首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 31 毫秒
1.
The structure of the carbohydrate moiety of GP–I–a, one of three glycopeptides obtained from Rhizopus saccharogenic amylase, was determined by using enzymatic and chemical techniques.

Six residues (all of the residues in GP–I–a) of mannose and one residue of N-acetylglucosamine were released in that order when GP–I–a was digested successively with purified α-mannosidase and β-N-acetylglucosaminidase.

Exhaustive methylation of GP–I–a gave 3,6-di-O-methyl derivative from the N-acetylglucosamine residues, and 2,3,4,6-tetra-O-methyl, 3,4,6-tri-O-methyI and 2,4-di-O-methyl derivatives from the mannose residues in an approximate ratio of 3: 1:2.

After one step of the Smith degradation of GP–I–a, a residual glycopeptide (F–1) consisted of one mole each of asparagine and glycine and two moles each of mannose and N-acetylglucosamine was obtained. Exhaustive methylation of F–1 gave 3,6-di-O-methyl derivative of N-acetylglucosamine, and 2,3,4,6-tetra-O-methyl and 2,3,4-tri-O-methyl derivatives of mannose in a ratio of 1.00: 0.91.

Partial acetolysis of 1→6 linkages in GP–I–a yielded mannose, 3-O-mannosylmannose and a smaller glycopeptide which was resistant to the acetolysis.

From these and other evidences, the following structure was determined for GP–I–a.  相似文献   

2.
The hagfishes of the genus Eptatretus (Myxinidae) from southern Africa are known from three poorly studied species: Eptatretus hexatrema, a common species from Namibia and South Africa; Eptatretus profundus, known only from the holotype collected off Cape Point (South Africa); and Eptatretus octatrema, known from two syntypes from the Agulhas Bank (South Africa). Taxonomic, morphological and distributional information about these three species are reviewed and updated based on the examination of additional specimens collected in South African waters. Eptatretus hexatrema differs from all congeners by having six pairs (rarely seven) of gill apertures arranged in a straight line, 3/2 multicusp pattern of teeth, total cusps 44–49, trunk pores 53–60, total pores 93–107, preventral length 45.1–57.4% TL, tail length 11.6–14.3% TL, tail depth 5.7–8.1% TL, and two bilaterally symmetrical nasal-sinus papillae. Eptatretus octatrema differs from all congeners by having usually eight (some specimens with seven) pairs of gill apertures arranged in a straight line, 3/2 multicusp pattern of teeth, 42–46 total cusps, 22–26 prebranchial pores, 63–68 trunk pores, 104–117 total pores, and two bilaterally symmetrical nasal-sinus papillae. Eptatretus profundus differs from all congeners by having five pairs of gill apertures arranged in a straight line, 3/2 multicusp pattern of teeth, total cusps 42–46, prebranchial pores 12–15, branchial pores 4–5, trunk pores 48–52, tail pores 15–17, total pores 81–86, and body depth at PCD 7.0–9.7% TL. An identification key for the hagfishes from southern Africa is provided and the conservation status of E. octatrema, a species considered to be Critically Endangered, is discussed in light of the new findings.  相似文献   

3.
Further selection for a better strain capable of producing D(?)-α-aminobenzylpenicillin (APc) from 6-aminopenicillanic acid (6–APA) was carried out. Pseudomonas melanogenum KY 3987 was consequently selected as a new strain possessing an APc-specific penicillin acylase.

The acylase could synthesize APc in good yields from 6–APA and phenylglycine ester and form 6–APA only from APc, not from other common penicillins. Since the Pseudomonas acylase was found incapable of forming penicillin G (Pc–G) from 6–APA and phenylacetic acid, in contrast with E. coli and Kluyvera citrophila enzymes, the enzymatic hydrolysate of Pc–G, for example by K. citrophila cells, which contained 6–APA and phenylacetate, became employed as a source of 6–APA instead of purified 6–APA to synthesize APc by the cells of P. melanogenum.  相似文献   

