Evaluation of dihydrooroidin as an antifouling additive in marine paint

Methods used to deter biofouling of underwater structures and marine vessels present a serious environmental issue and are both problematic and costly for government and commercial marine vessels worldwide. Current antifouling methods include compounds that are toxic to aquatic wildlife and marine ecosystems. Dihydrooroidin (DHO) was shown to completely inhibit Halomonas pacifica biofilms at 100 μM in a static biofilm inhibition assay giving precedence for the inhibition of other marine biofilm-forming organisms. Herein we present DHO as an effective paint-based, non-cytotoxic, antifouling agent against marine biofouling processes in a marine mesocosm.     

The P2Y 13 Met-158-Thr polymorphism, which is in linkage disequilibrium with the P2Y 12 locus, is not associated with acute myocardial infarction

BACKGROUND AND AIMS: The aims of this study were to investigate (1) if P2Y(12) polymorphisms defining the P2Y(12) H2 allele are associated with any other SNPs that may explain the previously reported association with increased ADP induced platelet activation and association with peripheral arterial disease and coronary artery disease and (2) if such variants are associated with acute myocardial infarction (AMI) or classical risk factors for AMI. METHODS AND RESULTS: The P2Y(13) Met-158-Thr polymorphism was found to be in linkage disequilibrium (LD) with the P2Y(12) H2 haplotype (all examined SNPs: D' = 1.0, r(2) = 0.936-1.0), defining a novel P2Y(12) H2/P2Y(13) Thr-158 haplotype. Genotyping of an AMI case control population (n = 1244 cases, 2488 controls) revealed no association of the P2Y(13) Thr-158 allele with AMI (OR = 0.96, 95% C.I. 0.82-1.12, P = 0.63). Also, no differences between the genotype frequencies of P2Y(13) Met-158-Met and Met-158-Thr/Thr-158-Thr were seen in AMI case-control subpopulations (early onset AMI OR = 1.06, 95% C.I. 0.85-1.31, P = 0.62); family history of AMI (OR = 0.98, 95% C.I. 0.78-1.22, P = 0.83) nor in early onset AMIs with family history of AMI (OR = 1.0, 95% C.I. 0.74-1.36, P = 1.0). Genotyping of the P2Y(13) Met-158-Thr polymorphism in a population based sample (n = 6055) revealed no association with cardiovascular risk factors. In addition, the P2Y(13) Met-158-Thr polymorphism was genotyped in a diabetes case-control population, and associations were found neither with DM nor with any examined DM risk factors. CONCLUSION GENOTYPING: The P2Y(13) Met-158-Thr polymorphism is in tight LD with the P2Y(12) locus but is not associated with AMI or classical cardiovascular risk factors.     

Kinetic consequences of covalent linkage of DNA binding polyamides

Polyamides composed of N-methylpyrrole (Py) and N-methylimidazole (Im) subunits can bind in the minor groove of DNA at predetermined sequences with subnanomolar affinity and high specificity. Covalent linkage of polymer subunits using a gamma-aminobutyric acid linker has been shown to increase both the affinity and specificity of polyamides. Using a fluorescence detected stopped-flow assay, we have studied the differences in association and dissociation kinetics of a series of polyamides representing unlinked, hairpin and cyclic analogues of the four ring polyamide ImPyPyPy-beta-Dp. Whereas the large differences seen in the equilibrium association constants between the unlinked and covalently linked polyamides are primarily due to higher association rate constants, discrimination between matched and mismatched sites by each polyamide can be ascribed in large part to differences in their dissociation rate constants. The consequences of this kinetic behavior for future design are discussed.     

Crystal structures of nucleosome core particles in complex with minor groove DNA-binding ligands

We determined the crystal structures of three nucleosome core particles in complex with site-specific DNA-binding ligands, the pyrrole-imidazole polyamides. While the structure of the histone octamer and its interaction with the DNA remain unaffected by ligand binding, nucleosomal DNA undergoes significant structural changes at the ligand-binding sites and in adjacent regions to accommodate the ligands. Our findings suggest that twist diffusion occurs over long distances through tightly bound nucleosomal DNA. This may be relevant to the mechanism of ATP-dependent and spontaneous nucleosome translocation, and to the effect of bound factors on nucleosome dynamics.     

