The Potential of a High Protein-Low Carbohydrate Diet to Preserve Intrahepatic Triglyceride Content in Healthy Humans

Background

Protein supplementation has been shown to reduce the increases in intrahepatic triglyceride (IHTG) content induced by acute hypercaloric high-fat and high-fructose diets in humans.

Objective

To assess the effect of a 12-wk iso-energetic high protein-low carbohydrate (HPLC) diet compared with an iso-energetic high carbohydrate-low protein (HCLP) diet on IHTG content in healthy non-obese subjects, at a constant body weight.

Design

Seven men and nine women [mean ± SD age: 24±5 y; BMI: 22.9±2.1 kg/m²] were randomly allocated to a HPLC [30/35/35% of energy (En%) from protein/carbohydrate/fat] or a HCLP (5/60/35 En%) diet by stratification on sex, age and BMI. Dietary guidelines were prescribed based on individual daily energy requirements. IHTG content was measured by ¹H-magnetic resonance spectroscopy before and after the dietary intervention.

Results

IHTG content changed in different directions with the HPLC (CH₂H₂O: 0.23±0.17 to 0.20±0.10; IHTG%: 0.25±0.20% to 0.22±0.11%) compared with the HCLP diet (CH₂H₂O: 0.34±0.20 vs. 0.38±0.21; IHTG%: 0.38±0.22% vs. 0.43±0.24%), which resulted in a lower IHTG content in the HPLC compared with the HCLP diet group after 12 weeks, which almost reached statistical significance (P = 0.055).

Conclusions

A HPLC vs. a HCLP diet has the potential to preserve vs. enlarge IHTG content in healthy non-obese subjects at a constant body weight.

Trial Registration

Clinicaltrials.gov {"type":"clinical-trial","attrs":{"text":"NCT01551238","term_id":"NCT01551238"}}NCT01551238     

Does the Method of Weight Loss Effect Long-Term Changes in Weight,Body Composition or Chronic Disease Risk Factors in Overweight or Obese Adults? A Systematic Review

Background

Differences in biological changes from weight loss by energy restriction and/or exercise may be associated with differences in long-term weight loss/regain.

Objective

To assess the effect of weight loss method on long-term changes in weight, body composition and chronic disease risk factors.

Data Sources

PubMed and Embase were searched (January 1990-October 2013) for studies with data on the effect of energy restriction, exercise (aerobic and resistance) on long-term weight loss. Twenty articles were included in this review.

Study Eligibility Criteria

Primary source, peer reviewed randomized trials published in English with an active weight loss period of >6 months, or active weight loss with a follow-up period of any duration, conducted in overweight or obese adults were included.

Study Appraisal and Synthesis Methods

Considerable heterogeneity across trials existed for important study parameters, therefore a meta-analysis was considered inappropriate. Results were synthesized and grouped by comparisons (e.g. diet vs. aerobic exercise, diet vs. diet + aerobic exercise etc.) and study design (long-term or weight loss/follow-up).

Results

Forty percent of trials reported significantly greater long-term weight loss with diet compared with aerobic exercise, while results for differences in weight regain were inconclusive. Diet+aerobic exercise resulted in significantly greater weight loss than diet alone in 50% of trials. However, weight regain (∼55% of loss) was similar in diet and diet+aerobic exercise groups. Fat-free mass tended to be preserved when interventions included exercise.     

Pharmacodynamics of Antimicrobials against Mycoplasma mycoides mycoides Small Colony, the Causative Agent of Contagious Bovine Pleuropneumonia

Background

Mycoplasma mycoides subspecies mycoides Small Colony (MmmSC) is the causative agent of Contagious Bovine Pleuropneumonia (CBPP), a disease of substantial economic importance in sub-Saharan Africa. Failure of vaccination to curtail spread of this disease has led to calls for evaluation of the role of antimicrobials in CBPP control. Three major classes of antimicrobial are effective against mycoplasmas, namely tetracyclines, fluoroquinolones and macrolides. Therefore, the objectives of this study were to determine the effector kinetics of oxytetracycline, danofloxacin and tulathromycin against two MmmSC field strains in artificial medium and adult bovine serum.

Methods

Minimum inhibitory concentrations (MIC) were determined for oxytetracycline, danofloxacin and tulathromycin against MmmSC strains B237 and Tan8 using a macrodilution technique, and time-kill curves were constructed for various multiples of the MIC over a 24 hour period in artificial medium and serum. Data were fitted to sigmoid E_max models to obtain 24 hour-area under curve/MIC ratios for mycoplasmastasis and, where appropriate, for mycoplasmacidal activity and virtual mycoplasmal elimination.

