Carbohydrate Substrates Research Articles

Photocatalyst-free light-promoted carbohydrate synthesis and modification

Photoredox catalysis has recently emerged as a powerful approach for preparing oligosaccharides because it uses mild conditions, is compatible with partially or completely unprotected carbohydrate substrates, and exhibits impressive regio‐ and stereo‐selectivity and high functional group tolerance. However, most catalytic photoredox reactions require an external photocatalyst (organic dye or expensive transition-metal complex) to deliver key glycosyl radicals. Several photocatalyst-free photocatalytic reactions that avoid the use of expensive metal salts or organic-dye additives have received significant attention. In this review, we highlight the most recent developments in photocatalyst-free light-promoted carbohydrate synthesis and modification, which is expected to inspire broad interest in further innovations in the green synthesis of saccharides.

DACRA induces profound weight loss, satiety control, and increased mitochondrial respiratory capacity in adipose tissue.

Dual amylin and calcitonin receptor agonists (DACRAs) are therapeutic candidates in the treatment of obesity with beneficial effects on weight loss superior to suppression of food intake. Hence, suggesting effects on energy expenditure by possibly targeting mitochondria in metabolically active tissue. Male rats with HFD-induced obesity received a DACRA, KBP-336, every third day for 8 weeks. Upon study end, mitochondrial respiratory capacity (MRC), - enzyme activity, - transcriptional factors, and -content were measured in perirenal (pAT) and inguinal adipose tissue. A pair-fed group was included to examine food intake-independent effects of KBP-336. A vehicle-corrected weight loss (23.4 ± 2.8%) was achieved with KBP-336, which was not observed to the same extent with the food-restricted weight loss (12.4 ± 2.8%) (P < 0.001). Maximal coupled respiration supported by carbohydrate and lipid-linked substrates was increased after KBP-336 treatment independent of food intake in pAT (P < 0.01). Moreover, oligomycin-induced leak respiration and the activity of citrate synthase and β-hydroxyacetyl-CoA-dehydrogenase were increased with KBP-336 treatment (P < 0.05). These effects occurred without changes in mitochondrial content in pAT. These findings demonstrate favorable effects of KBP-336 on MRC in adipose tissue, indicating an increased energy expenditure and capacity to utilize fatty acids. Thus, providing more mechanistic insight into the DACRA-induced weight loss.

The mitochondrial physiology of torpor in ruby-throated hummingbirds, Archilochus colubris.

Hummingbirds save energy by facultatively entering torpor, but the physiological mechanisms underlying this metabolic suppression are largely unknown. We compared whole-animal and pectoralis mitochondrial metabolism between torpid and normothermic ruby-throated hummingbirds (Archilochus colubris). When fasting, hummingbirds were exposed to 10℃ ambient temperature at night, they entered torpor; average body temperature decreased by nearly 25℃ (From ∼37 to ∼13℃), and whole-animal metabolic rate (VO2) decreased by 95% compared to normothermia, a much greater metabolic suppression compared with mammalian daily heterotherms. We then measured pectoralis mitochondrial oxidative phosphorylation (OXPHOS) fueled by either carbohydrate or fatty acid substrates at both 39℃ and 10℃ in torpid and normothermic hummingbirds. Aside from a 20% decrease in electron transport system complex I-supported respiration with pyruvate, the capacity for OXPHOS at a common in vivo temperature did not differ in isolated mitochondria between torpor and normothermia. Similarly, the activities of pectoralis pyruvate dehydrogenase and 3-hydroxyacyl-CoA dehydrogenase did not differ between the states. Unlike heterothermic mammals, hummingbirds do not suppress muscle mitochondrial metabolism in torpor by active, temperature-independent mechanisms. Other mechanisms that may underly this impressive whole-animal metabolic suppression include decreasing ATP demand or relying on rapid passive cooling facilitated by the very small body size of A. colubris.

Hyperpolarized 13C NMR Reveals Pathway Regulation in Lactococcus lactis and Metabolic Similarities and Differences Across the Tree of Life.

