Stability and isomerization of complexes formed by metal ions and cytosine isomers in aqueous phase

We present a systematic study of the stability of the formation of complexes produced by four metal ions (M^+/2+) and 14 cytosine isomers (C_n). This work predicts theoretically that predominant product complexes are associated with higher-energy C₄M^+/2+ and C₅M^+/2+ rather than the most stable C₁M^+/2+. The prediction resolves successfully several experimental facts puzzling two research groups. Meanwhile, in-depth studies further reveal that direct isomerization of C₁?C₄ is almost impossible, and also that the isomerization induced by either metalation or hydration, or by a combination of the two unfavorable. It is the single water molecule locating between the H1(?N1) and O2 of the cytosine that plays the dual roles of being a bridge and an activator that consequently improves the isomerization greatly. Moreover, the cooperation of divalent metal ion and such a monohydration actually leads to an energy-free C₁←C₄ isomerization in the gas phase. Henceforth, we are able to propose schemes inhibiting the free C₁←C₄ isomerization, based purely on extended hydration at the divalent metal ion.

Mining of a streptothricin gene cluster from Streptomyces sp. TP-A0356 genome via heterologous expression

Streptothricins (STs) are used commercially to treat bacterial and fungal diseases in agriculture. Mining of the sequenced microbial genomes uncovered two cryptic ST clusters from Streptomyces sp. C and Streptomyces sp. TP-A0356. The ST cluster from S. sp. TP-A0356 was verified by successful heterologous expression in Streptomyces coelicolor M145. Two new ST analogs were produced together with streptothricin F and streptothricin D in the heterologous host. The ST cluster was further confirmed by inactivation of gene stnO, which was proposed encoding an aminomutase supplying -lysines for the poly-β-Lys chain formation. A putative biosynthetic pathway for STs is proposed based on bioinformatics analyses of the ST genes and experimental evidence.     

Feasibility and Safety of Laparoscopic Liver Resection for Hepatocellular Carcinoma with a Tumor Size of 5–10 cm

Background

Although laparoscopic liver resection has developed rapidly and gained widespread acceptance for the treatment of benign liver diseases and hepatocellular carcinoma with a small tumor size, its usefulness for the treatment of large tumors is less clear, due to concerns about compromising oncological principles and patient safety. The purpose of this study was to explore the safety and feasibility of laparoscopic liver resection for the treatment of hepatocellular carcinoma with a tumor size of 5–10 cm.

Methods

From March 2007 to December 2011, we performed liver resection in 275 patients with hepatocellular carcinoma with a tumor size of 5–10 cm. Laparoscopic liver resection was performed in 97 patients (Lap-Hx group) and open liver resection was performed in 178 patients (Open-Hx group). Operative time, estimated intraoperative blood loss, blood transfusion rate, and length of postoperative hospital stay were compared between the two groups. Early and intermediate-term postoperative outcomes were also compared.

Results

Only one liver resection was performed for every patient with HCC in the present study.No operative deaths occurred in either group. Nine of the laparoscopic procedures were converted to open resection (conversion rate 9.28%). There were no significant differences in mean operative time (245±105 min vs 225±112 min; P = .469), mean estimated intraoperative blood loss (460±426 mL vs 454±365 mL; P = .913), or blood transfusion rate (4.6%, 4/88) vs (2.8%, 5/178)(P = .480) between the Lap-Hx and Open-Hx groups. However, postoperative hospital stay was shorter in the Lap-Hx group than the Open-Hx group (8.2±3.6 days vs 13.5±3.8 days; P = .028). There was a lower rate of postoperative complications in the Lap-Hx group than the Open-Hx group (9% vs 30%; P = .001), but there were no severe complications in either group. The median overall follow-up time was 21 months (range 2–50 months) and the median follow-up of time of survivors was 23 months. The median follow-up time was 25 months in the Lap-Hx group and 20 months in the Open-Hx group. The follow-up rate was 95% (84 patients) in the Lap-Hx group and 95% (169 patients) in the Open-Hx group, which was not a significant difference between the two groups (P = .20). Tumor recurrence occurred in 17 patients (20%) in the Lap-Hx group and 35 patients (21%) in the Open-Hx group, which was not a significant difference between the two groups (P = .876). A total of 33 patients (13%) died during the study period, including 12 patients (14%) in the Lap-Hx group and 21 patients (12%) in the Open-Hx group, which was not a significant difference between the two groups (P = .695). There were also no significant differences in the 1-year rates of overall survival (94% vs 95%; P = .942) or disease-free survival (93% vs 92%; P = .941), or the 3-year rates of overall survival (86% vs 88%; P = .879) or disease-free survival (66% vs 67%; P = .931), between the Lap-Hx and Open-Hx groups.