Results

Minimum inhibitory concentrations against B237 were 20-fold higher, 2-fold higher and approximately 330-fold lower in serum than in artificial medium for oxytetracycline, danofloxacin and tulathromycin, respectively. Such differences were mirrored in experiments using Tan8. Oxytetracycline was mycoplasmastatic against both strains in both matrices. Danofloxacin elicited mycoplasmacidal activity against B237 and virtual elimination of Tan8; similar maximum antimycoplasmal effects were observed in artificial medium and serum. Tulathromycin effected virtual elimination of B237 but was mycoplasmastatic against Tan8 in artificial medium. However, this drug was mycoplasmastatic against both strains in the more physiologically relevant matrix of serum.

Conclusions

Oxytetracycline, danofloxacin and tulathromycin are all suitable candidates for further investigation as potential treatments for CBPP. This study also highlights the importance of testing drug activity in biological matrices as well as artificial media.     

Towards a synthetic chloroplast

Background

The evolution of eukaryotic cells is widely agreed to have proceeded through a series of endosymbiotic events between larger cells and proteobacteria or cyanobacteria, leading to the formation of mitochondria or chloroplasts, respectively. Engineered endosymbiotic relationships between different species of cells are a valuable tool for synthetic biology, where engineered pathways based on two species could take advantage of the unique abilities of each mutualistic partner.

Results

We explored the possibility of using the photosynthetic bacterium Synechococcus elongatus PCC 7942 as a platform for studying evolutionary dynamics and for designing two-species synthetic biological systems. We observed that the cyanobacteria were relatively harmless to eukaryotic host cells compared to Escherichia coli when injected into the embryos of zebrafish, Danio rerio, or taken up by mammalian macrophages. In addition, when engineered with invasin from Yersinia pestis and listeriolysin O from Listeria monocytogenes, S. elongatus was able to invade cultured mammalian cells and divide inside macrophages.

Conclusion

Our results show that it is possible to engineer photosynthetic bacteria to invade the cytoplasm of mammalian cells for further engineering and applications in synthetic biology. Engineered invasive but non-pathogenic or immunogenic photosynthetic bacteria have great potential as synthetic biological devices.     

Statistical and Biological Gene-Lifestyle Interactions of MC4R and FTO with Diet and Physical Activity on Obesity: New Effects on Alcohol Consumption

Background

Fat mass and obesity (FTO) and melanocortin-4 receptor (MC4R) and are relevant genes associated with obesity. This could be through food intake, but results are contradictory. Modulation by diet or other lifestyle factors is also not well understood.

Objective

To investigate whether MC4R and FTO associations with body-weight are modulated by diet and physical activity (PA), and to study their association with alcohol and food intake.

Methods

Adherence to Mediterranean diet (AdMedDiet) and physical activity (PA) were assessed by validated questionnaires in 7,052 high cardiovascular risk subjects. MC4R rs17782313 and FTO rs9939609 were determined. Independent and joint associations (aggregate genetic score) as well as statistical and biological gene-lifestyle interactions were analyzed.

Results

FTO rs9939609 was associated with higher body mass index (BMI), waist circumference (WC) and obesity (P<0.05 for all). A similar, but not significant trend was found for MC4R rs17782313. Their additive effects (aggregate score) were significant and we observed a 7% per-allele increase of being obese (OR = 1.07; 95%CI 1.01–1.13). We found relevant statistical interactions (P<0.05) with PA. So, in active individuals, the associations with higher BMI, WC or obesity were not detected. A biological (non-statistical) interaction between AdMedDiet and rs9939609 and the aggregate score was found. Greater AdMedDiet in individuals carrying 4 or 3-risk alleles counterbalanced their genetic predisposition, exhibiting similar BMI (P = 0.502) than individuals with no risk alleles and lower AdMedDiet. They also had lower BMI (P = 0.021) than their counterparts with low AdMedDiet. We did not find any consistent association with energy or macronutrients, but found a novel association between these polymorphisms and lower alcohol consumption in variant-allele carriers (B+/−SE: −0.57+/−0.16 g/d per-score-allele; P = 0.001).

Conclusion

Statistical and biological interactions with PA and diet modulate the effects of FTO and MC4R polymorphisms on obesity. The novel association with alcohol consumption seems independent of their effects on BMI.     

