Search

Asymmetric seasonal warming trends are evident across terrestrial ecosystems, with winter temperatures rising more than summer ones. Yet, the impact of such asymmetric seasonal warming on soil microbial carbon metabolism and growth remains poorly understood. Using 18O isotope labeling, we examined the effects of a decade-long experimental seasonal warming on microbial carbon use efficiency (CUE) and growth in alpine grassland ecosystems. Moreover, the quantitative stable isotope probing with 18O-H2O was employed to evaluate taxon-specific bacterial growth in these ecosystems. Results show that symmetric year-round warming decreased microbial growth rate by 31% and CUE by 22%. Asymmetric winter warming resulted in a further decrease in microbial growth rate of 27% and microbial CUE of 59% compared to symmetric year-round warming. Long-term warming increased microbial carbon limitations, especially under asymmetric winter warming. Long-term warming suppressed the growth rates of most bacterial genera, with asymmetric winter warming having a stronger inhibition on the growth rates of specific genera (e.g., Gp10, Actinomarinicola, Bosea, Acidibacter, and Gemmata) compared to symmetric year-round warming. Bacterial growth was phylogenetically conserved, but this conservation diminished under warming conditions, primarily due to shifts in bacterial physiological states rather than the number of bacterial species and community composition. Overall, long-term warming escalated microbial carbon limitations, decreased microbial growth and CUE, with asymmetric winter warming having a more pronounced effect. Understanding these impacts is crucial for predicting soil carbon cycling as global warming progresses. [ABSTRACT FROM AUTHOR]

Date syrup is a very rich nutritional and medicinal product. It can be used alone or mixed with other food products. Now, it is widely used as a natural sweetener instead of harmful sugar in several food products. However, date syrup contains higher levels of 5-hydroxyl methyl furfural (5-HMF) (heat-induced toxicant). HMF is normally formed during processing via Maillard reaction as a result of heating. Thus, the present study aims at investigating the effect of gamma irradiation in reducing HMF content and improving the quality properties of date syrup. Date syrup samples (commercial) were irradiated at different doses (15, 20 and 25 kGy). HMF content was determined using the HPLC method. The obtained results showed that γ-irradiation reduced the toxic compound (HMF) in date syrup, where irradiation dose (20 kGy) recorded the lowest HMF level (1956.40 mg/kg) with a reduction percentage of 46.96% compared to the non-irradiated sample. While the non-irradiated sample revealed the highest level of HMF and bacterial growth. Therefore, γ-irradiation is considered an effective treatment that reduces HMF using a particular dose (20 kGy) and prevents microbial growth (20–25 KGy). Furthermore, it may increase the nutritional value by increasing minerals' bioavailability (15 kGy). [ABSTRACT FROM AUTHOR]

Growth rate maximization is an important fitness strategy for microbes. However, the wide distribution of slow-growing oligotrophic microbes in ecosystems suggests that rapid growth is often not favored across ecological environments. In many circumstances, there exist trade-offs between growth and other important traits (e.g., adaptability and survival) due to physiological and proteome constraints. Investments on alternative traits could compromise growth rate and microbes need to adopt bet-hedging strategies to improve fitness in fluctuating environments. Here we review the mechanistic role of trade-offs in controlling bacterial growth and further highlight its ecological implications in driving the emergences of many important ecological phenomena such as co-existence, population heterogeneity and oligotrophic/copiotrophic lifestyles. Trade-offs play a key role in controlling bacterial growth and shaping microbial phenotypes, which further drives the emergence of ecologically relevant phenomena including co-existence, population heterogeneity and oligotrophic/copiotrophic lifestyles. [ABSTRACT FROM AUTHOR]

This study aimed to investigate the biocompatibility, osteogenic and antibacterial activity of biomedical devices based on Magnesium (Mg) Alloys manufactured by Superplastic Forming process (SPF) and subjected to Hydrothermal (HT) and Sol-Gel Treatment (Sol-Gel). Mg-SPF devices subjected to Hydrothermal (Mg-SPF+HT) and Sol-Gel Treatment (Mg-SPF+Sol-Gel) were investigated. The biocompatibility of Mg-SPF+Sol-Gel and Mg-SPF+HT devices was observed by indirect and direct cytotoxicity assays, whereas the colonization of sample surfaces was assessed by confocal microscopy. qRT-PCR analysis and microbial growth curve analyses were employed to evaluate the osteogenic and antibacterial activity of both SPF-Mg treated devices, respectively. Mg-SPF+HT and Mg-SPF+Sol-Gel showed a high degree of biocompatibility. Analysis of mRNA expression of osteogenic genes in cells cultured on Mg-treated devices revealed a significant upregulation of the expression levels of BMP2 and Runx-2. Furthermore, the bacterial growth in strains developed in contact with both the Mg-SPF+HT and Mg-SPF+Sol-Gel devices was lower than that observed in the control. Hydrothermal and Sol-Gel Treatments of Mg alloys obtained through the SPF process demonstrated bioactive, osteogenic and antibacterial activity, offering a promising alternative to conventional Mg-based devices. The obtained Mg-based materials may have the potential to enhance the tunability of temporary devices in maxillary reconstruction, eliminating the need for second surgeries, and ensuring a good bone reconstruction and a reduced implant failure rate due to bacterial infections. ● Surface-functionalized Mg-based materials may promote osteogenesis. ● HT and Sol-Gel treatment both improved osteogenic/osteoinductive properties. ● Mg-based devices exhibited antibacterial properties. ● Mg-based materials seemed to be promising in treating refractory bone diseases. [ABSTRACT FROM AUTHOR]

We studied the efficacy of different formulations of polyphenol extracts (mainly containing hydroxytyrosol and tyrosol) from olive mill vegetation water on the microflora on the surfaces of game meat cuts with high or low initial bacterial loads. Meat with a high microbial load (>5 Log cfu/g; mean value = 6.83 ± 0.45 standard deviation) was immersed for 10 or 60 sec into 25% and 10% solutions of microencapsulated freeze-dried and non-encapsulated polyphenolic extracts. Aerobic colony, Enterobacteriaceae, Pseudomonas spp., and lactic acid bacteria counts were determined on treated samples compared to controls after 7 days of storage (in vacuum-packed conditions at +3 °C). Significant differences were registered only for aerobic colony count for a 10% liquid extract treatment (0.64 log reduction). In contrast, the dipping or immersion of game meat with low initial microbial loads (<5 Log cfu/g; mean value = 3.58 ± 0.72 standard deviation) in 10% solutions of the polyphenol extracts effectuated significant reductions in all bacteria counts (p < 0.002) at 7 and 14 days of storage for different extracts, independently from the application methods. The use of the extracts to inhibit bacterial growth in game meat should only be considered if a good hygienic baseline is guaranteed. [ABSTRACT FROM AUTHOR]

The duration of lag phase can be used as an organismal fitness marker; however, it is often underreported as its estimation may be challenging and method and parameters dependent. Moreover, there are no publicly available tools to calculate lag duration by different methods.We developed a shiny‐based web application (https://microbialgrowth.shinyapps.io/lag%5fcalulator/) where the lag duration can be calculated based on the user‐specified growth curve data, and for various explicitly specified methods, parameters and data preprocessing techniques. Additionally, we release an R package 'miLAG' that can be further customised and developed.We also describe in short the assumptions, advantages and disadvantages of the most popular lag calculation methods and propose a decision tree to choose a method most suited to one's data.Finally, we show some working examples of how to calculate lag duration using our shiny server. [ABSTRACT FROM AUTHOR]

Post-harvest changes in the quality of cut and whole S. latissima upon 23 days storage with or without acidification at different temperatures were studied by bacterial counts, amino acids composition, and 1H-NMR profiling of extracted metabolites. Lowering the temperature inhibited bacterial growth, and seaweed stored 10 days at 4°C had the same bacterial counts as seaweed stored 2 days at room temperature. Cutting reduced the bacterial degradation of mannitol, free amino acids, and other low molecular components but made proteins and carbohydrates more available for enzymatic hydrolysis. Acidification hindered microbial growth and reduced degradation of amino acids and other components. [ABSTRACT FROM AUTHOR]

