Résumé
Tuberculosis (TB) and human immunodeficiency virus infection / acquired immune deficiency syndrome (HIV/AIDS) are both serious global public health threats. Early detection of infected persons and/or patients through TB/HIV bi-directional screening is crucial for prevention and control strategy in China and globally. In recent years, with the promotion and application of new TB and HIV detection technologies worldwide, TB/HIV bi-directional screening technologies and strategies have made remarkable changes. This expert consensus introduces the significance and challenges of TB/HIV bi-directional screening, summarizes important progress of research and applications, and makes recommendations on screening measures and procedures to further strengthen TB/HIV bi-directional screening in China.
Résumé
Magnetotactic bacteria (MTB), a group of phylogenetically diverse organisms that use their unique intracellular magnetosome organelles to swim along the Earth's magnetic field, play important roles in the biogeochemical cycles of iron and sulfur. Previous studies have revealed that the bacterial actin protein MamK plays essential roles in the linear arrangement of magnetosomes in MTB cells belonging to the Proteobacteria phylum. However, the molecular mechanisms of multiple-magnetosome-chain arrangements in MTB remain largely unknown. Here, we report that the MamK filaments from the uncultivated 'Candidatus Magnetobacterium casensis' (Mcas) within the phylum Nitrospirae polymerized in the presence of ATP alone and were stable without obvious ATP hydrolysis-mediated disassembly. MamK in Mcas can convert NTP to NDP and NDP to NMP, showing the highest preference to ATP. Unlike its Magnetospirillum counterparts, which form a single magnetosome chain, or other bacterial actins such as MreB and ParM, the polymerized MamK from Mcas is independent of metal ions and nucleotides except for ATP, and is assembled into well-ordered filamentous bundles consisted of multiple filaments. Our results suggest a dynamically stable assembly of MamK from the uncultivated Nitrospirae MTB that synthesizes multiple magnetosome chains per cell. These findings further improve the current knowledge of biomineralization and organelle biogenesis in prokaryotic systems.
Sujets)
Actines , Chimie , Métabolisme , Adénosine triphosphate , Métabolisme , Bactéries , Classification , Métabolisme , Protéines bactériennes , Chimie , Métabolisme , Magnetospirillum , Classification , Métabolisme , Nucléotides , Métabolisme , Phylogenèse , Spécificité du substratRésumé
Raman spectroscopy has generated many branches during the development for more than 90 years. Surface enhanced Raman spectroscopy (SERS) improves SNR by using the interaction between tested materials and the surface of rough metal, as to quickly get higher sensitivity and precision spectroscopy without sample pretreatment. This article describes the characteristic and classification of SERS, and updates the theory and clinical application of SERS. It also summarizes the present status and progress of SERS in various disciplines and illustrates the necessity and urgency of its research, which provides rationale for the application for SERS in microbiology.