Accelerated telomere attrition is associated with relative household income, diet and inflammation in the pSoBid cohort

Background

It has previously been hypothesized that lower socio-economic status can accelerate biological ageing, and predispose to early onset of disease. This study investigated the association of socio-economic and lifestyle factors, as well as traditional and novel risk factors, with biological-ageing, as measured by telomere length, in a Glasgow based cohort that included individuals with extreme socio-economic differences.

Methods

A total of 382 blood samples from the pSoBid study were available for telomere analysis. For each participant, data was available for socio-economic status factors, biochemical parameters and dietary intake. Statistical analyses were undertaken to investigate the association between telomere lengths and these aforementioned parameters.

Results

The rate of age-related telomere attrition was significantly associated with low relative income, housing tenure and poor diet. Notably, telomere length was positively associated with LDL and total cholesterol levels, but inversely correlated to circulating IL-6.

Conclusions

These data suggest lower socio-economic status and poor diet are relevant to accelerated biological ageing. They also suggest potential associations between elevated circulating IL-6, a measure known to predict cardiovascular disease and diabetes with biological ageing. These observations require further study to tease out potential mechanistic links.     

Diet and cell size both affect queen-worker differentiation through DNA methylation in honey bees (Apis mellifera, Apidae)

Background

Young larvae of the honey bee (Apis mellifera) are totipotent; they can become either queens (reproductives) or workers (largely sterile helpers). DNA methylation has been shown to play an important role in this differentiation. In this study, we examine the contributions of diet and cell size to caste differentiation.

Methodology/Principal Findings

We measured the activity and gene expression of one key enzyme involved in methylation, Dnmt3; the rates of methylation in the gene dynactin p62; as well as morphological characteristics of adult bees developed either from larvae fed with worker jelly or royal jelly; and larvae raised in either queen or worker cells. We show that both diet type and cell size contributed to the queen-worker differentiation, and that the two factors affected different methylation sites inside the same gene dynactin p62.

Conclusions/Significance

We confirm previous findings that Dnmt3 plays a critical role in honey bee caste differentiation. Further, we show for the first time that cell size also plays a role in influencing larval development when diet is kept the same.     

Prognostic and predictive significance of p53, EGFr,Ki-67 in larynx preservation treatment

Background

The optimal management of advanced laryngeal and hypopharyngeal cancers (L&HC) must involve consideration of both survival and functional effect of the given treatment approach. Despite over two decades of investigations of several treatment options, including surgery, radiotherapy, chemotherapy or some combinations thereof, little consensus exists as to which treatment offers the best survival, together with functional speech and swallowing.

Aim

To determine predictive and prognostic value of p53, EGFr, Ki-67 in patients with advanced laryngeal and hypopharyngeal cancer, treated with larynx preservation intent.

Materials and methods

Thirty-three patients received 2–3 cycles of induction chemotherapy (ICHT) consisting of cisplatin and fluoruracil and underwent subsequent radical radiotherapy. Immunohistochemical analyzes of p53, EGFr and Ki-67 were performed.

Results

Response to ICHT was obtained in 24 patients (75%). Better response to ICHT was correlated only with EGFr expression (p = 0.04, RR = 1.91). The 5-year loco-regional control (LRC) and disease-specific survival (DSS) rates were 48% and 57%, respectively. The 5-year larynx preservation rate was 68% in responders to ICHT compared to 21% in non-responders (p = 0.02). It was also higher in patients without EGFr expression (but not significantly, p = 0.43).

Conclusion

Lack of EGFr expression is a favorable predictive factor for response to ICHT. Neither p53 nor Ki-67 have predictive and prognostic value in larynx preservation treatment.     

Cuticular compounds bring new insight in the post-glacial recolonization of a Pyrenean area: Deutonura deficiens Deharveng, 1979 complex, a case study

Background

In most Arthropod groups, the study of systematics and evolution rely mostly on neutral characters, in this context cuticular compounds, as non-neutral characters, represent an underexplored but potentially informative type of characters at the infraspecific level as they have been routinely proven to be involved in sexual attraction.

Methods and Findings

The collembolan species complex Deutonura deficiens was chosen as a model in order to test the utility of these characters for delineating four infraspecific entities of this group. Specimens were collected for three subspecies (D. d. deficiens, D. d. meridionalis, D. d. sylvatica) and two morphotypes (D. d. sylvatica morphoype A and B) of the complex; an additional species D. monticola was added. Cuticular compounds were extracted and separated by gas chromatography for each individual. Our results demonstrate that cuticular compounds succeeded in separating the different elements of this complex. Those data allowed also the reconstruction of the phylogenetic relationships among them.

