A metabolic-activity-detecting approach to life detection: Restoring a chemostat from stop-feeding using a rapid bioactivity assay.

A mediated glassy carbon electrode covered by a thin-film polyviologen was used in the present study to rapidly detect bioactivity in a mixed-culture chemostat (dominated by Clostridium sp.). With the addition of 1mM hexacyanoferrate and 9mM glucose, the current increasing rate (dI/dt) measured under a poised potential of 500mV (vs. Ag/AgCl) can be defined as the quantity of metabolic activity. In the experiment of restoring the chemostat from stop-feeding, it is suggested that when the dI/dt was >2µAmin-1, the influent pump could be directly turned on to maintain the high dilution rate of 0.5h-1; when the dI/dt was lower than 2µAmin-1, reducing the dilution rate would be needed to avoid cell wash out. Since the soluble mediators and polyviologen film will enhance performances by favorable electron transfer and positively charged surfaces, respectively, we suggest that the method can also be employed to detect the bioactivities in environmental samples.

Serum BAFF and thyroid autoantibodies in autoimmune thyroid disease.

BACKGROUND: This study investigated the association of serum B-lymphocyte activating factor (BAFF) levels with autoimmune thyroid disease (AITD) in a Chinese population. MATERIALS AND METHODS: We enrolled 221 patients with AITD [170 patients with Graves' disease (GD), 51 patients with Hashimoto's thyroiditis (HT)], and 124 healthy controls. Serum BAFF levels, thyroid function and thyroid autoantibody (TAb) levels, including of thyroid-stimulating hormone receptor antibody (TSHRAb), anti-thyroid peroxidase antibody (Anti-TPO Ab), and antithyroglobulin antibody (ATA), were measured at baseline. RESULTS: Serum BAFF levels were higher in the GD, HT, and AITD groups than in the control group. Significant correlations were observed between BAFF and TSHRAb levels (r=0.238, p=0.018), between BAFF and Anti-TPO Ab levels (p=0.038), and between BAFF and ATA titers (p=0.025) in women but not in men. In addition, serum BAFF levels were significantly associated with free thyroxine (r=0.430, p=0.004) and TSHRAb (r=0.495, p=0.001) levels in women with active GD but not in those with inactive GD. CONCLUSIONS: Serum BAFF levels are increased in GD, HT, and AITD. The correlation between serum BAFF and TAb levels exhibits a dimorphic pattern, particularly in active GD.

Annexin A2 in renal cell carcinoma: expression, function, and prognostic significance.

OBJECTIVE: Renal cell carcinoma (RCC) is the most lethal genitourinary cancer and intrinsically resistant to chemotherapy, radiotherapy, and hormone therapy. Annexin A2 (Anxa2) is a calcium-dependent phospholipid-binding protein found on various cell types that plays multiple roles in regulating cellular functions. In RCC, Anxa2 expression was correlated with tumor differentiation, clinical outcomes, and the metastatic potential; however, the underlying mechanisms remain obscure. This study investigated the role of Anxa2 in regulating tumorigenesis of RCC. MATERIALS AND METHODS: Commercial RCC tissue microarray arrays and a kidney cancer quantitative polymerase chain reaction array were used to examine Anxa2 by immunohistochemistry and real-time polymerase chain reaction analysis. Short hairpin (sh)RNA-based lentiviral system technology was used to evaluate the effects of manipulating Anxa2 expression on multiple malignant features of 2 RCC cell lines, A498 and 786-O, and its mechanisms. RESULTS: (1) The Anxa2 expression level was generally elevated to varying degrees in RCC tissues. In adjacent noncancerous tissues, Anxa2 was mainly expressed in glomeruli and slightly expressed in the cytoplasm of proximal tubules. (2) An increased Anxa2 expression level was found in tissues of clear cell RCC, papillary RCC, and chromophobe RCC, and it was prominently expressed in cancer cell membranes. In addition, the Anxa2 expression level was correlated with poor prognosis. (3) Silencing Anxa2 expression suppressed the abilities of cell migration and invasion, but cell proliferation was less affected. (4) Diminished Anxa2 expression caused alterations in the cell polarity, disrupted the formation of actin filaments, and reduced CXCR4 expression. (5) Inhibition of the Rho/Rock axis restored silencing of Anxa2-mediated suppression of cell motility. CONCLUSIONS: Overall, our study points out the regulatory function of Anxa2 in RCC cell motility and provides a molecular-based mechanism of Anxa2 positivity in the progression of RCC.

