A new species of Papaveraceae, Corydalis sunhangii, in the section Trachycarpae, is described and illustrated from Nyingchi City, Xizang, China. The new species has some resemblance to Corydalis kingdonis, but differs by radical leaves prominent, usually several, blade tripinnate (vs. insignificant, few, blade bi- to triternate); cauline leaf usually one, much smaller than radical leaves, usually situated in lower half of stem (vs. usually two, larger than radical leaves, concentrated in upper third of stem); racemes densely 13-35-flowered (vs. rather lax, 4-11-flowered); claw of lower petal shallowly saccate (vs. very prominently and deeply saccate); capsule oblong, with raised lines of dense papillae (vs. broadly obovoid, smooth). Phylogenetic analysis, based on 68 protein-coding plastid genes of 49 samples, shows that C. sunhangii is not closely related to any hitherto described species, which is consistent with our morphological analysis.
BACKGROUND: Accurate species delimitation is fundamental for testing evolutionary theory and provides essential implications for conservation management. The arctic-alpine genus Saxifraga L. (Saxifragaceae) is taxonomically complex and many species have not been critically assessed. The taxonomic and phylogenetic status of Saxifraga lancangensis Y.Y.Qian, considered as a synonym of Saxifraga mengtzeana Engl. & Irmsch. in previous studies, is re-evaluated in light of new evidence presented here. RESULTS: Evidence from morphological comparison and sequencing of plastid genome indicate that S. lancangensis belongs to Saxifraga sect. Irregulares Haw., and is closely related to Saxifraga geifolia Balf.f., and S. mengtzeana. However, S. lancangensis can be diagnosed by its petals with red and clawless base, leaf blade orbicular and leaf margin shallowly dentate. CONCLUSIONS: The morphological and molecular evidence support the resurrection of S. lancangensis as a distinct species. An updated morphological description based on protologue and fresh material, diagnostic characters, and original photographs of the resurrected species are presented.
The purpose of this study was to study the relationship between maternal ABO blood groups and pregnancy outcomes. A total of 29,658 couples in Dongguan were selected as the research subjects. We obtained data on ABO blood groups and pregnancy outcomes and explored the relationship between them through log binomial regression and survival analysis. Compared to mothers with type B blood, the RR of foetal stillbirth in mothers with type A blood was 2.87 (95% CI: 1.70, 4.85), and compared to mothers with type O blood, the RR was 1.72 (95% CI: 1.16, 2.55). Compared with foetuses of other three blood type mothers, foetuses of A blood type mothers have a higher median birth weight (P = 0.011). Other pregnancy outcomes, including preterm birth, macrosomia, caesarean section, multiple births, birth defects, low birth weight, foetal sex, gestational days, birth length, and APGAR score, were not significantly different. The relationship between maternal ABO blood type and pregnancy outcomes was not affected by paternal blood type. More studies are needed to confirm these results.
What is already known on this subject? The relationship between blood type and disease is being increasingly studied. With regard to the relationship between maternal blood type and pregnancy outcomes, some studies have focused on people undergoing in vitro fertilisation. There are few reports on healthy women.What do the results of this study add? Compared to mothers with type B blood, the RR of foetal stillbirth in mothers with type A blood was 2.87 (95% CI: 1.70, 4.85), and compared to mothers with type O blood, the RR was 1.72 (95% CI: 1.16, 2.55). Compared with foetuses of other three blood type mothers, foetuses of A blood type mothers have a higher median birth weight (P = 0.011).What are the implications of these findings for clinical practice and/or further research? This study is the first to explore the relationship between blood type and pregnancy outcomes in healthy women.These results can provide some clues for the study of the mechanism of pregnancy outcomes.
