The pattern of gene expression in human CD34(+) stem/progenitor cells

We have analyzed the pattern of gene expression in human primary CD34(+) stem/progenitor cells. We identified 42,399 unique serial analysis of gene expression (SAGE) tags among 106,021 SAGE tags collected from 2.5 x 10(6) CD34(+) cells purified from bone marrow. Of these unique SAGE tags, 21,546 matched known expressed sequences, including 3,687 known genes, and 20,854 were novel without a match. The SAGE tags that matched known sequences tended to be at higher levels, whereas the novel SAGE tags tended to be at lower levels. By using the generation of longer sequences from SAGE tags for gene identification (GLGI) method, we identified the correct gene for 385 of 440 high-copy SAGE tags that matched multiple genes and we generated 198 novel 3' expressed sequence tags from 138 high-copy novel SAGE tags. We observed that many different SAGE tags were derived from the same genes, reflecting the high heterogeneity of the 3' untranslated region in the expressed genes. We compared the quantitative relationship for genes known to be important in hematopoiesis. The qualitative identification and quantitative measure for each known gene, expressed sequence tag, and novel SAGE tag provide a base for studying normal gene expression in hematopoietic stem/progenitor cells and for studying abnormal gene expression in hematopoietic diseases.

Modulation of retinal cell populations and eye size in retinoic acid receptor knockout mice

PURPOSE

The retinoic acid receptors are expressed from early stages of development in the diverse tissues that make up the vertebrate eye. Their loss has subtle effects on eye development. We adapted sensitive quantitative trait locus (QTL) mapping methods to assess consequences of inactivating alleles of the alpha and beta receptors, Rara and Rarb, on eye and retinal development. Rara is of particular interest because this gene is a candidate for Nnc1, a QTL that controls retinal ganglion cell proliferation.

METHODS

We studied lines of mice in which expression of the a1 isoform of Rara or all isoforms of Rarb had been disrupted by gene targeting. We measured eye weight, lens weight, retinal area, and retinal ganglion cell number in each of six genotypes (Rara and Rarb -/-, +/-, +/+; 10-25 cases/genotype).

RESULTS

Loss of either protein is associated with a small but significant loss of eye weight and retinal area. However, only the Rarb knockout has a significant effect on the ganglion cell population and the loss of both wildtype alleles leads to an 8,000 cell deficit. Surprisingly, loss of the Rara a1 isoform that is expressed in this cell population from early stages has no effect on number. Null alleles of both genes have little if any effect on lens growth.

CONCLUSIONS

Despite its expression in embryonic retina, Rara is unlikely to be the Nnc1 QTL. In contrast, Rarb, a gene that maps to Chr 14 and which is not an Nnc1 candidate gene, has a significant effect on cell number and is therefore a QTL controlling this key population. This raises the intriguing possibility that normal allelic variants of Rarb modulate the ganglion cell population in other vertebrates, including humans.

Uroplakin Ia is the urothelial receptor for uropathogenicEscherichia coli: evidence from in vitro FimH binding

The binding of uropathogenic Escherichia coli to the urothelial surface is a crucial initial event for establishing urinary tract infection because it allows the bacteria to gain a foothold on the urothelial surface, thus preventing them from being removed by micturition. In addition, it triggers bacterial invasion as well as host urothelial defense. This binding is mediated by the FimH adhesin located at the tip of the bacterial type 1-fimbrium, a filamentous attachment apparatus, and its urothelial receptor. We have prepared a biotinylated, recombinant FimH-FimC adhesin:chaperone complex and used it to identify its mouse urothelial receptor. The FimH-FimC complex binds specifically to a single 24 kDa major mouse urothelial plaque protein, which we identified as uroplakin Ia by mass spectrometry, cDNA cloning and immunoreactivity. The terminal mannosyl moieties on Asn-169 of uroplakin Ia are responsible for FimH as well as concanavalin A binding. Although FimH binds to uroplakin Ia with only moderate strength (Kd ∼100 nM between pH 4 and 9), the binding between multiple fimbriae of a bacterium and the crystalline array of polymerized uroplakin receptors should achieve high avidity and stable bacterial attachment. The FimH-FimC complex binds preferentially to the mouse urothelial umbrella cells in a pattern similar to uroplakin staining. Our results indicate that the structurally related uroplakins Ia and Ib are glycosylated differently, that uroplakin Ia serves as the urothelial receptor for the type 1-fimbriated E. coli, and that the binding of uropathogenic bacteria to uroplakin Ia may play a key role in mediating the urothelial responses to bacterial attachment.

