Synthesis, characterization, and biological activity of selenium nanoparticles conjugated with polysaccharides.

Nanoparticles with unique properties have potential applications in food, medicine, pharmacology, and agriculture industries. Accordingly, many significant researches have been conducted to develop novel nanoparticles using chemical and biological techniques. This review focuses on the synthesis of selenium nanoparticles (SeNPs) using polysaccharides as templates. Various instrumental techniques being used to confirm the formation of polysaccharide-SeNPs conjugates and characterize the properties of nanoparticles are also introduced. Finally, the biological activities of the synthesized SeNPs and the influence of structural factors of polysaccharides on the property of synthetic nanocomposites are highlighted. In general, the polysaccharides functionalized SeNPs can be easily obtained using sodium selenite as precursor and ascorbic acid as reductant. The final products having different particle size, morphology, and selenium content exhibit abundant physiological activities. Structural factors of polysacchairdes involving molecular weights, substitution of functional groups, and chain conformation play determinant roles on the properties of nanocomposites, resulting in different biological performances. The review on the achievements and current status of polysaccharides conjugated SeNPs provides insights into this exciting research topic for further studies in the future.

A highly efficient Ziehl-Neelsen stain: identifying de novo intracellular Mycobacterium tuberculosis and improving detection of extracellular M. tuberculosis in cerebrospinal fluid.

Tuberculous meningitis leads to a devastating outcome, and early diagnosis and rapid chemotherapy are vital to reduce morbidity and mortality. Since Mycobacterium tuberculosis is a kind of cytozoic pathogen and its numbers are very few in cerebrospinal fluid, detecting M. tuberculosis in cerebrospinal fluid from tuberculous meningitis patients is still a challenge for clinicians. Ziehl-Neelsen stain, the current feasible microbiological method for the diagnosis of tuberculosis, often needs a large amount of cerebrospinal fluid specimen but shows a low detection rate of M. tuberculosis. Here, we developed a modified Ziehl-Neelsen stain, involving cytospin slides with Triton processing, in which only 0.5 ml of cerebrospinal fluid specimens was required. This method not only improved the detection rate of extracellular M. tuberculosis significantly but also identified intracellular M. tuberculosis in the neutrophils, monocytes, and lymphocytes clearly. Thus, our modified method is more effective and sensitive than the conventional Ziehl-Neelsen stain, providing clinicians a convenient yet powerful tool for rapidly diagnosing tuberculous meningitis.

[Feasibility study of preserving intercostobrachial nerve during dissection for breast carcinoma: evidences from a preliminary pathologic exploration].

OBJECTIVE: To determine the feasibility of preservation of intercostobrachial nerve (ICBN) in breast cancer. METHODS: During June 2004 to June 2006, 99 patients with operable breast cancer receiving an axillary lymph node dissection at our department were analyzed. The extirpated ICBN and ambient tissues were tested by HE staining to observe the pathological changes. RESULTS: In 96 (96.97%) cases with ICBN sacrificing, the nerves were not violated microscopically and the nerve cells remained intact. Of 28 patients with axillary lymphadenectasis, only 3 cases (10.71%) were found to have tumor emboli in the peri-neural vessels. CONCLUSION: The preservation of ICBN is a feasible and safe technique. The operative approach should be advocated. If at all possible, a surgeon should identify ICBN and preserve it.

Comparative study on glucomannans with different structural characteristics: Functional properties and intestinal production of short chain fatty acids.

Glucomannans (GMs) from abundant natural resources have excellent processing properties and plentiful bioactivities. In current study, functional properties of GMs with different structural characteristics, including KGM from konjac, DOP from dendrobium, AGP40, ASP-4N, ASP-6N, & ASP-8N from aloe were determined. Results suggested that molecular weights (Mw) of GMs were positively correlated with their water absorption capacity, fat absorption capacity, and viscosity, while ratio of mannose/glucose showed negative effect. Higher degree of acetylation (DA) mainly corresponded to higher values of solubility and ζ-potential. Then, effects of the six GMs on general health status, serum biochemicals, and intestinal SCFAs production in mice were evaluated in vivo. Analysis of general health status and levels of serum biochemicals revealed that mice with consecutive supplementation of GMs for 14 days performed normally compared with those in control group. Interestingly, the productions of SCFAs (mainly acetate and butyrate) in the cecal and colonic contents were significantly promoted. Generally, higher concentrations of SCFAs were produced when mice were treated with GMs having higher Mw, ratio of glucose, and DA. The current investigation suggested that both functional and intestinal fermentation property of GMs were jointly determined by the monosaccharide composition, molecular weight, and degree of acetylation.