DaxibotulinumtoxinA-lanm for injection (DAXI) is a unique US Food and Drug Administration-approved product comprising daxibotulinumtoxinA and a stabilizing excipient peptide (RTP004). DAXI has a longer-labeled shelf life (72 h) following reconstitution than other botulinum toxin type A products. Here, we report the stability and microbial control of reconstituted DAXI when stored at 2 °C–8 °C over a period of 36 days (Study 1) and 7 days (Study 2) following reconstitution with unpreserved or preserved saline. The pH and biological activity of reconstituted DAXI in the 50 U/vial and 100 U/vial formats remained stable at the final assessed time point in both preserved and unpreserved saline when refrigerated (2 °C–8 °C). No changes in recoverable 150 kDa neurotoxin (measured by enzyme-linked immunosorbent assay) were observed over 6 days of refrigeration. Bacterial growth or pathogen proliferation was not observed in DAXI reconstituted in preserved or unpreserved saline in both studies. [ABSTRACT FROM AUTHOR]

Background: Identification of the causative agent is an essential requirement for better treatment of bloodstream infection. The BacT/Alert 3D (BioMérieux, Marcy l'Étoile, France), is a blood culture system equipped with CO2 sensors to monitor the growth of microorganisms in blood culture bottles designed to optimize bacterial growth. The aim of this study was to determine the performance of this equipment in detecting bacterial pathogens from patients with bloodstream infection in the context of low-and-middle-income countries (LMICs), with Bobo-Dioulasso Teaching Hospital as a case study. Methodology: A cross-sectional study was conducted over a period of 5 months at the Sourô Sanou University Hospital, Bobo-Dioulasso, Burkina Faso, a low-income country. Blood samples from a total of 231 patients with clinical suspicion of bloodstream infections were collected and processed according to the manufacturer's instructions. Results: Sixty-nine of the 231 blood culture samples of patients were positive, giving a bacteriological yield of 29.9%. Escherichia coli, Salmonella spp, and Staphylococcus aureus were the top three bacterial species isolated. Conclusion: The implementation of the BacT/Alert 3D system has significantly enhanced the diagnosis of bacteraemia in the Bobo-Dioulasso Teaching Hospital. This enhancement is marked by time savings in patient care, reduced staff workload, and an increased bacteriological yield over time. [ABSTRACT FROM AUTHOR]

Antibiotic-resistant bacteria are one of the main global health problems that can affect humans, animals and environment. In this work, out of 525 isolates, 39 Bacillus strains, which represented six species as B. atrophaeus, B. subtilis, Paenibacillus polymyxa, B. amyloliquefaciens and B. tequilensis were in-vitro tested for ampicillin resistance on NA media, and profound inhibition of bacteria growth was observed 24 hours post incubation. The data indicated that resistance to ampicillin was species-related as B. subtilis, (N = 20; % 50), B. amyloliquefaciens, (N = 10; % 60), and B. atrophaeus (N = 3; % 33.3), B. poenibacillus (N = 2; % 0) and for B. tequilensis (N = 4; % 75). The percentage of zone inhibition of the Bacillus colonies ranged from 0 to 75 %, compared to the untreated control. However, 51% of tested Bacillus strains were not sensitive to ampicillin, suggesting the existence of potential risk for Bacillus spp. infections. The results of this study suggest that the Syrian Bacillus strains are variable in their susceptibility towards ampicilin, and the presence of resistant strains is of concern about how this resistance could spread to other bacteria, and then to humans. [ABSTRACT FROM AUTHOR]

Environmental concerns, among other causes, are leading to meat replacement in the diet by healthy, nutritious, and tasty foods. Alternative protein sources of plant origin can be an alternative to meat but their low biological value proteins can be a problem. Novel foods, such as insect meals, can meet current consumer's demands. Therefore, this research has developed innovative prototypes of analog burgers with insect and vegetable proteins. Concerned about health and allergies, a prototype incorporating soya to satisfy coeliacs was developed. An iterative and heuristic process was carried out to test the product development feasibility. The main raw materials used were insect flour (Tenebrio molitor), seitan, and soya. In addition, oat and sodium alginate were used as binders. The shelf-life of the new product was evaluated by physicochemical (pH, aw, moisture, color, acidity, and peroxide index) and sensory analysis (quantitative analysis QDA). The production of the burger analogs was feasible. Product characterization showed significant differences (p < 0.05) among samples for organoleptic properties, highlighting texture changes. Using a multivariate model, it was established that the "best before date" occurs at seven days for all developed prototypes, conditioned by microbial growth. Finally, the spoilage model indicated an important contribution to bacterial growth with a notable modification to the pastiness and hardness of the burger analogs developed. [ABSTRACT FROM AUTHOR]

In predictive microbiology, primary and secondary models can be used to predict microbial growth, usually in a two-step modelling approach. The inverse dynamic modelling approach is an alternative method to direct modelling methods, in which the primary and secondary models are fitted simultaneously from non-isothermal data, minimising experimental effort and costs. Thus, the main aim of the present study was to compare the prediction capabilities of the mathematical modelling approaches used for calculating growth kinetics of microorganisms in predictive food microbiology field. For this purpose, the bacterial growth data of Pseudomonas spp. in oyster mushroom (Pleurotus ostreatus) subjected to isothermal and non-isothermal storage temperatures were collected from previously published growth curves. Temperature-dependent kinetic growth parameters (maximum specific growth rate 'µ max ' and lag phase duration ' λ ') were described as a function of storage temperature using the direct two-step, direct one-step and inverse dynamic modelling approach based on Baranyi and Huang models. The fitting capability of the modelling approaches was separately compared, and the one-step modelling approach for the direct methods provided better goodness of fit results regardless of used primary models, which leads the Huang model with being RMSE = 0.226 and R2adj = 0.949 became best for direct methods. Like seen in direct methods, the Huang model gave better goodness of fit results than Baranyi model for inverse method. Results revealed there was no significant difference (p > 0.05) between the growth kinetic parameters obtained from direct one-step modelling approach and inverse modelling approaches based on the Huang model. Satisfactorily statistical indexes show that the inverse dynamic modelling approach can be reliably used as an alternative way of describing the growth behaviour of Pseudomonas spp. in oyster mushroom in a fast and minimum labour effort. [ABSTRACT FROM AUTHOR]

Purpose: This study investigated whether selected natural products could specifically target the growth of a caries-associated bacterial species (Streptococcus mutans) without affecting the viability of a health-associated oral commensal bacterial species (Streptococcus sanguinis).Materials and Methods: Agar diffusion assays were used to screen the natural products for bacterial-growth inhibitory effects and the diameters of the inhibitory zones for the two bacterial species compared. The minimum inhibitory concentrations (MIC) of the natural products that showed growth inhibitory effects were determined using the broth microdilution method.Results: Except for the berry extracts (cranberry, wild blueberry, and strawberry), all the other selected natural products (peppermint, ginger, cinnamon, rosemary, liquorice, xanthorrrhizol, tt-farnesol, guaijaverin, and macelignan) exhibited varying degrees of bacterial growth inhibition. The MIC values ranged from as low as 4 µg/ml for xanthorrrhizol to 1000 µg/ml for guaijaverin. All the growth inhibitory natural agents tested showed similar inhibition for both S. mutans and S. sanguinis.Conclusions: Although several natural products exerted significant antibacterial effects, none had selective inhibitory action on the growth of S. mutans. [ABSTRACT FROM AUTHOR]

