An E6 gene from sea island cotton (Gossypium barbadense) was expressed specifically in cotton fiber cells to transfer functions to cultivated species for better transgenic engineering. The regulatory activity of the E6 promoter region was then studied by isolating a 614-bp fragment of the 5'-flanking region from upland cotton (Gossypium hirsutum CRI-12) to produce a green fluorescent protein (GFP) reporter construct for analysis of tissue-specific expression in transgenic tobacco seedlings. Fluorescent analyses indicate that the relatively short E6 promoter is sufficient to direct green fluorescent protein expression specifically in the leaf trichomes (hair cells) of the transgenic tobacco plants. As cotton fibers are also unicellular trichomes that differentiate from epidermal cells of developing cotton ovules, the result suggests that the relatively short E6 promoter can serve as a fiber-specific expression promoter for genetic engineering to improve cotton fiber quality.

Alkaline phosphatase from Pinctada fucata was inactivated by o-phthalaldehyde (OPA). The inactivation followed pseudo first-order kinetics with a second rate constant of 0.167 (mmol/L)?1?min?1 at pH 7.5 and 25°C. A Tsou's plot analysis showed that inactivation occurred upon formation of one isoindole group. The OPA-modified enzyme lost the ability to bind with the specific affinity column and the presence of substrates or competitive inhibitors protected the enzyme from inactivation. The results revealed that the OPA-reaction site was at the enzyme substrate binding site. Prior modification of the enzyme by lysine or histidine specific reagent abolished formation of the isoindole derivatives, suggesting that lysine and histidine residues were involved in the OPA-induced inactivation. Taken together, OPA inactivated the alkaline phosphatase from Pinctada fucata by cross-linking lysine and histidine residues at the active site and formed an isoindole group at the substrate binding site of the enzyme.

The present study is expected to provide better understanding of how exo-β-glucanase acts on the biochemo-rheological property of the cell wall, and thus the regulation mechanism of pollen tube growth. A polymerase chain reaction (PCR)-based strategy and cDNA library screening were used to clone an exo-β-glucanase gene (LP-ExoI) from Lilium longiflorum pollen tubes. The LP-ExoI sequence showed a high level of homology to that of reported plant exo-β-glucan hydrolases. Phylogenetic analysis demonstrated that there was close relationship between LP-ExoI and other exo-glucan hydrolases in Poacea plants. Northern analysis indicated that LP-ExoI transcripts stored in pollen grains at low levels; LP-ExoI transcription level enhanced at 2 h after the onset of pollen incubation and remained relatively high during pollen tube elongation. Moreover, the expression of LP-ExoI was undetectable in petals, filaments, stigmas, styles, ovaries, leaves, and stems. These results suggest that LP-ExoI gene is a late pollen gene, specifically contributing to the regulation of lily pollen germination and pollen tube growth.

The neuron protective activity of the chemical constituents from Rheum nanum and Rheum sublanceolatum in vitro was investigated using cultured embryonic mouse cortical cells exposed to oxygen-glucose deprivation. The protective effect was quantitatively evaluated by measuring the lactate dehydrogenase release rate. Most of the compounds reduce the lactate dehydrogenase release rate, including emodin, chrysophanol-8-O-β-D-glucopyranoside, 6-hydroxymusizin-8-O-β-D-glucopyranoside, gnetin C, torachrysone-8-O-β-D-glucopyranoside, and maesopsin, and all possess potent neuron protective activity. Chrysophanol and aloe-emodin exhibit neuron protection only at low concentrations. Emodin-8-O-β-D-glucopyranoside protects the neuron cells at high concentration. Aloe-emodin-8-O-β-D- glucopyranoside is inactive.

Trichosanthin (TCS) is a plant toxin with ribosome-inactivating activity. TCS can be internalized by the host cells and then attacks the ribosomes resulting in cell death. However, the manner for endocytic uptake of TCS is not well understood. The present work investigates the endocytosis pathway of TCS in human choriocarcinoma cells. The different endocytic mechanisms are interfered by potassium depletion, cholesterol-extraction/addition, or treatments of various drugs. The experiments detect their effects on the TCS-uptake. The results show that a large portion of the TCS can be internalized by clathrin-dependent, as well as by clathrin-independent but cholesterol-dependent endocytosis in human choriocarcinoma cells.