The control of metabolic networks is incompletely understood, even for glycolysis in highly studied model organisms. Direct real-time observations of metabolic pathways can be achieved in cellular systems with 13C NMR using dissolution Dynamic Nuclear Polarization (dDNP NMR). The method relies on a short-lived boost of NMR sensitivity using a redistribution of nuclear spin states to increase the alignment of the magnetic moments by more than four orders of magnitude. This temporary boost in sensitivity allows detection of metabolism with sub-second time resolution. Here, we hypothesized that dDNP NMR would be able to investigate molecular phenotypes that are not easily accessible with more conventional methods. The use of dDNP NMR allows real-time insight into carbohydrate metabolism in a Gram-positive bacterium (Lactoccocus lactis), and comparison to other bacterial, yeast and mammalian cells shows differences in the kinetic barriers of glycolysis across the kingdoms of life. Nevertheless, the accumulation of non-toxic precursors for biomass at kinetic barriers is found to be shared across the kingdoms of life. We further find that the visualization of glycolysis using dDNP NMR reveals kinetic characteristics in transgenic strains that are not evident when monitoring the overall glycolytic rate only. Finally, dDNP NMR reveals that resting Lactococcus lactis cells use the influx of carbohydrate substrate to produce acetoin rather than lactate during the start of glycolysis. This metabolic regime can be emulated using suitably designed substrate mixtures to enhance the formation of the C4 product acetoin more than 400-fold. Overall, we find that dDNP NMR provides analytical capabilities that may help to clarify the intertwined mechanistic determinants of metabolism and the optimal usage of biotechnologically important bacteria.

Proton Pump Inhibitors. Investigating Their Role in Small Intestinal Bacterial Overgrowth

Proton pump inhibitors (PPIs) are widely used medications known for their effectiveness in reducing gastric acid production and their overall safety profile. Despite being valued for these properties, concerns have been raised regarding potential adverse effects associated with their long-term use. Various studies indicate a higher prevalence of small intestinal bacterial overgrowth (SIBO) in patients on prolonged PPI therapy, with symptoms ranging from bloating and diarrhea to malabsorption and nutrient deficiencies. Diagnosing SIBO primarily involves non-invasive breath tests that measure hydrogen and methane levels produced by bacterial fermentation after ingesting a carbohydrate substrate, such as lactulose or glucose. Direct aspiration and culture of small intestinal fluid offer a more definitive diagnosis but are invasive and less commonly performed. Treatment of SIBO focuses on reducing bacterial overgrowth by using antibiotics.This review aims to inform clinicians about the possible risks of PPI therapy and the importance of suspecting SIBO in patients with nonspecific gastrointestinal symptoms.

Sandwich-Like Complexation of Carbohydrates by Hydrogen Bonding and CH-π Interactions

Introduction: The design of carbohydrate-binding agents (artificial carbohydrate receptors) that enable selective and effective biomimetic recognition via noncovalent interactions is aimed either at a better understanding of natural recognition phenomena or at various potential applications in medicine and other fields. Although very interesting artificial receptors have been developed, the exact prediction of the receptor selectivity remains a challenge. Results and Methods: A molecular architecture based on a 1,3,5-substituted 2,4,6-triethylbenzene backbone bearing two aminopyridine- or aminopyrimidine-based recognition units and a purine moiety, which acts as both a hydrogen bonding site and a bridging component for the incorporation of additional substituents, has proved to be very useful for the development of effective carbohydrate-binding agents. This type of compounds has the ability to bind suitable carbohydrates through combined noncovalent interactions, where CH···π interactions can be formed on both faces of the carbohydrate substrate. The successful syntheses of the target compounds can be realized by the use of microwave irradiation and sealed tubes. The performed binding studies included 1H NMR spectroscopic titrations and measurements by isothermal titration calorimetry. Conclusion: The new compounds were developed as artificial receptors especially for carbohydrates with an all-equatorial substitution pattern and have the ability to predictably form strong 1:1 complexes with a suitable substrate. The use of the purine moiety in the construction of carbohydrate receptors with a 1,3,5-substituted 2,4,6-triethylbenzene backbone has proved to be a very promising approach. The possibilities for structural variation of this molecular architecture are manifold. As a result, a wide range of compounds can be synthesized to perform extensive studies on the relationships between structure and binding efficiency. Graphical Abstract Short Text: New compounds were developed as artificial receptors especially for carbohydrates with an all-equatorial substitution pattern and have the ability to predictably form 1:1 complexes with a suitable substrate. Key Topics: Artificial carbohydrate receptors; Combination of hydrogen bonding and CH۔۔۔π interactions; Molecular recognition

