A new strategy of using periphyton to simultaneously promote remediation of PAHs-contaminated soil and production of safer crops.

Contaminated farmland leads to serious problems for human health through biomagnification in the soil-crop-human chain. In this paper, we have established a new soil remediation strategy using periphyton for the production of safer rice. Four representative polycyclic aromatic hydrocarbons (PAHs), including phenanthrene (Phe), pyrene (Pyr), benzo[b]fluoranthene (BbF), and benzo[a]pyrene (BaP), were chosen to generate artificially contaminated soil. Pot experiments demonstrated that in comparison with rice cultivation in polluted soil with ΣPAHs (50 mg kg-1) but without periphyton, adding periphyton decreased ΣPAHs contents in both rice roots and shoots by 98.98% and 99.76%, respectively, and soil ΣPAHs removal reached 94.19%. Subsequently, risk assessment of ΣPAHs based on toxic equivalent concentration (TEQ), pollution load index (PLI), hazard index (HI), toxic unit for PAHs mixture (TUm), and incremental lifetime cancer risk (ILCR) indicated that periphyton lowered the ecological and carcinogenicity risks of PAHs. Besides, the role of periphyton in enhancing the rice productivity was revealed. The results indicated that periphyton alleviated the oxidative stress of PAHs on rice by reducing malondialdehyde (MDA) content and increasing total antioxidant capacity (T-AOC). Periphyton reduced the toxic stress of PAHs on the soil by promoting soil carbon cycling and metabolic activities as well. Periphyton also improved the soil's physicochemical properties, such as the percentage of soil aggregate, the contents of humic substances (HSs) and nutrients, which increased rice biomass. These findings confirmed that periphyton could improve rice productivity by enhancing soil quality and health. This study provides a new eco-friendly strategy for soil remediation and simultaneously enables the production of safe crops on contaminated land.

Insecticidal and acetylcholine esterase inhibition activity of Rhododendron thymifolium essential oil and its main constituent against two stored product insects.

In this work, we investigated the bioactivities of the essential oil (EO) extracted from the Rhododendron thymifolium and its principal germacrone against Lasioderma serricorne and Tribolium castaneum. The EO was obtained by steam distillation. Germacrone was obtained by cryogenic crystallization. The bioactivity of EO and germacrone was tested via contact and repellent activity assays. The results showed that EO and germacrone possessed contact and repellent activities against two species of insects. EO exhibited obvious contact activity against the L. serricorn adults, larvae and T. castaneum larvae with LD50 values of 29.15 µg/adult, 42.73 µg/larva, 19.65 µg/larva respectively. Germacrone exhibited excellent contact activity against the L. serricorne adults, larvae and the T. castaneum larvae with LD50 values of 17.18 µg/adult, 20.94 µg/larva, 20.93 µg/larva respectively. And at the highest testing concentrations (78.63 and 15.73 nL/cm2), the repellent activity of EO and germacrone on two target insects was comparable to that of the positive control (DEET) after 30 h exposure. In especially, in the treatment of the 120 h after the repellent activity of EO and germacrone against T.castaneum adults and larvae were still very significant and showed the same level percentage repellency as DEET. Meanwhile, germacrone exhibited inhibition of acetylcholinesterase activity with IC50 values of 3%. The results indicated that the EO of R. thymifolium and germacrone had the potential to be developed as natural insecticides and repellents for the control of T. castaneum and L. serricorne.

Cytotoxic p-terphenyls from the deep-sea-derived Aspergillus candidus.

From the deep-sea-derived fungus Aspergillus candidus, one novel (1) and three known (2-4) p-terphenyl derivates were isolated. The structure of the new compound was established mainly on the basis of extensive analysis of 1D and 2D NMR data. All four isolates were tested for in vitro anti-food allergic and antitumor bioactivities. Compounds 3 and 4 showed potent antiproliferative effect against four cancer cells of Hela, Eca-109, Bel-7402, and PANC-1 with IC50 values ranging from 5.5 µM to 9.4 µM.

