bluuebunny/crossref_metadata_2025 huggingface dataset:
Acid shock of Listeria monocytogenes at low environmental temperatures induces prfA, epithelial cell invasion, and lethality towards Caenorhabditis elegans
Authors: Neuhaus Klaus , Satorhelyi Peter , Schauer Kristina , Scherer Siegfried , Fuchs Thilo M
Published: April 2013

Background

The saprophytic pathogen Listeria monocytogenes has to cope with a variety of acidic habitats during its life cycle. The impact of low-temperature coupled with pH decrease for global gene expression and subsequent virulence properties, however, has not been elucidated.

Results

qRT-PCR revealed for the first time a transient, acid triggered prfA induction of approximately 4-fold, 5.7-fold, 7-fold and 9.3-fold 60 to 90 min after acid shock of L. monocytogenes at 37°C, 25°C, 18°C, and 10°C, respectively. Comparable data were obtained for seven different L. monocytogenes strains, demonstrating that prfA induction under these conditions is a general response of L. monocytogenes. Transcriptome analysis revealed that the in vivo-relevant genes bsh, clpP, glpD, hfq, inlA, inlB, inlE, lisR, and lplA1 as well as many other genes with a putative role during infection are transiently induced upon acid shock conducted at 25°C and 37°C. Twenty-five genes repressed upon acid shock are known to be down regulated during intracellular growth or by virulence regulators. These data were confirmed by qRT-PCR of twelve differentially regulated genes and by the identification of acid shock-induced genes influenced by σB. To test if up regulation of virulence genes at temperatures below 37°C correlates with pathogenicity, the capacity of L. monocytogenes to invade epithelial cells after acid shock at 25°C was measured. A 12-fold increased number of intracellular bacteria was observed (acid shock, t = 60 min) that was reduced after adaptation to the level of the unshocked control. This increased invasiveness was shown to be in line with the induction of inlAB. Using a nematode infection assay, we demonstrated that Caenorhabditis elegans fed with acid-shocked L. monocytogenes exhibits a shorter time to death of 50% (TD50) of the worms (6.4 days) compared to infection with unshocked bacteria (TD50 = 10.2 days).

Conclusions

PrfA and other listerial virulence genes are induced by an inorganic acid in a temperature-dependent manner. The data presented here suggest that low pH serves as a trigger for listerial pathogenicity at environmental temperatures.
The Nocardia cyriacigeorgica GUH-2 genome shows ongoing adaptation of an environmental Actinobacteria to a pathogen’s lifestyle
Authors: Zoropogui Anthony , Pujic Petar , Normand Philippe , Barbe Valérie , Belli Patrick , Graindorge Arnault , Roche David , Vallenet David , Mangenot Sophie , Boiron Patrick , Rodriguez-Nava Véronica , Ribun Sebastien , Richard Yves , Cournoyer Benoit , Blaha Didier
Published: April 2013

Background

Nocardia cyriacigeorgicais recognized as one of the most prevalent etiological agents of human nocardiosis. Human exposure to these Actinobacteria stems from direct contact with contaminated environmental matrices. The full genome sequence ofN. cyriacigeorgicastrain GUH-2 was studied to infer major trends in its evolution, including the acquisition of novel genetic elements that could explain its ability to thrive in multiple habitats.

Results

N. cyriacigeorgicastrain GUH-2 genome size is 6.19 Mb-long, 82.7% of its CDS have homologs in at least another actinobacterial genome, and 74.5% of these are found inN. farcinica. AmongN. cyriacigeorgicaspecific CDS, some are likely implicated in niche specialization such as those involved in denitrification and RuBisCO production, and are found in regions of genomic plasticity (RGP). Overall, 22 RGP were identified in this genome, representing 11.4% of its content. Some of these RGP encode a recombinase and IS elements which are indicative of genomic instability. CDS playing part in virulence were identified in this genome such as those involved in mammalian cell entry or encoding a superoxide dismutase. CDS encoding non ribosomal peptide synthetases (NRPS) and polyketide synthases (PKS) were identified, with some being likely involved in the synthesis of siderophores and toxins. COG analyses showed this genome to have an organization similar to environmental Actinobacteria.

