Natural Occurrence of Chilli veinal mottle virus on Capsicum chinense in China

An outbreak of a viral disease on chili pepper (Capsicum chinense Jacp. cv. Yellow Lantern) occurred in Hainan Province, China during 2003 and 2004. The disease was prevalent in five chili-producing counties surveyed. Leaves of infected plants initially displayed symptoms of dark green banding along veins and later became distorted with striking mosaic. Infected plants had reduced flower numbers and fruit set, resulting in a significant yield loss. The causative virus was characterized and identified as Chilli veinal mottle virus (ChiVMV) (3). An isolate of the virus was obtained via three single lesion passages through Chenopodium amaranticolor and was shown to reproduce the same symptoms on inoculated C. chinense cv. Yellow Lantern. Negative staining of crude extracts of the infected tissue and subsequent electron microscopy revealed flexuous rods of 12 to 13 × 750 nm, typical of a potyvirus. Pinwheel-like inclusion bodies were abundant in thin sections of infected leaves. Purified virus preparations contained one major protein of 32.8 kDa and one minor protein of 28 kDa when fractionated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Both of these protein bands were excised and subsequently analyzed using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). Multiple peptide fragments from both proteins were identified as arising from ChiVMV capsid protein (CP) (1,2). Therefore, the 32.8-kDa protein is the full-length ChiVMV CP and the 28-kDa protein is presumably a degradation product of the CP. The combined biological and molecular data provided strong evidence that the viral disease on C. chinense was caused by ChiVMV. To our knowledge, this is the first report of ChiVMV infection on C. chinense in China and the first report of C. amaranticolor as an experimental host for ChiVMV. References: (1) P. Chiemsombat et al. Arch. Virol. 143:1855, 1998. (2). J. Joseph and H. S. Savithri. Arch. Virol. 144:1679, 1999. (3) P. Siriwong et al. Plant Pathol. 44:718, 1995.

BACH1 is a DNA repair protein supporting BRCA1 damage response

The link between defects in BRCA1 and breast cancer development may be best understood by deciphering the role of associated proteins. BRCA1 associated C-terminal helicase (BACH1) interacts directly with the BRCA1 C-terminal BRCT repeats, which are important for BRCA1 DNA repair and are mutated in the majority of BRCA1 familial cancers. Thus, BACH1 is a likely candidate for mediating BRCA1 DNA repair and tumor suppression functions. Although previous evidence using overexpression of a dominant negative BACH1 has suggested that BACH1 is involved in BRCA1-DNA repair function, our results using BACH1 deficient cells provide direct evidence for involvement of BACH1 in DNA repair as well as for localizing BRCA1. Following DNA damage BACH1 is modified by phosphorylation, displays a BRCA1-like nuclear foci pattern and colocalizes with gamma-H2AX. Given that the BACH1/BRCA1 complex is unaltered by DNA damage and the intensity of BRCA1 foci is diminished in BACH1 deficient cells, BACH1 may serve to not only facilitate DNA repair, but also maintain BRCA1 in DNA damage foci.

Nitrate removal from drinking water through the use of encapsulated microorganisms in alginate beads

Biological treatment for removal of nitrate from drinking water is of great significance, as traditional physical and chemical methods could not effectively remove soluble nitrate. In this report immobilized microorganisms with co-immobilized calcium tartrate were used for reducing nitrate concentration (110 mg l(-1) NO3-N) in a model solution. The carbon source also functions as a stabilizing agent for the immobilization matrix. Experiments of denitrification showed a high nitrate removal rate while nitrite residual was at a concentration higher than expected. The nitrate concentration was reduced to nearly zero (0.2-1.4 mg l(-1)) after 3 days of operation. The calcium tartrate (4%, w/w) co-immobilized alginate beads had better nitrate removal performance than tartrate in solution. The nitrite-N residual concentration was approximately 1.1-2.9 mg l(-1) at the end of the experiments, showing the desirability of further denitrification. The stability of alginate beads was also tested both to evaluate their behaviors and investigate the efficacy of bead recycling. It was found that the beads could be used for 8-13 days consecutively without any structural deterioration and leaking of microbes.

[A study of bone development and metabolism in childhood]

OBJECTIVE

To explore the regularity of bone development and metabolism in childhood.

METHODS

A survey was made to collect and analyze the data on bone biochemistry, the density of lumbar vertebrae and the X-ray examination of calcaneus in 224 healthy children aged 3-15 years in the urban area of Chengdu.

RESULTS

Comparative analysis of serum and urine calcium and phosphate concentrations showed no significant difference between the age groups. The serum alkaline phosphatase (ALP) and bone alkaline phosphatase (BALP) were found to increase with age and reach their peak values in children aged 7-12 years, and their values were significantly higher than that of adults (P < 0.05). The density of lumbar vertebrae and the trabecular bone of calcanesus also developed with age.

CONCLUSION

The measurements of the bone biochemistry, bone density and the trabecular bone of calcaneus which reflect the bone development and metabolism have their special regularity in childhood. The criteria in use for adulthood is not fit for the evaluation in childhood. The data obtained can be used in clinical diagnosis and treatment of the bone metabolic diseases of children.

Localization of the mouse kidney disease (kd) gene to a YAC/BAC contig on Chromosome 10

Mice that are homozygous for the kidney disease (kd) gene on Chromosome (Chr) 10 spontaneously develop a progressive and fatal interstitial nephritis. The disease phenotype is similar to that of the human disease, juvenile nephronophthisis. Using a backcross and intercross breeding strategy and analysis of over 900 resultant progeny, this genetic locus has now been mapped to a minimal co-segregating region of approximately two megabases between D10Mit 193 and D10Mit 38. The location assigned to kd by this study is over 3 cM from the current Mouse Genome Database location. The entire interval has been cloned in yeast artificial chromosome (YAC) and bacterial artificial chromosome (BAC) clones. Recombinant analysis has permitted assignment of 13 Mit microsatellite markers to positions near or within the region. Two new markers have been identified by using single-strand conformation polymorphism (SSCP) analysis of sequenced BAC ends. Several BAC end sequences align with human BAC clones from Chr 6q2 that contain NR2E1. Snx3, and Ros1. Three murine genes, CD24a, fyn, and ColX reported to map in or near the kd region as defined by this study have been evaluated. Though not definitely excluded, they appear to be unlikely candidates.

