The promoting molecular mechanism of alphafetoprotein on the growth of human hepatoma Bel7402 cell line

AIM: The goal of this study was to characterize the AFP receptor, its possible signal transduction pathway and its proliferative functions in human hepatoma cell line Bel 7402. METHODS: Cell proliferation enhanced by AFP was detected by MTT assay, 3H-thymidine incorporation and S-stage percentage of cell cycle analysis. With radioactive labeled 125I-AFP for receptor binding assay; cAMP accumulation, protein kinase A activity were detected by radioactive immunosorbent assay and the change of intracellular free calcium (Ca2+i) was monitored by scanning fluorescence intensity under TCS-NT confocal microscope. The expression of oncogenes N- ras, p 53, and p21( ras ) in the cultured cells in vitro were detected by Northern blotting and Western blotting respectively. RESULTS: It was demonstrated that AFP enhanced the proliferation of human hepatoma Bel 7402 cell in a dose dependent fashion as shown in MTT assay, (3)H-thymidine incorporation and S-phase percentage up to 2-fold. Two subtypes of AFP receptors were identified in the cells with Kds of 1.3 x 10(-9)mol.L(-1) and 9.9 x10(-8)mol. (-1)L respectively. Pretreatment of cells with AFP resulted in a significant increase (625%) in cAMP accumulation. The activity of protein kinase A activity were increased up to 37.5, 122.6, 73.7 and 61.2% at treatment time point 2, 6, 12 and 24 hours. The level of intracellular calcium were elevated after the treatment of alpha-fetoprotein and achieved to 204% at 4 min. The results also showed that AFP(20mg.L(-1)) could upregulate the expression of N- ras oncogenes and p 53 and p21( ras ) in Bel 7402 cells. In the later case,the alteration were 81.1%(12h) and 97.3%(12h) respectively compared with control. CONCLUSION: These results demonstrate that AFP is a potential growth factor to promote the proliferation of human hepatoma Bel 7402 cells. Its growth-regulatory effects are mediated by its specific plasma membrane receptors coupled with its transmembrane signaling transduction through the pathway of cAMP-PKA and intracellular calcium to regulate the expression of oncogenes.

Geology and D-O-C Isotope Systematics of the Tieluping Silver Deposit,Henan, China: Implications for Ore Genesis

The Tieluping silver deposit, which is sited along NE-trending faults within the high-grade metamorphic basement of the Xiong'er terrane, is part of an important Mesozoic orogenic-type Ag-Pb and Au belt recently discovered. Ore formation includes three stages: Early (E), Middle (M) and Late (L), which include quartz-pyrite (E), polymetallic sulfides (M) and carbonates (L), respectively. The E-stage fluids are characterized by δD=-90‰, and δ 18 O=9‰ at 373°C, and are deeply sourced; the L-stage fluids, with δD=-70‰, and δ 18 O=-2‰, are shallow-sourced meteoric water; whereas the M-stage fluids, with δD=-109‰, and δ 18 O=2‰, are a mix of deep-sourced and shallow-sourced fluids. Comparisons of the D-O-C isotopic systematics of the E- stage ore-forming fluids with the fluids derived from Mesozoic granites, Archean-Paleoproterozoic metamorphic basement and Paleo-Mesoproterozoic Xiong'er Group, show that these units cannot generate fluids with the measured isotopic composition (highδ 18 O and δ 13 C ratios and lowδD ratios) characteristic of the ore-forming fluids. This suggests that the E-stage ore-forming fluids originated from metamorphic devolatilization of a carbonate-shale-chert lithological association, locally rich in organic matter, which could correspond to the Meso-Neoproterozoic Guandaokou and Luanchuan Groups, rather than to geologic units in the Xiong'er terrane, the lower crust and the mantle. This supports the view that the rocks of the Guandaokou and Luanchuan Groups south of the Machaoying fault might be the favorable sources. A tectonic model that combines collisional orogeny, metallogeny and hydrothermal fluid flow is proposed to explain the formation of the Tieluping silver deposit. During the Mesozoic collision between the South and North China paleocontinents, a crustal slab containing a lithological association consisting of carbonate-shale-chert, locally rich in organic matter (carbonaceous shale) was thrust northwards beneath the Xiong'er terrane along the Machaoying fault. Metamorphic devolatilization of this underthrust slab provided the ore-forming fluids to develop the Au-Ag-(Pb-Zn) ore belt, which includes the Tieluping silver deposit.

