Construction of a novel expression cassette for increasing transgene expression in vivo in endothelial cells of large blood vessels

The success of gene therapy hinges on achievement of adequate transgene expression. To ensure high transgene expression, many gene-therapy vectors include highly active virus-derived transcriptional elements. Other vectors include tissue-specific eukaryotic transcriptional elements, intended to limit transgene expression to specific cell types, avoid toxicity and prevent immune responses. Unfortunately, tissue specificity is often accompanied by lower transgene expression. Here, we use eukaryotic (murine) transcriptional elements and a virus-derived posttranscriptional element to build cassettes designed to express a potentially therapeutic gene (interleukin (IL)-10) in large-vessel endothelial cells (ECs) at levels as high as obtained with the cytomegalovirus (CMV) immediate early promoter, while retaining EC specificity. The cassettes were tested by incorporation into helper-dependent adenoviral vectors, and transduction into bovine aortic EC in vitro and rabbit carotid EC in vivo. The murine endothelin-1 promoter showed EC specificity, but expressed only 3% as much IL-10 mRNA as CMV. Inclusion of precisely four copies of an EC-specific enhancer and a posttranscriptional regulatory element increased IL-10 expression to a level at or above the CMV promoter in vivo, while retaining--and possibly enhancing--EC specificity, as measured in vitro. The cassette reported here will likely be useful for maximizing transgene expression in large-vessel EC, while minimizing systemic effects.

Support for smoke-free policies among smokers and non-smokers in six cities in China: ITC China Survey

OBJECTIVE

To examine levels of support for comprehensive smoke-free policies in six large Chinese cities.

METHODS

Data from Wave 1 of the International Tobacco Control (ITC) China Survey (April-August 2006) were analysed. The ITC China Survey employed a multistage sampling design in Beijing, Shenyang, Shanghai, Changsha, Guangzhou and Yinchuan (none of which has comprehensive smoke-free policies in place). Face-to-face interviews were conducted with 4815 smokers and 1270 non-smokers. Multivariate logistic regression models were used to identify factors associated with support for comprehensive smoke-free policies.

RESULTS

About one in two Chinese urban smokers and four in five non-smokers believed that secondhand smoke (SHS) causes lung cancer. The majority of respondents supported comprehensive smoke-free policies in hospitals, schools and public transport vehicles while support for smoke-free workplaces, restaurants and bars was lower. Levels of support were generally comparable between smokers and non-smokers. Support for comprehensive smoke-free policies was positively associated with knowledge about the harm of SHS. Respondents who worked in a smoke-free worksite or who frequented smoke-free indoor entertainment places were more likely to support comprehensive smoking restriction in bars and restaurants.

CONCLUSION

Considerable support for smoke-free policies exists in these six large cities in China. Greater public education about the dangers of SHS may further increase support. Experiencing the benefits of smoke-free indoor entertainment places and/or workplaces increases support for these policies and suggests that some initial smoke-free policy implementation may hasten the diffusion of these public health policies.

Plasticity of the GABA(A) receptor subunit cassette in response to stressors in reactive versus resilient mice

GABA(A) functioning has been implicated in anxiety and depressive disorders. In this regard, we suggested that in addition to analyzing GABA(A) and the subunits that comprise the GABA(A) receptor, it might be profitable to assess the coordinated expression of subunits that comprise the GABA(A) receptor cassette. We demonstrate that certain subunits within stress-sensitive brain regions were higher in stressor reactive BALB/cByJ than in hardy C57BL/6ByJ mice, and that a chronic, intermittent, variable stressor (6 days/week over 7 weeks) differentially influenced subunit expression in these strains. Further, mRNA expression of GABA(A) subunits were highly coordinated (inter-correlated), and markedly altered by stressors, once again varying with brain region. At the central amygdala of BALB/cByJ mice the ordinarily high subunit inter-relations were reduced in acutely stressed mice, and this outcome was exacerbated with a chronic stressor. In C57BL/6ByJ mice subunit inter-relations were lower than in BALB/cByJ mice; the acute stressor increased subunit organization, which returned to control levels with following a chronic stressor. The profile of amygdala subunit inter-relations was recapitulated in a step-down behavioral test; anxiety was increased by acute and chronic stressors in BALB/cByJ mice, but in the C57BL/6ByJ strain the elevated anxiety associated with an acute stressor was not apparent after chronic stressor treatment. The anxiety could be dissociated from apparent anhedonia (reflected by free sucrose consumption) where the preference for sucrose was reduced by an acute stressor, but this outcome was more pronounced following a chronic stressor, especially in BALB/cByJ mice. These findings support the view that analyses involving subunit organization, rather than just differences in absolute levels, may be expedient in assessing GABA(A) functioning in stressor-related psychological disturbances.