The vomeronasal organ is involved in discrimination of individual odors by males but not by females in golden hamsters

The vomeronasal organ (VNO) has a wide variety of functions in terrestrial vertebrates, some of which involve responses to classical pheromones whereas others do not. We examined the role of the VNO in discrimination of individual differences in odors of male and female golden hamsters using a habituation paradigm. Removal of the VNO resulted in elimination of the ability of male hamsters to discriminate between some individually distinctive odors (e.g., flank gland secretion), but not others (e.g., urine). In females, such lesions had no effect. The type of test trial also influenced the results; in test trials employing a single, novel odor, removal of the VNO in males did have an effect but in test trials in which both the novel and the familiar odor were presented, VNO removal had no effect. It is concluded that (a) there is a sex difference in the role of the VNO in the discrimination of individual odors, (b) the role of the VNO in discrimination of individual odors varies from odor to odor, and (c) deficits due to VNO removal are more readily observed in more difficult tasks.

Starch-branching enzymes preferentially associated with A-type starch granules in wheat endosperm

Two starch granule-bound proteins (SGP), SGP-140 and SGP-145, were preferentially associated with A-type starch granules (>10 microm) in developing and mature wheat (Triticum aestivum) kernels. Immunoblotting and N-terminal sequencing suggested that the two proteins were different variants of SBEIc, a 152-kD isoform of wheat starch-branching enzyme. Both SGP-140 and SGP-145 were localized to the endosperm starch granules but were not found in the endosperm soluble fraction or pericarp starch granules younger than 15 d post anthesis (DPA). Small-size starch granules (<10 microm) initiated before 15 DPA incorporated SGP-140 and SGP-145 throughout endosperm development and grew into full-size A-type starch granules (>10 microm). In contrast, small-size starch granules harvested after 15 DPA contained only low amounts of SGP-140 and SGP-145 and developed mainly into B-type starch granules (<10 microm). Polypeptides of similar mass and immunologically related to SGP-140 and/or SGP-145 were also preferentially incorporated into A-type starch granules of barley (Hordeum vulgare), rye (Secale cereale), and triticale (x Triticosecale Wittmack) endosperm, which like wheat endosperm have a bimodal starch granule size distribution.

[Immobilization osteoporosis and fracture in children]

This study was intended to enhance the diagnostic vigilance of immobilization osteoporosis with fracture and explore its prevention and treatment. Thirteen children with the hip disease underwent one to nine months of plaster cast after operation. A retrospective analysis was made on these 13 patients with fracture and immobilization osteoporosis. The result showed that disuse fracture occurred in fifteen places of their femora. All of these cases were cured by non-operative and drug treatment. These data suggest that for the cases of immobilization osteoporosis it is important to prevent fracture by means of early diagnosis, proper drugs, early function exercise, appropriately shorter period of fixation and the avoidance of trauma.

External quality assessment survey for hematological laboratories in China

To evaluate the feasibility of improving external quality assessment (EQA), we set up an experimental EQA survey that included 465 participants in China. During the period of this survey, we checked the quality of the EQA samples, divided the participants into different groups, each laboratory's result was assessed by calculation standard deviation index (SDI). The reference values were determined to evaluate the accuracy for peer groups. The data showed that the stability of the EQA samples was acceptable. Except for WBC count of the Abbott group, the mean, median and reference values for each parameter were very close. We found that the main reason affecting the performance of the participants was not using the reagents. calibrator and QC material recommended by manufacturer. From this survey, we obtain a good reference for future improvement.

Anatomical study of the synovial plicae of the hip joint

Observations and measurements of the synovial plicae of the hip joints were made on 63 embalmed cadavers. The cadavers were divided equally among three age groups (fetuses, children, and adults). Our observations showed that the plicae appeared in two forms (flat and villous) and were mainly confined to the external surface of the lower medial part of the acetabular labrum (labral plicae), the base of the ligament of the head of the femur (ligamental plicae), and along the reflecting line of the synovial membrane on the base of the femoral neck (neck plicae). The ligamental plicae were well padded with a fibroelastic pad of fat filling the acetabular fossa, and the neck plicae were far away from the articular surfaces of the joint; as a result, neither was likely to be injured or entrapped during joint movements. The labral plicae were larger than the ligamental or neck plicae and had an incidence of 73.8% in the fetal group. The fetal plicae were found only after the fetal age of 5 months. In nine cases of the child and adult groups, the labral plicae extended between the articular surface of the femoral head and the lower part of the acetabulum during medial rotation of the thigh. When the thigh was rotated laterally, the plicae in six of the same cases could be returned to their original positions. In the remaining three cases, there was continual impingement.

[Coordination and local structure of Si and Al in silicate glasses and melts: X-ray absorption spectroscopic study]

The coordination and local structure of Si and Al in silicate glasses and melts have been studied using Si and Al K-edge X-ray absorption spectroscopy for the first time. It has been verified that in SiO2-P2O5 and Na2O-SiO2-P2O5 join phosphate silicate glasses, Si atoms remains tetrahedrally coordinated with oxygen when the content of P2O5 is below 32 mol%, but partial Si atoms become octahedrally coordinated with oxygen when the content of P2O5 increases above 32 mol%, and the proportion of the octahedrally coordinated Si atoms increases with the increasing content of P2O5. It has also been demonstrated that Al remains four-fold coordinated with oxygen in ambient NaAlSi2O6-NaAlSi3O8 glasses, but in the same composition glasses quenched at 4.4 GPa and 1,575 degrees C, partial Al atoms becomes five- and six-fold coordinated with oxygen, and at the same pressure and temperature, the proportions of five- and six-fold coordinated Al atoms increases with the increasing content of NaAlSi2O6 in the glasses. Thus, the pressure-induced coordination change of Al in aluminosilicate glasses and melts has been observed for the first time by Al K-edge X-ray absorption spectroscopy.

Induction of Th1 response by dendritic cells pulsed with autologous melanoma apoptotic bodies

BACKGROUND

We hypothesize that dendritic cells (DCs) can process antigens from autologous melanoma apoptotic bodies (MABs) and induce effector T cells in melanoma patients.