4.
A laboratory experiment was conducted to determine the effect of the pupal age of Calliphora erythrocephala (Meigen) on the reproductive biology (in terms of number, size, developmental time and longevity of progeny) of the parasitoid Melittobia acasta Walker. Melittobia acasta females of uniform size were given five C. erythrocephala pupae from one of four experimental age groups: 17–24 h, 24–48 h, 48–72 h and 72–96 h, for parasitization. The mean number of progeny produced from the experimental age groups for a 24 h period were 2, 7.6, 15.6 and 13.6, respectively. The parasitoids preferred hosts that were 48–72 h old. There were no significant differences in the mean development time (18.2 days) and size of progeny (mean head width = 0.38 ± 0.01 mm) produced from the experimental host age groups. The longevity of progeny from the four host age groups varied (range: 4–39 days), with those from the 48–72 h group living longest (mean = 25 days). The F1 females from the 48–72 h group were reproductively more successful than those from the other groups, producing a mean F2 progeny of 912 individuals when compared with 867, 801 and 757 individuals from the 24–48 h, 72–96 h and 17–24 h age groups, respectively. These findings make significant contributions to our knowledge of the breeding and utilization of this parasitoid for the biological control of dipteran flies in pigsties and poultry houses.  相似文献   

5.
This paper revises and updates taxonomic and distributional information about hagfishes (Myxinidae) from Australia. It covers five species of the genus Eptatretus: Eptatretus cirrhatus known from eastern Australia and also distributed around New Zealand, Eptatretus longipinnis endemic to South Australia, Eptatretus strahani originally described from the Philippines and reported here as a new record from Western Australia and two new species described herein as Eptatretus alastairi and Eptatretus gomoni, both from Western Australia. Eptatretus alastairi is distinguished from all congeners by the unique combination of the following characters: six pairs of gill pouches; three‐cusp multicusps on the anterior and posterior rows of cusps; anterior unicusps 9–12; posterior unicusps 8–11; total cusps 48–56; prebranchial pores 13–16; branchial pores 5–6; trunk pores 50–55; tail pores 11–13; total pores 83–88; two bilaterally symmetrical nasal‐sinus papillae in the dorsal surface of the nasal sinus. Eptatretus gomoni is distinguished from all congeners by the unique combination of the following characters: eight pairs of gill pouches; three‐cusp multicusps on the anterior and two‐cusp multicusps on the posterior row of cusps; anterior unicusps 10–11; posterior unicusps 9–10; total cusps 50; prebranchial pores 12–13; branchial pores 7–8; trunk pores 57–58; tail pores 14–15; total pores 91–93; no nasal‐sinus papillae. An identification key for the Australian species of Eptatretus is also provided.  相似文献   

6.
Okinawa, the only subtropical area in Japan with numerous island ecosystems, is expected to have diverse microbial resources. Recently, we reported the construction of a culture filtrate library with microbes originally isolated from soils in Okinawa, including the Yaeyama Archipelago, and validated its phylogenetic diversity. In the present study, we investigated the inhibitory effect of the cell extract (CE) from microbial isolate 3–45 against Magnaporthe oryzae in rice (Oryza sativa). Abnormal appressorium formation by M. oryzae was induced in the presence of the CE from isolate 3–45. Additionally, melanization of appressoria was inhibited in the presence of CE from isolate 3–45. Sequence analysis of the 16S rDNA region of isolate 3–45 indicated that it shared similarities with Streptomyces erythrochromogenes. When rice leaves were inoculated with M. oryzae in the presence of CE from isolate 3–45, blast lesion formation was inhibited compared to leaves treated with M. oryzae in the absence of CE from isolate 3–45. In addition, M. oryzae infective activity was significantly inhibited in rice leaf sheaths treated with CE from isolate 3–45. Furthermore, abnormal appressorium formation was observed in the presence of heat‐treated CE from isolate 3–45. These results suggest that CE from isolate 3–45 can protect rice from blast disease caused by M. oryzae. Further studies are required to identify the active compounds present in 3–45‐CE and to clarify its mechanism of inhibition in full detail. The present study on isolate 3–45 might contribute to the development of a new fungicide for controlling rice blast disease caused by M. oryzae.  相似文献   

