We investigated the role of the endoplasmic reticulum (ER) stress response in intracellular Ca 2؉ regulation, MAPK activation, and cytoprotection in LLC-PK 1 renal epithelial cells in an attempt to identify the mechanisms of protection afforded by ER stress. Cells preconditioned with trans-4,5-dihydroxy-1,2-dithiane, tunicamycin, thapsigargin, or A23187 expressed ER stress proteins and were resistant to subsequent H 2 O 2 -induced cell injury. In addition, ER stress preconditioning prevented the increase in intracellular Ca 2؉ concentration that normally follows H 2 O 2 exposure. Stable transfection of cells with antisense RNA targeted against GRP78 (pkASgrp78 cells) prevented GRP78 induction, disabled the ER stress response, sensitized cells to H 2 O 2 -induced injury, and prevented the development of tolerance to H 2 O 2 that normally occurs with preconditioning. ERK and JNK were transiently (30 -60 min) phosphorylated in response to H 2 O 2 . ER stress-preconditioned cells had more ERK and less JNK phosphorylation than control cells in response to H 2 O 2 exposure. Preincubation with a specific inhibitor of JNK activation or adenoviral infection with a construct that encodes constitutively active MEK1, the upstream activator of ERKs, also protected cells against H 2 O 2 toxicity. In contrast, the pkASgrp78 cells had less ERK and more JNK phosphorylation upon H 2 O 2 exposure. Expression of constitutively active ERK also conferred protection on native as well as pkASgrp78 cells. These results indicate that GRP78 plays an important role in the ER stress response and cytoprotection. ER stress preconditioning attenuates H 2 O 2 -induced cell injury in LLC-PK 1 cells by preventing an increase in intracellular Ca 2؉ concentration, potentiating ERK activation, and decreasing JNK activation. Thus, the ER stress response modulates the balance between ERK and JNK signaling pathways to prevent cell death after oxidative injury. Furthermore, ERK activation is an important downstream effector mechanism for cellular protection by ER stress.

Identification of novel cellular proteins as substrates to viral proteases would provide a new insight into the mechanism of cell–virus interplay. Eight nuclear proteins as potential targets for enterovirus 71 (EV71) 3C protease (3Cpro) cleavages were identified by 2D electrophoresis and MALDI-TOF analysis. Of these proteins, CstF-64, which is a critical factor for 3′ pre-mRNA processing in a cell nucleus, was selected for further study. A time-course study to monitor the expression levels of CstF-64 in EV71-infected cells also revealed that the reduction of CstF-64 during virus infection was correlated with the production of viral 3Cpro. CstF-64 was cleaved in vitro by 3Cpro but neither by mutant 3Cpro (in which the catalytic site was inactivated) nor by another EV71 protease 2Apro. Serial mutagenesis was performed in CstF-64, revealing that the 3Cpro cleavage sites are located at position 251 in the N-terminal P/G-rich domain and at multiple positions close to the C-terminus of CstF-64 (around position 500). An accumulation of unprocessed pre-mRNA and the depression of mature mRNA were observed in EV71-infected cells. An in vitro assay revealed the inhibition of the 3′-end pre-mRNA processing and polyadenylation in 3Cpro-treated nuclear extract, and this impairment was rescued by adding purified recombinant CstF-64 protein. In summing up the above results, we suggest that 3Cpro cleavage inactivates CstF-64 and impairs the host cell polyadenylation in vitro, as well as in virus-infected cells. This finding is, to our knowledge, the first to demonstrate that a picornavirus protein affects the polyadenylation of host mRNA.

SARS-CoV-2 has infected millions of people and is on a trajectory to kill more than one million globally. Virus entry depends on the receptor-binding domain (RBD) of the spike protein. Although previous studies demonstrated anti-spike and -RBD antibodies as essential for protection and convalescent plasma as a promising therapeutic option, little is known about the immunoglobulin (Ig) isotypes capable of blocking virus entry. Here, we studied spike- and RBD-specific Ig isotypes in plasma/sera from two acutely infected and 29 convalescent individuals. Spike- and RBD-specific IgM, IgG1, and IgA1 antibodies were produced by all or nearly all subjects at varying levels and detected at 7-8 days post-disease onset. IgG2, IgG3, IgG4, and IgA2 were also present but at much lower levels. All samples also displayed neutralizing activity. IgM, IgG, and IgA were capable of mediating neutralization, but neutralization titers correlated better with binding levels of IgM and IgA1 than IgG.

