Variations in metabolite profiles of serum coronas produced around PEGylated liposomal drugs by surface property

Understanding biomolecular coronas that spontaneously occur around nanocarriers (NCs) in biological fluids is critical to nanomedicine as the coronas influence the behaviors of NCs in biological systems. In contrast to extensive investigations of protein coronas over the past decades, understanding of the coronas of biomolecules beyond proteins, e.g., metabolites, has been rather limited despite such biochemicals being ubiquitously involved in the coronas, which may influence the bio-nano interactions and thus exert certain biological impacts. In this study, serum biomolecular coronas, in particular the coronas of metabolites including lipids, around PEGylated doxorubicin-loaded liposomes with different surface property were investigated. The surface properties of liposomal drugs varied in terms of surface charge and PEGylation density by employing different ionic lipids such as DOTAP and DOPS and different concentrations of PEGylation lipids in liposome formulation. Using the liposomal drugs, the influence of the surface property on the serum metabolite profiles in the coronas was traced for target molecules of 220 lipids and 88 hydrophilic metabolites. From the results, it was found that metabolites rather than proteins mainly constitute the serum coronas on the liposomal drugs. Most of the serum metabolites were found to be retained in the coronas but with altered abundances. Depending on their class, lipids exhibited a different dependence on the surface property. However, overall, lipids appeared to favor corona formation on more negatively charged and PEGylated surfaces. Hydrophilic metabolites also exhibited a similar propensity for corona formation. This study on the surface dependence of metabolite corona formation provides a fundamental contribution toward attaining a comprehensive understanding of biomolecular coronas, which will be critical to the development of efficient nanomedicine.

Size Dependence Unveiling the Adsorption Interaction of High-Density Lipoprotein Particles with PEGylated Gold Nanoparticles in Biomolecular Corona Formation

Apolipoproteins have been often found to be highly enriched in the serum protein coronas produced on various engineered nanoparticles (NPs), which is also known to greatly influence the behaviors of protein corona NPs in the biological systems. As most of the apolipoproteins in blood are associated with lipoproteins, it suggests the active involvement of lipoproteins in the formation of biomolecular coronas on NPs. However, the interactions of lipoprotein complexes with NPs in the corona formation have been rarely understood. In this study, to obtain insights into the interactions, the formation of biomolecular coronas of high-density lipoproteins (HDLs) on the PEGylated gold NPs (PEG-AuNPs) of various sizes (20-150 nm dia.) was investigated as a model system. The results of this study revealed a noticeable size dependence, which is a drastic increase in the affinity of HDL for larger NPs and thus less-curved NP surfaces. For example, only a few HDLs per NP, which correspond to 5% surface coverage, were found to constitute the hard coronas of HDLs on 20 nm PEG-AuNPs, whereas 73% surface coverage was assessed for larger 150 nm PEG-AuNPs. However, the relative affinities of HDL and apolipoprotein A-1 (APOA1) examined in competition with human serum albumin exhibited the opposite size dependences, which suggests that the adsorption of HDLs is not driven by the constituent protein, APOA1. In fact, the total strength of non-covalent intermolecular interactions between a HDL particle and a NP relies on the physical contact between the two particles, which thus depends on the varying curvatures of spherical NPs in this case. Therefore, it was concluded that it is whole HDL complex that interacts with the spherical PEG-AuNPs in the initial stage of adsorption toward biomolecular coronas, which is unveiled by the distinct size dependence observed in this study.

Nafamostat Mesilate Attenuates Ischemia-Reperfusion-Induced Renal Injury

BACKGROUND

It has been reported that nafamostat mesilate (NM) inhibits inflammatory injury via inhibition of complement activation in ischemic heart, liver, and intestine. However, it is unclear if NM also inhibits apoptosis in ischemia-reperfusion (IR)-injured kidney. We therefore investigated whether NM attenuates IR renal injury that involves inhibition of apoptosis.

METHODS

HK-2 cells and male C57BL/6 mice were used for this study. C57Bl/6 mice were divided into 4 groups: sham, NM (2 mg/kg) + sham, IR injury (IR injury; reperfusion 27 minutes after clamping of both the renal artery and vein), and NM + IR injury. Kidneys were harvested 24 hours after IR injury, and functional and molecular parameters were evaluated. For in vitro studies, HK-2 cells were incubated for 6 hours with mineral paraffin oil to induce hypoxic injury, and then treated with various doses of NM to evaluate the antiapoptotic effects.

RESULTS

Blood urea nitrogen, serum creatinine levels, and renal tissue injury scores in NM + IR-injured mice were significantly lower than those of control IR mice (all P < .01). NM significantly improved cell survival in hypoxic HK-2 cells (P < .01), significantly decreased renal Bax expression (P < .05), and increased renal Bcl-2 protein levels in IR kidneys and hypoxic HK-2 cells compared with those of the sham and control groups. The numbers of terminal deoxynucleotide transferase-mediated dUTP nick-end labeling- and 8-oxo-2'-deoxyguanosine-positive cells were significantly lower in NM + IR-injured kidneys compared with those in control IR-injured mice (P < .05); NM treatment decreased the expression of inducible and endothelial nitric oxide synthase in IR-injured mice (P < .05).

CONCLUSIONS

NM ameliorates IR renal injury via inhibition of apoptosis by, at least in part, lowering nitric oxide overproduction, reducing Bax, and increasing Bcl-2.

Abstract P4-09-21: Dual expression of aquaporin 3 and 5 in patients with early breast cancer

Background: We reported separately that AQP5 or AQP3 expression in tumor tissue may predict survival after surgery for the specific types of early breast cancer (EBC). However, there is no definitive evidence for the role of dual expression of the two AQPs. Therefore, the current study focused the association and its prognostic impact of their tumoral expressions in the same patients.

Patients and Methods: AQP3 and AQP5 expressions were investigated on the basis of the immunohistochemistry of tissue microarray specimens from 447 EBC patients who underwent surgery between 2003 and 2008 as described in previous studies. Patients were divided into 4 subgroups based on AQP3 and AQP5 expressions: group1 for (-/-), group2 for (-/+), group 3 for (+/-), and group 4 for (+/+), respectively.

Results: Among 477 patients, the number of patients for each group was as follows: group 1 (n=193, 43.2%), group 2 (n=74, 16.6%), group3 (n=110, 24.6%) and group 4 (n=70, 15.7%), respectively. In the current study a positive correlation was identified between AQP3 and 5 expressions (P=0.017 by a χ2- test) in particular for HER2- overexpressing and ER-positive tumors (P=0.009 and 0.044, respectively). Multivariate survival analysis showed that dual expression of AQP3 and AQP5 was a negative prognostic factor for relapse-free or distant disease-free survival for patients with HER2-overexpressing EBC (HR=3.107 and 3.683; P=0.043 and 0.027, respectively), statistically more prominent compared in case with AQP3 expression alone (HR=3.137 and 2.784; P=0.036 and 0.070, respectively).

Conclusion: Dual expression of AQP3 and AQP5 in tumor tissue may be considered as a potential prognostic marker in patients with HER2-overexpressing EBC after curative surgery.

Citation Format: Lee SJ, Chae YS, Kwon TJ, Chung JH, Lee J, Jung JH, Kim WW, Park HY, Jeong JY, Park S-H, Park S. Dual expression of aquaporin 3 and 5 in patients with early breast cancer. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P4-09-21.

