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PubMed1979

Mating pheromones of Saccharomyces kluyveri: pheromone interactions between Saccharomyces kluyveri and Saccharomyces cerevisiae.

Saccharomyces kluyveri is a heterothallic yeast with two allelic mating types denoted as a-k and alpha-k by analogy with Saccharomyces cerevisiae and from the work described here. S. kluyveri produces mating pheromones analogous to those of S. cerevisiae, but which appear to have different specificity. S. kluyveri thus differs from S. cerevisiae, Hansenula wingei, and Schizosaccharomyces pombe in that it exhibits both strong constitutive agglutination and mating pheromones. alpha-k cells produce a pheromone ("alpha-k-factor") which causes a-k cells to arrest in the G1 phase of the cell cycle and to undergo a morphological change. After a period of time dependent on the concentration of alpha-k-factor, cells exposed to the factor resume cell division. alpha-k-factor has no effect on a-k/alpha-k diploids or on alpha-k cells, but at high concentration does induce G1 arrest of S. cerevisiaea cells (a-c). a-k cells produce a pheromone ("a-k-factor") which causes alpha-k cells to exhibit a morphological change. In addition, a-k cells exhibit the Bar phenotype with respect to alpha-k-factor. Partially purified preparations of S. cerevisiae alpha-factor are more active in inducing G1 arrest of a-k cells than of a-c cells. A more purified preparation of alpha-c-factor is less active against a-k cells than a-c cells, suggesting that an additional factor (KRE, kluyveri response enhancer) may be lost during purification. Attempts to mate S. kluyveri and S. cerevisiae cells by prototroph selection and by cell-to-cell mating have been unsuccessful with all combinations of mating types. Thus, S. cerevisiae and S. kluyveri are incompatible for mating even though their pheromones exhibit some physiological cross-reaction.

Crosses, Genetic↗

PubMed1983

Extracellular suppression allows mating by pheromone-deficient sterile mutants of Saccharomyces cerevisiae.

MAT alpha haploids with mutations in the STE13 or KEX2 gene, and MATa haploids with mutations in the STE6 or STE14 gene, do not mate with wild-type cells of the opposite mating type. We found that such mutants were able to mate with partners that carry mutations (sst1 and sst2) that cause cells to be supersensitive to yeast mating pheromone action. Mating ability of MAT alpha ste13 and MAT alpha kex2 mutants could also be restored by adding normal MAT alpha cells to mating mixtures or by adding just the appropriate purified pheromone (alpha-factor). Therefore, the mating deficiencies caused by the ste13 and kex2 lesions, and by inference, the ste6 and ste14 mutations, appear to result only from secretion of an insufficient amount of pheromone or a nonfunctional pheromone.

Animals↗

PubMed1963

STEROLS AS COMPONENTS IN THE MATING REACTION OF HANSENULA WINGEI.

Hunt, D. E. (Charles V. Chapin Hospital, Providence, R.I.) and P. L. Carpenter. Sterols as components in the mating reaction of Hansenula wingei. J. Bacteriol. 86:845-847. 1963.-Agglutinative mating strains 5 and 21 of the yeast Hansenula wingei did not agglutinate after the cells of these two strains were treated with nystatin. The agglutination-inhibiting action of this antibiotic could not be reversed by washing, or heating, or washing and heating the cells. When cells of the two mating types, which had not been treated with nystatin, were heated and washed three times with a chloroform-ethanol (1:3, v/v) solution, the agglutination reaction was reduced significantly. If unwashed cells of mating strain 5 were tested for agglutination with chloroform-ethanol washed cells of mating strain 21, normal agglutination occurred readily. The reciprocal of this agglutination test also resulted in normal agglutination. Evidence is presented that the factor(s) required for the mating reaction in H. wingei can be supplied by either strain, and sterols or related compounds have an active role in the mating reaction.

Agglutination↗

PubMed1969

Inheritance of mating factors in nocardial recombinants.