Structure identification of α-glucans from Dictyophora echinovolvata by methylation and 1D/2D NMR spectroscopy.

Dictyophora echinovolvata is a kind of edible mushroom in the Dictyophora genus, of which polysaccharide is an important chemical substance. Herein, three polysaccharide fractions (DEP-4P, DEP-6P and DEP-8P) were prepared from water extract of D. echinovolvata using gradient ethanol precipitation method. Their chemical structures were analyzed by methylation analysis and 1D/2D NMR spectroscopy. Molecular weights were determined by multi-angle laser light scattering combined with size-exclusion chromatography (HPSEC-MALLS). HPSEC data showed that DEP-4P had the highest values of molecular weight, intrinsic viscosity and hydrodynamic radius. DEP-6P and DEP-8P had lower molecular weights, which contributed to their easily distinguished 1D and 2D NMR spectra. Methylation and NMR analysis suggested that the three fractions were linear α-(1 → 4)-glucans with α-Glcp residues linked to the backbone at C-6. Differences among the three fractions were the molar ratios of the identified glycosidic bonds. Repeating units of polysaccharides from D. echinovolvata were proposed as follows.

Protective effect of three glucomannans from different plants against DSS induced colitis in female BALB/c mice.

Glucomannans (GMs) from diverse natural plants have great potentiality in enhancing the host immune system. The protective effects of three GMs on the intestinal mucosal immunity in colitis mice were investigated and compared in this study. The three GMs (KGM, AGP, and DOP) were obtained from Amorphophallus rivieri, Aloe vera, and Dendrobium officinale, respectively, having different weight-averaged molecular weights (Mw), acetyl group content, and molar ratios of mannose to glucose (M/G). The three fractions were administered with or without dextran sodium sulfate (DSS) containing drinking water. Macroscopic observations (health state, crypt depth, and bowel thickness of colon tissue) were conducted. Furthermore, related cytokines and mRNA expressions of TLRs were measured by ELISA and RT-qPCR, respectively. Results showed that the administration of the three GMs improved the health state of colitis mice, such as the recovery of body weight, and the increase of the immune organ index, crypt depth, bowel wall thickness, and total number of immune cells. The integrity of intestinal mucosa was maintained by the increased number of goblet cells and mucin protein production. Further studies showed that GMs kept the balance between pro- and anti-inflammatory cytokines and also regulated the expressions of TLR-2, TLR-4, TLR-6, and TLR-9. The above results suggested that GMs could attenuate the intestinal epithelial injury and regulate the intestinal mucosal immunity. Structural features including the M/G ratio, Mw, and the content of acetyl groups jointly influence the protective effects of GMs on the colitis mice.

Structural and conformational characterization of linear O-acetyl-glucomannan purified from gel of Aloe barbadensis Miller.

Aloe barbadensis Miller (Aloe vera) is a kind of popular medicinal and horticultural crops widely cultivated around the world. Polysaccharides with different structural features and bioactivities have been isolated from the pulp of Aloe vera. In the current study, a novel polysaccharide fraction (AGP40) isolated and purified from gel juice of Aloe vera was subjected to structural and conformational analysis. AGP40 had a backbone consisting of major →4)-ß-Manp-(1 → residues and minor →3)-ß-Manp-(1 → and →4)-ß-Glcp-(1 → residues. Low degree of branches distributed at O-6 of 4-linked mannose in the main chain. The acetyl groups in AGP40 presented as mono- or di-substituents (O-2, O-3, O-6, O-2,3, O-2,6 and O-3,6). AGP40 performed as random coil conformation in 0.1 M NaNO3 solution, and had fibrous filaments and irregular spherical structures in solid state. Detailed structural and conformational analysis of AGP40 in the present study may greatly improve the bioactive function investigation and mechanism explanation of acetyl glucomannans in the future.

