Insights into the mechanisms driving microbial community succession during pepper fermentation: Roles of microbial interactions and endogenous environmental changes.

Elucidating the driving mechanism of microbial community succession during pepper fermentation contributes to establishing efficient fermentation regulation strategies. This study utilized three-generation high-throughput sequencing technology, microbial co-occurrence network analysis, and random forest analysis to reveal microbial community succession processes and driving mechanisms during pepper fermentation. The results showed that more positive correlations than negative correlations were observed among microorganisms, with positive correlation proportions of 60 %, 51.03 %, and 71.43 % between bacteria and bacteria, fungi and fungi, and bacteria and fungi in sipingtou peppers, and 69.23 %, 54.93 %, and 79.44 % in zhudachang peppers, respectively. Microbial interactions, mainly among Weissella hellenica, Lactobacillus plantarum, Hanseniaspora opuntiae, and Kazachstania humillis, could drive bacterial and fungal community succession. Notably, the bacterial community successions during the fermentation of two peppers were similar, showing the transition from Leuconostoc pseudomesenteroides, Lactococcus lactis, Weissella ghanensis to Weissella hellenica and Lactobacillus plantarum. However, the fungal community successions in the two fermented peppers differed significantly, and the differential biomarkers were Dipodascus geotrichum and Kazachstania humillis. Differences in autochthonous microbial composition and inherent constituents brought by pepper varieties resulted in different endogenous environmental changes, mainly in fructose, malic acid, and citric acid. Furthermore, endogenous environmental factors could also drive microbial community succession, with succinic acid, lactic acid, and malic acid being the main potential drivers of bacterial community succession, whereas fructose, glucose, and succinic acid were the main drivers of fungal community succession. These results will provide insights into controlling fermentation processes by raw material combinations, optimization of environmental parameters, and microbial interactions.

Enhancing wine ester biosynthesis in mixed Hanseniaspora uvarum/Saccharomyces cerevisiae fermentation by nitrogen nutrient addition.

The dynamic changes of wine ester production during mixed fermentation with Hanseniaspora uvarum Yun268 and Saccharomyces cerevisiae F5 was investigated at different levels and timings of nitrogen nutrient addition. Nitrogen additions were performed by supplementing yeast assimilable nitrogen (YAN) into a synthetic grape must with defined composition. Ester precursors and extracellular metabolites involved in ester synthesis were analyzed throughout the fermentation. Results showed that nitrogen additions covering 50-200 mg/L YAN at the point of yeast inoculation slightly affected yeast competition and ester profiles. Interestingly, when YAN was supplemented in the mid-stage, the survival of H. uvarum Yun268 was enhanced, resulting in more than a 2-fold increase in the levels of higher alcohol acetates compared to that at the initial stage. Furthermore, carbon fluxes may be redistributed in the central pathway, which contributed to the production of medium-chain fatty acids and eventually triggered a 1.2-fold elevation in corresponding ethyl ester levels.

Efficacy of clofazimine-modified cyclodextrin against Mycobacterium avium complex in human macrophages.

Clofazimine, a water insoluble substituted iminophenazine derivative with anti-mycobacterial and anti-inflammatory activity, is recommended by the WHO for the treatment of leprosy. It is also active against disseminated Mycobacterium avium complex (MAC) disease in HIV-infected patients. Recently, we achieved a 4000-fold increase of clofazimine water solubility using a novel modified clofazimine-cyclodextrin complex synthesized and patented by our group [Wasserlösliche, Iminiophenazinderivate enthaltende pharmazeutische Zusammensetzungen, deren Herstellung und Verwendung, German Patent, DE19814814C2]. In this paper we examine the activity of this complex against MAC in human macrophages, and evaluate its cytotoxicity. MAC-infected macrophages were treated for 24h with free or complexed clofazimine. The in vitro minimum inhibitory concentrations of both free and complexed clofazimine were 0.1 microg/ml. Free and complexed clofazimine inhibited the growth of MAC inside macrophages to a similar extent, while modified cyclodextrin alone had no observable effects on MAC or macrophages. Complexed clofazimine was not toxic to cells at concentrations effective against MAC. The TD(50) of the modified cyclodextrin in THP-1 cell line was 297 microg/ml.

Efficacy of clofazimine - modified cyclodextrin against Mycobacterium avium complex in human macrophages

Clofazimine, a water insoluble substituted iminophenazine derivative with anti-mycobacterial and anti-inflammatory activity, is recommended by the WHO for the treatment of leprosy. It is also active against disseminated Mycobacterium avium complex (MAC) disease in HIV-infected patients. Recently, we achieved a 4000-fold increase of clofazimine water solubility using a novel modified clofazimine-cyclodextrin complex synthesized and patented by our group [Wasserlösliche, Iminiophenazinderivate enthaltende pharmazeutische Zusammensetzungen, deren Herstellung und Verwendung, German Patent, DE19814814C2]. In this paper we examine the activity of this complex against MAC in human macrophages, and evaluate its cytotoxicity. MAC-infected macrophages were treated for 24h with free or complexed clofazimine. The in vitro minimum inhibitory concentrations of both free and complexed clofazimine were 0.1 microg/ml. Free and complexed clofazimine inhibited the growth of MAC inside macrophages to a similar extent, while modified cyclodextrin alone had no observable effects on MAC or macrophages. Complexed clofazimine was not toxic to cells at concentrations effective against MAC. The TD(50) of the modified cyclodextrin in THP-1 cell line was 297 microg/ml.

The use of a potential-sensitive cyanine dye for studying ion-dependent electrogenic renal transport of organic solutes. Uptake of L-malate and D-malate by luminal-membrane vesicles.

The mechanisms of uptake of dicarboxylic acids by rabbit renal luminal-membrane vesicles were studied by the use of filtration and spectrophotometric techniques as described in an accompanying paper [Kragh-Hansen, Jørgensen & Sheikh (1982) Biochem. J.208, 359-368]. Addition of l- or d-malate to dye-membrane-vesicle suspensions in the presence of Na(+) gradients (extravesicular>intravesicular) resulted in spectral curves indicative of depolarization events. The renal uptake of dicarboxylic acids was dependent on the type of Na(+)-salt anion present and could be correlated with the ability of the anions to penetrate biological membranes (i.e. Cl(-)>SO(4) (2-)>gluconate). Identical results were obtained by a filtration technique with Sartorius membrane filters. The results indicate that the dicarboxylic acids are taken up by the membrane vesicles in an electrically positive form (i.e. Na(+)/substrate coupling ratio 3:1) by an Na(+)-dependent transport system. This proposal was further supported by spectrophotometric experiments with various ionophores such as valinomycin, gramicidin and nigericin. The absorbance changes associated with simultaneous addition of l- and d-malate and spectrophotometric competition studies revealed that the two isomers are taken up by a common transport system. Spectral changes of the dye induced by addition of increasing concentrations of l- or d-malate indicated that the transport system favours the unphysiological d-form rather than the l-form of malate. Furthermore, it was observed that the affinity of both isomers for the transport system was dependent on the concentration of Na(+) in the medium.

Metabolism of carbon sources by Mycobacterium leprae: a preliminary report.

Glucose was established in Mycobacterium leprae by glycolysis and the hexose monophosphate pathway (30 %)-pentose phosphate pathway. Glycerol was also catabolised to CO2 at a similar rate to glucose. Key in cell-free extracts as enzymes for M. leprae.