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PLoS Biology: Neural Activity Reveals Continuity Between Infant and Adult Sleep; Virus-host Interactions at Sea Effect Global Photosynthesis

April 12, 2005

Infant Sleep: A Precursor to Adult Sleep?

Sleep is absolutely essential for well-being. Just ask one of the 40 million Americans with sleep disorders who suffer crippling fatigue, impaired judgment, irritability, moodiness, and myriad health problems. Still, its precise function remains unclear. An intriguing role for REM sleep - the stage most closely associated with dreaming - was suggested almost 40 years ago when sleep researchers Howard Roffwarg and William Dement discovered that babies spend far more time in REM sleep than adults - prompting their hypothesis that infant REM sleep plays a role in central nervous system development. A central element of their hypothesis is built on whether the neural mechanisms of infant sleep differ significantly from those of adult sleep, but they relied on untested assumptions on the nature of infant sleep.

In a new study published in the open-access online journal PLoS Biology, Karl Karlsson, Mark Blumberg, and their colleagues tackle the technical difficulties involved in studying the tiny neonatal brain to investigate the neural activity associated with infant sleep states. Using techniques ranging from neural recording, anatomical tracing, and microlesioning, they provide evidence that the active sleep of week-old rats bears a striking resemblance to the conventional definitions of adult sleep. What's more, the neural mechanisms underlying the infant sleep state contain the primary components of adult sleep.

Altogether, the authors argue, these results show that sleep development elaborates on elementary components already in place soon after birth. If the neural mechanisms of infant and adult sleep were entirely different, then sleep might serve different purposes in infancy and adulthood. But the striking parallels outlined in this study suggest a developmental continuity between the two states. They also chart a course for future study that might even test Roffwarg's view that the neonatal brainstem primes the central nervous system for the sensory challenges that lie ahead - and could even be the stuff that dreams are made of.


Citation: Karlsson KÃ" , Gall AJ, Mohns EJ, Seelke AMH, Blumberg MS (2005) The neural substrates of infant sleep in rats. PLoS Biol 3(5): e143.


The published article will be accessible to your readers at:
http://www.plosbiology.org/plosonline/?request=get-document&doi=10.1371/journal.pbio.0030143

Press-only preview of the article: http://www.plos.org/press/plbi-03-05-blumberg.pdf

Related image for press use: http://www.plos.org/press/plbi-03-05-blumberg.jpg
"¢Caption: Though naked, helpless, and blind, this week-old rat (pictured with a quarter) already has the fundamental neural components of adult sleep. (Photo: Mark Blumberg)

CONTACT:
Mark Blumberg
University of Iowa
E11 Seashore Hall
Iowa City, IA USA 52242
+1-319-335-2424
+1-319-335-0191 (fax)
mark-blumberg@uiowa.edu

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Virus-host Interactions at Sea: The Third Age of Phage

Cyanobacteria exert a disproportionate influence on their planet for their size. The Prochlorococcus group of cyanobacteria account for a large fraction of global photosynthesis by virtue of their ubiquitous presence in nutrient-depleted ocean waters. Even tinier agents - the viruses that infect these bacteria, called cyanophages - appear capable of wielding surprising influence on global cycles by affecting the population dynamics and evolutionary path of Prochlorococcus. An investigation of the genetic makeup of three cyanophages in the freely-available online journal PLoS Biology helps reveal the complex role these phages might have on our great planetary cycles.

To understand the nature of virus-host interactions at sea, Sallie Chisholm and colleagues sequenced three marine phages - one podovirus and two myoviruses - based on their morphology and host range, and characterized their genomes. The marine phages resemble two terrestrial phages - called T4 and T7 - that infect Escherichia coli but also carry genes that appear specially adapted to infecting photosynthetic bacteria in nutrient-poor oceans. Some genes are likely derived from cyanobacteria that "could play defining functional roles" in marine phage-host interactions. All three cyanophages contain photosynthesis-related genes, some of which could mean that the virus helps the host maintain photosynthesis during infection. The podovirus also has a candidate gene involved in DNA synthesis, which the authors speculate could allow the virus to reproduce in nutrient-poor environments, and all three cyanophages carry genes involved in metabolizing carbon. The absence of such genes in terrestrial phages, the authors argue, lends support to the notion that marine phages have evolved different adaptive mechanisms in response to the ocean environment.

