Indole Alkaloids, Synthetic Dimers and Hybrids with Potential In Vivo Anticancer Activity.

Indole, a heterocyclic organic compound, is one of the most promising heterocycles found in natural and synthetic sources since its derivatives possess fascinating structural diversity and various therapeutic properties. Indole alkaloids, synthetic dimers and hybrids could act on diverse targets in cancer cells, and consequently, possess potential antiproliferative effects on various cancers both in vitro and in vivo. Vinblastine, midostaurin, and anlotinib as the representative of indole alkaloids, synthetic dimers and hybrids respectively, have already been clinically applied to treat many types of cancers, demonstrating indole alkaloids, synthetic dimers and hybrids are useful scaffolds for the development of novel anticancer agents. Covering articles published between 2010 and 2020, this review emphasizes the recent development of indole alkaloids, synthetic dimers and hybrids with potential in vivo therapeutic application for cancers.

Comparison of the Rhizosphere Soil Microbial Community Structure and Diversity Between Powdery Mildew-Infected and Noninfected Strawberry Plants in a Greenhouse by High-Throughput Sequencing Technology.

The aim of this study was to compare the microbial community structure and diversity in powdery mildew-infected and noninfected strawberry plant rhizosphere soils in the greenhouse based on variations in the 16S rRNA gene V3-V4 and fungal ITS2 regions by Illumina amplicon sequencing. Powdery mildew infection reduced the number of operational taxonomic units (OTUs) and prokaryotic and fungal community richness/diversity indexes in the rhizosphere soils compared with those in healthy plant soils. Furthermore, 3543 prokaryotic and 581 fungal OTUs were obtained at the 97% similarity level. Proteobacteria, Actinobacteria, Bacteroidetes, Acidobacteria, and Chloroflexi were the dominant bacterial phyla; Woesearchaeota_DHVEG-6, Bathyarchaeota, and Thaumarchaeota were the dominant archaea; and Ascomycota, Basidiomycota, unclassified_fungi, and Zygomycota were the dominant fungal phyla. Their proportions differed significantly among samples. Wolbachia, Devosia, Pseudolabrys, Streptomyces, and Rhizomicrobium were the most abundant bacterial genera; their proportions differed significantly among samples. Most Pseudomonas, Streptomyces, and 'norank' group members might be potential antagonistic microorganisms of powdery mildew pathogens, and Wolbachia and Rickettsia might be pathogen-transmitting vectors. Microascus, Clitopilus, and Ciliophora were the dominant fungi, and their community structures and abundances significantly differed among samples. Microascus, Talaromyces, Zopfiella, and Cryptococcus were relatively more abundant in the powdery mildew-infected strawberry plant rhizosphere soils. Fusarium, Trichoderma, Clitopilus, and 'unclassified' group members may be potential antagonistic populations. The results suggested that powdery mildew-infected strawberry fruits and plants cannot be consumed. This report is the first study to illustrate differences in the rhizosphere soil prokaryotic and fungal communities between powdery mildew-infected and noninfected strawberry plants in a greenhouse.

Extending the Lifespan of Soluble Lead Flow Batteries with a Sodium Acetate Additive.

In this report, we present a method for the construction of a soluble lead flow battery (SLFB) with an extended cycle life. By supplying an adequate amount of sodium acetate (NaOAc) to the electrolyte, a cycle life extension of over 50% is demonstrated for SLFBs via long-term galvanostatic charge/discharge experiments. A higher quality of the PbO2 electrodeposit at the positive electrode is quantitatively validated for NaOAc-added electrolyte by throwing index (TI) measurements. Images acquired by scanning electron microscopy (SEM) also exhibit more integrated PbO2 surface morphology when the SLFB is operated with the NaOAc-added electrolyte. This work indicates that electrolyte modification can be a plausible route to economically enable SLFBs for large-scale energy storage.

