Conformational studies of soluble and immobilized frog epidermis tyrosinase by fluorescence

Fluorescence spectra and soluble quenching of intrinsic protein fluorescence were used as indexes of conformational changes suffered by frog epidermis tyrosinase. The activation process and the immobilization of the enzyme involving either free amino groups or its carbohydrate moiety were studied. The conformational changes resulting from denaturation of each one of the protein derivatives, as well as the effect of active center copper extraction, were followed by fluorescence studies. The results showed that: (a) both activation and immobilization were accompanied by conformational changes of the protein leading to more unfolded states; (b) neither enzyme nor immobilized enzyme were fully unfolded upon denaturation although enzymic activity was lost; (c) the enzyme immobilized through its carbohydrate moiety was more unfolded upon denaturation than the enzyme immobilized through amino groups, thus pointing to a higher conformational stabilization in the last situation; and (d), that tryptophyl residues moved to a localization near the active site upon activation.     

Microanatomy and ultrastructure of outer mantle epidermis of the cuttlefish,Sepia esculenta (Cephalopoda: Sepiidae)

This study describes the ultrastructural characteristics of external epidermis of mantle of Sepia esculenta using light and electron microscopy. The epidermis was thicker on the ventral surface than on the dorsal surface, with a higher secretory cell distribution on the ventral surface than on the dorsal surface. The epidermis was a single layer composed of epithelial cells, secretory cells, ciliated cells and neuroglial cells. Epithelial cells were columnar with well-developed microvilli on the free surface, and the microvilli were covered with glycocalyx. The epithelial cells were connected to the neighboring cells by tight junctions and membrane interdigitations of the apico-frontal surface. Well-developed microfilaments were arranged in a vertical direction in the cortical cytoplasm. The secretory cells were categorized into three types (A, B and C) in accordance with the light microscopical characteristics and ultrastructures of the secretory granules. The distribution of these cells was in the following order: Type A > Type B > Type C. SEM observation revealed that the secretory pore size of the Type A secretory cells was approximately 8.6 μm × 12.2 μm. Cytoplasm displayed a red color as the result of Masson's trichrome stain and H–E stain, and contained polygonal granules of approximately 1.2 μm² with a high electron density. The secretory pore size of the Type B secretory cells was approximately 10.1 μm × 12.1 μm. As the results of AB–PAS (pH 2.5) and AF–AB (pH 2.5) reactions, the cytoplasm displayed a red color. The cells contained membrane bounded secretory granules with very low electron density. The secretory pore of the Type C secretory cells was circular shape, and approximately 5.5 μm × 5.5 μm. Cytoplasm was found to be homogeneous under H–E stain and Masson's trichrome stain, and displayed a red color. As the result of AB–PAS (pH 2.5) reaction, the cytoplasm displayed a red color. The electron density of the secretory substance was the highest among the three types of secretory cells. The ciliated cells had a ciliary tuft on the free surface and were distributed throughout the mantle with the exception of the adhesive organs. Neuroglial cells were connected to the basal membrane, epithelial cells, secretory cells and nerve fibers through cytoplasmic process, and contained neurosecretory granules with high electron density within the cytoplasm.     

IR Fourier Spectroscopy in Vivo of Human Skin during Its Ablation on Exposure to YAG:Er Laser Radiation and Polarization of the Light Scattered by the Integument

We consider the possibility of monitoring the process of human skin ablation on exposure to pulsed IR laser radiation with the use of the polarization and IR Fourier spectroscopy of disturbed total internal reflection. The laws of the change in the content of water and proteins in the surface layers of skin as a result of cyclic laser effect have been discovered. The interrelation between the degree of polarization of the backward scattered probe radiation with the wavelength corresponding to the maxima of absorption of an oxygenated form of hemoglobin and the index of erythema occurring due to laser action has been established.     

Simultaneous determination of benzophenone-3, retinol and retinyl acetate in pig ear skin layers by high-performance liquid chromatography

A new and simple HPLC method was developed and validated for the simultaneous determination of benzophenone-3, retinol and retinyl acetate in pig ear skin layers and percutaneous penetration samples after in vitro permeation experiments. HPLC analysis was performed utilizing a NovaPak C18 column with acetonitrile-water-acetic acid as mobile phase. UV detection was at 325 nm and the run time was 25 min. The detector response was found to be accurate, precise and linear across the analytical range. Analyte extraction from skin layers was done with methanol from the stratum corneum and epidermis, and with acetone from the dermis. Recovery was in all cases better than 90%. The HPLC assay and extraction procedure proposed are simple, rapid, sensitive and accurate. The method was then applied for the determination of benzophenone-3, retinol and retinyl acetate in pig ear skin layers after topical application.     

Saturation Effects on Immunopathogenic Mechanism of Psoriasis:A theoretical approach

Psoriasis vulgaris is a common chronic autoimmune inflammatory skin disease characterized by T-cell mediated hyper proliferation of keratinocytes.This type of skin disorder is characterized by macroscopic and also microscopic skin alterations.It was observed that,psoriatic lesions are sharply demarcated,red and slightly raised lesions along with silver whitish scales.The striking feature of T-cell mediated chronic psoriatic lesions are the epidermal infiltration of predominantly oligoclonal CD8~+T-cells ...     