Acetate, a major by‐product of glycolytic metabolism in Escherichia coli and many other microorganisms, has long been considered a toxic waste compound that inhibits microbial growth. This counterproductive auto‐inhibition represents a major problem in biotechnology and has puzzled the scientific community for decades. Recent studies have however revealed that acetate is also a co‐substrate of glycolytic nutrients and a global regulator of E. coli metabolism and physiology. Here, we used a systems biology strategy to investigate the mutual regulation of glycolytic and acetate metabolism in E. coli. Computational and experimental analyses demonstrate that decreasing the glycolytic flux enhances co‐utilization of acetate with glucose. Acetate metabolism thus compensates for the reduction in glycolytic flux and eventually buffers carbon uptake so that acetate, rather than being toxic, actually enhances E. coli growth under these conditions. We validated this mechanism using three orthogonal strategies: chemical inhibition of glucose uptake, glycolytic mutant strains, and alternative substrates with a natively low glycolytic flux. In summary, acetate makes E. coli more robust to glycolytic perturbations and is a valuable nutrient, with a beneficial effect on microbial growth. Synopsis: Acetate is traditionally viewed as a toxic by‐product of glycolytic metabolism that inhibits microbial growth. This study demonstrates that acetate can act as a co‐substrate of glycolytic nutrients and promotes Escherichia coli growth when the glycolytic flux is low.Glycolytic flux determines the role of acetate as a by‐product or co‐substrate of glycolytic nutrients.Acetate utilization by the Pta‐AckA pathway is enhanced at reduced glycolytic flux.Acetate promotes bacterial growth at low glycolytic flux.Acetate increases the robustness of E. coli responses to glycolytic perturbations by buffering carbon uptake. [ABSTRACT FROM AUTHOR]

Copyright of @limentech: Ciencia y Tecnología Alimentaria is the property of Journal @limentech, University of Pamplona 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.)

Seabird guano enters coastal waters providing bioavailable substrates for microbial plankton, but their role in marine ecosystem functioning remains poorly understood. Two concentrations of the water soluble fraction (WSF) of gull guano were added to different natural microbial communities collected in surface waters from the Ría de Vigo (NW Spain) in spring, summer, and winter. Samples were incubated with or without antibiotics (to block bacterial activity) to test whether gull guano stimulated phytoplankton and bacterial growth, caused changes in taxonomic composition, and altered phytoplankton–bacteria interactions. Alteromonadales, Sphingobacteriales, Verrucomicrobia and diatoms were generally stimulated by guano. Chlorophyll a (Chl a) concentration and bacterial abundance significantly increased after additions independently of the initial ambient nutrient concentrations. Our study demonstrates, for the first time, that the addition of guano altered the phytoplankton–bacteria interaction index from neutral (i.e. phytoplankton growth was not affected by bacterial activity) to positive (i.e. phytoplankton growth was stimulated by bacterial activity) in the low‐nutrient environment occurring in spring. In contrast, when environmental nutrient concentrations were high, the interaction index changed from positive to neutral after guano additions, suggesting the presence of some secondary metabolite in the guano that is needed for phytoplankton growth, which would otherwise be supplied by bacteria. [ABSTRACT FROM AUTHOR]

Floral nectar is frequently colonised by microbes. However, nectar microbial communities are typically species‐poor and dominated by few cosmopolitan genera. One hypothesis is that nectar constituents may act as environmental filters. We tested how five non‐sugar nectar compounds as well as elevated sugar impacted the growth of 12 fungal and bacterial species isolated from nectar, pollinators, and the environment. We hypothesised that nectar isolated microbes would have the least growth suppression. Additionally, to test if nectar compounds could affect the outcome of competition between microbes, we grew a subset of microbes in co‐culture across a subset of treatments. We found that some compounds such as H2O2 suppressed microbial growth across many but not all microbes tested. Other compounds were more specialised in the microbes they impacted. As hypothesised, the nectar specialist yeast Metschnikowia reukaufii was unaffected by most nectar compounds assayed. However, many non‐nectar specialist microbes remained unaffected by nectar compounds thought to reduce microbial growth. Our results show that nectar chemistry can influence microbial communities but that microbe‐specific responses to nectar compounds are common. Nectar chemistry also affected the outcome of species interactions among microbial taxa, suggesting that non‐sugar compounds can affect microbial community assembly in flowers. [ABSTRACT FROM AUTHOR]

Although wooden cutting boards have been used for centuries, debate remains on how best to coat/seal the boards for microbial protection. A growing body of the literature points to the hygroscopicity of wood—its ability to draw water and bacteria from its surface, deep into the wood, where the bacteria are trapped and die—as the wood attempts to even out its moisture content. There is little research as to how coatings affect this mechanism. In this study, four wood species were coated with either a hardening or nonhardening oil and then, were inoculated with either Listeria or Salmonella, then 'stamped' onto sterile agar plates at given time intervals to check microbial growth. The coated woods had significantly more recoverable bacteria on their surface than did the uncoated samples. There was no significant difference in performance between the oils. Remaining bacterial loads did vary significantly by wood species, with European beech having significantly less surface bacteria when inoculated with Salmonella, and the oak species having significantly less surface bacteria with Listeria. Multiple factors appeared to affect the ability of wood to move bacteria from its surface, including porosity of the wood, type of bacteria applied, and time. These results run counter to popular understanding of wood cutting board maintenance and will hopefully impact the way households and professional kitchens use and care for their food-contact wood in the future. [ABSTRACT FROM AUTHOR]

The bioconversion of red tilapia by-products in protein hydrolysates using neutrase and papain demonstrated a high degree of hydrolysis and yield. Tilapia protein hydrolysates (TPH) contained high content in minerals, essential amino acids, and low-molecular-weight peptides. TPH showed water solubility and emulsifying capacity at neutral and alkaline conditions but low foam stability. TPH are also able to scavenge DPPH and ABTS free radicals and high efficiency for bacterial growth. Therefore, TPH represent an interesting source of functional and bioactive products to be added in food formulations, a high-performance bacterial culture media, and a sustainable way to reduce tilapia-processing wastes. [ABSTRACT FROM AUTHOR]

Prediction of microbial growth is the main topic within the area of predictive microbiology. A commonly used framework is the so-called gamma concept which is to view the bacterial growth rate as a product of a bacteria- and medium specific maximum instantaneous factor, and several environmental factors. Traditionally environmental factors are assumed to be constant, leading to exponential growth. In the current study, we expand the gamma concept to include changing dynamic environmental factors, exemplified by pH, and show how this might affect estimates for Listeria monocytogenes growth rates and thereby predicted shelf-life. The study shows how substantial environmental changes might lead to large biases for the estimated growth and shelf-life, if not accounted for in the model. Finally, the study shed some light on how accuracy for the growth rate estimates might be improved by allocating more weight to observations prone to favorable than unfavorable environmental conditions. • Changing environment during storage leads to biased estimates for bac-terial growth. • In the study the gamma principle is extended to include changing environment. • The study exemplifies the theory with a model for pH evolution. • Shelf life is overestimated with decreasing growth conditions if unaccounted for. • Observations should be allocated weight in line with their environ-mental conditions. [ABSTRACT FROM AUTHOR]

In this study, Alyssum homolocarpum (AH) and Lepidium sativum seed gum (LS) at different ratios 1:0, 1:1, and 0:1 utilized to encapsulate red onion extract (ROE) for beef coating through immersion. Different concentrations of ROE (400, 800, 1200 and 1600 ppm) showed high antioxidant activity due to phenolic and flavonoid compounds. In terms of mean size, the lowest particle size was observed in ROE encapsulated in Alyssum homolocarpum gum (7.4 3 89.3 nm). And nanoemulsions prepared in Lepidium sativum seed gum had higher particle size (145.7 3 2.3 nm). Negative -zeta potential was observed in all nanoemulsions. Meat samples were kept at 4 ° C for 20 days and the values of thiobarbituric acid, color indices L *, a *, b *, total bacterial count were examined at 4 - day intervals. The results showed that ROE encapsulated in LS and AH was more effective in delaying the microbial and chemical reactions of coated meat fillets. Due to reduced bacterial growth, decreased thiobarbituric number and microbial growth, shelf life increased from 4 days to 16 days. This study confirmed that ROE encapsulated in the combined coating of AH and LS is a potential coating to improve the quality and shelf life of beef fillets. [ABSTRACT FROM AUTHOR]