Conclusion

N. cyriacigeorgicaGUH-2 genome shows features suggesting a diversification from an ancestral saprophytic state. GUH-2 ability at acquiring foreign DNA was found significant and to have led to functional changes likely beneficial for its environmental cycle and opportunistic colonization of a human host.
Colonization strategies of Pseudomonas fluorescens Pf0-1: activation of soil-specific genes important for diverse and specific environments
Authors: Varivarn Katila , Champa Lindsey A , Silby Mark W , Robleto Eduardo A
Published: April 2013

Background

Pseudomonas fluorescens is a common inhabitant of soil and the rhizosphere environment. In addition to potential applications in biocontrol and bioremediation, P. fluorescens is of interest as a model for studying bacterial survival and fitness in soil. A previous study using in vivo expression technology (IVET) identified 22 genes in P. fluorescens Pf0-1 which are up-regulated during growth in Massachusetts loam soil, a subset of which are important for fitness in soil. Despite this and other information on adaptation to soil, downstream applications such as biocontrol or bioremediation in diverse soils remain underdeveloped. We undertook an IVET screen to identify Pf0-1 genes induced during growth in arid Nevada desert soil, to expand our understanding of growth in soil environments, and examine whether Pf0-1 uses general or soil type-specific mechanisms for success in soil environments.

Results

Twenty six genes were identified. Consistent with previous studies, these genes cluster in metabolism, information storage/processing, regulation, and ‘hypothetical’, but there was no overlap with Pf0-1 genes induced during growth in loam soil. Mutation of both a putative glutamine synthetase gene (Pfl01_2143) and a gene predicted to specify a component of a type VI secretion system (Pfl01_5595) resulted in a decline in arid soil persistence. When examined in sterile loam soil, mutation of Pfl01_5595 had no discernible impact. In contrast, the Pfl01_2143 mutant was not impaired in persistence in sterile soil, but showed a significant reduction in competitive fitness.

Conclusions

These data support the conclusion that numerous genes are specifically important for survival and fitness in natural environments, and will only be identified using in vivo approaches. Furthermore, we suggest that a subset of soil-induced genes is generally important in different soils, while others may contribute to success in specific types of soil. The importance of glutamine synthetase highlights a critical role for nitrogen metabolism in soil fitness. The implication of Type 6 secretion underscores the importance of microbial interactions in natural environments. Understanding the general and soil-specific genes will greatly improve the persistence of designed biocontrol and bioremediation strains within the target environment.
Impact of agr dysfunction on virulence profiles and infections associated with a novel methicillin-resistant Staphylococcus aureus (MRSA) variant of the lineage ST1-SCCmec IV
Authors: Ferreira Fabienne Antunes , Souza Raquel Rodrigues , de Sousa Moraes Bruno , de Amorim Ferreira Ana Maria , Américo Marco Antônio , Fracalanzza Sérgio Eduardo Longo , dos Santos Silva Couceiro José Nelson , Sá Figueiredo Agnes Marie
Published: April 2013

Background

A novel variant of the ST1-SCCmecIV methicillin-resistantStaphylococcus aureus(MRSA) lineage, mostly associated with nosocomial bloodstream infections (BSI), has emerged in Rio de Janeiro. Bacterial biofilm has been considered a major virulence factor in central venous catheter-associated BSI. The mechanisms involved in biofilm formation/accumulation are multifactorial and complex. Studies have suggested that biofilm production was affectedin vitroand vivo foragr-null mutants ofS. aureus.

Results

The impact of naturally occurring inhibition ofagrsignaling on virulence profiles and infections associated with the ST1 variant was investigated.agrdysfunction was detected in a significant percentage (13%) of the isolates with concomitant increase in biofilm accumulationin vitroandin vivo, and enhanced ability to adhere to and invade airway cells. The biofilm formed by these ST1 isolates wasica-independent and proteinaceous in nature. In fact, the improved colonization properties were paralleled by an increased expression of the biofilm-associated genesfnbA,spaandsasG. The transcription ofsarA, a positive regulator ofagr, was two-times reduced for theagr-dysfunctional MRSA. Remarkably, theagrinhibition was genetically stable. Indeed,agr-dysfunctional isolates succeed to colonize and cause both acute and chronic infections in hospitalized patients, and also to effectively accumulate biofilm in a mouse subcutaneous catheter implant model.

