Determination of Glucosamine in Raw Materials and Dietary Supplements Containing Glucosamine Sulfate and/or Glucosamine Hydrochloride by High-Performance Liquid Chromatography with FMOC-Su Derivatization: Collaborative Study

A collaborative study was conducted for determination of glucosamine in raw materials and dietary supplements containing glucosamine sulfate and/or glucosamine hydrochloride by high-performance liquid chromatography (HPLC) with N-(9-fluorenyl-methoxycarbonyloxy) succinimide (FMOC-Su) derivatization. Thirteen blind materials, one pair of which were duplicates, were tested by 12 collaborating laboratories. The test samples consisted of various commercial products, including tablets, capsules, drink mix, and liquids as well as raw materials, blanks, and those for spike recovery analyses. The tests with blank products and products spiked with glucosamine showed good specificity of the method. The average recoveries at spike levels of 100 and 150% of the declared amount were 99.0% with a relative standard deviation (RSD) of 2.1%, and 101% with an RSD of 2.3%, respectively. The test results between laboratories on each commercial product were reproducible with RSD values of no more than 4.0%, and the results were repeatable in the same laboratory with an average RSD of 0.7%. HorRat values ranged from 0.5 to 1.7 on both tests of spike recovery and reproducibility between laboratories on commercial products. The average determination coefficient of the calibration curves from the laboratories was 0.9995 with an RSD of 0.03%. All of the 12 collaborating laboratories succeeded in the study and none of their reported test results were outliers, partly indicating the robustness of the method. It is recommended that the method be accepted by AOAC INTERNATIONAL as Official First Action.

Pulp Stem Cell-Mediated Functional Pulp Regeneration

The preservation of vital dental pulp with vasculature and nerve components remains one of the most significant challenges in modern dentistry. Due to the immense potential for neurovascularization, mesenchymal stem cell (MSC) transplantation has shown emerging promise in regenerative medicine and dental translational practice. Actually, pulp mesenchymal stem cells, including postnatal dental pulp stem cells (from permanent teeth) and stem cells from human exfoliated deciduous teeth, possess unique properties based on their origins from neural crest or glial cells. Furthermore, they reside in a neurovascular niche and have the potential for neurogenesis, angiogenesis, and neurovascular inductive activity. According to current pulp regeneration strategies, pulp stem cell-mediated approaches to regeneration have demonstrated convincing evidence that they can rebuild the complex histologic structure of native pulp in situ with highly organized physiologic patterns or even achieve de novo regeneration of complete dental pulp tissues. More importantly, recent clinical studies emphasized in situ neurovascularization outcomes in successful regeneration of vitalized pulp via pulp stem cell transplantation. In this review, we summarize recent breakthroughs in pulp stem cell-mediated pulp regeneration, emphasizing the crucial achievement of neurovascularization. This functional pulp regeneration represents an innovative and promising approach for future regenerative endodontics.

VPS34 stimulation of p62 phosphorylation for cancer progression

Vps34, a class III PtdIns3 lipid kinase involved in the control of both autophagic and endocytic systems, has been studied extensively in numerous fundamental cellular processes. Accumulating evidence indicates that Vps34 may also contribute to the development and progression of human cancers. However, the mechanism of Vps34 in tumorigenesis remains elusive. Here, we report an unanticipated role of Vps34 in the activation of p62 for cancer development. We identified that Vps34 is a transcriptional activator of p62 through competition of Nrf2 (nuclear factor erythroid 2-related factor 2) for Keap1 binding. Vps34 augments the association of PKC-δ with p62 for its phosphorylation at Serine 349, which leads to positive feedback on the Nrf2-dependent transcription of oncogenes. Additionally, we found that the expression of Vps34 is correlated with the tumorigenic activity of human breast cancer cells. Normally inactive in breast cancer, caspase 8 can cleave Vps34 at residue D285, which directly abolished its lipid kinase activity and dramatically altered cell invasion potential, colony formation, as well as tumorigenesis in orthotopic engraftments in mice. The cleavage at D285 blocks expression of LC3-II, Nrf2 and subsequently, p62, in addition to blocking tumor growth, indicating that the intact structure of Vps34 is essential for its activity. Moreover, either knockout of PKC-δ or knockdown of p62 by small interfering RNA in MCF-7 cells abrogates Vps34-dependent tumor growth. Data presented here suggested that Vps34 stimulates tumor development mainly through PKC-δ- activation of p62.

