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Matthew G Iadanza, Anna J Higgins, Bob Schiffrin, Antonio N Calabrese, David J Brockwell, Alison E Ashcroft, Sheena E Radford, Neil A Ranson
The β-barrel assembly machinery (BAM) is a ∼203 kDa complex of five proteins (BamA-E), which is essential for viability in E. coli. BAM promotes the folding and insertion of β-barrel proteins into the outer membrane via a poorly understood mechanism. Several current models suggest that BAM functions through a 'lateral gating' motion of the β-barrel of BamA. Here we present a cryo-EM structure of the BamABCDE complex, at 4.9 Å resolution. The structure is in a laterally open conformation showing that gating is independent of BamB binding...
2016: Nature Communications
Chaman Ranjit, Kenneth M Noll
Thermotoga maritima cells are distinguished by a sheath-like structure called the toga that loosely encloses single or multiple cells. During growth, and particularly at late phases of population growth, the toga distends from the poles of many cells. Little is known about this phenomenon so this study presents basic information about this process. We first provide quantitative data demonstrating that cells showing toga distensions increase in number during growth and that the phenomenon is not due to acidification of their growth medium...
October 2016: FEMS Microbiology Letters
Kenzo Ichimura, Tetsuya Matoba, Kaku Nakano, Masaki Tokutome, Katsuya Honda, Jun-Ichiro Koga, Kensuke Egashira
BACKGROUND: There is an unmet need to develop an innovative cardioprotective modality for acute myocardial infarction, for which interventional reperfusion therapy is hampered by ischemia-reperfusion (IR) injury. We recently reported that bioabsorbable poly(lactic acid/glycolic acid) (PLGA) nanoparticle-mediated treatment with pitavastatin (pitavastatin-NP) exerts a cardioprotective effect in a rat IR injury model by activating the PI3K-Akt pathway and inhibiting inflammation. To obtain preclinical proof-of-concept evidence, in this study, we examined the effect of pitavastatin-NP on myocardial IR injury in conscious and anesthetized pig models...
2016: PloS One
Yi Li, Yujia Wang, Qiong Wu, Li Li, Yujun Shi, Hong Bu, Ji Bao
Successful porcine hepatocyte isolation is crucial for the development of bioartificial liver devices and hepatocyte transplantation. Serva collagenase NB grades are formulated collagenases that are suitable for various tissue isolation applications. N-acetylcysteine (NAC) can improve the viability of human hepatocytes. The aim of this study was to compare the effectiveness of two collagenases and effect of NAC on hepatocyte isolation from porcine liver tissue. Porcine hepatocytes were isolated using the perfusion method from Bama mini pigs assigned to the Serva NB 4 group (n=6), the Serva NB 8 group (n=6), or the NB 8+NAC group (n=6)...
September 2016: Xenotransplantation
Henna Iqbal, Melisha R Kenedy, Meghan Lybecker, Darrin R Akins
Two outer membrane protein (OMP) transport systems in diderm bacteria assist in assembly and export of OMPs. These two systems are the β-barrel assembly machine (BAM) complex and the translocation and assembly module (TAM). The BAM complex consists of the OMP component BamA along with several outer membrane associated proteins. The TAM also consists of an OMP, designated TamA, and a single inner membrane (IM) protein, TamB. Together TamA and TamB aid in the secretion of virulence-associated OMPs. In this study we characterized the hypothetical protein BB0794 in Borrelia burgdorferi...
September 2, 2016: Molecular Microbiology
Yuanyuan Pan, Fang Wang, Da-Wen Sun, Quanyang Li
This study aimed to investigate the relationship between the intestinal Lactobacillus species and diet of elderly subjects in a longevity area in Southern China. Healthy elderly subjects ranging from 80 to 99 years old were respectively selected from the regions of Bama and Nanning, Guangxi, China. The nested polymerase chain reaction and denaturing gradient gel electrophoresis (PCR-DGGE) technology was used to analyze the intestinal Lactobacillus community structure. Results showed that Weissella confusa, L...
September 2016: Journal of Microbiology / the Microbiological Society of Korea
Zi-Min Tang, Si-Ling Wang, Dong Ying, Gui-Ping Wen, Wei Cai, Ke Zhang, Wen-Fang Ji, Ming Yang, Zi-Zheng Zheng, Ning-Shao Xia
The hepatitis E virus (HEV) is one of the main causes of enterically transmitted hepatitis worldwide. Although the mortality rates associated with HEV are generally low, they can be up to 28% in HEV-infected pregnant women, and the elderly are more susceptible. The reasons for this selective severity are unclear, partially because there is no suitable, easy-to-use model in which to study HEV infection. Non-human primates and standard swine have been identified as being sensitive to infection with HEV and have been used for HEV infection studies...