Integrative genomic reconstruction of carbohydrate utilization networks in bifidobacteria: global trends, local variability, and dietary adaptation.

Bifidobacteria are among the earliest colonizers of the human gut, conferring numerous health benefits. While multiple Bifidobacterium strains are used as probiotics, accumulating evidence suggests that the individual responses to probiotic supplementation may vary, likely due to a variety of factors, including strain type(s), gut community composition, dietary habits of the consumer, and other health/lifestyle conditions. Given the saccharolytic nature of bifidobacteria, the carbohydrate composition of the diet is one of the primary factors dictating the colonization efficiency of Bifidobacterium strains. Therefore, a comprehensive understanding of bifidobacterial glycan metabolism at the strain level is necessary to rationally design probiotic or synbiotic formulations that combine bacterial strains with glycans that match their nutrient preferences. In this study, we systematically reconstructed 66 pathways involved in the utilization of mono-, di-, oligo-, and polysaccharides by analyzing the representation of 565 curated metabolic functional roles (catabolic enzymes, transporters, transcriptional regulators) in 2973 non-redundant cultured Bifidobacterium isolates and metagenome-assembled genomes (MAGs). Our analysis uncovered substantial heterogeneity in the predicted glycan utilization capabilities at the species and strain level and revealed the presence of a yet undescribed phenotypically distinct subspecies-level clade within the Bifidobacterium longum species. We also identified Bangladeshi isolates harboring unique gene clusters tentatively implicated in the breakdown of xyloglucan and human milk oligosaccharides. Predicted carbohydrate utilization phenotypes were experimentally characterized and validated. Our large-scale genomic analysis considerably expands the knowledge of carbohydrate metabolism in bifidobacteria and provides a foundation for rationally designing single- or multi-strain probiotic formulations of a given bifidobacterial species as well as synbiotic combinations of bifidobacterial strains matched with their preferred carbohydrate substrates.

Mild and General Protocol for Selective Deacetylation of Acetyl/Benzoyl-Protected Carbohydrates.

Herein, we report a mild and general protocol for chemoselective deacetylation of mixed acetyl- and benzoyl-protected carbohydrates under mild acidic conditions. The protocol allows quick access to partially protected carbohydrates, which serve as versatile synthetic intermediates during the total synthesis of various mono- and oligosaccharide targets. The applicability of the developed protocol was successfully demonstrated on a range of carbohydrate substrates of various configurations and substitution patterns featuring functionalized aliphatic and aromatic aglycones. The protocol has shown excellent compatibility with the widely used O-anomeric protecting groups, prespacer aglycones, and thioglycoside glycosyl donors.

Mitochondrial respiration is lower in the intrauterine growth-restricted fetal sheep heart.