7.
Citrus canker [caused by Xanthomonas citri subsp. citri (Xcc)] can cause yield loss of susceptible citrus and result in trade restrictions of fresh fruit. For both regulatory purposes and epidemiological studies, accurate detection and quantification of viable inoculum are critical. Two accepted methods used to detect and quantify Xcc are injection–infiltration bioassay and culture, but these two methods have not been directly compared using field‐obtained samples. The two methods were compared using washates of lesions taken from fruit, leaves and shoots in a commercial orchard in Florida in 2009–2010 and 2010–2011, with bioassay being the assumed standard. Despite some misclassifications, true positives (sensitivity) and true negatives (specificity) were the dominant classes using culture. False positives for lesions from shoots ranged from 13.1 to 21.4% in 2009–2010 and 2010–2011, respectively, and false positives for lesions from fruit and leaves ranged from 4.3 to 15.7%, in the two seasons, respectively. The false positive rate for culture compared with injection–infiltration bioassay was highest (0.16–0.55), due to more frequent recovery of Xcc by culture at ≤103 colony‐forming units (CFU) Xcc per ml. The false negative rate was consistently lower (0.02–0.21), confirming that in only a few cases did culture fail to detect Xcc when it was present. The area under the curve for receiver operator characteristic analysis ranged from 0.80 to 0.97, confirming that culture provided an accurate diagnosis in most cases. There was a higher frequency of lesions from shoots with a CFU ≤103 Xcc compared with lesions from fruit or leaves, making culture more effective at detecting these. The data demonstrate that culture is a reliable way to detect and quantify Xcc compared with injection–infiltration bioassay, particularly when the CFU is ≤103 Xcc per ml.  相似文献   

8.
Hemiodus bimaculatus sp. nov., is described from tributaries of the Rio Juruena and Rio Teles Pires in the upper Rio Tapajós basin. The new species is diagnosed from most congeners, except Hemiodus jatuarana, by having a conspicuous circular or horizontally elongate dark blotch on the caudal peduncle (v. inconspicuous in H. iratapuru and absent in the other species). The new species differs from H. jatuarana by having a round midlateral spot on the flank (v. absent in H. jatuarana), 98–121 perforated scales in the lateral line (v. 66–72 in H. jatuarana), 23–28 scale series above and 14–19 below lateral line (v. 12–13 above and 6–7 below in H. jatuarana). Hemiodus bimaculatus is hypothesised to be related to species of the H. microlepis group, from which it also differs by having 11–25 epibranchial (v. 26–34 in H. argenteus, 29–39 in H. microlepis, 21–42 in H. orthonops and 27–35 in H. parnaguae) and 18–31 ceratobranchial (v. 38–50 in H. argenteus, 43–58 in H. microlepis, 32–52 in H. orthonops and 34–48 in H. parnaguae) gill rakers in the first arch.  相似文献   

9.
The structure of the carbohydrate moiety of GP–I–b which is one out of three glycopeptides isolated from a Pronase digest of the saccharogenic amylase of Rhizopus javanicus sp. 3–46, was investigated by enzymatic and chemical techniques.

Nine moles of mannose followed by one mole of N-acetylglucosamine were released per mole of GP–I–b when it was treated sequentially with purified jack bean α-mannosidase and β-N-acetylglucosaminidase.

Methylation of GP–I–b gave 3, 6-di-O-methyl derivative from the N-acetylglucosamine residues, and 2, 3, 4, 6-tetra-O-methyl, 3, 4, 6-tri-O-methyl and 2, 4-di-O-methyl derivatives from the mannose residues in an approximate ratio of 3: 4: 2.

A smaller glycopeptide (F–l) containing two moles each of mannose and N-acetylglucosamine per mole of asparagine was obtained when GP–I–b was subjected to one step of the Smith degradation. Exhaustive methylation of F–l gave 3, 6-di-O-methyl derivative of Nacetylglucosamine, and 2, 3, 4, 6-tetra-O-methyl and 2, 3, 4-tri-O-methyl derivatives of mannose in a ratio of 1.00: 0.85.

Controlled acetolysis of GP–I–b yielded mannose, O-α-mannosyl-(l→2)-O-α-mannosyl-(l→3)-mannose and a smaller glycopeptide which was resistant to the acetolysis.