Effects of plant growth regulators on transient expression of foreign gene in Nicotiana benthamiana L. leaves.

BACKGROUND: In the last decades, replicating expression vectors based on plant geminivirus have been widely used for enhancing the efficiency of plant transient expression. By using the replicating expression vector derived from bean yellow dwarf virus and green fluorescent protein as a reporter, we investigated the effects of α-naphthalene acetic acid, gibberellins3, and 6-benzyladenine, as three common plant growth regulators, on the plant biomass and efficiency of transient expression during the process of transient expression in Nicotiana benthamiana L. leaves. RESULTS: With the increase of the concentration of α-naphthalene acetic acid, gibberellins3, and 6-benzyladenine (from 0.1 to 1.6 mg/L), the fresh weight, dry weight, and leaf area of the seedlings increased first and then returned to the levels similar to the controls (without chemical treatment). The treatment with α-naphthalene acetic acid at 0.2 and 0.4 mg/L can enhance the level of transient expression of green fluorescent protein, which peaked at 0.4 mg/L α-naphthalene acetic acid and was increased about by 19%, compared to the controls. Gibberellins3 at 0.1-0.4 mg/L can enhance the level of transient expression of green fluorescent protein, which peaked at 0.2 mg/L gibberellins3 and was increased by 25%. However, the application of 6-benzyladenine led to decrease in the level of transient expression of green fluorescent protein. CONCLUSIONS: The appropriate plant growth regulators at moderate concentration could be beneficial to the expression of foreign genes from the Agrobacterium-mediated transient expression system in plants. Thus, appropriate plant growth regulators could be considered as exogenous components that are applied for the production of recombinant protein by plant-based transient expression systems.

Systematic analysis of the metabolites of Angelicae Pubescentis Radix by UPLC-Q-TOF-MS combined with metabonomics approaches after oral administration to rats.

Angelicae Pubescentis Radix (APR) is a typical Traditional Chinese Medicine (TCM) and has been widely used to treat rheumatism and headache diseases in China. This research aimed to illustrate the metabolites of APR in vivo to lay a foundation for the clinics application. A UPLC-Q-TOF-MS method combined with metabonomics approaches is used to address this objective. The separation was achieved on an Agilent SB-C18 column (1.8 µm, 2.1 × 50 mm) with a gradient elution system (ACN and 0.1 % formic acid-water). An electrospray ionization (ESI) was used for mass spectrometer and operated in a full-scan mode at m/z 100 - 800. The data were collected in the positive ion mode and analyzed by the Masslynx 4.1 and SIMCA 13.0 software. Furthermore, an orthogonal partial least-squares discriminant analysis (OPLS-DA) using SIMCA 13.0 software was applied to investigate the differences between the blank and drug groups in bio-samples of rats (plasma, urine, feces). Totally 213 compounds including 41 prototype ingredients, 107 phase I and 65 phase II metabolites were detected, according to the MS and MS/MS data. Among them, 134 metabolites are potential new compounds.

Systematic analysis of the metabolites of Angelol B by UPLC-Q-TOF-MS after oral administration to rats.

Angelicae Pubescentis Radix (APR), a widely used traditional Chinese medicine (TCM), is mainly used to treat rheumatism and headache diseases. Angelol B is one of the bioactive constituents of APR with significant anti-inflammatory activity. This paper is aimed to illustrate the metabolites of angelol B in vivo. To achieve this objective, a metabolomics approach based on a rapid and accurate UPLC-Q-TOF-MS method was used to detect the metabolites of Angelol B in rat. A gradient elution system (ACN and 0.1% formic acid water) equipped with an Agilent SB-C18 column (1.8 µm, 2.1 mm × 50 mm) to complete the separation. Scanning area at m/z 100.800 operated on an electrospray ionization (ESI). The data were collected in both positive and negative ion mode and analyzed by the Masslynx 4.1 and SIMCA 13.0 software. A total of 31 metabolites including 20 phase I and 11 phase II. metabolites were identified. Their structure and fragmentation process were deduced based on the MS and MS/MS data. All of thirty-one metabolites are new compounds based on the search of SCI-Finder database.

