Molecular phylogenetic diversity of bacteria and its spatial distribution in composts

AIMS

To investigate microbial diversity of swine manure composts in the initial stage and the spatial distribution due to gradient effect.

METHODS AND RESULTS

Samples in different locations of a composting pile were taken and analysed by using a culture-independent approach. Total community DNA was extracted and bacterial 16S rRNA genes were subsequently amplified, cloned, restriction fragment length polymorphism-screened and sequenced. Thirty-three unique sequence types were found among the 110 analysed positive clones from superstratum sample; 56 among 122 from middle-level sample and 32 among 114 from substrate sample, respectively. The sequences related to Clostridium sp. were most common in the composts. One hundred and thirteen out of 121 16S rDNA sequence types displayed homology with those in the GenBank database. Seven 16S rDNA sequence types were not closely related to any known species. The middle-level sample had the highest microbial diversity, containing unique sequences related to Lactosphaera pasteurii, Firmicutes sp., Aerococcus sp., Megasphaera sp. and Stenotrophomonas sp.

CONCLUSIONS

Pile temperature significantly affected microbial community in the initial stage of the composting. Microbial community in different locations is quite different resulting from gradient effect.

SIGNIFICANCE AND IMPACT OF THE STUDY

Results of this study reveal high bacterial diversity in manure composts, and provide molecular evidence to support gradient effect on microbial diversity in initial stage as well.

Sonoporation of cells for drug and gene delivery

Recent studies demonstrate that ultrasound can be used to deliver compounds into viable cells for potential targeted drug delivery and non-viral gene transfection, revealing new, advantageous possibilities. The delivery is facilitated through sonoporation, the formation of temporary pores in the cell membrane induced by ultrasound. Our study focuses on the study of sonoporation mechanisms in order to achieve optimal delivery outcome such as high delivery efficiency and minimal cell death. Using voltage clamp techniques, we obtained real-time measurements of sonoporation of single Xenopus oocytes in the presence of Optison, an agent consisting of albumin-shelled C3F8 gas bubbles. Ultrasound increased the transmembrane current as a direct result of decreased membrane resistance due to pore formation. The ability to real time monitor sonoporation of cells provides a novel and necessary tool for us to study the dynamic sonoporation process and obtain optimal delivery parameters. We confirmed the delivery of compound into cells by using markers such as plasmid GFP.

Fatty acids differentially affect serotonin receptor and transporter binding in the rat brain

The aim of this study was to examine the influence of different fat diets on serotonin receptor and transporter binding. Male Sprague-Dawley rats were fed a diet of either high saturated fat, omega-6 polyunsaturated fatty acid, omega-3 polyunsaturated fatty acid or low fat (control) for eight weeks. Using Beta-Imager quantification techniques, [(3)H]ketanserin, [(3)H]mesulergine and [(3)H]paroxetine binding to serotonin (5-HT)(2A), 5-HT(2C) receptors and 5-HT transporters (5-HTT) was measured throughout the brain in all four groups. All three high fatty acid diets influenced serotonin receptor binding, however the most pronounced effects were that compared with the low fat control group, i) 5-HT(2A) receptor binding was increased in the caudate putamen, but reduced in the mammillary nucleus in high saturated fat and high omega-6 polyunsaturated fatty acid diet groups; ii) 5-HT(2C) receptor binding was reduced in the mamillary nucleus of saturated fat group and reduced in prefrontal cortex of the omega-6 polyunsaturated fatty acid and omega-3 polyunsaturated fatty acid groups; and iii) 5-HTT binding was reduced in the hippocampus in the omega-6 polyunsaturated fatty acid group. Overall, the omega-6 polyunsaturated fatty acid diet exerted the most influence on serotonin receptor and transporter binding. These results may be of importance in relation to neuropsychiatric diseases such as schizophrenia, where associations between altered fatty acid levels and the serotonergic system have been made.

Corticosterone treatment of the chick embryo affects light-stimulated development of the thalamofugal visual pathway

By injecting a single 60 microg dose of corticosterone into the eggs of domestic chicks on day 18 of incubation, we have shown that elevated levels of this hormone affect the development of asymmetry in the visual projections from the thalamus to the Wulst regions in the left and right hemispheres of the forebrain. In vehicle-treated (control) embryos this visual pathway develops asymmetry in response to light stimulation during the final stages of incubation, when the embryo is oriented so that its left eye is occluded by its body and its right eye can be stimulated by light entering through the egg shell. Pre-hatching exposure to light leads to more projections from the left side of the thalamus to the right Wulst than from the right side of the thalamus to the left Wulst, as confirmed here by injection of the tracers Fluorogold and Rhodamine into the left and right Wulst followed by counting the number of labelled cell bodies in the thalamus (asymmetry greater in males than females). The chicks injected with corticosterone pre-hatching did not develop any group bias for asymmetry in response to light exposure before hatching. They were random with respect to presence/absence of lateralization and, when present, the lateralization was not as strong as in the controls and its direction was random. The corticosterone-treated group had fewer projections from the left side of the thalamus to the right Wulst than did the controls. The results are considered with respect to maternal deposits of the hormone in the yolk and pre-hatching stress of the embryo.

Comparison of water and lipid content measurements using diffuse optical spectroscopy and MRI in emulsion phantoms

We present a quantitative comparison of lipid and water signals obtained from broadband Diffuse Optical Spectroscopy (DOS) and Magnetic Resonance Imaging (MRI). DOS and MRI measurements were performed on an identical set of emulsion phantoms that were composed of different water/soybean oil fractions. Absolute concentrations of water and lipid ranging from 35-94% and 63-6%, respectively were calculated from quantitative broadband near-infrared (NIR) absorption spectra (650-1000 nm). MR images of fat and water were separated using the three-point Dixon technique. DOS and MRI measured water and lipid were highly correlated (R(2) = 0.98 and R(2) = 0.99, respectively) suggesting that these techniques are complementary over a broad range of physiologically relevant water and lipid values. In addition, comparison of DOS derived concentrations to the MRI "gold standard" technique validates our quantitation approach and permits estimation of DOS accuracy and sensitivity in vivo.