Heritability of metabolic syndrome traits among healthy younger adults: a population based study in China

OBJECTIVE To estimate heritability of metabolic syndrome traits among healthy younger adults in a human population in China, and examine potential sex differences in heritability and parental effect on metabolic syndrome traits. METHODS Using offspring-parent regression, we estimated heritability (h(2)) of metabolic syndrome traits based on 452 child-parent triads identified from a population based random survey on metabolic syndrome among people over 15 years of age in Guangzhou, China. RESULTS Body mass index (BMI), cholesterol, high density lipoprotein cholesterol (HDL-C), low density lipoprotein cholesterol (LDL-C), fasting plasma glucose (FPG) and waist circumference (waist-C) were more heritable (h(2), 0.42-0.545), whereas systolic blood pressure (SBP), diastolic blood pressure (DBP), and triglycerides (TG) were less heritable (h(2), 0.14-0.28). Sons had pronounced increases in heritability for all traits over daughters, particularly for cholesterol (0.653 vs 0.356), FPG (0.602 vs 0.313), LDL-C (0.521 vs 0.329), and TG (0.395 vs 0.187). Offspring-mother seemed to have a higher heritability in every trait except FPG (0.67 vs 0.794) than offspring-father, most notably for DBP (0.308 vs 0.122), SBP (0.288 vs 0.146), TG (0.387 vs 0.239) and waist-C (0.581 vs 0.354). CONCLUSION We estimated the heritability of metabolic syndrome traits in a human population based on a unique population based offspring-parent sample from China, and found important evidence that the maternal and paternal effects on these traits are different and the sex difference in heritability is pronounced.

Mutations in the LDL receptor gene in four Chinese homozygous familial hypercholesterolemia phenotype patients

BACKGROUND AND AIMS

Familial hypercholesterolemia (FH) is an autosomal dominant disorder of lipoprotein metabolism caused by mutations in the low-density lipoprotein receptor (LDL-R) gene, leading to elevated levels of cholesterol and an increased risk of coronary heart disease. In this article, from four homozygous FH phenotype probands we identified disease causing mutations and analyzed the relationship between genotype and phenotype.

METHODS AND RESULTS

DNA sequencing identified five LDL-R point mutations in four unrelated families. We found a novel homozygous mutation (C210R), a homozygous mutation at W462X, a compound heterozygous mutation of C122Y and T383I, and a G>A intron 3 splice site homozygous mutation. The functional alteration caused by the novel C210R mutation was confirmed by FACS analysis. Four probands have high low-density lipoprotein cholesterol (LDL-C) levels, ranging from 14.65 to 27.66 mmol/L. Their heterozygous parents had relatively low levels. B-mode ultrasound supplemented by Doppler was used to examine aortic/mitral valve structural alterations and carotid intima-media thickness (ITM) in all probands. The ITM values were between 1.2 and 2.3mm, much higher than the normal value of <0.8mm.

CONCLUSION

Our data demonstrated that all the probands were associated with severe hypercholesterolemia, thick carotid IMT and a low CFVR (coronary flow velocity reserve) value. The novel mutation (C120Y) is a disease causing mutation.

Selenium for preventing Kashin-Beck osteoarthropathy in children: a meta-analysis

OBJECTIVE

To assess the efficacy of selenium supplementation for prevention of Kashin-Beck Osteoarthropathy in children.

METHODS

We searched eight electronic databases and seven journals (upto July 2007) to identify randomized controlled trials (RCTs) and prospective non-RCTs comparing selenium supplementations with placebo or no intervention for preventing Kashin-Beck disease (KBD). The methodological qualities of included studies were assessed according to the guidelines of Cochrane Handbook for Systematic Reviews of Interventions for RCTs and the method described by Deeks et al. for non-RCTs. Outcomes were presented as Peto-odds ratios (Peto-ORs) with 95% confidence intervals (95% CIs) based on fixed effect model. The number needed to treat (NNT) was calculated. Meta-regression was also conducted to explore the possible impacts of potential confounding variables (place of study, age, selenium form, etc.) of included trials on the incidence of KBD.

RESULTS

Five RCTs and 10 non-RCTs were included in this review. The methodological quality of included studies was low. The pooled Peto-OR and NNT favoring selenium supplement was 0.13 (95% CI: 0.04-0.47) and 21 in RCTs, and 0.16 (95% CI: 0.09-0.30) and 26 in non-RCTs. Meta-regression indicated that the effect of potential confounding variables on KBD incidence was not statistically significant. One trial reported the side effects of nausea and vomiting in the process of selenium supplementation.

CONCLUSIONS

Current evidence supports the benefits of selenium supplementation for prevention of KBD in children. However, the evidence was limited by potential biases and confounders. Large, well-designed trials are still needed.

