Exogenous stimulation-induced biosynthesis of volatile compounds: Aroma formation of oolong tea at postharvest stage.

Volatile organic compounds (VOCs) are produced by plants responding to biotic and abiotic stresses. According to their biosynthetic sources, induced VOCs are divided into three major classes: terpenoids, phenylpropanoid/benzenoid, and fatty acid derivatives. These compounds with specific aroma characteristics importantly contribute to the aroma quality of oolong tea. Shaking and rocking is the crucial procedure for the aroma formation of oolong tea by exerting mechanical damage to fresh tea leaves. Abundant studies have been carried out to investigate the formation mechanisms of VOCs during oolong tea processing in recent years. This review systematically introduces the biosynthesis of VOCs in plants, and the volatile changes due to biotic and abiotic stresses are summarized and expatiated, using oolong tea as an example.

Effects of Hydrogen Peroxide Produced by Catechins on the Aroma of Tea Beverages.

Hydrogen peroxide has a significant effect on the flavor of tea beverages. In this study, the yield of hydrogen peroxide in (-)-epigallocatechin gallate (EGCG) solution was first investigated and found to be significantly enhanced under specific conditions, and the above phenomenon was amplified by the addition of linalool. Then, an aqueous hydrogen peroxide solution was added to a linalool solution and it was found that the concentration of linalool was significantly reduced in the above-reconstituted system. These findings were verified by extending the study system to the whole green tea infusions. The results suggested that the production of hydrogen peroxide in tea beverages may be dominated by catechins, with multiple factors acting synergistically, thereby leading to aroma deterioration and affecting the quality of tea beverages. The above results provided a feasible explanation for the deterioration of flavor quality of green tea beverages with shelf life.

Phenolic content and radical scavenging capacity of 31 species of ferns.

The total phenolic content of 31 species of fern plants was determined, and their antioxidant activities were assessed by DPPH radical scavenging analysis.

[An analysis of prognostic factors in 80 myelodysplastic syndrome].

OBJECTIVE: To investigate the WHO classification, clinical and hematological features and risk group of International Prognostic Scoring System (IPSS) in patients with myelodysplastic syndrome (MDS). METHODS: The diagnosis and classification of MDS patients were defined according to the WHO classification. The clinical manifestations, hemogram, bone marrow biopsy and prognosis were retrospectively analyzed. RESULTS: The median age at diagnosis of MDS was 47 yrs being younger than that in some foreign reports. The frequency of abnormal karyotype was 35.14% and +8 was the most frequent abnormal karyotype in our study. Eleven of 74 patients transformed into leukemia. Univariate analysis showed that age, chromosome abnormality, percentage of bone marrow blast cells and number of cytopenias were significantly related to prognosis. There was a statistical difference in cum survival rate between IPSS subcategories (P < 0.05) except that between low- and intermediate I-risk subcategory (P > 0.05). There were statistical differences for refractory anemia (RA) vs RA with excess blast (RAEB), refractory cytopenias with multilineage dysplasia (RCMD) vs RAEB and RAEB-I vs RAEB-II (P < 0.05). CONCLUSIONS: There were differences in age of disease onset, distribution of WHO, sub-classification and abnormal karyotype in this cohort of MDS patients as compared with those in Europe and Japan. It is helpful in diagnosis, treatment and prognosis to divide RAEB into RAEB-I and RAEB-II. IPSS was well applicable in Chinese MDS patients.

[A pilot study of spectrum of gene expression of acute leukemia].

OBJECTIVE: To investigate the gene expression of acute leukemia so as to study the pathogenesis of leukemia. METHODS: Five ml of bone marrow was collected from 22 patients with leukemia, 15 males and 7 females, aged 15-86, 17 with acute myelocytic leukemia, 4 with acute lymphocytic leukemia, and 1 with AHL. Mononuclear cells were isolated. Total RNA was extracted and mRNA was purified. DNA microarray technique with 12 848 genes was used to analyze the gene expression profiles. RESULTS: The predicted 45 genes were enormously expressed in 21 patients with acute leukemia, which were consistent with the ALL and AML classification standards reported by Golub and others. 7 genes which were overexpressed in multiple-resistant cell line K562-n/VCR were also overexpressed in 6 cases of refractory acute leukemia. Further analysis showed that 31 genes were upregulated in AML (M(4)-M(6)) and ALL but downregulated in AML (M(1)-M(3)). CONCLUSION: This results support the standard Golub has put forward. The reason that adult patients with ALL and subtypes of AML (M(4)-M(6)) have poorer prognosis in comparison with AMLM(1)-M(3) is attributed to alterations in gene expression. Primary drug resistance may be the major characteristics of refractory leukemia. Analysis of gene expression profile in acute leukemia is significant for classification and prognosis.

