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Developers often rely on API documentation to learn API directives, i.e., constraints and guidelines related to API usage. Failing to follow API directives may cause defects or improper implementations. Since there are no industry-wide standards on how to document API directives, they take many forms and are often hard to understand by developers or challenging to parse with tools. In this paper, we propose a learning based approach for extracting first-order logic representations of API directives (FOL directives for short). The approach, called LEADFOL, uses a joint learning method to extract atomic formulas by identifying the predicates and arguments involved in directive sentences, and recognizes the logical relations between atomic formulas, by parsing the sentence structures. It then parses the arguments and uses a learning based method to link API references to their corresponding API elements. Finally, it groups the formulas of the same class or method together and transforms them into conjunctive normal form. Our evaluation shows that LEADFOL can accurately extract more FOL directives than a state-of-the-art approach and that the extracted FOL directives are useful in supporting code reviews.

A domain glossary that organizes domain-specific concepts and their aliases and relations is essential for knowledge acquisition and software development. Existing approaches use linguistic heuristics or term-frequency-based statistics to identify domain specific terms from software documentation, and thus the accuracy is often low. In this paper, we propose a learning-based approach for automatic construction of domain glossary from source code and software documentation. The approach uses a set of high-quality seed terms identified from code identifiers and natural language concept definitions to train a domain-specific prediction model to recognize glossary terms based on the lexical and semantic context of the sentences mentioning domain-specific concepts. It then merges the aliases of the same concepts to their canonical names, selects a set of explanation sentences for each concept, and identifies "is a", "has a", and "related to" relations between the concepts. We apply our approach to deep learning domain and Hadoop domain and harvest 5,382 and 2,069 concepts together with 16,962 and 6,815 relations respectively. Our evaluation validates the accuracy of the extracted domain glossary and its usefulness for the fusion and acquisition of knowledge from different documents of different projects.

Chitosan oligomers show various biological activities. However, its molecular mechanisms remain unknown in LPS-stimulated macrophages. Here, we explored the inhibitive effects of chitosan oligomers on LPS-induced IL-6/TNF-α production in macrophages. The results indicated chitosan oligomers pretreatment effectively inhibited LPS-induced over-expression of both inflammatory cytokines. Signal transduction studies show chitosan oligomers may repress not only the phosphorylation of p38, ERK1/2, JNK, phosphatidylinositol 3-kinase (PI3K) and Akt, but also the activation of nuclear factor-κB (NF-κB) and activator protein-1 (AP-1). Furthermore, both the activation of NF-κB/AP-1 and the subsequent IL-6/TNF-α over-expression in LPS-induced macrophages are inhibited by specific p38 inhibitor (SB203580), ERK1/2 inhibitor (PD98059), JNK inhibitor (SP600125) and PI3K inhibitor (LY294002). In conclusion, our investigation suggests chitosan oligomers inhibited the elevated expression of IL-6/TNF-α in LPS-induced macrophages, regulated by MAPKs and PI3K/Akt pathways dependent on NF-κB/AP-1 activation.

5-Hydroxymethylfurfural (HMF) was produced from monosaccharide (fructose and glucose), polysaccharide (inulin) and the Jerusalem artichoke juice by a simple one-pot reaction including hydrolysis and dehydration using solid acid under mild condition. Hydrated niobium pentoxide (Nb(2)O(5)·nH(2)O(2)) after pretreatment showed high catalytic activities for dehydration of mono- and polysaccharide to HMF at 433 K in water-2-butanol (2:3 v/v) biphasic system, giving high HMF yield of 89% and 54% from fructose and inulin, respectively. The HMF yield was up to 74% and 65% when inulin and Jerusalem artichoke juice were hydrolyzed by exoinulinase. The solid acid made the process environment-friendly and energy-efficient to convert carbohydrates into bio-fuels and platform chemicals.