Complete genome sequence of Halomonas ventosae virulent halovirus QHHSV-1.

A virulent halovirus QHHSV-1 which lyses Halomonas ventosae QH52-2 originating from the Qiaohou salt mine in Yunnan, Southwest China was characterized. The complete genome of QHHSV-1 is composed of a circular double-stranded DNA of 37,270 base pairs in length, with 66.8% G+C content and 69 putative open reading frames (ORFs), which were classified into five functional groups, including morphogenesis, replication/regulation, packaging, lysis and lysogeny. A putative Cro repressor gene and an integrase gene were found in the genome, showing that QHHSV-1 may utilize a lambda-like repression system under unfavorable conditions. QHHSV-1 is the first report of the whole genome sequence of the virulent Halomonas phage belonging to the family Siphoviridae.

Mongoliibacter ruber gen. nov., sp. nov., a haloalkalitolerant bacterium of the family Cyclobacteriaceae isolated from a haloalkaline lake.

A novel haloalkalitolerant, rod-shaped bacterium, designated strain YIM 4-4T, was isolated from the surface water of the Dugerno lake, a haloalkaline lake in Inner Mongolia. The taxonomy of strain YIM 4-4T was investigated by a polyphasic approach. Strain YIM 4-4T was Gram-stain-negative, strictly aerobic, non-motile and formed red colonies. Optimal growth conditions were 28 °C, pH 8.0-11.0 and 0.5-2 % NaCl. The major respiratory quinone was menaquinone-7 (MK-7). The polar lipid profile was composed predominantly of phosphatidylethanolamine, six unidentified polar lipids, one phospholipid and one aminolipid. The predominant cellular fatty acids (>5 %) were iso-C15 : 0, iso-C17 : 1I/anteiso-C17 : 1B, iso-C16 : 1G, iso-C17 : 0 3-OH, C16 : 1ω7c/C16 : 1ω6c and iso-C16 : 1. The genomic DNA G+C content was 43.0 mol%. 16S rRNA gene sequence analysis indicated that the members of the genera Cecembia, Fontibacter, Aquiflexum and Indibacter of the family Cyclobacteriaceae (phylum Bacteroidetes) were the most closely related, with 16S rRNA gene sequence similarities ranging from 93.6 to 94.2 %. Other members of the family Cyclobacteriaceae showed sequence similarities < 93.0 %. On the basis of phenotypic, chemotaxonomic and phylogenetic properties, strain YIM 4-4T represents a novel species of a new genus, for which the name Mongoliibacter ruber gen. nov., sp. nov. is proposed. The type strain is YIM 4-4T ( = CCTCC AB 2012966T = DSM 27929T).

A novel Halomonas ventosae-specific virulent halovirus isolated from the Qiaohou salt mine in Yunnan, Southwest China.

Although Halomonas phages belonging to the families Myoviridae and Siphoviridae have been reported, no virulent Halomonas siphoviruses are known. In this study, a virulent bacteriophage, QHHSV-1, of the family Siphoviridae that specifically infects H. ventosae QH52-2 was isolated from the Qiaohou salt mine. Restriction analysis indicated that QHHSV-1 is a dsDNA virus with a genome size of 33.5-39.5 kb. Transmission electron microscopy showed that QHHSV-1 is a typical representative of the Siphoviridae, with an icosahedral head (47 nm in diameter) and a non-contractile tail (75 nm in length). We also assessed the adsorption rate of QHHSV-1 for the host bacterium and found significant inhibition after the addition of 10 mM CaCl2. Based on a one-step growth curve, we determined a latent period of 30 min and a burst size of 73 PFU/infected cell. At the optimal pH of 8.0, 25.9 and 15.2 % of the phages survived after a 60-min incubation at 50 and 60 °C, respectively. Phage replication was possible at a wide range of salt concentrations, from 2.0 to 20 % (w/v), with an optimum concentration of 5 %. The survival of QHHSV-1 at different salt concentrations decreased with time and 25 % survival after 25 days at 30 % salt concentration.