Fetuses affected by intrauterine growth restriction have an increased risk of developing heart disease and failure in adulthood. Compared with controls, late gestation intrauterine growth-restricted (IUGR) fetal sheep have fewer binucleated cardiomyocytes, reflecting a more immature heart, which may reduce mitochondrial capacity to oxidize substrates. We hypothesized that the late gestation IUGR fetal heart has a lower capacity for mitochondrial oxidative phosphorylation. Left (LV) and right (RV) ventricles from IUGR and control (CON) fetal sheep at 90% gestation were harvested. Mitochondrial respiration (states 1-3, LeakOmy, and maximal respiration) in response to carbohydrates and lipids, citrate synthase (CS) activity, protein expression levels of mitochondrial oxidative phosphorylation complexes (CI-CV), and mRNA expression levels of mitochondrial biosynthesis regulators were measured. The carbohydrate and lipid state 3 respiration rates were lower in IUGR than CON, and CS activity was lower in IUGR LV than CON LV. However, relative CII and CV protein levels were higher in IUGR than CON; CV expression level was higher in IUGR than CON. Genes involved in lipid metabolism had lower expression in IUGR than CON. In addition, the LV and RV demonstrated distinct differences in oxygen flux and gene expression levels, which were independent from CON and IUGR status. Low mitochondrial respiration and CS activity in the IUGR heart compared with CON are consistent with delayed cardiomyocyte maturation, and CII and CV protein expression levels may be upregulated to support ATP production. These insights will provide a better understanding of fetal heart development in an adverse in utero environment. KEY POINTS: Growth-restricted fetuses have a higher risk of developing and dying from cardiovascular diseases in adulthood. Mitochondria are the main supplier of energy for the heart. As the heart matures, the substrate preference of the mitochondria switches from carbohydrates to lipids. We used a sheep model of intrauterine growth restriction to study the capacity of the mitochondria in the heart to produce energy using either carbohydrate or lipid substrates by measuring how much oxygen was consumed. Our data show that the mitochondria respiration levels in the growth-restricted fetal heart were lower than in the normally growing fetuses, and the expression levels of genes involved in lipid metabolism were also lower. Differences between the right and left ventricles that are independent of the fetal growth restriction condition were identified. These results indicate an impaired metabolic maturation of the growth-restricted fetal heart associated with a decreased capacity to oxidize lipids postnatally.

The role of food preservatives in shaping metabolic profile and chemical sensitivity of fungi - an extensive study on crucial mycological food contaminants from the genus Neosartorya (Aspergillus spp.)

Food preservatives are crucial in fruit production, but fungal resistance is a challenge. The main objective was to compare the sensitivity of Neosartorya spp. isolates to preservatives used in food security applications and to assess the role of metabolic properties in shaping Neosartorya spp. resistance. Sodium metabisulfite, potassium sorbate, sodium bisulfite and sorbic acid showed inhibitory effects, with sodium metabisulfite the most effective. Tested metabolic profiles included fungal growth intensity and utilization of amines and amides, amino acids, polymers, carbohydrates and carboxylic acids. Significant decreases in the utilization of all tested organic compound guilds were observed after fungal exposure to food preservatives compared to the control. Although the current investigation was limited in the number of predominately carbohydrate substrates and the breadth of metabolic responses, extensive sensitivity panels are logical step in establishing a course of action against spoilage agents in food production being important approach for innovative food chemistry.

Integrating multi-platform assembly to recover MAGs from hot spring biofilms: insights into microbial diversity, biofilm formation, and carbohydrate degradation

BackgroundHot spring biofilms provide a window into the survival strategies of microbial communities in extreme environments and offer potential for biotechnological applications. This study focused on green and brown biofilms thriving on submerged plant litter within the Sungai Klah hot spring in Malaysia, characterised by temperatures of 58–74 °C. Using Illumina shotgun metagenomics and Nanopore ligation sequencing, we investigated the microbial diversity and functional potential of metagenome-assembled genomes (MAGs) with specific focus on biofilm formation, heat stress response, and carbohydrate catabolism.ResultsLeveraging the power of both Illumina short-reads and Nanopore long-reads, we employed an Illumina-Nanopore hybrid assembly approach to construct MAGs with enhanced quality. The dereplication process, facilitated by the dRep tool, validated the efficiency of the hybrid assembly, yielding MAGs that reflected the intricate microbial diversity of these extreme ecosystems. The comprehensive analysis of these MAGs uncovered intriguing insights into the survival strategies of thermophilic taxa in the hot spring biofilms. Moreover, we examined the plant litter degradation potential within the biofilms, shedding light on the participation of diverse microbial taxa in the breakdown of starch, cellulose, and hemicellulose. We highlight that Chloroflexota and Armatimonadota MAGs exhibited a wide array of glycosyl hydrolases targeting various carbohydrate substrates, underscoring their metabolic versatility in utilisation of carbohydrates at elevated temperatures.ConclusionsThis study advances understanding of microbial ecology on plant litter under elevated temperature by revealing the functional adaptation of MAGs from hot spring biofilms. In addition, our findings highlight potential for biotechnology application through identification of thermophilic lignocellulose-degrading enzymes. By demonstrating the efficiency of hybrid assembly utilising Illumina-Nanopore reads, we highlight the value of combining multiple sequencing methods for a more thorough exploration of complex microbial communities.

