Mycobacterium Research Papers - Academia.edu (original) (raw)

One limiting factor in studies of tuberculosis and leprosy is the difficulty of genetic analysis and manipulation of mycobacteria. Two approaches were adopted for the construction of vectors, based on different Escherichia coli plasmids... more

One limiting factor in studies of tuberculosis and leprosy is the difficulty of genetic analysis and manipulation of mycobacteria. Two approaches were adopted for the construction of vectors, based on different Escherichia coli plasmids and using Mycobacterium smegmatis as the host. In both cases we found that the original E. coli plasmid is capable of being replicated in M. smegmatis, yielding chloramphenicol-resistant colonies. One such plasmid has been recovered from a M. smegmatis transformant and used to re-transform both M. smegmatis and E. coli to chloramphenicol resistance. This plasmid is indistinguishable from the original plasmid by restriction analysis, and can be used as a shuttle vector for the genetic manipulation of mycobacterial species.

Patients with end-stage renal disease are at high risk of mycobacterial infection. To analyze the difficulties in reaching an accurate diagnosis of tuberculosis in dialysis patients. We conducted a retrospective follow-up of patients who... more

Patients with end-stage renal disease are at high risk of mycobacterial infection. To analyze the difficulties in reaching an accurate diagnosis of tuberculosis in dialysis patients. We conducted a retrospective follow-up of patients who attended our peritoneal and hemodialysis units during the 10 year period 1995-2005. Our dialysis unit diagnosed 10 cases of tuberculosis caused by Mycobacterium tuberculosis and 9 cases of Mycobacterium other than tuberculosis. In the former group, five patients had Mycobacterium in the sputum, which was diagnosed by intraabdominal mass biopsy in one, culture of the gastric juices in one, and pleural fluid culture or pleural biopsy in three. One of these patients was suffering from pleural TB as well as Potts disease. Of the patients with Mycobacterium other than tuberculosis, five were diagnosed by sputum cultures, three by urine cultures and one in peritoneal fluid. Differences in treatment and outcome were also reviewed. The diagnosis of TB in di...

Five new copper(II) complexes of the type [Cu(NO)(NN)(ClO4)2], in which NO=4-fluorophenoxyacetic acid hydrazide (4-FH) or 4-nitrobenzoic hydrazide (4-NH) and NN=1,10-phenanthroline (phen), 4-4'-dimethoxy-2-2'-bipyridine (dmb) or... more

Five new copper(II) complexes of the type [Cu(NO)(NN)(ClO4)2], in which NO=4-fluorophenoxyacetic acid hydrazide (4-FH) or 4-nitrobenzoic hydrazide (4-NH) and NN=1,10-phenanthroline (phen), 4-4'-dimethoxy-2-2'-bipyridine (dmb) or 2,2-bipyridine (bipy) were synthesized and characterized using various spectroscopic methods. The X-ray structural analysis of one representative compound indicates that the geometry around the copper ion is distorted octahedron, in which the ion is coordinated to hydrazide via the terminal nitrogen and the carbonyl oxygen, and to heterocyclic bases via their two nitrogen atoms. Two perchlorate anions occupy the apical positions, completing the coordination sphere. The cytotoxic activity of compounds was investigated in three tumor cell lines (K562, MDA-MB-231 and MCF-7). Concerning K562 cell line, the complexes with 1,10-phenanthroline exhibit high cytotoxic activity and are more active than carboplatin, free ligands and [Cu(phen)2](2+). Considering...