Clinical significance of subclinical varicocelectomy in male infertility: systematic review and meta-analysis

Recent meta-analysis by the Cochrane collaboration concluded that treatment of varicocele may improve an infertile couple's chance of pregnancy. However, there has been no consensus on the management of subclinical varicocele. Therefore, we determine the impact of varicocele treatment on semen parameters and pregnancy rate in men with subclinical varicocele. The randomised controlled trials that assessed the presence and/or treatment of subclinical varicocele were included for systematic review and meta-analysis. Random effect model was used to calculate the weighted mean difference of semen parameters and odds ratio of pregnancy rates. Seven trials with 548 participants, 276 in subclinical varicocelectomy and 272 in no-treatment or clomiphene citrate subjects, were included. Although there was also no statistically significant difference in pregnancy rate (OR 1.29, 95% CI 0.99-1.67), surgical treatment resulted in statistically significant improvements on forward progressive sperm motility (MD 3.94, 95% CI 1.24-6.65). However, the evidence is not enough to allow final conclusions because the quality of included studies is very low and further research is needed.

Associations between Cerebral Embolism and Carotid Intraplaque Hemorrhage during Protected Carotid Artery Stenting

BACKGROUND AND PURPOSE

Carotid artery stent placement in patients with intraplaque hemorrhage remains controversial because of the incidence of cerebral embolism after the procedure. The purpose of this study is to determine if intraplaque hemorrhage is a significant risk factor for cerebral embolism during carotid artery stent placement.

MATERIALS AND METHODS

This prospective study assessed 94 consecutive patients with severe carotid stenosis. These patients underwent preprocedural carotid MR imaging and postprocedural DWI after carotid artery stent placement. Intraplaque hemorrhage was defined as the presence of high signal intensity within the carotid plaque that was >200% of the signal from the adjacent muscle on MPRAGE. We then analyzed the incidence of postprocedural ipsilateral ischemic events on DWI and primary outcomes within 30 days of carotid artery stent placement.

RESULTS

Forty-three patients (45.7%) had intraplaque hemorrhage on an MPRAGE image. There was no significant difference in the incidence of postprocedural ipsilateral ischemic events and primary outcomes between the intraplaque hemorrhage and non-intraplaque hemorrhage group. However, postprocedural ipsilateral ischemic events were more frequently observed in the symptomatic group (17/41 [41.5%]) than in the asymptomatic group (8/53 [15.1%]; P = .005).

CONCLUSIONS

Intraplaque hemorrhage was not a significant risk factor for cerebral embolism during carotid artery stent placement in patients with severe carotid stenosis. Symptomatic patients should receive more careful treatment during carotid artery stent placement because of the higher risk of postprocedural ipsilateral ischemic events.

Effect of Korean Red Ginseng extraction conditions on antioxidant activity, extraction yield, and ginsenoside Rg1 and phenolic content: optimization using response surface methodology

Background

Extraction conditions greatly affect composition, as well as biological activity. Therefore, optimization is essential for maximum efficacy.

Methods

Korean Red Ginseng (KRG) was extracted under different conditions and antioxidant activity, extraction yield, and ginsenoside Rg1 and phenolic content evaluated. Optimized extraction conditions were suggested using response surface methodology for maximum antioxidant activity and extraction yield.

Results

Analysis of KRG extraction conditions using response surface methodology showed a good fit of experimental data as demonstrated by regression analysis. Among extraction factors, such as extraction solvent and extraction time and temperature, ethanol concentration greatly affected antioxidant activity, extraction yield, and ginsenoside Rg1 and phenolic content. The optimal conditions for maximum antioxidant activity and extraction yield were an ethanol concentration of 48.8%, an extraction time 73.3 min, and an extraction temperature of 90°C. The antioxidant activity and extraction yield under optimal conditions were 43.7% and 23.2% of dried KRG, respectively.

Conclusion

Ethanol concentration is an important extraction factor for KRG antioxidant activity and extraction yield. Optimized extraction conditions provide useful economic advantages in KRG development for functional products.

A genetic variation in microRNA target site of KRT81 gene is associated with survival in early-stage non-small-cell lung cancer

BACKGROUND

MicroRNAs (miRNAs) have a key role in carcinogenesis through negative regulation of their target genes. Therefore, genetic variations in miRNAs or their target sites may affect miRNA-mRNA interactions, thereby result in altered expression of target genes. This study was conducted to investigate the associations between single-nucleotide polymorphisms (SNP) located in the miRNA target sites (poly-miRTSs) and survival of patients with early-stage non-small-cell lung cancer (NSCLC).

METHODS

Using public SNP database and miRNA target sites prediction program, 354 poly-miRTSs were selected for genotyping. Among these, 154 SNPs applicable to Sequenom's MassARRAY platform were investigated in 357 patients. A replication study was carried out on an independent patient population (n = 479). Renilla luciferase assay and reverse transcription-polymerase chain reaction were conducted to examine functional relevance of potentially functional poly-miRTSs.

RESULTS

Of the 154 SNPs analyzed in a discovery set, 14 SNPs were significantly associated with survival outcomes. Among these, KRT81 rs3660G>C was found to be associated with survival outcomes in the validation cohort. In the combined analysis, patients with the rs3660 GC + CC genotype had a significantly better overall survival compared with those with GG genotype [adjusted hazard ratio (aHR) for OS, 0.65; 95% confidence interval (CI) 0.50-0.85; P = 0.001]. An increased expression of the reporter gene for the C allele of rs3660 compared with the G allele was observed by luciferase assay. Consistently, the C allele was associated with higher relative expression level of KRT81 in tumor tissues.

CONCLUSION

The rs3660G>C affects KRT81 expression and thus influences survival in early-stage NSCLC. The analysis of the rs3660G>C polymorphism may be useful to identify patients at high risk of a poor disease outcome.

Characterization of Melanogenesis Inhibitory Constituents of Morus alba Leaves and Optimization of Extraction Conditions Using Response Surface Methodology

Melanin is a natural pigment that plays an important role in the protection of skin, however, hyperpigmentation cause by excessive levels of melatonin is associated with several problems. Therefore, melanogenesis inhibitory natural products have been developed by the cosmetic industry as skin medications. The leaves of Morus alba (Moraceae) have been reported to inhibit melanogenesis, therefore, characterization of the melanogenesis inhibitory constituents of M. alba leaves was attempted in this study. Twenty compounds including eight benzofurans, 10 flavonoids, one stilbenoid and one chalcone were isolated from M. alba leaves and these phenolic constituents were shown to significantly inhibit tyrosinase activity and melanin content in B6F10 melanoma cells. To maximize the melanogenesis inhibitory activity and active phenolic contents, optimized M. alba leave extraction conditions were predicted using response surface methodology as a methanol concentration of 85.2%; an extraction temperature of 53.2 °C and an extraction time of 2 h. The tyrosinase inhibition and total phenolic content under optimal conditions were found to be 74.8% inhibition and 24.8 μg GAE/mg extract, which were well-matched with the predicted values of 75.0% inhibition and 23.8 μg GAE/mg extract. These results shall provide useful information about melanogenesis inhibitory constituents and optimized extracts from M. alba leaves as cosmetic therapeutics to reduce skin hyperpigmentation.

Effectiveness and feasibility of assistant push on improvement of chest compression quality: a crossover study

PURPOSE

To improve the quality of chest compression (CC), we developed the assistant-push method, whereby the second rescuer pushes the back of the chest compressor during CC. We investigated the effectiveness and feasibility of assistant push in achieving and maintaining the CC quality.