Force-Induced H2S by PDLSCs Modifies Osteoclastic Activity during Tooth Movement

Hydrogen sulfide (H₂S), a gasotransmitter, has been recently linked to mesenchymal stem cell (MSC) function and bone homeostasis. Periodontal ligament stem cells (PDLSCs) are the main MSCs in PDL, which respond to mechanical force to induce physiological activities during orthodontic tooth movement (OTM). However, it is unknown whether mechanical force might induce endogenous H₂S production by PDLSCs to regulate alveolar bone homeostasis. Here, we used a mouse OTM model to demonstrate that orthodontic force-induced endogenous H₂S production in PDL tissue was associated with macrophage accumulation and osteoclastic activity in alveolar bone. Then, we showed that mechanical force application induced cystathionine β-synthase (CBS) expression and endogenous H₂S production by PDLSCs. Moreover, blocking endogenous H₂S or systemically increasing H₂S levels could decrease or enhance force-induced osteoclastic activities to control tooth movement. We further revealed how force-induced H₂S production by PDLSCs contributed to the secretion of monocyte chemoattractant protein-1 (MCP-1) and the expression of receptor activator of nuclear factor-κB ligand/osteoprotegerin (RANKL/OPG) system by PDLSCs. The secretion and expression of these factors controlled macrophage migration and osteoclast differentiation. This study demonstrated that PDLSCs produced H₂S to respond to and transduce force signals. Force-induced gasotransmitter H₂S production in PDLSCs therefore regulated osteoclastic activities in alveolar bone and controlled the OTM process through the MCP-1 secretion and RANKL/OPG system.

PDL Progenitor–Mediated PDL Recovery Contributes to Orthodontic Relapse

Periodontal ligament (PDL) is subjected to mechanical force during physiologic activities. PDL stem/progenitor cells are the main mesenchymal stem cells in PDL. However, how PDL progenitors participate in PDL homeostasis upon and after mechanical force is largely unknown. In this study, force-triggered orthodontic tooth movement and the following relapse were used as models to demonstrate the response of PDL progenitors and their role in PDL remodeling upon and after mechanical force. Upon orthodontic force, PDL collagen on the compression side significantly degraded, showing a broken and disorganized pattern. After force withdrawal, the degraded PDL collagen recovered during the early stage of relapse. Correspondingly, increased CD90+ PDL progenitors with suppressed expression of type I collagen (Col-I) were observed upon orthodontic force, whereas these cells accumulated at the degradation regions and regained Col-I expression after force withdrawal during early relapse. Our results further showed that compressive force altered cell morphology and repressed collagen expression in cultured PDL progenitors, which both recovered after force withdrawal. Force withdrawal–induced recovery of collagen expression in cultured PDL progenitors could be regulated by transforming growth factor–β (TGF-β), a key molecule for tissue homeostasis and extracellular matrix remodeling. More interesting, inhibiting the regained Col-I expression in CD90+ PDL progenitors by blocking TGF-β interrupted PDL collagen recovery and partially inhibited the early relapse. These data suggest that PDL progenitors can respond to mechanical force and may process intrinsic stability to recover to original status after force withdrawal. PDL progenitors with intrinsic stability are required for PDL recovery and consequently contribute to early orthodontic relapse, which can be regulated by TGF-β signaling.

Effects of ambient PM2.5 on pathological injury, inflammation, oxidative stress, metabolic enzyme activity, and expression of c-fos and c-jun in lungs of rats

Fine particulate matter (PM2.5) exposure is associated with morbidity and mortality induced by respiratory diseases and increases the lung cancer risk. However, the mechanisms therein involved are not yet fully clarified. In this study, the PM2.5 suspensions at different dosages (0.375, 1.5, 6.0, and 24.0 mg/kg body weight) were respectively given to rats by the intratracheal instillation. The results showed that PM2.5 exposure induced inflammatory cell infiltration and hyperemia in the lung tissues and increased the inflammatory cell numbers in bronchoalveolar lavage fluid. Furthermore, PM2.5 significantly elevated the levels of pro-inflammatory mediators including tumor necrosis factor-α (TNF-α), interleukin (IL)-6, IL-1β, and intercellular adhesion molecule 1 (ICAM-1) and the expression of c-fos and c-jun in rat lungs exposed to higher dose of PM2.5. These changes were accompanied by decreases of activities of superoxide dismutase and increases of levels of malondialdehyde, inducible nitric oxide synthase, nitric oxide, cytochrome P450s, and glutathione S-transferase. The results implicated that acute exposure to PM2.5 induced pathologically pulmonary changes, unchained inflammatory and oxidative stress processes, activated metabolic enzyme activity, and enhanced proto-oncogene expression, which might be one of the possible mechanisms by which PM2.5 pollution induces lung injury and may be the important determinants for the susceptibility to respiratory diseases.

