428 results about "Ic50 values" patented technology

The invention discloses a type of amino acid modified curcumin, a synthesis method thereof, and an application thereof. According to the invention, structural modification is carried out upon curcumin by using natural amino acid, such that 1-(4-hydroxy-3-methoxyphenyl)-7-(4-oxyacetyl amino carbobenzoxy-3-methoxyphenyl)-1,6-heptadiene-3,5-diketone which is represented by a general formula (I) is obtained. With an MTT method, evaluation is carried out upon the compound represented by the general formula (I) in the inhabitance of proliferation activities of four cells which are K562, H22, HL60 and S180. IC50 values of the compound represented by the general formula (I) in inhibiting the proliferations of the four tumor cells are calculated. As a result of experiments, with the compound represented by the general formula (I), proliferations of tumor cells can be substantially inhibited. The compound has excellent anti-tumor activity, and can be prepared into anti-tumor medicines.

The invention provides application of dehydrogenated silibinin diether in the preparation of medicaments for preventing and treating leukemia and relates to medical application of lignin flavone silibinin to the prevention and treatment of chronic myeloid leukemia. Particularly, the invention relates to application of dehydrogenated silibinin diether, of which the seventh bit and the twentieth bit are substituted by 1-butylene, or pharmaceutically acceptable salts thereof in the preparation of medicaments for preventing and treating chronic myeloid leukemia. Natural products of the silibinin are treated by simple steps to synthesize the compound. The pharmacological tests prove that the compound can potently inhibit the in-vitro proliferation of human chronic myeloid leukemia cell strains(K562) and adriamycin drug-resistant strains (K562 / ADR), and the IC50 values are 11.9+ / -1.6 micromoles and 15.9+ / -1.2 micromoles respectively.

The invention discloses a compound with an MEK (Mitogen-activated and Extracellular signal-regulated Kinase) inhibiting function as well as a preparation method and application of the compound. The structure of the compound disclosed by the invention is as shown in a formula (I). The preparation method of the compound disclosed by the invention comprises the steps of forming a coumarin ring by adopting a Pechmann reaction mainly and carrying out structural modification of different sites. In the binding experiment of the compound disclosed by the invention and MEK, the binding activity is up to 54.57nM; the anti-proliferation effect IC50 (half maximal inhibitory concentration) value on the melanoma cell A375 is up to 1.23 micrometers; the anti-proliferation effect IC50 value on the colon cancer cell HT-29 is up to 2.13 micrometers; and the activity is higher than that of a positive control U0126. The novel structure type coumarins compound with the MEK inhibiting function shows good MEK binding activity, MEK inhibiting activity, ERK (Extracellular signal Regulated Kinase) pathway inhibiting activity, anti-tumor effect and antiviral effect and has broad application value. The formula (I) is as shown in the specification.

The invention relates to a compound of 5-hydroxycoumarin and pyranocoumarin and synthesis and application thereof. The compound has a structural formula I or II; during preparation, according to the mol portion, under the catalytic action of 2 to 6 portions of SO2-OSO3H(silicon sulfonic acid), 1 to 3 portions of 5-iodine-1 and 3-dihydroxyhenzene and 1 to 3 portions of RCOCH2COOCH2CH3 are condensed to obtain the compound of which the structural formula is iodo-5-hydroxycoumarin; 1 to 4 portions of compound of iodo-5-hydroxycoumarin and 2 to 8 portions of 3-methyl-2-crotonaldehyde or 3-chloro-3-methylbutyne are reacted to generate a compound of iodo-pyranocoumarin; and finally, by coupled reaction, the coumarin compound with the structural formula I or II is generated. The IC50 value of the compound on breast cancer cells MCF-7 reaches 3.3 to 18.3, so that the compound can strongly inhibit the breast cancer cells MCF-7.

The invention discloses coumarin compounds. The preparation method comprises the following steps: extracting from rattan of Derris eriocarpa How by the inventor; according to the detection introduction of thin-layer chromatography, carrying out reversed-phase silica gel column chromatography, carrying out gradient elution by a petroleum ether-ethyl acetate system for further systematic separation, and recrystallizing. The antioxidation activity experiment proves that the compounds 1 have favorable antioxidation actions, the IC50 value for superoxide anion removal activity is less than that of the positive drug control ascorbic acid, the IC50 value DPPH.free radical removal activity has no great difference from the positive drug, and the compounds 1 have excellent antioxidation activity as compared with the coumarin compounds 6,7-dihydroxycoumarin, daphnetin and daphnoretin which are reported in documents. Therefore, the coumarin compounds disclosed by the invention can be used as a pharmaceutical or non-pharmaceutical antioxidant and the like.

