2023
Biomembranes
Name: Biomembranes
Code: QUI00347L
6 ECTS
Duration: 15 weeks/156 hours
Scientific Area:
Biochemistry
Teaching languages: Portuguese
Languages of tutoring support: Portuguese, English
Regime de Frequência: Presencial
Sustainable Development Goals
Learning Goals
The aim of his course is to confer knowledge on biomembranes structure and function as well as in some methodologies used in its study
It is expected that the students acquire knowledge on:
u The structure and function of biomembranes
u The transport mechanisms across biomembranes and their regulation
u Signal transduction across biomembranes: Receptors for neurotransmitters and hormones
u Signal transduction mechanistic and regulation
u Methodologies used for the study of biomembranes structure and function
And develop skills on:
u Methodologies used for the preparation of synthetic membranes and its quality control.
u Methodologies used for the preparation of membrane vesicles and manipulation of intact cells.
u Methodologies used for the study of biomembranes structure and function
It is expected that the students acquire knowledge on:
u The structure and function of biomembranes
u The transport mechanisms across biomembranes and their regulation
u Signal transduction across biomembranes: Receptors for neurotransmitters and hormones
u Signal transduction mechanistic and regulation
u Methodologies used for the study of biomembranes structure and function
And develop skills on:
u Methodologies used for the preparation of synthetic membranes and its quality control.
u Methodologies used for the preparation of membrane vesicles and manipulation of intact cells.
u Methodologies used for the study of biomembranes structure and function
Contents
Lecture component
1. Introduction
¡ Objectives of this course
¡ Biomembranes: I) introduction to its chemical composition, structure and function; II) review of proposed models of biomembranes structure
2. Membrane lipids
¡ Phospholipids, glucolipids and cholesterol
¡ Lipid compositional changes among tissues
¡ Aspects of macromolecular organization of membrane lipids: Monolayers, micelles and liposomes
3. Physical aspects of biomembranes
¡ Fluidity and dynamic of biomembranes
¡ Electrical properties of biomembranes
4. Biosynthesis of membrane lipids and biomembranes
¡ Synthesis, transport e distribution of membrane lipids
¡ Synthesis and insertion of protein into biomembranes
¡ Association of lipids and proteins in biomembranes: Lipid protein interactions
5. Membrane-bound enzymes
¡ Molecular structure of membrane bound enzymes: Peripheral, anchored and transmembrane enzymes
¡ Sidedness and topography of membrane enzymes
¡ Consequences of membrane biding: Role of lipid protein interaction (lipid annulus); Substrate compartmentalization; Bidimensional diffusion
6. Transmembrane transport
¡ Thermodynamic of the do transport: Passive diffusion and primary and secondary transport
¡ Kinetic and mechanism of the transport
¡ Diversity of transport in bacteria
7. Ionic Transport
¡ Ion pumps, exchangers and channels
¡ Ionophores: Structure and mechanism of action
8. Ion channels
¡ Structure and function
¡ Kinetic properties and regulation
9. Electrical properties of biomembranes
¡ Membrane potential and electrical activity
¡ Electrophysiological methods
10. Signal transduction across biomembranes
¡ Receptors for neurotransmitters: Structure and function
¡ Receptors for peptide hormones: Structure and function
¡ Intracellular messengers in signal transduction:
o G-proteins and Ras proteins
o cAMP and cGMP in signal transduction;
o Phospholipases and phospholipids in signal transduction;
o Membrane associated protein kinases and phosphatases;
o The role of Ca2+
¡ Receptors and the intracellular messenger cascades
11. Intracellular vesicular trafficking
¡ Membrane transport: Vesicle formation and transport; Vesicle coating and trafficking; Involvement of microtubules
¡ Regulated endocytosis
¡ Exocytosis: Molecular mechanism of vesicle fusion
12. Biomembranes: production and isolation
¡ Extraction, purification and reconstitution of membrane lipids and proteins
¡ Synthetic membranes
¡ Native membrane isolation
13. Biomembranes in industry
¡ Application n the pharmaceutical and cosmetic industry
Practical Component
1. Introduction
2. Lipid composition of biomembranes
¡ Separation and identification of membrane lipids
- Preparation of a membrane lipid extract.
- Identification of membrane lipids using specific chemical tests.
3. Biophysical properties of biomembranes
¡ Determination of the phase transition temperature of synthetic liposomes of DPPC and DPPC and cholesterol
- Synthesis of multilamelar DPPC liposomes and DPPC plus cholesterol liposomes.
- Transition phase determination by using a turbidimetric method.
- Effect of the inclusion of cholesterol in the membranes on the phase transition temperature.
4. Biomembranes permeability
¡ Effect of cholesterol in the permeability of DPPC liposomes to glycerol and ethylenglycol
- Diffusion of glycerol and ethylenglycol through DPPC liposomes.
