Mycobacterium Tuberculosis H37Rv Strain Research Articles

The development and establishment of a heat inactivated preparation of Mycobacterium tuberculosis (H37Rv) as the first international standard for nucleic acid amplification techniques

A need to develop an inactivated Mycobacterium tuberculosis (Mtb) preparation, to be used as a DNA standard, as an important and urgent requirement for Tuberculosis (TB) diagnostics standardization was identified in 2018. A candidate material was generated using a heat inactivated culture of Mtb strain H37Rv. A lyophilised preparation was evaluated for its suitability as an International Standard for molecular detection of Mtb DNA in an international collaborative study. Together with the use of quantitative PCR assays and rapid diagnostic tests, this candidate standard was demonstrated to be fit-for-purpose. Based on the results from this collaborative study, it is proposed this lyophilised heat inactivated Mtb preparation (NIBSC code: 20/152) to be established by the World Health Organization Expert Committee on Biological Standardization, as the First WHO International Standard for Mycobacterium tuberculosis (H37Rv) for nucleic acid amplification techniques with an assigned unitage of 6.3 log10 or 2 × 106 International Units per vial.The intended uses of this IS are for calibration of secondary or in-house reference preparations used in the assays for the molecular detection of Mtb DNA. It may also be used for assay validation and monitoring the performance in terms of limit of detection of rapid diagnostic tests.

Design, synthesis and in vitro antitubercular evaluation of novel 7-methoxy pyrrolo[1,2-a]quinoline analogues as CYP 121 inhibitors

A novel series of pyrrolo[1,2-a]quinoline analogues (4a-n) was designed via a heterocyclic fusion approach for their antitubercular evaluation. The targeted compounds were synthesized by reacting 6-methoxy quinoline with different substituted phenacyl bromides, to get quinolinium ylide intermediates (2a-i), which have further undergone [3+2] cycloaddition with electron-deficient acetylenes to furnish novel 7-methoxy pyrrolo[1,2-a]quinoline derivatives (4a-n). All these newly synthesized intermediate products and final compounds have been characterized by spectroscopic techniques such as 1H NMR, 13C NMR, HRMS, and FT-IR. The intermediate ylides and final pyrrolo[1,2-a]quinoline analogues were evaluated for their antitubercular potential against the Mtb H37Rv strain (ATCC 27294). All the tested compounds exhibited antitubercular activity with the MIC99 in the range of 25–50 µM (10.4–25.7 µg/mL), compared to the standard drug Isoniazid (0.195 µM=0.026 µg/mL). An in silico molecular docking study revealed the strong binding affinity of target compounds with the enzyme Mtb CYP 121. The pharmacokinetic properties and toxicity predictions indicate overall drug-likeness for synthesized compounds. In this study, the compounds 4i, 4j, and 4k displayed considerable anti-TB activity against Mtb H37Rv with MIC99 values of 25 µM (10.43, 10.54, and 11.65 µg/mL respectively). CC50 of the test compounds were determined by cell viability assay using THP-1 macrophages. The compounds having methoxy and halogen substitution at the para position of the benzoyl fragment of designed molecules exhibited the best activity among the series.

Evaluation of Saraca asoca for its Anti‐Tubercular Potential via Molecular Docking and Molecular Dynamics Simulation Studies

AbstractNew treatment regimens against tuberculosis (TB), which is still a serious social problem, are urgently needed. Herein, the anti‐TB potential of methanolic extract of Saraca asoca (S. asoca) was evaluated against Mycobacterium tuberculosis (Mtb) H37Rv strain and ∼88 % inhibition was achieved. To explore the interaction of phytochemicals with the targets of mycobacteria, 13 phytochemicals of S. asoca were docked with 3 receptors of Mtb H37Rv viz VapC2, PPE41, and CarD. Among these phytochemicals, Epicatechol, Leucocynadin and Procynidin were found most effective against Mtb H37Rv VapC2 protein with docking energy of −9.92110, −9.77605 and −10.62900 kcal/mol, respectively. Isolariciresinol and Procynidin were effective against CarD (−8.18264 and −9.97703 kcal/mol, respectively) and PPE41 (docking energy −9.16713 and −11.59770 kcal/mol, respectively). ADMET properties suggested good bioavailability of the active compounds. Molecular dynamics simulation studies revealed that Epicatechol complex with VapC2 protein stabilized after 20 ns and can be further explored for its anti‐TB potential via cell‐based co‐culture assays and animal studies.

