The synergistic interaction between the calcineurin B subunit and IFN-γ enhances macrophage antitumor activity

Macrophages are involved in tumor growth and progression. They infiltrate into tumors and cause inflammation, which creates a microenvironment favoring tumor growth and metastasis. However, certain stimuli may induce macrophages to act as tumor terminators. Here we report that the calcineurin B subunit (CnB) synergizes with IFN-γ to make macrophages highly cytotoxic to cancer cells. Furthermore, CnB and IFN-γ act synergistically to polarize mouse tumor-associated macrophages, as well as human monocyte-derived macrophages to an M1-like phenotype. This synergy is mediated by the crosstalk between CnB-engaged integrin αM-p38 MAPK signaling and IFN-γ-initiated p38/PKC-δ/Jak2 signaling. Interestingly, the signal transducer and activator of transcription 1 (STAT1) is a key factor that orchestrates the synergy of CnB and IFN-γ, and the phosphorylation status at Ser727 and Tyr701 of STAT1 is directly regulated by CnB and IFN-γ.

Problematic effects of antibiotics on anaerobic treatment of swine wastewater

Swine wastewaters with high levels of organic pollutants and antibiotics have become serious environmental concerns. Anaerobic technology is a feasible option for swine wastewater treatment due to its advantage in low costs and bioenergy production. However, antibiotics in swine wastewater have problematic effects on micro-organisms, and the stability and performance of anaerobic processes. Thus, this paper critically reviews impacts of antibiotics on pH, COD removal efficiencies, biogas and methane productions as well as the accumulation of volatile fatty acids (VFAs) in the anaerobic processes. Meanwhile, impacts on the structure of bacteria and methanogens in anaerobic processes are also discussed comprehensively. Furthermore, to better understand the effect of antibiotics on anaerobic processes, detailed information about antimicrobial mechanisms of antibiotics and microbial functions in anaerobic processes is also summarized. Future research on deeper knowledge of the effect of antibiotics on anaerobic processes are suggested to reduce their adverse environmental impacts.

Phosphorylase phosphatase: new horizons for an old enzyme

Protein phosphatase-1, originally studied as phosphorylase phosphatase, is one of the major ser/thr protein phosphatases. It has a long history and a complex enzymology. It consists of a catalytic subunit of 37 kDa, which is bound to a number of different regulatory or targeting subunits. These are believed to restrict its activity to its immediate microenvironment and thus define its specificity, as well as acting to regulate phosphatase activity. The existence of multiple protein phosphatase-1 binding proteins provides the mechanism whereby phosphatase-1 activity can be involved in a diverse range of cellular functions, and reflects a novel strategy for its evolutionary development.

DNA repair in lymphoblastoid cell lines from patients with head and neck cancer

OBJECTIVE

To analyze and compare components of the 3 primary DNA repair pathways of Epstein-Barr virus-transformed lymphocyte (lymphoblastoid) cell lines derived from 9 patients with squamous cell carcinoma of the head and neck and 11 cancer-free controls. These cell lines were previously characterized by using an established cytogenetic marker of cancer susceptibility (mutagen sensitivity assay).

DESIGN

To evaluate nucleotide excision repair (NER), we measured the reactivation level of a tobacco carcinogen-damaged plasmid containing a bacterial reporter gene transfected into these cells. To assess mismatch repair (MMR) and recombinational repair, selected gene transcript levels were quantified by using a multiplex reverse transcriptase-polymerase chain reaction assay. The results of these DNA repair assays were correlated with the previously measured mutagen sensitivity values.

RESULTS

The NER capacities of the 2 groups were similar: 25.1% (range, 14.3%-33.3%) for the patient cell lines and 26.0% (range, 9.4%-47.7%) for the control lines. Transcriptase levels for 6 MMR genes (hMSH3, hMSH2, hPMS2, GTBP, hMLH1 and hPMS1) did not differ in the 2 groups. Transcript levels for 4 of 6 recombinational repair genes (XRCC7, XRCC6, XRCC1, and RAD51) were higher in the patient cell lines, though this difference was significant only for XRCC7 (P = .003). The mutagen sensitivity values correlated with the NER capacity (P = .05) and the expression of XRCC4 (P = .01) and RAD51 (P = .06) genes.