- Effect of the molecular weight and polarity in the diffusion of molecules.
- Effect of cholesterol in the permeability of lipid bilayers.
5. Electric properties and ionic permeability of biomembranes
¡ Membrane potential measurements using a TPP+ electrode
- Preparation of sinaptosomes.
- Basal membrane potential (Vm) measurement.
- Effect of K+ e Ca2+ ionic gradients on sinaptosomes Vm.
- Effect of the activation of voltage dependent Na+ channels by veratridine.
- Effect of the inhibition of Na+,K+-ATPase on Vm.
6. Active transport across biomembranes
¡ Ca2+ transport into the endoplasmic reticulum by the Ca2+-ATPase (SERCA)
- Preparation of endoplasmic reticulum membrane vesicles (microsommes).
- Effect of ATP concentration on the Ca2+-ATPase activity.
7. Enzymatic activity of the biomembranes
¡ Study of the enzymatic activity of Na+,K+-ATPase in sinaptossomes.
- Total ATPase activity.
- Selective inhibition of Na+,K+-ATPase with ouabain and determination of Na+,K+-ATPase activity.
- Na+,K+-ATPase activity dependence on Na+, K+ and ATP concentration.
8. Signal transduction across biological membranes and hormone secretion
¡ Insulin secretion from islets of Langerhans and its regulation
- Isolation of islet of Langerhans using an enzymatic method.
- Glucose-evoked insulin secretion: Effect of glucose concentration.
- Effect of Ca2+ concentration and the inhibition of voltage dependent Ca2+ channels.
- Effect of agonists of membrane receptors.
1. Introduction
¡ Objectives of this course
¡ Biomembranes: I) introduction to its chemical composition, structure and function; II) review of proposed models of biomembranes structure
2. Membrane lipids
¡ Phospholipids, glucolipids and cholesterol
¡ Lipid compositional changes among tissues
¡ Aspects of macromolecular organization of membrane lipids: Monolayers, micelles and liposomes
3. Physical aspects of biomembranes
¡ Fluidity and dynamic of biomembranes
¡ Electrical properties of biomembranes
4. Biosynthesis of membrane lipids and biomembranes
¡ Synthesis, transport e distribution of membrane lipids
¡ Synthesis and insertion of protein into biomembranes
¡ Association of lipids and proteins in biomembranes: Lipid protein interactions
5. Membrane-bound enzymes
¡ Molecular structure of membrane bound enzymes: Peripheral, anchored and transmembrane enzymes
¡ Sidedness and topography of membrane enzymes
¡ Consequences of membrane biding: Role of lipid protein interaction (lipid annulus); Substrate compartmentalization; Bidimensional diffusion
6. Transmembrane transport
¡ Thermodynamic of the do transport: Passive diffusion and primary and secondary transport
¡ Kinetic and mechanism of the transport
¡ Diversity of transport in bacteria
7. Ionic Transport
¡ Ion pumps, exchangers and channels
¡ Ionophores: Structure and mechanism of action
8. Ion channels
¡ Structure and function
¡ Kinetic properties and regulation
9. Electrical properties of biomembranes
¡ Membrane potential and electrical activity
¡ Electrophysiological methods
10. Signal transduction across biomembranes
¡ Receptors for neurotransmitters: Structure and function
¡ Receptors for peptide hormones: Structure and function
¡ Intracellular messengers in signal transduction:
o G-proteins and Ras proteins
o cAMP and cGMP in signal transduction;
o Phospholipases and phospholipids in signal transduction;
o Membrane associated protein kinases and phosphatases;
o The role of Ca2+
¡ Receptors and the intracellular messenger cascades
11. Intracellular vesicular trafficking
¡ Membrane transport: Vesicle formation and transport; Vesicle coating and trafficking; Involvement of microtubules
¡ Regulated endocytosis
¡ Exocytosis: Molecular mechanism of vesicle fusion
12. Biomembranes: production and isolation
¡ Extraction, purification and reconstitution of membrane lipids and proteins
¡ Synthetic membranes
¡ Native membrane isolation
13. Biomembranes in industry
¡ Application n the pharmaceutical and cosmetic industry
Practical Component
1. Introduction
2. Lipid composition of biomembranes
¡ Separation and identification of membrane lipids
- Preparation of a membrane lipid extract.
- Identification of membrane lipids using specific chemical tests.
3. Biophysical properties of biomembranes
¡ Determination of the phase transition temperature of synthetic liposomes of DPPC and DPPC and cholesterol
- Synthesis of multilamelar DPPC liposomes and DPPC plus cholesterol liposomes.
- Transition phase determination by using a turbidimetric method.
- Effect of the inclusion of cholesterol in the membranes on the phase transition temperature.