Isolation and Characterization of Anti-Mycobacterial Natural Products from a Petrosia sp. Marine Sponge.

Tuberculosis (TB) is a dreadful infectious disease and a leading cause of mortality and morbidity worldwide, second in 2020 only to severe acute respiratory syndrome 2 (SARS-Cov-2). With limited therapeutic options available and a rise in multidrug-resistant tuberculosis cases, it is critical to develop antibiotic drugs that display novel mechanisms of action. Bioactivity-guided fractionation employing an Alamar blue assay for Mycobacterium tuberculosis strain H37Rv led to the isolation of duryne (13) from a marine sponge Petrosia sp. sampled in the Solomon Islands. Additionally, five new strongylophorine meroditerpene analogues (1-5) along with six known strongylophorines (6-12) were isolated from the bioactive fraction and characterized using MS and NMR spectroscopy, although only 13 exhibited antitubercular activity.

Effect of Aloe Vera Extract and Second Line Anti-Tuberculosis Drugs on Mycobacterium Tuberculosis Strain-H37Rv

The present study was undertaken to examine the direct effect of second line anti-tuberculosis drugs Ethionamide (ETH), Para amino salicylic acid (PAS), Aloe vera on Mycobacterium tuberculosis (MTB) strain H37Rv ATCC No- 27294. It is found that Aloe vera does not interfere with single or in the combination of both ETH and PAS showing the bioenhancer activity. In vitro study of Aloe vera observed that the extract inhibited the growth of H37Rv strains. The present results will pave new avenues to find a new medicine that possesses Aloe vera alone or in combination with drugs to combat H37Rv strains controlling tuberculosis.

Antitüberküloz Triptantrin analoglarının elektronik ve topolojik özelliklerinin ve enoil-ACP redüktaz ile etkileşimlerinin in silico yöntemlerle incelenmesi

Objective:
 This study aimed to investigate the structure-antitubercular activity relationships of a series of tryptanthrin analogues and the binding mechanisms of these analogues with InhA, Mycobacterium tuberculosis enoyl-acyl carrier protein (enoyl-ACP) reductase.
 Methods:
 Structure-activity relationships were investigated by using Electronic-Topological Method combined with Neural Networks (ETM-NN). Binding energies and non-covalent interactions stabilizing the ligand-InhA complex were obtained from the results of molecular docking. To assess these interactions, frontier molecular orbital analysis of the ligand-InhA complexes were also analysed. 
 Results: 
 The results of the ETM-NN application to the series of compounds in view are pharmacophoric and anti-pharmacophoric molecular fragments, which are characteristic of the class of compounds demonstrating activity against Mycobacterium tuberculosis strain H37Rv. The statistical characteristics of five pharmacophores (Phi) and five anti-pharmacophores (APhi) entering the forecasting system, are 0.90 and 0.86, correspondingly. Analysis of the electron density distribution has shown that the more effective binding with receptor was observed for active compounds.
 Conclusions: 
 A system of prognosis for the anti-tubercular activity of Mycobacterium tuberculosis H37Rv was developed on the base of the pharmacophores found, docking results, and electronic structure calculations. This prognosis system allows for designing of new potent antitubercular drugs.
 Keywords: Tryptanthrin analogues, mycobacterium tuberculosis H37Rv, InhA electronic-topological method, molecular docking, density functional theory

Synthesis, Characterization, and Antitubercular Evaluation of Tetrahydrotetrazolo Quinazoline Derivatives