Microorganisms growing in their habitat constitute a complex system. How the individual constituents of the environment contribute to microbial growth remains largely unknown. The present study focused on the contribution of environmental constituents to population dynamics via a high-throughput assay and data-driven analysis of a wild-type Escherichia coli strain. A large dataset constituting a total of 12,828 bacterial growth curves with 966 medium combinations, which were composed of 44 pure chemical compounds, was acquired. Machine learning analysis of the big data relating the growth parameters to the medium combinations revealed that the decision-making components for bacterial growth were distinct among various growth phases, e.g., glucose, sulfate, and serine for maximum growth, growth rate, and growth delay, respectively. Further analyses and simulations indicated that branched-chain amino acids functioned as global coordinators for population dynamics, as well as a survival strategy of risk diversification to prevent the bacterial population from undergoing extinction. [ABSTRACT FROM AUTHOR]

The higher moisture level (70–80%) in wet brewer's grain (WBG) poses two major difficulties when using it as a feed for different classes of animals. Firstly, transport of WBG is costly. Secondly, the rich polysaccharide and protein content and the high moisture content of WBG make it susceptible to microbial growth and spoilage. Therefore this study was planned to examine the effect of soaking, sun drying and ensiling on nutritional and fungal load dynamics of wet brewers' grain. Wet brewers' grain was collected from Meta Abo, Habesha, Dashen and Bedele breweries, Ethiopia. The sample was labeled and kept in a separate sterile bag and stored under − 20 °C. For soaking, 2 kg sample was uniformly treated with salt (3% on dry matter basis), placed in plastic container and covered with a lead for partial aerobic condition. Wet brewers' grain (2 kg) was exposed to sun drying for the consecutive three days, eight hours per day. The sample (2 kg) with molasses (3% on dry matter basis) was ensiled in a plastic bottle. All samples except sun dried, were subjected to oven drying at 55 °C for 72 h. To evaluate insacco degradability, samples were incubated for 6, 12, 24, 48, 72 and 96 h in nylon bags (6.5 × 14 cm, 50 μm pore size) placed in ventral sac of three cannulated Boran-Friesian steers (550 ± 15 kg live weight). The samples (25 g) were dissolved in 225 ml of peptone water. Potato Dextrose agar medium was injected with 1 ppm per each 100 ml of agar with chloramphenicol and streptomycin to restrict bacterial growth. Plates were incubated aerobically at 28 ± 1 °C for 3 day and growing molds and yeast colonies were directly counted. The sample received from Meta Abo brewery factory had the higher (p < 0.05) acid detergent fiber, lignin and digestible organic matter but comparable dry matter (DM), ash, crude protein (CP) and neutral detergent fiber with other breweries. The minimal loss on DM and other nutrients, lower fungal, yeast and mold colony counts and the higher CP digestion kinetics was observed in ensiling techniques. If supply is not a constraint under local conditions, ensiling can be recommended as the best conservation practice. [ABSTRACT FROM AUTHOR]

Cracks on the surface of cementitious composites represent an entrance gate for harmful substances—particularly water—to devastate the bulk of material, which results in lower durability. Autogenous crack-sealing is a significantly limited mechanism due to a combination of the hydration process and calcite nucleation, and self-healing cementitious composites are a research area that require a great deal of scientific effort. In contrast to time-consuming experiments (e.g., only the preparation of an applicable bare concrete sample itself requires more than 28 days), appropriately selected mathematical models may assist in the deeper understanding of self-healing processes via bacteria. This paper presents theoretically oriented research dealing with the application of specific bacteria (B. pseudofirmus) capable of transforming available nutrients into calcite, allowing for the cracks on the surfaces of cementitious materials to be repaired. One of the principal objectives of this study is to analyze the sensitivity of the bacterial growth curves to the system parameters within the context of the logistic model in the Monod approach. Analytically calculated growth curves for various parameters (initial inoculation concentration, initial nutrition content, and metabolic activity of bacteria) are compared with experimental data. The proposed methodology may also be applied to analyze the growth of microorganisms of nonbacterial origin (e.g., molds, yeasts). [ABSTRACT FROM AUTHOR]

This paper focuses on the comparison of microbial biomass increase (cell culture growth) using field-relevant testing methods and moving away from colony counts. Challenges exist in exploring the antimicrobial growth of fastidious strains, poorly culturable bacteria and bacterial communities of environmental interest. Thus, various approaches have been explored to follow bacterial growth that can be efficient surrogates for classical optical density or colony-forming unit measurements. Here, six species grown in pure culture were monitored using optical density, ATP assays, DNA concentrations and 16S rRNA qPCR. Each of these methods have different advantages and disadvantages concerning the measurement of growth and activity in complex field samples. The species used as model systems for monitoring were: Acetobacterium woodii, Bacillus subtilis, Desulfovibrio vulgaris, Geoalkalibacter subterraneus, Pseudomonas putida and Thauera aromatica. All four techniques were found to successfully measure and detect cell biomass/activity differences, though the shape and accuracy of each technique varied between species. DNA concentrations were found to correlate the best with the other three assays (ATP, DNA concentrations and 16S rRNA-targeted qPCR) and provide the advantages of rapid extraction, consistency between replicates and the potential for downstream analysis. DNA concentrations were determined to be the best universal monitoring method for complex environmental samples. [ABSTRACT FROM AUTHOR]

Extracorporeal Membrane Oxygenation (ECMO) is a life support device for patients with severe heart and/or lung failure. Emergency situations require immediate ECMO response. Primed circuits have become a routine practice, as it may take 30-60 min to assemble and prime. There remains a lack of data to support the sterility of primed and stored ECMO circuits. This bench study assessed the impact of storage environment and priming solution on specific microbial growth of primed ECMO circuits.Twelve adult ECMO circuits were tested for sterility for 56 days between September-December 2020. Circuits were assembled and primed in a perfusion lab in Chicago, IL. Six were stored in a sterile environment and six in a non-sterile environment, with three circuits primed using normal saline (NaCl) and three with Plasmalyte-A for each environment. Samples were collected on days 0, 3, 7, 14, 28, 42, and 56 in anaerobic bottle cultures testing for potential pathogen growth, such as Staphylococcus aureus, Pseudomonas aeruginosa, and Escherichia coli.Samples obtained from the 12 primed ECMO circuits demonstrated no microbial growth of S. aureus, P. aeruginosa, and E. coli in the bottle cultures. Similarly, there was no difference in the circuit sterility based on the storage environment (sterile vs nonsterile) or priming solution (NaCl vs Plasmalyte-A).Our findings showed that ECMO circuits can be primed for 56 days without evidence of the specified bacterial growth. Furthermore, the storage conditions and the prime utilized did not affect the sterility of the primed ECMO circuits. [ABSTRACT FROM AUTHOR]

A mathematical model of the fed-batch bioconversion of 1,3-propanediol into 3-hydroxypropionic acid using acetic acid bacteria is proposed. The model includes the microbial growth, the oxidation of 1,3-propanediol to 3-hydroxypropionaldehyde followed by a second oxidation reaction to 3-hydroxypropionic acid. The inhibitory effect of the total acid concentration upon the biological reactions was considered as well as the effect of pH on bacterial growth. A special attention was paid to make accurate pH predictions as pH is a key parameter that influences the microbial growth and bioconversion and also defines the strategy of downstream processing for acid recovery. The buffering capacity of the complex biological medium was found to change throughout the bioconversion. In addition to describing satisfactorily a set of experiments reported in the literature, the model was successfully used to predict metabolite concentrations and the resulting pH in new operating conditions with free pH dynamics. A sensitivity analysis was performed to identify the most influential parameters of the model. The proposed model represents a valuable tool for bioprocess design as it describes the detailed kinetics of 1,3-propanediol oxidation to 3-hydroxypropionic acid by acetic acid bacteria in bioreactor. Additionally, the pH prediction is a major feature of this model, which could guide the identification of optimal operating conditions for microbial activity with a simultaneous in-situ recovery process. • 3-hydroxypropionic acid was produced at low pH using acetic acid bacteria. • Model parameters were estimated through global and local approaches. • Modeling the buffering capacity of the medium enabled accurate pH predictions. • The model was validated using independent experiments performed at uncontrolled pH. • Sensitivity analysis was performed to identify the most influential parameters. [ABSTRACT FROM AUTHOR]