M1-M5 muscarinic receptor knockout mice as novel tools to study the physiological roles of the muscarinic cholinergic system

A large body of evidence indicates that muscarinic acetylcholine receptors (mAChRs) play critical roles in regulating the activity of many important functions of the central and peripheral nervous systems. However, identification of the physiological and pathophysiological roles of the individual mAChR subtypes (M(1)-M(5)) has proven a difficult task, primarily due to the lack of ligands endowed with a high degree of receptor subtype selectivity and the fact that most tissues and organs express multiple mAChRs. To circumvent these difficulties, we used gene targeting technology to generate mutant mouse lines containing inactivating mutations of the M(1)-M(5) mAChR genes. The different mAChR mutant mice and the corresponding wild-type control animals were subjected to a battery of physiological, pharmacological, behavioral, biochemical, and neurochemical tests. The M(1)-M(5) mAChR mutant mice were viable and reproduced normally. However, each mutant line displayed specific functional deficits, suggesting that each mAChR subtype mediates distinct physiological functions. These results should offer new perspectives for the rational development of novel muscarinic drugs.

Molecular characterization of a distinct potyvirus from whitegrass in China

Apotyvirus isolated from perennial whitegrass ( Pennisetum centrasiaticum Tzvel.) in North China was characterized at the molecular level. The 3' terminal nucleotide (nt) sequence of 1669 nt of the viral RNA genome has been determined, which covered the coding region of the C-terminal part of the large nuclear inclusion protein (NIb, RNA polymerase), capsid protein (CP) gene and the 3' nontranslated region (NTR). The CP gene consisted of 909 nt (including the stop codon) encoding 302 amino acid residues, and the 3' NTR was 241 nt in length excluding the polyadenylated tract. Sequence comparison of the amino acids of CPs showed that this virus was most closely related to Sorghum mosaic virus and Maize dwarf mosaic virus with percent identities of 77% to 78% while that of the 3' NTRs suggested that it was most closely related to Zea mosaic virus with identity of 72%. This virus isolate was to some extent closely related to other members of the Sugarcane mosaic virus subgroup of potyviruses for the CP amino acid sequences. Phylogenetic analyses of the sequences indicated that this virus isolate represented a distinct potyvirus, and the name Pennisetum mosaic virus (PenMV) is proposed.

Smad 3 may regulate follicular growth in the mouse ovary

Although Smad 3 is known to serve as a signaling intermediate for the transforming growth factor beta (TGFbeta) family in nonreproductive tissues, its role in the ovary is unknown. Thus, we used a recently generated Smad 3-deficient (Smad 3-/-) mouse model to test the hypothesis that Smad 3 alters female fertility and regulates the growth of ovarian follicles from the primordial stage to the antral stage. In addition, we tested whether Smad 3 affects the levels of proteins that control apoptosis, survival, and proliferation in the ovarian follicle. To test this hypothesis, breeding studies were conducted using Smad 3-/- and wild-type mice. In addition, ovaries were collected from Smad 3-/- and wild-type mice on Postnatal Days 2-90. One ovary from each animal was used to estimate the total number of primordial, primary, and antral follicles. The other ovary was used for immunohistochemical analysis of selected members of the B-cell lymphoma/leukemia-2 family of protooncogenes (Bax, Bcl-2, Bcl-x), proliferating cell nuclear antigen (PCNA), and cyclin-dependent kinase 2 (Cdk-2). The results indicate that Smad 3-/- mice have reduced fertility compared with wild type mice. The results also indicate that Smad 3 may not affect the size of the primordial follicle pool at birth, but it may regulate growth of primordial follicles to the antral stage. Further, the results indicate that Smad 3 may regulate the expression of Bax and Bcl-2, but not Bcl-x, Cdk-2, and PCNA. Collectively, these data suggest that Smad 3 may play an important role in the regulation of ovarian follicle growth and female fertility.

Targeted mutagenesis of Smad1 reveals an essential role in chorioallantoic fusion

The Smad family of intracellular signaling intermediates transduce signals downstream from the transforming growth factor beta (TGF-beta) family of receptor serine threonine kinases. The original member of this family, Smad1, has been shown to mediate signals from receptors for the bone morphogenetic proteins (BMPs), a large group of ligands in the TGF-beta superfamily that mediate important developmental events. We have targeted the Smad1 gene in mice and created mutants null at this locus. Smad1 mutant mice die at approximately 9.5 days postcoitum due to defects in allantois formation. In Smad1 mutant mice, the allantois fails to fuse to the chorion, resulting in a lack of placenta and failure to establish a definitive embryonic circulation. Although vasculogenesis is initiated in the mutant allantois, the vessels formed are disorganized, and VCAM-1 protein, a marker for distal allantois development, is not expressed. Smad1 null fibroblasts are still able to respond to BMP2, however, suggesting that the defect observed in the developing extraembryonic tissue is caused by a very specific loss of transcriptional activity regulated by Smad1. Our data further demonstrate that although highly similar structurally, Smad proteins are not functionally homologous.

[Microsatellite polymorphisms at the TNF locus in Hubei Han population]

OBJECTIVE

To investigate the distribution of tumor necrosis factor(TNF) microsatellite polymorphisms in Chinese.

METHODS

DNA was extracted from 164 unrelated healthy individuals' EDTA-blood. TNF microsatellite alleles were typed using PCR technique followed by high voltage denaturing PAGE with silver staining at the same time the PCR products were cloned and sequenced.

RESULTS

Thirteen alleles and forty kinds of genotypes were detected at the TNFa locus; two alleles and three kinds of genotypes at the TNFa locus. The polymorphism information contents (PIC) were 0.80 and 0.28 respectively no deviation from Hardy-Weinberg equilibrium was observed. Statistical analysis showed that the distribution of TNFa allele frequencies in Chinese Han population was significantly different from that in European Caucasian or in Japanese P<0.01. The result of sequencing revealed that the copy number of dinucleiotide repeats within the same TNF allele was not consistent with that in the reports from western countries.

CONCLUSION

There exists ethnic difference in the distribution of TNFa allele. Further investigations will be necessary to define more accurately and clearly the TNFa alleles.

[The effects of thrombopoietin and interleukin-11 on bone marrow megakaryocytic progenitors in patients with chronic idiopathic thrombocytopenic purpura in vitro]

OBJECTIVE

To observe the effects of recombinant human thrombopoietin (rhTPO) and rhTPO in combination with recombinant human interleukin-11(rhIL-11) on the megakaryocyte (MK) colony growth and maturation in patients with chronic idiopathic thrombocytopenic purpura (CITP) in vitro.