Background: Tuberculosis is a highly contagious disease that is one of the major causes of mortality worldwide and the leading infectious organism-related cause of death. Various tetrazole and quinazoline compounds have been successfully developed in the past for tuberculosis treatment. In this case, we planned to design the hybrid moieties by combining both tetrazole and quinazoline nuclei to create novel compounds with increased activity. Methods: 6, 6-dimethyl-5, 6, 7, 9–tetrahydrotetrazolo [5, 1-b] Quinazolin-8(4H) -one derivatives were synthesized, characterized by using spectral data. The antitubercular activity of the synthesized compounds was tested against the H37RV strain of Mycobacterium tuberculosis. In order to identify the interactions with the target protein Mtb Pks13 Thioesterase domain in complex with an inhibitor, docking analysis of the final compounds was performed (Protein data bank ID: 5V41). To verify their drug-like potential, the synthesized compounds were subjected to Pharmacokinetic prediction experiments. Zebrafish larvae had been used to test the teratogenicity of the synthesized compounds. Results: At 6.25 μg/mL, compounds F4 and F7 exhibited good efficacy against Mycobacterium tuberculosis strains. Docking studies aided in determining the most likely binding mode within the binding cavity of the concerned target protein. Conclusion: Compounds containing p-fluorophenyl and p-nitrophenyl groups as substituents were found to have excellent anti-tubercular activity.

A Machine Learning Language to Build a QSAR Model of Pyrazoline Derivative Inhibitors Targeting Mycobacterium tuberculosis Strain H37Rv

Background:Machine learning has become an essential tool for drug research to generate pertinent structural information to design drugs with higher biological activities. Quantitative structureactivity relationship (QSAR) is considered one technique. QSAR study involves two main steps: first is the generation of descriptors, and the second is building and validating the models.Aim:By using a Python program language for building the QSAR model of pyrazoline derivatives, the data were collected from diverse literature for the inhibition of Mycobacterium tuberculosis. Pyrazoline, a small molecule scaffold, could block the biosynthesis of mycolic acids, resulting in mycobacteria death and leading to anti-tubercular drug discovery.Methods:We have developed a new Python script that effectively uses CDK descriptor as the independent variable and anti-tubercular bioactivity as the dependent variable in building and validating the best QSAR model. The built QSAR model was further cross-validated by using the external test set compounds. Then, the three algorithms, viz. multiple linear regression, support vector machine, and partial least square classifiers, were used to differentiate and compare their r2 values.Results:Our generated QSAR model via an open-source python program predicted well with external test set compounds. The generated statistical model afforded the ordinary least squares (OLS) regression as R2 value of 0.514, F value of 5.083, the adjusted R2 value of 0.413, and std. error of 0.092. Moreover, the multiple linear regression showed the R2 value of 0.5143, reg.coef_ of, -0.07795 (PC1), 0.01619 (PC2), 0.03763 (PC3), 0.07849 (PC4), -0.09726 (PC5), and reg.intercept_ of 4.8324. The performance of the model was determined by the support vector machine classifier of sklearn, module and it provided a model score of 0.5901. Further, the model performance was supported by a partial least square regression, and it showed the R2 value of 0.5901. The model performance was validated, and the model predicted similar values when compared to that of the train set, and the plotted linear curve between the predicted and actual pMIC50 value showed all data to fall over the middle linear line.Conclusion:We have found that the model score obtained using this script via three diverse algorithms correlated well, and there was not much difference between them; the model may be useful in the design of a similar group of pyrazoline analogs as anti-tubercular agents.

Hydrazone-Tethered 5-(Pyridin-4-yl)-4H-1,2,4-triazole-3-thiol Hybrids: Synthesis, Characterisation, in silico ADME Studies, and in vitro Antimycobacterial Evaluation and Cytotoxicity.

Compounds containing arylpyrrole-, 1,2,4-triazole- and hydrazone structural frameworks have been widely studied and demonstrated to exhibit a wide range of pharmacological properties. Herein, an exploratory series of new 1,2,4-triazole derivatives designed by amalgamation of arylpyrrole and 1,2,4-triazole structural units via a hydrazone linkage is reported. The synthesised compounds were tested in vitro for their potential activity against Mycobacterium tuberculosis (MTB) H37 Rv strain. The most promising compound 13 - the derivative without the benzene ring appended to the pyrrole unit displayed acceptable activity (MIC90 =3.99 μM) against MTB H37 Rv, while other compounds from the series exhibited modest to weak antimycobacterial activity with MIC90 values in the range between 7.0 and >125 μM. Furthermore, in silico results, predicated using the SwissADME web tool, show that the prepared compounds display desirable ADME profile with parameters within acceptable range.