Seroprevalence and risk factors for Toxoplasma gondii in sheep and goats in Jinzhou, Northeastern China

In the present study, serum samples from 402 sheep and 216 goats were collected from 5 counties in Jinzhou from August to October 2012 and antibodies to Toxoplasma gondii were detected by modified agglutination test (MAT). Overall, 104 (16.8%) had antibodies to T. gondii with antibody titres of 1:25 to 1:800. Seropositive samples were distributed in all the 5 counties and seroprevalences of T. gondii varied significantly with flock size, age and rearing system, but not with breed, gender and farm location. The seroprevalences in small farms (18.3%, 95/518, 95% confidence interval [CI], 15.0-21.7%) were statistically higher than that in large farms (9%, 9/100, 95% CI, 3.4-14.6%) (P < 0.05), older animals were statistically higher than that in younger animals (P < 0.01). The prevalence in extensively and semi intensively raised samples was statistically higher than that in intensively raised animals (P < 0.01). Small flock size and extensive rearing system are the potential risk factors for the prevalence of Toxoplasma infection in sheep and goats in Jinzhou. This is the first report of T. gondii infection in sheep and goats in Jinzhou, northeastern China, and of an association of seropositivity to T. gondii and the risk factors.

T Cells Are Required for Orthodontic Tooth Movement

The immune system plays a pivotal role during bone remodeling process. Orthodontic tooth movement (OTM) induces local inflammation in periodontium, but whether systemic immune response is involved in OTM remains unknown. In this study, we show that tooth movement distance was significantly reduced in T-cell-deficient immunocompromised mice compared with wild-type (WT) mice. Intravenous infusion of allogeneic T cells to the immunocompromised mice rescued the OTM distance. Correspondingly, increased numbers of tartrate-resistant acid phosphatase (TRAP)-positive osteoclasts were detected around the alveolar bone after OTM in WT mice but were barely detected in immunocompromised mice. Moreover, intravenous infusion of T cells rescued the number of TRAP-positive osteoclasts in the OTM area of the immunocompromised mice, thus suggesting T cells are required for OTM. We then reveal that OTM induced a significant elevation of type 1 T helper cell (Th1) cytokines tumor necrosis factor-α (TNF-α) and interferon-γ (IFN-γ) around periodontal tissue in WT but not in immunocompromised mice. Infusion of T cells could increase the levels of TNF-α and IFN-γ in periodontal tissues of immunocompromised mice. More interestingly, intraperitoneal injection of TNF-α inhibitor etanercept significantly reduced the distance of OTM in T-cell-infused immunocompromised mice. In summary, this study demonstrates a previously unrecognized mechanism that T cells are required for OTM depending on Th1-associated cytokines.

Orthodontic Force Induces Systemic Inflammatory Monocyte Responses

Periodontal inflammation and alveolar bone remodeling during orthodontic tooth movement are considered regional reactions. However, how systemic immune responses are involved in this regional reaction remains unclear. In this study, we explored the systemic effects of orthodontic force by focusing on the mononuclear phagocyte system. Flow cytometric analysis showed that the percentage of inflammatory monocytes, in peripheral blood and in the monocyte reservoir spleen, decreased on days 1 and 3 and then recovered on day 7 after force application. Along with the systemic decrease of inflammatory monocyte percentage, the number of tartrate-resistant acid phosphatase–positive osteoclasts increased in the compression side of the periodontal tissue during orthodontic tooth movement. Systemic transfusion of enhanced green fluorescent protein–labeled inflammatory monocytes showed recruitment of these monocytes to the orthodontic force compression side of periodontal tissues. These monocytes were colocalized with tartrate-resistant acid phosphatase–positive osteoclasts. In vivo and in vitro experiments showed that orthodontic force could upregulate the expression of pivotal monocyte chemokine monocyte chemotactic protein 1 in periodontal tissues or cultured periodontal ligament cells, which may contribute to monocyte recruitment to regional sites. These data suggest that orthodontic force induces systemic immune responses related to inflammatory monocytes and that systemic inflammatory monocytes can be recruited to periodontal tissues by orthodontic force stimulus.