Lead in housing paints: an exposure source still not taken seriously for children lead poisoning in China

After prohibitions on lead gasoline additives, which have proved to be a public health accomplishment world wide, many countries focus on other exposure source of children lead poisoning. Removing lead from paints is one of the important measures. Although there have been regulatory limits on lead in paints in China, evidence reported in this article indicates that lead-based paints were very common in new paints available for housing and in existing residential paints. Twenty-nine of 58 new paint samples (50%) had lead content equal to or exceeding 600 ppm, including 14 (24%) equal to or exceeding 5000 ppm. The highest sample contained 153,000 ppm lead, about 15% of the paint weight. Thirty-two new paints (55%) contained "soluble" lead exceeding 90 ppm, the current lead limit on paints in China. Of the existing paints, 16 of 28 samples of existing paint (57%) collected from 24 kindergartens and primary schools had lead concentrations equal to or exceeding 600 ppm, including six samples (21%) equal to or exceeding 5000 ppm. The highest concentration sample contained 51,800 ppm lead, accounting for 5.2% of the paint weight. It has been shown in many areas that paint lead is a major exposure source for lead poisoning in children. This is particularly true after the phasing out of lead from gasoline. Effective limitation on lead content in new paint, and lead hazard control measures directed towards existing paint, could reduce children blood lead levels (BLLs). There has been a lead standard for paints in China since 1986 and a stricter limit was introduced in recent years. Governments should take it seriously and enforce regulations, commit a long-term challenge to eliminate paint lead as it is the threat to current and the next generation.

Nutrition and children's respiratory health in Guangzhou, China

OBJECTIVE

To investigate the role of nutrition in children's respiratory health in subjects participating in a study on air pollution and respiratory health.

STUDY DESIGN

Cross-sectional survey.

METHODS

The relationships between consumption of fresh fruit, vegetables and milk and pulmonary function (forced expiratory volume in 1 s, FEV(1)) and respiratory symptoms (phlegm with cold, phlegm without cold, cough with cold, and cough without cold) were examined in 2228 children (age 10.07+/-0.86 years) in Guangzhou, China.

RESULTS

A positive association was found between consumption of leafy vegetables and lung function in children. Subjects with the highest consumption of leafy vegetables had significant higher FEV(1) values than subjects who ate leafy vegetables less than once per week (1.68 l vs 1.56 l; P=0.047). Children with high consumption of fresh fruit and milk had higher lung function values than children with low consumption, although the differences were not statistically significant. Milk consumption was a protective factor for phlegm with cold, cough with cold, and cough without cold [odds ratio (OR) 0.62, 95% confidence interval (CI) 0.39-0.97; OR 0.53, 95% CI 0.36-0.79; OR 0.43, 95% CI 0.21-0.92, respectively, in the highest intake group]. Consumption of vegetables was a protective factor for cough with cold (P for trend=0.003) and cough without cold (P for trend=0.028). Consumption of fresh fruit was marginally associated with reduced prevalence of respiratory symptoms.

CONCLUSIONS

This study suggests that dietary nutrients are important protective factors for children's respiratory health. Following-up these children may provide more evidence to confirm these associations.

An antibiotic complex from Lysobacter enzymogenes strain C3: antimicrobial activity and role in plant disease control

Lysobacter enzymogenes C3 is a bacterial biological control agent that exhibits antagonism against multiple fungal pathogens. Its antifungal activity was attributed in part to lytic enzymes. In this study, a heat-stable antifungal factor (HSAF), an antibiotic complex consisting of dihydromaltophilin and structurally related macrocyclic lactams, was found to be responsible for antagonism by C3 against fungi and oomycetes in culture. HSAF in purified form exhibited inhibitory activity against a wide range of fungal and oomycetes species in vitro, inhibiting spore germination, and disrupting hyphal polarity in sensitive fungi. When applied to tall fescue leaves as a partially-purified extract, HSAF at 25 mug/ml and higher inhibited germination of conidia of Bipolaris sorokiniana compared with the control. Although application of HSAF at 12.5 mug/ml did not reduce the incidence of conidial germination, it inhibited appressorium formation and suppressed Bipolaris leaf spot development. Two mutant strains of C3 (K19 and DeltaNRPS) that were disrupted in different domains in the hybrid polyketide synthase-nonribosomal peptide synthetase gene for HSAF biosynthesis and had lost the ability to produce HSAF were compared with the wild-type strain for biological control efficacy against Bipolaris leaf spot on tall fescue and Fusarium head blight, caused by Fusarium graminearum, on wheat. Both mutant strains exhibited decreased capacity to reduce the incidence and severity of Bipolaris leaf spot compared with C3. In contrast, the mutant strains were as efficacious as the wild-type strain in reducing the severity of Fusarium head blight. Thus, HSAF appears to be a mechanism for biological control by strain C3 against some, but not all, plant pathogenic fungi.

Biosynthesis of sphinganine-analog mycotoxins

Sphinganine-analog mycotoxins (SAMT) are polyketide-derived natural products produced by a number of plant pathogenic fungi and are among the most economically important mycotoxins. The toxins are structurally similar to sphinganine, a key intermediate in the biosynthesis of ceramides and sphingolipids, and competitive inhibitors for ceramide synthase. The inhibition of ceramide and sphingolipid biosynthesis is associated with several fatal diseases in domestic animals and esophageal cancer and neural tube defects in humans. SAMT contains a highly reduced, acyclic polyketide carbon backbone, which is assembled by a single module polyketide synthase. The biosynthesis of SAMT involves a unique polyketide chain-releasing mechanism, in which a pyridoxal 5'-phosphate-dependent enzyme catalyzes the termination, offloading and elongation of the polyketide chain. This leads to the introduction of a new carbon-carbon bond and an amino group to the polyketide chain. The mechanism is fundamentally different from the thioesterase/cyclase-catalyzed polyketide chain releasing found in bacterial and other fungal polyketide biosynthesis. Genetic data suggest that the ketosynthase domain of the polyketide synthase and the chain-releasing enzyme are important for controlling the final product structure. In addition, several post-polyketide modifications have to take place before SAMT become mature toxins.

