The Mirror transcription factor links signalling pathways in Drosophila oogenesis

Many genetic cascades are conserved in evolution, yet they trigger different responses and hence determine different cell fates at specific times and positions in development. At stage 10 of oogenesis, mirror is expressed in anterior-dorsal follicle cells, and we show that this is dependent upon the Gurken signal from the oocyte. The fringe gene is expressed in a complementary pattern in posterior-ventral follicle cells at the same stage. Ectopic expression of mirror represses fringe expression, thus linking the epidermal growth factor receptor (EGFR) signalling pathway to the Fringe signalling pathway via Mirror. The EGFR pathway also triggers the cascade that leads to dorsal-ventral axis determination in the embryo. We used twist as an embryonic marker for ventral cells. Ectopic expression of mirror in the follicle cells during oogenesis ultimately represses twist expression in the embryo, and leads to similar phenotypes to the ectopic expression of the activated form of EGFR. Thus, mirror also controls the Toll signalling pathway, leading to Dorsal nuclear transport. In summary, we show that the Mirror homeodomain protein provides a link that coordinates the Gurken/EGFR signalling pathway (initiated in the oocyte) with the Fringe/Notch/Delta pathway (in follicle cells). This coordination is required for epithelial morphogenesis, and for producing the signal in ventral follicle cells that determines the dorsal/ventral axis of the embryo.

[The clinical features and study on therapeutic effects of fungal keratitis]

OBJECTIVE

To review the clinical features and therapeutic effects of fungal keratitis (FK).

METHODS

110 cases (110 eyes) with the disease were divided into two types: hyphomycetic keratitis in 94 eyes and candida keratitis in 16 eyes. The clinical features and therapeutic effects of the two types were observed and compared.

RESULTS

The hyphomycetic keratitis generally had a plant traumatic history. The border of corneal infiltration was not clear with feather edges, and had a tendency to penetrate into the deep stroma of cornea. There were endothelial plaques, hypopyon and bad therapeutic effects. The pathogenicity of cardida keratitis (CK) was related to the local long-term use of glucocorticoid, the fungus seldom expanded into the deep corneal layers and infiltrated into the inner eye. Its therapeutic effects were better. The border of CK was characterized with limitations, and was clear.

CONCLUSIONS

The clinical features of the two types are different. The clinical features caused by different or the same pathogenic fungi show great variations. Early diagnoses, correct use of medicine and operation are the key points to increase the curative rate.

Immunohistochemical and ultrastructural study of clinically nonfunctioning pituitary adenomas

Sixty-five clinically nonfunctioning pituitary adenomas were studied by immunohistochemistry, and 12 cases were also analyzed by electron microscopy. Thirty-nine cases (60%) were immunohistochemically identified as hormone-producing adenomas. Six adenomas produced multiple hormones. Electron microscopy found seven null cell adenomas and five oncocytomas. The oncocytomas had a significantly higher incidence of hormone expression that the null cell adenomas. These results indicate that clinically nonfunctioning pituitary adenomas produce hormones, even though blood hormone levels are normal or low. Furthermore, the evidence of multihormonal production implies that two or more cell lineages including a protein hormone-producing type and a glycoprotein hormone-producing type may exist in the same nonfunctioning pituitary adenoma.

Coordinated transitions in neurotransmitter systems for the initiation and propagation of spontaneous retinal waves

Spontaneous waves of excitation in the developing mammalian retina are mediated, to a large extent, by neurotransmission. However, it is unclear how the underlying neurotransmitter systems interact with each other to play specific roles in the formation of retinal waves at various developmental stages. In particular, it is puzzling why the waves maintain a similar propagation pattern even after underlying neurotransmitter systems have undergone drastic developmental changes. Using Ca(2+) imaging and patch clamp in a whole-mount preparation of the developing rabbit retina, we discovered two dramatic and coordinated transitions in the excitatory drive for retinal waves: one from a nicotinic to a muscarinic system, and the other from a fast cholinergic to a fast glutamatergic input. Retinal waves before the age of postnatal day 1 (P1) were blocked by nicotinic antagonists, but not by muscarinic or glutamatergic antagonists. After P3, however, the spontaneous wave, whose basic spatiotemporal pattern remained similar, was completely inhibited by muscarinic or glutamate antagonists, but not by nicotinic antagonists. We also found that the muscarinic drive, mediated primarily by M1 and M3 receptors, was particularly important for wave propagation, whereas the glutamatergic drive seemed more important for local excitation. Our results suggest (1) a novel mechanism by which a neurotransmitter system changes its functional role via a switch between two completely different classes of receptors for the same transmitter, (2) the cholinergic system plays a critical role in not only early but also late spontaneous waves, and (3) the continued participation of the cholinergic system may provide a network basis for the consistency in the overall propagation pattern of spontaneous retinal waves.