[Regulation of extracellular ATP onchlorophyll content and fluorescence characteristics of Angelica sinensis seedlings under drought and low temperature stress].

As an important signal molecule, extracellular ATP(eATP) can regulate many physiological and biochemical responses to plant stress. In this study, the regulation of extracellular ATP(eATP) on chlorophyll content and chlorophyll fluorescence parameters of Angelica sinensis seedlings were studied under drought and low temperature stress. The results showed that all the chlorophyll content, the actual photochemical efficiency [Y(Ⅱ)], the electron transfer rate(ETR), the photochemical quenching coefficient(qP and qL) of A. sinensis leaves were significantly decreased under drought and low temperature stress, respectively. At the same time, non-photochemical quenching(NPQ and qN) were also all significantly increased, respectively. The application of eATP alleviated the decrease of chlorophyll content, Y(Ⅱ), ETR, qP and qL of A. sinensis leaves under drought and low temperature stress, and eliminated the increase of qN and NPQ. The results indicated that eATP could effectively increase the open ratio of PSⅡ reaction centers, and improve the electron transfer rate and light energy conversion efficiency of PSⅡ of A. sinensis leaves under drought and low temperature stress. It is beneficial to enhance the chlorophyll synthesis and the adaptability of PSⅡ about A. sinensis seedlings to drought and low temperature stress.

Urbanization threaten the pollination of Gentiana dahurica.

With rapid spread of the urbanization, many environmental factors, such as climate, soil pH and nutrients have been changed. However, the plant pollination affected by urbanization was seldom conducted. Here, we studied the flower visitation rates, seed production, pollen limitation and flower morphological characters of Gentiana dahurica at 3 populations along an urban-peri-urban gradient around Xi'ning over 4 consecutive years, aiming to test the effects of urbanization on plant pollination service. Our results showed that the pollinator visit frequencies, interannual stability of pollinator assemblages and visit frequencies declined with the intensification of urbanization. As urbanization intensified, plant borne more flowers and the flower morphological sizes became "longer" (the length of flowers, filaments and styles were increased, but the width of flowers kept stable at the 3 populations); the flower duration, especially the female phase duration prolonged. The seed-set ratio of G. dahurica in natural condition decreased and more severe pollen limitation occurred in more urbanized populations. Also, an interannual variation of seed-set ratio and index of pollen limitation (IPL), which related with the variation of pollinator visit frequencies, were found in this study. These results suggest that the pollination service can be threatened by urbanization over a long-time interval for G. dahurica. This finding highlights the importance of pollinator affections acting on plant pollination system. Additionally, as pollinator assemblages and visit frequencies interannually changed, a long-time scale observation is needed to understand the plant-pollinator relationships.

Extracellular ATP released by copper stress could act as diffusible signal in alleviating the copper stress-induced cell death.

In the present work, by using tobacco cell suspension and wheat seedlings, we studied that eATP (extracellular ATP) released by copper (Cu) stress could act as diffusible signal in alleviating the Cu stress-induced cell death. A semipermeable membrane was fixed in the middle of a plastic box to divide the box into two equal compartments (A and B, respectively). This semipermeable membrane can prevent direct cell-to-cell (or seedling-to-seedling) contact and the diffusion of the macromolecules [such as ATPase (adenosine 5'-triphosphatase)] between these two compartments. The cell suspension directly stressed with CuCl2 was placed in compartment A and was incubated with the untreated cell suspension in compartment B. Such treatment significantly increased the levels of cell death and eATP content of the cell suspension in these two compartments. In contrast, addition of ATPase into the cell suspension directly stressed with CuCl2 decreased the eATP level in these two compartments but further increased the level of cell death in compartment B, compared to no addition of ATPase. Similar results were obtained when tobacco cell suspension was replaced by wheat seedlings. These observations indicate that when Cu stress from compartment A induced the plant cell death in compartment B, ATP transferred from compartment A could play a role in alleviating this cell death. Thus, it is suggested that eATP released by copper stress could act as diffusible signal in alleviating the Cu stress-induced cell death.