MATERIALS AND METHODS

Peripheral blood mononuclear cells were obtained from three stage IV melanoma patients and adherent cells were cultured in complete medium (CM) containing GM-CSF (800 U/ml) and IL-4 (1000 U/ml) for 7 days. Autologous MABs from melanoma cells following actinomycin D treatment (0.5 microgram/ml) for 24 hours, were added to 72 hour DC culture. Autologous effector T cells were cultured in CM containing 60 IU/ml of IL-2 and were stimulated by MAB-pulsed DCs three times at a weekly interval. Effector T cells were harvested at the end of third cycle of DC stimulation.

RESULTS

Using ELISPOT, IFN-gamma production by effector T cells stimulated by MAB-pulsed DCs was significantly higher than that by T cells without DC stimulation. Microscopy demonstrated phagocytosis of MABs by DCs.

CONCLUSIONS

MAB-pulsed DCs are capable of stimulating Th1-directed autologous effector T cells. Pulsing DCs with autologous MABs may be a novel approach in future DC-based immunotherapeutic trials.

The direction of microsatellite mutations is dependent upon allele length

Microsatellites, comprising tandemly repeated short nucleotide sequences, are ubiquitous in eukaryotic genomes. Mutations within microsatellites are frequent, altering their overall length by insertion or deletion of a small number of repeat units, with a rate as high as 10(-3) in humans. Despite their high mutability, stable allele frequency distributions are typically observed for microsatellites in humans as well as other primates, although the mechanism maintaining these stable distributions remains unclear. Previous studies have suggested that microsatellite mutations occur more frequently in longer alleles and favour expansion. Generalizing these results has been hindered because the sample sizes were small, only a small subset of alleles for any marker was studied and the direction of mutation (expansion or contraction) was not rigorously determined. Here we examine 236 mutations at 122 tetranucleotide repeat markers and find that the rate of contraction mutations increases exponentially with allele size, whereas the rate of expansion mutations is constant across the entire allele distribution. The overall rate of expansion mutations does not differ from that of contractions. Our findings offer an explanation for the stationary allele distribution of microsatellites.

The role of the hippocampal system in social odor discrimination and scent-marking in female golden hamsters (Mesocricetus auratus)

Female golden hamsters (Mesocricetus auratus) received aspiration lesions of the parahippocampal region (PARA) or electrolytic lesions of the fimbria-fornix (FNX) and were tested for their (a) discrimination between odors of individual males in a habituation-discrimination task, (b) preference for male over female odors, and (c) scent-marking in response to conspecific odors. Both lesion groups habituated to repeated presentations of a male's odor. However, only FNX females discriminated between scents of individual males, whereas PARA females did not. Neither lesion eliminated female preferences for male odors. Females with FNX lesions showed decreased levels of scent marking, but those with PARA lesions had more subtle deficits. Thus, the PARA, but not the subcortical connections of the hippocampus, is critical for discrimination of the odors of individuals.

[Determination of eight trace elements in kadsura coccinea by flame atomic absorption spectrophotometry]

In this paper, we used the flame atomic absorption spectrophotometry to determine the contents of Zn, Fe, Ca, Cu, K, Na, Mn, Mg in the kadsura coccinea. We assayed the determination conditions systematically. The SrCl2 was sued to eliminate coexisting elements. And we achieved the purpose that we can determine a lot of elements in the same liquor at the same time. It shows that this method is simple, convenient and accurate.

Perirenal lucency ("kidney sweat"): a new sign of renal failure

OBJECTIVE

This study describes a new sonographic finding in renal failure: perirenal lucency, which we call the "kidney sweat" sign.

MATERIALS AND METHODS

During 1 year at our institution, 502 renal sonograms were obtained. Sonography evaluated 330 patients with renal failure. All of the examinations were retrospectively analyzed.

RESULTS

An extracapsular hypoechoic rim was present in 47 (14%) of the 330 patients with renal failure. The finding, when present, was always bilateral. The hypoechoic rim was not present in the remaining 283 patients with renal failure. Forty (85%) of the 47 patients had kidneys that were hyperechoic compared with the liver. Twenty-eight (60%) of the 47 patients had kidneys that were hyperechoic compared with the spleen. In 15 (32%) of the 47 patients, the kidneys were small. Ascites was present in 11 (23%) of the 47 patients. Of the 283 patients with renal failure whose sonograms did not show the hypoechoic rim, 76 patients had normal sonographic findings. The remaining 207 patients with renal failure who did not show the kidney sweat sign had hydronephrosis, stones, cysts, echogenic kidneys, small kidneys, or ascites.

CONCLUSION

An extracapsular hypoechoic rim is found in patients with renal failure. We call this finding "kidney sweat." We believe, but cannot currently prove, that the kidney sweat sign represents edema. It is an additional sonographic finding in patients with renal failure.

Activation of caspase-3 in the retina of transgenic rats with the rhodopsin mutation s334ter during photoreceptor degeneration

The role of caspase-3 in photoreceptor degeneration was examined in a line of transgenic rats that carry a rhodopsin mutation S334ter. Photoreceptor degeneration in these animals is rapid. It is detected as early as postnatal day (PD) 8, and by PD 20, only one of the original 12 rows of nuclei remain in the outer nuclear layer. At PD 11 and 12, the number of photoreceptors dying per day reaches a peak of approximately 30% of the total photoreceptors in the retina. Coincident with this rapid degeneration is an increase in caspase-3-like activity as assessed by the cleavage of a fluorescent substrate N-acetyl-Asp-Glu-Val-Asp-aminomethylcoumarin and an increase in activated caspase-3 as determined by Western blot analysis for its 12 kDa subunit. Intraocular injection of an irreversible caspase-3 inhibitor N-benzyloxycarbonal-Asp(OMe)-Glu(OMe)-Val-Asp(Ome)-fluoromethyk etone partially protected photoreceptors from degeneration. These findings indicate that a caspase-3-dependent mechanism is operative in photoreceptor death in the transgenic rats under investigation.