M1-like Macrophage Polarization Promotes Orthodontic Tooth Movement

Macrophages play a crucial role in inflammatory-mediated bone loss. Orthodontic tooth movement (OTM) is associated with inflammatory bone remodeling. However, whether and how macrophages contribute to mechanical force–induced OTM remains unknown. In this study, we hypothesized that polarization of M1-like macrophages may contribute to the OTM. Orthodontic nickel-titanium springs were applied to the upper first molars of rats or mice to induce OTM. The distance of OTM gradually increased after mechanical force was applied to the rats for 5 and 10 d. M1-like macrophage polarization and expression of M1 cytokine tumor necrosis factor (TNF)-α also increased after force application. More importantly, monocyte/macrophage depletion in mice by injection of clodronate liposomes decreased the distance of OTM and the number of tartrate-resistant acid phosphatase (TRAP)–positive osteoclasts and CD68+ macrophages, accompanied by reduced expressions of M1 markers TNF-α and inducible nitric oxide synthase (iNOS), whereas systemic transfusion of M1 macrophages in mice increased them. Further experiments showed that injection of recombinant TNF-α increased the distance of OTM and the number of TRAP-positive osteoclasts and CD68+ macrophages, as well as upregulated the expression of TNF-α and iNOS. Blockage of TNF-α by etanercept injection reduced the distance of OTM and the number of TRAP-positive osteoclasts and CD68+ macrophages, as well as decreased the levels of TNF-α and iNOS. These data suggest that M1-like macrophage polarization promotes alveolar bone resorption and consequent OTM after mechanical force application.

Mitochondrial damage: an important mechanism of ambient PM2.5 exposure-induced acute heart injury in rats

Epidemiological studies suggested that ambient fine particulate matter (PM2.5) exposure was associated with cardiovascular disease. However, the underlying mechanism, especially the mitochondrial damage mechanism, of PM2.5-induced heart acute injury is still unclear. In this study, the alterations of mitochondrial morphology and mitochondrial fission/fusion gene expression, oxidative stress, calcium homeostasis and inflammation in hearts of rats exposed to PM2.5 with different dosages (0.375, 1.5, 6.0 and 24.0mg/kg body weight) were investigated. The results indicated that the PM2.5 exposure induced pathological changes and ultra-structural damage in hearts such as mitochondrial swell and cristae disorder. Furthermore, PM2.5 exposure significantly increased specific mitochondrial fission/fusion gene (Fis1, Mfn1, Mfn2, Drp1 and OPA1) expression in rat hearts. These changes were accompanied by decreases of activities of superoxide dismutase (SOD), Na(+)K(+)-ATPase and Ca(2+)-ATPase and increases of levels of malondialdehyde (MDA), inducible nitric oxide synthase (iNOS) and nitric oxide (NO) as well as levels of pro-inflammatory mediators including TNF-α, IL-6 and IL-1β in rat hearts. The results implicate that mitochondrial damage, oxidative stress, cellular homeostasis imbalance and inflammation are potentially important mechanisms for the PM2.5-induced heart injury, and may have relations with cardiovascular disease.

Enhanced M1/M2 macrophage ratio promotes orthodontic root resorption

Mechanical force-induced orthodontic root resorption is a major clinical challenge in orthodontic treatment. Macrophages play an important role in orthodontic root resorption, but the underlying mechanism remains unclear. In this study, we examined the mechanism by which the ratio of M1 to M2 macrophage polarization affects root resorption during orthodontic tooth movement. Root resorption occurred when nickel-titanium coil springs were applied on the upper first molars of rats for 3 to 14 d. Positively stained odontoclasts or osteoclasts with tartrate-resistant acid phosphatase were found in resorption areas. Meanwhile, M1-like macrophages positive for CD68 and inducible nitric oxide synthase (iNOS) persistently accumulated on the compression side of periodontal tissues. In addition, the expressions of the M1 activator interferon-γ and the M1-associated pro-inflammatory cytokine tumor necrosis factor (TNF)-α were upregulated on the compression side of periodontal tissues. When the coil springs were removed at the 14th day after orthodontic force application, root resorption was partially rescued. The number of CD68(+)CD163(+) M2-like macrophages gradually increased on the compression side of periodontal tissues. The levels of M2 activator interleukin (IL)-4 and the M2-associated anti-inflammatory cytokine IL-10 also increased. Systemic injection of the TNF-α inhibitor etanercept or IL-4 attenuated the severity of root resorption and decreased the ratio of M1 to M2 macrophages. These data imply that the balance between M1 and M2 macrophages affects orthodontic root resorption. Root resorption was aggravated by an enhanced M1/M2 ratio but was partially rescued by a reduced M1/M2 ratio.