27-hydroxycholesterol is an endogenous ligand for liver X receptor in cholesterol-loaded cells

The nuclear receptors liver X receptor alpha (LXRalpha) (NR1H3) and LXRbeta (NR1H2) are important regulators of genes involved in lipid metabolism, including ABCA1, ABCG1, and sterol regulatory element-binding protein-1c (SREBP-1c). Although it has been demonstrated that oxysterols are LXR ligands, little is known about the identity of the physiological activators of these receptors. Here we confirm earlier studies demonstrating a dose-dependent induction of ABCA1 and ABCG1 in human monocyte-derived macrophages by cholesterol loading. In addition, we show that formation of 27-hydroxycholesterol and cholestenoic acid, products of CYP27 action on cholesterol, is dependent on the dose of cholesterol used to load the cells. Other proposed LXR ligands, including 20(S)-hydroxycholesterol, 22(R)-hydroxycholesterol, and 24(S),25-epoxycholesterol, could not be detected under these conditions. A role for CYP27 in regulation of cholesterol-induced genes was demonstrated by the following findings. 1) Introduction of CYP27 into HEK-293 cells conferred an induction of ABCG1 and SREBP-1c; 2) upon cholesterol loading, CYP27-expressing cells induce these genes to a greater extent than in control cells; 3) in CYP27-deficient human skin fibroblasts, the induction of ABCA1 in response to cholesterol loading was ablated; and 4) in a coactivator association assay, 27-hydroxycholesterol functionally activated LXR. We conclude that 27-hydroxylation of cholesterol is an important pathway for LXR activation in response to cholesterol overload.

Role of AMP-activated protein kinase in mechanism of metformin action

Metformin is a widely used drug for treatment of type 2 diabetes with no defined cellular mechanism of action. Its glucose-lowering effect results from decreased hepatic glucose production and increased glucose utilization. Metformin's beneficial effects on circulating lipids have been linked to reduced fatty liver. AMP-activated protein kinase (AMPK) is a major cellular regulator of lipid and glucose metabolism. Here we report that metformin activates AMPK in hepatocytes; as a result, acetyl-CoA carboxylase (ACC) activity is reduced, fatty acid oxidation is induced, and expression of lipogenic enzymes is suppressed. Activation of AMPK by metformin or an adenosine analogue suppresses expression of SREBP-1, a key lipogenic transcription factor. In metformin-treated rats, hepatic expression of SREBP-1 (and other lipogenic) mRNAs and protein is reduced; activity of the AMPK target, ACC, is also reduced. Using a novel AMPK inhibitor, we find that AMPK activation is required for metformin's inhibitory effect on glucose production by hepatocytes. In isolated rat skeletal muscles, metformin stimulates glucose uptake coincident with AMPK activation. Activation of AMPK provides a unified explanation for the pleiotropic beneficial effects of this drug; these results also suggest that alternative means of modulating AMPK should be useful for the treatment of metabolic disorders.

[Pharmacological study on the extracts from Typhonium flagelliforme Blume]

OBJECTIVE

To study the pharmacological action of Typhonium flagelliforme Blune(TFB).

METHODS

Relieving a cough and eliminating expectoration were observed by strong aqua spray and pheol red determining methods. The antiasthmatic action was observed by whole spraying method. The analgesia and anti-inflammation were studied by the twisting test induced by acetic acid and ear swelling induced by xylene. The sedation was determined by autonomic action test. The toxicity of TFB was studied through the acute toxicity test in mice.

RESULTS

All the water, alcohol and ester extracts of TFB could significantly decrease cough times, increase phenol red outage in trachea, prolong asthma incubation period, decrease twisting times, inhibit ear swelling and decrease autonomic action times.

CONCLUSION

All water, alcohol and ester extracts of TFB have effects of relieving a cough, eliminating expectoration, antiasthmatic, analgesia, anti-inflammation and sedation. The maximum tolerances of TFB for acute toxicity were 720 g/kg(water extract), 900 g/kg (alcohol extract) 3240 g/kg(ester extract) respectively.

