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https://www.readbyqxmd.com/read/28927194/finding-a-facile-way-for-the-bacterial-dna-transformation-by-biosynthesized-gold-nanoparticles
#1
Madhuree Kumari, Shipra Pandey, Aradhana Mishra, Chandra Shekhar Nautiyal
The major problem encountered during genetic manipulation of bacteria is the inability to get transformed because of their natural non-competency. In this study, to overcome this problem, a cost-effective method was developed by combining the properties of gold nanoparticles (GNPs) and the Yoshida effect. Various parameters, including GNP:plasmid ratio, pH and time, were optimized for stability of the GNP-plasmid conjugate. With non-competent Gram-negative cells, the efficiency ranged between 0.1 and 0.45 × 104 transformants μg-1, while the range was (0...
July 3, 2017: FEMS Microbiology Letters
https://www.readbyqxmd.com/read/28926883/-etiological-analysis-and-in-vitro-drug-sensitivity-of-bacterial-keratitis-in-northern-china-in-the-period-of-2006-2015
#2
Y Zhang, Z Q Wang, X G Sun
Objective: To analyze the etiology and drug sensitivity of bacterial keratitis and their changes, and to provide evidence for treatment and drug selection of bacterial keratitis. Methods: Retrospective case series study. From January 2006 to December 2015, corneal specimens suspected of bacterial infection were collected and cultured in Beijing Tongren Eye Center. General information of patients, etiological results and drug sensitivity test results were summarized and analyzed. The Chi-square test and Spearman correlation analysis were performed using SPSS 20...
September 11, 2017: [Zhonghua Yan Ke za Zhi] Chinese Journal of Ophthalmology
https://www.readbyqxmd.com/read/28926282/bacterial-and-archaeal-lipids-recovered-from-subsurface-evaporites-of-dalangtan-playa-on-the-tibetan-plateau-and-their-astrobiological-implications
#3
Ziye Cheng, Long Xiao, Hongmei Wang, Huan Yang, Jingjing Li, Ting Huang, Yi Xu, Nina Ma
Qaidam Basin (Tibetan Plateau) is considered an applicable analogue to Mars with regard to sustained extreme aridity and abundant evaporites. To investigate the possibility of the preservation of microbial lipids under these Mars analog conditions, we conducted a mineralogical and organic geochemistry study on samples collected from two Quaternary sections in Dalangtan Playa, northwestern Qaidam Basin, which will enhance our understanding of the potential preservation of molecular biomarkers on Mars. Two sedimentary units were identified along two profiles: one salt unit characterized by a predominance of gypsum and halite, and one detrital unit with a decrease of gypsum and halite and enrichment in siliciclastic minerals...
September 19, 2017: Astrobiology
https://www.readbyqxmd.com/read/28925956/sulfadiazine-salicylaldehyde-based-schiff-bases-synthesis-antimicrobial-activity-and-cytotoxicity
#4
Martin Krátký, Magdaléna Dzurková, Jiří Janoušek, Klára Konečná, František Trejtnar, Jiřina Stolaříková, Jarmila Vinšová
The resistance among microbes has brought an urgent need for new drugs. Thus, we synthesized a series of Schiff bases derived from the sulfa drug sulfadiazine and various salicylaldehydes. The resulting 4-[(2-hydroxybenzylidene)amino]-N-(pyrimidin-2-yl)benzene-sulfonamides were characterized and evaluated against Gram-positive and Gram-negative bacteria, yeasts, moulds, Mycobacterium tuberculosis, nontuberculous mycobacteria (M. kansasii, M. avium) and their cytotoxicity was determined. Among bacteria, the genus Staphylococcus, including methicillin-resistant S...
September 19, 2017: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
https://www.readbyqxmd.com/read/28925946/development-and-biocompatibility-evaluation-of-photocatalytic-tio%C3%A2-reduced-graphene-oxide-based-nanoparticles-designed-for-self-cleaning-purposes
#5
Ionela Cristina Nica, Miruna S Stan, Marcela Popa, Mariana Carmen Chifiriuc, Gratiela G Pircalabioru, Veronica Lazar, Iuliana Dumitrescu, Lucian Diamandescu, Marcel Feder, Mihaela Baibarac, Marin Cernea, Valentin Adrian Maraloiu, Traian Popescu, Anca Dinischiotu
Graphene is widely used in nanotechnologies to amplify the photocatalytic activity of TiO₂, but the development of TiO₂/graphene composites imposes the assessment of their risk to human and environmental health. Therefore, reduced graphene oxide was decorated with two types of TiO₂ particles co-doped with 1% iron and nitrogen, one of them being obtained by a simultaneous precipitation of Ti(3+) and Fe(3+) ions to achieve their uniform distribution, and the other one after a sequential precipitation of these two cations for a higher concentration of iron on the surface...
