Reduced microbial stability in the active layer is associated with carbon loss under alpine permafrost degradation.

Permafrost degradation may induce soil carbon (C) loss, critical for global C cycling, and be mediated by microbes. Despite larger C stored within the active layer of permafrost regions, which are more affected by warming, and the critical roles of Qinghai-Tibet Plateau in C cycling, most previous studies focused on the permafrost layer and in high-latitude areas. We demonstrate in situ that permafrost degradation alters the diversity and potentially decreases the stability of active layer microbial communities. These changes are associated with soil C loss and potentially a positive C feedback. This study provides insights into microbial-mediated mechanisms responsible for C loss within the active layer in degraded permafrost, aiding in the modeling of C emission under future scenarios.

Antipsychotic drugs induce vascular defects in hematopoietic organs.

Antipsychotic agents are clinically utilized to treat schizophrenia and other mental disorders. These drugs induce neurological and metabolic side effects, but their influence on blood vessels remains largely unknown. Here, we show that haloperidol, one of the most frequently prescribed antipsychotic agents, induces vascular defects in bone marrow. Acute haloperidol treatment results in vascular dilation that is specific to hematopoietic organs. This vessel dilation is associated with disruption of hematopoiesis and hematopoietic stem/progenitor cells (HSPCs), both of which are reversible after haloperidol withdrawal. Mechanistically, haloperidol treatment blocked the secretion of vascular endothelial growth factor A (VEGF-A) from HSPCs. Genetic blockade of VEGF-A secretion from hematopoietic cells or inhibition of VEGFR2 in endothelial cells result in similar vessel dilation in bone marrow during regeneration after irradiation and transplantation. Conversely, VEGF-A gain of function rescues the bone marrow vascular defects induced by haloperidol treatment and irradiation. Our work reveals an unknown effect of antipsychotic agents on the vasculature and hematopoiesis with potential implications for drug application in clinic.

An atlas of bacterial secondary metabolite biosynthesis gene clusters.

Bacterial secondary metabolites are rich sources of novel drug leads. The diversity of secondary metabolite biosynthetic gene clusters (BGCs) in genome-sequenced bacteria, which will provide crucial information for the efficient discovery of novel natural products, has not been systematically investigated. Here, the distribution and genetic diversity of BGCs in 10 121 prokaryotic genomes (across 68 phyla) were obtained from their PRISM4 outputs using a custom python script. A total of 18 043 BGCs are detected from 5743 genomes with non-ribosomal peptide synthetases (25.4%) and polyketides (15.9%) as the dominant classes of BGCs. Bacterial strains harbouring the largest number of BGCs are revealed and BGC count in strains of some genera vary greatly, suggesting the necessity of individually evaluating the secondary metabolism potential. Additional analysis against 102 strains of discovered bacterial genera with abundant amounts of BGCs confirms that Kutzneria, Kibdelosporangium, Moorea, Saccharothrix, Cystobacter, Archangium, Actinosynnema, Kitasatospora, and Nocardia, may also be important sources of natural products and worthy of priority investigation. Comparative analysis of BGCs within these genera indicates the great diversity and novelty of the BGCs. This study presents an atlas of bacterial secondary metabolite BGCs that provides a lot of key information for the targeted discovery of novel natural products.

Thiazolidin-2-cyanamides derivatives as novel potent Escherichia coli ß-glucuronidase inhibitors and their structure-inhibitory activity relationships.

Gut microbial ß-glucuronidases have the ability to deconjugate glucuronides of some drugs, thus have been considered as an important drug target to alleviate the drug metabolites-induced gastrointestinal toxicity. In this study, thiazolidin-2-cyanamide derivatives containing 5-phenyl-2-furan moiety (1-13) were evaluated for inhibitory activity against Escherichia coli ß-glucuronidase (EcGUS). All of them showed more potent inhibition than a commonly used positive control, d-saccharic acid 1,4-lactone, with the IC50 values ranging from 1.2 µM to 23.1 µM. Inhibition kinetics studies indicated that compound 1-3 were competitive type inhibitors for EcGUS. Molecular docking studies were performed and predicted the potential molecular determinants for their potent inhibitory effects towards EcGUS. Structure-inhibitory activity relationship study revealed that chloro substitution on the phenyl moiety was essential for EcGUS inhibition, which would help researchers to design and develop more effective thiazolidin-2-cyanamide type inhibitors against EcGUS.