METHODS

This was a randomized crossover trial in which 41 subjects randomly performed both of standard CC (single-rescuer group) and CC with instructor-driven assistant push (assistant-push group) in different order. Each session of CC was performed for 2 minutes using a manikin. Subjects were also assigned to both roles of chest compressor and assistant and together performed CC with subject-driven assistant push. Depth of CC, compression to recoil ratio, duty cycle, and rate of incomplete recoil were quantified.

RESULTS

The mean depth of CC (57.0 [56.0-59.0] vs 55.0 [49.5-57.5], P < .001) was significantly deeper, and the compression force (33.8 [29.3-36.4] vs 23.3 [20.4-25.3], P < .001) was stronger in the assistant-push group. The ratio of compression to recoil, duty cycle, and rate of incomplete chest recoil were comparable between the 2 groups. The CC depth in the single-rescuer group decreased significantly every 30 seconds, whereas in the assistant-push group, it was comparable at 60- and 90-second time points (P = .004). The subject assistant-push group performed CCs at a depth comparable with that of the instructor assistant-push group.

CONCLUSION

The assistant-push method improved the depth of CC and attenuated its decline, eventually helping maintain adequate CC depth over time. Subjects were able to feasibly learn assistant push and performed effectively.

Comparison of live performance and meat quality parameter of cross bred (korean native black pig and landrace) pigs with different coat colors

Five hundred and forty crossbred (Korean native black pig×Landrace) F₂ were selected at a commercial pig farm and then divided into six different coat color groups: (A: Black, B: White, C: Red, D: White spot in black, E: Black spot in white, F: Black spot in red). Birth weight, 21st d weight, 140th d weight and carcass weight varied among the different coat color groups. D group (white spot in black coat) showed a significantly higher body weight at each weigh (birth weight, 140th d weight and carcass weight) than did the other groups, whereas the C group (red coat color) showed a significantly lower body weight at finishing stage (140th d weight and carcass weight) compared to other groups. Meat quality characteristics, shear force, cooking loss and meat color were not significantly different among the different coat color groups, whereas drip loss was significantly higher in F than in other groups. Most blood characteristics were not significantly different among the different groups, except for the red blood cells.

Clinical impact of microscopic extrathyroidal extension in patients with papillary thyroid microcarcinoma treated with hemithyroidectomy

BACKGROUND

Pathologically confirmed microscopic extrathyroidal extension (ETE) is often identified after hemithyroidectomy in patients with papillary thyroid microcarcinoma (PTMC). Without the presence of microscopic ETE, these patients would be optimal candidates for hemithyroidectomy.

AIM

The present study aimed at evaluating the clinical impact of microscopic ETE on the recurrence of PTMC treated with hemithyroidectomy.

SUBJECTS AND METHODS

We compared the clinicopathological characteristics and 5-year outcomes for 262 PTMC patients without ETE and 86 with microscopic ETE who were treated with hemithyroidectomy between January 2004 and December 2010.

RESULTS

The mean tumour size was larger (0.67 vs. 0.54 cm, p < 0.001) and the proportion of tumours measuring ≥0.5 cm was higher (84.9 vs. 66.8 %, p = 0.001) in patients with microscopic ETE as compared with patients without ETE. Occult multifocal disease was more frequent in patients with microscopic ETE than in those without ETE (14.0 vs. 6.5 %, p = 0.030). However, the recurrence rate was not different between the two groups during the mean 55.8-month follow-up period. In addition, univariate and multivariate analyses revealed no meaningful association between recurrence and microscopic ETE in patients with PTMC treated with hemithyroidectomy.

CONCLUSIONS

Although microscopic ETE was associated with large tumour size and multifocal disease, its clinical impact on disease recurrence was not significant in PTMC patients treated with hemithyroidectomy. Therefore, microscopic ETE identified after hemithyroidectomy would not be an absolute indication for completion thyroidectomy in patients with PTMC.

Abstract P6-05-24: Expression of aquaporin 5 and its polymorphisms predict survival in patients with early breast cancer

Background. Our previous study showed the association of AQP5 up-regulation with cancer proliferation and migration in hormone-responsive breast cancer cell lines (MCF-7) and with unfavorable prognosis in a small number of patients with breast cancer. Accordingly, we analyzed the prognostic impact of AQP5 expression and polymorphisms in a large number of patients with early breast cancer (EBC).

Methods. AQP5 expression was investigated based on the immunohistochemistry of tissue microarray specimens from 609 EBC patients who underwent surgery between 2003 and 2008. We scored the staining intensity (IS) and percentage of positive tumor cells (PC). The genomic DNA was extracted from paraffin-embedded tumor-free tissue and then genotyped for 3 polymorphisms (rs3736309, rs1964676, and rs74091167) using the Sequenom Mass array system.

Results. Among the 3 polymorphisms, AQP5 overexpression (IS + PC ≥6) was correlated with AQP5 rs74091167 GG genotype. AQP5 overexpression and AQP5 rs74091167 was significantly associated with disease-free survival (DFS; P &lt; 0.001 and P = 0.021, respectively). Moreover, a multivariate survival analysis revealed that AQP5 overexpression and the GG genotype of AQP5 rs74091167 were significantly associated with DFS (HR = 2.026, 95% CI 1.058-3.881, P = 0.030; HR = 0.377, 95% CI 0.179-0.793, P = 0.010, respectively) adjusted to clinicopathological variables, which was prominent in patients with an ER/PgR-positive tumor.

Conclusions. Consistent with our previous study of breast cancer cell lines, AQP5 expression and AQP5 rs74091167 variant can be considered as a prognostic marker in patients with EBC after curative surgery. In the future, functional relevance of this variant needs to be clarified.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P6-05-24.

Environmental forcing shapes regional house mosquito synchrony in a warming temperate island

Seasonal changes in the abundance of exothermic organisms can be expected with climate change if warmer temperatures can induce changes in their phenology. Given the increased time for ectothermic organism development at lower temperatures, we asked whether population dynamics of the house mosquito, Culex pipiens s.l. (L.) (Diptera: Culicidae), in Jeju-do (South Korea), an island with a gradient of warming temperatures from north to south, showed differences in sensitivity to changes in temperature along the warming gradient. In addition, we asked whether synchrony, that is, the degree of concerted fluctuations in mosquito abundance across locations, was affected by the temperature gradient. We found the association of mosquito abundance with temperature to be delayed by 2 wk in the north when compared with the south. The abundance across all our sampling locations had a flat synchrony profile that could reflect impacts of rainfall and average temperature on the average of all our samples. Finally, our results showed that population synchrony across space can emerge even when abundance is differentially impacted by an exogenous factor across an environmental gradient.

The effects of climate change and globalization on mosquito vectors: evidence from Jeju Island, South Korea on the potential for Asian tiger mosquito (Aedes albopictus) influxes and survival from Vietnam rather than Japan

Background

Climate change affects the survival and transmission of arthropod vectors as well as the development rates of vector-borne pathogens. Increased international travel is also an important factor in the spread of vector-borne diseases (VBDs) such as dengue, West Nile, yellow fever, chikungunya, and malaria. Dengue is the most important vector-borne viral disease. An estimated 2.5 billion people are at risk of infection in the world and there are approximately 50 million dengue infections and an estimated 500,000 individuals are hospitalized with dengue haemorrhagic fever annually. The Asian tiger mosquito (Aedes albopictus) is one of the vectors of dengue virus, and populations already exist on Jeju Island, South Korea. Currently, colder winter temperatures kill off Asian tiger mosquito populations and there is no evidence of the mosquitos being vectors for the dengue virus in this location. However, dengue virus-bearing mosquito vectors can inflow to Jeju Island from endemic area such as Vietnam by increased international travel, and this mosquito vector's survival during colder winter months will likely occur due to the effects of climate change.

