Choriocapillaris regeneration in the rabbit: a study with vascular casts

Vascular casts were made of the choriocapillaris (CC) of rabbits that received sodium iodate intravenously 6-28 days prior to examination, in order to augment studies of CC regeneration in sectioned material. Regeneration of CC was evident 6 days after administration of iodate where zones of spared CC bordered zones of atrophic CC. Venular as well as capillary sprouts created foci of regenerating CC at this border. These foci to create an extended capillary plexus similar to mature CC. The observations corroborate those obtained in sectioned material as regards the geography of the CC response and the origins of new CC during the sodium iodate retinopathy, and provide new information on the way in which CC regenerates.     

Cloning and characterization of Arabidopsis and Brassica juncea flavin-containing amine oxidases

Polyamines (PAs) are low molecular weight metabolites involved in various physiological and developmental processes in eukaryotic and prokaryotic cells. The cellular PA level is regulated in part by the action of amine oxidases (AOs) including copper diamine oxidases (DAOs) and flavoprotein polyamine oxidases (PAOs). In this study, the isolation and characterization of flavin amine oxidases (FAOs) from Brassica juncea (BJFAO) and Arabidopsis (ATFAO1) are reported that were clustered in the same group as polyamine oxidases from maize (MPAO) and barley (BPAO1) and monoamine oxidases from mammalian species. ATFAO1 was temporally and spatially regulated in Arabidopsis and showed distinct expression patterns in response to different stress treatments. To investigate the in vivo function of FAO, transgenic Arabidopsis plants expressing sense, antisense, and double-stranded BJFAO RNAs were generated and those with altered activity of FAOs were selected for further characterization. It was found that the shoot regeneration response in transgenic plants was significantly affected by the modulated PA levels corresponding to FAO activities. Tissues that originated from transgenic plants with down-regulated FAO activity were highly regenerative, while those from transgenic plants with upregulated FAO activity were poorly regenerative. The shoot regeneration capacity in these transgenic plants was related to the levels of individual PAs, suggesting that FAO affects shoot regeneration by regulating cellular PAs. Furthermore, it was found that the effect of FAO activity on shoot regeneration was exerted downstream of the Enhancer of Shoot Regeneration (ESR1) gene, which may function in a branch of the cytokinin signalling pathway.     

Proliferating cell nuclear antigen (PCNA) as a proliferative marker during embryonic and adult zebrafish hematopoiesis

We investigated the expression of proliferative cell nuclear antigen (PCNA) in zebrafish to delineate the proliferative hematopoietic component during adult and embryonic hematopoiesis. Immunostaining for PCNA and enhanced green fluorescence protein (eGFP) was performed in wild-type and fli1-eGFP (endothelial marker) and gata1-eGFP (erythroid cell marker) transgenic fish. Expression of PCNA mRNA was examined in wild-type and chordin morphant embryos. In adult zebrafish kidney, the renal tubules are surrounded by endothelial cells and it is separated into hematopoietic and excretory compartments. PCNA was expressed in hematopoietic progenitor cells but not in mature neutrophils, eosinophils or erythroid cells. Some PCNA+ cells are scattered in the hematopoietic compartment of the kidney while others are closely associated with renal tubular cells. PCNA was also expressed in spermatogonial stem cells and intestine crypts, consistent with its role in cell proliferation and DNA synthesis. In embryos, PCNA is expressed in the brain, spinal cord and intermediate cell mass (ICM) at 24 h-post fertilization. In chordin morphants, PCNA is significantly upregulated in the expanded ICM. Therefore, PCNA can be used to mark cell proliferation in zebrafish hematopoietic tissues and to identify a population of progenitor cells whose significance would have to be further investigated.     