2016: Scientific Reports
H M Zhao, H Yang, F H Luo, M X Li, S Zhang, X G Yang, Y Q Lu, S S Lu, Y J Wu, K H Lu
Spermatogonial stem cells (SSCs), the unique seed cells of testes, can undergo meiosis and form spermatozoa, thus transmitting genetic information to offspring. Research concerning these cells explores the mechanism underlying spermatogenesis, making possible the induction of their differentiation into spermatozoa in vitro. SSCs have therefore attracted much interest among scientists. Although the proliferation of such cells in vitro has been demonstrated, we are unaware of any long-term laboratory culture of porcine SSCs...
2016: Genetics and Molecular Research: GMR
James Lee, Mingyu Xue, Joseph S Wzorek, Tao Wu, Marcin Grabowicz, Luisa S Gronenberg, Holly A Sutterlin, Rebecca M Davis, Natividad Ruiz, Thomas J Silhavy, Daniel E Kahne
The assembly of β-barrel proteins into membranes is mediated by an evolutionarily conserved machine. This process is poorly understood because no stable partially folded barrel substrates have been characterized. Here, we slowed the folding of the Escherichia coli β-barrel protein, LptD, with its lipoprotein plug, LptE. We identified a late-stage intermediate in which LptD is folded around LptE, and both components interact with the two essential β-barrel assembly machine (Bam) components, BamA and BamD...
August 2, 2016: Proceedings of the National Academy of Sciences of the United States of America
Haowen Yang, Ming Liu, Bingcong Zhou, Yan Deng, Nongyue He, Hesheng Jiang, Yafen Guo, Ganqiu Lan, Qinyang Jiang, Xiurong Yang, Zhiyang Li
Chinese Bama minipigs could be potential donors for the supply of xenografts because they are genetically stable, highly inbred, and inexpensive. However, porcine endogenous retrovirus (PERV) is commonly integrated in pig genomes and could cause a cross-species infection by xenotransplantation. For screening out the pigs with low copy numbers of PERV proviruses, we have developed a novel semiquantitative analysis approach based on magnetic nanoparticles (MNPs) and chemiluminescence (CL) for estimating relative copy numbers (RCNs) of PERV proviruses in Chinese Bama minipigs...
June 2016: Journal of Nanoscience and Nanotechnology
Y N Huang, Q W Ao, Q Y Jiang, Y F Guo, G Q Lan, H S Jiang
Bama Xiang and Landrace pigs are the local fatty and lean breeds, respectively, in China. We compared differences in carcass traits, meat quality traits, and myosin heavy chain (MyHC) types in the longissimus dorsi muscles between Bama Xiang and Landrace pigs. This was done in pigs of the same age, using real-time PCR, to investigate the relationship between MyHC fiber types and carcass characteristics, meat quality traits, and the key factors regulating muscle fiber type. Bama Xiang pigs exhibited smaller size and slower growth than Landrace pigs (P < 0...
2016: Genetics and Molecular Research: GMR
Jintao Guo, Beibei Sun, Siyu Sun, Xiang Liu, Sheng Wang, Nan Ge, Guoxin Wang, Wen Liu
BACKGROUND AND STUDY AIMS: Closure of gastric wall defects after endoscopic full-thickness resection remains a clinical challenge. We aimed to introduce an endoscopic puncture-suture device (EPSD) for the closure of such defects. We evaluated the safety, efficacy, and outcomes of EPSD in gastric wall defect closure after endoscopic full-thickness resection, compared with the metallic clips closure method. METHODS: Twenty-four Bama mini pigs (20-25 kg) were randomly divided into 2 groups...
June 27, 2016: Gastrointestinal Endoscopy
Zachary C Ruhe, Josephine Y Nguyen, Annette J Chen, Nicole Y Leung, Christopher S Hayes, David A Low
Contact-dependent growth inhibition (CDI) systems are widespread amongst Gram-negative bacteria where they play important roles in inter-cellular competition and biofilm formation. CDI+ bacteria use cell-surface CdiA proteins to bind neighboring bacteria and deliver C-terminal toxin domains. CDI+ cells also express CdiI immunity proteins that specifically neutralize toxins delivered from adjacent siblings. Genomic analyses indicate that cdi loci are commonly found on plasmids and genomic islands, suggesting that these Type 5 secretion systems are spread through horizontal gene transfer...
June 2016: PLoS Genetics
Patrick J Fleming, Dhilon S Patel, Emilia L Wu, Yifei Qi, Min Sun Yeom, Marcelo Carlos Sousa, Karen G Fleming, Wonpil Im
The outer membrane of Gram-negative bacteria is an asymmetric membrane with lipopolysaccharides on the external leaflet and phospholipids on the periplasmic leaflet. This outer membrane contains mainly β-barrel transmembrane proteins and lipidated periplasmic proteins (lipoproteins). The multisubunit protein β-barrel assembly machine (BAM) catalyzes the insertion and folding of the β-barrel proteins into this membrane. In Escherichia coli, the BAM complex consists of five subunits, a core transmembrane β-barrel with a long periplasmic domain (BamA) and four lipoproteins (BamB/C/D/E)...
