Levels of Cholesterol in Small LDL Particles Predict Atherosclerosis Progression and Incident CHD in the HDL-Atherosclerosis Treatment Study (HATS)

Objective

Test whether angiographically-documented changes in percent stenosis and clinical endpoints (coronary-related deaths, myocardial infarctions, stroke, revascularization for worsening ischemia) in the HDL-Atherosclerosis Treatment Study (HATS) were attributable to specific LDL-subclasses.

Methods

Gradient gel electrophoresis of on-study LDL-subclass cholesterol concentrations were measured in 32 placebo, 33 simvastatin-niacin, 38 antioxidant, and 39 simvastatin-niacin & antioxidant treated participants. The prespecified primary end point was the mean change per patient from the initial arteriogram to the final arteriogram in the percent stenosis caused by the most severe lesion in each of the nine proximal coronary segments.

Results

The change in the percent stenosis of the most severe proximal lesions increased in association with higher concentrations of the small LDL subfractions LDL-IIIb (24.2–24.6 nm) and LDL-IVa (23.3–24.1 nm) before (both P = 0.002) and after (P = 0.01 and P = 0.03 respectively) adjustment for treatment group and on-study HDL-cholesterol, LDL-cholesterol, and triglyceride concentrations. The associations appeared specific to lesions with <30% baseline stenosis. When adjusted for age, sex, baseline BMI and cigarette use, the odds for primary clinical endpoints (death from coronary causes, nonfatal myocardial infarction, stroke, or revascularization for worsening ischemia) were significantly greater in subjects with higher on-study LDL-IIIb levels both before (P = 0.01) and after (P = 0.03) adjustment for treatment group and the standard lipid values.

Conclusions

Plasma LDL-IIIb cholesterol concentrations were related to changes in coronary artery stenosis and cardiovascular events in patients with coronary artery disease and low HDL-cholesterol.

Trial Registration

ClinicalTrials.gov {"type":"clinical-trial","attrs":{"text":"NCT00000553","term_id":"NCT00000553"}}NCT00000553     

Loggerhead Turtles (Caretta caretta) Use Vision to Forage on Gelatinous Prey in Mid-Water

Identifying characteristics of foraging activity is fundamental to understanding an animals’ lifestyle and foraging ecology. Despite its importance, monitoring the foraging activities of marine animals is difficult because direct observation is rarely possible. In this study, we use an animal-borne imaging system and three-dimensional data logger simultaneously to observe the foraging behaviour of large juvenile and adult sized loggerhead turtles (Caretta caretta) in their natural environment. Video recordings showed that the turtles foraged on gelatinous prey while swimming in mid-water (i.e., defined as epipelagic water column deeper than 1 m in this study). By linking video and 3D data, we found that mid-water foraging events share the common feature of a marked deceleration phase associated with the capture and handling of the sluggish prey. Analysis of high-resolution 3D movements during mid-water foraging events, including presumptive events extracted from 3D data using deceleration in swim speed as a proxy for foraging (detection rate = 0.67), showed that turtles swam straight toward prey in 171 events (i.e., turning point absent) but made a single turn toward the prey an average of 5.7±6.0 m before reaching the prey in 229 events (i.e., turning point present). Foraging events with a turning point tended to occur during the daytime, suggesting that turtles primarily used visual cues to locate prey. In addition, an incident of a turtle encountering a plastic bag while swimming in mid-water was recorded. The fact that the turtle’s movements while approaching the plastic bag were analogous to those of a true foraging event, having a turning point and deceleration phase, also support the use of vision in mid-water foraging. Our study shows that integrated video and high-resolution 3D data analysis provides unique opportunities to understand foraging behaviours in the context of the sensory ecology involved in prey location.     

The Global Epidemiology and Contribution of Cannabis Use and Dependence to the Global Burden of Disease: Results from the GBD 2010 Study