Sargassum fusiforme Polysaccharides Prevent High-Fat Diet-Induced Early Fasting Hypoglycemia and Regulate the Gut Microbiota Composition.

A low fasting blood glucose level is a common symptom in diabetes patients and can be induced by high-fat diet (HFD) feeding at an early stage, which may play important roles in the development of diabetes, but has received little attention. In this study, five polysaccharides were prepared from Sargassumfusiforme and their effects on HFD-induced fasting hypoglycemia and gut microbiota dysbiosis were investigated. The results indicated that C57BL/6J male mice fed an HFD for 4 weeks developed severe hypoglycemia and four Sargassumfusiforme polysaccharides (SFPs), consisting of Sf-2, Sf-3, Sf-3-1, and Sf-A, significantly prevented early fasting hypoglycemia without inducing hyperglycemia. Sf-1 and Sf-A could also significantly prevent HFD-induced weight gain. Sf-2, Sf-3, Sf-3-1, and Sf-A mainly attenuated the HFD-induced decrease in Bacteroidetes, and all five SFPs had a considerable influence on the relative abundance of Oscillospira, Mucispirillum, and Clostridiales. Correlation analysis revealed that the fasting blood glucose level was associated with the relative abundance of Mucispinllum and Oscillospira. Receiver operating characteristic analysis indicated that Mucispinllum and Oscillospira exhibited good discriminatory power (AUC = 0.745-0.833) in the prediction of fasting hypoglycemia. Our findings highlight the novel application of SFPs (especially Sf-A) in glucose homeostasis and the potential roles of Mucispinllum and Oscillospira in the biological activity of SFPs.

Dose-response relationship between blood lead levels and hematological parameters in children from central China.

BACKGROUND: Lead is a heavy metal that can affect the human hematological system. However, reports are limited on the dose-response relationship between blood lead levels (BLLs) and hematological parameters in children. This study aimed to explore the dose-response relationship between BLLs and hematological measurements among children in China. METHODS: A cross-sectional design was used. A total of 743 children aged 5-8 years were recruited from two counties in central China. The BLLs and blood levels of iron, zinc, and calcium were determined, and hematological parameters were measured. RESULTS: All hematological measurements and BLLs were logarithm-transformed to ensure a normal distribution. The geometric mean of the BLLs of all children was 82.4 µg/L. Forty-one percent of the children had BLLs ≥ 100 µg/L. The lead-poisoning percentages of the children were significantly associated with gender, age, district of residence, and environmental lead exposure level. Multivariate linear regression analyses showed no significant linear correlation between BLL and each hematological parameter among the children with BLLs ≥ 100 µg/L. The analyses also revealed a small increase in red blood cell count (RBC) with increasing BLLs in the BLLs < 100 µg/L group (ß = 0.03, P =  0.048). A negative association was noted between BLLs and blood platelet (PLT) count in the children with BLLs < 100 µg/L (ß = -0.90, P < 0.001). Logistic regression analyses showed that BLLs were significantly associated with decreased hemoglobin (Hb) levels, RBC counts, PLT counts and mean corpuscular hemoglobin (MCH) after adjusting for potential confounders. Such analyses also revealed a dose-response relationship between the BLLs and hematological parameters (Hb level, RBC count, and PLT count). The children with BLLs ≥ 100 µg/L were 2.72, 2.51, and 3.76 times more likely to achieve decreased RBC counts, Hb levels and PLT counts, respectively, compared to those with BLLs < 100 µg/L. Compared with children with BLLs < 100 µg/L, those with BLLs ≥ 100 µg/L were 3.16 and 4.38 times more likely to show decreased Hb levels and PLT counts respectively in the high-level lead-exposure group and 4.33 times more likely to achieve a decreased PLT count in the low-level lead-exposure group. The individuals with BLLs of the highest quartile were 3.65, 5.87, and 29.23 times more likely to exhibit decreased Hb levels, RBC counts, and PLT counts, respectively, than the children with BLLs of the lowest quartile. CONCLUSION: Our findings suggested a negative association between BLLs and hematological indicators (Hb level, RBC count, PLT count and MCH). A strong negative, non-linear dose-response relationship was also showed between BLLs and hematological parameters (Hb level, RBC count, and PLT count).