Silencing glucose-regulated protein 78 induced renal cell carcinoma cell line G1 cell-cycle arrest and resistance to conventional chemotherapy.

OBJECTIVE: Glucose-regulated protein 78 (Grp78) is an endoplasmic reticulum chaperone; it maintains endoplasmic reticulum homeostasis and modulates unfolded protein response. The protein is overexpressed in various cancer types, including renal cell carcinoma (RCC). Increased Grp78 expression in patients with RCC is correlated with more aggressive tumors and poorer prognoses. This study investigated the role of Grp78 in regulating tumorigenesis and evaluated the potential of Grp78-targeted therapy for RCC. METHODS: The expression level of Grp78 was examined in von Hippel-Lindau (VHL)-intact or VHL-null RCC cell lines by reverse transcription polymerase chain reaction and Western blot. Specific Grp78 ribonucleic acid interference was applied as a molecularly Grp78-targeted therapeutic approach. This method enabled us to assess the effects of manipulating Grp78 expression to regulate RCC cell growth. RESULTS: The Grp78 messenger ribonucleic acid and protein were expressed in both VHL-intact and VHL-null RCC cell lines. The specific inhibition of Grp78 expression suppressed RCC cell growth and colony formation significantly, and induced G1 cell-cycle arrest. We also showed that inhibiting Grp78 expression increased the cells' resistance to the cytotoxicity of the S-phase-specific anticancer drug 5-fluorouracil. This effect was regulated by the unfolded protein response-induced suppression of G1/S transition-related cyclins (D1, E1, and E2) and cyclin-dependent kinase (CDK4 and CDK6) protein expression. CONCLUSION: Overall, our findings indicate the regulatory function of Grp78 in RCC cell proliferation, and provide a molecular-based mechanism of Grp78 positivity in the progression of RCC.

A dual-substrate steady-state model for biological hydrogen production in an anaerobic hydrogen fermentation process.

Biological hydrogen production from anaerobic waste fermentation possesses potential benefits in simultaneously reducing organic wastes and generating sustainable energy sources. Three kinetic-based steady-state models for anaerobic fermentation of multiple substrates, including glucose and peptone, were evaluated. Experimental results obtained from a continuous stirred tank reactor (CSTR) were primarily used for model evaluation. The dual-substrate steady-state model developed and the associated kinetic parameters estimated in this study successfully described the anaerobic growth of hydrogen-producing bacteria. The model was able to capture the general trends of consumption of substrates and accumulation of products, including formate, acetate, butyrate, and hydrogen, at dilution rates (D) between 0.06 and 0.69/h. According to the model, the adverse effects of endogeneous and peptone metabolism on net hydrogen production can be minimized by increasing D. For the operational conditions of D > 0.69/h, however, substantial washout of hydrogen-producing bacteria from the CSTR was observed, and it resulted in a rapid drop in hydrogen production rate as well.

Probing C-H...X hydrogen bonds in amide-functionalized imidazolium salts under high pressure.

We have probed under high pressure the C-H hydrogen bonds formed by N,N(')-disubstituted imidazolium ions having PF(6) (-) and Br(-) counterions. High-pressure infrared spectral profiles, x-ray crystallographic analysis, and ab initio calculations allow us to make a vibrational assignment of these compounds. The appearance of a signal for the free-NH unit (or weakly bonded N-H...F unit) in the infrared spectrum of the PF(6) (-) salt indicates that conventional N-H...O and N-H...N hydrogen bonds do not fully dominate the packing. It is likely that the charge-enhanced C(2)-H...F interactions, combined with other weak hydrogen bonds, disturb the formation of N-H hydrogen bonds in the PF(6) (-) salt. This finding is consistent with the pressure-dependent results, which reveal that the C(2)-H...F interaction is enhanced upon increasing the pressure. In contrast to the PF(6) (-) salt, the imidazolium C-H bonds of the Br(-) salt have low sensitivity to high pressure. This finding suggests that the hydrogen bonding patterns are determined by the relative hydrogen bond acceptor strengths of the Br(-) and PF(6) (-) ions.