The segregation of mating loci with other unselected genes was analyzed in recombinants obtained from matings of Nocardia canicruria and N. erythropolis. The loci C/c and E/e control nocardial compatibility. Four mating genotype combinations were observed: cE, Ce, CE, and ce. Strains of N. erythropolis bear the genotype cE and strains of N. canicruria bear the Ce alleles. The CE recombinant mating type is capable of mating with both organisms, whereas the ce-containing recombinant is nonfertile. The E locus was found to segregate with StrA1 (streptomycin-resistance gene) on the N. erythropolis linkage group. The C locus appeared linked to PurB2 (purine-requiring gene) on the N. canicruria linkage group. A few observed recombinants were capable of further segregation of unselected characters after colonial purification, suggesting a possible heterogenomic condition or multiple rounds of mating. Prior treatment of recombinants with acriflavine failed to alter their compatibility or the frequency at which recombinants were recovered. The segregation pattern of the mating loci allowed for specific recombinant class types to be compatible.

Alleles↗

PubMed1997

Coordination of the mating and cell integrity mitogen-activated protein kinase pathways in Saccharomyces cerevisiae.

Mating pheromone stimulates a mitogen-activated protein (MAP) kinase activation pathway in Saccharomyces cerevisiae that induces cells to differentiate and form projections oriented toward the gradient of pheromone secreted by a mating partner. The polarized growth of mating projections involves new cell wall synthesis, a process that relies on activation of the cell integrity MAP kinase, Mpk1. In this report, we show that Mpk1 activation during pheromone induction requires the transcriptional output of the mating pathway and protein synthesis. Consequently, Mpk1 activation occurs subsequent to the activation of the mating pathway MAP kinase cascade. Additionally, Spa2 and Bni1, a formin family member, are two coil-coil-related proteins that are involved in the timing and other aspects of mating projection formation. Both proteins also affect the timing and extent of Mpk1 activation. This correlation suggests that projection formation comprises part of the pheromone-induced signal that coordinates Mpk1 activation with mating differentiation. Stimulation of Mpk1 activity occurs through the cell integrity phosphorylation cascade and depends on Pkc1 and the redundant MAP/Erk kinases (MEKs), Mkk1 and Mkk2. Surprisingly, Mpk1 activation by pheromone was only partially impaired in cells lacking the MEK kinase Bck1. This Bck1-independent mechanism reveals the existence of an alternative activator of Mkk1/Mkk2 in some strain backgrounds that at least functions under pheromone-induced conditions.

Calcium-Calmodulin-Dependent Protein Kinases↗

PubMed1998

Cln3-associated kinase activity in Saccharomyces cerevisiae is regulated by the mating factor pathway.

The Saccharomyces cerevisiae cell cycle is arrested in G1 phase by the mating factor pathway. Genetic evidence has suggested that the G1 cyclins Cln1, Cln2, and Cln3 are targets of this pathway whose inhibition results in G1 arrest. Inhibition of Cln1- and Cln2-associated kinase activity by the mating factor pathway acting through Far1 has been described. Here we report that Cln3-associated kinase activity is inhibited by mating factor treatment, with dose response and timing consistent with involvement in cell cycle arrest. No regulation of Cln3-associated kinase was observed in a fus3 kss1 strain deficient in mating factor pathway mitogen-activated protein (MAP) kinases. Inhibition occurs mainly at the level of specific activity of Cln3-Cdc28 complexes. Inhibition of the C-terminally truncated Cln3-1-associated kinase is not observed; such truncations were previously identified genetically as causing resistance to mating factor-induced cell cycle arrest. Regulation of Cln3-associated kinase specific activity by mating factor treatment requires Far1. Overexpression of Far1 restores inhibition of C-terminally truncated Cln3-1-associated kinase activity. G2/M-arrested cells are unable to regulate Cln3-associated kinase, possibly because of cell cycle regulation of Far1 abundance. Inhibition of Cln3-associated kinase activity by the mating factor pathway may allow this pathway to block the earliest step in normal cell cycle initiation, since Cln3 functions as the most upstream G1-acting cyclin, activating transcription of the G1 cyclins CLN1 and CLN2 as well as of the S-phase cyclins CLB5 and CLB6.