Expression of ksdD gene encoding 3-ketosteroid-?1-dehydrogenase from Arthrobacter simplex in Bacillus subtilis

AIMS

To improve KSDH enzyme activity and the transformation level for androst-4-ene-3,17-dione.

METHODS AND RESULTS

3-ketosteroid-Delta(1)-dehydrogenase gene from Arthrobacter simplex was expressed in Bacillus subtilis under the control of P43 promoter. The molecular weight of expressed enzyme was about 55 kDa by SDS-PAGE analysis. The activities of intracellular and extracellular soluble enzymes examined by spectrophotometrical method were 110 +/- 0.5 mU mg(-1) and 15 +/- 0.6 mU mg(-1) of protein, respectively. The transformation rate of androst-4-ene-3,17-dione was 45.3% in the B. subtilis recombinant cells.

CONCLUSIONS

The enzyme activity of KSDH expressed in B. subtilis was improved about 30-fold compared with that of Arthrobacter simplex, and the transformation level of androst-4-ene-3,17-dione by the B. subtilis recombinant cells was improved about 10-fold.

SIGNIFICANCE AND IMPACT OF THE STUDY

The recombinant B. subtilis cells used for biotransformation of steroids provide a new method for production of steroid medicine. The time required for transformation of B. subtilis is much shorter than that of other bacteria, which means it will have wider usage in biopharmaceutical industry.

Hyperintensity of the precentral gyral subcortical white matter and hypointensity of the precentral gyrus on fluid-attenuated inversion recovery: variation with age and implications for the diagnosis of amyotrophic lateral sclerosis

BACKGROUND AND PURPOSE

Hyperintensity of the subcortical white matter (SWM) of the precentral gyrus and hypointensity of the precentral gyrus gray matter (PGGM) on fluid-attenuated inversion recovery (FLAIR) are described as potentially useful diagnostic findings in amyotrophic lateral sclerosis (ALS). A detailed study of the prevalence of these findings in various age groups has not been described.

METHODS

One hundred twenty-two patients underwent axial FLAIR brain examinations as part of either hearing loss or tinnitus evaluation. Examinations were randomly selected to reflect an even spread through the decades from ages 15 to 78 years and were reviewed by 2 readers, blinded to patient's age and sex, for the presence/absence of the above 2 signs. If SWM hyperintensity was present, it was graded as intense as caudate nucleus (grade 1) or insula (grade 2).

RESULTS

We identified 32 cases of grade 1 and 5 cases of grade 2 SWM hyperintensity, and 28 cases of PGGM hypointensity. Both signs showed significant Spearman correlation with increasing age (r = 0.55, P < .001 for grade 1, r = 0.45, P < .001 for grade 2 SWM hyperintensity, r = 0.45, P < .001 for PGGM hypointensity). Analysis of variance showed there was a significant difference between the different age groups (P < .001) for both signs. Grading of the SWM and PGGM signals were highly reproducible with very good interobserver agreement (r = 0.88, P < .001, and r = 0.97, P < .001, respectively).

CONCLUSION

This study suggests a statistically significant relationship between increasing age and the frequency of precentral gyrus SWM hyperintensity and PGGM hypointensity on FLAIR, and reinforces previous reports that these signs can be seen in patients who do not have ALS.

Hyperintensity of the middle cerebellar peduncles on fluid-attenuated inversion recovery imaging: variation with age and implications for the diagnosis of multiple system atrophy

BACKGROUND AND PURPOSE

T2 hyperintensity of the middle cerebellar peduncle (MCP) is described in a number of diseases, including multiple system atrophy (MSA). We hypothesize that mild MCP hyperintensity on fluid-attenuated inversion recovery (FLAIR) imaging can be a normal finding. To our knowledge, a detailed study of the prevalence of this finding in various age groups with the FLAIR sequence has not been described.

METHODS

One hundred twenty-two patients underwent an axial FLAIR examination of the brain as part of either a hearing loss or tinnitus work-up (ie, to exclude an acoustic neuroma or a retrocochlear cause). Subjects aged 15-78 years were included to reflect an even spread through the decades and were divided into 6 age groups. A radiologist and an MR imaging fellow graded the examinations subjectively, blinded to age: 0 for normal or 1 for the presence of MCP hyperintensity if the increased signal intensity was greater than that of adjacent pons and cerebellar white matter. Spearman rank correlation test of MCP hyperintensity with age and analysis of variance (ANOVA) were performed.