Conclusions

Laparoscopic liver resection is safe and feasible in patients with hepatocellular carcinoma with a tumor size of 5–10 cm. Laparoscopic liver resection can avoid some of the disadvantages of open resection, and is beneficial in selected patients based on preoperative liver function, tumor size and location.     

Activation of canonical wnt pathway promotes differentiation of mouse bone marrow‐derived MSCs into type II alveolar epithelial cells,confers resistance to oxidative stress,and promotes their migration to injured lung tissue in vitro

The differentiation of mesenchymal stem cells (MSCs) into type II alveolar epithelial (AT II) cells in vivo and in vitro, is critical for reepithelization and recovery in acute lung injury (ALI), but the mechanisms responsible for differentiation are unclear. In the present study, we investigated the role of the canonical wnt pathway in the differentiation of mouse bone marrow‐derived MSCs (mMSCs) into AT II cells. Using a modified co‐culture system with murine lung epithelial‐12 (MLE‐12) cells and small airway growth media (SAGM) to efficiently drive mMSCs differentiation, we found that GSK 3β and β‐catenin in the canonical wnt pathway were up‐regulated during differentiation. The levels of surfactant protein (SP) C, SPB, and SPD, the specific markers of AT II cells, correspondingly increased in mMSCs when Wnt3a or LiCl was added to the co‐culture system to activate wnt/β‐catenin signaling. The expression of these factors was depressed to some extent by inhibiting the pathway with the addition of DKK 1. The differentiation rate of mMSCs also depends on their abilities to accumulate and survive in inflammatory tissue. Our results suggested that the activation of wnt/β‐catenin signaling promoted mMSCs migration towards ALI mouse‐derived lung tissue in a Transwell assay, and ameliorated the cell death and the reduction of Bcl‐2/Bax induced by H₂O₂, which simultaneously caused reduced GSK 3β and β‐catenin in mMSCs. These data supports a potential mechanism for the differentiation of mMSCs into AT II cells involving canonical wnt pathway activation, which may be significant to their application in ALI. J. Cell. Physiol. 228: 1270–1283, 2013. © 2012 Wiley Periodicals, Inc.     

Homeogenetic inductive mechanism of segmentation in polychaete tail regeneration

Segmentation is a body-patterning strategy in which new segments are specified from a segment-addition zone containing uncommitted cells. However, the cell-recruitment process is poorly understood. Here we investigated in detail the segmentation in a polychaete annelid, Perinereis nuntia (Lophotrochozoa), in which new segments emerge at the boundary between the posterior end of the segmented region and the terminal pygidium. Cells at this border synchronously remodel their chromatin, enter the cell cycle, and undergo oriented cell division, before being added to new segments. wingless is expressed at the posterior edge of the pre-existing segment, abutted by hedgehog in the first row of the new segment. Overstimulation of Wingless signaling caused excess cells to enter the cell cycle, prolonging segmentation and widening the new segment. Thus, segment addition may occur by a homeogenetic mechanism, in which Wingless expressed in the differentiated segment coordinates the stepwise recruitment of undifferentiated cells from the segment/pygidium boundary.     

相似相容物质对嗜冷甲烷叶菌R15的冷保护作用

摘要:嗜冷甲烷叶菌R15(Methanolobus psychrophilus R15)是本实验室分离自青藏高原若尔盖湿地的一株甲烷古菌新种。前期研究发现其生长温度范围为0℃－30℃,最适生长温度为18℃,并能在5 mmol/L至800 mmol/L NaCl中生长。【目的】鉴定甲烷古菌的相似相容物质,并探讨它们对甲烷古菌的冷保护作用和可能的作用机理。【方法】用LC-MS 分析低温下甲烷古菌胞内积累的相似相容物质;检测积累的及已知的相似相容物质对R15低温生长的促进作用,并以研究酶稳定性的模式蛋白谷氨酸脱氢酶(GDH)为对象,分析 相似相容物质对低温下酶的稳定性作用。【结果】在4℃培养和冷胁迫的R15细胞内检测到胆碱和甜菜碱的积累;发现胆碱、甜菜碱、甘氨酸、肉毒碱、乙偶姻和四氢嘧啶6 种相似相容物质促进R15的低温生长,而且胆碱、甜菜碱及甘氨酸能提高GDH 酶的低温稳定性。【结论】甲烷古菌的相似相容物质同时具有低温保护作用,本研究扩展了对相似相容物质生理功能的认识。     

Seasonal variation of diet and time budget of Eastern hoolock gibbons (Hoolock leuconedys) living in a northern montane forest