METHODS

Bone marrow (BM) mononuclear cells of 21 patients with CITP were cultured in plasma clot culture systems, to which were added rhTPO alone or rhTPO plus rhIL-11 over a range of concentrations. After 14 days, the MK colonies were stained by GP III a Mc Ab(SZ-21) and ABC-Kit and counted. The diameters and areas of the positive cells of GP III a were measured by BM-cell analysis system of MCDS-2010.

RESULTS

The diameters and areas of MK in CITP group were significantly lower than that in control group, P < 0.05. The addition of rhTPO to culture systems increased CFU-MK, total colonies and diameters and areas of MK in CITP patients. And this promoting effect was not dose-dependent. The optimal concentration of rhTPO was 10 ng/ml; in the group where 10 ng/ml rhTPO was used in combination with 20 ng/ml rhIL-11, the counts of CFU-MK, total colonies and the measurements of areas and diameters of MK increased significantly, compared with those in the group where rhTPO was used alone.

CONCLUSION

There are maturation dysfunctions of MK progenitors in patients with CITP. rhTPO alone or in combination with rhIL-11 can promote the proliferation and maturation of MK progenitors in patients with CITP and, moreover, the combination of the two cytokines has more significant promoting effects, compared to rhTPO alone.

Antagonistic effects of Smad2 versus Smad7 are sensitive to their expression level during tooth development

Members of the transforming growth factor-beta (TGF-beta) superfamily regulate cell proliferation, differentiation, and apoptosis, controlling the development and maintenance of most tissues. TGF-beta signal is transmitted through the phosphorylation of Smad proteins by TGF-beta receptor serine/threonine kinase. During early tooth development, TGF-beta inhibits proliferation of enamel organ epithelial cells but the underlying molecular mechanisms are largely unknown. Here we tested the hypothesis that antagonistic effects between Smad2 and Smad7 regulate TGF-beta signaling during tooth development. Attenuation of Smad2 gene expression resulted in significant advancement of embryonic tooth development with increased proliferation of enamel organ epithelial cells, while attenuation of Smad7 resulted in significant inhibition of embryonic tooth development with increased apoptotic activity within enamel organ epithelium. These findings suggest that different Smads may have differential activities in regulating TGF-beta-mediated cell proliferation and death. Furthermore, functional haploinsufficiency of Smad2, but not Smad3, altered TGF-beta-mediated tooth development. The results indicate that Smads are critical factors in orchestrating TGF-beta-mediated gene regulation during embryonic tooth development. The effectiveness of TGF-beta signaling is highly sensitive to the level of Smad gene expression.

RIM4 encodes a meiotic activator required for early events of meiosis in Saccharomyces cerevisiae

RIM4 was previously found to be required for both the IME1- and IME2-dependent pathways of meiotic gene expression in Saccharomyces cerevisiae. We now demonstrate that RIM4 is also required for meiotic division and recombination. Furthermore, rim4Delta mutants show defects in premeiotic DNA synthesis, which can be suppressed by deletion of the SIC1 gene, which encodes a Cdk inhibitor. Expression of RIM4 is induced early in meiosis, and is dependent on IME1 but not IME2. Indeed, RIM4 itself is essential for the meiotic expression of IME2. These results suggest that RIM4 is epistatic to IME2, and is required for multiple steps during sporulation. In agreement with this interpretation, overexpression of RIM4 induces low levels of sporulation in rich medium.

Motor deficits in fibroblast growth factor receptor-3 null mutant mice

Fibroblast growth factor receptor-3 (FGFR-3) regulates aspects of bone development. Mutations in the FGFR-3 gene (Fgfr3) in humans and mice produce vertebral abnormalities and bone deformities. The present study evaluated the behavioural concomitants of the Fgfr3-/- mutation. Fgfr3-/- null mutant mice displayed severe impairments of motor abilities as detected on the rotarod, wire hang and open field tests. Absence of prepulse inhibition of acoustic startle was seen at prepulse levels from 74 to 86 dB. The motor deficits appear to be a direct and predicted consequence of the skeletal kyphosis, scoliosis and long bone overgrowth previously reported in Fgfr3 null mutant mice. The behavioural phenotype displayed by these mutant mice complements their anatomical, physiological and biochemical phenotypes, to complete the characterization of the functional outcome of a single gene mutation. Simple, robust behavioural symptoms, such as poor rotorod performance in Fgfr3 knockout mice, can provide useful surrogate markers to evaluate pharmacological treatments and gene therapies for human genetic diseases.

[Association of tumor necrosis factor microsatellite polymorphism with chronic atrophic gastritis and gastric adenocarcinoma]

OBJECTIVE

To investigate whether TNFd and TNFe microsatellite polymorphisms correlate with chronic atrophic gastritis and gastric adenocarcinoma in Chinese Han population.

METHODS

In 164 healthy controls, 53 patients with chronic atrophic gastritis, and 56 patients with gastric adenocarcinoma, TNFd and TNFe microsatellite alleles were typed using PCR technique, followed by high-voltage denaturing PAGE, with silver staining. At the same time, the PCR products were cloned and sequenced.

RESULTS

Fight alleles at the TNFd locus and four alleles at the TNFe locus were detected. A new allele was found and identified, its accession number of Genebank is AF315593. Statistical analysis showed that there existed a very strong linkage equilibrium between TNFd8 and TNFe4 allele. No difference was observed between patients and healthy controls in the distribution of alleles at the TNFd and TNFe loci (P > 0.05). The frequence of d2/d6 genotype was significantly higher in patients with gastric adenocarcinoma than in healthy individuals (P = 0.028). d2/d6 genotype wasn't related to age or gender or grade of differentiation or clinicopathologic stage in gastric adenocarcinoma.

CONCLUSION

d8e4 haplotype appears to be specific of Chinese population. d2/d6 genotype is associated with the susceptibility to gastric adenocarcinoma.

[Vacuolation effect of Helicobacter pylori on gastric epithelial cells]

This study was designed to observe vacuolation effect of Helicobacter pylori on gastric epithelial cells. The H. pylori isolates derived from patients with peptic ulcer, chronic gastritis and gastric cancer were plated on common selective medium and their vacuolation effects on SGC-7901 cells were compared. The percentage of H. pylori(Tox+) strain in clinical isolates from different gastroduodenal diseases had no significant difference. The toxicity of the H. pylori (Tox+) strain from peptic ulcer was significantly higher than that from chronic gasritis.

