DNA strand-scission by phloroglucinols and lignans from heartwood of Garcinia subelliptica Merr. and Justicia plants

Five 2,4,6-prenylated phloroglucinols, garcinielliptones HA (1), HB (2), HC (3), HD (4) and HE (5), were isolated from the heartwood of Garcinia subelliptica Merr. Their structures, including relative configurations, were elucidated by means of spectroscopic data analysis. The ability of phloroglucinols, 1-5 and lignans, tuberculatin (8), justicidin A (9), procumbenoside A (10) and ciliatosides A (11) and B (12), isolated from Justicia ciliata and Justicia procumbens, to induce DNA-cleavage activity was examined using pBR322, a supercoiled, covalently closed circular DNA, and it was analyzed by agarose gel electrophoresis. In the presence of Cu (II), compounds 3, 8, 10 and 11 caused significant breakage of supercoiled plasmid pBR322. The products were relaxed circles with no detectable linear forms. In the Cu(II)-mediated DNA damage of 3 and selective compound 8, Cu(I) was shown not to be an essential intermediate by using the Cu(I)-specific sequestering reagent neocuproine.     

Antiinflammatory triterpenoids and steroids from Ganoderma lucidum and G. tsugae

The antiinflammatory properties of triterpenoids and steroids from both Ganoderma lucidum and Ganoderma tsugae were studied. Twelve compounds, including ergosta-7,22-dien-3beta-ol (1), ergosta-7,22-dien-3beta-yl palmitate (2), ergosta-7,22-dien-3-one (3), ergosta-7,22-dien-2beta,3alpha,9alpha-triol (4), 5alpha,8alpha-epidioxyergosta-6,22-dien-3beta-ol (5), ganoderal A (6), ganoderal B (7), ganoderic aldehyde A (8), tsugaric acid A (9), 3-oxo-5alpha-lanosta-8,24-dien-21-oic acid (10), 3alpha-acetoxy-5alpha-lanosta-8,24-dien-21-oic acid ester beta-d-glucoside (11), and tsugaric acid B (12), were assessed in vitro by determining their inhibitory effects on the chemical mediators released from mast cells, neutrophils, and macrophages. Compound 10 showed a significant inhibitory effect on the release of beta-glucuronidase from rat neutrophils stimulated with formyl-Met-Leu-Phe (fMLP)/cytochalasin B (CB) whereas compound 9 significantly inhibited superoxide anion formation in fMLP/CB-stimulated rat neutrophils. Compound 10 also exhibited a potent inhibitory effect on NO production in lipopolysaccharide (LPS)/interferon-gamma (IFN-gamma)-stimulated N9 microglial cells. Moreover, compound 9 was also able to protect human keratinocytes against damage induced by ultraviolet B (UV B) light, which indicated 9 could protect keratinocytes from photodamage.     

19-Nor-2α-(3-hydroxypropyl)-1α,25-dihydroxyvitamin D3 (MART-10) is a potent cell growth regulator with enhanced chemotherapeutic potency in liver cancer cells

The discovery that the active form of vitamin D, 1α,25-dihydroxyvitamin D [1α,25(OH)₂D] can modulate cellular proliferation and differentiation of cancer cells has led to its potential application as a chemotherapeutic agent to treat a variety of cancers. However, the use of 1α,25(OH)₂D is limited due to its lethal side effect of hypercalcemia upon systemic administration. To overcome this drawback, numerous analogs have been synthesized. In this report, we examined the anti-proliferative activity of a new analog, 19-nor-2α-(3-hydroxypropyl)-1α,25(OH)₂D₃ (MART-10), in HepG2 liver cancer cells, and studied the potential mechanisms mediating this action. We found that MART-10 exhibited approximately 100-fold greater activity than 1α,25(OH)₂D₃ in inhibiting HepG2 cell proliferation as determined by cell number counting method. MART-10 was also approximately 100-fold more potent than 1α,25(OH)₂D₃ in the upregulation of p21 and p27, that in turn arrested HepG2 cells at the G₀/G₁ phase to a greater extent. Given that no active caspase 3 was detected and treatment with 1α,25(OH)₂D₃ or MART-10 did not further increase the fractions of apoptotic and necrosis cells over the controls, the growth-inhibitory effect of 1α,25(OH)₂D₃ and MART-10 on HepG2 cells may not involve apoptosis. Overall, our findings suggest that MART-10 is a good candidate as a novel therapeutic regimen against liver cancer. Further pre-clinical studies using animal models and the subsequent human clinical trials are warranted.     

