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Activation of hepatitis B virus S promoter by the viral large surface protein via induction of stress in the endoplasmic reticulum.

Hepatitis B virus (HBV) codes for three forms of surface protein. The minor, large form is translated from transcripts specified by the preS1 promoter, while the middle and small forms are translated from transcripts specified by the downstream S promoter. When the large surface protein is overexpressed, the secretion of both subviral and virion particles is blocked within the secretory pathway. We show here that overexpression of the large surface protein leads to up to a 10-fold activation of the S promoter but not of an unrelated promoter. Neither the middle nor the small surface protein, n

Human hepatitis B virus enhancer 1 is responsive to human interleukin-6.

Serum levels of interleukin-6 (IL-6) are elevated in acute and chronic hepatitis B patients. The effect of IL-6 and its transcription factor of NF-IL6 (a nuclear factor for IL-6) on hepatitis B virus (HBV) enhancer 1 (Enh1), which controls HBV X expression, were investigated in HepG2 cells. Twenty ng/ml of IL-6 increased 4-fold the enhancer activity of Enh1 according to the CAT assay. The IL-6 stimulation was abolished by introducing a mutation either in an AP-1-related site or a C-stretch sequence in the Enh1 sequence, demonstrating that the cis-elements are necessary for the IL-6 response. C

Three essential promoter elements mediate tumour necrosis factor and interleukin-1 activation of the granulocyte-colony stimulating factor gene.

Granulocyte-colony stimulating factor (G-CSF) is a haemopoietic growth factor produced by mesenchymal cells but not T lymphocytes after stimulation with specific cytokines or mitogens. A 330 bp promoter fragment of the human G-CSF gene induced reporter gene expression in human embryonic lung fibroblasts in response to tumor necrosis factor-alpha (TNF-alpha) or interleukin-1 beta (IL-1 beta). The same promoter fragment was not active in Jurkat T cells nor did it respond to phorbol ester in either cell type. At least three distinct elements, the CK-1 sequence, a decanucleotide present in haemopo

Burkholderia pseudomallei: the unbeatable foe?

Although melioidosis has been recognized in Thailand for many years and considerable progress in term of diagnosis and treatment was achieve … d septicemic melioidosis used to occur in 82-87% of the patients who were treated with doxycycline, chloramphenicol, cotrimoxazole and kanamycin and in non-disseminated septicemic melioidosis about 20%. With ceftazidime therapy, the mortality rate was cut by half to 35-40%. About 50% of the patients deteriorated rapidly and died within the first few days of fever …

First Report of Phyllosticta capitalensis causing leaf spot on Eriobotrya japonica in China.

Loquat (Eriobotrya japonica), a member of the Rosaceae family that has been widely grown in South China, is rich in triterpenoids and has nu … times in sterile water, dried on sterilized paper, placed on potato dextrose agar (PDA) containing chloramphenicol (100 mg/L), and incubated at 25°C for 7 days (16 h light, 8 h dark). Five morphologically identical isolates were obtained. Fungal colonies were greyish-green with a granular surface and white wavy edges, and the colony reverse turned black over tim …

First Report of the root rot of Ardisia crenate caused by Neofusicoccum parvum in China.

Ardisia crenata Sims, belonging to the family Myrsinaceae, has high medicinal and economic value. In July 2021, root rot disease was observe … washed three times with sterile water, and incubated on potato dextrose agar (containing 10μg/mL of chloramphenicol) for five days at 28°C. The hyphal tip technique (Senanayake et al. 2020) was used to obtain pure cultures. Sixteen strains exhibiting similar morphological characteristics were isolated from the infected tissues. The colonies of these isolated cult …

Analysis of Microbiological and Clinical Characteristics of Bacterial Infection in Patients with Pulmonary Infection.

OBJECTIVE: Using data investigation, the microbiology of bacterial infection in patients with pulmonary infection was discussed, and its cli … ing Stenotrophomonas maltophilia, the drug resistance rates were 79.55% for ceftazidime, 38.64% for chloramphenicol, and 31.82% for levofloxacin. Regarding Serratia marcescens, the drug resistance rates from high to low were 74.42% for cefotaxime, 72.09% for moxifloxacin, and 69.77% for gentamicin. Regarding Staphylococcus aureus in elderly patients with pulmonar …

Characterization of the multidrug efflux transporter styMdtM from Salmonella enterica serovar Typhi.