Cell Cycle↗

PubMed2000

The G-protein beta subunit GPB1 is required for mating and haploid fruiting in Cryptococcus neoformans.

Cryptococcus neoformans is an opportunistic fungal pathogen with a defined sexual cycle. The gene encoding a heterotrimeric G-protein beta subunit, GPB1, was cloned and disrupted. gpb1 mutant strains are sterile, indicating a role for this gene in mating. GPB1 plays an active role in mediating responses to pheromones in early mating steps (conjugation tube formation and cell fusion) and signals via a mitogen-activated protein (MAP) kinase cascade in both MATalpha and MATa cells. The functions of GPB1 are distinct from those of the Galpha protein GPA1, which functions in a nutrient-sensing cyclic AMP (cAMP) pathway required for mating, virulence factor induction, and virulence. gpb1 mutant strains are also defective in monokaryotic fruiting in response to nitrogen starvation. We show that MATa cells stimulate monokaryotic fruiting of MATalpha cells, possibly in response to mating pheromone, which may serve to disperse cells and spores to locate mating partners. In summary, the Gbeta subunit GPB1 and the Galpha subunit GPA1 function in distinct signaling pathways: one (GPB1) senses pheromones and regulates mating and haploid fruiting via a MAP kinase cascade, and the other (GPA1) senses nutrients and regulates mating, virulence factors, and pathogenicity via a cAMP cascade.

Amino Acid Sequence↗

PubMed1989

Effect of fall mating on ovarian development in the red-sided garter snake.

Although spring mating is an important factor in initiating vitellogenesis in female red-sided garter snakes (Thamnophis sirtalis parietalis), some females can become vitellogenic without having mated in the spring. Two hypotheses have been proposed to explain this phenomenon: 1) long-term storage of copulatory stimuli from mating the previous fall, or 2) additional cue(s) overcoming the lack of mating to stimulate vitellogenesis. Through oviductal biopsy, the presence of sperm in females returning to the hibernaculum in the fall was assessed. Laparotomies performed just before and 6 wk after hibernation indicated that although fall mating may stimulate slight ovarian development in the fall, there appears to be no effect of fall mating on spring ovarian recrudescence. Spring mating seems to be the most important factor in determining ovarian maturation. Therefore, it appears that there is no long-term storage of copulatory cues and that other as yet unknown cues are responsible for initiating vitellogenesis in spring unmated females.

Animals↗

PubMed2003

c-FOS expression in the forebrain after mating in the female rat is altered by adrenalectomy.

In rats of both sexes, mating stimulates neuronal activity in forebrain areas that are also activated by stress. Hypothalamic cells in the arcuate (ARC) and paraventricular (PVN) nuclei synthesize hormones or peptides whose levels are altered by adrenalectomy. In this experiment, we examined whether the mating-induced expression of c-FOS in the forebrain is altered by adrenalectomy (Adx) in female rats. Ovariectomized females were adrenalectomized (Adx) or sham-operated (Sham), hormone-primed and mated 2 weeks after surgery. They received 15 intromissions (15I), 5 intromissions (5I) or 15 mounts without intromission (MO) from a male or were taken directly from their home cage (HC). Two hours after mating, rats were perfused with paraformaldehyde and their brains were collected and stained immunocytochemically for FOS protein. FOS-immunoreactive (FOS-IR) cells in the posterodorsal medial amygdala (MePD), bed nucleus of stria terminalis (BNST), ventromedial hypothalamus (VMH), medial preoptic area (mPOA), ARC and PVN were counted bilaterally. In Sham animals, intromissions produced significant increases in FOS above HC levels. In Adx animals, mating increased FOS activity in all areas. However, responses to 5I and 15I differed between Sham and Adx groups. In all areas, Shams showed either the highest FOS response following 15I or levels which were equivalent after 5I and 15I. In Adx animals, the greatest number of FOS-positive cells occurred after 5I, with the 15I group showing significant suppression of FOS below 5I levels in the VMH, mPOA, ARC and PVN. These results demonstrate that the adrenal modulates FOS responses to mating in the female rat and suggest that adrenal secretory products normally may decrease sensitivity to low levels of mating stimulation. These effects may be due to increased corticotropin-releasing hormone (CRH) or beta-endorphin in the hypothalamus after adrenalectomy.

