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Heat shock protein 90 (Hsp90) is a protein produced by plants in response to adverse environmental stresses. In this study, we identified and analyzed Hsp90 gene family members using a bioinformatic method based on genomic data from tomato (Solanum lycopersicum L.). The results illustrated that tomato contains at least 7 Hsp90 genes distributed on 6 chromosomes; protein lengths ranged from 267-794 amino acids. Intron numbers ranged from 2-19 in the genes. The phylogenetic tree revealed that Hsp90 genes in tomato (Solanum lycopersicum L.), rice (Oryza sativa L.), and Arabidopsis (Arabidopsis thaliana L.) could be divided into 5 groups, which included 3 pairs of orthologous genes and 4 pairs of paralogous genes. Expression analysis of RNA-sequence data showed that the Hsp90-1 gene was specifically expressed in mature fruits, while Hsp90-5 and Hsp90-6 showed opposite expression patterns in various tissues of cultivated and wild tomatoes. The expression levels of the Hsp90-1, Hsp90-2, and Hsp90- 3 genes in various tissues of cultivated tomatoes were high, while both the expression levels of genes Hsp90-3 and Hsp90-4 were low. Additionally, quantitative real-time polymerase chain reaction showed that these genes were involved in the responses to yellow leaf curl virus in tomato plant leaves. Our results provide a foundation for identifying the function of the Hsp90 gene in tomato.

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The entire genome of the A/Chicken/Hubei/C1/2007 (H9N2) virus, isolated from central China in 2007, was completely sequenced and phylogenetically analyzed. Phylogenetic analysis demonstrated that A/Chicken/Hubei/C1/2007 (H9N2) virus represents multiple reassortant lineages, with genes coming from the early mainland China strain (Ck/Beijing/1/94), an H9N2 virus with special genotype (Ck/shanghai/F/98) and other lineages from poultry in Asia. Infection studies indicated that A/Chicken/Hubei/C1/2007 (H9N2) virus replicated efficiently in MDCK cells and in BALB/c mice. The H9N2 virus also replicated to high titers in chicken respiratory tracts and caused overt clinical signs in chickens. Our results suggest that attention should be paid to the natural evolution of H9N2 influenza viruses and to the control of H9N2 influenza viruses in animals.

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The effect of the extracts of Epimedium brevicornum Maxim. was investigated on proliferative activity in vitro. The osteoblast-like UMR106 cells was employed as an osteoblast model. The EtOH extract and the n-butanol fraction from the crude extract were found to show proliferation stimulating activity. Three flavonoid compounds (icariin, epimedin B and epimedin C) were isolated from this fraction by activity-guided assay, and the effects on cell proliferation were studied. Icariin produced the most significant promoting effect on the proliferation in osteoblast-like UMR106 cells. The results suggested that E. brevicornum Maxim. extracts might have potential activity against osteoporosis, and flavonoids such as icariin might be the active constituents stimulating osteoblasts.

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While making use of the inside-out membrane patch, we examined the effects of caffeine and heparin on unitary currents of the large conductance Ca(2+)-dependent K+ (maxi-K+) channel in the rabbit portal vein. About half of the inside-out membranes we used contained a functional Ca(2+)-store site which facilitated modification of the maxi-K+ channel. When high-K+ solution containing 0.05mM EGTA was superfused in the bath, simultaneous openings of more than 20 maxi-K+ channels were observed in 39 of 83 patch membranes, and multi-channel opening appeared periodically or continuously at the holding potential of -10mV. Most channel activities of these patch membranes were inhibited by caffeine or heparin, and some heparin-insensitive channel activities were inhibited by caffeine. The remaining patch membranes (44 out of 83) showed low activity of the maxi-K+ channel, and neither caffeine nor heparin modified channel activity. Therefore, in our experimental set-up, half the number of excised patch membranes contained a Ca2+ store site. Most Ca2+ store sites have inositol 1,4,5-trisphosphate (InsP3)-activated Ca2+ release (IACR) and caffeine-activated Ca2+ release (CACR) channels and few lack the IACR channel. The mechanisms of activation of the maxi-K+ channel in relation to release of Ca2+ from the store sites can be examined in detail using the approaches we have described.