Miniaturized pyrosequencer for DNA analysis with capillaries to deliver deoxynucleotides

As the human genome project proceeds, various types of DNA analysis tools are required for life sciences and medical sciences including DNA diagnostics. For example, a small DNA sequencer for sequencing a short DNA is required for bed-side DNA testing as well as DNA analysis in a small laboratory. Here, a new handy DNA sequencing system (pyrosequencer) based on the detection of inorganic pyrophosphate (PPi) released by polymerase incorporation is demonstrated. The system uses the bioluminescence detection system. The key point for the miniaturized DNA sequencer is to make a deoxynucleotide triphosphate (dNTP) delivery system small and inexpensive. It has been realized by using narrow capillaries to connect a reaction chamber and four dNTP reservoirs. Each dNTP is introduced into the reaction chamber by applying a pressure to the reservoir. Compared with other microdispensers, it is much cheaper and easier. By optimizing the conditions, an excellent sequencing ability is achieved while it is a simple and inexpensive system. In most cases, more than 40 bases can be successfully sequenced. A homopolymeric region, which can not be easily sequenced by a conventional gel-based DNA sequencer, is readily sequenced with this system. The new system is successfully applied to sequence a GC rich region or a region close to a priming region where misreading frequently occurs. A rapid analysis for a short DNA was easily achieved with this small instrument.

Quantitative detection of single nucleotide polymorphisms for a pooled sample by a bioluminometric assay coupled with modified primer extension reactions (BAMPER)

A new method for SNP analysis based on the detection of pyrophosphate (PPi) is demonstrated, which is capable of detecting small allele frequency differences between two DNA pools for genetic association studies other than SNP typing. The method is based on specific primer extension reactions coupled with PPi detection. As the specificity of the primer-directed extension is not enough for quantitative SNP analysis, artificial mismatched bases are introduced into the 3'-terminal regions of the specific primers as a way of improving the switching characteristics of the primer extension reactions. The best position in the primer for such artificial mismatched bases is the third position from the primer 3'-terminus. Contamination with endogenous PPi, which produces a large background signal level in SNP analysis, was removed using PPase to degrade the PPi during the sample preparation process. It is possible to accurately and quantitatively analyze SNPs using a set of primers that correspond to the wild-type and mutant DNA segments. The termini of these primers are at the mutation positions. Various types of SNPs were successfully analyzed. It was possible to very accurately determine SNPs with frequencies as low 0.02. It is very reproducible and the allele frequency difference can be determined. It is accurate enough to detect meaningful genetic differences among pooled DNA samples. The method is sensitive enough to detect 14 amol ssM13 DNA. The proposed method seems very promising in terms of realizing a cost-effective, large-scale human genetic testing system.

The pattern of gene expression in mouse Gr-1(+) myeloid progenitor cells

To understand the pattern of gene expression in mouse myeloid progenitor cells, we carried out a genome-wide analysis of gene expression in mouse bone marrow Gr-1(+) cells using SAGE and GLGI techniques. We identified 22,033 unique SAGE tags with quantitative information from 73,869 collected SAGE tags. Among these unique tags, 64% match known sequences, including many genes important for myeloid differentiation, and 36% have no matches to known sequences and are likely to represent novel genes. We compared the expression of mouse Gr-1(+) and human CD15(+) myeloid progenitor cells and showed that the pattern of gene expression of these two cell populations had some similarities. We also compared the expression of mouse Gr-1(+) myeloid progenitor cells with that of mouse brain tissue and found a highly tissue-specific manner of gene expression in these two samples. Our data provide a basis for studying altered gene expression in myeloid disorders using mouse models.

Metabolic stabilization of benzylidene ketal M(2) muscarinic receptor antagonists via halonaphthoic acid substitution

The potential toxicological liabilities of the M(2) muscarinic antagonist 1 were addressed by replacing the methylenedioxyphenyl moiety with a p-methoxyphenyl group, resulting in M(2) selective compounds such as 3. Several halogenated naphthamide derivatives of 3 were studied in order to improve the pharmacokinetic profile via blockage of oxidative metabolism. Compound 4 demonstrated excellent M(2) affinity and selectivity, human microsomal stability, and oral bioavailability in rodents and primates.

Monoclonal anti-idiotype antibody bearing the internal image of nasopharyngeal carcinoma associated antigen

OBJECTIVE

To generate and characterize anti-idiotypic monoclonal antibody (Ab2) that bears the internal image of nasopharyngeal carcinoma (NPC) associated antigen.