Clinical features,diagnosis,treatment and prognosis of multiple primary colorectal carcinoma

AIM: To investigate the clinical features, diagnosis,treatment and prognosis of multiple primary colorectal carcinomas (MPCC). METHODS: A retrospective analysis of 37 patients with MPCC from 1974 to 1998 was carried out.RESULTS: The incidence of MPCC was 2.74%(37/1 348) in patients with primary colorectal carcinomas, 15 cases of them were patients with synchronous carcinomas (SC) and 22 cases were diagnosed as metachronous carcinomas (MC). Most tumors were located in the right colon and rectum. Fifty-five percent (12/22) of MC were diagnosed within 3 years after tumor resection and 41%(9/22) of MC occurred after 8 years. Radical resections were performed in all patients except for 1 case. The 5-year survival rate of SC was 72.7%(8/11) and that of MC after the first cancer and second cancer was 71.4%(15/21) and 38.9%(7/18), respectively. CONCLUSION: The results indicate the importance of complete preoperative examination, careful intraoperative exploration and periodic postoperative surveillance. Early diagnosis and radical resection can increase survival rate of MPCC.

Hepatic differentiation capability of rat bone marrow-derived mesenchymal stem cells and hematopoietic stem cells

AIM: To investigate the different effects of mesenchymal stem cells (MSCs) and hematopoietic stem cells (HSCs) on hepatic differentiation.METHODS: MSCs from rat bone marrow were isolated and cultured by standard methods. HSCs from rat bone marrow were isolated and purified by magnetic activated cell sorting. Both cell subsets were induced. Morphology, RT-PCR and immunocytochemistry were used to identify the hepatic differentiation grade.RESULTS: MSCs exhibited round in shape after differentiation, instead of fibroblast-like morphology before differentiation. Albumin mRNA and protein were expressed positively in MSCs, without detection of alpha-fetoprotein (AFP). HSCs were polygonal in shape after differentiation. The expression of albumin signal decreased and AFP signal increased. The expression of CK18 was continuous in MSCs and HSCs both before and after induction.CONCLUSION: Both MSCs and HSCs have hepatic differentiation capabilities. However, their capabilities are not the same. MSCs can differentiate into mature hepatocyte-like cells, never expressing early hepatic specific genes, while Thy-1.1^+cells are incllned to differentiate into hepatic stem cell-like cells, with an increasing AFP expression and a decreasing albumin signal. CK18 mRNA is positive in Thy-1.1^+ cells and MSCs, negative in Thy-1.1^+ cells. It seems that CK18 has some relationship with Thy-1.1 antigen, and CK18 may be a predictive marker of hepatic differentiation capability.

Age, Mechanism and Direction of East Qinling-Dabieshan Lithosphere Delamination Petrological Evidence and Stipulation

Through studies of P\|T\|t paths and decompressive retrograde metamorphic textures of metamorphic rocks in the East Qinling\|Dabieshan region, the authors determined the Mesozoic crust rapid uplifting age, and then inferred that in the East Qinling\|Dabieshan region lithosphere delamination occurred from T\-3 to J\-1. The Yanshanian granites produced by delamination are developed well in the East Qinling\|Dabieshan region. But due to the Gondwana plate effect, magmatism in the region caused by delamination lagged until J\-3 when the northern Tibet terrane and the Eurasian plate completely amalgamated. Additionally, due to western Pacific plate subducting underneath the Eurasian plate, in the East Qinling\|Dabieshan region the stress state was transformed from compression to extension. So in the region from J\-3 to K\-2 magmatism was most intensive, and liberalization was also relatively strong. Geophysical data reflect that in the East Qinling\|Dabieshan region the asthenosphere rose to the shallow level, the Moho is flat with no mountain root, and the crustal thickness is less than 40 km on average. These features agree with those of collisional orogenes in which delamination has occurred. Through contrasting differences in surface and interior depth between east and west Qinling we believe that delamination proceeded from east to west.

