Is the type of sexual process a generic characteristic?

2019 ◽  
pp. 190-193
Author(s):  
Olga I. Davidovich ◽  
Nickolai A. Davidovich
Keyword(s):  
Sexual Reproduction ◽  
Sexual Process ◽  
Pennate Diatoms

The study of sexual reproduction in members of the pennate diatoms of the genus Haslea (H. ostrearia, H. karadagensis, H. provincialis, H. crucigera, H. subagnita) showed that they all have the same type of sexual reproduction. Our and literature data suggest that the scheme of the process of sexual reproduction is a conservative generic characteristic.

Induction of conjugation in Mougeotia

1989 ◽  
Vol 67 (7) ◽  
pp. 2217-2218 ◽  
Author(s):  
H. Stabenau ◽  
W. Säftel
Keyword(s):  
Sexual Reproduction ◽  
Growth Medium ◽  
Nitrogen Supply ◽  
Sexual Process ◽  
University Of Göttingen ◽  
The University

The alga Mougeotia, strain 164.80, from the algae collection of the University of Göttingen, can be stimulated into sexual reproduction by decreasing the concentration of nitrate in the growth medium from 10−2 to 10−3 M. This effect could not be observed at any other concentration. To initiate the sexual process, cultures were illuminated with an intensity of 550 foot candles. Aeration of the cultures was absolutely necessary. Conjugation started 6 or 9 days after limitation of the nitrogen supply, depending on the CO2 content in the aeration mixture. From the characteristics observed during conjugation, strain 164.80 was identified to be Mougeotia scalaris Hassall.

scholarly journals Mating type specific transcriptomic response to sex inducing pheromone in the pennate diatom Seminavis robusta

2020 ◽  
Author(s):  
Gust Bilcke ◽  
Koen Van den Berge ◽  
Sam De Decker ◽  
Eli Bonneure ◽  
Nicole Poulsen ◽  
...  
Keyword(s):  
Sexual Reproduction ◽  
Mating Type ◽  
Target Genes ◽  
Specific Response ◽  
Pennate Diatom ◽  
Transcriptomic Response ◽  
Searching Behaviour ◽  
Cgmp Signaling ◽  
Phase Progression ◽  
Pennate Diatoms

AbstractSexual reproduction is a fundamental phase in the life cycle of most diatoms. Despite its role as a source of genetic variation, it is rarely reported in nature and its molecular foundations remain largely unknown. Here, we integrate independent transcriptomic datasets, in order to prioritize genes responding to sex inducing pheromones (SIPs) in the pennate diatom Seminavis robusta. We observe marked gene expression changes associated with SIP treatment in both mating types, including an inhibition of S-phase progression, chloroplast division, mitosis and cell wall formation. Meanwhile, meiotic genes are upregulated in response to SIP, including a sexually induced diatom specific cyclin (dsCyc). Our data further suggest an important role for reactive oxygen species, energy metabolism and cGMP signaling during the early stages of sexual reproduction. In addition, we identify several genes with a mating type specific response to SIP, and link their expression pattern with physiological responses such as the production of the attraction pheromone diproline and mate-searching behaviour in MT+. Combined, our results provide a model for early sexual reproduction in pennate diatoms and significantly expand the suite of target genes to detect sexual reproduction events in natural diatom populations.

Cortical positioning and the fate of oral structures during the sexual process in amicronucleate homopolar tandems of Paramecium

Development ◽  
1988 ◽  
Vol 102 (3) ◽  
pp. 587-594
Author(s):  
S.F. Ng
Keyword(s):  
Sexual Reproduction ◽  
Cell Lines ◽  
Low Frequency ◽  
Positional Information ◽  
Binary Fission ◽  
Transient Growth ◽  
Paramecium Tetraurelia ◽  
Growth Depression ◽  
Sexual Process

Paramecium tetraurelia normally resorbs the pre-existing oral apparatus (and develops a new one) during sexual reproduction. Violation of this rule was found in amicronucleate cell lines. These cell lines generated chains of two cells (homopolar tandems) at a low frequency, as a result of incomplete binary fission during a transient growth depression period following emicronucleation. In autogamous chains, the proter resorbed the pre-existing oral structures, while some of the ospisthes retained them. The oral structures in the opisthes of the chains were unusually close to the opisthes' anterior end. The ectopic location of these oral structures might account for their retention, formally understood in terms of the theory of positional information. It is suggested that nongenic factors, likely involving components of the rigid cortical matrix, are involved in the fixation of positional values.

