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I blog about research articles in sex and reproduction. Topics range from molecular interactions during sex to sexual behaviors of different animals (or plants!).
Evolution makes penises take on crazy shapes. But can male genital shape actually drive the evolution of two separate species? Researchers in Australia looked at populations of a millipede species with divergent genital shape to address this question. ... Read more »
Wojcieszek JM, & Simmons LW. (2013) Divergence in genital morphology may contribute to mechanical reproductive isolation in a millipede. Ecology and evolution, 3(2), 334-43. PMID: 23467632
Most people probably think of tastebuds as existing only on their tongues, but did you know there are taste buds in testes? It’s true. Sort of. They aren’t exactly like the taste buds in your mouth. Male germ cells–the cells that are destined to become sperm–have molecules on them that can detect bitter tastes.
... Read more »
Xu J, Cao J, Iguchi N, Riethmacher D, & Huang L. (2013) Functional characterization of bitter-taste receptors expressed in mammalian testis. Molecular human reproduction, 19(1), 17-28. PMID: 22983952
All kinds of things go into a woman’s vagina. Some are friendly (like sperm and vaginal microbes), and some are very bad (STDs). The immune system in the vagina has to be able to tell the difference and react appropriately. As you can imagine, the system isn’t perfect and sometimes things go terribly wrong.
An article published earlier this month in the journal Fronteirs in Immunology (available online for free) reviewed the current state of knowledge of the vaginal immune system......... Read more »
Clark GF, & Schust DJ. (2013) Manifestations of immune tolerance in the human female reproductive tract. Frontiers in immunology, 26. PMID: 23407606
The study, published this month in PLoS One, was conducted by Adrienn Uzsák and Coby Schal at North Carolina University…and some lovely German cockroaches. They found that when female cockroaches socialize, they produce eggs faster. And they don’t even have to socialize with other roaches! It just has to be an insect of roughly the same size and shape.... Read more »
Uzsák A, & Schal C. (2013) Sensory Cues Involved in Social Facilitation of Reproduction in Blattella germanica Females. PloS one, 8(2). PMID: 23405195
Kate Middleton might love being pregnant, but for the average woman it can be confusing and scary. Every day we learn about some new thing that, if you do it when you’re pregnant, can totally screw up your kid. By this point, pretty much everyone knows that you shouldn’t smoke or drink during pregnancy. Even sushi can be dangerous. But then you get a lot of contradictory information: drinking a little bit is OK…or is it?
So, in case you’re pregnant or thinking about b........ Read more »
Surén P, Roth C, Bresnahan M, Haugen M, Hornig M, Hirtz D, Lie KK, Lipkin WI, Magnus P, Reichborn-Kjennerud T.... (2013) Association between maternal use of folic acid supplements and risk of autism spectrum disorders in children. JAMA : the journal of the American Medical Association, 309(6), 570-7. PMID: 23403681
Symonds ME, Mendez MA, Meltzer HM, Koletzko B, Godfrey K, Forsyth S, & van der Beek EM. (2013) Early Life Nutritional Programming of Obesity: Mother-Child Cohort Studies. Annals of nutrition , 62(2), 137-145. PMID: 23392264
Bringhenti I, Moraes-Teixeira JA, Cunha MR, Ornellas F, Mandarim-de-Lacerda CA, & Aguila MB. (2013) Maternal Obesity during the Preconception and Early Life Periods Alters Pancreatic Development in Early and Adult Life in Male Mouse Offspring. PloS one, 8(1). PMID: 23383269
Pike KC, Inskip HM, Robinson SM, Cooper C, Godfrey KM, Roberts G, Lucas JS, & the Southampton Women's Survey Study Group. (2013) The relationship between maternal adiposity and infant weight gain, and childhood wheeze and atopy. Thorax. PMID: 23291350
Goats could potentially transmit a dangerous parasite, Toxoplasma gondii, in their semen, according to research by Flaviana Wanderley and colleagues in Brazil. Well...who cares? Why should scientists devote research dollars and time to purposely giving goats STDs, just to see if they can?
Like with so many other apparently bizarre research projects, the answer is: it's the economy, stupid!
Goat farming is very important in many countries, including Brazil and India. Goats are reared f........ Read more »
Wanderley F, Porto WJ, Câmara D, Cruz NL, Feitosa BC, Freire R, Moraes E, & Mota R. (2013) EXPERIMENTAL VAGINAL INFECTION OF GOATS WITH SEMEN CONTAMINATED WITH THE "CPG" STRAIN OF Toxoplasma gondii. The Journal of parasitology. PMID: 23391103
Octopus sperm is sneaky. It starts off all innocent and normal looking, while it’s sitting there in the testes waiting to go to bat. Then, once in the female, the acrosome reaction begins and the sperm shows its true, screwy self.