Adrenal Glands↗

PubMed2004

Adaptation of a South American malaria vector to laboratory colonization suggests faster-male evolution for mating ability.

BACKGROUND: Anopheles (Nyssorhynchus) albitarsis (Diptera: Culicidae) is one of the very few South American mosquito vectors of malaria successfully colonized in the laboratory. These vectors are very hard to breed because they rarely mate in artificial conditions. A few years ago a free-mating laboratory colony of An. albitarsis sensu stricto was established after about 30 generations of artificial-mating. To begin to understand the process of adaptation of these malaria vectors to the laboratory we have compared the insemination rates of colony mosquitoes to those from the original population in both artificial and free-mating crosses. We also carried out crossing experiments between the two types of mosquitoes for a preliminary analysis of the genetic basis of such adaptation. RESULTS: We show that, compared to the original population, colony males but not females have increased their insemination rates in the laboratory in both types of mating, suggesting that faster-male evolution of mating ability might have occurred during the colonization process. CONCLUSIONS: The results are consistent with the faster-male theory, which predicts that sexual selection will cause faster rates of evolution of genes expressed in males. The data also suggests that attempts to colonize other South American malaria mosquitoes will be more successful if special attention is given to the male ability to mate in a confined space.

Acclimatization↗

PubMed2003

Observations on the swarming and mating behaviour of Anopheles funestus from southern Mozambique.

BACKGROUND: Control of malaria by the release of genetically modified mosquitoes refractory to transmission is now becoming a possibility. In many areas of Africa, Anopheles gambiae is found together with an equally important vector, An. funestus. Given their sympatry and the likelihood of a similar mating period some aspects of the mating behaviour of An. gambiae s.l. and An. funestus are likely to differ. We therefore attempted to characterise the swarming behaviour of An. funestus and to determine if any aspects of the observed behaviour differed from that recorded for the M form of An. gambiae from São Tomé. METHODS: In March - May 2002 the swarming, mating, house exiting and resting behaviour of Anopheles funestus was studied by direct observation in Mozambique. Swarming males and insects in copula were collected by sweep net. Wing lengths of males collected resting, exiting houses, swarming and mating were measured and the wingbeat frequency distribution of individual insects, in free flight confined inside netting covered paper cups, was also determined. RESULTS: Mono-specific swarms occurred at sunset in relatively open areas close to houses used for resting. Mating pairs were seen 11 +/- 3.7 min after the start of swarming. The number of total pairs observed being inversely proportional to the time difference between the start of swarming and the first pairing. The great majority of females mated before feeding. Male or female size did not appear to affect mating success or other behaviours. During the study, ambient temperatures decreased and female, but not male, wing size increased. At 516 Hz, the flight tone of female An. funestus was similar to the 497 Hz of the local An. gambiae. Males dispersed if light or dark artificial horizontal markers were placed underneath naturally occurring swarms. CONCLUSION: Differential response to markers would be sufficient for swarming in An. funestus and An. gambiae s.l. to occur in distinct sites.

Activity Cycles↗

PubMed2001

Development of an optimized interaction-mating protocol for large-scale yeast two-hybrid analyses.

BACKGROUND: Protein-protein interactions have decisive roles in almost all aspects of the structural and functional organization of cells. But in spite of the increasing amount of complete genome sequence data, the ability to predict protein function from sequences alone is limited. Therefore comprehensive analysis of protein-protein interactions, as derived from the yeast two-hybrid mating system, will yield valuable information for functional biology on a proteomic scale. RESULTS: We have developed an optimized interaction mating protocol for the yeast two-hybrid system, which gives increased mating efficiencies. This significantly reduces the effort and cost of cDNA library screening and allows multiple parallel approaches. Improved preincubation conditions before mating, and optimal cell densities and cell ratios enable almost quantitative mating of the yeast cells carrying the cDNA library. We have proved the applicability of this technology using 20 bait proteins to screen an Arabidopsis thaliana cDNA library, in spite of bait-dependent variations in mating efficiency. CONCLUSIONS: The improved yeast two-hybrid interaction-mating protocol presented here allows the multiple parallel screening of cDNA libraries. It can be carried out without specialized equipment and has the potential to be standardized and automated.