[Physiological effects of cadmium stress on Astragalus membranaceus seedlings and alleviative effects of attapulgite clay on cadmium stress].

In this study we investigate the effects of cadmium stress on Astragalus membranaceus seedlings and the alleviative effects of attapulgite clay in growth substrate on cadmium stress to A. membranaceus seedlings. The results showed that the Y (Ⅱ) (effective photochemical quantum yield of PSⅡ photosynthetic), qP(photochemical quenching coefficient), ETR(the rate of non-cyclic electrontransport through PSⅡ), and chlorophyll content of the leaves were significantly decreased with the increase of cadmium concentrations, while the cadmium content, non-photochemical quenching(NPQ, qN) of the leaves and cadmium content, MDA content, plasma membrane permeability, and the damage degree of root apical membrane of the roots were significantly increased. Simultaneously, the activities of APX(ascorbate peroxidase), SOD(superoxide dismutase), POD(peroxidase), CAT(catalase), soluble protein content, and soluble sugar content of roots were increased first but then decreased with the increasing cadmium concentration. Under the condition of without Cd stress, the attapulgite clay into the growth substrate did not significantly affect above physiological indexes of leaves, but significantly increased SOD activity and soluble sugar content of roots and decreased the MDA content, damage degree of root apical membrane of roots, while other physiological indexes did not significantly change. Under cadmium stress, the presence of attapulgite clay in the growth substrate significantly alleviated the cadmium-induced decreases Y (Ⅱ), qP, ETR and chlorophyll content of leaves, and the CAT activity, soluble protein content, and soluble sugar content of roots. Under condition with cadmium stress, the presence of attapulgite clay significantly alleviated the cadmium-induced increases of leaves cadmium content, qN and NPQ, and the cadmium content, MDA content, plasma membrane permeability, damage degree of root apical membrane, SOD, POD, and APX activity of the roots. And, the alleviative effects of attapulgite clay on cadmium stress to A. membranaceus roots were more obvious with the increase of cadmium stress time. The above results showed that the addition of attapulgite clay into the growth substrate has certain alleviative effect on the cadmium stress to A. membranaceus seedlings.

Recent Progress of Imprinted Polymer Photonic Waveguide Devices and Applications.

Polymers are promising materials for fabricating photonic integrated waveguide devices. Versatile functional devices can be manufactured using a simple process, with low cost and potential mass-manufacturing. This paper reviews the recent progress of polymer photonic integrated devices fabricated using the UV imprinting technique. The passive polymer waveguide devices for wavelength filtering, power splitting, and light collecting, and the active polymer waveguide devices based on the thermal-optic tuning effect, are introduced. Then, the electro-optic (EO) modulators, by virtue of the high EO coefficient of polymers, are described. Finally, the photonic biosensors, which are based on low-cost and biocompatible polymer platforms, are presented.

A new cycloartane nortriterpenoid from stem and leaf of Quercus variabilis.

A new compound 3-acetyloxy-epicycloeucalenol-24-one (1), with 11 known compounds 3α-acetyloxy-4α,14α-dimethyl-9ß,19-cycloergost-24-oic acid (2), 3-epicycloeucalenol (3), 3-epicycloeucalenyl-24-one (4), 3-epicycloeucalenyl acetate (5), 4ß,14α-dimethyl-5α-ergosta-9ß,19-cyclo-24(31)-en-3ß-hydroxy-4α-carboxylic acid (6), cycloeucalenone (7), friedelin (8), epifriedelanol (9), lup-20 (29)-en-3ß,30-diol (10), betulin (11), lupeol (12), was isolated from the stems and leaves of Quercus variabilis Blume. Seven compounds (1-7) showed anti-inflammatory activity.