Rapid characterization of sugar-binding specificity by in-solution proximity binding with photosensitizers

Cell-surface carbohydrates are known to participate in many important physiological and pathological activities by interacting with their corresponding proteins or receptors. Although several methods have been developed for studying carbohydrate-protein interactions, one major problem originates from the weak bindings of carbohydrates/proteins that are often lost during repeating wash steps. Herein, we established a homogeneous solution carbohydrate array in which polyacrylamide-based glycans are used for offering a multivalent environment. The method requires no wash step and can be carried out in a high-throughput manner. We characterized the carbohydrate-binding specificities of 11 lectins and 7 antibodies, the majority of which displayed the binding patterns in consistence with previous reports. These results demonstrate that our developed solution carbohydrate array provides a useful alternative that is better than or comparable with the current available methods.     

MetaMirClust: Discovery of miRNA cluster patterns using a data-mining approach

Recent genome-wide surveys on ncRNA have revealed that a substantial fraction of miRNA genes is likely to form clusters. However, the evolutionary and biological function implications of clustered miRNAs are still elusive. After identifying clustered miRNA genes under different maximum inter-miRNA distances (MIDs), this study intended to reveal evolution conservation patterns among these clustered miRNA genes in metazoan species using a computation algorithm. As examples, a total of 15-35% of known and predicted miRNA genes in nine selected species constitute clusters under the MIDs ranging from 1kb to 50kb. Intriguingly, 33 out of 37 metazoan miRNA clusters in 56 metazoan genomes are co-conserved with their up/down-stream adjacent protein-coding genes. Meanwhile, a co-expression pattern of miR-1 and miR-133a in the mir-133-1 cluster has been experimentally demonstrated. Therefore, the MetaMirClust database provides a useful bioinformatic resource for biologists to facilitate the advanced interrogations on the composition of miRNA clusters and their evolution patterns.     

Clinicodemographic aspect of resectable pancreatic cancer and prognostic factors for resectable cancer

ABSTRACT: BACKGROUND: Pancreatic adenocarcinoma (PCA) is one of the most lethal human malignancies, and radical surgery remains the cornerstone of treatment. After resection, the overall 5-year survival rate is only 10% to 29%. At the time of presentation, however, about 40% of patients generally have distant metastases and another 40% are usually diagnosed with locally advanced cancers. The remaining 20% of patients are indicated for surgery on the basis of the results of preoperative imaging studies; however, about half of these patients are found to be unsuitable for resection during surgical exploration. In the current study, we aimed to determine the clinicopathological characteristics that predict the resectability of PCA and to conduct a prognostic analysis of PCA after resection to identify favorable survival factors. METHODS: We retrospectively reviewed the medical files of 688 patients (422 men and 266 women) who had undergone surgery for histopathologically proven PCA in the Department of Surgery at Chang Gung Memorial Hospital in Taiwan from 1981 to 2006. We compared the clinical characteristics of patients who underwent resection and patients who did not undergo resection in order to identify the predictive factors for successful resectability of PCA, and we conducted prognostic analysis for PCA after resection. RESULTS: A carbohydrate antigen 19-9 (CA 19-9) level of 37 U/ml or greater and a tumor size of 3 cm or more independently predicted resectability of PCA. In terms of survival after resection, PCA patients with better nutritional status (measured as having an albumin level greater than 3.5 g/dl), radical resection, early tumor stage and better-differentiated tumors were associated with favorable survival. CONCLUSIONS: Besides traditional imaging studies, preoperative CA 19-9 levels and tumor size can also be used to determine the resectability of PCA. Better nutritional status, curative resection, early tumor stage and well-differentiated tumors predict the favorable prognosis of PCA patients after resection.     