ABO Blood-Group System , Premature Birth , Pregnancy , Infant, Newborn , Humans , Female , Retrospective Studies , Cesarean Section , Sex Factors , Pregnancy Outcome , Birth Weight
The genus Corydalis, with ca. 530 species, has long been considered taxonomically challenging because of its great variability. Previous molecular analyses, based on a few molecular markers and incomplete taxonomic sampling, were clearly inadequate to delimit sections and subgenera. We have performed phylogenetic analyses of Corydalis and related taxa, using 65 shared protein-coding plastid genes from 313 accessions (including 280 samples of ca. 226 species of Corydalis) and 152 universal low-copy nuclear genes from 296 accessions (including 271 samples of Corydalis) covering all 42 previously recognized sections and five independent "series". Phylogenetic trees were inferred using Bayesian Inference and Maximum Likelihood. Eight selected morphological characters were estimated using ancestral state reconstructions. Results include: (i) of the three subgenera of Corydalis, two are fully supported by both the plastid and nuclear data; the third, subg. Cremnocapnos, is weakly supported by plastid DNA only, whereas in the nuclear data the two included sections form successive outgroups to the rest of the genus; (ii) among all 42 sections and five "series", 25 sections and one "series" are resolved as monophyletic in both data sets; (iii) the common ancestor of Corydalis is likely to be a perennial plant with a taproot, yellow flowers with a short saccate spur, linear fruits with recurved fruiting pedicels, and seeds with elaiosomes; (iv) we provide a new classification of Corydalis with four subgenera (of which subg. Bipapillatae is here newly described), 39 sections, 16 of which are consistent with the previous classification, 16 sections have been recircumscribed, one section has been reinstated and six new sections are established. Characters associated with lifespan, underground structures, floral spur, fruit and elaiosomes are important for the recognition of subgenera and sections. These new phylogenetic analyses combined with ancestral character reconstructions uncovered previously unrecognized relationships, and greatly improved our understanding of the evolution of the genus.
Corydalis , Papaveraceae , Phylogeny , Corydalis/genetics , Bayes Theorem , Flowers/genetics
OBJECTIVES: To explore the relationship between a history of induced abortion and follow-up preterm birth. METHODS: We performed a retrospective cohort study of 27,176 women aged 19 to 48 years old in the city of Dongguan. Participants were divided into two groups according to the history of induced abortion. We used log-binomial regression to estimate adjusted risk ratios of preterm birth (gestation at less than 37 weeks) and early preterm birth (gestation at less than 34 weeks) for women with a history of induced abortion. Four models adjusted for different baseline data were used to verify the stability of the results. We also performed a subgroup analysis and mediation effect analysis to control for the influence of confounding factors and analyzed the relationship between the number of abortions and subsequent preterm birth. RESULTS: Our study included 2,985 women who had undergone a prior induced abortion. Women who reported having a prior induced abortion were more likely to have preterm births before 37 weeks and 34 weeks, with risk ratios of 1.18 (95% CI 1.02-1.36) and 1.65 (95% CI 1.23-2.21), respectively. The above associations were stable in all models. We also found that a history of induced abortion was independently associated with a higher risk of preterm birth and early preterm birth in the subgroups. After controlling for the indirect effect of demographic data, the direct effect of abortion history on follow-up preterm delivery was still significantly different. The higher the number of abortions, the greater the risk of subsequent preterm birth. CONCLUSIONS: This study suggests that induced abortion increases the risk of subsequent preterm birth.
Abortion, Induced , Abortion, Spontaneous , Premature Birth , Pregnancy , Infant, Newborn , Female , Humans , Young Adult , Adult , Middle Aged , Premature Birth/epidemiology , Premature Birth/etiology , Retrospective Studies , Abortion, Induced/adverse effects , Abortion, Spontaneous/epidemiology , Abortion, Spontaneous/etiology , Odds Ratio
In the Flora of China account of Saxifraga mengtzeana Engl. & Irmsch., eight synonyms were attributed to it and one variant, recognized as Saxifraga epiphylla Gornall & Ohba, was split from it. This study reevaluates the taxonomic status of some of the synonyms and of the segregated species in light of new evidence presented here. Morphological and molecular evidence demonstrate that collections from northwestern Yunnan and Sichuan are genetically differentiated from those in southeastern Yunnan and neighboring Guangxi. Observations in the field and in cultivation show that the peltate petiole attachment diagnostic of S. mengtzeana var. peltifolia Engl. & Irmsch. is developmentally labile. Similar observations combined with molecular data show that viviparous phenotypes, formerly treated as S. epiphylla, although largely under genetic control, occur sporadically throughout the ranges of both northern and southern taxa. Collections from northwestern Yunnan and Sichuan are best recognized as Saxifraga geifolia Balf.f., whereas those from southeastern Yunnan and neighboring Guangxi are S. mengtzeana. Peltate-leaved variants of the latter are given no status and are relegated to complete synonymy. Viviparous phenotypes of S. mengtzeana and S. geifolia are recognized at the rank of forma.
Corydalismicroflora and C.lidenii are recognised as separate species in "Flora of China" and the latest plant list. However, based on the examination of type specimens and field investigations, C.lidenii is shown to be conspecific with C.microflora. As a result, C.lidenii is synonymised with C.microflora in this study.