September 19, 2017: Nanomaterials
https://www.readbyqxmd.com/read/28925518/chemistry-of-peptidoglycan-in-mycobacterium-tuberculosis-life-style-an-off-the-wall-balance-of-synthesis-and-degradation
#6
Flavia Squeglia, Alessia Ruggiero, Rita Berisio
The cell wall envelope of mycobacteria is structurally distinct from that of both Gram-positive and Gram-negative bacteria. In Mycobacterium tuberculosis, this cell wall has unique structural features and plays a crucial role in drug resistance and macrophage survival under stress conditions. Peptidoglycan is the major constituent of this cell wall, with an important structural role, giving structural strength, and counteracting the osmotic pressure of the cytoplasm. Synthesis of this complex polymer takes place in three stages that occur at three different locations in the cell, from the cytoplasm to the external side of the cell membrane, where polymerization occurs...
September 19, 2017: Chemistry: a European Journal
https://www.readbyqxmd.com/read/28925099/highly-efficiency-antibacterial-diblock-copolypeptides-based-on-lysine-and-phenylalanine
#7
Xiaokai Su, Xinyu Zhou, Zhengzhong Tan, Chuncai Zhou
A series of amphiphilic diblock copolypeptides (K30 -b-F15 , K30 -b-F30 , and K30 -b-F45 ) were synthesized via N-carboxy-α-amino-anhydride ring-opening polymerization. The copolypeptides had excellent antibacterial efficacy to both Gram positive (S. aureus) and Gram negative (E. coli) bacteria. The minimum inhibitory concentrations (MICs) against E. coli and S. aureus are 8 μg mL(-1) and 2 μg mL(-1) , respectively, lower than most natural and artificial antimicrobial peptides (AMPs). The morphological changes of the bacteria treated with diblock copolypeptides were investigated by transmission electron microscopy; the results proved that the diblock copolypeptides had a similar antibacterial pore-forming mechanism to natural cationic peptides...
September 19, 2017: Biopolymers
https://www.readbyqxmd.com/read/28924925/in-vitro-activity-of-linezolid-alone-and-combined-with-other-antibiotics-against-clinical-enterococcal-isolates
#8
Mahtab Beitdaghar, Roya Ahmadrajabi, Afsaneh Karmostaji, Fereshteh Saffari
BACKGROUND: The increasing incidence of antimicrobial resistance has led to research on finding new antimicrobial agents or identifying drug combinations with synergistic effects. Enterococcal infections, particularly those associated with vancomycin-resistant enterococci (VREs), are therapeutic problems. Linezolid (LZD), an oxazolidinone antibiotic, shows good activity against Gram-positive bacteria including enterococci. To avoid the emergence of linezolid-resistant subpopulations and achieve enhanced activity or bactericidal effect, the use of combined therapy has been considered...
September 18, 2017: Wiener Medizinische Wochenschrift
https://www.readbyqxmd.com/read/28924631/new-features-in-the-lipid-a-structure-of-brucella-suis-and-brucella-abortus-lipopolysaccharide
#9
Adriana C Casabuono, Cecilia Czibener, Mariela G Del Giudice, Ezequiel Valguarnera, Juan E Ugalde, Alicia S Couto
Brucellaceae are Gram-negative bacteria that cause brucellosis, one of the most distributed worldwide zoonosis, transmitted to humans by contact with either infected animals or their products. The lipopolysaccharide exposed on the cell surface has been intensively studied and is considered a major virulence factor of Brucella. In the last years, structural studies allowed the determination of new structures in the core oligosaccharide and the O-antigen of this lipopolysaccharide. In this work, we have reinvestigated the lipid A structure isolated from B...
September 18, 2017: Journal of the American Society for Mass Spectrometry
https://www.readbyqxmd.com/read/28923702/zinc-oxide-nanoparticles-synthesis-antiseptic-activity-and-toxicity-mechanism
#10
REVIEW
A Król, P Pomastowski, K Rafińska, V Railean-Plugaru, B Buszewski
Zinc oxide (ZnO), as a material with attractive properties, has attracted great interest worldwide, particularly owing to the implementation of the synthesis of nano-sized particles. High luminescent efficiency, a wide band gap (3.36eV), and a large exciton binding energy (60meV) has triggered intense research on the production of nanoparticles using different synthesis methods and on their future applications. ZnO nanomaterials can be used in industry as nano-optical and nano-electrical devices, in food packaging and in medicine as antimicrobial and antitumor agents...