Arabidopsis↗

PubMed1997

Sexually dimorphic processing of somatosensory and chemosensory inputs to forebrain luteinizing hormone-releasing hormone neurons in mated ferrets.

The ferret is a reflexively ovulating species in which mating induces a preovulatory LH surge in the estrous female but significantly decreases LH secretion in the breeding male. This sexually dimorphic hormonal response is reflected in a sex difference in Fos-like immunoreactivity (Fos-IR) in forebrain LHRH and non-LHRH neurons after mating. We used dual immunocytochemistry for Fos and LHRH to determine whether the sex dimorphism occurs in the initial detection and transmission or in the central processing of sensory stimuli associated with mating? We also assessed the ability of chemosensory cues alone to augment neuronal Fos-IR in the ferret forebrain. Breeding male and female ferrets were paired, whereupon the male partner achieved an intromission lasting for 16-90 min. Mated male and female subjects were always perfused 90 min after the onset of the male's intromission. Additional male and female subjects were placed alone in a cage in which an opposite sex ferret in breeding condition had been housed for 48 h. Other control ferrets were placed alone in a clean cage. Chemosensory-stimulated and unpaired control subjects were perfused 90 min after being placed in their respective cages. In both sexes mating augmented neuronal Fos-IR in the granular layer of the main olfactory bulb, the caudal thalamic central tegmental field, and the medial amygdala, regions situated early in the putative input pathway to mediobasal hypothalamic LHRH neurons. Neuronal Fos-IR was also increased in these same forebrain regions (the central tegmental field excluded) in both sexes after exposure to chemosensory cues alone. However, more central components of this input pathway, including the preoptic area, the bed nucleus of the stria terminalis, and the ventrolateral portion of the ventromedial hypothalamus as well as the mediobasal hypothalamic LHRH neurons themselves were activated by mating only in the female. In estrous females, exposure only to chemosensory stimuli from a breeding male augmented Fos-IR in the preoptic area and the ventrolateral portion of the ventromedial hypothalamus, but not in the bed nucleus of the stria terminalis or mediobasal hypothalamic LHRH neurons. In breeding males, exposure only to chemosensory cues from an estrous female failed to affect Fos-IR in any of these proximal components of the input pathway or in LHRH neurons themselves. These results suggest that the sex dimorphism in mating-induced LH secretion reflects a sex difference in the central processing of genital-somatosensory stimuli and possibly of chemosensory inputs as well.

Animals↗

PubMed2003

Enhanced cost of mating in female sterile mutants of Drosophila melanogaster.

In Drosophila females, mating is known to cause a reduction in life span, which is referred to as 'the cost of mating'. Since mating enhances oogenesis and oviposition, the cost of mating may be regarded as a trade-off between reproduction and longevity. We examined whether the cost of mating exists in mutant females that are unable to produce eggs. Three different mutant alleles of ovarian tumors (otu) and an allele of dunce (dnc(M11)) of Drosophila melanogaster were used to sterilize females. For all the female sterile mutants tested, mating dramatically decreased the life span of homozygous sterile females. Even more extreme shortening of life spans were observed when the sex peptide gene (Acp70A) was expressed in homozygous otu females, though they were virgin, indicating that the shortening in life span is due to seminal factors. These results indicate that the cost of mating is greater in females defective in oogenesis than that in normally fertile females.

Animals↗

PubMed2006

Resistance evolution to Bt crops: predispersal mating of European corn borers.