Purpose: Although 5% povidone-iodine (PVP-I) is frequently used as an ocular antiseptic agent, there is a lack of consensus regarding the effects of PVP-I concentration, storage after opening, and compounded preparation on PVP-I antisepsis. We performed a series of in-vitro experiments to determine the impact of these factors on PVP-I’s inhibition of common causes of post-procedural eye infection.Inhibition of microorganism growth was measured in-vitro as a function of active PVP-I exposure time. In control experiments, PVP-I was inactivated before microorganism exposure. Tested PVP-I solutions varied in concentration (0.6%, 5%, or 10%), length of storage after opening (0, 7, or 30 days), and preparation (commercial vs.compounded from stock PI solution). Tested pathogens included S. epidermidis, S. viridans, P. aeruginosa, methicillin-resistant S. aureus, methicillin-sensitive S. aureus, and C. albicans.PVP-I solutions inhibited all bacterial growth by 3 min and fungal growth by 15 s. Compared to 5% PVP-I, the 0.6% PVP-I was less effective in inhibiting S. viridans growth (200 ± 0 colonies vs. 7 ± 8 at 30 s, P = 0.0004; 183 ± 21 vs. 0 ± 0 at 1 min, P = 0.018), but more effective in inhibiting P. aeruginosa (30 ± 20 vs. 200 ± 0 at 15 s, P = 0.019). Compared to commercial and newly-opened PVP-I solutions, compounded preparations and solutions stored for 7 or 30 days after bottle opening either preserved or improved antiseptic efficacy against tested microorganisms.Concentration of PVP-I solution affects antiseptic efficacy within 1 min of exposure, but all solutions performed equivalently at 3 min. In contrast to results of prior studies investigating dilute PVP-I, the 0.6% PVP-I did not demonstrate a uniformly equivalent or superior anti-septic effect. Compounded preparation and storage length after bottle opening did not decrease PVP-I antiseptic activity.Methods: Although 5% povidone-iodine (PVP-I) is frequently used as an ocular antiseptic agent, there is a lack of consensus regarding the effects of PVP-I concentration, storage after opening, and compounded preparation on PVP-I antisepsis. We performed a series of in-vitro experiments to determine the impact of these factors on PVP-I’s inhibition of common causes of post-procedural eye infection.Inhibition of microorganism growth was measured in-vitro as a function of active PVP-I exposure time. In control experiments, PVP-I was inactivated before microorganism exposure. Tested PVP-I solutions varied in concentration (0.6%, 5%, or 10%), length of storage after opening (0, 7, or 30 days), and preparation (commercial vs.compounded from stock PI solution). Tested pathogens included S. epidermidis, S. viridans, P. aeruginosa, methicillin-resistant S. aureus, methicillin-sensitive S. aureus, and C. albicans.PVP-I solutions inhibited all bacterial growth by 3 min and fungal growth by 15 s. Compared to 5% PVP-I, the 0.6% PVP-I was less effective in inhibiting S. viridans growth (200 ± 0 colonies vs. 7 ± 8 at 30 s, P = 0.0004; 183 ± 21 vs. 0 ± 0 at 1 min, P = 0.018), but more effective in inhibiting P. aeruginosa (30 ± 20 vs. 200 ± 0 at 15 s, P = 0.019). Compared to commercial and newly-opened PVP-I solutions, compounded preparations and solutions stored for 7 or 30 days after bottle opening either preserved or improved antiseptic efficacy against tested microorganisms.Concentration of PVP-I solution affects antiseptic efficacy within 1 min of exposure, but all solutions performed equivalently at 3 min. In contrast to results of prior studies investigating dilute PVP-I, the 0.6% PVP-I did not demonstrate a uniformly equivalent or superior anti-septic effect. Compounded preparation and storage length after bottle opening did not decrease PVP-I antiseptic activity.Results: Although 5% povidone-iodine (PVP-I) is frequently used as an ocular antiseptic agent, there is a lack of consensus regarding the effects of PVP-I concentration, storage after opening, and compounded preparation on PVP-I antisepsis. We performed a series of in-vitro experiments to determine the impact of these factors on PVP-I’s inhibition of common causes of post-procedural eye infection.Inhibition of microorganism growth was measured in-vitro as a function of active PVP-I exposure time. In control experiments, PVP-I was inactivated before microorganism exposure. Tested PVP-I solutions varied in concentration (0.6%, 5%, or 10%), length of storage after opening (0, 7, or 30 days), and preparation (commercial vs.compounded from stock PI solution). Tested pathogens included S. epidermidis, S. viridans, P. aeruginosa, methicillin-resistant S. aureus, methicillin-sensitive S. aureus, and C. albicans.PVP-I solutions inhibited all bacterial growth by 3 min and fungal growth by 15 s. Compared to 5% PVP-I, the 0.6% PVP-I was less effective in inhibiting S. viridans growth (200 ± 0 colonies vs. 7 ± 8 at 30 s, P = 0.0004; 183 ± 21 vs. 0 ± 0 at 1 min, P = 0.018), but more effective in inhibiting P. aeruginosa (30 ± 20 vs. 200 ± 0 at 15 s, P = 0.019). Compared to commercial and newly-opened PVP-I solutions, compounded preparations and solutions stored for 7 or 30 days after bottle opening either preserved or improved antiseptic efficacy against tested microorganisms.Concentration of PVP-I solution affects antiseptic efficacy within 1 min of exposure, but all solutions performed equivalently at 3 min. In contrast to results of prior studies investigating dilute PVP-I, the 0.6% PVP-I did not demonstrate a uniformly equivalent or superior anti-septic effect. Compounded preparation and storage length after bottle opening did not decrease PVP-I antiseptic activity.Conclusions: Although 5% povidone-iodine (PVP-I) is frequently used as an ocular antiseptic agent, there is a lack of consensus regarding the effects of PVP-I concentration, storage after opening, and compounded preparation on PVP-I antisepsis. We performed a series of in-vitro experiments to determine the impact of these factors on PVP-I’s inhibition of common causes of post-procedural eye infection.Inhibition of microorganism growth was measured in-vitro as a function of active PVP-I exposure time. In control experiments, PVP-I was inactivated before microorganism exposure. Tested PVP-I solutions varied in concentration (0.6%, 5%, or 10%), length of storage after opening (0, 7, or 30 days), and preparation (commercial vs.compounded from stock PI solution). Tested pathogens included S. epidermidis, S. viridans, P. aeruginosa, methicillin-resistant S. aureus, methicillin-sensitive S. aureus, and C. albicans.PVP-I solutions inhibited all bacterial growth by 3 min and fungal growth by 15 s. Compared to 5% PVP-I, the 0.6% PVP-I was less effective in inhibiting S. viridans growth (200 ± 0 colonies vs. 7 ± 8 at 30 s, P = 0.0004; 183 ± 21 vs. 0 ± 0 at 1 min, P = 0.018), but more effective in inhibiting P. aeruginosa (30 ± 20 vs. 200 ± 0 at 15 s, P = 0.019). Compared to commercial and newly-opened PVP-I solutions, compounded preparations and solutions stored for 7 or 30 days after bottle opening either preserved or improved antiseptic efficacy against tested microorganisms.Concentration of PVP-I solution affects antiseptic efficacy within 1 min of exposure, but all solutions performed equivalently at 3 min. In contrast to results of prior studies investigating dilute PVP-I, the 0.6% PVP-I did not demonstrate a uniformly equivalent or superior anti-septic effect. Compounded preparation and storage length after bottle opening did not decrease PVP-I antiseptic activity. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Chinese Institute of Food Science & Technology is the property of Journal of Chinese Institute of Food Science & Technology Periodical Office 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.)