CONCLUSIONS

As revealed by the above-named assays, these lymphoblastoid cell lines derived from patients with head and neck cancer had minor alterations in DNA repair function. However, these differences in DNA repair do appear to affect the cytogenetic marker of cancer susceptibility, mutagen sensitivity.

Direct correlation between DNA repair capacity and metastatic potential of K-1735 murine melanoma cells

The purpose of this study was to determine whether the ability of K-1735 murine melanoma cells to repair DNA damage correlates with their metastatic potential. Three nonmetastatic clones, four metastatic clones, and three somatic-cell hybrids between metastatic and nonmetastatic clones were exposed to incident ultraviolet (UV) light (254 nm). Cell survival was determined by the microculture tetrazolium assay, which measures cell metabolic activity. DNA repair capacity was determined with a host-cell reactivation assay, which measures the activities of chloramphenicol acetyltransferase encoded by the reporter gene in both UV-damaged and undamaged plasmid (control) pCMV cat 40 h after transfection. No discernible differences in transfection efficiencies were found between K-1735 clones with low and high metastatic potential or between cells transfected with UV-damaged and control plasmids. DNA repair capacity directly correlated with cell survival (p < 0.05) and with metastatic potential in the K-1735 clones and somatic cell hybrids (p < 0.05). These data suggest that the intrinsic resistance of melanoma metastases to systemic chemotherapy may be due, in part, to the cells' enhanced DNA repair capacity.

The C-truncated delta-opioid receptor underwent agonist-dependent activation and desensitization

The agonist-dependent activation and desensitization of a recombinant analog of delta-opioid receptor lacking the carboxyl-terminal (C-terminal) 31 residue peptide segment were discussed. The cDNA of the C-truncated delta-opioid receptor was created by polymerase chain reaction (PCR), stably expressed in Chinese hamster ovary cells and characterized by binding assay and function assay. Agonist [D-Pen2, D-Pen5]-enkephalin (DPDPE) stimulated the specific [35S]GTPgammaS binding to membrane fragments of cells expressing the C-truncated and the wild-type delta-opioid receptors in different levels dose-dependently. EC50 values of DPDPE on truncated and wild-types in stimulation were very similar. Agonist-dependent desensitization, which could be blocked by protein kinase inhibitor staurosporine (Stau), was observed after pretreating truncated receptors with 1 microM DPDPE for 10 min, the same as wild-types. The results reveal that the C-terminal of the delta-opioid receptor is not involved in controlling the G-protein activation and phosphorylation-related functional desensitization.

Analysis of TP53 mutations in relapsed childhood acute lymphoblastic leukemia

TP53 is the most commonly mutated gene in human cancer, but TP53 mutations are present in less than 5% of children with acute lymphoblastic leukemia (ALL) at initial presentation. Mutations are detected more frequently in children with relapsed T-cell ALL, but the potential role of TP53 mutations in relapsed B-lineage childhood ALL is not understood as well. The authors determined the nucleotide sequence of amplified DNA from exons 5 to 8 of the TP53 gene in leukemic cells obtained from 17 children with ALL at the time of first bone marrow relapse. All 17 contained only germline TP53 sequences. Review of the published literature disclosed that TP53 mutations have been found in 22% of cases of relapsed ALL. To understand the role of p53 abnormalities in this clinical setting, it will be important for future studies to analyze cases of relapsed ALL with assays capable of interrogating the functional integrity of the p53 pathway.