June 21, 2016: Biophysical Journal
Leonie van 't Hag, Hsin-Hui Shen, Tsung-Wu Lin, Sally L Gras, Calum J Drummond, Charlotte E Conn
A fundamental understanding of the effect of amphiphilic protein encapsulation on the nanostructure of the bicontinuous cubic phase is crucial to progressing biomedical and biological applications of these hybrid protein-lipid materials, including as drug delivery vehicles, as biosensors, biofuel cells and for in meso crystallization. The relationship between the lipid nanomaterial and the encapsulated protein, however, remains poorly understood. In this study, we investigated the effect of incorporating the five transmembrane and lipo-proteins which make up the β-barrel assembly machinery from Gram-negative bacteria within a series of bicontinuous cubic phases...
June 21, 2016: Langmuir: the ACS Journal of Surfaces and Colloids
Yan Wang, Rui Wang, Feng Jin, Yang Liu, Jiayu Yu, Xinmiao Fu, Zengyi Chang
β-barrel outer membrane proteins (OMPs) are ubiquitously present in Gram-negative bacteria, mitochondria and chloroplasts, and function in a variety of biological processes. The mechanism by which the hydrophobic nascent β-barrel OMPs are transported through the hydrophilic periplasmic space in bacterial cells remains elusive. Here, mainly via unnatural amino acid-mediated in vivo photo-crosslinking studies, we revealed that the primary periplasmic chaperone SurA interacts with nascent β-barrel OMPs largely via its N-domain but with β-barrel assembly machine protein BamA mainly via its satellite P2 domain, and that the nascent β-barrel OMPs interact with SurA via their N- and C-terminal regions...
August 5, 2016: Journal of Biological Chemistry
Gerard H M Huysmans
Since the discovery of the essential role of the β-barrel assembly machinery (BAM) for the membrane insertion of outer membrane proteins (OMPs) that are unrelated in sequence, members of this universally conserved family dominate discussions on OMP assembly in bacteria, mitochondria and chloroplasts. However, several multimeric bacterial OMPs assemble independently of the catalyzing BAM-component BamA. Recent progress on this alternative pathway is reviewed here, and a model for BAM-independent assembly for multimeric OMPs is proposed in which monomer delivery to the membrane and stable prepore formation are key steps towards productive membrane insertion...
June 15, 2016: Biochemical Society Transactions
Caitlin D Deane, Brandon J Burkhart, Patricia M Blair, Jonathan I Tietz, Alice Lin, Douglas A Mitchell
Plantazolicin (PZN) is a ribosomally synthesized and post-translationally modified peptide (RiPP) natural product that exhibits extraordinarily narrow-spectrum antibacterial activity toward the causative agent of anthrax, Bacillus anthracis. During PZN biosynthesis, a cyclodehydratase catalyzes cyclization of cysteine, serine, and threonine residues in the PZN precursor peptide (BamA) to azolines. Subsequently, a dehydrogenase oxidizes most of these azolines to thiazoles and (methyl)oxazoles. The final biosynthetic steps consist of leader peptide removal and dimethylation of the nascent N-terminus...
August 19, 2016: ACS Chemical Biology
Reza Dastvan, Eva-Maria Brouwer, Denise Schuetz, Oliver Mirus, Enrico Schleiff, Thomas F Prisner
Many proteins of the outer membrane of Gram-negative bacteria and of the outer envelope of the endosymbiotically derived organelles mitochondria and plastids have a β-barrel fold. Their insertion is assisted by membrane proteins of the Omp85-TpsB superfamily. These proteins are composed of a C-terminal β-barrel and a different number of N-terminal POTRA domains, three in the case of cyanobacterial Omp85. Based on structural studies of Omp85 proteins, including the five POTRA-domain-containing BamA protein of Escherichia coli, it is predicted that anaP2 and anaP3 bear a fixed orientation, whereas anaP1 and anaP2 are connected via a flexible hinge...
May 24, 2016: Biophysical Journal
Liang Ma, Xiu-Jun Cai, Hai-Hong Wang, Yan-Lan Yu, Di-Yu Huang, Guang-Ju Ge, Hai-Yi Hu, Shi-Cheng Yu
AIM: To explore the feasibility and safety of laparoscopic colonic anastomosis using a degradable stent in a porcine model. METHODS: Twenty Bama mini-pigs were randomly assigned to a stent group (n = 10) and control group (hand-sewn anastomosis, n = 10). The anastomotic completion and operation times were recorded, along with histological examination, postoperative general condition, complications, mortality, bursting pressure, and the average anastomotic circumference (AC)...
May 21, 2016: World Journal of Gastroenterology: WJG
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