4. Biomembranes permeability
¡ Effect of cholesterol in the permeability of DPPC liposomes to glycerol and ethylenglycol
- Diffusion of glycerol and ethylenglycol through DPPC liposomes.
- Effect of the molecular weight and polarity in the diffusion of molecules.
- Effect of cholesterol in the permeability of lipid bilayers.
5. Electric properties and ionic permeability of biomembranes
¡ Membrane potential measurements using a TPP+ electrode
- Preparation of sinaptosomes.
- Basal membrane potential (Vm) measurement.
- Effect of K+ e Ca2+ ionic gradients on sinaptosomes Vm.
- Effect of the activation of voltage dependent Na+ channels by veratridine.
- Effect of the inhibition of Na+,K+-ATPase on Vm.
6. Active transport across biomembranes
¡ Ca2+ transport into the endoplasmic reticulum by the Ca2+-ATPase (SERCA)
- Preparation of endoplasmic reticulum membrane vesicles (microsommes).
- Effect of ATP concentration on the Ca2+-ATPase activity.
7. Enzymatic activity of the biomembranes
¡ Study of the enzymatic activity of Na+,K+-ATPase in sinaptossomes.
- Total ATPase activity.
- Selective inhibition of Na+,K+-ATPase with ouabain and determination of Na+,K+-ATPase activity.
- Na+,K+-ATPase activity dependence on Na+, K+ and ATP concentration.
8. Signal transduction across biological membranes and hormone secretion
¡ Insulin secretion from islets of Langerhans and its regulation
- Isolation of islet of Langerhans using an enzymatic method.
- Glucose-evoked insulin secretion: Effect of glucose concentration.
- Effect of Ca2+ concentration and the inhibition of voltage dependent Ca2+ channels.
- Effect of agonists of membrane receptors.
Teaching Methods
28h lectures
30h practicals
2h tutorial
30h practicals
2h tutorial
Assessment
EVALUATION
According to the Internal Regulation, attendance to lecture classes is optional but attendance to the laboratory classes is obligatory.
Admissions to evaluation examination will require attendance to at least 75% of the laboratorial activities. Students who possess Working-student permit and are unable to attend laboratory activities will have to submit to a final examination in order to evaluate their laboratorial skills.
The examination of this course will have a theoretical component and a practical component and two optional modalities to achieve the grade: continuous examination and a final exam.
EVALUATION MODALITIES
The theoretical evaluation will consist in written test with a maximum score of 20 values each.
The practical evaluation will consist in a laboratorial examination at the end of the semester, the evaluation of the laboratorial skills acquired, shown during the realization of laboratory work and the interpretation of results, the written essays produced by the students during the semester and paper presentations.
Evaluation through the semester
Theoretical Component
The theoretical evaluation will consist of two written tests, one at the middle of the semester (about the first part of the contents) and another one at the end of the semester (25% of it about the 1st part of the issues and 75% about the 2nd part).
The final score will be equal to 40% of the 1st test (minimum score accepted: 10 values) plus 60% of the 2nd test (minimum score accepted: 8 values).
Laboratorial Component
The final score of this component will result from 40% of the score of the written essays, 30% of the laboratorial skills evaluation (including paper presentations) and another 30% corresponding to a practical examination (minimum score to achieve grade: 10 values in all components).
Final Grade Calculation
The final score of a student who granted approval in all components will correspond to 50% of the theoretical component plus 50% of the laboratorial component scores.
Exam evaluation
Theoretical Component
This will consist in a written test concerning all the content of this course.
Laboratorial Component
The final score of this component will result from 40% of the score of the written essays, 30% of the laboratorial skills evaluation and another 30% corresponding to a practical examination (minimum score to achieve grade: 10 values in all components).
Final Grade Calculation
The final score of a student who granted approval in all components will correspond to 50% of the theoretical component plus 50% of the laboratorial component scores.
According to the Internal Regulation, attendance to lecture classes is optional but attendance to the laboratory classes is obligatory.
Admissions to evaluation examination will require attendance to at least 75% of the laboratorial activities. Students who possess Working-student permit and are unable to attend laboratory activities will have to submit to a final examination in order to evaluate their laboratorial skills.
The examination of this course will have a theoretical component and a practical component and two optional modalities to achieve the grade: continuous examination and a final exam.
EVALUATION MODALITIES
The theoretical evaluation will consist in written test with a maximum score of 20 values each.
The practical evaluation will consist in a laboratorial examination at the end of the semester, the evaluation of the laboratorial skills acquired, shown during the realization of laboratory work and the interpretation of results, the written essays produced by the students during the semester and paper presentations.
