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1.
J Appl Microbiol ; 2024 Oct 08.
Artículo en Inglés | MEDLINE | ID: mdl-39380147

RESUMEN

AIM: To investigate the effect of pyruvate and glucose on leucine transamination and 3-methylbutanal production by Lactococcus lactis, including the comparison with cells possessing glutamate dehydrogenase (GDH) activity. METHODS AND RESULTS: L. lactis cells were incubated in chemically defined medium (CDM) with the pH controlled at 5.2 to mimic cheese conditions. Pyruvate supplementation stimulated the production of the key flavour compound 3-methylbutanal by 3 to 4 times after 72 hours of incubation. Concurrently, alanine production increased, demonstrating the involvement of pyruvate in transamination reactions. Glucose-metabolising cells excreted α-ketoisocaproic acid and produced even 3 times more 3-methylbutanal after 24 hours than pyruvate-supplemented cells. Conjugal transfer technique was used to transfer the plasmid pGdh442 carrying the gdh gene encoding for GDH to L. lactis. Introducing GDH did not stimulate the excretion of α-ketoisocaproic acid and the production of 3-methylbutanal. CONCLUSIONS: These results demonstrate that Lactococcus uses pyruvate to transaminate leucine into α-ketoisocaproic acid which supports 3-methylbutanal production. Surprisingly, GDH activity did not stimulate leucine transamination and 3-methylbutanal production.

2.
Curr Res Insect Sci ; 6: 100092, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-39224195

RESUMEN

Standard metabolic rates (SMR) of ectotherms reflect the energetic cost of self-maintenance and thus provide important information about life-history strategies of organisms. We examined variation in SMR among fifteen species of New Zealand orthopteran. These species represent a heterogeneous group with a wide geographic distribution, differing morphologies and life histories. Gathering original data on morphological and physiological traits of individual species is a first step towards understanding existing variability. Individual metabolic rates of ectotherms are one of the first traits to respond to climate change. Baseline SMR datasets are valuable for modeling current species distributions and their responses to a changing climate. At higher latitudes, the average environmental temperature decreases. The pattern that cold-adapted ectotherms display higher SMR at colder temperatures and greater thermal sensitivity to compensate for lower temperatures and the shorter growing and reproductive seasons is predicted from the metabolic cold adaptation (MCA) hypothesis. We predict higher SMR for the orthopteran species found at higher latitudes. We further compared the index of thermal sensitivity Q10 per species. We used closed-system respirometry to measure SMR, at two test temperatures (4 °C and 14 °C), for the fifteen species acclimated to the same conditions. As expected, we found significant differences in SMR among species. The rate of oxygen consumption was positively correlated with body mass. Our findings do not support the MCA hypothesis. In fact, we found evidence of co-gradient variation in SMR, whereby insects from higher elevations and latitudes presented lower SMR. We discuss our findings in relation to life histories and ecology of each species. The novel physiological data presented will aid in understanding potential responses of these unusual species to changing climatic conditions in Aotearoa/New Zealand.

3.
Heliyon ; 10(13): e33444, 2024 Jul 15.
Artículo en Inglés | MEDLINE | ID: mdl-39027605

RESUMEN

Ethylene glycol (EG, 1,2-ethanediol) is a two-carbon dihydroxy alcohol that can be derived from fermentation of plant-derived xylose and arabinose and which can be formed during food fermentations. Here we show that Propionibacterium freudenreichii DSM 20271 is able to convert EG in anaerobic conditions to ethanol and acetate in almost equimolar amounts. The metabolism of EG led to a moderate increase of biomass, indicating its metabolism is energetically favourable. A proteomic analysis revealed EG induced expression of the pdu-cluster, which encodes a functional bacterial microcompartment (BMC) involved in the degradation of 1,2-propanediol, with the presence of BMCs confirmed using transmission electron microscopy. Cross-examination of the proteomes of 1,2-propanediol and EG grown cells revealed PDU BMC-expressing cells have elevated levels of DNA repair proteins and cysteine biosynthesis proteins. Cells grown in 1,2-propanediol and EG also showed enhanced resistance against acid and bile salt-induced stresses compared to lactate-grown cells. Our analysis of whole genome sequences of selected genomes of BMC-encoding microorganisms able to metabolize EG with acetaldehyde as intermediate indicate a potentially broad-distributed role of the pdu operon in metabolism of EG. Based on our results we conclude EG is metabolized to acetate and ethanol with acetaldehyde as intermediate within BMCs in P. freudenreichii.

