Tag Archives: sperm

Does it pay to be a lover or a fighter? It depends on how you woo females

As mating season approaches, male animals are faced with a question that can make or break their chances at reproducing: does it pay to be a lover or a fighter? Or both?

Researchers from The University of Manchester and Syracuse University in New York working with the University of Western Australia, found that where animals fall on the lover/fighter scale depends on how much they are able to ensure continued mating rights with females.

In species where fighting for the right to mate means greater control of females, such as in the elephant seal, males invest more in weapons and less in testes size. (more…)

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UCLA researchers discover sperm move along a ‘twisting ribbon’

Opening the door to more sophisticated investigation of sperm locomotion and biophysics, researchers from UCLA’s Henry Samueli School of Engineering and Applied Science have identified previously unobserved swimming patterns in human and horse sperm cells.

This research, published in Scientific Reports, a journal of the Nature Publishing Group, could lead to a deeper understanding of how sperm move on their way to fertilization or other functions and how they react when encountering various toxins or chemicals. (more…)

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Selfish Gene may Undermine Genome Police

Biologists have been observing the “selfish” genetic entity segregation distorter (SD) in fruit flies for decades. Its story is a thriller among molecules, in which the SD gene destroys maturing sperm that have a rival chromosome. A new study reveals a tactic that gives SD’s villainy an extra edge.

PROVIDENCE, R.I. [Brown University] — For a bunch of inanimate chemical compounds, the nucleic and amino acids caught up in the infamous “selfish” segregation distorter (SD) saga have put on quite a soap opera for biologists since the phenomenon was discovered in fruit flies 50 years ago. A new study, a highlight in the March issue of the journal Genetics, provides the latest plot twist. (more…)

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Electrically Spun Fabric Offers Dual Defense Against Pregnancy, HIV

The only way to protect against HIV and unintended pregnancy today is the condom. It’s an effective technology, but not appropriate or popular in all situations.

A University of Washington team has developed a versatile platform to simultaneously offer contraception and prevent HIV. Electrically spun cloth with nanometer-sized fibers can dissolve to release drugs, providing a platform for cheap, discrete and reversible protection. (more…)

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Sperm Length Variation is not a Good Sign

A new study published online in the journal Human Reproduction finds that the greater the inconsistency in the length of sperm, particularly in the tail (flagellum), the lower the concentration of sperm that can swim well. The finding offers fertility clinicians a potential new marker for fertility trouble that might trace back to how a patient’s sperm are being made.

PROVIDENCE, R.I. [Brown University] — Perhaps variety is the very spice of life, but as a matter of producing human life, it could be the bane of existence. That’s the indication of a new study in the journal Human Reproduction that found men with wider variation in sperm length, particularly in the flagellum, had lower concentrations of sperm that could swim well. Those with more consistently made sperm seemed to have more capable ones.

“Our study reveals that men who produce higher concentrations of competent swimming sperm also demonstrate less variation in the size and shape of those sperm,” said Jim Mossman, a postdoctoral scholar at Brown University and lead author of the paper published in advance online Oct. 28. “It suggests that in some cases, testes are working more optimally to produce high numbers of consistently manufactured sperm, and vice versa.” (more…)

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New Fish Species Offers Literal Take on ‘Hooking Up’

Fishing hooks aren’t the only hooks found in east-central Mexican waters.

A new species of freshwater fish described by a North Carolina State University researcher has several interesting – and perhaps cringe-inducing – characteristics, including a series of four hooks on the male genitalia.

Females of the new species – the llanos mosquitofish, or Gambusia quadruncus – also have distinguishing characteristics, including a colorful anal spot. (more…)

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Nutrition Tied to Improved Sperm DNA Quality in Older Men

Berkeley Lab study links healthy micronutrient intake with reduced DNA fragmentation

A new study led by scientists from the U.S. Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab) found that a healthy intake of micronutrients is strongly associated with improved sperm DNA quality in older men. In younger men, however, a higher intake of micronutrients didn’t improve their sperm DNA.

In an analysis of 80 healthy male volunteers between 22 and 80 years of age, the scientists found that men older than 44 who consumed the most vitamin C had 20 percent less sperm DNA damage compared to men older than 44 who consumed the least vitamin C. The same was true for vitamin E, zinc, and folate. (more…)

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Pollination with Precision: How Flowers Do It

Pollination could be a chaotic disaster. With hundreds of pollen grains growing long tubes to ovules to deliver their sperm to female gametes, how can a flower ensure that exactly two fertile sperm reach every ovule? In a new study, Brown University biologists report the discovery of how plants optimize the distribution of pollen for successful reproduction.

PROVIDENCE, R.I. [Brown University] — Next Mother’s Day, say it with an evolved model of logistical efficiency — a flower. A new discovery about how nature’s icons of romance manage the distribution of sperm among female gametes with industrial precision helps explain why the delicate beauties have reproduced prolifically enough to dominate the earth.

In pollination, hundreds of sperm-carrying pollen grains stick to the stigma suspended in the middle of a flower and quickly grow a tube down a long shaft called a style toward clusters of ovules, which hold two female sex cells. This could be a chaotic frenzy, but for the plant to succeed, exactly two fertile sperm should reach the two cells in each ovule — no more, no less. No ovule should be left out, either because too many tubes have gone elsewhere, or because the delivered sperm don’t work. (more…)

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