Regulation of the Rab5 GTPase-activating protein RN-tre by the dual specificity phosphatase Cdc14A in human cells

The Cdc14 family of dual specificity phosphatases regulates key mitotic events in the eukaryotic cell cycle. Although extensively characterized in yeast, little is known about the function of mammalian Cdc14 family members. Here we report a genetic substrate-trapping system designed to identify substrates of the human Cdc14A (hCdc14A) phosphatase. Using this approach, we identify RN-tre, a GTPase-activating protein for the Rab5 GTPase, as a novel physiological target of hCdc14A. As a Rab5 GTPase-activating protein, RN-tre has previously been implicated in control of intracellular membrane trafficking. We find that RN-tre forms a stable complex with the catalytically inactive hCdc14A C278S mutant but not with the wild type protein in human cells, indicative of a substrate/enzyme interaction. In support, we show that RN-tre is regulated by cell cycle-dependent phosphorylation peaking at mitosis, which can be antagonized by hCdc14A activity in vitro as well as in vivo. Furthermore, we show that RN-tre phosphorylation is critical for efficient hCdc14A association and that RN-tre binding can be displaced by tungstate, a competitive inhibitor that binds to the active site of hCdc14A. Consistent with the preference of hCdc14A for phosphorylations mediated by proline-directed kinases, we find that RN-tre is a direct substrate of cyclin-dependent kinase. Finally, phosphorylation of RN-tre appears to finely modulate its catalytic activity. Our findings reveal a novel connection between the cell cycle machinery and the endocytic pathway.     

WDR12, a Member of Nucleolar PeBoW-Complex,Is Up-Regulated in Failing Hearts and Causes Deterioration of Cardiac Function

Aims

In a recent genome-wide association study, WD-repeat domain 12 (WDR12) was associated with early-onset myocardial infarction (MI). However, the function of WDR12 in the heart is unknown.

Methods and Results

We characterized cardiac expression of WDR12, used adenovirus-mediated WDR12 gene delivery to examine effects of WDR12 on left ventricular (LV) remodeling, and analyzed relationship between MI associated WDR12 allele and cardiac function in human subjects. LV WDR12 protein levels were increased in patients with dilated cardiomyopathy and rats post-infarction. In normal adult rat hearts, WDR12 gene delivery into the anterior wall of the LV decreased interventricular septum diastolic and systolic thickness and increased the diastolic and systolic diameters of the LV. Moreover, LV ejection fraction (9.1%, P<0.05) and fractional shortening (12.2%, P<0.05) were declined. The adverse effects of WDR12 gene delivery on cardiac function were associated with decreased cellular proliferation, activation of p38 mitogen–activated protein kinase (MAPK)/heat shock protein (HSP) 27 pathway, and increased protein levels of Block of proliferation 1 (BOP1), essential for ribosome biogenesis. Post-infarction WDR12 gene delivery decreased E/A ratio (32%, P<0.05) suggesting worsening of diastolic function. In human subjects, MI associated WDR12 allele was associated significantly with diastolic dysfunction and left atrial size.

Conclusions

WDR12 triggers distinct deterioration of cardiac function in adult rat heart and the MI associated WDR12 variant is associated with diastolic dysfunction in human subjects.     

Fall Risk Awareness and Safety Precautions Taken by Older Community-Dwelling Women and Men—A Qualitative Study Using Focus Group Discussions

Introduction

Daily life requires frequent estimations of the risk of falling and the ability to avoid a fall. The objective of this study was to explore older women’s and men’s understanding of fall risk and their experiences with safety precautions taken to prevent falls.