Effect of Zn2+ on halohydrin dehalogenase expression and accumulation through multi-parameter correlation research with Escherichia coli P84A/MC1061.

Using 5 Zn2+ supplementation strategies in a 50 L batch bioreactor named FUS-50L(A), possible correlations among Zn2+ content and addition timing, physiologic activity (PA), halohydrin dehalogenase (HheC) accumulation of Escherichia coli P84A/MC1061 were systematically investigated. First, Zn2+ was confirmed as the significant factor, and its optimal concentration for HheC expression was 3.87 mg/L through fermentation experiments in shaking flasks. Second, based on experimental results from the different strategies, it was found that PA, nutrient consumption rate (NCR) and specific growth rate (µ) for E. coli P84A/MC1061 were promoted in the log phase (4-8 h) under appropriate Zn2+ concentrations in the lag phase and late log phase. Furthermore cell biomass was also increased to a higher level and the maximum HheC activity (i.e. HheCmax) was increased by 9.80%, and the time to reach HheCmax was reduced from 16 to 12 hours. Furthermore, appropriate supplementation of Zn2+ caused higher µ for E. coli P84A/MC1061, which resulted in more rapid accumulation of increased acetic acid concentrations, leading to higher acetic acid consumption avoiding any negative effects on producing HheC because of carbon source being exhausted prematurely and acetic acid being consumed rapidly.

[Synergistic effect of physical and Chironomus plumosus combined disturbance on regeneration and transformation of internal phosphorus].

To explain the synergistic effect of physical and Chironomus plumosus combined disturbance on the regeneration and transformation of internal phosphorus, laboratory static incubation experiments were carried out with the sediments and overlying water from a eutrophic river in Suzhou. Rhizon samplers were used to acquire the pore water. In the experiment, we compared the variation of different phosphorus forms in the overlying water, the pore water and sediments under the Chironomus plumosus disturbance and the combined disturbance. The results indicated that the amount of different forms of phosphorus (TP, PP, DTP, DIP) in the overlying water under combined disturbance was higher than that under Chironomus plumosus combination disturbance. It was attributed to the significant increase of the microbial activity in the sediments. Compared with Chironomus plumosus disturbance, the amount of DIP and ferrous decreased with the greater magnitude and range. It was attributed to the superposition effect of the physical and benthos disturbance on the penetration depth of the dissolved oxygen. In addition, the amount of NH4C1-P decreased remarkably in the 0-2 cm sediment while Fe/Al-P increased obviously. Furthermore, the variation magnitude of NH4Cl-P and Fe/Al-P was higher under combined disturbance than that under Chironomus plumosus disturbance, which suggested the superposition effect of the physical and benthos disturbance on the regeneration and migration of phosphorus.

[Response of Sediment Micro Environment and Micro Interface to Physical Disturbance Intensity Under the Disturbance of Chironomus plumosus].

The response of sediment micro environment and micro intertace to physical disturbance intensity under the physical and Chironomus plumosus disturbance was investigated by means of sediment Rhizon samplers and Unisense micro sensor system. The sediment and overlying water were taken from Meiliang bay of Taihu Lake. The results showed that the OPD reached up to 12.1 mm under the high intensity (240 r · min(-1)), while it was higher than 3. 8. mm under low intensity (60 r · min(-1)). The TOE, the difference of TOE and DOE, OPD, ORP and the difference of DO spatial distribution were all positively correlated with the physical disturbance intensity. The increasing magnitude and range of pH as well as the decreasing magnitude and range of ferrous followed the same response tendency. Within the 0-6 cm sediment, the water content and porosity as well as the microbial activity at the same depth increased with the increase of physical disturbance intensity. In addition, the degree of response of the above parameters to the physical disturbance intensity was weakened with the increase of sediment depth. It was suggested that Chironomus plumosus dug more and deeper galleries under high intensity physical disturbance. Therefore, the sediment micro environment and micro interface were transformed in the vertical direction of the sediment.

[Effects of cold-shock on tomato seedlings under high temperature stress].