Effect of sulfur dioxide on inflammatory and immune regulation in asthmatic rats

BACKGROUND

Exposure to sulfur dioxide (SO2) increases asthma risk. Inflammatory and immune responses are typical in asthma disease. The exact effect of SO2 on modulation of the inflammatory and immune responses in asthmatic rats remains unclear.

OBJECTIVES

Here we sought to investigate the molecular mechanisms underlying the NF-κB inflammatory pathway and the Th1/Th2 imbalance in asthmatic rats exposed to SO2.

METHODS

Male Wistar rats were challenged by ovalbumin (OVA) or SO2 alone or together, and then mRNA and protein levels of some inflammatory and immune genes were measured. NF-κB nuclear translocation was analyzed. Bronchoalveolar lavage (BAL), inflammatory cell counts and histopathologic examination were performed.

RESULTS

(1) OVA plus SO2 induced abnormal pathological changes and inflammatory responses in lung relative to exposure to OVA alone; (2) showing NF-κB nuclear translocation and activation through up-regulating IKKβ mRNA and protein expression and down-regulating IκBα expression in the presence of OVA or OVA plus SO2; (3) OVA plus SO2 significantly raised TNF-α and IL-6 levels in BALF compared with the OVA group; (4) SO2 markedly elevated IL-4 levels and decreased IFN-γ levels in BALF in the asthmatic rats, stimulating IgE generation which was closely related to inhibiting the expression of Foxp3, a specific marker of regulatory T cells.

CONCLUSIONS

SO2 affects the airway inflammatory and immune responses of the asthmatic rats and enhances the susceptibility to OVA by aggravating inflammatory responses in lungs, up-regulating pro-inflammatory cytokine expression, and causing the Th1/Th2 imbalance, which might contribute to the increased risk of asthma disease.

Force-induced Adrb2 in periodontal ligament cells promotes tooth movement

The sympathetic nervous system (SNS) regulates bone resorption through β-2 adrenergic receptor (Adrb2). In orthodontic tooth movement (OTM), mechanical force induces and regulates alveolar bone remodeling. Compressive force-associated osteoclast differentiation and alveolar bone resorption are the rate-limiting steps of tooth movement. However, whether mechanical force can activate Adrb2 and thus contribute to OTM remains unknown. In this study, orthodontic nickel-titanium springs were applied to the upper first molars of rats and Adrb1/2(-/-) mice to confirm the role of SNS and Adrb2 in OTM. The results showed that blockage of SNS activity in the jawbones of rats by means of superior cervical ganglion ectomy reduced OTM distance from 860 to 540 μm after 14 d of force application. In addition, the injection of nonselective Adrb2 agonist isoproterenol activated the downstream signaling of SNS to accelerate OTM from 300 to 540 μm after 7 d of force application. Adrb1/2(-/-) mice showed significantly reduced OTM distance (19.5 μm) compared with the wild-type mice (107.6 μm) after 7 d of force application. Histopathologic analysis showed that the number of Adrb2-positive cells increased in the compressive region of periodontal ligament after orthodontic force was applied on rats. Mechanistically, mechanical compressive force upregulated Adrb2 expression in primary-cultured human periodontal ligament cells (PDLCs) through the elevation of intracellular Ca(2+) concentration. Activation of Adrb2 in PDLCs increased the RANKL/OPG ratio and promoted the peripheral blood mononuclear cell differentiation to osteoclasts in the cocultured system. Upregulation of Adrb2 in PDLCs promoted osteoclastogenesis, which accelerated OTM through Adrb2-enhanced bone resorption. In summary, this study suggests that mechanical force-induced Adrb2 activation in PDLCs contributes to SNS-regulated OTM.

A simple and novel method for GII norovirus genome clone with generic primers

AIMS

This study aims to establish a novel method for cloning GII norovirus genome using generic primers rationally designed based on multiple alignments of 96 GII norovirus genome sequences.

