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- MINIREVIEW] Stress responses in Streptococcus species and their effects on the host
- Cuong Thach Nguyen , Sang-Sang Park , Dong-Kwon Rhee
- J. Microbiol. 2015;53(11):741-749. Published online October 28, 2015
- DOI: https://doi.org/10.1007/s12275-015-5432-6
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- 25 Citations
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Abstract
- Streptococci cause a variety of diseases, such as dental caries, pharyngitis, meningitis, pneumonia, bacteremia, endocarditis, erysipelas, and necrotizing fasciitis. The natural niche of this genus of bacteria ranges from the mouth and nasopharynx to the skin, indicating that the bacteria will inevitably be subjected to environmental changes during invasion into the host, where it is exposed to the host immune system. Thus, the Streptococcus-host interaction determines whether bacteria are cleared by the host’s defenses or whether they survive after invasion to cause serious diseases. If this interaction was to be deciphered, it could aid in the development of novel preventive and therapeutic agents. Streptococcus species possess many virulent factors, such as peroxidases and heat-shock proteins (HSPs), which play key roles in protecting the bacteria from hostile host environments. This review will discuss insights into the mechanism(s) by which streptococci adapt to host environments. Additionally, we will address how streptococcal infections trigger host stress responses; however, the mechanism by which bacterial components modulate host stress responses remains largely unknown.
Research Support, Non-U.S. Gov't
- Heat- and Cold-Shock Responses in Fusarium graminearum 3 Acetyl- and 15 Acetyl-Deoxynivalenol Chemotypes
- Vladimir Vujanovic , Yit Kheng Goh , Prasad Daida
- J. Microbiol. 2012;50(1):97-102. Published online February 27, 2012
- DOI: https://doi.org/10.1007/s12275-012-1381-5
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- 23 Citations
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Abstract
- Fusarium graminearum Schwabe is the primary cause of Fusarium head blight (FHB) in North America. Chemically distinct F. graminearum sub-populations can be identified based on the type or composition of deoxynivalenol (DON) mycotoxin derivatives, including 3-acetyl (3-ADON) and 15-acetyl (15-ADON). The evaluation of randomly selected 3-ADON and 15-ADON isolates, collected from spring wheat throughout Canada, was performed using thin layer chromatography (TLC), high-performance liquid chromatography (HPLC), ice-nucleation activity (INA), and heat and cold tolerance tests conducted within a temperature range of -70°C to 65°C. The results indicated that the 3-ADON sub-population, which is responsible for the highest disease severity and has rapidly displaced the 15-ADON sub-population, produces more DON and zearalenone (ZEA) than the 15-ADON sub-population when exposed to heat and cold. Following exposures (1 and 2 h) to extremely high or low temperatures, 3-ADON isolates exhibited faster mycelial growth than 15-ADON isolates. In addition, the warmest temperature at which INA activity occurred was in 3-ADON (-3.6°C) vs. 15-ADON (-5.1°C). Taken together, these features suggest that the newly emerging 3-ADON sub-population is more resilient than the resident 15-ADON sub-population. Overall, the differences between the two sub-populations could provide new insights into FHB epidemiology and if validated under field conditions, may provide important information for predicting future FHB epidemics.
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