Intragastric inoculation of mice with Klebsiella pneumoniae can cause liver abscesses, necrosis of liver tissues, and bacteremia. A newly isolated phage (NK5) with lytic activity for K. pneumoniae was used to treat K. pneumoniae infection in an intragastric model. Both intraperitoneal and intragastric administration of a single dose of NK5 lower than 2 ؋ 10 8 PFU at 30 min after K. pneumoniae infection was able to protect mice from death in a dose-dependent manner, but the efficacy achieved with a low dose of NK5 by intragastric treatment provided the more significant protection. Phage NK5 administered as late as 24 h after K. pneumoniae inoculation was still protective, while intraperitoneal treatment with phage was more efficient than intragastric treatment as a result of the dissemination of bacteria into the circulation at 24 h postinfection. Surveys of bacterial counts for mice treated with NK5 by the intraperitoneal route revealed that the bacteria were eliminated effectively from both blood and liver tissue. K. pneumoniae-induced liver injury, such as liver necrosis, as well as blood levels of aspartate aminotransferase and alanine aminotransferase and inflammatory cytokine production, was significantly inhibited by NK5 treatment. These data suggest that a low dose of NK5 is a potential therapeutic agent for K. pneumoniae-induced liver infection.

IntroductionDiffuse alveolar damage (DAD) is the pathological hallmark of acute respiratory distress syndrome (ARDS), however, the presence of DAD in the clinical criteria of ARDS patients by Berlin definition is little known. This study is designed to investigate the role of DAD in ARDS patients who underwent open lung biopsy.MethodsWe retrospectively reviewed all ARDS patients who met the Berlin definition and underwent open lung biopsy from January 1999 to January 2014 in a referred medical center. DAD is characterized by hyaline membrane formation, lung edema, inflammation, hemorrhage and alveolar epithelial cell injury. Clinical data including baseline characteristics, severity of ARDS, clinical and pathological diagnoses, and survival outcomes were analyzed.ResultsA total of 1838 patients with ARDS were identified and open lung biopsies were performed on 101 patients (5.5 %) during the study period. Of these 101 patients, the severity of ARDS on diagnosis was mild of 16.8 %, moderate of 56.5 % and severe of 26.7 %. The hospital mortality rate was not significant difference between the three groups (64.7 % vs 61.4 % vs 55.6 %, p = 0.81). Of the 101 clinical ARDS patients with open lung biopsies, 56.4 % (57/101) patients had DAD according to biopsy results. The proportion of DAD were 76.5 % (13/17) in mild, 56.1 % (32/57) in moderate and 44.4 % (12/27) in severe ARDS and there is no significant difference between the three groups (p = 0.113). Pathological findings of DAD patients had a higher hospital mortality rate than non-DAD patients (71.9 % vs 45.5 %, p = 0.007). Pathological findings of DAD (odds ratio: 3.554, 95 % CI, 1.385–9.12; p = 0.008) and Sequential Organ Failure Assessment score on the biopsy day (odds ratio: 1.424, 95 % CI, 1.187–1.707; p<0.001) were significantly and independently associated with hospital mortality. The baseline demographics and clinical characteristics were not significantly different between DAD and non-DAD patients.ConclusionsThe correlation of pathological findings of DAD and ARDS diagnosed by Berlin definition is modest. A pathological finding of DAD in ARDS patients is associated with hospital mortality and there are no clinical characteristics that could identify DAD patients before open lung biopsy.