High temperature stress (HTS) is one of the major limiting factors that affect the quality of intensively cultured seedlings in protected facilitates during hot season. Increasing the cross adaptive response of plant induced by temperature stress is an effective way to improve plant stress resistance. In order to explore the alleviating effect of cold-shock intensity on tomato seedlings under HTS, tomato seedlings were subjected to cold-shock treatments every day with 5 °C, 10 °C, and 15 °C for 10 min, 20 min, and 30 min, respectively, in an artificial climate chamber. The effect of single appropriate cold-shock on the gene expression of small heat shock proteins LeHSP 23.8 and CaHSP18 was investigated. The results showed that hypocotyl elongation and plant height of tomato seedlings were restrained by cold-shock treatment before HTS was met. The alleviating effect of tomato seedlings under HTS by cold-shock varied greatly with levels and durations of temperature. The membrane lipids in the leaf of tomato seedlings were subjected to peroxidation injury in the cold-shock treatment at 5 °C, in which the penetration of cell membrane was increased and the activities of antioxidant enzyme was inhibited. The alleviating effect to HTS by cold-shock was decreased with the increasing cold-shock duration at 10 °C, however, a reverse change was found at 15 °C. The results indicated that cross adaptive response of tomato seedling could be induced with a moderate cold-shock temperature for a proper duration before HTS was met. The optimum cold-shock treatment was at 10 °C for 10 min per day, under which, the dry mass, healthy index, activities of protective enzymes (including SOD, POD and CAT) in leaves of tomato seedlings were significantly increased, the contents of proline and soluble protein were enhanced, relative conductivity and malondialdehyde concentration were significantly decreased, and the expression levels of Le-HSP23.8 and CaHSP18 were increased compared with that under normal temperature condition.

Effect of low-dose fenvalerate on semen quality capacitation in adult mice.

BACKGROUND: Fenvalerate (FEN) has been demonstrated to be a reproductive toxicant in humans and rodents. However, little is known about whether short-term exposure to low-dose FEN produces reproductive toxicity. METHODS: We administered FEN (0.009 375, 0.1875, 3.750, or 45.00 mg×kg(-1)×d(-1) by gavage for 30 days) to male ICR mice and compared reproductive toxicity parameters between groups receiving different concentrations of FEN. Reproductive toxicity was evaluated by computer-assisted semen quality analysis (CASA), chlortetracycline (CTC) assay, and histopathology. RESULTS: The sperm morphology and testis histology of FEN-exposed mice (all doses) were similar to that in controlling mice. Exposure to FEN at a concentration of 0.1875 mg×kg(-1)×d(-1) decreased sperm path straightness (STR) and linearity (LIN) (both P < 0.05), but had no significant impact on average path velocity (VAP), straight line velocity (VSL), curvilinear velocity (VCL), lateral amplitude (ALH), beat cross frequency (BCF), or progressive motility (MOT). FEN reduced the rate of mouse sperm capacitation in a dose-dependent manner. CONCLUSION: The present results demonstrate that exposure to low-dose FEN for 30 days reduces semen quality and sperm capacitation in adult mice.

[Canonical correspondence analysis between phytoplankton community and environmental factors in winter and summer in shallow lakes of plain river network areas, Suzhou].

Field investigations on the phytoplankton community were carried out in December 2005 and June 2006 in shallow lakes of plainriver network areas, Suzhou City. Results show that there are 73 species, 62 genus, 8 phylum phytoplankton, which is mainly composed of the Chlorophyta, Bacillariophyta and Cyanophyta. In winter, the average phytoplankton abundance is 254.88 x 10(4) cells x L(-1), and the Bacillariophyta abundance accounts for 62.3% of the total. While in summer, the average phytoplankton abundance is 2704.28 x 10(4) cells x L(-1), and the Cyanophyta abundance accounts for 93.5%. The relationship between 62 genus of phytoplankton and 11 environmental factors from 57 sampling sites in research area was studied by Canonical Correspondence Analysis. It suggests that water temperature, permanganate indexes, nitrate nitrogen and total nitrogen are the main environmental factors correlated with the distribution of phytoplankton community. And in winter, pH, ammonia nitrogen and total phosphorus are also the main environmental factors. Furthermore, the Bacillariophyta has higher adaptability to the changeable environment. The Chlorophyta can tolerate higher concentration of permanganate indexes, phosphorus nutrients, nitrogen nutrients and total organic carbon, whereas the response of Cyanophyta to environmental factors needs further research.