Conclusions

The discriminating power of cuticular compounds is directly related to their involvement in sexual attraction and mate recognition. These findings allowed a discussion on the potential involvement of intrinsic and paleoclimatic factors in the origin and the diversification of this complex in the Pyrenean zone. This character type brings the first advance from pattern to process concerning the origin of this species complex.     

Molecular phylogeny and biogeography of the fern genus Pteris (Pteridaceae)

Background and Aims

Pteris (Pteridaceae), comprising over 250 species, had been thought to be a monophyletic genus until the three monotypic genera Neurocallis, Ochropteris and Platyzoma were included. However, the relationships between the type species of the genus Pteris, P. longifolia, and other species are still unknown. Furthermore, several infrageneric morphological classifications have been proposed, but are debated. To date, no worldwide phylogenetic hypothesis has been proposed for the genus, and no comprehensive biogeographical history of Pteris, crucial to understanding its cosmopolitan distribution, has been presented.

Methods

A molecular phylogeny of Pteris is presented for 135 species, based on cpDNA rbcL and matK and using maximum parsimony, maximum likelihood and Bayesian inference approaches. The inferred phylogeny was used to assess the biogeographical history of Pteris and to reconstruct the evolution of one ecological and four morphological characters commonly used for infrageneric classifications.

Key Results

The monophyly of Pteris remains uncertain, especially regarding the relationship of Pteris with Actiniopteris + Onychium and Platyzoma. Pteris comprises 11 clades supported by combinations of ecological and morphological character states, but none of the characters used in previous classifications were found to be exclusive synapomorphies. The results indicate that Pteris diversified around 47 million years ago, and when species colonized new geographical areas they generated new lineages, which are associated with morphological character transitions.

Conclusions

This first phylogeny of Pteris on a global scale and including more than half of the diversity of the genus should contribute to a new, more reliable infrageneric classification of Pteris, based not only on a few morphological characters but also on ecological traits and geographical distribution. The inferred biogeographical history highlights long-distance dispersal as a major process shaping the worldwide distribution of the species. Colonization of different niches was followed by subsequent morphological diversification. Dispersal events followed by allopatric and parapatric speciation contribute to the species diversity of Pteris.     

On the roles of colour and scent in a specialized floral mimicry system

Background and Aims

Sexually deceptive orchids achieve cross-pollination by mimicking the mating signals of female insects, generally hymenopterans. This pollination mechanism is often highly specific as it is based primarily on the mimicry of mating signals, especially the female sex pheromones of the targeted pollinator. Like many deceptive orchids, the Mediterranean species Ophrys arachnitiformis shows high levels of floral trait variation, especially in the colour of the perianth, which is either green or white/pinkinsh within populations. The adaptive significance of perianth colour polymorphism and its influence on pollinator visitation rates in sexually deceptive orchids remain obscure.

Methods

The relative importance of floral scent versus perianth colour in pollinator attraction in this orchid pollinator mimicry system was evaluated by performing floral scent analyses by gas chromatography-mass spectrometry (GC-MS) and behavioural bioassays with the pollinators under natural conditions were performed.

Key Results

The relative and absolute amounts of behaviourally active compounds are identical in the two colour morphs of O. arachnitiformis. Neither presence/absence nor the colour of the perianth (green versus white) influence attractiveness of the flowers to Colletes cunicularius males, the main pollinator of O. arachnitiformis.

Conclusion

Chemical signals alone can mediate the interactions in highly specialized mimicry systems. Floral colour polymorphism in O. arachnitiformis is not subjected to selection imposed by C. cunicularius males, and an interplay between different non-adaptive processes may be responsible for the maintenance of floral colour polymorphism both within and among populations.     

Food Access and Diet Quality Are Associated with Quality of Life Outcomes among HIV-Infected Individuals in Uganda

Background

Food insecurity is associated with poor nutritional and clinical outcomes among people living with HIV/AIDS. Few studies investigate the link between food insecurity, dietary diversity and health-related quality of life among people living with HIV/AIDS.

Objective

We investigated whether household food access and individual dietary diversity are associated with health-related quality of life among people living with HIV/AIDS in Uganda.

Methods

We surveyed 902 people living with HIV/AIDS and their households from two clinics in Northern Uganda. Health-related quality of life outcomes were assessed using the Medical Outcomes Study (MOS)-HIV Survey. We performed multivariate regressions to investigate the relationship between health-related quality of life, household food insecurity and individual dietary diversity.

