Measurement of Zinc Ions in Seawater Samples Using a Microfluidic System Based on the GR/CeO2/Nafion Material.

Considering that heavy-metal contamination of seawater is getting worse, building a quick, accurate and portable device for detecting trace zinc in seawater in real time would be very beneficial. In this work, a microfluidic system was developed that includes a planar disc electrode, a micro-cavity for detection, an electrochemical workstation, a computer, a container for waste liquid reprocessing, an external pipeline and other components as well as a graphene/cerium oxide/nano-cerium oxide/Nafion composite membrane was used to modify the planar disc electrode (GR/CeO2/Nafion/Au) to investigate the electrochemical behaviour of Zn(II) using cyclic voltammetry, square-wave voltammetry and orthogonal test methods. Under optimal experimental conditions, the peak reaction current of Zn(II) showed a good linear relationship with the concentration of Zn(II) in the range of 1-900 µg/L with a correlation coefficient of 0.998, and the detection limit of the method was 0.87 µg/L. In addition, the microfluidic system had good stability, reproducibility and anti-interference. The system was used for determining zinc ions in real seawater samples, and the results were very similar to those of inductively coupled plasma-emission spectrometry, demonstrating the practicality of the system for the detection of trace zinc.

Exclusive Core-Janus Satellite Assembly Based on Au-Ag Janus Self-Aligned Distributions with Abundant Hotspots for Ultrasensitive Detection of CA19-9.

The development of surface-enhanced Raman scattering (SERS) probes with high sensitivity and stability is imminent to improve the accuracy of cancer diagnosis. Here, an exclusive core-Janus satellite (CJS) assembly was constructed by a hierarchical assembly strategy in which the Au-Ag Janus satellite is vertically self-aligned on the core surface. In the process, a silica shell template was ingeniously employed to asymmetrically mask the presatellites for the in situ formation of the Janus structure, and a series of Janus satellites with different morphologies were developed by regulating the encapsulated area of the presatellites. The ordered-oriented arrangement of Au-Ag Janus and unique heterojunction morphology permit CJS assemblies, featuring two types of plasmonic nanogaps, including intrananocrevices for individual Janus and internanogaps between neighboring Janus, thereby multiplying the "hotspots" compared to conventional core-monotonous satellites, which contributes to superior SERS activity. As anticipated, the enhancement factor of CJS assemblies was as high as 3.8 × 108. Moreover, it is intriguing that the directional distribution and head physically immobilized by Janus provided uniform and stable SERS signals. The SERS probe based on the CJS assembly for the detection of carbohydrate antigen 19-9 resulted in an ultrahigh sensitivity with a limit of detection of 3.7 × 10-5 IU·mL-1, which is nearly 10 times lower than other SERS probes, and a wide detection range of 3 × 10-5 to 1 × 104 IU·mL-1. The CJS assembly with excellent SERS performance is promising to advance further development of the early diagnosis of pancreatic cancer.

A Ratiometric Fluorescence Probe for Selective Detection of ex vivo Methylglyoxal in Diabetic Mice.

Accurate monitoring of methylglyoxal (MGO) at cell and living level was crucial to reveal its role in the pathogenesis of diabetes since MGO was closely related to diabetes. Herein, a ratiometric fluorescence strategy was constructed based on the capture probe 2,3-diaminonaphthalene (DAN) for the specific detection of MGO. Compared to the fluorescent probes with a single emission wavelength, the ratiometric mode by monitoring two emissions can effectively avoid the interference from the biological background, and provided additional self-calibration ability, which can realize accurate detection of MGO. The proposed method showed a good linear relationship in the range of 0-75 µm for MGO detection, and the limit of detection was 0.33 µm. DAN responded to MGO with good specificity and was successfully applied for detecting the ex vivo MGO level in plasma of KK-Ay mice as a type II diabetes model. Besides, the prepared DAN test strip can be visualized for rapid semi-quantitative analysis of MGO using the naked eye. Furthermore, human skin fibroblasts and HeLa cells were utilized for exogenous MGO imaging, and ex vivo MGO imaging was performed on tissues of KK-Ay mice. All results indicated that the DAN-based ratiometric fluorescence probe can be used as a potential method to detect the level of MGO, thus enabling indications for the occurrence of diabetes and its complications.

