The Experts below are selected from a list of 91746 Experts worldwide ranked by ideXlab platform
Guangming Zeng - One of the best experts on this subject based on the ideXlab platform.
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triclosan enhances short chain Fatty Acid production from sludge fermentation by elevating transcriptional activity of Acidogenesis bacteria
Chemical Engineering Journal, 2020Co-Authors: Changzheng Fan, Man Zhou, Xiang Tang, Guangming Zeng, Biao Song, Rui Gong, Baowei Zhang, Weiping Xiong, Haoran Dong, Ning DingAbstract:Abstract Triclosan (TCS) is an emerging contaminant in waste activated sludge (WAS). However, the effects of TCS on WAS anaerobic fermentation is still unknown. Herein, we investigated the impacts of different TCS levels on the Short-Chain Fatty Acid (SCFA) accumulation. TCS at 100 mg/kg TSS (total suspended solids) significantly (p
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revealing the underlying mechanisms of how sodium chloride affects short chain Fatty Acid production from the cofermentation of waste activated sludge and food waste
ACS Sustainable Chemistry & Engineering, 2016Co-Authors: Jianwei Zhao, Guangming Zeng, Xiaoming Li, Dongbo Wang, Hongxue An, Qiuxiang Xu, Chang Zhang, Fei Chen, Qi YangAbstract:Recently, anaerobic cofermentation of waste activated sludge (WAS) and food waste for short chain Fatty Acid (SCFA) production has drawn growing attention. However, the details of how sodium chloride (NaCl) in food waste affects SCFA generation from the cofermentation remain largely unknown, which provides limited understanding of the cofermentation process. This work therefore aims to provide such support. Experimental results showed that the effect of NaCl on SCFA production was dosage dependent. With the increase of NaCl level from 0 to 8 g/L SCFA production increased from 367.6 to 638.5 mg chemical oxygen demand (COD)/g of volatile suspended solids (VSS). However, further increase of NaCl caused severe inhibition of SCFA production. The presence of NaCl not only accelerated the release of soluble substances from food waste and disruption of both extracellular polymers and cell envelopes in sludge but also promoted the conversion of protein released from the disintegration process, thereby causing more...
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combined effect of free nitrous Acid pretreatment and sodium dodecylbenzene sulfonate on short chain Fatty Acid production from waste activated sludge
Scientific Reports, 2016Co-Authors: Jianwei Zhao, Qi Yang, Dongbo Wang, Yiwen Liu, Qilin Wang, Yingjie Sun, Guangming ZengAbstract:Free nitrous Acid (FNA) serving as a pretreatment is an effective approach to accelerate sludge disintegration. Also, sodium dodecylbenzene sulfonate (SDBS), a type of surfactants, has been determined at significant levels in sewage sludge, which thereby affects the characteristics of sludge. Both FNA pretreatment and sludge SDBS levels can affect Short-Chain Fatty Acid (SCFA) generation from sludge anaerobic fermentation. To date, however, the combined effect of FNA pretreatment and SDBS presence on SCFA production as well as the corresponding mechanisms have never been documented. This work therefore aims to provide such support. Experimental results showed that the combination of FNA and SDBS treatment not only improved SCFA accumulation but also shortened the fermentation time. The maximal SCFA accumulation of 334.5 mg chemical oxygen demand (COD)/g volatile suspended solids (VSS) was achieved at 1.54 mg FNA/L treatment and 0.02 g/g dry sludge, which was respectively 1.79-fold and 1.41-fold of that from FNA treatment and sludge containing SDBS alone. Mechanism investigations revealed that the combined FNA pretreatment and SDBS accelerated solubilization, hydrolysis, and Acidification steps but inhibited the methanogenesis. All those observations were in agreement with SCFA enhancement.