Salmonellae are foodborne pathogens and the major cause of gastroenteritis in humans. Salmonellae express multidrug efflux transporters that play a key role in their drug resistance, which is becoming an increasing problem for therapeutic intervention. Despite their biomedical importance, the mechanisms underlying substrate transport by multidrug efflux transporters remain poorly understood. Here, we describe the first characterization of a multidrug transporter belonging to the major facilitator superfamily from the genus Salmonella. We show that several clinical Salmonella Typhi (S. Typhi) i

Transforming growth factor-beta enhances the ultraviolet-mediated stress response in p53-/- keratinocytes.

Skin cancer is the most common tumor type in Caucasians, with an incidence that approaches the lifetime risk for all other cancer subtypes combined. The most common predisposing factor in the development of non-melanoma skin cancer is exposure to ultraviolet (UV) radiation in sun-light. UV radiation activates c-Jun amino-terminal kinases (JNK); this kinase pathway is involved in UV-mediated apoptosis and phosphorylation of c-Jun, all of which are part of the cellular stress response. Transforming growth factor-beta1 (TGF-beta1) is an important negative regulator of keratinocyte proliferation a

Dominant negative mutants of human T-cell leukemia virus type I Rex and human immunodeficiency virus type 1 Rev fail to multimerize in vivo.

Human T-cell leukemia virus type I (HTLV-I) Rex and human immunodeficiency virus type 1 (HIV-1) Rev are essential gene products required for the replication of these two pathogenic human retroviruses. Both Rex and Rev act at a posttranscriptional level by binding to highly structured RNA-response elements, the Rex-response element in HTLV-I and the Rev-response element in HIV-1. Using a sensitive in vivo assay of protein-protein interaction, we now demonstrate that the HTLV-I Rex and HIV-1 Rev proteins readily form homomultimeric complexes in the absence of their cognate RNA-response elements

Regulation of JC virus expression in B lymphocytes.

The etiologic agent of progressive multifocal leukoencephalopathy, a subacute demyelinating disease of the central nervous system, is the human polyomavirus JC virus (JCV), which causes a lytic infection of myelin-producing oligodendrocytes. In infected individuals the JCV genome can be detected in brain tissue and B lymphocytes isolated from the blood, bone marrow, or lymph nodes. Using mobility shift assays and a radiolabeled oligonucleotide from the JCV promoter-enhancer region (JCV bp 130 to 160), referred to as domain B, we were able to detect specific bands of the same mobility in nuclea

A conserved C-terminal sequence that is deleted in v-ErbA is essential for the biological activities of c-ErbA (the thyroid hormone receptor).

The thyroid hormone (T3) receptor type alpha, the c-ErbA alpha proto-oncoprotein, stimulates transcription of T3-dependent promoters, interferes with AP-1 activity, and induces erythroid differentiation in a ligand-dependent manner. The v-ErbA oncoprotein does not bind hormone and has lost all of these activities. Using c-ErbA/v-ErbA chimeras, we found that a deletion of 9 amino acids, conserved among many members of the nuclear receptor superfamily, which are located at the extreme carboxy terminus of c-ErbA alpha is responsible for loss of both transactivation and transcriptional interferenc

Activation of the GM-CSF promoter by HTLV-I and -II tax proteins.

Production of granulocyte-macrophage colony-stimulating factor (GM-CSF) by normal T lymphocytes requires activation by antigen, mitogen or lectin, whereas T-cell lines transformed by human T-cell leukemia virus type I (HTLV-I) or type II (HTLV-II) constitutively produce high levels of GM-CSF. Using transient cotransfection assays, we demonstrate that introduction of the tax gene of either HTLV-I or HTLV-II is sufficient to activate GM-CSF promoter constructs in an unstimulated T-cell line. The GM-CSF 5' flanking sequences previously shown to be sufficient for GM-CSF induction following T-cell

[Simultaneous determination of 30 antibiotics in soil by ultra-high performance liquid chromatography-tandem mass spectrometry].

