Three-dimensional image-guided topical photodynamic therapy system with light dosimetry dynamic planning and monitoring.

Photodynamic therapy (PDT) has shown significant potential for skin disease treatment. As a key element, light is critical to influencing its treatment outcome, and light dosimetry is an issue of much concern for researchers. However, because of three-dimensional irregularity in shape and patient's movement during the therapy, irradiance hardly keeps uniform on the lesion and flux measurement remains a challenge. In this work, we report the development of a three-dimensional image-guided PDT system, and the method of dynamic irradiance planning and flux monitoring for lesions in different poses. This system comprises a three-dimensional camera for monitoring patients' movement during therapy, a computer for data analysis and processing, and a homemade LED array for forming uniform irradiance on lesions. Simulations on lesions of the face and arm show that the proposed system significantly increases effective therapy area, enhances irradiance uniformity, is able to visualize flux on the lesion, and reduces risks of burns during PDT. The developed PDT system is promising for optimizing procedures of PDT and providing better treatment outcomes by delivering controllable irradiance and flux on lesions even when a patient is moving.

Extraction optimization, purification, and biological properties of polysaccharide from Chinese yam peel.

In this study, the Chinese yam peel polysaccharide (CYPP) was obtained under the extraction conditions optimized by the Response Surface Methodology (RSM). Further biological properties of CYPP-1 purified from CYPP were also determined. The results indicated that the optimum extraction conditions were an extraction temperature of 90.5°C, a liquid-solid ratio of 28.0 ml/g, and an extraction time of 2.94 h, along with a yield of 8.81 ± 1.48%. CYPP-1 was identified as a kind of heteropolysaccharide mostly composed of glucose and galactose (59.4:1.0). The molecular weights were two main parts of 50.5 kDa (54.77%) and 4.4 kDa (21.02%), and the triple-helix conformation was not formed in CYPP-1. Besides, CYPP-1 showed good biological properties including in vitro antioxidant activity and immunomodulatory function on RAW264.7 cells, as well as favorable hypoglycemic effect. Overall, the high-value utilization of CYPP-1 reveals a broad application prospect in the industrial production of functional foods and pharmaceuticals. PRACTICAL APPLICATIONS: Yam peel, which is discarded in large quantities during postharvest processing, results in the production of tremendous by-products and is a great waste of resources. In this study, the yield of water-soluble polysaccharide from yam peel reached 8.81 ± 1.48%. Besides, the purified CYPP-1 exhibited excellent antioxidant activity, favorable immunomodulatory function, and hypoglycemic effect. The high productivity and bioactive effects are both great merits for Chinese yam peel polysaccharide as a promising candidate for foods and medicines industrial production.

Recruitment of AtWHY1 and AtWHY3 by a distal element upstream of the kinesin gene AtKP1 to mediate transcriptional repression.

A 43-bp distal element, the AtKP1-related element (KPRE), was previously shown to repress the promoter activity of the kinesin gene AtKP1 in Arabidopsis thaliana. In order to identify KPRE-binding factor 1 (KBF1), a combination of ion-exchange chromatography, gel-filtration chromatography and DNA-affinity chromatography was used to purify KBF1 from whole cell extracts of Arabidopsis seedlings. Mass spectrometric identification showed that KBF1 contains two members of the whirly family of transcription factors, AtWHY1 and AtWHY3. KBF1 is a single and double-stranded DNA-binding factor. A ChIP assay showed that AtWHY1 and AtWHY3 bind to the upstream region of AtKP1 gene in vivo. Over-expression of AtWHY1 and AtWHY3 led to an obvious decrease of AtKP1 transcripts, based on quantitative real-time PCR analysis. Interestingly, salicylic acid treatment resulted in an increase of AtWHY1 and AtWHY3 transcripts, and a decrease of AtKP1 transcripts. Thus, AtWHY1 and AtWHY3, as two components of KBF1, can be recruited at the KPRE site to mediate the transcriptional repression of AtKP1. Our results prove that AtKP1 is a new downstream target of the whirly family of transcription factors.

A cotton kinesin GhKCH2 interacts with both microtubules and microfilaments.

Many biological processes require the co-operative involvement of both microtubules and microfilaments; however, only a few proteins mediating the interaction between microtubules and microfilaments have been identified from plants. In the present study, a cotton kinesin GhKCH2, which contains a CH (calponin homology) domain at the N-terminus, was analysed in vitro and in vivo in order to understand its interaction with the two cytoskeletal elements. A specific antibody against GhKCH2 was prepared and used for immunolabelling experiments. Some GhKCH2 spots appeared along a few microtubules and microfilaments in developing cotton fibres. The His-tagged N-terminus of GhKCH2 (termed GhKCH2-N) could co-precipitate with microfilaments and strongly bind to actin filaments at a ratio of monomeric actin/GhKCH2-N of 1:0.6. The full-length GhKCH2 recombinant protein was shown to bind to and cross-link microtubules and microfilaments in vitro. A GFP-fusion protein GFP-GhKCH2 transiently overexpressed in Arabidopsis protoplasts decorated both microtubules and microfilaments, confirming the binding ability and specificities of GhKCH2 on microtubules and microfilaments in living plant cells. The results of the present study demonstrate that GhKCH2, a plant-specific microtubule-dependent motor protein, not only interacts with microtubules, but also strongly binds to microfilaments. The cytoskeletal dual-binding and cross-linking ability of GhKCH2 may be involved in the interaction between microtubules and microfilaments and the biological processes they co-ordinate together in cotton cells.

A 43-bp A/T-rich element upstream of the kinesin gene AtKP1 promoter functions as a silencer in Arabidopsis.

The expression of the Arabidopsis thaliana kinesin-like protein 1 (AtKP1) gene is restricted to tender tissues. We used a 5'-deletion assay to identify and characterize the regulatory regions controlling tissue-specific AtKP1 expression. Multiple enhancer regions, located 470- and 2,808-bp upstream of the translational start codon, were critical for activation, while a silencer region located at -2,987 to -2,808 (A + T = 71%) was required for repression. Within this 180-bp fragment, a 43-bp element (termed KPRE, A + T = 58%) mediated repression of the CaMV35S promoter by using a gain-of-function approach that was orientation-dependent in leaves and orientation-independent in roots. Electrophoretic mobility shift assay (EMSA) showed that the GAGAAATT octamer (corresponding to neucleotides -2,908 - -2,900) in KPRE was the core negative regulatory motif for interacting with DNA-binding proteins in leaves and roots. However, using a second gain-of-function experiment with KPRE fused to CaMV35S, we found that the mutant negatively affected transcription in transgenic leaves and positively affected transcription in transgenic roots. This indicated that these two modes mediate repressive regulation in leaves and roots, respectively. The EMSA experiment using different mutant KPRE as probes confirmed that two distinct sets of proteins bound to KPRE at an overlapping site AGAAAT in the leaf. Taken together, these data suggest that two different modes control the negatively transcriptional regulation of KPRE in leaves and roots, and provide new insight into the mechanism of transcriptional repression of A/T-rich sequences in higher plants.