New and Exciting in PLoS Medicine and PLoS Biology

There is new cool stuff published last night in PLoS Biology and PLoS Medicine, including:

Here is a write-up: Do Abstinence-Plus Interventions Reduce Sexual Risk Behavior among Youth?

And this is the actual paper: :

In an extensive search for existing abstinence-plus studies, the researchers identified 39 trials done in high-income countries that compared the effects on sexual behavior of various abstinence-plus programs with the effects of no intervention or of other interventions designed to prevent HIV infection. All the trials met strict preset criteria (for example, trial participants had to have an unknown or negative HIV status), and all studies meeting the criteria turned out to involve young people in the US, Canada, or the Bahamas, nearly 40,000 participants in total. In 23 of the trials, the abstinence-plus program studied was found to improve at least one self-reported protective sexual behavior (for example, it increased abstinence or condom use) when compared to the other interventions in the trial; none of the trials reported a significant negative effect on any behavioral outcome. Limited evidence from a few trials indicated that some abstinence-plus programs reduced pregnancy rates, providing a biological indicator of program effectiveness. Conversely, there were no indications of adverse biological outcomes such as an increased occurrence of sexually transmitted diseases in any of the trials.

Will Spam Overwhelm Our Defenses? Evaluating Offerings for Drugs and Natural Health Products:

* Spam, or unsolicited e-mail received from an unknown sender, now accounts for the largest proportion of all messages delivered online.
* Little is known about health-related spam and the spammers behind it.
* This study shows that it is possible to purchase products purported to be prescription drugs and controlled substances, across traditional national and legal boundaries, with one-third of our attempts to do so being successful.
* Buyers should be fully aware that it may not be possible for them to hold spammers accountable for any claims made in their messages, or to get protection from illegal activities resulting from disclosure of personal or financial information to spammers.
* Spammers are challenging our traditional regulatory, licensing, and law enforcement frameworks, and even threatening their relevance.

Interlocking Transcriptional Feedback Loops Control White-Opaque Switching in Candida albicans (Synopsis is here):

The opportunistic fungal pathogen Candida albicans can switch between two heritable states--the "white" and "opaque" states. These two cell types differ in many characteristics, including cell structure, mating competence, and virulence. Recent studies of the molecular mechanism of regulating the white-opaque switch identified a master transcriptional regulator, Wor1. In this study, we identified two transcriptional regulators, Czf1 and Wor2, as new regulators of white-opaque switching. By constructing a series of single and double mutants and by examining where the master regulator Wor1 binds throughout the genome, we generated a molecular model of the bistable switch that regulates white-opaque switching. The regulatory model consists of interlocking positive feedback loops, which mutually reinforce one another and stabilize the opaque state. These results show how an organism can exist in two distinctive, heritable states without changes in the nucleotide sequence of its genome.

Coloration and the Genetics of Adaptation:

How do organisms adapt to new environments? The popular conception of the adaptive process generally runs like this: A mutation arises that leads to an improved phenotype under novel environmental conditions (for example, a beak modification suited to exploiting an untapped food source). Because of the enhanced reproductive success of individuals carrying the mutant allele (or gene variant), the frequency of the mutant allele increases. The mutant allele eventually becomes fixed in the population--that is, every member of the population has two copies of the allele--and the population has increased its fitness. The whole process can then repeat itself when the environment changes again.

Bacterial Solutions to the Problem of Sex:

'Why sex?' is a question that has occupied the minds of evolutionary biologists for more than a century. The evolution of organisms that mix their genes during reproduction is considered one of the major transitions in evolution [1], because it fundamentally changed how genes are transmitted to the next generation. In asexual reproduction, offspring inherit a more or less unaltered genome from the parent. In sexual reproduction, genetic material is first reduced in the gametes (sperm or ovaries) and then fused with that of another individual, before new offspring may develop. Sexual reproduction has led to the evolution of males and females with different and sometimes even opposing reproductive interests and behavior. The consequence of sex, which many evolutionary biologists think explains its existence, is the production of genetic variation by mixing genes from different individuals.