RESUMO
OBJECTIVES: The aim of the present study was to examine donkey sperm quality after intratesticular injection of hypertonic mannitol (HM) and saline (HS). METHODS: Randomly assigned to five treatment groups were 15 adult male donkeys: (1) Control group (no treatment), (2) Surgery group (surgical castration for testosterone control), (3) NS group (normal saline intratesticular injection), (4) HS group (hypertonic saline), and (5) HM group. We injected 20 mL per testicle. We took 5 mL blood from all donkeys before injection. Castration was performed under general anesthesia 60 days later. Samples included blood and testicular tissue. Total motility (TM), progressive motility (PM), movementy features, DNA damage, morphology, viability, and plasma membrane functionality were evaluated. Hormone analyses, histomorphometric studies and oxidative stress indices including total antioxidant capacity (TAC), glutathione peroxidase (GPx), glutathione (GSH), superoxide dismutase (SOD), malondialdehyde (MDA), and NADP+/NADPH were evaluated. Apoptosis, pyroptosis-related Bax, Caspase-1, GSDMD, and Bcl-2 expression were also assessed. RESULTS: In HS and HM groups, testosterone, epididymal sperm count, motility, viability, and plasma membrane functionality dropped while sperm DNA damage increased. HS and HM groups had significantly lower histomorphometric parameters, TAC, GPx, SOD, GSH, and Bcl-2 gene expression. MDA, NADP+/NADPH, Bax, Caspase-1, and GSDMD gene expression were substantially higher in the HS and HM groups than in the control group. CONCLUSIONS: Toxic effects of hypertonic saline and mannitol on reproductive parameters were seen following, hence, they might be considered as a good chemical sterilizing treatment in donkeys.
Assuntos
Manitol , Solução Salina , Animais , Masculino , Antioxidantes/metabolismo , Proteína X Associada a bcl-2 , Caspases/metabolismo , Manitol/farmacologia , Manitol/metabolismo , NADP/metabolismo , Estresse Oxidativo , Solução Salina/metabolismo , Solução Salina/farmacologia , Sêmen , Espermatozoides , Superóxido Dismutase/metabolismo , Testículo/metabolismo , TestosteronaRESUMO
Biochemistry of carbon assimilation in aerobic methylotrophs growing on reduced C1 compounds has been intensively studied due to the vital role of these microorganisms in nature. The biochemical pathways of carbon assimilation in methylotrophs growing on multi-carbon substrates are insufficiently explored. Here we elucidated the metabolic route of mannitol assimilation in the alphaproteobacterial facultative methylotroph Methylobrevis pamukkalensis PK2. Two key enzymes of mannitol metabolism, mannitol-2-dehydrogenase (MTD) and fructokinase (FruK), were obtained as His-tagged proteins by cloning and expression of mtd and fruK genes in Escherichia coli and characterized. Genomic analysis revealed that further transformation of fructose-6-phosphate proceeds via the Entner-Doudoroff pathway. During growth on mannitol + methanol mixture, the strain PK2 consumed both substrates simultaneously demonstrating independence of C1 and C6 metabolic pathways. Genome screening showed that genes for mannitol utilization enzymes are present in other alphaproteobacterial methylotrophs predominantly capable of living in association with plants. The capability to utilize a variety of carbohydrates (sorbitol, glucose, fructose, arabinose and xylose) suggests a broad adaptability of the strain PK2 to live in environments where availability of carbon substrate dynamically changes.