Tendencies for higher co-expression of EGFR and HER2 and downregulation of HER3 in prostate cancer lymph node metastases compared with corresponding primary tumors

The epidermal growth factor receptor (EGFR) family members are potential targets for therapy using extra-cellular domain receptor binding agents, such as the antibodies trastuzumab and cetuximab, or antibodies labeled with therapeutically useful radionuclides or toxins. This is especially the case when the tumor cells are resistant to chemotherapy and tyrosine kinase inhibitors. Studies concerning the expression of these receptors in prostate cancer vary in the literature, possibly due to differences in patient inclusion, sample preparations and scoring criteria. In our study, EGFR, HER2 and HER3 expression was analyzed in prostate cancer samples from primary tumors and corresponding lymph node metastases from 12 patients. The expression of HER2 and EGFR was scored from immunohistochemical preparations and the HercepTest criteria (0, 1+, 2+ or 3+), while HER3 expression was scored as no, weak or strong staining. There were 5 EGFR-positive (2+ or 3+) primary tumors and 6 EGFR-positive lymph node metastases, and there was EGFR upregulation in one metastasis. Only 4 of the 12 patients had marked HER2 expression (2+ or 3+) in their primary tumors and there was one downregulation and 5 cases of upregulation in the metastases. Thus, a total of 8 out of 12 analyzed metastases were HER2-positive. Of the 12 primary tumors, 9 expressed HER3 while only 2 of the lymph node metastases expressed recognizable HER3 staining, so 7 metastases appeared to have downregulated HER3 expression. In one of the primary tumors there was positive co-expression of EGFR and HER2, while this co-expression was observed in 4 of the metastases. Thus, there were tendencies for upregulation of HER2, increased co-expression of EGFR and HER2 and downregulation of HER3 in the prostate cancer lymph node metastases in comparison to the primary tumors. The results are encouraging for studies involving more patients. Possible strategies for EGFR- and HER2-targeted therapy are briefly discussed in the present study, especially with regard to the expression and co-expression of EGFR and HER2 in metastases.

Strong strain hardening in nanocrystalline nickel

Low strain hardening has hitherto been considered an intrinsic behavior for most nanocrystalline (NC) metals, due to their perceived inability to accumulate dislocations. In this Letter, we show strong strain hardening in NC nickel with a grain size of approximately 20 nm under large plastic strains. Contrary to common belief, we have observed significant dislocation accumulation in the grain interior. This is enabled primarily by Lomer-Cottrell locks, which pin the lock-forming dislocations and obstruct dislocation motion. These observations may help with developing strong and ductile NC metals and alloys.

High activity of the calcineurin A subunit with a V314 deletion

A deletion mutant (V314) of the calcineurin A subunit was constructed using site-directed mutagenesis. Its phosphatase activity and function were then characterized. The V314 deletion significantly altered the phosphatase activity, which was more than ten times higher than that of wild-type calcineurin, the calcineurin-immunosuppressant/immunophilin interaction, the effect of metal ions and calcineurin subunit interaction. We propose that the change of the activity and function of V314 is due to conformational changes of calcineurin to benefit the binding of, or stimulation by, Mn2+, or to affect the interaction between the A and B subunits.

E-box- and MEF-2-independent muscle-specific expression, positive autoregulation, and cross-activation of the chicken MyoD (CMD1) promoter reveal an indirect regulatory pathway

