three groups of females were tested: 1) sexually naïve, naturally cycling rats in proestrous; 2) sexually naïve, hormone-primed, ovariectomized (OVX) rats; and 3) hormone-primed, OVX rats tested 1 week after sexual receptivity testing. One male rat was determined to be the preferred male for each female, if she spent more time with him during a mating test. Independent of sexual experience, female rats were less likely to leave their preferred male than their non-preferred male following intromissions. However, when they left their preferred male, they returned to him faster than to their non-preferred male. This effect of preference was slightly more robust in the OVX rats. When female rats from Group 2 were tested with the same pair of males for 3 additional tests, each female's preference for a particular male was stable. That is, a female rat preferred the same male in approximately 3 out of the 4 tests, which is more likely than would be expected by chance. In a final experiment, pairs of male rats were tested with different females once weekly to determine if different females would prefer particular males consistently. Although no male rat was preferred by all females, females consistently preferred the same male from each pair during approximately 70% of the tests. In conclusion, female mate preference may have adaptive significance for the reproductive success of rats.

Analysis of Variance↗

PubMed1994

The fission yeast mating pheromone P-factor: its molecular structure, gene structure, and ability to induce gene expression and G1 arrest in the mating partner.

Schizosaccharomyces pombe h+ cells secrete a diffusable mating pheromone called P-factor. Here we show that the map2 gene, a defect of which confers h(+)-specific sterility, encodes the precursor of P-factor. We purified P-factor from cells overexpressing map2 and determined its amino acid sequence. P-factor is a peptide of 23 residues, with the sequence Thr-Tyr-Ala-Asp-Phe-Leu-Arg-Ala-Tyr-Gln-Ser- Trp-Asn-Thr-Phe-Val-Asn-Pro-Asp-Arg-Pro-Asn-Leu. A synthetic peptide of this sequence gave the same specific activity and chromatographic profile as the purified P-factor, suggesting that P-factor is unmodified. h- cells starved for nutrition showed a morphological response to P-factor. Transcription of the sxa2 gene, which encodes a protease thought to degrade P-factor, was activated in these cells. The cry1 null mutant, which lacks adenylyl cyclase and has little intracellular cAMP, was susceptible to P-factor even in the presence of nutrients. Combination of the cyr1 and sxa2 mutations enhanced this susceptibility. P-factor induced not only responses toward mating but also arrest of the cell cycle at the G1 phase in h- cyr1 sxa2 cells. This proves that the S. pombe mating pheromone has the ability to arrest cell cycle progression, which has previously been obscured by the usual requirement for mating of nutritional starvation and subsequent growth arrest.

Amino Acid Sequence↗

PubMed2006

Mating behavior and endocrine profiles of wild black and white Colobus monkeys (Colobus guereza): toward an understanding of their life history and mating system.

Black and white colobus monkeys (Colobus guereza, "guerezas") show no external signs of estrus, and little is known about their mating behavior or reproductive endocrinology. To learn more about the life history characteristics and mating system of guerezas, we documented the mating behavior and ovarian hormone profiles of 10 cycling, lactating, and pregnant females in a wild population. We studied six groups of guerezas in Kibale National Park, Uganda, and collected ad libitum data on their mating behavior. We collected urine samples every 1.9+/-0.2 days from potentially fertile females and quantified conjugated urinary estrogen (E1S) and progesterone (PdG) metabolites using enzyme immunoassay (EIA). Females solicited 50.5% of copulations, and most copulations occurred during the interval starting 5 days before presumptive ovulation and ending 2-3 days later, with the highest copulatory levels occurring close to ovulation. We show that the median ovarian cycle length is 24 days, the median gestation length is approximately 158 days, the length of lactational amenorrhea is at least 7-8 months, and the median interbirth interval for females with surviving infants is approximately 22 months. We also document overlap between females' receptive periods in one-male, two- to three-female groups, which may mean that male transfer into such groups is potentially profitable.

Amenorrhea↗

PubMed1975

The mating reaction in yeast. II. Spontaneous occurrence of omni-mating types.

Meiosis in diploids of Saccharomyces cerevisiae either homozygous or heterozygous for the dmt gene result, in about 5% of the meiotic products, in spores which have undergone an interconversion at the mating-type locus. Some of these interconversions appear to be the result in the generation of spontaneous omni-mating strains. This phenomenon has now been quantitated and the distribution of mating-type loci in these "natural" amni-mating types determined.

Diploidy↗

PubMed2006

Mate location mechanism and phase-related mate preferences in solitarius desert locust, Schistocerca gregaria.

Mate location responses of male and female solitary-reared locusts that had either experienced no crowding or that had been crowded for varying periods were studied in a flatbed wind tunnel. Two hypotheses were explored: that both sexes of this phase of the locust participate in locating the other by using a combination of chemical and visual signals, and that individuals that experience some crowding (i.e., undergo varying levels of phase shift) can compete effectively with their solitary counterparts in mate location and mating. Our results confirm that both male and female solitarious locusts actively participate in mate location, although the former is the more aggressive partner. The responses of the insects are stronger when a visual cue is provided with the olfactory signal. Crowding of solitary-reared adults enhances their responsiveness to the other sex in the absence and presence of the visual cue. This phenomenon may constitute one of several mechanisms that are involved in recruiting solitary individuals into gregarizing groups and facilitating the spread of gregarious characters across a reproductively active solitarious population.