The invention provides a loach protein antihypertensive peptide and a preparation method thereof, belonging to the technical field of biology. The antihypertensive short peptide separated and purified from an enzymolysis product of loach protein has high activity in inhibiting angiotensin converting enzyme (ACE). The preparation method provided by the invention comprises the following steps of: carrying out enzymolysis on the loach protein to prepare an enzymolysis liquid; separating and purifying the antihypertensive peptide from the enzymolysis liquid; and sequencing the antihypertensive peptide. The invention combines a modern enzyme engineering technique and a peptide purifying and identifying technique, deep development and utilization on the loach protein are utilized, and a novel-sequence short peptide Leu-Glue-Tyr with high ACE inhibiting activity is found; and the novel loach protein antihypertensive peptide provided by the invention has high ACE inhibiting activity and has an IC50 value of 0.103 mg / mL.

The invention belongs to the technical field of biological pharmacy, and in particular relates to suppressive activity detection of tetrahydroxy norathyriol on protein-tyrosine-phosphatase (PTP) 1B, improvement of resistance function of insulin and accpication in medicament for PTP1B related diseases. Proved by in vitro enzyme suppression experiments, the invention testifies that mango aglycone is the competitive suppressant of restructuring humanized PTP1B with IC50 value being 9.2 mu m; mango aglycone can ensure the sensitivity of C57BL / 6 normal mouse and ob / ob diabetes model mouse on insulin to be obviously improved, and reduce blood sugar of experimental animals, which suggests that mango aglycone is a novel suppressant of PTP1B, and can be taken as potential lead compound to be applied in preparing medicament for curing insulin resistance related diabetes, obesity and other metabolic syndrome, tumor and other PTP1B related diseases.

The invention discloses a citrus fruit fly odorant binding protein-based attractant screening method belonging to the technical field of bioengineering. The citrus fruit fly odorant binding protein-based attractant screening method comprises the following steps of: collecting the total RNA (Ribonucleic Acid) of antennae of a citrus fruit fly; obtaining the overall length of a citrus fruit fly odorant binding protein through RT-PCR (Reverse Transcription-Polymerase Chain Reaction); constructing a prokaryotic expression vector of the citrus fruit fly odorant binding protein; inducing the expression of a citrus fruit fly recombinant odorant binding protein through IPTG (isopropyl-beta-d-thiogalactoside), and purifying the citrus fruit fly recombinant odorant binding protein through a nickel sepharose gel affinity column; obtaining a conjugation reaction spectrum of the citrus fruit fly recombinant odorant binding protein and a host fruit odor volatile matter through a competitive fluorescence combing method, wherein a dissociation constant (KD) is lower than below 10 mu mol / L host fruit smell; and the IC 50 value of fluorescence competition is less than 30 mu mol / L, determining a host fruit smell attractant suitable for the citrus fruit fly. The invention provides a new strategy for screening and designing a citrus fruit fly odorant host fruit smell odor information attractant formula.

The invention relates to a hydroxypropionic acid compound and a preparation method thereof and a medical application, in particular to a (S)-2-hydroxypropionic acid-(3,4-dihydroxy phenyl) ethyl ester compound separated from medicinal blaps rynchopetera fairmaire, an extraction, separation and preparation method of the compound and an medical application of the compound to preparation of antioxidants. The compound has biological activities remarkably removing DPPH (1,1-diphenyl-2-picryhydrazyl), IC50 value of the compound removing the DPPH is 9.99+-1.61 microgrammes / milliliters and is equivalent to positive control vitamin C (IC50 value is 6.92+-0.89 microgrammes / milliliters). The compound shown as the formula (I) has novelty and great potential developing into novel antioxidants and can be expectedly developed into the antioxidants preventing and treating physiological changes or diseases related to free radicals.