Sepsis and its derivative syndromes are major causes of morbidity and mortality in the intensive care unit. Recently, lots of studies have shown that the progression of sepsis is attributed to redox imbalance and overproduction of proinflammatory cytokines. In previous studies, we have reported the anti-oxidative and anti-inflammatory effects of chitosan oligosaccharides in vitro. In the light of these findings, we applied the model of sepsis to mice by LPS injection to investigate whether chitosan oligosaccharides have a protective effect on LPS-induced sepsis. We found that treatment by chitosan oligosaccharides not only attenuated organ dysfunction but also improved survival rate after LPS injection. To further understand how it works, we examined several proinflammatory markers including neutrophil infiltration in organs and TNF-α and IL-1β in serum, and found that these cytokines were significantly reduced by chitosan oligosaccharide treatment. In addition to this, anti-oxidants including glutathione (GSH) and catalase (CAT) levels were depleted and malondialdehyde (MDA) levels were increased in LPS-induced sepsis, while chitosan oligosaccharides smoothed out the redox imbalance. Furthermore, we also assessed c-Jun NH(2)-terminal kinase and p38 mitogen-activated protein kinase signal activation by LPS-stimulation, and found both of them were attenuated by chitosan oligosaccharide treatment. Collectively, our data demonstrated that chitosan oligosaccharides can protect mice from the LPS challenge by virtue of anti-inflammatory effects as well as anti-oxidation properties, which might offer beneficial effects for patients with sepsis.

The zinc finger proteins Mig1 and Mig2 play important roles in glucose repression of Saccharomyces cerevisiae. To investigate whether the alleviation of glucose effect would result in an increase in aerobic succinate production, MIG1 and/or MIG2 were disrupted in a succinate dehydrogenase (SDH)-negative S. cerevisiae strain. Moreover, their impacts on physiology of the SDH-negative S. cerevisiae strain were studied under fully aerobic conditions when glucose was the sole carbon source. Our results showed that the succinate production for the SDH-negative S. cerevisiae was very low even under fully aerobic conditions. Furthermore, deletion of MIG1 and/or MIG2 did not result in an increase in succinate production in the SDH-negative S. cerevisiae strain. However, the synthesis of acetate was significantly affected by MIG1 deletion or in combination with MIG2 deletion. The acetate production for the mig1/mig2 double mutant BS2M was reduced by 69.72% compared to the parent strain B2S. In addition, the amount of ethanol produced by BS2M was slightly decreased. With the mig2 mutant BSM2, the concentrations of pyruvate and glycerol were increased by 26.23% and 15.28%, respectively, compared to the parent strain B2S.

Chitooligosaccharides (cos), with a polymerization degree of 2-8, were prepared by the enzymic hydrolysis of chitosan. the anti-angiogenic activity of cos in subcutaneous xenografts in mice has been studied for the first time. as nitric oxide (no) plays a critical role in angiogenesis, we investigated the relationship between cos and the no-mediated migration of endothelial cells. the results demonstrated that cos could suppress tumor angiogenesis and exhibit antioxidant activity by increasing the sod activity in kunming mice that were implanted with human breast cancer cells, dose-dependently. cos was able to inhibit the migration of endothelial cells induced by no. in addition, cos altered the polymerization of actin and antagonized the formation of membrane extensions that were triggered by no in endothelial cells. together, these results indicated that cos had anti-angiogenic activity in vivo and in vitro, and the inhibitory activity of cos on endothelial cell migration may be due to interference with the no signal transduction pathway. (c) 2010 elsevier ltd. all rights reserved.

Lipopolysaccharide, a potent activator of the immune system, elicits the production of pro-inflammatory mediators in immunocytes. Toll-like receptor 4 (TLR4) and myeloid differentiation factor (MD) 2 receptor complex is required for recognition and signaling of LPS. Previous study suggested water soluble chitosan decreased secretion of pro-inflammatory cytokines TNF-α and IL-6. However, no studies have provided direct target and molecular mechanism of anti-inflammatory effect of chitosan oligosaccharide on LPS-stimulated cells. In this study, we found that chitosan oligosaccharides significantly inhibited binding of LPS to TLR4/MD-2 receptor complex, thus attenuated activation of mitogen-activated protein kinases (MAPKs) and decreased nuclear translocation of nuclear factor-κB (NF-κB). Finally, chitosan oligosaccharides reduced the production of pro-inflammatory mediator, such as IL-1β and nitric oxide (NO) in LPS-stimulated RAW 264.7 cells. Therefore, chitosan oligosaccharides are potential inhibitive effector of LPS.