4.
Curr Microbiol ; 81(7): 217, 2024 Jun 09.
Artículo en Inglés | MEDLINE | ID: mdl-38852107

RESUMEN

The application of enzymes in agricultural fields has been little explored. One potential application of fungal lytic enzymes (chitinases, lipases, and proteases) is as an additive to current biopesticides to increase their efficacy and reduce the time of mortality. For this, a screening of lytic overproducer fungi under submerged fermentation with a chemical-defined medium was performed. Then, the enzymatic crude extract (ECE) was concentrated and partially characterized. This characterization consisted of measuring the enzymatic activity (lipase, protease and, chitinase) and determining the enzyme stability after storage at temperatures of - 80, - 20 and, 4 °C. And lastly, the application of these concentrated enzymatic crude extracts (C-ECE) as an enhancer of spores-based fungal biopesticide was proven. Beauveria were not as good producers of lytic enzymes as the strains from Trichoderma and Metarhizium. The isolate M. robertsii Mt015 was selected for the co-production of chitinases and proteases; and the isolate T. harzianum Th180 for co-production of chitinases, lipases, and proteases. The C-ECE of Mt015 had a protease activity of 18.6 ± 1.1 U ml-1, chitinase activity of 0.28 ± 0.01 U ml-1, and no lipase activity. Meanwhile, the C-ECE of Th180 reached a chitinase activity of 0.75 U ml-1, lipase activity of 0.32 U ml-1, and protease activity of 0.24 U ml-1. Finally, an enhancing effect of the enzymatic extracts of M. robertsii (66.7%) and T. harzianum (43.5%) on the efficacy of B. bassiana Bv064 against Diatraea saccharalis larvae was observed. This work demonstrates the non-species-specific enhancing effect of enzymatic extracts on the insecticidal activity of conidial-based biopesticides, which constitutes a contribution to the improvement of biological control agents' performance.


Asunto(s)
Quitinasas , Fermentación , Péptido Hidrolasas , Quitinasas/metabolismo , Péptido Hidrolasas/metabolismo , Animales , Lipasa/metabolismo , Proteínas Fúngicas/metabolismo , Proteínas Fúngicas/genética , Agentes de Control Biológico/farmacología , Agentes de Control Biológico/metabolismo , Hongos/metabolismo , Control Biológico de Vectores/métodos , Beauveria/enzimología , Beauveria/metabolismo , Estabilidad de Enzimas
5.
J Environ Qual ; 2024 May 30.
Artículo en Inglés | MEDLINE | ID: mdl-38816346

RESUMEN

The Lower Mississippi River Basin-Long-Term Agroecosystem Research Site (LMRB-LTAR) encompasses six states from Missouri to the Gulf of Mexico and is coordinated by the USDA-ARS National Sedimentation Laboratory, Oxford, MS. The overarching goal of LTAR is to assess regionally diverse and geographically scalable farming practices for enhanced sustainability of agroecosystem goods and services under changing environment and resource-use conditions. The LMRB-LTAR overall goal is to assess sustainable row crop agricultural production systems that integrate regional environmental and socioeconomic needs. Primary row crops in the region include soybeans, corn, cotton, rice, and sugarcane with crop rotations influenced by commodity crop price and other factors. The field-scale common experiment (CE) includes four row crop farms (26-101 ha) established in 2021 and 2023. Three fields are managed with alternative practices, including reduced tillage, cover crops, and automated prescription irrigation, and three fields are managed with prevailing farming practices, consisting of conventional tillage, no cover crop, and nonprescription irrigation. Treatment effects on crop productivity, soil quality, water use efficiency, water quality, and carbon storage are assessed. Research from the LMRB CE will deliver outcomes linked to overarching LTAR network goals, including innovative agricultural systems, strengthened partnerships, data management technologies, and precision environmental tools.