Conclusion

The ability ofagr-dysfunctional isolates to cause infections in humans and to form biofilm in the animal model suggests that therapeutic approaches based onagr-inactivation strategies are unlikely to be effective in controlling human-device infections caused by ST1 isolates. The increased biofilm accumulation associated with the acquisition of multiple antimicrobial resistant traits might have influenced (at least in part) the expansion of this USA400 related clone in our hospitals.
Silencing of Nicotiana benthamiana Neuroblastoma-Amplified Genecauses ER stress and cell death
Authors: Lee Jae-Yong , Sarowar Sujon , Kim Hee Seung , Kim Hyeran , Hwang Inhwan , Kim Young Jin , Pai Hyun-Sook
Published: April 2013

Background

Neuroblastoma Amplified Gene (NAG) was identified as a gene co-amplified with the N-myc gene, whose genomic amplification correlates with poor prognosis of neuroblastoma. Later it was found that NAG is localized in endoplasmic reticulum (ER) and is a component of the syntaxin 18 complex that is involved in Golgi-to-ER retrograde transport in human cells. Homologous sequences of NAG are found in plant databases, but its function in plant cells remains unknown.

Results

Nicotiana benthamania Neuroblastoma-Amplified Gene (NbNAG) encodes a protein of 2,409 amino acids that contains the secretory pathway Sec39 domain and is mainly localized in the ER. Silencing of NbNAG by virus-induced gene silencing resulted in growth arrest and acute plant death with morphological markers of programmed cell death (PCD), which include chromatin fragmentation and modification of mitochondrial membrane potential. NbNAG deficiency caused induction of ER stress genes, disruption of the ER network, and relocation of bZIP28 transcription factor from the ER membrane to the nucleus, similar to the phenotypes of tunicamycin-induced ER stress in a plant cell. NbNAG silencing caused defects in intracellular transport of diverse cargo proteins, suggesting that a blocked secretion pathway by NbNAG deficiency causes ER stress and programmed cell death.

Conclusions

These results suggest that NAG, a conserved protein from yeast to mammals, plays an essential role in plant growth and development by modulating protein transport pathway, ER stress response and PCD.
Genome-wide identification and functional analyses of calmodulin genes in Solanaceousspecies
Authors: Zhao Yuan , Liu Wei , Xu You-Ping , Cao Jia-Yi , Braam Janet , Cai Xin-Zhong
Published: April 2013

Background

Calmodulin (CaM) is a major calcium sensor in all eukaryotes. It binds calcium and modulates the activity of a wide range of downstream proteins in response to calcium signals. However, little is known about theCaMgene family inSolanaceousspecies, including the economically important species, tomato (Solanum lycopersicum), and the gene silencing model plant,Nicotiana benthamiana. Moreover, the potential function of CaM in plant disease resistance remains largely unclear.

Results

We performed genome-wide identification ofCaMgene families inSolanaceousspecies. Employing bioinformatics approaches, multiple full-lengthCaMgenes were identified from tomato,N. benthamianaand potato (S. tuberosum) genomes, with tomato having 6CaMgenes,N. benthamianahaving 7CaMgenes, and potato having 4CaMgenes. Sequence comparison analyses showed that three tomato genes,SlCaM3/4/5, two potato genesStCaM2/3, and two sets ofN. benthamianagenes,NbCaM1/2/3/4andNbCaM5/6,encode identical CaM proteins, yet the genes contain different intron/exon organization and are located on different chromosomes. Further sequence comparisons and gene structural and phylogenetic analyses reveal thatSolanaceousspecies gained a new group ofCaMgenes during evolution. These newCaMgenes are unusual in that they contain three introns in contrast to only a single intron typical of knownCaMgenes in plants. The tomatoCaM(SlCaM) genes were found to be expressed in all organs. Prediction of cis-acting elements in 5' upstream sequences and expression analyses demonstrated thatSlCaMgenes have potential to be highly responsive to a variety of biotic and abiotic stimuli. Additionally, silencing ofSlCaM2andSlCaM6altered expression of a set of signaling and defense-related genes and resulted in significantly lower resistance toTobacco rattle virusand the oomycete pathogen,Pythium aphanidermatum.

