Utilization of biomolecules as fuel energy and their physiological mechanism during migration in birds- A review

Migratory birds undergo physiological and behavioral changes to fuel their high energy demanding migratory flights. They increase their food intake as a part of the preparation for migration which results in increase in their body mass. Fat, carbohydrate and protein acquired from food are stored mainly in the adipose tissue (triglycerides), muscle and liver (glycogen) and body organs (protein) in migratory birds. These stored foods act as fuels to support birds’ migratory flights. Dietary carbohydrates and lipids not only provide energy for migration but also help in fattening as carbohydrates can be converted into fat and lipids which can be stored. Lipolysis of adipose-stored fats leads to the production of triglycerides, fatty acids and glycerol, which provide energy for migration. Fats are depleted after long migratory flights and replenished during refueling at the stopover sites. Being chemically reduced and hydrophobic in nature, fat releases more energy on oxidation as compared to carbohydrate and protein. Due to its high energy-yielding nature, the fat is the preferred fuel to support migration in birds. Migratory birds deposit fat and deplete it during the course of migration. Though, the stored fat acts as the primary source of energy, metabolism of body protein also provides energy for migratory flights. Uric acid in plasma is elevated when protein is catabolized. The metabolism of carbohydrate, stored as glycogen in liver and muscle in migratory birds, produces glucose which also fuels migration. Glucose in migratory birds is maintained at stable levels in plasma and it provides energy only for a flight of short period. Further, catabolism of carbohydrate and protein results in release of metabolic water which helps the migratory birds to maintain their water balance during long dehydrating flight conditions. Different levels of plasma metabolites in migratory birds act as significant indicators of their physiological and metabolic state. Plasma metabolites also give an idea of feeding, fasting and refueling during migration in birds. The available information is scanty and fragmented about how birds meet their migratory requirements and overcome the physiological challenges encountered during migration. The present review article, therefore, focuses on the biomolecules and their plasma biochemistry during migration in birds.

A Sensor-Based Perspective in Early-Stage Parkinson’s Disease: Current State and the Need for Machine Learning Processes

Parkinson’s disease (PD) is a progressive neurodegenerative disorder associated with dysfunction of dopaminergic neurons in the brain, lack of dopamine and the formation of abnormal Lewy body protein particles. PD is an idiopathic disease of the nervous system, characterized by motor and nonmotor manifestations without a discrete onset of symptoms until a substantial loss of neurons has already occurred, enabling early diagnosis very challenging. Sensor-based platforms have gained much attention in clinical practice screening various biological signals simultaneously and allowing researchers to quickly receive a huge number of biomarkers for diagnostic and prognostic purposes. The integration of machine learning into medical systems provides the potential for optimization of data collection, disease prediction through classification of symptoms and can strongly support data-driven clinical decisions. This work attempts to examine some of the facts and current situation of sensor-based approaches in PD diagnosis and discusses ensemble techniques using sensor-based data for developing machine learning models for personalized risk prediction. Additionally, a biosensing platform combined with clinical data processing and appropriate software is proposed in order to implement a complete diagnostic system for PD monitoring.

Effects of sequential feeding with adjustments to dietary amino acid concentration according to the circadian rhythm on the performance, body composition, and nutrient balance of growing-finishing pigs

This study aimed to evaluate the effects of a sequential feeding program (SEQ) with diets varying in amino acid (AA) concentrations in the first and last 12 h of the day on the performance, body composition, and nutrient balance of growing-finishing pigs. Sixty-eight castrated male pigs were distributed in four treatments: a daily feeding program (DP) and three SEQs. In the DP, dietary requirements of AA were adjusted daily. In the SEQ, dietary daily requirements of AA were adjusted every 12 h, providing a low AA concentration in period 1 (P1; 00:00–11:59 h) and a high AA concentration in period 2 (P2; 12:00–23:59 h). In the SEQ, three different levels of low and high AA concentrations were evaluated: ±20%, ±30%, and ±40%. The experiment lasted 82 days and was divided into phase 1 (25–50 kg body weight; BW), phase 2 (50–70 kg BW), and phase 3 (70–100 kg BW). During phase 1, irrespective of dietary AA concentration, SEQ pigs had higher lysine intake, protein gain, and phosphorus efficiency than DP pigs (P ≤ 0.05). Pigs in the SEQ showed a tendency for greater average daily gain, body protein, and body lipids compared to the DP pigs (P ≤ 0.10). During phase 2, SEQ pigs showed a tendency for higher average feed intake in P2 compared to DP pigs (P = 0.07); consequently, average daily gain, body protein, and phosphorus retention tended to increase (P ≤ 0.10). During phase 3, SEQ pigs had a higher average feed intake in P2 than DP pigs (P = 0.03). However, they had a similar body composition (P > 0.05) and a tendency for higher nitrogen excretion (P = 0.06) than DP pigs. Our results suggest that SEQ is an effective approach for improving the performance and body composition of growing pigs.