Proteolytic cleavage of beta(2)-glycoprotein I: reduction of antigenicity and the structural relationship

Binding of beta(2)-glycoprotein I (beta(2)-GPI)-dependent anticardiolipin antibodies (aCL) derived from antiphospholipid syndrome (APS) is significantly reduced in aCL ELISA due to loss of the phospholipid (PL) binding property of beta(2)-GPI by plasmin treatment. In the present study, the treatment generated a nicked form of beta(2)-GPI and resulted in loss of antigenicity for the autoantibodies detected in ELISA, using an beta(2)-GPI directly adsorbed polyoxygenated carboxylated plate, the assay system of which was not related to PL binding. The nicked form bound to neither Cu(2+)-oxidized low-density lipoprotein (oxLDL) nor to beta(2)-GPI-specific lipid ligands isolated from oxLDL, the result being a complete loss of subsequent binding of anti-beta(2)-GPI autoantibodies. The conformational change in the nicked domain V was predicted from its intact structure determined by an X-ray analysis (implemented in Protein Data Bank: 1C1Z), molecular modeling and epitope mapping of a monoclonal anti-beta(2)-GPI antibody, i.e. Cof-18, which recognizes the related structure. The analysis revealed that novel hydrophobic and electrostatic interactions appeared in domain V after the cleavage, thereby affecting the PL binding of beta(2)-GPI. Such a conformational change may have important implications for exposure of cryptic epitopes located in the domains such as domain IV.

Taxane diterpenoids from Taxus yunnanensis and Taxus cuspidata

Chemical examination of the seeds of the Chinese yew, Taxus runnanensis Cheng et L. K. Fu and the Japanese yew, Taxus cuspidata Sieb et Zucc, resulted in the isolation of four taxane diterpenoids. The structures of these taxoids were established as (12alpha)-2alpha-acetoxy-5alpha,9alpha, 10beta-trihydroxy-3,11-cyclotax-4(20)-en-13-one; 2alpha,7beta,13alpha-triacetoxy-5alpha, 9alpha-dihydroxy-2(3-->20)abeotaxa-4(20),11-dien-10-one; 9alpha,10beta-diacetoxy-5alpha-cinnamoyloxytaxa- 4(20),11-dien-13alpha-ol and the known 2alpha,7beta,9alpha,10beta,13-pentaacetoxytax a-4(20),12-diene-5alpha,11beta-diol on the basis of spectral analysis.

[Remodelling of the spinal canal after thoracolumbar burst fractures: significance of nonoperative management]

OBJECTIVES

To determine the phenomenon of remodelling of the spinal canal after thoracolumbar burst fracture and to investigate the efficacy of nonoperative management.

METHODS

A total of 31 patients with thoracolumbar burst fractures, including 7 untreated, 16 treated nonoperatively, and 8 treated operatively, were retrospectively analysed and followed up for 3 to 7 year. The initial and final degrees of neurological deficit and stenotic ratio of the spinal canal were recorded.

RESULTS

The stenotic ratio significantly decreased (P < 0.01) from the discharge (range: 12.3% to 74.5%, average: 26.2%) to the final follow-up (range: 5.4% to 46.5%, average: 19.2%), but there were no differences (P > 0.05) of stenotic ratio improvement among the patients untreated, and treated nonoperatively and operatively, or among the patients with different degree of neurological deficit.

CONCLUSIONS

Significant remodelling of the spinal canal develops after thoracolumbar burst fractures. Nonoperative management may be taken into account for treatment of neurological intact patients with thoracolumbar burst fractures.

[Study on vitamin E succinate inducing apoptosis of human gastric carcinoma cell]

The effects of vitamin E succinate (VES) on the growth of human gastric carcinoma SGC-7901 cell were observed in cell culture. The apoptosis of SGC-7901 cell induced by VES was studied by fluorescent staining and flow-cytometry. The results showed that VES (5, 10 and 20 mg/L) could obviously inhibit the growth of gastric carcinoma cell, and it could be the result of inducing apoptosis.