6.
Dev Psychopathol ; : 1-14, 2024 Apr 24.
Artículo en Inglés | MEDLINE | ID: mdl-38654407

RESUMEN

This study aimed to parse between-person heterogeneity in growth of impulsivity across childhood and adolescence among participants enrolled in five childhood preventive intervention trials targeting conduct problems. In addition, we aimed to test profile membership in relation to adult psychopathologies. Measurement items representing impulsive behavior across grades 2, 4, 5, 7, 8, and 10, and aggression, substance use, suicidal ideation/attempts, and anxiety/depression in adulthood were integrated from the five trials (N = 4,975). We applied latent class growth analysis to this sample, as well as samples separated into nonintervention (n = 2,492) and intervention (n = 2,483) participants. Across all samples, profiles were characterized by high, moderate, low, and low-increasing impulsive levels. Regarding adult outcomes, in all samples, the high, moderate, and low profiles endorsed greater levels of aggression compared to the low-increasing profile. There were nuanced differences across samples and profiles on suicidal ideation/attempts and anxiety/depression. Across samples, there were no significant differences between profiles on substance use. Overall, our study helps to inform understanding of the developmental course and prognosis of impulsivity, as well as adding to collaborative efforts linking data across multiple studies to better inform understanding of developmental processes.

7.
Cell Host Microbe ; 32(4): 506-526.e9, 2024 Apr 10.
Artículo en Inglés | MEDLINE | ID: mdl-38479397

RESUMEN

To understand the dynamic interplay between the human microbiome and host during health and disease, we analyzed the microbial composition, temporal dynamics, and associations with host multi-omics, immune, and clinical markers of microbiomes from four body sites in 86 participants over 6 years. We found that microbiome stability and individuality are body-site specific and heavily influenced by the host. The stool and oral microbiome are more stable than the skin and nasal microbiomes, possibly due to their interaction with the host and environment. We identify individual-specific and commonly shared bacterial taxa, with individualized taxa showing greater stability. Interestingly, microbiome dynamics correlate across body sites, suggesting systemic dynamics influenced by host-microbial-environment interactions. Notably, insulin-resistant individuals show altered microbial stability and associations among microbiome, molecular markers, and clinical features, suggesting their disrupted interaction in metabolic disease. Our study offers comprehensive views of multi-site microbial dynamics and their relationship with host health and disease.


Asunto(s)
Estabilidad Central , Microbiota , Humanos , Piel/microbiología , Interacciones Microbiota-Huesped , Biomarcadores
8.
Heliyon ; 10(5): e26849, 2024 Mar 15.
Artículo en Inglés | MEDLINE | ID: mdl-38463896

RESUMEN

Natto is a traditional Japanese fermented product consisting of cooked soybeans fermented with Bacillus subtilis var. natto. We assessed three different B. subtilis strains and investigated their impact on product quality aspects, such as microbial quality, textural quality (poly-γ-glutamate strand formation), free amino acids (FAA), and volatile organic compounds (VOCs), but also the vitamin K1, K2 and B1 content, and presence of nattokinase. Using Bayesian contrast analysis, we conclude that the quality attributes were influenced by both the substrate and strain used, without significant differences in bacterial growth between strain or substrate. Overall, all the tested European legumes, except for brown beans, are adequate substrates to produce natto, with comparable or higher qualities compared to the traditional soy. Out of all the tested legumes, red lentils were the most optimal fermentation substrate. They were fermented most consistently, with high concentrations of vitamin K2, VOCs, FAA.

