Possible anti-obesity therapeutics from nature – A review

Obesity is associated with many diseases, particularly diabetes, hypertension, osteoarthritis, and heart disease. The obesity incidence has increased at an alarming rate in recent years, becoming a worldwide health problem, with incalculable social costs. Two different obesity-treatment drugs are currently on the market: orlistat, which reduces intestinal fat absorption via inhibiting pancreatic lipase; and sibutramine, an anorectic or appetite suppressant. Both drugs have hazardous side-effects, including increased blood pressure, dry mouth, constipation, headache, and insomnia. For this reason, a wide variety of natural materials have been explored for their obesity treatment potential. These are mainly complex products having several components with different chemical and pharmacological features. This review aimed to survey the literature covering natural products with anti-obesity activity and to review the scientific data, including experimental methodologies, active components, and mechanisms of action against obesity.     

Microbial Communities in the Upper Respiratory Tract of Patients with Asthma and Chronic Obstructive Pulmonary Disease

Respiratory infections are well-known triggers of chronic respiratory diseases. Recently, culture-independent tools have indicated that lower airway microbiota may contribute to pathophysiologic processes associated with asthma and chronic obstructive pulmonary disease (COPD). However, the relationship between upper airway microbiota and chronic respiratory diseases remains unclear. This study was undertaken to define differences of microbiota in the oropharynx of asthma and COPD patients relative to those in healthy individuals. To account for the qualitative and quantitative diversity of the 16S rRNA gene in the oropharynx, the microbiomes of 18 asthma patients, 17 COPD patients, and 12 normal individuals were assessed using a high-throughput next-generation sequencing analysis. In the 259,572 total sequence reads, α and β diversity measurements and a generalized linear model revealed that the oropharynx microbiota are diverse, but no significant differences were observed between asthma and COPD patients. Pseudomonas spp. of Proteobacteria and Lactobacillus spp. of Firmicutes were highly abundant in asthma and COPD. By contrast, Streptococcus, Veillonella, Prevotella, and Neisseria of Bacteroidetes dominated in the healthy oropharynx. These findings are consistent with previous studies conducted in the lower airways and suggest that oropharyngeal airway microbiota are important for understanding the relationships between the various parts of the respiratory tract with regard to bacterial colonization and comprehensive assessment of asthma and COPD.     

Functional characterization of extracellular chitinase encoded by the YlCTS1 gene in a dimorphic yeast Yarrowia lipolytica

The hemiascomycetes yeast Yarrowia lipolytica is a dimorphic yeast with alternating yeast and mycelia forms. Bioinformatic analysis revealed the presence of three putative chitinase genes, YlCTS1, YlCTS2, and YlCTS3, in the Y. lipolytica genome. Here, we demonstrated that the protein of YlCTS1 (YlCts1p), which contains an N-terminal secretion signal peptide, a long C-terminal Ser/Thr-rich domain, and a chitin-binding domain, is a homologue to Saccharomyces cerevisiae chitinase 1 (ScCts1p). Deletion of YlCTS1 remarkably reduced extracellular endochitinase activity in the culture supernatant of Y. lipolytica and enhanced cell aggregation, suggesting a role of YlCts1p in cell separation as ScCts1p does in S. cerevisiae. However, loss of YlCts1p function did not affect hyphal formation induced by fetal bovine serum addition. The mass of YlCts1p was dramatically decreased by jack bean α-mannosidase digestion but not by PNGase F treatment, indicating that YlCts1p is modified only by O-mannosylation without N-glycosylation. Moreover, the O-glycan profile of YlCts1p was identical to that of total cell wall mannoproteins, supporting the notion that YlCts1p can be used as a good model for studying O-glycosylation in this dimorphic yeast.     

Kolloidmodelle zur Illustration biologischer Vorgänge

Ohne Zusammenfassung     

Alignment and focusing unit for dual-laser excitation in the fluorescence-activated cell sorter

The two laser beams in a dual-laser fluorescence-activated cell sorter FACS-II can be aligned and focused independently on the sample stream with an additional unit, which can be fitted easily on the optical bench of the FACS. The unit consists of two spherical lenses, which have been mounted in separate holders and can be moved in three directions by way of micrometer gauges. The lenses, which have different focal lengths, have been cut off on one side so each laser beam only passes one lens. The setup has been tested using the flow analysis of a suspension of double-stained chicken red blood cells. The histograms of both fluorescence signals showed normal distributions with a coefficient of variation of approximately 6%. After willful interference with the adjustments, the laser beams could be readily readjusted within five minutes.     

