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#1 Guest_AC-Editor_*

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Posted 10 February 2008 - 08:46 PM

Wrote these for the Winter American Currents. Had to cut them for space. Thought I'd share them here instead:

Will water rationing become a reality in southern California? On 14 Sept. 2007, the Los Angeles Times reported on a U.S. District Court decision requiring tougher protections for the Delta Smelt, Hypomesus transpacificus, a federally threatened species. Water from the fish’s habitat in the Sacramento-San Joaquin Delta is pumped via aqueduct to drier sections of the Golden State, but the three-inch fish, a poor swimmer, is sucked up and killed by the powerful pumps. State water authorities warn that the ruling could cut water exports from Delta by at least a third and possibly necessitate water rationing.

Speaking of dwindling water resources in the arid American west, a paper in the Sept. 2007 issue of BioScience warns that explosive population growth in Las Vegas could "burn regional biodiversity." The authors are most worried about plans to tap a groundwater aquifer that extends from Salt Lake City, Utah, to Death Valley, California. If water rights are granted, "declines in the water table, spring discharge, wetland area, and streamflow will adversely affect 20 federally listed species, 137 other water-dependent endemic species, and thousands of rural domestic and agricultural water users in the region." The authors recommend several cost-effective technologies, including the recovery of urban runoff and desalinization, as ways to meet competing human and ecological water needs.

The 2 Nov. 2007 issue of the New York Times reports that federal financing for the four-decade, $8 billion effort to rescue the Florida Everlglades—believed to be the world’s largest and most expensive environmental restoration—has slowed to a trickle. "Projects are already years behind schedule," the Times says. "Thousands of acres of wetlands and wildlife habitat continue to disappear, paved by developers or blasted by rock miners to feed the hungry construction industry."

And finally some good news—maybe. On 1 Sept. 2007, Scientific American reported that Japanese scientists are spawning endangered trout from the bodies of non-endangered salmon. The scientists injected trout spermatagoinia—the specialized sex cells that can grow into sperm or eggs—into sterlized salmon embryos. Since the embryos are sterilized, the new sex cells take over and mature into viable eggs and sperm. Offspring are normal-looking and able to reproduce on their own. As long as spermatagoinia from endangered fishes is collected and cryopreserved, researchers believe they can apply the technique to regenerate a fish should it go extinct.

#2 Guest_fishlvr_*

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Posted 10 February 2008 - 08:52 PM

Thanks for putting all of that on here!


And finally some good news—maybe. On 1 Sept. 2007, Scientific American reported that Japanese scientists are spawning endangered trout from the bodies of non-endangered salmon. The scientists injected trout spermatagoinia—the specialized sex cells that can grow into sperm or eggs—into sterlized salmon embryos. Since the embryos are sterilized, the new sex cells take over and mature into viable eggs and sperm. Offspring are normal-looking and able to reproduce on their own. As long as spermatagoinia from endangered fishes is collected and cryopreserved, researchers believe they can apply the technique to regenerate a fish should it go extinct.


That's pretty cool. I've never heard of that before. Can it be done with other rare fish? Like some of the highly endangered pupfish and such?

#3 Guest_fundulus_*

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Posted 10 February 2008 - 08:57 PM

Unfortunately I'm not surprised, it's that old human trick of too many of us living in places like Las Vegas where very few should live.

I've been intrigued by that report about inducing trout gametogenesis in salmon. Spermatagonia are actually immature sperm cells, but the art here is to induce them to differentiate into either eggs or sperm cells from what I've read. If this can happen inside the vehicle of a salmon zygote with a sterilized (dead?) embryo I guess the cellular apparatus is available to support growth. My only question, which maybe is addressed in the literature, is that it would appear that the original embryo's mitochondria and other organelles may be taken up by the new embryo. If this is true, the new embryo has some of the old's genome in the form of mitochondrial DNA. Hopefully I'm wrong.

#4 Guest_Newt_*

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Posted 11 February 2008 - 11:08 AM

Unfortunately I'm not surprised, it's that old human trick of too many of us living in places like Las Vegas where very few should live.

I've been intrigued by that report about inducing trout gametogenesis in salmon. Spermatagonia are actually immature sperm cells, but the art here is to induce them to differentiate into either eggs or sperm cells from what I've read. If this can happen inside the vehicle of a salmon zygote with a sterilized (dead?) embryo I guess the cellular apparatus is available to support growth. My only question, which maybe is addressed in the literature, is that it would appear that the original embryo's mitochondria and other organelles may be taken up by the new embryo. If this is true, the new embryo has some of the old's genome in the form of mitochondrial DNA. Hopefully I'm wrong.


Very interesting stuff.

*SPECULATION ALERT* Can't say I'm an expert on the matter, but I seem to recall that spermatogonia have a full complement of mitochondria. Presumably the surrogate embryo's mitochondria would be killed by the sterilization process (whatever it is). So the trout egg mitochondria would be the only mitochondria in the new zygote- it's like carrying on normal fertilization inside the cellular membrane of the dead salmon egg.

AC-Editor- Do you know if the trout and salmon are both Onchorhynchus species? Just curious.

I kind of doubt that the alternatives suggested to Las Vegas will be used unless a lot of outside pressure is applied. That town's government is not worried about the long term. Hopefully either the feds or the various other municipalities that would be hurt by Vegas' aquifer tap will prevent them from doing it, but who knows. That place is already a catastrophe.



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