Characterization of dendritic cells generated from peripheral blood of patients with malignant melanoma

Dendritic cells (DCs) are professional antigen presenting cells. Two x 10(7) peripheral blood mononuclear cells (PBMCs) from each of 6 melanoma patients and 4 normal donors were incubated in 6-well plates. The adherent cells were cultured in GM-CSF (800 U/ml) and IL-4 (1000 U/ml) for 10 days. Anti-CD80, anti-CD86, anti-HLA-DR, anti-HLA-class I monoclonal antibodies and supernatant from two melanoma cell lines were incubated with DCs before responder T cells were added in mixed lymphocyte reaction (MLR). The mean yields of DCs were 3.6 x 10(5) and 9.3 x 10(5) for donor and the melanoma patients respectively. MLR was inhibited by anti-CD80, anti-CD86, anti-HLA-DR, anti-HLA-Class I and supernatant of melanoma cultures. The characteristics of DCs generated from melanoma patients were comparable to those from donors. DC function was inhibited by soluble factors in melanoma cultures. Further studies are warranted to characterize these inhibitory factors.

Effects of vomeronasal organ removal on individual odor discrimination, sex-odor preference, and scent marking by female hamsters

Removal of the vomeronasal organ (VNX) did not eliminate the ability of female hamsters to discriminate between individual male's flank gland or urine odors in a habituation/discrimination task nor did it impair preference for male odors over female odors from a distance. Vomeronasal organ removal did reduce overall levels of investigation of flank gland odor in the habituation/discrimination task. Although VNX females did not show severe impairments in the frequency of either flank or vaginal marking in response to odors, they did show an abnormal pattern of marking. VNX females, unlike shams, did not flank mark more to female odors than to male odors, nor did they vaginal mark more to male odors than to female odors. Thus, the vomeronasal organ in female hamsters appears to be important for differences in scent marking toward male and female odors, but is not essential for discrimination of individual odors or for preferences for male over female odors.

Digital quantification of the enzyme-linked immunospot (ELISPOT)

Enzyme-linked immunospot (ELISPOT) is a sensitive technique for the detection of cytokines released by immune cells. The technique is well established and correlates closely with the enzyme-linked immunosorbent assay (ELISA) technique. Here, we introduce an integrated imaging-analysis system to quantitate the spots formed by the ELISPOT assay. The spots can be easily counted when the background is clear and the spots are few. However, when the number of spots increases to > 100, this task becomes challenging and time-consuming. To minimize time and standardize the counting procedure, we have used a digital camera linked to a computer system for reading the plates. In general, the computer is able to count more spots and has a smaller standard deviation when compared with the manual microscopic count. This integrated system is commercially available, and we believe that this method is objective, time-saving and consistent in routine ELISPOT assay counting, especially when numerous spots are present.

Alpha2-adrenergic agonists selectively activate extracellular signal-regulated kinases in Müller cells in vivo

PURPOSE

Alpha2-adrenergic agonists have specific and selective effects on the retina to induce expression of basic fibroblast growth factor and to protect photoreceptors. This work explores the signaling pathway that mediates these effects.

METHODS

Alpha2-adrenergic agonists xylazine and clonidine were administered systemically to male adult Sprague-Dawley rats. The activation state of extracellular signal-regulated kinases (ERKs) in the retina was assessed by immunoblot analysis, using antibodies that specifically recognize the dually phosphorylated forms of p44/p42 ERKs. Localization of phosphorylated ERKs was determined by immunocytochemistry.

RESULTS

Intramuscular injection of 6 mg/kg xylazine induced an increase in ERK phosphorylation in the retina within 30 minutes that lasted 3 hours. Xylazine induced ERK phosphorylation at 1 mg/kg and reached a maximum at 10 mg/kg. Injection of clonidine also induced ERK phosphorylation in the retina. Yohimbine, a specific alpha2-adrenergic antagonist, completely prevented the induction of ERK phosphorylation. Immunocytochemical studies showed that the increase in ERK phosphorylation occurred mainly in Müller cells. In the brain, xylazine injection resulted in a decrease in ERK phosphorylation.

CONCLUSIONS

Our results indicate that systemically administered alpha2-adrenergic agonists selectively activate ERKs in retinal Müller cells. The induced activation of ERKs in Müller cells is probably one of the early events that result in photoreceptor protection. These results also indicate that Müller cells are unique in response to alpha2-adrenergic agonists and imply a role for Müller cells in alpha2-adrenergic agonist-induced photoreceptor protection.

[Alpha1-adrenoceptor subtypes in rabbit penile corpus cavernosum]

OBJECTIVE

To study alpha(1)- adrenoceptor (alpha(1)- AR) subtypes with the functional role and the distribution of its subtypes in rabbit penile corpus cavernosum.

METHOD

The rabbit penile corpus cavernosum was studied by using functional experiment and radioligand binding assay.

RESULT

In the radioligand binding assay, the maximal binding capacity (Bmax of (125)IBE and alpha(1)-AR) decreased obviously after pretreatment with chloroethylclonidine (CEC), which were 746 +/- 236 fmol/mg protein and 214 +/- 71 fmol/mg protein, respectively. Alpha(1A)-, alpha(1D)-and alpha(1B)-AR took about 20%, 25% and 55%, respectively. In the functional experiments, the maximal contraction induced by norepinephrine (NE) was not decreased significantly after pretreatment with CEC. The pA(2) values of two alpha(1)-AR selective antagonists, 5-MU, BMY7378, for antagonizing NE-induced penile corpus cavernosum contraction had a high correlative association with the pK(I) values for cloned alpha(1A)-AR.

CONCLUSION

The functional alpha(1)-AR subtype is alpha(1A)-AR although there are three subtypes in the penile corpus cavernosum.