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effect of initial ph on short chain Fatty Acid production during the anaerobic fermentation of membrane bioreactor sludge enhanced by alkyl polyglcoside
International Biodeterioration & Biodegradation, 2015Co-Authors: Jianwei Zhao, Qi Yang, Xiaoming Li, Dongbo Wang, Hongxue An, Qiuxiang Xu, Yongchao Deng, Guangming ZengAbstract:Membrane bioreactor (MBR) sludge anaerobic fermentation for short chain Fatty Acid (SCFA) production has drawn much attention as it can produce value-added product and reduce sludge volume simultaneously. However, SCFA production from sludge is always limited due to the low hydrolysis rate and rapid consumption by methanogens. In this study, an efficient and green strategy was developed by adding biosurfactant alkyl polyglycoside (APG) into MBR sludge to enhance SCFA production. Experimental results showed that the yield of SCFA reached 282.9 mg chemical oxygen demand (COD)/g volatile suspended solids (VSS) with the optimum APG dosage of 0.2 g/g dry sludge (DS), which was 4.8-fold of the blank. Furthermore, the effect of initial pH ranging from 4 to 12 on SCFA production in the presence of APG was also studied. Results showed SCFA productions from MBR sludge in the presence of APG at initial alkaline pH values were more efficient than those at Acidic and near-neutral pH values, and the optimum initial pH was 11.
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free nitrous Acid serving as a pretreatment method for alkaline fermentation to enhance short chain Fatty Acid production from waste activated sludge
Water Research, 2015Co-Authors: Jianwei Zhao, Qi Yang, Xiaoming Li, Dongbo Wang, Hongbo Chen, Yu Zhong, Guangming ZengAbstract:Abstract Alkaline condition (especially pH 10) has been demonstrated to be a promising method for Short-Chain Fatty Acid (SCFA) production from waste activated sludge anaerobic fermentation, because it can effectively inhibit the activities of methanogens. However, due to the limit of sludge solubilization rate, long fermentation time is required but SCFA yield is still limited. This paper reports a new pretreatment method for alkaline fermentation, i.e., using free nitrous Acid (FNA) to pretreat sludge for 2 d, by which the fermentation time is remarkably shortened and meanwhile the SCFA production is significantly enhanced. Experimental results showed the highest SCFA production of 370.1 mg COD/g VSS (volatile suspended solids) was achieved at 1.54 mg FNA/L pretreatment integration with 2 d of pH 10 fermentation, which was 4.7- and 1.5-fold of that in the blank (uncontrolled) and sole pH 10 systems, respectively. The total time of this integration system was only 4 d, whereas the corresponding time was 15 d in the blank and 8 d in the sole pH 10 systems. The mechanism study showed that compared with pH 10, FNA pretreatment accelerated disruption of both extracellular polymeric substances and cell envelope. After FNA pretreatment, pH 10 treatment (1 d) caused 38.0% higher substrate solubilization than the sole FNA, which indicated that FNA integration with pH 10 could cause positive synergy on sludge solubilization. It was also observed that this integration method benefited hydrolysis and Acidification processes. Therefore, more SCFA was produced, but less fermentation time was required in the integrated system.
Dongbo Wang - One of the best experts on this subject based on the ideXlab platform.
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revealing the underlying mechanisms of how sodium chloride affects short chain Fatty Acid production from the cofermentation of waste activated sludge and food waste
ACS Sustainable Chemistry & Engineering, 2016Co-Authors: Jianwei Zhao, Guangming Zeng, Xiaoming Li, Dongbo Wang, Hongxue An, Qiuxiang Xu, Chang Zhang, Fei Chen, Qi YangAbstract:Recently, anaerobic cofermentation of waste activated sludge (WAS) and food waste for short chain Fatty Acid (SCFA) production has drawn growing attention. However, the details of how sodium chloride (NaCl) in food waste affects SCFA generation from the cofermentation remain largely unknown, which provides limited understanding of the cofermentation process. This work therefore aims to provide such support. Experimental results showed that the effect of NaCl on SCFA production was dosage dependent. With the increase of NaCl level from 0 to 8 g/L SCFA production increased from 367.6 to 638.5 mg chemical oxygen demand (COD)/g of volatile suspended solids (VSS). However, further increase of NaCl caused severe inhibition of SCFA production. The presence of NaCl not only accelerated the release of soluble substances from food waste and disruption of both extracellular polymers and cell envelopes in sludge but also promoted the conversion of protein released from the disintegration process, thereby causing more...
