Bayardo Baptista Torres

Substrate Specificities of Midgut β-Glycosidases from Insects of Different Orders

Abstract β -Glycosidase activity was determined in midgut homogenates and in electrophoretically-resolved midgut samples from the following insects: Orthoptera, Abracris flavolineata; Coleoptera, Pheropsophus aequinoctialis, Tenebrio molitor, Pyrearinus termitilluminans ; Hymenoptera, Scaptotrigona bipunctata ; Diptera, Rhynchosciara americana ; Lepidoptera, Erinniys ello, Spodoptera frugiperda , and Diatraea saccharalis . The substrates used in the assays included disaccharides (cellobiose and lactose), synthetic aryl β -glucosides ( p -nitrophenyl β -glucoside and p -nitrophenyl β -galactoside), and plant glycosides (salicin and amygdalin). Orthopterans, coleopterans, and hymenopterans have in their midgut β -galactosidases (active only on β -galactosides) and class 2 (active only on disaccharides) and class 3 (active only on synthetic and plant glycosides) β -glucosidases. Class 1 (active on disaccharides and on synthetic and plant glycosides) β -glucosidases, at least in orthopterans, have putatively different sites for each activity. Dipterans have β -galactosidases and a single class 1 β -glucosidase. Lepidopterans have no β -galactosidases and may have a single class 1 β -glucosidase or class 1 and class 3 β -glucosidases. There seems to be an evolutionary trend from multiple enzymes with different substrate specificities to a single enzyme able to hydrolyse all the β -glycosides in the same site.

A quick guide for computer-assisted instruction in computational biology and bioinformatics.

Computational Biology and Bioinformatics (CBB) are indispensable components in the training of life scientists [1]–[3]. Current curricula in the life sciences should prepare graduates who master quantitative and computer skills for increased levels of performance [4]–[6]. Equally important is that the application of the curricula is driven by an appropriate instructional paradigm and effective learning experiences. Teaching and learning with computers bring specific issues that should be considered beforehand by any instructor. The following Quick Guide for Computer-Assisted Instruction (CAI) outlines ten principles for effective teaching. The principles are aligned with current developments on human cognition and learning [7] and have been drawn from our own experience using CAI in seminars, tutorials, and distance education, in courses on Molecular Life Sciences at the undergraduate level, taught to majors in biology or in other subjects (e.g., nutrition, teaching of physics and chemistry, teaching of biology, sports). The Guide refers to the preparation, presentation, and assessment of CAI. It should be an aid for those who teach CBB with CAI in class, and it is expected to stimulate student motivation and deeper learning in CBB, thus making class time more effective and improving satisfaction of both students and instructors.

Adapting a Biochemistry Course to Distance Education

Internet‐based distance education seems to be an attractive alternative to offer courses dealing with specific topics that are not conveniently explored in undergraduate courses. This is a good way to provide access to the recent and updated discoveries in this research area and to reach people who could not take the classes in the traditional mode. Using the communication advantages available via the Internet, we adapted the course “Biochemistry of Nutrition,” first offered as a summer course to be entirely carried out at distance. The adaptation explored the use of online tools such as E‐mail communication among students and teachers, computer conferencing in small groups to discuss specific subjects, and texts and software downloads to be used as main references. Graduate students had their first real experience as teachers, which proved to be very productive for both the development of the Internet version of the course and their integration with undergraduate students.

Different energy sources in sports: Introductory software†

This work describes software designed to promote the association between the content of a basic undergraduate biochemistry course and the professional activities of physical education students. The software contains three main content sections: (A) Structure of skeletal muscle, (B) Contraction mechanism, and (C) Adaptations to physical exercise. A fourth section asks questions of the students. The software offers students a brief introduction on muscle structure and function, focusing on the energy sources required by different kinds of physical activities. The software was field tested at Universidade Estadual de Campinas (Unicamp), Brazil and has been adopted by several Brazilian universities. The students are required to examine the software, to discuss its contents, and to produce a list of questions arising from their work with the software. These questions are answered during the development of the curriculum, thereby connecting biochemical knowledge with the energetic needs for the practice of sports.