Oligochitosan induce plant resistance against plant virus via different signal transduction pathways. Here, the Ca2+ signaling pathway was investigated by which oligochitosan elicited defense responses to tobacco mosaic virus (TMV) in tobacco (Nicotiana tabacum cv. Huangmiaoyu nn) plants. The results showed that the multiplication and movement of TMV in tobacco plants were inhibited by oligochitosan. Oligochitosan also increased cytosolic free calcium ions and regulated the expression of calreticulin. Furthermore, the inhibitory effect on TMV and the regulation effect on calreticulin were depressed when blocking the Ca2+ signaling pathway by EGTA. These results indicated that oligochitosan induced tobacco resistance to TMV through Ca2+ signaling pathway. (C) 2010 Elsevier Ltd. All rights reserved.

This study aimed to investigate the protective effect of chitosan oligosaccharides (COS) on human umbilical vein endothelial cell (HUVEC) apoptosis induced by hydrogen peroxide (H(2)O(2)). We found that COS not only reversed the decrease of cell viability and proliferation activity, but ameliorated nuclear chromatin damage in H(2)O(2)-induced HUVECs. Additionally, COS contributed to the decrease of cytosolic Ca(2+) level, increase of mitochondrial membrane potential, up-regulation of Bcl-2 mRNA, down-regulation of Bax mRNA, reduction of cleaved caspase-3 protein, inhibition of phosphorylated p38 mitogen-activated protein kinase (MAPK) and induction of phosphorylated Akt in HUVECs. Further, H(2)O(2)-induced caspase-3 activation could be suppressed by p38 MAPK inhibitor (SB203580) and up-regulated by phosphatidylinositol-3-kinase (PI3K) inhibitor (LY294002), indicating the involvement of p38 MAPK and PI3K/Akt signaling pathways. In conclusion, the results show that COS may effectively inhibit the H(2)O(2)-induced HUVEC apoptosis. (C) 2010 Elsevier Ltd. All rights reserved.

This study aimed to investigate the inhibitive effects of chitosan oligosaccharides (COS) on tumor necrosis factor (TNF)-alpha-induced over-expression of vascular adhesion molecule-1 (VCAM-1) and intercellular adhesion molecule-1 (ICAM-1) in human umbilical vein endothelial cells (HUVECs). We found that COS effectively inhibited TNF-alpha-induced expression of VCAM-1 and ICAM-1 at the level of transcription and translation. Signal transduction studies suggested that COS blocked TNF-alpha-induced activation of NF-kappa B, degradation of I kappa B alpha, and phosphorylation of p38 MAPK and ERK1/2. A further investigation showed that the NF-kappa B activation can be partly suppressed by p38 MAPK inhibitor (58203580) and ERK1/2 inhibitor (PD98059), which also ameliorated the mRNA expression of VCAM-1 and ICAM-1 in TNF-alpha-induced HUVECs. Additionally, COS decreased U937 monocyte adhesion to HUVECs induced by TNF-alpha. Our findings suggest that COS inhibit VCAM-1 and ICAM-1 production in activated HUVECs at least partly through the blockade of p38 and ERK1/2 signaling pathways. (C) 2010 Elsevier Ltd. All rights reserved.

Four oligosaccharides (penta-, hexa-, hepta- and octa-saccharide) derived from Paris polyphylla var. yunnanensis have been synthesized efficiently using a convergent glycosylation strategy. The tobacco (Nicotiana tabacum L.) growth bioactivities of the synthesized oligosaccharides were examined, using tissue-cultured seedlings grown on solid MS medium. After 2 or 3 weeks, all four oligosaccharides had stimulated tobacco seedling growth at 1.0 ppm and the pentasaccharide showed the most significant stimulus effects. Further experiments showed that the effects of pentasaccharide on tobacco growth had an obvious concentration-dependent relationship in the range of 0.1–1.0 ppm. This stimulus effect showed some decrease when the pentasaccharide concentration was higher than 1.0 ppm. At 1.0 ppm, pentasaccharide had the most significant effects, which caused a 520% fresh weight increase of tobacco. The bioactivity of these synthesized oligosaccharides suggested that they may be good prospects for the application in the control of plant growth and development.