METHODS

Using NPC monoclonal antibody (Ab1) as immunogen, hybridoma cells were obtained by fusion of SP2/0 myeloma cells with immunized murine spleen cells. Positive clones were screened by Sandwich ELISA and a binding inhibition test. To determine whether Ab2 possess the internal image of the original antigen or not, mice were immunized with Ab2. ELISA and the competitive inhibition assay tested anti-anti-idiotypic antibodies (Ab3) in anti-sera. Cell-mediated immunity to tumors induced by Ab2 was investigated by a delayed-type hypersensitivity response and the mouse T-cell proliferation assay.

RESULTS

Anti-idiotypic monoclonal antibodies against the monoclonal anti-NPC antibodies FC2 and HNL5 were generated that recognize NPC associated antigens. These Ab2, which were designated 2H4 and 5D3, could inhibit the binding of FC2 or HNL5 to NPC cell lines. Anti-sera from the immunized mice, which contained Ab3, could compete with FC2 or HNL5 for binding with NPC cell by a competitive inhibition assay. Mice immunized with 2H4 or 5D3 coupled with keyhole limpet hemocyanin (KLH), showed a positive and specific delayed-type hypersensitivity (DTH) reaction after stimulation by NPC cells. The mouse T cell proliferative assay indicated that there was a significantly higher proliferative response of the splenocytes in the experimental groups than that in control groups.

CONCLUSIONS

Anti-idiotypic antibodies 2H4 and 5D3 are Ab2 beta bearing the internal image of the epitope of NPC associated antigen. Either 2H4 or 5D3 expressing three-dimensional shapes that resemble the structure of natural antigens could induce humoral and cellular immune response.

Use of homogeneous time-resolved fluorescence energy transfer in the measurement of nuclear receptor activation

Nuclear receptors (NRs) are a superfamily of ligand-dependent transcription factors that mediate the effects of hormones and other endogenous ligands to regulate the expression of specific genes. NRs are clearly important targets for drug discovery. Ligand-dependent protein-protein interactions between NRs and NR coactivators (NRCoAs) are a critical step in regulation of transcription. Homogeneous time-resolved fluorescence (HTRF) energy transfer technology is sensitive, homogeneous, and nonradioactive. These characteristics make this approach attractive for developing high-throughput screening assays. The long-lived nature of the fluorescence of europium cryptate combined with a time delay in reading facilitates the homogeneous nature of the assay. Importantly, the introduction of lanthanides (with R0 values as great as 90 A in HTRF) make HTRF amenable to be used for protein-protein interactions. In this article we review, using peroxisome proliferator-activated receptor (PPAR)gamma as a model system, a novel approach for characterizing the ligand-dependent interaction between NR and NRCoA using HTRF technology and its potential uses in small-molecule screening, profiling selectivity of NR-NRCoA paired interactions, and profiling NR ligands as agonists versus partial agonists or antagonists.

[Microskin grafting in recent 15 years]

OBJECTIVE

To summarize microskin grafting in recent 15 years.

METHODS

Microskin grafting was performed in 162 patients with extensive burns. The indications and forms of the grafting, mechanization in making microsk in and outcome of wound recovered by micrografts were discussed.

RESULTS

Extremely extensive third degree burns, common extensive third degree burns and extensive granulation wound were healed byn different ways of microskin grafting. A new machine was used to mince micrografts with good clinical results. The homografts as coverture was exfoliated in either necrosis or desquamation. Scar formation was related to wound repair.

CONCLUSIONS

Microskin grafting has made progress in recent years. The orientation and even spread of micrografts are very important for good wound repair. The technic should be further improved.

[Pilot study on mutations of p53 gene in laryngeal carcinoma]

OBJECTIVE

To determine the characteristic and frequency of the point mutation of p53 gene.

METHODS

22 cases of laryngeal squamous cell carcinoma (LSCC) with positive expression of mutant p53 protein and 2 cases of normal laryngeal epithelium as control were examined by means of polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP), single strand conformation polymorphism (SSCP) and DNA sequencing analyses.

RESULTS

3 cases of LSCC had the point mutation on codons 248, 250 and 254 of exon 7 in p53 gene. None of the cases had the point mutation on codon 249.

CONCLUSION

These findings suggest that the point mutation on codon 249 of exon 7 in p53 gene may be uncommon in LSCC. SSCP and DNA sequencing analyses are sensitive and rapid methods for detecting p53 gene mutation.

