Academic Training

- Biochemist, Universidad de Concepción, Chile 1977.
- Ph.D., Cell and Molecular Biology, Universidad Austral de Chile, Chile, 1989.
- Postdoctorate, Roche Institute of Molecular Biology, USA. (1990-1992)


Scientific Interests

High density lipoprotein (HDL) is present in the blood of all known vertebrates and it has been clearly established that it possesses several protective functions. The antiatherogenic function of HDL is that which has been most studied, and which involves multiple biological activities, such as reverse transport of cholesterol, direct action on endothelial cells, antioxidant, antithrombotic and anti-inflammatory actions. Other emerging defence functions described for HDL and its apolipoproteins A-I and AII (ApoA-I, ApoA-II) in higher vertebrates include antimicrobial and antiviral activities, among others. Recent advances in proteomics techniques have demonstrated that large quantities of different proteins and peptides are to be found associated with the HDL particle. Identification of some of these proteins has contributed to the discovery of new complementary functions for HDL. The new view of HDL is that it constitutes a heterogenic family of particles that serve as a platform for assembly of proteins that play an important role in lipid metabolism and innate immunity. Our laboratory has demonstrated ApoA-I expression and has detected the presence of HDL particles in different tissues of fish Cyprinus carpio and Oncorynchus mykiss. We have also shown for the first time, in fish, that HDL, ApoA-I and ApoA-II would form part of the innate immune system. We are specifically interested in characterizing the mechanism of antibacterial action of HDL and its apolipoproteins isolated from fish and also in studying the relation between patterns of HDL-associated minority proteins present in different tissues with specific biological functions.
Another of our research lines follows peptides with antimicrobial activity (PAMs). Continuous and poorly controlled antibiotic use has led to the development of multi-resistant bacterial strains worldwide. This represents a serious problem, for both human and animal health. Further research in this area is urgently needed, as well as the development of new molecules capable of replacing or supplementing antibiotic action. With this in mind, PAMs, which are natural components of the innate immune system, constitute a still barely explored source of macromolecules with huge therapeutic and biotechnology potential. In this context, the main aim of this new research line is to identify and characterize functions of new peptides with antimicrobial activities from endemic aquatic organisms.

Relevant Publications

- Villarroel F., Bastías A., Casado A., Amthauer R., and Concha M.I. (2007) Apolipoprotein A-I, an antimicrobial protein in Oncorhynchus mykiss: Evaluation of its expression in primary defence barriers and plasma levels in sick and healthy fish. Fish Shelfish Immunol. 23:197-209

- Concha, M.I., Báez, N., Villanueva, J. y Amthauer, R. Undetectable apolipoprotein A-I gene expression suggests an unusual mechanism of dietary lipid mobilisation in the intestine of Cyprinus carpio. J. Exp. Biol. 208: 1393-1399 (2005)

- Concha, M.I., Smith, V.J., Castro, K., Bastías, A., Romero, A. y Amthauer, R. (2004) Apolipoproteins A-I and A-II are potentially important effectors of innate immunity in the teleost fish Cyprinus carpio. Eur. J. Biochem. 271: 2984-2990.

- Concha, M.I., Santander, C., Villanueva, J. y Amthauer, R. Specific binding of the endocitosis tracer horseradish peroxidase to intestinal fatty acid-binding protein (I-FABP) in apical membranas of carp enterocytes. J. Exp. Zool. 293: 541-550. (2002)

- Amthauer, R., Kodukula, K., Gerber, L. and Udenfriend, S. Involvment of BiP/GRP 78 in the biosynthesis of glycosylphosphatidylinositol-anchored membrane proteins. Proc. Natl. Acad. Sci. USA 90, 3973 3977 (1993).

- Amthauer,R., Villanueva,J., Vera,M.I., Concha,M., and Krauskopf,M. Characterization of the major plasma apolipoproteins of the high density lipoprotein in the carp (Cyprinus carpio). Comp. Biochem. Physiol. 92B, 787-793 (1989).

Photo Gallery

Phone: 222774 / Fax: 221107
Campus Isla Teja / Valdivia

- Lipoprotein structure and function
- Antimicrobial peptides

- Dra. Margarita Concha

Postgraduate Students:
- Alin Casado

Undergraduate Students:
- Jorge Vasquez
- Ella Matamala
- Bruno Araneda
- Jaqueline Plaza
- Mauricio Hernández

Research Collaborators
(or Collaborating Institutions)
- Dra. Valerie Smith (Univ. St.
Andrews, Escocia)
- Dr. Luis Mercado (Univ.
Católica Valparaíso)
- Dr. Ricardo Enríquez
(Universidad Austral de Chile)

Technical Personnel:
- Franz Villarroel (BQ)

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