Conclusions

TheCaMgene families in theSolanaceousspecies tomato,N. benthamianaand potato were identified through a genome-wide analysis. All three plant species harbor a small set of genes that encode identical CaM proteins, which may manifest a strategy of plants to retain redundancy or enhanced quantitative gene function. In addition,Solanaceousspecies have evolved one new group ofCaMgenes during evolution.CaMgenes play important roles in plant disease resistance to a variety of pathogens.
Dipeptidyl peptidase IV inhibitor attenuates kidney injury in rat remnant kidney
Authors: Joo Kwon Wook , Kim Sejoong , Ahn Shin-young , Chin Ho Jun , Chae Dong-Wan , Lee Jeonghwan , Han Jin Suk , Na Ki Young
Published: April 2013

Background

The inhibition of dipeptidyl peptidase (DPP) IV shows protective effects on tissue injury of the heart, lung, and kidney. Forkhead box O (FoxO) transcriptional factors regulate cellular differentiation, growth, survival, the cell cycle, metabolism, and oxidative stress. The aims of this study were to investigate whether the DPP IV inhibitor sitagliptin could attenuate kidney injury and to evaluate the status of FoxO3a signaling in the rat remnant kidney model.

Methods

Rats were received two-step surgery of 5/6 renal mass reduction and fed on an oral dose of 200 mg/kg/day sitagliptin for 8 weeks. Before and after the administration of sitagliptin, physiologic parameters were measured. After 8 weeks of treatment, the kidneys were harvested.

Results

The sitagliptin treatment attenuated renal dysfunction. A histological evaluation revealed that glomerulosclerosis and tubulointerstitial injury were significantly decreased by sitagliptin. Sitagliptin decreased DPP IV activity and increased the renal expression of glucagon-like peptide-1 receptor (GLP-1R). The subtotal nephrectomy led to the activation of phosphatidylinositol 3-kinase (PI3K)-Akt and FoxO3a phosphorylation, whereas sitagliptin treatment reversed these changes, resulting in PI3K-Akt pathway inactivation and FoxO3a dephosphorylation. The renal expression of catalase was increased and the phosphorylation of c-Jun N-terminal kinase (JNK) was decreased by sitagliptin. Sitagliptin treatment reduced apoptosis by decreasing cleaved caspase-3 and −9 and Bax levels and decreased macrophage infiltration.

Conclusions

In rat remnant kidneys, DPP IV inhibitor attenuated renal dysfunction and structural damage. A reduction of apoptosis, inflammation and an increase of antioxidant could be suggested as a renoprotective mechanism together with the activation of FoxO3a signaling. Therefore, DPP IV inhibitors might provide a promising approach for treating CKD, but their application in clinical practice remains to be investigated.
Determinants of infant mortality in community of Gilgel Gibe Field Research Center, Southwest Ethiopia: a matched case control study
Authors: Dube Lamessa , Taha Mohammed , Asefa Henok
Published: April 2013

Background

Infant mortality accounts for almost 67 percent of under-five child mortality that occurs globally. An understanding of factors related to infant mortality is important to guide the development of focused and evidence-based health interventions to reduce infant deaths. But no community based studies have been conducted to identify determinants of infant mortality in Ethiopia for the past two decades. The purpose of this study is to identify determinants of infant mortality in community of Gilgel Gibe Field Research Center, Southwest Ethiopia.

Methods

A community based matched case–control study was conducted. The study covered 133 infants who died during infancy between January 2010 and February 2011 in the study area. For each case, a control with approximately same date of birth and survived his/her first year of live and alive at time data collection was selected. Conditional logistic regression method was used to identify determinant factors of infant mortality using Epi-info 3.5.1 statistical software.

