What we know and what we need to know about the role of endogenous CCK in psychostimulant sensitization

The unique distribution of CCK and its receptors and its co-localization with dopamine makes it ideally situated to pay a role in dopamine-mediated reward and psychostimulant sensitization. A number of studies support the hypothesis that CCK acting through the CCK 1 and CCK 2 receptors is an endogenous modulator of dopamine neurotransmission. Behavioral studies with CCK antagonists and CCK 1 receptor mutant rats support a role for endogenous CCK in behavioral sensitization to psychostimulants. CCK microdialysis studies in the nucleus accumbens (NAC) have demonstrated that extracellular CCK is increased in the NAC by psychostimulants, providing neurochemical evidence that CCK could be involved in the behavioral response to psychostimulants. A model for how CCK may be acting in multiple brain regions to foster sensitization is presented and the gaps in our knowledge about the role of CCK in psychostimulant sensitization are described.     

Membrane fission by dynamin: what we know and what we need to know

The large GTPase dynamin is the first protein shown to catalyze membrane fission. Dynamin and its related proteins are essential to many cell functions, from endocytosis to organelle division and fusion, and it plays a critical role in many physiological functions such as synaptic transmission and muscle contraction. Research of the past three decades has focused on understanding how dynamin works. In this review, we present the basis for an emerging consensus on how dynamin functions. Three properties of dynamin are strongly supported by experimental data: first, dynamin oligomerizes into a helical polymer; second, dynamin oligomer constricts in the presence of GTP; and third, dynamin catalyzes membrane fission upon GTP hydrolysis. We present the two current models for fission, essentially diverging in how GTP energy is spent. We further discuss how future research might solve the remaining open questions presently under discussion.     

Gorilla society: What we know and don't know

Science is fairly certain that the gorilla lineage separated from the remainder of the hominoid clade about eight million years ago, 2 , 4 and that the chimpanzee lineage and hominin clade did so about a million years after that. 1 , 2 However, just this year, 2007, it was discovered that although the human head louse separated from the congeneric chimpanzee body louse (Pediculus) around the same time as the chimpanzee and hominin lineages split, 3 the human pubic louse apparently split from its sister species, the congeneric gorilla louse, Pthirus, 4.5 million years after their host lineages split. 3 No tested explanations exist for the discrepancy. Much is known about hominin evolution, but much remains to be discovered. The same is true of primate socioecology in general and gorilla socioecology in particular.     

What conservationists need to know about farming

Farming is the basis of our civilization yet is more damaging to wild nature than any other sector of human activity. Here, we propose that in order to limit its impact into the future, conservation researchers and practitioners need to address several big topics--about the scale of future demand, about which crops and livestock to study, about whether low-yield or high-yield farming has the potential to be least harmful to nature, about the environmental performance of new and existing farming methods, and about the measures needed to enable promising approaches and techniques to deliver on their potential. Tackling these issues requires conservationists to explore the many consequences that decisions about agriculture have beyond the farm, to think broadly and imaginatively about the scale and scope of what is required to halt biodiversity loss, and to be brave enough to test and when necessary support counterintuitive measures.     

Vomocytosis: What we know so far

Vomocytosis, or nonlytic exocytosis, has been reported for Cryptococcus neoformans since 2006. Since then, the repertoire of vomocytosing pathogens and host cells has increased and so have the molecular components linked to vomocytosis occurrence. Nonetheless, the mechanism underlying this phenomenon, whether it is triggered by the host or the pathogen, and how it affects disease progression are still unresolved. This review contains a summary of the main findings regarding vomocytosis and the outstanding questions puzzling scientists to this day.     

Amphibian decline and extinction: what we know and what we need to learn

For over 350 million yr, thousands of amphibian species have lived on Earth. Since the 1980s, amphibians have been disappearing at an alarming rate, in many cases quite suddenly. What is causing these declines and extinctions? In the modern era (post 1500) there are 6 leading causes of biodiversity loss in general, and all of these acting alone or together are responsible for modern amphibian declines: commercial use; introduced/exotic species that compete with, prey on, and parasitize native frogs and salamanders; land use change; contaminants; climate change; and infectious disease. The first 3 causes are historical in the sense that they have been operating for hundreds of years, although the rate of change due to each accelerated greatly after about the mid-20th century. Contaminants, climate change, and emerging infectious diseases are modern causes suspected of being responsible for the so-called 'enigmatic decline' of amphibians in protected areas. Introduced/exotic pathogens, land use change, and infectious disease are the 3 causes with a clear role in amphibian decline as well as extinction; thus far, the other 3 causes are only implicated in decline and not extinction. The present work is a review of the 6 causes with a focus on pathogens and suggested areas where new research is needed. Batrachochytrium dendrobatidis (Bd) is a chytrid fungus that is an emerging infectious disease causing amphibian population decline and species extinction. Historically, pathogens have not been seen as a major cause of extinction, but Bd is an exception, which is why it is such an interesting, important pathogen to understand. The late 20th and early 21st century global biodiversity loss is characterized as a sixth extinction event. Amphibians are a striking example of these losses as they disappear at a rate that greatly exceeds historical levels. Consequently, modern amphibian decline and extinction is a lens through which we can view the larger story of biodiversity loss and its consequences.     

Breast cancer genetics: what we know and what we need

Breast cancer results from genetic and environmental factors leading to the accumulation of mutations in essential genes. Genetic predisposition may have a strong, almost singular effect, as with BRCA1 and BRCA2, or may represent the cumulative effects of multiple low-penetrance susceptibility alleles. Here we review high- and low-penetrance breast-cancer-susceptibility alleles and discuss ongoing efforts to identify additional susceptibility genes. Ultimately these discoveries will lead to individualized breast cancer risk assessment and a reduction in breast cancer incidence.     

The detection of estrus in cattle raised under tropical conditions: what we know and what we need to know

Lack of accuracy in estrus detection in cattle is a major constraint affecting the implementation of techniques such as artificial insemination (AI) and embryo transfer (ET). For this reason clinicians have opted to pharmacologically manipulate the estrus cycle. The advantages and shortcomings of using this approach to improve the implementation of AI and ET are discussed in this review. Moreover, in order to highlight the reasons why estrus detection is difficult in cows kept at grazing in the tropics, this review underlines social and behavioral traits hindering the capacity of the casual observer to accurately identify cows in estrus.     

What we know and don't know about Earth's missing biodiversity

Estimates of non-microbial diversity on Earth range from 2 million to over 50 million species, with great uncertainties in numbers of insects, fungi, nematodes, and deep-sea organisms. We summarize estimates for major taxa, the methods used to obtain them, and prospects for further discoveries. Major challenges include frequent synonymy, the difficulty of discriminating certain species by morphology alone, and the fact that many undiscovered species are small, difficult to find, or have small geographic ranges. Cryptic species could be numerous in some taxa. Novel techniques, such as DNA barcoding, new databases, and crowd-sourcing, could greatly accelerate the rate of species discovery. Such advances are timely. Most missing species probably live in biodiversity hotspots, where habitat destruction is rife, and so current estimates of extinction rates from known species are too low.