High‐Voltage‐Driven Surface Structuring and Electrochemical Stabilization of Ni‐Rich Layered Cathode Materials for Li Rechargeable Batteries

Layered lithium–nickel–cobalt–manganese oxide (NCM) materials have emerged as promising alternative cathode materials owing to their high energy density and electrochemical stability. Although high reversible capacity has been achieved for Ni‐rich NCM materials when charged beyond 4.2 V versus Li⁺/Li, full lithium utilization is hindered by the pronounced structural degradation and electrolyte decomposition. Herein, the unexpected realization of sustained working voltage as well as improved electrochemical performance upon electrochemical cycling at a high operating voltage of 4.9 V in the Ni‐rich NCM LiNi_0.895Co_0.085Mn_0.02O₂ is presented. The improved electrochemical performance at a high working voltage at 4.9 V is attributed to the removal of the resistive Ni²⁺O rock‐salt surface layer, which stabilizes the voltage profile and improves retention of the energy density during electrochemical cycling. The manifestation of the layered Ni²⁺O rock‐salt phase along with the structural evolution related to the metal dissolution are probed using in situ X‐ray diffraction, neutron diffraction, transmission electron microscopy, and X‐ray absorption spectroscopy. The findings help unravel the structural complexities associated with high working voltages and offer insight for the design of advanced battery materials, enabling the realization of fully reversible lithium extraction in Ni‐rich NCM materials.     

Retarded Charge–Carrier Recombination in Photoelectrochemical Cells from Plasmon‐Induced Resonance Energy Transfer

N‐type metal oxides such as hematite (α‐Fe₂O₃) and bismuth vanadate (BiVO₄) are promising candidate materials for efficient photoelectrochemical water splitting; however, their short minority carrier diffusion length and restricted carrier lifetime result in undesired rapid charge recombination. Herein, a 2D arranged globular Au nanosphere (NS) monolayer array with a highly ordered hexagonal hole pattern (hereafter, Au array) is introduced onto the surface of photoanodes comprised of metal oxide films via a facile drying and transfer‐printing process. Through plasmon‐induced resonance energy transfer, the Au array provides a strong electromagnetic field in the near‐surface area of the metal oxide film. The near‐field coupling interaction and amplification of the electromagnetic field suppress the charge recombination with long‐lived photogenerated holes and simultaneously enhance the light harvesting and charge transfer efficiencies. Consequently, an over 3.3‐fold higher photocurrent density at 1.23 V versus reversible hydrogen electrode (RHE) is achieved for the Au array/α‐Fe₂O₃. Furthermore, the high versatility of this transfer printing of Au arrays is demonstrated by introducing it on the molybdenum‐doped BiVO₄ film, resulting in 1.5‐fold higher photocurrent density at 1.23 V versus RHE. The tailored metal film design can provide a potential strategy for the versatile application in various light‐mediated energy conversion and optoelectronic devices.     

Revisiting the Role of Conductivity and Polarity of Host Materials for Long‐Life Lithium–Sulfur Battery

Despite their high theoretical energy density and low cost, lithium–sulfur batteries (LSBs) suffer from poor cycle life and low energy efficiency owing to the polysulfides shuttle and the electronic insulating nature of sulfur. Conductivity and polarity are two critical parameters for the search of optimal sulfur host materials. However, their role in immobilizing polysulfides and enhancing redox kinetics for long‐life LSBs are not fully understood. This work has conducted an evaluation on the role of polarity over conductivity by using a polar but nonconductive platelet ordered mesoporous silica (pOMS) and its replica platelet ordered mesoporous carbon (pOMC), which is conductive but nonpolar. It is found that the polar pOMS/S cathode with a sulfur mass fraction of 80 wt% demonstrates outstanding long‐term cycle stability for 2000 cycles even at a high current density of 2C. Furthermore, the pOMS/S cathode with a high sulfur loading of 6.5 mg cm^?2 illustrates high areal and volumetric capacities with high capacity retention. Complementary physical and electrochemical probes clearly show that surface polarity and structure are more dominant factors for sulfur utilization efficiency and long‐life, while the conductivity can be compensated by the conductive agent involved as a required electrode material during electrode preparation. The present findings shed new light on the design principles of sulfur hosts towards long‐life and highly efficient LSBs.     

Insect diversity in Gonggeom‐ji,the first protected paddy field wetland in Korea

Gonggeom‐ji pond is the first protected paddy field wetland area, designated by the Ministry of Environment of Korea in 2011, because of its high biodiversity and historic value. It contains reservoirs, paddy fields, and a forest site that provides diverse niches for insects. Quantitative methods were used in this study to estimate the insect diversity of this region. A transect of 50 m was designated in each site (reservoirs, paddy fields, and a forest site). Data were collected using sweeping and pitfall traps along each transect in May, August, and November 2017, representative of the seasons—spring, summer, and autumn, respectively. As a result, a total of 1079 individual insects representing 170 species from 60 families within nine orders were collected. Diversity, richness, and evenness indices were the highest in the forest site in May (4.77, 8.6, and 0.91, respectively). The dominance index was the highest in the forest site in November (0.64). Similarity index was the highest in the reservoir in May and August (0.519). These results would help compare different sites and their vegetation to assess relationships between insects and habitats.