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Land plant bodies develop from stem cells located in meristems. However, we know little about how meristems initiate from non-meristematic cells. The haploid body of bryophytes develops from unicellular spores in isolation from the parental plant, which allows all stages of development to be observed. We discovered that the Marchantia spore undergoes a series of reproducibly oriented cell divisions to generate a flat prothallus on which a meristem later develops de novo. The young sporeling comprises an early cell mass. One cell of the early cell mass elongates and undergoes a formative division that produces the prothalloblast, which initiates prothallus formation. A symmetric division of the prothalloblast followed by two transverse divisions generates a four-celled plate that expands into a flat disc through oblique divisions in three of the four plate-cell-derived quadrants. One quadrant gives rise to a flat flabellum. A notch with a meristem and apical stem cell develops at the margin of the flabellum. The transcription factor Marchantia class III homeodomain-leucine-zipper (MpC3HDZ) is a marker of the first flat prothallus structure and polarizes to the dorsal tissues of flabella and meristems. Mp c3hdz mutants are defective in setting up dorsoventrality and thallus body flatness. We report how a regular set of cell divisions forms the prothallus—the first dorsoventral structure—and how cells on the margin of the prothallus develop a dorsoventralized meristem de novo. [Display omitted] • Marchantia polymorpha develops meristems from single-celled spores • The sporeling forms a prothalloblast to initiate the first flat prothallus • A meristem is formed de novo on the flat prothallus flabellum • MpC3HDZ regulates dorsoventrality and marks the dorsal side of the prothallus Wallner and Dolan describe the cell division patterns that form the flat Marchantia prothallus from a single-celled spore. A meristem with an apical stem cell develops on the prothallus to initiate indeterminate thallus growth. The transcription factor MpC3HDZ marks the first flat structure and regulates dorsoventrality of the flat Marchantia body. [ABSTRACT FROM AUTHOR]

YabG is a sporulation‐specific protease that is conserved among sporulating bacteria. Clostridioides difficile YabG processes the cortex destined proteins preproSleC into proSleC and CspBA to CspB and CspA. YabG also affects synthesis of spore coat/exosporium proteins CotA and CdeM. In prior work that identified CspA as the co‐germinant receptor, mutations in yabG were found which altered the co‐germinants required to initiate spore germination. To understand how these mutations in the yabG locus contribute to C. difficile spore germination, we introduced these mutations into an isogenic background. Spores derived from C. difficile yabGC207A (a catalytically inactive allele), C. difficile yabGA46D, C. difficile yabGG37E, and C. difficile yabGP153L strains germinated in response to taurocholic acid alone. Recombinantly expressed and purified preproSleC incubated with E. coli lysate expressing wild type YabG resulted in the removal of the presequence from preproSleC. Interestingly, only YabGA46D showed any activity toward purified preproSleC. Mutation of the YabG processing site in preproSleC (R119A) led to YabG shifting its processing to R115 or R112. Finally, changes in yabG expression under the mutant promoters were analyzed using a SNAP‐tag and revealed expression differences at early and late stages of sporulation. Overall, our results support and expand upon the hypothesis that YabG is important for germination and spore assembly and, upon mutation of the processing site, can shift where it cleaves substrates. [ABSTRACT FROM AUTHOR]

BACKGROUND AND OBJECTIVES: Trichoderma species (Trichoderma sp.) is commonly found in nature, particularly in soil and roots, often thriving in plants rich in cellulose such as oil palm. Therefore, this study aimed to characterize Trichoderma sp. in each substrate as well as to assess cellulolytic and ligninolytic potential in vitro using a specific medium. Characterization and utilization of the plant were examined to efficiently manage empty fruit bunch (EFB) waste in Indonesian oil palm plantations. By exploring the biological, ecological, and biochemical attributes of Trichoderma sp., this study examined the mechanisms associated with efficacy in bioconversion processes and waste remediation. METHODS: A survey method was used to determine sampling locations, and purposive sampling was utilized in the field. Furthermore, several stages were undertaken including isolation, identification, as well as testing of morphology and potential in vitro. FINDINGS: The results showed that the growth characteristics of Trichoderma sp. in filling a petri dish spanned approximately five days, forming colonies with a dark green hue. Microscopically, the isolates consisted of conidiophores, phialides, and conidia. Meanwhile, in vitro potential was assessed through cellulolytic and lignocellulolytic assays, with each isolate demonstrating varying capabilities in breaking down cellulose and lignocellulose. The highest cellulase activity (3.55 units per gram) was observed in enzyme starter granules treated with air drying. The highest viability per gram was found in spore inoculum (17.0 x 107) with air drying treatment. The greatest reduction in weight of oil palm EFB waste (65.3 percent) was achieved through the application of Trichoderma sp. enzyme starter granules with air drying treatment. Furthermore, eight isolates demonstrated cellulolytic and ligninolytic potential. Isolates sourced from soil had rapid growth on starter and baglog mediums, indicating potential for subsequent field applications as a biodegradation agent for organic waste. CONCLUSION: Based on the macroscopic (shape and color of mycelium) and microscopic characteristics (mycelium form), a total of eight Trichoderma sp. isolates were obtained. During the potential test, it was observed each isolate had different cellulolytic and ligninolytic activities. This study provided valuable insights into the diversity and enzymatic potential of Trichoderma sp. fungi, underscoring the importance of selecting suitable strains and optimizing cultivation conditions for various biotechnological applications. By exploring cellulolytic and ligninolytic capabilities, the results contributed to the development of more efficient and sustainable strategies for organic waste management and bioconversion. In general, this study represented a significant milestone in the quest for sustainable waste management solutions in agriculture, offering a promising pathway towards mitigating environmental impact and promoting the long-term sustainability of oil palm cultivation. [ABSTRACT FROM AUTHOR]

Fungal traits can provide a mechanistic understanding of how wood‐inhabiting fungi interact with their environment and how that influences community assembly in deadwood. However, fungal trait exploration is relatively new and almost no studies measure fungal traits in their environment.In this study we tested species‐ and trait‐environment relationships in reproducing fungal communities inhabiting 571 Norway spruce (Picea abies) logs in 55 isolated forest patches (0.1–9.9 ha) of different naturalness types, located in Northern boreal Sweden. The studied patches were (1) semi‐natural set‐aside patches within highly managed landscapes, or (2) old‐growth natural patches located in an unmanaged landscape. We tested species and trait relationships to deadwood substrate and forest patch variables. We measured mean fruit body size and density for each of the 19 species within communities.Traits assembled in relation to log decay stage and forest patch naturalness, illustrating the important role of deterministic environmental filtering in shaping reproducing wood‐inhabiting fungal communities. Early decay stage communities had larger, less dense, annual fruiting bodies of half‐resupinate type and were more often white‐rot fungi. Species rich mid‐decay stage communities had mixed trait assemblages with more long lived perennial fruit bodies of intermediate size, and both brown‐ and white‐rot fungi equally represented. Finally, late decay stage communities had smaller, denser and perennial fruit bodies, more often of the brown‐rot type.The relationships between the studied traits and decay stages were similar in both set‐aside and natural patches. However, set‐aside semi‐natural patches in highly managed landscapes more frequently supported species with smaller, perennial and resupinate fruit bodies compared to natural patches in an unmanaged landscape.Synthesis. We found that log decay stage was the primary driver of fungal community assembly of species and traits in isolated forest patches. Our results suggest that decay stage filters four reproduction traits (fruit body density, size, lifespan and type) and one resource‐use trait (white or brown rot). Our results highlights, for the first time, that communities with diverse fungal reproductive traits are maintained foremost across all deadwood decay stages under different forest naturalness conditions. Read the free Plain Language Summary for this article on the Journal blog. [ABSTRACT FROM AUTHOR]