Assuntos
Frutoquinases , Manitol , Manitol/metabolismo , Frutoquinases/metabolismo , Frutoquinases/genética , Manitol Desidrogenases/metabolismo , Manitol Desidrogenases/genética , Frutosefosfatos/metabolismo , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Redes e Vias Metabólicas/genética , Metanol/metabolismo , Escherichia coli/genética , Escherichia coli/metabolismo , Escherichia coli/crescimento & desenvolvimentoRESUMO
Six lactic acid bacteria (LAB) isolated from Algerian sheep's milk, traditional butter, date palm sap and barley, which produce dextran, mannitol, oligosaccharides and vitamin B2 have been characterized. They were identified as Leuconostoc mesenteroides (A4X, Z36P, B12 and O9) and Liquorilactobacillus mali (BR201 and FR123). Their exopolysaccharides synthesized from sucrose by dextransucrase (Dsr) were characterized as dextrans with (1,6)-D-glucopyranose units in the main backbone and branched at positions O-4, O-2 and/or O-3, with D-glucopyranose units in the side chain. A4X was the best dextran producer (4.5 g/L), while the other strains synthesized 2.1-2.7 g/L. Zymograms revealed that L. mali strains have a single Dsr with a molecular weight (Mw) of ~ 145 kDa, while the Lc. mesenteroides possess one or two enzymes with 170-211 kDa Mw. As far as we know, this is the first detection of L. mali Dsr. Analysis of metabolic fluxes from sucrose revealed that the six LAB produced mannitol (~ 12 g/L). The co-addition of maltose-sucrose resulted in the production of panose (up to 37.53 mM), an oligosaccharide known for its prebiotic effect. A4X, Z36P and B12 showed dextranase hydrolytic enzymatic activity and were able to produce another trisaccharide, maltotriose, which is the first instance of a dextranase activity encoded by Lc. mesenteroides strains. Furthermore, B12 and O9 grew in the absence of riboflavin (vitamin B2) and synthesized this vitamin, in a defined medium at the level of ~ 220 µg/L. Therefore, these LAB, especially Lc. mesenteroides B12, are good candidates for the development of new fermented food biofortified with functional compounds.
Assuntos
Leuconostoc mesenteroides , Animais , Ovinos , Dextranos/metabolismo , Dextranase/química , Dextranase/metabolismo , Manitol/metabolismo , Mali , Glucosiltransferases/metabolismo , Oligossacarídeos/química , Sacarose/metabolismo , Vitaminas/metabolismo , Leuconostoc/metabolismoRESUMO
BACKGROUND: Transforming waste and nonfood materials into bulk biofuels and chemicals represents a major stride in creating a sustainable bioindustry to optimize the use of resources while reducing environmental footprint. However, despite these advancements, the production of high-value natural products often continues to depend on the use of first-generation substrates, underscoring the intricate processes and specific requirements of their biosyntheses. This is also true for Streptomyces lividans, a renowned host organism celebrated for its capacity to produce a wide array of natural products, which is attributed to its genetic versatility and potent secondary metabolic activity. Given this context, it becomes imperative to assess and optimize this microorganism for the synthesis of natural products specifically from waste and nonfood substrates. RESULTS: We metabolically engineered S. lividans to heterologously produce the ribosomally synthesized and posttranslationally modified peptide bottromycin, as well as the polyketide pamamycin. The modified strains successfully produced these compounds using waste and nonfood model substrates such as protocatechuate (derived from lignin), 4-hydroxybenzoate (sourced from plastic waste), and mannitol (from seaweed). Comprehensive transcriptomic and metabolomic analyses offered insights into how these substrates influenced the cellular metabolism of S. lividans. In terms of production efficiency, S. lividans showed remarkable tolerance, especially in a fed-batch process using a mineral medium containing the toxic aromatic 4-hydroxybenzoate, which led to enhanced and highly selective bottromycin production. Additionally, the strain generated a unique spectrum of pamamycins when cultured in mannitol-rich seaweed extract with no additional nutrients. CONCLUSION: Our study showcases the successful production of high-value natural products based on the use of varied waste and nonfood raw materials, circumventing the reliance on costly, food-competing resources. S. lividans exhibited remarkable adaptability and resilience when grown on these diverse substrates. When cultured on aromatic compounds, it displayed a distinct array of intracellular CoA esters, presenting promising avenues for polyketide production. Future research could be focused on enhancing S. lividans substrate utilization pathways to process the intricate mixtures commonly found in waste and nonfood sources more efficiently.
