Introduction: Short-Chain Fatty Acids (SCFA) are products of intestinal microbial metabolism that can reach the brain and alter microglia in health and disease contexts. However, data are conflicting on the effect of acetate, the most abundant SCFA in the blood, in these cells. Objective: The authors aimed to investigate acetate as a modulator of the inflammatory response in microglia stimulated with LPS. Method: The authors used an immortalized cell line, C8-B4, and primary cells for in vitro treatments with acetate and LPS. Cell viability was analyzed by MTT, cytokine by RT-PCR, ELISA, and flow cytometry. The authors also performed in vivo and in silico analyses to study the role of acetate and the TNF-α contribution to the development of Experimental Autoimmune Encephalomyelitis (EAE). Results: Acetate co-administered with LPS was able to exacerbate the production of pro-inflammatory cytokines at gene and protein levels in cell lines and primary culture of microglia. However, the same effects were not observed when acetate was administered alone or as pretreatment, prior to the LPS stimulus. Additionally, pharmacological inhibition of histone deacetylase concomitantly with acetate and LPS led to decreased TNF-α production. In silico analysis showed a crucial role of the TNF-α pathway in EAE development. Moreover, acetate administration in vivo during the initial phase of EAE led to a better disease outcome and reduced TNF-α production. Conclusion: Treatment with acetate was able to promote the production of TNF-α in a concomitant LPS stimulus of microglia. However, the immune modulation of microglia by acetate pretreatment may be a component in the generation of future therapies for neurodegenerative diseases.

AcpA has been previously characterized as a high-affinity transporter essential for the uptake and use of acetate as sole carbon source in Aspergillus nidulans. Here, we follow the expression profile of AcpA and define its substrate specificity. AcpA-mediated acetate transport is detected from the onset of conidiospore germination, peaks at the time of germ tube emergence, and drops to low basal levels in germlings and young mycelia, where a second acetate transporter is also becoming apparent. AcpA activity also responds to acetate presence in the growth medium, but is not subject to either carbon or nitrogen catabolite repression. Short-chain monocarboxylates (benzoate, formate, butyrate and propionate) inhibit AcpA-mediated acetate transport with apparent inhibition constants (Ki) of 16.89±2.12, 9.25±1.01, 12.06±3.29 and 1.44±0.13mM, respectively. AcpA is also shown not to be directly involved in ammonia export, as proposed for its Saccharomyces cerevisiae homologue Ady2p. In the second part of this work, we search for the unknown acetate transporter expressed in mycelia, and for other transporters that might contribute to acetate uptake. In silico analysis, genetic construction of relevant null mutants, and uptake assays, reveal that the closest AcpA homologue (AN1839), named AcpB, is the 'missing' secondary acetate transporter in mycelia. We also identify two major short-chain carboxylate (lactate, succinate, pyruvate and malate) transporters, named JenA (AN6095) and JenB (AN6703), which however are not involved in acetate uptake. This work establishes a framework for further exploiting acetate and carboxylate transport in filamentous ascomycetes.

Opportunistic pathogens such as Candida species can use carboxylic acids, like acetate and lactate, to survive and successfully thrive in different environmental niches. These nonfermentable substrates are frequently the major carbon sources present in certain human body sites, and their efficient uptake by regulated plasma membrane transporters plays a critical role in such nutrient-limited conditions. Here, we cover the physiology and regulation of these proteins and their potential role in Candida virulence. This review also presents an evolutionary analysis of orthologues of the Saccharomyces cerevisiae Jen1 lactate and Ady2 acetate transporters, including a phylogenetic analysis of 101 putative carboxylate transporters in twelve medically relevant Candida species. These proteins are assigned to distinct clades according to their amino acid sequence homology and represent the major carboxylic acid uptake systems in yeast. While Jen transporters belong to the sialate:H symporter (SHS) family, the Ady2 homologue members are assigned to the acetate uptake transporter (AceTr) family. Here, we reclassify the later members as ATO (acetate transporter ortholog). The new nomenclature will facilitate the study of these transporters, as well as the analysis of their relevance for Candida pathogenesis.