Oligochitosan is a potent plant defense elicitor. In this paper, a novel Brassica napus mitogen-activated protein kinase (MAPK) gene induced by oligochitosan was isolated by rapid amplification of cDNA ends technique and designated as BnOIPK (oligochitosan-induced protein kinase (OIPK)). BnOIPK, with high sequence similarity to previously reported plant MAPK genes, encodes a 373-amino acid protein and belongs to the B subgroup of plant MAPK. Bioinformatics analysis showed BnOIPK contains one phosphorylation motif (TEY) and a conserved common docking domain in its C-terminal extension. With a constitutive expression in seedling leaves, BnOIPK is further upregulated upon treatment with plant hormone jasmonic acid (JA), but did not markedly respond to salicylic acid and abscisic acid. Activation of BnOIPK transcripts induced by oligochitosan depending on nitric oxide (NO) and hydrogen peroxide (H2O2) was identified by using NO, H2O2, and their scavenger, respectively. Polyclonal antibody BOK was prepared by using a 69-kD GST-BnOIPK fusion protein which was produced from pGEX-4T-1 vector. Western-blot assays showed BnOIPK could be induced by oligochitosan and JA at a short time. All these results suggest that BnOIPK might be a key node of JA-mediated defense signaling and act on the downstream of NO and H2O2.

Chitosan oligosaccharides (COS) have been reported to have anticancer activity, immuno-enhancing effect and antimicrobial activity. However, other biological activities are unknown. Herein, we investigated the protective effects of COS against hydrogen peroxide (H(2)O(2))-induced oxidative damage on human umbilical vein endothelial cells (HUVEC, ECV304 cells). After 24h pre-incubation with COS (25-200 microg/ml), the viability loss in ECV304 cells induced by H(2)O(2) (300 microM) for 12h was markedly restored in a concentration-dependent manner as measured by MTT assay. This effect was accompanied by a marked decrease in intracellular reactive oxygen species (ROS) by measuring intensity of DCFH fluorescence. COS also exerted preventive effects on suppressing the production of lipid peroxidation such as malondialdehyde (MDA), restoring activities of endogenous antioxidants including superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px), along with the capacity of increasing levels of nitric oxide (NO) and nitric oxide synthase (NOS), as were determined by commercial regent kits. In addition, pre-incubation of COS with ECV304 cells for 24h resulted in the reduction of apoptosis and the induction of cell cycle arrest in G(1)/S+M phase as assayed quantitatively by Annexin V-fluorescein isothiocyanate (FITC) apoptosis detection kit using flow cytometry. Taken together, our findings suggest that COS can effectively protect HUVECs against oxidative stress by H(2)O(2), which might be of importance in the treatment of cardiovascular diseases.

To investigate the effects of chitosan oligosaccharides (COS) on the neutrophils from glycogen-induced peritonitis mice model, the production of superoxide and hydrogen peroxide, myeloperoxidase (MPO) release as well as apoptosis were measured. We found that 100 μg/ml COS supplementation could induce the production of superoxide and hydrogen peroxide by neutrophils, meanwhile, COS promoted the apoptosis of peritoneal neutrophils, whereas the MPO release was decreased. Furthermore, superoxide dismutase (SOD) administration could abolish the pro-apoptotic effects mediated by COS. These results demonstrated that COS exerted pro-apoptotic effects on neutrophils, and superoxide played an important role in neutrophil apoptosis caused by COS. By the use of inhibitors of PLD and PI3K respectively, administration of 1-butanol and wortamannin decreased the generation of superoxide stimulated by COS. The production of superoxide caused by COS resulted from the activation of PLD and PI3K to some extent.