And I do mean screwy. Seriously. It looks like a screw.... Read more »
Li Z, Zhu JQ, & Yang WX. (2010) Acrosome reaction in Octopus tankahkeei induced by calcium ionophore A23187 and a possible role of the acrosomal screw. Micron (Oxford, England : 1993), 41(1), 39-46. PMID: 19729317
Tasmanian devils are rapidly face-cancering themselves to extinction. If we don’t do something soon, those weird little down-under devils will be gone forever. Enter: electroejaculation. Yes, it is exactly what it sounds like. An electric probe is inserted into the rectum of an anesthetized male animal (or human; this is also used for some infertility treatments). The probe stimulates the prostate and induces the animal to, um, provide a sample. A paper published this August in the journal........ Read more »
Keeley T, Harris M, McGreevy PD, Hudson D, & O'Brien JK. (2012) Development and evaluation of electroejaculation techniques in the Tasmanian devil (Sarcophilus harrisii). Reproduction, fertility, and development, 24(7), 1008-18. PMID: 22935162
Keeley T, McGreevy PD, & O'Brien JK. (2012) The effects of season and devil facial tumour disease on the reproductive physiology of the male Tasmanian devil (Sarcophilus harrisii). Reproduction, fertility, and development, 24(7), 999-1007. PMID: 22935161
Are you grossed out by blue cheese? (I’m not, but I know many who are). Does that blue-green marbling of delicious fungus kind of make you gag? Well, this little factoid probably won’t help: there may be sex going on in that cheese.
Until pretty recently, a big chunk of fungal species were thought to reproduce without sex–until people really started to look. It turns out, there’s a lot more sex going on in the fungal world (on the down-low) than people thought. And tha........ Read more »
Ropars J, Dupont J, Fontanillas E, Rodríguez de la Vega RC, Malagnac F, Coton M, Giraud T, & López-Villavicencio M. (2012) Sex in Cheese: Evidence for Sexuality in the Fungus Penicillium roqueforti. PloS one, 7(11). PMID: 23185400
Alexei Maklakov and colleagues in Sweden recently performed an experiment to see what effect sexual harassment (ie: constant, unwanted efforts by males to gain sex) had on the mutation rate of fruit flies in the next generation. The results were published online last week in the Proceedings of the Royal Society (see citation below).... Read more »
Maklakov AA, Immler S, Løvlie H, Flis I, & Friberg U. (2013) The effect of sexual harassment on lethal mutation rate in female Drosophila melanogaster. Proceedings. Biological sciences / The Royal Society, 280(1750), 20121874. PMID: 23173200
Since I missed last week’s sperm post, I thought I’d make up for it by writing about everyone’s favorite kind of sperm: giant. Who makes giant sperm? It’s not who you might think. The giants of the animal kingdom–whales, elephants–make sperm that are very similar to that of men and mice. Tiny. It’s the little guys who make the biggest sperm. In fact, as I’ve pointed out before, the largest sperm of all (and no, this is not relative to body size) ar........ Read more »
Yamada S, & Matzke-Karasz R. (2012) How is a giant sperm ejaculated? Anatomy and function of the sperm pump, or "Zenker organ," in Pseudocandona marchica (Crustacea, Ostracoda, Candonidae). Die Naturwissenschaften, 99(7), 523-35. PMID: 22684272
Joly D, Bressac C, Jaillard D, Lachaise D, & Lemullois M. (2003) The sperm roller: a modified testicular duct linked to giant sperm transport within the male reproductive tract. Journal of structural biology, 142(3), 348-55. PMID: 12781661
You may have seen this paper about scientists turning stem cells into fertile eggs hyped in media today (for example, this article at NPR). And of course, it deserves the hype. This is certainly a big breakthrough in stem cell research–especially induced pluripotent stem (iPS) cell research. iPS cells are similar to embryonic stem cells, except that they can be made out of any cell in the body.... Read more »
Katsuhiko Hayashi, Sugako Ogushi, Kazuki Kurimoto, So Shimamoto, Hiroshi Ohta, & Mitinori Saitou. (2012) Offspring from Oocytes Derived from in Vitro Primordial Germ Cell–Like Cells in Mice. Science. DOI: 10.1126/science.1226889
Hayashi K, Ohta H, Kurimoto K, Aramaki S, & Saitou M. (2011) Reconstitution of the mouse germ cell specification pathway in culture by pluripotent stem cells. Cell, 146(4), 519-32. PMID: 21820164
Sperm are pretty cool. Some are tiny, some are huge. Some have hooks, some crawl, and some can’t actually fertilize an egg. But all of them are awesome products of evolution. That’s why I want to start a collection of posts (let’s say weekly, and see how that goes) dedicated to quirky sperm. For the first post, a relatively recent paper (about a year old) on naked mole rat sperm.