RESULTS

Of 122 patients, we identified 17 with MCP FLAIR hyperintensity. None of these patients had a clinical condition that could cause MCP hyperintensity. MCP hyperintensity did not show a statistically significant correlation with age (r = 0.05, P = .62). Patients were divided into 6 age groups, and ANOVA showed no statistically significant difference in the incidence of MCP hyperintensity between different age groups (P = .95). However, results were highly reproducible with excellent interobserver correlation (r = 0.97, P < .001).

CONCLUSIONS

Mild MCP FLAIR hyperintensity can occur normally, and this finding shows no relationship with age.

Patterns of nucleotide misincorporations during enzymatic amplification and direct large-scale sequencing of ancient DNA

Whereas evolutionary inferences derived from present-day DNA sequences are by necessity indirect, ancient DNA sequences provide a direct view of past genetic variants. However, base lesions that accumulate in DNA over time may cause nucleotide misincorporations when ancient DNA sequences are replicated. By repeated amplifications of mitochondrial DNA sequences from a large number of ancient wolf remains, we show that C/G-to-T/A transitions are the predominant type of such misincorporations. Using a massively parallel sequencing method that allows large numbers of single DNA strands to be sequenced, we show that modifications of C, as well as to a lesser extent of G, residues cause such misincorporations. Experiments where oligonucleotides containing modified bases are used as templates in amplification reactions suggest that both of these types of misincorporations can be caused by deamination of the template bases. New DNA sequencing methods in conjunction with knowledge of misincorporation processes have now, in principle, opened the way for the determination of complete genomes from organisms that became extinct during and after the last glaciation.

Functional replacement of the ketosynthase domain of FUM1 for the biosynthesis of fumonisins, a group of fungal reduced polyketides

The genetic manipulation of the biosynthesis of fungal reduced polyketides has been challenging due to the lack of knowledge on the biosynthetic mechanism, the difficulties in the detection of the acyclic, non-aromatic metabolites, and the complexity in genetically manipulating filamentous fungi. Fumonisins are a group of economically important mycotoxins that contaminate maize-based food and feed products worldwide. Fumonisins contain a linear dimethylated C18 chain that is synthesized by Fum1p, which is a single module polyketide synthase (PKS). Using a genetic system that allows the specific manipulation of PKS domains in filamentous fungus Fusarium verticillioides, we replaced the KS domain of fumonisin FUM1 with the KS domain of T-toxin PKS1 from Cochliobolus heterostrophus. Although PKS1 synthesizes different polyketides, the F. verticillioides strain carrying the chimeric PKS produced fumonisins. This represents the first successful domain swapping in PKSs for fungal reduced polyketides and suggests that KS domain alone may not be sufficient to control the product's structure. To further test if the whole fumonisin PKS could be functionally replaced by a PKS that has a similar domain architecture, we replaced entire FUM1 with PKS1. This strain did not produce any fumonisin or new metabolites, suggesting that the intrinsic interactions between the intact PKS and downstream enzymes in the biosynthetic pathway may play a role in the control of fungal reduced polyketides.

The brain mapping on reinforcement acupuncture stimulation at ST36 (zusanli) evidenced by fMRI

To characterize the brain mapping on reinforcement acupuncture stimulation at ST36 (zusanli), and to discuss the mechanisms of acupuncture to treat diseases. fMRI was performed on 26 healthy Chinese student volunteers. Sixteen subjects were acupunctured at the acupoint ST36, while 10 others at sham-acupoint (lateral from ST36 about 3 cm). The fMRI studies were performed using a gradient echo-EPI sequence. Brain mapping were generated using GE Functool program. Cerebral blood flow and correlation coefficient (CC) of ROl were analyzed. Stimulation at the right ST36 elicited 13 brain functional areas, and 10 of these areas were the same with the sham-acupoint group. However, only the temporal gyrus was specificity while by using reinforcement manual acupuncture (MA) at ST36 (Fisher's Exact test, P=0.022), and the contralateral hemisphere activation was prominent (McNemer test, P=0.020). Our results support the theory of acupuncture about meridian distribution overlapping on the whole body. The special transmission channel of meridian may exists, and it may be consist of spinal nerve and autonomic nerve. However, our results may oppose the theory concerning on stomach meridian walking lateral.