Nucleic acid sample preparation has been an especially challenging barrier to point-of-care nucleic acid amplification tests in low-resource settings. Here we provide a head-to-head comparison of methods for lysis of, and nucleic acid... more

Nucleic acid sample preparation has been an especially challenging barrier to point-of-care nucleic acid amplification tests in low-resource settings. Here we provide a head-to-head comparison of methods for lysis of, and nucleic acid release from, several pathogenic bacteria and viruses-methods that are adaptable to point-of-care usage in low-resource settings. Digestion with achromopeptidase, a mixture of proteases and peptidoglycan-specific hydrolases, followed by thermal deactivation in a boiling water bath, effectively released amplifiable nucleic acid from Staphylococcus aureus, Bordetella pertussis, respiratory syncytial virus, and influenza virus. Achromopeptidase was functional after dehydration and reconstitution, even after eleven months of dry storage without refrigeration. Mechanical lysis methods proved to be effective against a hard-to-lyse Mycobacterium species, and a miniature bead-mill, the AudioLyse, is shown to be capable of releasing amplifiable DNA and RNA from...

The ability to utilize sterols as a sole source of carbon was studied in 80 strains and consortia of hydrocarbon-oxidizing bacteria. One of the strains, which efficiently transformed both individual sterols and their mixtures, was... more

The ability to utilize sterols as a sole source of carbon was studied in 80 strains and consortia of hydrocarbon-oxidizing bacteria. One of the strains, which efficiently transformed both individual sterols and their mixtures, was identified as Mycobacterium neoaurum, based on the analysis of the sequence of the 16S rRNA gene.

Tuberculosis, caused by Mycobacterium tuberculosis, and leprosy, caused by M. leprae, are diseases known since antiquity. In developing countries, tuberculosis is still the leading cause of mortality due to an infectious disease.... more

Tuberculosis, caused by Mycobacterium tuberculosis, and leprosy, caused by M. leprae, are diseases known since antiquity. In developing countries, tuberculosis is still the leading cause of mortality due to an infectious disease. Taxonomically, mycobacteria belong to the genus Mycobacterium, which is the single genus within the family of Mycobacteriaceae, in the order Actinomycetales. Actinomycetales include diverse micro-organisms, but mycobacteria and allied taxa are easily distinguished on the basis of the ability to synthesise mycolic acids. Mycobacterial species are traditionally differentiated on the basis of phenotypic characteristics, and the authors provide an updated list of the biochemical tests currently employed and the culture properties that help to discriminate among various species of mycobacteria. However, as the phenotypic characteristics do not allow precise identification of all species, recent molecular taxonomical approaches for mycobacterial classification an...

A system for the tetracycline-inducible regulation of gene expression in mycobacteria has been developed. We have sub-cloned the tetRO region from the Corynebacterium glutamicum TetZ locus into a mycobacterial shuttle plasmid, making... more

A system for the tetracycline-inducible regulation of gene expression in mycobacteria has been developed. We have sub-cloned the tetRO region from the Corynebacterium glutamicum TetZ locus into a mycobacterial shuttle plasmid, making expression of genes cloned downstream of tetRO responsive to tetracycline. Using the luxAB-encoded luciferase from Vibrio harveyi as a reporter (pMind-Lx), we observed a 40-fold increase in light output from Mycobacterium smegmatis cultures 2 h after adding 20 ng ml−1 of tetracycline. Similarly, exposure to the drug resulted in up to 20-fold increase in relative light units from M.bovis BCG carrying the reporter construct, and a 10-fold increase for M.tuberculosis. Tetracycline induction was demonstrated in log and stationary phase cultures. To evaluate whether this system is amenable to use in vivo, J774 macrophages were infected with M.bovis BCG[pMind-Lx], treated with amikacin to kill extracellular bacteria, and then incubated with tetracycline. A 10-fold increase in light output was measured after 24 h, indicating that intracellular bacteria are accessible and responsive to exogenously added tetracycline. To test the use of the tetracycline-inducible system for conditional gene silencing, mycobacteria were transformed with a pMind construct with tetRO driving expression of antisense RNA for the ftsZ gene. Bacterial cells containing the antisense construct formed filaments after 24 h exposure to tetracycline. These results demonstrate the potential of this tetracycline-regulated system for the manipulation of mycobacterial gene expression inside and outside cells.