AimsEstimate the prevalence of cannabis dependence and its contribution to the global burden of disease.MethodsSystematic reviews of epidemiological data on cannabis dependence (1990-2008) were conducted in line with PRISMA and meta-analysis of Observational Studies in Epidemiology (MOOSE) guidelines. Culling and data extraction followed protocols, with cross-checking and consistency checks. DisMod-MR, the latest version of generic disease modelling system, redesigned as a Bayesian meta-regression tool, imputed prevalence by age, year and sex for 187 countries and 21 regions. The disability weight associated with cannabis dependence was estimated through population surveys and multiplied by prevalence data to calculate the years of life lived with disability (YLDs) and disability-adjusted life years (DALYs). YLDs and DALYs attributed to regular cannabis use as a risk factor for schizophrenia were also estimated.ResultsThere were an estimated 13.1 million cannabis dependent people globally in 2010 (point prevalence0.19% (95% uncertainty: 0.17-0.21%)). Prevalence peaked between 20-24 yrs, was higher in males (0.23% (0.2-0.27%)) than females (0.14% (0.12-0.16%)) and in high income regions. Cannabis dependence accounted for 2 million DALYs globally (0.08%; 0.05-0.12%) in 2010; a 22% increase in crude DALYs since 1990 largely due to population growth. Countries with statistically higher age-standardised DALY rates included the United States, Canada, Australia, New Zealand and Western European countries such as the United Kingdom; those with lower DALY rates were from Sub-Saharan Africa-West and Latin America. Regular cannabis use as a risk factor for schizophrenia accounted for an estimated 7,000 DALYs globally.ConclusionCannabis dependence is a disorder primarily experienced by young adults, especially in higher income countries. It has not been shown to increase mortality as opioid and other forms of illicit drug dependence do. Our estimates suggest that cannabis use as a risk factor for schizophrenia is not a major contributor to population-level disease burden.     

Vertical stratification of a temperate forest caterpillar community in eastern North America

Vertical niche partitioning might be one of the main driving forces explaining the high diversity of forest ecosystems. However, the forest’s vertical dimension has received limited investigation, especially in temperate forests. Thus, our knowledge about how communities are vertically structured remains limited for temperate forest ecosystems. In this study, we investigated the vertical structuring of an arboreal caterpillar community in a temperate deciduous forest of eastern North America. Within a 0.2-ha forest stand, all deciduous trees ≥ 5 cm diameter at breast height (DBH) were felled and systematically searched for caterpillars. Sampled caterpillars were assigned to a specific stratum (i.e. understory, midstory, or canopy) depending on their vertical position and classified into feeding guild as either exposed feeders or shelter builders (i.e. leaf rollers, leaf tiers, webbers). In total, 3892 caterpillars representing 215 species of butterflies and moths were collected and identified. While stratum had no effect on caterpillar density, feeding guild composition changed significantly with shelter-building caterpillars becoming the dominant guild in the canopy. Species richness and diversity were found to be highest in the understory and midstory and declined strongly in the canopy. Family and species composition changed significantly among the strata; understory and canopy showed the lowest similarity. Food web analyses further revealed an increasing network specialization towards the canopy, caused by an increase in specialization of the caterpillar community. In summary, our study revealed a pronounced stratification of a temperate forest caterpillar community, unveiling a distinctly different assemblage of caterpillars dwelling in the canopy stratum.     

Oviposition preferences and antennal size in carrion flies

Carrion-feeding flies use odours emanating from the decomposing corpse as cues for oviposition and are described as generalists because the larvae feed on the corpses of diverse species. Whereas several features of the corpse may influence the oviposition choices of these flies, it is not known whether there is a preference for a particular species of corpse. We provided carrion flies with ovipositional (and feeding) choices in a field experiment, in which various odour sources were presented simultaneously. We found novel evidence of broadly consistent choices of carrion by flies from four families. Traps baited with decaying fish flesh captured the greatest number of individuals, whereas traps baited with decaying pig liver typically attracted the least. We also asked whether individuals captured in the various baits vary in antennal size, perhaps reflecting different capacities for odour detection. There was a trend for individuals of Lucilia sericata Meigen (Diptera: Calliphoridae) and the platystomatid collected from the traps baited with pig liver to have significantly larger antennae, whereas individuals of Muscina stabulans (Fallen) (Diptera: Muscidae) captured in traps baited with marine fish flesh had relatively longer antennae for their body size. Our data reveal a more nuanced pattern of oviposition behaviour in these generalist carrion flies, which may reflect differences in their preference of carrion with different nutrients, and in their capacity to detect particular odours.     

Structure and activity of the NAD(P)+‐dependent succinate semialdehyde dehydrogenase YneI from Salmonella typhimurium