Gastrointestinal stromal tumors: clinicopathological study of Chinese cases

In the present study, we reviewed 73 Chinese cases of gastrointestinal stromal tumor (GIST), and analyzed factors in evaluating malignant potential, in particular focusing on Ki-67 index and p53 expression to determine whether these can be used as prognostic indicators in GIST. The p53 positive rate was 50.7% and it was significantly higher in malignant (25/35; 71.43%) than in benign cases (13/38; 34.21%). A Ki-67 labeling index of >10% was also significantly different between malignant (23/35; 65.71%) and benign cases (14/38; 36.84%). In the cases in which the patient died, 15/21 and 14/21 cases showed expression of p53 and Ki-67, respectively; both had a higher expression than in surviving cases. Comparing the cases positive for both Ki-67 and p53 with those positive for Ki-67 or p53 alone, and those negative for both Ki-67 and p53, the latter demonstrated the best prognosis. The study also indicated that the malignant potential of GIST is correlated with the mitotic index (> or =1/10 high-power fields; HPF), tumor size (> or =5 cm), high cellularity, tumor invasive growth, tumor location, tumor hemorrhage and tumor necrosis.

Electronic structure and field-emission characteristics of open-ended single-walled carbon nanotubes

The field-emission mechanism of open-ended single-walled carbon nanotubes (SWNTs) is studied. Owing to electronic effects that directly alter the bonding mode and remarkably influence the work function, an open-ended SWNT has much better field-emission properties than a closed SWNT; owing to geometrical effects that slightly influence the work function and the amplification factor, an open-ended SWNT with relaxation has higher threshold voltage and higher current density compared to one without relaxation. It is suggested that adjusting the localized electronic states of the emitting regions, by electronic and geometrical means, could improve the field-emission properties of carbon nanotubes.

Differential gene regulation in human versus rodent hepatocytes by peroxisome proliferator-activated receptor (PPAR) alpha. PPAR alpha fails to induce peroxisome proliferation-associated genes in human cells independently of the level of receptor expresson

We compared the ability of rat and human hepatocytes to respond to fenofibric acid and a novel potent phenylacetic acid peroxisome proliferator-activated receptor (PPAR) alpha agonist (compound 1). Fatty acyl-CoA oxidase (FACO) activity and mRNA were increased after treatment with either fenofibric acid or compound 1 in rat hepatocytes. In addition, apolipoprotein CIII mRNA was decreased by both fenofibric acid and compound 1 in rat hepatocytes. Both agonists decreased apolipoprotein CIII mRNA in human hepatocytes; however, very little change in FACO activity or mRNA was observed. Furthermore, other peroxisome proliferation (PP)-associated genes including peroxisomal 3-oxoacyl-CoA thiolase (THIO), peroxisomal enoyl-CoA hydratase/3-hydroxyacyl-CoA dehydrogenase (HD), peroxisomal membrane protein-70 (PMP-70) were not regulated by PPAR alpha agonists in human hepatocytes. Moreover, other genes that are regulated by PPAR alpha ligands in human hepatocytes such as mitochondrial HMG-CoA synthase and carnitine palmitoyl transferase-1 (CPT-1) were also regulated in HepG2 cells by PPAR alpha agonists. Several stably transfected HepG2 cell lines were established that overexpressed human PPAR alpha to levels between 6- and 26-fold over normal human hepatocytes. These PPAR alpha-overexpressing cells had higher basal mRNA levels of mitochondrial HMG-CoA synthase and CPT-1; however, basal FACO mRNA levels and other PP-associated genes including THIO, HD, or PMP-70 mRNA were not substantially affected. In addition, FACO, THIO, HD, and PMP-70 mRNA levels did not increase in response to PPAR alpha agonist treatment in the PPAR alpha-overexpressing cells, although mitochondrial HMG-CoA synthase and CPT-1 mRNAs were both induced. These results suggest that other factors besides PPAR alpha levels determine the species-specific response of human and rat hepatocytes to the induction of PP.

[Study on the photoluminescence spectrum of nickel passivation treatment of porous silicon]

A new method for electrolysis passivation treatment of porous silicom (PS) in NiCl2 is reported in this paper. The photoluminescence (PL) spectra of PS treated in different time is observed, the spectra show that peak intensity is 2.5 times stronger than that without treatment, peak wavelength is 33 nm blue shift when PS is treated properly. The phenomenon caused is that the results of the SiHx change into SiNix when replaced H by Ni on surface of PS.

