Non-seasonal plant foods in the palawa (Tasmanian Aborigine) diet: 1: the Yam Daisy Microseris lanceolata (Walp.) Sch.Bip

The tuberous roots of the Yam Daisy/murnong Microseris lanceolata were a staple plant food for Indigenous peoples in Victoria and New South Wales. In contrast, although the Yam Daisy occurs in Tasmania, it is not recorded as being eaten by the Tasmanian Aborigines (palawa) although fossil Liguliflorae pollen indicate that this perennial herb was growing here before European occupation in 1805. Unlike in Victoria up to the 1840s, as yet, there is no fossil evidence to show the species was sufficiently common to make a significant non-seasonal contribution to the palawan diet. However, assuming an adequate supply of the tubers, the palawa could have obtained energy from the modest content of simple sugars (via glycolysis) and its substantial content of fructans (prebiotics, converted to absorbable fatty acids by gut bacteria). Its sweet taste at certain seasons may have encouraged seasonal consumption. Recent research suggests that fructans may have health benefits, e.g., improved immune function; however, it seems improbable that the palawa specifically recognised those benefit

Refractory periods and climate forcing in cholera dynamics

Outbreaks of many infectious diseases, including cholera, malaria and dengue, vary over characteristic periods longer than 1 year(1,2). Evidence that climate variability drives these interannual cycles has been highly controversial, chiefly because it is difficult to isolate the contribution of environmental forcing while taking into account nonlinear epidemiological dynamics generated by mechanisms such as host immunity(2-4). Here we show that a critical interplay of environmental forcing, specifically climate variability, and temporary immunity explains the interannual disease cycles present in a four-decade cholera time series from Matlab, Bangladesh. We reconstruct the transmission rate, the key epidemiological parameter affected by extrinsic forcing, over time for the predominant strain ( El Tor) with a nonlinear population model that permits a contributing effect of intrinsic immunity. Transmission shows clear interannual variability with a strong correspondence to climate patterns at long periods ( over 7 years, for monsoon rains and Brahmaputra river discharge) and at shorter periods ( under 7 years, for flood extent in Bangladesh, sea surface temperatures in the Bay of Bengal and the El Nino Southern Oscillation). The importance of the interplay between extrinsic and intrinsic factors in determining disease dynamics is illustrated during refractory periods, when population susceptibility levels are low as the result of immunity and the size of cholera outbreaks only weakly reflects climate forcing.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/62876/1/nature03820.pd

Extreme rainfall events alter the trophic structure in bromeliad tanks across the Neotropics

Changes in global and regional precipitation regimes are among the most pervasive components of climate change. Intensification of rainfall cycles, ranging from frequent downpours to severe droughts, could cause widespread, but largely unknown, alterations to trophic structure and ecosystem function. We conducted multi-site coordinated experiments to show how variation in the quantity and evenness of rainfall modulates trophic structure in 210 natural freshwater microcosms (tank bromeliads) across Central and South America (18°N to 29°S). The biomass of smaller organisms (detritivores) was higher under more stable hydrological conditions. Conversely, the biomass of predators was highest when rainfall was uneven, resulting in top-heavy biomass pyramids. These results illustrate how extremes of precipitation, resulting in localized droughts or flooding, can erode the base of freshwater food webs, with negative implications for the stability of trophic dynamics

Decreased SGK1 Expression and Function Contributes to Behavioral Deficits Induced by Traumatic Stress

Exposure to extreme stress can trigger the development of major depressive disorder (MDD) as well as post-traumatic stress disorder (PTSD). The molecular mechanisms underlying the structural and functional alterations within corticolimbic brain regions, including the prefrontal cortex (PFC) and amygdala of individuals subjected to traumatic stress, remain unknown. In this study, we show that serum and glucocorticoid regulated kinase 1 (SGK1) expression is down-regulated in the postmortem PFC of PTSD subjects. Furthermore, we demonstrate that inhibition of SGK1 in the rat medial PFC results in helplessness- and anhedonic-like behaviors in rodent models. These behavioral changes are accompanied by abnormal dendritic spine morphology and synaptic dysfunction. Together, the results are consistent with the possibility that altered SGK1 signaling contributes to the behavioral and morphological phenotypes associated with traumatic stress pathophysiology