Expression of somatostatin receptor genes and acetylcholine receptor development in rat skeletal muscle during postnatal development

Our laboratory reported previously that somatostatin (SST) is transiently expressed in rat motoneurons during the first 14 days after birth. We investigated the possibility that the SST receptor (SSTR) is expressed in skeletal muscle. We found that two of the five subtypes of SSTR (SSTR3 and SSTR4) are expressed in skeletal muscle with a time course that correlates with the transient expression of SST in motoneurons. In addition, SSTR2A is expressed from birth to adulthood in skeletal muscle. Both SSTR2A and SSTR4 are also expressed in L6 cells, a skeletal muscle cell line. Somatostatin acting through its receptors has been shown to stimulate tyrosine phosphatase activity in a number of different tissues. We found that several proteins (50, 65, 90, 140, 180 and 200 kDa) exhibited a reduced degree of tyrosine phosphorylation following SST treatment. Inhibition of tyrosine phosphatase activity with sodium orthovanadate increased expression of the nicotinic acetyl-choline receptor (nAChR) epsilon subunit mRNA by three fold. Somatostatin reversed the elevated epsilon mRNA following orthovanadate treatment. These findings show that SSTR is expressed in skeletal muscle and that SST acting via the SSTR regulates tyrosine phosphorylation and expression of the epsilon subunit of the AChR in the rat skeletal muscle.

Angiotensin II induces diverse signal transduction pathways via both Gq and Gi proteins in liver epithelial cells

Angiotensin II stimulates a biphasic activation of Raf-1, MEK, and ERK in WB liver epithelial cells. The first peak of activity is rapid and transient and is followed by a sustained phase. Angiotensin II also causes a rapid activation of p21ras in these cells. Moreover, two Src family kinases (Fyn and Yes) were activated by angiotensin II in a time- and concentration-dependent manner. Microinjection of antibodies against Fyn and Yes blocked angiotensin II-induced DNA synthesis and c-Fos expression in WB cells, indicating an obligatory involvement of these tyrosine kinases in the activation of the ERK cascade by angiotensin II. Finally, substantial reduction of the angiotensin II-stimulated activation of Fyn, Raf-1, ERK, and expression of c-Fos by pertussis toxin pretreatment argues that G proteins of the Gi family as well as the Gq family are involved in angiotensin II-mediated mitogenic pathways in WB cells.

Ontogeny of insulin-like growth factors (IGF), IGF binding proteins, IGF receptors, and growth hormone receptor mRNA levels in porcine pancreas

We examined the ontogeny of mRNA levels of IGF-I and -II, IGF type 1 (IGFI-R) and type II receptors (IGFII-R), IGF binding protein-1 and -3 (IGFBP-1 and -3), GH receptor (GHR), and tissue concentrations of IGF and IGFBP in the pancreas of pigs. Tissues were collected from fetuses at 90 and 110 d of gestation and from pigs at 1, 21, 90 and 180 d of age. Northern blots were performed using total RNA hybridized with 32P-labeled cDNA probes (human IGF-I and human IGFI-R) and cRNA probes (rat IGF-II, human IGFII-R, human IGFBP-1, pig IGFBP-3, and pig GHR). There were two accelerated growth stages of the pancreas: the first one at 90 d of fetal life, which is characterized by cell hyperplasia (high ratio of DNA to body weight), and the second one at postnatal 90 d, which is attributed to cell hypertrophy (high ratios of pancreatic weight, RNA, and protein to DNA). The level of IGF-II mRNA and its tissue concentration were predominant during fetal life and low thereafter. The IGF-I mRNA level was high during fetal and early postnatal life and decreased thereafter. Messenger RNA levels of IGFI-R, IGFBP-3, and GHR and concentrations of IGFBP-1 and -2 were abundant during fetal and early postnatal life. In conclusion, IGF may be involved in various physiological periods of pancreatic development in pigs.

Alboaggregins A and B. Structure and interaction with human platelets

Viper venoms contain a variety of platelet binding proteins including those which bind to platelet GPIb/GPIX. Most of these proteins inhibit von Willebrand factor mediated platelet agglutination. Here we report the primary structures of unique members of this family, alboaggregins A and B, isolated from Trimeresurus albolabris, which have the ability to stimulate platelet agglutination and aggregation. Four chains of alboaggregin A and two chains of alboaggregin B share a high degree of homology and all cysteines in both alboaggregins are conserved. Both alboaggregins caused similar agglutination of fixed platelets. Alboaggregin A induced platelet aggregation and release reaction with EC50 = 10 and 30 nM, respectively, which is 20-fold lower than those for alboaggregin B. These observations suggest that the dimeric structure of alboaggregin B is sufficient to mediate its binding to GPIb and induce agglutination of platelets whereas aggregation and release reaction are significantly enhanced by tetrameric structure of alboaggregin A.

Preconditioning with bright light evokes a protective response against light damage in the rat retina

Constant exposure to bright light induces photoreceptor degeneration and at the same time upregulates the expression of several neurotrophic factors in the retina. At issue is whether the induced neurotrophic factors protect photoreceptors. We used a preconditioning paradigm to show that animals preconditioned with bright light became resistant to subsequent light damage. The preconditioning consisted of a 12-48 hr preexposure, followed by a 48 hr "rest phase" of normal cyclic lighting. The greatest protection was achieved by a 12 hr preexposure. Preconditioning induces a prolonged increase in two endogenous neurotrophic factors: basic fibroblast growth factor (bFGF) and ciliary neurotrophic factor (CNTF). It also stimulates the phosphorylation of extracellular signal-regulated protein kinases (Erks) in both photoreceptors and Müller cells. These findings indicate that exposure to bright light initiates two opposing processes: a fast degenerative process that kills photoreceptors and a relatively slower process that leads to the protection of photoreceptors. The extent of light damage, therefore, depends on the interaction of the two processes. These results also suggest a role of endogenous bFGF and CNTF in photoreceptor protection and the importance of Erk activation in photoreceptor survival.

[The experimental study of the effect of insulin and danshen on culture of fibroblast in vitro]

To investigate the effect of Insulin and Danshen on anabolism and catabolism of collagen during the healing of wound, fibroblast which was cultured from human embryonic skin were divided into 3 groups: Insulin group, Danshen group and contral group. Each group was cultured for 2, 4 and 6 days, then the growth curve was established respectively.

RESULTS

1. The growth curve showed-insulin group > control group > Danshen group. 2. The rate of cell division in 3 groups was 19.6/1000, 2.5/1000, 3.77/1000 respectively. 3. The electron microscopic scanning showed that there was much of fibroid tissue surrounding the fibroblast cell in insulin group, but there was little fibroid tissue in Danshen group. The conclusion showed that insulin can accelerates proliferation of fibroblast and synthesis of collagen, but the effect of denshen was just on the contrary.