Dynamics of non-structural carbohydrates in developing leaves, bracts and floral buds of cotton

Development of cotton (Gossypium hirsutum L.) squares (i.e. floral buds with bracts) is fundamental for yield formation. A 2-year field study was conducted to determine dry weight (DW) accumulations of cotton leaves, floral bracts and floral buds, and the changes in concentrations of non-structural carbohydrates (hexoses, sucrose and starch) in these tissues during square ontogeny as affected by fruiting positions within the plant canopy. During square development, DW accumulation of a subtending sympodial leaf and floral bracts followed a sigmoid growth curve with increasing square age, whereas the DW increase of a floral bud followed an exponential curve. Main-stem node (Node 8, 10 or 12) and branch position (proximal vs. distal) within a plant canopy significantly affected DW accumulations of the leaf, bracts and floral bud. Starch was the dominant non-structural carbohydrate in the three tissues, accounting for more than 65% of total non-structural carbohydrates (TNC). Subtending leaf TNC increased as square age increased. The bracts exhibited a smaller change in TNC than leaves. Non-structural carbohydrate concentration was the lowest in 10-day-old floral buds, and had little change during the first 15 days of square development. Within 5 days prior to anthesis, the floral-bud TNC increased dramatically, tripling at the time of floral anthesis compared with 15-day-old floral buds. Square age and fruiting position significantly affected non-structural carbohydrate concentrations of subtending leaves, bracts, and floral buds. The correlation did not exist between final boll retention and non-structural carbohydrate concentrations of floral buds at different fruiting positions under normal growth conditions. The pattern of floral-bud non-structural carbohydrates during square ontogeny suggests that major events in carbohydrate metabolism occur just prior to anthesis.

[Inhibition of human gastric carcinoma cell growth by vitamin E succinate]

The effects of vitamin E succinate (VES) on the growth of human gastric carcinoma cell (SGC-7901) were examined and compared with the effects of alpha-tocopherol by MTT assay. It was found that VES(5, 10 and 20 micrograms/ml) inhibited cell growth significantly, but alpha-tocopherol did not show any inhibition effects. The results showed that the anticancer effect of VES and the anticancer mechanism of VES is different from alpha-tocopherol.

Structure and stability effects of the mutation of glycine 34 to serine in Rhodobacter capsulatus cytochrome c(2)

Gly 34 and the adjacent Pro 35 of Rhodobacter capsulatus cytochrome c(2) (or Gly 29 and Pro 30 in vertebrate cytochrome c) are highly conserved side chains among the class I c-type cytochromes. The mutation of Gly 34 to Ser in Rb. capsulatus cytochrome c(2) has been characterized in terms of physicochemical properties and NMR in both redox states. A comparison of the wild-type cytochrome c(2), the G34S mutation, and the P35A mutation is presented in the context of differences in chemical shifts, the differences in NOE patterns, and structural changes resulting from oxidation of the reduced cytochrome. G34S is substantially destabilized relative to wild-type (2.2 kcal/mol in the oxidized state) but similarly destabilized relative to P35A. Nevertheless, differences in terms of the impact of the mutations on specific structural regions are found when comparing G34S and P35A. Although available data indicates that the overall secondary structure of G34S and wild-type cytochrome c(2) are similar, a number of both perturbations of hydrogen bond networks and interactions with internal waters are found. Thus, the impact of the mutation at position 35 is propagated throughout the cytochrome but with alterations at defined sites within the molecule. Interestingly, we find that the substitution of serine at position 34 results in a perturbation of the heme beta meso and the methyl-5 protons. This suggests that the hydroxyl and beta carbon are positioned away from the solvent and toward the heme. This has the consequence of preferentially stabilizing the oxidized state in G34S, thus, altering hydrogen bond networks which involve the heme propionate, internal waters, and key amino acid side chains. The results presented provide important new insights into the stability and solution structure of the cytochrome c(2).

Three new taxoids from the seeds of Japanese yew, Taxus cuspidata

Five taxane diterpenoids were isolated from the seeds of the Japanese yew, Taxus cuspidata Sieb. et Zucc. The structures were established as 2 alpha,7 beta,13 alpha-triacetoxy-5 alpha-(3'-dimethylamino-3'-phenyl)-propionyloxy-2(3-->20)-aboe+ ++-taxa-9,10-dione (1) and 2 alpha,7 beta,9 alpha,10 beta-tetraacetoxy-5 alpha-[(2R,3S),N,N-dimethyl-3-phenylisoseryloxy]-taxa-4(20),11- dien-13-one (2), 2 alpha, 9 alpha, 10 beta-triacetoxy-5 alpha-cinnamoxy-taxa-4(20),11-diene-13 alpha-ol (3), taxezopidine J (4), and taxuspine D (5) on the basis of 1D, 2D NMR, and MS spectral analysis. Compounds 1, 2, and 3 are new compounds.