Methods and Results

In this section, we show the geographical distribution of medically important mosquito vectors such as Ae. albopictus, a vector of both dengue and chikungunya viruses; Culex pipiens, a vector of West Nile virus; and Anopheles sinensis, a vector of Plasmodium vivax, within Jeju Island, South Korea. We found a significant association between the mean temperature, amount of precipitation, and density of mosquitoes. The phylogenetic analyses show that an Ae. albopictus, collected in southern area of Jeju Island, was identical to specimens found in Ho Chi Minh, Vietnam, and not Nagasaki, Japan.

Conclusion

Our results suggest that mosquito vectors or virus-bearing vectors can transmit from epidemic regions of Southeast Asia to Jeju Island and can survive during colder winter months. Therefore, Jeju Island is no longer safe from vector borne diseases (VBDs) due to the effects of globalization and climate change, and we should immediately monitor regional climate change to identify newly emerging VBDs.

Wnt/β-catenin signaling and adipogenic genes are associated with intramuscular fat content in the longissimus dorsi muscle of Korean cattle

Intramuscular fat (IMF) is an important trait that influences beef quality. In two studies, we examined the possible involvement of the Wnt/β-catenin signaling pathway in IMF deposition in Korean cattle. In study 1, using a group of bulls and steers, we found that castration, a non-genetic factor, decreased (P < 0.01) the expression of both the WNT10B and CTNNB1 genes, whereas it increased the expression of the Wnt antagonist secreted frizzled-related proteins 4 (SFRP4, P < 0.001) and the adipogenic CCAAT/enhancer binding protein (C/EPB), alpha (CEBPA, P < 0.001) and peroxisome proliferator-activated receptor gamma (PPARG, P < 0.05) genes in longissimus dorsi muscle (LM) tissue. The WNT10B and CTNNB1 mRNA levels showed strong (P < 0.001) negative correlations (r = -0.68 and r = -0.73 respectively) with the IMF content, whereas the SFRP4, CEBPA and PPARG mRNA levels showed strong (P < 0.01) positive correlations (r = 0.70, 0.70 and 0.64 respectively) with the IMF content. Large variation still exists in the IMF content of steers, implying that genetic factors affect IMF deposition. Using a different group of steers, a correlation analysis in study 2 also showed that the expression of the WNT10B and CTNNB1 genes, and SFRP4 and adipogenic genes was negatively and positively associated with the IMF content respectively. Our findings suggest that downregulation of the Wnt/β-catenin signaling pathway genes, but upregulation of Wnt antagonist SFRP4 and adipogenic gene expression following castration, contributes to increased IMF deposition in the LM. Our results demonstrate that both non-genetic factors (castration) and genetic variation within the steer group affect the gene expression pattern of the Wnt/β-catenin signaling pathway.

Effect of thermal dissipation by adding graphene materials to surface coating of LED lighting module

The effect of thermal dissipation by adding graphene nano-platelets to two different commercially available thermal dissipation coatings (ceramic coating and powder coating) was studied. Steady state temperatures of each points of LED modules was monitored in a closed system, with an integral photo detection sphere where there is no external air flow. Having eliminated the contributions of thermal conduction and air flow convection, the module with a conventional heat dissipation coatings showed 8-16% enhancement of thermal dissipation compared to that of non-coated LED module. The addition of graphene is shown to have about 3% additional enhancement. By analyzing thermal resistance of each component of the LED module, the improved thermal conductivity of the graphene added coatings contributes to the enhancement of slight improvement with heat dissipation.

Severe dietary lysine restriction affects growth and body composition and hepatic gene expression for nitrogen metabolism in growing rats

Dietary lysine restriction may differentially affect body growth and lipid and nitrogen metabolism, depending on the degree of lysine restriction. This study was conducted to examine the effect of dietary lysine restriction on growth and lipid and nitrogen metabolism with two different degree of lysine restriction. Isocaloric amino acid-defined diets containing 1.4% lysine (adequate), 0.70% lysine (50% moderate lysine restriction) and 0.35% lysine (75% severe lysine restriction) were fed from the age of 52 to 77 days for 25 days in male Sprague-Dawley rats. The 75% severe lysine restriction increased (p < 0.05) food intake, but retarded (p < 0.05) growth, increased (p < 0.05) liver and muscle lipid contents and abdominal fat accumulation, increased (p < 0.05) blood urea nitrogen levels and mRNA levels of the serine-synthesizing 3-phosphoglycerate dehydrogenase gene, but decreased (p < 0.05) urea cycle arginase gene mRNA levels. In contrast, the 50% lysine restriction did not significantly (p > 0.05) affect body growth and lipid and nitrogen metabolism. Our results demonstrate that severe 75% lysine restriction has detrimental effects on body growth and deregulate lipid and nitrogen metabolism.

cAMP response element binding protein H mediates fenofibrate-induced suppression of hepatic lipogenesis

AIMS/HYPOTHESIS

Fenofibrate is a drug used to treat hyperlipidaemia that works by inhibiting hepatic triacylglycerol synthesis. Sterol regulatory element binding protein-1c (SREBP-1c) is a major regulator of the expression of genes involved in hepatic triacylglycerol synthesis. In addition, endoplasmic reticulum (ER)-bound transcription factor families are involved in the control of various metabolic pathways. Here, we show a novel function for an ER-bound transcription factor, cAMP response element binding protein H (CREBH), in fenofibrate-mediated inhibition of hepatic lipogenesis.

METHODS

The effects of fenofibrate and adenovirus-mediated Crebh (also known as Creb313) overexpression (Ad-Crebh) on hepatic SREBP-1c production and lipogenesis in vitro and in vivo were investigated. We also examined whether downregulation of endogenous hepatic Crebh by small interfering (si)RNA restores the fenofibrate effect on hepatic lipogenesis and SREBP-1c production. Finally, we examined the mechanism by which CREBH inhibits hepatic SREBP-1c production.

RESULTS

Fasting and fenofibrate treatment induced CREBH production and decreased SREBP-1c levels. Indeed, Ad-Crebh inhibited insulin- and liver X receptor agonist TO901317-induced Srebp-1c (also known as Srebf1) mRNA expression in cultured hepatocytes. Moreover, increased production of CREBH in the liver of mice following tail-vein injection of Ad-Crebh inhibited high-fat diet-induced hepatic steatosis through inhibition of Srebp-1c expression. The inhibition of endogenous Crebh expression by siRNA restored fenofibrate-induced suppression of Srebp-1c expression and hepatic lipid accumulation both in vitro and in vivo.

CONCLUSIONS/INTERPRETATION

These results show that fenofibrate decreases hepatic lipid synthesis through induction of CREBH. This study suggests CREBH as a novel negative regulator of SREBP-1c production and hepatic lipogenesis.

