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Topic Review
Spermine in Prostate Cancer
Spermine, a member of polyamines, exists in all organisms and is essential for normal cell growth and function. It is highly expressed in the prostate compared with other organs and is detectable in urine, tissue, expressed prostatic secretions, and erythrocyte. A significant reduction of spermine level was observed in prostate cancer (PCa) tissue compared with benign prostate tissue, and the level of urinary spermine was also significantly lower in men with PCa. Decreased spermine level may be used as an indicator of malignant phenotype transformation from normal to malignant tissue in prostate.
  • 977
  • 25 May 2021
Topic Review
Spermine
In recent years, research on spermine (Spm) has turned up a lot of new information about this essential polyamine, especially as it is able to counteract damage from abiotic stresses. Spm has been shown to protect plants from a variety of environmental insults, but whether it can prevent the adverse effects of drought has not yet been reported. Drought stress increases endogenous Spm in plants and exogenous application of Spm improves the plants’ ability to tolerate drought stress. Spm's role in enhancing antioxidant defense mechanisms, glyoxalase systems, methylglyoxal (MG) detoxification, and creating tolerance for drought-induced oxidative stress is well documented in plants. However, the influences of enzyme activity and osmoregulation on Spm biosynthesis and metabolism are variable. Spm interacts with other molecules like nitric oxide (NO) and phytohormones such as abscisic acid, salicylic acid, brassinosteroids, and ethylene, to coordinate the reactions necessary for developing drought tolerance. This review focuses on the role of Spm in plants under severe drought stress. We have proposed models to explain how Spm interacts with existing defense mechanisms in plants to improve drought tolerance.
  • 1.0K
  • 23 Feb 2021
Topic Review
Spermatophyte Sesquiterpene Synthases
Sesquiterpenes are important defense and signal molecules for plants to adapt to the environment, cope with stress, and communicate with the outside world, and their evolutionary history is closely related to physiological functions. In this study, the information of plant sesquiterpene synthases (STSs) with identified functions were collected and sorted to form a dataset containing about 500 members. The phylogeny of spermatophyte functional STSs was constructed based on the structural comparative analysis to reveal the sequence–structure–function relationships. We propose the evolutionary history of plant sesquiterpene skeletons, from chain structure to small rings, followed by large rings for the first time and put forward a more detailed function-driven hypothesis. Then, the evolutionary origins and history of spermatophyte STSs are also discussed. In addition, three newly identified STSs CaSTS2, CaSTS3, and CaSTS4 were analyzed in this functional evolutionary system, and their germacrene D products were consistent with the functional prediction. This demonstrates an application of the structure-based phylogeny in predicting STS function. 
  • 647
  • 10 Aug 2021
Topic Review
Spermatogonial Stem Cells in Fish
Spermatogenesis is a continuous and dynamic developmental process, in which a single diploid spermatogonial stem cell (SSC) proliferates and differentiates to form a mature spermatozoon. Herein, we summarize the accumulated knowledge of SSCs and their distribution in the testes of teleosts.
  • 1.0K
  • 10 Jun 2021
Topic Review
Spermatogenesis and Male Fertility
Spermatogenesis is an extremely complex developmental process and involves the orderly differentiation of multiple types of spermatogenic cells, including mitotically proliferating spermatogonial cells, meiotically dividing spermatocytes, and spermatids that eventually mature into spermatozoa.
  • 672
  • 17 Feb 2022
Topic Review
Sperm Sex-Sorting
The utilization of sex-sorted sperm for artificial insemination and in-vitro fertilization is considered a valuable tool for improving production efficiency and optimizing reproductive management in farm animals, subsequently ensuring sufficient food resource for the growing human population. 
  • 1.0K
  • 29 Apr 2021
Topic Review
Sperm Proteins IZUMO1 and TMEM95 in Mammalian Fertilization
Gamete membrane fusion is a critical cellular event in sexual reproduction. In addition, the generation of knockout models has provided a powerful tool for testing the functional relevance of proteins thought to be involved in mammalian fertilization, suggesting IZUMO1 and TMEM95 (transmembrane protein 95) as essential proteins.
  • 484
  • 13 Apr 2022
Topic Review
Sperm in Honey Bee Drones
The quality of honey bee drone semen is relevant in different contexts, ranging from colony productivity to pathology, toxicology and biodiversity preservation. Despite its importance, considerably less knowledge is available on this subject for the honey bee when compared to other domestic animal species. A proper assessment of sperm quality requires a multiple testing approach which discriminates between the different aspects of sperm integrity and functionality. Most studies on drone semen quality have only assessed a few parameters, such as sperm volume, sperm concentration and/or sperm plasma membrane integrity.
  • 1.7K
  • 13 Jul 2021
Topic Review
Sperm DNA Oxidation
Sperm DNA Oxidation has destructive effects on sperm structures and functions, thus can result in male infertility. The particular composition of the sperm membrane, rich in polyunsaturated fatty acids, and the easy access of sperm DNA to oxidative damage due to sperm cell specific cytologic and metabolic features (no cytoplasm left and cells unable to mount stress responses) make it the cell type in metazoans most susceptible to oxidative damage. In particular, oxidative damage to the spermatozoa genome is an important issue and a cause of male infertility, usually associated with single- or double-strand paternal DNA breaks.
  • 504
  • 27 Jan 2021
Topic Review
Sperm Cryopreservation Protocol
The storage of frozen sperm samples from birds in Germoplasm Banks could be a way out for the conservation of thousands of threatened species. The cryopreserved samples could be later used in reintroduction projects. This technology also allows for the selection of individuals of genetic interest and the exchange of samples between distant locations. Although the sperm cryopreservation is greatly developed in domestic species, in birds it is still in its infancy. The objective of this study was optimize the cryopreservation protocol in a bird of prey, peregrine falcon (Falco peregrinus) which could be used as a model for other threats. Thus, the freezing/thawing protocol and the type and concentration of cryoprotectant were evaluated.
  • 843
  • 30 Oct 2020
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