A new polysaccharide from Caulerpa chemnitzia induces molecular shifts of immunomodulation on macrophages RAW264.7.

Investigation on Caulerpa chemnitzia polysaccharides led to the finding of a new polysaccharide (CCP). The basic components of CCP were the total sugar (59.18% ± 0.57%), the uronic acids (36.75% ± 0.28%) and the sulfate (42.50% ± 0.42%), in total content. The physicochemical analysis revealed that CCP was a heteropolysaccharide with a molecular weight of 321.6 KDa, and composed of arabinose, fucose, glucose, mannose, galactose, xylose, fructose, ribose, glucuronic acid and galacturonic acid. The immunomodulatory assay showed that CCP played an important role in activating cell viability, the nitric oxide product and cytokines (IL-6 and TNF-α) secretion. Furthermore, the transcript-metabolic analysis displayed a total of 7692 differentially expressed genes (DEGs) and 95 differentially accumulated metabolites (DAMs), and revealed that CCP may play an immunomodulatory effect by activating NF-κB signaling pathway and arachidonic acid metabolism pathway. These findings will provide a basic understanding to further investigation of Caulerpa polysaccharides.

Immunomodulatory sulfated polysaccharides from Caulerpa racemosa var. peltata induces metabolic shifts in NF-κB signaling pathway in RAW 264.7 macrophages.

Algal polysaccharide activates macrophages to alter physiologic biomarkers to drive the immunomodulatory phenotype, but it lacks specific biomarkers involved in the biochemical underpinning process. Here, we undertook an extensive analysis of the RAW 264.7 macrophages induced by an immunostimulating sulfated polysaccharide from Caulerpa racemosa var. peltata (CRVP-1) employing combined transcriptomic, proteomic, and metabolomic analyses to reveal the molecular details occurring in the CRVP-1-induced immunomodulatory process. The omics profiling of CRVP-1-activated macrophage demonstrated a total of 8844 genes (4354 downregulated and 4490 upregulated), 1243 proteins (620 downregulated and 623 upregulated), and 68 metabolites (52 downregulated and16 upregulated). Further, the co-mapped correlation network of omics combined with Western blot and immunofluorescence staining indicated that the cluster of differentiation 14 (CD14) might assist Toll-like receptor 4 (TLR4) involved in nuclear factor kappa-B (NF-κB) signaling pathway to drive the immunomodulatory phenotype. Together, our results discover novel physiologic biomarkers in the immunomodulatory activities of algal polysaccharides.

Structural characterization and immunological activity of pectin polysaccharide from kiwano (Cucumis metuliferus) peels.

Two novel polysaccharides, namely CMPP-1 and CMPP-2, from kiwano (Cucumis metuliferus) peels were isolated through hot-water extraction, followed by ethanol precipitation and column chromatography. The results showed that CMPP-1 and CMPP-2 were hetero-galacturonans with different molecular weights of 7.35 kDa and 6.90 kDa, respectively. Both of CMPP-1 and CMPP-2 were mainly composed of glucuronic acid (45.93 % and 51.75 %, respectively), and other monosaccharides including rhamnose, arabinose, galactose, glucose, xylose, fucose, mannose, galacturonic acid, and mannuronic acid. The results of structural characterization from FT-IR and NMR confirmed that CMPP-1 and CMPP-2 were pectin with highly branched structure. Furthermore, both CMPP-1 and CMPP-2 possessed immune-enhancing activity and could enhance the secretion of nitric oxide and cytokines (TNF-α, IL-6) in a dose-dependent manner. Especially, CMPP-1 had higher immune activity than CMPP-2 as the minimum effective concentration were 0.78 µg/mL and 6.25 µg/mL, respectively. These findings provide a scientific basis for further utilization of polysaccharide from kiwano peels.

Structural Features of Three Hetero-Galacturonans from Passiflora foetida Fruits and Their in Vitro Immunomodulatory Effects.