Extraction and antioxidant activity of flavonoids of Morus nigra.

Morus nigra has a long history of medicinal use in Chinese medicine, but the study on it is limited, the flavonoids are one of the main biological active substances. In this study, the Morus nigra flavonoids were extracted by ultrasonic and antioxidant activities both in vitro and in vivo were measured. The results showed that hydroxyl radicals clearance rate and superoxide radical anion clearance rate in vitro increased with the concentration of the total flavonoids in the range of 0-1.05 mg/mL and the maximum clearance rate was 80.33% and 87.69%, respectively. After mice were treated with flavonoids, the content of malonaldehyde (MDA) in serum and liver decreased; the activities of superoxide dismutase (SOD) in serum and liver, catalase (CAT) in liver and glutathione peroxidase (GSH-PX) in blood and liver increased; Langhans cells increased in spleen. These results revealed that the Morus nigra flavonoids possessed strong antioxidant activity.

Halomonas qiaohouensis sp. nov., isolated from salt mine soil in southwest China.

Two Gram-stain negative, moderately halophilic, aerobic, motile bacteria, designated strains YIM QH88(T) and YIM QH103, were isolated from the Qiaohou salt mine in Yunnan, southwest China. Cells of the strains were observed to be rod-shaped and produce creamy-coloured colonies. Growth of the two strains was observed at 10-45 °C (optimum 25-37 °C), at pH 6.0-10.0 (optimum 7.0-8.0), and in the presence of 0.5-20 % (w/v) NaCl (optimum 2-6 %). The two strains were found to contain summed feature 8 (C18:1 ω7c/ω6c), C19:0 cyclo ω8c and C16:0 as the major cellular fatty acids. The polar lipids were identified as diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine and unknown phospholipid. The G+C content of the genomic DNA of strains YIM QH88(T) and YIM QH103 were determined to be 64.6 and 64.2 mol%, respectively, and the predominant respiratory quinone detected was ubiquinone 9. Phylogenetic analyses based on 16S rRNA gene sequences indicated that strains YIM QH88(T) and YIM QH103 formed a distinct lineage within the genus Halomonas and were most closely related to Halomonas pantelleriensis DSM 9661(T) with 97.3 and 97.5 % of 16S rRNA sequence similarity respectively. The DNA-DNA hybridization relatedness value for strains YIM QH88(T) and YIM QH103 was 95.2 ± 0.8 %. The levels of DNA-DNA relatedness between each of these two strains and the type strains of phylogenetically closely related Halomonas species were clearly below 70 %. On the basis of their phylogenetic analysis, DNA-DNA hybridization relatedness, phenotypic and chemotaxonomic characteristics, strains YIM QH88(T) and YIM QH103 should be classified as a novel species of the genus Halomonas, for which the name Halomonas qiaohouensis sp. nov. is proposed. The type strain is YIM QH88(T) (=DSM 26770(T) =CCTCC AB 2012965(T)).

Gracilimonas mengyeensis sp. nov., a moderately halophilic bacterium isolated from a salt mine in Yunnan, south-western China.