Skeletal muscle mitochondrial dysfunction and muscle and whole-body functional deficits in cancer patients with weight loss

Reductions in skeletal muscle mass and function are often reported in patients with cancer-associated weight loss and are associated with reduced quality of life, impaired treatment tolerance, and increased mortality. Although cellular changes, including altered mitochondrial function, have been reported in animals, such changes have been incompletely characterized in humans with cancer. Whole body and skeletal muscle physical function, skeletal muscle mitochondrial function and whole-body protein turnover were assessed in 8 patients with cancer-associated weight loss (10.1±4.2% body weight over 6-12 months) and 19 age-, sex-, and BMI-matched healthy controls to characterize skeletal muscle changes at the whole body, muscle, and cellular level. Potential pathways involved in cancer-induced alterations in metabolism and mitochondrial function were explored by interrogating skeletal muscle and plasma metabolomes. Despite similar lean mass compared to control participants, patients with cancer exhibited reduced habitual physical activity (57% fewer daily steps), cardiorespiratory fitness (22% lower VO2peak [mL/kg/min]) and leg strength (35% lower isokinetic knee extensor strength) and greater leg neuromuscular fatigue (36% greater decline in knee extensor torque). Concomitant with these functional declines, patients with cancer had lower mitochondrial oxidative capacity (25% lower State 3 O2 flux [pmol/s/mg tissue]) and ATP production (23% lower State 3 ATP production [pmol/s/mg tissue]) and alterations in phospholipid metabolite profiles indicative of mitochondrial abnormalities. Whole body protein turnover was unchanged. These findings demonstrate mitochondrial abnormalities concomitant with whole-body and skeletal muscle functional derangements associated with human cancer, supporting future work studying the role of mitochondria in the muscle deficits associated with cancer.

Sugar-rich larval diet promotes lower adult pathogen load and higher survival after infection in a polyphagous fly

Nutrition is a central factor influencing immunity and resistance to infection, but the extent to which nutrition during development affects adult responses to infections is poorly understood. Our study investigated how the nutritional composition of the larval diet affects the survival, pathogen load, and food intake of adult fruit flies, Bactrocera tryoni, after bacterial septic infection. We found a sex-specific effect of larval diet composition on survival post-infection: survival rate was higher and bacterial load was lower for infected females fed sugar-rich larval diet compared with females fed protein-rich larval diet, an effect that was absent in males. Both males and females were heavier when fed a balanced larval diet compared to protein- or sugar-rich diet, while body lipid reserves were higher in the sugar-rich larval diet compared with other diets. Body protein reserve was lower for sugar-rich larval diets compared to other diets in males, but not females. Both females and males shifted their nutrient intake to ingest a sugar-rich diet when infected compared with sham-infected flies without any effect of the larval diet, suggesting that sugar-rich diets can be beneficial to fight off bacterial infection. Overall, our findings show that nutrition during early life can shape individual fitness in adulthood.

Applications of DNA-Functionalized Proteins

As an important component that constitutes all the cells and tissues of the human body, protein is involved in most of the biological processes. Inspired by natural protein systems, considerable efforts covering many discipline fields were made to design artificial protein assemblies and put them into application in recent decades. The rapid development of structural DNA nanotechnology offers significant means for protein assemblies and promotes their application. Owing to the programmability, addressability and accurate recognition ability of DNA, many protein assemblies with unprecedented structures and improved functions have been successfully fabricated, consequently creating many brand-new researching fields. In this review, we briefly introduced the DNA-based protein assemblies, and highlighted the limitations in application process and corresponding strategies in four aspects, including biological catalysis, protein detection, biomedicine treatment and other applications.

