Summary
Bovine tuberculosis is caused by Mycobacterium bovis, a mycobacterium highly similar to M. tuberculosis that belongs to the M. tuberculosis complex. The main host of M. bovis is cattle but it ...also affects many other mammalians including humans. Tuberculosis in humans caused by either M. bovis or M. tuberculosis is clinically hard to distinguish. During 2004–2005, samples from 448 patients with diagnosis of TB were collected from different regions of Argentina. The PRA technique identified 400 isolates with representative patterns of mycobacterium. The predominant ones were the M. tuberculosis complex, the M. avium–M. intracellulare complex and M. gordonae. Samples with M. tuberculosis complex PRA restriction profiles were analyzed with a multiplex PCR to differentiate between M. tuberculosis and M. bovis. Multiplex PCR identified nine M. bovis. The results allowed the possibility to establish that 2% of pulmonary tuberculosis was due to M. bovis. Isolates of M. bovis from humans were examined using spoligotyping. These isolates presented five different spoligotypes. The main spoligotype was also the most frequently one found in cattle. The remaining human spoligotypes (grouped in clusters) are occasionally found in cattle. Variable number tandem repeat (VNTR) analysis identified five different patterns. By combining the results of spoligotyping and VNTR analysis, we were able to differentiate seven M. bovis isolates. The remaining two M. bovis samples showed the same spoligotype and VNTR profile and belonged to household contacts. An MDR‐M. bovis was isolated from the samples of these household contacts. The identification of two epidemiologically linked cases of human M. bovis infection suggests person‐to‐person transmission of an MDR‐M. bovis.
Johne's disease or paratuberculosis is widespread in almost all countries and remains difficult to eradicate. Nowadays, diagnosis of
Mycobacterium avium subsp.
paratuberculosis (MPTB) infection is ...one of the main concerns. In this work, we evaluated the expression, biochemical properties and antigenicity of the Apa antigen, encoded by the gene annotated as MAP1569, in the MPTB genome. We confirmed its expression in MPTB and its glycosylation by the ConA binding assay. Although the MPTB-Apa is not an immunodominant antigen, MPTB-infected cattle showed a strong humoral response to recombinant Apa by Western blot and ELISA. Milk was also a suitable sample to be tested by ELISA. We comparatively analysed the humoral cross-reactivity to the Apa from MPTB (MPTB-Apa) and the orthologue from
Mycobacterium tuberculosis (MT-Apa, identical to that from
Mycobacterium bovis) in both infected and control cows. Response of
M. bovis- and MPTB-infected animals against MT-Apa was similar (
P
=
0.6985) but the response of the
M. bovis-infected ones to MPTB-Apa was differential, being significantly diminished (
P
<
0.0001). Although 6 out 45 animals from MPTB-infected herds responded to MPTB-Apa stimulation in the IFNγ release assay, we found no significant differences when compared infected herds with non-infected ones (
P
=
0.34). This antigen, in contrast to bovine Purified Protein Derivative (PPDb), was strongly represented in avian PPD (PPDa), as shown by the recognition of BALB/c mice hyperimmune sera against MPTB-Apa by Dot-blot immunoassay. We therefore demonstrated the antigenicity of Apa in MPTB-infected animals and a differential response to the recombinant antigen when compared to
M. bovis-infected animals. These traits herein described, added to the usefulness of milk samples to detect IgG anti-Apa, could be important for routine screening in dairy cattle, considering a multiantigenic approach to overcome the lack of immunodominance.
Biological, spectroscopic and structural studies of a complex of Cobalt(II) with sulfaquinoxaline and 2,2′-bipyridine as ligands were carried out. Cytotoxicity was studied in the human osteosarcoma ...cell line (MG-63). Antibactericidal capacity was tested against four strains (Gram positive and negative bacteria). The aquatic toxicity was tested on two fish species. Display omitted
•A complex of Cobalt(II) with sulfaquinoxaline and Bpym as ligands has been prepared.•The complex has been characterized based on FTIR and Raman spectroscopy.•The aquatic toxicity was evaluated on the Danio rerio y Cyprinus carpio haematopterus.•Antibacterial activity was screened: E. coli, S. typhimurium, S. aureus and B. cereus.•The antiproliferative effect was studied in the human osteoblast MG-63 cell line.
