RESUMEN

Computational modeling (CM) is a versatile scientific methodology used to examine the properties and behavior of complex systems, such as polymeric materials for biomedical bioengineering. CM has emerged as a primary tool for predicting, setting up, and interpreting experimental results. Integrating in silico and in vitro experiments accelerates scientific advancements, yielding quicker results at a reduced cost. While CM is a mature discipline, its use in biomedical engineering for biopolymer materials has only recently gained prominence. In biopolymer biomedical engineering, CM focuses on three key research areas: (A) Computer-aided design (CAD/CAM) utilizes specialized software to design and model biopolymers for various biomedical applications. This technology allows researchers to create precise three-dimensional models of biopolymers, taking into account their chemical, structural, and functional properties. These models can be used to enhance the structure of biopolymers and improve their effectiveness in specific medical applications. (B) Finite element analysis, a computational technique used to analyze and solve problems in engineering and physics. This approach divides the physical domain into small finite elements with simple geometric shapes. This computational technique enables the study and understanding of the mechanical and structural behavior of biopolymers in biomedical environments. (C) Molecular dynamics (MD) simulations involve using advanced computational techniques to study the behavior of biopolymers at the molecular and atomic levels. These simulations are fundamental for better understanding biological processes at the molecular level. Studying the wide-ranging uses of MD simulations in biopolymers involves examining the structural, functional, and evolutionary aspects of biomolecular systems over time. MD simulations solve Newton's equations of motion for all-atom systems, producing spatial trajectories for each atom. This provides valuable insights into properties such as water absorption on biopolymer surfaces and interactions with solid surfaces, which are crucial for assessing biomaterials. This review provides a comprehensive overview of the various applications of MD simulations in biopolymers. Additionally, it highlights the flexibility, robustness, and synergistic relationship between in silico and experimental techniques.

RESUMEN

It has been reported that phaseolin, the major storage globulin of the common bean (Phaseolus vulgaris), is toxic to Callosobruchus maculatus larvae, an Old World bruchid beetle that is not capable of infesting this New World edible bean. It has also been demonstrated that vicilin, the major storage globulin found in cowpea (Vigna unguiculata) seeds, is absorbed through receptor-mediated endocytosis in the insect midgut. A putative vicilin receptor has been purified and showed high homology to α-tocopherol transfer protein. However, the ingestion of a variant vicilin purified from C. maculatus resistant seeds inhibits transcytosis, resulting in the accumulation of vicilins in the midgut cells and ultimately antibiosis. In the present work, we studied the cellular up-take of phaseolin in C. maculatus larvae with the aim of discovering if this protein is also capable of inhibiting endocytic traffic in the enterocytes. FITC-labelled vicilin and FITC-labelled phaseolin were incorporated into the diet of the larvae at a physiological concentration of 0.5% w/w. The fate of labelled and non-labelled globulins was monitored by confocal microscopy. Here we demonstrated that phaseolin is also endocytosed by enterocytes causing an accumulation of endocytic vesicles in the midgut when compared to the ingestion of vicilin obtained from a susceptible V. unguiculata cultivar. From the results obtained for HNE, MDA and TBARS, a pro-oxidative scenario was established in the intestinal epithelial cells of the larvae, which may explain the deleterious effect observed in larvae developing inside P. vulgaris seeds.

Asunto(s)

RESUMEN

It has been demonstrated that variant vicilins are the main resistance factor of cowpea seeds (Vigna unguiculata) against attack by the cowpea beetle Callosobruchus maculatus. There is evidence that the toxic properties of these storage proteins may be related to their interaction with glycoproteins and other microvillar membrane constituents along the digestive tract of the larvae. New findings have shown that following interaction with the microvilli, the vicilins are absorbed across the intestinal epithelium and thus reach the internal environment of the larvae. In the present paper we studied the insecticidal activity of the variant vicilins purified from a resistant cowpea variety (IT81D-1053). Bioassays showed that the seeds of this genotype affected larval growth, causing developmental retardation and 100% mortality. By feeding C. maculatus larvae on susceptible and IT81D-1053 derived vicilins (FITC labelled or unlabelled), followed by fluorescence and immunogold cytolocalization, we were able to demonstrate that both susceptible and variant forms are internalized in the midgut cells and migrate inside vesicular structures from the apex to the basal portion of the enterocytes. However, when larvae were fed with the labelled vicilins for 24h and then returned to a control diet, the concentration of the variant form remained relatively high, suggesting that variant vicilins are not removed from the cells at the same rate as the non-variant vicilins. We suggest that the toxic effects of variant vicilins on midgut cells involve the binding of these proteins to the cell surface followed by internalization and interference with the normal physiology of the enterocytes, thereby affecting larval development in vivo.

Asunto(s)

RESUMEN

The effect of dietary protein on growth, carcass traits and some specific intestinal intestinal peptide and amino acid transporters in broiler chickens was studied. Birds received a common pre-test diet, and were subsequently fed either a standard positive control diet (PC) or a reduced CP diet (RCP) from 21 to 42 d of age. Growth was negatively impacted with feeding of RCP as manifested by an increase in feed consumption and feed conversion ratio. Carcass traits also showed evidence of negative effects of feeding the RCP diet, leading to a reduction in carcass and breast meat yield and an increase in abdominal fat percentage. Blood plasma total protein was reduced when the broilers were fed the RCP diet. Expression of mRNA for one peptide (PepT1) and four AA intestinal transporters (bo,+AT; CAT2; y+LAT2; EAAT3) was measured from the jejunum. Quantified mRNA for the AA transporters y+LAT2 and EAAT3 showed that they were up-regulated in chickens fed the RCP-diet. The transport systems PepT1, bo,+AT, and CAT2, were not affected by the dietary treatment imposed. The live and processing data validated the in vivo portion of the study and elucidated the negative impact of feeding the RCP diet, while the responses observed with the expression of the various transporters may help provide some insight on the physiological consequences and adaptations that birds endure when provided diets too low in CP for abnormally extended periods of time.

Asunto(s)

RESUMEN

The effect of dietary protein on growth, carcass traits and some specific intestinal intestinal peptide and amino acid transporters in broiler chickens was studied. Birds received a common pre-test diet, and were subsequently fed either a standard positive control diet (PC) or a reduced CP diet (RCP) from 21 to 42 d of age. Growth was negatively impacted with feeding of RCP as manifested by an increase in feed consumption and feed conversion ratio. Carcass traits also showed evidence of negative effects of feeding the RCP diet, leading to a reduction in carcass and breast meat yield and an increase in abdominal fat percentage. Blood plasma total protein was reduced when the broilers were fed the RCP diet. Expression of mRNA for one peptide (PepT1) and four AA intestinal transporters (bo,+AT; CAT2; y+LAT2; EAAT3) was measured from the jejunum. Quantified mRNA for the AA transporters y+LAT2 and EAAT3 showed that they were up-regulated in chickens fed the RCP-diet. The transport systems PepT1, bo,+AT, and CAT2, were not affected by the dietary treatment imposed. The live and processing data validated the in vivo portion of the study and elucidated the negative impact of feeding the RCP diet, while the responses observed with the expression of the various transporters may help provide some insight on the physiological consequences and adaptations that birds endure when provided diets too low in CP for abnormally extended periods of time.(AU)

Asunto(s)