A Strategy to Probe Air-Liquid Interfaces by Confocal Fluorescence Microscopy

Abstract

Confocal fluorescence microscopy has been seldom applied to air-liquid interfaces due to technical difficulties. Satellite lines of an excitation laser beam can be used as an inherent reference for a confocal microscope to align and calibrate the setup. This strategy is especially useful and important to a liquid surface, and makes it possible to observe very weak fluorescence without time-consuming alignment procedures.     

Ipragliflozin Ameliorates Diabetic Nephropathy Associated with Perirenal Adipose Expansion in Mice

Sodium glucose cotransporter-2 (SGLT2) inhibitors inhibit the development of diabetic nephropathy (DN). We determined whether changes in perirenal fat (PRAT) by a SGLT2 inhibitor ipragliflozin (Ipra) contribute to the suppression of DN development. High-fat diet (HFD)-fed mice were used as a DN model and were treated with or without Ipra for 6 weeks. Ipra treatment reduced urinary albumin excretion (UAE) and glomerular hypertrophy in HFD-fed mice. In the PRAT of Ipra-treated mice, adipocyte size was increased, and inflammation, fibrosis, and adipocyte death were suppressed. In conditioned medium made from PRAT (PRAT-CM) of Ipra-treated mice, the concentration of leptin was significantly lower than PRAT-CM of mice without Ipra treatment. Serum leptin concentration in renal vein positively correlated with UAE. PRAT-CM from HFD-fed mice showed greater cell proliferation signaling in mouse glomerular endothelial cells (GECs) than PRAT-CM from standard diet-fed mice via p38MAPK and leptin-dependent pathways, whose effects were significantly attenuated in PRAT-CM from Ipra-treated mice. These findings suggest that Ipra-induced PRAT expansion may play an important role in the improvement of DN in HFD-fed mice. In vitro experiments suggest that reduced PRAT-derived leptin by Ipra could inhibit GECs proliferation, possibly contributing to the suppression of DN development.     

Rodent Models of Nonalcoholic Fatty Liver Disease/Nonalcoholic Steatohepatitis

Research in nonalcoholic fatty liver disease (NAFLD), including nonalcoholic steatohepatitis (NASH), has been limited by the availability of suitable models for this disease. A number of rodent models have been described in which the relevant liver pathology develops in an appropriate metabolic context. These models are promising tools for researchers investigating one of the key issues of NASH: not so much why steatosis occurs, but what causes the transition from simple steatosis to the inflammatory, progressive fibrosing condition of steatohepatitis. The different rodent models can be classified into two large groups. The first includes models in which the disease is acquired after dietary or pharmacological manipulation, and the second, genetically modified models in which liver disease develops spontaneously. To date, no single rodent model has encompassed the full spectrum of human disease progression, but individual models can imitate particular characteristics of human disease. Therefore, it is important that researchers choose the appropriate rodent models. The purpose of the present review is to discuss the metabolic abnormalities present in the currently available rodent models of NAFLD, summarizing the strengths and weaknesses of the established models and the key findings that have furthered our understanding of the disease’s pathogenesis.     

Simulation Analyses on the Diffusion of a Rust-Preventing Oil into an Oil-Accommodating Adhesive

In recent years bonding between two steel plates was accomplished with an oil-accommodating adhesive without requiring degreasing of the steel. In this paper, the exclusion process of the oil was investigated in this adhesive on the assumption that the oil was absorbed into the adhesive layer.

It was found that the oil layer essentially disappeared in the initial step of curing in which the temperature was raised to 180°C, because the diffusion rate of the oil into the adhesive increased abruptly with temperature. Therefore, the bonding process in this case is not influenced by the presence of oil on the steel plates.     

Double‐metal complexation of heterogels containing cyanobacterial polysaccharides

Cryogenic‐transmission electron microscopy of metal complexes with cyanobacterial polysaccharides, sacran, extracted from Aphanothece sacrum biomaterials reveals that Nd³⁺ complexes form networks composed of thick strings with a thickness ranging 10–20 nm while Fe²⁺ ones make dense entanglement of very thin strings. When Fe²⁺ and Nd³⁺ double complexation occurs, dense nanonetworks composed of thick strings with a thickness around 10 nm are formed. Next we prepared heterogels by crosslinking poly(vinyl alcohol) chains in the presence of sacran and investigated the effects of double complexation on metal sorption. The amount of Nd³⁺ sorbed into the heterogels in the 1 : 1 miscible solution of Fe²⁺ and Nd³⁺ is higher than that in the solution containing only Nd^3+, suggesting that Fe²⁺ assists the Nd³⁺ sorption. In addition, it is found that the amount of sorbed Nd³⁺ is much higher than that of sorbed Fe²⁺ even in the acidic condition of pH 2. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Enhanced bactericidal action and masking of allergen structure of soy protein by attachment of chitosan through Maillard‐type protein‐polysaccharide conjugation

