See How I Eat My Greens—Autophagy in Plant Cells

Eukaryotic cells have two conserved pathways for degrading polypeptides. One is the highly selective ubiquitin–proteasome system, and the other is autophagy, a bulk degradation pathway to a lytic compartment. Autophagy in plant cells has important roles in development and responses to abiotic and biotic stresses. Furthermore, plant autophagy has been implicated in vacuole biogenesis and Golgi-independent targeting of cytoplasmic materials to vacuoles. Here I present four questions that are frequently asked by plant scientists interested in autophagy. The first question relating to tools for plant autophagy research is relatively easy to answer, while the others are open questions about regulation of autophagy, autophagic cargoes, and potential differences of plant autophagic routes from corresponding metazoan pathways. This review will discuss recent progress that may provide the answers for the latter questions.     

To Eat or Not To Eat? The Diet of the Endangered Iberian Wolf (Canis lupus signatus) in a Human-Dominated Landscape in Central Portugal

Livestock predation by large carnivores and their persecution by local communities are major conservation concerns. In order to prevent speculations and reduce conflicts, it is crucial to get detailed and accurate data on predators’ dietary ecology, which is particularly important in human dominated landscapes where livestock densities are high. This is the case of the endangered Iberian wolf in Portugal, an endemic subspecies of the Iberian Peninsula, which has seen its population distribution and abundance decline throughout the 20th century. Accordingly, the diet of the Iberian wolf was analyzed, using scat analysis, in a humanized landscape in central Portugal. From 2011 to 2014, a total of 295 wolf scats were collected from transects distributed throughout the study area, prospected on a monthly basis. Scat analysis indicated a high dependence of Iberian wolf on livestock. Domestic goat predominated the diet (62% of the scats), followed by cow (20%) and sheep (13%); the only wild ungulate present in the scat analysis was the wild boar (4% of the scats). Our results show that even though livestock constitute most part of wolves diet, different livestock species may represent different predation opportunities. We conclude that the high levels of livestock consumption may be a result of low diversity and density of wild ungulates that settles livestock as the only abundant prey for wolves. Our findings help on the understanding of the Iberian wolf feeding ecology and have implications for conflict management strategies. Finally, management implications are discussed and solutions are recommended.     

Food, Nutrigenomics, and Neurodegeneration—Neuroprotection by What You Eat!

Diet in human health is no longer simple nutrition, but in light of recent research, especially nutrigenomics, it is linked via evolution and genetics to cell health status capable of modulating apoptosis, detoxification, and appropriate gene response. Nutritional deficiency and disease especially lack of vitamins and minerals is well known, but more recently, epidemiological studies suggest a role of fruits and vegetables, as well as essential fatty acids and even red wine (French paradox), in protection against disease. In the early 1990s, various research groups started considering the use of antioxidants (e.g., melatonin, resveratrol, green tea, lipoic acid) and metabolic compounds (e.g., nicotinamide, acetyl-l-carnitine, creatine, coenzyme Q₁₀) as possible candidates in neuroprotection. They were of course considered on par with snake oil salesman (women) at the time. The positive actions of nutritional supplements, minerals, and plant extracts in disease prevention are now mainstream and commercial health claims being made are subject to regulation in most countries. Apart from efficacy and finding, the right dosages, the safety, and especially the level of purification and lack of contamination are all issues that are important as their use becomes widespread. From the mechanistic point of view, most of the time these substances replenish the body’s deficiency and restore normal function. However, they also exert actions that are not sensu stricto nutritive and could be considered pharmacological especially that, at times, higher intake than recommended (RDA) is needed to see these effects. Free radicals and neuroinflammation processes underlie many neurodegenerative conditions, even Parkinson’s disease and Alzheimer’s disease. Curcumin, carotenoids, acetyl-l-carnitine, coenzyme Q₁₀, vitamin D, and polyphenols and other nutraceuticals have the potential to target multiple pathways in these conditions. In summary, augmenting neuroprotective pathways using diet and finding new natural substances that can be more efficacious, i.e., induction of health-promoting genes and reduction of the expression of disease-promoting genes, could be incorporated into neuroprotective strategies of the future.     