In-room air cleaners (ACs) and upper-room air ultraviolet germicidal irradiation (UVGI) are engineering control technologies that can help reduce the concentrations of airborne bacteria and fungal spores in the indoor environment. This... more

In-room air cleaners (ACs) and upper-room air ultraviolet germicidal irradiation (UVGI) are engineering control technologies that can help reduce the concentrations of airborne bacteria and fungal spores in the indoor environment. This study investigated six different types of ACs and quantified their ability to remove and/or inactivate airborne bacteria and fungal spores.Four of the air cleaners incorporatedUVlamp(s) into their flow

A study of the applicability of a colorimetric biuret procedure for protein determination to a variety of biological preparation has revealed that the practice of using this procedure is undesirable because markedly apparent high values... more

A study of the applicability of a colorimetric biuret procedure for protein determination to a variety of biological preparation has revealed that the practice of using this procedure is undesirable because markedly apparent high values are obtained in this way. In some cases, this interference was mainly due to lipids. Use of suitable controls to account for the interfering opalescence in biuret color measurements considerably improved the method. Conditions affecting the reliability of the procedure are also described. For crude extracts the colorimetric phenol method was found to be more reliable. However, a prior separation of protein by TCA is often advantageous not alone for Kjeldahl analysis but also for colorimetric estimations. The actual chromogenicity of the protein mixtures of different biological extracts studied was found to be comparable to that of the commonly employed standard protein, bovine serum albumin.

Tuberculosis continues to be an important disease both in humans and animals. It causes morbidity, mortality and economic loss worldwide. The occurrence of Mycobacterium bovis disease in humans, domesticated and wild animals confirms the... more

Tuberculosis continues to be an important disease both in humans and animals. It causes morbidity, mortality and economic loss worldwide. The occurrence of Mycobacterium bovis disease in humans, domesticated and wild animals confirms the relevance of this zoonosis. M. bovis in humans continues to be reported in industrialised countries and in immigrants from regions of the world where tuberculosis in cattle is endemic. The real incidence of M. bovis in humans in developing countries continues to be roughly under-estimated due to the scarcity of appropriate laboratory facilities to isolate and to differentiate M. bovis strains. In Latin America, less than 1% of tuberculosis cases are reported as being due to M. bovis. However, the economic relevance that meat and dairy industries play in these countries stimulates the promotion of bovine tuberculosis eradication programmes. Human-to-human airborne transmission of M. bovis does occur and it may be important where human immunodeficiency virus (HIV) infection in humans is prevalent, M. bovis infection in cattle is enzootic and pasteurisation of dairy products is not routinely practised. Eradication of M. bovis in cattle and pasteurisation of dairy products are the cornerstones of prevention of human disease. Measures should be developed to identify and control M. bovis infection in wild animals as these may be important reservoirs of infection for domesticated food-producing animals. There is a need for medical and veterinary professionals to cooperate on disease outbreaks. The information presented herein strongly supports the ‘One World/One Health/One Medicine’ concept.

A study to determine the secretion of Mycobacterium spp. in milk from indigenous cattle was carried out in pastoral cattle reared in the Southern Highlands to Tanzania. The study was aimed at elucidating the dangers associated with... more

A study to determine the secretion of Mycobacterium spp. in milk from indigenous cattle was carried out in pastoral cattle reared in the Southern Highlands to Tanzania. The study was aimed at elucidating the dangers associated with milk-borne zoonoses in a society where milk is normally consumed raw. Out of 805 milk samples, 31 (3.9%) were positive for mycobacteria. There was a preponderance of atypical mycobacteria (87%) whereas only two isolates (6.5%) were confirmed as M. bovis. Atypical mycobacteria included: M. terrae (n = 7), M. fortuitum (n = 2), M. flavescens (n = 13), M. gordonae (n = 1) and M. smegmatis (n = 4). Although the number of M. bovis positive samples was low, the habit of pooling milk may still pose great public health dangers to milk consumers in this part of the world. Moreover, isolation of atypical mycobacteria should also be considered to be a danger to human health in countries such as Tanzania, where the number of people with lowered immunity due to HIV in...