[Clinical and experimental study of two cases of myelodysplastic syndromes with double isochromosome 20q- anomaly].

OBJECTIVE: To explore the clinical and laboratory characteristics of two myelodysplastic syndromes (MDS) patients with double isochromosome 20q- anomaly. METHODS: Bone marrow cell chromosome preparations were made with both direct method and short-term culture. Karyotype analysis was performed by R-banding technique, and dual-color FISH (fluorescence in situ hybridization) by using a 20q telomeric probe and a sequence-specific probe for 20q12. RESULTS: The clinical and hematological findings were comparable with diagnosis of MDS. Karyotype analysis showed that both patients had double isochromosome 20q- anomaly: case 1 is 46, XX, der(20)? i(20q-) [6]/46, idem, der (6) i (6p) [1]/47, idem, +der (20)? i (20q-) [3]/47, idem, der(6)i (6p), +der(20)? i (20q-) [20]; case 2 is 45, XY, -7, der (20)? i (20q-) [17]/46, idem, +der(20) ? i(20q-) [3]. Two derivative chromosomes 20 were proved 20q isochromosomes with interstitial deletions by dual-color FISH in one patient. CONCLUSIONS: Double isochromosome 20q- anomaly is a rare recurrent karyotype abnormality in MDS, and signals a poor prognosis.

[Abnormalities of the erythrocyte membrane ultrastructure and the membrane proteins in a patient with HEMPAS, alpha thalassemia and complicated diabetes].

OBJECTIVE: Diagnosis of a case with congenital dyserythropoietic anemia (CDA). METHODS: Routine tests for hemolysis were carried out. The activities of erythrocyte enzymes were measured according to the methods recommended by international committee for standardization in hematology (ICSH). The quantity and quality of erythrocyte membrane proteins were analyzed with 4% - 15% sodium dodecyl sulfate-polyacrylamide gradient gel electrophoresis (SDS-PAGE). The membrane ultrastructure of erythrocyte from bone marrow was observed under transmission electron microscope (TEM). RESULTS: The main results were: (1) Bone marrow morphology revealed erythroid hyperplasia and 0.10 symmetrically binucleated late erythroblasts. The erythrocytes in peripheral blood showed anisocytosis and hypochromia. (2) The intracellular iron was 0.98 and the storage iron was strongly positive in bone marrow. The serum ferritin was 1607 micro g/L. The content of blood sugar was 27.5 mmol/L. (3) Ham test was negative in his own acidified serum but positive in the group-compatible sera. (4) A quick mobile H band was seen in hemoglobin electrophoresis. H inclusion test was positive. (5) SDS-PAGE demonstrated that the migration of band 3 protein of erythrocyte membrane in an electric field was faster (110%) than that of normal controls and the relative contents of band 1, band 3, band 4.1 were reduced to various extent. (6) "Double membrane" with gap and shedding was observes under TEM. CONCLUSIONS: The final diagnosis of the case was CDAII, also called HEMPAS (hereditary erythroblastic multinuclearity with positive acidified serum), accompanied with alpha thalassemia and secondary siderosis and diabetes.

The effect of Nestorone on gonadotropic cells in pituitary of rats.

The implant containing Nestorone is a promising long-acting contraceptive especially suitable for lactating women. In this study, two experiments were designed to observe the effect of Nestorone on the gonadotropic cells in pituitary of rats for analyzing its antiovulation mechanism. In the first experiment, the ED50 of Nestorone on inhibiting ovulation was found to be 1.32 mg/kg. The serum luteinizing hormone (LH) levels were significantly lower 60 h after being treated with Nestorone at 8:30-9:00 a.m. on Day 2 (D2) of estrus. Image analysis showed that the average size of the LH cells in groups treated with Nestorone at 2 or 4 mg/kg was larger than that of the control. In the group treated with 4 mg/kg, most of gonadotropic cells were regular round in shape. And, abundant granules in cytoplasm were found in those cells, which indicated that the LH stored in cells was not released. In the second experiment, the rats were treated with Nestorone at 5 mg/kg at 11:30-12:00 a.m. on D2 of estrus. The normal or higher expression of LHbeta mRNA in pituitary suggested that the synthesis of LH was not inhibited by the treatment with Nestorone. The expression of PR mRNA in pituitary was significantly lower than that of the control at 33 h after treatment. This might be a direct effect of Nestorone, since there were no differences in the serum E2 and P4 levels between the treated and the control group. It is concluded that Nestorone prevents ovulation through inhibition of LH secretion and it has no effect on synthesis of LH. Progesterone receptors in pituitary might be involved in this process, but further study is needed to gain more evidence.