Great attention is focused on the microbial treatment of metal contaminated environments. Three bacterial strains, 1C2, 1ZP4 and EC30, belonging to genera Cupriavidus, Sphingobacterium and Alcaligenes, respectively, showing high tolerance to Zn and Cd, up to concentrations of 1000 ppm, were isolated from a contaminated area in Northern Portugal. Their contribution to Zn and Cd removal from aqueous streams using immobilised alginate, pectate and a synthetic cross-linked polymer was assessed. In most cases, matrices with immobilised bacteria showed better metal removal than the non-inoculated material alone. For the immobilisation with all the polymers, 1C2 was the strain that increased the removal of Zn the most, whereas EC30 was the most promising for Cd removal, especially when combined with the synthetic polymer with up to a ca. 11-fold increase in metal removal when compared to the polymer alone. Removal of individual metals from binary mixtures showed that there was differential immobilisation. There was greater removal of Cd than Zn (removals up to 40% higher than those showed for Zn). The results show that metal contaminated environments constitute a reservoir of microorganisms resistant/tolerant to heavy metals that have the capacity to be exploited in bioremediation strategies. Capsule immobilisation of bacteria in the naturally occurring alginate and pectate and in a synthetic cross-linked polymer increased the Zn and Cd removal abilities from single and binary contaminated waters; the applications with the synthetic polymer were the most promising for Cd and Zn removal in single and binary mixtures.

Fluoroquinolones constitute a group of emerging pollutants and their occurrence in different environmental compartments is becoming object of increasing public concern due to their ecotoxicological effects and the potential to develop resistant bacteria. This study aimed to investigate the biodegradation of moxifloxacin (MOX), for which studies in the literature are very scarce. An activated sludge (AS) consortium and three bacterial strains able to degrade fluoroaromatic compounds e strains F11, FP1 and S2 e were tested. Biodegradation studies were conducted using acetate as a bulk carbon source. Strain F11 showed the highest biodegradation capacity, being able to completely consume and dehalogenate 7.5 mM of the target antibiotic when daily co-supplemented with acetate present as a readily degradable organic substrate in wastewaters. MOX could be used by strain F11 as a sole nitrogen source but the presence of an external nitrogen source in the culture medium was essential for complete biodegradation. Strain F11 was capable of completely consuming MOX in a range between 2 and 11 mM, although stoichiometric fluoride release was not obtained for the highest tested concentration. The antibacterial activity of residual MOX and of the metabolic products potentially resultant from the biodegradation process was investigated by agar diffusion tests, demonstrating that MOX biodegradation is associated with the elimination of the antibacterial properties of the target antibiotic and of the produced metabolites, which is an important result, as the activity of antibiotics and/or their metabolites in the environment, even at low levels, may lead to the development of resistant bacterial strains. Overall, the results obtained in this study suggest that strain F11 is a promising microorganism for the treatment of waters contaminated with MOX, where it could be used for bioaugmentation/bioremediation purposes. To the best of our knowledge, this is the first study reporting complete removal and dehalogenation of MOX by a single microorganism.

Colorectal cancer (CRC) is a leading cause of death worldwide. Conventional therapies are available with varying effectiveness. Acetate, a short-chain fatty acid produced by human intestinal bacteria, triggers mitochondria-mediated apoptosis preferentially in CRC but not in normal colonocytes, which has spurred an interest in its use for CRC prevention/therapy. We previously uncovered that acetate-induced mitochondrial-mediated apoptosis in CRC cells is significantly enhanced by the inhibition of the lysosomal protease cathepsin D (CatD), which indicates both mitochondria and the lysosome are involved in the regulation of acetate-induced apoptosis. Herein, we sought to determine whether mitochondrial function affects CatD apoptotic function. We found that enhancement of acetate-induced apoptosis by CatD inhibition depends on oligomycin A-sensitive respiration. Mechanistically, the potentiating effect is associated with an increase in cellular and mitochondrial superoxide anion accumulation and mitochondrial mass. Our results provide novel clues into the regulation of CatD function and the effect of tumor heterogeneity in the outcome of combined treatment using acetate and CatD inhibitors.

Products of exocrine glands modulate the behavior of social in sects. Among the exocrine glands, the function of intramandibular glands has not been well characterized in social Hymenoptera. To study the effects of exocrine gland secretions on the behavior of the ant, Neoponera villosa, identification of cuticular and intramandibular gland compounds was performed. Fifteen different compounds were identified in workers and queens of N. villosa. Linear alkanes C26, C27, C28, C30 and C36, as well as the methyl alkanes 13-, 11- MeC28, 3 MeC29, 13-, 11- MeC32, 13-, 11- MeC33, 13- MeC36, 13,17-; 15,19-DiMeC37 and 18-, 17-, 13-MeC38 and esters triacontyl acetate were found on the body and mandible surface of both workers and queens. The sterols, cholesterol and sitosterol were found only in the mandibles, with cholesterol present in both workers and queens, and sitosterol present only in queens. The results suggest that intramandibular gland compounds of N. villosa may play a role in worker activity. The presence of hydrocarbons and cholesterol in workers and sitosterol in the mandible of queens may be associated with caste profile.