[Protective effect of Ligustri Lucidi Ait Polysaccharide against lipopolysaccharide-induced inflammatory injury of Sertoli cells in rats].

OBJECTIVE: To explore the effect of Ligustri Lucidi Ait Polysaccharide (LLP) on lipopolysaccharide (LPS)-induced inflammatory injury of Sertoli cells. METHODS: Rat Sertoli cells were isolated and cultured in vitro and then divided into five groups, blank control, LPS, LPS + low-dose LLP, LPS + medium-dose LLP, and LPS + high-dose LLP. After 48 hours of treatment, the proliferation of the cells was detected by CCK-8, their apoptosis determined by FMC, and the levels of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px) activity and malondialdehyde (MDA) in the supernatant of the cell culture medium measured by ultraviolet spectrophotometry. The contents of IL-1α, IL-6 and TGF-ß in the culture medium were detected by ELISA before and after removal of LPS. RESULTS: The proliferation of the cells showed statistically significant differences among different groups (F = 153.93, P < 0.01), markedly reduced in the LPS group as compared with the blank control (P < 0.01), but remarkably increased in the high- and medium-dose LLP groups in comparison with the LPS group (both P < 0.01), and so did the apoptosis of the cells (F = 64.06, P < 0.01), significantly increased in the LPS group as compared with the blank control (P < 0.05), but markedly decreased in the high- and medium-dose LLP groups in comparison with the LPS group (both P < 0.01). Statistically significant differences were also observed among different groups in the levels of SOD (F = 56.07, P < 0.01), CAT (F = 41.57, P < 0.01), GSH-Px activity (F = 238.46, P < 0.01), and MDA (F = 285.31, P < 0.01), with decreased SOD, CAT and GSH-Px activity (P < 0.01) and increased MDA (P < 0.01) in the LPS group as compared with the control, but elevated SOD and CAT in the high- and medium-dose LLP groups and increased GSH-Px activity and decreased MDA concentration in all the three LLP groups in comparison with the LPS group (P < 0.01). Before the removal of LPS, the contents of IL-1α, IL-6 and TGF-ß in the culture medium were markedly higher in the LPS than in the control group (all P < 0.01), that of IL-1α was increased significantly in the high- and medium-dose LLP groups (P < 0.01 and P < 0.05) while those of IL-6 and TGF-ß showed no statistically significant differences in the three LPS groups as compared with the LLP group (P > 0.05). After the removal of LPS, the contents of IL-1α and IL-6 were remarkably reduced (t = 25.26 and 61.43, P < 0.01) and that of TGF-ß increased (t = －18.16, P < 0.01), even more significantly in the LLP+LPS groups (P < 0.01). CONCLUSIONS: Ligustri Lucidi Ait Polysaccharide plays a protective role in LPS-induced inflammatory injury of Sertoli cells by reducing cell apoptosis and regulating the contents of IL-1α, IL-6 and TGF-ß from Sertoli cells in inflammation.

Studies on anti-hepatoma activity of Annona squamosa L. pericarp extract.

This study investigated the anti-hepatoma activity of different extracts from A. squamosa pericarps, phytochemistry of the ethyl acetate (EtOAc) fraction and possible anti-hepatoma mechanism of active constituents. The anti-hepatoma activity of different extracts from A. squamosa pericarps were evaluated by MTT assay against SMMC-7721 cells in vitro and verified by using H22 xenografts bearing mice. Phytochemical investigation of the active pericarp extract was carried out. The pro-apoptosis and cycle arrest effects of active constituents were observed by fluorescent microscope and flow cytometry. Western blot assay was conducted to find the possible anti-hepatoma mechanisms of active constituents. The result showed that EtOAc extract was the active fraction. Two ent-kaurane diterpenoids, named ent-kauran-16-en-19-oic acid and ent-kauran-15-en-19-oic acid, were isolated from the active EtOAc fraction. The pro-apoptosis and G1 phase arrest effects of these diterpenoids were found. Western blot assay showed that ent-kauran-16-en-19-oic acid could activate caspase-3,-8,-9, up-regulate of Bax and down-regulate of Bcl-2.