A Combined Spectroscopic and In Silico Approach to Evaluate the Interaction of Human Frataxin with Mitochondrial Superoxide Dismutase

Frataxin (FXN) is a highly conserved mitochondrial protein whose deficiency causes Friedreich’s ataxia, a neurodegenerative disease. The precise physiological function of FXN is still unclear; however, there is experimental evidence that the protein is involved in biosynthetic iron–sulfur cluster machinery, redox imbalance, and iron homeostasis. FXN is synthesized in the cytosol and imported into the mitochondria, where it is proteolytically cleaved to the mature form. Its involvement in the redox imbalance suggests that FXN could interact with mitochondrial superoxide dismutase (SOD2), a key enzyme in antioxidant cellular defense. In this work, we use site-directed spin labelling coupled to electron paramagnetic resonance spectroscopy (SDSL-EPR) and fluorescence quenching experiments to investigate the interaction between human FXN and SOD2 in vitro. Spectroscopic data are combined with rigid body protein–protein docking to assess the potential structure of the FXN-SOD2 complex, which leaves the metal binding region of FXN accessible to the solvent. We provide evidence that human FXN interacts with human SOD2 in vitro and that the complex is in fast exchange. This interaction could be relevant during the assembly of iron-sulfur (FeS) clusters and/or their incorporation in proteins when FeS clusters are potentially susceptible to attacks by reactive oxygen species.

Pea Proteins Have Anabolic Effects Comparable to Milk Proteins on Whole Body Protein Retention and Muscle Protein Metabolism in Old Rats

Plant proteins are attracting rising interest due to their pro-health benefits and environmental sustainability. However, little is known about the nutritional value of pea proteins when consumed by older people. Herein, we evaluated the digestibility and nutritional efficiency of pea proteins compared to casein and whey proteins in old rats. Thirty 20-month-old male Wistar rats were assigned to an isoproteic and isocaloric diet containing either casein (CAS), soluble milk protein (WHEY) or Pisane™ pea protein isolate for 16 weeks. The three proteins had a similar effect on nitrogen balance, true digestibility and net protein utilization in old rats, which means that different protein sources did not alter body composition, tissue weight, skeletal muscle protein synthesis or degradation. Muscle mitochondrial activity, inflammation status and insulin resistance were similar between the three groups. In conclusion, old rats used pea protein with the same efficiency as casein or whey proteins, due to its high digestibility and amino acid composition. Using these plant-based proteins could help older people diversify their protein sources and more easily achieve nutritional intake recommendations.

Growth and Body Composition of Artificially-Reared Lambs Exposed to Three Different Rearing Regimens

This study was designed to investigate the influence of pellet fibre level, milk replacer composition and age at weaning on growth and body composition of lambs reared artificially. Romney ram lambs were randomly allocated to one of three rearing treatments; HFP57: commercial milk replacer to 57 days of age, and high fibre concentrate pellets; HFP42: commercial milk replacer with early weaning at 42 days of age, and high fibre concentrate pellets; LFP42: high protein milk replacer from 2–16 days of age followed by commercial milk replacer with early weaning at 42 days of age, and low fibre concentrate pellets. Lambs were slaughtered at 57 days of age. Overall average daily liveweight gain of lambs did not differ (p > 0.05) between treatments. Dressing out percentage, carcass weight, empty small intestine and omental fat were higher (p < 0.05) in HFP57 than in both HFP42 and LFP42 lambs. HFP42 and LFP42 lambs had heavier (p < 0.05) empty rumen weights. Whole body protein content was higher (p < 0.05) in HFP42 lambs compared to both HFP57 and LFP42 lambs. Fat content and daily fat deposition were greater (p < 0.05) in HFP57 lambs than HFP42 and LFP42 lambs. Weaning lambs at 42 days of age with provision of either low or high fibre concentrate pellets, resulted in similar growth rates, reduced whole body fat deposition and was a more cost-effective rearing regimen.