Over the past decade, the high-dose refuge (HDR) strategy, aimed at delaying the evolution of pest resistance to Bacillus thuringiensis (Bt) toxins produced by transgenic crops, became mandatory in the United States and is being discussed for Europe. However, precopulatory dispersal and the mating rate between resident and immigrant individuals, two features influencing the efficiency of this strategy, have seldom been quantified in pests targeted by these toxins. We combined mark-recapture and biogeochemical marking over three breeding seasons to quantify these features directly in natural populations of Ostrinia nubilalis, a major lepidopteran corn pest. At the local scale, resident females mated regardless of males having dispersed beforehand or not, as assumed in the HDR strategy. Accordingly, 0-67% of resident females mating before dispersal did so with resident males, this percentage depending on the local proportion of resident males (0% to 67.2%). However, resident males rarely mated with immigrant females (which mostly arrived mated), the fraction of females mating before dispersal was variable and sometimes substantial (4.8% to 56.8%), and there was no evidence for male premating dispersal being higher. Hence, O. nubilalis probably mates at a more restricted spatial scale than previously assumed, a feature that may decrease the efficiency of the HDR strategy under certain circumstances, depending for example on crop rotation practices.

Animals↗

PubMed2004

The quantitative genetic basis of male mating behavior in Drosophila melanogaster.

Male mating behavior is an important component of fitness in Drosophila and displays segregating variation in natural populations. However, we know very little about the genes affecting naturally occurring variation in mating behavior, their effects, or their interactions. Here, we have mapped quantitative trait loci (QTL) affecting courtship occurrence, courtship latency, copulation occurrence, and copulation latency that segregate between a D. melanogaster strain selected for reduced male mating propensity (2b) and a standard wild-type strain (Oregon-R). Mating behavior was assessed in a population of 98 recombinant inbred lines derived from these two strains and QTL affecting mating behavior were mapped using composite interval mapping. We found four QTL affecting male mating behavior at cytological locations 1A;3E, 57C;57F, 72A;85F, and 96F;99A. We used deficiency complementation mapping to map the autosomal QTL with much higher resolution to five QTL at 56F5;56F8, 56F9;57A3, 70E1;71F4, 78C5;79A1, and 96F1;97B1. Quantitative complementation tests performed for 45 positional candidate genes within these intervals revealed 7 genes that failed to complement the QTL: eagle, 18 wheeler, Enhancer of split, Polycomb, spermatocyte arrest, l(2)05510, and l(2)k02206. None of these genes have been previously implicated in mating behavior, demonstrating that quantitative analysis of subtle variants can reveal novel pleiotropic effects of key developmental loci on behavior.

Animals↗

PubMed1995

[Effects of feed and mating age on reproductive performance in Syrian hamsters].

In order to utilize Syrian hamsters in selection experiments, we investigated desirable conditions of feed and mating age for reproduction in females. Hamsters were subdivided into two groups, raised on pellet feed for herbivores (ZC-2) and breeding (MB-1), respectively. Half of the hamsters in each group were switched to the other feed, respectively, after mating. They were mated at 8 or 12 weeks of age. In the group that has been fed on ZC-2 before mating and MB-1 after mating, there was significantly more females giving birth and weaning, and exhibited the largest litter size and litter weight at 3 weeks of age (P < 0.01). The hamsters of the groups mated at 12 weeks of age exhibited a higher percentage of females giving birth and litter size and litter weight at birth than those at 8 weeks of age, but that was no significant difference in litter size and litter weight at 3 weeks of age. We conclude that Syrian hamsters raised by fibrous feed before mating gave optimal reproductive performance.

Aging↗

PubMedDate not supplied

Influence of mating on ovarian follicle development in Triatoma infestans (Klug, 1834).

This work examines the influence of mating on ovarian follicle development in Triatoma infestans. The observations were carried out on both virgin and mated females, which were killed at various times after their emergence. There was no difference in the ovarian development of both experimental groups during the first gonadotrophic cycle. By the 7th day mated females as well as virgin females showed vitellogenic oocytes. The coriogenesis and ovulation process began on the 13th day after imaginal moulting. However we could observe that egg-laying was dependent on mating. Mated females laid eggs whereas virgin females did not lay eggs. However ovarian production was significantly greater in the mated females. It is suggested that in T. infestans mating stimulates egg-laying but it does no influence the oogenesis and ovulation process.

Animals↗