Results

According to the final logistic regression model, not attending antenatal care follow-up [AOR=2.04, 95% CI:(1.04,4.02)], not using soap for hand washing before feeding child [AOR=2.50, 95% CI: (1.32,4.76)], negative perceived benefits of mother to modern treatment and prevention [AOR=2.76, 95% CI: (1.21,6.09)], small birth size [AOR=2.91, 95% CI: (1.01,8.46)] and high birth order with short birth interval [AOR=3.80, 95% CI: (1.20,11.98)] were found to be independent determinants of infant mortality.

Conclusions

Antenatal care follow-up, hand washing habit with soap before feeding child, birth size, perceived benefits of mothers to modern treatment, birth order and preceding birth interval were determinants of infant mortality.
Development, scoring, and reliability of the Microscale Audit of Pedestrian Streetscapes (MAPS)
Authors: Millstein Rachel A , Cain Kelli L , Sallis James F , Conway Terry L , Geremia Carrie , Frank Lawrence D , Chapman Jim , Van Dyck Delfien , Dipzinski Lindsay R , Kerr Jacqueline , Glanz Karen , Saelens Brian E
Published: April 2013

Background

Streetscape (microscale) features of the built environment can influence people’s perceptions of their neighborhoods’ suitability for physical activity. Many microscale audit tools have been developed, but few have published systematic scoring methods. We present the development, scoring, and reliability of the Microscale Audit of Pedestrian Streetscapes (MAPS) tool and its theoretically-based subscales.

Methods

MAPS was based on prior instruments and was developed to assess details of streetscapes considered relevant for physical activity. MAPS sections (route, segments, crossings, and cul-de-sacs) were scored by two independent raters for reliability analyses. There were 290 route pairs, 516 segment pairs, 319 crossing pairs, and 53 cul-de-sac pairs in the reliability sample. Individual inter-rater item reliability analyses were computed using Kappa, intra-class correlation coefficient (ICC), and percent agreement. A conceptual framework for subscale creation was developed using theory, expert consensus, and policy relevance. Items were grouped into subscales, and subscales were analyzed for inter-rater reliability at tiered levels of aggregation.

Results

There were 160 items included in the subscales (out of 201 items total). Of those included in the subscales, 80 items (50.0%) had good/excellent reliability, 41 items (25.6%) had moderate reliability, and 18 items (11.3%) had low reliability, with limited variability in the remaining 21 items (13.1%). Seventeen of the 20 route section subscales, valence (positive/negative) scores, and overall scores (85.0%) demonstrated good/excellent reliability and 3 demonstrated moderate reliability. Of the 16 segment subscales, valence scores, and overall scores, 12 (75.0%) demonstrated good/excellent reliability, three demonstrated moderate reliability, and one demonstrated poor reliability. Of the 8 crossing subscales, valence scores, and overall scores, 6 (75.0%) demonstrated good/excellent reliability, and 2 demonstrated moderate reliability. The cul-de-sac subscale demonstrated good/excellent reliability.

Conclusions

MAPS items and subscales predominantly demonstrated moderate to excellent reliability. The subscales and scoring system represent a theoretically based framework for using these complex microscale data and may be applicable to other similar instruments.
Exposure to public natural space as a protective factor for emotional well-being among young people in Canada
Authors: Huynh Quynh , Craig Wendy , Janssen Ian , Pickett William
Published: April 2013

Background

Positive emotional well-being is fundamentally important to general health status, and is linked to many favorable health outcomes. There is societal interest in understanding determinants of emotional well-being in adolescence, and the natural environment represents one potential determinant. Psychological and experimental research have each shown links between exposure to nature and both stress reduction and attention restoration. Some population studies have suggested positive effects of green space on various indicators of health. However, there are limited large-scale epidemiological studies assessing this relationship, specifically for populations of young people and in the Canadian context. The objective of this study was to examine the relationship between exposure to public natural space and positive emotional well-being among young adolescent Canadians.