Sexual reproduction of Entomoneis cf. paludosa (Bacillariophyta)

2019 ◽  
pp. 194-196
Author(s):  
Yulia A. Podunay ◽  
Nickolai A. Davidovich ◽  
Olga I. Davidovich
Keyword(s):  
Life Cycle ◽  
Sexual Reproduction ◽  
Pennate Diatom ◽  
Sexual Process

Sexual reproduction and the life cycle of the marine pennate diatom Entomoneis cf. paludosa are described. The reproduction in this species is characterized by morphological and behavioral isogamy. Two gametangia are involved in the sexual process, each of which produces two gametes.

The effect of sodium thiosulfate in a culture medium on the sexual reproduction of three species of Bacillariophyta

2021 ◽  
pp. 10-14
Author(s):  
Svetlana L. Polykova ◽  
Nickolai A. Davidovich ◽  
Olga I. Davidovich ◽  
Yuliia A. Podunai
Keyword(s):  
Sexual Reproduction ◽  
Culture Medium ◽  
Sodium Thiosulfate ◽  
Marine Water ◽  
Sexual Process ◽  
Clonal Cultures

It was studied the effect of sulfur in the form of sodium thiosulfate pentahydrate on the capability of clonal cultures of Pleurosigma sp., Toxarium undulatum, Pseudo-nitzschia calliantha to interbreed successfully and produce fertile offspring if they were cultivated in artificially prepared marine water (ESAW medium). Differences in the time of the beginning of the sexual process and the intensity of its passage for clones contained on ESAW with the addition of sodium thiasulfate and in the absence of it are shown.

scholarly journals Estimation of the propensity for sexual selection in a cyclical parthenogen

2020 ◽  
Author(s):  
David Duneau ◽  
Florian Altermatt ◽  
Jean-Baptiste Ferdy ◽  
Frida Ben-Ami ◽  
Dieter Ebert
Keyword(s):  
Sexual Selection ◽  
Sexual Reproduction ◽  
Sperm Competition ◽  
Indirect Evidence ◽  
Sperm Length ◽  
Cyclical Parthenogenesis ◽  
Single Female ◽  
Sexual Process ◽  
Different Populations ◽  
Firm Evidence

AbstractCyclical parthenogenesis is a widespread reproductive strategy in which organisms go through one or multiple rounds of clonal reproduction before sexual reproduction. Because sexual reproduction is typically less common than parthenogenesis in populations of the planktonic cladoceran Daphnia magna, it is not frequently studied. Here we examine the sexual process of D. magna and its relation to sexual selection in Daphnia rockpool populations by observing natural mating in these shallow habitats where sex generally occurs throughout the summer. Although microsatellite markers were found to reveal no evidence of disassortative mating or, thus, of inbreeding avoidance, body length and infection status did reveal assortative mating, suggesting sexual selection to act. When two males mated with a single female, the larger male was observed to remain longer, possibly giving it an advantage in sperm competition. Indirect evidence points at the brood pouch as the likely site of fertilization and thus, sperm competition. Sperm length was as variable within ejaculates as it was among males from different populations. Our data provide firm evidence that sexual selection is present in this species, most likely manifesting itself through a combination of female choice and male–male competition.

scholarly journals Pheromone Mediated Sexual Reproduction of Pennate Diatom Cylindrotheca closterium

2021 ◽  
Author(s):  
Franziska Klapper ◽  
Sien Audoor ◽  
Wim Vyverman ◽  
Georg Pohnert
Keyword(s):  
Sexual Reproduction ◽  
Cell Cycle Progression ◽  
Benthic Diatoms ◽  
Cycle Progression ◽  
Cylindrotheca Closterium ◽  
Mating Efficiency ◽  
Pheromone System ◽  
Ecological Success ◽  
Pennate Diatoms ◽  
Intertidal Environments