Glycerol based carbon sulfonic acid catalyzed synthesis, in silico studies and in vitro biological evaluation of isonicotinohydrazide derivatives as potent antimicrobial and anti-tubercular agents

The present pathway involves synthesis of isonicotinohydrazide derivatives using isoniazid and diversely substituted aldehydes in the presence of EtOH and catalytic amount of glycerol based carbon sulfonic acid catalyst. The developed pathway has so many merits like excellent yields (91–98%), short reaction time (4–10 min), easy reaction set up, no need of column chromatography, large substrate scope, easily recyclable and reusable catalyst. The synthesized compounds were screened for antimicrobial and anti-tubercular activity and it was observed that compounds possessed high biological potency against the Gram positive and Gram negative bacterial and fungal strains. Regarding anti-tubercular activity, compound 3m exhibited high % inhibition against Mycobacterium tuberculosis H37RV strain. Based on the outcome of in vitro studies, all the synthesized compounds were docked against E. coli (1KZN), C. albicans (1IYL), and M. tuberculosis H37Rv strain (2NSD). The synthesized derivatives were docked within the binding site of 1KZN, and 1IYL. However, with 2NSD, apart from 3h, all the derivatives displayed interaction within the binding cavity of the protein. All the crucial interactions with Asn46, Asp73, and Arg136 in 1KZN, His227, Leu451 in 1IYL, and Tyr158 in 2NSD were witnessed in the top-scored docked candidates. Molecular docking studies revealed the importance of the substitution at R position on isonicotinohydrazide scaffold. The nitrogen atoms of hydrazide moiety were involved in forming hydrogen bonding with the active site amino acids, and the substitution at the R position occupy the hydrophobic position in the binding pocket. Also, the functional groups present on the substituted R position were involved in forming hydrogen bonding with the crucial active site residues.

Synthesis of Novel 5‐Oxo‐1,2,4‐Oxadiazole Derivatives as Antitubercular Agents and Their Molecular Docking Study toward Enoyl Reductase (InhA) Enzyme

AbstractAn analogue of novel 3‐(1‐(4‐(benzoyl) benzyl)‐1H‐indol‐5‐yl)‐1,2,4‐oxadiazol‐5(4H)‐ones were synthesized in good yields (80–90 %), and its anti‐tubercular (anti‐TB) activity was investigated. All synthesized compounds (7 a–u) showed significant deterioration in the proliferation of the Mycobacterium tuberculosis H37Rv strain. A structure‐activity relationship (SAR) study was performed to identify compounds with mixed anti‐tubercular profiles. These compounds′ minimum inhibitory concentration (MIC) ranged between 0.78 and 25 μg/mL, comparable to standard drugs such as Ethambutol. Moreover, the derivative (7 l) (MIC of 0.78 μg/mL), amongst other 5‐oxo‐1,2,4‐oxadiazole, conferred anti‐TB activity more efficiently than Ethambutol (MIC of 1.56 μg/mL) when tested against all bacterial strains. Additionally, molecular docking studies were used against the mycobacterial enoyl reductase (InhA) enzyme to understand the binding modes of the potent compounds (7 l) and (7 m). Also evaluated were these molecules for in silico ADMET and drug similarity features. Thus, this study identified novel 5‐oxo‐1,2,4‐oxadiazoles as potential targets against tuberculosis. Further optimization of the molecule (7 l) could increase potency and aid in creating newer and better targets against M. tuberculosis.

Design, synthesis, molecular docking, and biological evaluation of coumarin-thymidine analogs as potent anti-TB agents.