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Pinacidil, a potassium-channel opener, inhibited the ryanodine-sensitive oscillatory outward potassium current induced by Ca released from an intracellular store. Glibenclamide, a blocker of the ATP-sensitive K-channel, prevented the action of pinacidil, suggesting the presence of an additional site (to K channels) for the vasodilator actions of pinacidil at which glibenclamide can act as an antagonist.

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1. Effects of adenosine 5'-triphosphate (ATP) on ionic currents of dispersed smooth muscle cells of the rabbit portal vein were investigated using the voltage-clamp procedure. 2. ATP (greater than or equal to 300 microM) produced transient and maintained inward currents. The former was inactivated within a few seconds, but the latter lasted more than several minutes. The transient but not the maintained current was blocked by pre-treatment with alpha,beta-methylene adenosine 5'-triphosphate (AMP-CPP). The amplitude of the latter was increased by ATP in a concentration-dependent manner. The following investigations were made on the ionic mechanism of the ATP-induced maintained inward current. 3. In 2.5 mM-Ca(2+)-containing tetraethylammonium chloride (TEA-Cl) solution (2.5 mM-Ca(2+)-TEA+ solution), the reversal potential for the ATP-induced inward current was close to the Cl- equilibrium potential, and in 140 mM-Na+ (nominally Ca(2+)-free or 0.3 mM-EGTA-containing) solution, the reversal potential was coincident with the Na+ equilibrium potential. 4. In 2.5 mM-Ca(2+)-TEA+ solution but not in 140 mM-Na+ solution and in physiological salt solution (PSS), niflumic acid (10 microM), a Cl- channel blocker, and Cl(-)-deficient perfusate in the pipette markedly inhibited the ATP-induced inward current. These results imply that in 2.5 mM-Ca(2+)-TEA+ solution the ATP-activated ion channel may admit Ca2+ which then accelerates the Ca(2+)-dependent Cl- current, but in 140 mM-Na+ solution and in PSS this channel may admit only Na+. 5. Intracellular perfusion of guanosine 5'-O-(3-thio triphosphate (GTP gamma S) did not provoke the current, but significantly increased the amplitude of the ATP-induced inward current in 2.5 mM-Ca(2+)-TEA+, 140 mM-Na+ and 2.5 mM-Ba(2+)-containing TEA+ (2.5 mM-Ba(2+)-TEA+) solutions. On the other hand, intracellular perfusion of guanosine 5'-O-(2-thiodiphosphate) (GDP beta S) reduced the amplitude of the ATP-induced inward current in the above solutions. 6. A low concentration of ATP (30 microM) transiently augmented the amplitude of the voltage-dependent Ca2+ current recorded in both 2.5 mM-Ca(2+)-TEA+ solution and PSS, but a high concentration of ATP (3 mM) consistently inhibited the voltage-dependent Ca2+ current in both solutions (4 mM-EGTA in the pipette). Such inhibition was partly prevented by application of 20 mM-EGTA in the pipette.(ABSTRACT TRUNCATED AT 400 WORDS)

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Using a whole-cell clamp technique on longitudinal smooth muscle cells of the rabbit ileum, it was found that the rate of decay of the macroscopic Ba current evoked by depolarization (to +20 mV) was not modified by changing the holding potential from -60 mV to -30 mV. Cadmium (20 microM) left only a small transient inward current. Using the patch clamp technique with cell-attached configuration, only one type of unitary Ba current, with conductance of 25 pS was obtained in 100 mM Ba solution. The conductance depended on the external Ba concentration, had a dissociation constant of 19 mM and maximum conductance of 42 pS, suggesting that the Ca channel is of the L-type. Depolarizing pulses (to 0 mV and 150 ms duration) delivered at a frequency of 0.5 Hz (high frequency) evoked a unitary Ba current with low open probability (p less than 0.3). However 65-75% of depolarizing pulses evoked no unitary Ba current ("blank" sweep). On the other hand, depolarizing pulses at 0.033 Hz (low frequency) reduced the number of "blank" sweeps (20-50%), and increased the fraction of sweeps with high open probability (p greater than 0.5). Thus, the channel activity may depend on the stimulus frequency. Nifedipine, in both stimulus conditions, reduced the open probability of the channel due to an increase in the fraction of "blank" sweeps to a greater extent than to a decrease in the time constant of open-times.

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