Vitamin B3, nicotinamide,enhances mitochondrial metabolism to promote differentiation of the retinal pigment epithelium

In the mammalian retina, a metabolic ecosystem exists in which photoreceptors acquire glucose from the choriocapillaris with the help of the retinal pigment epithelium (RPE). While the photoreceptor cells are primarily glycolytic, exhibiting Warburg-like metabolism, the RPE is reliant on mitochondrial respiration. However, the ways in which mitochondrial metabolism affect RPE cellular functions are not clear. We first used the human RPE cell line, ARPE-19, to examine mitochondrial metabolism in the context of cellular differentiation. We show that nicotinamide induced rapid differentiation of ARPE-19 cells, which was reversed by removal of supplemental nicotinamide. During the nicotinamide-induced differentiation, we observed using quantitative PCR, Western blotting, electron microscopy, and metabolic respiration and tracing assays that (1) mitochondrial gene and protein expression increased, (2) mitochondria became larger with more tightly folded cristae, and (3) mitochondrial metabolism was enhanced. In addition, we show that primary cultures of human fetal RPE cells responded similarly in the presence of nicotinamide. Furthermore, disruption of mitochondrial oxidation of pyruvate attenuated the nicotinamide-induced differentiation of the RPE cells. Together, our results demonstrate a remarkable effect of nicotinamide on RPE metabolism. We also identify mitochondrial respiration as a key contributor to the differentiated state of the RPE and thus to many of the RPE functions that are essential for retinal health and photoreception.     

Functional activity limitation of leprosy cases in an endemic area in Indonesia and recommendations for integrated participation program in society

BackgroundLeprosy continues to be a health problem in Indonesia, with incidence reaching over 10,000 new cases by 2021. Leprosy-related disabilities cause limitation of patients’ activity and participation in social activities. To date, no studies have been conducted in Indonesia which investigates disability in terms of bodily function, structure impairment, limitations in performing daily activities, and restrictions in participation in social activities in leprosy patients. This study is aimed to determine the demographic and clinical characteristics that might affect functional activity limitations of leprosy patients in endemic areas in Indonesia.Methods and findingsA cross-sectional study was conducted on 267 retrospectively-diagnosed cases of leprosy. The Screening of Activity Limitation and Safety Awareness (SALSA) scale was used to measure functional activity limitation, which comprises five domains: vision, mobility, self-care, work with hands, and dexterity. Differences among variables were evaluated using Kruskal-Wallis and Mann-Whitney test. The mean age of participants was 51.89±13.66 years, the majority of which were men (62.5%), uneducated (48.3%), and classified as type 2 in the World Health Organization (WHO) disability grading for hands and feet (66.3% and 68.2%, respectively). Assessment using the SALSA Scale showed 28.5% of subjects were without limitation, 43.8% with mild limitation, 13.5% with moderate limitation, 9.4% with severe limitation, and 4.9% with extreme limitation. Significant differences in the total SALSA Scale were found between age groups (p = 0.014), educational level (p = 0.005), occupation (p<0.001), and WHO disability grades (p<0.001). Multivariate analysis showed that the most significant factor influencing the total score of SALSA was disability grading for feet (score = 0.31, p <0.001) followed by occupational status, disability grading for eyes, and age. Limitation of functional activity was significantly correlated to becoming unemployed with the odds 2.59.ConclusionPeople affected by leprosy are prone to have functional activity limitation, especially the elderly, uneducated, unemployed and those with multiple disabilities. If they can overcome their barriers in functional activities, they will have better occupational opportunities.     

Wasted Food: U.S. Consumers' Reported Awareness,Attitudes, and Behaviors

The U.S. wastes 31 to 40% of its post-harvest food supply, with a substantial portion of this waste occurring at the consumer level. Globally, interventions to address wasted food have proliferated, but efforts are in their infancy in the U.S. To inform these efforts and provide baseline data to track change, we performed a survey of U.S. consumer awareness, attitudes and behaviors related to wasted food. The survey was administered online to members of a nationally representative panel (N=1010), and post-survey weights were applied. The survey found widespread (self-reported) awareness of wasted food as an issue, efforts to reduce it, and knowledge about how to do so, plus moderately frequent performance of waste-reducing behaviors. Three-quarters of respondents said they discard less food than the average American. The leading motivations for waste reduction were saving money and setting an example for children, with environmental concerns ranked last. The most common reasons given for discarding food were concern about foodborne illness and a desire to eat only the freshest food. In some cases there were modest differences based on age, parental status, and income, but no differences were found by race, education, rural/urban residence or other demographic factors. Respondents recommended ways retailers and restaurants could help reduce waste. This is the first nationally representative consumer survey focused on wasted food in the U.S. It provides insight into U.S. consumers’ perceptions related to wasted food, and comparisons to existing literature. The findings suggest approaches including recognizing that many consumers perceive themselves as being already-knowledgeable and engaged, framing messages to focus on budgets, and modifying existing messages about food freshness and aesthetics. This research also suggests opportunities to shift retail and restaurant practice, and identifies critical research gaps.     