With the intent to discover new antituberculosis (TB) compounds, coumarin-thymidine analogs were synthesized using second-order nucleophilic substitution reactions of bromomethyl coumarin with thymidine. The newly synthesized coumarin-thymidine conjugates (1a-l) were characterized using IR, NMR, GC-MS, and CHN elemental analysis. The novel conjugates were found to exhibit potent anti-TB activity against the Mycobacterium tuberculosis H37 Rv strain, with minimum inhibitory concentrations (MIC) of the active compounds ranging between 0.012 and 0.482 µM. Compound 1k was established as the most active candidate with a MIC of 0.012 µM. The toxicity study on HEK cells confirmed the nontoxic nature of compounds 1e, 1h, 1i, 1j, and 1k. Also, the most active compounds (1k, 1j, and 1e) were stable in the pH range from 2.5 to 10, indicating compatibility with the biophysical environment. Based on the pKa studies, compounds 1k, 1j, and 1e are capable of crossing lipid-membrane barriers and acting on target cells. Molecular docking studies on the M. tuberculosis β-oxidation trifunctional enzyme (PDB ID: 7O4V) were conducted to investigate the mechanisms of anti-TB activity. All compounds showed excellent hydrogen binding interactions and exceptional docking scores against M. tuberculosis, which was in accordance with the results. Compounds 1a-l possessed excellent affinity to proteins, with binding energies ranging from -7.4 to -8.7 kcal/mol.

A nano-organo catalyst mediated approach towards the green synthesis of 3-methyl-4-(phenyl)methylene-isoxazole-5(4H)-one derivatives and biological evaluation of the derivatives as a potent anti-fungal and anti-tubercular agent

An efficient and green protocol for the one-pot synthesis of 3-methyl-4-(phenyl)methylene-isoxazole-5(4H)-one derivatives catalyzed by a novel acid functionalized Fe3O4 nanoparticles (NPs) is reported herein. The catalyst was synthesized and characterized by various analytical techniques. Ultrasound energy has been efficiently exploited for the preparation of the catalyst as well as the synthesis of a series of the aforesaid compounds. The salient features of this protocol include mild reaction condition, easy catalyst recovery, shorter reaction time and use of environmental-friendly solvents. In addition, preliminary in-vitro antifungal and antimycobacterial screening of the synthesized compounds were conducted against three pathogenic fungi viz., Aspergillus fumigatus, Aspergillus flavus, Fusarium oxysporum and M. tuberculosis H37Rv respectively. Interestingly, 3-chloromethyl-4-(phenyl) methylene-isoxazole-5(4H)-one series exhibited over 50% growth inhibition against the mycelial growth of the fungi Fusarium oxysporum at 100 μg/mL. Whereas 4-(1H-indol-3-ylmethylene)-3-methyl-4H-isoxazol-5-one and 3-chloromethyl-4-(2,4,6-trimethyl-benzylidene)-4H-isoxazol-5-one displayed antimycobacterial activity against Mycobacterium tuberculosis H37Rv strain equipotent to the standard drug, ethambutol (MIC 1.56 μg/mL).

Mycobacterium tuberculosis Cell Wall Antigens Induce the Formation of Immune Complexes and the Development of Vasculitis in an Experimental Murine Model.

Tuberculosis (TB) of the central nervous system (CNS) presents high mortality due to brain damage and inflammation events. The formation and deposition of immune complexes (ICs) in the brain microvasculature during Mycobacterium tuberculosis (Mtb) infection are crucial for its pathobiology. The relevance of ICs to Mtb antigens in the pathogenesis of CNS-TB has been poorly explored. Here, we aimed to establish a murine experimental model of ICs-mediated brain vasculitis induced by cell wall antigens of Mtb. We administered a cell wall extract of the prototype pathogenic Mtb strain H37Rv to male BALB/c mice by subcutaneous and intravenous routes. Serum concentration and deposition of ICs onto blood vessels were determined by polyethylene glycol precipitation, ELISA, and immunofluorescence. Histopathological changes in the brain, lung, spleen, liver, and kidney were evaluated by hematoxylin and eosin staining. Our results evidenced that vasculitis developed in the studied tissues. High serum levels of ICs and vascular deposition were evident in the brain, lung, and kidneys early after the last cell wall antigen administration. Cell wall Mtb antigens induce strong type III hypersensitivity reactions and the development of systemic vasculitis with brain vascular changes and meningitis, supporting a role for ICs in the pathogenesis of TB.