The invention relates to a hybridoma cell strain secreting thiamethoxacin monoclonal antibody and application thereof, belonging to the field of food safety immunodetection. The accession number of the hybridoma cell strain is CGMCC No. 14699. According to the invention, a complete Freund's adjuvant is used for primary immunization of a BALB / c mouse, then an incomplete Freund's adjuvant is used for booster immunization three times, and a thiamethoxam complete antigen containing no adjuvant is used for impact immunization once, so the BALB / c mouse is immunized; and then the high-titer low-IC50spleen cells of the immunized mouse are fused with mouse myeloma cells by using a PEG method, and then the cell strain is obtained through indirect competitive ELISA screening and subcloning three times. The monoclonal antibody secreted by the cell strain has good specificity and detection sensitivity (with an IC50 value of 0.81 ng / mL) to thiamethoxam and can be used for detection of thiamethoxamresidues in food.

The invention discloses a ruthenium complex for inhibiting DNA topoisomerase, which has a molecular formula of [RuL2(PZPP)]Cl2, wherein L is 2,2-bipyridine or 1,10-o-phenanthroline, and PZPP is 3-(2-pyrazinyl)-1,2,4-triazolo[4,5-e]pyrene. The invention also provides the preparation method of the ruthenium complex. The invention further provides a compound 3-(2-pyrazinyl)-1,2,4-triazolo[4,5-e]pyrene obtained in the preparation process of the ruthenium complex. The invention also discloses the application of the ruthenium complex for inhibiting DNA topoisomerase in the preparation of anticancer drugs. The ruthenium complex for inhibiting DNA topoisomerase has good water solubility and has double effects on inhibiting type-I DNA topoisomerase and type-II DNA topoisomerase, and both of the IC50 values are less than 1 muM. The ruthenium complex has wide application prospect.

The invention discloses a monoclonal antibody capable of identifying T-2 and HT-2 toxin. The monoclonal antibody is secreted by a hybridoma cell T-2, which is preserved in China Center for Type Culture Collection, and has a preservation number of CCTCC NO:C201189. The invention also discloses an enzyme-linked immunosorbent assay method and a kit for detecting T-2 and HT-2 toxin, and application thereof to detection of HT-2 and T-2 toxin. Compared with prior art, the monoclonal antibody prepared by the invention has high identification sensitivity, good antibody specificity, IC50 values of 1.46 mug / L and 26.26 mug / L; the enzyme-linked immunosorbent assay method and the kit established by the invention have high detection precision and good accuracy; and a sample treatment method is simple and beneficial for rapid screening.

The invention discloses a rabbit monoclonal antibody based ciprofloxacin residue analysis enzyme-linked immune adsorption kit. In the ciprofloxacin detection, the IC50 value of the kit is 1.41ng / mL, the linear fitting equation of an inhibition ratio curve is y = 0.0239x - 1.3159, the detection range is between 0.19 and 10ng / mL, and the lowest detection limit is 0.095ng / mL. The ciprofloxacin antibody in the kit has higher specificity, and has lower crossing-over rate with other quinolone micromolecules; and the cross reaction rates between the ciprofloxacin antibody and enrofloxacin, ofloxacin, norfloxacin, fleroxacin or pefloxacin are 28.8 percent, 13.1 percent, 11 percent, 22.6 percent and 20.4 percent respectively. The ciprofloxacin antibody has no cross reaction with other antibiotics and sulfanilamide medicaments. The kit is suitable for detecting ciprofloxacin residue in samples of milk, urine and the like. The kit can detect samples on a large scale at the same time, is convenient and quick, has quite important realistic significance for on-site supervision and trace analysis, meanwhile greatly reduces the detection cost, and has potential economic value.

The invention belongs to the field of medical compounds and relates to a salicyloyl anilines compound as well as a preparation method and application in preparing an anti-cancer medicine. According to the method disclosed by the invention, the salicyloyl aniline is taken as a parent and different side-chain substituent groups are introduced into a benzene ring of the parent to prepare the salicyloyl anilines compound of the following formulas, wherein in the formulas, R1, R2, R3 and R4 are defined as an specification. Compared with the Lapatinib, the prepared salicyloyl anilines compound represents that the IC50 value is obviously reduced or is at least equal to that of the Lapatinib. The experiment shows that the salicyloyl anilines compound provided by the invention has an obvious inhibition effect on tumor cells, especially ovarian cancer cells so that the salicyloyl anilines compound can be further used for preparing antitumor medicines. The chemical formula of the salicyloyl anilines compound is represented by the following formulas.