A suitable procedure to choose antimicrobials as controlling agents in fermentations performed by bacteria

This work evaluated the influence of nitrofurantoin, erythromycin and streptomycin at 50, 25 and 12,5% of the minimal inhibitory concentration (MIC) on maximum specific growth rate (µmax) and specific polymer accumulation rate (µPHB) of Alcaligenes eutrophus, considered resistant to those antimicrobials. Nitrofurantoin strongly affected µmax even at 50% MIC. Streptomycin moderately affected µmax only at 50%MIC. Nitrofurantoin showed the most harmful effect on µPHB when 50% MIC was applied and erythromycin was not harmful.

An Advance Organizer for Teaching Bacterial Metabolism.

The metabolic versatility of bacteria is a source of learning difficulty for students in classical microbiology courses. To facilitate the learning process, the authors developed an advance organizer. It consists of a set of six diagrams of metabolic pathways describing the basic living requirements of several types of bacteria: energy, carbon sources, and oxidizable substrates that provide electrons for reductive biosyntheses. The students are presented with the six diagrams and at the same time with one problem that must be resolved using solely the set of diagrams, with no access to any textbook. This procedure aims at developing the skills necessary to analyze different (and perhaps more complex) metabolic processes than those represented by the diagrams.

Oxygen consumption by isolated mitochondria: Software for planning and interpreting experiments

Abstract A computer program for teaching is described which stimulates oxygen consumption by isolated mitochondria. The effects of different compounds (substrates, inhibitors, uncouplers) may be tested. Results from evaluation with 166 undergraduate and 11 postgraduate students are presented.

Radicais livres de oxigênio: um software introdutório

Though Free Radicals is one of the most frequently explored scientific subjects in mass communication media, the topic is absent of many Biochemistry introductory courses, especially those in which the students do not have a good chemical background. To overcome this contradictory situation we have developed a software treating this topic in a very simple way. The software is divided in four sections: (1) definition and description of free radicals, (2) production pathways, (3) mechanism of action and (4) enzymatic and non enzymatic protection. The instructional capacity of the software has been both qualitative and quantitatively evaluated through its application in undergraduate courses. The software is available in the INTERNET at the site: http://www.unicamp.br/ib/bioquimica/ensino.

Biochemistry of the envenomation response-A generator theme for interdisciplinary integration.

The understanding of complex physiological processes requires information from many different areas of knowledge. To meet this interdisciplinary scenario, the ability of integrating and articulating information is demanded. The difficulty of such approach arises because, more often than not, information is fragmented through under graduation education in Health Sciences. Shifting from a fragmentary and deep view of many topics to joining them horizontally in a global view is not a trivial task for teachers to implement. To attain that objective we proposed a course herein described—Biochemistry of the envenomation response—aimed at integrating previous contents of Health Sciences courses, following international recommendations of interdisciplinary model. The contents were organized by modules with increasing topic complexity. The full understanding of the envenoming pathophysiology of each module would be attained by the integration of knowledge from different disciplines. Active‐learning strategy was employed focusing concept map drawing. Evaluation was obtained by a 30‐item Likert‐type survey answered by ninety students; 84% of the students considered that the number of relations that they were able to establish as seen by concept maps increased throughout the course. Similarly, 98% considered that both the theme and the strategy adopted in the course contributed to develop an interdisciplinary view.

AMPc - Sinalização intracelular: um software educacional

Chemicals binding to membrane receptors may induce events within the cell changing its behavior. Since these events are simultaneous and hard to be understood by students, we developed a computational model to dynamically and visually explore the cAMP signaling system to facilitate its understanding. The animation is shown in parts, from the hormone-receptor binding to the cellular response. There are some questions to be answered after using the model. The software was field-tested and an evaluation questionnaire (concerning usability, animations, models, and the software as an educational tool) was answered by the students, showing the software to be a valuable aid for content comprehension.