Chitooligosaccharides (COS) was obtained from chitosan by depolymerization with enzyme and analyzed by HPLC and TOF-MS, and the results indicated that the polymerization degree of COS was 2–18. In order to explore the anti-angiogenic activities of COS, the effect of COS on chicken chorioallantoic membrane (CAM) angiogenesis and on proliferation, migration and tube formation of human umbilical vein endothelial cells (HUVECs) induced by human hepatoma carcinoma cells (HCC) culture fluid was measured. The results showed COS had no toxicity to normal HUVECs, but could inhibit the CAM angiogenesis and the proliferation, migration and tube formation of induced HUVECs. All of these results indicate that COS have potential anti-angiogenic activities and can counteract the stimulation of HCC-culture-fluid on endothelial cells at a certain level.

chitooligosaccharides (cos) have been shown to regulate various cellular and biological functions. however, the effect of cos on apoptosis of hepatocellular carcinoma cells remains unclear. in this study, the activity and mechanism of cos against human hepatocellular carcinoma cells (smmc-7721 cells) were investigated in vitro. the experiments showed that cos notably induced the apoptosis of smmc-7721 cells and increased the cleavage of poly(adp-ribose) polymerase. it presented a dose-dependent manner, and the apoptotic rate amounted to about 38% after treatment with 0.8 mg/ml cos for 72 h. the mrna and protein levels of bax were up-regulated by cos. these results demonstrated that cos induced apoptosis of smmc-7721 cells. the possible mechanism is that cos up-regulate pro-apoptotic protein bax, and trigger the cells a start-up of the apoptosis program. (c) 2007 elsevier ltd. all rights reserved.

The effects of chitooligosaccharides(COS) on resting and PMA-activated neutrophils were estimated. MTT assays, NO estimation and superoxide detection revealed that chitooligosaccharides at concentrations of 25, 50, 75, and 100 μg/ml increased the viability, ability to produce reactive oxygen intermediates and nitrogen intermediates of resting neutrophils. Superoxide detection, degranulation assay and adhesion assay suggested that chitooligosaccharides at concentrations from 50 to 150 μg/ml reduced PMA-induced activation of neutrophils.

Oligochitosan has a variety of biological activities. To understand its mechanism, DDRT-PCR, reverse Northern blot and quantitative relative RT-PCR were used to identify and isolate genes whose transcription were altered in cultured Nicotiana tabacum (var. Samsun NN) plants that were treated with oligochitosan. Three genes whose mRNA levels significantly changed in response to oligochitosan were isolated and identified. One gene is up-regulated, and two genes are down-regulated. These genes encode a DNAJ heat shock N-terminal domain-containing protein, a histone H1 gene and a hypothetical protein, whose function is unknown. The results suggest that the usefulness of mRNA differential display technique for the detection of plant metabolic pathways affected by oligochitosan.

Animal blood is potentially an untapped source of drugs and value-added food production. More than 400 million pigs are slaughtered each year but porcine blood is usually discarded in China. This study describes the isolation and characterization of angiotensin I-converting enzyme (ACE) inhibitory peptides derived from porcine hemoglobin. The most active hydrolysate was obtained from the peptic digestion of porcine hemoglobin. After the purification of ACE-inhibitory peptides with Sephadex LH-20 gel chromatography and reversed-phase high-performance liquid chromatography (RP-HPLC) on C(18) column, two active fractions were obtained. They were analyzed by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF/MS) and electrospray ionization tandem mass spectrometry (ESI-MS/MS). They were LGFPTTKTYFPHF and VVYPWT, corresponding to the 34-46 fragment of the alpha chain and the 34-39 fragment of the beta chain of porcine hemoglobin, with IC(50) values of 4.92 and 6.02 microM, respectively. They were the first found from porcine hemoglobin; in particular, LGFPTTKTYFPHF was a novel ACE-inhibitory peptide. In addition, the purified ACE inhibitors both competitively inhibited ACE, and maintained inhibitory activity even after incubation with gastrointestinal proteases. This suggests that these peptides might have a potential antihypertensive effect.