The invention provides a yak bone protein peptide with an ACE inhibiting function and a preparation method and application thereof. The yak bone protein peptide is prepared from enzymatically hydrolyzed yak bone protein by multiple-step enzymatic hydrolysis by compound protease, and the compound protease consists of alkali protease, papain, trypsin and flavourzyme. The yak bone protein peptide provided by the invention has an excellent ACE inhibiting function, the ACE inhibiting activity (IC50 value) is smaller than 0.32mg / mL, and the yak bone protein peptide can be used as an ACE inhibitor to be applied to special foods and nutritional foods. The preparation method of the yak bone protein peptide provided by the invention is simple, the whole processing course is not added with acid or alkali for regulating the pH value, and the product maintains good functional characteristics and is easier to realize industrialized production.

The present invention provides 2-hydroxy-3-amino methylene-4, 6-dibubstituted chalcone derivative with the structural general expression as shown. The preparation process includes the following steps: Lewis acid catalyzed reaction of compound I and anhydrous methy1cyanide inside inert solvent to obtain intermediate trihydroxy acetophenone amide hydrochloride; further acid hydrolysis to obtain compound II; selective etherification with alkylation reagent under alkaline cddn to obtain compound III; condensation with aromatic aldehyde under alkaline condition to obtain compound IV; and reaction with secondary amine in the presence of acid and formaldehyde to produce destination compound V. The present invention provides completely new structure compounds with powerful tumor cell inhibiting effect and IC50 value up to 0.8 micron, and capable of being used in preparing antitumor medicine.

The invention discloses a platinum (II) metal complex for specifically inhibiting proliferation of a lung carcinoma cell, and a synthesis method and an application thereof. The structural formula of the platinum (II) metal complex for specifically inhibiting the proliferation of the lung carcinoma cell is as shown in formula (I). The synthesis method of the platinum (II) metal complex for specifically inhibiting the proliferation of the lung carcinoma cell includes: fetching a compound as shown in following formula (II) and dichlorodi(dimethyl sulfoxide)platinate(II), dissolving the compound and the dichlorodi(dimethyl sulfoxide)platinate(II) in polar solvent, reacting under a heating or non-heating condition, and then obtaining reaction liquid containing the target product. The metal complex can specifically inhibit the proliferation of the lung carcinoma cell NCI-H460, and IC50 (half maximal inhibitory concentration) value is up to 5.01+ / -0.54 microns, and the metal complex embodies good potential pharmaceutical value, and is hopefully used in preparation of specific lung cancer resisting pharmaceuticals. The formula (I) and the formula (II) show structures as follows.

The invention discloses an mbr-FPGS (folylpolyglutamate synthetase) efficient expression vector. In the vector, a plasmid vector is pEGFP-C1, an mbr sequence with the length of 279bp is contained on the upstream of a cytomegalovirus (CMV) promoter of the pEGFP-C1, and a protein coding region of FPGS is contained between two restriction enzyme cutting sites, namely Hind III and EcoR I of the pEGFP-C1; and the mbr sequence is shown in a sequence table 2. An IC50 result of the constructed mbr-FPGS efficient expression plasmid which is measured by a Western Blot experiment and a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) experiment proves that: the FPGS expression level of the mbr-FPGS efficient expression plasmid is improved by 30 percent (p is less than 0.05) compared with that of an FPGS comparison plasmid, the mbr-FPGS efficient expression plasmid can obviously improve the sensitivity of cancer cells to methotrexate (MTX) and has a certain dose-time dependence,and the IC50 value (72h) of an mbr-FPGS efficient expression group cell is 2.63ng / ml which is one seventh (p is less than 0.05) of the IC50 value (19.01ng / ml) of a comparison group cell approximately.

The invention discloses a novel osthole derivative which is a compound having a structure of formula I or formula II. The invention further discloses a preparation method of the osthole derivative comprising that the osthole derivative as an initial raw material undergoes a hydrogenation reduction reaction; a product of the hydrogenation reduction reaction is reacted with N-bromo succinimide (NBS) and then bromine is introduced into the product; and the bromination product undergoes a coupling reaction with multiple boracic acids in the presence of palladium catalysts and thus a series of osthole derivatives are obtained. The invention further discloses an application of the osthole derivative in preparing medicine for treating breast cancer, wherein the osthole derivative exhibits IC50 values of 0.2 to 50 micrometers for inhibitions of breast cancer cells MCF-7 and thus has strong inhibition effects for breast cancer cells MCF-7.