Akahoya is a volcanic soil rich in alumina, primarily deposited in Kyushu, Japan. We have found that Akahoya adsorbs bacteria in the water surrounding cattle grazing areas, suggesting a potential for environmental purification. This study investigated the spectrum of microorganisms adsorbed by Akahoya using a column filled with Akahoya through which a suspension of microorganisms was passed. Shirasu soil, another volcanic soil with a different chemical composition, was used as a control. Akahoya effectively adsorbed a diverse range of microorganisms including Escherichia coli, Campylobacter jejuni, Vibrio parahaemolyticus, Salmonella Enteritidis, Staphylococcus aureus, Clostridium perfringens, spores of Bacillus subtilis and Bacillus anthracis, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), murine norovirus, and avian influenza virus (H3N2), whereas Shirasu soil did not adsorb any of the organisms examined. Moreover, bacteria naturally present in river water, such as aerobic bacteria, total coliforms, and Enterobacteriaceae as indicators of river contamination, as well as E. coli added artificially to sterilized river water, were reduced to below the detection limit (<1 CFU/mL) after being passed through Akahoya. Additionally, the number of viable E. coli continued to decrease after contact with Akahoya for 1 month, suggesting bactericidal effects. Notably, the adsorption of E. coli to Akahoya was influenced by the concentration of phosphate and the pH of the suspension due to the interaction between the surface phosphorylation of organisms and Al2O3, the major chemical component of Akahoya. The present results demonstrate the remarkable ability of Akahoya to remove phosphate and microbes, suggesting that Akahoya could be used for water purification processes. [ABSTRACT FROM AUTHOR]

BACKGROUND AND OBJECTIVES: Trichoderma species (Trichoderma sp.) is commonly found in nature, particularly in soil and roots, often thriving in plants rich in cellulose such as oil palm. Therefore, this study aimed to characterize Trichoderma sp. in each substrate as well as to assess cellulolytic and ligninolytic potential in vitro using a specific medium. Characterization and utilization of the plant were examined to efficiently manage empty fruit bunch (EFB) waste in Indonesian oil palm plantations. By exploring the biological, ecological, and biochemical attributes of Trichoderma sp., this study examined the mechanisms associated with efficacy in bioconversion processes and waste remediation.METHODS: A survey method was used to determine sampling locations, and purposive sampling was utilized in the field. Furthermore, several stages were undertaken including isolation, identification, as well as testing of morphology and potential in vitro.RESULTS: The results showed that the growth characteristics of Trichoderma sp. in filling a petri dish spanned approximately five days, forming colonies with a dark green hue. Microscopically, the isolates consisted of conidiophores, phialides, and conidia. Meanwhile, in vitro potential was assessed through cellulolytic and lignocellulolytic assays, with each isolate demonstrating varying capabilities in breaking down cellulose and lignocellulose. The highest cellulase activity (3.55 units per gram) was observed in enzyme starter granules treated with air drying. The highest viability per gram was found in spore inoculum (17.0 x 107) with air drying treatment. The greatest reduction in weight of oil palm EFB waste (65.3 percent) was achieved through the application of Trichoderma sp. enzyme starter granules with air drying treatment. Furthermore, eight isolates demonstrated cellulolytic and ligninolytic potential. Isolates sourced from soil had rapid growth on starter and baglog mediums, indicating potential for subsequent field applications as a biodegradation agent for organic waste.CONCLUSION: Based on the macroscopic (shape and color of mycelium) and microscopic characteristics (mycelium form), a total of eight Trichoderma sp. isolates were obtained. During the potential test, it was observed each isolate had different cellulolytic and ligninolytic activities. This study provided valuable insights into the diversity and enzymatic potential of Trichoderma sp. fungi, underscoring the importance of selecting suitable strains and optimizing cultivation conditions for various biotechnological applications. By exploring cellulolytic and ligninolytic capabilities, the results contributed to the development of more efficient and sustainable strategies for organic waste management and bioconversion. In general, this study represented a significant milestone in the quest for sustainable waste management solutions in agriculture, offering a promising pathway towards mitigating environmental impact and promoting the long-term sustainability of oil palm cultivation.

Conidial production is a critical factor in testing pathogenicity and studying the physiology and ecology of fungal pathogens. Therefore, selecting an appropriate condition and medium for consistent conidia production is essential. In this study, we investigated light conditions and suitable medium conditions using the slide culture method to establish optimal conditions for continuous spore acquisition of Bipolaris oryzae. Primarily, we observed conidial production using two B. oryzae isolates, CM23-042 and 23CM10, under two different light conditions: (1) consistent near-ultraviolet (NUV) with fluorescent light, and (2) a 12-hr shift of the NUV-dark cycle. Secondly, we examined conidial formation under seven different media on potato dextrose agar (PDA), V8-Juice agar, minimal medium (MM), sucrose-proline agar (SPA), rabbit food agar (RFA), rice bran agar (RBA), and rice leaf agar (RLA). Under consistent NUV light with fluorescent conditions, conidia were induced in both isolates, whereas conidia were not produced under other conditions after 7 days post-inoculation (dpi). Moreover, B. oryzae isolate CM23-042 produced the highest number of conidia in MM, while isolate 23CM10 yielded the highest number of conidia in PDA after 7 dpi. In summary, our data demonstrated that the consistent NUV light with fluorescent conditions were most conducive for conidia induction in B. oryzae. The selection of a medium for conidiation may vary depending on the B. oryzae isolates, but using MM and PDA or SPA and RFA medium could be effective for spore induction. These findings will contribute to improving conidiation according to the characteristics of collected isolates of B. oryzae.

BACKGROUND: Aphid infestation adversely affects the yield and quality of crops. Rapid reproduction and insecticidal resistance have made controlling aphids in the field challenging. Therefore, the present study investigated the insecticidal property of Penicillium oxalicum (QLhf‐1) and its mechanism of action against aphids, Hyalopterus arundimis Fabricius. RESULTS: Bioassay revealed that the control efficacy of the spores against aphids (86.30% and 89.05% on the third day and fifth day after infection, respectively) were higher than other components, such as the mycelium. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) showed that QLhf‐1 invaded the aphid cuticle through spores and used the aphid tissues as a nutrient source for growth and reproduction, causing stiffness and atrophy and a final death. Three extracellular enzymes, lipase, protease, and chitinase had a synergistic effect with spores, and they acted together to complete the infection process by degrading the aphid body wall and accelerating the infection process. CONCLUSION: The newly discovered endophytic penicillin strain P. oxalicum 'QLhf‐1' can effectively kill aphids. The results provided strong evidence for the biological control of aphids, and lay a foundation for the development and utilization of QLhf‐1. © 2024 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