From these and previous evidences, the following structure was determined for GP–I–b.  相似文献   

10.
The subtidal brown algal species Sporochnus dotyi Brostoff (Sporochnales, Phaeophyceae), which has been regarded as a Hawaiian endemic, is reported from Kushimoto, Kii Peninsula, Pacific coast of central Honshu, Japan, for the first time outside Hawai'i. The species grew on subtidal rocks ca. 5–20 m deep attached by a small conical holdfast. The erect thalli were 5–30 cm high, terete, robust and alternately branched in 1–2 orders. When mature, pedicellate receptacles developed on the branches, and formed elliptical sori 1 mm long with a pedicel 3–5 mm long. The apical parts of the thalli and the receptacles were terminated with a tuft of simple assimilatory filaments of up to 4 mm long and showed prominent green to yellow underwater iridescence. Reproductive filaments (paraphyses) were densely packed, simple, up to 200 μm long and bore 4–6 mostly unilateral unilocular zoidangia 20–22 μm long and 5–6 m in diameter. In the genetic analyses, the Sporochnus alga from Kushimoto had partial rbcL sequence identical to S. dotyi from Hawai'i. The cox3 phylogeny revealed that this alga formed a fully supported clade with S. dotyi. Therefore, we identified the alga from Kushimoto as S. dotyi. This finding of S. dotyi from Japan, together with the recent reports of the mesophotic macroalgae Ryuguphycus kuaweuweu (=Umbraulva kuaweuweu), Ulva iliohaha and Newhousia imbricata from various localities in the Pacific Ocean including Japan, suggest closer biogeographical connections of subtidal/mesophotic macroalgae in the Pacific than previously recognized.  相似文献   

11.
The conditions for biotin production were investigated. Urea was a more effective nitrogen source than ammonium chloride and ammonium sulfate. About 60% conversion from dl-cis-tetrahydro-2-oxo-4-n-pentyl-thieno-(3,4-d)-imidazoline (dl-TOPTI) to biotinol and biotin occurred using Corynebacterium sp. B–321. Strain M–6318 which derived from B–321 as a mutant incapable of assimilating n-alkane produced large amounts of dl-biotin from dl-TOPTI. The inability of the microbe to assimilate n-alkane resulted in repression of biotin degradation. Maximum conversion (80%) was obtained by growing cultures of strain M–6318 in the constant presence of n-paraffin.  相似文献   

12.
13.
The aim of current work was to determine essential oils (EOs) composition from three Eucalyptus species, including E. citriodora, E. camaldulensis and E. globulus and assess their α-glucosidase inhibitory activity. The EOs were collected using the hydrodistillation technique and characterized by GC/MS, GC-FID and NMR. The isolated EOs from leaves parts of Eucalyptus species varied from 0.56 to 1.0 % on fresh weight basis. The content of the EOs was distinct according to the species. The most abundant metabolites were identified as citronellal (0–83.0 %), 1,8-cineole (0.2–44.8 %), spathulenol (0.4–16.1 %) α-pinene (0.4–15.9 %), p-cymene (3.7–11.9 %), citronellol (0–8.6 %), β-eudesmol (5.3–8.6 %) and β-pinene (0–7.1 %). The EOs obtained from targeted samples exhibited strong α-glucosidase inhibitory activity. These results are encouraging and underline that the EOs of Eucalyptus species may be a promising alternative source of natural antidiabetic.  相似文献   

14.
The morphology, infraciliature, and silverline system of three peritrichous ciliates, Zoothamnium bucciniiformum sp. n., Zoothamnium florens sp. n., and Zoothamnium zhanjiangense sp. n., were investigated based on both living and silver‐stained specimens. Zoothamnium bucciniiformum sp. n., collected from coastal waters (salinity 30‰) off Zhanjiang, southern China, can be distinguished by the following characters: dichotomously branched stalk, peristomial lip with medial circumferential infolding, contractile vacuole apically positioned, 32–49 silverlines between the anterior end and the aboral trochal band, 15–26 between the aboral trochal band and the scopula; two kineties in peniculus 3, not parallel to each other. Zoothamnium florens sp. n., collected from a mangrove wetland (salinity 13‰) off Zhanjiang, is characterized by its large conical zooid, tuberculate peristomial lip, asymmetrical dichotomously branched colony, 59–81 silverlines between the anterior end and the aboral trochal band and 29–36 between the aboral trochal band and the scopula. Zoothamnium zhanjiangense, collected from a mangrove wetland (salinity about 9.5‰) off Zhanjiang, differs from its congeners by the alternately branched stalk, peristomial lip with medial circumferential infolding, 40–63 silverlines from the peristomial area to the aboral trochal band and 13–24 from the aboral trochal band to the scopula. The comparison and analysis of SSU rDNA sequences also support present identifications.  相似文献   