Discoloration characteristics of 3 major muscles from cattle during cold storage

Discoloration characteristics of 3 major muscles (LD, Longissimus dorsi; PM, Psoas major; SM, Semimemebranosus) from Korean native cattle (Hanwoo) were monitored during 7 d of cold storage at 4 degrees C. The muscles were obtained from 12 Hanwoo carcasses at 24 h postmortem. Meat color (CIE L*, a*, b*), myoglobin (Mb) concentration, chemical form, metmyoglobin (MetMb) reducing ability (MRA), mitochondria concentration, and thiobarbituric acid reactive substance (TBARS) were measured at 1, 3, 5, and 7 d of storage. Although there were no significant differences in CIE a* and b*-values between the 3 muscles at day 1, the values of PM muscle were significantly (P < 0.05) lower than those of LD and SM muscles at day 5 and 7. PM muscle showed a rapid decrease in the oxymyoglobin (OxyMb) and an increase in MetMb, which resulted in a significantly (P < 0.05) higher percentage of MetMb in PM muscle compared to LD and SM muscles. Also, the Mb and mitochondria concentration of PM muscle was significantly (P < 0.05) higher than those of LD and SM muscles. However, there were no significant differences in MRA, pH, or TBARS between the 3 muscles during 7 d of cold storage. It was concluded that rapid discoloration (that is, MetMb accumulation) in PM muscle of Hanwoo could be due to its higher contents of Mb and mitochondria.

A novel method of seminal vesicle preparation in isolated seminal vesicle experiments in the rat: ring preparation

In this study, we evaluated the efficacy of a novel method of seminal vesicle (SV) preparation-ring preparation method-in isolated SV experiments in the rat. Rat SVs were prepared as strips and rings and applied to organ baths. The relaxation responses by sodium nitroprusside or doxazosin and contractile responses by electrical field stimulation (EFS) were recorded in both groups. We compared the proportion of tissues that showed consistent responses to the stimuli-drug or EFS-in both groups. And magnitudes of the contractile or relaxation responses were also evaluated in the two groups. In strip preparations (n=20), six tissues (30%) showed stable responses to drugs and were regarded to be useful. However, in ring preparations (n=20), 13 tissues (65%) showed stable responses (P<0.001). Similarly, consistent contractile responses to the EFS were recorded in eight strips (40%) and 13 rings (65%) (n=20 in each group; P<0.05). The magnitudes of the relaxations by drugs were not different between the two methods (P=0.42) and the contractions by EFS were higher in ring preparations (P<0.05). The ring preparation seems to be better for responses to drugs and EFS compared with the strip preparations and, therefore, might be an alternative technique for in vitro SV experiments.

Effect of chilling temperature of carcass on breast meat quality of duck

An experiment was carried out to investigate whether variations in chill water temperature affect muscle shortening and meat quality in duck breast. Three chill water temperatures were applied to duck carcasses at 20 min postmortem for 30 min, including in ice water at 0 degrees C, in cold water at 10 degrees C, and in water at 20 degrees C. Results revealed that carcass temperatures were different (P < 0.05) at 50 and 120 min of postmortem with lower temperatures at the 0 degrees C treatment (P < 0.05). The pH over the first 24 h postmortem was not different (P > 0.05) among treatments, with the exception of 50 min postmortem. The pH of breast meat in the 0 degrees C treatment was higher (P < 0.05) than that of 20 degrees C treatment at 50 min postmortem (just after chilling). No other differences (P > 0.05) in pH existed among treatments. Drip loss, cooking loss, and moisture content were not different for breast meat samples that were chilled at different temperatures. Differences (P < 0.05) were found in CIE (L, a, and b) color values. Lightness (L) increased, whereas redness (a) decreased as the chill water temperature increased. Lower yellowness (b) was found in the breast meat samples at the 10 degrees C chill water temperature. However, shear force, sarcomere length, and protein solubility were not different (P > 0.05) among the breast meat samples chilled at different chill water temperatures. It may be concluded that chilling duck carcasses at different temperature ranges from 0 to 20 degrees C did not influence muscle shortening or meat quality, except in regard to breast meat color.

Effect of kimchi powder level and drying methods on quality characteristics of breakfast sausage

This study was conducted to determine the effect of the addition of kimchi powder on the quality characteristics of meat batter and breakfast sausage. Breakfast sausages were supplemented with freeze dried kimchi powder (FKP) or hot air dried kimchi powder (HKP) at levels of 1% (FKP-1 and HKP-1) or 2% (FKP-2 and HKP-2). The emulsion stability, cooking yield, and apparent viscosity in meat batters improved with increments of kimchi powder (p<0.05). Increased levels of kimchi powder in breakfast sausage decreased the L(∗) value, pH, and springiness, and increased the a(∗) value, b(∗) value, hardness, chewiness, and gumminess (p<0.05). Sensory evaluations indicated that a higher overall acceptability was attained when the kimchi powder was added to breakfast sausage at a level of 2%.

Structure determination of new analogues of vardenafil and sildenafil in dietary supplements

New analogues of vardenafil and sildenafil illegally added to dietary supplements were detected by high-performance liquid chromatography (HPLC) analysis with a photodiode array detector (PDA). These compounds were isolated and their structures elucidated by mass spectrometry (MS), infrared (IR) spectroscopy, one- and two-dimensional nuclear magnetic resonance (NMR). One of the new analogues given the trivial name pseudovardenafil (compound 1) was structurally elucidated and shown to be 1-[[3-(1,4-dihydro-5-methyl-4-oxo-7-propylimidazo[5,1-f][1,2,4]triazin-2-yl)-4-ethoxyphenyl]sulfonyl]-piperidine. It was a vardenafil analogue isolated from a dietary supplement capsule. Compared with vardenafil, the piperidine ring was substituted for the ethylpiperazine group. The second new analogue, trivially named hydroxyhongdenafil (compound 2), was separated from bulk powder used as a raw material for a dietary supplement. The piperazine and phenyl groups were connected through an acetyl group instead of a sulfonyl group, and hydroxyethylpiperazine was substituted for the methylpiperazine of sildenafil. It was structurally elucidated as 5-[2-ethoxy-5-[[4-(2-hydroxyethyl)-1-piperazinyl]acetyl]phenyl]-1,4-dihydro-1-methyl-3-propyl-7H-pyrazolo[4,3-d]pyrimidin-7-one.

Characterization of the TSU-PR1 cell line by chromosome painting and flow cytometry

TSU-PR1 was originally reported as a prostatic carcinoma cell line derived from a lymph node metastasis. Recently, however, this cell line was reported to be derived from T24 bladder carcinoma cells, and thus further definition of its origin is needed. Conventional cytogenetic study of TSU-PR1 showed aneuploidy, ranging from 65 to 86 chromosome with a modal number of 80, and with 10 marker chromosomes, thus conventional cytogenetics cannot be used to determine which chromosomes or regions of chromosomes are critical in cancer development and progression of this cell line. The present study was conducted to characterize genetic changes of the cell line using comparative genomic hybridization (CGH), fluorescence in situ hybridization (FISH), and flow cytometry. CGH results showed that green-to-red fluorescence ratios were within the range of 0.85-1.15, except for a few chromosomes, which reflected near tetraploidy in TSU-PR1. Flow cytometric analysis of TSU-PR1 revealed a DNA index of 3.46n, which is close to the 3.48n calculated from a modal number of 80. The copy numbers of chromosomes 4, 6, 7, 17, and 20 determined by the DNA index and the CGH analyses were 2.85 +/- 0.09, 3.22 +/- 0.77, 3.01 +/- 0.26, 4.05 +/- 0.44, and 4.99 +/- 0.48, respectively. These numbers are also in accordance with the chromosome copy numbers determined with FISH: 2.98 +/- 0.23, 2.91 +/- 0.44, 2.74 +/- 0.44, 3.93 +/- 0.38, and 5.05 +/- 0.78 for chromosomes 4, 6, 7, 17, and 20, respectively (P > 0.05).