Animal blood is potentially an untapped source of drugs and value-added food production. More than 400 million pigs are slaughtered each year but porcine blood is usually discarded in China. In this paper, globin derived from porcine hemoglobin was digested by pepsin, then the hydrolysate was separated on Sephadex LH-20 gel filtration column and five major fractions (I, II, III, IV and V) were obtained. Biological functions of the hydrolysate and five fractions were assayed. The hydrolysate and fractions IV and V had good angiotensin-I-converting enzyme inhibitory activity, with IC50 values of 1.19, 0.67, 0.10 mg/ml, respectively. Fractions I, II, III, IV showed no significant α-glucosidase inhibitory activity, but fraction V showed appreciably stronger activity than acarbose at the same concentration. Thus, the study has shown that porcine blood can be utilized to generate high value-added products, ACE inhibitory peptides and α-glucosidase inhibitory peptides.

A Cellulomonas sp. LX newly isolated from soil samples could degrade the extracellular polysaccharide (xanthan) of Xanthomonas campestris . Such degradation was inhibited by glucose addition. Xanthan-degrading enzyme activity was found in the culture supernatant when Cellulomonas sp. LX was grown in the medium with xanthan as carbon source. The optimal pH and temperature for the xanthan-degrading reaction was 6.0 and 40 °C, respectively. The bioactivity of the xantho-oligosaccharide was examined with the soybean cotyledon bioassay and found it was an active elicitor.

An inhibitor was found in the culture fluid of Pseudomonas aeruginosa PAO1, which could inhibit the activity of the Pseudomonas autoinducer (PAI). The maximal inhibitory activity occurred in stationary phase culture sup ernatant. The PAI inhibitor did not influence the cell growth and the PAI production by P. aeruginosa PAO1 when the PAI inhibitor was added into culture medium. The induced expression of lacZ in the reporter strain Agrobacterium tumefaciens NT1 was suppressed by this PAI inhibitor, whereas inhibition could be relieved by increasing the auto inducer concentration. The quorum sensing of P. aeruginosa was inhibited presumably by inhibiting the inducing activity of Pseudomonas autoinducer but not by inhibiting the production of Pseudomonas autoinducer. It was demonstrated that the structure of the PAI inhibitor was different from that of acyl-homoserine lactones.Key words: quorum sensing, autoinducer, PAI inhibitor, Pseudomonas aeruginosa, N-acylhomoserine lactone.

The development of human cancers is a multistep complex process by which cancer cells acquire the ability to overcome the restraints imposed by the surrounding normal tissue microenvironment (7). This process is believed to be driven by the intrinsic genomic instability of cancer cells to express genes that confer selective advantages under the adverse growth conditions associated with a rapidly expanding tumor mass, such as hypoxia and a poor supply of nutrients. After reaching a critical mass, cancer cells have to find ways to promote angiogenesis in order to progress and expand during late stages of tumorigenesis (4, 5). To this end, a number of genes, such as the vascular endothelial growth factor (VEGF), have been demonstrated to play critical roles in the development of tumor vasculature (4, 5, 10). However, much more remains to be learned about the molecular nature of still unidentified players and their modes of action in promoting tumor angiogenesis. Recently, large-scale efforts have been made to determine gene expression pattern differences between various types of human cancers and their corresponding normal tissues by using the serial analysis of gene expression (SAGE) and gene array analyses (14, 33-35, 37). Indeed, significant differences in gene expression patterns have been revealed by these studies. In breast cancer, for example, such investigations have led to the application of gene array analysis in the diagnosis, prognosis, and design of rational treatment of patients according to the molecular signatures of the individual tumors (21, 22, 32, 35). In the meantime, although the alterations of oncogenes and tumor suppressor genes have shown a close association with the progression of human cancers based on their defined functions, less is known about the specific contributions of a large number of genes whose expression patterns are also significantly changed during the tumorigenic process. Particularly interesting is the observation that mesenchyme-specific genes, normally associated with osteoblasts, are highly expressed by various types of human cancers (17, 31). However, the expression of mesenchyme-specific genes has not been functionally linked to the development of specific tumor phenotypes. To address this question, we sought to determine the potential contributions of such candidate genes to specific phenotypic changes associated with the progression of late-stage tumorigenesis and identified a mesenchyme-specific gene product, periostin, as a novel angiogenic factor whose overexpression by human breast cancers leads to the significant enhancement of angiogenesis. The angiogenic activity of periostin correlated with the increased expression of the VEGF receptor Flk-1/KDR by endothelial cells through an integrin αvβ3-focal adhesion kinase (FAK)-mediated signaling pathway. These findings indicate that epithelial cell-derived tumors may gain the capabilities to generate more blood vessels, invade, and metastasize during late stages of tumorigenesis by the acquired expression of genes whose functions are normally associated only with mesenchymal cells.