Members of the MyoD family of gene-regulatory proteins (MyoD, myogenin, myf5, and MRF4) have all been shown not only to regulate the transcription of numerous muscle-specific genes but also to positively autoregulate and cross activate each other's transcription. In the case of muscle-specific genes, this transcriptional regulation can often be correlated with the presence of a DNA consensus in the regulatory region CANNTG, known as an E box. Little is known about the regulatory interactions of the myogenic factors themselves; however, these interactions are thought to be important for the activation and maintenance of the muscle phenotype. We have identified the minimal region in the chicken MyoD (CMD1) promoter necessary for muscle-specific transcription in primary cultures of embryonic chicken skeletal muscle. The CMD1 promoter is silent in primary chick fibroblast cultures and in muscle cell cultures treated with the thymidine analog bromodeoxyuridine. However, CMD1 and chicken myogenin, as well as, to a lesser degree, chicken Myf5 and MRF4, expressed in trans can activate transcription from the minimal CMD1 promoter in these primary fibroblast cultures. Here we show that the CMD1 promoter contains numerous E-box binding sites for CMD1 and the other myogenic factors, as well as a MEF-2 binding site. Surprisingly, neither muscle-specific and the other myogenic factors, as well as a MEF-2 binding site. Surprisingly, neither muscle-specific expression, autoregulation, or cross activation depends upon the presence of of these E-box or MEF-2 binding sites in the CMD1 promoter. These results demonstrate that the autoregulation and cross activation of the chicken MyoD promoter through the putative direct binding of the myogenic basic helix-loop-helix regulatory factors is mediated through an indirect pathway that involves unidentified regulatory elements and/or ancillary factors.

Reduced expression of hMSH2 and hMLH1 and risk of prostate cancer: a case-control study

BACKGROUND

Although prostate cancer is the most common incident cancer in men, not much is known about its etiology. We tested the hypothesis that expression levels of hMSH2 and hMLH1 in unaffected (normal) tissue play a role in the etiology of prostate cancer.

METHODS

Total RNA was extracted from peripheral blood lymphocytes of subjects ascertained by a case-control study (70 patients and 97 age- and ethnicity-matched controls). A multiplex reverse transcription-polymerase chain reaction assay was used to simultaneously evaluate the relative expression of hMSH2 and hMLH1, using beta-actin as the internal control.

RESULTS

The relative gene expression levels of hMSH2 and hMLH1 were significantly lower in cases than in controls (P < 0.05 for both genes). When compared with the highest tertile of the controls, low expression levels (the middle and lowest tertiles) of hMLH1 were associated with significantly increased risk of prostate cancer in a dose-response relationship (ORs = 2.68, and 4.31; 95% confidence interval = 1.00-7.23 and 1.64-11.30, respectively) after adjustment for age, ethnicity, smoking status, and family history of prostate cancer.

CONCLUSIONS

These results suggest that reduced expression of hMLH1 in peripheral lymphocytes may be a risk factor for prostate cancer. However, it cannot be ruled out that the reduced expression we observed may be caused by the disease status. Our findings and the factors that may affect the expression of hMLH1 need further confirmation in larger prospective studies.

Construction and evaluation of fibrillar composite hydrogel of collagen/konjac glucomannan for potential biomedical applications

Konjac glucomannan (KGM) is recognized as a safe material for its health-promoting benefits and thus widely used in various fields including pharmaceutical industry. In recent decades, the combination of collagen and KGM attracts more attentions for biomedical purpose, especially the hybrid films of collagen–KGM or collagen–KGM–polysaccharide. In this study, to further and deeply develop the intrinsic values of both collagen and KGM as biomaterials, a novel kind of composite hydrogel comprising collagen and KGM at a certain ratio was fabricated under mild conditions via fibrillogenesis process of the aqueous blends of collagen and KGM that experienced deacetylation simultaneously. The chemical composition, microcosmic architectures, swelling behavior, biodegradation and dynamic mechanic properties of such resulted composite hydrogels were systematically investigated. Biologic experiments, including cell culture in vitro and hypodermic implantation in vivo, were also conducted on these collagen/KGM composite hydrogels to evaluate their biologic performances. The relevant results prove that, based on collagen self-assembly behavior, this synthesis strategy is efficient to construct a composite hydrogel of collagen/KGM with improved mechanical properties, biodegradability, excellent biocompatibility and bioactivity, which are promising for potential biomedical applications such as tissue engineering and regenerative medicine.