Porous multi-channel chitosan conduits were fabricated using a novel phase-separation technique with an axial temperature gradient. First, porous chitosan tubes were made with a mold that was composed of two concentric polytetrafiuoroethylene tubes. Then 1%-3% (w/v) chitosan solution was injected into the chitosan tube while the two ends of the tube were closed with steel rods. Then the outside of the tube was wrapped with a layer of thermal insulating material to reduce the heat transfer through the outside, and the tubes were placed in a freezer. The resulting phase separation then occurred in the presence of an axial temperature gradient. The porosity, microtubule diameter, and orientation were controlled by adjusting the polymer concentration and temperature gradient. After the preparation course, no poisonous substances remained on the conduits. The mechanical properties, swelling, and biodegradability of the chitosan conduits were investigated, and a scanning electron microscope was used to observe the tubular morphology and growth of neuroblastoma cells (N2A, mouse) in the conduits. The results demonstrate that the multi-channel chitosan conduits have suitable mechanical strength, swelling, degradation properties, and nerve cell affinity, so they hold promise for use as neural tissue engineering scaffolds.

The physical and chemical properties of four kinds of modified chitosan materials made by blending chitosan with polyvinylpyrrolidone (PVP) were investigated. All four of these modified chitosan materials were hydrophilic with water contact angles ranging from 59° to 69°. Fourier transform-infrared spectra of the modified materials showed a new band at 1288 cm?1, implying formation of a surface physical interpenetrating network structure. Enzyme linked immunosorbent assay results indicated that much less fibronectin was adsorbed on the modified materials than on only chitosan. The viability of MC3T3-E1 osteoblasts cultured on the materials was assessed by 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl- 2H-tetrazolium bromide assay. The results show that adding PVP10000 into the chitosan promotes adhesion of MC3T3-E1 osteoblasts on the modified materials, but has no effect on cell growth and proliferation; while adding PVP40000 reduces cell adhesion, growth, and proliferation. The results suggest that the increased hydrophilicity of the material surface does not always improve its biocompatibility, which will influence the selection and design of biomaterials.

SecA is the essential component of the signal-peptide dependent translocation pathway in Escherichia coli (E.coli). The structure and function of SecA must be known to understand the molecular mechanism of preprotein translocation. The high flexibility of SecA causes a dynamic conformational heterogeneity which presents a barrier to the growth of crystals of high diffraction quality. Electron microscopy was used to resolve the macromolecular structure of SecA in solution by negative staining and single particle analysis at a resolution of 2.9 nm. The structure of E. coli SecA is similar to the dimeric form of Bacilius subtilis SecA and is 10 nm?0 nm? nm in size.

Porous, two-ply tubular chitosan conduits for guided tissue regeneration were fabricated by combining the textile technique (inner layer) with the thermally induced phase separation process (outer layer). A hollow chitosan tube was prepared using an industrial warp knitting process with chitosan yarns. Then, an appropriate diameter mandrel was inserted into the pre-fabricated tube. The tube and the mandrel were dipped into the chitosan solution together, taken out, and freeze-dried. After being neutralized in alkaline solution and dried at room temperature, the mandrel was removed to create the chitosan tubular scaffold. Scanning electron micrographs show that the resulting tubes have a biphasic wall structure, with a fibrous inner layer and a semipermeable outer layer. The swelling properties and the mechanical strength before and after in vitro degradation were investigated. The biocompatibility of the scaffolds was also investigated by co-culturing neuroblastoma cells (N2A, mouse) with the scaffolds. The results suggest that these chitosan tubular scaffolds are useful for the regeneration of tissues requiring a tubular scaffold.