... Read more »
van der Horst G, Maree L, Kotzé SH, & O'Riain MJ. (2011) Sperm structure and motility in the eusocial naked mole-rat, Heterocephalus glaber: a case of degenerative orthogenesis in the absence of sperm competition?. BMC evolutionary biology, 351. PMID: 22142177
Despite referring to sperm as “sperms”, this paper showing 3D tracking of human sperm swimming paths is pretty cool. Actually, I take that back. Calling them sperms definitely adds to the awesomeness. I won’t pretend to fully understand the physics behind their method, but it’s obvious that this imaging method will be important for many other things besides looking at sperm (which is already hugely important IMHO).... Read more »
Su TW, Xue L, & Ozcan A. (2012) High-throughput lensfree 3D tracking of human sperms reveals rare statistics of helical trajectories. Proceedings of the National Academy of Sciences of the United States of America. PMID: 22988076
Good news, guys: one day soon you may not have to worry about whether your girlfriend remembered to take her pill. The bad news? You might actually have to be the one who remembers to take it. A group of researchers at Baylor College of Medicine in Houston, the Dana-Farber Cancer Institute in Boston, and others have found a drug that may one day be used as a contraceptive in men. The drug, JQ1, blocks the tight packaging of DNA during sperm formation, which is critical for sperm to work normally........ Read more »
Matzuk MM, McKeown MR, Filippakopoulos P, Li Q, Ma L, Agno JE, Lemieux ME, Picaud S, Yu RN, Qi J.... (2012) Small-Molecule Inhibition of BRDT for Male Contraception. Cell, 150(4), 673-684. PMID: 22901802
The sperm of mice and men are streamlined cells, designed to move fast and deliver a payload. To maintain their Phelps-like speed through the long haul to the egg, sperm cells need energy. But even though sperm have all the equipment they need to turn fuel into energy, they don’t carry any fuel with them. Instead, they get their energy from the environment (read: lady parts).
Though many different fuels–glucose, lactic acid, and pyruvate–are present in the female genital tra........ Read more »
Mannowetz N, Wandernoth PM, & Wennemuth G. (2012) Glucose is a pH-Dependent Motor for Sperm Beat Frequency during Early Activation. PloS one, 7(7). PMID: 22911736
Scientists in Australia have been hard at work watching fruit flies have sex. Why? To figure out how fly sex affects your food. It is a fact of life that the facts of life can cause problems, especially when fruit flies lay eggs (after doing their business) in the fruits and veggies we grow for food.
Now, just to clarify, these “fruit flies” are not the adorable, lovable Drosophila melanogaster that haunt your wine glass and your genetics exams (yes, I may be biased in favor of Dr........ Read more »
Collins SR, Pérez-Staples D, & Taylor PW. (2012) A role for copula duration in fertility of Queensland fruit fly females mated by irradiated and unirradiated males. Journal of insect physiology. PMID: 22906778
Way back, before mosses and their brethren evolved, all sex happened in the water. This made things pretty easy for plants and other species that don't have fancy internal fertilization like us. All they had to do was let their sperm go forth, into the ocean, and eventually they would swim to a suitable female plant and, voilà! Sex.
But mosses, liverworts, and hornworts (a group of plants called bryophytes) brought sex to the land--but how did they adapt to the lack of water ........ Read more »
Rosenstiel TN, Shortlidge EE, Melnychenko AN, Pankow JF, & Eppley SM. (2012) Sex-specific volatile compounds influence microarthropod-mediated fertilization of moss. Nature. PMID: 22810584
Now that we know the Supreme Court’s decision on the healthcare law, we can get back to thinking about the big questions in life. For example: how does having an infection affect the health and vitality of your sperm?
At least in fruit flies, if either the male or female is sick, sperm can suffer, according to research from Preethi Radhakrishnan and Kenneth Fedorka at the University of Central Florida. And if a female gets sperm from an infected male, she’s likely to just dump the........ Read more »
Radhakrishnan P, & Fedorka KM. (2012) Immune activation decreases sperm viability in both sexes and influences female sperm storage. Proceedings. Biological sciences / The Royal Society. PMID: 22696524
Short SM, Wolfner MF, & Lazzaro BP. (2012) Female Drosophila melanogaster suffer reduced defense against infection due to seminal fluid components. Journal of insect physiology. PMID: 22698822
Rowe M, Czirják GÁ, McGraw KJ, & Giraudeau M. (2011) Sexual ornamentation reflects antibacterial activity of ejaculates in mallards. Biology letters, 7(5), 740-2. PMID: 21490006
This paper does two things: first, it lets me write a blog post in which I use the word ‘bitch’ 20 times (including that time). Second, and arguably more importantly, the results of this paper confirm what many other studies have shown over the years, in many different animals (including people): all that extra “stuff” in the semen is really important for optimal sperm performance.... Read more »
England GC, Russo M, & Freeman SL. (2012) The bitch uterine response to semen deposition and its modification by male accessory gland secretions. Veterinary journal (London, England : 1997). PMID: 22652115
Sharkey DJ, Tremellen KP, Jasper MJ, Gemzell-Danielsson K, & Robertson SA. (2012) Seminal fluid induces leukocyte recruitment and cytokine and chemokine mRNA expression in the human cervix after coitus. Journal of immunology (Baltimore, Md. : 1950), 188(5), 2445-54. PMID: 22271649
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