A facultatively anaerobic, Gram-staining-negative, pale red-pigmented, non-motile, rod-shaped, moderately halophilic bacterium, designated strain YIM J14(T), was isolated from a sediment sample from a salt mine in Yunnan, south-western China. Growth occurred at NaCl concentrations of between 2 % and 15 % (w/v) and optimally with 5-9 % NaCl. The optimum temperature and pH for growth of the strain were 28 °C and pH 7.5. The major cellular fatty acids were iso-C15 : 0, anteiso-C15 : 0 and iso-C17 : 1ω9c/10-methyl-C16 : 0. The polar lipid profile was composed predominantly of diphosphatidylglycerol, phosphatidylcholine and one unknown phospholipid. Minor amounts of other lipids were also detectable. The genomic DNA G+C content was 47.2 mol%. Phylogenetic analysis based on 16S rRNA gene sequence comparisons indicated that strain YIM J14(T) was related to Gracilimonas tropica in the phylum Bacteroidetes. The level of 16S rRNA gene sequence similarity between strain YIM J14(T) and Gracilimonas tropica CL-CB462(T) was 96.9 %. A DNA-DNA hybridization experiment between strain YIM J14(T) and Gracilimonas tropica indicated levels of relatedness of 28 %. Chemotaxonomic data supported the placement of strain YIM J14(T) in the genus Gracilimonas. DNA-DNA hybridization and biochemical and physiological characterization allowed strain YIM J14(T) to be differentiated from Gracilimonas tropica. It is therefore considered to represent a novel species of the genus Gracilimonas, for which the name Gracilimonas mengyeensis sp. nov. is proposed. The type strain YIM J14(T) ( = ACCC 10717(T) = DSM 21985(T)).

Comparative molecular analysis of the prokaryotic diversity of two salt mine soils in southwest China.

While much is known about the microbial diversity in some hypersaline environments, little is known about those of salt mine tunnel soils. The objective of this study was to conduct a comprehensive phylogenetic comparison of the archaeal and bacterial communities present in Yipinglang salt mine (YPL) and Qiaohou salt mine (QH) tunnels differing in salinity and salt composition using 16S rRNA gene clone libraries. Two hundred twenty-eight sequences for QH and 182 sequences for YPL were analyzed by amplified ribosomal DNA-restriction analysis. Libraries revealed 44 bacterial and 57 archaeal different operational taxonomic units belonging to at least 8 bacterial and 3 archaeal divisions, but not all divisions were observed in both salt mines. The bacterial community affiliated with the Bacteroidetes was the most abundant (60% of clones) in QH, while the community in YPL was dominated by δ-Proteobacteria (45% of clones). All archaeal clones from QH were affiliated with Halobacteriaceae. In contrast, in the YPL library, 49% of clones belonged to Halobacteriaceae, 31% of clones related to unclassified archaea, and 21% of clones belonged to Crenarchaeota. Bioinformatic analysis and comparisons showed that the clone libraries were significantly different between two salt mines.

Aliifodinibius roseus gen. nov., sp. nov., and Aliifodinibius sediminis sp. nov., two moderately halophilic bacteria isolated from salt mine samples.

Two rod-shaped, non-motile bacteria were isolated from two separate salt mines in Yunnan, south-western China. These strains, designated YIM D15(T) and YIM J21(T), were Gram-negative and moderately halophilic. The two strains required 6-10 % NaCl (w/v; optimal) for growth. The DNA G+C contents of strains YIM D15(T) and YIM J21(T) were 49.0 mol% and 48.4 mol%, respectively. The predominant isoprenoid quinone was MK-7. The polar lipid profiles of strains YIM D15(T) and YIM J21(T) were composed predominantly of diphosphatidylglycerol, phosphatidylcholine, phosphatidylethanolamine, three unknown polar lipids and one glycolipid. Minor amounts of other lipids were also detectable. The predominant cellular fatty acids were iso-C15 : 0, anteiso-C15 : 0, iso-C17 : 1ω9c/10 methyl-C16 : 0 and C16 : 1ω7c/C16 : 1ω6c. Phylogenetic analysis based on 16S rRNA gene sequence comparisons showed that the two isolates formed a distinct clade with the genus Fodinibius (in the phylum Bacteroidetes) and were related to the species Fodinibius salinus, with sequence similarities of 91.9-92.4 %. Analyses of 16S rRNA gene sequences revealed that strains YIM D15(T) and YIM J21(T) were related to each other (97.3 % sequence similarity). The DNA-DNA hybridization relatedness between the two isolates was 34 %. On the basis of the phylogenetic analysis, DNA-DNA hybridization relatedness, phenotypic and chemotaxonomic characteristics, strains YIM D15(T) and YIM J21(T) should be classified as members of a novel genus and as two novel species, for which the names Aliifodinibius roseus gen. nov., sp. nov. (type strain YIM D15(T) = ACCC 10715(T) = KCTC 23442(T)) and Aliifodinibius sediminis sp. nov. (type strain YIM J21(T) = ACCC 10714(T) = DSM 21194(T)) are proposed.