Inhibition of thrombin-stimulated cell proliferation by ceramide is not through inhibition of extracellular signal-regulated protein kinase

Activation of the thrombin receptor provides a strong mitogenic signal in CCL39 cells. Ceramide was found to inhibit thrombin-mediated mitogenesis in these cells while dihydroceramide had no effect. Many growth inhibitors exert their effect by inhibiting extracellular signal-regulated kinase (ERK) signaling pathway. However, neither ceramide nor dihydroceramide blocked the thrombin-induced activation of ERK. In contrast, both agents potentiated ERK activity. The expression of c-fos, c-jun and cyclin D1, which are downstream of ERK in the mitogenic pathway were stimulated by thrombin but this stimulation was not affected by ceramide or dihydroceramide. Therefore, the ceramide inhibition of thrombin-stimulated cell growth in CCL39 cells does not appear to be mediated by an effect on the activation of ERK. Furthermore, the data also suggest that the separate effects of ceramide on thrombin-stimulated cell growth and ERK activity are mediated by different mechanisms.

Ontogeny of epidermal growth factor (EGF), EGF receptor (EGFR) and basic fibroblast growth factor (bFGF) mRNA levels in pancreas, liver, kidney, and skeletal muscle of pig

Epidermal growth factor (EGF), EGF receptor (EGFR), and basic fibroblast growth factor (bFGF) messenger RNA (mRNA) levels were examined by Northern blot analysis in four tissues (pancreas, liver, kidney, and skeletal muscle) of pig from fetal 90 d to postnatal 180 d of age. The present study shows for the first time that EGF mRNA increased with advancing age in the kidney and skeletal muscle of pig. A high level of EGF mRNA was observed in the kidney compared with the liver and skeletal muscle. In the pancreas, high levels of EGF mRNA were found in fetuses and newborns and were low in older pigs. Pancreatic EGFR mRNA level parallelled its EGF mRNA, whereas in the kidney and skeletal muscle, patterns of EGFR mRNA were reversed to their EGF mRNA levels. In the liver, EGFR mRNA was abundant but EGF mRNA was undetected. In the pancreas and skeletal muscle, the highest levels of bFGF mRNA were found in fetuses of 90 d of age and then decreased with advancing age. In the liver and kidney, there were no major changes in bFGF mRNA levels during the examined developmental periods. These results show that EGF, EGFR, and bFGF mRNA levels are developmentally and tissue specifically regulated in pig. In the pancreas, mRNA levels of EGF, EGFR and bFGF were high in fetal and neonatal life and low thereafter. In the kidney and skeletal muscle, EGF mRNA increased with advancing age. EGF may play a role in muscle growth and maintenance in growing pigs during the later stage of development.

Regulation of gene expression for tyrosine hydroxylase in oxygen sensitive cells by hypoxia

Carotid body type I cells and the O2 sensitive pheochromocytoma (PC12) cells release dopamine during hypoxia. Reduced O2 tension causes inhibition of an outward rectifying the O2-sensitive potassium (K) channel in the O2-sensitive pheochromocytoma (PC12) cell line, which leads to membrane depolarization and increased intracellular free Ca2+. We found that removal of Ca2+ from the extracellular milieu, inhibition of voltage-dependent Ca2+ channels, and chelation of intracellular Ca2+ prevents full activation of the TH gene expression during hypoxia. These findings suggest that membrane depolarization and regulation of intracellular free Ca2+ are critical signal transduction events that regulate expression of the TH gene in PC12 cells during hypoxia. Gene expression of tyrosine hydroxylase (TH), the rate-limiting enzyme in the biosynthesis of dopamine, is stimulated by reduced O2 tension in both type I cells and PC12 cells. The increase in TH gene expression in PC12 cells during hypoxia is due to increases in both the rate of transcription and mRNA stability. Analysis of reporter-gene constructs revealed that increased transcription of the TH gene during hypoxia is regulated by a region of the proximal promoter that extends from -284 to -150 bases, relative to the transcription start site. This region of the gene contains a number of cis-acting regulatory elements including AP1, AP2 and hypoxia-inducible factor (HIF-1). Competition assays revealed that hypoxia-induced binding occurs at both the AP1 and HIF-1 sites. Results from super-shift and shift Western assays showed that a heterodimer consisting of c-Fos and JunB binds to the AP1 site during hypoxia. Mutagenesis experiments revealed that the AP1 site is required for increased transcription of the TH gene during hypoxia. We also found that the genes that encode the c-Fos and JunB transcription factor proteins are regulated by reduced O2 tension.

Effect of weaning on epidermal growth factor and its receptor messenger RNA levels in various tissues of piglets

Weights of pancreas, liver, and stomach, and total DNA of pancreas and stomach mucosa per body weight were greater (P < 0.05) in weaned piglets than suckling ones at 30 d of age. There was no effect (P > 0.05) of weaning on epidermal growth factor (EGF) and EGF receptor (EGFR) messenger RNA levels in liver, stomach, duodenum, and skeletal muscle. Messenger RNAs of EGF in pancreas increased following weaning in piglets of 27 (P = 0.0001) and 30 (P = 0.004) d of age, indicating a possible involvement of EGF in pancreatic development during this period. Key words: Weaning, EGF, EGFR mRNA, Pig tissues

Chronic exposure of neonatal cardiac myocytes to hydrogen peroxide enhances the expression of catalase

The adaptive response of antioxidant enzymes to oxidative stress in the heart has not been investigated. Because H2O2 is considered to play a major role in reperfusion injury to the heart, this study was undertaken to examine if H2O2 alters the expression of these enzymes in the rat neonatal myocytes. H2O2 was continuously generated by the addition of glucose oxidase to the culture medium. Both the activity and the mRNA for catalase were increased following incubation of neonatal myocytes with non-toxic concentrations of glucose oxidase. The induction of mRNA preceded the enhancement of activity, and both remained elevated after 24 h incubation. Nuclear run-on assay indicated that the transcriptional rate for catalase mRNA was increased. The same treatment did not alter the activities for total superoxide dismutase and Se-glutathione peroxidase. The results suggest that H2O2-induced expression of catalase was in part due to transcriptional activation. It further implies that the induction of catalase may play an important role in protecting hearts from ischemic/reperfusion injury.

