Identification of Surface Water Quality along the Coast of Sanya,South China Sea

Principal component analysis (PCA) and cluster analysis (CA) are utilized to identify the effects caused by human activities on water quality along the coast of Sanya, South China Sea. PCA and CA identify the seasonality of water quality (dry and wet seasons) and polluted status (polluted area). The seasonality of water quality is related to climate change and Southeast monsoons. Spatial pattern is mainly related to anthropogenic activities (especially land input of pollutions). PCA reveals the characteristics underlying the generation of coastal water quality. The temporal and spatial variation of the trophic status along the coast of Sanya is governed by hydrodynamics and human activities. The results provide a novel typological understanding of seasonal trophic status in a shallow, tropical, open marine bay.     

Assessment of the modulating effects of fructo-oligosaccharides on fecal microbiota using human flora–associated piglets

We first used human flora–associated (HFA) piglets, a significantly improved model for research on human gut microbiota, to study the effects of short-chain fructo-oligosaccharides (scFOS) on the gut bacterial populations. Ten neonatal HFA piglets were assigned to receive basal diets alone or supplemented with scFOS (0.5 g/kg body weight/day) from 1 to 37 days after birth (DAB). The impact of scFOS on the fecal bacterial populations of the piglets before (12 DAB), during (17 DAB), and after (25 and 37 DAB) weaning were monitored by PCR-denaturing gradient gel electrophoresis and real-time quantitative PCR. The Bifidobacterium genus was stimulated consistently, except during weaning, confirming the bifidogenic property of scFOS. At 12 DAB, the Clostridium leptum subgroup was decreased and two unknown Bacteroides-related species were increased; at 25 DAB, the C. leptum subgroup and Subdoligranulum variabile-like species were elevated, whereas one unknown Faecalibacterium-related species was suppressed; and at 37 DAB, the Bacteroides genus was decreased. The results showed that effects of scFOS on non-bifidobacteria varied at different developmental stages of the animals, warranting further investigation into the host-development-related effects of prebiotics on the gut microbiota and the host physiology using the HFA piglets as a model for humans.     

A nuclear ligand MRG15 involved in the proapoptotic activity of medicinal fungal galectin AAL (Agrocybe aegerita lectin)

Background

We have previously reported a novel fungal galectin Agrocybe aegerita lectin (AAL) with apoptosis-induced activity and nuclear migration activity. The importance of nuclear localization for AAL's apoptosis-induced activity has been established by mutant study. However, the mechanism remains unclear.

Methods

We further investigated the mechanism using a previously reported carbohydrate recognition domain (CRD) mutant protein H59Q, which retained its nuclear localization activity but lost most of its apoptotic activity. The cell membrane-binding ability of recombinant AAL (rAAL) and H59Q was analyzed by FACS, and their cellular partners were identified by affinity chromatography and mass spectroscopy. Furthermore, the interaction of AAL and ligand was proved by mammalian two-hybrid and pull down assays. A knockdown assay was used to confirm the role of the ligand.

Results

The apoptotic activity of AAL could be blocked by lactose. Mutant H59Q retained comparable cell membrane-binding ability to rAAL. Four cellular binding partners of AAL in HeLa cells were identified: glucose-regulated protein 78 (GRP78); mortality factor 4-like protein 1 (MRG15); elongation factor 2 (EEF2); and heat shock protein 70 (Hsp70). CRD region of AAL was required for the interaction between AAL/mutant AAL and MRG15. MRG15 knockdown increased the cells' resistance to AAL treatment.

Conclusion

MRG15 was a nuclear ligand for AAL in HeLa cells. These data implied the existence of a novel nuclear pathway for the antitumor activity of fungal galectin AAL.

General significance

These findings provide a novel explanation of AAL bioactivity and contribute to the understanding of mushroom lectins' antitumor activity.     