Aldehyde dehydrogenases are found in all organisms and play an important role in the metabolic conversion and detoxification of endogenous and exogenous aldehydes. Genomes of many organisms including Escherichia coli and Salmonella typhimurium encode two succinate semialdehyde dehydrogenases with low sequence similarity and different cofactor preference (YneI and GabD). Here, we present the crystal structure and biochemical characterization of the NAD(P)⁺‐dependent succinate semialdehyde dehydrogenase YneI from S. typhimurium. This enzyme shows high activity and affinity toward succinate semialdehyde and exhibits substrate inhibition at concentrations of SSA higher than 0.1 mM. YneI can use both NAD⁺ and NADP⁺ as cofactors, although affinity to NAD⁺ is 10 times higher. High resolution crystal structures of YneI were solved in a free state (1.85 Å) and in complex with NAD⁺ (1.90 Å) revealing a two domain protein with the active site located in the interdomain interface. The NAD⁺ molecule is bound in the long channel with its nicotinamide ring positioned close to the side chain of the catalytic Cys268. Site‐directed mutagenesis demonstrated that this residue, as well as the conserved Trp136, Glu365, and Asp426 are important for activity of YneI, and that the conserved Lys160 contributes to the enzyme preference to NAD⁺. Our work has provided further insight into the molecular mechanisms of substrate selectivity and activity of succinate semialdehyde dehydrogenases. © 2012 Wiley Periodicals, Inc.     

Human Core Temperature Responses during Exercise and Subsequent Recovery: An Important Interaction between Diurnal Variation and Measurement Site

Chronobiological investigations into core temperature during and after exercise can involve ambulatory measurements of intestinal temperature during actual competitions, esophageal temperature measurements in laboratory simulations, or rectal temperature, which can be measured in both the field and laboratory. These sites have yet to be compared during both morning and afternoon exercise and subsequent recovery. At 08∶00 and 17∶00 h, seven recreationally active males exercised at 70% peak oxygen uptake for 30 min and then recovered passively for 30 min. During the experiment, esophageal, rectal, intestinal, and skin temperatures, plus sweat loss, heart rate, and ratings of perceived exertion (RPE), were monitored. We found that the diurnal variation in intestinal temperature responses (0.45±0.32°C; mean±SD) was significantly larger compared with rectal (0.33±0.24°C) and, particularly, esophageal temperature responses (0.21±0.20°C; p= 0.019). This reflected a greater difference of 0.25–0.40°C between the esophagus and the other two sites in the afternoon, compared to inter‐site differences of only 0.13–0.16°C in the morning. Diurnal variation was small for skin temperature, heart rate, sweat loss, and RPE responses during exercise (p>0.05). Our data suggest that the relative differences between intestinal, rectal, and esophageal temperature during exercise and subsequent recovery depend on time of day to the extent that inferences from studies on experimental and applied chronobiology will be affected.     

Evolution of Bacterial-Like Phosphoprotein Phosphatases in Photosynthetic Eukaryotes Features Ancestral Mitochondrial or Archaeal Origin and Possible Lateral Gene Transfer