9.
FEMS Microbiol Lett ; 3712024 Jan 09.
Artículo en Inglés | MEDLINE | ID: mdl-38479791

RESUMEN

Lactic acid bacteria (LAB) have evolved into fastidious microorganisms that require amino acids from environmental sources. Some LAB have cell envelope proteases (CEPs) that drive the proteolysis of high molecular weight proteins like casein in milk. CEP activity is typically studied using casein as the predominant substrate, even though CEPs can hydrolyze other protein sources. Plant protein hydrolysis by LAB has rarely been connected to the activity of specific CEPs. This study aims to show the activity of individual CEPs using LAB growth in a minimal growth medium supplemented with high molecular weight casein or potato proteins. Using Lactococcus cremoris MG1363 as isogenic background to express CEPs, we demonstrate that CEP activity is directly related to growth in the protein-supplemented minimal growth media. Proteolysis is analyzed based on the amino acid release, allowing a comparison of CEP activities and analysis of amino acid utilization by L. cremoris MG1363. This approach provides a basis to analyze CEP activity on plant-based protein substrates as casein alternatives and to compare activity of CEP homologs.


Asunto(s)
Lactococcus lactis , Péptido Hidrolasas , Animales , Péptido Hidrolasas/metabolismo , Caseínas/metabolismo , Peso Molecular , Endopeptidasas/química , Lactococcus lactis/metabolismo , Aminoácidos/metabolismo
10.
Int J Food Microbiol ; 416: 110683, 2024 May 02.
Artículo en Inglés | MEDLINE | ID: mdl-38554557

RESUMEN

Traditionally fermented maize starch, called ogi, is produced to prepare akpan, a yoghurt-like street food widely consumed in Benin. Current maize ogi production practices were compared to assess the impact of different processing technologies on the characteristics of the fermented product as a basis to determine best practices. Maize starch slurry samples were collected from processors in five municipalities in southern Benin and analysed before fermentation (starch samples) and after spontaneous fermentation (ogi samples). Four technological pathways for maize starch production were distinguished based on variations in the duration of steeping the grains, which ranged from 6 to 72 h, and whether or not kneading of the wet flour before filtration was practised. Six categories of maize ogi were derived from the four technology groups based on the duration of the fermentation, which lasted from 6 to 24 h. The average pH of maize starch varied from 3.2 to 5.3, with the lowest values for the two technology groups that also had the highest lactate concentrations (9-11.8 g/L). The six maize ogi categories had a pH ranging from 3.1 to 4.0. Viable plate counts of lactic acid bacteria were similar for maize starch samples and for ogi samples, whereas yeast counts showed clear differences. Members of the genera Limosilactobacillus, Lactobacillus, Weissella, Streptococcus and Ligilactobacillus, dominated the bacterial community in maize starch, and were also dominant in maize ogi. The members of the genera dominating the fungal community in maize starch were also dominant in maize ogi, except for Aspergillus and Stenocarpella spp., which decreased in relative abundance by fermentation. The highest total free essential amino acid concentration was 61.6 mg/L in maize starch and 98.7 mg/L in ogi. The main volatile organic compounds in maize starch samples were alcohols, esters, and carboxylic acids, which also prevailed in maize ogi samples. The results indicate that the characteristics of traditional maize ogi depend on the processing technologies used to produce the maize starch before the intentional fermentation into ogi, with no clear-cut connection with the production practices due to high variations between samples from the same technology groups. This revealed the importance of a standardized maize starch production process, which would benefit controlling the starch fermentation and the characteristics of maize ogi. Further research is needed to understand the hidden fermentation during maize starch production for determination of the best practices that support the production of quality maize ogi.