Escherichia coli is capable of synthesizing the apo-glucose dehydrogenase enzyme (GDH) but not the cofactor pyrroloquinoline quinone (PQQ), which is essential for formation of the holoenzyme. Therefore, in the absence of exogenous PQQ, E. coli does not produce gluconic acid. Evidence is presented to show that the expression of an Erwinia herbicola gene in E. coli HB101(pMCG898) resulted in the production of gluconic acid, which, in turn, implied PQQ biosynthesis. Transposon mutagenesis showed that the essential gene or locus was within a 1.8-kb region of a 4.5-kb insert of the plasmid pMCG898. This 1. (J. Bacteriol. 171:447-455, 1989). In minicell analysis, pMCG898 encoded a protein with an Mr of 41,000. These data indicate that E. coli HB101 (pMCG898) produced the GDH-PQQ holoenzyme, which, in turn, catalyzed the oxidation of glucose to gluconic acid in the periplasmic space. As a result of the gluconic acid production, E. coli HB101(pMCG898) showed an enhanced mineral phosphate-solubilizing phenotype due to acid dissolution of the hydroxyapatite substrate.Quinoproteins play a major role in the regulation of bioenergetic processes in many gram-negative bacteria, including Erwinia spp. (2). For many species of Erwinia, the nonphosphorylating oxidation pathway is the primary mechanism for aldose sugar utilization (2). The quinoprotein glucose dehydrogenase (GDH) controls the unique step in this metabolic pathway. As such, GDH plays a direct role in the generation of the transmembrane proton motive force via the oxidation of aldose sugars (5). It is now generally accepted that, in gram-negative bacteria, the membranebound quinoprotein GDH is present on the periplasmic side of the cytoplasmic membrane. GDH is a member of the largest group of quinoproteins, those that use the cofactor 2,7,9-tricarboxyl-lH-pyrrolo[2,3-flquinoline-4,5-dione (PQQ) (5).Escherichia coli does not synthesize PQQ, but it does synthesize apo-GDH and is therefore dependent on uptake of PQQ from the environment or culture medium (9). Binding of the cofactor is presumably simplified by the location of the apoenzyme on the outer face of the cytoplasmic membrane. The GDH holoenzyme may be formed in E. coli when functional genes for PQQ biosynthesis are introduced. This system has been elegantly exploited by Goosen et al. (9) in order to identify and isolate PQQ synthase genes from Acinetobacter calcoaceticus on the basis of their expression on plasmids cloned into E. coli. The expression of PQQ * Corresponding authors.synthase genes in E. coli resulted in GDH activity in the absence of exogenous PQQ. We have used a slight modification of this system to identify a PQQ synthase gene from Erwinia herbicola EHO10 (18). Our experimental approach included a unique phenotypic screening system based on our interest in elucidation of the metabolic basis for the mineral phosphate solubilization (Mps+) phenotype in gram-negative bacteria.Poorly soluble mineral phosphates such as hydroxyapatite (HAP) are dissolved via acidification (7,8). The bacterial ...

Abstract-Currently the network simulator 2 (ns-2) is a popular and powerful simulation for IEEE 802.11 wireless networks, including wireless LANs, mobile ad hoc networks (MANETs), and sensor networks. However, the network module has not been extended to IEEE 802.16 broadband wireless access networks (BWANs) or WiMAX yet. In this paper, we design and implement a new medium access control (MAC) protocol based on the IEEE 802.16 standard with the point-to-multipoint (PMP) mode for the ns-2. This module will benefit academic researchers and industrial developers in developing the WiMAX system. Besides, the architecture of the module is also presented in this paper.

IntroductionContinuous ambulatory peritoneal dialysis (CAPD) peritonitis may develop after endoscopic procedures, and the benefit of prophylactic antibiotics is unclear. In the present study, we investigated whether prophylactic antibiotics reduce the incidence of peritonitis in these patients.Patients and methodsWe retrospectively reviewed all endoscopic procedures, including esophagogastroduodenoscopy (EGD), colonoscopy, sigmoidoscopy, cystoscopy, hysteroscopy, and hysteroscopy-assisted intrauterine device (IUD) implantation/removal, performed in CAPD patients at Chang Gung Memorial Hospital, Taiwan, between February 2001 and February 2012.ResultsFour hundred and thirty-three patients were enrolled, and 125 endoscopies were performed in 45 patients. Eight (6.4%) peritonitis episodes developed after the examination. Antibiotics were used in 26 procedures, and none of the patients had peritonitis (0% vs. 8.1% without antibiotic use; p = 0.20). The peritonitis rate was significantly higher in the non-EGD group than in the EGD group (15.9% [7/44] vs. 1.2% [1/81]; p<0.005). Antibiotic use prior to non-EGD examinations significantly reduced the endoscopy-associated peritonitis rate compared to that without antibiotic use (0% [0/16] vs. 25% [7/28]; p<0.05). Peritonitis only occurred if invasive procedures were performed, such as biopsy, polypectomy, or IUD implantation, (noninvasive procedures, 0% [0/20] vs. invasive procedures, 30.4% [7/23]; p<0.05). No peritonitis was noted if antibiotics were used prior to examination with invasive procedures (0% [0/10] vs. 53.8% [7/13] without antibiotic use; p<0.05). Although not statistically significant, antibiotics may play a role in preventing gynecologic procedure-related peritonitis (antibiotics, 0% [0/4] vs. no antibiotics, 55.6% [5/9]; p = 0.10).ConclusionAntibiotic prophylaxis significantly reduced endoscopy-associated PD peritonitis in the non-EGD group. Endoscopically assisted invasive procedures, such as biopsy, polypectomy, IUD implantation/removal, and dilatation and curettage (D&C), pose a high risk for peritonitis. Prophylactic antibiotics for peritonitis prevention may be required in colonoscopic procedures and gynecologic procedures.