Comparative Genome Analysis and Characterization of the Probiotic Properties of Lactic Acid Bacteria Isolated from the Gastrointestinal Tract of Wild Boars in the Czech Republic.

Probiotics are crucial components for maintaining a healthy gut microbiota in pigs, especially during the weaning period. Lactic acid bacteria (LAB) derived from the gastrointestinal tract of wild boars can serve as an abundant source of beneficial probiotic strains with suitable properties for use in pig husbandry. In this study, we analyzed and characterized 15strains of Limosilactobacillusmucosae obtained from the gut contents of wild boars to assess their safety and suitability as probiotic candidates. The strains were compared using pan-genomic analysis with 49 L.mucosae strains obtained from the NCBI database. All isolated strains demonstrated their safety by showing an absence of transferrable antimicrobial resistance genes and hemolysin activity. Based on the presence of beneficial genes, five candidates with probiotic properties were selected and subjected to phenotypic profiling. These five selected isolates exhibited the ability to survive conditions mimicking passage through the host's digestive tract, such as low pH and the presence of bile salts. Furthermore, five selected strains demonstrated the presence of corresponding carbohydrate-active enzymes and the ability to utilize various carbohydrate substrates. These strains can enhance the digestibility of oligosaccharide or polysaccharide substrates found in food or feed, specifically resistant starch, α-galactosides, cellobiose, gentiobiose, and arabinoxylans. Based on the results obtained, the L.mucosae isolates tested in this study appear to be promising candidates for use as probiotics in pigs.

Bacterial diversity and community level physiological profiling of terasi (Indonesian shrimp paste) to ensure its food safety

Fermentation is a technology to increase the economic value and preserve of seasonal products such as tiny shrimps. This study aimed to ensure the safety and the length of production time of shrimp paste by determining the bacteria involved, during the shrimp paste fermentation process with 10% and 15% salt content. Identification of halophilic bacteria by 16S rRNA used primers 27F and 1492R. Identification of unculturable bacteria used bacterial amplification in the V3-V4 rRNA region. Bacterial activity was observed using the Community Level Physiology Profiling technique. The results showed that the dominant bacteria in shrimp paste with 10% and 15% salt were culturable, i.e., Staphylococcus nepalensis, Salinicoccus qingdaoensis, and Staphylococcus cochnii. In the unculturable identification, the dominant bacteria in shrimp paste with 10% salt were Alkalibacillus, Alkalibacterium, Tetragenococcus, whereas the shrimp paste with 15% salt was dominated by genus of Salimicrobium, Staphylococcus, Corticicoccus, Alkalibacterium and Lentibacillus. The shrimp paste with 10% salt used a high amount of carbohydrate and carboxylic acid substrate. Both 10% and 15% salt of terasi were safe to consume due to no pathogenic bacteria contained. The production of shrimp paste with 10% salt is more profitable due to the low production cost and faster production time.

Application of Acetate as a Substrate for the Production of Value-Added Chemicals in Escherichia coli.

At present, the production of the majority of valuable chemicals is dependent on the microbial fermentation of carbohydrate substrates. However, direct competition is a potential problem for microbial feedstocks that are also used within the food/feed industries. The use of alternative carbon sources, such as acetate, has therefore become a research focus. As a common organic acid, acetate can be generated from lignocellulosic biomass and C1 gases, as well as being a major byproduct in microbial fermentation, especially in the presence of an excess carbon source. As a model microorganism, Escherichia coli has been widely applied in the production of valuable chemicals using different carbon sources. Recently, several valuable chemicals (e.g., succinic acid, itaconic acid, isobutanol, and mevalonic acid) have been investigated for synthesis in E. coli using acetate as the sole carbon source. In this review, we summarize the acetate metabolic pathway in E. coli and recent research into the microbial production of chemical compounds in E. coli using acetate as the carbon source. Although microbial synthetic pathways for different compounds have been developed in E. coli, the production titer and yield are insufficient for commercial applications. Finally, we discuss the development prospects and challenges of using acetate for microbial fermentation.