Bio-plastics are eco-friendly biopolymer finding tremendous application in food and pharmaceutical industries. Bio-plastics have suitable physicochemical, mechanical properties, and does not cause any type of hazardous pollution upon disposal but have high production cost. This can be minimized by screening potential bio-polymers producing strains, selecting inexpensive raw material, simulation and optimization of cultivation condition. In this study, simulation of bacterial production of poly-β-hydroxybutyrate from methane in vertical loop fermentor was carried out by Comsol 5.2 software in 3-dimensional mode. Mass transfer in the process of bacterial growth was investigated via the feed of methane substrate. The graphs of cell density and growth confirmed the results of the simulation according to time. Meshing and independence analysis of the mesh carried out. The initial concentration of microorganism was 0.001 g/L than in the optimal condition and different duration of time was reached 50% of methane and 50% of gas in the reactor that was the highest value of growth microorganism. The results of the simulation were confirmed to experimental results with less than 5% error. [ABSTRACT FROM AUTHOR]

Antimicrobial peptides (AMPs) are versatile molecules with broad antimicrobial activity produced by representatives of the three domains of life. Also, there are derivatives of AMPs and artificial short peptides that can inhibit microbial growth. Beyond killing microbes, AMPs at grow sub-inhibitory concentrations also exhibit antivirulence activity against critical pathogenic bacteria, including ESKAPE pathogens. Anti-virulence therapies are an alternative to antibiotics since they do not directly affect viability and growth, and they are considered less likely to generate resistance. Bacterial biofilms significantly increase antibiotic resistance and are linked to establishing chronic infections. Various AMPs can kill biofilm cells and eradicate infections in animal models. However, some can inhibit biofilm formation and promote dispersal at subgrowth inhibitory concentrations. These examples are discussed here, along with those of peptides that inhibit the expression of traits controlled by quorum sensing, such as the production of exoproteases, phenazines, surfactants, toxins, among others. In addition, specific targets that are determinants of virulence include secretion systems (type II, III, and VI) responsible for releasing effector proteins toxic to eukaryotic cells. This review summarizes the current knowledge on the anti-virulence properties of AMPs and the future directions of their research. [ABSTRACT FROM AUTHOR]

Dental plaque is the principal etiological agent for the development and progression of gingival and periodontal diseases. Three different mouthwash types were compared in this study for the periodontal healing process based on the results. For all bacterial strains, the culture type collection is used. The serial dilution process is used for preparing every mouthwash and adding it to the tubes with a specific dilution. In certain microorganisms of the respective mouthwash, the last tube dilution that does not show any turbidity will be considered MIC. The three types of mouthwashes were compared in terms of the ability to inhibit microbial growth. Twenty-four hours after the agar was solidified and the colony forms (CFU) units counted, the plates were incubated. This study showed that bacterial growth inhibition might occur in the three types of mouthwash. Boht, Behsa and Kin-gingival mouthwashes had a significant difference in their antimicrobial effect. This study showed that they were unable to perform s after 24 hours of in vitro incubation while the bacterial count was lowered after two weeks of in vivo use in the boht washings. Continuous exposure to bacteria may be necessary to wash the mouth, especially for Behsa and Boht. It is difficult to remove all bacteria from the mechanical plaque controls; antibacterial mouthwash can cause additive. In the current study, three types of mouthwash have compared antimicrobial effects. The results showed only that bacterial counts are affected by mouthwash. Based on this study's results, Boht mouthwash is more effective than Kin Gingival and Behsa mouthwash for oral microorganisms, but further clinical studies are necessary to confirm our findings. [ABSTRACT FROM AUTHOR]

Dagaa fish hydrolysate (DFH) and dagaa protein hydrolysate (DPH) were prepared from dagaa using Alcalase enzyme. Proximate, mineral analysis, and potential use of DFH and DPH in microbial media were evaluated. Dagaa media formulations were used to culture bacteria commonly used for amylase production (Bacillus subtilis and Rhodobacter capsulatus) and that used as a bio-pesticide (Metarhizium anisopliae). Whole dagaa had the highest protein (5.2 ± 0.1 mg/ml), ash (13.5 ± 0.4%) and fat (2.36 ± 0.2%) content, while DPH had the least protein (2.6 ± 0.0 mg/ml) content. Mineral content was significantly different (p < 0.05) between dagaa and its hydrolysates. Dagaa and LB had the highest Sodium (22.7 ± 1.1 mg/ml) and calcium (0.3 ± 0.0 mg/ml), content respectively. Sustenance of amylase production in DPH-starch and standard media by both microorganisms was significantly different (p < 0.05). Sporulation rate of M. anisopliae in experimental media was not significant (p ˃ 0.05). [ABSTRACT FROM AUTHOR]

The use of irradiation alone as a preservation technique will not solve the problems of post-harvest food losses but it can play an important role in cutting losses in many cases when used judiciously along with good packaging. Hence, the study was planned to irradiate the foxtail millet flour at 1.5 kGy (IR) and stored in different packaging materials (LDPE, PP, PET and MPP) for a period of three months by taking flour stored without irradiation in steel box as control. Set of flour packed in different packaging materials (LDPE, PP, PET and MPP) without irradiation served as non-irradiated sample (NIR). Every fortnight the samples in three different treatments were drawn for biochemical changes (moisture, peroxide value and FFA), insect infestation and microbial growth. Significantly higher increase of moisture, peroxide value and FFA content was noticed in control sample followed by non irradiated PP and LDPE packed flour. Insect infestation started after 30 and 45 days of storage in steel boxes and non irradiated PP, LDPE covers, respectively, while no infestation of insects in case of MPP and PET packed flour. Further, significantly less biochemical changes (moisture, peroxide value and FFA) without fungal growth was noticed in irradiated MPP and PET packed samples. Thus, the foxtail millet flour stored in MPP and PET pouches with irradiation dose of 1.5 kGy was found suitable for safe storage up to three months under room temperature. [ABSTRACT FROM AUTHOR]

Composting process of residual organic material generates considerable amounts of liquid leachate which contains high organic load. This waste stream can be considered as potential nutrient source to support microbial growth. In the present work, the utilization of compost leachate as fermentation substrate for Bacillus species production was studied. The physicochemical properties of the leachate and two co-substrates (residual yeast and whey permeate) were determined. The characterization of leachate showed that it is a potential source of carbon, but its nitrogen content may limit the bacterial growth. In order to determine a good recipe of culture medium for fermentation of individual strains of Bacillus species, leachate was added with yeast and whey permeate. Raw and diluted leachates with and without amendments were tested in shake-flask fermentation assays. Results showed that Bacillus sp. grew better in diluted leachate than in raw leachate. When co-substrates were added, the growth was improved and the sporulation rate also increased. Since the aim was to produce plant growth–promoting bacteria, one of the objectives of fermentation assays was the production of viable bacteria when Bacillus sp. arrives to soil as component of a fertilizer. For this reason, the obtention of sporulated Bacillus cells was desired. The highest sporulation rate was obtained with co-substrates, inducing more than 89% of vegetative cells to develop spores. This approach of leachate valorization will produce economical benefits reducing the volume of leachate waste to be treated, as well as contribute in a cost-effective production of biological amendments in a circular economy mode. [ABSTRACT FROM AUTHOR]