Mycobacterium tuberculosis Rv0494 Protein Contributes to Mycobacterial Persistence.

Fatty acid metabolism plays an important role in the survival and pathogenesis of Mycobacterium tuberculosis. During dormancy, lipids are considered to be the main source of energy. A previous study found that Rv0494 is a starvation-inducible, lipid-responsive transcriptional regulator. However, the role of Rv0494 in bacterial persister survival has not been studied. We constructed a Rv0494 deletion mutant strain of Mycobacterium tuberculosis H37Rv and evaluated the susceptibility of the mutant strain to antibiotics using a persistence test. We found that mutations in Rv0494 lead to survival defects of persisters, which reflected in increased sensitivity to isoniazid. We conclude that Rv0494 is important for persister survival and may serve as a good target for developing new antibiotics that kill persister bacteria for improved treatment of persistent bacterial infections.

Design, Synthesis, Anti-tubercular and Docking Studies of Novel 2-Furanyl-3-substituted Quinazolin-4-one Derivatives

In this work, the synthesis, characterization and the anti-tubercular activity of novel 2-furanyl-3- substituted quinazolin-4-one derivatives and also predicted their affinity against Mycobacterium tuberculosis enoyl acyl carrier protein reductase were carried out. The targeted compounds were synthesized by the condensation of 2-(furan-2-yl)-4(3H)-1-benzoxazine-4-one with different primary amines. After structural elucidation using spectral data, the compounds were screened for anti-tubercular activity against Mycobacterium tuberculosis H37RV strain. The binding affinity against enoyl acyl carrier protein reductase was predicted using MOE and FITTED docking tools. The synthesized compounds showed a promising anti-tubercular activity in the range from 12.5 to 100 μg/mL. According to MOE docking, the common amino acids in the active site of InhA were found to form hydrogen bonding and hydrophobic interactions with the synthesized quinazolinones. Docking simulations also showed that an aromatic side chain capable of forming hydrogen bond interactions can increase affinity of 2-furanyl quinazolinones to enoyl acyl carrier protein reductase.

Design, Synthesis and Anti-tubercular Evaluation of Some Novel Chroman-Hydrazone Derivatives

The molecular docking, synthesis, spectral characterization and anti-tubercular evaluation of 10 novel N’-substituted-6-hydroxy-2,5,7,8-tetramethylchroman-2-carbohydrazide derivatives (SM1-SM10) were reported. The structures of the synthesized derivatives were affirmed by spectroscopic studies such as FTIR, 1H NMR, 13C NMR and high resolution-mass spectrometry. Predicted ADME and toxicity investigations were accomplished to presume the pharmacokinetic parameters of the compounds. The synthesized compounds were evaluated for in vitro anti-tubercular activity against Mycobacterium tuberculosis H37Rv strain using Microplate Alamar Blue Assay (MABA) taking isoniazid, rifampicin, ethambutol, amikacin, streptomycin and levofloxacin as positive drug standards. Compound SM8 has shown the significant anti-tubercular activity among all the titled compounds. The results indicated that chroman-hydrazone skeleton could serve as a lead for the development of novel anti-tubercular drugs.

Isoquinoline Containing Azo Schiff Derivatives as Potential Antitubercular Agents: Synthesis, Characterization, Molecular Docking, PASS Prediction and ADME Studies