August 26, 2017: Advances in Colloid and Interface Science
https://www.readbyqxmd.com/read/28923606/actinomycetes-benefaction-role-in-soil-and-plant-health
#11
REVIEW
Asma Absar Bhatti, Shamsul Haq, Rouf Ahmad Bhat
Actinomycetes are aerobic, spore forming gram-positive bacteria, belonging to the order actinomycetales characterized with substrate and aerial mycelium growth. They are the most abundant organisms that form thread-like filaments in the soil and are responsible for characteristically "earthy" smell of freshly turned healthy soil. They play major roles in the cycling of organic matter; inhibit the growth of several plant pathogens in the rhizosphere and decompose complex mixtures of polymer in dead plant, animal and fungal material results in production of many extracellular enzymes which are conductive to crop production...
September 16, 2017: Microbial Pathogenesis
https://www.readbyqxmd.com/read/28923605/microbial-pathogenicity-and-virulence-mediated-by-integrons-on-gram-positive-microorganisms
#12
REVIEW
Yanmei Li, Ling Yang, Jie Fu, Muxia Yan, Dingqiang Chen, Li Zhang
Gram-positive microorganisms are one of leading pathogenic microorganisms in public health, including several typical "Super Bugs" as methicillin-resistant Staphylococcus aureus, Klebsiella pneumoniae carbapenemase and vancomycin-resistant enterococci, which caused a increasement of infections, clinical failures and expenses. Regarded as a common genetic element responsible for horizontal gene transfer, integrons are widely distributed in various pathogens considered as a determinant in the acquisition and evolution of antibiotic resistance...
September 15, 2017: Microbial Pathogenesis
https://www.readbyqxmd.com/read/28923604/study-on-the-excision-and-integration-mediated-by-class-1-integron-in-streptococcus-pneumoniae
#13
Qun Lin, Pusheng Xu, Jiaowu Li, Jinhua Huang, Yin Chen, Shuhuan Deng
As a novel antibiotic resistance mobile element, integron was recognized as a primary source of antibiotic genes among Gram-positive organisms for its excision and integration of exogenous genes. In this study, Streptococcus pneumoniae was subjected to investigate the excision and integration of class 1 integron with eight different plasmids. As the results indicated, excision in both att site and gene cassettes were successfully observed, which was further confirmed by integration assays and PCR amplification...
September 16, 2017: Microbial Pathogenesis
https://www.readbyqxmd.com/read/28923592/comparative-study-of-three-c1q-domain-containing-proteins-from-pacific-oyster-crassostrea-gigas
#14
Zhao Lv, Limei Qiu, Mengqiang Wang, Zhihao Jia, Weilin Wang, Lusheng Xin, Zhaoqun Liu, Lingling Wang, Linsheng Song
C1q domain containing proteins (C1qDCs) are a family of proteins containing a globular head C1q domain (ghC1q) in C-terminus, which serve as pattern recognition receptors (PRRs) and mediate a series of immune responses. In the present study, three C1qDC proteins from Pacific oyster Crassostrea gigas (CgC1qDC-2, CgC1qDC-3, CgC1qDC-4) were characterized and comparatively investigated to understand their roles in the immune response. All the three recombinant CgC1qDC proteins (rCgC1qDCs) could bind lipopolysaccharide (LPS) significantly but they could not bind lipoteichoic acid (LTA), β-1,3-glucan (GLU), mannan (MAN), and polyinosinic-polycytidylic acid (Poly I:C)...
September 16, 2017: Developmental and Comparative Immunology
https://www.readbyqxmd.com/read/28923566/fabrication-of-antibacterial-chitosan-pva-blended-film-using-electrospray-technique-for-food-packaging-applications
#15
Yaowen Liu, Shuyao Wang, Wenting Lan
In this study, blended films from poly(vinyl alcohol) (PVA) containing chitosan (CS) were prepared via a simple solution casting and electrospraying method. The structures of the PVA-CS films were characterized by Fourier-transform infrared spectroscopy. The morphologies of the films were observed by scanning electron microscopy. The thermal properties of the PVA-CS films were examined by thermogravimetry. The effects of CS contents on the mechanical properties, oxygen permeability values, water vapor permeation levels, and antibacterial behaviors against Gram-negative (Escherichia coli) and Gram-positive (Staphylococcus aureus) strains were investigated...