Passiflora foetida is a horticultural plant and vital traditional Chinese herbal medicine. In our previous study, the characterization and immuno-enhancing effect of fruits polysaccharide 1 (PFP1), a water-eluted hetero-mannan from wild Passiflora foetida fruits, were investigated. Herein, another three salt-eluted novel polysaccharides, namely PFP2, PFP3, and PFP4, were obtained and structurally characterized. The results showed that PFP2, PFP3, and PFP4 were three structurally similar hetero-galacturonans with different molecular weights of 6.11 × 104, 4.37 × 104, and 3.48 × 105 g/mol, respectively. All three of these hetero-galacturonans are mainly composed of galacturonic acid, galactose, arabinose (75.69%, 80.39%, and 74.30%, respectively), and other monosaccharides including mannose, fucose, glucose, ribose, xylose, and glucuronic acid (24.31%, 19.61, and 25.70%, respectively), although differences in their backbone structure exist. Additionally, immunomodulatory assay indicated that the three hetero-galacturonans possess the ability to promote the production of nitric oxide (NO), tumor necrosis factor-α (TNF-α), and interleukin-6 (IL-6) in RAW264.7 macrophages in a concentration-dependent manner (p < 0.05). Especially, PFP3 displayed a stronger enhancing effect than PFP2 and PFP4 at the minimum effective concentration. Therefore, the results suggested that the obtained three salt-eluted hetero-galacturonans, especially PFP3, could be utilized as immunomodulatory effectivity ingredients in nutritional/pharmaceutical industries.

Structural features, interaction with the gut microbiota and anti-tumor activity of oligosaccharides.

Some oligosaccharides are regarded as biological constituents with benefits to human health in an indirect way. They enter the intestinal tract to be fermented by the gut microbiota, causing changes in the abundance and composition of the gut microbiota and producing fermentation products such as short-chain fatty acids (SCFAs). In this review, the structural features and biological activities of eight common natural oligosaccharides were summarized, including human milk oligosaccharides (HMOS), xylo-oligosaccharides (XOS), arabinoxylo-oligosaccharides (AXOS), isomaltooligosaccharides (IMOS), chitin oligosaccharides (NACOS), mannan-oligosaccharides (MOS), galacto-oligosaccharides (GOS) and fructo-oligosaccharides (FOS). Furthermore, XOS were selected to explain the anti-tumor mechanism mediated by gut microbiota. The review aims to reveal primary structural features of natural functional oligosaccharides related to the biological activities and also provide an explanation of the anti-tumor activity of functional oligosaccharides mediated by the gut microbiota.

Transglutaminase-Catalyzed Encapsulation of Individual Mammalian Cells with Biocompatible and Cytoprotective Gelatin Nanoshells.

Mammalian cells are extremely vulnerable to external assaults compared with plant and microbial cells because of the weakness of cell membranes compared with cell walls. Construction of ultrathin and robust artificial shells on mammalian cells with biocompatible materials is a promising strategy for protecting single cells against harsh environmental conditions. Herein, layer-by-layer assembly combined with a transglutaminase-catalyzed cross-linking reaction was employed to prepare cross-linked and biocompatible gelatin nanoshells on individual human cervical carcinoma cell line (HeLa) cells and mouse insulinoma cell line 6 (MIN6) cells. The encapsulated HeLa and MIN6 cells showed high viability and a prolonged encapsulation period. Moreover, the nanoshells can protect encapsulated cells from cytotoxic enzymes (such as trypsin) and polycation (polyethylenimine) attacks and help cells resist high physical stress. We also investigated how nanoshells would affect the cell viability, proliferation, and cell cycle distribution of encapsulated and released cells. The approach presented here may provide a new and versatile method for nanoencapsulation of individual mammalian cells, which would help cells endure various environmental stresses and thereby expand the application field of isolated mammalian cells.

Structure characterization of a novel polysaccharide from Chinese wild fruits (Passiflora foetida) and its immune-enhancing activity.