[The relativity study of thrombopoietin and chronic idiopathic thrombocytopenic purpura]

OBJECTIVE

To explore the relationship between thrombopoietin (Tpo) levels and reticulated platelet (RP), blood platelet count (BPC), maturity of megakaryocytes in patients with chronic idiopathic thrombocytopenic purpura (CITP), and the prediction evaluation according to Tpo levels.

METHODS

Serum level of Tpo was measured by a sandwich-ELISA procedure, RP by flow cytometry after stained with thizole orange (TO), and maturity of megakaryocytes by laser scanning confocal microscopy (LSCM).

RESULTS

The serum level of Tpo was (204.05 +/- 65.70) ng/L in 23 normal controls and (345.46 +/- 222.23) ng/L in 33 patients with CITP, being no significant difference between the two groups (P > 0.05). Compared with controls, serum Tpo levels in 22 aplastic anemia(AA) patients [(1427.62 +/- 468.84) ng/L] and 10 acute myelogenous leukemia (AML) patients [(596.09 +/- 462.95) ng/L] were increased significantly (P < 0.05). The RPC was significantly lower in AA and AML patients (P < 0.05). The RP% was increased significantly in CITP and AML patients (P < 0.05). The Tpo level was higher in CITP patients with no response to glucocorticoid therapy than in those with response (P < 0.05).

CONCLUSION

Serum level of Tpo was not increased in patients with CITP. The RP%, RPC and Tpo levels could reflect thrombocytopoiesis and differentiate the causes of thrombocytopenia. The serum level of Tpo could be useful in prediction of the response to therapy in CITP patients.

ADY1, a novel gene required for prospore membrane formation at selected spindle poles in Saccharomyces cerevisiae

ADY1 is identified in a genetic screen for genes on chromosome VIII of Saccharomyces cerevisiae that are required for sporulation. ADY1 is not required for meiotic recombination or meiotic chromosome segregation, but it is required for the formation of four spores inside an ascus. In the absence of ADY1, prospore formation is restricted to mainly one or two spindle poles per cell. Moreover, the two spores in the dyads of the ady1 mutant are predominantly nonsisters, suggesting that the proficiency to form prospores is not randomly distributed to the four spindle poles in the ady1 mutant. Interestingly, the meiosis-specific spindle pole body component Mpc54p, which is known to be required for prospore membrane formation, is localized predominantly to only one or two spindle poles per cell in the ady1 mutant. A partially functional Myc-Pfs1p is localized to the nucleus of mononucleate meiotic cells but not to the spindle pole body or prospore membrane. These results suggest that Pfs1p is specifically required for prospore formation at selected spindle poles, most likely by ensuring the functionality of all four spindle pole bodies of a cell during meiosis II.

Overexpression of Smad2 reveals its concerted action with Smad4 in regulating TGF-beta-mediated epidermal homeostasis

Members of the transforming growth factor-beta (TGF-beta) superfamily are critical regulators for epithelial growth and can alter the differentiation of keratinocytes. Transduction of TGF-beta signaling depends on the phosphorylation and activation of Smad proteins by heteromeric complexes of ligand-specific type I and II receptors. To understand the function of TGF-beta and activin-specific Smad, we generated transgenic mice that overexpress Smad2 in epidermis under the control of keratin 14 promoter. Overexpression of Smad2 increases endogenous Smad4 and TGF-beta 1 expression while heterozygous loss of Smad2 reduces their expression levels, suggesting a concerted action of Smad2 and -4 in regulating TGF-beta signaling during skin development. These transgenic mice have delayed hair growth, underdeveloped ears, and shorter tails. In their skin, there is severe thickening of the epidermis with disorganized epidermal architecture, indistinguishable basement membrane, and dermal fibrosis. These abnormal phenotypes are due to increased proliferation of the basal epidermal cells and abnormalities in the program of keratinocyte differentiation. The ectodermally derived enamel structure is also abnormal. Collectively, our study presents the first in vivo evidence that, by providing an auto-feedback in TGF-beta signaling, Smad2 plays a pivotal role in regulating TGF-beta-mediated epidermal homeostasis.

Post-transplant lymphoproliferative disease in children

Epstein-Barr virus (EBV)-driven post-transplant lymphoproliferative disease (PTLD) is an important cause of morbidity and mortality following transplantation, and it occurs more frequently in children than in adults. Of 22 (5%) children at our institution who developed tissue-proven PTLD 1-60 months (mean 16.5 months) following organ transplant, 11 died: nine of these 22 patients developed PTLD between 1989 and 1993, and seven (78%) died; the remaining 13 developed PTLD between 1994 and 1998, and four (31%) died (p = 0.08). All nine patients who developed PTLD < 6 months after transplant died, but 11 of 13 patients who manifested disease > or = 6 months after transplant survived (p = 0.0002). Ten of 11 (91%) survivors, but only two of eight (25%) children who died, had serologic evidence of EBV infection at the time of PTLD diagnosis (p = 0.04). EBV seroconversion identified patients at risk for developing PTLD, but also characterized patients with sufficient immune function to survive EBV-related lymphoid proliferation. In situ hybridization for EBER1 mRNA was diagnostically helpful because it detected EBV in tissue sections of all 20 patients with B-cell PTLD, including those with negative serology.

Similarity of the song nuclei of male and female Australian magpies (Gymnorhina tibicen)

The organisation of the song control nuclei of the Australian magpie (Gymnorhina tibicen), a species with highly complex song, was investigated. In contrast to most of the songbirds studied so far, the Australian magpie sings throughout the year and both males and females sing. All of the forebrain song nuclei, including the high vocal centre (HVC), the robust nucleus of the archistriatum (RA), Area X and the lateral and medial magnocellular nuclei of the anterior neostriatum (lMAN and mMAN) were found to be well developed in both male and female magpies. Consistent with the known vocal competence of juvenile magpies, all of the song nuclei were also well-developed in juvenile magpies (2--3 months old). HVC in both male and female magpies consists of a rostrolateral and a caudomedial region. The ventromedial part of RA differs from the dorsolateral part by having medium-sized neurons packed in higher density. The HVC to RA projections were labelled anterogradely by DiI and DiA. However, no HVC to Area X projections were labeled by DiI or DiA, suggesting a possible difference from songbirds studied previously.

