Morphology and Fertility of Guinea Pig Spermatozoa Aged In Vivo

Shepherd, Benjamin A.; Martan, Jan

doi:10.3109/01485017908987292

Cited by 9 publications

(3 citation statements)

References 9 publications

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“…The term “rouleaux” has been used to describe the orderly stacks of sperm that form in the lumen of the cauda epididymides of guinea pigs and naked‐tail armadillos (Fawcett & Hollenberg, 1963; Heath, Meritt & Jeyendran, 1987; Shepherd & Martan, 1979). These conjugates are organized with the convex surface of one paddle‐shaped sperm head fitting into the concave surface of another, followed by adhesion of their plasma membranes (Fawcett, 1975; Fawcett & Hollenberg, 1963; Shepherd & Martan, 1979). We suggest that this term should be extended to other taxa for which sperm bear adaptations for orderly stacking, including some solifuges (Fig.…”

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confidence: 99%

Evolution of intra-ejaculate sperm interactions: do sperm cooperate?

2010

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Sperm are often considered to be individuals, in part because of their unique genetic identities produced as a result of synapsis during meiosis, and in part due to their unique ecology, being ejected away from the soma to continue their existence in a foreign environment. Selection at the level of individual sperm has been suggested to explain the evolution of two enigmatic sperm phenotypes: sperm heteromorphism, where more than one type of sperm is produced by a male, and sperm conjugation, where multiple sperm join together for motility and transport through the female reproductive tract before dissociation prior to fertilization. In sperm heteromorphic species, only one of the sperm morphs typically participates in fertilization, with the non-fertilizing "parasperm" being interpreted as reproductive altruists. Likewise, in species with sperm conjugation, high levels of sperm mortality have been suggested to be required for conjugate break-up and this has been considered evidence of kin-selected altruism. However, it is unclear if sperm possess the heritable variation in fitness (i.e. are individuals) required for the evolution of cooperation. We investigate the question of sperm individuality by focusing on how sperm morphology is determined and how sperm conjugates are formed. Concentrating on sperm conjugation, we discuss functional hypotheses for the evolutionary maintenance of this remarkable trait. Additionally, we speculate on the potential origins of sperm heteromorphism and conjugation, and explore the diversification and losses of these traits once they have arisen in a lineage. We find current evidence insufficient to support the concept of sperm control over their form or function. Thus, without additional evidence of haploid selection (i.e. sperm phenotypes that reflect their haploid genome and result in heritable differences in fitness), sperm heteromorphism and conjugation should be interpreted not as cooperation but rather as traits selected at the level of the male, much like other ejaculatory traits such as accessory gland proteins and ejaculate size.

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confidence: 99%

Evolution of intra-ejaculate sperm interactions: do sperm cooperate?

2010

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“…Males were used for sperm harvest, and females were artificially inseminated by surgical or nonsurgical methods. 26,29,30 The animals were fed ad libitum Prolab Guinea Pig 5P18 (LabDiet, St Louis, MO) that was stated to contain 1.5 IU/g vitamin D 3 , 0.89% Ca, 0.70% P, 0.41% nonphytate P, 0.3% Mg, and 1.28% potassium (K). In addition, guinea pigs received autoclaved hay 3 days a week and BioServ Veggie-Bites (BioServ, Frenchtown, NJ) 2 days a week.…”

Section: Animalsmentioning

confidence: 99%

“…20) and 7 females between 4 and 17 months of age (case Nos. [21][22][23][24][25][26][27]. Clinical signs exhibited by exposed and recovered animals while on the high vitamin D diet are also shown.…”

Section: Animalsmentioning

confidence: 99%

Hypervitaminosis D and Metastatic Calcification in a Colony of Inbred Strain 13 Guinea Pigs, Cavia porcellus

et al. 2014

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A commercial diet fed to a colony of inbred strain 13 guinea pigs for approximately 6 weeks was subsequently recalled for excessive levels of vitamin D. Twenty-one of 62 animals exhibited clinical signs, including anorexia, lethargy, and poor body condition. Nine affected and 4 clinically normal animals were euthanized for further evaluation, including serum chemistry, urinalysis, and gross and/or histopathology. Macroscopic findings included white discoloration in multiple organs in 8 animals, and microscopic evaluation confirmed multiorgan mineralization in tissues from 7 animals. Serum 25-hydroxyvitamin D levels were elevated in 10 animals. Serum inorganic phosphorus and alkaline phosphatase levels were increased in all exposed animals; however, total calcium and ionized calcium levels were not significantly higher in exposed animals than in control strain 13 guinea pigs from a different institution. The data support a diagnosis of hypervitaminosis D with metastatic calcification. Following the diet recall, the remaining guinea pigs increased their food intake and regained body condition. Diagnostic testing of 8 animals euthanized approximately 3 months after returning to a normal diet demonstrated that serum parathyroid hormone remained significantly lower, and ionized calcium and ionized magnesium were significantly higher, in recovered animals compared to controls and exposed animals. These results indicate that diagnostic tests other than serum calcium are necessary for a diagnosis of hypervitaminosis D in guinea pigs.

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Studies on zonation in the epididymis of the guinea pig. I. Ultrastructural and biochemical analysis of the zone rich in large lipid droplets (zone II)

Hoffer

Karnovsky

1981

Anat. Rec.

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In the epididymis of the guinea pig, zone II exhibits striking histological features that distinguish it readily from the other six regions of the epididymis. At the light microscope level, the pseudostratified epithelium of zone II is characterized by tall principal cells that are densely packed with large, intensely staining granules or droplets ranging up to 8 mu in diameter. At the electron microscope level, the principal cells exhibit numerous large lipid droplets and abundant agranular endoplasmic reticulum, which is frequently arranged in concentric whorls around one or more of the droplets. Quantitative biochemical studies comparing zone II with zones I and III show that zone II contains 2.5 - 3-fold more cholesterol and a significantly greater amount of cholesterol ester than the other two zones. These data indicate that the epididymal duct of the guinea pig includes a clearly defined region of epithelial cells possessing ultrastructural and biochemical characteristics consistent with steroidogenic activity. The potential significance of these observations to the epididymal physiology of the guinea pig and epididymal physiology in general is discussed.

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Morphology and Fertility of Guinea Pig Spermatozoa Aged In Vivo

Cited by 9 publications

References 9 publications

Evolution of intra-ejaculate sperm interactions: do sperm cooperate?

Evolution of intra-ejaculate sperm interactions: do sperm cooperate?

Hypervitaminosis D and Metastatic Calcification in a Colony of Inbred Strain 13 Guinea Pigs, Cavia porcellus

Studies on zonation in the epididymis of the guinea pig. I. Ultrastructural and biochemical analysis of the zone rich in large lipid droplets (zone II)

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