Given the intimate relation between virus and host, the effects of gene swapping between virus and host is likely to be a two-way street. Just as cyanophages may help shape the fate of their hosts, it's likely that cyanobacterial genes influence phage ecology and perhaps even its range. The cyanophages characterized here take after two phages that were central to many fundamental breakthroughs in molecular biology, including the discovery that genes are made of DNA. It remains to be seen how the marine versions of these legendary laboratory viruses contribute to our understanding of phage infections in one of the most abundant, ecologically diverse primary producers in the open seas. See also the related Primer "The Third Age of Phage" in the May issue of PLoS Biology (DOI: 10.1371/journal.pbio.0030182).


Citation: Sullivan MB, Coleman ML, Weigele P, Rohwer F, Chisholm SW (2005) Three Prochlorococcus cyanophage genomes: Signature features and ecological interpretations. PLoS Biol 3(5): e144.


The published article will be accessible to your readers at:
http://www.plosbiology.org/plosonline/?request=get-document&doi=10.1371/journal.pbio.0030158

Press-only preview of the article: http://www.plos.org/press/plbi-03-05-chisholm.pdf

Related image for press use: http://www.plos.org/press/plbi-03-05-chisholm.jpg
"¢Caption: Despite a striking resemblance to an E. coli virus, this marine virus appears to have evolved genes adapted to infecting photosynthetic bacteria inhabiting low nutrient oceans. (Scale bar indicates 100 nm) (Image: Peter Weigele)


CONTACT:
Sallie Chisholm
Massachusetts Institute of Technology
400 Main Street
MIT 48-425
Cambridge, MA USA 02139
+1-617-253-1771
chisholm@mit.edu



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THE FOLLOWING RESEARCH ARTICLES WILL ALSO BE PUBLISHED ONLINE:

A Combinatorial Code for Splicing Silencing: UAGG and GGGG Motifs

Many genes are alternatively spliced, but the signals that regulate the process are unclear. A sequence motif that appears to function at many alternatively spliced genes has been discovered.

Citation: Han K, Yeo G, An P, Burge CB, Grabowski PJ (2005) A combinatorial code for splicing silencing: UAGG and GGGG motifs. PLoS Biol 3(5): e158.


The published article will be accessible to your readers at:
http://www.plosbiology.org/plosonline/?request=get-document&doi=10.1371/journal.pbio.0030158

Press-only preview of the article: http://www.plos.org/press/plbi-03-05-grabowski.pdf


CONTACT:
Paula Grabowski
University of Pittsburgh
4249 Fifth Avenue
Pittsburgh, PA USA 15260
+1-412-624-6983
+1-412-624-4826 (fax)
pag4+@pitt.edu


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A New Yeast Poly(A) Polymerase Complex Involved in RNA Quality Control

A new molecular surveillance mechanism is uncovered in eukaryotes, in which incorrectly folded tRNAs are polyadenylated and then targeted for degradation.


Citation: Vanacova S, Wolf J, Martin G, Blank D, Dettwiler S, et al. (2005) A new yeast poly(A) polymerase complex involved in RNA quality control. PLoS Biol 3(6): e189.


The published article will be accessible to your readers at:
http://www.plosbiology.org/plosonline/?request=get-document&doi=10.1371/journal.pbio.0030189

Press-only preview of the article: http://www.plos.org/press/plbi-03-06-keller.pdf


CONTACT:
Walter Keller
Biozentrum, University of Basel
Klingelbergstrasse 50/70
Basel, CH-4056
Switzerland
+41-61-267-20-60
+41-61-267-20-79 (fax)
walter.keller@unibas.ch


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