Starmerella jinningensis sp. nov., a yeast species isolated from flowers of Erianthus rufipilus.

Five yeast strains (Ym24403, Ym24404, Ym24408, Ym24409 and Ym24410(T)) were isolated from different flowers of Erianthus rufipilus (Gramineae), a wild plant growing in the phosphorus-rich region in Yunnan Province, south-western China, and were found to be phenotypically and genetically divergent from currently recognized yeast species. Sequence analysis of the D1/D2 domain of the large subunit rRNA gene revealed that the five strains represented a novel species described as Starmerella jinningensis sp. nov. The type strain is Ym24410(T) (= CBS 11864(T) =CCTCC AY 2011002(T)). Phylogenetic analysis based on the D1/D2 region of the large subunit rRNA gene suggested that S. jinningensis sp. nov. is placed within the Starmerella clade.

[Diversity and heavy-metal tolerance of bacteria isolated from Gejiu tin mining area of Yunnan].

OBJECTIVE: We assessed the culturable bacterial diversity in tin mine area in Gejiu, Yunnan, China, and heavy-metal tolerance of the isolated bacteria. METHODS: Bacterial strains were isolated from the samples by using the culture-dependent method and investigated by using phylogenetic analysis based on 16S rRNA gene sequence comparisons. Representatives of isolates were selected to detect their tolerance against heavy metals of Pb2+ and Cd2+. RESULTS: We isolated 214 bacterial strains from soils by using two media. Based on colony characteristics, we selected 107 representatives of strains for phylogenetic analysis based on 16S rRNA gene sequences. Results showed that 107 isolates belong to 42 genera of 25 families of 12 orders in 5 phyla. The most abundant isolates were within the phylum Proteobacteria (69.2%) and the genus Pseudomonas (24.8%). Among the 107 isolates, at least 2 strains should represent 2 potential novel species. One hundred and five strains were selected to investigate heavy-metal tolerance and results showed that 73.3% and 8.6% isolates could grow under 1000 mg/L Pb2+ and Cd2+, respectively. Most strains were more sensitive to Cd2+ than Pb2+. Isolates from tin mine tunnel adit were more sensitive to Cd2+ or Pb2+ than those from tin tailings area. Moreover, 2 strains (DT47-2A and DT50-1) can grow under both 1000 mg/L Cd2+ and Pb2+. CONCLUSION: There is abundant bacteria as well as source of novel taxa in Gejiu tin mining area. Most of them had the ability of high resistance against heavy-metal Cd2+ or Pb2+.

Roseivivax sediminis sp. nov., a moderately halophilic bacterium isolated from salt mine sediment.

A Gram-negative, facultatively anaerobic, short rod-shaped, heterotrophic bacterium, designated strain YIM D21(T), was isolated from a salt mine in Yunnan province, south-west China. Strain YIM D21(T) formed cream-yellow colonies, was non-motile and moderately halophilic, and tolerated NaCl concentrations of 1-15% (w/v), with optimum growth at 5-10 % (w/v). Growth occurred at 15-42 °C (optimum 28 °C) and at pH 6.5-8.5 (optimum 7.5-8.0). The respiratory quinone was ubiquinone-10 (Q-10). The polar lipids were diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, phosphatidylcholine, three unidentified phospholipids, one unidentified aminolipid and two unidentified lipids. The major fatty acids were C(18:1)ω7c and cyclo C(19:0)ω8c and the DNA G+C content was 67.7 mol%. Phylogenetic analyses revealed that strain YIM D21(T) belongs to the genus Roseivivax. 16S rRNA gene sequence similarities of YIM D21(T) were 95.7, 95.0 and 94.8% with the type strains of Roseivivax halodurans, Roseivivax lentus and Roseivivax halotolerans, respectively. Physiological and biochemical tests allowed phenotypic differentiation of strain YIM D21(T) from closely related species with validly published names. We therefore propose that this isolate represents a novel species, Roseivivax sediminis sp. nov.; the type strain is YIM D21(T) ( = KCTC 23444(T) = ACCC 10710(T)).

