The Role of Fatty Acid Metabolism in Drug Tolerance of Mycobacterium tuberculosis

Understanding the mechanisms underlying M. tuberculosis adaptive strategies to achieve drug tolerance is crucial for the identification of new targets and the development of new drugs. Here, we show that acetate medium triggers a drug-tolerant state in M. tuberculosis when challenged with antituberculosis (anti-TB) drugs.

Immobilization of Aspergillus oryzae DSM 1863 for l-Malic Acid Production

Whole-cell immobilization by entrapment in natural polymers can be a tool for morphological control and facilitate biomass retention. In this study, the possibility of immobilizing the filamentous fungus Aspergillus oryzae for l-malic acid production was evaluated with the two carbon sources acetate and glucose. A. oryzae conidia were entrapped in alginate, agar, and κ-carrageenan and production was monitored in batch processes in shake flasks and 2.5-L bioreactors. With glucose, the malic acid concentration after 144 h of cultivation using immobilized particles was mostly similar to the control with free biomass. In acetate medium, production with immobilized conidia of A. oryzae in shake flasks was delayed and titers were generally lower compared to cultures with free mycelium. While all immobilization matrices were stable in glucose medium, disintegration of bead material and biomass detachment in acetate medium was observed in later stages of the fermentation. Still, immobilization proved advantageous in bioreactor cultivations with acetate and resulted in increased malic acid titers. This study is the first to evaluate immobilization of A. oryzae for malic acid production and describes the potential but also challenges regarding the application of different matrices in glucose and acetate media.

Identification of Fatty Acid, Lipid and Polyphenol Compounds from Prunus armeniaca L. Kernel Extracts

Apart from its essential oil, Prunus armeniaca L. kernel extract has received only scarce attention. The present study aimed to describe the lipid and polyphenolic composition of the dichloromethane, chloroform, ethyl acetate, and ethanol extracts on the basis of hot extraction, performing analysis by gas chromatography and high-performance liquid chromatography coupled with mass spectrometry. A total of 6 diacylglycerols (DAGs) and 18 triacylglycerols (TAGs) were detected as being present in all extracts, with the predominance of OLL (dilinoleyl-olein), OOL (dioleoyl-linolein), and OOO (triolein), with percentages ranging from 19.0–32.8%, 20.3–23.6%, and 12.1–20.1%, respectively. In further detail, the extraction with ethyl acetate (medium polarity solvent) gave the highest signal for all peaks, followed by chloroform and dichloromethane (more apolar solvent), while the extraction with ethanol (polar solvent) was the least efficient. Ethanol showed very poor signal for the most saturated TAGs, while dichloromethane showed the lowest percentages of DAGs. Accordingly, the screening of the total fatty acid composition revealed the lowest percentage of linoleic acid (C18:2n6) in the dichloromethane extract, which instead contained the highest amount (greater than 60%) of oleic acid (C18:1n9). Polyphenolic compounds with pharmacological effects (anti-tumor, anti-coagulant, and inflammatory), such as coumarin derivative and amygdalin, occurred at a higher amount in ethyl acetate and ethanol extracts.

Expression of Talaromyces marneffei acuM and acuK Genes in Gluconeogenic Substrates and Various Iron Concentrations

Talaromyces marneffei is an opportunistic, dimorphic fungal pathogen that causes a disseminated infection in people with a weakened immunological status. The ability of this fungus to acquire nutrients inside the harsh environment of the macrophage phagosome is presumed to contribute to its pathogenicity. The transcription factors AcuM and AcuK are known to regulate gluconeogenesis and iron acquisition in Aspergillus fumigatus. This study demonstrated that they are also involved in both of these processes in the dimorphic fungus T. marneffei. Expression of acuM and acuK genes was determined by real time-polymerase chain reaction (RT-PCR) on the cells grown in media containing gluconeogenic substrates and various iron concentrations. We found that the acuM and acuK transcript levels were sequentially reduced when growing the fungus in increasing amounts of iron. The acuM transcript was upregulated in the gluconeogenic condition, while the acuK transcript showed upregulation only in the acetate medium in the yeast phase. These results suggest the involvement of acuM and acuK in gluconeogenesis and iron homeostasis in T. marneffei.