New taxane diterpenoid from seed of the Chinese yew, Taxus yunnanensis

A novel taxane diterpenoid with a rearranged 5/7/6-membered ring system was isolated from seeds of the Chinese yew, Taxus yunnanensis. Its structure was established as 9alpha,13alpha-diacetoxy-10beta-benzoxy-5alpha- cinnamoyl-11(1 5-->1)-abeotaxa-4(20),11-dien-15-ol on the basis of a spectroscopic analysis. Its relative stereochemistry is proposed from the results of NOESY experiments.

Changes in phospholipase D isoform activity and expression in multidrug-resistant human cancer cells

Multidrug resistance (MDR) is a major cause of failure of cancer chemotherapy and is often associated with elevated expression of drug transporters such as P-glycoprotein (P-gp) in the cancer cells. MDR is, however, accompanied by additional biochemical changes including modifications of membrane composition and properties. We have shown that MDR is associated with a massive up-regulation of caveolin expression and an elevated surface density of caveolae. We report that phospholipase D (PLD), a constituent enzyme of caveolae and detergent-insoluble glycolipid-rich membranes (DIGs), is up-regulated in human MDR cancer cells. Lysates of HT-29-MDR human colon adenocarcinoma cells, MCF-7 AdrR human breast adenocarcinoma cells and the corresponding parental drug-sensitive cells, were fractionated on discontinuous sucrose density gradients. PLD activity was found to be enriched in low density fractions that contain DIGs and caveolar membranes, and the activity in these fractions was 4- to 6-fold higher in the MDR cells compared with the parental drug- sensitive cells. Utilizing specific antibodies to PLD1 and PLD2, the distribution of PLD isoforms along the gradient was determined and the PLD localized in DIGs and caveolar membranes has been identified as PLD2. Northern blot analysis of PLD1 and PLD2 mRNA levels has indicated that PLD2 mRNA is elevated in both HT-29-MDR and MCF-7 AdrR cells. PLD1 mRNA levels were either unchanged or reduced in the MDR cells. Finally, in vivo experiments have confirmed previous results showing that activation of PLD by phorbol esters is markedly potentiated in the MDR cells. We conclude that MDR is accompanied by an increase in PLD2 activity in DIGs and caveolar membranes.

A Na+/Ca2+ exchanger inhibitor, KB-R7943, caused negative inotropic responses and negative followed by positive chronotropic responses in isolated, blood-perfused dog heart preparations

Effects of a Na+/Ca2+ exchanger inhibitor, KB-R7943 (2-[2-[4-(4-nitrobenzyloxy)phenyl]ethyl] isothiourea methanesulfonate), on the sinoatrial nodal pacemaker activity, atrial contractility and ventricular contractility were investigated in the isolated and blood-perfused right atrium and left ventricle of the dog. KB-R7943 (0.03- 3 micromol) induced negative inotropic effects and negative followed by positive chronotropic effects in the right atrium and negative inotropic effects in the left ventricle. Neither atropine nor hexamethonium affected the cardiac responses to KB-R7943. Propranolol attenuated the positive chronotropic response to KB-R7943 but imipramine did not. Tetrodotoxin potentiated the positive chronotropic response to KB-R7943 in 6 of 11 isolated atria. When NaCl infusion increased atrial contractile force and atrial rate, KB-R7943-induced negative inotropic and chronotropic responses were attenuated in a dose-dependent manner. CaCl2 infusion potentiated the negative chronotropic response to KB-R7943 but did not affect the inotropic response significantly. On the other hand, ouabain (17 nmol) attenuated the negative inotropic response, but not chronotropic response, to KB-R7943. These results suggest that KB-R7943-induced cardiac effects relate to the Na+ activity, probably mediated through the Na+/Ca2+ exchanger, and the Na+/Ca2+ exchanger modifies the pacemaker activity and myocardial contractility in the dog heart.