Anti-arthritic activity of ethanol extract of Claoxylon indicum on Freund's complete adjuvant-induced arthritis in mice.

BACKGROUND: Claoxylon indicum Hassk. (Euphorbiaceae), named Diu Le Bang, have functions of dehumidification and relieving swelling pain, and is used as a folk medicine to treat Rheumatoid arthritis (RA), lumbocrural pain and foot edema in the south of China. The aim of the present study was to investigate the anti-arthritic activity of the ethanol extract of Claoxylon indicum (CIE) on mice with adjuvant induced joint arthritis. METHODS: Adjuvant arthritis was induced in mice by subcutaneous injection of complete Freund's adjuvant into the plantar surface of right hind paw. Arthritis severity was evaluated by arthritic score, hind paws oedema and spleen index, and histological examinations. Serum samples were collected for determination of malondialdehyde (MDA) and alkaline phosphatase (ALP) levels. The expression of interleukin-1 beta (IL-1ß) and tumor necrosis factor alpha (TNF-α) in the specimens of knee joints was determined by standard immunohistochemical techniques. RESULTS: CIE administration (0.4 and 0.8 g/kg) suppressed the inflammatory responses in the joints of adjuvant-induced arthritis (AIA) mice, suggested by the modulatory effects on paw swelling, hyperplasia of lymphatic tissues and synovial membrane. It also decreased the levels of MDA and ALP in serum and downregulated the expression of IL-1ß and TNF-α in the arthritic joints of AIA mice. CONCLUSION: These results suggested that CIE possessed substantial anti-arthritic activity due to immumodepression and regulation of cytokines. CIE may be a potential candidate for the treatment of RA.

A visual multiplex PCR microchip with easy sample loading.

There is an urgent demand for affordable, rapid and easy-to-use technology to simultaneously detect many different DNA targets within one reaction. Conventional multiplex PCR is an effective methodology to simultaneously amplify different DNA targets. However, its multiplicity is limited due to the intrinsic interference and competition among primer pairs within one tube. Here, we present an easy multiplex PCR microchip system, which can simultaneously detect 54 targets. The design of the microchip is quite simple. There is a microchannel connected with multiple underlying parallel microwells. And every microchannel has an inlet/outlet for loading PCRmix. The surface of the microchannel is hydrophobic and the inner surface of the microwell is hydrophilic, which enables us to load and separate the PCRmix into different microwells simultaneously. Different primer pairs and low melting agarose are pre-fixed in different microwells, and the microchip is assembled with top glass. The PCRmix is loaded into inlets and then mineral oil is sequentially pipetted into channels to push the PCRmix into all microwells and subsequently mineral oil fills the channels to avoid cross contaminations. After the PCRmix is loaded, it would be placed on a plat thermal cycler for PCR. During PCR, the low melting gel in the well is liquid and after PCR it would be solidified due to temperature changes. When PCR is completed, a nucleic acid dye is introduced into channels and then results are visualized by a home-made, potable UV detector. In our platform we successfully detected seven frequently used targets of genetically modified (GM) organisms. The results demonstrate that our platform has high flexibility and specificity. Due to the excellent performance of this technology, we believe that it can be applied to multiple nucleic acid detection fields including GM organisms.

[Role of TGF-ß1 in Sertoli cells and tight junction].