Modeling Inhomogeneous DNA Replication Kinetics

In eukaryotic organisms, DNA replication is initiated at a series of chromosomal locations called origins, where replication forks are assembled proceeding bidirectionally to replicate the genome. The distribution and firing rate of these origins, in conjunction with the velocity at which forks progress, dictate the program of the replication process. Previous attempts at modeling DNA replication in eukaryotes have focused on cases where the firing rate and the velocity of replication forks are homogeneous, or uniform, across the genome. However, it is now known that there are large variations in origin activity along the genome and variations in fork velocities can also take place. Here, we generalize previous approaches to modeling replication, to allow for arbitrary spatial variation of initiation rates and fork velocities. We derive rate equations for left- and right-moving forks and for replication probability over time that can be solved numerically to obtain the mean-field replication program. This method accurately reproduces the results of DNA replication simulation. We also successfully adapted our approach to the inverse problem of fitting measurements of DNA replication performed on single DNA molecules. Since such measurements are performed on specified portion of the genome, the examined DNA molecules may be replicated by forks that originate either within the studied molecule or outside of it. This problem was solved by using an effective flux of incoming replication forks at the model boundaries to represent the origin activity outside the studied region. Using this approach, we show that reliable inferences can be made about the replication of specific portions of the genome even if the amount of data that can be obtained from single-molecule experiments is generally limited

Effects of the neurogranin variant rs12807809 on thalamocortical morphology in schizophrenia

10.1371/journal.pone.0085603PLoS ONE812-POLN

Sleep disturbances in an arctic population: The Tromsø Study

<p>Abstract</p> <p>Background</p> <p>Prevalence estimates for insomnia range from 10 to 50% in the adult general population. Sleep disturbances cause great impairment in quality of life, which might even rival or exceed the impairment in other chronic medical disorders. The economic implications and use of health-care services related to chronic insomnia represent a clinical concern as well as a pronounced public health problem. Hypnotics are frequently prescribed for insomnia, but alcohol and over-the-counter sleep aids seem to be more widely used by insomniacs than prescription medications. Despite the complex relationship between insomnia and physical and mental health factors, the condition appears to be underrecognized and undertreated by health care providers, probably due to the generally limited knowledge of the causes and natural development of insomnia.</p> <p>Methods/Design</p> <p>The Tromsø Study is an ongoing population-based cohort study with five previous health studies undertaken between 1974 and 2001. This protocol outlines a planned study within the sixth Tromsø Study (Tromsø VI), aiming at; 1) describing sleep patterns in a community-based sample representative of the general population of northern Norway, and 2) examining outcome variables of sleep disturbances against possible explanatory and confounding variables, both within a cross-sectional approach, as well as retrospectively in a longitudinal study – exploring sleep patterns in subjects who have attended two or more of the previous Tromsø studies between 1974 and 2009. First, we plan to perform a simple screening in order to identify those participants with probable sleep disturbances, and secondly to investigate these sleep disturbances further, using an extensive sleep-questionnaire. We will also collect biological explanatory variables, i.e. blood samples, weight, height and blood pressure. We plan to merge data on an individual level from the Tromsø VI Study with data from the Norwegian Prescription Database (NorPD), which is a national registry including data for all prescription drugs issued at Norwegian pharmacies. Participants with sleep disturbances will be compared with pair-matched controls without sleep disturbances.</p> <p>Discussion</p> <p>Despite ongoing research, many challenges remain in the characterization of sleep disturbances and its correlates. Future mapping of the biological dimensions, natural history, as well as the behavioral and drug-related aspects of sleep disturbances in a representative population samples is clearly needed.</p

High-Yield Expression of Heterologous [FeFe] Hydrogenases in Escherichia coli

BACKGROUND: The realization of hydrogenase-based technologies for renewable H(2) production is presently limited by the need for scalable and high-yielding methods to supply active hydrogenases and their required maturases. PRINCIPAL FINDINGS: In this report, we describe an improved Escherichia coli-based expression system capable of producing 8-30 mg of purified, active [FeFe] hydrogenase per liter of culture, volumetric yields at least 10-fold greater than previously reported. Specifically, we overcame two problems associated with other in vivo production methods: low protein yields and ineffective hydrogenase maturation. The addition of glucose to the growth medium enhances anaerobic metabolism and growth during hydrogenase expression, which substantially increases total yields. Also, we combine iron and cysteine supplementation with the use of an E. coli strain upregulated for iron-sulfur cluster protein accumulation. These measures dramatically improve in vivo hydrogenase activation. Two hydrogenases, HydA1 from Chlamydomonas reinhardtii and HydA (CpI) from Clostridium pasteurianum, were produced with this improved system and subsequently purified. Biophysical characterization and FTIR spectroscopic analysis of these enzymes indicate that they harbor the H-cluster and catalyze H(2) evolution with rates comparable to those of enzymes isolated from their respective native organisms. SIGNIFICANCE: The production system we describe will facilitate basic hydrogenase investigations as well as the development of new technologies that utilize these prolific H(2)-producing enzymes. These methods can also be extended for producing and studying a variety of oxygen-sensitive iron-sulfur proteins as well as other proteins requiring anoxic environments