Trichoderma isolates were collected from moist soils near a water source in different areas of China. ITS sequences were submitted to MIST (Multiloci Identification System for Trichoderma) and meets the Trichoderma [ITS76] standard. Combined analyses of phylogenetic analyses of both phylograms (tef1-α and rpb2) and morphological characteristics, revealed five new species of Trichoderma, namely Trichodermahailarense, T.macrofasciculatum, T.nordicum, T.shangrilaense and T.vadicola. Phylogenetic analyses showed T.macrofasciculatum and T.shangrilaense belong to the Polysporum clade, T.hailarense, while T.nordicum and T.vadicola belong to the Viride clade. Each new taxon formed a distinct clade in phylogenetic analysis and have unique sequences of tef1-α and rpb2 that meet the Trichoderma new species standard. The conidiation of T.macrofasciculatum typically appeared in white pustules in concentric rings on PDA or MEA and its conidia had one or few distinctly verrucose. Conidiophores of T.shangrilaense are short and rarely branched, phialides usually curved and irregularly disposed. The aerial mycelium of T.hailarense and T.vadicola formed strands to floccose mat, conidiation tardy and scattered in tufts, conidiophores repeatedly rebranching in dendriform structure. The phialides of T.nordicum lageniform are curved on PDA and its conidia are globose to obovoidal and large.
OBJECTIVE: To explore whether a history of IUD use could increase the risk of subsequent preterm birth. METHODS: We performed a cohort study of 24,496 multipara aged 19-48 years in Dongguan City. Each subject was followed up for 1 year, and 12,508 women obtained pregnancy outcomes. They were divided into 2 groups: 2130 subjects with IUD use history (exposure group), and 10,378 subjects without IUD use history (control group). The exposure group will remove the IUD before pregnancy. The primary outcomes were preterm birth (less than 37 weeks of gestation) and early preterm birth (less than 34 weeks of gestation). We used log-binomial regression to estimate adjusted risk ratios (aRR) of preterm birth and early preterm birth for women with a history of IUD. According to the different adjusted baseline data, three regression models were established, and the propensity matching score method was also used to verify the stability of the results. RESULTS: The delivery rate of women with IUD history was 51.24%, and that of women without IUD was 51.03% (2 = 0.063, P = 0.802). Six hundred and eighty-five women had preterm birth (5.48%, 95% CI 5.08-5.88) and 133 women had early preterm birth (1.06%, 95% CI 0.83-1.24). Compared with the control group, the incidence of preterm birth and early preterm birth in the exposure group were significantly lower. The results are stable in all four models. Subgroup analysis also supported the result. This study also found that the longer the women used IUD before pregnancy, the younger the age of first using IUD, and the shorter the time from condom removal to pregnancy, the lower the incidence of premature birth. CONCLUSION: The women with a history of IUD use are less likely to have premature birth after the IUD is removed. More prospective studies are needed to confirm it.
Pregnancy Complications , Premature Birth , Adult , Cohort Studies , Female , Humans , Infant, Newborn , Middle Aged , Pregnancy , Pregnancy Outcome , Premature Birth/epidemiology , Premature Birth/etiology , Prospective Studies , Young Adult
Saxifragaviridiflora, a remarkable new species of the genus Saxifragasect.Irregulares (Saxifragaceae) from Guangxi, is described and illustrated herein. This new species morphologically differs from all known S.sect.Irregulares taxa by its greenish petals, verruculose sepals, and thick leathery leaf blade abaxially scarlet with white spots.
Smelowskia sunhangii, from Qinghai and Tibet (China), is described and illustrated. Morphological and molecular data indicate that S. sunhangii is closely related to Smelowskia tibetica, from which it is easily distinguished by the densely hirsute (vs. glabrous or sparsely pubescent), elliptic to ovate-lanceolate (vs. suborbicular, oblong, or lanceolate) fruits with undulate (vs. straight) margins. A re-evaluation of the widely distributed S. tibetica and related taxa is also provided.