Animals↗

PubMed1995

Change of mate and mating competition between males of Schistosoma intercalatum and S. mansoni.

Previous studies on mating behaviour of Schistosoma intercalatum and S. mansoni, two human schistosomes which may overlap in parts of Africa, have shown that in mixed infections in mice there are no physiological barriers preventing heterospecific pairings. However, when choice is possible, matings occur preferentially between partners of the same species. In this paper, further experimental studies on mating behaviour of the two species were conducted. Sequential infections showed that heterospecific pairs of worms change partners to homospecific pairs when given the opportunity. The change of mate is a progressive process requiring up to, at least 8 weeks, and this phenomenon is due to the male worm seeking the appropriate female. S. mansoni males are better at pairing with females than S. intercalatum males, and they will change partner to pair with homologous females in preference to heterologous females whenever given the opportunity. Moreover, in the absence of S. mansoni female worms, unpaired S. mansoni male worms pull away female S. intercalatum from male S. intercalatum. It appears from this study that S. mansoni males are much more competitive than S. intercalatum males at pairing with females, and this is a disadvantage for S. intercalatum in situations of sympatry.

Animals↗

PubMed1997

The Chlamydomonas mating type plus fertilization tubule, a prototypic cell fusion organelle: isolation, characterization, and in vitro adhesion to mating type minus gametes.

In the biflagellated alga Chlamydomonas, adhesion and fusion of the plasma membranes of gametes during fertilization occurs via an actin-filled, microvillus-like cell protrusion. Formation of this approximately 3-microm-long fusion organelle, the Chlamydomonas fertilization tubule, is induced in mating type plus (mt+) gametes during flagellar adhesion with mating type minus (mt-) gametes. Subsequent adhesion between the tip of the mt+ fertilization tubule and the apex of a mating structure on mt- gametes is followed rapidly by fusion of the plasma membranes and zygote formation. In this report, we describe the isolation and characterization of fertilization tubules from mt+ gametes activated for cell fusion. Fertilization tubules were detached by homogenization of activated mt+ gametes in an EGTA-containing buffer and purified by differential centrifugation followed by fractionation on sucrose and Percoll gradients. As determined by fluorescence microscopy of samples stained with a fluorescent probe for filamentous actin, the method yielded 2-3 x 10(6) fertilization tubules/microg protein, representing up to a 360-fold enrichment of these organelles. Examination by negative stain electron microscopy demonstrated that the purified fertilization tubules were morphologically indistinguishable from fertilization tubules on intact, activated mt+ gametes, retaining both the extracellular fringe and the internal array of actin filaments. Several proteins, including actin as well as two surface proteins identified by biotinylation studies, copurified with the fertilization tubules. Most importantly, the isolated mt+ fertilization tubules bound to the apical ends of activated mt- gametes between the two flagella, the site of the mt- mating structure; a single fertilization tubule bound per cell, binding was specific for gametes, and fertilization tubules isolated from trypsin-treated, activated mt+ gametes did not bind to activated mt- gametes.

Animals↗

PubMed2003

Random mating with a finite number of matings.

Random mating is the null model central to population genetics. One assumption behind random mating is that individuals mate an infinite number of times. This is obviously unrealistic. Here we show that when each female mates a finite number of times, the effective size of the population is substantially decreased.

Animals↗

PubMed1976

Regulation of mating and meiosis in yeast by the mating-type region.

A supposed sporulation-deficient mutation of Saccharomyces cerevisiae is found to affect mating in haploids and in diploids, and to be inseparable from the mating-type locus by recombination. The mutation is regarded as a defective a allele and is designated a*. This is confirmed by its dominance relations in diploids, triploids, and tetraploids. Tetrad analysis of tetraploids and of their sporulating diploid progeny suggests the existence of an additional locus, RME, which regulates sporulation in yeast strains that can mate. Thus the recessive homozygous constitution rme/rm- enables the diploids a*/alpha, a/a*, and alpha/alpha to go through meiosis. Haploids carrying rme show apparent premeiotic DNA replication in sporulation conditions. This new regulatory locus is linked to the centromere of the mating-type chromosome, and its two alleles, rme and RME, are found among standard laboratory strains.

Alleles↗

PubMed1993

No reduction in the cost of mating for Drosophila melanogaster females mating with spermless males.

Drosophila melanogaster females can incur a cost of mating, manifested as a decrease in longevity and lifetime reproductive success. We investigated whether the cost of mating was a cost of storing and/or receiving sperm by using two types of males that do not transfer sperm (transformer pseudomales and the male offspring of homozygous tudor mothers). Females that were intermittently exposed to males that did and did not transfer sperm did not differ in lifespan, in the absence of any differences in other costly aspects of reproduction, showing that there was no cost to receiving sperm. There was a cost of mating with spermless males; this suggested a potential cost of receiving accessory fluid. However, it was not possible to distinguish this possibility from other explanations, e.g. female injury at mating and the transfer of parasites. The reasons why females continuously exposed to males remated more than was in their reproductive interests is discussed.

Animals↗