The invention discloses a method for quickly detecting microbial drug resistance and a special microfluidic chip. The microfluidic chip is composed of a polydimethylsiloxane layer, an agarose layer and a transparent board which are orderly overlapped; two through holes are formed in the polydimethylsiloxane layer; the agarose layer is composed of the agarose and the microorganism and supported by the transparent board. The in-situ cultivation, gradient exposure and real-time observation of the microorganism can be realized by the microfluidic chip; the structure and operation are simple, the microfluidic chip can be quickly prepared and checked and is conveniently used for the ordinary biology lab; the injection pump is not needed; the microorganism does not need the fluorescence and the common microorganism is used; the key part of the chip can be used repeatedly, the cost is low and the special microfluidic chip is suitable for daily operation. The growing status of the microorganism in the medicines different in concentration can be observed in real time and the inhibition characters to the microorganism from the medicines can be quickly obtained; the minimum inhibition concentration (MIC) value, the half inhibitory concentration IC50 and the whole inhibition curve are achieved.

The invention discloses a preparation method of sargassum oligosaccharide. The preparation method comprises the steps that fine polysaccharide obtained through degreasing and deproteinizing of sargassum is taken as a raw material, ultrasonic treatment is utilized, alginate lyase, mannase, xylanase and pectinase are sequentially added to perform enzymolysis on the polysaccharide, the polysaccharide which is not degraded fully is removed through an ethyl alcohol sedimentation method, supernate is centrifuged and screened by a molecular sieve to obtain retained matter, freeze drying is performed, and the sargassum oligosaccharide is prepared. The prepared sargassum oligosaccharide has the high inhibitory activity on alpha-glucosidase, the IC50 value is 4.82 mg / mL, the dose dependency is presented, and meanwhile the obvious promoting effect on glucose consumption of insulin-resistant HepG2 cells is achieved. According to the preparation method, the non-specific commercial enzymes are adopted, the process route is simple and reasonable, the method is suitable for industrialization, the preparation amount of the hypoglycemic active oligosaccharide is increased, and meanwhile the enzyme consumption and production cost are reduced; the method is an effective method for preparing the sargassum oligosaccharide and can be applied to hypoglycemic drugs, health care products and food.

The present invention is process of preparing avenin ACE inhibiting peptide (ancovenin), and belongs to the field of oat deeply processing technology. The present invention prepares four kinds of avenin ancovenins, avenin ancovenin A, avenin ancovenin B, avenin ancovenin C and avenin ancovenin D, with oat bran as material, and through crushing, enzyme pre-treatment, alkali extraction, centrifugal separation, isoelectric point supernatant precipitation, water adding homogenizing of the precipitate, alkali proteinase adding hydrolysis, centrifuging to obtain supernatant and chromatographic separation. These avenin ancovenins have their structures identified and the semi-inhibiting rate IC50 measured. The process is reasonable and possesses importance in comprehensive utilization of oat resource.

The invention relates to a vancomycin-resistant monoclonal antibody hybridoma cell strain and application thereof, and belongs to the field of food safety immunodetection. The vancomycin-resistant monoclonal antibody hybridoma cell strain 2A1 is preserved in the General Microbiological Center of China General Microbiological Culture Collection Center (CGMCC) with the preservation number of CGMCC No.10869; the vancomycin-resistant monoclonal antibody is produced by the hybridoma cell strain 2A1 with the preservation number of CGMCC No.10869 through secretion. The monoclonal antibody produced by the hybridoma cell strain through secretion has an IC50 (half maximal inhibitory concentration) value of 1.45 ng / mL to vancomycin, has an IC50 value of 3.98 ng / mL to demethylvancomycin, and further can be used for simultaneous detection of vancomycin and demethylvancomycin in food.