This study aimed to investigate the inactivation effect of combined TS (thermosonication) and PS (potassium sorbate) treatments on Bacillus subtilis spores. The inactivation effect and potential mechanisms were examined using plate counts, OD600 values, nucleic acid leakage, DPA (dipicolinic acid) leakage, flow cytometry, and FTIR (Fourier transform infrared spectroscopy). The results showed that, after TS + PS treatments, the integrity of the inner membrane was lost, the permeability of the inner membrane to water molecules was increased, and the intraspore substances leaked. Furthermore, the OD600 value was reduced, indicating that the spore core hydration was enhanced. Spores proportion with damaged inner membrane was significantly increased to 66%, the ordered secondary structure of the protein was changed into a disordered structure and nucleic acid was fragmented after TS + PS treatment. The results indicated that the combined TS and PS treatments may be a useful method for inactivating bacterial spores in food processing and sterilization. [ABSTRACT FROM AUTHOR]

This study investigated the effects of low-pressure cold plasma on the inactivation of Bacillus cereus vegetative cells and spores in an inert matrix (borosilicate glass slide) and in rice grains, using oxygen as ionization gas. Greater reductions in B. cereus counts were observed in vegetative cells rather than spores. The experimental data obtained show that both the power of the plasma treatment and the matrix proved to be determining factors in the inactivation of both the spores and vegetative cells of B. cereus. To characterize the inactivation of B. cereus, experimental data were accurately fitted to the Weibull model. A significant decrease in parameter "a", representing resistance to treatment, was confirmed with treatment intensification. Furthermore, significant differences in the "a" value were observed between spores in inert and food matrices, suggesting the additional protective role of the food matrix for B. cereus spores. These results demonstrate the importance of considering matrix effects in plasma treatment to ensure the effective inactivation of pathogenic microorganisms, particularly in foods with low water activity, such as rice. This approach contributes to mitigating the impact of foodborne illnesses caused by pathogenic microorganisms. [ABSTRACT FROM AUTHOR]

Most Mucoromycota fungi form zygospores as sexual reproductive structures. When two colonies of compatible strains meet, zygospores are formed in the area where the colonies meet. The structure and development of zygospores have been studied for a long time by light microscopy and electron microscopy. This study is the first time-lapse report on the dynamic movements of sexual and asexual reproductive processes by live imaging in Gilbertella persicaria (Choanephoraceae, Mucorales). Our live imaging analysis indicated the formation of zygospores begin immediately after two aerial hyphae contact whether at the tip or middle of the hyphae. The early-stage zygospores elongated from the contact site with a rate of 1.2-1.7 µm/s and reach < 200 µm in 2-3 h. Following maturation of zygospores, from progametangia to gametangia and maturation stage, took a few hours, in total 5 to 6 h after the first contact of two hyphae. When a zygospore was formed near the tip of hypha in contact with the partner hypha, the hyphal growth ceased. When zygospore was formed behind the tip of the hypha, the hyphal growth continued without slowing down. This study provides quantitative spatio-temporal information on the dynamics of zygospore formation. [ABSTRACT FROM AUTHOR]

Aim Ohmic heating (OH) (i.e. heating by electric field) more effectively kills bacterial spores than traditional wet heating, yet its mechanism remains poorly understood. This study investigates the accelerated spore inactivation mechanism using genetically modified spores. Methods and results We investigated the effects of OH and conventional heating (CH) on various genetically modified strains of Bacillus subtilis : isogenic PS533 (wild type_1), PS578 [lacking spores' α/β-type small acid-soluble proteins (SASP)], PS2318 (lacking recA , encoding a DNA repair protein), isogenic PS4461 (wild type_2), and PS4462 (having the 2Duf protein in spores, which increases spore wet heat resistance and decreases spore inner membrane fluidity). Removal of SASP brought the inactivation profiles of OH and CH closer, suggesting the interaction of these proteins with the field. However, the reemergence of a difference between CH and OH killing for SASP-deficient spores at the highest tested field strength suggested there is also interaction of the field with another spore core component. Additionally, RecA-deficient spores yielded results like those with the wild-type spores for CH, while the OH resistance of this mutant increased at the lower tested temperatures, implying that RecA or DNA are a possible additional target for the electric field. Addition of the 2Duf protein markedly increased spore resistance both to CH and OH, although some acceleration of killing was observed with OH at 50 V/cm. Conclusions In summary, both membrane fluidity and interaction of the spore core proteins with electric field are key factors in enhanced spore killing with electric field-heat combinations. [ABSTRACT FROM AUTHOR]

Summary: Global change is reshaping Earth's biodiversity, but the changing distributions of nonpathogenic fungi remain largely undocumented, as do mechanisms enabling invasions. The ectomycorrhizal Amanita phalloides is native to Europe and invasive in North America. Using population genetics and genomics, we sought to describe the life history traits of this successfully invading symbiotic fungus.To test whether death caps spread underground using hyphae, or aboveground using sexual spores, we mapped and genotyped mushrooms from European and US sites. Larger genetic individuals (genets) would suggest spread mediated by vegetative growth, while many small genets would suggest dispersal mediated by spores. To test whether genets are ephemeral or persistent, we also sampled from populations over time.At nearly every site and across all time points, mushrooms resolve into small genets. Individuals frequently establish from sexual spores. But at one Californian site, a single individual measuring nearly 10 m across dominated. At two Californian sites, the same genetic individuals were discovered in 2004, 2014, and 2015, suggesting single individuals (both large and small) can reproduce repeatedly over relatively long timescales.A flexible life history strategy combining both mycelial growth and spore dispersal appears to underpin the invasion of this deadly perennial ectomycorrhizal fungus. [ABSTRACT FROM AUTHOR]

Clostridium sporogenes is an anaerobic spore-forming bacterium genetically related to Clostridium botulinum but lacks toxin genes. The sporulation mechanism and spore structures of anaerobic bacteria, including C. sporogenes, have not been comprehensively analyzed. Based on 16S rRNA gene analysis, it has been determined that C. sporogenes NBRC 14293 belongs to C. botulinum Group I. Moreover, SpoIVA is highly conserved in Bacillus and Clostridium species. Therefore, the aim of the present study is to investigate the mechanism of spore formation in C. sporogenes by performing a functional analysis of spoIVA encoding SpoIVA, a protein involved in the early development of the spore coat and cortex in Bacillus subtilis. Inactivation of spoIVA in C. sporogenes resulted in the loss of resistance of sporulating cells to lysozyme and heat treatments. Phase-contrast microscopy indicated that the inactivation of spoIVA caused the development of abnormal forespores and production of only a few immature spores. In the spoIVA mutant, abnormal swirl structures were detected in the mother cell using both phase-contrast and transmission electron microscopy. These swirls were stained with auramine O, pararosaniline hydrochloride, and 2-(4-aminophenyl)benzothiazole to examine the surface of mature spores of the wild-type strain. We found that the spore coat and exosporium proteins were misassembled and that they accumulated in the mother cells of the mutant. The results of this study indicate that SpoIVA is a spore morphogenetic protein, providing novel insights into spore morphogenesis in C. sporogenes. [ABSTRACT FROM AUTHOR]

Diplazium simplicivenium Holtt. a species of fern in Peninsular Malaysia. This study reports an efficient method for D. simplicivenium spore sterilisation and the effect of plant growth regulators (PGRs) via green globular bodies (GGB). Sterilisation with 0.1% mercuric chloride effectively allowed spore germination. The result showed that the culture media supplemented with 0.5 mg/L gibberellin positively affects the weight of GGB and the number of shoots with significant differences (ANOVA, p < 0.05). The soaking technique established in this study for spore sterilisation is an efficient approach, and the optimal plant and concentration of plant hormones were identified. This procedure can be applied to other indigenous ferns and closely similar species. [ABSTRACT FROM AUTHOR]