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combined effect of free nitrous Acid pretreatment and sodium dodecylbenzene sulfonate on short chain Fatty Acid production from waste activated sludge
Scientific Reports, 2016Co-Authors: Jianwei Zhao, Qi Yang, Dongbo Wang, Yiwen Liu, Qilin Wang, Yingjie Sun, Guangming ZengAbstract:Free nitrous Acid (FNA) serving as a pretreatment is an effective approach to accelerate sludge disintegration. Also, sodium dodecylbenzene sulfonate (SDBS), a type of surfactants, has been determined at significant levels in sewage sludge, which thereby affects the characteristics of sludge. Both FNA pretreatment and sludge SDBS levels can affect Short-Chain Fatty Acid (SCFA) generation from sludge anaerobic fermentation. To date, however, the combined effect of FNA pretreatment and SDBS presence on SCFA production as well as the corresponding mechanisms have never been documented. This work therefore aims to provide such support. Experimental results showed that the combination of FNA and SDBS treatment not only improved SCFA accumulation but also shortened the fermentation time. The maximal SCFA accumulation of 334.5 mg chemical oxygen demand (COD)/g volatile suspended solids (VSS) was achieved at 1.54 mg FNA/L treatment and 0.02 g/g dry sludge, which was respectively 1.79-fold and 1.41-fold of that from FNA treatment and sludge containing SDBS alone. Mechanism investigations revealed that the combined FNA pretreatment and SDBS accelerated solubilization, hydrolysis, and Acidification steps but inhibited the methanogenesis. All those observations were in agreement with SCFA enhancement.
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effect of initial ph on short chain Fatty Acid production during the anaerobic fermentation of membrane bioreactor sludge enhanced by alkyl polyglcoside
International Biodeterioration & Biodegradation, 2015Co-Authors: Jianwei Zhao, Qi Yang, Xiaoming Li, Dongbo Wang, Hongxue An, Qiuxiang Xu, Yongchao Deng, Guangming ZengAbstract:Membrane bioreactor (MBR) sludge anaerobic fermentation for short chain Fatty Acid (SCFA) production has drawn much attention as it can produce value-added product and reduce sludge volume simultaneously. However, SCFA production from sludge is always limited due to the low hydrolysis rate and rapid consumption by methanogens. In this study, an efficient and green strategy was developed by adding biosurfactant alkyl polyglycoside (APG) into MBR sludge to enhance SCFA production. Experimental results showed that the yield of SCFA reached 282.9 mg chemical oxygen demand (COD)/g volatile suspended solids (VSS) with the optimum APG dosage of 0.2 g/g dry sludge (DS), which was 4.8-fold of the blank. Furthermore, the effect of initial pH ranging from 4 to 12 on SCFA production in the presence of APG was also studied. Results showed SCFA productions from MBR sludge in the presence of APG at initial alkaline pH values were more efficient than those at Acidic and near-neutral pH values, and the optimum initial pH was 11.