Assuntos
Produtos Biológicos , Policetídeos , Streptomyces lividans/genética , Streptomyces lividans/metabolismo , Lignina/metabolismo , Produtos Biológicos/metabolismo , Policetídeos/metabolismo , Manitol/metabolismoRESUMO
Brown macroalgae is a promising feedstock for biorefinery owing to its high biomass productivity and contents of carbohydrates such as alginate and mannitol. However, the limited availability of microbial platforms efficiently catabolizing the brown macroalgae sugars has restricted its utilization. In this study, the direct production of citramalate, an important industrial compound, was demonstrated from brown macroalgae by utilizing Vibrio sp. dhg, which has a remarkably efficient catabolism of alginate and mannitol. Specifically, citramalate synthase from Methanocaldococcus jannaschii was synthetically expressed, and competing pathways were removed to maximally redirect the carbon flux toward citramalate production. Notably, a resulting strain, VXHC, produced citramalate up to 9.8 g/L from a 20 g/L mixture of alginate and mannitol regardless of their ratios. Citramalate was robustly produced even when diverse brown macroalgae were provided directly. Collectively, this study showcased the high potential of brown macroalgae biorefinery using Vibrio sp. dhg.
Assuntos
Malatos , Alga Marinha , Vibrio , Alga Marinha/metabolismo , Manitol/metabolismo , Vibrio/metabolismo , Alginatos/metabolismoRESUMO
D-mannitol is a six-carbon sugar alcohol and one of the most abundant polyols in the nature. With antioxidant and osmotic pressure-regulating effects and non-metabolism by the human body, D-mannitol has been widely used in functional food and pharmaceutical industries. At present, a major way for industrial production of D-mannitol is chemical hydrogenation. In addition, D-Mannitol can be produced by microbial metabolism or catalysis. Compared with the chemical hydrogenation, the microbial methods for synthesizing mannitol do not produce sorbitol as a by-product and have the advantages of mild reaction conditions, strong specificity, and high conversion rate. Microbial fermentation is praised for easy access of strains and raw materials and simple separation of the product. Microbial catalysis usually adopts a multi-enzyme coupling strategy, which uses enzymes produced by engineered bacteria for whole-cell catalysis, and the cofactor recycling pathway is introduced to replenish expensive cofactor. This method can achieve high yields with cheap substrates under mild conditions without the formation of by-products. However, the application of microbial methods in the industrial production of D-mannitol is limited by the high costs of fermentation media and substrates and the long reaction time. This article reviews the reported microbial methods for producing D-mannitol, including the use of high-yielding strains and their fermentation processes, the utilization of low-cost substrates, whole-cell catalytic strategies, and the process control for high productivity. The biosynthesis of mannitol is not only of great significance for promoting industrial upgrading and realizing green manufacturing, but also provides strong support for the development of new bio-based products to meet the growing market demand. With the continuous improvement of technological innovation and industrial chain, it is expected to become one of the main ways of mannitol production in the future.
Assuntos
Fermentação , Microbiologia Industrial , Manitol , Manitol/metabolismo , Microbiologia Industrial/métodos , Bactérias/metabolismo , Bactérias/genética , Engenharia Metabólica/métodosRESUMO
Riboflavin overproduction byCorynebacterium glutamicumwas achieved by screening synthetic operons, enabling fine-tuned expression of the riboflavin biosynthetic genesribGCAH.The synthetic operons were designed by means of predicted translational initiation rates of each open reading frame, with the best-performing selection enabling riboflavin overproduction without negatively affecting cell growth. Overexpression of the fructose-1,6-bisphosphatase (fbp) and 5-phosphoribosyl 1-pyrophosphate aminotransferase (purF) encoding genes was then done to redirect the metabolic flux towards the riboflavin precursors. The resulting strain produced 8.3 g l-1of riboflavin in glucose-based fed-batch fermentations, which is the highest reported riboflavin titer withC. glutamicum. Further genetic engineering enabled both xylose and mannitol utilization byC. glutamicum, and we demonstrated riboflavin overproduction with the xylose-rich feedstocks rice husk hydrolysate and spent sulfite liquor, and the mannitol-rich feedstock brown seaweed hydrolysate. Remarkably, rice husk hydrolysate provided 30% higher riboflavin yields compared to glucose in the bioreactors.