Nosema bombycis (Nb) is a pathogen causing pebrine in sericulture. Ultraviolet (UV) light exposure is a common physical disinfection method, but the mechanisms underlying UV‐based disinfection have only been studied at the population level. In this study, changes in and germination of UV‐irradiated spores were observed using Raman tweezers and phase‐contrast imaging to evaluate the effects of UV radiation on Nb spores at the single‐cell level. We found that irradiation caused the complete leakage of trehalose from individual spores. We also found that more spores leaked as the UV dose increased. There was no significant loss of intracellular biomacromolecules and no marked changes in the peaks associated with protein secondary structures. Low‐dose radiation promoted spore germination and high‐dose radiation decreased the germination rate, while the germination time did not undergo significant alterations. These results suggest that UV radiation disrupts the permeability of the inner membrane and alters the spore wall, thereby affecting the ability of the spore to sense and respond to extracellular stimuli, which further triggers germination and reduces or stops spore germination. This study provides new insights into the molecular mechanisms underlying conventional disinfection measures on microsporidian spores. [ABSTRACT FROM AUTHOR]

Upon starvation, rod‐shaped Myxococcus xanthus bacteria form mounds and then differentiate into round, stress‐resistant spores. Little is known about the regulation of late‐acting operons important for spore formation. C‐signaling has been proposed to activate FruA, which binds DNA cooperatively with MrpC to stimulate transcription of developmental genes. We report that this model can explain regulation of the fadIJ operon involved in spore metabolism, but not that of the spore coat biogenesis operons exoA‐I, exoL‐P, and nfsA‐H. Rather, a mutation in fruA increased the transcript levels from these operons early in development, suggesting negative regulation by FruA, and a mutation in mrpC affected transcript levels from each operon differently. FruA bound to all four promoter regions in vitro, but strikingly each promoter region was unique in terms of whether or not MrpC and/or the DNA‐binding domain of Nla6 bound, and in terms of cooperative binding. Furthermore, the DevI component of a CRISPR‐Cas system is a negative regulator of all four operons, based on transcript measurements. Our results demonstrate complex regulation of sporulation genes by three transcription factors and a CRISPR‐Cas component, which we propose produces spores suited to withstand starvation and environmental insults. [ABSTRACT FROM AUTHOR]

Bacillus licheniformis formulations are effective for environmental remediation, gut microbiota modulation, and soil improvement. An adequate spore quantity is crucial for the activity of B. licheniformis formulations. This study investigated the synergistic effects of carbon/nitrogen source consumption and concentration on B. licheniformis BF‐002 cultivation, with the aim of developing an automatic co‐feeding strategy to enhance spore production. Initial glucose (10 g/L) and amino nitrogen (1.5 g/L) concentrations promote cell growth, followed by reduced glucose (2.0 g/L) and amino nitrogen (0.5 g/L) concentrations for sustained spore generation. The spore quantity reached 2.59 × 1010 CFU/mL. An automatic co‐feeding strategy was developed and implemented in 5 and 50 L cultivations, resulting in spore quantities of 2.35 × 1010 and 2.86 × 1010 CFU/mL, respectively, improving by 6.81% and 30.00% compared to that with a fixed glucose concentration (10.0 g/L). The culture broth obtained at both the 5 and 50 L scales was spray‐dried, resulting in bacterial powder with cell viability rates of 85.94% and 82.68%, respectively. Even after exposure to harsh conditions involving high temperature and humidity, cell viability remained at 72.80% and 69.89%, respectively. Employing the automatic co‐feeding strategy increased the transcription levels of the spore formation‐related genes spo0A, spoIIGA, bofA, and spoIV by 7.42%, 8.46%, 8.87%, and 9.79%, respectively. The proposed strategy effectively promoted Bacillus growth and spore formation, thereby enhancing the quality of B. licheniformis formulations. [ABSTRACT FROM AUTHOR]

Abstract Persistent diarrhea is a severe gastroenteric disease with relatively high risk of pediatric mortality in developing countries. We conducted a randomized, double-blind, controlled clinical trial to evaluate the efficacy of liquid-form Bacillus clausii spore probiotics (LiveSpo CLAUSY; 2 billion CFU/5 mL ampoule) at high dosages of 4–6 ampoules a day in supporting treatment of children with persistent diarrhea. Our findings showed that B. clausii spores significantly improved treatment outcomes, resulting in a 2-day shorter recovery period (p

Fungi, including Rhizopus sp., are food sources that commonly contain high nucleic acid levels. Therefore, the nucleic acid content must be reduced to achieve health standard requirements. This study aimed to isolate, identify, and produce Rhizopus sp. mycelium containing low nucleic acid. The Rhizopus spp. were isolated from tempeh collected from 12 different areas in Indonesia. Fungal identification was conducted based on morphological characteristics. The fungal isolates were selected based on mycelial growth and spore production on PDA. Biomass production of mycelium was carried out in potato extract and soybean extract media obtained from 200 g/L and 333.3 g/L, respectively. In each medium, 6 sugar levels were added, namely 0, 2, 3, 4, 5, and 6 g/L. Mycelium nucleic acid content reduction was achieved by heat treatment at 50°C and 60°C for 15 minutes and measured by a spectrophotometer at 260 nm. Fifty-eight isolates that were identified into 3 species were obtained in this experiment: R. oryzae, R. stolonifera, and R. microsporus. R. Microsporus had higher mycelium biomass and lower spore number than the other species. R. Microsporus produced a higher mycelium biomass in the soybean extract medium with 5 g/L additional sugar. The nucleic acid content of the 50°C heat-treated mycelium was 1.82% and 1.73% at 65°C. These values fulfilled the standard of mycelial nucleic acid content permitted in food by the USDA. [ABSTRACT FROM AUTHOR]

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Persistent diarrhea is a severe gastroenteric disease with relatively high risk of pediatric mortality in developing countries. We conducted a randomized, double-blind, controlled clinical trial to evaluate the efficacy of liquid-form Bacillus clausii spore probiotics (LiveSpo CLAUSY; 2 billion CFU/5 mL ampoule) at high dosages of 4–6 ampoules a day in supporting treatment of children with persistent diarrhea. Our findings showed that B. clausii spores significantly improved treatment outcomes, resulting in a 2-day shorter recovery period (p < 0.05) and a 1.5–1.6 folds greater efficacy in reducing diarrhea symptoms, such as high frequency of bowel movement of ≥ 3 stools a day, presence of fecal mucus, and diapered infant stool scale types 4-5B. LiveSpo CLAUSY supportive treatment achieved 3 days (p < 0.0001) faster recovery from diarrhea disease, with 1.6-fold improved treatment efficacy. At day 5 of treatment, a significant decrease in blood levels of pro-inflammatory cytokines TNF-α, IL-17, and IL-23 by 3.24% (p = 0.0409), 29.76% (p = 0.0001), and 10.87% (p = 0.0036), respectively, was observed in the Clausy group. Simultaneously, there was a significant 37.97% decrease (p = 0.0326) in the excreted IgA in stool at day 5 in the Clausy group. Overall, the clinical study demonstrates the efficacy of B. clausii spores (LiveSpo CLAUSY) as an effective symptomatic treatment and immunomodulatory agent for persistent diarrhea in children. Trial registration: NCT05812820. [ABSTRACT FROM AUTHOR]