The invention provides tripeptides with angiotensin converting enzyme inhibition activity. The tripeptides with angiotensin converting enzyme inhibition activity are novel milk tripeptides. One of the tripeptides with angiotensin converting enzyme inhibition activity respectively has an amino acid sequence of TDY, FKI, LSK, LKY, IKF, IPA, IKY, LSF, LKP, WYY, RVY, IKQ or MMA. The invention also provides a composition containing an active ingredient of at least one of the tripeptides. The invention also provides a use of the tripeptides in preparation of drugs or functional foods for reducing angiotensin converting enzyme activity. The tripeptides provided by the invention have high angiotensin converting enzyme (ACE) inhibition activity in vitro, wherein under the concentration of 2.5 millimoles per liter, an ACE activity inhibition rate is above 58% and an optimal IC50 value is 0.86 micro-millimoles per liter.

The invention discloses a thiacloprid and acetamiprid monoclonal antibody hybridoma cell strain GW and application thereof, and belongs to the field of food security immunodetection. Thiacloprid and acetamiprid complete antigen of the strain is uniformly mixed with an equal amount of QuickAntibody-Mouse 5W adjuvant, and is injected to BALB / c mice through leg muscle. The dosage is 100mu g / mouse for the first time of immunization, the dosage is 50[mu]g / mouse for multiple times of intensified immunization, the immunization is implemented at an interval of 21 days, and thiacloprid and acetamiprid complete antigen (25[mu]g / mouse, without adjuvant) is adopted for immunization impact for the last time. Splenocyte of high-potency low IC50 mice is taken and fused with mouse myeloma cells by using a PEG method, indirect competitive inhibition enzyme-linked immunosorbent assay is adopted for screening, and three times of subcloning is implemented, so as to obtain the hybridoma cell strain. A monoclonal antibody secreted from the cell strain has relatively good specificity and detection sensitivity (the IC50 values are 0.1ng / mL and 0.4ng / mL respectively) for thiacloprid and acetamiprid, detection on the residual amounts of thiacloprid and acetamiprid in water, fruits and vegetables and cereals can be achieved, conditions are provided for immunodetection on thiacloprid and acetamiprid residues in food can be provided, and practical use values can be made.

A group of compounds that inhibit HIV replication by blocking HIV entry was identified. Two representative compounds, designated NB-2 and NB-64, inhibited HIV replication (p24 production) with IC50 values <0.5 μg / ml. It was proved that NB-2 and NB-64 are HIV entry inhibitors by targeting the HIV gp41 since: 1) they inhibited HIV-mediated cell fusion; 2) they inhibited HIV replication only when they were added to the cells less than one hour after virus addition; 3) they did not block the gp120-CD4 binding; 4) they did not interact with the coreceptor CXCR4 since they failed to block anti-CXCR4 antibody binding to CXCR4-expressing cells; 5) they blocked the formation of the gp41 core that is detected by sandwich enzyme linked immunosorbent assay (ELISA) using a conformation-specific MAb NC-1; 6) they inhibited the formation of the gp41 six-helix bundle revealed by fluorescence native-polyacrylamide gel electrophoresis (FN-PAGE); and 7) they blocked binding of D-peptide to the hydrophobic cavity within gp41 coiled coil domain, modeled by peptide IQN17. These results suggested that NB-2 and NB-64 may interact with the hydrophobic cavity and block the formation of the fusion-active gp41 coiled coil domain, resulting in inhibition of HIV-1 mediated membrane fusion and virus entry.

The invention discloses a screening method of small-molecule inhibitor capable of inhibiting proliferation of toxoplasma gondii. The method utilizes an Alphascreen experiment to primarily select 11 small-molecule inhibitors and one small-molecule accelerant, and the 12 drugs are used for clinical treatment. The 12 drugs are further screened at the cellular level, a plaque experiment proves that GSK J4HCL apparently inhibits the proliferation of toxoplasma gondii, and the value EC50 of the GSK J4HCL to toxoplasmagondii is determined to be about 4.5 muM by virtue of intracellular proliferation experiment. The AlphaScreen competitive inhibition experiment evaluates that the value IC50 of the GSK J4HCL for inhibiting the interaction of TgAtg8 to TgAtg3 is 11.01 muM. The CCK8 experiment is usedfor proving that the value IC50 of the drug for inhibiting the growth of a host cell is 34.359 muM which is far greater than the value EC50 of the drug for the insect, which illustrates that the GSKJ4HCL is a low-toxicity and high-efficiency drug for resisting the toxoplasma gondii.