Development of GP-2 and five zymogens in the fetal and young pig: biochemical and immunocytochemical evidence of an atypical zymogen granule composition in the fetus

To uncover the mechanisms involved in the biogenesis of secretory granules, we studied development of the exocrine pancreas in the pig from the fetus up to the mature animal by following the enzyme activities and expression (Northern blot) of five zymogens and GP-2, the major protein of the granule membrane. Fetal pancreas mainly contained chymotrypsinogen and barely detectable amounts of amylase, trypsin, lipase, and elastase. GP-2 was not notably expressed before the Day 21 of life. Ultrastructural examination of the fetal tissue embedded in Epon with osmium postfixation or in Lowicryl at -20 degrees C without postfixation showed dense granules with an irregular shape but also showed that most granules had uncondensed contents, with the aspect of immature granules, or had a dense core surrounded by light material. With immunogold cytochemistry, the concentration of chymotrypsinogen was directly associated with the acquisition of electron density by the granule matrix. These observations suggest that fetal granules have a slower rhythm of zymogen condensation and an irregular shape that could be due to the particular composition of the matrix and the absence of GP-2. We conclude that, in the exocrine pancreas, secretory granules can be formed under various conditions, even with a matrix containing a ratio of components very different from that of the normal mature animal.

Partial inhibition of Na+/K+-ATPase by ouabain induces the Ca2+-dependent expressions of early-response genes in cardiac myocytes

Exposure of neonatal rat cardiac myocytes to ouabain concentrations that caused partial inhibition of Na+/K+-ATPase but no loss of viability, increased c-fos and c-jun mRNAs and the transcription factor AP-1. The increased mRNAs were proportional to the extent of inhibition of Na+/K+-ATPase and the resulting rise in steady state intracellular Ca2+ concentration. The rapid and sustained increase of c-fos mRNA was shown to be due to increased transcriptional rate. Induction of c-fos by ouabain was prevented when either extracellular or intracellular Ca2+ was lowered and was attenuated by pretreatment of myocytes with a phorbol ester under conditions known to down-regulate protein kinase C. Exposure to ouabain for 24-48 h also increased total transcriptional activity and protein content of myocytes. The findings suggest that the same signal responsible for the positive inotropic action of ouabain, i.e. net influx of Ca2+ caused by partial inhibition of Na+/K+-ATPase, also initiates the rapid protein kinase C-dependent inductions of the early-response genes, the subsequent regulations of other cardiac genes by the resulting transcription factors, and stimulation of myocyte growth. Whether these hitherto unrecognized effects of cardiac glycosides are obtained in the intact heart and their relevance to the therapeutic uses of these drugs remain to be determined.

Identification of the conserved coding sequences of three chitin synthase genes in Fonsecaea pedrosoi

Primers having designs based on highly conserved stretches in the deduced amino acid sequences of chitin synthase (CHS) genes were used in PCR reactions to amplify 600 bp and 366 bp products from the genomic DNA of three major causal agents of chromoblastomycosis. Cloning and sequencing of the PCR products of one of these fungi, Fonsecaea pedrosoi, identified three CHS sequences designated as FpCHS1, FpCHS2 and FpCHS3. FpCHS1 and FpCHS2 were homologous to regions of CHS1 and CHS2 of Saccharomyces cerevisiae, and their derived amino acid sequences fell into chitin synthase classes I and II, respectively. FpCHS3 was homologous to a region of the CAL1/CSD2 gene of S. cerevisiae, which codes for the chitin synthase three (Chs3) enzyme in that fungus. Phylogenetic trees constructed using the deduced amino acid sequences of PCR-amplified CHS products from many fungi clustered F. pedrosoi with other dematiaceous fungi, providing new molecular evidence for the genetic relatedness of these organisms. The identification of these CHS genes in F. pedrosoi will facilitate future studies of the functional roles of chitin synthases in the unique in vivo dimorphism exhibited by chromoblastomycotic fungi.

Regulation of ionic conductances and gene expression by hypoxia in an oxygen sensitive cell line

We have shown that the PC12 cell line is an excellent model system for investigations of the molecular and cellular processes involved in O2-chemosensitivity. We have identified an O2-sensitive K channel in this cell line that mediates membrane depolarization, an increase in intracellular free Ca2+, and dopamine release during hypoxia. We also presented evidence which shows that expression of the gene for tyrosine hydroxylase, the rate-limiting enzyme in dopamine biosynthesis, is stimulated by reduced O2 tension in PC12 and type I carotid body cells. In addition, we have successfully identified the DNA sequences and trans-acting protein factors that regulate transcription of the TH gene during hypoxia. The mechanisms by which a reduction in O2 tension is transduced into alter cell function including increased gene expression remain unknown. Unpublished results from our laboratory show that the increased TH gene expression during hypoxia does not require activation of the cAMP-PKA signal transduction pathway. We propose that the increase in intracellular free Ca2+ that occurs as a result of membrane depolarization might play an important role. Preliminary findings from our laboratory show that blockade of the voltage operated Ca2+ channel or chelation of intracellular Ca2+ prevent full activation of the TH gene during hypoxia.

Genetic transformation of the pathogenic fungus Wangiella dermatitidis

Genetic transformation of Wangiella dermatitidis was studied using three plasmid vectors (pAN7-1, pWU44, and pKK5) and both electroporation and polyethyleneglycol-mediated methods. pAN7-1 contains the E. coli hygromycin B (HmB) phosphotransferase (hph) gene. Expression of the hph gene confers resistance to antibiotic HmB. Selection for resistance, indicative of transformation, resulted in 10 203 HmB-resistant colonies/micrograms pAN7-1 on medium containing 100 micrograms HmB/ml. Strains of W. dermatitidis used in this study have innate sensitivity to HmB at a critical inhibitory concentration of 20-40 micrograms/ml. Vectors pWU44 and pKK5 contain a URA5 gene from Podospora anserina. A ura5 auxotroph of W. dermatitidis was transformed to prototrophy with pWU44 or pKK5 by complementation. Transformation frequencies for these two plasmids were between 17-50 transformants/micrograms vector DNA. Southern blotting analysis and polymerase chain reaction detection of DNA from putative transformants confirmed transformation.

