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Tag: "reproductive" at biology news

Ongoing collapse of coral reef shark populations

...e to the functioning of coral reef ecosystems. The reproductive biology of reef sharks makes them particularly vulnerable to fishing, but until now, there have been no studies of the response of these sharks to fishing pressure. The new work focused on Australia’s Great Barrier Reef, which is widely considere...

New clues to how sex evolves

...als are males with a single X chromosome (X0). The reproductive organs contain about half of the cells in an adult worm, and the process of meiosis can be observed at every stage, as chromosomes first come together during the pairing process, then later separate during meiotic division. One result of failed pa...

Cracking the egg

... changes may pinpoint the molecular mechanisms for reproductive isolation, a primary cause for the origin of new species, and an astonishing diversity of mammals inhabiting Earth." ...

Tearing down the fungal cell wall

... of the cell wall of fungal spores produced in the reproductive phase of A. brassicicola's life cycle. The AbNPS2 gene most likely directs the synthesis of a molecule that plays an essential role in maintaining the structure of the cell wall of the conidia. Associate Professor Christopher Lawrence of the Virgi...

Cloned mice created from fully differentiated cells, a milestone in cloning research

...removed from a somatic cell ?any cell other than a reproductive cell ?and transferring it into an unfertilized egg that has had its chromosomes removed. Because the resulting new embryo contains the entire genome of the donor somatic cell it is an identical copy. This cloned embryo is then implanted into a surrog...

Vitamin D deficiency widespread during pregnancy

...ch in the department of obstetrics, gynecology and reproductive sciences at the University of Pittsburgh School of Medicine. "But differences were smaller between seasons for African-American mothers and babies, whose vitamin D deficiency remained more constant." Since vitamin D is made by the body in reaction...

Coated nanoparticles solve sticky drug-delivery problem

...luding the lungs, eyes, digestive tract and female reproductive system. Because of these barriers, doctors often must prescribe pills or injections that send drugs through the entire body, an approach that can lead to unwanted side effects or doses that are too weak to provide effective treatment. __IMAGE_2 ...

Fish can determine their social rank by observation alone, study finds

...s in aggressive bouts is therefore crucial to male reproductive fitness, and the ability to infer the relative strength of rivals before engaging them in potentially costly fights should be highly adaptive." When A. burtoni males fight, it's easy to spot the winner. Mature males have a menacing black stripe, o...

Circumcision: A proven strategy to prevent HIV

...tive if it is integrated with other prevention and reproductive health services. "We have wonderful new drugs to at least maintain people for many years with the virus, but meanwhile more people are getting infected at a rate of approximately 5,000 persons per day," said Bailey. "We cannot treat our way out of...

Salamanders suffer delayed effects of common herbicide

...ir. Scientists then tracked their survival to near reproductive age. Results from the study, which lasted about 500 days, indicated that the two highest concentrations increased salamander mortality during exposure. However, this mortality benefited the survivors who experienced lower competition-related mor...

Study of planarians offers insight into germ cell development

... can regenerate all that is removed, including the reproductive organs. In a new study published this month in ...ession in planarians that had had their bodies and reproductive organs detached from their brains, the planarians regenerated new bodies, but with no reproductive c...

Prehistoric mystery organism verified as giant fungus

...as never able to find a smoking gun in the form of reproductive structures that would convince the world that it was indeed a fungus," Hotton said. Co-authoring the Geology paper with Boyce, Hotton and Hueber himself were Marilyn Fogel, George Cody and Robert Hazen of the Carnegie Institution of Washington, an...

Update on census of world's most endangered cat -- Female Amur leopard found dead

...ld and four rearing cubs. Now we’ve lost a mature, reproductive leopardess and her potential cubs in a senseless killing. This is the third leopard killed within this area over the last five years and underscores the desperate need for a unified protected area with national park status if the leopard is to surviv...

Twenty of world's 162 grouper species threatened with extinction

...more than 50 years old. Several species only reach reproductive maturity later in life, making them particularly v...ture. In addition, commercial fishing that targets reproductive gatherings of adults further hinders replenishment of unmanaged populations. The threatened group...

Long-lived deep-sea fishes imperiled by technology, overfishing

... constrained by the fishes' long lifespans and low reproductive success, a panel of experts said today at the annu...these species. Long-lived fish usually have low reproductive rates, either because of low breeding success or high mortality. In the case of deep-sea fishes, bot...

Researchers discover new details about HIV-1 entry and infection

...precise mechanisms by which HIV-1 enters the lower reproductive tract of human females. The researchers separated and removed the outer lining of vaginal cells, which serves as the first barrier to the virus. The isolated preparation of intact, viable, vaginal epithelium permitted examination of immune cells that...

Procedure predicts embryos most likely to result in pregnancy

...sity have developed a procedure that estimates the reproductive potential of individual embryos, possibly leading ...ization is the inability to precisely estimate the reproductive potential of individual embryos," Seli said. "The successes of in-vitro fertilization often result f...

Phthalates now linked to fat, related health risks

...m plastics to soaps, already has been connected to reproductive problems and now, for the first time, is linked to...oor semen quality in men and subtle changes in the reproductive organs in boy babies. This connection between phthalates and testosterone helped to establish a basi...

Manipulating nature: Scientists query wildlife birth-control method

...t against some essential event or structure in the reproductive process. The antibodies can act against sperm, eggs or reproductive hormones, which prevent either fertilization or the production of sperm and ova. Proponents of t...

Early-stage sperm cells created from human bone marrow

... the laboratory and coaxed them into becoming male reproductive cells, which are scientifically known as ‘germ cells? Genetic markers showed the presence of partly-developed sperm cells called spermatagonial stem cells, which are an early phase of the male germ cell development. In most men, spermatagonial ce...

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