Assuntos
Corynebacterium glutamicum , Engenharia Metabólica , Riboflavina , Riboflavina/biossíntese , Riboflavina/química , Riboflavina/metabolismo , Corynebacterium glutamicum/metabolismo , Corynebacterium glutamicum/genética , Xilose/metabolismo , Fermentação , Glucose/metabolismo , Óperon , Manitol/metabolismo , Manitol/química , Reatores Biológicos , Engenharia GenéticaRESUMO
Abstract Various chemical compounds, including surfactants, when introduced to culture media may increase the permeability of cellular membranes and thereby affect the quantity of metabolites excreted by cells. The aim of the present study was to evaluate the impact of detergents including Triton X-100, Span 20 and Tween 80 on erythritol production from glycerol by Yarrowia lipolytica Wratislavia K1 in a shake-flask experiment, batch and fed-batch cultures. When Span 20 was added to a fed-batch culture with glycerol as a carbon source (300 g L-1), erythritol production increased by 15% compared to the culture without the surfactant where it reached 142 g L-1 after 5 days, which corresponded to 0.47 g g-1 yield and productivity of 1.1 g L-1 h-1. Therefore, it was concluded that Span 20 considerably enhanced the production of this polyol from glycerol.
Assuntos
Tensoativos/metabolismo , Meios de Cultura/metabolismo , Yarrowia/metabolismo , Eritritol/biossíntese , Manitol/metabolismo , Polissorbatos/análise , Polissorbatos/metabolismo , Tensoativos/análise , Octoxinol/análise , Octoxinol/metabolismo , Meios de Cultura/química , Eritritol/análise , Manitol/análiseRESUMO
The isolation of mannitol-negative methicillin-resistant Staphylococcus aureus from nasal swabs is reported. Among the 59 isolates, 9 (15%) isolates were mannitol-negative; all of these isolates were categorized as staphylococcal cassette chromosome mec (SCCmec) type IVa. This report emphasizes that mannitol fermentation on mannitol salt agar should not be used as the sole criterion when screening nasal swab specimens for S. aureus.
Assuntos
Humanos , Manitol/metabolismo , Staphylococcus aureus Resistente à Meticilina/isolamento & purificação , Staphylococcus aureus Resistente à Meticilina/metabolismo , Mucosa Nasal/microbiologia , Brasil , DNA Bacteriano/genética , Fermentação , Loci Gênicos , Staphylococcus aureus Resistente à Meticilina/classificaçãoRESUMO
This study was conducted to determine the species distribution, antimicrobial resistance pheno- and genotypes and virulence traits of mannitol-positive methicillin-resistant staphylococci (MRS) isolated from pigs in Nsukka agricultural zone, Nigeria. Twenty mannitol-positive methicillin-resistant coagulase-negative staphylococcal (MRCoNS) strains harboring the
Assuntos
Animais , Farmacorresistência Bacteriana Múltipla/genética , Fermentação/fisiologia , Manitol/metabolismo , Staphylococcus aureus Resistente à Meticilina/isolamento & purificação , Staphylococcus aureus Resistente à Meticilina/metabolismo , Staphylococcus haemolyticus/isolamento & purificação , Staphylococcus haemolyticus/metabolismo , Antibacterianos/farmacologia , Proteínas de Bactérias/genética , DNA Girase/genética , DNA Bacteriano/genética , Genes Bacterianos/genética , Testes de Sensibilidade Microbiana , Staphylococcus aureus Resistente à Meticilina/genética , Staphylococcus aureus Resistente à Meticilina/patogenicidade , Nigéria , Proteínas de Ligação às Penicilinas/genética , Infecções Estafilocócicas/microbiologia , Staphylococcus haemolyticus/genética , Staphylococcus haemolyticus/patogenicidade , Suínos/microbiologiaRESUMO
Paracoccidioides brasiliensis foi cultivado em meio de Fava Netto a 37-C. células na fase exponencial foram obtidas e homogeneizadas em tampäo fosfato 0,2M pH 7,2. Os experimentos de respirometria foram realizados a partir do extrato livre de células pelo método polarográfico. Entre os açúcares e alcoóis testados, manitol foi o substrato que exerceu maior estímulo sobre a respiraçäo endógena, enquanto glicose, xilose e trealose mostraram fraco efeito sobre a mesma. Glicerol, sacarose e maltose näo apresentaram nenhum efeito sobre a respiraçäo endógena. De todos os L aminoácidos testados glicina apresentou maior efeito estimulante sobre a respiraçäo endógena enquanto alanina mostrou o menor efeito. Entre os ácidos orgânicos, aspartato demonstrou o maior efeito estimulante sobre a respiraçäo endógena, enquanto oxalacetato e citrato exerceram fraco efeito sobre a mesma. Malato apresentou o menor efeito estimulante sobre a respiraçäo endógena