Asunto(s)
Microbiota , Zea mays , Zea mays/microbiología , Lactobacillus/metabolismo , Almidón , Saccharomyces cerevisiae/metabolismo , Fermentación
11.
bioRxiv ; 2024 Feb 01.
Artículo en Inglés | MEDLINE | ID: mdl-38352363

RESUMEN

To understand dynamic interplay between the human microbiome and host during health and disease, we analyzed the microbial composition, temporal dynamics, and associations with host multi-omics, immune and clinical markers of microbiomes from four body sites in 86 participants over six years. We found that microbiome stability and individuality are body-site-specific and heavily influenced by the host. The stool and oral microbiome were more stable than the skin and nasal microbiomes, possibly due to their interaction with the host and environment. Also, we identified individual-specific and commonly shared bacterial taxa, with individualized taxa showing greater stability. Interestingly, microbiome dynamics correlated across body sites, suggesting systemic coordination influenced by host-microbial-environment interactions. Notably, insulin-resistant individuals showed altered microbial stability and associations between microbiome, molecular markers, and clinical features, suggesting their disrupted interaction in metabolic disease. Our study offers comprehensive views of multi-site microbial dynamics and their relationship with host health and disease. Study Highlights: The stability of the human microbiome varies among individuals and body sites.Highly individualized microbial genera are more stable over time.At each of the four body sites, systematic interactions between the environment, the host and bacteria can be detected.Individuals with insulin resistance have lower microbiome stability, a more diversified skin microbiome, and significantly altered host-microbiome interactions.

12.
R Soc Open Sci ; 11(2): 231118, 2024 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-38356874

RESUMEN

The biota of continents and islands are commonly considered to have a source-sink relationship, but small islands can harbour distinctive taxa. The distribution of four monotypic genera of Orthoptera on young subantarctic islands indicates a role for long-distance dispersal and extinction. Phylogenetic relationships were inferred from whole mtDNA genomes and nuclear sequences (45S cassette; four histones). We used a fossil and one palaeogeographic event to calibrate molecular clock analysis. We confirm that neither the Australian nor Aotearoa-New Zealand Rhaphidophoridae faunas are monophyletic. The radiation of Macropathinae may have begun in the late Jurassic, but trans-oceanic dispersal is required to explain the current distribution of some lineages within this subfamily. Dating the most recent common ancestor of seven island endemic species with their nearest mainland relative suggests that each existed long before their island home was available. Time estimates from our fossil-calibrated molecular clock analysis suggest several lineages have not been detected on mainland New Zealand, Australia, or elsewhere most probably due to their extinction, providing evidence that patterns of extinction, which are not consistently linked to range size or lineage age, confound biogeographic signal.

13.
Carbohydr Polym ; 328: 121700, 2024 Mar 15.
Artículo en Inglés | MEDLINE | ID: mdl-38220337

RESUMEN

Soybean tempeh contains bioactive carbohydrate that can reduce the severity of diarrhea by inhibiting enterotoxigenic Escherichia coli (ETEC) adhesion to mammalian epithelial cells. Lactic acid bacteria (LAB) are known to be present abundantly in soybean tempeh. Some LAB species can produce exopolysaccharides (EPS) with anti-adhesion bioactivity against ETEC but there has been no report of anti-adhesion bioactive EPS from tempeh-associated LAB. We isolated EPS-producing LAB from tempeh-related sources, identified them, unambiguously elucidated their EPS structure and assessed the bioactivity of their EPS against ETEC. Pediococcus pentosaceus TL, Leuconostoc mesenteroides WA and L. mesenteroides WN produced both dextran (α-1,6 linked glucan; >1000 kDa) and levan (ß-2,6 linked fructan; 650-760 kDa) in varying amounts and Leuconostoc citreum TR produced gel-forming α-1,6-mixed linkage dextran (829 kDa). All four isolates produced EPS that could adhere to ETEC cells and inhibit auto-aggregation of ETEC. EPS-PpTL, EPS-LmWA and EPS-LmWN were more bioactive towards pig-associated ETEC K88 while EPS-LcTR was more bioactive against human-associated ETEC H10407. Our finding is the first to report on the bioactivity of dextran against ETEC. Tempeh is a promising source of LAB isolates that can produce bioactive EPS against ETEC adhesion and aggregation.