Signal Attenuation as a Rat Model of Obsessive Compulsive Disorder

In the signal attenuation rat model of obsessive-compulsive disorder (OCD), lever-pressing for food is followed by the presentation of a compound stimulus which serves as a feedback cue. This feedback is later attenuated by repeated presentations of the stimulus without food (without the rat emitting the lever-press response). In the next stage, lever-pressing is assessed under extinction conditions (i.e., no food is delivered). At this stage rats display two types of lever-presses, those that are followed by an attempt to collect a reward, and those that are not. The latter are the measure of compulsive-like behavior in the model. A control procedure in which rats do not experience the attenuation of the feedback cue serves to distinguish between the effects of signal attenuation and of extinction. The signal attenuation model is a highly validated model of OCD and differentiates between compulsive-like behaviors and behaviors that are repetitive but not compulsive. In addition the measures collected during the procedure eliminate alternative explanations for differences between the groups being tested, and are quantitative, unbiased and unaffected by inter-experimenter variability. The major disadvantages of this model are the costly equipment, the fact that it requires some technical know-how and the fact that it is time-consuming compared to other models of OCD (11 days). The model may be used for detecting the anti- or pro-compulsive effects of pharmacological and non-pharmacological manipulations and for studying the neural substrate of compulsive behavior.     

New tryptophanase inhibitors: Towards prevention of bacterial biofilm formation

Tryptophanase (tryptophan indole-lyase, Tnase, EC 4.1.99.1), a bacterial enzyme with no counterpart in eukaryotic cells, produces from L-tryptophan pyruvate, ammonia and indole. It was recently suggested that indole signaling plays an important role in the stable maintenance of multicopy plasmids. In addition, Tnase was shown to be capable of binding Rcd, a short RNA molecule involved in resolution of plasmid multimers. Binding of Rcd increases the affinity of Tnase for tryptophan, and it was proposed that indole is involved in bacteria multiplication and biofilm formation. Biofilm-associated bacteria may cause serious infections, and biofilm contamination of equipment and food, may result in expensive consequences. Thus, optimal and specific factors that interact with Tnase can be used as a tool to study the role of this multifunctional enzyme as well as antibacterial agents that may affect biofilm formation. Most known quasi-substrates inhibit Tnase at the mM range. In the present work, the mode of Tnase inhibition by the following compounds and the corresponding Ki values were: S-phenylbenzoquinone-L-tryptophan, uncompetitively, 101 μM; α-amino-2-(9,10-anthraquinone)-propanoic acid, noncompetitively, 174 μM; L-tryptophane-ethylester, competitively, 52 μM; N-acetyl-L-tryptophan, noncompetitively, 48 μM. S-phenylbenzoquinone-L-tryptophan and α-amino-2-(9,10-anthraquinone)-propanoic acid were newly synthesized.     

Effect of oseltamivir phosphate versus placebo on platelet recovery and plasma leakage in adults with dengue and thrombocytopenia; a phase 2, multicenter,double-blind,randomized trial

BackgroundThrombocytopenia, bleeding and plasma leakage are major complications of dengue. Activation of endogenous sialidases with desialylation of platelets and endothelial cells may underlie these complications. We aimed to assess the effects of the neuraminidase inhibitor oseltamivir on platelet recovery and plasma leakage in dengue.MethodsWe performed a phase 2, double-blind, multicenter, randomized trial in adult dengue patients with thrombocytopenia (<70,000/μl) and a duration of illness ≤ 6 days. Oseltamivir phosphate 75mg BID or placebo were given for a maximum of five days. Primary outcomes were the time to platelet recovery (≥ 100,000/μl) or discharge from hospital and the course of measures of plasma leakage.ResultsA total of 70 patients were enrolled; the primary outcome could be assessed in 64 patients (31 oseltamivir; 33 placebo). Time to platelet count ≥100,000/μl (n = 55) or discharge (n = 9) were similar in the oseltamivir and placebo group (3.0 days [95% confidence interval, 2.7 to 3.3] vs. 2.9 days [2.5 to 3.3], P = 0.055). The kinetics of platelet count and parameters of plasma leakage (gall bladder thickness, hematocrit, plasma albumin, syndecan-1) were also similar between the groups.DiscussionIn this trial, adjunctive therapy with oseltamivir phosphate had no effect on platelet recovery or plasma leakage parameters.Trial registrationISRCTN35227717.     