Defence theories provide predictions about trade‐offs in the allocation of resources to defence and growth. However, very little is known about how pressure from herbivores influences the allocation of resources during reproduction.Two common peatland bryophyte species, Sphagnum angustifolium and S. capillifolium, were chosen as study species. Vegetative and reproductive shoots of both Sphagnum species were subjected to treatments with and without herbivores in a lab experiment. After 4 weeks of exposure to herbivores in a growth chamber, we measured biomass production, net photosynthesis rate, defence traits (phenolics in leachate and phenolics in extract), nonstructural carbohydrates (soluble sugar and starch), and reproductive traits (capsule number, weight and diameter, and spore germination) of both Sphagnum species.Reproductive shoots had higher constitutive defence than vegetative shoots in S. angustifolium, and a similar pattern was observed in S. capillifolium. With herbivory, reproductive shoots showed stronger induced defence (released more phenolics) than vegetative shoots in S. capillifolium, but not in S. angustifolium. Herbivory had no effect on capsule number, weight, or diameter, but reduced spore germination percentage by more than half in both species.Our study highlights the hidden effects of herbivory on reproduction of Sphagnum and indicates the presence of maternal effects in bryophytes. Ecologists will benefit from examining both quality‐ and quantity‐based traits when attempting to estimate the herbivory effect on plant fitness. [ABSTRACT FROM AUTHOR]

SUMMARY: The establishment of moss spores is considered a milestone in plant evolution. They harbor protein networks underpinning desiccation tolerance and accumulation of storage compounds that can be found already in algae and that are also utilized in seeds and pollen. Furthermore, germinating spores must produce proteins that drive the transition through heterotrophic growth to the autotrophic plant. To get insight into the plasticity of this proteome, we investigated it at five timepoints of moss (Physcomitrium patens) spore germination and in protonemata and gametophores. The comparison to previously published Arabidopsis proteome data of seedling establishment showed that not only the proteomes of spores and seeds are functionally related, but also the proteomes of germinating spores and young seedlings. We observed similarities with regard to desiccation tolerance, lipid droplet proteome composition, control of dormancy, and β‐oxidation and the glyoxylate cycle. However, there were also striking differences. For example, spores lacked any obvious storage proteins. Furthermore, we did not detect homologs to the main triacylglycerol lipase in Arabidopsis seeds, SUGAR DEPENDENT1. Instead, we discovered a triacylglycerol lipase of the oil body lipase family and a lipoxygenase as being the overall most abundant proteins in spores. This finding indicates an alternative pathway for triacylglycerol degradation via oxylipin intermediates in the moss. The comparison of spores to Nicotiana tabacum pollen indicated similarities for example in regards to resistance to desiccation and hypoxia, but the overall developmental pattern did not align as in the case of seedling establishment and spore germination. [ABSTRACT FROM AUTHOR]

Wild-type Aspergillus nidulans asexual spores (conidia) are green due to a pigment that protects the spores against ultraviolet light. The pigment is produced by a biosynthetic pathway, the genes of which are dispersed in the genome. The backbone molecule of the pigment is a polyketide synthesized by a polyketide synthase encoded by the wA gene. If wA is not functional, the conidia are white. The polyketide is modified by a laccase encoded by the yA gene and inactivation of yA in an otherwise wild-type background results in yellow spores. Additional spore color mutations have been isolated and mapped to a locus genetically, but the genes that correspond to these loci have not been determined. Spore color markers have been useful historically, and they remain valuable in the molecular genetics era. One can determine if a transforming fragment has been successfully integrated at the wA or yA locus by simply looking at the color of transformant conidia. The genes of the potentially useful color loci chaA (chartreuse conidia) and fwA (fawn conidia) have not been identified previously. We chose a set of candidate genes for each locus by comparing the assembled genome with the genetic map. By systematically deleting these candidate genes, we identified a cytochrome P450 gene (AN10028) corresponding to chaA. Deletions of this gene result in chartreuse conidia and chartreuse mutations can be complemented in trans by a functional copy of this gene. With fwA, we found that the existing fawn mutation, fwA1, is a deletion of 2241 base pairs that inactivates three genes. By deleting each of these genes, we determined that fwA is AN1088, an EthD domain protein. Deletion of AN1088 results in fawn conidia as expected. Neither deletion of chaA nor fwA restricts growth and both should be valuable target loci for transformations. Combinations of deletions have allowed us to investigate the epistasis relationships of wA, yA, chaA and fwA. [ABSTRACT FROM AUTHOR]

Outbreaks of environmentally transmitted parasites require that susceptible hosts encounter transmission stages in the environment and become infected, but we also know that transmission stages can be in the environment without triggering disease outbreaks. One challenge in understanding the relationship between environmental transmission stages and disease outbreaks is that the distribution and abundance of transmission stages outside of their hosts have been difficult to quantify. Thus, we have limited data about how changes in transmission stage abundance influence disease dynamics; moreover, we do not know whether the relationship between transmission stages and outbreaks differs among parasite species. We used digital PCR to quantify the environmental transmission stages of five parasites in six lakes in southeastern Michigan every 2 weeks from June to November 2021. At the same time, we quantified infection prevalence in hosts and host density. Our study focused on eight zooplankton host species (Daphnia spp. and Ceriodaphnia dubia) and five of their parasites from diverse taxonomic groups (bacteria, yeast, microsporidia, and oomycete) with different infection mechanisms. We found that parasite transmission stage concentration increased prior to disease outbreaks for all parasites. However, parasites differed significantly in the relative timing of peaks in transmission stage concentration and infection outbreaks. The "continuous shedder" parasites had transmission stage peaks at the same time as or slightly after the outbreak peaks. In contrast, parasites relying on host death for transmission ("obligate killers") had transmission stage peaks before outbreak peaks. For most parasites, lakes with outbreaks had higher spore concentrations than those without outbreaks, especially once an outbreak began; the exception was for a parasite, Pasteuria ramosa, with very strong genotypic specificity of infection. Overall, our results show that disease outbreaks are tightly linked to transmission stage concentration; outbreaks were preceded by increases in transmission stage concentration in the environment and then were fueled by the production of more transmission stages during the outbreak itself, with concentrations decreasing to pre‐outbreak levels as outbreaks waned. Thus, tracking transmission stages in the environment improves our understanding of the drivers of disease outbreaks and reveals how parasite traits may affect these dynamics. [ABSTRACT FROM AUTHOR]

Different host species associate with distinct gut microbes in mammals, a pattern sometimes referred to as phylosymbiosis. However, the processes shaping this host specificity are not well understood. One model proposes that barriers to microbial transmission promote specificity by limiting microbial dispersal between hosts. This model predicts that specificity levels measured across microbes is correlated to transmission mode (vertical vs. horizontal) and individual dispersal traits. Here, we leverage two large publicly available gut microbiota data sets (1490 samples from 195 host species) to test this prediction. We found that host specificity varies widely across bacteria (i.e., there are generalist and specialist bacteria) and depends on transmission mode and dispersal ability. Horizontally‐like transmitted bacteria equipped with traits that facilitate switches between host (e.g., tolerance to oxygen) were found to be less specific (more generalist) than microbes without those traits, for example, vertically‐like inherited bacteria that are intolerant to oxygen. Altogether, our findings are compatible with a model in which limited microbial dispersal abilities foster host specificity. see also the Perspective by Elizabeth K. Mallott [ABSTRACT FROM AUTHOR]