Partitioning invertase between a dilute water solution and generated droplets

Water droplets or mist occur naturally in the air at seashores. These water droplets carry inorganic and organic substances from the sea to the land via the air, creating fertile land in sandy coastal areas (1). The same phenomenon occurs in an air-fluidized bed bioreactor (2). In an air-fluidized bed reactor, proteins can be transferred from the bioreactor semisolid bulk phase to an enriched droplet phase. This protein transfer process (droplet fractionation) can be experimentally simulated by shaking a separatory funnel containing a dilute solution of a given protein, which can be an enzyme like invertase. The created droplets become richer in invertase (protein) than that of the original dilute solution. The droplets can then be coalesced by trapping them and recovering the concentrated protein in the new liquid phase. Typically, in such a droplet fractionation process a collected enzyme can be degraded in its ability to catalyze a chemical reaction. In this article, we explore whether the initial solution pH control variable can be adjusted to minimize the decrease of enzyme activity in this process. The protein droplet recovery problem is one in which the recovered amount of desired protein (enzyme) in the droplet is maximized, subject to the minimization of the enzyme activity loss. The partition coefficient, which is the ratio between the protein concentration in the droplets and the residual solution, is maximized at approx 4.8 and occurs at pH 3.0. Here, the partition coefficient for invertase decreases as the initial solution pH increases, between pH 3.0 and 8.0. Interestingly, the initial solution surface tension seems to be inversely proportional to the partition coefficient. The partition coefficient reaches a maximum value at a surface tension value of approx 63 mN/m at pH 3.0. The enzymatic activity of the initial, the residual, and the droplet solutions all decrease as the bulk solution pH increases. A decrease of enzymatic activity was observed in the residual bulk solution when compared with that in the initial bulk solution at all pH levels. Also, up to 90% of the invertase activity was lost in the droplets when compared to the initial bulk solution.

Enhanced DNA-dependent protein kinase activity in Sjogren's syndrome B cells

OBJECTIVE

To examine the stress response, including the role of DNA-dependent protein kinase (DNA-PK), in B cells from Sjögren's syndrome (SS) patients.

METHODS

B-cell lines were exposed to gamma radiation and then postincubated to allow inducible stress functions to develop. The magnitude of the DNA damage response was monitored with respect to DNA-PK phosphorylation of a p53 peptide, defence protein levels (Ku, DNA-PK catalytic subunit, ATM, p21 and p53) and flow cytometric determination of cell cycle phases and apoptosis.

RESULTS

B cells from SS patients, compared with healthy controls, displayed enhancement of two stress functions in undamaged cells: DNA-PK kinase activity and apoptosis. In addition, SS showed enhanced cell cycle arrest in gamma-irradiated cells.

CONCLUSIONS

Strong kinase activity of DNA-PK, functioning not only in a DNA damage response but also in immunoglobulin gene rearrangement, may be an important component of the heightened stress response displayed by SS cells. In combination with recent reports, our data indicate that constitutional hyper-reactivity to danger signals is a basic pathogenetic factor in SS.

Measurement of bubble size distribution in protein foam fractionation column using capillary probe with photoelectric sensors

Bubble size is a key variable for predicting the ability to separate and concentrate proteins in a foam fractionation process. It is used to characterize not only the bubble-specific interfacial area but also coalescence of bubbles in the foam phase. This article describes the development of a photoelectric method for measuring the bubble size distribution in both bubble and foam columns for concentrating proteins. The method uses a vacuum to withdraw a stream of gas-liquid dispersion from the bubble or foam column through a capillary tube with a funnel-shaped inlet. The resulting sample bubble cylinders are detected, and their lengths are calculated by using two pairs of infrared photoelectric sensors that are connected with a high-speed data acquisition system controlled by a microcomputer. The bubble size distributions in the bubble column 12 and 1 cm below the interface and in the foam phase 1 cm above the interface are obtained in a continuous foam fractionation process for concentrating ovalbumin. The effects of certain operating conditions such as the feed protein concentration, superficial gas velocity, liquid flow rate, and solution pH are investigated. The results may prove to be helpful in understanding the mechanisms controlling the foam fractionation of proteins.

Serotonergic genes and suicidality

Several lines of evidence indicate that abnormalities in the functioning of the central serotonergic system are involved in the pathogenesis of depressive illness and suicidal behavior. Studies have shown that the number of brain and platelet serotonin transporter binding sites are reduced in patients with depression and in suicide victims, and that the density of 5-HT2A receptors is increased in brain regions of depressed in suicide victims and in platelets of depressed suicidal patients. Genes that code for proteins, such as tryptophan hydroxylase, 5-HT transporter, and 5-HT2A receptor, involved in regulating serotonergic neurotransmission, have thus been major candidate genes for association studies of suicide and suicidal behavior. Recent studies by our group and by others have shown that genetic variations in the serotonin-system-related genes might be associated with suicidal ideation and completed suicide. We have shown that the 102 C allele in 5-HT2A receptor gene was significantly associated with suicidal ideation (chi2 = 8.5. p < .005) in depressed patients. Patients with a 102 C/C genotype had a significantly higher mean HAMD item #3 score (indication of suicidal ideation) than T/C or T/7 genotype patients. Our results suggest that the 102T/C polymorphism in 5-HT2A receptor gene is primarily associated with suicidal ideation in patients with major depression and not with depression itself. We also found that the 5-HT transporter gene S/L polymorphism was significantly associated with completed suicide. The frequency of the L/L genotype in depressed suicide victims was almost double of that found in control group (48.6% vs. 26.2%). The odds ratio for the L allele was 2.1 (95% CI 1.2-3.7). The association between polymorphism in serotonergic genes and suicidality supports the hypothesis that genetic factors can modulate suicide risk by influencing serotonergic activity.

