The aim of this study was to analyse a florfenicol-resistant Mannheimia haemolytica isolated from a calf to determine the genetic basis of its florfenicol-resistance. The antimicrobial susceptibility and plasmid content of the isolate were determined. A florfenicol resistant plasmid carrying the floR gene was identified by PCR and transformed into Escherichia coli JM109 and HB101 strains. The plasmid was then mapped and sequenced completely. The isolate was resistant to chloramphenicol, florfenicol, oxytetracycline, kanamycin, dihydrostreptomycin, nalidixic acid, ampicillin, and amoxicillin; it carried a floR plasmid of 7.7kb, designated pMH1405. The mobilisation and replication genes of pMH1405 showed extensive similarity to the 5.1-kb pDN1 plasmid from Dichelobacter nodosus and the 10.8-kb pCCK381 plasmid from Pasteurella multocida. An adjacent 2.4-kb segment was highly homologous to the TnfloR region of the E. coli BN10660 plasmid. A plasmid-mediated floR gene was responsible for florfenicol resistance in the bovine respiratory tract pathogen M. haemolytica. The pMH1405 plasmid is the smallest floR-carrying plasmid reported to date. To the best of our knowledge, this is the first report of a florfenicol-resistant gene in M. haemolytica.
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http://dx.doi.org/10.1016/j.vetmic.2011.09.033 | DOI Listing |
J Vis Exp
January 2025
Genetics and Aging Research Unit, MassGeneral Institute for Neurodegenerative Disease, Henry and Allison McCance Center for Brain Health, Department of Neurology, Massachusetts General Hospital, Harvard Medical School;
A method to quantitate the stabilization of Mitochondria-Associated endoplasmic reticulum Membranes (MAMs) in a 3-dimensional (3D) neural model of Alzheimer's disease (AD) is presented here. To begin, fresh human neuro progenitor ReN cells expressing β-amyloid precursor protein (APP) containing familial Alzheimer's disease (FAD) or naïve ReN cells are grown in thin (1:100) Matrigel-coated tissue culture plates. After the cells reach confluency, these are electroporated with expression plasmids encoding red fluorescence protein (RFP)-conjugated mitochondria-binding sequence of AKAP1(34-63) (Mito-RFP) that detects mitochondria or constitutive MAM stabilizers MAM 1X or MAM 9X that stabilize tight (6 nm ± 1 nm gap width) or loose (24 nm ± 3 nm gap width) MAMs, respectively.
View Article and Find Full Text PDFAppl Microbiol Biotechnol
January 2025
Chair of Microbiology, Technical University of Munich, TUM School of Life Science, Emil-Ramann-Str. 4, 85354, Freising, Germany.
The anaerobic bacterium Clostridium cellulovorans is a promising candidate for the sustainable production of biofuels and platform chemicals due to its cellulolytic properties. However, the genomic engineering of the species is hampered because of its poor genetic accessibility and the lack of genetic tools. To overcome this limitation, a protocol for triparental conjugation was established that enables the reliable transfer of vectors for markerless chromosomal modification into C.
View Article and Find Full Text PDFNaunyn Schmiedebergs Arch Pharmacol
January 2025
School of Pharmacy, Jiangxi University of Chinese Medicine, Nanchang, China.
Microglia-mediated neuroinflammation plays a crucial role in Alzheimer's disease (AD). Tinosinenside A (Tis A) is a novel sesquiterpene glycoside isolated from the dried rattan stem of Tinospora sinensis (Lour.) Merr.
View Article and Find Full Text PDFInfect Immun
January 2025
Department of Microbiology and Immunology, University of Western Ontario, London, Ontario, Canada.
is a predominant cause of post-operative surgical site infections and persistent bacteremia. Here, we describe a patient who experienced three episodes of infection over a period of 4 months following a total knee arthroplasty. The initial bloodstream isolate (SAB-0429) was a clonal complex 5 (CC5) and methicillin-resistant (MRSA), whereas two subsequent isolates (SAB-0485 and SAB-0495) were CC5 isolates but methicillin-sensitive .
View Article and Find Full Text PDFiScience
February 2025
Department of Clinical Laboratory, Lishui People's Hospital, The Sixth Affiliated Hospital of Wenzhou Medical University, Lishui, Zhejiang, China.
Multidrug-resistant Typhimurium has emerged as a global public health concern. Asymptomatic gastrointestinal carriage is a key factor in the spread of antibiotic-resistant bacteria. However, it is challenging to obtain direct evidence of transfer of mobile genetic elements (MGEs).
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