Antimicrobial coatings can inhibit the transmission of infectious diseases when they provide a quick kill that is achieved long after the coating application. Here, we describe the fabrication and testing of a glass coating containing Ag2O microparticles that was prepared from sodium silicate at room temperature. The half-lives of both methicillin-resistant Staphylococcus aureus (MRSA) and Pseudomonas aeruginosa on this coating are only 2–4 min. The half-life of Clostridioides difficile spores is about 9–12 min, which is extremely short for a spore. Additional tests on MRSA demonstrate that the coating retains its antimicrobial activity after abrasion and that an increased loading of Ag2O leads to a shorter half-life. This coating combines the properties of optical transparency, robustness, fast kill, and room temperature preparation that are highly desirable for an antimicrobial coating. [ABSTRACT FROM AUTHOR]

The Bacillus licheniformis formulation is effective in environmental remediation, gut microbiota modulation, and soil improvement. Adequate spore quantity is crucial for activity of B. licheniformis formulations. This study aimed to enhance B. licheniformis BF‐002 sporulation by optimizing nitrogen source feeding. In the initial four manual feeding strategies, continuous feeding based on exhaust CO2 resulted in the highest cell and spore quantities (1.44 × 1010 and 6.12 × 109 cfu/mL). Python‐based automatic feeding, based on online exhaust CO2 detection, was developed and implemented in 5 and 50 L cultivations. Compared to manual feeding, cell and spore quantities increased by 31.25% and 97.7%, respectively. Substituting costly peptone (fish) with NH4Cl reduced spore quantity by 8.46% and 9.25% in 5 and 50 L cultivations, while cutting nitrogen source cost by 87.08% and 91.39%. Employing exhaust CO2 concentration for automatic nitrogen supplementation effectively promotes Bacillus growth and spore formation. [ABSTRACT FROM AUTHOR]

The entomopathogenic bacterium,Bacillus thuringiensis, is a gram-positive and sporeforming bacterium, and a large number of its subspecies have been identified and introduced. The insect immune responses activate after ingesting Bt or its toxin proteins. This research aimed to investigate the effect of temperature and three subspecies including B. thuringiensis subspecies thuringiensis (Btt), B. thuringiensis subspecies aizawai (Bta), and B. thuringiensis subspecies galleriae (Btg) on nodule formation and some biological parameters of the moth Ephestia kuehniella Zeller (Lepidoptera: Pyralidae). A concentration of 109 spore/ml was used to contaminate the larval diet. This experiment was performed at three different temperatures (20, 25, and 30 ºC), relative humidity of 55±5%, and a photoperiod of 16:8 (L: D). The highest number of nodules was significantly observed in Bta and Btg treatments at 30 ºC and the lowest number of nodules was observed in the control. There was no significant difference in the time until pupation at any temperature among the three subspecies. However, a significant difference was observed between different temperatures in each subspecies. Therefore, this duration in the control was significantly affected by temperature. The highest amount of pupa production was related to the temperatures of 20 and 25 ºC in subspecies Bta and the control that had no significant difference. The number of adults obtained in the Bta treatment was not affected by the temperature, similar to the control. Since the temperature did not affect the number of nodules in the control, it is concluded that increasing the temperature by affecting the Bt increased the number of the nodules formed in the surviving larvae and also, the subspecies kind of the bacterium had a significant effect on it. [ABSTRACT FROM AUTHOR]

The Upper Red Formation has extensive outcrops in the southern and western parts of the Zanjan province, northwestern Iran. Here, we studied a sequence of lowermost part of this formation near Mehr)Abad village, northwestern Zanjan. Lithostratigraphy, sedimentology and ichnology of the URF have been studied in recent decades but palynology of this formation has not been investigated. This article is a preliminary report of miospores. The palynofloras comprise thirty species including three algae spores (in three genera), seven fern species (in seven genera), various type of gymnosperm (thirteen species designated to nine genera), and angiosperm pollen species (seven species designated to six genera); for example, Botryococcus sp., Closteritetrapidites magnus, and Diagonalites diagonalis of algal spores; Echinatisporis muelleri, Magnastriatites sp. cf. M. grandiosus, and Polyapodiaceoisporites potoniei of fern; Cathayapollis scheuringii, Cedripites sp., Ephedripites tertiarius, Pinuspollenites spp., Cupressacites spp., Tsugapollenites spp. of gymnosperm, and Acidanthera brevicollis, Calliandra spp., Fagopsis longifolia, Monoporopollenites sp., and Retitricolporites sp. of angiosperm evidenced herein. Moreover, botanical affinity of miospores considered. Therefore, Botryococcaceae/ Dictyosphaeriaceae, Closteriaceae, Zygnemataceae (algae); Marattiaceae, Pteridaceae, Polypodiaceae (fern); Cupressaceae, Ephedraceae, Pinaceae (gymnosperm), and Fagaceae, Fabaceae, Iridaceae, and Poaceae (angiosperm) identified. [ABSTRACT FROM AUTHOR]

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Summary: Alicyclobacillus acidoterrestris is a typical endospore‐forming microorganism, whose spores are able to germinate in Not From Concentrate juice causing its spoilage. In this work, dielectric barrier discharge atmospheric cold plasma (DBD‐ACP) at the voltage of 30 kV was used to inactivate Alicyclobacillus acidoterrestris spores in NFC juice (2–8 min). The results showed spores reduced nearly 3‐log CFU mL−1 after 8 min treatment, and the morphology of spores were severely disrupted, causing the release of their contents. Furthermore, proteomic analysis showed totals of 122 and 170 different expression proteins were detected in group C (control)/Ct1 (30 kV, 4 min) and C/Ct2 (30 kV, 8 min), respectively, indicating that metabolic activities of spores including amino acid and energy metabolic, protein biosynthesis, DNA replication and spore germination are inhibited. This study confirms the inactivation of Alicyclobacillus acidoterrestris spores by DBD‐ACP and provides some new perspectives on the inactivation mechanisms of spores by DBD‐ACP. [ABSTRACT FROM AUTHOR]

Clostridium perfringens is one of the major foodborne pathogens in humans and animals. With the prevalence of antibiotic-resistant C. perfringens strains, bacteriophages and their endolysins have received considerable attention as promising alternatives to antibiotics. In this study, C. perfringens phage CPD2 was isolated from retail chicken samples. CPD2 belongs to the Podoviridae family and exhibits remarkable thermostability. While CPD2 has narrow host specificity, its endolysin LysCPD2 showed a broader lytic range, killing not only C. perfringens strains but other Gram-positive bacteria, such as B. cereus and B. subtilis. In addition, due to its exceptional thermal stability, LysCPD2 showed significant antibacterial ability against germinating C. perfringens spores during the heat activation process (75 °C for 20 min). Taken together, these results indicate that both thermostable phage CPD2 and its endolysin LysCPD2 can be used as efficient antimicrobial agents to control C. perfringens during thermal processing of foods. [ABSTRACT FROM AUTHOR]