Profiling of widely targeted metabolomics for the identification of chemical composition in epidermis,xylem and pith of Gleditsiae Spina

Gleditsiae Spina, the thorn of Gleditsia sinensis Lam., has a long history of being used as a traditional medicine in East Asian countries. However, only a few biologically active substances have been identified from it. In this study, the epidermis, xylem and pith of Gleditsiae Spina, respectively Gs-E, Gs-X and Gs-P, were studied. We used a widely targeted metabolomics method to investigate the chemical composition of Gs-E, Gs-X and Gs-P. A total of 728 putative metabolites were identified from Gleditsiae Spina, including 211 primary metabolites and 517 secondary metabolites. These primary and secondary metabolites could be categorized into more than 10 different classes. Flavonoids, phenolic acids, lipids, amino acids and derivatives, and organic acids constituted the main metabolite groups. Multivariate statistical analysis showed that the Gs-E, Gs-X and Gs-P samples could be clearly separated. Differential accumulated metabolite (DAM) analysis revealed that more than half of the DAMs exhibited the highest relative concentrations in Gs-E, and most of the DAMs showed the lowest relative concentrations in Gs-X. Moreover, 11 common differential primary metabolites and 79 common differential secondary metabolites were detected in all comparison groups. These results further our understanding of chemical composition and metabolite accumulation of Gleditsiae Spina.     

薹草属广义菱形果薹草组（莎草科）的叶表皮微形态特征及其分类学意义

利用光学显微镜,对薹草属广义菱形果薹草组Carexsect.Rhomboidales s.l.(莎草科)54种、2亚种、8变种,共76个样品进行了叶片表皮形态特征的观察研究.结果表明:表皮细胞形状和垂周壁式样在大多数种中表现出稳定性,上、下表皮细胞大多为长方形,少数为近方形、近圆形或长条形,其垂周壁式样多为深波状,少数为波状;气孔器在下表皮脉间呈列或随机分布,气孔的大小、气孔指数及密度在种内有差异;有些种具硅质乳突,而表皮附属物分为刺突和刺毛2种,刺突常出现在sect.Rhomboidales s.str.的成员中.根据表皮的各项性状尚无法区分sect.Rhomboidales s.str.和sect.Careyanae,叶表皮性状近缘种之间存在显著区别,可以作为区分种或种下类群的依据.     

Hexamethyldisiloxane‐modified ZnO‐SiO2‐coated superhydrophobic textiles for antibacterial application

A superhydrophobic cotton textile with high antibacterial properties has been fabricated. The cotton textile was coated through the in situ growth of ZnO‐SiO₂ nanoparticles in presence of chitosan as the template agent via a hydrothermal process at 95 °C. This process was followed by the coating of additional layers of hexadecyltrimethoxysilane (HDTMS). The obtained cotton textile showed antibacterial property against Staphylococcus epidermis and Escherichia coli with inhibition zones up to 18.26 and 8.48 mm, respectively. Scanning electron microscopy (SEM) revealed that the coating had a rough surface, which was attributed to the distribution of ZnO‐SiO₂ nanorods of hexagonal shape. This rough surface creates a superhydrophobic layer that repels the bacteria, as proven by the large water contact angle of approximately 150°. Nevertheless, the HDTMS layers prolong the durability of hydrophobicity for up to 3 h.     

Diverse Localization Patterns of an R-Type Lectin in Marine Annelids

Lectins facilitate cell–cell contact and are critical in many cellular processes. Studying lectins may help us understand the mechanisms underlying tissue regeneration. We investigated the localization of an R-type lectin in a marine annelid (Perinereis sp.) with remarkable tissue regeneration abilities. Perinereis nuntia lectin (PnL), a galactose-binding lectin with repeating Gln-X-Trp motifs, is derived from the ricin B-chain. An antiserum was raised against PnL to specifically detect a 32-kDa lectin in the crude extracts from homogenized lugworms. The antiserum detected PnL in the epidermis, setae, oblique muscle, acicula, nerve cord, and nephridium of the annelid. Some of these tissues and organs also produced Galactose (Gal) or N-acetylgalactosamine (GalNAc), which was detected by fluorescent-labeled plant lectin. These results indicated that the PnL was produced in the tissues originating from the endoderm, mesoderm, and ectoderm. Besides, the localizing pattern of PnL partially merged with the binding pattern of a fluorescent-labeled mushroom lectin that binds to Gal and GalNAc. It suggested that PnL co-localized with galactose-containing glycans in Annelid tissue; this might be the reason PnL needed to be extracted with haptenic sugar, such as d-galactose, in the buffer. Furthermore, we found that a fluorescein isothiocyanate-labeled Gal/GalNAc-binding mushroom lectin binding pattern in the annelid tissue overlapped with the localizing pattern of PnL. These findings suggest that lectin functions by interacting with Gal-containing glycoconjugates in the tissues.