Heat Activation and Inactivation of Bacterial Spores: Is There an Overlap?

Appl Environ Microbiol

Molecular Biology and Microbial Food Safety, Swammerdam Institute for Life Sciences, University of Amsterdam, Amsterdam, The Netherlands.

Published: March 2022

Heat activation at a sublethal temperature is widely applied to promote species spore germination. This treatment also has the potential to be employed in food processing to eliminate undesired bacterial spores by enhancing their germination and then inactivating the less-heat-resistant germinated spores at a milder temperature. However, incorrect heat treatment could also generate heat damage in spores and lead to more heterogeneous spore germination. Here, the heat activation and heat damage profile of Bacillus subtilis spores was determined by testing spore germination and outgrowth at both population and single-spore levels. The heat treatments used were 40 to 80°C and for 0 to 300 min. The results were as follows. (i) Heat activation at 40 to 70°C promoted l-valine- and l-asparagine-glucose-fructose-potassium (AGFK)-induced germination in a time-dependent manner. (ii) The optimal heat activation temperatures for AGFK and l-valine germination via the GerB plus GerK or GerA germinant receptors were 65°C and 50 to 65°C, respectively. (iii) Heat inactivation of dormant spores appeared at 70°C, and the heat damage of molecules essential for germination and growth began at 70 and 65°C, respectively. (iv) Heat treatment at 75°C resulted in both activation of germination and damage to the germination apparatus, and 80°C treatment caused more pronounced heat damage. (v) For the spores that should withstand adverse environmental temperatures in nature, heat activation seemed functional for a subsequent optimal germination process, while heat damage affected both germination and outgrowth. Bacterial spores are thermal-stress-resistant structures that can thus survive food preservation strategies and revive through the process of spore germination. The more heat resistant spores are, the more heterogeneous their germination upon the addition of germinants. Upon germination, spores can cause food spoilage and food intoxication. Here, we provide new information on both heat activation and inactivation regimes and their effects on the (heterogeneity of) spore germination.

Download full-text PDF

Source
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8904049PMC
http://dx.doi.org/10.1128/aem.02324-21DOI Listing

Publication Analysis

Top Keywords

heat activation
28
spore germination
20
heat damage
20
heat
17
germination
15
bacterial spores
12
spores
10
activation inactivation
8
heat treatment
8
damage spores
8

Similar Publications

Transient receptor potential channel subfamily M member 3 (TRPM3) is a Ca-permeable cation channel activated by the neurosteroid pregnenolone sulfate (PregS) or heat, serving as a nociceptor in the peripheral sensory system. Recent discoveries of autosomal dominant neurodevelopmental disorders caused by gain-of-function mutations in TRPM3 highlight its role in the central nervous system. Notably, the TRPM3 inhibitor primidone, an anticonvulsant, has proven effective in treating patients with TRPM3-linked neurological disorders and in mouse models of thermal nociception.

View Article and Find Full Text PDF

This study aimed to investigate the impact of adding aroeira leaf extract (Schinus terebinthifolius Raddi) to a yam starch film matrix, focusing on the development of potentially active films and the evaluation of their physicochemical, mechanical, optical, and antioxidant properties. Films were produced using the casting method with varying extract concentrations (0, 3, 6, 12, and 15 %), yam starch (2 %), and glycerol (1 %). The antioxidant properties were analyzed by determining the total phenolic content, 2,2-Diphenyl-1-Picrylhydrazyl (DPPH) radical scavenging, ferric reducing power, and 2,2-azinobis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical elimination, which revealed a significant increase in antioxidant properties as the extract concentration increased.

View Article and Find Full Text PDF

DNAJC15 is a mitochondrial TIMM23-related co-chaperonin known for its role in regulating oxidative phosphorylation efficiency, oxidative stress response and lipid metabolism. Recently, it has been proposed that the loss of DNAJC15 correlates with cisplatin (CDDP)-resistance onset in ovarian cancer (OC), suggesting this protein as a potential prognostic factor during OC progression. However, the molecular mechanisms through which DNAJC15 contributes to CDDP response remains poorly investigated.

View Article and Find Full Text PDF

The association between short-term apparent temperature exposure and human coagulation: A time-series study from Beijing, 2014-2023.

Environ Int

January 2025

Department of Occupational and Environmental Health Sciences, School of Public Health, Peking University, Beijing 100191, China; Beijing Key Laboratory of Toxicological Research and Risk Assessment for Food Safety, School of Public Health, Peking University, Beijing 100083, China.

A growing body of evidence suggests that non-optimal ambient temperatures are associated with increased incidence rate and mortality of thromboembolic diseases. We aim to investigate the association between apparent temperature (AT) and coagulation, which is a central pathological link in the formation of thrombi. In this study, we conducted a time series analysis using data from 18,894 participants collected from a health check-up center in Beijing between 2014 and 2023, and validated our findings using 20,549 participants from an andrology outpatient clinic.

View Article and Find Full Text PDF

GlSIRT1 deacetylates and activates pyruvate kinase to improve pyruvate content and enhance heat stress resistance in Ganoderma lucidum.

Microbiol Res

January 2025

Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture and Rural Affairs, PR China; Microbiology Department, College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, Jiangsu, PR China. Electronic address:

Heat stress is a prevalent environmental stressor. Previous studies have shown that heat stress drives many cellular changes in Ganoderma lucidum. Interestingly, glycolysis is activated during heat stress, which could contribute to increased heat resistance.

View Article and Find Full Text PDF

Want AI Summaries of new PubMed Abstracts delivered to your In-box?

Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!