Relationship among methylation,isoprenylation, and GTP binding in 21-to 23-kDa proteins of neuroblastoma

1. Dimethylsulfoxide-induced differentiated neuroblastoma express high levels of membrane 21 to 23-kDa carboxyl methylated proteins. Relationships among methylation, isoprenylation, and GTP binding in these proteins were investigated. Protein carboxyl methylation, protein isoprenylation, and [alpha-32P]GTP binding were determined in the electrophoretically separated proteins of cells labeled with the methylation precursor [methyl-3H]methionine or with an isoprenoid precursor [3H]mevalonate. 2. A broad band of GTP-binding proteins, which overlaps with the methylated 21 to 23-kDa proteins, was detected in [alpha-32P]GTP blot overlay assays. This band of proteins was separated in two-dimensional gels into nine methylated proteins, of which four bound GTP. 3. The carboxyl-methylated 21 to 23-kDa proteins incorporated [3H]mevalonate metabolites with characteristics of protein isoprenylation. The label was not removed by organic solvents or destroyed by hydroxylamine. Incorporation of radioactivity from [3H]mevalonate was enhanced when endogenous levels of mevalonate were reduced by lovastatin, an inhibitor of mevalonate synthesis. Lovastatin blocked methylation of the 21 to 23-kDa proteins as well (greater than 70%). 4. Methylthioadenosine, a methylation inhibitor, inhibited methylation of these proteins (greater than 80%) but did not affect their labeling by [3H]mevalonate. The results suggest that methylation of the 21 to 23-kDa proteins depends on, and is subsequent to, isoprenylation. The sequence of events may be similar to that known in ras proteins, i.e., carboxyl methylation of a C-terminal cysteine that is isoprenylated. 5. Lovastatin reduced the level of small GTP-binding proteins in the membranes and increased GTP binding in the cytosol. Methylthioadensoine blocked methylation without affecting GTP binding. 6. Thus, isoprenylation appears to precede methylation and to be important for membrane association, while methylation is not required for GTP binding or membrane association. The role of methylation remains to be determined but might be related to specific interactions of the small GTP-binding proteins with other proteins.     

Food division in the Arabian babbler nest: adult choice or nestling competition?

Many studies have found that food division among nestmates isnegatively correlated with hatrhing order. The hypothesis thatfeedings are distributed according to the provisioners' selectionis compared here with the hypothesis that feedings are dividedas a consequence of nestling competition. Food distributionamong Arabian babbler nestmates was negatively correlated withhatching order and was so skewed that many last-hatched nestlingsdied as a consequence of starvation. No feeding preference wasfound between any adult and any given nestling. No differencewas found in feeding distribution among parents, partial parents,and nonparents. When an older foreign nestling was introducedinto the nest, adults fed the newcomer more intensively thantheir own offspring, implying that feeding division among nestmateswas not determined by die feeders but by the nestlings' relativeability to obtain food. In two-nestling nests, the older nestlingobtained 62% of the feedings, on average. However, followingselective feedings of the second-hatched nestling by the investigator,which equalized the two siblings' feeding amounts by the endof their second day, no difference was found between their feedingrates. The relative advantage of the older nestlings was eliminatedby introducing a barrier into the nest. Under these conditions,feedings were distributed equally among the nestmates. Sinceneither hatching order, previous priority order, nor individualidentification were used by the provisioning adults, the proximatefactor determining food division among the neslings appearsto be the result of nestling competition     

Understanding and addressing waste of food in the Kingdom of Saudi Arabia

IntroductionMultiple estimates suggest the Kingdom of Saudi Arabia (KSA) may have one of the highest rates of wasted food globally. The KSA has limited arable lands and scarce water and thus relies on extensive imports and food subsidies to meet food demand. Accordingly, waste and loss of food are a significant concern for food security.Materials and methodsA narrative literature review was performed to identify the available information relevant to characterizing the context, magnitude of food wasted in the KSA, key contributing factors, and existing interventions and recommendations.ResultsEstimates of annual per capita waste of food ranged from 165 kg to 511 kg. Given the country's relatively limited agricultural production, the consumer and retail levels are primary targets for intervention. Key contributors to waste include culture, food valuation, policy and industry factors, and awareness and concern. The country is at an early stage of developing responses. We build upon existing approaches and recommendations, with particular emphasis on the potential role of agricultural extension staff in addressing the issue, and highlight research needs.ConclusionsGiven the potentially exceptional levels of wasted food in the KSA and the extensive evidence gaps, there is a great need for further research and action. Our review and synthesis presents numerous opportunities to advance innovative waste reduction approaches in the country, with particular relevance for other parts of the Middle East and other areas early in their efforts to address waste of food.