Search results for "Sperm"
showing 10 items of 658 documents
Polyamine conjugates of stigmasterol.
2012
Abstract Three new polyamine conjugates with stigmasterol [(3β,22 E )-stigmasta-5,22-dien-3-ol] were synthesized and subjected to basic antimicrobial and cytotoxic tests. The conjugate derived from spermine, (3β,22 E )-stigmasta-5,22-dien-3-yl 4(12-amino-4,9-diaza-dodecylamino)-4-oxobutanoate ( 5c ), displayed considerable antimicrobial activity on Staphylococcus aureus at low concentration (50 μg mL −1 ). The cytotoxic activity was tested on cells of human T-lymfoblastic leukemia (IC 50 = 35.8 ± 10.3 μM ( 5c ) and IC 50 = 35.9 ± 5.7 μM ( 5b )) and normal human fibroblasts (IC 50 = 38.0 ± 2.8 μM ( 5c ) and IC 50 = 45.5 ± 1.9 μM ( 5b )). Conjugate 5a displayed no activity in both tests.
A Primary Evaluation of Potential Small-Molecule Inhibitors of the Astacin Metalloproteinase Ovastacin, a Novel Drug Target in Female Infertility Tre…
2020
Abstract Despite huge progress in hormonal therapy and improved in vitro fertilization methods, the success rates in infertility treatment are still limited. A recently discovered mechanism revealed the interplay between the plasma protein fetuin‐B and the cortical granule‐based proteinase ovastacin to be a novel key mechanism in the regulation of fertilization. Upon sperm–egg fusion, cleavage of a distinct zona pellucida component by ovastacin destroys the sperm receptor, enhances zona robustness, and eventually provides a definitive block against polyspermy. An untimely onset of this zona hardening prior to fertilization would consequently result in infertility. Physiologically, this proc…
Molecular composition and chemotaxonomic aspects of Eocene amber from the Ameki Formation, Nigeria
2012
The molecular composition of fossil resin from the Eocene Ameki Formation, southern Nigeria has been analyzed by infrared spectroscopy, pyrolysis–gas chromatography–mass spectrometry and thermochemolysis gas chromatography–mass spectrometry to determine the structural class and botanical source of the resin. The pyrolysis products were dominated by bicyclic products derived from regular labdatriene structure and lacked succinic acid indicating Class Ib type amber. The biomarker compositions in the pyrolysates are dominated by sesquiterpenoids of the cadinane and bisabolane classes that are common constituents of higher plants and labdane type diterpenoids. The exclusive presence of labdane …
Análisis integrado de morfología y movilidad espermática humana con el uso del sperm class analyzer
2003
El uso de los sistemas computarizados de análisis seminal requiere su validación respecto de los métodos de uso generalizado de valoración referidos a los criterios de la OMS (1999). En este trabajo se pretende validar el uso del Sperm Class Analyzer® (V5.1) en el laboratorio clínico humano, así como abordar una análisis integrado de los diversos parámetros cinemáticos y morfométricos de los espermatozoides aportados por el sistema.En primer lugar, se trató de determinar las condiciones más adecuadas de adquisición de imágenes. Para ello, se utilizaron 9 muestras seminales con características heterogéneas. Un alícuota de cada una de las muestras se centrifugó con el fin de obtener plasma se…
Morphological characterization of ejaculated cynomolgus monkey (Macaca fascicularis) sperm
1999
The aim of this study was to give reference values for the frequency of morphological sperm abnormalities present in the semen from non-experimental cynomolgus monkeys as well as for the dimensions of sperm heads. Spermatozoa from the liquid portion of electroejaculates from 14 cynomolgus monkeys were air-dried as smears, fixed, and stained with Harris's Haematoxylin and subjected to visual analysis of morphology and computer-aided analysis of ten morphometric variables. The majority (83%) of sperm were morphologically normal. Tail defects were the most common (11%), and showed the highest variation between individuals, the values ranging between 4 and 23%. Head abnormalities consisted of l…
A Red Eye Colour Mutation in Culex pipiens after X-irradiation
1963
FOUR 1–2-day-old males of Culex pipiens were irradiated with a dose of 4,000 r. The mutant ‘red eye’ (r) was isolated from F3 cultures of two of the irradiated males (♂ II and ♂ IV). From male II, there were three red-eyed females which arose out of a single F2 brother–sister mating; from male IV, 80 red-eyed females and one red-eyed male from 14 F2 brother–sister matings. According to the experimental procedure, this means that at least one sperm from male II and at least fourteen sperms from male IV carried the mutation r. Thus, the same mutation was recovered in parallel from two irradiated males. The clustered appearance of the mutation in male IV was presumably caused by the occurrence…
Copulation and sperm induction by normal and palpless male linyphiid spiders.
1967
The performance by palpless male linyphiid spiders of behaviors associated with copulation and sperm induction indicates that occurrence of these sexual activities does not depend on peripheral input from the palps.
Testis asymmetry in birds: the influences of sexual and natural selection
2014
Gonad size and shape asymmetries are particularly common in birds. Although some obvious size and shape differences between the left and right testes in birds were first documented more than a century ago, little is known about what influences the variation across species in either the degree or the direction of these asymmetries. Here we show that a left bias in size is the most likely ancestral state in most orders and families, and that there is a weak but significant negative relation between the degree of size and shape asymmetries. In extant species, testis size and shape symmetries increase with the degree of sperm competition (relative testes mass), but those relations are significa…
Supplementary material 1 from: Pirie MD, Chatrou LW, Maas PJM (2018) A taxonomic revision of the Neotropical genus Cremastosperma (Annonaceae), inclu…
2018
A file incorporating the georeferenced part of this data that can be opened in Google Earth :
Supplementary material 2 from: Pirie MD, Chatrou LW, Maas PJM (2018) A taxonomic revision of the Neotropical genus Cremastosperma (Annonaceae), inclu…
2018
Full tables of Cremastosperma collections data (CSV, XLS and DBF formats) : Data type: occurences