15.
ABSTRACT. The following species are described from Indonesian birds: Isospora paddae n. sp. with oocysts 41.5–45.5 × 40.3–41.5 (44 ± 1.15 × 41.2 ± 0.38) and sporocysts 22.8–24.5 × 14.7–17 (24 ± 0.55 × 16.2 ± 0.81) from the Java sparrow, Padda oryzivora, and Isospora indonesianensis n. sp. with oocysts 39.3–43.6 × 37–40.8 (41.8 ± 1.3 × 39.6 ± 1.25) and sporocysts 25.6–28.4 × 15.2–18.5 (27.1 ± 1.05 × 16.8 ± 1.22) from the chestnut Munia, Lonchura malacca (L.). The host birds belong to the order Passerorida.  相似文献   

16.
A comparative study of the sugar composition of O-antigenic lipopolysaccharides (LPS) isolated from Vibrio alginolyticus and those from V. parahaemolyticus was carried out. 3-Deoxy-d-mannooctulosonic acid, 2-keto-3-deoxy octonate (KDO), a regular sugar constituent of gram-negative bacterial LPS, was totally absent from LPS of all V. alginolyticus strains examined as it was from those of V. parahaemolyticus. Furthermore, a KDO-like thiobarbituric acid test-positive substance, identical with that of either V. parahaemolyticus 07 or 012, was also found in LPS from three strains, 505–78, 905–78, and 1013–79 (designated tentatively as group I), out of the five strains of V. alginolyticus tested. LPS from the members of group I contained, as component sugars, glucose, galactose, l-glycero-d-manno-heptose, glucosamine, galactosamine, the KDO-like substance, and an unidentified amino sugar P1. Thus, LPS of the members of group I possessed a similar sugar composition which is similar to that of LPS from either V. parahaemolyticus 07 or 012. LPS of strain 1027–79, one of the other two strains (designated tentatively as gorup II), contained as component sugars, glucose, l-glycero-d-mannoheptose, glucosamine, galactosamine, and the other unidentified amino sugar P2, while LPS of strain 53–79, the other member of group II, contained galactose as an additional component. The results indicate that LPS of strain 1027–79 has a sugar composition similar to that of V. parahaemolyticus 09 LPS.  相似文献   

17.
OprJ, overproduced in nfxB multidrug-resistant strains of Pseudomonas aeruginosa, and OprK, overproduced in the multidrug-resistant strain K385, were demonstrated to be immunologically cross-reactive using an OprJ-specific monoclonal antibody. Treatment of the purified proteins with trypsin or chymotrypsin yielded virtually indistinguishable digestion patterns, and the N-terminal sequence of two trypsin fragments was identical for both proteins, indicating that OprJ and OprK share identity. The N-terminal amino acid sequences were used to facilitate cloning of the oprJ gene on a 5kbp KpnI fragment and a 10kbp BamHI fragment. Nucleotide sequencing of portions of these fragments revealed that oprJ was the terminal gene in a putative three-gene operon, The predicted mexC–mexD–oprJ gene products exhibit homology to the MexA–MexB–OprM components of the multidrug-resistance efflux pump of P. aeruginosa (43–46% identity). Consistent with an implied role for mexC–mexD–oprJ in drug efflux, the mexC–mexD–oprJ-hyperexpressing strain K385 showed reduced accumulation of a variety of antibiotics as compared with its parent strain, and this drug ‘exclusion’ was abrogated by energy inhibitors. The mexC and oprJ products are putative lipoproteins of a molecular mass of 40707 and 51742Da, respectively, while mexD was predicted to encode a protein of 111936Da. Sequencing upstream of mexC revealed the presence of the nfxB gene transcribed divergently from the efflux genes. Overproduction of OprJ and the attendant multiple-antibiotic resistance of strain K385 was shown to result from a point mutation in nfxB, resulting in a H87→R change in the predicted NfxB polypeptide. OprJ overproduction and multidrug resistance in K385 was reversed by the cloned nfxB gene, suggesting that nfxB encodes a repressor of mexC–mexD–oprJ expression. Consistent with this, the cloned nfxB gene repressed synthesis of a mexClacZ fusion in Escherichia coli. nfxB also repressed expression of a nfxBlacZ fusion, indicating that NfxB negatively regulates its own expression. These data indicate that the multidrug resistance of nfxB strains is due to overexpression of an efflux operon, mexC–mexD–oprJ, encoding components of a second efflux pump in P. aeruginosa.  相似文献   