Methods

A qualitative study with focus group discussions was conducted. Eighteen community-dwelling people [10 women and 8 men] with and without a history of falls were purposively recruited. Participants were divided into two groups, and each group met four times. A participatory and appreciative action and reflection approach was used to guide the discussions. All discussions were audio recorded and transcribed verbatim. Data were analysed by qualitative content analysis, and categories were determined inductively.

Findings

Three categories describing the process of becoming aware of fall risks in everyday life were identified: 1] Facing various feelings, 2] Recognizing one’s fall risk, and 3] Taking precautions. Each category comprised several subcategories. The comprehensive theme derived from the categories was “Safety precautions through fall risk awareness”. Three strategies of ignoring [continuing a risky activity], gaining insight [realizing the danger in a certain situation], and anticipating [thinking ahead and acting in advance] were related to all choices of actions and could fluctuate in the same person in different contexts.

Conclusions

The fall risk awareness process might be initiated for various reasons and can involve different feelings and precautions as well as different strategies. This finding highlights that there are many possible channels to reach older people with information about fall risk and fall prevention, including the media and their peers. The findings offer a deeper understanding of older peoples’ conceptualizations about fall risk awareness and make an important contribution to the development and implementation of fall prevention programmes.     

Orthostatic Changes in Hemodynamics and Cardiovascular Biomarkers in Dysautonomic Patients

Background

Impaired autonomic control of postural homeostasis results in orthostatic intolerance. However, the role of neurohormones in orthostatic intolerance has not been explained.

Methods

Six-hundred-and-seventy-one patients (299 males; 55±22 years) with unexplained syncope underwent head-up tilt (HUT) with serial blood sampling. Systolic blood pressure (SBP) and heart rate (HR) supine, after 3min, and lowest BP/highest HR during HUT were recorded. Plasma levels of epinephrine, norepinephrine, renin, C-terminal-pro-arginine-vasopressin (CT-proAVP), C-terminal- endothelin-1 (CT-proET-1), and mid-regional-fragment of pro-atrial-natriuretic-peptide (MR-proANP) were determined at supine and 3min of HUT. Multivariate-adjusted logistic regression model was applied to compare 1^st (reference) with 4^th quartile of 3 min and maximal ΔSBP/ΔHR (i.e. pronounced hypotension or tachycardia) vs. changes in neuroendocrine biomarkers, respectively.

Results

Higher resting CT-proET-1 predicted BP fall at 3min (Odds ratio (OR) per 1 SD: 1.62, 95%CI 1.18–2.22; p = 0.003), and max BP fall during HUT (1.82, 1.28–2.61; p = 0.001). Higher resting CT-proAVP predicted BP fall at 3min (1.33, 1.03–1.73; p = 0.03), which was also associated with increase in CT-proAVP (1.86, 1.38–2.51; p = 0.00005) and epinephrine (1.47, 1.12–1.92; p = 0.05) during HUT. Lower resting MR-proANP predicted tachycardia at 3min (0.37, 0.24–0.59; p = 0.00003), and max tachycardia during HUT (0.47, 0.29–0.77; p = 0.002). Further, tachycardia during HUT was associated with increase in epinephrine (1.60, 1.15–2.21; p = 0.005), and norepinephrine (1.87, 1.38–2.53; p = 0.005).

Conclusions

Resting CT-proET-1 and CT-proAVP are increased in orthostatic hypotension, while resting MR-proANP is decreased in postural tachycardia. Moreover, early BP fall during orthostasis evokes increase in CT-proAVP and epinephrine, while postural tachycardia is associated with increase in norepinephrine and epinephrine.     

The chemical synthesis and antibiotic activity of a diverse library of 2-aminobenzimidazole small molecules against MRSA and multidrug-resistant A. baumannii

Multidrug-resistant bacterial infections continue to be a rising global health concern. Herein is described the development of a class of novel 2-aminobenzimidazoles with antibiotic activity. These active 2-aminobenzimidazoles retain their antibiotic activity against several strains of multidrug-resistant Staphylococcus aureus and Acinetobacter baumannii when compared to susceptible strains.