The complexity of the soil matrix, as well as the wide spectrum and trace levels of antibiotic residues in soil, make highly sensitive instr … ams, amphenicols, and lincosamides) in soil samples. In the UHPLC-MS/MS experiment, florfenicol and chloramphenicol were analyzed in the negative ionization multiple-reaction monitoring (MRM) mode, and the other 28 target analytes were analyzed in the positive MRM mode. Sensitive MS conditions were realized by optimizing the instrumental parameters such as collis …

Unraveling the Anti-Cancer Mechanisms of Antibiotics: Current Insights, Controversies, and Future Perspectives.

Cancer persists as a significant global health challenge, claiming millions of lives annually despite remarkable strides in therapeutic innovation. Challenges such as drug resistance, toxicity, and suboptimal efficacy underscore the need for novel treatment paradigms. In this context, the repurposing of antibiotics as anti-cancer agents has emerged as an attractive prospect for investigation. Diverse classes of antibiotics have exhibited promising anti-cancer properties in both in vitro and in vivo studies. These mechanisms include the induction of apoptosis and cell cycle arrest, generation o

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… For instance, chloramphenicol, an older antibiotic that inhibits protein synthesis by binding to the 70S ribosome, has been repeatedly linked to carcinogenesis and cancer progression. … Other studies have associated chloramphenicol-induced mitochondrial stress with p21 activation and the prevention of apoptosis. These findings raise potential concerns about other classes of antibiotics that similarly affect mitochondrial function [ 131 , 132 , 133 ]. …

Aspirin inhibits tumor cell invasiveness induced by Epstein-Barr virus latent membrane protein 1 through suppression of matrix metalloproteinase-9 expression.

Matrix metalloproteinases (MMPs) are thought to play crucial roles in tumor invasion and metastasis. Because we have shown that EBV latent membrane protein 1 (LMP1) enhances MMP-9 expression by activation of nuclear factor (NF)-kappaB and activator protein (AP)-1 (T. Yoshizaki, et al., Proc. Natl. Acad. Sci. USA, 95: 3621-3626, 1998), we therefore tested whether up-regulation of MMP-9 by LMP1 could be correlated with enhanced invasiveness of tumor cells in vitro. Whether aspirin and sodium salicylate could reduce invasiveness and whether LMP1 could enhance MMP-9 expression in tumors grown in n

Integrin signaling to NF-kappa B in monocytic leukemia cells is blocked by activated oncogenes.

Integrin-mediated signals play an important but poorly understood role in regulating the growth and behavior of tumor cells. In monocytes and monocytic leukemia cells, integrin-mediated adhesion results in a strong induction of a set of immediate early genes that are characteristic of monocytic differentiation and contain consensus NF-kappa B elements in their 5' regulatory regions. To investigate the role of integrin signaling in control of differentiation in a human monocytic leukemia cell line, THP-1 cells were transiently transfected with an NF-kappa B driven CAT reporter gene. Adhesion to

Transcriptional activity of the paired-like homeodomain proteins CHX10 and VSX1.

CHX10 and VSX1 are homeodomain (HD) proteins essential for normal retinal development. CHX10 is required first for retinal progenitor cell proliferation and later for bipolar cell differentiation, whereas VSX1 is important in the terminal differentiation of a subset of bipolar cells. Elucidating the transcriptional activity of CHX10 and VSX1 is required to understand how these factors control retinal development. We show that CHX10 and Vsx1 can function as transcriptional repressors. When tethered to a promoter by a heterologous LexA DNA-binding domain or its HD, CHX10 repressed multiple class

Mechanism of promoter activity of the beta-amyloid precursor protein gene in different cell lines: identification of a specific 30 bp fragment in the proximal promoter region.

The amyloid beta-protein (Abeta) deposited in brains of Alzheimer's disease (AD) patients is proteolytically derived from a large Abeta precursor protein (APP). APP gene expression patterns in the AD brain region indicate that abnormalities of gene regulation may be important in AD pathology. To understand the contribution of different cell types to APP gene expression, we studied it at four levels: promoter activity (by reporter gene assay of transfected cells), DNA-nuclear protein interaction (by electrophoretic mobility shift assay), RNA message and protein (by northern and western blotting