Biomedical subjects

Jiping Ma

Publications and source records attributed to Jiping Ma.

6 recordsLinked to original sources

PubMed2026

Complete mitochondrial genomic sequence of Lenzites betulinus (Polyporales, Basidiomycota).

Lenzites betulinus is a medicinal fungus in the Polyporaceae. Here, we report the first complete mitochondrial sequencing of this species. The circular genome is 61,288 bp in length, with a GC content of 26.32% and base composition of A (36.98%), T (36.70%), G (12.96%), and C (13.36%). It contains 14 core protein-coding genes (PCGs), 26 tRNA genes, two rRNA genes, and nine intronic ORFs within the cox1 gene. A maximum-likelihood phylogenetic tree based on 14 PCGs from 17 mitochondrial genomes confirmed that L. betulinus clusters within the Polyporaceae, closely related to Trametes and Fomitopsis. This served as a significant reference for ongoing research into other species within the Polyporales order.

Mitochondrial genome↗

PubMed2005

Application of a high-pressure electro-osmotic pump using nanometer silica in capillary liquid chromatography.

A novel designed electro-osmotic pump (EOP) with simple structure was assembled using three 20 cm x 530 microm i.d. fused-silica capillaries packed with 20 +/- 5 nm silica grains for capillary liquid chromatography. It was found that the pump could generate pressures over 20 MPa and several microL/min flow rate for most of the liquids being delivered with the applied voltage less than 10 kV. By increasing the pressure, decreasing the applied voltage and the electrical current, the thermodynamic efficiency was about 1-4%. A practical application of the EOP in a 20cm x 150 microm i.d. 3 microm C18 fused-silica analytical capillary column demonstrated the applicability of the pump.

Chromatography, Liquid↗

PubMed2004

Study on conical columns with different conical angles for semi-preparative liquid chromatography.

The dynamic flow profiles and separation performances in conically shaped preparative liquid chromatographic columns (inlet i.d. larger than outlet i.d.) with three different angles (7, 10 and 15) were studied and compared with cylindrical column of the same length and internal volume. The shapes of dynamic flow profiles were studied by on-column visualization method. The transparent chromatographic columns made of polymethyl methacrylate (PMMA), packed with C18 bonded silica, were immerged into a cubic pool filled with glycerol to eliminate the cylindrical and conical lens effect. The flow profiles of colored iodine solution in the columns were observed clearly using cyclohexane as mobile phase since the refractive indices of C18, column wall and the mobile phase are very close. In the conical column of 15 degrees (20-7 mm i.d.) the mobile phase in the central region migrated slower than in wall region as it moved toward the column outlet, while in the conical column of 7 degrees (17-11 mm i.d.) the mobile phase in the central region migrated faster than in wall region just like in cylindrical column. We found that a plug-like flow profile was generated in the conical column of 10 degrees (18-9 mm i.d.) during the whole migration process. A carmine and brilliant blue mixture was used as a probe to test the separation ability of the columns. The resolutions of the two compounds on the conical column of 7, 10, 15 and on the cylindrical column were 0.6, 1.57, 1.29 and 0.8, respectively.

Benzenesulfonates↗

PubMed2004

Study of an electroosmotic pump for liquid delivery and its application in capillary column liquid chromatography.

A packed-bed electroosmotic pump (EOP) was constructed and evaluated. The EOP consisted of three capillary columns packed in parallel, a gas-releasing device, Pt electrodes and a high-voltage power supply. The EOP could generate output pressure above 5.0 MPa and constant flow rate in the range of nl/min to a few microl/min for pure water, pure methanol, 2 mM potassium dihydrogenphosphate buffer, the buffer-methanol mixture and the pure water-methanol mixture at applied potentials less than 20 kV. The composition of solvent before/after pumping was quantitatively determined by using a gas chromatograph equipped with both flame ionization detector and thermal conductivity detector. It was found that there were no apparent changes in composition and relative concentrations after pumping process for a methanol-ethanol-acetonitrile mixture and a methanol-water mixture. Theoretical aspect of the EOP was discussed in detail. An capillary HPLC system consisting of the EOP, an injection valve, a 15 cm x 320 microm i.d., 5 microm Spherigel C18 stainless steel analytical column, and an on-column UV detector was connected to evaluate the performance of the EOP. A comparative study was also carried out with a mechanical capillary HPLC pump on the same system. The results demonstrated that the reproducibility of flow rate and the pulsation-free flow property of the EOP are superior to that of mechanical pump in capillary HPLC application.

Acetonitriles↗

PubMed2004

[Analysis of volatile oil in Illicium verum fruit by on-line coupled packed capillary liquid chromatography/capillary gas chromatography].

Volatile oil in Illicillm Verum Fruit was analyzed by on-line coupled packed capillary high performance liquid chromatography/capillary gas chromatography (micro-HPLC-CGC). A micro-HPLC column of 250 mm x 0.32 mm i.d. packed with 5 microm cyano-bonded silica stationary phase was used for group separation. n-Hexane/acetonitrile/dichloromethane (80:8:12, v/v) was used as mobile phase at a flow rate of 1.8 microL/min. Five groups of eluents from the micro-HPLC were collected and stored in a multi-loop interface, which were then transferred to a capillary gas chromatograph sequentially for further analysis. A 10 m x 0.53 mm i.d. retention gap connected with a 30 m x 0.53 mm i.d. x 1.0 microm SE-54 analytical column was used for CGC analysis. In-column splitless injection mode was adopted for better quantitation and manipulation of chromatograms. Five chromatograms were obtained and compared with the result of direct CGC analysis of the same sample. It was found that there were at least 3 new compounds that were not found nor separated before by conventional capillary gas chromatography/mass spectrometry method.

Allylbenzene Derivatives↗

PubMed2004

[Interactions between fungal-feeding nematodes and fungi and their effects on soil nitrogen mineralization].

A species of fungal-feeding nematodes (Aphelenchus avenae) and two species of fungi (Micheli corticolus and Moniliaceae sp.) were isolated from an alluvial soil planted with paddy-rice and wheat in subtropical region. In order to approach their interactions and effects on soil nitrogen mineralization, a gnotobiotic microcosm experiment was carried out with four treatments, i.e., 1) soil + fungi-I (M. corticolus), 2) soil + fungi I + Aphelenchus avenae, 3) soil + fungi II (Moniliaceae sp.), and 4) soil + fungi II + Aphelenchus avenae at 22 degrees C for 25 days. The results showed that the individuals of nematode and fungi were increased simultaneously, suggesting that the inoculation of A. avenae stimulated the growth of fungi. The fungal-feeding nematode increased during the initial 20 days of incubation and then decreased slowly, and the individuals of the nematode that fed on Moniliaceae sp. (II) were higher than those fed on M. corticolus (I) (P<0.01). In the first 12 days of incubation, the population of Moniliaceae sp. (II) increased 2.5-3.5 times, while that of M. corticolus (I) increased slower but caught up after the 12th day, and the density reached 5.0-5.7 times higher than the corresponding treatments with only fungi inoculation. The interactions encouraged the soil nitrogen mineralization of all four treatments, as compared with the control. Comparing the treatments with and without fungal-feeding nematode inoculation, the treatments with fungal-feeding nematode had a higher content of soil NH4+-N than those with only fungi inoculations, which indicated that nematode had a greater effect on soil nitrogen mineralization than fungi. As for the two species of fungi, M. corticolus (I) had a greater effect on soil nitrogen mineralization than Moniliaceae sp. (II). It was observed, however, that the nitrification rate declined as compared with the control.

Animals↗