Diauxie is at the origin of research that led Jacques Monod (1910–1976), François Jacob (1920–2013), and André Lwoff (1902–1994) to win the Nobel Prize in Physiology or Medicine in 1965 for their description of the first genetic regulatory model. Diauxie is a term coined by Jacques Monod in 1941 in his doctoral dissertation that refers to microbial growth in two phases. In this article, we first examine Monod's thesis to demonstrate how and why Monod interpreted diauxie as a phenomenon of enzyme inhibition or suppression of adaptive enzymes. We also briefly investigate prior enzyme suppression studies, before Monod's work, which indicate that he is the first person to observe diauxic growth. Second, we analyse Monod's post-thesis publications throughout his scientific career, revealing that diauxic inhibition was a significant part of Monod's scientific activities and greatly fascinated Monod until the end of his life. Paradoxically, Monod's work and interest on diauxic inhibition are still neglected in historical recounts, focused mostly on Monod's enzymatic adaptation studies. Indeed, we uncovered a statement by Monod's colleague, Lwoff, who transformed a quotation from Monod by replacing the word phenomenon with enzymatic adaptation, which we believe has influenced historians. Finally, we offer hypotheses to explain why Lwoff altered Monod's statement. [ABSTRACT FROM AUTHOR]

Currently, we assist the emergence of sensors and low-cost information and communication technologies applied to food products, in order to improve food safety and quality along the food chain. Thus, it is relevant to implement predictive mathematical modeling tools in order to predict changes in the food quality and allow decision-making for expiration dates. To perform that, the Baranyi and Roberts model and the online tool Combined Database for Predictive Microbiology (Combase) were used to determine the factors that define the growth of different bacteria. These factors applied to the equation that determines the maximum specific growth rate establish a relation between the bacterial growth and the intrinsic and extrinsic factors that define the bacteria environment. These models may be programmed in low-cost wireless biochemical sensor devices applied to packaging and food supply chains to promote food safety and quality through real time traceability. [ABSTRACT FROM AUTHOR]

Soil improvement techniques have been developed experimentally and empirically from various geotechnical standpoints based on physical, chemical, and biological findings. The traditional microbiological perspectives consider microbially induced soil cementation as an environment-friendly soil improvement technique. In particular, microbially induced carbonate precipitation (MICP) is recognised as an effective method with applications in real geotechnical problems. Traditionally, highly active species with carbonate-precipitating and their optimum environmental conditions have been identified through laboratory experiments and field surveys. Recently, numerical simulations considering microbial metabolic reactions have been tried for elucidating MICP. However, the mathematical and numerical evaluation of the relationship between bacterial growth and MICP requires further investigation. This study proposed a novel numerical simulation scheme for evaluating the effects of bacterial growth on stress distribution in soil micro- and macro-structure. In particular, this scheme utilised a reaction–diffusion system to determine bacterial growth and MICP in micro-structures. Further, stress and strain distributions in multi-scale structures were evaluated by a homogenisation method. Consequently, the simulation results of the calcium carbonate precipitation were 0.85–4.5 μmol/mm3 at 10.3 h. Evidently, the model values are reasonably consistent with the experimental data. Further, the homogenisation simulations indicated that soil stabilisation could be attributed to the formation of a novel skeleton structure comprising soil particles and calcium carbonate-filled soil pores. [ABSTRACT FROM AUTHOR]

The initial cyanide (CN−) concentration and amount of co-contaminants in GCTs can inhibit bacterial growth and reduce the CN−-degrading ability of bacteria. Several microorganisms can biotransform a wide range of organic and inorganic industrial contaminants into nontoxic compounds. However, active enzymatic CN− metabolism processes are mostly constrained by the physical and chemical characteristics of GCTs. High concentrations of toxic metal co-contaminants, such as, Pb, and Cr, and factors, such as pH, temperature, and oxygen concentration create oxidative stress and limit the CN−-degrading potential of cyanotrophic strains. The effects of such external and internal factors on the CN−-degrading ability of bacteria hinder the selection of suitable microorganisms for CN− biodegradation. Therefore, understanding the effects of the physicochemical properties of GCTs on cyanobacteria strains can help identify suitable microbes and favorable environmental conditions to promote microbial growth and can also help design efficient CN− biodegradation processes. In this review, we present a detailed analysis of the physicochemical properties of GCTs and their effects on microbial CN− degradation. [ABSTRACT FROM AUTHOR]

Highly concentrated sugar solutions are known to be effective antimicrobial agents. However, it is unknown whether this effect is solely the result of the collective osmotic effect imparted by a mixture of sugars or whether the type of carbohydrate used also has an individual chemical effect on bacterial responses, that is, inhibition/growth. In view of this, in this work, the antimicrobial properties of four sugars, namely, glucose, fructose, sucrose and maltose against three common food pathogens; Staphylococcus aureus, Escherichia coli and Salmonella enterica, were investigated using a turbidimetric approach. The results obtained indicate that the type of sugar used has a significant effect on the extent of bacterial inhibition which is not solely dependent on the water activity of the individual sugar solution. In addition, while it was shown that high sugar concentrations inhibit bacterial growth, very low concentrations show the opposite effect, that is, they stimulate bacterial growth, indicating that there is a threshold concentration upon which sugars cease to act as antimicrobial agents and become media instead. Significance and Impact of the Study: In this work, an analysis on the antimicrobial properties of glucose, fructose, sucrose and maltose in solution was conducted using a turbidimetric approach. Our findings indicate that while, as expected, all of these sugars exhibit significant antimicrobial effects at high concentrations, at low concentrations they appear to act as substrates for the bacteria which results in enhanced microbial growth instead of inhibition. In addition, the results obtained also suggest that the resultant osmotic stress imparted by the sugar solutions is not the only factor which determines their antimicrobial activity and that other chemical factors may be playing a significant role. [ABSTRACT FROM AUTHOR]

Resuspension of microbes in floor dust and subsequent inhalation by human occupants is an important source of human microbial exposure. Microbes in carpet dust grow at elevated levels of relative humidity, but rates of this growth are not well established, especially under changing conditions. The goal of this study was to model fungal growth in carpet dust based on indoor diurnal variations in relative humidity utilizing the time‐of‐wetness framework. A chamber study was conducted on carpet and dust collected from 19 homes in Ohio, USA and exposed to varying moisture conditions of 50%, 85%, and 100% relative humidity. Fungal growth followed the two activation regime model, while bacterial growth could not be evaluated using the framework. Collection site was a stronger driver of species composition (P = 0.001, R2 = 0.461) than moisture conditions (P = 0.001, R2 = 0.021). Maximum moisture condition was associated with species composition within some individual sites (P = 0.001‐0.02, R2 = 0.1‐0.33). Aspergillus, Penicillium, and Wallemia were common fungal genera found among samples at elevated moisture conditions. These findings can inform future studies of associations between dampness/mold in homes and health outcomes and allow for prediction of microbial growth in the indoor environment. [ABSTRACT FROM AUTHOR]

Phenotypic plasticity is the capacity to change the phenotype in response to different environments without alteration of the genotype. Despite sufficient evidence that microorganisms have a major role in the fitness and sickness of eukaryotes, there has been little research regarding microbial phenotypic plasticity. In this study, 45 strains of Staphylococcus aureus were grown for 12 days in both monoculture and in coculture with the same strain of Escherichia coli to create a competitive environment. Cell abundance was determined by quantitative PCR every 24 h, and growth curves of each S. aureus strain under the two sets of conditions were generated. Combined with whole-genome resequencing data, bivariate genome-wide association study (GWAS) was performed to analyze the growth plasticity of S. aureus in coculture. Finally, 20 significant single-nucleotide polymorphisms (eight annotated, seven unannotated, and five non-coding regions) were obtained, which may affect the competitive growth of S. aureus. This study advances genome-wide bacterial growth plasticity research and demonstrates the potential of bivariate GWAS for bacterial phenotypic plasticity research. Key Points: • Growth plasticity of S. aureus was analyzed by bivariate GWAS. • Twenty significant SNPs may affect the growth plasticity of S. aureus. [ABSTRACT FROM AUTHOR]