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free nitrous Acid serving as a pretreatment method for alkaline fermentation to enhance short chain Fatty Acid production from waste activated sludge
Water Research, 2015Co-Authors: Jianwei Zhao, Qi Yang, Xiaoming Li, Dongbo Wang, Hongbo Chen, Yu Zhong, Guangming ZengAbstract:Abstract Alkaline condition (especially pH 10) has been demonstrated to be a promising method for Short-Chain Fatty Acid (SCFA) production from waste activated sludge anaerobic fermentation, because it can effectively inhibit the activities of methanogens. However, due to the limit of sludge solubilization rate, long fermentation time is required but SCFA yield is still limited. This paper reports a new pretreatment method for alkaline fermentation, i.e., using free nitrous Acid (FNA) to pretreat sludge for 2 d, by which the fermentation time is remarkably shortened and meanwhile the SCFA production is significantly enhanced. Experimental results showed the highest SCFA production of 370.1 mg COD/g VSS (volatile suspended solids) was achieved at 1.54 mg FNA/L pretreatment integration with 2 d of pH 10 fermentation, which was 4.7- and 1.5-fold of that in the blank (uncontrolled) and sole pH 10 systems, respectively. The total time of this integration system was only 4 d, whereas the corresponding time was 15 d in the blank and 8 d in the sole pH 10 systems. The mechanism study showed that compared with pH 10, FNA pretreatment accelerated disruption of both extracellular polymeric substances and cell envelope. After FNA pretreatment, pH 10 treatment (1 d) caused 38.0% higher substrate solubilization than the sole FNA, which indicated that FNA integration with pH 10 could cause positive synergy on sludge solubilization. It was also observed that this integration method benefited hydrolysis and Acidification processes. Therefore, more SCFA was produced, but less fermentation time was required in the integrated system.
Jianwei Zhao - One of the best experts on this subject based on the ideXlab platform.
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revealing the underlying mechanisms of how sodium chloride affects short chain Fatty Acid production from the cofermentation of waste activated sludge and food waste
ACS Sustainable Chemistry & Engineering, 2016Co-Authors: Jianwei Zhao, Guangming Zeng, Xiaoming Li, Dongbo Wang, Hongxue An, Qiuxiang Xu, Chang Zhang, Fei Chen, Qi YangAbstract:Recently, anaerobic cofermentation of waste activated sludge (WAS) and food waste for short chain Fatty Acid (SCFA) production has drawn growing attention. However, the details of how sodium chloride (NaCl) in food waste affects SCFA generation from the cofermentation remain largely unknown, which provides limited understanding of the cofermentation process. This work therefore aims to provide such support. Experimental results showed that the effect of NaCl on SCFA production was dosage dependent. With the increase of NaCl level from 0 to 8 g/L SCFA production increased from 367.6 to 638.5 mg chemical oxygen demand (COD)/g of volatile suspended solids (VSS). However, further increase of NaCl caused severe inhibition of SCFA production. The presence of NaCl not only accelerated the release of soluble substances from food waste and disruption of both extracellular polymers and cell envelopes in sludge but also promoted the conversion of protein released from the disintegration process, thereby causing more...
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combined effect of free nitrous Acid pretreatment and sodium dodecylbenzene sulfonate on short chain Fatty Acid production from waste activated sludge
Scientific Reports, 2016Co-Authors: Jianwei Zhao, Qi Yang, Dongbo Wang, Yiwen Liu, Qilin Wang, Yingjie Sun, Guangming ZengAbstract:Free nitrous Acid (FNA) serving as a pretreatment is an effective approach to accelerate sludge disintegration. Also, sodium dodecylbenzene sulfonate (SDBS), a type of surfactants, has been determined at significant levels in sewage sludge, which thereby affects the characteristics of sludge. Both FNA pretreatment and sludge SDBS levels can affect Short-Chain Fatty Acid (SCFA) generation from sludge anaerobic fermentation. To date, however, the combined effect of FNA pretreatment and SDBS presence on SCFA production as well as the corresponding mechanisms have never been documented. This work therefore aims to provide such support. Experimental results showed that the combination of FNA and SDBS treatment not only improved SCFA accumulation but also shortened the fermentation time. The maximal SCFA accumulation of 334.5 mg chemical oxygen demand (COD)/g volatile suspended solids (VSS) was achieved at 1.54 mg FNA/L treatment and 0.02 g/g dry sludge, which was respectively 1.79-fold and 1.41-fold of that from FNA treatment and sludge containing SDBS alone. Mechanism investigations revealed that the combined FNA pretreatment and SDBS accelerated solubilization, hydrolysis, and Acidification steps but inhibited the methanogenesis. All those observations were in agreement with SCFA enhancement.