METHODS AND RESULTS

Based on conservative analysis of 96 GII norovirus genome sequences available in GenBank, three fragments encompassing the full-length genome were rationally designed. Fragments A, B and C were amplified by primers N1F/N2819R, N2689F/COG2R and COG2F/adaptor, respectively. Meanwhile, the sensitivity of the novel primers was evaluated, which could achieve 10(1) RTPCRU, as determined by the common detection primer pair JV12/JV13. The availability of the novel protocol was verified by sequencing two norovirus strains with different genotypes.

CONCLUSIONS

Primers for GII norovirus genome clone were rationally designed, and a novel GII genome clone method was established.

SIGNIFICANCE AND IMPACT OF THE STUDY

The three-fragment cloning method can be used as a universal tool to collect information on the genome of norovirus strains for future evolution and antivirus studies.

Development of monoclonal antibody-coated immunomagnetic beads for separation and detection of norovirus (genogroup II) in faecal extract samples

AIMS

The aim of this study is to develop an RT-PCR assay combined with immunomagnetic beads (IMS/RT-PCR) coating monoclonal antibody (Mab) for separation and detection of norovirus (genogroup II) in faecal samples. We furthermore compare its detection limits with IMS/RT-PCR using polyclonal antibody (Pab) and the TRIzol extraction method followed by RT-PCR (TRIzol-RT-PCR).

METHODS AND RESULTS

Mab-coated beads and Pab-coated beads were added to a series of tenfold dilutions of faecal extract containing norovirus in 1 ml PBS. After incubation and collection, the RNA was released by heating from virus separated by beads. The tenfold dilutions of faecal were also extracted with TRIzol reagent. The RNA was used as the template for RT-PCR detection (primers: JV12-JV13). IMS/RT-PCR using Mab showed an endpoint in the 10(-7) dilution and was 10(2) times more sensitive than IMS/RT-PCR using Pab and was at least 10(3) times more sensitive than TRIzol-RT-PCR method.

CONCLUSIONS

IMS/RT-PCR using Mab proved to be a more sensitive method of noroviruses (NVs) detection than IMS/RT-PCR using Pab and the TRIzol-RT-PCR method.

SIGNIFICANCE AND IMPACT OF THE STUDY

This is the first study to detect NVs with IMS/RT-PCR using Mab, and could serve as a model for future assays when broadly reactive NVs-specific Mabs are developed.

[Study on the inclusions of xindonin A-beta-cyclodextrin and xindonin B-beta-cyclodextrin]

The inclusions compounds of Xindonin A-beta-cyclodextrin and Xindonin B-beta-cyclodextrin were prepared by the liquid-phase method in aqueous solution. They were confirmed by thin layer chromatography, differential thermal analysis and specific rotation. Changes of ultraviolet spectrum were determined. The composition ratios of inclusion compounds were obtained by the continuous variation method. Solubility of the inclusions were determined.

Factors influencing the synthesis of monoester and diester from polyethylene glycol400 and oleic acid by lipase

Factors influencing the synthesis of mono- and diester of polyethylene glycol400 (PEG400) oleate with immobilized lipase from Candida sp.1619 as biocatalyst were investigated. Mono- and diester were formed with different molar ratios of the substrates after reacting for 6 hours. The amount of monoester to diester formed was in the range of 3.5:1 to 4.1:1 when the molar ratio of acid to PEG400 was 0.25:1 to 2:1. Almost equal amounts of mono- and diesters were produced when the molar ratio of acid to PEG400 was 3:1 to 8:1. When the equilibrium of reaction was reached (22 hours), only diester was found in the reaction mixture with different molar ratio of substrates. The amount of monoester to diester was 1:3.2 in the reaction system containing hexane, even the molar ratio of acid to PEG400 was 2:1.