Anti-inflammatory flavonoids and pterocarpanoid from Crotalaria pallida and C. assamica

One new isoflavone, 5,7,4'-trihydroxy-2'-methoxyisoflavone (3) and seven, and four known compounds were isolated from the barks of Crotalaria pallida and the seeds of C. assamica, respectively. The known compounds, apigenin (1) and 2'-hydroxygenistein (2), isolated from C. pallida, showed significant concentration-dependent inhibitory effects on the release of beta-glucuronidase and lysozyme from rat neutrophils in response to formyl-Met-Leu-Phe/cytochalasin B (fMLP/CB) with IC(50) values of 2.8+/-0.1 and 17.7+/-1.9, and 5.9+/-1.4 and 9.7+/-3.5 microM, respectively. The known compounds, daidzein (4) and 2'-hydroxydaidzein (6), isolated from C. pallida, inhibited of the release of lysozyme and beta-glucuronidase from rat neutrophils in response to fMLP/CB with IC(50) values of 26.3+/-5.5 and 13.7+/-2.6 microM, respectively. Compounds 1 and 4 also showed significant concentration-dependent inhibitory effects on superoxide anion generation in rat neutrophils stimulated with fMLP/CB with IC(50) values of 3.4+/-0.3 and 25.1+/-5.0 microM, respectively. Compounds 1 and 5, previously isolated from C. pallida, showed the inhibition of NO production in lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophages and LPS/interferon-gamma (IFN-gamma)-stimulated N9 microglial cells with IC(50) values of 10.7+/-0.1 and 13.9+/-1.1 microM, respectively. Flavonoids, suppressed chemical mediators in inflammatory cells, may have value in treatment and prevention of central and peripheral inflammatory diseases associated with excess production of chemical mediators.     

DNA loop repair by Escherichia coli cell extracts

The nick-directed DNA repair efficiency of a set of M13mp18-derived heteroduplexes containing 8-, 12-, 16-, 22-, 27-, 45-, and 429-nucleotide loops was determined by in vitro assay. Unpaired nucleotides of each heteroduplex reside within overlapping recognition sites for two restriction endonucleases, permitting independent evaluation of repair occurring on either DNA strand. Our results show that a strand break located either 3' or 5' to the loop is sufficient to direct heterology repair to the nicked strand in Escherichia coli extracts. Strand-specific repair by this system requires Mg2+ and the four dNTPs and is equally efficient on insertions and deletions. This activity is distinct from the MutHLS mismatch repair pathway. Strand specificity and repair efficiency are largely independent of the GATC methylation state of the DNA and presence of the products of mismatch repair genes mutH, mutL, and mutS. This study provides evidence for a loop repair pathway in E. coli that is distinct from conventional mismatch repair.     

杨树和核桃树两种寄主植物上云斑天牛产卵刻槽的分布

为了对比杨树和核桃树两种寄主植物上云斑天牛成虫产卵方式的差异,本研究于2013年通过林间定期调查的方法得到了云斑天牛成虫在两种寄主植物上的产卵规律。杨树上,产卵刻槽沿树干一周,卵产于韧皮部或者木质部;核桃树上,产卵刻槽沿着树干上下排列,卵产于树皮缝内。两种寄主植物上,产卵刻槽的数量均随着树干高度的增高而减少,但在不同高度范围内没有差异(df=2,6,F=0.866;df=2,15,F=0.071),且在不同方向上也没有差异(F1=0.691;F2=0.646;F3=0.994)。另外还调查了寄主植物胸径与产卵刻槽数量之间的关系,结果表明,产卵刻槽不会随着寄主植物胸径的增大而增多。这些研究结论为进一步完善云斑天牛的生物学特性提供了理论依据。