Enzyme Teaching by a Virtual Laboratory

Biochemistry learning demands skills to obtaining and interpreting the experimental data. In a classical model of teaching involve student’s hands-on participation. However this model is expensive, not safe and should be carried out in a short and limited time course. With utilization of educational software these disadvantages are overcome, since the virtual activity could be realized at free full access, and is a tool for individual study. The aim of the present work is to present educational software focused on a virtual for undergraduate student of biochemistry courses. The software development was performed with the help of concept maps, ISIS Draw, ADOBE Photoshop and FLASH MX Program applied on the subject salivary amylase. It was possible to present the basic methodologies for study of the kinetic of enzyme. The substrate (starch) consumption was determinate by iodine reaction, while the products (reducing sugars) formation was evaluated by cupper-alkaline reaction. The protocols of the virtual experiments are present verbally as well as a subtitle. A set of exercises are disposable, which allowed an auto evaluation and a review of the subject. The experimental treatment involved the presentation of this hypermedia for Nutrition and Dentistry/UFSC undergraduate students as a tool for better comprehension of the theme and promoted the understanding of the kinetic of enzyme

Biochemical Hypermedia: Galactose Metabolism.

Introduction: Animations of biochemical processes and virtual laboratory environments lead to true molecular simulations. The use of interactive software’s in education can improve cognitive capacity, better learning and, mainly, it makes information acquisition easier. Material and Methods: This work presents the development of a biochemical hypermedia to understanding of the galactose metabolism. It was developed with the help of concept maps, ISIS Draw, ADOBE Photoshop and FLASH MX Program. Results and Discussion: A step by step animation process shows the enzymatic reactions of galactose conversion to glucose-1-phosphate (to glycogen synthesis), glucose-6-phosphate (glycolysis intermediary), UDP-galactose (substrate to mucopolysaccharides synthesis and collagen’s glycosylation). There are navigation guide that allow scrolling the mouse over the names of the components of enzymatic reactions of via the metabolism of galactose. Thus, explanatory text box, chemical structures and animation of the actions of enzymes appear to navigator. Upon completion of the module, the user’s response to the proposed exercise can be checked immediately through text box with interactive content of the answer. Conclusion: This hypermedia was presented for undergraduate students (UFSC) who revealed that it was extremely effective in promoting the understanding of the theme

Virtual Biochemistry – pH effect on enzyme activity

Protocols of laboratory experiments, followed by teacher's explanation, not always clearly translate to the student the dynamics to beadopted for the implementation of the proposed practice. One of these cases is related to the study of the effect of pH on enzyme activity. For better help the understanding of the technical procedure, a hypermedia was built based on a protocol adopted at the Department of Biochemistry, UFSC. The hypermedia shows how theeffect of variations in pH can be observed  in vitro. Taking as example salivary amylase and the consumption of starch (substrate) by means of iodine staining, a set of pH buffers was tested to identify the best pH for this enzyme  activity. This hypermedia as introductory tool for such practice was tested on aNutrition course classroom. Students agree that the hypermedia provided a better understanding of the proposed activities. Teachers also notice a smallerreagents consumption and reduction of the time spent by the students in the achievement of the experiment

Biochemical software: Carbohydrates on Laboratory

Educators around  the  world  are  being  challenged  to  develop  and  design  better and  more  effective strategies for student learning  using a variety  of modern  resources.  In this  present  work, an educa- tional  hypermedia  software  was constructed as a support tool to biochemistry teaching.  Occurrence, structure, main  characteristics and  biological  function  of the  biomolecule  Carbohydrates were pre- sented  through  modules.  The  software was developed  using concept  maps,  ISIS-Draw,  and  FLASH- MX animation program.  The chapter  Carbohydrates on Laboratory illustrates experimental methods of carbohydrates characterization, through  animation of a laboratory scenery.   The  subject was de- veloped showing reactions  as Bial, Benedict, Selliwanoff, Barfoed, Phenol  Sulphuric,  and Iodines, and also enzymatic  reactions  as glucose oxidase and amylase.  There are also links with short texts  in order to help the understanding of the contents  and principles of laboratory practice  as well as background reactions. Application of the software to undergraduate students and high school teachers  showed an excellent  acceptance.   All of them  considered  the  software  a very good learning  tool.  Both  teachers and students welcomed this program  as it is more flexible, and allows the learning in a more individual rhythm. In addition, application of the software would be suitable  to a more effective learning  and it is less expensive than conventional experimental teaching

A Comparative Study of Cellulase and Xylanase Activity in Freshwater Crayfish and Marine Prawns

Cellulase and xylanase digestive enzyme activities were compared in four freshwater crayfish (Genus Cherax) and three marine prawn (Genus Penaeus) species.Temperature and pH profiles for cellulase (endoglucanase)were found to be very similar in all species, with maximum activity occurring at 60oC and pH 5.0.Temperature and pH profiles for xylanase (endoxylanase)were also very similar in all cray¢sh species,with maximum activity occurring at 50oC and pH 5.0. Xylanase activity was not detected in the three prawn species examined. In addition, in vitro studies showed thatmost species were able to liberate glucose from carboxymethyl cellulose, indicating that cellulose substrates can be a source of energy for both crayfish and prawn species

Influence of Insoluble Dietary Cellulose on Digestive Enzyme Activity, Feed Digestibility and Survival in the Red Claw Crayfish, Cherax quadricarinatus (von Martens)

Red claw (Cherax quadricarinatus) is a freshwater crayish species with recognized potential for aquaculture. To better understand the digestive processes and nutritional requirements of red claw, we have examined the effects of dietary cellulose on (1) digestive enzyme activity and diet digestibility and (2) survival rate, feed conversion ratio and growth performance. In the first study, a reference diet (RF) and test diets consisting of 70% RF and 30% a-cellulose or Fuller’s earth were prepared. Analysis of digestive enzyme profiles revealed that amylase and cellulase activities in midgut gland (MG) extracts were highest in the red claw fed on a diet containing 30% Fuller's earth and lowest in those fed on a diet containing 30% a-cellulose. Supplementation of the RF diet with either 30% a-cellulose or Fuller’s earth signi¢cantly reduced apparent dry matter ADMD) and apparent protein digestibilities (APD). In the second study, a feeding trial was conducted using diets supplemented with different levels of a-cellulose. A major finding was that dietary cellulose levels above 12% were correlated with signifcant reductions in survival rate, specific growth rate and feeding efficiency. Based on these findings,we suggest that although cellulase enzymes are present in the red claw digestive system there are no apparent nutritive benefits obtained by including insoluble cellulose in diets for this species