A novel polysaccharide (PFP1) with an average molecular weight of 2.02 × 105 g/mol was isolated from Passiflora foetida fruits through hot water extraction, ethanol precipitation and column chromatography. The structure of PFP1 was determined by GPC-MALS-RI, IC, FT-IR, GC-MS and NMR. The structural analysis showed that PFP1 was a heteropolysaccharide and composed of mannose (48.83%), galactose (32.46%), glucose (6.21%), arabinose (5.88%), fructose (2.24%), galacturonic acid (2.20%), xylose (1.17%), fucose (0.17%), ribose (0.05%), and glucuronic acid (0.78%), with a backbone structure of →1)-α-D-Manp→1,2)-ß-D-Manp-linked 1,2,6)-ß-D-Manp residues and side chains consisted of →1)-ß-D-Galp, →1,4)-α-D-Manp, →1, 4)-ß-D-Glcp, →1,3)-α-D-Galp, →1,6)-ß-D-Manp, →1,6)-ß-D-Galp, →1,2,3)-ß-D-Manp and →1,3,6)-ß-D-Galp residues. The results of immune-enhancing assays revealed that PFP1 could obviously promote the production of NO and secretion of cytokines (TNF-α and IL-6) of macrophage RAW264.7. These findings demonstrate that P. foetida fruit polysaccharides can be utilized as a potential immune-enhancing functional food.

Structural characterization and immunostimulatory activity of a novel polysaccharide from green alga Caulerpa racemosa var peltata.

A novel water-soluble polysaccharide (named CRVP-1) was successfully obtained from Caulerpa racemosa var peltata by hot-water extraction, ethanol precipitation, and column chromatography. The structure of CRVP-1 was characterized by HPGPC, HPAEC-PAD, FT-IR, GC-MS and NMR. The structural analysis indicated that CRVP-1 possessed a sulfate content of 25.8%±0.7% and was a heteropolysaccharide with an average molecular weight of 29.68kDa, and composed of mannose, galactose, glucose, galacturonic acid, and glucuronic acid with rates of 92.1%, 2.9%, 1.8%, 1.7% and 1.2%, respectively, owning a backbone structure of (1→6)-linked α-D-Manp residues with (1→4)-linked α-D-Manp and (1→2)-linked α-D-Manp residues and side chain that was consisted of (1→4)-linked ß-D-Galp residues. The immunostimulatory assay revealed that CRVP-1 had significant effects on the proliferation of macrophage, production of NO and secretion of cytokines (TNF-α, IL-1ß and IL-6). These findings provide a scientific basis for further utilization of polysaccharides from C. racemosa var peltata.

Biodiversity and antifouling activity of fungi associated with two soft corals from the South China Sea.

Bacteria in corals have been studied in detail in the past decades. However, the biodiversity and bioactivity of fungi in corals are still poorly understood. This study investigated the biodiversity and antifouling activity of fungi in soft corals Cladiella krempfi and Sarcophyton tortuosum from the South China Sea. A high diverse and abundant fungal community was found in the two soft corals. Furthermore, five isolates shared 83-95% similarity with their closest relatives, indicating that they might be novel species in genera Phaeoshaeria and Mucor. In addition, approximately 50% of the representative isolates exhibited distinct antifouling activity. In particular, isolates Fungal sp. SCAU132 and Fungal sp. SCAU133 displayed very strong antifouling activity against Bugula neritina, suggesting they can provide a potential resource for further investigation on isolation of novel antifouling metabolites. To our knowledge, this study is the first report to investigate the biodiversity and antifouling activity of fungi in C. krempfi and S. tortuosum.

Marine unsaturated fatty acids: structures, bioactivities, biosynthesis and benefits.

Unsaturated fatty acids (UFAs) are an important category of monounsaturated and polyunsaturated fatty acids with nutritional properties. These secondary metabolites have been obtained from multitudinous natural resources, including marine organisms. Because of the increasing numerous biological importance of these marine derived molecules, this review covers 147 marine originated UFAs reported from 1978 to 2018. The review will focus on the structural characterizations, biological properties, proposed biosynthetic processes, and healthy benefits mediated by gut microbiota of these marine naturally originated UFAs.

Nutritional characteristics of marine fish Sardinella zunasi Bleeker and immunostimulatory activities of its glycoprotein.