Asunto(s)
Escherichia coli Enterotoxigénica , Infecciones por Escherichia coli , Lactobacillales , Alimentos de Soja , Animales , Porcinos , Humanos , Dextranos/farmacología , Fructanos/farmacología , Infecciones por Escherichia coli/microbiología , Mamíferos
14.
Int J Food Microbiol ; 410: 110486, 2024 Jan 30.
Artículo en Inglés | MEDLINE | ID: mdl-37992553

RESUMEN

Listeria monocytogenes is a facultative anaerobe which can cause a severe food-borne infection known as listeriosis. L. monocytogenes is capable of utilizing various nutrient sources including rhamnose, a naturally occurring deoxy sugar abundant in foods. L. monocytogenes can degrade rhamnose into lactate, acetate and 1,2-propanediol. Our previous study showed that addition of vitamin B12 stimulated anaerobic growth of L. monocytogenes on rhamnose due to the activation of bacterial microcompartments for 1,2-propanediol utilization (pdu BMC) with concomitant production of propionate and propanol. Notably, anaerobic 1,2-propanediol metabolism has been linked to virulence of enteric pathogens including Salmonella spp. and L. monocytogenes. In this study we investigated the impact of B12 and BMC activation on i) aerobic and anerobic growth of L. monocytogenes on rhamnose and ii) the level of virulence. We observed B12-induced pdu BMC activation and growth stimulation only in anaerobically grown cells. Comparative Caco-2 virulence assays showed that these pdu BMC-induced cells have significantly higher translocation efficiency compared to non-induced cells (anaerobic growth without B12; aerobic growth with or without B12), while adhesion and invasion capacity is similar for all cells. Comparative proteome analysis showed specific and overlapping responses linked to metabolic shifts, activation of stress defense proteins and virulence factors, with RNA polymerase sigma factor SigL, teichoic acid export ATP-binding protein TagH, DNA repair and protection proteins, RadA and DPS, and glutathione synthase GshAB, previously linked to activation of virulence response in L. monocytogenes, uniquely upregulated in anaerobically rhamnose grown pdu-induced cells. Our results shed light on possible effects of B12 on L. monocytogenes competitive fitness and virulence activation when utilizing rhamnose in anaerobic conditions encountered during transmission and the human intestine.


Asunto(s)
Listeria monocytogenes , Listeriosis , Humanos , Ramnosa/metabolismo , Células CACO-2 , Propilenglicol/metabolismo , Virulencia/genética , Vitamina B 12/farmacología , Vitamina B 12/metabolismo , Listeriosis/microbiología , Vitaminas/metabolismo , Proteínas Bacterianas/genética
15.
J Interpers Violence ; 39(9-10): 2290-2317, 2024 May.
Artículo en Inglés | MEDLINE | ID: mdl-38158738

RESUMEN

Fear of victimization (FOV) is a powerful determinant of behavior and prompts behavioral responses such as avoidance, associated with a decline in health-promoting activities and quality of life. Avoidance behaviors, which include constraining activities to perceived safe areas and avoiding areas regarded as unsafe, are of particular interest due to their high prevalence as a coping response to FOV and their link to adverse physical and mental health. Most research on FOV-related avoidance treats it as a single construct and have yet to elucidate the potential heterogeneity within this set of behaviors. We argue that such approach could mask potential heterogeneity among people who respond to FOV through avoidance and how they adapt to manage perceived risk. Our analysis extends the foundational knowledge regarding FOV-related avoidance using a person-centered approach. We attempted to capture distinct profiles across avoidance behaviors and how they are shaped by physical and social vulnerabilities. Data from the 2021 Mexico's National Survey of Victimization and Perception of Security Survey (n = 83,696) was analyzed using Latent Class Analysis focusing on 15 avoidance behaviors (e.g., stopped using public transportation). We conducted multinomial logistic regression to test whether age, gender, education, and neighborhood deprivation significantly predicted class membership. Findings revealed three classes: avoidant (most behavioral adjustments across the board), cautious (only adapted some behaviors), and protective (least behavioral adjustments, but more concerned about minors in their households). The results supported the hypothesized associations between age, gender, education, and neighborhood deprivation with group membership, but the significance differed by group. This research underscores the role of environmental context in shaping individual perceptions of safety and avoidance behavior. Finally, contrary to the approach of treating avoidance behavior as a single category, these findings present a more complex picture as distinct and meaningful patterns emerged across the three groups.