c-FLIP Protects Eosinophils from TNF-α-Mediated Cell Death In Vivo

Understanding the signals that regulate eosinophil survival and death is critical to developing new treatments for asthma, atopy, and gastrointestinal disease. Previous studies suggest that TNF-α stimulation protects eosinophils from apoptosis, and this TNF-α-mediated protection is mediated by the upregulation of an unknown protein by NF-κB. Here, we show for the first time that eosinophils express the caspase 8-inhibitory protein c-FLIP, and c-FLIP expression is upregulated upon TNF-α stimulation. Considering that c-FLIP expression is regulated by NF-κB, we hypothesized that c-FLIP might serve as the “molecular switch” that converts TNFRI activation to a pro-survival signal in eosinophils. Indeed, we found that one c-FLIP isoform, c-FLIP_L, is required for mouse eosinophil survival in the presence of TNF-α both in vitro and in vivo. Importantly, our results suggest c-FLIP as a potential therapeutic target for the treatment of eosinophil-mediated disease.     

Improved production of biohydrogen in light-powered Escherichia coli by co-expression of proteorhodopsin and heterologous hydrogenase

Background

Solar energy is the ultimate energy source on the Earth. The conversion of solar energy into fuels and energy sources can be an ideal solution to address energy problems. The recent discovery of proteorhodopsin in uncultured marine ??-proteobacteria has made it possible to construct recombinant Escherichia coli with the function of light-driven proton pumps. Protons that translocate across membranes by proteorhodopsin generate a proton motive force for ATP synthesis by ATPase. Excess protons can also be substrates for hydrogen (H₂) production by hydrogenase in the periplasmic space. In the present work, we investigated the effect of the co-expression of proteorhodopsin and hydrogenase on H₂ production yield under light conditions.

Results

Recombinant E. coli BL21(DE3) co-expressing proteorhodopsin and [NiFe]-hydrogenase from Hydrogenovibrio marinus produced ~1.3-fold more H₂ in the presence of exogenous retinal than in the absence of retinal under light conditions (70 ??mole photon/(m²·s)). We also observed the synergistic effect of proteorhodopsin with endogenous retinal on H₂ production (~1.3-fold more) with a dual plasmid system compared to the strain with a single plasmid for the sole expression of hydrogenase. The increase of light intensity from 70 to 130 ??mole photon/(m²·s) led to an increase (~1.8-fold) in H₂ production from 287.3 to 525.7 mL H₂/L-culture in the culture of recombinant E. coli co-expressing hydrogenase and proteorhodopsin in conjunction with endogenous retinal. The conversion efficiency of light energy to H₂ achieved in this study was ~3.4%.

Conclusion

Here, we report for the first time the potential application of proteorhodopsin for the production of biohydrogen, a promising alternative fuel. We showed that H₂ production was enhanced by the co-expression of proteorhodopsin and [NiFe]-hydrogenase in recombinant E. coli BL21(DE3) in a light intensity-dependent manner. These results demonstrate that E. coli can be applied as light-powered cell factories for biohydrogen production by introducing proteorhodopsin.     

The effect of high intensity focused ultrasound treatment on metastases in a murine melanoma model

This study aims to assess the risk of high intensity focused ultrasound (HIFU) therapy on the incidence of distant metastases and to investigate its association with HIFU-elicited anti-tumor immunity in a murine melanoma (B16-F10) model. Tumor-bearing legs were amputated immediately after or 2 days following HIFU treatment to differentiate the contribution of the elicited anti-tumor immunity. In mice undergoing amputation immediately after mechanical, thermal, or no HIFU treatment, metastasis rates were comparable (18.8%, 13.3%, and 12.5%). In contrast, with a 2-day delay in amputation, the corresponding metastasis rates were 6.7%, 11.8%, and 40%, respectively. Animal survival rate was higher and CTL activity was enhanced in the HIFU treatment groups. Altogether, our results suggest that HIFU treatment does not increase the risk of distant metastasis. Instead, HIFU treatment can elicit an anti-tumor immune response that may be harnessed to improve the overall effectiveness and quality of cancer therapy.