Spectrum of hemoglobinopathies in a tertiary care centre

Background: Thalassemia and other structural hemoglobinopathies are the most common single gene disorders throughout the world with the highest frequency in the tropics, subtropics, Mediterranean basin and Southeast Asia. This study aims to provide a better assessment on the spectrum of hemoglobinopathies in our context. Materials and Methods: This descriptive study was done at our tertiary care center, from November 2014 to October 2015. Hematological indices were derived from coulter counter, haemoglobin electrophoresis was carried out by cellulose acetate medium at alkaline PH. Sickling test, Hb H inclusions demonstration and Hb F estimation were performed. Parental screening was done wherever feasible. Results: Out of 350 cases referred from various out-patient departments of TUTH and different peripheral hospitals for suspected hemoglobinopathies, 97 cases (27.71%) had hemoglobinopathies. The most predominant hemoglobinopathy was thalassemia (57.73%) followed by sickle cell disorders (28.87%) and Hb D/Hb E hemoglobinopathies (13.40%). Most disorders were observed in the age group 21-30 years with many of the cases seen clustered in the families and a slight male preponderance. Terai region (71.13%) had a very high number. A significant high frequency of thalassemia (33.93%) and sickle cell disorders (75%) were seen in Tharu community. Conclusion: Hemoglobinopathies were seen widespread in Nepal. An extensive screening of the population is important to assess the prevalence of hemoglobinopathies, which will help in identification of carriers and take adequate therapeutic and preventive measures.

Using of photogenerated iodine for determination of 1,1-dimethylhydrazine in environmental objects

A photochemical method for determination of 1,1-dimethylhydrazine H2NN(CH3)2 (unsymmetrical dimethylhydrazine (UDMH)) based on titration of the analyte with photogenerated iodine obtained by irradiation of an auxiliary solution containing potassium iodide and a mixture of sensitizers (EOSIN Y:auramine:fluorescein taken in a molar ratio 1:1:1) in an acetate medium (pH 6) has been developed. With increasing acidity, a decrease in the rate of photogeneration is observed which is most likely attributed to disproportionation of the resultant titrant. Since the titrant (iodine) content is controlled by the voltammetric method, the photochemical titration of UDMH is accompanied by a decrease in the current strength in the circuit of the amperometric setup and stabilization indicates the completeness of the reaction. Measurements of the photogeneration time necessary to compensate for the loss of titrant in the cell upon further irradiation of the solution in the presence of atmospheric oxygen provide quantitative assessing of the UDMH content in environmental objects. Since the analyte interacts with the titrant in a molar ratio 1:2, we suggest the possibility of UDMH oxidation to NDMA (N-nitrosodimethylamine). A photochemical method of UDMH determination in solution is thus developed with the detection and determination limits (0.49 and 1.62) μg/ml, respectively. Unfortunately, the sensitivity of the proposed methodology does not allow determination of a toxic chemical contaminant at the MPC level which necessitates preconcentration of the mobile forms of UDMH by steam distillation in a 40 % sodium hydroxide solution. The developed methodology matches the validation parameters by the indices of linearity, ranking, correctness and thus can be recommended for determination of the UDMH content in any analytical laboratory. The photochemical method was tested in the analysis of soil samples taken from background and contaminated territories as well as natural water. A slight excess of the UDMH content has been found in the soil taken from the former location of the military unit.

Overexpression of the peroxin Pex34p suppresses impaired acetate utilization in yeast lacking the mitochondrial aspartate/glutamate carrier Agc1p

ABSTRACT PEX34, encoding a peroxisomal protein implicated in regulating peroxisome numbers, was identified as a high copy suppressor, capable of bypassing impaired acetate utilization of agc1∆ yeast. However, improved growth of agc1∆ yeast on acetate is not mediated through peroxisome proliferation. Instead, stress to the endoplasmic reticulum and mitochondria from PEX34 overexpression appears to contribute to enhanced acetate utilization of agc1∆ yeast. The citrate/2-oxoglutarate carrier Yhm2p is required for PEX34 stimulated growth of agc1∆ yeast on acetate medium, suggesting that the suppressor effect is mediated through increased activity of a redox shuttle involving mitochondrial citrate export. Metabolomic analysis also revealed redirection of acetyl-coenzyme A (CoA) from synthetic reactions for amino acids in PEX34 overexpressing yeast. We propose a model in which increased formation of products from the glyoxylate shunt, together with enhanced utilization of acetyl-CoA, promotes the activity of an alternative mitochondrial redox shuttle, partially substituting for loss of yeast AGC1.