Effect of chitosan‐alginate nanoparticles and ultrasound on the efficiency of gene transfection of human cancer cells

Background

Gene therapy has been used to treat a variety of health problems, but transfection inefficiency and the lack of safe vectors have limited clinical progress. Fabrication of a vector that is safe and has high transfection efficiency is crucial for the development of successful gene therapy. The present study aimed to synthesize chitosan‐alginate nanoparticles that can be used as carriers of the pAcGFP1‐C1 plasmid and to use these nanoparticles with an ultrasound protocol to achieve high efficiency gene transfection.

Methods

Chitosan was complexed with alginate and the pAcGFP1‐C1 plasmid at different charge ratios to create chitosan‐alginate‐DNA nanoparticles (CADNs). The average particle size and loading efficiency were measured. Plasmid DNA retardation and integrity were analysed on 1% agarose gels. The effect of CADNs and ultrasound on the efficiency of transfection of cells and subcutaneous tumors was evaluated.

Results

In the CADNs, the average size of incorporated plasmid DNA was 600–650 nm and the loading efficiency was greater than 90%. On the basis of the results of the plasmid DNA protection test, CADNs could protect the transgene from DNase I degradation. The transgene product expression could be enhanced efficiently if cells or tumor tissues were first given CADNs and then treated with ultrasound.

Conclusions

The use of CADNs combined with an ultrasound regimen is a promising method for safe and effective gene therapy. Copyright © 2009 John Wiley & Sons, Ltd.

     

Early lesions induced in rat colon epithelium by N-methyl-N′-nitro-N-nitrosoguanidine

The development of ACF (aberrant crypt foci), adenoma and cancer following intrarectal administration of the alkylating agent N-methyl-N′-nitro-N-nitrosoguanidine (MNNG) has been described. However, microscopic lesions not previously reported were observed as soon as two weeks following carcinogen treatment. These lesions protrude slightly over the epithelial lining of the colon, with a micropolyp-like appearance. Oriented sections show that the centre of these lesions present pseudo-“cystic” appearance, with disorganized crypts made of normal cells. The chorion of the lesion is invaded by numerous inflammatory cells and some ACF may be present nearby. The epithelium lining the cysts and the distorted crypts shows expression of gastric mucin M1/MUC5AC, an early marker of colonic carcinogenesis which is not present in normal colon. This mucin is retained within the “cysts” together with some inflammatory cells.The micropolyps observed contain in a minute form some histological elements described in ulcerative colitis or short-term radiotherapy (distortion of crypts, crypt abscesses, increase of chorion cellularity, infiltration by immune cells). In addition, the presence of bifid crypts nearby suggests mucosal regeneration.Our hypothesis is that these modifications are steps in a normal healing pathway that may in some cases degenerate into precancerous lesions and cancer.     

556例多发伤患者的急诊救治临床分析

目的探讨多发伤患者的救治策略。方法回顾分析我科2000年1月至2008年5月急诊抢救的556例多发伤患者的临床资料。结果 16例患者经抢救无效死亡,死亡率2.88%;其余患者均经紧急抢救及行必要实验室检查,病情稳定,好转率达97.12%。平均抢救时间为(1.37±1.05)h。结论强化多发伤的急诊科早期救治,树立创伤急救"黄金1 h"观念,是提高多发伤患者生存率及降低死亡率的关键。     

Chemical activation of parthenogenetic and nuclear transfer porcine oocytes using ionomycin and strontium chloride