[Growth inhibition effect of immobilized pectinase on Microcystis aeruginosa].

To confirm the growth inhibition effect of immobilized pectinase on algae, co-cultivation method was used to investigate the effect of immobilized pectinase on the growth of Microcystis aeruginosa. After co-cultivation, the damage status of the algae was observed through electron microscope, and the effect of immobilized pectase on the physiological and biochemical characteristics of the algae was also measured. The results showed that the algae and immobilized pectase co-cultivated solution etiolated distinctly on the third day and there was a significantly positive correlation between the extent of etiolation and the dosage as well as the treating time of the immobilized pectinase. Under electron microscope, plasmolysis was found in the slightly damaged cells, and the cell surface of these cells was rough, uneven and irregular; the severely damaged cells were collapsed or disintegrated completely. The algal yield and the chlorophyll a content decreased significantly with the increase of the treating time. The measurement of the malondiadehyde (MDA) value showed that the antioxidation system of the treated algal cells was destroyed, and their membrane lipid was severely peroxidated. The study indicated that the immobilized pectinase could efficiently inhibit the growth of M. aeruginosa, and the inhibitory rate reached up to 96%.

Fodinibius salinus gen. nov., sp. nov., a moderately halophilic bacterium isolated from a salt mine.

A novel, moderately halophilic, rod-shaped bacterium, designated strain YIM D17(T), was isolated from a sample of sediment from a salt mine in Yunnan, south-western China. The taxonomy of strain YIM D17(T) was investigated using a polyphasic approach. Strain YIM D17(T) was Gram-stain-negative, strictly aerobic and non-motile and formed pink colonies on marine agar. Optimal growth occurred at 37 °C, pH 7.5-8.0 and in the presence of 10-15 % (w/v) NaCl. The major menaquinone was MK-7. The polar lipid profile was composed predominantly of diphosphatidylglycerol, phosphatidylcholine, phosphatidylethanolamine, one phospholipid, one glycolipid and one aminolipid. Minor amounts of other lipids were also detectable. The predominant cellular fatty acids were iso-C(17 : 1)ω9c/10-methyl-C(16 : 0) (24.0 %), iso-C(15 : 0) (23.6 %) and C(16 : 1)ω7c/C(16 : 1)ω6c (13.8 %). The DNA G+C content was 43.0 mol%. Phylogenetic analysis based on 16S rRNA gene sequence comparisons showed that the isolate formed a distinct clade with the genera Gracilimonas and Balneola (both in the phylum Bacteroidetes) and was related to the species Gracilimonas tropica, Balneola vulgaris and Balneola alkaliphila, with sequence similarities of 85.6 %, 83.0 % and 82.8 % to the respective type strains. On the basis of its phenotypic, chemotaxonomic and phylogenetic features, strain YIM D17(T) represents a novel species of a new genus, for which the name Fodinibius salinus gen. nov., sp. nov. is proposed. The type strain is YIM D17(T) ( = ACCC 10716(T) = DSM 21935(T)).

Litoribacter ruber gen. nov., sp. nov., an alkaliphilic, halotolerant bacterium isolated from a soda lake sediment.