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effect of initial ph on short chain Fatty Acid production during the anaerobic fermentation of membrane bioreactor sludge enhanced by alkyl polyglcoside
International Biodeterioration & Biodegradation, 2015Co-Authors: Jianwei Zhao, Qi Yang, Xiaoming Li, Dongbo Wang, Hongxue An, Qiuxiang Xu, Yongchao Deng, Guangming ZengAbstract:Membrane bioreactor (MBR) sludge anaerobic fermentation for short chain Fatty Acid (SCFA) production has drawn much attention as it can produce value-added product and reduce sludge volume simultaneously. However, SCFA production from sludge is always limited due to the low hydrolysis rate and rapid consumption by methanogens. In this study, an efficient and green strategy was developed by adding biosurfactant alkyl polyglycoside (APG) into MBR sludge to enhance SCFA production. Experimental results showed that the yield of SCFA reached 282.9 mg chemical oxygen demand (COD)/g volatile suspended solids (VSS) with the optimum APG dosage of 0.2 g/g dry sludge (DS), which was 4.8-fold of the blank. Furthermore, the effect of initial pH ranging from 4 to 12 on SCFA production in the presence of APG was also studied. Results showed SCFA productions from MBR sludge in the presence of APG at initial alkaline pH values were more efficient than those at Acidic and near-neutral pH values, and the optimum initial pH was 11.
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free nitrous Acid serving as a pretreatment method for alkaline fermentation to enhance short chain Fatty Acid production from waste activated sludge
Water Research, 2015Co-Authors: Jianwei Zhao, Qi Yang, Xiaoming Li, Dongbo Wang, Hongbo Chen, Yu Zhong, Guangming ZengAbstract:Abstract Alkaline condition (especially pH 10) has been demonstrated to be a promising method for Short-Chain Fatty Acid (SCFA) production from waste activated sludge anaerobic fermentation, because it can effectively inhibit the activities of methanogens. However, due to the limit of sludge solubilization rate, long fermentation time is required but SCFA yield is still limited. This paper reports a new pretreatment method for alkaline fermentation, i.e., using free nitrous Acid (FNA) to pretreat sludge for 2 d, by which the fermentation time is remarkably shortened and meanwhile the SCFA production is significantly enhanced. Experimental results showed the highest SCFA production of 370.1 mg COD/g VSS (volatile suspended solids) was achieved at 1.54 mg FNA/L pretreatment integration with 2 d of pH 10 fermentation, which was 4.7- and 1.5-fold of that in the blank (uncontrolled) and sole pH 10 systems, respectively. The total time of this integration system was only 4 d, whereas the corresponding time was 15 d in the blank and 8 d in the sole pH 10 systems. The mechanism study showed that compared with pH 10, FNA pretreatment accelerated disruption of both extracellular polymeric substances and cell envelope. After FNA pretreatment, pH 10 treatment (1 d) caused 38.0% higher substrate solubilization than the sole FNA, which indicated that FNA integration with pH 10 could cause positive synergy on sludge solubilization. It was also observed that this integration method benefited hydrolysis and Acidification processes. Therefore, more SCFA was produced, but less fermentation time was required in the integrated system.
Kevin J. Yarema - One of the best experts on this subject based on the ideXlab platform.