Effective protocols for oocyte activation are crucial for study of parthenogenetic development and to produce nuclear transfer reconstructed embryos. This study investigated the use of ionomycin (ION) and strontium chloride (Sr(2+)) in the activation of parthenogenetic and nuclear transfer porcine oocytes. In-vitro-matured oocytes with a polar body were treated with varying concentrations of ION, Sr(2+) or its combinations, and then fixed or cultured to assess activation and development rates, respectively. Ionomycin concentrations of 10 and 15 microM resulted in more frequent oocyte activation and the 15 microM in advanced development compared to 5 microM (71.8 and 70%vs. 47.5%; P=0.04, and 43.7%vs. 19.3%; P=0.008, respectively). Oocytes treated with 10, 20 or 30 mM of Sr(2+) for 2 or 4h displayed a pronuclear formation rate ranging from 46.7 to 70%. When employed after a 5 min treatment with 10 or 15 microM ION, exposure to 10 mM Sr(2+) for 4 h resulted in higher pronuclear formation than did the 20 mM concentration (82 and 88.6%vs. 63.3 and 73.2%; P=0.03). Nuclear transfer reconstructed oocytes treated with 15 microM/5 min ION followed by 10 mM/4 h Sr(2+) resulted in a higher development to blastocyst stage compared to those treated with 15 microM ION alone (17.7 vs. 11.3%; P=0.06). In conclusion, we inferred that the inclusion of Sr(2+) in the activation protocol can benefit the development of nuclear transfer reconstructed porcine oocytes.     

Salt tolerance requires cortical microtubule reorganization in Arabidopsis

Although the results of some studies indicate that salt stress affects the organization of microtubules, it remains an open question whether microtubules play an active role in the plant's ability to withstand salt stress. In the present study, we showed that salt stress-induced wild-type Arabidopsis seedling roots display right-handed skewed growth and depolymerization of the cortical microtubules. The results of a long-term observational study showed that cortical microtubules depolymerized then reorganized themselves under salt stress. Stabilization of microtubules with paclitaxel resulted in more seedling death under salt stress, while disruption of microtubules with oryzalin or propyzamide rescued seedlings from death. Seedlings in which the cortical microtubules were reorganized did not succumb to salt stress. These results suggest that both depolymerization and reorganization of the cortical microtubules are important for the plant's ability to withstand salt stress. Depolymerizing microtubules by drugs rescues seedlings from death under salt stress. This rescue effect was abolished by removing calcium from the medium or treatment with a calcium channel inhibitor. Depolymerization of the microtubules is followed by an increase in the free cytoplasmic calcium concentration. The addition of calcium to the growth medium increased the number of seedlings in which recovery of the cortical microtubules occurred, whereas the removal of calcium decreased the number of seedlings in which recovery occurred. Therefore, depolymerization of the cortical microtubules raises intracellular calcium concentrations, while reorganization of the cortical microtubules and seedling survival may be mediated by calcium influx in salt stress.     

Developmental steps in acquiring competence for shoot development in <Emphasis Type="Italic">Arabidopsis</Emphasis> tissue culture

Arabidopsis shoots regenerate from root explants in tissue culture through a two-step process requiring preincubation on an auxin-rich callus induction medium (CIM) followed by incubation on a cytokinin-rich shoot induction medium (SIM). During CIM preincubation, root explants acquire competence to respond to shoot induction signals. During CIM preincubation, pericycle cells in root explants undergo cell divisions and dedifferentiate, losing the expression of a pericycle cell-specific marker. These cells acquire competence to form green callus only after one day CIM preincubation and to form shoots after 2–3 days CIM preincubation. Reversible DNA synthesis inhibitors interfered with the acquisition of competence to form shoots. Genes requiring CIM preincubation for upregulation on SIM were identified by microarray analysis and included RESPONSE REGULATOR 15 (ARR15), POLYGALACTURONASE INHIBITING PROTEIN 2 (PGIP2) and WUSCHEL (WUS). These genes served as developmental markers for the acquisition of competence because the CIM preincubation requirements for ARR15 and PGIP2 upregulation correlated well with the acquisition of competence to form green callus, and the CIM preincubation requirements for WUS upregulation matched those for shoot formation. Unlike ARR15, another cytokinin inducible, A-type ARR gene, ARR5, was upregulated on SIM, but the induction did not require CIM preincubation. These findings indicate that competencies for various events associated with shoot regeneration are acquired progressively during CIM preincubation, and that a set of genes, normally upregulated on SIM, are repressed by a process that can be relieved by CIM preincubation.