Roles of FrxA and RdxA nitroreductases of Helicobacter pylori in susceptibility and resistance to metronidazole

The relative importance of the frxA and rdxA nitroreductase genes of Helicobacter pylori in metronidazole (MTZ) susceptibility and resistance has been controversial. Jeong et al. (J. Bacteriol. 182:5082--5090, 2000) had interpreted that Mtz(s) H. pylori were of two types: type I, requiring only inactivation of rdxA to became resistant, and type II, requiring inactivation of both rdxA and frxA to become resistant; frxA inactivation by itself was not sufficient to confer resistance. In contrast, Kwon et al. (Antimicrob. Agents Chemother. 44:2133--2142, 2000) had interpreted that resistance resulted from inactivation either of frxA or rdxA. These two interpretations were tested here. Resistance was defined as efficient colony formation by single cells from diluted cultures rather than as growth responses of more dense inocula on MTZ-containing medium. Tests of three of Kwon's Mtz(s) strains showed that each was type II, requiring inactivation of both rdxA and frxA to become resistant. In additional tests, derivatives of frxA mutant strains recovered from MTZ-containing medium were found to contain new mutations in rdxA, and frxA inactivation slowed MTZ-induced killing of Mtz(s) strains. Northern blot analyses indicated that frxA mRNA, and perhaps also rdxA mRNA, were more abundant in type II than in type I strains. We conclude that development of MTZ resistance in H. pylori requires inactivation of rdxA alone or of both rdxA and frxA, depending on bacterial genotype, but rarely, if ever, inactivation of frxA alone, and that H. pylori strains differ in regulation of nitroreductase gene expression. We suggest that such regulatory differences may be significant functionally during human infection.

Mouse-colonizing Helicobacter pylori SS1 is unusually susceptible to metronidazole due to two complementary reductase activities

In most strains of Helicobacter pylori, mutational inactivation of the rdxA (HP0954) gene, which encodes a nitroreductase that converts metronidazole (MTZ) from a harmless prodrug to a mutagenic and bacteriocidal product, is sufficient to make this pathogen resistant to clinically significant levels of MTZ. Here we report that SS1, a strain with the special ability to colonize mice, is unusual in being susceptible to very low concentrations of MTZ (0.5 microgram/ml) and in being especially difficult to mutate to MTZ resistance (Mtz(r)). These phenotypic traits were traced to expression in this strain of the normally quiescent H. pylori frxA gene (HP0642, an rdxA paralog) along with rdxA. Transformation tests using rdxA::cam and frxA::kan insertion mutant DNAs, with selection solely for the chloramphenicol and kanamycin resistance markers, and sequence analyses of frxA in spontaneous Mtz(r) derivatives of rdxA null mutant strains each showed that the development of Mtz(r) in SS1 required inactivation of both rdxA and frxA. Inactivation of either gene alone left SS1 susceptible to MTZ, although it was readily mutable from an MTZ-susceptible to an Mtz(r) phenotype. Reverse transcriptase PCR tests showed that frxA mRNA was at least 10-fold more abundant in SS1 than in reference strain 26695. It is proposed that these reductases play primarily nutritional roles during bacterial growth.

Metronidazole activation is mutagenic and causes DNA fragmentation in Helicobacter pylori and in Escherichia coli containing a cloned H. pylori RdxA(+) (Nitroreductase) gene

Much of the normal high sensitivity of wild-type Helicobacter pylori to metronidazole (Mtz) depends on rdxA (HP0954), a gene encoding a novel nitroreductase that catalyzes the conversion of Mtz from a harmless prodrug to a bactericidal agent. Here we report that levels of Mtz that partially inhibit growth stimulate forward mutation to rifampin resistance in rdxA(+) (Mtz(s)) and also in rdxA (Mtz(r)) H. pylori strains, and that expression of rdxA in Escherichia coli results in equivalent Mtz-induced mutation. A reversion test using defined lac tester strains of E. coli carrying rdxA(+) indicated that CG-to-GC transversions and AT-to-GC transitions are induced more frequently than other base substitutions. Alkaline gel electrophoretic tests showed that Mtz concentrations near or higher than the MIC for growth also caused DNA breakage in H. pylori and in E. coli carrying rdxA(+), suggesting that this damage may account for most of the bactericidal action of Mtz. Coculture of Mtz(s) H. pylori with E. coli (highly resistant to Mtz) in the presence of Mtz did not stimulate forward mutation in E. coli, indicating that the mutagenic and bactericidal products of Mtz metabolism do not diffuse significantly to neighboring (bystander) cells. Our results suggest that the widespread use of Mtz against other pathogens in people chronically infected with H. pylori may stimulate mutation and recombination in H. pylori, thereby speeding host-specific adaptation, the evolution of virulence, and the emergence of resistance against Mtz and other clinically useful antimicrobials.

Sequential inactivation of rdxA (HP0954) and frxA (HP0642) nitroreductase genes causes moderate and high-level metronidazole resistance in Helicobacter pylori

Helicobacter pylori is a human-pathogenic bacterial species that is subdivided geographically, with different genotypes predominating in different parts of the world. Here we test and extend an earlier conclusion that metronidazole (Mtz) resistance is due to mutation in rdxA (HP0954), which encodes a nitroreductase that converts Mtz from prodrug to bactericidal agent. We found that (i) rdxA genes PCR amplified from 50 representative Mtz(r) strains from previously unstudied populations in Asia, South Africa, Europe, and the Americas could, in each case, transform Mtz(s) H. pylori to Mtz(r); (ii) Mtz(r) mutant derivatives of a cultured Mtz(s) strain resulted from mutation in rdxA; and (iii) transformation of Mtz(s) strains with rdxA-null alleles usually resulted in moderate level Mtz resistance (16 microg/ml). However, resistance to higher Mtz levels was common among clinical isolates, a result that implicates at least one additional gene. Expression in Escherichia coli of frxA (HP0642; flavin oxidoreductase), an rdxA paralog, made this normally resistant species Mtz(s), and frxA inactivation enhanced Mtz resistance in rdxA-deficient cells but had little effect on the Mtz susceptibility of rdxA(+) cells. Strains carrying frxA-null and rdxA-null alleles could mutate to even higher resistance, a result implicating one or more additional genes in residual Mtz susceptibility and hyperresistance. We conclude that most Mtz resistance in H. pylori depends on rdxA inactivation, that mutations in frxA can enhance resistance, and that genes that confer Mtz resistance without rdxA inactivation are rare or nonexistent in H. pylori populations.