Protein phosphorylation is a reversible regulatory process catalyzed by the opposing reactions of protein kinases and phosphatases, which are central to the proper functioning of the cell. Dysfunction of members in either the protein kinase or phosphatase family can have wide-ranging deleterious effects in both metazoans and plants alike. Previously, three bacterial-like phosphoprotein phosphatase classes were uncovered in eukaryotes and named according to the bacterial sequences with which they have the greatest similarity: Shewanella-like (SLP), Rhizobiales-like (RLPH), and ApaH-like (ALPH) phosphatases. Utilizing the wealth of data resulting from recently sequenced complete eukaryotic genomes, we conducted database searching by hidden Markov models, multiple sequence alignment, and phylogenetic tree inference with Bayesian and maximum likelihood methods to elucidate the pattern of evolution of eukaryotic bacterial-like phosphoprotein phosphatase sequences, which are predominantly distributed in photosynthetic eukaryotes. We uncovered a pattern of ancestral mitochondrial (SLP and RLPH) or archaeal (ALPH) gene entry into eukaryotes, supplemented by possible instances of lateral gene transfer between bacteria and eukaryotes. In addition to the previously known green algal and plant SLP1 and SLP2 protein forms, a more ancestral third form (SLP3) was found in green algae. Data from in silico subcellular localization predictions revealed class-specific differences in plants likely to result in distinct functions, and for SLP sequences, distinctive and possibly functionally significant differences between plants and nonphotosynthetic eukaryotes. Conserved carboxyl-terminal sequence motifs with class-specific patterns of residue substitutions, most prominent in photosynthetic organisms, raise the possibility of complex interactions with regulatory proteins.Reversible protein phosphorylation is a posttranslational mechanism central to the proper function of living organisms (Brautigan, 2013). Governed by two large groups of enzymes, protein kinases and protein phosphatases, this mechanism has been suggested to regulate upwards of 70% of all eukaryotic proteins (Olsen et al., 2010). Protein phosphatases represent one-half of this dynamic regulatory system and have been shown to be highly regulated proteins themselves (Roy and Cyert, 2009; Shi, 2009; Uhrig et al., 2013). Classically, protein phosphatases have been placed into four families defined by a combination of their catalytic mechanisms, metal ion requirements, and phosphorylated amino acid targets (Kerk et al., 2008). These four families are the phosphoprotein phosphatases (PPPs), metallo-dependent protein phosphatases, protein Tyr phosphatases, and Asp-based phosphatases. The PPP protein phosphatases, best known to include PP1, PP2A, PP2B, and PP4 to PP7 (Kerk et al., 2008; Shi, 2009), have been found to regulate a diverse number of biological processes in plants ranging from cell signaling (Ahn et al., 2011; Di Rubbo et al., 2011; Tran et al., 2012) to metabolism (Heidari et al., 2011; Leivar et al., 2011) and hormone biosynthesis (Skottke et al., 2011). The classical PPP protein phosphatase family has been expanded to include three novel classes that show greatest similarity to PPP-like protein phosphatases of prokaryotic origin (Andreeva and Kutuzov, 2004; Uhrig and Moorhead, 2011a; Uhrig et al., 2013). These bacterial-like phosphatase classes were annotated as Shewanella-like (SLP) phosphatases, Rhizobiales-like (RLPH) phosphatases, and ApaH-like (ALPH) phosphatases based on their similarity to prokaryotic sequences from these respective sources (Andreeva and Kutuzov, 2004). Recent characterization of the SLP phosphatases from Arabidopsis (Arabidopsis thaliana) provided biochemical evidence of insensitivity to the classic PPP protein phosphatase inhibitors okadaic acid and microcystin in addition to revealing a lack of genetic redundancy across sequenced plant genomes (Uhrig and Moorhead, 2011a).The characterization of eukaryotic protein evolution can provide insight into individual protein or protein class conservation across the domains of life for biotechnological applications in addition to furthering our understanding of how multicellular life evolved. In particular, investigation into the evolution of key signaling proteins, such as protein kinases and phosphatases from plants, can have wide-ranging agribiotechnological and medical potential. This can include the development of healthier, disease- or stress-resistant crops in addition to treatments for parasitic organisms such as Plasmodium spp. (malaria; Patzewitz et al., 2013) and other chromoalveolates (Kutuzov and Andreeva, 2008; Uhrig and Moorhead, 2011b) that are derived from photosynthetic eukaryotes and maintain a remnant chloroplast (apicoplast; Le Corguillé et al., 2009; Janouskovec et al., 2010; Kalanon and McFadden, 2010; Walker et al., 2011). The existence of proteins that are conserved across diverse eukaryotic phyla but absent in metazoa, such as the majority of bacterial-like PPP protein phosphatases described here, presents unique research opportunities.Conventional understanding of the acquisition by eukaryotes of prokaryotic genes and proteins largely involves ancient endosymbiotic gene transfer events stemming from primary endosymbiosis of α-Proteobacteria and Cyanobacteria to form eukaryotic mitochondria and chloroplasts, respectively (Keeling and Palmer, 2008; Dorrell and Smith, 2011; Tirichine and Bowler, 2011). Over time, however, it has become apparent that alternative modes of eukaryotic gene and protein acquisition exist, such as independent horizontal or lateral gene transfer (LGT) events (Keeling and Palmer, 2008; Keeling, 2009). Targeted studies of protein evolution have seen a steady rise in documented LGT events across a wide variety of eukaryotic organisms, including photosynthetic eukaryotes (Derelle et al., 2006; Raymond and Kim, 2012; Schönknecht et al., 2013), nematodes (Mayer et al., 2011), arthropods (Acuña et al., 2012), fungi (Wenzl et al., 2005), amoebozoa (Clarke et al., 2013), and oomycetes (Belbahri et al., 2008). Each instance documents the integration of a bacterial gene(s) into a eukaryotic organism, seemingly resulting in an adaptive advantage(s) important to organism survival.Utilizing a number of in silico bioinformatic techniques and available sequenced genomes, the molecular evolution of three bacterial-like PPP classes found in eukaryotes is revealed to involve ancient mitochondrial or archaeal origin plus additional possible LGT events. A third, more ancient group of SLP phosphatases (SLP3 phosphatases) is defined in green algae. Subcellular localization predictions reveal distinctive subsets of bacterial-like PPPs, which may correlate with altered functions. In addition, the large sequence collections compiled here have allowed the elucidation of two highly conserved C-terminal domain motifs, which are specific to each bacterial-like PPP class and whose differences are particularly pronounced in photosynthetic eukaryotes. Together, these findings substantially expand our knowledge of the molecular evolution of the bacterial-like PPPs and point the way toward attractive future research avenues.