Molecular mechanisms associated with tumor metastasis remain poorly understood. Here we report that acquired expression of periostin by colon cancer cells greatly promoted metastatic development of colon tumors. Periostin is overexpressed in more than 80% of human colon cancers examined with highest expression in metastatic tumors. Periostin expression dramatically enhanced metastatic growth of colon cancer by both preventing stress-induced apoptosis in the cancer cells and augmenting endothelial cell survival to promote angiogenesis. At the molecular level, periostin activated the Akt/PKB signaling pathway through the α v β 3 integrins to increase cellular survival. These data demonstrated that the survival-promoting function is crucial for periostin to promote tumor metastasis of colon cancer.

Total production of harringtonine, homoharringtonine and isoharringtonine in solid cultures of Cephalotaxus fortunei was 1.22 mg/l by periodic oscillation in temperature between 10 and 25°C every 12 h for 45 days. Production was enhanced 1.8 and 1.3-fold compared to the controls at constant temperatures of 10 or 25°C. For suspension cultures subjected to such an oscillation every 24 h for 30 days, total alkaloid production of 0.18 mg/l was achieved, a 2.0 and 1.1-fold improvement compared to the suspension culture controls, correspondingly.

Chitosan oligosaccharides (COS) have been reported to exert anti-fungal activities, antitumour activities and immuno-enhancing effects. However, the potential roles of COS in the treatment of vascular inflammations remain unknown. In the present study, we examined the effects of COS on interleukin-6 (IL-6) production in human umbilical vein endothelial cells (HUVECs) induced by lipopolysaccharide (LPS). Induction of HUVECs with LPS (100 ng/ml) increased the mRNA expression and protein secretion of IL-6 (versus the vehicle-treated group, p < 0.01), which were significantly reverted by the pre-treatment with COS (50-200 microg/ml) for 24 hr before LPS exposure (versus the LPS-treated group, p < 0.05 or 0.01). Signal transduction studies showed that the pre-treatment of HUVECs with COS (50-200 microg/ml) for 24 hr markedly inhibited the LPS-induced over-expression of phosphorylated p38 mitogen-activated protein kinase (MAPK), phosphorylated ERK1/2 and nuclear factor kappaB (NF-kappaB). Moreover, the LPS-induced NF-kappaB activation was suppressed by the specific ERK1/2 inhibitor PD98059 (30 microM) (versus the LPS-treated group, p < 0.01), but not by the specific p38 MAPK inhibitor SB203580 (25 microM). Additionally, both MAPK inhibitors markedly suppressed LPS-induced IL-6 mRNA expression in HUVECs (versus the LPS-treated group, p < 0.01). In conclusion, our results suggest that COS inhibit LPS-induced up-regulation of IL-6 in HUVECs, and this can be regulated by at least two parallel signalling pathways: one via p38 MAPK pathway independent of NF-kappaB activation and one via ERK1/2 pathway dependent on NF-kappaB activation.

Enfuvirtide (ENF), the first human immunodeficiency virus type 1 (HIV-1) fusion inhibitor approved for clinical use, acts by binding to gp41 heptad repeat 1 (HR1) and preventing its interaction with the viral HR2 region. Treatment-emergent resistance to ENF has been mapped to residues within HR1, and these mutations decrease its susceptibility to ENF and may reduce viral fitness and pathogenesis, although the mechanism for these effects is not clear. N43D, a common ENF resistance mutation, was found in in vitro assays to cause a 5-50-fold in antiviral activity. We introduced this mutation into peptide models and determined the impact of this mutation by circular dichroism and X-ray crystallography. We find that the mutation results in a decrease in the thermal stability of the six-helix bundle and causes a significant change in the HR1-HR2 interface, including a loss of HR2 helicity. These data form a mechanistic basis for the decrease in ENF sensitivity and six-helix bundle stability. The E137K polymorphism, generally present at baseline in patients who develop N43D, partially compensates for the loss of stability, and we show that these residues likely form an ion pair. These data form a framework for understanding the impact of resistance mutations on viral fitness and pathogenesis and provide a pathway for the development of novel fusion inhibitor peptides.