Functional characterization of transforming growth factor beta signaling in Smad2- and Smad3-deficient fibroblasts

A prominent pathway of transforming growth factor (TGF)-beta signaling involves receptor-dependent phosphorylation of Smad2 and Smad3, which then translocate to the nucleus to activate transcription of target genes. To investigate the relative importance of these two Smad proteins in TGF-beta1 signal transduction, we have utilized a loss of function approach, based on analysis of the effects of TGF-beta1 on fibroblasts derived from mouse embryos deficient in Smad2 (S2KO) or Smad3 (S3KO). TGF-beta1 caused 50% inhibition of cellular proliferation in wild-type fibroblasts as assessed by [(3)H]thymidine incorporation, whereas the growth of S2KO or S3KO cells was only weakly inhibited by TGF-beta1. Lack of Smad2 or Smad3 expression did not affect TGF-beta1-induced fibronectin synthesis but resulted in markedly suppressed induction of plasminogen activator inhibitor-1 by TGF-beta1. Moreover, TGF-beta1-mediated induction of matrix metalloproteinase-2 was selectively dependent on Smad2, whereas induction of c-fos, Smad7, and TGF-beta1 autoinduction relied on expression of Smad3. Investigation of transcriptional activation of TGF-beta-sensitive reporter genes in the different fibroblasts showed that activation of the (Smad binding element)(4)-Lux reporter by TGF-beta1 was dependent on expression of Smad3, but not Smad2, whereas activation of the activin response element-Lux reporter was strongly suppressed in S2KO fibroblasts but, on the contrary, enhanced in S3KO cells. Our findings indicate specific roles for Smad2 and Smad3 in TGF-beta1 signaling.

Unexpected effects of a heterozygous dnmt1 null mutation on age-dependent DNA hypomethylation and autoimmunity

DNA methylation modifies gene expression. Methylation patterns are established during ontogeny, but they change with aging, usually with a net decrease in methylation. The significance of this change in T cells is unknown, but it could contribute to autoimmunity, senescence, or both. We examined the effects of a null mutation in DNA methyltransferase 1 (Dnmt1), a gene maintaining DNA methylation patterns, on immune aging. Whereas aged control mice developed hypomethylated DNA, autoimmunity, and signs of immune senescence as predicted, the knockout mice surprisingly increased DNA methylation and developed signs of autoimmunity and senescence more slowly. To identify potential mechanisms, we compared transcripts of DNA methyltransferase and methylcytosine binding protein family members in control and knockout mice. MeCP2, a methylcytosine binding protein involved in gene suppression and chromatin inactivation, was the only transcript differentially expressed between old knockout mice and controls, and thus it is a candidate for a gene product mediating these effects.

[Investigation on an outbreak of Legionnaires' disease caused by Lboz in a suburb of Beijing]

OBJECTIVE

To demonstrate the infectious rates and incidence rates through epidemiological investigation.

METHODS

Serum samples from 203 new soldiers were detected from Lboz by TAT.

RESULTS

Infectious rates was 33.00% (67/203), and the incidence rates was 8.87% (18/203) with 2 cases of pneumonic type and 16 cases of pontiac fever type.

CONCLUSION

The results suggested that an outbreak of Legionnaires' desease caused by Legionella bozemanii (Lboz) took place in a suburb of Beijing. However the report of the outbreak caused by Lboz had not been found in related references.

Human cytochrome P450 isozymes in metabolism and health effects of gasoline ethers

To reduce the production of carbon monoxide and other pollutants in motor vehicle exhaust, methyl tert-butyl ether (MTBE*), ethyl tert-butyl ether (ETBE), and tert-amyl methyl ether (TAME) are added to gasoline as oxygenates for more complete combustion. Among them, MTBE is the most widely used. The possible adverse effect of MTBE in humans is a public concern, but the human enzymes responsible for metabolism of these gasoline ethers and the causes or factors for increased sensitivity to MTBE in certain individuals are totally unknown. This information is important to understanding the health effects of MTBE in humans and to assessing the human relevance of pharmacokinetics and toxicity data obtained from animals. In the present study, we demonstrated that human liver is active in metabolizing MTBE to tert-butyl alcohol (TBA), a major circulating metabolite and an exposure marker of MTBE. The activity is localized in the microsomal fraction but not in the cytosol. Formation of TBA in human liver microsomes is NADPH-dependent and is significantly inhibited by carbon monoxide, which inhibits cytochrome P450 (CYP) enzymes. These results provide strong evidence that CYP enzymes play a critical role in the metabolism of MTBE in human livers. Human liver is also active in the oxidative metabolism of 2 other gasoline ethers, ETBE and TAME. We observed a large interindividual variation in metabolizing these gasoline ethers in 15 microsomal samples prepared from normal human livers. The activity level (pmol metabolite/min/mg) ranged from 204 to 2,890 for MTBE; 179 to 3,134 for ETBE; and 271 to 8,532 for TAME. The microsomal activities in metabolizing MTBE, ETBE, and TAME correlated highly with each other (r = 0.91 to 0.96), suggesting that these ethers are metabolized by the same enzyme(s). Correlation analysis of the ether-metabolizing activities with individual CYP enzyme activities in the human liver microsomes showed that the highest degree of correlation was with CYP isoform 2A6 (CYP2A6)+ (r = 0.94 for MTBE, 0.95 for ETBE, and 0.90 for TAME), which is constitutively expressed in human livers and known to be polymorphic. CYP2A6 displayed the highest turnover number in metabolizing gasoline ethers among a battery of human CYP enzymes expressed in human B-lymphoblastoid cells. CYP2A6 coexpressed with human CYP reductase by a baculovirus expression system was also more active than CYP isoform 2E1 (CYP2E1) in the metabolism of MTBE, ETBE, and TAME. Kinetic studies on MTBE metabolism with human liver microsomes (n = 3) exhibited an apparent Michaelis constant (Km) of 28 to 89 microM and a maximum rate of metabolism (Vmax) of 215 to 783 pmol/min/mg. Metabolism of MTBE, ETBE, and TAME by human liver microsomes was inhibited by coumarin, a known substrate of human CYP2A6, in a concentration-dependent manner. Monoclonal antibody against human CYP2A6 caused a significant inhibition (75% to 95%) of the metabolism of MTBE, ETBE, and TAME in human liver microsomes. Taken together, these results clearly indicate that, in human liver, CYP2A6 is a major enzyme responsible for metabolism of MTBE, ETBE, and TAME. Although CYP2E1 metabolizes diethyl ether and was previously suggested to be involved

[Hypermethylation of the calcitonin gene as molecular genetic marker in detecting minimal residual disease of leukemia]

OBJECTIVE

To explore whether detecting minimal residual disease (MRD) of leukemia with hypermethylation of the calcitonin gene as molecular genetic marker of leukemic clone may predict the prognosis.