Methods

This cross-sectional study was based upon the Canadian 2009/10 Health Behaviour in School-aged Children Survey with linked geographic information system (GIS) data. Following exclusions, the sample included 17 249 (grades 6 to 10, mostly ages 11 to 16) students from 317 schools. Features of the natural environment were extracted using GIS within a 5 km radius circular buffer surrounding each school. Multilevel logistic regression was used to examine the relationship between the presence of public natural space (features include green and blue spaces such as parks, wooded areas, and water bodies) and students’ reports of positive emotional well-being, while controlling for salient covariates and the clustered nature of the data.

Results

Over half of Canadian youth reported positive emotional well-being (58.5% among boys and 51.6% among girls). Relationships between measures of natural space and positive emotional well-being were weak and lacked consistency overall, but modest protective effects were observed in small cities. Positive emotional well-being was more strongly associated with other factors including demographic characteristics, family affluence, and perceptions of neighbourhood surroundings.

Conclusion

Exposure to natural space in youth’s immediate living environment may not be a leading determinant of their emotional well-being. The relationship between natural space and positive emotional well-being may be context specific, and thus different for Canadian youth compared to adult populations and those studied in other nations. Factors of the individual context were stronger potential determinants.
Heart rate variability in sciatica patients referred to spine surgery: a case control study
Authors: Södervall Jarmo , Karppinen Jaro , Puolitaival Jukka , Kyllönen Eero , Kiviniemi Antti M , Tulppo Mikko P , Hautala Arto J
Published: April 2013

Background

A chronic pain condition may result in altered autonomic nervous system regulation in various patient populations. We evaluated whether autonomic regulation differs between sciatica patients referred to spine surgery and age-matched healthy controls analyzed with heart rate variability techniques (HRV).

Methods

HRV of patients (n = 201) and healthy controls (n = 138) were measured in standing conditions (5 min). High frequency (HF) power as an index of cardiac vagal modulation and the low-to-high-frequency (LF/HF) ratio and short-term fractal scaling exponent α1as indices of sympathovagal balance were analyzed. Pain intensity was assessed on a Visual Analog Scale (VAS) and perceived disability with Oswestry Disability Index.

Results

The Oswestry and VAS scores were higher in the patients than in the controls (p < 0.0001 for both). HF power was markedly lower for the patients compared to the controls (p < 0.0001). The LF/HF ratio and α1were higher in the patients than in the controls (p < 0.01 for both). After adjusting for sex, smoking, BMI, and leisure-time physical activity, HF power (p = 0.011) and α1(p = 0.012) still differed between the groups. Among the patients, HF power was slightly associated with the duration of chronic pain (r = −.232, p = 0.003).

Conclusions

Sciatica patients referred to spine surgery had altered cardiac autonomic regulation expressed as decreased vagal activity and an increased sympathovagal balance toward sympathetic dominance when compared with age-matched healthy controls.
Herbal compound “Songyou Yin” attenuates hepatoma cell invasiveness and metastasis through downregulation of cytokines secreted by activated hepatic stellate cells
Authors: Jia Qing-An , Wang Zhi-Ming , Ren Zheng-Gang , Bu Yang , Xie Xiao-Ying , Wang Yan-Hong , Zhang Lan , Zhang Qiang-Bo , Xue Tong-Chun , Deng Li-Fen , Tang Zhao-You
Published: April 2013

Background

Activated hepatic stellate cells (aHSCs) play an important role in the progression of hepatocellular carcinoma (HCC). Here, we determined if cytokines secreted in response to the herbal compound “Songyou Yin” (SYY) treatment of aHSCs could influence invasiveness and metastatic capabilities of hepatoma cells.

Methods

Primary rat hepatic stellate cells (HSCs) were isolated, activated, divided into SYY treated and untreated (nSYY) groups, and conditioned media (CM-SYY and CM-nSYY, respectively) were collected. The hepatoma cell line, McA-RH7777 was cultured for 4 weeks with SYY, CM-SYY, and CM-nSYY, designated McA-SYY, McA-SYYCM and McA-nSYYCM. The invasiveness and metastatic capabilities were evaluated using Matrigel invasion assayin vitroand pulmonary metastasisin vivo. Matrix metalloproteinase-2 (MMP-2), MMP-9, E-cadherin, N-cadherin, and vimentin protein levels in McA-SYYCM and McA-nSYYCM were evaluated by Western blot. Cytokine levels in conditioned media were tested using enzyme-linked immunosorbent assay (ELISA).