AbstractBenthic diatoms dominate primary production in marine subtidal and intertidal environments. Their extraordinary species diversity and ecological success is thought to be linked with their predominantly heterothallic sexual reproduction. Little is known about pheromone involvement during mating of pennate diatoms. Here we describe pheromone guided mating in the coastal raphid diatom Cylindrotheca closterium. We show that the two mating types (mt+ and mt−) have distinct functions. Similar to other benthic diatoms, mt+ cells are searching for the mt− cells to pair. To enhance mating efficiency mt− exudes an attraction pheromone which we proved by establishing a novel capillary assay. Further, two more pheromones produced by mt− promote the sexual events. One arrests the cell cycle progression of mt+ while the other induces gametogenesis of mt+. We suggest that C. closterium shares a functionally similar pheromone system with other pennate diatoms like Seminavis robusta and Pseudostaurosira trainorii which synchronize sexual events and mate attraction. Remarkably, we found no evidence of mt+ producing pheromones, which differentiates C. closterium from other pennates and suggests a less complex pheromone system in C. closterium.

scholarly journals Pheromone Mediated Sexual Reproduction of Pennate Diatom Cylindrotheca Closterium

2021 ◽  
Author(s):  
Franziska Klapper ◽  
Sien Audoor ◽  
Wim Vyverman ◽  
Georg Pohnert
Keyword(s):  
Sexual Reproduction ◽  
Cell Cycle Progression ◽  
Benthic Diatoms ◽  
Cycle Progression ◽  
Cylindrotheca Closterium ◽  
Mating Efficiency ◽  
Pheromone System ◽  
Ecological Success ◽  
Pennate Diatoms ◽  
Intertidal Environments

Abstract Benthic diatoms dominate primary production in marine subtidal and intertidal environments. Their extraordinary species diversity and ecological success is thought to be linked with their motility and predominantly heterothallic sexual reproduction. Little is known about pheromone involvement during mating of pennate diatoms. Here we describe pheromone guided mating in the coastal raphid diatom Cylindrotheca closterium. We show that the two mating types (mt+ and mt¯) have distinct functions. Similar to other benthic diatoms, mt+ cells are searching for the mt¯ cells to pair. To enhance mating efficiency mt¯ exudes an attraction pheromone, which we proved by establishing a novel capillary assay. Further, two more pheromones produced by mt¯ promote the sexual events. One arrests the cell cycle progression of mt+ while the other induces gametogenesis of mt+. We suggest that C. closterium shares a functionally similar pheromone system with other pennate diatoms like Seminavis robusta and Pseudostaurosira trainorii which synchronize sexual events and mate attraction. Remarkably, we found no evidence of mt+ producing pheromones, which differentiates C. closterium from other pennates and suggests a less complex pheromone system in C. closterium.

Elimination of altered karyotypes by sexual reproduction preserves species identity

Genome ◽  
2007 ◽  
Vol 50 (5) ◽  
pp. 517-524 ◽  
Author(s):  
Henry H.Q. Heng
Keyword(s):  
Genetic Diversity ◽  
Sexual Reproduction ◽  
Cancer Cells ◽  
Evolutionary Biology ◽  
Genetic Recombination ◽  
Deleterious Mutations ◽  
Species Identity ◽  
Sexual Process ◽  
Controlled Reproduction ◽  
Chromosome Level

Resolving the persistence of sexual reproduction despite its overwhelming costs (known as the paradox of sex) is one of the most persistent challenges of evolutionary biology. In thinking about this paradox, the focus has traditionally been on the evolutionary benefits of genetic recombination in generating offspring diversity and purging deleterious mutations. The similarity of pattern between evolution of organisms and evolution among cancer cells suggests that the asexual process generates more diverse genomes owing to less controlled reproduction systems, while sexual reproduction generates more stable genomes because the sexual process can serve as a mechanism to “filter out” aberrations at the chromosome level. Our reinterpretation of data from the literature strongly supports this hypothesis. Thus, the principal consequence of sexual reproduction is the reduction of drastic genetic diversity at the genome or chromosome level, resulting in the preservation of species identity rather than the provision of evolutionary diversity for future environmental challenges. Genetic recombination does contribute to genetic diversity, but it does so secondarily and within the framework of the chromosomally defined genome.

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