Quartz crystal microbalance (QCM) sensors are becoming a good alternative to analytical methods for the measurement of bacterial growth in liquid media culture. For this purpose, two essential resonance parameters allow the monitoring of biofilm formation: the series resonance frequency shift and the change of the resistance at this frequency. Nevertheless, several problems arise in determining these parameters, as their relative variation is very small. This means that an accurate procedure must be implemented for the measurement of the QCM resonance parameters, including the automatic calibration of the frequency response effects of the measurement circuits and the automatic compensation of the static electrical capacitance of the QCM. In this article, a novel multichannel system for on-line monitoring of biofilm formation based on QCM sensors is proposed. QCM resonance parameters are determined from the electrical impedance analysis by means of an auto-balanced impedance bridge. This configuration has allowed the implementation of an affordable multichannel measurement instrument. Obtained results, based on binary mixtures of water–glycerol measurements and real microorganism experiments, are in good agreement with the theoretical behavior. These results show the great potential of this instrument to be used for monitoring microbial growth and biofilm formation. [ABSTRACT FROM AUTHOR]

We report the calcium isotope fractionation during the microbially-induced precipitation of calcium carbonate minerals in pure cultures of the marine sulfate-reducing bacterium Desulfovibrio bizertensis. These data are used to explore how the calcium isotope fractionation factor during microbially-induced carbonate mineral precipitation differs from the better-constrained calcium isotope fractionation factors during biogenic or abiotic carbonate mineral precipitation. Bacterial growth was then modulated with antibiotics, and the evolution of δ44Ca in solution was monitored under different microbial growth rates. The faster the microbial growth rate, the larger the calcium isotope fractionation during carbonate mineral precipitation, with Δ44Ca (s-f) ranging from −1.07‰ to −0.48‰. The reported calcium isotope fractionation can help us understand the link between calcium isotope fractionation and microbial metabolism in carbonate minerals precipitated during sedimentary diagenesis. [ABSTRACT FROM AUTHOR]

Background: This research was planned to search for a potential of modified hydrothermal nanotitania extract in inhibiting the growth of bacteria commonly known in medical field. It is also aims to test this substance against common medical bacteria,Escherichia coli. Materials and methods: In this test, suspension of modified hydrothermal nanotitania extract (together with 0.01%, 0.03% and 0.05% silver) and undoping (positive control contains TiO2 and no silver) were prepared by mixing of TiO2 in Mueller Hinton Broth (MH) agar. The platecontaining the bacteria and TiO2 were observed after 24 hour, 48 hours and 72 hours incubation at 37°C for any growth of bacteria. Results: There was no growth of Escherichia coliin the plates containing the bacteria and modified hydrothermal nanotitania extract except in the control media. Conclusions: The finding suggested the modified hydrothermal nanotitania extractioninterfered the growth of Escherichia coli. [ABSTRACT FROM AUTHOR]

The study aims to check the antimicrobial effect of soft drinks on gut bacteria. A soft drink is a drink that usually contains carbonated water, a sweetener, and a natural or artificial flavouring. The sweetener may be a sugar, high- fructose corn syrup, fruit juice, sugar substitute, or some combination of these. In non-carbonated drinks, preservatives are added to increase the shelf life. The preservative is a substance or a chemical that is added to food or beverages to prevent decomposition due to microbial growth or any other undesirable chemical changes, mainly to prevent bacterial growth. This may affect the bacteria present in the mouth and even in the intestine. Normal flora is a set of microorganisms that live on a host without causing any disease. They become the resident flora of our body. They are called commensals. These bacteria prevent us from being affected by more dangerous bacteria. It is essential to protect our body against the injurious agents. These soft drinks are not at all beneficial to us in any way. The normal flora of our body is very essential to maintain our normal health. Loss of normal flora will lead to colonisation of pathogens in our mouth and intestine. [ABSTRACT FROM AUTHOR]

Listeria monocytogenes causes the severe foodborne illness listeriosis and survives in food-associated environments due to its high stress tolerance. A data assembly and analysis protocol for microbial growth experiments was compiled to elucidate the strain variability of L. monocytogenes stress tolerance. The protocol includes measurement of growth ability under stress (step 1), selection of a suitable method for growth parameter calculation (step 2), comparison of growth patterns between strains (step 3), and biological interpretation of the discovered differences (step 4). In step 1, L. monocytogenes strains (n=388) of various serovars and origins grown on media with 9.0% NaCl were measured using a Bioscreen C microbiology reader. Technical variability of the growth measurements was assessed and eliminated. In step 2, the growth parameters determined by Gompertz, modified- Gompertz, logistic, and Richards models and model-free splines were compared, illustrating differences in the suitability of these methods to describe the experimental data. In step 3, hierarchical clustering was used to describe the NaCl tolerance of L. monocytogenes measured by strain-specific variation in growth ability; tolerant strains had higher growth rates and maximum optical densities and shorter lag phases than susceptible strains. The spline parameter area under the curve best classified "poor," "average," and "good" growers. In step 4, the tested L. monocytogenes lineage I strains (serovars 4b and 1/2b) proved to be significantly more tolerant toward 9.0% NaCl than lineage II strains (serovars 1/2a, 1/2c, and 3a). Our protocol provides systematic tools to gain comparable data for investigating strain-specific variation of bacterial growth under stress. [ABSTRACT FROM AUTHOR]

This comparative study was carried out to investigate the effect of nanosilver, silver-clay nanohybrid, and silver-milled clay nanohybrid coatings on the antibacterial characteristics of paper. Nanosilver (25 ppm) was used as a single-and double-layer coating. The results demonstrated that treatment with pure nanosilver was more efficient in the reduction of microbial growth. Also, milling of clay enabled better maintenance of silver nanoparticles, and led to a greater decrease in bacterial growth than in the case of the original silver-clay nanohybrid. Evaluation of the sustainability of antibacterial characteristics confirmed that, although pure nanosilver treatment achieved better performance in the first 15 minutes than nanohybrid samples, the performance of the nanohybrids improved with the passing of time. As expected, the treatments decreased the brightness of paper, while the opacity increased significantly; pure nanosilver treatment led to lower brightness than the others, and the opacity was higher in the case of the silver-clay nanohybrid than with the other treatments. [ABSTRACT FROM AUTHOR]

Plant essential oils and extracts are the compounds that can inhibit bacterial growth at low concentrations. Also, these materials are mostly strong antioxidants and the presence of these two properties together increases the shelf-life of fish. This study was done to investigate effect of various concentrations of caraway and thyme essences on chemical and microbial quality of common carp fillet. Different concentrations of essential oils (0, 500, 1000 and 2000 mg/l) were added to fish samples and some chemical and oxidation factors, microbial quality and sensory properties of the samples were determined. The results showed the lowest levels of total volatile basic nitrogen was related to 2000 mg/l thyme essential oil (24.6 mg/100 g fillet) and the highest amount of total volatile basic nitrogen were observed in control treatment (75.11 mg/ 100g fillet) at refrigerator temperature. TBA levels in all treatments increased with increasing storage time and at the end of the storage period, except in 500 and 1000 mg/l thyme essences treatments, there was significant difference among all experimental samples (p<0.05). The results showed that various concentrations of essences reduced the total count and Psychrotrophic bacteria compared to the control. At the end of the storage time, treatment of 2000 mg/l caraway essence, 1000 mg/l caraway essence and 2000 mg/l thyme essence had the lower Psychrotrophic bacteria than the other samples. Treatments with 1000 and 2000 mg/l caraway essences in freezing conditions received the most colors score. The highest score of texture was related to 2000 mg/l thyme essential oil at refrigerator temperature. Samples containing 1000 mg/l caraway essence in freezing temperatures had the highest odor score. In general, 1000 and 2000 mg/l concentrations of thyme essence due to acceptance of the organoleptic characteristics from the consumer view as well as reduce microbial growth and chemical factors are recommended. [ABSTRACT FROM AUTHOR]