OBJECTIVE: To explore the role of TGF-ß1 in the proliferation and apoptosis of Sertoli cells and its effect on the expressions of tight junction-related proteins and genes in rats. METHODS: Rat Sertoli cells were isolated in vitro, primarily cultured, and divided into groups A (blank control), B (TGF-ß1 receptor blocker), C (TGF-ß1), and D (TGF-ß1 + receptor blocker). The proliferation and apoptosis of the cells were detected by CCK-8 and flow cytometry, respectively. After establishment of the dual-chamber model for the primary culture of Sertoli cells, the trans-epithelia electrical resistance (TER) value was measured and the relative expressions of Occludin, ZO-1 and Claudin Ⅱ determined by RT-PCR and Western blot. RESULTS: The OD value of the proliferation of the Sertoli cells was markedly higher in group C than in groups A and D (0.79 ± 0.04 vs 0.66 ± 0.05 and 0.68 ± 0.02, P<0.05), with statistically significant differences among the four groups (F = 5.05, P <0.05). However, no remarkable difference with found among the four groups in the apoptosis rate of the cells (F = 1.13, P >0.05). The TER value was dramatically decreased in group C as compared with groups A and D (ï¼»176.37 ± 16.61ï¼½ vs ï¼»281.42 ± 9.83ï¼½ and ï¼»254.37 ± 13.55ï¼½ /cm2, P<0.01), with statistically significant differences among the four groups (F = 38.99, P<0.01). There were no remarkable differences among the four groups in the mRNA expressions of ZO-1 and Claudin Ⅱ (F = 0.49 and 0.93, P>0.05) or their protein expressions (F = 0.28 and 1.31, P>0.05). Both the mRNA and protein expressions of Occludin were markedly lower in group C than in A and D (P<0.01 and P<0.05), with statistically significant differences among the four groups (F = 6.86 and 6.87, P<0.01). CONCLUSIONS: TGF-ß1 can promote the proliferation of Sertoli cells in rats and act on the tight junction of the cells by regulating the expression of Occludin.

[Effects of methyl jasmonate on accumulation of furanocoumarins in Changium smyrnioides and its suspension cells].

Changium smyrnioides is an endangered and endemic medicinal herb in China which contains rich furanocoumarins. Bergaptol, bergapten and xanthotoxin are natural furanocoumarins in Ch. smyrnioides, among which bergaptol is mainly contained in in vitro cultures while the latter ones distribute in all organs and cultures of the plant. In this study, methyl jasmonate was used to elicit furanocoumarins in both cultivated plant and suspension cells. The accumulations of biomass and 3 furanocoumarins as well as the activity of cell, phenylalanine ammonia-lyase and antioxidase were detected. The results showed that methyl jasmonate induced the biosynthesis of furanocoumarins markedly and suspension cells from petiole produced more furanocoumarins than those from leaf. In the case of suspension cells, the concentration at 100 µmol•L⁻¹ triggered the highest yield of furanocoumarins and the 10th day of the culture period was the proper time for treatment. After 4 days the yields of bergaptol, bergapten and xanthotoxin in suspension cells from petiole were enhanced to 2.83,14.04,0.62 mg•L⁻¹ respectively. The biomass and viability of treated suspension cells decreased. At the same time, the activity of antioxidase increased, which indicated that methyl jasmonate induced cell defense. In both in vivo and in vitro conditions, cells from petiole seemed to be more sensitive to methyl jasmonate treatment compared to those from leaf. Bergaptol and xanthotoxin mainly accumulated in medium and cell respectively. Bergapten was detected in both cell and medium. The elicitation treatment only enormously affected the yields but did not significantly involve the distributions of 3 furanocoumarins. This is the first systematic study focusing on the elicitation effects of methyl jasmonate and a series of changes which lead to the increase of furanocoumarins in Ch. smyrnioides cell suspension cultures. Methyl jasmonate appears to be an effective elicitor in the research and further efforts should be made to reveal the mechanism in detail.

[Simultaneous determination of amino acids and nucleosides of three species in Termitomyces by UFLC-QTRAP-MS-MS].

A comprehensive analytical method based on UFLC-QTRAP-MS-MS was developed for the simultaneous determination of 15 kinds of amino acids and 12 kinds of nucleosides of three species in Termitomyces. The separation was carried out on a Waters XBridge Amide column (2.1 mm×100 mm,3.5 µm) with gradient elution of mobile phase of 0.2% formic acid in water-0.2% formic acid in acetonitrile at a flow rate of 0.6 mL•min⁻¹, and column temperature was maintained at 30 ℃. The target compounds were analyzed by the positive ion multiple reaction monitoring (MRM) mode. The principal component analysis(PCA) was made to standardized treatment for the comprehensive evaluation of different species in Termitomyces. The 15 kinds of amino acids and 12 kinds of nucleosides multiple constituents showed good linearity (r>0.997 3) in the range of the tested concentration.The average recoveries ranged from 95.14% to 105.0%,and the relative standard deviations were less than 5.0%. The comprehensive evaluation index obtained with PCA showed that the Termitomyces albuminosus was significantly higher than others in amino acids and in nucleosides, of which the T. aurantiacus was the best. The developed method with good repeatability and accuracy was suitable for the simultaneous determination of multiple functional substances,which provided a new basis for the comprehensive assessment and overall control of the quality of Termitomyces fungi.