Eat now,pay later? Evidence of deferred food-processing costs in diving seals

Seals may delay costly physiological processes (e.g. digestion) that are incompatible with the physiological adjustments to diving until after periods of active foraging. We present unusual profiles of metabolic rate (MR) in grey seals measured during long-term simulation of foraging trips (4-5 days) that provide evidence for this. We measured extremely high MRs (up to almost seven times the baseline levels) and high heart rates during extended surface intervals, where the seals were motionless at the surface. These occurred most often during the night and occurred frequently many hours after the end of feeding bouts. The duration and amount of oxygen consumed above baseline levels during these events was correlated with the amount of food eaten, confirming that these metabolic peaks were related to the processing of food eaten during foraging periods earlier in the day. We suggest that these periods of high MR represent a payback of costs deferred during foraging.     

Do Obese Eat Faster Than Lean Subjects? Food Intake Studies in Pima Indian Men

Food intake rate has previously been derived from observation of eating behavior in laboratory settings or in public eating establishments. Although it has been suggested that obese individuals eat faster than lean individuals, observations of such an “obese eating style” have yielded mixed results. In the present study, the relationship between ad-libitum food intake rate and obesity was evaluated over 4 days on a metabolic ward in 28 healthy Pima Indian men (Mean ± SD; 29 ± 7 y, 100.4 ± 27.1 kg, 33 ± 10% body fat) using an automated food selection system containing a large variety of foods . Total energy intake averaged 18829 ± 3299 kJ/d consisting of 47 ± 4,40 ± 3, and 13 ± 1 percent of carbohydrate, fat and protein, respectively. The average meal duration was 25 ± 7 min. Food intake rate was 68 ± 21 g/min while carbohydrate, fat and protein intake rates were 23 ± 6, 9 ± 3 and 6 ± 2 g/min, respectively. Food intake rate correlated negatively with %body fat (1=0.61, P<0.01). Similar relationships were found between the intake rates of carbohydrate, fat and protein and body fatness. Only prospective studies will indicate whether a slow food intake rate may contribute to the etiology of obesity by possibly reducing satiety .     

Why Does the Giant Panda Eat Bamboo? A Comparative Analysis of Appetite-Reward-Related Genes among Mammals

Background

The giant panda has an interesting bamboo diet unlike the other species in the order of Carnivora. The umami taste receptor gene T1R1 has been identified as a pseudogene during its genome sequencing project and confirmed using a different giant panda sample. The estimated mutation time for this gene is about 4.2 Myr. Such mutation coincided with the giant panda''s dietary change and also reinforced its herbivorous life style. However, as this gene is preserved in herbivores such as cow and horse, we need to look for other reasons behind the giant panda''s diet switch.

Methodology/Principal Findings

Since taste is part of the reward properties of food related to its energy and nutrition contents, we did a systematic analysis on those genes involved in the appetite-reward system for the giant panda. We extracted the giant panda sequence information for those genes and compared with the human sequence first and then with seven other species including chimpanzee, mouse, rat, dog, cat, horse, and cow. Orthologs in panda were further analyzed based on the coding region, Kozak consensus sequence, and potential microRNA binding of those genes.

Conclusions/Significance

Our results revealed an interesting dopamine metabolic involvement in the panda''s food choice. This finding suggests a new direction for molecular evolution studies behind the panda''s dietary switch.     

Eat and run? The hunger/satiation hypothesis in vertical migration: history,evidence and consequences

The study of vertical migrations in aquatic organisms has a long and colourful history, much of it to do with the effects of changing sampling technology on our understanding of the phenomenon. However, the overwhelming majority of such studies carried out today still depend on detecting differences in vertical distribution profiles during some course of time, or acoustic echoes of migrating bands of organisms. These can not distinguish migratory activity of individual organisms, but can only assess net results of mass transfers of populations, which may integrate many individual migrations. This is an important distinction, for without knowing the actual movements of individuals it seems unlikely that we will be able to understand their causes, nor the effects of vertical migrations on the environment or on the migrators themselves. This review examines evidence for individual vertical movements gathered from 'tracers', mainly gut contents, and reviews the evidence for the hypothesis that such movements are in fact driven by hunger and satiation. The more recently appreciated vertical migrations of phytoplankters and their similarities in form and driving forces to those of zooplankton and nekton are also discussed. Finally, the role of vertical migrators in vertical fluxes of materials is discussed, along with the consequences of satiation-driven descent for such estimates.     