Results

People living with HIV/AIDS from severe food insecurity households have mean mental health status scores that are 1.7 points lower (p<.001) and physical health status scores that are 1.5 points lower (p<.01). Individuals with high dietary diversity have mean mental health status scores that were 3.6 points higher (p<.001) and physical health status scores that were 2.8 points higher (p<.05).

Conclusions

Food access and diet quality are associated with health-related quality of life and may be considered as part of comprehensive interventions designed to mitigate psychosocial consequences of HIV.     

Interspecific gene flow in a multispecies oak hybrid zone in the Sierra Tarahumara of Mexico

Background and Aims

Interspecific gene flow can occur in many combinations among species within the genus Quercus, but simultaneous hybridization among more than two species has been rarely analysed. The present study addresses the genetic structure and morphological variation in a triple hybrid zone formed by Q. hypoleucoides, Q. scytophylla and Q. sideroxyla in north-western Mexico.

Methods

A total of 247 trees from ten reference and 13 presumed intermediate populations were characterized using leaf shape variation and geometric morphometrics, and seven nuclear microsatellites as genetic markers. Discriminant function analysis was performed for leaf shape variation, and estimates of genetic diversity and structure, and individual Bayesian genetic assignments were obtained.

Key Results

Reference populations formed three completely distinct groups according to discriminant function analysis based on the morphological data, and showed low, but significant, genetic differentiation. Populations from the zone of contact contained individuals morphologically intermediate between pairs of species in different combinations, or even among the three species. The Bayesian admixture analysis found that three main genetic clusters best fitted the data, with good correspondence of reference populations of each species to one of the genetic clusters, but various degrees of admixture evidenced in populations from the contact area.

Conclusions

The three oak species have formed a complex hybrid zone that is geographically structured as a mosaic, and comprising a wide range of genotypes, including hybrids between different species pairs, backcrosses and probable triple hybrids.     

Interaction between Maternal and Offspring Diet to Impair Vascular Function and Oxidative Balance in High Fat Fed Male Mice

Aims

To determine the impact of maternal and post-weaning consumption of a high fat diet on endothelium-dependent vasorelaxation and redox regulation in adult male mouse offspring.

Methods

Female C57BL6J mice were fed an obesogenic high fat diet (HF, 45% kcal fat) or standard chow (C, 21% kcal fat) pre-conception and throughout pregnancy and lactation. Post-weaning, male offspring were continued on the same diet as their mothers or placed on the alternative diet to give 4 dietary groups (C/C, HF/C, C/HF and HF/HF) which were studied at 15 or 30 weeks of age.

Results

There were significant effects of maternal diet on offspring body weight (p<0.004), systolic blood pressure (p = 0.026) and endothelium-dependent relaxation to ACh (p = 0.004) and NO production (p = 0.005) measured in the femoral artery. With control for maternal diet there was also an effect of offspring post-weaning dietary fat to increase systolic blood pressure (p<0.0001) and reduce endothelium-dependent relaxation (p = 0.022) and ACh-mediated NO production (p = 0.007). There was also a significant impact of age (p<0.005). Redox balance was perturbed, with altered regulation of vascular enzymes involved in ROS/NO signalling.

Conclusions

Maternal consumption of a HF diet is associated with changes in vascular function and oxidative balance in the offspring of similar magnitude to those seen with consumption of a high fat diet post-weaning. Further, this disadvantageous vascular phenotype is exacerbated by age to influence the risk of developing obesity, raised blood pressure and endothelial dysfunction in adult life.     

Satellite telemetry and long-range bat movements

Background

Understanding the long-distance movement of bats has direct relevance to studies of population dynamics, ecology, disease emergence, and conservation.

Methodology/Principal Findings

We developed and trialed several collar and platform terminal transmitter (PTT) combinations on both free-living and captive fruit bats (Family Pteropodidae: Genus Pteropus). We examined transmitter weight, size, profile and comfort as key determinants of maximized transmitter activity. We then tested the importance of bat-related variables (species size/weight, roosting habitat and behavior) and environmental variables (day-length, rainfall pattern) in determining optimal collar/PTT configuration. We compared battery- and solar-powered PTT performance in various field situations, and found the latter more successful in maintaining voltage on species that roosted higher in the tree canopy, and at lower density, than those that roost more densely and lower in trees. Finally, we trialed transmitter accuracy, and found that actual distance errors and Argos location class error estimates were in broad agreement.

Conclusions/Significance

We conclude that no single collar or transmitter design is optimal for all bat species, and that species size/weight, species ecology and study objectives are key design considerations. Our study provides a strategy for collar and platform choice that will be applicable to a larger number of bat species as transmitter size and weight continue to decrease in the future.