[Characteristics of litter and its contained water in three succession communities in Dinghushan Mountain]

Studies on the characteristics of litter and its contained water in three succession communities in Dinghushan Mountain showed that the standing mass of litter was in the order of pine forest > mixed forest > broad-leaved forest, and the annual litterfall was broad-leaved forest > mixed forest > pine forest, indicating that the return rate of nutrients was lower in pine forest than in broad-leaved forest. The proportion of leaf litter decreased in the order of pine forest > mixed forest > broad-leaved forest, and that of branch, flower, and fruit litter was on the contrary, because the broad-leaved forest had the largest amount of branches and the biggest scope of canopy. The staturation water content of litter in pine forest, mixed forest and broad-leaved forest was 329.0%, 313.0% and 295.0%, respectively, showing no significant difference, but the water content of litter in three communities differed significantly, followed the order of broad-leaved forest > mixed forest > pine forest. The evaporation ratio of litter water to free water in broad-leaved forest, mixed forest and pine forest was 78.9%, 82.45% and 91.22%, respectively.

Gene expression profiling in human fetal liver and identification of tissue- and developmental-stage-specific genes through compiled expression profiles and efficient cloning of full-length cDNAs

Fetal liver intriguingly consists of hepatic parenchymal cells and hematopoietic stem/progenitor cells. Human fetal liver aged 22 wk of gestation (HFL22w) corresponds to the turning point between immigration and emigration of the hematopoietic system. To gain further molecular insight into its developmental and functional characteristics, HFL22w was studied by generating expressed sequence tags (ESTs) and by analyzing the compiled expression profiles of liver at different developmental stages. A total of 13,077 ESTs were sequenced from a 3'-directed cDNA library of HFL22w, and classified as follows: 5819 (44.5%) matched to known genes; 5460 (41.8%) exhibited no significant homology to known genes; and the remaining 1798 (13.7%) were genomic sequences of unknown function, mitochondrial genomic sequences, or repetitive sequences. Integration of ESTs of known human genes generated a profile including 1660 genes that could be divided into 15 gene categories according to their functions. Genes related to general housekeeping, ESTs associated with hematopoiesis, and liver-specific genes were highly expressed. Genes for signal transduction and those associated with diseases, abnormalities, or transcription regulation were also noticeably active. By comparing the expression profiles, we identified six gene groups that were associated with different developmental stages of human fetal liver, tumorigenesis, different physiological functions of Itoh cells against the other types of hepatic cells, and fetal hematopoiesis. The gene expression profile therefore reflected the unique functional characteristics of HFL22w remarkably. Meanwhile, 110 full-length cDNAs of novel genes were cloned and sequenced. These novel genes might contribute to our understanding of the unique functional characteristics of the human fetal liver at 22 wk.

[Carbon equilibrium in Larix gmelinii forest and impact of global change on it]

In order to provide a methodological demonstration for the study of C cycle in forest, the CENTURY model was applied to simulate the C cycle in Larix gmelinii forest and to approach the impact of global change on it. The results showed that the Larix gmelinii forest served as a C sink, with an annual net absorption of 2.65t.hm-2. Climate change and increased atmospheric CO2 concentration benefited for the net primary production (CNPP) and net C absorption capacity of forests in North China. When the atmospheric temperature was increased by 2 degrees C, the gross biomass and NPP of Larix gmelinii forest increased, while soil C content decreased, and the variation of these three indices was bigger when the precipitation was decreased by 20% than increased by 20%, indicating that the limiting factor for the forest growth in this area is atmospheric temperature, while precipitation is abundant or even too much.

[Characteristics and quantitative simulation of stomatal conductance of Aneurolepidium chinense]

Based on field measurements of stomatal conductance and photosynthesis of Aneurolepidium chinense, the dynamic characteristics and the relationship between stomatal conductance and environmental conditions were examined to develop a leaf stomatal conductance model for A. chinense. The results showed that the variation of stomatal conductance of A. chinense was closely correlated with environmental factors, such as physiologically active radiation (PAR), vapor pressure deficit (VPD) and air temperature (Ta). The daily variation of A. chinense stomatal conductance could be described as M-type curve at fair-weather, but [symbol: see text]-type curve at cloudy weather. The value of stomatal conductance increased with the increase of PAR or Ta, but decreased with the increase of VPD. The relationship between stomatal conductance(gs) and environmental factors could be expressed as: gs = PAR(2.01 Ta2 + 147.74 Ta2321.11)/((444.62 + PAR)(-538.04 + VPD)). This model would be helpful to simulate the dynamical photosynthesis of leaf and canopy and to further simulate the NPP of ecosystems and the exchange of water and heat among the soil-plant-atmosphere continuum.