A series of isoquinoline containing novel azo Schiff base derivatives (3a-l) were synthesized and characterized by FT-IR, NMR (1H NMR & 13C NMR) and mass spectral analysis. The synthesized title compounds were evaluated for in vitro antitubercular activity against Mycobacterium tuberculosis (MTB) H37Rv strain by microplate alamar blue assay (MABA) method. Among the synthesized series of compounds, the compounds 3a, 3b, 3c and 3d were emerged as excellent antitubercular agents. Compound 3b showed the lowest MIC value of 1.6 μg/mL with a potency equivalent to the standards, isoniazid and ethambutol. Compounds 3a & 3c showed MIC value of 3.125 μg/mL, which is equivalent to the activity of a reference standard pyrazinamide. Compound 3d showed significant activity with MIC of 6.25 μg/mL and other compounds showed good to moderate activity ranging from 12.5 to 50 μg/mL. The four potent components were further tested for in vitro cytotoxicity using MTT assay against MCF-7 and HeLa cell lines to check the selectivity index. Among the tested series, compound 3b possessed the highest cytotoxicity against both MCF-7 (IC50, 7.09 ± 0.41) and HeLa (IC50, 9.04 ± 0.34) cell lines. Additionally, in silico molecular docking was performed to study its binding interaction with Mycobacterium tuberculosis enoyl reductase (InhA) and drug-like features were studied using Swiss ADME tool. PASS analysis of all the compounds showed greater Pa than Pi value for the antituberculosis activity. The results suggested that the synthesized isoquinoline containing azo Schiff base derivatives becomes promising for developing new drugs to treat tuberculosis.

Inflammation induced by excessive expression of CD4 T-cell lymphocytes & proinflammatory cytokines results in bacterial dissemination in Mycobacterium tuberculosis-infected guinea pig model.

As CD4+ and CD8+ T lymphocyte numbers decline, the conventional, localized forms of tuberculosis shift to the atypical, disseminated forms. Variations in lymphocyte and immune cell expression levels affect how tuberculosis manifests in disseminated forms. Understanding the relationship between lymphocyte counts (CD4+ and CD8+) and pro-inflammatory cytokines such as tumour necrosis factor-alpha, interleukin-12 and interferon, we may therefore be able to shed light on how infections spread and suggest potential biomarkers for these immune factors. In this study, 15 guinea pigs were infected with Mycobacterium tuberculosis (M.tb) H37Rv strain and grouped into three groups of five each for further investigation. Serum samples and bronchoalveolar lavage (BAL) fluid were examined for the expression of pro-inflammatory cytokines and T-cell subsets in guinea pigs infected with pulmonary tuberculosis and disseminated tuberculosis. We found that M.tb escapes macrophages due to pro-inflammatory cytokine dysregulation. Despite the protective immunity created by T-cells and cytokines, M.tb bacilli may spread to other organs due to inflammation induced by these immune components. A high number of T-cells and stimulated cytokine production are involved in triggering inflammation after necrotic tissue develops and tuberculosis spreads. Our findings imply that increased bacilli in the spleen at the eighth week of infection may be caused by the overexpression of CD4+ T-cell lymphocyte subsets and cytokines that generated inflammation during the fourth week of infection. This is a pilot study with a small sample size and less assertive inference. Larger studies would be helpful to validate the results of the present investigation.

A convenient synthesis, characterization and biological evaluation of novel schiff base heterocycles as potential antimicrobial, antitubercular agents and their structural activity relationship

A series of (E)-1-methyl-3-((substituted phenylimino)methyl)quinolin-2(1H)-one schiff bases (3a-j) bearing quinoline moiety synthesized successfully in ethanol by condensation of starting material 1-methyl-2-oxo-1,2-dihydroquinoline-3-carbaldehyde (1) with various substituted anilines (2a-j). The structure of the newly synthesized compounds was confirmed by proton (1H) and carbon (13C) nuclear magnetic resonance spectroscopy, Fourier transformation infrared (FT-IR), Mass spectroscopic study and elemental analysis. The in-vitro antimicrobial activity of the synthesized compounds was undertaken by agar well diffusion method against gram positive bacteria (Bacillus licheniformis and Bacillus cereus) gram negative bacteria (Escherichia coli and Acetobactor sp.) and antifungal activity against (Aspergillus Flavus and Pichnanomala). Further the compounds which shows good activity (3b, 3c, 3d, 3f, 3g and 3j) are screened for in-vitro antitubercular activity by Micro-plate alamar blue assay (MABA) method against mycobacterium tuberculosis H37Rv strain provided important information about activity against these strains. The structure activities of the synthesized compounds were also discussed. Compounds 3a, 3c, 3d, 3f and 3g show good argument with the different substituent attached to the phenyl ring.