Evaluation through the semester
Theoretical Component
The theoretical evaluation will consist of two written tests, one at the middle of the semester (about the first part of the contents) and another one at the end of the semester (25% of it about the 1st part of the issues and 75% about the 2nd part).
The final score will be equal to 40% of the 1st test (minimum score accepted: 10 values) plus 60% of the 2nd test (minimum score accepted: 8 values).
Laboratorial Component
The final score of this component will result from 40% of the score of the written essays, 30% of the laboratorial skills evaluation (including paper presentations) and another 30% corresponding to a practical examination (minimum score to achieve grade: 10 values in all components).
Final Grade Calculation
The final score of a student who granted approval in all components will correspond to 50% of the theoretical component plus 50% of the laboratorial component scores.
Exam evaluation
Theoretical Component
This will consist in a written test concerning all the content of this course.
Laboratorial Component
The final score of this component will result from 40% of the score of the written essays, 30% of the laboratorial skills evaluation and another 30% corresponding to a practical examination (minimum score to achieve grade: 10 values in all components).
Final Grade Calculation
The final score of a student who granted approval in all components will correspond to 50% of the theoretical component plus 50% of the laboratorial component scores.
Recommended Reading
Luís Loura & Rodrigo F.M. de Almeida (2004). Tópicos de biofísica de membranas. Edições Lidel, Lisboa Porugal
Meir Shinitzky (1994). Biomembranes Structural and functional aspects. VCH, Weinheim, FDA.
Meir Shinitzky (1995). Biomembranes Signal transduction across membranes. VCH Inc., Weinheim, RFA.
Malcolm N. Jones & Dennis Chapman (1995). Micelles, monolayers and biomembranes. John Wiley & Sons Inc., Chichester, UK.
Vladimir P. Torchilin & Volkmar Weissig (2003). Lipossomes: Practical Approach (2nd ed.). Oxford University Press, Oxford, UK.
Stephen A. Baldwin (2000). Membrane transport. Oxford University Press, Oxford, UK.
Jim Woodgett (2000). Protein Kinase Functions (2nd ed). Oxford University Press, Oxford, UK.
F. M. Ashcroft (2000). Ion Channels and Disease. Academic Press, London, UK.
H. Lodish, A. Berk, P. Matsudaira, C. H. Kaiser, M. Krieger, M. P. Scott, S.L. Zipursky & J. Darnell (2003) . Molecular Cell Biology (5th Ed.). W. H. Freeman & Co., England.
Mary K. Campbell & Shawn O. Farrell (2003). Biochemistry (4th Ed.). Thomson Learning, Inc., USA.
Thomas M. Devlin (1997). Textbook of Biochemistry with clinical correlations (4th Ed.). Wiley-Liss, Inc., New York, USA.
Bertil Hille (1992). Ionic channels of excitable membranes (2nd ed.). Sinauer Associates Inc., Sunderland, Massachusetts.
Colin W. Taylor (1991). Intracellular messengers - International Encyclopedia of Pharmacology and Therapeutics, Section 139. Pergamon Press, Oxford, UK.
Meir Shinitzky (1994). Biomembranes Structural and functional aspects. VCH, Weinheim, FDA.
Meir Shinitzky (1995). Biomembranes Signal transduction across membranes. VCH Inc., Weinheim, RFA.
Malcolm N. Jones & Dennis Chapman (1995). Micelles, monolayers and biomembranes. John Wiley & Sons Inc., Chichester, UK.
Vladimir P. Torchilin & Volkmar Weissig (2003). Lipossomes: Practical Approach (2nd ed.). Oxford University Press, Oxford, UK.
Stephen A. Baldwin (2000). Membrane transport. Oxford University Press, Oxford, UK.
Jim Woodgett (2000). Protein Kinase Functions (2nd ed). Oxford University Press, Oxford, UK.
F. M. Ashcroft (2000). Ion Channels and Disease. Academic Press, London, UK.
H. Lodish, A. Berk, P. Matsudaira, C. H. Kaiser, M. Krieger, M. P. Scott, S.L. Zipursky & J. Darnell (2003) . Molecular Cell Biology (5th Ed.). W. H. Freeman & Co., England.
Mary K. Campbell & Shawn O. Farrell (2003). Biochemistry (4th Ed.). Thomson Learning, Inc., USA.
Thomas M. Devlin (1997). Textbook of Biochemistry with clinical correlations (4th Ed.). Wiley-Liss, Inc., New York, USA.
Bertil Hille (1992). Ionic channels of excitable membranes (2nd ed.). Sinauer Associates Inc., Sunderland, Massachusetts.
Colin W. Taylor (1991). Intracellular messengers - International Encyclopedia of Pharmacology and Therapeutics, Section 139. Pergamon Press, Oxford, UK.
Teaching Staff
- António Manuel Teixeira Martins do Canto [responsible]