[Enzymatic synthesis of saccharide and saccharide alcohol fatty acid esters]

Conditions for esterification in tert-butanol using fatty acid as acy1 donor and saccharides or saccharide alcohols as acy1 acceptors, immobilized lipase from Candida sp. 1619 as biocatalyst were investigated. Optimal temperature and pH for esterication were 40 degrees C-45 degrees C and 5.5-7.5, respectively. Among the 13 acy1 donors compared, the best ones are the linoleic acid and oleic acid. The similar conversion degree was obtained when using saturated fatty acids with carbon chain length from C8 to C22. Among the 23 saccharides and saccharide alcohols compared, D-fructose, D-Xylose, trehalose, D-sorbitol, xylitol, mannitol isopropyidoneglucofruranose and alpha-methylglucopyranoside showed much higher esterification degree than other acy1 acceptors. In addition, the reaction degree of saccharide alcohols were substantially higher than that of the corresponding saccharides. The conversion was enhanced greatly when the molar ratio of acy1 donor to acy1 acceptor was higher than 2 to 1. In the case of using sorbitol and loeic acid as substrates, the reaction was carried out in 100 ml conical flask and the reaction system consisted of 3.0 mmol oleic acid(0.85 g), 0.2 mmol sorbitol(0.036 g), 3 mL tert-butanol, 30 mg immobilized lipase(600 u), shaken at 40 degrees C. After reaction for 48 h, more than 90% of sorbitol was esterified based on equal molar of substrates. The products were identified TLC as monoester and diester.

[Study on the inclusion of oridonin-beta-cyclodextrin]

The inclusion compound of Oridonin-beta-cyclodextrin was prepared by the liquid-phase method in aqueous solution. And it was confirmed by thin layer chromatography, differential thermal analysis and specific rotation. The change (A) of ultraviolet spectrum was determined. The composition ratio of inclusion compound between Oridonin and beta-CD was obtained by the continuous variation method.

Rapid extraction and high-performance liquid chromatographic determination of parthenolide in feverfew (Tanacetum parthenium)

A rapid and sensitive method for quantifying parthenolide in feverfew herb (Tanacetum parthenium) was developed that is significantly faster than those reported in the literature. The extraction system consisted of acetonitrile/water (90:10, v/v) in a bottle with stirring for 30 min. Both Soxhlet and bottle-stirring extractions were studied. Samples were analyzed using high-performance liquid chromatography with a Cosmosil C18-AR column (150 x 4.6 mm, 5 microm, 120 A). The mobile phase consisted of acetonitrile/water (55:45, v/v) with a flow rate of 1.5 mL/min and UV detection at 210 nm. Analysis time was 6 min, with a detection limit of 0.10 ng on column. The calibration curve was linear over a range of 0.160-850 microg/mL parthenolide with R(2) = 0.9999. Replicate tests indicated good reproducibility of the method with an RSD% = 0.88 (n = 10). Spike recovery of parthenolide was found to be 99.3% with an RSD% = 1.6 (n = 6).

[Study on the inclusion of isodoniol-beta-cyclodextrin]

The inclusion compound of isodoniol-beta-cyclodextrin was prepared by the liquidphase method in aqueous solution. And it was confirmed by thinlayer chromatography, differentical thermal analysis and specific rotation. The change (delta A) of ultraviolet spectrum was determined. The composition ratio of the inclusion compound between isodoniol and beta-CD was obtained by the continuous variation method.

Polyethylene glycol400 laurate synthesized by immobilized lipase in a solvent-free system

Conditions for the esterification of polyethylene glycol400 (PEG400) with lauric acid by immobilized lipase from Candida sp. 1619 in a solvent-free system were investigated. The esterification degree was increased greatly through the dehydration that occurred during the reaction. When the amount of lauric acid added exceeded the stoichiometric amount the yield of product was further improved by fed-batch feeding of PEG400. In the reaction system that was composed of 5.0 mmol of lauric acid, 2.5 mmol of PEG400, 20 mg of immobilized lipase (200 u), 0.2 ml of water, at 40 degrees C shaken for 48 h in a 100-ml conical flask without a plug, the esterification degree of 98.9% was reached. When the amount of lauric acid used was increased to 60 mmol, the PEG400 in reaction system was completely esterified. The recovery yield of product was 95% by hexane extraction and the product was identified as diester by means of TLC.

[The preparation and properties of catechol-1,2-dioxygenase from Pseudomonas putida]

Catechol-1,2-dioxygenase (EC 1.13.11.1) catalyzes the degradation of catechol to cis, cis-muconic acid. The biochemical properties of catechol-1,2-dioxygenase from Pseudomonas putida 84103 were investigated. The optimum pH and temperature is 7.5-8.0 and 25-30 degrees C, respectively. Cu2+, Zn2+ inhibit the enzyme activity. The paper chromatograph and UV absorption spectrum of enzymatic reaction product are accordance with those of the standard muconic acid.