METHODS

Polymerase chain reaction (PCR) in combination with digestion of DNA with HpaII was used to examine the methylation patterns of the calcitonin gene in 29 cases with acute leukemia and 8 cases with transformation of chronic myeloid leukemia. By using PCR, MRD was longitudinally detected in patients who were positive for hypermethylation of the calcitonin gene as molecular genetic marker.

RESULTS

Twenty patients with acute leukemia and transformation of chronic myeloid leukemia had MRD after complete remission. Bone marrow relapse occurred soon when MRD persisted or reappeared. It may predict bone marrow relapse two to eleven months earlier. The patients who were negative for MRD early and remained persistently negative may acquire prolonged survival.

CONCLUSION

MRD of leukemia may be monitored by using PCR with hypermethylation of the calcitonin gene as molecular genetic marker for leukemic clone. It may prove useful in predicting the prognosis of leukemia.

Mice expressing only monosialoganglioside GM3 exhibit lethal audiogenic seizures

Gangliosides are a family of glycosphingolipids that contain sialic acid. Although they are abundant on neuronal cell membranes, their precise functions and importance in the central nervous system (CNS) remain largely undefined. We have disrupted the gene encoding GD3 synthase (GD3S), a sialyltransferase expressed in the CNS that is responsible for the synthesis of b-series gangliosides. GD3S-/- mice, even with an absence of b-series gangliosides, appear to undergo normal development and have a normal life span. To further restrict the expression of gangliosides, the GD3S mutant mice were crossbred with mice carrying a disrupted GalNAcT gene encoding beta1,4-N-acetylgalactosaminyltransferase. These double mutant mice expressed GM3 as their major ganglioside. In contrast to the single mutant mice, the double mutants displayed a sudden death phenotype and were extremely susceptible to induction of lethal seizures by sound stimulus. These results demonstrate unequivocally that gangliosides play an essential role in the proper functioning of the CNS.

[Study on hypermethylation of the calcitonin gene in malignant hematological disorders]

OBJECTIVE

To investigate the clinical significance of hypermethylation of the calcitonin (CT) gene in malignant hematological disorders (MHD).

METHODS

Polymerase chain reaction (PCR) in combination with digestion of DNA with Hpa II was used to examine the methylation patterns of the CT gene in 73 patients with MHD, 6 healthy people and 24 patients with nonmalignant hematological disorders (NON-MHD).

RESULTS

Hypermethylation of the CT gene occurred in 12 of 14 (85.7%) patients with acute lymphoblastic leukemia (ALL), 9 of 15 (60%) acute nonlymphocytic leukemia (ANLL), 8 of 10 (80%) chronic myelogenous leukemia (CML), 5 of 15 (33.3%) malignant lymphoma (ML), 2 of 5 patients with myelodysplastic syndrome (MDS), 1 of 2 malignant histiocytosis (MH), 1 of 3 chronic lymphocytic leukemia (CLL) and 1 of 9 multiple myeloma (MM). However, it did not occur in normal controls and NON-MHD.

CONCLUSION

Hypermethylation of CT gene may serve as an important molecular maker for tumorous cell clone and may be useful in diagnosing MHD, monitoring minimal residual disease and predicting prognosis.

A Ser(365)-->Cys mutation of fibroblast growth factor receptor 3 in mouse downregulates Ihh/PTHrP signals and causes severe achondroplasia

Missense mutations in fibroblast growth factor receptor 3 (FGFR3) result in several types of human skeletal dysplasia, including the neonatally lethal dwarfism known as thanatophoric dysplasia. An engineered Ser(365)-->Cys substitution in mouse FGFR3, which is equivalent to a mutation associated with thanatophoric dysplasia-I in humans, has now been shown to cause severe dwarfism but not neonatal death. The mutant mice exhibit shortened limbs as a result of markedly reduced proliferation and impaired differentiation of growth plate chondrocytes. The receptor-activating mutation also resulted in downregulation of expression of the Indian hedgehog (IHH) and parathyroid hormone-related protein (PTHrP) receptor genes, both of which are important for bone growth. Interactions between FGFR3- and PTHrP-receptor-mediated signals during endochondral ossification were examined with embryonic metatarsal bones maintained in culture under defined conditions. Consistent with the in vivo observations, FGF2 inhibited bone growth in culture and induced downregulation of IHH and PTHrP receptor gene expression. Furthermore, PTHrP partially reversed the inhibition of long bone growth caused by activation of FGFR3; however, it impaired the differentiation of chondrocytes in an FGFR3-independent manner. These observations suggest that FGFR3 and IHH-PTHrP signals are transmitted by two interacting parallel pathways that mediate both overlapping and distinct functions during endochondral ossification.

Fas/Fas ligand pathway, apoptosis, and clonal anergy involved in systemic acetylcholine receptor T cell epitope tolerance

The cellular mechanisms of high dose systemic acetylcholine receptor (AChR) T cell epitope, alpha 146--162 peptide-induced tolerance in experimental myasthenia gravis were examined. CD4 cells are the prime target for alpha 146--162 peptide-induced tolerance. The expression of CD69, Fas, and B7.2 molecules on AChR-immune lymphocytes was enhanced within 4--12 h after tolerance induction. A high dose of alpha 146--162 peptide in IFA failed to suppress T cell proliferation and/or clinical myasthenia gravis in lpr and gld mice deficient in Fas and Fas ligand, respectively. A high dose of alpha 146--162 peptide in IFA in AChR-immunized mice induced apoptosis of BV6 cells. Further, reconstitution of IL-2 in vitro-recovered alpha 146--162 peptide tolerized T cell proliferation, IFN-gamma, and IL-10 production. The findings implicate the possible role of Fas-/Fas ligand-mediated apoptosis and the resulting clonal anergy as the mechanisms of high dose AChR alpha 146--162 peptide-induced tolerance on CD4 cells.