Bacterial spores are formed by cells of Clostridium, Bacillus and related genera as a response to a lack of one or more nutrients. These spores are dormant and resistant to inactivation treatments, including heat, radiation, preservatives, and high-pressure. Particularly, spores can germinate and develop in food products, resulting in the food spoilage or instances of foodborne illness. Bacillus subtilis spores are inactivated in food at high temperatures exceeding 100 ℃ during the traditional food processing. Nevertheless, high temperatures can pose a significant impact on food quality. This study aims to mitigate this temperature effect for the lower sterilization temperature. Potassium sorbate was integrated with PATS (pressure assisted thermal sterilization) into inactivate Bacillus subtilis spores. The release of important intraspore substances was established by spectrophotometry testing the OD600 (optical density at 600 nm) value, OD260 (optical density at 260 nm) value, OD280 (optical density at 280 nm) value, and DPA (2,6-pyridine dicarboxylic acid) levels. And the spore structure was examined via SEM (scanning electron microscopy), flow cytometry, FTIR (Fourier transform infrared spectroscopy), and PSD (particle size distribution analysis). The addition of potassium sorbate was improved the sporicidal effect of PATS. The surviving spores plate counting demonstrated that the initial viable spore concentration was approximately 1.5×108 CFU/mL. Treatment with 200 MPa-75 ℃ inactivated 2.63 lg CFU/mLspores, and the combined treatment of 200 MPa-75 ℃ and 2 g/L potassium sorbate inactivated 3.24 lg CFU/mLspores. The untreated spore suspensions displayed OD600, OD260, and OD280 values of 1, 0.053, and 0.046, respectively. Following a spore suspension treatment of 200 MPa-75 ℃-2 g/L potassium sorbate, the OD600 value declined by 0.413, while the OD260 and OD280 values increased to 0.401 and 0.290, respectively. It was indicated that the addition of potassium sorbate was enhanced the liberation of protein and nucleic acid in spores, leading to the reduced turbidity of spore suspensions. After treatment with 200 MPa-75 ℃, the DPA release increased by 51.31%, compared with the untreated spore suspensions. Additionally, the DPA release rate increased to 75.28% after treatment with 200 MPa-75 ℃-2 g/L potassium sorbate. This result further confirmed that the combination of PATS with potassium sorbate treatment was enhanced the permeability of the spore inner membrane, which was positively correlated with the addition of potassium sorbate and temperature. SEM images demonstrated that the addition of potassium sorbate to PATS caused significant spore damage and destruction of the cell wall, cortex and inner membrane, compared with the treatment with PATS alone. Further analysis through flow cytometry and PSD revealed that the damage on the inner membrane was worsened, while particle diameter significantly decreased, and specific surface area increased considerably after combined treatment. The FTIR disclosed the peak shift and change in intensity. The spore inner membrane phospholipids were transformed from a gel state to a liquid crystal state after PATS and potassium sorbate treatment, indicating the reduced the stability, compared with the untreated spores and PATS treatment alone. Simultaneously, the Na+ /K+ -ATPase activity registered a significant decrease, when PATS was used in the combination with potassium sorbate. This activity was used to disturb the balance of the inner membrane potential, as well as the fundamental physiological and metabolic functions. The findings reveal that there was the synergistic bactericidal impact on Bacillus subtilis spores at lower temperatures, compared with the conventional inactivated spores, when PATS was combined with potassium sorbate. The synergistic bactericidal effect was also augmented with the increase of temperature and potassium sorbate concentration. The primary mechanism for the inactivation of Bacillus subtilis spores was attributed to the damage of the permeability and structural integrity of inner membrane. These findings have practical applications to promote the food sterilization, in order to reduce the adverse impact of high temperatures on food quality. [ABSTRACT FROM AUTHOR]

Clostridioides difficile spores are considered as the major source responsible for the development of C. difficile infection (CDI), which is associated with an increased risk of death in patients and has become an important issue in infection control of nosocomial infections. Current treatment against CDI still relies on antibiotics, which also damage normal flora and increase the risk of CDI recurrence. Therefore, alternative therapies that are more effective against C. difficile bacteria and spores are urgently needed. Here, we designed an oxidation process using H2O2 containing PBS solution to generate Cl− and peroxide molecules that further process Ag and Au ions to form nanoboxes with Ag–Au peroxide coat covering Au shell and AgCl core (AgAu‐based nanoboxes). The AgAu‐based nanoboxes efficiently disrupted the membrane structure of bacteria/spores of C. difficile after 30–45 min exposure to the highly reactive Ag/Au peroxide surface of the nano structures. The Au‐enclosed AgCl provided sustained suppression of the growth of 2 × 107 pathogenic Escherichia coli for up to 19 days. In a fecal bench ex vivo test and in vivo CDI murine model, biocompatibility and therapeutic efficacy of the AuAg nanoboxes to attenuate CDI was demonstrated by restoring the gut microbiota and colon mucosal structure. The treatment successfully rescued the CDI mice from death and prevented their recurrence mediated by vancomycin treatment. The significant outcomes indicated that the new peroxide‐derived AgAu‐based nanoboxes possess great potential for future translation into clinical application as a new alternative therapeutic strategy against CDI. [ABSTRACT FROM AUTHOR]

Copyright of Biotechnologie, Agronomie, Societe et Environnement is the property of Les Presses Agronomiques de Gembloux and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

A study was conducted on the colonization and the diversity of arbuscular mycorrhizal fungi (AMF) on the roots of the Mizo Bird's eye chilli Capsicum frutescens L. The study was carried out at three home gardens within Aizawl, Mizoram during the year 2018 - 2019. The study was conducted for different stages of the plant, namely -- Juvenile stage, Fruiting stage and Senescence stage. The highest colonization of AMF was found in the roots of the plant in the juvenile stage and the lowest was found in the roots of the plant in the senescence stage. Seven AMF taxa belonging to the genera Acaulospora (3 spp.), Glomus (2 spp.), Pacispora (1 sp.) and Funneliformis (1 sp.) were found. Among these, Acaulospora was the dominant genus found at all sites, followed by Glomus. The spore density and root colonization of AMF on Mizo Bird's Eye Chilli varied significantly among the different stages of the plant. [ABSTRACT FROM AUTHOR]

Penicillium expansum, a common spoilage organism in postharvest fruits, can cause fruit decay and deterioration and endanger human health. It is of great significance to investigate the antimicrobial mechanism of the antimicrobial peptide from Paenibacillus ehimensis on P. expansum spores. The antimicrobial activity of the antimicrobial peptide against P. expansum spores was determined by using the two-fold dilution method as well as measuring the time-killing curve. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were used to evaluate the effect of the antimicrobial peptide on the ultrastructure of P. expansum spores. The effects of the antimicrobial peptide on the cell membrane and reactive oxygen species (ROS) accumulation of P. expansum were analyzed by fluorescence probes. The results showed that the minimum inhibitory concentration (MIC) of the antimicrobial peptide against P. expansum spores was 3.5 AU/mL. The spore germination rate was significantly decreased by 28.30%, 84.57% and 100% by the antimicrobial peptide at concentrations of 0.5 MIC, 1 MIC and 2 MIC compared with the blank control (P < 0.05). After treatment with the antimicrobial peptide, the spores appeared seriously sunken, the intracellular contents were leaked out, and the morphology and structure were changed. The antimicrobial peptide damaged the cell wall of P. expansum, resulting in the leakage of alkaline phosphatase. The antimicrobial peptide depolarized the cell membrane potential in a dose-dependent manner, and increased the cell membrane permeability, leading to K+ leakage. The fluidity of the cell membrane was increased, which in turn resulted in a significant decrease in DPH fluorescence intensity (P < 0.05). The integrity of the cell membrane was damaged by the antimicrobial peptide, so the fluorescence intensity of SYTOX-Green and the contamination rate of PI were increased. Moreover, the antimicrobial peptide at 1 MIC and 2 MIC increased the fluorescence intensity of DCFH-DA significantly (P < 0.05) and resulted in ROS accumulation, which affected the physiology and metabolism of P. expansum spores. This study indicated that the target sites of the antimicrobial peptide against P. expansum spores were mainly the cell membrane and ROS metabolism.