18.
Hydrodistilled essential oils (EO) of Psidium guajava L. leaves from different regions in China were analyzed by GC and GC/MS. The samples from Guangdong Province displayed high EO yields (0.61 – 0.75%, v/w). A total of 50 components, representing over 98.00% of the EOs, were identified and semi‐quantitatived. The major constituents of EOs included β‐caryophyllene (17.17 – 31.38%), γ‐gurjunene (9.17 – 15.22%), τ‐cadinol (1.35 – 10.02%) and calamenene (2.13 – 7.80%). The terpenoids in all sample oils were dominated by sesquiterpenes hydrocarbons (70.18 – 84.35%), followed by oxygenated sesquiterpenes (9.89 – 22.19%). The similarities and differences among EOs from different samples were evaluated by hierarchical cluster analysis and principal component analysis methods. The IC50 values of EOs from different regions were between 18.52 – 33.72 mg/ml (DPPH) and 13.12 – 25.15 mg/ml (ABTS+). The FRAP value of EO from Guangdong Province was 7.34 – 9.13 mmol Vc/g DM, while the FRAP value of EO from Taiwan Province was 2.29 – 2.36 mmol Vc/g DM. The antimicrobial tests revealed that EO had a higher antimicrobial activity against all Gram‐positive bacteria and two fungi. Moreover, EO from Pguajava leaves of Guangdong Province showed the highest antimicrobial activity. These properties can be considered in the design of industrial products and for further application in the food, pharmaceutical and cosmetic industries.  相似文献   

19.
A series of natural crystal proteins from B. thuringiensis subsp. Alesti 12–25, caucasicus, galleriae 11–67, galleriae 6–96, kenyae, and shondungensis and spore‐crystal preparations from finitimus 11–66 and from a recombinant strain of B. thuringiensis subsp. kurstaki expressing Cry 1 Ga1 only, were assessed as a toxic agent for the pine processionary caterpillar, Thaumetopoea pityocampa. Some preparations had a thoroughly investigated composition and contained Cry1Aa, Cry1Ab2, Cry1Ab7, Cry1D, Cry1F, Cry 1 Ga1, Cry9Aa, Cry26 crystal proteins, whereas crystals of B. thuringiensis subsp. caucasicus, kenyae, and shondungensis harboured predominantly unidentified toxins distant from commonly used prototypes. Bioassays were based on the simultaneous assignment of each treatment to groups of 20 full sibling first‐instar larvae, obtained from broods of a population from North‐western Italy. The toxin was applied to pine needles by the leaf dipping method and the effect was registered in both feeding inhibition and mortality. B. thuringiensis subsp. caucasicus, kenyae, galleriae 6–96, alesti, and galleriae 11–67 gave the best results in terms of both feeding inhibition and larval mortality. Broods tested in B. thuringiensis bioassays showed a substantial variation in susceptibility to the toxins, suggesting the potential development of resistance in the population.  相似文献   

20.
Stipa narynica M. Nobis sp. nov. from the western Tian‐Shan Mts (western Kyrgyzstan) is described and illustrated. The new species belongs to sect. Smirnovia Tzvel. Morphologically the species is similar to S. aktauensis, a species from which it is easily distinguished by its longer glumes (41–)44–55(–62) mm vs 35–45 mm, longer anthecium (11.5–) 12.0–14.2(–14.8) mm vs 9.5–11.2(–11.7) mm, longer hairs on the seta (5.5–)6.0–8.0(–8.5) mm vs (3.0–)3.8–5.5(–6.0) mm and by the top of the lemma which in S. narynica is either glabrous or with a poorly developed ring of short hairs, while in S. aktauensis, the top of lemma is always distinctly and densely pilose. The lemma and leaf blade structure of both species were examined by means of SEM. The main features differentiating S. narynica and S. aktauensis and distribution of the taxa are presented. An original key to the middle Asiatic species of the sect. Smirnovia, the most similar to Stipa narynica is provided.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号