Role of COX-2 in carcinogenesis of colorectal cancer and its relationship with tumor biological characteristics and patients' prognosis

AIM: Recent clinical epidemiological studies havedemonstrated the preventive effect of non-steroidal anti-inflammatory drugs (NSAIDs) against colorectal cancer.The underlying mechanism might be the inhibition of rate-limiting enzyme cyclooxygenase-2 (COX-2) in metabolismof arachidonic acid. The role of COX-2 in carcinogenesisof colorectal cancer and its relationship with tumorbiological characteristics and patients′ prognosis stillremain unclear. This study was to investigate the role ofCOX-2 expression in carcinogenesis of colorectal cancerand its relationship with tumor biological characteristicsand patients′ prognosis.METHODS: A total of 139 colorectal cancers and 19adenomas surgically treated in School of Oncology, PekingUniversity, from January 1993 to September 2001 wereretrospectively studied. COX-2 expression was detected withtissue microarray (TMA) and immunohistochemistry (IHC)procedure. The association between COX-2 expression andclinicopathological features and its influence on patients′prognosis were studied.RESULTS: COX-2 expression was strong in colorectal cancer,moderate in adenoma and weak in normal mucosa, whichdemonstrated statistically significant difference (x2=46.997,P＜0.001). COX-2 expression had no association withclinicopathological features such as gross type,differentiation, invasion depth, vessel emboli and TNMstaging. Cox proportional hazards modeling analysis and Logrank test revealed no prognostic role of COX-2 expressionin colorectal cancer patients.CONCLUSION: COX-2 may play an important role in theearly stage of carcinogenesis, and its expression in colorectalcancer is not associated with clinicopathological features and patients′ prognosis.

Hypoxia-inducible factor-1 in tumour angiogenesis

Hypoxia-inducible factor-1 (HIF-1), composed of HIF-α andHIF-13 subunits, is a heteroclimeric transcriptional activator.In response to hypoxia, stimulation of growth factors, andactivation of oncogenes as well as carcinogens, HIF-1α is overexpressed and/or activated and targets those geneswhich are required for angiogenesis, metabolic adaptationto low oxygen and promotes survival. HIF-1 is critical forboth physiological and pathological processes. Several dozensof putative direct HIF-1 target genes have been identifiedon the basis of one or more c/s-acting hypoxia-responseelements that contain an HIF-1 binding site. A variety ofregulators including growth factors, genetic alterations, stressactivators, and some carcinogens have been documentedfor regulation of HIF-1 in which several signaling pathwaysare involved depending on the stimuli and cell types.Activation of HIF-1 in combination with activated signalingpathways and regulators is implicated in tumour progressionand prognosis. This review presents a summary of thestructure and function of HIF-1α, and correlation amongspecific regulators and their signaling pathways.

Transabdominal ultrasonography in preoperative staging of gastric cancer

AIM: To investigate the value of transabdominal ulbasonography (US) in the preoperative staging of gastric cancer.METHODS: A total of 198 patients with gastric cancer underwent preoperatively transabdominal US, depth of tumor infiltration was assessed in 125 patients, and lymph node metastasis was assessed in 106 patients,RESULTS: The staging accuracy of transabdominal US was 55.6%, 75.0%, 87.3% and 71.1% in T1, T2, T3 and T4 carcinomas, respectively. The overall accuracy was 77.6%.The detection rate for pancreatic invasion and liver invasion was 77.4%, 71.4%, respectively. The sensitivity, specificity,accuracy of transabdominal US in assessment of lymph node metastasis were 77.6%, 64.1%, 72.6%, respectively.Various shapes such as round, ovoid, spindle were encountered in benign and malignant lymph nodes. Majority of boa benign and malignant lymph nodes were hyperechoic and had a distinct border. Benign lymph nodes were smaller than malignant lymph nodes in length and width (P = 0.000,0.005). Irregular shape, fusional shape, infiltrative signs,inhomogenous echo were seen mainly in malignant lymph nodes (P = 0.045, 0.006, 0.027, 0.006).CONCLUSION: Transabdominal US is useful for preoperative staging in gastric cancer, although it is difficult to differentiate benign from malignant lymph nodes.