Correlation analysis of internal jugular vein abnormalities and cerebral venous sinus thrombosis.

BACKGROUND: Cerebral venous sinus thrombosis (CVST) is a special form of stroke with multiple causes and risk factors. However, there are still a portion of cases with unknown reasons. The aim of this study was to investigate the relationship between internal jugular vein (IJV) abnormalities and the development of CVST. METHODS: A total of 51 CVST patients and 30 healthy controls were enrolled. The diameter, the maximum velocity (Vmax) and the reflux time in bilateral IJVs were measured by color Doppler flow imaging (CDFI). The paired t test was used to compare the numeric values between the bilateral IJVs. The Pearson chi-square test was used to evaluate the relationship between IJV abnormality and CVST, IJV abnormality and IJV reflux, respectively. RESULTS: Among the 51 CVST patients, 20 (39%) patients were with normal IJV and 31 (61%) patients were with abnormal IJV. The types of IJV abnormality included annulus stenosis 19 cases (61%), hypoplasia 9 cases (29%), thrombosis 2 cases (7%) and anomalous valve 1 case (3%). In patients with unilateral IJV abnormality, the minimum diameter of the IJV on the lesion side was significantly smaller than that of the contralateral side (P < 0.0001). When compared with contralateral side, the Vmax of the lesion side with unilateral annulus stenosis was significant higher, however, it was obvious lower in patients with unilateral hypoplasia (P < 0.05). Furthermore, among 27 cases with unilateral IJV abnormality, all the CVST occurred on the same side as the IJV lesions. CONCLUSION: IJV abnormality closely correlated with the development of CVST, which is a newly identified risk factor for CVST.

Analysis of PCBs degradation abilities of biphenyl dioxygenase derived from Enterobacter sp. LY402 by molecular simulation.

Enterobacter sp. LY402 is a bacterium isolated from polluted soil. It can efficiently degrade polychlorinated biphenyls (PCBs) under aerobic conditions. However, the degradation was limited when it comes to high chlorine or double para-substituted PCBs. Biphenyl dioxygenase (BDO) is the key enzyme in the PCBs biodegradation process. It has been confirmed that the α-subunit of the iron-sulfur protein of biphenyl 2,3-dioxygenase (BphA1) directly influenced catalytic activities and substrate specificity. To know the degradation characteristics of BDO to PCBs, we analyzed PCBs degradation abilities of BphA1 from Enterobacter sp. LY402 by experiment and molecular simulation. Firstly, the degradation experiment of PCBs was performed, and the degradation rate constants (k) were calculated. Then the three-dimensional model of LY402-BphA1 was constructed. Through further docking studies with 209 PCB congeners, the PCBs binding abilities of LY402-BphA1 were measured and some crucial active site residues were identified. Moreover, the molecular descriptors of PCBs were calculated and analyzed to determine the correlation of molecular properties and degradation. The results showed that the affinity energy of PCBs was well matched with the k values of the different number of chlorine substituents. The binding ability of BphA1 greatly affected the PCBs degradation abilities of BDO. Hydrophobic contact was the main interaction between the residues of active site and PCB substrates. The number and subposition of chlorine substituents would influence the PCBs binding ability of BphA1 significantly. Ser283, Val287, Gly321 and Tyr384 residues in the active site of LY402-BphA1 showed high variability, and the space limitation of the active site of BphA1 had negative influence on the PCBs binding affinity of BDO. The changes of physical, electronic and geometrical properties could influence degradation and binding affinity of PCBs. Analysis of structural information, binding affinity and influences of molecular properties could be used to direct further modification of BDO to enhance biodegradation of PCBs and other toxic compounds.