DOF is a novel family of plant-specific proteins that share a unique and highly conserved DNA binding domain with one CX2CX21CX2C zinc finger motif. In this study, the Osdof28 gene, which codes a characteristic amino acid sequence of the DOF transcription factor family, was screened from rice (Oryza sativa japonica) using a yeast one-hybrid assay. Great amounts of the Osdof28 transcripts were found to accumulate in stems and leaves, with less in the roots, and no detectable transcription found in the germs. Osdof28 can be induced by salicylic acid and INA, which suggests that it may be related to the plant systemic acquired resistance (SAR). The relationship was confirmed through biological induction of SAR using Xanthomonascampestrispv. oryzae, with more expression of Osdof28 observed in the systemic tissues after infection.

Equilibrium guanidinium chloride (GdmCl)-induced unfolding of arginine kinase (AK) was investigated by enzymatic activity, intrinsic fluorescence, 8-anilinonaphthalene-1-sulfonic acid (ANS) fluorescence, circular dichroism (CD) spectrum, and size-exclusion chromatography. The measurements showed that AK unfolded through two equilibrium intermediates: the molten globule state and the partly folded state. Both intermediates have no enzyme activity. The molten globule state exists at 0.4-0.8 mol/L GdmCl, perhaps after the N-terminal domain has unfolded but the C-terminal domain is still intact. The partly folded state occurs at 1.1-1.5 mol/L GdmCl with a hydrodynamic volume no more than 1.6-fold larger than the native state and a pronounced far UV-CD signal. Its ANS fluorescence intensity is about 50% of the molten globule state. This partly folded state shares similarities with the “burst” kinetic intermediate of protein folding.

Spatial heterogeneity and stability are fundamental indices for describing vegetation communities. The spatial distribution characteristics of the vegetation in Nenjiang region of northeastern China were evaluated using a variance power-law model. The data fits the model well with estimates given for the levels of heterogeneity for not only single species but also the community as a whole. The linear regression indicates that the species in the community exhibit a consistently organized spatial pattern, as is often discovered in field surveys but rarely seen in artificial systems. The species deviations from the regression line, which exhibit a leptokurtic distribution, may reflect the variability of the community. Thus, the model provides a general tool for management and regulation of ecosystems, especially where there is human disturbances.

The OsDREB1 gene from rice encodes a transcription factor belonging to the DREBP transcription factor subfamily. Many DREBP transcription factors regulate gene expression in response to drought, high-salt, and cold stresses by binding specifically to the dehydration-responsive element (DRE). DRE-binding proteins, such as CBF1, DREB1A, and DREB2A, have been cloned from Arabidopsis thaliana and have been proved to play an important role in stress response of Arabidopsis and several other plants. In this study, the OsDREB1 gene was transferred to tobacco plants by the Agrobacterium-mediated transfer method, and 16 transgenic plants were identified. PCR analysis demonstrates that the foreign genes have been integrated into the tobacco genome. Results of freezing stress experiments indicate that the transgenic plants have enhanced cold tolerance.

Amyloid precursor protein (APP) plays a critical role in the formation of Alzheimer's disease (AD). The intracellular domain APP (AID) was suggested to cause neurotoxicity in the nucleus. To investigate the functions AID, yeast two-hybrid screening was performed to identify the proteins which interact with AID. The human brain cDNA library was screened using pGBKT7-AID as a bait, and several positive clones were identified. One of them encodes a part of the human stathmin-like 2 protein (STMN2). The interaction between STMN2 and APP implies that STMN2 may have an important function in APP-mediated AD formation.

The effect of TACO1-299, the N-terminal truncation of TACO, on phorbol 12-myristate 13-acetate (PMA)-induced U937 cell adhesion was investigated. Full-length TACO and several truncations were overexpressed in U937 cells. The effects of the expressed proteins on U937 cell adhesion mediated by PMA-induced differentiation were observed by fluorescence microscopy. The results show that the overexpression of TACO1-299 inhibits cell adhesion while overexpressions of the other proteins do not have this effect. The actin-binding capability of TACO1-299 was investigated and the results show that TACO1-299 lacks the ability of TACO to bind F-actin. The inhibitive effect of TACO1-299, the functional domain of TACO, suggests that TACO may play a role in cell differentiation mediating adhesion of monoblastic leukemia cells.