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pharmacological physiochemical and drug relevant biological properties of short chain Fatty Acid hexosamine analogues used in metabolic glycoengineering
Molecular Pharmaceutics, 2018Co-Authors: Christopher T Saeui, Lingshu Liu, Esteban Urias, Justin Morrissettemcalmon, Rahul Bhattacharya, Kevin J. YaremaAbstract:In this study, we catalog structure activity relationships (SAR) of several short chain Fatty Acid (SCFA)-modified hexosamine analogues used in metabolic glycoengineering (MGE) by comparing in silico and experimental measurements of physiochemical properties important in drug design. We then describe the impact of these compounds on selected biological parameters that influence the pharmacological properties and safety of drug candidates by monitoring P-glycoprotein (Pgp) efflux, inhibition of cytochrome P450 3A4 (CYP3A4), hERG channel inhibition, and cardiomyocyte cytotoxicity. These parameters are influenced by length of the SCFAs (e.g., acetate vs n-butyrate), which are added to MGE analogues to increase the efficiency of cellular uptake, the regioisomeric arrangement of the SCFAs on the core sugar, the structure of the core sugar itself, and by the type of N-acyl modification (e.g., N-acetyl vs N-azido). By cataloging the influence of these SAR on pharmacological properties of MGE analogues, this stud...
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short chain Fatty Acid modified hexosamine for tissue engineering osteoarthritic cartilage
Tissue Engineering Part A, 2013Co-Authors: Jeannine M Coburn, Udayanath Aich, Kevin J. Yarema, Rahul Bhattacharya, Nicholas Bernstein, Clifton O Bingham, Jennifer H ElisseeffAbstract:Inflammation and tissue degeneration play key roles in numerous rheumatic diseases, including osteoarthritis (OA). Efforts to reduce and effectively repair articular cartilage damage in an osteoarthritic environment are limited in their success due to the diseased environment. Treatment strategies focused on both reducing inflammation and increasing tissue production are necessary to effectively treat OA from a tissue-engineering perspective. In this work, we investigated the anti-inflammatory and tissue production capacity of a small molecule 3,4,6-O-tributanoylated-N-acetylglucosamine (3,4,6-O-Bu3GlcNAc) previously shown to inhibit the nuclear factor κB (NFκB) activity, a key transcription factor regulating inflammation. To mimic an inflammatory environment, chondrocytes were stimulated with interleukin-1β (IL-1β), a potent inflammatory cytokine. 3,4,6-O-Bu3GlcNAc exposure decreased the expression of NFκB target genes relevant to OA by IL-1β-stimulated chondrocytes after 24 h of exposure. The capacity of 3,4,6-O-Bu3GlcNAc to stimulate extracellular matrix (ECM) accumulation by IL-1β-stimulated chondrocytes was evaluated in vitro utilizing a three-dimensional hydrogel culturing system. After 21 days, 3,4,6-O-Bu3GlcNAc exposure induced quantifiable increases in both sulfated glycosaminoglycan and total collagen. Histological staining for proteoglycans and type II collagen confirmed these findings. The increased ECM accumulation was not due to the hydrolysis products of the small molecule, n-butyrate and N-acetylglucosamine (GlcNAc), as the isomeric 1,3,4-O-tributanoylated N-acetylglucosamine (1,3,4-O-Bu3GlcNAc) did not elicit a similar response. These findings demonstrate that a novel butanoylated GlcNAc derivative, 3,4,6-O-Bu3GlcNAc, has the potential to stimulate new tissue production and reduce inflammation in IL-1β-induced chondrocytes with utility for OA and other forms of inflammatory arthritis.
