Significant enhancement in antioxidant and antimicrobial activity of tragacanth gum through chemical modification using amino acids.

Herein, glutamic acid, lysine, arginine and glycine grafted tragacanth gum (TG) were synthesized and designated as TG-Glu, TG-Lys, TG-Arg, and TG-Gly, respectively. The corresponding degrees of substitution (DS) were 0.212, 0.255, 0.394, and 0.169. Thermal, antioxidant, and antibacterial properties of synthesized amino acid-grafted tragacanth gum (ATG) were investigated. The results suggested that the grafting of amino acids onto TG has the potential to alter its thermal properties. When compared with TG and amino acid alone, ATG exhibited significantly enhanced antioxidant and antibacterial properties, with these properties being concentration-dependent. At a concentration of 2 mg/mL for TG-Glu and 3 mg/mL for TG-Arg, TG-Gly, and TG-Lys, the scavenging rate for 2,2'-hypoazido-3-ethylbenzothiazoline sulfonate (ABTS) radical reached 100 %. On the other hand, the scavenging rate of TG-Glu for hydroxyl radical achieved 100 % even at a concentration as low as 1 mg/mL. These properties were accompanied by an increase in reducing force and a notable improvement in the ability to scavenge superoxide anion (O2-). Moreover, the combination of amino acids and TG represents a promising approach to enhance the antimicrobial activities of TG, with the bacteriostatic rate reaching 100 %. Consequently, ATG shows promise as a novel agent for both antioxidation and antimicrobial applications.

Advances in sulfonated modification and bioactivity of polysaccharides.

Polysaccharides, as biological macromolecules, are widely found in plants, animals, fungi, and bacteria and exhibit various biological activities. However, many natural polysaccharides exhibit low or non-existent biological activities because of their high molecular weights and poor water solubility, limiting their application in many fields. Sulfonation is one of the most effective chemical modification methods to improve physicochemical properties and biological activities of natural polysaccharides or even impart natural polysaccharides with new biological activities. Therefore, sulfonated polysaccharides have attracted increasing attention because of their antioxidant, anticoagulant, antiviral, and immunomodulatory properties. This paper reviews the recent advances in the sulfonation of polysaccharides, including preparation, characterization, and biological activities of sulfonated polysaccharides, and provides a theoretical basis for wide applications of sulfonated polysaccharides.

The RagA GTPase protects young egg chambers in Drosophila.

The preservation of female fertility under unfavorable conditions is essential for animal reproduction. Inhibition of the target of rapamycin complex 1 (TORC1) is indispensable for Drosophila young egg chamber maintenance under nutrient starvation. Here, we show that knockdown of RagA results in young egg chamber death independent of TORC1 hyperactivity. RagA RNAi ovaries have autolysosomal acidification and degradation defects, which make the young egg chambers sensitive to autophagosome augmentation. Meanwhile, RagA RNAi ovaries have nuclear-localized Mitf, which promotes autophagic degradation and protects young egg chambers under stress. Interestingly, GDP-bound RagA rescues autolysosome defects, while GTP-bound RagA rescues Mitf nuclear localization in RagA RNAi young egg chambers. Moreover, Rag GTPase activity, rather than TORC1 activity, controls Mitf cellular localization in the Drosophila germ line. Our work suggests that RagA separately controls autolysosomal acidification and Mitf activity in the Drosophila young egg chambers.

[The regulatory relationship between RagA and Nprl2 in Drosophila gut development].

The gastrointestinal tract is the largest digestive organ and the largest immune organ and detoxification organ, which is vital to the health of the body. Drosophila is a classic model organism, and its gut is highly similar to mammalian gut in terms of cell composition and genetic regulation, therefore can be used as a good model for studying gut development. target of rapmaycin complex 1 (TORC1) is a key factor regulating cellular metabolism. Nprl2 inhibits TORC1 activity by reducing Rag GTPase activity. Previous studies have found that nprl2 mutated Drosophila showed aging-related phenotypes such as enlarged foregastric and reduced lifespan, which were caused by over-activation of TORC1. In order to explore the role of Rag GTPase in the developmental defects of the gut of nprl2 mutated Drosophila, we used genetic hybridization combined with immunofluorescence to study the intestinal morphology and intestinal cell composition of RagA knockdown and nprl2 mutated Drosophila. The results showed that RagA knockdown alone could induce intestinal thickening and forestomach enlargement, suggesting that RagA also plays an important role in intestinal development. Knockdown of RagA rescued the phenotype of intestinal thinning and decreased secretory cells in nprl2 mutants, suggesting that Nprl2 may regulate the differentiation and morphology of intestinal cells by acting on RagA. Knockdown of RagA did not rescue the enlarged forestomach phenotype in nprl2 mutants, suggesting that Nprl2 may regulate forestomach development and intestinal digestive function through a mechanism independent of Rag GTPase.

Influence of transient intraocular pressure elevation during laser in situ keratomileusis on rabbit retina thickness.