Three new taxane diterpenoids from seeds of the Chinese yew, Taxus yunnanensis and T. chinensis var. mairei

Three new taxane diterpenoids were isolated from the seeds of the Chinese yew, Taxus yunnanensis Cheng et L. K. Fu and T. chinensis var. mairei Cheng et L. K. Fu. The structures were established as 1beta,10beta-dihydroxy-9alpha,13alpha-diacetoxy-5alpha-(3'-dimethylamino-3'-phenyl)-propionyloxytaxa-4(20),11-diene, 5alpha-hydroxy-9alpha,100,13alpha-triacetoxy-11(15-->1)abeotaxa-4(20),11-di-ene, and 5alpha,13alpha-dihydroxy-9alpha,10beta-diacetoxy-11 (15-->1 )abeo-taxa-4(20),11-diene on the basis of 1D, 2D NMR, and mass spectral analysis.

Upregulation of heme oxygenase-1 protects genetically fat Zucker rat livers from ischemia/reperfusion injury

We examined the effects of upregulation of heme oxygenase-1 (HO-1) in steatotic rat liver models of ex vivo cold ischemia/reperfusion (I/R) injury. In the model of ischemia/isolated perfusion, treatment of genetically obese Zucker rats with the HO-1 inducer cobalt protoporphyrin (CoPP) or with adenoviral HO-1 (Ad-HO-1) significantly improved portal venous blood flow, increased bile production, and decreased hepatocyte injury. Unlike in untreated rats or those pretreated with the HO-1 inhibitor zinc protoporphyrin (ZnPP), upregulation of HO-1 by Western blots correlated with amelioration of histologic features of I/R injury. Adjunctive infusion of ZnPP abrogated the beneficial effects of Ad-HO-1 gene transfer, documenting the direct involvement of HO-1 in protection against I/R injury. Following cold ischemia/isotransplantation, HO-1 overexpression extended animal survival from 40% in untreated controls to about 80% after CoPP or Ad-HO-1 therapy. This effect correlated with preserved hepatic architecture, improved liver function, and depressed infiltration by T cells and macrophages. Hence, CoPP- or gene therapy-induced HO-1 prevented I/R injury in steatotic rat livers. These findings provide the rationale for refined new treatments that should increase the supply of usable donor livers and ultimately improve the overall success of liver transplantation.

Misexpression of argos, an inhibitor of EGFR signaling in oogenesis, leads to the production of bicephalic, ventralized, and lateralized Drosophila melanogaster eggs

Epidermal growth factor receptor (EGFR) signaling pathways are frequently involved in generating cell fate diversity in a number of organisms. During anterior-posterior and dorso-ventral polarity in the Drosophila egg chamber and eggshell, EGFR signaling leads to a number of determinative events in the follicle cell layer. A high level of Gurken signal leads to the expression of argos in dorsal midline cells. Lateral follicle cells, receiving a lower level of Gurken signal, can continue to express the Broad-Complex (BR-C) and differentiate into cells which produce chorionic appendages. Misexpression of argos in mid-oogenesis causes the midline cells to retain expression of BR-C, resulting in a single fused large appendage. Evidence that argos can directly repress Gurken-induced EGFR signaling is seen when premature expression of argos is induced earlier in oogenesis. It represses the Gurken signal at stage 5-6 of oogenesis which determines posterior follicle cells and occasionally leads to eggs with anteriors at both ends. We propose that the Gurken signal at stage 9 of oogenesis induces follicle cells to take on two fates, dorsal midline and lateral, each producing different parts of the eggshell and that argos is one of the key downstream genes required to select between these two fates.

Crystal structure of colicin E3 immunity protein: an inhibitor of a ribosome-inactivating RNase

BACKGROUND

Colicins are antibiotic-like proteins of Escherichia coli that kill related strains. Colicin E3 acts as an RNase that specifically cleaves 16S rRNA, thereby inactivating the ribosomes in the infected cell. The producing organism is protected against colicin E3 by a specific inhibitor, the immunity protein Im3, which forms a tight 1:1 complex with colicin E3 and renders it inactive. Crystallographic studies on colicin E3 and Im3 have been undertaken to unravel the structural basis for the ribonucleolytic activity and its inhibition.

RESULTS

The crystal structure of Im3 has been determined to a resolution of 1.8 A. The structure consists of a four-standard antiparallel beta sheet flanked by three alpha helices on one side of the sheet. Thr7, Phe9, Phe16 and Phe74 form a hydrophobic cluster on the surface of the protein in the vicinity of Cys47. This cluster is part of a putative binding pocket which also includes nine polar residues.

CONCLUSIONS

The putative binding pocket of Im3 is the probable site of interaction with colicin E3. The six acidic residues in the pocket may interact with some of the numerous basic residues of colicin E3. The involvement of hydrophobic moieties in the binding is consistent with the observation that the tight complex can only be dissociated by denaturation. The structure of Im3 resembles those of certain nucleic acid binding proteins, in particular domain II of topoisomerase I and RNA-binding proteins that contain the ribonucleoprotein (RNP) sequence motif. This observation suggests that Im3 has a nucleic acid binding function in addition to binding colicin E3.