To characterize the antigenic epitopes of the hemagglutinin (HA) protein of H1N1 influenza virus, a panel consisting of 84 clones of murine monoclonal antibodies (mAbs) were generated using the HA proteins from the 2009 pandemic H1N1 vaccine lysate and the seasonal influenza H1N1(A1) vaccines. Thirty-three (39%) of the 84 mAbs were found to be strain-specific, and 6 (7%) of the 84 mAbs were subtype-specific. Twenty (24%) of the 84 mAbs recognized the common HA epitopes shared by 2009 pandemic H1N1, seasonal A1 (H1N1), and A3 (H3N2) influenza viruses. Twenty-five of the 84 clones recognized the common HA epitopes shared by the 2009 pandemic H1N1, seasonal A1 (H1N1) and A3 (H3N2) human influenza viruses, and H5N1 and H9N2 avian influenza viruses. We found that of the 16 (19%) clones of the 84 mAbs panel that were cross-reactive with human respiratory pathogens, 15 were made using the HA of the seasonal A1 (H1N1) virus and 1 was made using the HA of the 2009 pandemic H1N1 influenza virus. Immunohistochemical analysis of the tissue microarray (TMA) showed that 4 of the 84 mAb clones cross-reacted with human tissue (brain and pancreas). Our results indicated that the influenza virus HA antigenic epitopes not only induce type-, subtype-, and strain-specific monoclonal antibodies against influenza A virus but also cross-reactive monoclonal antibodies against human tissues. Further investigations of these cross-reactive (heterophilic) epitopes may significantly improve our understanding of viral antigenic variation, epidemics, pathophysiologic mechanisms, and adverse effects of influenza vaccines.
Antibodies, Monoclonal/immunology , Hemagglutinin Glycoproteins, Influenza Virus/immunology , Immunodominant Epitopes/immunology , Influenza A Virus, H1N1 Subtype/immunology , Influenza, Human/immunology , Animals , Antibodies, Monoclonal/biosynthesis , Cells, Cultured , Cross Reactions , Epitope Mapping , Humans , Influenza A Virus, H3N2 Subtype/immunology , Influenza A Virus, H5N1 Subtype/immunology , Influenza A Virus, H9N2 Subtype/immunology , Influenza Vaccines/immunology , Mice , Tissue Array Analysis
Based on the continuous measurements of an open-path eddy covariance system, this paper analyzed the characteristics of energy balance components and evapotranspiration in a broad-leaved Korean pine forest in Changbai Mountains in 2008, as well as the differences of energy balance components and evapotranspiration between growth season and dormant season. For the test forest, the year-round energy balance closure was 72%, being at a medium level, compared to the other studies in the Fluxnet community. The energy balance components had significant differences in their diurnal and seasonal variations. In growth season, turbulent energy exchange was dominated by upward latent heat flux, accounting for 66% of available energy; while in dormant season, the turbulent energy exchange was dominated by upward sensible heat flux, accounting for 63% of available energy. The accumulated annual evapotranspiration in the study site in 2008 was 484.7 mm, occupying 87% of the precipitation at the same time period (558.9 mm), which demonstrated that evapotranspiration was the main water loss item in temperate forests of northern China.
Energy Metabolism , Pinus/metabolism , Plant Transpiration/physiology , Water/metabolism , China , Ecosystem
In the present study, the mechanism of antibacterial activity of cajanol extracted from the roots of Cajanus cajan (L.) Millsp. towards Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) was investigated. The antibacterial activity of cajanol was evaluated towards six bacterial strains (Staphylococcus epidermidis, Staphylococcus aureus, Bacillus subtilis, Escherichia coli, Proteus vulgaris, and Pseudomonas aeruginosa) by the broth microdilution method. It showed strong antibacterial activity towards all bacteria tested with minimal inhibition concentration (MIC) values ranging from 98.90 µM to 197.8 µM. Cajanol-induced death rates in the most sensitive strains ( E.COLI, 96.55 % and S. AUREUS, 97.25 %) were analyzed by flow cytometry. Furthermore, the activity of cajanol on the membranes of E. coli and S. aureus was investigated by using lecithin, phosphate groups, and fluorescence microscopy. Cajanol-induced DNA damage was observed by agarose gel electrophoresis. In summary, cajanol inhibited E. coli only by DNA damage, whereas S. aureus was inhibited by affecting both, the lecithin and phosphate groups on the cellular membrane and DNA. The present study shows that cajanol possesses antibacterial activity in vitro towards both gram-negative and gram-positive bacteria and therefore may be a promising candidate as an antibacterial agent for the therapy of microbial infections.