Asunto(s)
Reacción de Prevención , Víctimas de Crimen , Humanos , Análisis de Clases Latentes , México , Calidad de Vida , Víctimas de Crimen/psicología , Miedo
16.
Microbiome Res Rep ; 2(4): 33, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-38045922

RESUMEN

Background: Lytic bacteriophages infect and lyse bacteria and, as a by-product, may affect diversity in microbial communities through selective predation on abundant bacterial strains. We used a complex dairy starter named Ur to investigate population dynamics of Lactococcus lactis, Lactococcus cremoris and Leuconostoc mesenteroides strains in terms of constant-diversity and periodic selection models. Methods: To mimic the starter Ur, we designed blends of 24 strains representing all eight previously identified genetic lineages in the starter culture. The blends were propagated by daily transfers in milk for over 500 generations in the presence or absence of a cocktail of lytic bacteriophages. The relative abundance of genetic lineages of L. lactis, L. cremoris and Lc. mesenteroides strains present in the complex blend, as well as phage presence, were monitored. Results: Control blends without phage predation showed decreased strain diversity, leading to a stable state due to the domination of the fittest strain(s) of a particular lineage according to periodic selection dynamics. However, in phage-challenged blends, predation caused a large shift in the microbial composition by killing the fittest and sensitive strains. Conclusion: It was demonstrated that phage-challenged blends maintained their diversity at the level of genetic lineages, thus providing experimental support for the constant-diversity dynamics model in a complex microbial community.

17.
Yeast ; 40(12): 628-639, 2023 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-37930115

RESUMEN

Vitamin B1 , also known as thiamine, is an important vitamin that, besides its role in human health, is converted to meat aromas upon exposure to high temperatures. Therefore, it is relevant for the production of vegan meat-like flavours. In this study, we investigated 48 Saccharomyces cerevisiae strains for their thiamine production capacity by measuring the intracellular and extracellular vitamins produced in the thiamine-free minimal medium after 72 h of growth. We found approximately an 8.2-fold difference in overall thiamine yield between the highest and lowest-producing strains. While the highest thiamine yield was 254.6 nmol/L, the highest thiamine-specific productivity was 160.9 nmol/g DW. To assess whether extracellular thiamine was due to leakage caused by cell damage, we monitored membrane permeabilization using propidium iodide (PI) staining and flow cytometry. We found a good correlation between the percentage of extracellular thiamine and PI-stained cells (Spearman's ρ = 0.85). Finally, we compared S. cerevisiae CEN.PK113-7D (wild type [WT]) to three strains evolved in a thiamine-free medium for their thiamine production capacity. On average, we saw an increase in the amount of thiamine produced. One of the evolved strains had a 49% increase in intracellular thiamine-specific productivity and a biomass increase of 20% compared with the WT. This led to a total increase in thiamine yield of 60% in this strain, reaching 208 nmol/L. This study demonstrated that it is possible to achieve thiamine overproduction in S. cerevisiae via strain selection and adaptive laboratory evolution.