Isolation and characterization of an Alcaligenes sp. strain DG-5 capable of degrading DDTs under aerobic conditions.

In this study, an Alcaligenes sp. strain DG-5 that can effectively degrade dichlorodiphenyltrichloro-ethanes (DDTs) under aerobic conditions was isolated from DDTs-contaminated sediment. Various factors that affect the biodegradation of DDTs by DG-5 were investigated. About 88 %, 65 % and 45 % of the total DDTs were consumed within 120 h when their initial concentrations were 0.5, 5 and 15 mg L⁻¹, respectively. However, almost no degradation was observed when their concentration was increased to 30 mg L⁻¹, but the addition of nutrients significantly improved the degradation, and 66 % and 90 % of the total DDTs were degraded at 336 h in the presence of 5 g L⁻¹ peptone and yeast extract, respectively. Moreover, the addition of 20 mM formate also enhanced the ability of DG-5 to transform DDTs, and its DDT transformation capacity (T(c)) value was increased by 1.8 - 2.7 fold for the pure (p,p'-DDT or o,p'-DDT only) and mixed systems (p,p'-DDT, o,p'-DDT, p,p'-DDD and p,p'-DDE). Furthermore, it was found that competitive inhibition in the biodegradation by DDT compounds occurred in the mixed system.

Congener selectivity during polychlorinated biphenyls degradation by Enterobacter sp. LY402.

The relationship between the selectivity of a particular polychlorinated biphenyls (PCBs) congener and its biodegradability under the same concentration, especially by Enterobacter sp. LY402, is less well studied. To measure congener selectivity of Enterobacter sp. LY402, several influencing factors were studied. The results showed LY402 effectively degraded coplanar 3,4,3',4'-chlorobiphenyl (CB) at a concentration of 0.05 µM, but not 0.5 µM. The degradation rates of 2,4,5,2',3'-CB and 2,4,5,2',4',5'-CB were increased significantly when the sample constituents were changed from 12 to 5 congeners or to one congener. This indicated that bioremediation of individual congener was affected by other congeners present in the mixture. Moreover, for PCBs containing one chlorine on each phenyl ring, the reactivity preference of LY402 was 2,2'-CB ≥ 3,3'-CB ≫ 4,4'-CB. For two ortho chlorines congeners of PCBs, 2,2'-CB was degraded faster than 2,6-CB. Although 2,6-CB and 4,4'-CB were poorly degraded, the addition of one (i.e., 2,4,4'-CB and 2,6,3'-CB) or two more chlorines (i.e., 2,4,2',4'-CB) on the phenyl ring significantly increased their biodegradability. In addition, comparing the two congeners of ortho-meta-chlorinated biphenyl, 2,3,2',3'-CB with neighbor meta chlorines was degraded slower than 2,5,2',5'-CB with interval meta chlorines. All these indicated that the transformation rates of PCBs were not consistent with the number of chlorines, and PCBs containing the same numbers of chlorines but at different positions also resulted in different conversions. In principle, the extents of effect caused by the position of chlorine substituents on the degradation of PCBs by LY402 were ortho- > meta- > para-CB. In conclusion, the congener selectivity of LY402 was determined by many factors, including the composition of the congeners, their concentrations in the mixture and location and number of chlorine substituents on the phenyl rings.

Color Doppler imaging evaluation of proximal vertebral artery stenosis.