The soy protein‐chitosan conjugate was formed by the Maillard reaction in dry state (relative humidity 65%) at 60°C for 2 weeks to improve the functional properties. The antimicrobial activity of the Maillard‐type soy protein‐chitosan conjugates enhanced 2–3 times that of soy protein‐chitosan mixture. The soy protein‐chitosan conjugate showed excellent emulsifying property with the progress of Maillard‐type conjugation. The allergenicity of soy protein was greatly decreased by the attachment of chitosan through Maillard reaction. The immonoblotting analysis with patient's sera revealed that soy protein‐chitosan conjugate was more effective to mask the allergen structure of soy protein causing from 34 kDa‐protein (Gly m Bd 30K) than soy protein‐galactomannan conjugate. The Western blotting showed that allergen (34 kDa‐protein) was completely masked by soy protein‐chitosan conjugation, while it was not completely masked by soy protein‐galactomannan conjugation.     

Effect of d‐Psicose Used as Sucrose Replacer on the Characteristics of Meringue

Excessive intake of sugar‐rich foods leads to metabolic syndrome. d ‐Psicose (Psi) not commonly found in nature, is noncalorie sweetener with a suppressive effect on the blood glucose level. Thus, Psi has the potential to be utilized as a sucrose (Suc) replacer in sugar‐rich foods, including meringue‐based confectionery (MBC). In this study, we investigated the effect of Psi on the physical and chemical properties of meringue. Meringue was made by whipping egg white and Suc (at a weight ratio of 1:1) and baking at 93 °C for 2 h. Thirty percent of the total weight of Suc was replaced with d ‐ketohexoses such as Psi, d ‐fructose, d ‐tagatose, and d ‐sorbose. The meringues containing d ‐ketohexoses had higher specific volume than the meringue not containing d ‐ketohexoses (Ct‐meringue). Baking of meringue caused differences between Psi and the other d ‐ketohexose meringues. Meringue containing Psi (P30‐meringue) had the highest breaking stress (7.00 × 10⁵ N/m²) and breaking strain (4.40%), resulting in the crunchiest texture. In addition, P30‐meringue also had the highest antioxidant activity (491.84 μM TE/mg‐meringue determined by ABTS method) and was the brownest due to a Maillard reaction occurring during baking. The replacement of Suc with Psi improved the characteristics of baked meringue. Thus, Psi was found to be useful in modifying the physical and chemical properties of MBC.     

Production of conjugated fatty acids by lactic acid bacteria

Conjugated fatty acids have attracted much attention as a novel type of biologically beneficial functional lipid. Some isomers of conjugated linoleic acid (CLA) reduce carcinogenesis, atherosclerosis, and body fat. Considering the use of CLA for medicinal and nutraceutical purposes, a safe isomer-selective process is required. The introduction of biological reactions for CLA production could be an answer. We screened microbial reactions useful for CLA production, and found several unique reactions in lactic acid bacteria. Lactic acid bacteria produced CLA from linoleic acid. The produced CLA comprised a mixture of cis-9,trans-11-octadecadienoic acid (18:2) and trans-9,trans-11-18:2. Lactobacillus plantarum AKU 1009a was selected as a potential CLA producer. Using washed cells of L. plantarum AKU 1009a as a catalyst, CLA production from linoleic acid reached 40 mg/ml under the optimized conditions. The CLA-producing reaction was found to consist of two successive reactions, i.e., hydration of linoleic acid to 10-hydroxy-12-octadecenoic acid and dehydrating isomerization of the hydroxy fatty acid to CLA. On the basis of these results, the transformation of hydroxy fatty acids by lactic acid bacteria was investigated. Lactic acid bacteria transformed ricinoleic acid (12-hydroxy-cis-9-octadecenoic acid) to CLA (a mixture of cis-9,trans-11-18:2 and trans-9,trans-11-18:2). Castor oil, which is rich in the triacylglycerol form of ricinoleic acid, was also found to act as a substrate for CLA production by lactic acid bacteria with the aid of lipase-catalyzed triacylglycerol hydrolysis. L. plantarum AKU 1009a produced conjugated trienoic fatty acids from alpha- and gamma-linolenic acid. The trienoic fatty acids produced from alpha-linolenic acid were identified as cis-9,trans-11,cis-15-octadecatrienoic acid (18:3) and trans-9,trans-11,cis-15-18:3. Those produced from gamma-linolenic were cis-6,cis-9,trans-11-18:3 and cis-6,trans-9,trans-11-18:3. The conjugated trienoic fatty acids produced from alpha- and gamma-linolenic acid were further saturated by L. plantarum AKU 1009a to trans-10,cis-15-18:2 and cis-6,trans-10-18:2, respectively.