Jorge Castro-Garza

Synthesis and in vitro antiprotozoal activity of 5-nitrothiophene-2-carboxaldehyde thiosemicarbazone derivatives

Several thiosemicarbazone derivatives of 5-nitrothiophene-2-carboxaldehyde were prepared by the simple process in which N(4)-thiosemicarbazone moiety was replaced by aliphatic, arylic and cyclic amine. Among these thiosemicarbazones compound 11 showed significant antiamoebic activity whereas compound 3 was more active antitrichomonal than the reference drug.

PEHPS medium: An alternative for axenic cultivation of Entamoeba histolytica and E. invadens

Knowledge of Entamoeba histolytica biology in the last 17 years has been acquired largely as a consequence of this parasites axenic cultivation in TPS-1 or TYI-S-33 media. Unfortunately, there are often low yields in these media, due to variability of their main components, Panmede and yeast extract. We describe a medium, PEHPS, of which the main components are extracts of ox liver, and ox and swine pancreas (EHP). 5 strains of E. histolytica and 2 of E. invadens were quickly and easily adapted to PEHPS and serially cultivated for 3 years. Yields progressively rose initially, and then became stable. Depending on the strain, average yields in the last 6 months of this study were 1.3 to 3.1 x 10(5) amoebae/ml for E. histolytica and 5.5 to 5.7 x 10(5) for E. invadens. All the 18 EHP batches tested supported vigorous amoebal growth. PEHPS had 2 additional advantages: (a) it was stable at 4 degrees C or 25 degrees C for 9 months, and at -10 degrees C for at least 2 years, and (b) it supported amoebal growth with inocula as low as one trophozoite/ml. PEHPS avoids the variability shown by TPS-1 and TYI-S-33, and could therefore be a good alternative for axenic amoebal cultivation.

Synthesis, characterization and antiamoebic activity of benzimidazole derivatives and their vanadium and molybdenum complexes.

Reaction of [MoO(2)(acac)(2)] (where, acac=acetyl acetone) and KVO(3) with 2-(salicylidieneimine) benzimidazole lead to form new complexes [MoO(2)(sal-BMZ)(2)] and K [VO(2)(sal-BMZ)(2)] [where, sal-BMZ=2-(salicylidieneimine) benzimidazole], which showed the monobasic bidentate nature of the ligand in which the phenolic oxygen and the imine nitrogen of the ligand are coordinated to the metal ion. These complexes were characterized along with nine other complexes of oxoperoxovanadium (V), molybdenum (Vl) and tungsten (Vl) with benzimidazole derivatives and screened in vitro by micro dilution technique for their amoebicidal activity with a view to search for a more effective agent against Entamoeba histolytica suggests that compound 2 and 3 might be endowed with important antiamoebic properties since they showed IC(50 )values in a microM range.

Phospholipase Region of Mycobacterium tuberculosis Is a Preferential Locus for IS6110 Transposition

ABSTRACT Enzymes with phospholipase C activity in Mycobacterium tuberculosis have been recently described. The three genes encoding these proteins, plcA, plcB, andplcC, are located at position 2351 of the genomic map ofM. tuberculosis H37Rv and are arranged in tandem. We have previously described the presence of variations in the restriction fragment length polymorphism patterns of the plcA andplcB genes in M. tuberculosis clinical isolates. In the present work we investigated the origin of this polymorphism by sequence analysis of the phospholipase-encoding regions of 11 polymorphic M. tuberculosisclinical isolates. To do so, a long-PCR assay was used to amplify a 5,131-bp fragment that contains the plcA andplcB genes and part of the plcC gene. In the M. tuberculosis strains studied the production of an amplicon ∼1,400 bp larger than anticipated was observed. Sequence analysis of the PCR products indicated the presence of a foreign sequence that corresponded to an IS6110 element. We observed insertion elements in the plcA,plcB, and plcC genes. One site inplcB had the highest incidence of transposition (5 out of 11 strains). In two strains the insertion element was found inplcA in the same nucleotide position. In all the cases, IS6110 was transposed in the same direction. The high level of transposition in the phospholipase region can lead to the excision of fragments of genomic DNA by recombination of neighboring IS6110 elements, as demonstrated by finding the deletion, in two strains, of a 2,837-bp fragment that includedplcA and most of plcB. This can explain the negative results obtained by some authors when detecting themtp40 sequence (plcA) by PCR. Given the high polymorphism in this region, the use of the mtp40sequence as a genetic marker for M. tuberculosis sensu stricto is very restricted.