Extension of the Louzidian Metamorphic Core Complex and Development of Supradetachment Basins in Southern Chifeng,Inner Mongolia,China

The Louzidian metamorphic core complex (LMCC) in southern Chifeng is located on the northern margin of the North China craton. Structural analyses of the LMCC and its extensional detachment system indicate that the LMCC experienced two-stage extension. The ductile regime experienced top-to-northeast shearing extension and the brittle detachment fault underwent top-down-outwards slipping. Between these two stages, a semi-ductile regime recorded the transition from ductile to brittle. The hanging wall of the detachment fault is similar to those classic supradetachment basins in western North America. Analyses of provenance and paleocurrent directions in the basins show that there were two filling stages. In the early stage, materials came from the southwest margin of the basin and the hanging wall of the detachment system and were transported from southwest to northeast; while in the late stage, deposits were derived from the footwall of the detachment fault and transported outwards to the two sides of the core complex. Since the filling period of the basins is from the late Jurassic to the late Cretaceous and it is coeval with the extension, the two filling stages reflect the two-stage history of the detachment fault. The large-scale late Jurassic underplating in the deep crust of the Chifeng area led to thickening and heating of the middle-upper crust and trigged the extension at depths and volcanism on the surface. In the early Cretaceous the upper plate of the detachment fault moved northeastwards and sediments were transported from southwest to northeast, while in the late Cretaceous the core complex was uplifted rapidly, the original basin was separated by the uplifted core, and lower-plate-derived debris was deposited in the adjacent upper-plate basins of the detachment fault. Evidentially, the development of the supradetachment basins were controlled by the extension and in turn the fillings in the basins recorded information of the extension, which has provided new evidence for kinematic interpretation of the Louzidian core complex.

A New Approach to Solve Nonlinear Wave Equations

From the nonlinear sine-Gordon equation, new transformations are obtained in this paper, which are applied to propose a new approach to construct exact periodic solutions to nonlinear wave equations. It is shown that more new periodic solutions can be obtained by this new approach, and more shock wave solutions or solitary wave solutions can be got under their limit conditions.

Expression of ECRG4,a novel esophageal cancer-related gene,downregulated by CpG island hypermethylation in human esophageal squamous cell carcinoma

AIM: To study the mechanisms responsible for inactivation of a novel esophageal cancer related gene 4 (ECRG4) in esophageal squamous cell carcinoma (ESCC). METHODS: A pair of primers was designed to amplify a 220 bp fragment, which contains 16 CpG sites in the core promoter region of the ECRG 4 gene. PCR products of bisulfite-modified CpG islands were analyzed by denaturing high-performance liquid chromatography (DHPLC), which were confirmed by DNA sequencing. The methylation status of ECRG 4 promoter in 20 cases of esophageal cancer and the adjacent normal tissues, 5 human tumor cell lines (esophageal cancer cell line-NEC, EC109, EC9706; gastric cancer cell line- GLC; human embryo kidney cell line-Hek293)and 2 normal esophagus tissues were detected. The expression level of the ECRG 4 gene in these samples was examined by RT-PCR. RESULTS: The expression level of ECRG 4 gene was varied.Of 20 esophageal cancer tissues, nine were unexpressed,six were lowly expressed and five were highly expressed compared with the adjacent tissues and the 2 normal esophageal epithelia. In addition, 4 out of the 5 human cell lines were also unexpressed. A high frequency of methylation was revealed in 12 (8 unexpressed and 4 lowly expressed)of the 15 (80%) downregulated cancer tissues and 3 of the 4 unexpressed cell lines. No methylation peak was observed in the two highly expressed normal esophageal epithelia and the methylation frequency was low (3/20) among the 20 cases in the highly expressed adjacent tissues. The methylation status of the samples was consistent with the result of DNA sequencing. CONCLUSION: These results indicate that the inactivation of ECRG 4gene by hypermethylation is a frequent molecular event in ESCC and may be involved in the carcinogenesis of this cancer.