Nuclear magnetic resonance (NMR) can noninvasively monitor intracellular concentrations and kinetic properties of numerous inorganic and organic compounds. A 31P NMR surface coil was used in vivo to dynamically measure phosphocreatine (PCr), adenosine triphosphate (ATP), and intracellular inorganic phosphate (Pi) levels in mouse brain during ischemia-reperfusion to study the damage of cerebral tissues caused by ischemia and effects of herbs on cerebral energy metabolism during ischemia-reperfusion. The study provides dynamic brain energy metabolism data during different periods. The data show that some herbs more rapidly increase the PCr level during the recovery phase than in the control group.

A soluble matrix protein P14 with an apparent molecular mass of 14.5 kDa was isolated from fragmented nacre of pearl oysters (Pinctada fucata) treated with 10% NaOH solution to investigate the nacre matrix proteins and their effect on the CaCO3 crystal. The protein was characterized by gel exclusion chromatography and reversed-phase high performance liquid chromatography after demineralization by 10% acetic acid. The X-ray diffraction pattern of P14 crystals indicates that P14 plays an important role in nacre biomineralization. P14 can induce aragonite formation, stimulate CaCO3 crystal formation, and accelerate aragonite precipitation. Heating of the acid insoluble nacre residue, which was named conchiolin, in 10% sodium dodecyl sulfate solution supplemented with 10% β-mercaptoethanol solution for 10-20 min at about 100°C gave two other soluble proteins having molecular masses of 19.4 kDa and 25.0 kDa. The present study suggests that these two proteins are linked to the insoluble organic matrix by disulfide bridges because the extraction yield increases when β-mercaptoethanol is added to the medium.

Many of the effects of Ca2+ signaling are mediated through the Ca2+/calmodulin complex and its acceptors, the Ca2+/calmodulin-dependent protein kinases, including PSKH1. Studies of the proteins involved in the calcium metabolism in oysters will help elucidate the pearl formation mechanism. This paper describes a full-length PSKH1 cDNA isolated from pearl oyster Pinctada fucata. Oyster PSKH1 shares 65% homology with human PSKH1 and 48% similarity with rat CaM kinase I in the amino acid sequence, and contains a calmodulin-binding domain. The results of semi-quantitative reverse transcription-polymerase chain reaction and in situ hybridization revealed that oyster PSKH1 mRNA is highly expressed in the outer epithelial cells of the mantle pallial and in the gill epithelial cells. These studies provide important information describing the complex Ca2+ signaling mechanism in oyster calcium metabolism.

Some monoclonal antibodies (mAbs) could inhibit infection by HIV-1. In this study, four mAbs against HIV-1 gp41 were prepared in mice. All four mAbs could bind to the recombinant soluble gp41 and recognize the native envelope glycoprotein gp160 expressed on the HIV-Env+ CHO-WT cell in flow cytometry analysis. Interestingly, the results show that all four mAbs purified by affinity chromatography could inhibit HIV-1 Env-mediated membrane fusion (syncytium formation) by 40%-60% at 10 μg/mL, which implies potential inhibitory activities against HIV-1.

The microbial populations were investigated in two groundwater samples, GW-H and GW-S, which represented heavily and slightly polluted aquifers by a seaside landfill. The concentrations of dissolved redox-relevant species suggested that iron-reduction/sulfate-reduction and denitrification were major redox processes for GW-H and GW-S. The dominant microbial populations were determined using restriction fragment length polymorphism analyses of 16S rRNA gene clone libraries. These microbes were then further studied by sequencing and phylogenetic analyses. The results indicate an obvious variation of the dominant populations between the two samples. The coexistence of sequences related to denitrifiers, sulfur-reducers, and methanotrophic bacteria was found in the GW-S sample, and a sequence associated with a sulfate-reducer was also found in the GW-H sample using molecular analyses. These results suggest that the molecular approach may be an important supplement to other approaches in characterizing the redox processes in polluted aquifers.