Journal of Immunology and Infectious Diseases

Dr. Portugal brings a wealth of diversified experience to the realm of biotechnology. He has taught extensively in both graduate biotechnology and undergraduate science programs. He has lectured in traditional face-to-face classrooms; developed, trained, taught, and used curricula materials in virtual classrooms online; and advocated methods and reasons for the incorporation of digital media in both graduate and undergraduate coursework.

Dr. Portugal has participated in historical and fundamental molecular biological studies with Dr. Marshall Nirenberg, Nobel Laureate for the discovery of the genetic code, and with Dr. Dolph Hatfield, which led to the discovery of the 21st amino acid selenocysteine. He has co-invented and patented a novel instrument for biotechnological analysis, as well as conducted experiments on possible new pathways that control of the growth of human bacterial pathogens.

Dr. Portugal has founded a start-up biotechnology company, set up entire biotechnological laboratories from scratch, competed successfully for grant support from federal and state agencies, and formed collaborations with leading scientists, engineers, and pharmaceutical companies both in the local Washington area and around the country. In addition, he has written business plans for biotechnology companies that panels of scientists and business people alike have validated.

Dr. Portugal's laboratory has two main areas of interest. The first is the investigation of factors secreted by certain pathogenic bacteria that can self-inhibit the pathogen's own growth. These factors appear distinct from quorum sensors, which do not inhibit growth but switch on the expression of virulence genes when pathogens enter the stationary phase of growth in culture. Quorum sensors for Gram negative bacteria are derivatives of homoserine lactones, whereas quorum sensors for Gram positive bacteria are small peptides. Furthermore, these unknown factors also appear to be different from bacteriocins, which bacteria secrete and which prevent growth of competing organisms but not the bacterial species that secreted the factor. Our investigations center on the exact chemical structure for the self-inhibitory factors from both Gram negative and Gram positive organisms. Once the structures are known, we will investigate what regulates expression of these factors during growth, and how these factors might be used to treat patients with serious infections who are not responding well to antibiotics.

The second area of interest is the application of a novel and highly sensitive biosensor that uses molecular interactions to identify pathogens and/or biological materials. This patented biosensor was developed in collaboration with faculty at the University of Maryland, College Park. The biosensor combines biotechnological principles with a fiber optic-based operating system that employs a near-infrared laser to create a positive fluorescent signal. After passage through a photoelectric tube that converts light impulses into electric ones, the pulses are then amplified by many magnitudes-of order. The electric signals are then detected and displayed on an oscilloscope. Current applications of this system include uses in medicine, agriculture, and biological warfare.