Minerogenic Theory of the Superlarge Lop Nur Potash Deposit, Xinjiang, China

Located in the eastern part of the Tarim basin, Xinjiang, the Lop Nur was an ultimate water catchment area of the Tarim basin during the Quaternary. Through nearly ten years of investigation and research, the authors have found a superlarge brine potash deposit in the Luobei subbasin—a secondary basin of the Lop Nur depression. The deposit has been mined now. On that basis, the authors propose new theories on the genesis of the potash rock deposit. In the tectonic and geomorphologic contexts, the Tarim basin lies in a 'high mountain-deep basin' environment. At the beginning of the Quaternary, influenced by the neotectonic movement, the Lop Nur evolved into a 'deep basin' in the Tarim basin. At the end of the middle Pleistocene, neotectonic migration began to take place in the interior of the Lop Nur and a new secondary deep basin—the Luobei subbasin—formed gradually. Despite its small area, it is actually the deepest subbasin in the Lop Nur depression, where brines of the Lop Nur Salt Lake gather and evaporate, thus providing materials for the formation of a superlarge brine potash rock deposit. With respect to the phenomenon of brine concentration and change with deepening of the lake, the authors propose a model of 'high mountain-deep basin' tectonic migration for potash concentration. In the sedimentological context, the honeycomb-shaped voids developed in glauberite rock in the subbasin are good space for potash-rich brine accumulation. Study indicates that the deposition of glauberite requires recharge of calcium-rich water. In the Tarim area the calcium-rich water might come from deep formation water or oilfield water, and the river water recharging the Lop Nur Salt Lake was rich in sulfate radicals and other components; in addition, the climate in the area was very dry and the brine evaporated steadily, thus resulting in deposition of substantial amount of glauberite, potash accumulation in intercrystal brine and final formation of the potash deposit. Generally, potash formation in a salt lake undergoes a three-stage process of 'carbonates—?sulfates (gypsum and glauberite)—^chlorides (halite etc.)', but in the study area there only occurred a two-stage process of 'carbonates—>sulfates (gypsum and glauberite)'. The authors call this new geological phenomenon the 'two-stage potash formation' model. In conclusion, the superlarge Lop Nur potash deposit is the result of combined 'high mountain-deep basin' tectonism and 'two-stage potash formation'.

Role of nucleostemin in growth regulation of gastric cancer,liver cancer and other malignancies

AIM:To examine the role of nucleostemin in the growth regulation of gastric cancer,liver cancer and other cancers.METHODS:RT-PCR was used to clone the fragment of nucleostemin cDNA from HEK 293 cells.Eighteen kinds of malignant tumor tissues including gastric adenocarcinoma and liver cancer tissues,3 kinds of benign tumor tissues,3 kinds of benign hyperplastic tissues and normal tissues were employed to examine nucleostemin gene expression by RT-PCR,Slot blot,Northern blot and in situ hybridization.RESULTS:We successfully cloned a 570 bp fragment of nucleostemin-cDNA from HEK-293 cells.All edtected malignant tumor tissues,benign tumor tissues,and benign hyperplastic tissues had hign levels of nucleostemin expression.Nucleostemin was also expressed in human placenta tissue at a high levle.In terminally differentiated normal human adult kidney and mammary gland tissues,no nucleostemin expression could be detected.CONCLUSION:Nucleostemin can help regulate the proliferation of both cancer cells and stem cells.It might play an important role in the growth regulation of gastric cancer,liver cancer and other cancers.

Environmental Properties of Minerals and Contaminants Purified by the Mineralogical Method