AIM: To utilize tissue micro measurement to study the effect of transient high intraocular pressure (IOP) induced by different durations of suction during laser in situ keratomileusis (LASIK) on rabbit retina thickness. METHODS: Sixty healthy New Zealand white rabbits were randomly divided into a control group, and 3 negative-pressure suction groups (20s group, 45s group, and 3min group) and each group was comprised of 15 rabbits (30 eyes); the latter 3 groups were the transient high IOP models. The retinal tissue around the papilledema was separated. Hematoxylin and eosin (HE) staining was carried out to generate slices for light microscopy. The changes in the retina thickness values of each layer were measured for all animals in each group at different postoperative recovery periods and compared with the values recorded for the animals in the control group. The thickness of the retinal tissue showed a normal distribution. The ANOVA was performed by using SPSS13.0 statistic software. RESULTS: In the comparison between the 20s and 45s negative-pressure suction groups and the control group, no significant differences were observed, except at 14d. Significant difference was observed between the 3min negative-pressure suction group and the control group, and the retina thickness value of each layer reached a peak at 14d after repair. CONCLUSION: Conventional negative suction during LASIK may not lead to significant changes in retinal tissue thickness; however, if the suction duration is increased to 3min, it will cause significant changes in retinal tissue thickness.

Orthogonal Supramolecular Polymer Formation on Highly Oriented Pyrolytic Graphite (HOPG) Surfaces Characterized by Scanning Probe Microscopy.

Formation of an orthogonal supramolecular polymer on a highly oriented pyrolytic graphite (HOPG) surface was demonstrated for the first time by means of scanning probe microscopy (SPM). Atomic force microscopy (AFM) was employed to characterize the variation of both the thickness and the topography of the film formed from (1) monomer 1, (2) monomer 1/Zn(2+), and (3) monomer 1/Zn(2+)/cross-linker 2, respectively. Scanning tunneling microscopy (STM) was used to monitor the self-assembly behavior of monomer 1 itself, as well as 1/Zn(2+) ions binary system on graphite surface, further testifying for the formation of linear polymer via coordination interaction at the single molecule level. These results, given by the strong surface characterization tool of SPM, confirm the formation of the orthogonal polymer on the surface of graphite, which has great significance in regard to fabricating a complex superstructure on surfaces.

[Preparation and Characterization of Quinone Functional Polymer Biocarrier (PET-AQS) for Biodenitrification Catalysis].

Anthraquinone sodium sulfonate (AQS) was immobilized on polyethylene terephthalate (PET) by chemical synthesis, forming quinone functional polymer biocarrier (PET-AQS), and its characteristics in biodenitrification catalysis were analyzed. Quinone group was demonstrated to be successfully immobilized on the surface of the polymer and the concentration of immobilized quinone was 0.140 6 mmol x g(-1) by Attenuated Total Reflectance Spectrometry (ATR-IR) and Energy Dispersive Spectrometry (EDS). The PET-AQS could accelerate biodenitrification. The relationship between the denitrification rate constant (K(x)) and the PET-AQS concentration (C(PET-AQS)) obeyed the pseudo-zero order kinetics. After ten rounds of recycling in the biodenitrification system with approximately 0.056 2 mmol quinone, the denitrification rate was kept at more than 1.2 times of the blank system. This indicated that PET-AQS exhibited a good operational stability and was beneficial to practical application.

[Preparation and application of the quinonyl chloromethylation polystyrene in biological treatment of wastewater].

The technology of non-water-soluble mediator anaerobic biological catalysis has attracted more and more attention in the field of environment technology. In this study, five kinds of quinonly compounds were grafted on the chloromethylation polystyrene macromolecular carrier by Friedel-Crafts reaction. Reaction factors of temperature and molar ratio for the 1,4-naphthoquinone grafting carrier were optimized, and the optimal temperature was 78 degreesC while the optimal molar ratio of 1, 4-naphthoquinone and chloromethylation polystyrene was 2: 1. Fourier infrared spectrum analysis confirmed that the quinone groups were successfully grafted on the macromolecular backbone chloromethylation polystyrene. Catalysis using the five kinds of quinonly materials as non-water-soluble redox mediators enhanced the biological denitrification rate and the decoloration of azo dyes, meanwhile these materials showed good reusability in the biodegradation of azo dye. This study developed a new method for the preparation of quinonly materials and revealed a new field in the technology of mediator catalysis.

Comparison of treatments for bullous keratopathy in rabbits.

The aim of the present study was to compare deep lamellar endothelial keratoplasty (DLEK) and penetrating keratoplasty (PK) treatments for bullous keratopathy (BK). In total, 36 healthy New Zealand white rabbits were randomly divided into 3 groups termed the experimental, DLEK and PK groups. The experimental control group received no treatment. The DLEK and PK groups were observed for corneal astigmatism at 1, 2, or 3 months post-surgery using a corneal topography instrument and a slit lamp microscope. The incidence of immune rejection after 3 months of recovery was determined using hematoxylin and eosin (H&E) staining. The corneal specimens from the surgery groups were compared with those from the control group. In the 12 rabbit eyes that underwent the DLEK surgery, the central cornea became clear after 1 week. After 3 months, these corneas were almost transparent and no eye infections or other complications were observed in 10 of the eyes, while surgical perforations in 2 eyes led to surgical lamellar failure. In the PK surgery group, in which 12 rabbit eyes were also treated, nine were almost transparent after 3 months of recovery, while three eyes were immunologically rejected due to the corneal grafts. The occur-rences of corneal astigmatism that were observed following DLEK and PK treatment were significantly different after 1, 2 and 3 months of recovery (P<0.05). Normal corneal staining was observed in the DLEK and PK rabbits subjected to H&E staining after 3 months of recovery. A BK animal model was established by curetting the Descemet's membrane (DM film). In comparison with PK, DLEK is a superior surgical treatment for BK.

