This article has been reviewed according to Science X's editorial process and policies. Editors have highlighted the following attributes while ensuring the content's credibility: Scientists, clinicians, seed companies and others may soon have a new tool in their toolkit for detecting bacterial pathogens, thanks to a new study by researchers in Penn State's College of Agricultural Sciences. The research—published in Journal of Microbiological Methods—details a new method for detecting Pseudomonas syringae, a common bacterium that infects a wide variety of crops, vegetables and woody ornamentals.
The cost is similar to that of the traditional method, called enzyme-linked immunosorbent assay, or ELISA. However, the researchers' new method—called enzyme-linked chaperone assay, or ELCA—has the potential to detect only living bacteria, making it more sensitive and accurate. Rachel Herschlag, lead author on the paper who earned her doctorate in plant pathology at Penn State, said the study is a proof of concept, with an opportunity in the future to adapt the method for detecting other pathogens.
"Now that we've documented this method, researchers can adapt it for other bacteria that have a similar system," she said. "This could include some animal and human pathogens in addition to those affecting plants, expanding its potential utility in clinical, agricultural, environmental and biotechnology applications." Carolee Bull, professor of bacterial systematics and plant pathology and co-author of the paper, said many current diagnostic tests, like ELISA, work by using animal-derived antibodies produced to fight an infection. However, the new method uses a different mechanism.
"I asked Herschlag to think creatively about bacterial pathogen detection to develop novel strategies for detecting Pseudomonas strains and, potentially, other types of bacteria," Bull said. "She went on to develop this technique by using the same mechanism that many pathogens use to invade their hosts to allow us to recognize them." When bacteria attack plants, animals or people, they deliver specialized proteins called effectors into the host's cells, she explained. These proteins help the bacteria overcome the host's immune system and invade the organism.
To do this efficiently, many bacteria rely on helper proteins called chaperones that recognize and bind—like a lock and key—to these effectors with high specificity. The chaperones protect the effectors, which are vulnerable to degradation. The new method relies on this process rather than the labor-intensive process of harvesting antibodies in a lab.
"Unlike other diagnostics, this new method uses a bacterial chaperone to recognize and bind to its matching effector protein," Herschlag said. "This then triggers a colorless solution to turn yellow, providing an easy visual signal that the target is present. And because this interaction is highly specific, the method can reliably detect its intended target." Other diagnostic approaches, the researchers explained, work by detecting specific parts of the cell, such as DNA.
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