The investigation of the environmental properties of minerals, i.e., environmental mineralogy, is a branch of science dealing with interactions between natural minerals and spheres of the Earth surface as well as a reflection of global change, prevention of ecological destruction, participation in biomineralogy, and remediation of environmental pollution. Pollutant treatment by natural minerals is based on the natural law and reflects natural self-purification functions in the inorganic world, similar to that of the organic world - a biological treatment. A series of case studies related to natural self-purification, which were mostly completed by our group, are discussed in this paper. In natural cryptomelane there is a larger pseudotetragonal tunnel than that formed by [MnO6] octahedral double chains, with an aperture of 0.462-0.466 nm2, filled with K cations. Cryptomelane might be a real naturally-occurring mineral of the active octahedral molecular sieve (OMS-2). CrⅥ-bearing wastewater can be treated by natural pyrrhotite, which is used as a reductant to reduce CrⅥ and as a precipitant to precipitate CrⅢ simultaneously. Batch experiments were conducted using the CTMAB-Montmorillonite as an adsorbent for aromatic contaminants (phenol, aniline, benzene, toluene and xylenes), which are detected frequently in the leaching water from municipal waste deposits around China. The CTMAB modification has proved very effective to enhance the adsorption capacity of the sorbent. Expansion of vermiculite develops loose interior structures, such as pores or cracks, inside briquettes, and thus brings enough oxygen for combustion and the sulfation reaction. Effective combustion of the original carbon reduces the amount of dust in the fly ash.

COX-2 expression and tumor angiogenesis in colorectal cancer

AIM: Cyclooxygenase-2 (COX-2) is one of the rate-limiting enzymes in metabolism of arachidonic acid, and COX-2 inhibitors demonstrate preventive effects on cancer,especially on colorectal cancer. The underlying mechanism remains unclear. The aim of this study was to illustrate the relationship between angiogenesis and COX-2 in carcinogenesis of colorectal cancer.METHODS: One hundred and seventy patients with colorectal cancer were enrolled in our study from January 1993 to September 2001 in School of Oncology, PekingUniversity. COX-2 and VEGF expression were detected with the immunohistochemistry (IHC) technique. IHC assays were carried out with the aid of tissue microarray (TMA)procedure. Specimens from 35 of these patients were examined with reverse transcriptase PCR (RT-PCR).RESULTS: COX-2 and VEGF expressions were stronger in colorectal cancer than those in the corresponding normal tissues, at both protein and mRNA levels. One hundred patients were eligible for analysis after IHC assay of COX-2 and VEGF. The positive rate of VEGF was much higher in COX-2 positive group (47/85) than in COX-2 negative group (x^2 = 4.181, P= 0.041). The result was further verified by the result of RT-PCR (x^2 = 8.517, P = 0.003). Correlation coefficient was 0.409 after Spearman correlation analysis (P=0.015).CONCLUSION: COX-2 may be involved in the course of tumor angiogenesis of colorectal cancer and acts through VEGF.

Alpha-fetoprotein stimulated the expression of some oncogenes in human hepatocellular carcinoma Bel 7402 cells

AIM:To investigate the molecular mechanism of alphafetoprotein (AFP) on regulating the proliferation of human hepatocellular carcinoma cells.METHODS: Alpha-fetoprotein purified from human umbilical blood was added to cultured human hepatocellular carcinoma Bel 7402 cells in vitro for various treatment periods. The expression of c-fos, c-jun,and N-ras mRNA involved in proliferation and differentiation of cells was analyzed by Northern blot,and the expression of mutative p53 and p21^ras proteins was determined by Western blot.RESULTS:The results showed that AFP (20mg/L) stimulated mRNA expression of these oncogenes in Bel 7402 cells.The expression of c-fos mRNA increased by 51.1%,60.9%,96.0%,and 25.5% at 2, 6, 12, and 24 h, respectively.The expression of c-jun and N-ras mRNA reached to the maximum which increased by 81.3% and 59.9% as compared with the control alter 6h and 24h incubation with AFP, respectively.Western blot assay also demonstrated that AFP promoted the expression of mutative p53 and p21^ras proteins, and the increased rate of those proteins was 13.0%,39.9%, and 70.9%, as well as 35.2%, 102.6%, and 46.8% at 6, 12, and 24h,respectively, as compared with the control.Both human serum albumin (the same dosage as AFP) and monoclonal anti-AFP antibody failed to stimulate the expression of these oncogenes,but anti-AFP antibody could block the functions of AFP.CONCLUSION:The data indicate that AFP can stimulate the expression of some oncogenes to enhance the proliferation of human hepatocellular carcinoma Bel 7402 cells.