A novel alkaliphilic, halotolerant, rod-shaped bacterium, designated strain YIM CH208(T), was isolated from a soda lake in Yunnan, south-west China. The taxonomy of strain YIM CH208(T) was investigated by a polyphasic approach. Strain YIM CH208(T) was Gram-negative, strictly aerobic and non-motile and formed red colonies. Optimal growth conditions were 28°C, pH8.5 and 0.5-2.5 % NaCl. Phylogenetic analysis based on 16S rRNA gene sequence comparisons showed that the isolate formed a distinct line within a clade containing the genus Echinicola in the phylum Bacteroidetes and was related to the species Echinicola pacifica and Rhodonellum psychrophilum, with sequence similarity of 91.7 and 91.6 % to the respective type strains. The DNA G+C content was 45.1 mol%. The major respiratory quinone was menaquinone-7 (MK-7). The predominant cellular fatty acids were iso-C(17 : 1)ω9c (19.9 %), C(15 : 0) 3-OH (12.1 %), iso-C(17 : 0) 3-OH (11.3 %), summed feature 3 (iso-C(15 : 0) 2-OH and/or C(16 : 1)ω7c; 10.7 %) and C(17 : 1)ω6c (8.7 %). On the basis of the phenotypic, chemotaxonomic and phylogenetic data, strain YIM CH208(T) represents a novel species of a new genus, for which the name Litoribacter ruber gen. nov., sp. nov. is proposed. The type strain of Litoribacter ruber is YIM CH208(T) (=ACCC 05414(T) =KCTC 22899(T)).

[Preliminary study on the safety and pharmacodynamic action of low dose L-asparaginase].

OBJECTIVE: To investigate the safety and therapeutic effect of low dose (1000 U/m(2)) L-asparaginase (L-Asp) in the treatment of children with acute lymphoblastic leukemia (ALL). METHODS: Six patients were treated with low dose L-Asp after previously suffered severe side effects from standard dose L-Asp (5000 - 10,000 U/m(2)). Twenty-eight blood samples were obtained randomly from 5 of them. Plasma asparagine concentration was detected by reverse phase-high performance liquid chromatography (RP-HPLC). RESULTS: All the patients treated with low dose L-Asp showed no any toxic symptoms. The plasma asparagine levels in the patients were all above 5 micromol/L except case 4 (4.91 micromol/L) before receiving L-Asp, and were all decreased below 0.5 micromol/L five days after receiving low dose L-Asp, except case 3 (3.70 micromol/L), the results being like that of receiving standard dose L-Asp. CONCLUSION: Low dose L-Asp has definite efficacy for childhood ALL, while avoids serious side effects from standard dose L-Asp.

[Research on the pharmacokinetics and pharmacodynamics of L-asparaginase during its treatment of childhood acute lymphoblastic leukemia].

OBJECTIVE: To investigate the changes in the activity of Escherichia coli asparaginase (L-asp) and the concentration of asparagines (ASN) in the plasma of the acute lymphoblastic leukemia (ALL) children receiving L-asp containing chemotherapeutic protocol to explore more reasonable usage of L-asp in the treatment of childhood ALL. METHODS: L-asp containing hemotherapy regimen of VDLP was used, in which L-asp (10,000 U/m(2)) was administered intravenously every other day for 10 doses in 15 children with ALL. A total of 340 peripheral blood samples were collected at scheduled time points during the therapy and plasma L-asp activity (by spectrophotometric assay) and asparagines concentration (by RP-HPLC) were measured. RESULTS: During the administration of L-asp, the plasma L-asp activity was increasing gradually peaked after eight doses and then decreased gradually, while the plasma concentration of asparagines maintained in complete or nearly complete depletion status. After the therapy courses finished, a plasma L-asp activity above 100 U/L with asparagines almost complete depletion status was lasting for about seven days. CONCLUSION: The current L-asp containing chemotherapeutic protocols in which L-asp was administered in a dose of 10 000/m(2) intravenously every other day, are efficient enough for the depletion of plasma ASN.