Most gibbons dwell in the tropical forests of Southeastern Asia, but eastern hoolock gibbons (Hoolock leuconedys) survive in high montane forest ranging from 1,600 to 2,700 m a.s.l. in Gaoligongshan (>24°30′N), Yunnan, China. To assess the behavioral adaptations of hoolock gibbons to the montane forest, we related temperature and food availability within the habitat to the seasonal behavioral patterns of a family group and a solitary female between August 2010 and September 2011 in Nankang, Gaoligongshan National Nature Reserve. The maximum temperature was 29.2 °C and the minimum temperature was ?0.3 °C during the period. The monthly mean temperature was <10 °C between December and February, making Nankang the coldest gibbon habitat reported so far. Nonfig fruit and fig availability declined to nearly zero in cold months. The family group increased resting and decreased travel and social behaviors when the monthly mean temperature was low. Compared with other gibbon populations, the hoolock gibbons spent proportionally less time feeding on figs and other fruit than other gibbon populations except Nomascus concolor and Symphalangus syndactylus. Only 36 species of plants provided nonfig fruit or figs, which is less than the number of fruit species consumed by any other gibbon population observed during a similar period of time (about 1 year). Hoolock gibbons shifted their diet to leaves and increased feeding time when fruit was not available. We conclude that diet flexibility and an energy-conserving strategy during the cold season when fruit is scarce have enabled the hoolock gibbons to survive in a northern montane forest.     

Cloning, expression, and characterization of TNFSF14 (LIGHT) gene in mefugu, Takifugu obscurus

Tumor necrosis factor receptor-associated factor 6 (TRAF6), which plays an important role in inflammation and immune response, is an essential adaptor protein for the NF-κB (nuclear factor κB) signaling pathway. Recent studies have shown that TRAF6 played an important role in tumorigenesis and invasion by suppressing NF-κB activation. However, up to now, the biologic role of TRAF6 in glioma has still remained unknown. To address the expression of TRAF6 in glioma cells, four glioma cell lines (U251, U-87MG, LN-18, and U373) and a non-cancerous human glial cell line SVG p12 were used to explore the protein expression of TRAF6 by Western blot. Our results indicated that TRAF6 expression was upregulated in human glioma cell lines, especially in metastatic cell lines. To investigate the role of TRAF6 in cell proliferation, apoptosis, invasion, and migration of glioma, we generated human glioma U-87MG cell lines in which TRAF6 was either overexpressed or depleted. Subsequently, the effects of TRAF6 on cell viability, cell cycle distribution, apoptosis, invasion, and migration in U-87MG cells were determined with 3-(4,5-dimethylthiazol-2-yl) 2,5-diphenyl tetrazolium bromide (MTT) assay, flow cytometry analysis, transwell invasion assay, and wound-healing assay. The results showed that knockdown of TRAF6 could decrease cell viability, suppress cell proliferation, invasion and migration, and promote cell apoptosis, whereas overexpression of TRAF6 displayed the opposite effects. In addition, the effects of TRAF6 on the expression of phosphor-NF-κB (p-p65), cyclin D1, caspase 3, and MMP-9 were also probed. Knockdown of TRAF6 could lower the expression of p-p65, cyclin D1, and MMP-9, and raise the expression of caspase 3. All these results suggested that TRAF6 might be involved in the potentiation of growth, proliferation, invasion, and migration of U-87MG cell, as well as inhibition of apoptosis of U-87MG cell by abrogating activation of NF-κB.     

Albumin domain II mutant with high bilirubin binding affinity has a great potential as serum bilirubin excretion enhancer for hyperbilirubinemia treatment

Background

4Z,15Z-bilirubin-IXα (BR), an endogenous toxic compound that is sparingly soluble in water, binds human serum albumin (HSA) with high affinity in a flexible manner. Our previous findings suggest that both Lys195 and Lys199 in subdomain IIA are important for the high-affinity binding of BR, and especially Lys199 in stand-alone domain II plays a prominent role in the renal elimination of BR. Our hypothesis is that HSA-domain II with high BR binding would be a useful therapeutic agent to treat hyperbilirubinemia in patients with impaired liver function.

Methods

Unbound BR concentrations were determined using a modified HRP assay. To evaluate the effect of pan3_3-13 domain II mutant in promoting urinary BR excretion, the serum concentration and urinary excretion amount of BR were determined using bile duct ligation mice.

Results

After three or six rounds of panning, pan3_3-13 and pan6_4 were found to have a significantly higher affinity for BR than wild-type domain II. Administration of pan3_3-13 significantly reduced serum BR level and increased its urinary excretion in the disease model mice as compared to wild-type domain II treatment.

Conclusions

These results suggest that pan3_3-13 has great potential as a therapeutic agent that promotes urinary BR excretion in hyperbilirubinemia.

General significance

This is the first study to be applied to other HSA bound toxic compounds that are responsible for the progression of disease, thereby paving the way for the development of non-invasive and cost effective blood purification treatment methods.