Solving Nonlinear Wave Equations by Elliptic Equation

The elliptic equation is taken as a transformation and applied to solve nonlinear wave equations. It is shown that this method is more powerful to give more kinds of solutions, such as rational solutions, solitary wave solutions,periodic wave solutions and so on, so it can be taken as a generalized method.

Structure analysis and expressions of a novel tetratransmembrane protein,lysosoma-associated protein transmembrane 4β associated with hepatocellular carcinoma

AIM: To analyze the structure and expressions of the protein encoded by an HCC-associated novel gene, lysosomeassociated protein transmembrane 4 β (LAPTM4B). METHODS: Primary structure and fundamental characteristics of LAPTM4B protein were analysed with bioinformatics. Expressions of LAPTM4B in HCC tissues and various cell lines were detected using polyclonal antibodies and Western blot. RESULTS: LAPTM4B encoded two isoforms of proteins with molecular masses 35-ku and 24-ku, respectively. The expression level of LAPTM4B-35 protein in HCC tissues was dramatically upregulated and related to the differentiation status of HCC tissues, and it was also high in some cancer cell lines. Computer analysis showed LAPTM4B was an integral membrane protein with four transmembrane domains. LAPTM4B showed relatively high homology to LAPTM4A and LAPTM5 in various species. CONCLUSION: LAPTM4B gene encoded two isoforms of tetratansmembrane proteins, LAPTM4B-35 and LAPTM4B-24. The expression of LAPTM4B-35 protein is upregulated and associated with poor differentiation in human HCC tissues, and also at high levels in some cancer cell lines. LAPTM4B is an original and conserved protein.

Cloning and functional characterization of two cDNAs encoding NADPH-dependent 3-ketoacyl-CoA reductased from developing cotton fibers

Genes encoding enzymes involved in biosynthesis of very long chain fatty acids were significantly up-regulatedduring early cotton fiber development. Two cDNAs, GhKCR1 and GhKCR2 encoding putative cotton 3-ketoacyl-CoAreductases that catalyze the second step in fatty acid elongation, were isolated from developing cotton fibers. GhKCR1and 2 contain open reading frames of 963 bp and 924 bp encoding proteins of 320 and 307 amino acid residues,respectively. Quantatitive RT-PCR analysis showed that both these genes were highly preferentially expressed duringthe cotton fiber elongation period with much lower levels recovered from roots, stems and leaves. GhKCR1 and 2showed 30%-32% identity to Saccharomyces cerevisiae Ybr159p at the deduced amino acid level. These cotton cDNAswere cloned and expressed in yeast haploid ybr159w? mutant that was deficient in 3-ketoacyl-CoA reductase activity.Wild-type growth rate was restored in ybr159w? cells that expressed either GhKCR1 or 2. Further analysis showed thatGhKCR1 and 2 were co-sedimented within the membranous pellet fraction after high-speed centrifugation, similar to theyeast endoplasmic reticulum marker ScKar2p. Both GhKCR(s) showed NADPH-dependent 3-ketoacyl-CoA reductaseactivity in an in vitro assay system using palmitoyl-CoA and malonyl-CoA as substrates. Our results suggest thatGhKCR1 and 2 are functional orthologues of ScYbr159p.

FTIR Characterization of the Secondary Structure of Insulin Encapsulated within Liposome

Aim To determine the secondary structure of insulin encapsulated withinliposome. Methods The secondary structure of native insulin, mixture of insulin with liposome(sample Ⅰ) and insulin encapsulated within liposome( sample Ⅱ) were determined by FTIR (FourierTransform Infrared) spectroscopy. Results The secondary structure of insulin encapsulated withinliposome(Ⅱ) are similar with the secondary structure of native insulin. The difference existed inthe amount of α-helices (from 36% of insulin to 31% of sample Ⅱ) and β-sheet(from 48% of insulinto 51% of sample Ⅱ). The content of α-helices and β-sheet of insulin in sample Ⅰ was found to bevery close to that of sample Ⅱ. The results revealed that the insulin encapsulated within liposomepossibly spread on the surface of liposome, without inserting into the liposome membrane.Conclusion The secondary structure of insulin encapsulated within liposome is similar with thenative insulin.