Murine pro-tumor necrosis factor expressed in Saccharomyces cerevisiae HF7c localizes to membrane/particulate

Tumor necrosis factor (TNF) is a cytokine that is produced by immune cells in response to bacterial and viral stimuli and plays important roles in various inflammatory diseases. TNF is produced as a membrane-bound precursor, which is then cleaved to release soluble mature protein. We expressed murine pro-TNF in Saccharomyces cerevisiae and examined processing and cellular localization of the recombinant protein. Yeast cells were transformed with an expression construct carrying the pro-TNF gene under the control of alcohol dehydrogenase promoter. Immunoblotting analysis of cell homogenate revealed expression of 26 kD pro-TNF in transformed cells. Upon centrifugation, pro-TNF transformed cells fractionated into the membrane/particulate. In a clone that expresses a high level of pro-TNF, mature 17 kD TNF was detected in the culture medium, although the amount was far smaller than that of cell-associated pro-TNF. Flow cytometric analysis of yeast spheroplasts demonstrated the presence of TNF on the cell surface. Our results show that pro-TNF expressed in yeast mainly resides in the cellular membrane with an orientation similar to that of pro-TNF produced in mammalian cells. Our data suggest that the transformed yeast cells can be used for the genetic analysis of pro-TNF processing machinery in immune cells.

Thiol-reactive metal compounds inhibit NF-kappa B activation by blocking I kappa B kinase

Gold compounds are used in the treatment of rheumatoid arthritis. NF-kappa B is a transcription factor implicated in the expression of many inflammatory genes. NF-kappa B is activated by signal-induced phosphorylation and subsequent degradation of inhibitory I kappa B (inhibitory protein that dissociates from NF-kappa B) proteins, and a multisubunit I kappa B kinase (IKK) has been identified previously. We tested the effect of various gold compounds on the activation of NF-kappa B and IKK in LPS-stimulated RAW 264.7 mouse macrophages. A lipophilic gold compound, auranofin, suppressed the LPS-induced increase of nuclear kappa B-binding activity, degradation of I kappa B proteins, and IKK activation. Auranofin also blocked IKK activation induced by TNF and PMA/ionomycin, suggesting that the target of auranofin action is common among these diverse signal pathways. In vitro IKK activity was suppressed by addition of hydrophilic gold compounds, such as aurothiomalate, aurothioglucose, and AuCl3. Other thiol-reactive metal ions such as zinc and copper also inhibited IKK activity in vitro, and induction of IKK in LPS-stimulated macrophages. In vitro IKK activity required the presence of reducing agent and was blocked by addition of thiol group-reactive agents. Two catalytic subunits of IKK complex, IKK alpha and IKK beta, were both inhibited by these thiol-modifying agents, suggesting the presence of a cysteine sulfhydryl group in these subunits, which is critical for enzyme activity. The antiinflammatory activity of gold compounds in the treatment of rheumatoid arthritis may depend on modification of this thiol group by gold.

Distinctiveness of genotypes of Helicobacter pylori in Calcutta, India

The genotypes of 78 strains of Helicobacter pylori from Calcutta, India (55 from ulcer patients and 23 from more-benign infections), were studied, with a focus on putative virulence genes and neutral DNA markers that were likely to be phylogenetically informative. PCR tests indicated that 80 to 90% of Calcutta strains carried the cag pathogenicity island (PAI) and potentially toxigenic vacAs1 alleles of the vacuolating cytotoxin gene (vacA), independent of disease status. This was higher than in the West (where cag PAI(+) vacAs1 genotypes are disease associated) but lower than in east Asia. The iceA2 gene was weakly disease associated in Calcutta, whereas in the West the alternative but unrelated iceA1 gene at the same locus is weakly disease associated. DNA sequence motifs of vacAm1 (middle region) alleles formed a cluster that was distinct from those of east Asia and the West, whereas the cagA sequences of Calcutta and Western strains were closely related. An internal deletion found in 20% of Calcutta iceA1 genes was not seen in any of approximately 200 strains studied from other geographic regions and thus seemed to be unique to this H. pylori population. Two mobile DNAs that were rare in east Asian strains were also common in Calcutta. About 90% of Calcutta strains were metronidazole resistant. These findings support the idea that H. pylori gene pools differ regionally and emphasize the potential importance of studies of Indian and other non-Western H. pylori populations in developing a global understanding of this gastric pathogen and associated disease.

Mode-locked Cr(2+):ZnSe laser

We describe active mode locking of a Cr(2+):ZnSe laser operating near 2.5 mum. The laser produces 4.4-ps transform-limited Gaussian-shaped pulses and produces 82 mW of average power.

Nuclear factor kappaB (NF-kappaB) pathway as a therapeutic target in rheumatoid arthritis

Rheumatoid arthritis (RA) is a chronic inflammatory disease characterized by persistent joint swelling and progressive destruction of cartilage and bone. Current RA treatments are largely empirical in origin and their precise mechanism of action is uncertain. Increasing evidence shows that chronic inflammatory diseases such as RA are caused by prolonged production of proinflammatory cytokines including tumor necrosis factor (TNF) and interleukin 1 (IL-1). The nuclear factor kappaB (NF-kappaB) plays an essential role in transcriptional activation of TNF and IL-1. NF-kappaB is induced by many stimuli including TNF and IL-1, forming a positive regulatory cycle that may amplify and maintain RA disease process. NF-kappaB and enzymes involved in its activation can be a target for anti-inflammatory treatment. Aspirin and sodium salicylate inhibit activation of NF-KB by blocking IkappaB kinase, a key enzyme in NF-kappaB activation. Glucocorticoids suppress expression of inflammatory genes by binding glucocorticoid receptor with NF-kappaB, and increasing expression of inhibitory protein of NF-kappaB, IkappaBalpha. Sulfasalazine and gold compounds also inhibit NF-kappaB activation. Continuing advances in our understanding of action mechanism of antirheumatic agents will benefit the future development of RA regimens with greater efficacy and less toxicity.

Helicobacter pylori with separate beta- and beta'-subunits of RNA polymerase is viable and can colonize conventional mice

The genes encoding the beta- and beta'-subunits of RNA polymerase (rpoB and rpoC respectively) are fused as one continuous open reading frame in Helicobacter pylori and in other members of this genus, but are separate in other bacterial taxonomic groups, including the closely related genus Campylobacter. To test whether this beta-beta' tethering is essential, we used polymerase chain reaction-based cloning to separate the rpoB and rpoC moieties of the H. pylori rpoB-rpoC fusion gene with a non-polar chloramphenicol resistance cassette containing a new translational start, and introduced this construct into H. pylori by electro-transformation. H. pylori containing these separated rpoB and rpoC genes in place of the native fusion gene produced non-tethered beta and beta' RNAP subunits, grew well in culture and colonized and proliferated well in conventional C57BL/6 mice. Thus, the extraordinary beta-beta' tethering is not essential for H. pylori viability and gastric colonization.

Tosylphenylalanine chloromethyl ketone inhibits TNF-alpha mRNA synthesis in the presence of activated NF-kappa B in RAW 264.7 macrophages

Serine proteinase inhibitors such as N-tosyl-L-phenylalanine chloromethyl ketone (TPCK) and N alpha-p-tosyl-L-lysine chloromethyl ketone (TLCK) were shown to inhibit production of tumour necrosis factor-alpha (TNF-alpha) in lipopolysaccharide (LPS)-activated RAW 264.7 macrophages. The proteinase inhibitors were also reported to inhibit activation of the transcription factor nuclear factor-kappa B (NF-kappa B) by blocking the signalling pathway for stimuli-induced phosphorylation of the inhibitory subunit (I kappa B alpha) and thus preventing its degradation. In RAW 264.7 cells TPCK and TLCK significantly suppressed LPS-induced increase in TNF-alpha mRNA, induction of nuclear kappa B-binding activity and degradation of I kappa B alpha. TPCK and TLCK effectively blocked TNF-alpha mRNA synthesis even when they were added after LPS stimulation. In these cells, however, the inhibitory modes of the two inhibitors were found to be different: while addition of TLCK suppressed I kappa B alpha degradation and reduced NF-kappa B activity, a comparable decrease in the nuclear kappa B-binding activity or in I kappa B alpha degradation was not observed in cells treated with TPCK. Our results show that TPCK inhibits LPS-induced TNF-alpha mRNA synthesis in the presence of activated NF-kappa B and suggests that mechanisms other than NF-kappa B activation are involved in the transcriptional regulation of the TNF-alpha gene.