Binding sites of monoclonal antibodies and dihydropyridine receptor alpha 1 subunit cytoplasmic II-III loop on skeletal muscle triadin fusion peptides

Triadin binds to the dihydropyridine receptor (DHPr) and the junction foot protein (JFP) in Western blot protein overlay experiments. Fusion peptides were synthesized using an expression system, pGSTag, which includes a protein kinase A phosphorylation site. Expressed peptides are DHPr664-799 encoding rabbit skeletal DHPr alpha1 subunit amino acids 664-799, triadin 1 (1-49), triadin 2 (68-389), triadin 2' (110-389), triadin 2a (68-278), triadin 2a1 (67-163), triadin 2a2 (165-240), triadin 2b (242-389), triadin 2b1 (242-299), triadin 3 (370-706), triadin 3a (370-562), triadin 3b (551-706), triadin 3b1 (551-672), and triadin 3b2 (673-706) (the numbers in parentheses correspond to the amino acid sequence of triadin). The triadin monoclonal antibodies, GE4.90 and AE8.91, bind to intact triadic vesicles as well as to vesicle fragments prepared after treatment with Triton X-100, indicating that they have cytoplasmic epitopes. MAb AE8.91 binds to triadin 2, 2', 2a, and 2a1, while mAb GE4.90 binds to triadin 3, 3b, and 3b2 indicating that residues 110-163 and the C-terminal 34 amino acids contain cytoplasmic domains. Radiolabeled DHPr664-799 binds to triadin in intact vesicles under nonreducing and reducing conditions. It binds to triadin fusion peptides, triadin 2, 2a, 3, 3b, and 3b1, but no to triadin 1 or triadin 3b2. The binding to triadin 2a is the most prominent. Direct binding between DHPr-644-799 and JFP was not seen. These experimental findings indicate that triadin contains an extensive cytoplasmic domain that binds to the domain of DHPr which is considered critical for signal transmission during skeletal muscle excitation-contraction sampling.

Interaction of echicetin with a high affinity thrombin binding site on platelet glycoprotein GPIb

Echicetin, a protein isolated from Echis carinatus snake venom, inhibited platelet aggregation and secretion induced by low concentrations of thrombin ( < 0.2 U/ml), by binding to platelet glycoprotein Ib (GPIb). The inhibition was not observed when the platelets were stimulated with higher concentrations of thrombin ( > 0.2 U/ml). Echicetin competed with thrombin for binding to the high affinity site on GPIb. Thrombin also inhibited 50% of the binding of 125I-echicetin to the platelets.

The receptor DEC-205 expressed by dendritic cells and thymic epithelial cells is involved in antigen processing

Dendritic cells and thymic epithelial cells perform important immunoregulatory functions by presenting antigens in the form of peptides bound to cell-surface major histocompatibility complex (MHC) molecules to T cells. Whereas B cells are known to present specific antigens efficiently through their surface immunoglobins, a comparable mechanism for the capture and efficient presentation of diverse antigens by dendritic cells and thymic epithelial cells has not previously been described. We show here that their antigen-presentation function is associated with the high-level expression of DEC-205, an integral membrane protein homologous to the macrophage mannose receptor and related receptors which are able to bind carbohydrates and mediate endocytosis. DEC-205 is rapidly taken up by means of coated pits and vesicles, and is delivered to a multivesicular endosomal compartment that resembles the MHC class II-containing vesicles implicated in antigen presentation. Rabbit antibodies that bind DEC-205 are presented to reactive T-cell hybridomas 100-fold more efficiently than rabbit antibodies that do not bind DEC-205. Thus DEC-205 is a novel endocytic receptor that can be used by dendritic cells and thymic epithelial cells to direct captured antigens from the extracellular space to a specialized antigen-processing compartment.

Use of the polymerase chain reaction to identify coding sequences for chitin synthase isozymes in Phialophora verrucosa

Based on conserved amino-acid regions predicted for the chitin synthases (Chs) of Saccharomyces cerevisiae, two different primer sets were synthesized and used in polymerase chain reactions (PCRs) to amplify 614-bp and 366-bp sequences from genomic DNA of the zoopathogenic fungus Phialophora verrucosa. DNA-sequencing and Southern-blotting analyses of the 614-bp DNA amplification products suggested that portions of two distinct P. verrucosa chitin synthase genes (PvCHS1, PvCHS2), coding for two different zymogenic-type PvChs isozymes, had been identified. The deduced amino-acid sequence of each fell into different Chs classes, namely class I and class II. In addition, the 366-bp DNA segment was shown to code for a conserved region having homology with the CSD2/CAL1 gene of S. cerevisiae, which encodes a nonzymogenic-type enzyme, Chs3, in that fungus. The amino-acid sequence derived from PvCHS3 exhibits 88.2% similarity and 78.4% identity to the same amino-acid region of the S. cerevisiae enzyme. These results provide a critical first step toward investigating the molecular and pathogenic importance of CHS gene regulation in this fungus and for exploring steps leading to Chs function as potential targets for the design of new therapeutic agents.

Difficulties in obtaining monoclonal antibodies to subsets of human leukocytes, using neonatal tolerance induction in mice

Many antigens are shared between different types of human leukocytes. In an effort to obtain new lineage-specific monoclonal antibodies, particularly antibodies to dendritic cells, we attempted to tolerize newborn mice to one type of leukocyte and then immunize the adults with another. We found that T cells, either unstimulated T cells or T blasts, were more effective at inducing neonatal tolerance than non-T cells or B cell lines. However, the tolerance that was achieved was not restricted to T cells, since we could not elicit from the tolerized mice a specific antibody response to a B cell line or to blood dendritic cells. Here we describe several efforts, all unsuccessful, to achieve cell specific immune responses in tolerant mice. The parameters we considered included the type of cell used to tolerize neonatal mice, the regimen of injections for inducing tolerance or eliciting immunity, and the use of several different adjuvants.