Antimycobacterial Activity of Juglans regia, Juglans mollis, Carya illinoensis and Bocconia frutescens

Mycobacterium tuberculosis is a serious worldwide health threat, killing almost 2 million people per year. Alternative antimycobacterial drugs are urgently needed; studies have shown that medicinal plants traditionally used to treat respiratory diseases are a potential source of compounds to treat tuberculosis. This paper studied the antimycobacterial activity of 28 extracts from four different plant species that have been used in traditional Mexican medicine to treat tuberculosis. Bark and leaf crude extracts of Juglans regia L., Juglans mollis Engelm., Carya illinoensis (Wangenh) K. Koch and Bocconia frutescens showed in vitro anti‐M. tuberculosis activity. Hexane bark extracts from C. illinoensis, J. mollis and J. regia were the most active with a minimal inhibitory concentration (MIC) of 31, 50 and 100 µg/mL, respectively. Ethanol bark extracts from C. illinoensis and J. mollis showed activity at 100 and 125 µg/mL, respectively. Leaf extracts had the lowest activity. Methanol and hexane leaves extracts from B. frutescens had a MIC of 125 µg/mL. None of the aqueous extracts showed antimycobacterial activity. Copyright

Identification ofEntamoeba histolytica intracellular phospholipase A and lysophospholipase L1 activities

Entamoeba histolytica phospholipase A and lysophospholipase activities from a vesicular subcellular fraction (P30) were analyzed. The products, obtained using specific substrates labeled with14C or3H, indicated the presence of phospholipase A1 and A2 as well as lysophospholipase L1 activities. The enzymes detected could participate in phospholipid metabolism and the alkaline phospholipase A2 may contribute toE. histolytica cytopathogenicity.

Intracellular activity of tedizolid phosphate and ACH-702 versus Mycobacterium tuberculosis infected macrophages.

BackgroundDue to the emergency of multidrug-resistant strains of Mycobacterium tuberculosis, is necessary the evaluation of new compounds.FindingsTedizolid, a novel oxazolidinone, and ACH-702, a new isothiazoloquinolone, were tested against M. tuberculosis infected THP-1 macrophages. These two compounds significantly decreased the number of intracellular mycobacteria at 0.25X, 1X, 4X and 16X the MIC value. The drugs were tested either in nanoparticules or in free solution.ConclusionTedizolid and ACH-702 have a good intracellular killing activity comparable to that of rifampin or moxifloxacin.

Activity of novel oxazolidinones against Nocardia brasiliensis growing within THP-1 macrophages

BACKGROUND Nocardia are organisms that can escape the effects of both immune response and antimicrobial agents, due to their potential capacity to grow intracellularly. In previous studies, we found that experimental oxazolidinones, DA-7157 and DA-7218, are active both in vitro and in vivo. OBJECTIVES In this study, we compare the ability of linezolid, DA-7157 and DA-7218 to inhibit intracellular growth of Nocardia brasiliensis within the human monocyte cell line THP-1. METHODS AND RESULTS The addition of oxazolidinones to the infected macrophage monolayer at concentrations 0.25x, 1x, 4x and 16x the MIC for N. brasiliensis resulted in an inhibitory effect on bacterial growth as follows DA-7157 > or = DA-7218 > linezolid. CONCLUSIONS The excellent intracellular antimicrobial activity detected suggests that these compounds could be effective in the treatment of actinomycetoma. However, more studies are needed both in vitro and in vivo, including clinical trials, to confirm this issue.

In Vitro Susceptibility of Mycobacterium tuberculosis Clinical Isolates to Garenoxacin and DA-7867

ABSTRACT The in vitro activities of DA-7867, a novel oxazolidinone, and garenoxacin (BMS-284756) were compared to those of linezolid in 67 susceptible and drug-resistant clinical isolates of Mycobacterium tuberculosis. DA-7867 was the most active drug with an MIC90 of 0.125 μg/ml, compared to the MIC90s of 4 μg/ml of garenoxacin and 2 μg/ml of linezolid.

Auxotrophy to lipoproteins of Entamoeba histolytica cultivated under axenic conditions

Entamoeba histolytica grows in media without serum but with a mixture of aminoacids, vitamins, lipoproteins, free cholesterol, phospholipids and fatty acids called PACSR. The ability of lipoproteins and free lipids to support growth of three E. histolytica strains (HK9, HMI:IMSS and HM3:IMSS) was analysed. Tubes containing 5 ml culture medium, amino acids, vitamins and either 120–1,200 μg lipoproteins/ml or 0.017–0.10 mg free lipids/ml (predissolved in absolute ethanol) were inoculated with 1 × 104 trophozoites/ml and incubated at 37 °C for 72 h. Amoebae died within 12 h in the presence of any free lipid combination, while those having 240–480 mg lipoproteins/ml reached densities similar to or higher than those of controls (depending on strain). The addition of ethanol (0.1%) to the media produced stable lipid solutions and did not show significant adverse effects. Accordingly, E. histolytica is auxotrophic to lipoproteins and unable to use free cholesterol, phospholipids or fatty acids.