ABSTRACT - The aim of the study was evaluate the production potential for methane (CH4) and carbon dioxide (CO2), short-chain fatty acids, ammonia nitrogen (N-NH3) and pH by semiautomated technique in vitro from biodiesel byproducts cottonseed cake (Gossypium hirsutum), castor bean (Ricinus communis), moringa cake (Moringa oleifera), jatropha cake (Jatropha curcas) and sunflower cake (Helianthus annuus) substituting corn silage in increasing levels, 0, 30, 50 and 70%. The experimental design used was completely randomized in a 5 x 4 factorial arrangement (byproducts and substitution levels). The inoculum for the in vitro incubations was obtained from three Holstein cows with rumen fistulas. In the experiment, the conditions were verified for the differences in potential gas production among the ingredients. The byproduct of cotton was the ingredient with the greatest potential to produce acetate, butyrate, CO2 and CH4. The byproduct of moringa had the lowest potential for the production of acetate, butyrate, CO2 and CH4 from in vitro degraded dry matter and a greater potential for the production of propionate. Among the byproducts studied, moringa was distinguished for promoting mitigation of CH4 and obtaining levels of pH and N-NH3 satisfactory for maximum rumen fermentation; thus, it is recommended the byproduct of moringa to replace corn silage because reduces environmental impact without impairing in vitro rumen fermentation. RESUMO - O objetivo do estudo foi avaliar o potencial de produção de metano (CH4), dióxido de carbono (CO2), ácidos graxos de cadeia curta, nitrogênio amoniacal (N-NH3) e pH pela técnica semiautomática técnica in vitro a partir de coprodutos do biodiesel como torta de algodão (Gossypium hirsutum), torta de mamona (Ricinus communis), torta de moringa (Moringa oleifera), torta de pinhão manso (Jatropha curcas) e torta girassol (Helianthus annuus) em substituição a silagem de milho em níveis crescentes, 0, 30, 50 e 70%. O delineamento foi inteiramente casualizado, em um arranjo fatoria 5 x 4 (coprodutos and níveis de substituição). O inóculo para as incubações in vitro foi obtido a partir de três vacas da raça Holandesa com fístulas ruminais. No experimento, as condições foram verificadas para observer as diferenças na potencial produção de gás entre os ingredientes. O coproduto de algodão foi o ingrediente com o maior potencial para produção de acetato, butirato, CO2 e CH4. O coproduto de Moringa teve o menor potencial para a produção de acetato, butirato, CO2 e CH4 e digestibilidade in vitro da matéria seca e um maior potencial para a produção de propionato. Entre os coprodutos estudados, a moringa destacou-se pela promoção da mitigação de CH4 e obtenção de níveis de pH e N-NH3 satisfatórias para a fermentação máxima no rúmen. Assim, recomenda-se utilizar o coproduto de moringa para substituir a silagem de milho, pois reduz o impacto ambiental sem prejudicar a fermentação ruminal in vitro.

The secretion of metabolites with antimicrobial activity is one of the strategies employed by bacteria in response to negative stimuli promoted during interspecies competition. In its stationary phase Pseudomonas aeruginosa and Escherichia coli can synthesize diffusible exometabolites whose action is to mutually inhibit the exposed cells, ensuring the balance of both populations in a given place. The former may have an advantage due to the production of pyocyanine. However, the excretion of indol and acetate by E. coli can balance this advantage. This study aimed to detect the influence of indol and acetate on the synthesis of pyocyanin and adhesion of P. aeruginosa, as well as the action of pyocyanin on viable E. coli cells, as well as its adhesion. For this purpose, in vitro tests were conducted to determine the Minimum Inhibitory Concentration (MIC), extraction and quantification of pyocyanin and adhesion by the violet crystal method. The synthesis of piocyanin by Pseudomonas aeruginosa was reduced by up to 50% in the presence of indol. On the other hand, no change in pigment production was observed in the presence of acetate, alone or associated with concentrations lower than 0.5 mM, reflecting an increase of more than 20% in piocyanine production. Indol was also effective in reducing the adhesion of Pseudomonas aeruginosa cells compared to control. For the E. coli strains, the MIC of pyocyanin was 37.5 µg/mL, also reducing cell adhesion. It was observed that despite the inhibition having occurred, no exometabolite promoted biocidal effect in the evaluated strains. The results contribute to the understanding of the ecological mechanisms that occur during the competition between these two bacterial species in aqueous medium.