Role of nerve growth factor in experimental autoimmune encephalomyelitis

The expression of neural regulatory molecules by immune cells that infiltrate the nervous system upon injury may be a mechanism for cross-regulation between the nervous system and the immune system. Several lines of evidence implicate nerve growth factor (NGF) signaling through its receptors (TrkA and p75(NGFR)) as a potential source of communication between the two systems. We observed changes in NGF mRNA expression and protein secretion by T lymphocytes polarized toward the Th2 phenotype. The presence of NGF did not affect T cell proliferation or cytokine production in vitro. Mice treated with NGF by i. p. injection following induction of experimental autoimmune encephalomyelitis, an inflammatory, demyelinating disease of the central nervous system, showed a delayed onset of disease and lower clinical scores during the course of disease. These data suggest a role for NGF signaling in the regulation of the immune response, possibly by enhancing sympathetic innervation of lymphoid tissues.

Decreased Ras-mitogen-activated protein kinase signaling may cause DNA hypomethylation in T lymphocytes from lupus patients

OBJECTIVE

Previous studies have shown that inhibiting T cell DNA methylation causes a lupus-like disease by modifying gene expression. T cells from patients with lupus exhibit diminished levels of DNA methyltransferase (MTase) enzyme activity, hypomethylated DNA, and changes in gene expression similar to those exhibited by T cells treated with methylation inhibitors, suggesting that DNA hypomethylation may contribute to human lupus. Since it is known that DNA MTase levels are regulated by the ras-mitogen-activated protein kinase (MAPK) pathway, this study sought to determine whether decreased ras-MAPK signaling could account for the DNA hypomethylation in lupus T cells.

METHODS

DNA MTase messenger RNA (mRNA) from lupus patients and from healthy controls was quantitated by Northern analysis, and ras-MAPK signaling was determined by immunoblotting with antibodies to the activated forms of extracellular receptor-associated kinase (ERK). Results were compared with those in T cells in which ras-MAPK signaling was inhibited with a soluble inhibitor of MAPK ERK I (MEK1).

RESULTS

T cells from patients with active lupus had diminished DNA MTase mRNA levels and decreased signaling through the ras-MAPK pathway. Inhibiting signaling through the ras-MAPK pathway with the MEK1 inhibitor decreased DNA MTase mRNA and enzyme activity to the levels seen in lupus T cells, and resulted in DNA hypomethylation resembling that seen in lupus T cells.

CONCLUSION

These results suggest that a decrease in signaling through the ras-MAPK pathway may be responsible for the decreased MTase activity and DNA hypomethylation in patients with lupus.

Lymphotoxin-alpha deficiency completely protects C57BL/6 mice from developing clinical experimental autoimmune myasthenia gravis

A complete prevention of clinical experimental autoimmune myasthenia gravis (EAMG) was observed in lymphotoxin (LT)-alpha deficient (LT-alpha(-/-)) mice compared to LT-alpha(+/+) mice when immunized with acetylcholine receptor. However, only a partial prevention of clinical EAMG incidence was observed in LT-beta(-/-) mice compared to LT-beta(+/+) mice. LT-alpha(-/-)and LT-beta(-/-) mice had lower mean titers of total IgG, IgG(1), IgG(2a) and IgG(2b) and higher or equal mean titers of IgM anti-AChR antibodies compared to controls. Therefore, LT-alpha(-/-)and LT-beta(-/-) AChR immunized mice are capable of mounting a primary (IgM) humoral immune response to AChR, but are less capable of switching to the pathogenic anti-AChR IgG isotypes. LT could play a significant role in the pathogenesis of myasthenia gravis.

Detecting hormesis using a non-parametric rank test

When a dose-response experiment is conducted, the enhanced responses can be observed at low doses. This phenomenon is often called hormesis. The enhanced responses at low doses does not necessarily mean the existence of hormesis. It is important to conduct statistical analyses to determine whether a departure from monotonic relationships is significantly different from the chance occurrence. This paper introduces a non-parametric rank test to detect hormesis. To illustrate the use of this method, we apply it to the data from a Whole Effluent Toxicity test. We demonstrate that the occurrence of hormesis can be statistically evaluated by using this non-parametric rank test.

Generation and phenotype of mice harboring a nonsense mutation in the V2 vasopressin receptor gene

The V2 vasopressin receptor (V2R) plays a key role in the maintenance of a normal body water balance. To generate an in vivo model that allows the physiological and molecular analysis of the role of V2Rs in kidney function, we have created mouse lines that lack functional V2Rs by using targeted mutagenesis in mouse embryonic stem cells. Specifically, we introduced a nonsense mutation known to cause X-linked nephrogenic diabetes insipidus (XNDI) in humans (Glu242stop) into the mouse genome. V2R-deficient hemizygous male pups showed a decrease in basal urine osmolalities and were unable to concentrate their urine. These pups also exhibited an enlargement of renal pelvic space, failed to thrive, and died within the first week after birth due to hypernatremic dehydration. Interestingly, female mice heterozygous for the V2R mutation showed normal growth but displayed an XNDI-like phenotype, characterized by reduced urine concentrating ability of the kidney, polyuria, and polydipsia. Western blot analysis and immunoelectron microscopic studies showed that the loss of functional V2Rs had no significant effect on the basal expression levels of aquaporin-2 and the bumetanide-sensitive Na-K-2Cl cotransporter (BSC-1). The V2R mutant mice described here should serve as highly useful tools for the development of novel therapeutic strategies for the treatment of XNDI.

Resistance to apoptosis in HIV-infected CD4+ T lymphocytes is mediated by macrophages: role for Nef and immune activation in viral persistence

Apoptosis or programmed cell death may play a critical role in AIDS pathogenesis through depletion of both CD4(+) and CD8(+) T lymphocytes. Using a reporter virus, a recombinant HIV infectious clone expressing the green fluorescent protein (GFP), apoptosis was measured in productively infected CD4(+) T lymphocytes, in the presence and absence of autologous macrophages. The presence of macrophages in the culture increased the frequency of nonapoptotic GFP-positive productively infected CD4(+) T lymphocytes. The appearance of nonapoptotic productively infected CD4(+) T lymphocytes in the culture required intercellular contacts between macrophages and PBLs and the expression of the HIV Nef protein. The presence of macrophages did not reduce apoptosis when CD4(+) T lymphocytes were infected with a GFP-tagged virus deleted for the nef gene. TNF-alpha (TNF) expressed on the surface of macrophages prevented apoptosis in nef-expressing, productively infected CD4(+) T lymphocytes. Similarly, following TNF stimulation, apoptosis was diminished in Jurkat T cells transfected with a nef-expressing plasmid. TNF stimulation of nef-expressing Jurkat T cells resulted in NF-kappaB hyperactivation, which has been shown to deliver anti-apoptotic signals. Our results indicate that intercellular contacts with macrophages increase the rate of productively infected nonapoptotic CD4(+) T lymphocytes. The survival of productively infected CD4(+) T lymphocytes requires Nef expression as well as activation by TNF expressed on the surface of macrophages and might participate in the formation and maintenance of viral reservoirs in HIV-infected persons.