Excessive Exoergicity Reduces Singlet Exciton Fission Efficiency of Heteroacenes in Solutions.

The energy difference between a singlet exciton and twice of a triplet exciton, ΔESF, provides the thermodynamic driving force for singlet exciton fission (SF). This work reports a systematic investigation on the effect of ΔESF on SF efficiency of five heteroacenes in their solutions. The low-temperature, near-infrared phosphorescence spectra gave the energy levels of the triplet excitons, allowing us to identify the values of ΔESF, which are -0.58, -0.34, -0.31, -0.32, and -0.34 eV for the thiophene, benzene, pyridine, and two tetrafluorobenzene terminated molecules, respectively. Corresponding SF efficiencies of the five heteroacenes in 0.02 M solutions were determined via femtosecond transient absorption spectroscopy to be 117%, 124%, 140%, 132%, and 135%, respectively. This result reveals that higher ΔESF is not, as commonly expected, always beneficial for higher SF efficiency in solution phase. On the contrary, excessive exoergicity results in reduction of SF efficiency in the heteroacenes due to the promotion of other competitive exciton relaxation pathways. Therefore, it is important to optimize thermodynamic driving force when designing organic materials for high SF efficiency.

[Xanthones from Rhizoma of Securidaca inappendiculata].

Objective: To study the chemical constituents of Securidaca inappendiculata. Methods: The chemical constituents were isolated and purified by chromatography on silica gel, Sephadex LH-20 columns. Their structures were elucidated by means of physicochemical properties and spectroscopic analysis. Results: Ten compounds were identified from the dichloromethane fraction of Securidaca inappendiculata, and identified as 1,7-dihydroxyxanthone (1), 1,3,8-trihydroxy-2-methoxyxanthone (2), 1,7-dihydroxy-3,4-dimethoxyxanthone (3), 1,3,8-trihydroxy-4-methoxyxanthone (4), 7-hydroxy-1,2-dimethoxyxanthone (5), 1,3,6-trihydroxy-2,7-dimethoxyxanthone (6), 1,4, 8-trihydroxyxanthone (7), 1,7-dihydroxy-3-methoxyxanthone (8), 1,6-dihydroxy-7-methoxyxanthone (9) and 1,8-dihydroxy-3,4-dimethoxyxanthone (10). Conclusion: Compounds 7­10 are isolated from this plant for the first time, and compounds 7­10 are isolated from this genus for the first time.

[Structure activity relationship of annonaceous acetogenins against multidrug resistant human lung cancer cell line A549/Taxol in vitro].

10 kinds of annonaceous acetogenins were selected for antitumor activity testing against human lung cancer cell line A549/Taxol and the structure activity relationship was analyzed.MTT assay was used to detect the inhibitory activities of 10 kinds of annonaceous acetogenins and positive drugs against A549/Taxol cells, respectively uvariamicin-Ⅲ(1), uvariamicin-Ⅱ(2), annosquacin D(3), desacetyluvaricin(4), annosquatin A(5), squamostatin D(6), bullatacin(7), squamocin(8), motrilin(9), annosquatin B(10), verapamil and cisplatin. Annonaceous acetogenins showed significant inhibitory activities against A549/Taxol cells, and were more potent than the positive drug verapamil and cisplatin.The more carbon atoms between the tetrahydrofuran ring and the lactone ring of annonaceous acetogenins exhibited more potency.Besides,ACGs with two substituted hydroxyl showed more potency than the compounds with three substituted hydroxyl in the bis-adjacent-THF ACGs. Furthermore, ACGs with three substituted hydroxyl showed more potency than the compounds with four substituted hydroxyl among the no bis-adjacent-THF ACGs.

Anticancer agent-based marine natural products and related compounds.