Asunto(s)
Proteínas de Saccharomyces cerevisiae , Saccharomyces cerevisiae , Humanos , Saccharomyces cerevisiae/metabolismo , Tiamina , Proteínas de Saccharomyces cerevisiae/metabolismo , Vitaminas
18.
N Biotechnol ; 78: 123-130, 2023 Dec 25.
Artículo en Inglés | MEDLINE | ID: mdl-37879567

RESUMEN

End-product inhibition in pH-controlled batch cultures, is the major limiting factor for bacterial biomass formation in the starter culture industry as well as in many other biotechnological processes. Adaptive laboratory evolution (ALE) has emerged over the past decades as a powerful tool for phenotype optimization, but none of the existing ALE methods could select for improved end-product resistance. Therefore, we developed the stressostat (STress Resistance Evolution in Substrate Surplus) as a novel continuous ALE method. Stressostat cultivation applies end-product concentrations as constant evolutionary pressure on microorganisms in the presence of substrate surplus. In this study, we improved the lactate resistance of Lactococcus lactis FM03P in 35 days of stressostat cultivations. The lactate concentrations increased over time from 530 to 675 mM, indicating the successful selection for variants with improved lactate resistance. Thirty-four variants were isolated and grouped into four clusters based on their growth rates at high lactate concentrations. In the high-throughput screening without pH control, most isolated variants could grow at high lactate concentrations (870-928 mM), while the wild type was completely inhibited. The variants grew slower than wild type at low lactate media indicating possible evolutionary trade-off. However, in pH-controlled batch cultivations, most variants produced more biomass than the wild type. In conclusion, stressostat cultivation is a valuable method to obtain L. lactis variants with improved end-product resistance and further characterization is needed to elucidate underlying resistance mechanisms and potential industrial applications.


Asunto(s)
Técnicas de Cultivo Celular por Lotes , Ácido Láctico , Ácido Láctico/farmacología
19.
FEMS Microbiol Ecol ; 99(10)2023 09 19.
Artículo en Inglés | MEDLINE | ID: mdl-37771082

RESUMEN

The influence of community diversity, which can be measured at the level of metabolic guilds, on community function is a central question in ecology. Particularly, the long-term temporal dynamic between a community's function and its diversity remains unclear. We investigated the influence of metabolic guild diversity on associated community function by propagating natural microbial communities from a traditionally fermented milk beverage diluted to various levels. Specifically, we assessed the influence of less abundant microbial types, such as yeast, on community functionality and bacterial community compositions over repeated propagation cycles amounting to ∼100 generations. The starting richness of metabolic guilds had a repeatable effect on bacterial community compositions, metabolic profiles, and acidity. The influence of a single metabolic guild, yeast in our study, played a dramatic role on function, but interestingly not on long-term species sorting trajectories of the remaining bacterial community. Our results together suggest an unexpected niche division between yeast and bacterial communities and evidence ecological selection on the microbial communities in our system.


Asunto(s)
Alimentos Fermentados , Microbiota , Saccharomyces cerevisiae , Bacterias/genética
20.
Fam Community Health ; 46(Suppl 1): S52-S65, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37696016

RESUMEN

Most incarcerated fathers have connections to their families, and the quality of their family relationships is important not only to their reentry success but also to shaping positive child and family outcomes. However, there is a lack of rigorous evidence about interventions designed to strengthen parent-child and other family relationships among formerly incarcerated parents. The purpose of this study was to develop and assess for feasibility and acceptability an intervention for formerly incarcerated fathers, co-parents, and their children. We created and implemented the Pathways for Parents after Incarceration Program (P4P), a multilevel intervention that focuses on strengthening positive parenting skills, building constructive co-parenting strategies, providing social support, and connecting families to needed specialized services. We delivered P4P virtually to 3 groups of participants, collecting data at several points. Results suggest that while the program was well liked and appreciated by participants and parent coaches and had a positive effect on parenting skills and attitudes, recruitment and retention were challenging. Findings suggest that P4P has the potential to support child and family well-being when fathers reenter by bolstering protective factors, and supporting access to necessary supports associated with improved reentry outcomes. Additional research is needed to address feasibility concerns and establish program efficacy.


Asunto(s)
Responsabilidad Parental , Padres , Humanos , Niño , Estudios de Factibilidad , Crianza del Niño
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