Proanthocyanidin-crosslinked collagen/konjac glucomannan hydrogel with improved mechanical properties and MRI trackable biodegradation for potential tissue engineering scaffolds

Collagen (Col) has been intensively exploited as a biomaterial for its excellent biocompatibility, biodegradation and bioactivity. However, the poor mechanical properties and rapid biodegradation of reconstituted collagen hydrogels have always been the bottlenecks for their further development especially for vascular tissue engineering. Herein, based on the self-assembly characteristics of collagen, a ternary hydrogel scaffold, comprising rigid collagen molecules, flexible konjac glucomannan (KGM) chains and biocompatible crosslinkers of proanthocyanidin (PA), has been designed to achieve a synergistic interaction for essentially optimizing the mechanical properties of the so-obtained Col/KGM/PA hydrogel, which possesses not only substantially improved strength but also good elasticity. PA endows these scaffolds with controllable biodegradation and anti-calcification and antioxidant activities. TEM discovered the co-existence of two types of fibrils with distinctly different arrangement patterns, explaining the contribution of KGM macromolecules to elasticity generation. The in vivo variations of Col/KGM/PA implants are visualized in real-time by magnetic resonance imaging (MRI). Moreover, a quantitative technique of MRI T₂-mapping combined with histology is designed to visualize the in vivo biodegradation mechanism of layer-by-layer erosion for these hydrogels. Simultaneously, three different relationships between the respective processes of in vivo degradation and in vivo dehydration of these controlled hydrogel implants were clearly revealed by this technique. Such a designed Col/KGM/PA composite hydrogel realizes the essential integration of good biocompatibility, controllable biodegradation and improved mechanical properties for developing a desired scaffold material for tissue engineering applications.

A Polymerase Chain Reaction Protocol for the Detection of Clavibacter xyli subsp. xyli, the Causal Bacterium of Sugarcane Ratoon Stunting Disease

A polymerase chain reaction (PCR) protocol was developed that specifically detected Clavibacter xyli subsp. xyli, the causal agent of sugarcane ratoon stunting disease. Generic PCR products from the intergenic transcribed spacer (ITS) region of 16S-23S ribosomal DNA of C. xyli subsp. xyli and C. xyli subsp. cynodontis were cloned and sequenced. Based on a multiple sequence alignment among these two sequences and other nonredundant highly homologous sequences from the database, two C. xyli subsp. xyli-specific PCR primers were designed, Cxx1 (5' CCGAAGTGAGCAGATTGACC) and Cxx2 (5' ACCCTGTGTTGTTTTCAACG). These two 20-mer oligonucleotides primed the specific amplification of a 438-bp DNA product from genomic DNA samples of 21 C. xyli subsp. xyli strains. Amplification was not observed with genomic DNA of one C. xyli subsp. cynodontis strain, five strains of four other Clavibacter species, and two strains of two Rathayibacter species. The 438-bp PCR product also was amplified directly from cultured C. xyli subsp. xyli cells and from C. xyli subsp. xyli-infected sugarcane vascular sap with a unique reaction buffer containing polyvinylpyrrolidone and ficoll. Extraction of genomic DNA was not necessary prior to PCR assay.

Synthesis of Single Crystal Bismuth-Telluride and Lead-Telluride Nanowires for New Thermoelectric Materials

Dimensionality can play an important role in determining the properties of materials. In the case of thermoelectric materials, it has been proposed that one-dimensional quantum wires, or nanowires, and two-dimensional superlattices could exhibit substantially higher efficiencies compared to the corresponding bulk, three-dimensional solids. To explore such predictions we have initiated a program directed towards the controlled growth of nanowires, and herein, we report the synthesis of single crystal Bi2Te3 and PbTe nanowires by a pulsed laser ablation method. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) show that Bi2Te3 wires 80 nm to 200 nm in diameter and lengths exceeding 10 microns, and PbTe wires 25 nm to 60 nm in diameter and lengths to 2 microns can be readily produced by the laser ablation method. High-resolution TEM and electron diffraction show that Bi2Te3 nanowires are single crystals with wire axes along the <110> crystal direction. TEM and electron diffraction measurements also show that the PbTe nanowires are single crystals with a <100> growth axis. The transport properties of these new nanowire materials will be discussed.