Results

Matrigel invasion assay indicated that the number of McA-SYYCM cells passing through the basement membrane was less than in McA-nSYYCM cells (P< 0.01). Similar results were also observedin vivofor lung metastasis. McA-SYYCM cells showed less pulmonary metastasis capabilities than McA-nSYYCM cells (P< 0.001). The reduced expression of MMP-2 and reversed epithelial to mesenchymal transition with E-cadherin upregulation, and N-cadherin and vimentin downregulation were also found in McA-SYYCM compared to McA-nSYYCM. Metastasis-promoting cytokines hepatocyte growth factor, interleukin-6, transforming growth factor-β1, and vascular endothelial growth factor were markedly decreased in CM-SYY compared to CM-nSYY.

Conclusions

SYY attenuates hepatoma cell invasiveness and metastasis capabilities through downregulating cytokines secreted by activated hepatic stellate cells.
In vitro and in vivo antibacterial activities of cranberry press cake extracts alone or in combination with β-lactams against Staphylococcus aureus
Authors: Diarra Moussa S , Block Glenn , Rempel Heidi , Oomah B Dave , Harrison Judy , McCallum Jason , Boulanger Simon , Brouillette Éric , Gattuso Mariza , Malouin François
Published: April 2013

Background

Cranberry fruits possess many biological activities partly due to their various phenolic compounds; however the underlying modes of action are poorly understood. We studied the effect of cranberry fruit extracts on the gene expression of Staphylococcus aureus to identify specific cellular processes involved in the antibacterial action.

Methods

Transcriptional profiles of four S. aureus strains grown in broth supplemented or not with 2 mg/ml of a commercial cranberry preparation (Nutricran®90) were compared using DNA arrays to reveal gene modulations serving as markers for biological activity. Ethanol extracted pressed cakes from fresh fruits also produced various fractions and their effects on marker genes were demonstrated by qPCR. Minimal inhibitory concentrations (MICs) of the most effective cranberry fraction (FC111) were determined against multiple S. aureus strains and drug interactions with β-lactam antibiotics were also evaluated. Incorporation assays with [3H]-radiolabeled precursors were performed to evaluate the effect of FC111 on DNA, RNA, peptidoglycan (PG) and protein biosynthesis.

Results

Treatment of S. aureus with Nutricran®90 or FC111 revealed a transcriptional signature typical of PG-acting antibiotics (up-regulation of genes vraR/S, murZ, lytM, pbp2, sgtB, fmt). The effect of FC111 on PG was confirmed by the marked inhibition of incorporation of D-[3H]alanine. The combination of β-lactams and FC111 in checkerboard assays revealed a synergistic activity against S. aureus including strain MRSA COL, which showed a 512-fold drop of amoxicillin MIC in the presence of FC111 at MIC/8. Finally, a therapeutic proof of concept was established in a mouse mastitis model of infection. S. aureus-infected mammary glands were treated with amoxicillin, FC111 or a combination of both; only the combination significantly reduced bacterial counts from infected glands (P<0.05) compared to the untreated mice.

Conclusions

The cranberry fraction FC111 affects PG synthesis of S. aureus and acts in synergy with β-lactam antibiotics. Such a fraction easily obtained from poorly exploited press-cake residues, may find interesting applications in the agri-food sector and help reduce antibiotic usage in animal food production.
Hellebrin and its aglycone form hellebrigenin display similar in vitro growth inhibitory effects in cancer cells and binding profiles to the alpha subunits of the Na+/K+-ATPase
Authors: Moreno Y Banuls Laetitia , Katz Adriana , Miklos Walter , Cimmino Alessio , Tal Daniel M. , Ainbinder Elena , Zehl Martin , Urban Ernst , Evidente Antonio , Kopp Brigitte , Berger Walter , Feron Olivier , Karlish Steven , Kiss Robert
Published: April 2013

Background

Surface-expressed Na+/K+-ATPase (NaK) has been suggested to function as a non-canonical cardiotonic steroid-binding receptor that activates multiple signaling cascades, especially in cancer cells. By contrast, the current study establishes a clear correlation between the IC50
in vitro growth inhibitory concentration in human cancer cells and the Ki for the inhibition of activity of purified human α1β1 NaK.