Phagocytosis and Cytokinesis: Do Cells Use Common Tools to Cut and to Eat? Highlights on Common Themes and Differences

Eukaryotic cells with specialized functions often use and adapt common molecular machineries. Recent findings have highlighted that actin polymerization, contractile activity and membrane remodelling with exocytosis of internal compartments are required both for successful phagocytosis, the internalization of particulate material and for cytokinesis, the last step of cell division. Phagocytosis is induced by the triggering of specific cell surface receptors, which leads to membrane deformation, pseudopod extension and contraction to engulf particles. Cytokinesis relies on intense contractile activity and eventually leads to the physical scission of sister cells. In this review, shared features of signalling, cytoskeletal reorganization and vesicular trafficking used in both phagocytosis and cytokinesis will be described, but non‐common mechanisms and questions that remain open in these dynamic areas of research are also highlighted .      

Is an Idea Different from Cake: Can You Have It and Eat It,Too? A Violation of Permanence in Information Consumption

One of the basic features of information is permanence. This feature states that the consumption of information by one consumer does not affect the availability of that information to other consumers. We present examples in two studies indicating that both laymen and experts of information exchange may be motivated to make choices that violate the permanence feature in accepting (Study 1) and offering (Study 2) information. When they possess, but have not yet consumed information, people may suffer from the appearance of wastefulness. This apparent wastefulness may provide a potential explanation for the observed violation of the permanence feature. Our findings indicate that, as the material age evolves into the information age, information-exchange behavior has not evolved significantly away from material-exchange behavior.     

What Should I Eat and Why? The Environmental,Genetic, and Behavioral Determinants of Food Choice: Summary from a Pennington Scientific Symposium

This review details the proceedings of a Pennington Biomedical scientific symposium titled, “What Should I Eat and Why? The Environmental, Genetic, and Behavioral Determinants of Food Choice.” The symposium was designed to review the literature about energy homeostasis, particularly related to food choice and feeding behaviors, from psychology to physiology. This review discusses the intrinsic determinants of food choice, including biological mechanisms (genetics), peripheral and central signals, brain correlates, and the potential role of the microbiome. This review also address the extrinsic determinants (environment) of food choice within our physical and social environments. Finally, this review reports the current treatment practices for the clinical management of eating‐induced overweight and obesity. An improved understanding of these determinants will inform best practices for the clinical treatment and prevention of obesity. Strategies paired with systemic shifts in our public health policies and changes in our “obesogenic” environment will be most effective at attenuating the obesity epidemic.     

Overweight,Obesity and Underweight Is Associated with Adverse Psychosocial and Physical Health Outcomes among 7-Year-Old Children: The ‘Be Active,Eat Right’ Study

Background

Limited studies have reported on associations between overweight, and physical and psychosocial health outcomes among younger children. This study evaluates associations between overweight, obesity and underweight in 5-year-old children, and parent-reported health outcomes at age 7 years.

Methods

Data were used from the ‘Be active, eat right’ study. Height and weight were measured at 5 and 7 years. Parents reported on child physical and psychosocial health outcomes (e.g. respiratory symptoms, general health, happiness, insecurity and adverse treatment). Regression models, adjusted for potential confounders, were fitted to predict health outcomes at age 7 years.

Results

The baseline study sample consisted of 2,372 children mean age 5.8 (SD 0.4) years; 6.2% overweight, 1.6% obese and 15.0% underweight. Based on parent-report, overweight, obese and underweight children had an odds ratio (OR) of 5.70 (95% CI: 4.10 to 7.92), 35.34 (95% CI: 19.16; 65.17) and 1.39 (95% CI: 1.05 to 1.84), respectively, for being treated adversely compared to normal weight children. Compared to children with a low stable body mass index (BMI), parents of children with a high stable BMI reported their child to have an OR of 3.87 (95% CI: 1.75 to 8.54) for visiting the general practitioner once or more, an OR of 15.94 (95% CI: 10.75 to 23.64) for being treated adversely, and an OR of 16.35 (95% CI: 11.08 to 24.36) for feeling insecure.

Conclusion

This study shows that overweight, obesity and underweight at 5 years of age is associated with more parent-reported adverse treatment of the child. Qualitative research examining underlying mechanisms is recommended. Healthcare providers should be aware of the possible adverse effects of childhood overweight and also relative underweight, and provide parents and children with appropriate counseling.