Metagenomics reveals microbial communities and functional differences during chili pepper (Capsicum frutescens L.) natural fermentation: Effects of brines and containers

AbstractThe study aimed to investigate the effect of fermentation brines and containers on the composition and functional dissimilarity of microbiota in fermented chili peppers: pool with fresh brine (PFB), pool with aged brine (PAB), jar with FB, and jar with AB. The results showed that brines had a greater impact on microbial diversity and fungal community structure than containers, whereas containers had a greater impact on bacterial community structure than brines. At the end of chili pepper fermentation, the dominant bacteria were unclassified_g__Pseudomonas, Lactobacillus_alimentarius, and Halococcus_thailandensis, whereas the dominant fungi were Pichia_membranifaciens and Wallemia_ichthyophaga. Based on the metagenomics functional analysis, the dominant bacteria and fungi were highly related to amino acid metabolism, glycerophospholipid metabolism, and most enzymes that promote carbohydrate substrate modulation. The fermented brines had a larger impact than containers on microbial function. Specifically, the use of FB was found to be beneficial for the biosynthesis of tetracycline, carotenoid, and isoflavonoid. On the other hand, AB was found to be beneficial for the biosynthesis of unsaturated fatty acids, amino acids, and various types of N‐glycan.

Predicted metabolic roles and stress responses provide insights into candidate phyla Hydrogenedentota and Sumerlaeota as members of the rare biosphere in biofilms from various environments.

Pustular mats from Shark Bay, Western Australia, host complex microbial communities bound within an organic matrix. These mats harbour many poorly characterized organisms with low relative abundances (<1%), such as candidate phyla Hydrogenedentota and Sumerlaeota. Here, we aim to constrain the metabolism and physiology of these candidate phyla by analyzing two representative metagenome-assembled genomes (MAGs) from a pustular mat. Metabolic reconstructions of these MAGs suggest facultatively anaerobic, chemoorganotrophic lifestyles of both organisms and predict that both MAGs can metabolize a diversity of carbohydrate substrates. Ca. Sumerlaeota possesses genes involved in degrading chitin, cellulose and other polysaccharides, while Ca. Hydrogenedentota can metabolize cellulose derivatives in addition to glycerol, fatty acids and phosphonates. Both Ca. phyla can respond to nitrosative stress and participate in nitrogen metabolism. Metabolic comparisons of MAGs from Shark Bay and those from various polyextreme environments (i.e., hot springs, hydrothermal vents, subsurface waters, anaerobic digesters, etc.) reveal similar metabolic capabilities and adaptations to hypersalinity, oxidative stress, antibiotics, UV radiation, nitrosative stress, heavy metal toxicity and life in surface-attached communities. These adaptations and capabilities may account for the widespread nature of these organisms and their contributions to biofilm communities in a range of extreme surface and subsurface environments.

Characterization of dual-species biofilms formed by bacteria isolated from milk

This study evaluated biofilm formation of bacteria isolated from raw milk and investigated the composition of extracellular polymeric substances (EPS) using Raman spectroscopy. Biofilms were formed from six isolates on a 96-well microplate at 7 and 25 °C in 1 and 10% reconstituted whole milk. Biofilms were then formed on stainless steel coupons at 7 °C from two isolates identified as strong biofilm producers. Pseudomonas fluorescens, a frequent contaminant of raw milk, forms single or dual-species biofilms with Staphylococcus aureus; however, the sessile cell number of S. aureus remained constant over ten days. Raman spectroscopy identified that EPS composition varied with carbohydrate and protein substrates, the predominant components in P. fluorescens single or dual-species biofilms. Understanding the formation and composition of biofilms at different temperatures and in milk concentrations that simulate the equipment used in the dairy industry is a significant subsidy for establishing adequate sanitary protocols for their mitigation.

