000162579 001__ 162579
000162579 005__ 20251017144620.0
000162579 0247_ $$2doi$$a10.1128/aem.00677-25
000162579 0248_ $$2sideral$$a145059
000162579 037__ $$aART-2025-145059
000162579 041__ $$aeng
000162579 100__ $$0(orcid)0000-0003-1979-363X$$aFreire, Víctor
000162579 245__ $$aSporulation at reduced water activity impairs germination kinetics of Bacillus subtilis spores
000162579 260__ $$c2025
000162579 5060_ $$aAccess copy available to the general public$$fUnrestricted
000162579 5203_ $$aWhile the effect of sporulation temperature on spore germination has been extensively studied, the effect of other relevant environmental factors such as water activity (aw) has been overlooked, despite the fact that sporulation niches with lower humidity than ideal culture media, such as soil, are common in nature. In this work, we characterized the germination kinetics of B. subtilis 168 spores produced at reduced aw (0.98) using either glycerol (Sgly spores) or NaCl (Ssalt spores) in comparison to spores prepared under optimal conditions (Scontrol spores, aw ~0.99) in a variety of nutrient and chemical stimuli, along with the effect of thermal activation. Spores produced at reduced aw showed impaired germination to varying degrees depending on the nutrient and solute used to depress aw. While Sgly spores exhibited germination defects in all the nutrients tested (a rich growth medium, L-alanine, L-valine, and the AGFK mixture) compared to Scontrol spores, Ssalt populations showed an impaired response to L-alanine and L-valine. These nutrient germination defects of the Sgly and Ssalt spores could not be reversed by heat activation. In addition, both populations displayed impaired germination in Ca-DPA, but increased germination rate in dodecylamine. The phenotypes of spores produced at reduced aw suggested plausible alterations in their coat properties. Using mutant spores with coat morphogenesis defects and a 4 kDa FITC-dextran probe permeability test, we could infer that the impaired germination of Ssalt spores in nutrients and Ca-DPA may involve alterations in the crust and/or outer coat, leading to reduced permeability.
IMPORTANCE: Bacterial spores are causative agents of relevant zoonoses and foodborne diseases and are involved in food spoilage. Natural sporulation niches, such as soil, are exposed to a variety of changing environmental conditions, such as temperature and water activity (aw), which strongly influence the dynamics of spore germination. This work provides the first data on the effect of lowering the aw of the sporulation medium on spore germination kinetics, which, together with previous data on the effect of other environmental sporulation conditions and inter- and intraspecific variability, will help accurately predict germination and thus prevent the negative impacts of pathogenic and food spoiling spores. Furthermore, we inferred that alterations related to the coat are associated with impaired nutrient germination of spores produced at reduced aw with the addition of NaCl. These findings may help develop novel and efficient strategies to control germination or eradicate spores.
000162579 536__ $$9info:eu-repo/grantAgreement/ES/MICINN/PID2019-104712RA-I00
000162579 540__ $$9info:eu-repo/semantics/openAccess$$aby$$uhttps://creativecommons.org/licenses/by/4.0/deed.es
000162579 655_4 $$ainfo:eu-repo/semantics/article$$vinfo:eu-repo/semantics/publishedVersion
000162579 700__ $$0(orcid)0000-0002-1902-0648$$aCondón, Santiago$$uUniversidad de Zaragoza
000162579 700__ $$0(orcid)0000-0002-5895-2157$$aGayán, Elisa$$uUniversidad de Zaragoza
000162579 7102_ $$12008$$2780$$aUniversidad de Zaragoza$$bDpto. Produc.Animal Cienc.Ali.$$cÁrea Tecnología de Alimentos
000162579 773__ $$g91, 7 (2025), e00677-25 [20 pp.]$$tApplied and Environmental Microbiology$$x0099-2240
000162579 8564_ $$s3900104$$uhttps://zaguan.unizar.es/record/162579/files/texto_completo.pdf$$yVersión publicada
000162579 8564_ $$s2269123$$uhttps://zaguan.unizar.es/record/162579/files/texto_completo.jpg?subformat=icon$$xicon$$yVersión publicada
000162579 909CO $$ooai:zaguan.unizar.es:162579$$particulos$$pdriver
000162579 951__ $$a2025-10-17-14:21:14
000162579 980__ $$aARTICLE