This study investigated the effects of low-pressure cold plasma on the inactivation of Bacillus cereus vegetative cells and spores in an inert matrix (borosilicate glass slide) and in rice grains, using oxygen as ionization gas. Greater reductions in B. cereus counts were observed in vegetative cells rather than spores. The experimental data obtained show that both the power of the plasma treatment and the matrix proved to be determining factors in the inactivation of both the spores and vegetative cells of B. cereus. To characterize the inactivation of B. cereus, experimental data were accurately fitted to the Weibull model. A significant decrease in parameter “a”, representing resistance to treatment, was confirmed with treatment intensification. Furthermore, significant differences in the “a” value were observed between spores in inert and food matrices, suggesting the additional protective role of the food matrix for B. cereus spores. These results demonstrate the importance of considering matrix effects in plasma treatment to ensure the effective inactivation of pathogenic microorganisms, particularly in foods with low water activity, such as rice. This approach contributes to mitigating the impact of foodborne illnesses caused by pathogenic microorganisms.

Rapid Ohia Death (ROD) is caused by two pathogens, Ceratocystis lukuohia and Ceratocystis huliohia. The established species-specific real-time PCR assays targeting the single-copy cerato-platanin gene require DNA from between 2 and 16 spores per reaction for consistent detection, which is suitable for analysis of infected plant tissue but not sensitive enough to consistently detect low spore loads in environmental samples. Here, we present two redesigned qPCR assays targeting the first internal transcribed spacer (ITS) region of the multi-copy ribosomal DNA operon from the respective species, both capable of consistent detection of the pathogen at concentrations as low as 1 fg per reaction, less than the size of the haploid genome. Due to this increased sensitivity, these ITS qPCR assays are superior for analysis of DNA extracted from material collected in airborne particle samplers and from soil. Here, we demonstrate the utility of these qPCR assays for the characterization of windblown and soilborne dispersal of the pathogens, which is critical for the development of management practices that mitigate disease spread. [Figure: see text] The author(s) have dedicated the work to the public domain under the Creative Commons CC0 “No Rights Reserved” license by waiving all of his or her rights to the work worldwide under copyright law, including all related and neighboring rights, to the extent allowed by law, 2023.

ABSTRACT: In the absence of postpasteurization contamination, psychrotolerant, aerobic spore-forming bacteria that survive high-temperature, short-time (HTST) pasteurization, limit the ability to achieve HTST extended shelf-life milk. Therefore, the goal of the current study was to evaluate bacterial outgrowth in milk pasteurized at different temperatures (75, 85, or 90°C, each for 20 s) and subsequently stored at 3, 6.5, or 10°C. An initial ANOVA of bacterial concentrations over 14 d of storage revealed a highly significant effect of storage temperatures, but no significant effect of HTST. At d 14, average bacterial counts for milk stored at 3, 6.5, and 10°C were 1.82, 3.55, and 6.86 log10 cfu/mL, respectively. Time to reach 1,000,000 cfu/mL (a bacterial concentration where consumers begin to notice microbially induced sensory defects in fluid milk) was estimated to be 68, 27, and 10 d for milk stored at 3, 6.5, and 10°C, respectively. Out of 95 isolates characterized with rpoB allelic typing, 6 unique genera, 15 unique species, and 44 unique rpoB allelic types were represented. The most common genera identified were Paenibacillus, Bacillus, and Lysinibacillus. Nonmetric multidimensional scaling identified that Bacillus was significantly associated with 3 and 10°C, whereas Paenibacillus was consistently found across all storage temperatures. Overall, our data show that storage temperature has a substantially larger effect on fluid milk shelf life than HTST and suggests that abuse temperatures (e.g., storage at 10°C) allow for growth of Bacillus species (including Bacillus cereus genomospecies) that do not grow at lower temperatures. This indicates that stringent control of storage and distribution temperatures is critical for producing extended shelf-life HTST milk, particularly concerning new distribution pathways for HTST pasteurized milk (e.g., electronic commerce), and when enhanced control of spores in raw milk is not feasible.

The structures of water cooling systems are prone to microbially-influenced corrosion (MIC) due to the favorable conditions for microbial growth. Biofilm formation accelerates corrosion, leading to reduced system efficiency, structural damage, and significant financial losses. Encapsulating viable bacterial spores and biosurfactant within a silica-based sol-gel coating offers an eco-friendly approach to prevent this type of corrosion. Bacillus clausii, known for its antimicrobial biosurfactant production capability, was utilized in this study to investigate the impact of spores and biosurfactant addition to silica-based sol-gel coatings in inhibiting biofilm formation and preventing corrosion in water cooling systems. Microbiological analysis of the biofilm was conducted using the total plate count method, while the corrosion process was analyzed through electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDS). The viability of B. clausii spores within the sol-gel matrix was determined to be 20.8 %. The presence of bacterial spores and biosurfactant significantly increased the hydrophobicity of the sol-gel coating. Incorporating spores within the sol-gel matrix delayed biofilm formation for up to 12 days, while biosurfactant addition showed the smallest biofilm abundance (2.23×105 CFU/mL) at its maturation phase compare to others. After 180 days of incubation, analysis of Bode and Tafel plots demonstrated that the sol-gel coating containing biosurfactant maintained excellent anti-corrosion performance, exhibiting an impedance of 104 Ω cm2, Ecorr of -0.398 V vs SCE, and icorr of 0.51 µA/cm2. SEM-EDS analysis of the surface sample revealed a comparably smooth and uniform surface with a minimal abundance of exposed Fe atoms at 0.12 %. In conclusion, this study demonstrated the high potency of the sol-gel coating supplemented with biosurfactant in inhibiting biofilm formation and corrosion on metals in water cooling systems.

Abstract Clostridioides difficile spores are considered as the major source responsible for the development of C. difficile infection (CDI), which is associated with an increased risk of death in patients and has become an important issue in infection control of nosocomial infections. Current treatment against CDI still relies on antibiotics, which also damage normal flora and increase the risk of CDI recurrence. Therefore, alternative therapies that are more effective against C. difficile bacteria and spores are urgently needed. Here, we designed an oxidation process using H2O2 containing PBS solution to generate Cl− and peroxide molecules that further process Ag and Au ions to form nanoboxes with Ag–Au peroxide coat covering Au shell and AgCl core (AgAu‐based nanoboxes). The AgAu‐based nanoboxes efficiently disrupted the membrane structure of bacteria/spores of C. difficile after 30–45 min exposure to the highly reactive Ag/Au peroxide surface of the nano structures. The Au‐enclosed AgCl provided sustained suppression of the growth of 2 × 107 pathogenic Escherichia coli for up to 19 days. In a fecal bench ex vivo test and in vivo CDI murine model, biocompatibility and therapeutic efficacy of the AuAg nanoboxes to attenuate CDI was demonstrated by restoring the gut microbiota and colon mucosal structure. The treatment successfully rescued the CDI mice from death and prevented their recurrence mediated by vancomycin treatment. The significant outcomes indicated that the new peroxide‐derived AgAu‐based nanoboxes possess great potential for future translation into clinical application as a new alternative therapeutic strategy against CDI.