DNA methylation in the regulation of T cell LFA-1 expression

Inducing T cell LFA-1 overexpression by transfection, or by treatment with DNA methylation inhibitors including 5-azacytidine, procainamide and hydralazine, causes MHC-specific T cell autoreactivity in vitro and autoimmunity in vivo. How DNA methylation inhibitors increase LFA-1 expression is unknown. In this report we identify a mechanism by which DNA methylation affects LFA-1 expression. Nuclear run-on assays demonstrated that inhibiting DNA methylation increased transcription of CD11a but not CD18 or beta-actin mRNA. CD11a mRNA stability was not affected. Transfection of hypomethylated cells with reporter constructs containing the CD11a promoter showed no role for overexpression of transcription factors. However, the CD11a promoter demethylated following treatment with DNA methyltransferase inhibitors, and in vitro methylation of the construct suppressed its expression. Together, these results indicate that DNA methylation inhibitors can cause LFA-1 overexpression directly by demethylating the CD11a promoter. This mechanism could contribute to T cell autoreactivity, and potentially to autoimmunity.

[Clinical study on interferon treatment of chronic idiopathic thrombocytopenic purpura]

The efficacy and mechanism of interferon alpha-2a (IFN alpha-2a) were assessed in the treatment of chronic idiopathic thrombocytopenic purpura (cITP). 20 patients with cITP (treatment group) were treated with IFN alpha-2a 3MIU i.m. once a week for 8 weeks; 28 patients with cITP (control group) were treated with prednisone 1 mg/(kg.d) for 4 weeks. Blood platelet counts (BPC), megakaryocyte number, immunnological parameters, percent and absolute counts of reticulated platelets (RPs) and megakaryocyte colony formation units were observed before and after therapy. The results showed that the efficacy of IFN alpha-2a was better than that of corticosteroid, P < 0.05. The RPs% decreased and the platelet-producing megakaryocyte percentage increased from 11.43% to 33.19% significantly after IFN alpha-2a therapy, but there were no significant changes in immunnological parameters. These indicate that IFN alpha-2a is effective in treating cITP, the mechanism may be based on promoting the megakaryocyte development and activating the production of platelets.

Functional collaboration between different cyclin-dependent kinase inhibitors suppresses tumor growth with distinct tissue specificity

The presence of two families of seven distinct mammalian cyclin-dependent kinase (CDK) inhibitor genes is thought to mediate the complexity of connecting a variety of cellular processes to the cell cycle control pathway. The distinct pattern of tissue expression of CDK inhibitor genes suggests that they may function as tumor suppressors with different tissue specificities. To test this hypothesis, we have characterized two strains of double mutant mice lacking either p18(INK4c) and p27(KIP1) or p18(INK4c) and p21(CIP1/WAF1). Loss of both p18 and p27 function resulted in the spontaneous development by 3 months of age of at least eight different types of hyperplastic tissues and/or tumors in the pituitary, adrenals, thyroid, parathyroid, testes, pancreas, duodenum, and stomach. Six of these hyperplastic tissues and tumors were in endocrine organs, and several types of tumors routinely developed within the same animal, a phenotype reminiscent of that seen in combined human multiple endocrine neoplasia syndromes. The p18-p21 double null mice, on the other hand, developed pituitary adenomas, multifocal gastric neuroendocrine hyperplasia, and lung bronchioalveolar tumors later in life. G(1) CDK2 and CDK4 kinase activities were increased in both normal and neoplastic tissues derived from mice lacking individual CDK inhibitors and were synergistically stimulated by the simultaneous loss of two CDK inhibitors. This indicates that an increase in G(1) CDK kinase activity is a critical step during but is not sufficient for tumor growth. Our results suggest that functional collaborations between distinct CDK inhibitor genes are tissue specific and confer yet another level of regulation in cell growth control and tumor suppression.

The steroid receptor coactivator SRC-3 (p/CIP/RAC3/AIB1/ACTR/TRAM-1) is required for normal growth, puberty, female reproductive function, and mammary gland development

Steroid receptor coactivator-3 (SRC-3) is a coactivator of nuclear receptors in the SRC family as assayed in vitro. Here, we show that mouse SRC-3 is expressed in a tissue-specific fashion and distributed mainly in the oocytes, mammary glands, hippocampus, olfactory bulb, smooth muscle, hepatocytes, and vaginal epithelium. Genetic disruption of SRC-3 in mice results in a pleiotropic phenotype showing dwarfism, delayed puberty, reduced female reproductive function, and blunted mammary gland development. Hormonal analysis indicates that SRC-3 plays a role in both the growth hormone regulatory pathway and the production of estrogen, which may explain the observed phenotypes. These results suggest that the physiological role of SRC-3 is different from that of SRC-1 and prove the diversity among coactivator family members.

Disability case management: an impact assessment in an automotive manufacturing organization

A multifaceted disability management program was instituted at an automotive manufacturing organization to control rising workers' compensation costs. A pilot program showed major cost savings over a 9-month period. When total and component disability leave rates were calculated as a percentage of the available workforce and tracked on a weekly basis over the subsequent 3 years, total disability leave rates fell by nearly 50%. This was largely attributable to an approximately 50% decrease in the extended (> 1-year) disability leave rate and a 75% decrease in the workers' compensation leave rate. A novel approach to biostatistical analysis showed a good fit of weekly disability leave rates to a Poisson random variable distribution with an identifiable break point at about 1 1/2 years after observation for extended disability leaves and at 2 years for workers' compensation leaves. This biostatistical approach may prove generalizable to tracking leave rates in other organizations.