A comparative study on the treatment of migraine headache with combined distant and local acupuncture points versus conventional drug therapy

According to Chinese medicine, the differential diagnosis of migraine headache may be classified based on the state of the viscera, channels and collaterals. In this study, acupuncture treatment prescriptions combining distant and local acupoints were selected according to the differential diagnosis. Sixty-four patients were divided into two equal groups: one group received acupuncture, and the other group underwent conventional drug treatment.

RESULTS

The efficacy rates in the acupuncture and control groups were as follows, respectively: Cure: 75% versus 34.4%, marked improvement: 18.8% versus 28.1%, no effect: 6.3% versus 37.5%. The overall effective rates for the acupuncture and control groups were 93.8% and 62.5%, respectively, indicating a significantly greater effect in the acupuncture group (P < 0.01, x = 13.475).

Effects of some factors on callus growth and flavonoids formation in callus cultures of Saussurea medusa

The effects of some physical and chemical factors on callus growth and flavonoids formation in callus cultures of Saussurea medusa Maxim were studied. The optimal temperature for callus growth and flavonoids formation were 25 degrees C. Flavonoids formation were greatly inhibited under dark condition, and stimulated by white light. Callus growth was promoted when 1 mg/L NAA and 0.2 mg/L KT were added to the media. The combination of 5% sucrose and 1% glucose was useful for callus growth and flavonoids formation. A fine callus strain of S.medusa was selected through irradiation with 4000 Gy of gamma-ray. The growth rate and flavonoids content of the callus strain were high and stable. Sensitive and rapid methods of high-performance liquid chromatography as well as UV spectrophotometry were developed for detecting the flavonoids in cultured cells. The results revealed that the content of total flavonoids in dry cells under white light condition was 3.2%, 4.4 times more than under dark condition and the control of flavonoids in dry cell culture at 25 degrees C was 2.02% which was 5 and 3.2 times more than those cultured at 20 degrees C and 35 degrees C respectively.

The ASK1 gene regulates development and interacts with the UFO gene to control floral organ identity in Arabidopsis

Normal flower development likely requires both specific and general regulators. We have isolated an Arabidopsis mutant ask1-1 (for -Arabidopsis skp1-like1-1), which exhibits defects in both vegetative and reproductive development. In the ask1-1mutant, rosette leaf growth is reduced, resulting in smaller than normal rosette leaves, and internodes in the floral stem are shorter than normal. Examination of cell sizes in these organs indicates that cell expansion is normal in the mutant, but cell number is reduced. In the mutant, the numbers of petals and stamens are reduced, and many flowers have one or more petals with a reduced size. In addition, all mutant flowers have short stamen filaments. Furthermore, petal/stamen chimeric organs are found in many flowers. These results indicate that the ASK1 gene affects the size of vegetative and floral organs. The ask1 floral phenotype resembles somewhat that of the Arabidopsis ufo mutants in that both genes affect whorls 2 and 3. We therefore tested for possible interactions between ASK1 and UFO by analyzing the phenotypes of ufo-2 ask1-1 double mutant plants. In these plants, vegetative development is similar to that of the ask1-1 single mutant, whereas the floral defects are more severe than those in either single mutant. Interior to the first whorl, the double mutant flowers have more sepals or sepal-like organs than are found in ufo-2, and less petals than ask1-1. Our results suggest that ASK1 interacts with UFO to control floral organ identity in whorls 2 and 3. This is very intriguing because ASK1 is very similar in sequence to the yeast SKP1 protein and UFO contains an F-box, a motif known to interact with SKP1 in yeast. Although the precise mechanism of ASK1 and UFO action is unknown, our results support the hypothesis that these two proteins physically interact in vivo.

[Study on proteins of allele by using the microisoelectric focusing]

Clear protein electrophoresis pattern of single pollen grain from Cucurbita pepo L. was obtained with isoelectric focusing and supersensitive stain technique. The results showed that there were two special distributing protein bands near acidity pole. In species I, the two protein bands were a little near to acidity pole and in species II, that was a little far from acidity pole. In species III, the two protein bands distributed either like species I or like species II and the distributed ratio was 1:1. Moreover, we discuss how to identify relative purity of gene with the sorts of the special proteins.