Anti-Bacterial Agents/pharmacology , Cajanus/chemistry , Escherichia coli/drug effects , Isoflavones/pharmacology , Staphylococcus aureus/drug effects , Cell Membrane/drug effects , DNA Damage/drug effects , Escherichia coli/growth & development , Gram-Negative Bacteria/drug effects , Gram-Negative Bacteria/growth & development , Gram-Positive Bacteria/drug effects , Gram-Positive Bacteria/growth & development , Microbial Sensitivity Tests , Plant Roots/chemistry , Staphylococcus aureus/growth & development
OBJECTIVE: To investigate the clinical value of global end-diastolic volume (GEDV) and intrathoracic blood volume (ITBV) in perioperative monitoring of the cardiac preload in patients undergoing orthotopic liver transplantations (OLT). METHODS: Eight ASA III or IV patients aged 42-50 years undergoing OLT without venovenous bypass under general anesthesia were enrolled in this study. Before the induction, a thermodilution femoral artery catheter was inserted into the femoral artery under local anesthesia and connected to a PiCCOplus system to monitor ITBV and GEDV. A CCO catheter was inserted into the right internal jugular vein to monitor the pulmonary artery obstruction pressure (PAOP), central venous press (CVP) and stroke volume (SVPAC). Anesthesia was induced with a combination of midazolam (0.1 mg/kg), propofol (1 mg/kg) and fentanyl (3 microg/kg). Pipecuronium (0.1 mg/kg) was given to facilitate naso-endotracheal intubation. Before anesthesia (T0) and at 10 min before the anhepatic phase (T1), 10 min after anhepatic phase (T2), 10 min after neohepatic phase (T3) and at the end of surgery (T4), all the TPTD and CCO parameters were measured by injecting 10 ml cold saline solution (below 8 degrees celsius;) via the distal port of the central venous catheter. RESULTS: ITBV and GEDV at T2 were significantly lower than those at T0, T1, T3 and T4 (P<0.05). SVPAC at T2 was dramatically decreased compared with that at T0 and T1 (P<0.05). The changes in the pressure preload parameters of the pulmonary artery catheter (PAOP and CVP) did not correlate to the changes in SVPAC, whereas the changes in the volume preload parameters (ITBV and GEDV) of the TPTD was significantly correlated to the changes in SVPAC (P<0.01). PAOP and CVP did not correlate to the changes in ITBV and GEDV. CONCLUSION: ITBV and GEDV are more reliable than PAOP and CVP in perioperative monitoring of the cardiac preload in patients undergoing OLT.
Liver Transplantation/methods , Monitoring, Intraoperative , Thermodilution , Adult , Blood Volume , Cardiac Output , Catheterization, Swan-Ganz , Central Venous Pressure , Female , Humans , Male , Middle Aged , Stroke Volume
OBJECTIVE: To investigate the effect of recombinant adenovirus-mediated hypoxia-inducible factor-1alpha (Ad-HIF-1alpha) at different doses on angiogenesis in a rabbit model of hind limb ischemia. METHODS: Left hind limb ischemia was induced in 45 Zealand white rabbits by ligation of the left femoral artery. The rabbits were randomly divided into 5 groups (n=9) to receive intramuscular injections of 0.5 ml saline, 2x10(10) PFU empty vector (Ad-null), or different doses of Ad-HIF-1alpha (2x10(9), 2x10(10) or 2x10(11) PFU) immediately after the operation. On the 7th day after the operation, real-time PCR was used to detect the expression of HIF-1alpha mRNA in the skeletal muscles. Immediately and on the 14th and 28th days after the operation, contrast enhanced ultrasound (CEU) was used to observe the blood perfusion of the hind limb. On the 28th day postoperatively, immunohistochemistry for CD31 was performed to evaluate the microvascular density (MVD). RESULTS: Real-time PCR showed that Ad-HIF-1alpha significantly increased the expression of HIF-1alpha mRNA (P<0.01) in a dose-dependent manner as compared with that in the saline and Ad-null groups (P<0.01). CEU revealed greater blood perfusion in the hind limb of rabbits in association with increased dose of Ad-HIF-1alpha (P<0.05 or P<0.01); similar changes in the MVD was observed following Ad-HIF-1alpha injections as shown by immunohistochemistry (P<0.05 or P<0.01). No significant differences were found either in the blood perfusion or MVD between saline and Ad-null groups (P>0.05). CONCLUSION: Ad-HIF-1alpha can dose-dependently promote the angiogenesis in the ischemic limb of rabbits.