Marine natural products constitute a huge reservoir of anticancer agents. Consequently during the past decades, several marine anticancer compounds have been isolated, identified, and approved for anticancer treatment or are under trials. In this article the sources, structure, bioactivities, mode of actions, and analogs of some promising marine and derived anticancer compounds have been discussed.

[Type of sperm DNA strand breaks in infertile men and its clinical implication].

OBJECTIVE: To observe the characteristics of sperm single-stranded DNA breaks (SSB) and double-stranded DNA breaks (DSB) in infertile men, explore the association of DSB with male infertility, and provide a new observation index and idea for the diagnosis and treatment of the disease. METHODS: This study involved 60 infertile men (infertility group) and 30 normal healthy males with infertile wives (control group). We comparatively analyzed the seminal parameters of the two groups, determined sperm concentration and viability using the computer aided sperm analysis system, measured the sperm survival rate by hypoosmotic swelling (HOS) test, examined sperm morphology by Diff-Quick staining, and detected sperm DNA damage by two-tail comet assay. RESULTS: Nine two-tail comet models were established for detecting sperm DNA integrity. Comparisons between the fertility and control groups showed that the sperm DNA fragmentation index (DFI) was (33.8 ± 13.1) vs (16.3 ± 7.9)% (P < 0.01), the SSB-DFI was (19.2 ± 11.4) vs (14.9 ± 7.6)% (P > 0.05), the SSB-DFI/DFI was (56.8 ± 32.4) vs (91.4 ± 27.8)% (P < 0.01), the DSB-DFI was (23.9 +13.4) vs (6.1 ± 2.7)% (P < 0.01), and the DSB-DFI/DFI was (70.8 ± 19.5) vs (37.4 ± 11.3)% (P < 0.01). The optimal cut-off value of DSB-DFI/DFI in the diagnosis of male infertility was 39.5%, with the AUG, sensitivity, and specificity of 0.969, 98.3%, and 90%; that of DSB-DFI was 15.85%, with the AUC, sensitivity, and specificity of 0.912, 86.7%, and 80%; and that of DFI was 18.65%; with the AUC, sensitivity, and specificity of 0.861, 90%, 70%, respectively. In the infertile men, neither SSB-DFI nor SSB-DFI/DFI exhibited any correlation with semen parameters (P > 0.05); DFI was correlated negatively with the percentage of progressively motile sperm, sperm survival rate, and the percentage of morphologically normal sperm (P < 0.05 or P < 0.01), but not correlated with sperm concentration (P > 0.05); both DSB-DFI and DSB-DFI/DFI showed a negative correlation with sperm concentration, sperm survival rate, and the percentages of progressively motile sperm and morphologically normal sperm (P < 0.05 or P < 0.01). CONCLUSION: Double-stranded, rather than single-stranded DNA breaks, may be a factor inducing male infertility. The type of sperm DNA strand damage is of much reference value for the assessment of male fertility.

[Effects of Browning Inhibitors on Suspension Cells Growth and Secondary Metabolites Production in Changium smyrnioides].

OBJECTIVE: To study the effects of browning inhibitors on Changium smyrnioides suspension cells growth and secondary metabolites production. METHODS: Different concentrations of V(C), AC, AHC, Na2S2O3 and PVP were added to the light brown suspension cells, and the contents of phenols, total coumarins, bergaptol and bergapten were determined by UV-Vis and HPLC. RESULTS: PVP with low concentration and V(C) improved the growth of the suspension cells in different degrees. It was showed that the content of phenols in the suspension cells was related to the kinds of browning inhibitors. The addition of V(C) in the medium increased the content of total coumarins significantly. After using 2 mg/mL of V(C), the gross increase rate of total coumarins was 51.53%, which was 4.8 times than that of the control group. The browning phenomenon caused by salicylic acid were inhibited by adding 2 mg/mL of V(C) into suspension culture system (with salicylic acid as the inducer). At the same time, the content of bergaptol and bergapten was increased 25.96% and 33.33%, respectively. CONCLUSION: V(C) is the best anti-browning agent in this study. It can inhibit browning, and promote cell growth and accumulation of secondary metabolites in Changium smyrnioides suspension cells.