The role of the cytoplasm in antigen determination in Paramecium aurelia

1958 ◽  
Vol 148 (932) ◽  
pp. 308-314 ◽  
Keyword(s):  
Life Cycle ◽  
Male And Female ◽  
Cytoplasmic Factors ◽  
Antigen Determination ◽  
Suitable Organism

Paramecium, because of its peculiar life cycle, is an unusually suitable organism for a study of the role of the cytoplasm in variation and development. During conjugation there is a reciprocal interchange of gamete nuclei, followed by fusion of ‘male’ and ‘female’ nuclei in each partner, but there is usually no significant passage of cytoplasm between the mates. After conjugation, therefore, each of the ex-conjugants contains identical sets of genes, but may differ cytoplasmically, if the cytoplasms of the conjugants had been different. Making use of this situation, paramecium workers, led by Dr T. M. Sonneborn, have studied the nuclear and cytoplasmic factors involved in the control of several different kinds of hereditary trait. I wish to stress here, however, that there is no overall uniformity amongst these systems. For example, the killer and antigen systems of paramecium are totally different. By contrast with the extraordinary regularity of the Mendelian system in different groups of organisms, cytoplasmic factors—in the very few cases where they have been thoroughly studied—are extremely diverse. Generalizing from one example to another is, therefore, unwise.

Schistosoma mansoni male–female interactions

2004 ◽  
Vol 82 (2) ◽  
pp. 357-374 ◽  
Author(s):  
Philip T LoVerde ◽  
Edward G Niles ◽  
Ahmed Osman ◽  
Wenjie Wu
Keyword(s):  
Life Cycle ◽  
Schistosoma Mansoni ◽  
Egg Production ◽  
Reproductive Development ◽  
Host Factors ◽  
Complex Life Cycle ◽  
Morphological Observation ◽  
Male Worm ◽  
Male And Female

Schistosome parasites are muticellular eucaryotic organisms with a complex life cycle that involves mammalian and snail hosts. Unlike other trematode parasites, schistosomes (along with the Didymozoidae) have evolved separate sexes or dioecy. Sex is determined by a chromosomal mechanism. The dioecious state created an opportunity for the sexes to play a role in schistosome evolution that has resulted in an interesting interplay between the sexes. The classical observation, made more than 50 years ago, is that female schistosomes do not develop unless a male worm is present. Studies up through the 1990s focused on dissecting the role of the sexes in mate attraction, mate choice, mating behavior, female growth, female reproductive development, egg production, and other sex-evolved functions. In the mid-1980s, studies began to address the molecular events of male–female interactions. The classic morphological observation that female schistosomes do not complete reproductive development unless a male worm is present has been redefined in molecular terms. The male by an unknown mechanism transduces a signal that regulates female gene expression in a stage-, tissue-, and temporal-specific manner. A number of female-specific genes have been identified, along with signaling pathways and nuclear receptors, that play a role in female reproductive development. In addition, a number of host factors such as cytokines have also been demonstrated to affect adult male and female development and egg production. This review focuses on the biological interactions of the male and female schistosome and the role of parasite and host factors in these interactions as they contribute to the life cycle of Schistosoma mansoni.

ASPECTS IN BUILDING A COMPANY WEB-SITE AND ITS ROLE FOR THE DEVELOPMENT OF BUSINESS

2018 ◽  
pp. 117-124
Author(s):  
Petar Halachev ◽  
Victoria Radeva ◽  
Albena Nikiforova ◽  
Miglena Veneva
Keyword(s):  
Life Cycle ◽  
Web Site ◽  
The Internet ◽  
A Company ◽  
The Web ◽  
Design Construction ◽  
Made In ◽  
Site Types

This report is dedicated to the role of the web site as an important tool for presenting business on the Internet. Classification of site types has been made in terms of their application in the business and the types of structures in their construction. The Models of the Life Cycle for designing business websites are analyzed and are outlined their strengths and weaknesses. The stages in the design, construction, commissioning, and maintenance of a business website are distinguished and the activities and requirements of each stage are specified.

scholarly journals Role of Virally-Encoded Deubiquitinating Enzymes in Regulation of the Virus Life Cycle

2021 ◽  
Vol 22 (9) ◽  
pp. 4438
Author(s):  
Jessica Proulx ◽  
Kathleen Borgmann ◽  
In-Woo Park
Keyword(s):  
Immune Response ◽  
Life Cycle ◽  
Deubiquitinating Enzyme ◽  
Deubiquitinating Enzymes ◽  
Antiviral Immune Response ◽  
Cellular Processes ◽  
Virus Life Cycle ◽  
Infected Cells ◽  
Dependent Processes

The ubiquitin (Ub) proteasome system (UPS) plays a pivotal role in regulation of numerous cellular processes, including innate and adaptive immune responses that are essential for restriction of the virus life cycle in the infected cells. Deubiquitination by the deubiquitinating enzyme, deubiquitinase (DUB), is a reversible molecular process to remove Ub or Ub chains from the target proteins. Deubiquitination is an integral strategy within the UPS in regulating survival and proliferation of the infecting virus and the virus-invaded cells. Many viruses in the infected cells are reported to encode viral DUB, and these vial DUBs actively disrupt cellular Ub-dependent processes to suppress host antiviral immune response, enhancing virus replication and thus proliferation. This review surveys the types of DUBs encoded by different viruses and their molecular processes for how the infecting viruses take advantage of the DUB system to evade the host immune response and expedite their replication.

scholarly journals Cysteine-Rich Hydrophobin Gene Family: Genome Wide Analysis, Phylogeny and Transcript Profiling in Cordyceps militaris

2021 ◽  
Vol 22 (2) ◽  
pp. 643
Author(s):  
Xiao Li ◽  
Fen Wang ◽  
Yanyan Xu ◽  
Guijun Liu ◽  
Caihong Dong
Keyword(s):  
Life Cycle ◽  
Pathogenic Fungi ◽  
Class Ii ◽  
Cordyceps Militaris ◽  
Transcript Profiling ◽  
Saprotrophic Fungi ◽  
Genome Wide Analysis ◽  
Genome Wide ◽  
Encoding Genes

Hydrophobins are a family of small secreted proteins found exclusively in fungi, and they play various roles in the life cycle. In the present study, genome wide analysis and transcript profiling of the hydrophobin family in Cordyceps militaris, a well-known edible and medicinal mushroom, were studied. The distribution of hydrophobins in ascomycetes with different lifestyles showed that pathogenic fungi had significantly more hydrophobins than saprotrophic fungi, and class II members accounted for the majority. Phylogenetic analysis of hydrophobin proteins from the species of Cordyceps s.l. indicated that there was more variability among the class II members than class I. Only a few hydrophobin-encoding genes evolved by duplication in Cordyceps s.l., which was inconsistent with the important role of gene duplication in basidiomycetes. Different transcript patterns of four hydrophobin-encoding genes during the life cycle indicated the possible different functions for each. The transcripts of Cmhyd2, 3 and 4 can respond to light and were related with the photoreceptors. CmQHYD, with four hydrophobin II domains, was first found in C. militaris, and multi-domain hydrophobins were only distributed in the species of Cordycipitaceae and Clavicipitaceae. These results could be helpful for further function research of hydrophobins and could provide valuable information for the evolution of hydrophobins.

Sign in / Sign up

Export Citation Format

Share Document