OBJECTIVE: The sonographic diagnostic criteria for vertebral artery stenosis have not been fully investigated. The purpose of this study was to assess hemodynamic parameters at color Doppler imaging and to determine, with digital subtraction angiography as the reference standard, the optimal thresholds for evaluation of proximal vertebral artery stenosis. MATERIALS AND METHODS: Among 653 patients with symptoms of ischemia of the posterior circulation, 247 subjects with normal arteries or stenosis of the proximal vertebral artery confirmed with digital subtraction angiography were included in the study. Peak systolic velocity at the origin of the vertebral artery (PSV(origin)) and in intervertebral segments of the vertebral artery (PSV(IV)), end-diastolic velocity at the origin and in the intervertebral segments of the vertebral artery, and the diameter of the vascular lumen were measured. The cutoff values for the diagnosis of < 50%, 50-69%, and 70-99% stenosis were determined with receiver operating characteristics analysis. RESULTS: The optimal cutoff values of hemodynamic parameters in evaluation of stenosis of the proximal vertebral artery for < 50% stenosis were PSV(origin) >or= 85 cm/s, PSV(origin) / PSV(IV) >or= 1.3, and end-diastolic velocity at the origin >or= 27 cm/s; for 50-69% stenosis were PSV(origin) >or= 140 cm/s, PSV(origin) / PSV(IV) >or/= 2.1, and end-diastolic velocity at the origin >or= 35 cm/s; and for 70-99% stenosis were PSV(origin) >or= 210 cm/s, PSV(origin) / PSV(IV) >or= 4.0, and end-diastolic velocity at the origin >or= 50 cm/s. PSV(origin) was the most useful hemodynamic parameter, having accuracy of 94.5%, 96.2%, and 88.7% for the diagnosis of < 50%, 50-69%, and 70-99% stenosis. CONCLUSION: Color Doppler imaging is a reliable method for evaluation of vertebral artery stenosis. The results derived from this study can be used as a reference for establishing sonographic criteria for proximal vertebral artery stenosis.

Isolation and characterization of comprehensive polychlorinated biphenyl degrading bacterium, Enterobacter sp. LY402.

A Gram-negative bacterium, named LY402, was isolated from contaminated soil. 16S rDNA sequencing and measurement of the physiological and biochemical characteristics identified it as belonging to the genus Enterobacter. Degradation experiments showed that LY402 had the ability to aerobically transform 79 of the 91 major congeners of Aroclor 1242, 1254, and 1260. However, more interestingly, the strain readily degraded certain highly chlorinated and recalcitrant polychlorinated biphenyls (PCBs). Almost all the tri- and tetra-chlorobiphenyls (CBs), except for 3,4,3',4'-CB, were degraded in 3 days, whereas 73% of 3,4,3',4'-, 92% of the penta-, 76% of the hexa-, and 37% of the hepta-CBs were transformed after 6 days. In addition, among 12 octa-CBs, 2,2',3,3',5,5',6,6- CB was obviously degraded, and 2,2',3,3',4,5,6,6'- and 2,2',3,3',4,5,5',6'-CB were slightly transformed. In a metabolite analysis, mono- and di-chlorobenzoic acids (CBAs) were identified, and parts of them were also transformed by strain LY402. Analysis of PCB degradation indicated that strain LY402 could effectively degrade PCB congeners with chlorine substitutions in both ortho- and para-positions. Consequently, this is the first report of an Enterobacteria that can efficiently degrade both low and highly chlorinated PCBs under aerobic conditions.

[RP-HPLC determination of betulinic acid in Callicarpa macrophylla].

OBJECTIVE: To establish an RP-HPLC method for determination of betulinic acid in Callicarpa macrophylla, a commonly used herbal in Yunnan. METHOD: A Kromasil-C18 column (4.6 mm x 200 mm, 5 microm) and a mobile phase consisted of acetonitrile-0.1% phosphoric acid (63: 37) were used. The flow rate was 1.0 mL x min(-1) and the UV detector wavelength was 205 nm. RESULT: Betulinic acid was well separated from other compounds in C. macrophylla. The content of betulinic acid in C. macrophylla from different origins showed apparent differences, the content of betulinic acid in C. macrophylla from Yunnan was the highest. The calibration curve was linear in the range of 0.016 6-0.332 mg x mL(-1) of betulinic acid with correlation coefficient 0.999 8. The average recovery of betulinic acid was 98.5%. CONCLUSION: The method is simple, accurate and reproducible, and is suitable for the quality control of C. macrophylla.