Oyster (Crassostrea talienwhanensis Crosse) proteins were produced from fresh oyster and subsequently digested with pepsin. The separations were performed with a Sephadex LH-20 gel filtration chromatography and a RP-HPLC. A purified peptide with sequence Val-Val-Tyr-Pro-Trp-Thr-Gln-Arg-Phe (VVYPWTQRF) was firstly isolated and characterized from oyster protein hydrolysate and its ACE inhibitory activity was determined with IC50 value of 66μmol/L in vitro. Stability study for ACE inhibitory activity showed that the isolated nonapeptide had the good heat and pH stability and strong enzyme-resistant properties against gastrointestinal proteases. Kinetic experiments demonstrated that inhibitory kinetic mechanism of this peptide was non-competitive and its Km and Ki values were calculated. The yield of this peptide from oyster proteins was 8.5%. Furthermore, the oyster protein hydrolysate (fraction II), prepared by pepsin treatment firstly exhibited antihypertensive activity when it was orally administered to spontaneously hypertensive rat (SHR) at a dose of 20mg/kg. These results demonstrated that the hydrolysate from oyster proteins prepared by pepsin treatment could serve as a source of peptides with antihypertensive activity.

Oligochitosan induces defense responses to pathogenic microbes in a wide variety of plants by acting as an elicitor. In the present study, mRNA differential display was used to investigate oligochitosan-induced transcriptional activation of defense-related genes. Accordingly, a novel Ser/Thr protein kinase gene was isolated and designated as oligochitosan-induced protein kinase (oipk). Molecular cloning showed that oipk contains six introns interrupted by seven exons. The open reading frame (ORF) of the gene is 1848 bp, which encodes a putative protein of 615 amino acids with the predicted molecular mass of 70.96 kDa and a pI of 6.32. A plant oipk antisense expression vector was constructed and transformed into tobacco by Agrobacterium tumefaciens. Decreased phenylalanine ammonia-lyase (PAL, EC 4.3.1.5) activity and decreased resistance to tobacco mosaic virus (TMV) were observed in transgenic tobacco. RT-PCR analysis revealed that oipk was expressed at high levels after oligochitosan induction in wild-type tobacco, but not in transgenic tobacco. These results indicated that oipk is involved in the signal pathway of oligochitosan-induced resistance in tobacco.

The proper pairing, recombination, and segregation of chromosomes are central to meiosis and sexual reproduction. The syn1 mutation was previously identified as a synaptic mutant in a T-DNA-tagged population of plants. SYN1 has been isolated and found to exhibit similarity to Schizosaccharomyces pombe RAD21 and RAD21-like proteins, which are required for chromosome condensation and sister chromatid cohesion during mitosis. Plants homozygous for syn1 are male and female sterile and show defects in chromosome condensation and pairing beginning at leptonema of meiosis I. Fragmentation of the chromosomes was observed at metaphase I. Alternative promoters produced two SYN1 transcripts. One transcript was expressed at low levels in most tissues, whereas the other was expressed only in prebolting buds. DNA blot analyses suggest that Arabidopsis contains a small RAD21 gene family. Consistent with the DNA blot data, a second Arabidopsis RAD21-like gene has been identified. These results suggest that different RAD21-like proteins play essential roles in chromosome condensation and pairing during both meiosis and mitosis.

A new solid acid, based on tantalum hydroxide, was used to catalyze saccharide dehydration into 5-hydroxymethylfurfural (HMF) with high catalytic activity and excellent stability in a water-2-butanol biphasic system. Furthermore, good results were also obtained from Jerusalem artichoke juice with the catalyst under the same conditions.