Hindlimb/blood supply , Hypoxia-Inducible Factor 1, alpha Subunit/genetics , Ischemia/physiopathology , Neovascularization, Physiologic/drug effects , Recombinant Proteins/administration & dosage , Adenoviridae/genetics , Adenoviridae/metabolism , Animals , Female , Genetic Therapy , Hypoxia-Inducible Factor 1, alpha Subunit/biosynthesis , Ischemia/drug therapy , Male , Rabbits , Random Allocation , Recombinant Proteins/biosynthesis , Recombinant Proteins/genetics
OBJECTIVE: To study the effect of propofol at different effect-site concentrations on approximate entropy (ApEn) of transient evoked otoacoustic emission (TEOAE) signals in adults and investigate the possibility of using ApEn for monitoring anesthesia depth. METHODS: Fifteen ASA class I or II patients (aged 18-49 years with normal hearing) undergoing elective surgery under general anesthesia were enrolled in this study. Anesthesia was maintained with target-controlled infusion of propofol. With the effect-site concentrations of 1, 2, 3 and 4 microg/ml, TEOAE signals were monitored and recorded before and after anesthesia. ApEn of TEOAE in 4 frequency ranges (0-2, 1-3, 2.5-4.5, and 4-6 kHz) were calculated using MATLAB software. RESULTS: The ApEn of TEOAE in different frequency ranges showed no significant differences at the same effect-site concentration of propofol, or at different effect-site concentrations in the same frequency range (P>0.05). CONCLUSION: Anesthesia with propofol at different effect-site concentrations does not obviously affect ApEn of TEOAE signals in adults, and ApEn can not be used as the indicator for evaluating the depth of anesthesia.
Anesthetics, Intravenous/pharmacology , Otoacoustic Emissions, Spontaneous/drug effects , Propofol/pharmacology , Adolescent , Adult , Entropy , Female , Humans , Male , Middle Aged , Monitoring, Intraoperative/methods , Young Adult
Alloxan monohydrate was used to induce diabetes in rabbits, which were maintained for a 3-month period with or without daily insulin replacement along with age-matched controls. Isolated right ventricular myocardial strips were used to generate dose-response curves to isoproterenol, forskolin, and Bay K 8644. Basal developed force was significantly elevated in diabetic ventricular strips. While isoproterenol acted as a full inotropic agonist, diabetic preparations revealed a consistent but insignificant decrease in the maximum developed force. While both sensitivity to isoproterenol and beta-adrenoceptor density were decreased in preparations from diabetic rabbits, there was no associated increase in circulating plasma catecholamines. In contrast, forskolin and Bay K 8644 were partial agonists in control preparations but full inotropic agonists in diabetic preparations, demonstrating significant increases in maximum developed force. This hyperresponsiveness was not associated with altered calcium channel density. Finally, insulin replacement reduced or prevented all diabetic-related changes. These data indicate that the hyperresponsiveness to forskolin and Bay K 8644 represents an altered utilization of intracellular calcium in the diabetic rabbit, converting them into full agonists similar to isoproterenol. The decrease in sensitivity to isoproterenol correlated with a decrease in beta-adrenoceptor density but not elevated circulating catecholamines as previously observed in diabetic rats.
Diabetes Mellitus/metabolism , Myocardial Contraction/physiology , Myocardium/metabolism , Ventricular Dysfunction, Right/metabolism , 3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethyl-5-nitro-4-(2-(trifluoromethyl)phenyl)-, Methyl ester/pharmacology , Animals , Calcium Signaling/drug effects , Calcium Signaling/physiology , Dose-Response Relationship, Drug , In Vitro Techniques , Male , Myocardial Contraction/drug effects , Protein Binding/drug effects , Protein Binding/physiology , Rabbits
Diphtheria toxin is a single chain exotoxin of 535 amino acids, secreted from beta Corynebacteriophage diphtheriae. Eukaryotic cells, especially tumor cells are very sensitive to DT. Just one or two molecules of DT can kill a cell. On the surface of some tumor cells, such as human myeloma, heptoma, etc, IL-6 receptor has been demonstrated to be expressed at a very-high level. Selective cytotoxicity mediated by IL-6 receptor could be useful in the targeting therapy of these tumors. Based on this strategy, a hybrid protein consisting of DT and IL-6 was constructed, expressed and characterized. IL-6 cDNA was first modified for constructing the fusion protein of DT/IL-6 and the receptor binding domain of DTDNA was replaced by IL-6 cDNA to obtain the expression vector pdeltaDT/TL-6. After induction by IPTG, the fusion protein was expressed successfully, accounting for 20% of the total bacterial protein. The results of SDS-PAGE and Western blot showed that there was a band of about 64 kD. After preliminary purification, the IL-6 receptor competitive binding test and the cytotoxic activity assay of the deltaDT/TL-6 showed that the fusion protein possessed significant cytotoxic activity to U266 cells; while the cells expressing IL-6 receptors at a medium-level was resistant it to a certain degree.