Generation of high-quantity and quality tag/ditag cDNAs for SAGE analysis

The serial analysis of gene expression (SAGE) technique is an important tool for genome-wide gene expression analysis. However, the requirement of a large amount of mRNA for the analysis and the difficulties in generating high-quality tag and ditag fragments for the construction of a SAGE library often interfere with the successful performance of the SAGE technique. We developed two procedures to solve these issues: (i) introducing low-cycle PCR amplification of the 3' cDNA before the BsmFI digestion of the 3' cDNAs and (ii) gel purifying the BsmFI-released tag fragments before ditag formation. These modifications provide a large quantity of initial 3' cDNAs and high-quality tags and ditags for the construction of SAGE libraries.

The domains of glycoprotein D required to block apoptosis depend on whether glycoprotein D is present in the virions carrying herpes simplex virus 1 genome lacking the gene encoding the glycoprotein

An earlier report showed that viruses lacking the open reading frames encoding glycoproteins J and D but containing the glycoprotein D in their envelopes (gD-/+ stocks) and viruses lacking both the open reading frames and the glycoproteins in their envelopes (gD-/- stocks) induce apoptosis (G. Zhou, V. Galvan, G. Campadelli-Fiume, and B. Roizman, J. Virol. 74:11782-11791, 2000). Furthermore, apoptosis was blocked by delivery in trans of genes expressing glycoprotein D or J. Whereas gD-/- stocks attach but cannot initiate productive infection, gD-/+ stocks infect cells and produce gD-/- progeny virus. The difference in the infectivity of these two stocks suggested the possibility that the requirements for blocking apoptosis may be different. To test this hypothesis, we cloned into baculoviruses the entire wild-type glycoprotein D (Bac-gD-WT), the ectodomain only (Bac-gD-A), the ectodomain and the transmembrane domain (Bac-gD-B), the ectodomain and the cytoplasmic domain without the transmembrane domain (Bac-gD-C), or the transmembrane domain and the carboxyl-terminal cytoplasmic domain (Bac-gD-D). We report the following. Apoptosis induced by gD-/+ stocks was blocked by delivery in trans of recombinant baculovirus Bac-gD-WT, Bac-gD-A, Bac-gD-B, or Bac-gD-C but not of Bac-gD. Apoptosis induced by gD-/- stocks was blocked by Bac-gD-WT or by a mixture of Bac-gD-B and Bac-gD-D but not by any baculoviruses expressing truncated glycoprotein D alone or by the mixture of Bac-gD-A and Bac-gD-D. We conclude that the requirements to block apoptosis induced by the two virus stocks are different. The gD ectodomain is sufficient to block apoptosis induced by gD, whereas both the ectodomain and the cytoplasmic domain are required to block apoptosis induced by gD-/- stocks. The results indicate that in the case of gD-/- stocks, the transmembrane domain is required either to deliver the ectodomain to the appropriate intracellular compartment or to form multimeric constructs which virtually reconstitute gD through the interaction of transmembrane domains.

A Simple Quantitative FT-IR Approach for the Study of a Polymorphic Transformation Under Crystallization Slurry Conditions

The pharmaceutical compound (2R,3S)-2-([(1R)-1-[3,5-bis(trifluoromethyl)phenyl]ethyl]oxy)-3-(4-fluorophenyl)morpholine hydrochloride (denoted here as Compound X), has been found to crystallize in at least two polymorphic forms. Using only two frequencies (1009 and 1058 cm(-1)) in the infrared, a linear (R=0.998) calibration plot, consisting of the ratio of the peak absorbances plotted against polymorph concentration, was constructed. This plot allowed the quantification of binary mixtures of polymorphs ranging from <3 to approximately 100 wt% Form II in Form I. Spectra were acquired in transmission mode using mineral oil (Nujol) mull sample preparation, for reasons of compatibility with wet cake and slurry samples. The transformation of the less thermodynamically stable polymorph (Form II) to the more stable form (Form I), in stirred methyl isobutyl ketone (MIBK) slurries, was monitored spectroscopically as a function of time. Performing the experiment at various temperatures allowed the energy of activation for the process to be estimated (42 kJ/mol).