September 15, 2017: International Journal of Biological Macromolecules
https://www.readbyqxmd.com/read/28923564/multi-step-synthesis-spectroscopic-studies-of-biological-active-steroidal-thiosemicarbazones-and-their-palladium-ii-complex-as-macromolecules
#16
Salman A Khan, Abdullah M Asiri
Steroidal Pd (II) metal complexes were synthesized by the reaction of steroidal thiosemicarbazones with [Pd (DMSO)2 Cl2]. The steroidal thiosemicarbazones coordinate to palladium through the azomethine nitrogen and thionic sulfur. The thiosemicarbazone derivatives were obtained by the reaction of thiosemicarbazide with steroidal ketones. The identity of steroidal thiosemicarbazones and their Pd(II) metal complexes were elucidated by IR, (1)H, (13)C NMR, FAB mass spectroscopic methods, elemental analysis and TGA analysis...
September 15, 2017: International Journal of Biological Macromolecules
https://www.readbyqxmd.com/read/28923525/morphological-and-functional-characterization-of-the-hemocytes-from-the-pearl-oyster-pteria-hirundo-and-their-immune-responses-against-vibrio-infections
#17
Graziela Cleuza Vieira, Patrícia Mirella da Silva, Margherita Anna Barracco, Augusto Ferrari Hering, Marcos Caivano Pedroso de Albuquerque, Jaqueline da Rosa Coelho, Éder Carlos Schmidt, Zenilda Laurita Bouzon, Rafael Diego Rosa, Luciane Maria Perazzolo
Hemocyte populations of the pearl oyster Pteria hirundo were characterized at morphological, ultrastructural and functional levels. Three main hemocyte populations were identified: hyalinocytes, granulocytes and blast-like cells. Hyalinocytes were the most abundant population (88.2%) characterized by the presence of few or no granules in the cytoplasm and composed by two subpopulations, large and small hyalinocytes. Comparatively, granulocytes represented 2.2% of the hemocyte population and were characterized by the presence of numerous large electron-lucid granules in the cytoplasm...
September 16, 2017: Fish & Shellfish Immunology
https://www.readbyqxmd.com/read/28923470/tripodal-lipoprotein-variants-with-c-terminal-hydrophobic-residues-allosterically-modulate-activity-of-the-degp-protease
#18
Hyojin Park, Yurie T Kim, Chulwon Choi, Seokhee Kim
DegP, a member of the highly conserved HtrA family of proteases, performs a regulated proteolysis of toxic misfolded proteins in the periplasm of Gram-negative bacteria. The allosteric switch between inactive and active conformations is a central mechanism to carefully control proteolytic activity of DegP and to maintain the optimal cellular fitness, but few other molecules than substrates are known to allosterically control DegP activity. Here, we demonstrate that a mutant variant of an outer membrane lipoprotein, Lpp(+Leu), can function as a novel allosteric effector that changes the dynamic range of DegP activity...
September 15, 2017: Journal of Molecular Biology
https://www.readbyqxmd.com/read/28922803/micropredator-niche-differentiation-between-bulk-soil-and-rhizosphere-of-an-agricultural-soil-depends-on-bacterial-prey
#19
Lu Zhang, Tillmann Lueders
Predation is a fundamental mechanism of all food webs, but its drivers and organismic connectivities, especially at microbial level, are still poorly understood. Specifically, competitive carbon flows in the presence of multiple micropredators, as well as trophic links within and between microbial kingdoms have rarely been resolved. Here, using maize-planted agricultural soil as a model system, we have investigated the predation of amended bacterial prey by both prokaryotic and eukaryotic micropredators. We have queried how soil compartment (rhizosphere vs bulk soil) and nature of prey (Gram-positive vs Gram-negative) influence predation outcomes...
September 1, 2017: FEMS Microbiology Ecology
https://www.readbyqxmd.com/read/28922505/enhancing-the-antimicrobial-activity-of-alamethicin-f50-5-by-incorporating-n-terminal-hydrophobic-triazole-substituents
#20
Sanjit Das, Khoubaib Ben Haj Salah, Emmanuel Wenger, Jean Martinez, Jules Kotarba, Vanessa Andreu, Nicolas Ruiz, Filippo Savini, Lorenzo Stella, Claude Didierjean, Baptiste Legrand, Nicolas Inguimbert
We propose a simple and efficient strategy to significantly improve the antibacterial activity of peptaibols and other antimicrobial peptides by N-terminal capping with 1,2,3-triazole bearing various hydrophobic substituents on C-4. We showed, herein, that such N-terminal insertions on alamethicin F50/5 could enhance its antimicrobial activity on gram-positive bacteria without modification of its overall three-dimensional structure. Indeed, while the native peptide and its analogues shared comparable helical contents, the crystal structure of one of the most active derivative showed a local slight distortion of the N-terminal extremity, which was also observed in solution using NMR spectroscopy...
September 18, 2017: Chemistry: a European Journal
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