A novel ternary complex of Cobalt(II) with 4-amino-N-2-quinoxalinylbenzenesulfonamide (sulfaquinoxaline, SQO), and 2,2′-bipyrimidine (Bpym) as ligands has been prepared. The complex has been characterized based on elemental analyses, FTIR and Raman spectroscopy. Its structure, Co(SQO)2(Bpym) was determined by X-ray diffraction methods. It crystallizes in the triclinic P1¯ space group with a=10.5381(2), b=13.6469(2), c=13.8409(3)Å, α=95.058(2)°, β=93.769(2)°, γ=93.750(2)° and Z=2 molecules per unit cell. Thermogravimetric (TG) and differential thermal analysis (DT) were also studied.
The aquatic toxicity of the complex was evaluated on the two following test organisms: Danio rerio (cebritas) y Cyprinus carpio haematopterus (carpas koi). Antibacterial activity was screened against Escherichia coli (ATCC 8739), Salmonella typhimurium (ATCC 14028), Staphylococcus aureus (ATCC 49775) and Bacillus cereus (ATCC 10987). The antiproliferative effect of the tested complex Co(SQO)2(Bpym) in the human osteoblast (MG-63) cell line was also studied.
The effect of speed and milling time on the morphology, crystallite size, and phase composition of Ti Cp powders processed in n-hexane by high-energy ball milling (HEBM) using a E-max Retsch ...equipment was studied by scanning electron microscopy (SEM), X-ray diffraction (XRD), and transmission electron microscopy (TEM). Lattice parameters, mean crystallite size, lattice strain, and dislocation density were obtained from Rietveld analysis. The XRD and TEM results show that the HEBM process of the Ti Cp promotes the transition from HCP to FCC after 6 h of milling at 1400 rpm. The transformation process could be attributed to the energy generated in the milling process which induces high deformation and presence of high-density dislocations in the powder.
Graphical Abstract
Studies about the tribological behavior of Ni–P–TiO
2
coatings on magnesium alloys are very scarce and the wear mechanisms involved are not analyzed. In this work, Ni–P and Ni–P/Ni–P–TiO
2
...nanocomposite coatings have been formed on AZ91D magnesium alloy by direct electroless technique with multiple steps, avoiding both the use of Cr(VI) compounds and the HF activation procedure. This work focused on two main aspects: (i) the formation of the composite coatings with different sizes and concentrations of TiO
2
nanoparticles, studying their morphology and chemical composition, and (ii) the study of the tribological properties of the coatings under dry sliding conditions. For tribological and mechanical evaluation, dry sliding friction and wear testing and nanoindentation measurements were performed. Scanning electron microscopy equipped with energy-dispersive X-ray (SEM/EDX) and X-ray diffraction (XRD) was used for the characterization of the coatings. Wear tracks and debris were analyzed by means micro-Raman spectroscopy and SEM/EDX. The addition of TiO
2
nanoparticles decreases the wear rate and improves the tribological behavior of the coatings. The wear mechanisms involve flattening of the nodules and abrasive wear to three bodies, accompanied by tribo-oxidation.
Glycerol-3-phosphate dehydrogenase (GPDH) catalyzes the conversion of dihydroxyacetone phosphate (DHAP) and NADH to glycerol-3-phosphate (G3P) and NAD+. G3P is important as a precursor for glycerol ...and glycerolipid synthesis in microalgae. A GPDH enzyme has been previously purified from the green microalga Chlamydomonas reinhardtii, however, no genes coding for GPDH have been characterized before. In this study, we report the in silico characterization of three putative GPDH genes from C. reinhardtii: CrGPDH1, CrGPDH2, and CrGPDH3. These sequences showed a significant similarity to characterized GPDH genes from the microalgae Dunaliella salina and Dunaliella viridis. The prediction of the three-dimensional structure of the proteins showed the characteristic fold topology of GPDH enzymes. Furthermore, the phylogenetic analysis showed that the three CrGPDHs share the same clade with characterized GPDHs from Dunaliella suggesting a common evolutionary origin and a similar catalytic function. In addition, the K a/K s ratios of these sequences suggested that they are under purifying selection. Moreover, the expression analysis showed a constitutive expression of CrGPDH1, while CrGPDH2 and CrGPDH3 were induced in response to osmotic stress, suggesting a possible role for these two sequences in the synthesis of glycerol as a compatible solute in osmoregulation, and perhaps also in lipid synthesis in C. reinhardtii. This study has provided a foundation for further biochemical and genetic studies of the GPDH family in this model microalga, and also opportunities to assess the potential of these genes to enhance the synthesis of TAGs for biodiesel production.
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