Monocarboxylate transporter 1-mediated lactate accumulation promotes nucleus pulposus degeneration under hypoxia in a 3D multilayered nucleus pulposus degeneration model

During intervertebral disc degeneration (IVDD), due to endplate calcification, diminished oxygen and nutrient concentrations and accumulated lactate are present in the microenvironment of the nucleus pulposus (NP). The disadvantages of 3D layered culture include uneven oxygen and nutrient gradients. In the present study, to mimic the in vivo microenvironment of the NP, a 5-layered 3D culture was constructed using clinical haemostatic gelatine sponges and developed as a NP degeneration (NPD) model. Subsequently, cell distribution as well as expression of NP chondrogenic markers (type II collagen and aggrecan), glycosaminoglycan (GAG) and degeneration markers [e.g. matrix metalloproteinase (MMP) 3] were measured from the top to the bottom layer. However, in a single NP-cell-loaded disc model, the chondrogenic potency in the middle or bottom layer was higher than that in the top layer. To further study the mechanism underlying the degeneration of NP cells in this NPD model, the contribution of secreted metabolites was examined. Lactate identified in the supernatant modulated GAG accumulation and MMP3 expression. Inhibition of lactate influx by the monocarboxylate transporter (MCT)-1 inhibitor, AZD3965, reversed the effect of lactate on GAG accumulation and MMP3 expression and further improved NP cell degeneration in the NPD model. Thanks to the homogenous expression of lactate in the model, it was possible to further identified that the combination of lactate and hypoxia enhanced MMP3 expression. Taken together, multilayered cell-loaded sponges, with oxygen and nutrient gradients as well as lactate accumulation, can represent a 3D multilayered NPD model for exploring potential agents for IVDD.

Pilot-scale cooling tower to evaluate corrosion, scaling, and biofouling control strategies for cooling system makeup water

Pilot-scale cooling towers can be used to evaluate corrosion, scaling, and biofouling control strategies when using particular cooling system makeup water and particular operating conditions. To study the potential for using a number of different impaired waters as makeup water, a pilot-scale system capable of generating 27,000 kJ∕h heat load and maintaining recirculating water flow with a Reynolds number of 1.92 × 10(4) was designed to study these critical processes under conditions that are similar to full-scale systems. The pilot-scale cooling tower was equipped with an automatic makeup water control system, automatic blowdown control system, semi-automatic biocide feeding system, and corrosion, scaling, and biofouling monitoring systems. Observed operational data revealed that the major operating parameters, including temperature change (6.6 °C), cycles of concentration (N = 4.6), water flow velocity (0.66 m∕s), and air mass velocity (3660 kg∕h m(2)), were controlled quite well for an extended period of time (up to 2 months). Overall, the performance of the pilot-scale cooling towers using treated municipal wastewater was shown to be suitable to study critical processes (corrosion, scaling, biofouling) and evaluate cooling water management strategies for makeup waters of complex quality.

Cell sorting of formalin-treated pathogenic Mycobacterium paratuberculosis expressing GFP

GFP is widely used as a molecular tool for the study of microbial pathogens. However, the manipulation of these pathogenic microorganisms poses a health threat to the laboratory worker, requiring biosafety level II or III containment. Although the GFPfluorophore is tolerant toformalin, a thorough analysis of this treatment on fluorescent output in prokaryotic systems has not been described. In addition, the analysis of microorganisms expressing GFP often depends on specialized equipment, which may not be housed in biosafety level II or III laboratories. Therefore, we sought to develop a safe and effective method for manipulating the GFP-expressing pathogenic bacterium Mycobacterium avium subsp, paratuberculosis (M. paratuberculosis) utilizing a formalin treatment that would permit the analysis of GFP fluorescence without requiring stringent biosafety containment. We demonstrate that formalin-treated M. paratuberculosis expresses 50% less fluorescence than viable cells, but this reduction is still compatible with spectrofluorometry and cell sorting. Furthermore, plasmid DNA that expresses GFP can be recovered efficiently from nonviable, sorted fluorescent cells. This approach is flexible, provides an additional margin of safety for laboratory personnel, and can be easily applied to other pathogenic microorganisms expressing GFP.

Molecular identification and characterization of turkey IFN-gamma gene

The cDNAs of turkey and chicken interferon gamma (IFN-gamma) were cloned and the functional activity of turkey and chicken IFN-gamma was compared. The coding region of turkey IFN-gamma gene encodes a predicted mature protein of 145 amino acids with a molecular weight at 16.8 kDa. Compared with type I IFN, the IFN-gamma between turkey and chicken also had the same size and high degree of identity at the nucleotide (96.0%) and amino acid (96.4%) sequence. Turkey IFN-gamma was cross-reactive with chicken cells. Both turkey and chicken IFN-gamma could induce production of nitric oxide by turkey or chicken macrophages. Turkey IFN-gamma also had similar degree of sensitivity to heat and pH 2.0 as chicken IFN-gamma. The functional activity of both turkey and chicken IFN-gamma could be neutralized by a monoclonal antibody specific to chicken IFN-gamma to a similar extent. These results indicated that IFN-gamma protein was cross-reactive between turkey and chicken.