Screening of novel carbohydrate-derived thioureas for antibacterial activity

Compounds synthesized from carbohydrate substrates have yielded promising lead molecules for pharmaceutical developments, as many are approved for the clinical management of a wide range of diseases. Among them, thiourea moieties are the gold mines of antibacterial molecules. In view of the lack and need for new antibiotics, a series of 16 D-fructose-based thiourea compounds were synthesized from asymmetric aldol reaction and isopropylidenation. The new compounds were established from nuclear magnetic resonance, Fourier-transform infrared, and electrospray ionization mass spectrometry. Using disk diffusion assay for antibiotic susceptibility, four of the novel compounds were found to have concentration-dependent antibacterial activities. The addition of trifluoromethyl groups at the meta-position on the phenyl ring of the thioureas appeared to promote bacterial inhibitory action. Thiourea 2a exhibited the most potent activity against the Gram-negative species, Klebsiella pneumoniae, Escherichia coli, and Salmonella typhi, as well as the Gram-positive species, Micrococcus luteus; but not against all bacteria tested. Thiourea 2b and 3a had lower efficacy but showed better broad-spectrum activity against most bacteria tested. Thiourea 3b displayed species-specific activity only against K. pneumoniae and S. typhi. Our findings show the benefits and prospects of synthesizing new carbohydrate compounds for therapeutic medication.

Evaluation of the properties of dry bacterial cellulose synthesized from coffee kombucha fermentation dried with different drying methods

The fermentation of coffee kombucha (CK) utilizes carbohydrate substrates to produce bacterial cellulose (BC), a naturally occurring material synthesized by some bacteria including Gluconacetobacter spp. BC can be used to develop materials for biomedical and food industry applications including biomaterial and biodegradable packaging materials, medical devices, biosensors, or drug delivery systems. BC contains approximately 97% water, which is not convenient and portable for many applications. Drying increases the stability of BC and may influence the properties of BC. The effect of drying methods on the BC properties can determine the suitability of the material for various applications. The objectives of this study were to use four drying methods to synthesize BCs from the fermentation of CK and evaluate their physicochemical, mechanical, and morphological properties. The drying methods included: oven-drying (OD), freeze-drying, vacuum-oven-drying, and Büchner funnel vacuum-drying (BFVD). FTIR analyses confirmed the structure of cellulose for all methods. OD-BCs had the highest tensile stress at break with 24.67 ± 4.40 (MPa). SEM images showed randomly structured fibers with diameters ranging from 61.58 to 72.18 nm. XRD analysis revealed that OD had the highest degree of crystallinity with 78.67%. All BCs decomposed between 230 and 400 °C. This study demonstrated that using different drying methods could alter the structural properties of BCs potentially providing distinctive applications in various industries.

Equine maternal aging affects the metabolomic profile of oocytes and follicular cells during different maturation time points.

Introduction: Oocyte quality and fertility decline with advanced maternal age. During maturation within the ovarian follicle, the oocyte relies on the associated somatic cells, specifically cumulus and granulosa cells, to acquire essential components for developmental capacity. Methods: A nontargeted metabolomics approach was used to investigate the effects of mare age on different cell types within the dominant, follicular-phase follicle at three time points during maturation. Metabolomic analyses from single oocytes and associated cumulus and granulosa cells allowed correlations of metabolite abundance among cell types. Results and Discussion: Overall, many of the age-related changes in metabolite abundance point to Impaired mitochondrial metabolic function and oxidative stress in oocytes and follicular cells. Supporting findings include a higher abundance of glutamic acid and triglycerides and lower abundance of ceramides in oocytes and somatic follicular cells from old than young mares. Lower abundance of alanine in all follicular cell types from old mares, suggests limited anaerobic energy metabolism. The results also indicate impaired transfer of carbohydrate and free fatty acid substrates from cumulus cells to the oocytes of old mares, potentially related to disruption of transzonal projections between the cell types. The identification of age-associated alterations in the abundance of specific metabolites and their correlations among cells contribute to our understanding of follicular dysfunction with maternal aging.