Guanine-nucleotide binding and hydrolyzing kinetics of ORrab2, a rice small GTP-binding protein expressed in Escherichia coli

The ORrab2 gene encodes a GTP-binding protein of 23.169 kDa. The deduced amino acid sequence shows that ORrab2 has the motifs conserved among small GTP-binding proteins in plants and that it shares sequence identity with Atrab2 (93.0%), Hrab2 (85.2%), Hrab4 (51.9%), Hrab1 (46.2%), YPT (40.7%), Hrab3B (40.0%), Hrab3A (38.1%), SEC4 (38.1%), Hrab5 (34.3%) and Hrab6 (32.4%). To analyze the biochemical properties of this protein, an ORrab2 cDNA was overexpressed in Escherichia coli and the protein purified by Ni2+-nitrilotriacetic acid agarose and hydroxyapatite column chromatography. The molecular mass of the protein bearing a His-tag is approximately 28.2 kDa. The guanine-nucleotide binding and hydrolyzing activity of ORrab2 increased with non-ionic C12E10 (polyoxyethylene 10-lauryl ether) and ionic Chaps detergent treatment. ORrab2 bound maximally 1.03 mol of [gamma-35S]GTP[S]/mol of protein with a Kd value of 56.83 nM. The ratios k(off GDP)/k(off GTP) of ORrab2 were 3.63 for the control, 3.7 in the presence of C12E10, and 3.83 with Chaps, indicating that ORrab2 has a higher affinity for GTP than GDP. The rate (k(cat)) of Pi release against [gamma-32P]GTP bound ORrab2 in a steady state and the rate of hydrolysis of [gamma-32P]GTP (kGTPase) were calculated to be 432 x 10(-4) +/- 8 x 10(-4) min(-1) and 172 x 10(-4) +/- 2 x 10(-4) min(-1), respectively, in the presence of 0.1% C12E10 and 1 mM MgSO4.

Functional features of an ssi signal of plasmid pGKV21 in Escherichia coli

A single-strand initiation (ssi) signal was detected on the Lactococcus lactis plasmid pGKV21 containing the replicon of pWV01 by its ability to complement the poor growth of an M13 phage derivative (M13 delta lac182) lacking the complementary-strand origin in Escherichia coli. This ssi signal was situated at the 229-nucleotide (nt) DdeI-DraI fragment and located within the 109 nt upstream of the nick site of the putative plus origin. SSI activity is orientation specific with respect to the direction of replication. We constructed an ssi signal-deleted plasmid and then examined the effects of the ssi signal on the conversion of the single-stranded replication intermediate to double-stranded plasmid DNA in E. coli. The plasmid lacking an ssi signal accumulated much more plasmid single-stranded DNA than the wild-type plasmid did. Moreover, deletion of this region caused a great reduction in plasmid copy number or plasmid maintenance. These results suggest that in E. coli, this ssi signal directs its lagging-strand synthesis as a minus origin of plasmid pGKV21. Primer RNA synthesis in vitro suggests that E. coli RNA polymerase directly recognizes the 229-nt ssi signal and synthesizes primer RNA dependent on the presence of E. coli single-stranded DNA binding (SSB) protein. This region contains two stem-loop structures, stem-loop I and stem-loop II. Deletion of stem-loop I portion results in loss of priming activity by E. coli RNA polymerase, suggesting that stem-loop I portion is essential for priming by E. coli RNA polymerase on the SSB-coated single-stranded DNA template.

Chloroquine inhibits processing of tumor necrosis factor in lipopolysaccharide-stimulated RAW 264.7 macrophages

TNF, a potent immunoregulatory cytokine, is associated with inflammatory diseases such as rheumatoid arthritis, multiple sclerosis, and cerebral malaria when produced in excess. Antimalarial agents such as chloroquine and hydroxychloroquine have been used to treat some rheumatic diseases. Chloroquine was reported to inhibit production of TNF, although the underlying mechanism is poorly understood. In RAW 264.7 cells stimulated with LPS, addition of chloroquine at nontoxic concentrations did not inhibit induction of TNF mRNA and NF-kappaB activity. In the same cells, synthesis and steady state level of 26-kDa pro-TNF were also not significantly reduced by addition of chloroquine, while only small amount of 17-kDa mature TNF was detected in the medium. A pulse-chase experiment of pro-TNF produced in chloroquine-treated cells showed significant inhibition of processing of prohormone. Hydroxychloroquine showed similar inhibitory effect, whereas other lysosomal inhibitors such as ammonium chloride and methylamine had no effect on the production of TNF. Our results suggest that chloroquine inhibits production of TNF at the step of processing of membrane-bound pro-TNF to make soluble mature protein in a lysosome-independent manner.

Chloroquine inhibits processing of tumor necrosis factor in lipopolysaccharide-stimulated RAW 264.7 macrophages

TNF, a potent immunoregulatory cytokine, is associated with inflammatory diseases such as rheumatoid arthritis, multiple sclerosis, and cerebral malaria when produced in excess. Antimalarial agents such as chloroquine and hydroxychloroquine have been used to treat some rheumatic diseases. Chloroquine was reported to inhibit production of TNF, although the underlying mechanism is poorly understood. In RAW 264.7 cells stimulated with LPS, addition of chloroquine at nontoxic concentrations did not inhibit induction of TNF mRNA and NF-kappaB activity. In the same cells, synthesis and steady state level of 26-kDa pro-TNF were also not significantly reduced by addition of chloroquine, while only small amount of 17-kDa mature TNF was detected in the medium. A pulse-chase experiment of pro-TNF produced in chloroquine-treated cells showed significant inhibition of processing of prohormone. Hydroxychloroquine showed similar inhibitory effect, whereas other lysosomal inhibitors such as ammonium chloride and methylamine had no effect on the production of TNF. Our results suggest that chloroquine inhibits production of TNF at the step of processing of membrane-bound pro-TNF to make soluble mature protein in a lysosome-independent manner.

Molecular characterization of a rab-related small GTP binding protein cDNA from rice (Oryza sativa L. IR-36)

To study physiological roles of plant small GTP binding proteins, we isolated a cDNA clone (ORrab2) encoding the rab-related small GTP binding protein from rice (Oryza sativa L. IR-36) by using human cDNA rab2 as a probe. The deduced amino acid sequence of the ORrab2 gene shared all the conserved regions, important for GTPase/GTP binding activities, with those of other small GTP binding proteins. ORrab2 is a 1028 bp long cDNA, encodes a 23.2 kDa protein which shows 85.2% similarity on the amino acid sequence level to the Hrab2 protein, and was used as a probe. Through Southern and Northern blot analyses, we found that ORrab2 is a single copy gene and actively expressed at the stages of cell division and elongation. We investigated GTP binding abilities by a filter assay procedure. Deletion of a binding motif, GDTGVGKS, within an ORrab2 protein showed a significant decrease of GTP binding affinity, suggesting its important role in nucleotide binding.