Cdc42 interacts with the exocyst and regulates polarized secretion

Polarized delivery and incorporation of proteins and lipids to specific domains of the plasma membrane is fundamental to a wide range of biological processes such as neuronal synaptogenesis and epithelial cell polarization. The exocyst complex is specifically localized to sites of active exocytosis and plays essential roles in secretory vesicle targeting and docking at the plasma membrane. Sec3p, a component of the exocyst, is thought to be a spatial landmark for polarized exocytosis. In a search for proteins that regulate the localization of the exocyst in the budding yeast Saccharomyces cerevisiae, we found that certain cdc42 mutants affect the polarized localization of the exocyst proteins. In addition, we found that these mutant cells have a randomized protein secretion pattern on the cell surface. Biochemical experiments indicated that Sec3p directly interacts with Cdc42 in its GTP-bound form. Genetic studies demonstrated synthetically lethal interactions between cdc42 and several exocyst mutants. These results have revealed a role for Cdc42 in exocytosis. We propose that Cdc42 coordinates the vesicle docking machinery and the actin cytoskeleton for polarized secretion.

The biosynthetic gene cluster for the anticancer drug bleomycin from Streptomyces verticillus ATCC15003 as a model for hybrid peptide-polyketide natural product biosynthesis

The hybrid peptide-polyketide backbone of bleomycin (BLM) is assembled by the BLM megasynthetase that consists of both nonribosomal peptide synthetase (NRPS) and polyketide synthase (PKS) modules. BlmIX/BlmVIII/BlmVII constitute a natural hybrid NRPS/PKS/NRPS system, serving as a model for both hybrid NRPS/PKS and PKS/NRPS systems. Sequence analysis and functional comparison of domains and modules of BlmIX/BlmVIII/BlmVII with those of nonhybrid NRPS and PKS systems suggest that (1) the same catalytic sites appear to be conserved in both hybrid NRPS-PKS and nonhybrid NRPS or PKS systems, with the exception of the KS domains in the hybrid NRPS/PKS systems that are unique; (2) specific interpolypeptide linkers may play a critical role in intermodular communication to facilitate transfer of the growing intermediates between the interacting NRPS and/or PKS modules; and (3) posttranslational modification of the BLM megasynthetase has been accomplished by a single PPTase with a broad substrate specificity toward the apo forms of both acyl carrier proteins (ACPs) and peptidyl carrier proteins (PCPs).

Synchronization of separation and determination based on multichannel mode-filtered light detection with capillary electrophoresis

A novel method for the synchronization of separation and determination is described, in which a mode-filtered light detector is used as an online detector in capillary electrophoresis. An instrument is described which has been developed for this purpose. The round capillary used in conventional capillary electrophoresis is replaced by an annular column, which is constructed from a naked optical fibre inserted into a fused-silica capillary. In fact, the annular electrophoresis column itself forms part of the mode-filtered light sensor. Along the side of the annular column are several detection channels for gathering and transmitting the mode-filtered light to a charge-coupled device (CCD). Every channel provides information on the sample from the point at which it is located. Using capillary isotachophoresis incorporating the annular column, the analytes in a sample containing alanine (10.0 mM) and glycine (9.7 mM) were simultaneously separated and determined using multichannel mode-filtered light detection with a detection limit of 1.5 mM.

Selective protection of mitogenically stimulated human lymphocytes but not leukemic cells from cytosine arabinoside-induced apoptosis by LY294002, a phosphoinositol-3 kinase inhibitor

Most malignant tumors have a defect in the Rb pathway that allows them to proliferate autonomously, unrestricted by the availability of mitogens and growth factors. This defect preconditions tumor cells to be less sensitive to inhibitors of growth factor receptors and/or signal transduction pathways that arrest normal cells, predominantly in G0/1. Strategies were proposed, therefore, to combine cytotoxic agents with such inhibitors in order to selectively arrest normal host cells in a relatively resistant part of the cycle and thereby protect them during chemotherapy with agents targeting proliferating cells. The present study was designed to explore whether inhibition of phosphatidylinositol-3 kinase (PI3K), one of the pivotal kinases involved in signal transduction essential for cell proliferation can be considered in these strategies. Indeed, proliferation of phytohemagglutinin stimulated human lymphocytes was prevented at 5 microM concentration of LY294002 (LY), a PI3K inhibitor, whereas several-times higher (> or =20 microM) concentrations of LY were needed to affect proliferation of leukemic HL-60, Molt-4, or Jurkat cells. LY prevented the exit of lymphocytes from G0 concomitant with the suppression of induction of cyclins D2, D3 and E, and phosphorylation of pRb. G0/1 lymphocytes, that were initially stimulated in the absence of LY, were also inhibited from proliferating following exposure to LY. The arrest of lymphocytes by LY was reversible and, after its removal, the cells asynchronously re-entered the cell cycle. LY, at a concentration of 5-20 microM, protected lymphocytes from apoptosis induced by ara-C but offered no protection at all to Jurkat cells treated under identical conditions. The data suggest that inhibitors of PI3K such as LY may be considered in strategies designed to shield normal cells from the cytotoxicity of chemotherapy by transiently arresting them in the cycle. An additional advantage of LY was the suppression of the protein level and activity of PKB/Akt, a kinase that, through the phosphorylation of the proapoptotic molecule BAD, protects cells from apoptosis. Because this LY-induced suppression was stronger in Jurkat cells (>70%) than in lymphocytes (20%), the proapoptotic effects of PKB/Akt down-regulation appear to be selective towards tumor cells.