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Development of delivery methods for carbohydrate-based drugs: controlled release of biologically-active short chain Fatty Acid-hexosamine analogs
Glycoconjugate Journal, 2010Co-Authors: Udayanath Aich, M. Adam Meledeo, Srinivasa-gopalan Sampathkumar, Mark B. Jones, Christopher A. Weier, Sung Yun Chung, Benjamin C. Tang, Ming Yang, Justin Hanes, Kevin J. YaremaAbstract:Carbohydrates are attractive candidates for drug development because sugars are involved in many, if not most, complex human diseases including cancer, immune dysfunction, congenital disorders, and infectious diseases. Unfortunately, potential therapeutic benefits of sugar-based drugs are offset by poor pharmacologic properties that include rapid serum clearance, poor cellular uptake, and relatively high concentrations required for efficacy. To address these issues, pilot studies are reported here where ‘Bu_4ManNAc’, a short chain Fatty Acid-monosaccharide hybrid molecule with anti-cancer activities, was encapsulated in polyethylene glycol-sebacic Acid (PEG-SA) polymers. Sustained release of biologically active compound was achieved for over a week from drug-laden polymer formulated into microparticles thus offering a dramatic improvement over the twice daily administration currently used for in vivo studies. In a second strategy, a tributanoylated ManNAc analog (3,4,6- O -Bu_3ManNAc) with anti-cancer activities was covalently linked to PEG-SA and formulated into nanoparticles suitable for drug delivery; once again release of biologically active compound was demonstrated.
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short chain Fatty Acid hexosamine cancer prodrugs the sugar matters
Drugs of The Future, 2006Co-Authors: Srinivasa-gopalan Sampathkumar, Christopher T Campbell, Christopher Weier, Kevin J. YaremaAbstract:This review describes Short-Chain Fatty Acid (SCFA)-sugar hybrids, exemplified by the lead compound But 4 ManNAc where n-butyrate is linked to N-acetyl-D-mannosamine (ManNAc) in a single molecule, that merge two emerging modes of cancer therapy First, n-butyrate is a histone deacetylase (HDAC) inhibitor that remodels chromatin, thereby influencing patterns of gene expression to 'make bad cells go good'. Second, ManNAc is the dedicated precursor for sialic Acid biosynthesis, a sugar that is gaining increasing recognition as an important modulator of cell fate, including apoptosis, proliferation and differentiation. Herein we describe how, when combined with n-butyrate, ManNAc augments the epigenetic activity of the HDAC inhibitor to achieve sugar-dependent killing of cancer cells in vitro. Looking forward to the translation of this class of compounds into the clinic, we then discuss how the poor pharmacological properties of the individual n-butyrate and ManNAc moieties are dramatically improved by combination in a single molecule, where they function as mutual prodrugs. Finally, we conclude by outlining how But 4 ManNAc represents a versatile platform for future drug development efforts.
Henry J Binder - One of the best experts on this subject based on the ideXlab platform.
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role of colonic short chain Fatty Acid transport in diarrhea
Annual Review of Physiology, 2010Co-Authors: Henry J BinderAbstract:Short-Chain Fatty Acids (SCFA) are the major anion in stool and are synthesized from nonabsorbed carbohydrate by the colonic microbiota. Nonabsorbed carbohydrate are not absorbed in the colon and induce an osmotically mediated diarrhea; in contrast, SCFA are absorbed by colonic epithelial cells and stimulate Na-dependent fluid absorption via a cyclic AMP-independent process involving apical membrane Na-H, SCFA-HCO(3), and Cl-SCFA exchanges. SCFA production represents an adaptive process to conserve calories, fluid, and electrolytes. Inhibition of SCFA synthesis by antibiotics and administration of PEG, a substance that is not metabolized by colonic microbiota, both result in diarrhea. In contrast, increased production of SCFA as a result of providing starch that is relatively resistant to amylase digestion [so-called resistant starch (RS)] to oral rehydration solution (RS-ORS) improves the efficacy of ORS and represents an important approach to improve the effectiveness of ORS in the treatment of acute diarrhea in children under five years of age.
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role of short chain Fatty Acids in colonic hco3 secretion
American Journal of Physiology-gastrointestinal and Liver Physiology, 2005Co-Authors: Sadasivan Vidyasagar, Henry J Binder, Christian Barmeyer, John P Geibel, Vazhaikkurichi M RajendranAbstract:Luminal isobutyrate, a relatively poor metabolized Short-Chain Fatty Acid (SCFA), induces HCO3 secretion via a Cl-independent, DIDS-insensitive, carrier-mediated process as well as inhibiting both ...