Sardinella zunasi Bleeker, an edible and medicinal marine fish, is largely distributed in tropical oceans. However, the chemical composition and nutritional properties of this species have not yet been investigated. In the present study, proximate composition, fatty acids, amino acids, taurine, and minerals of S. zunasi Bleeker were characterized, and the immunostimulatory properties of its glycoprotein were evaluated. The results indicated the presence of crude protein (19.66%), crude lipid (6.29%) and carbohydrate (0.74%) in S. zunasi Bleeker; monounsaturated fatty acids and polyunsaturated fatty acids in the fatty acid composition of S. zunasi Bleeker were 25.00% and 31.01%, respectively; S. zunasi Bleeker was rich in taurine (219 mg/100 g) and essential amino acids (5.57 g/100 g). In addition, the glycoprotein of S. zunasi consisted of protein and sugars, with a total content of 34.25% and 16.27%, respectively. The glycoprotein showed significant effects on promoting NO, TNF-α and IL-6 in a dose-dependent manner in RAW264.7 macrophage cells. Thus, these findings provide a scientific basis for the further utilization of glycoprotein from S. zunasi Bleeker.

Nocardioides kandeliae sp. nov., an endophytic actinomycete isolated from leaves of Kandelia candel.

A Gram-stain-positive, aerobic, non-spore-forming, atrichous and short rod-shaped endophytic actinomycete, designated strain BGMRC 2075T, was isolated from the leaves of Kandelia candel, and was subjected to polyphasic characterization to unravel its taxonomic position. Phylogenetic analyses based on 16S rRNA gene sequences indicated that strain BGMRC 2075T belongs to the genus Nocardioides ,showing the highest 16S rRNA gene sequence similarity to Nocardioides aestuarii JC2056T (96.1 %), Nocardioides agariphilus MSL-28T (95.1 %) andNocardioides islandiensis MSL-26T (95.1 %). The predominant cellular fatty acids of strain BGMRC 2075T were iso-C16 : 0, C17 : 1ω8c and C17 : 0. The major menaquinone was MK-8(H4). The diagnostic diamino acid in the cell-wall peptidoglycan was ll-2,6-diaminopimelic acid. The predominant cell-wall sugars were composed of ribose and glucose. The polar lipid pattern contained diphosphatidylglycerol, phosphatidylglycerol, phosphatidylmethylethanolamine, phosphatidylcholine, five unknown phospholipids, one phospholipid of unknown structure containing glucosamine, and an unknown polar lipid. The DNA G+C content was 70.8 mol%. All these data support the allocation of the novel strain to the genus Nocardioides. The results of physiological and biochemical characterization allow the phenotypic differentiation of strain BGMRC 2075T from N. aestuarii JC2056T, N. agariphilus MSL-28T and N. islandiensis MSL-26T. Strain BGMRC 2075T represents a novel species of the genus Nocardioides, for which we propose the name Nocardioides kandeliae sp. nov. The type strain is BGMRC 2075T (=KCTC 39886T=DSM 104480T).

Investigation of glycerol concentration on corn starch morphologies and gelatinization behaviours during heat treatment.

The effects of various glycerol concentrations (0%, 5%, 10%, 20%, and 50%, w/w) on the morphologies and gelatinization behaviours of corn starch were evaluated by confocal laser scanning microscopy (CLSM), scanning electron microscopy (SEM), differential scanning calorimetry (DSC) and rapid visco-analyzer (RVA). When corn starch granules with no added glycerol were treated at 65°C, the granules of corn starch were almost completely broken and tightly connected, and the characteristic birefringence of the starch granules disappeared. Various microscopic techniques revealed that starch gelatinization was delayed to higher temperatures as the glycerol concentration increased. In the presence of glycerol-water systems (5%, 10%, 20%, and 50%, w/w), the peak temperatures of corn starch increased by 1.6°C, 7.4°C, 10.7°C, and 19.7°C, respectively, compared to corn starch in water. The RVA pasting profiles showed that the gelatinization temperature increased as the glycerol concentration increased, which was consistent with polarized light microscope observations and DSC tests.