[Studies on correlation between protonation and tautomerism and luminescence characteristics of quinolone]

The fluorescence characteristics of 8 kinds of quinolone in different pH medium were studied. Rules of wavelength and intensity of the fluorescence in different pH medium were discovered. The correlation between the protonation, tautomerism and luminescence characteristics of quinolone are studied. It is found that in pH 6-8 or 2-4 there are two luminescence species. By this, the new view is represented that the change of luminescence characteristics is arised from the protonation and tautomerism of quinolones in different pH medium and the material point of luminescence developed in equilibrium system of tautomerism. Additionally, the correlation between the protonation, tautomerism and luminescence is further discussed.

CYP83b1 is the oxime-metabolizing enzyme in the glucosinolate pathway in Arabidopsis

CYP83B1 from Arabidopsis thaliana has been identified as the oxime-metabolizing enzyme in the biosynthetic pathway of glucosinolates. Biosynthetically active microsomes isolated from Sinapis alba converted p-hydroxyphenylacetaldoxime and cysteine into S-alkylated p-hydroxyphenylacetothiohydroximate, S-(p-hydroxyphenylacetohydroximoyl)-l-cysteine, the next proposed intermediate in the glucosinolate pathway. The production was shown to be dependent on a cytochrome P450 monooxygenase. We searched the genome of A. thaliana for homologues of CYP71E1 (P450ox), the only known oxime-metabolizing enzyme in the biosynthetic pathway of the evolutionarily related cyanogenic glucosides. By a combined use of bioinformatics, published expression data, and knock-out phenotypes, we identified the cytochrome P450 CYP83B1 as the oxime-metabolizing enzyme in the glucosinolate pathway as evidenced by characterization of the recombinant protein expressed in Escherichia coli. The data are consistent with the hypothesis that the oxime-metabolizing enzyme in the cyanogenic pathway (P450ox) was mutated into a "P450mox" that converted oximes into toxic compounds that the plant detoxified into glucosinolates.

[Characteristics of N2O emissions from vegetal soils on Fildes peninsula, Antarctica]

The N2O fluxes from the vegetal soils were first measured on the Fildes peninsula, Antarctica, and the total N2O emission was also estimated in the summer 2 months. The daily variations of N2O fluxes appeared single-peak trend under the sunshine or rainy weather conditions but they were irregular under the snow weather conditions and inconsistent with the atmospheric temperatures. The seasonal variations of the N2O fluxes were affected by the temperature and rainfall. The conditions during the transitions between dry and wet seasons improved the N2O emission. The total N2O emissions from moss and lichen soils were 3.7152 kg and 2.5344 kg, respectively. It follows that the vegetal soils are the sources for the atmospheric N2O on the Fildes peninsula, Antarctica.

Cloning and characterization of a phosphopantetheinyl transferase from Streptomyces verticillus ATCC15003, the producer of the hybrid peptide-polyketide antitumor drug bleomycin

BACKGROUND

Phosphopantetheinyl transferases (PPTases) catalyze the posttranslational modification of carrier proteins by the covalent attachment of the 4'-phosphopantetheine (P-pant) moiety of coenzyme A to a conserved serine residue, a reaction absolutely required for the biosynthesis of natural products including fatty acids, polyketides, and nonribosomal peptides. PPTases have been classified according to their carrier protein specificity. In organisms containing multiple P-pant-requiring pathways, each pathway has been suggested to have its own PPTase activity. However, sequence analysis of the bleomycin biosynthetic gene cluster in Streptomyces verticillus ATCC15003 failed to reveal an associated PPTase gene.

RESULTS

A general approach for cloning PPTase genes by PCR was developed and applied to the cloning of the svp gene from S. verticillus. The svp gene is mapped to an independent locus not clustered with any of the known NRPS or PKS clusters. The Svp protein was overproduced in Escherichia coli, purified to homogeneity, and shown to be a monomer in solution. Svp is a PPTase capable of modifying both type I and type II acyl carrier proteins (ACPs) and peptidyl carrier proteins (PCPs) from either S. verticillus or other Streptomyces species. As compared to Sfp, the only 'promiscuous' PPTase known previously, Svp displays a similar catalytic efficiency (k(cat)/K(m)) for the BlmI PCP but a 346-fold increase in catalytic efficiency for the TcmM ACP.

CONCLUSIONS

PPTases have recently been re-classified on a structural basis into two subfamilies: ACPS-type and Sfp-type. The development of a PCR method for cloning Sfp-type PPTases from actinomycetes, the recognition of the Sfp-type PPTases to be associated with secondary metabolism with a relaxed carrier protein specificity, and the availability of Svp, in addition to Sfp, should facilitate future endeavors in engineered biosynthesis of peptide, polyketide, and, in particular, hybrid peptide-polyketide natural products.