[Study on gene expression profiles of rabbit retina transient IOP during LASIK].

OBJECTIVE: To detect the changes of gene expression profiles of retina by way of gene chip technology, and to investigate possible molecular pathogenesis of RGCs apoptosis caused by transient high IOP. METHODS: Twenty-two new Zealand white rabbits were randomized to experimental control and negative pressure suction 3 min groups. The rabbit were executed at different time points of post-LASIK, such as postoperative instant, 7 d, 10 d, then the total RNA of retinal tissue was extracted to detect gene expression profiles by the way of Agilent rabbit one-way gene chip. RESULTS: Instant after negative pressure suction, the genes differential expressed had 704 genes. Of these, the expression of 485 genes were unregulated and 219 genes down regulated. The higher expression of apoptosis genes were CRYAA, CRYAB, TLR3 and KRT18. 7 d after negative pressure suction, the genes differential expressed had 482 genes. Of these, the expression of 178 genes were unregulated and 304 genes down regulated. The higher expression of apoptosis genes were CRYAB, IL1-BETA and IL1R1. 10 d after negative pressure suction, the genes differential expressed had 402 genes. Of these, the expression of 213 genes were unregulated and 189 genes down regulated. The higher expression of apoptosis genes were CRYAB, CRYBA3, CRYBB2, IL1-BETA and IL1R1. CONCLUSION: The gene expression had changed after negative pressure suction. The genes with higher fold change protected RGCs from apoptosis.

Research on Influences of Transient High IOP during LASIK on Retinal Functions and Ultrastructure.

Objectives. To study the influences of transient high intraocular pressure(IOP) during LASIK on retinal functions and ultrastructure. Methods. Thirty-two New Zealand white rabbits were randomly divided into normal control, experimental control, negative suction 20 s and negative suction 3 min groups. The experimental control group was treated only by laser. Rabbit eyes received suction for different periods of time (20 s, 3 min) by negative pressure generator in different groups. The changes of neuro-optic and retinal ultrastructure were observed under electron and light microscopes; retinal neurofunctional changes were observed with flash-visual evoked potential (F-VEP) and flash-electroreinogram (F-ERG). Results. There was no obvious change in optic nerve, retina, ERG a-wave and b-wave in normal control and experimental control groups. There were slight changes in tissues of optic nerve and retina at various times of suction 20 s compared with control group, and a sharp change in suction 3 min group within 14d after operation, but these changes recovered at 28d . Amplitude of ERG b-wave observed at different time will decrease with suction periods prolonged. It can recover to normal level with the prolonged recovery periods. Amplitude and incubation period of ERG a-wave and VEP-P did not change significantly after different duration of suction. Conclusions. The transient high IOP during LASIK might have influence on retinal function and ultrastructure, but these changes were reversible.

Adsorption of heavy metal ions from aqueous solution by crosslinked carboxymethyl konjac glucomannan.

Crosslinked carboxymethyl konjac glucomannan (CMKGM) with degrees of substitution (DS) 0.265 and 0.550 were prepared through reaction of monochloroacetic acid (MCA), konjac glucomannan (KGM) and epichlorohydrin and used to adsorb Cu(2+), Pb(2+) and Cd(2+) ions from the aqueous solutions. Regardless of the metal ion species, the adsorption capacity rapidly reached equilibrium within 20min and adsorption followed second-order kinetic equation. The effect of pH on adsorption was apparent, the appropriate range was 5-6. The adsorptions of three metal ions are well followed as the Langmuir adsorption isotherm. The maximum adsorption capacity (Q(m)) and Langmuir constant (b) of CMKGM (DS=0.550) for Pb(2+) were 41.7mg/g and 0.305mg/L. These values were higher than those for Cu(2+) and Cd(2+). Among the tested ions, the order of adsorption capacity was Pb(2+)>Cu(2+)>Cd(2+) in mass basis. The regeneration study indicates that CMKGM could be used repeatedly without significantly changing their adsorption capacities and desorption percentage.

[IR study on the thermal decomposition IR of the cationic fenugreek gum].

The title complexes shown as cationic fenugreek gum were prepared. The thermal decomposition process of fenugreek gum and cationic fenugreek gum was studied quantitatively by means of thermogravimetric analysis an dinfrared spectroscopic measurement of samples after heating at different temperatures. Additionally, according to the fact that the absorbance peak changes and theanalysis of TG-IR of cationic fenugreek gum at different temperatures, it can be drawn that the thermal decomposition of the cationic fenugreek gum might lead to a possible thermal-cracking process.