Methods

The in vitro growth inhibitory effects of seven cardiac glycosides including five cardenolides (ouabain, digoxin, digitoxin, gitoxin, uzarigenin-rhamnoside, and their respective aglycone forms) and two bufadienolides (gamabufotalin-rhamnoside and hellebrin, and their respective aglycone forms) were determined by means of the MTT colorimetric assay and hellebrigenin-induced cytotoxic effects were visualized by means of quantitative videomicroscopy. The binding affinity of ten of the 14 compounds under study was determined with respect to human α1β1, α2β1 and α3β1 NaK complexes. Lactate releases and oxygen consumption rates were also determined in cancer cells treated with these various cardiac glycosides.

Results

Although cardiotonic steroid aglycones usually display weaker binding affinity and in vitro anticancer activity than the corresponding glycoside, the current study demonstrates that the hellebrin / hellebrigenin pair is at odds with respect to this rule. In addition, while some cardiac steroid glycosides (e.g., digoxin), but not the aglycones, display a higher binding affinity for the α2β1 and α3β1 than for the α1β1 complex, both hellebrin and its aglycone hellebrigenin display ~2-fold higher binding affinity for α1β1 than for the α2β1 and α3β1 complexes. Finally, the current study highlights a common feature for all cardiotonic steroids analyzed here, namely a dramatic reduction in the oxygen consumption rate in cardenolide- and bufadienolide-treated cells, reflecting a direct impact on mitochondrial oxidative phosphorylation.

Conclusions

Altogether, these data show that the binding affinity of the bufadienolides and cardenolides under study is usually higher for the α2β1 and α3β1 than for the α1β1 NaK complex, excepted for hellebrin and its aglycone form, hellebrigenin, with hellebrigenin being as potent as hellebrin in inhibiting in vitro cancer cell growth.
Members of the high mobility group B protein family are dynamically expressed in embryonic neural stem cells
Authors: Abraham Ariel B , Bronstein Robert , Chen Emily I , Koller Antonius , Ronfani Lorenza , Maletic-Savatic Mirjana , Tsirka Stella E
Published: April 2013

Neural Stem Cells (NSCs) are a distinct group of cells present in the embryonic and adult mammalian central nervous system (CNS) that are able to differentiate into neurons, astrocytes and oligodendrocytes. As NSC proliferation declines with age, factors that regulate this process need to be defined. To search for NSC regulatory factors, we performed a quantitative shotgun proteomics study that revealed that members of the High Mobility Group B (HMGB) family are highly expressed in NSCs. Using a neurosphere assay, we report the differential expression of HMGB 1, 2, 3, and 4 mRNAs in proliferating NSCs isolated from various time points during embryonic development, as well as the dynamic expression of HMGB1 and B2 mRNAs and proteins in differentiating embryonic NSCs. Expression of HMGB2 underwent the most dramatic changes during the developmental ages examined; as a result, we assessed its role in NSC proliferation and differentiation. We report the predominance of small diameter HMGB2-/- neurospheres in comparison to wild-type, which correlated with increased proliferation in these smaller HMGB2-/- neurospheres. Our data suggest that HMGB2 plays a regulatory role in NSC cell proliferation and maintenance pathways.
Growth, structure, morphology, and magnetic properties of Ni ferrite films
Authors: Dong Chunhui , Wang Gaoxue , Guo Dangwei , Jiang Changjun , Xue Desheng
Published: April 2013

The morphology, structure, and magnetic properties of nickel ferrite (NiFe2O4) films fabricated by radio frequency magnetron sputtering on Si(111) substrate have been investigated as functions of film thickness. Prepared films that have not undergone post-annealing show the better spinel crystal structure with increasing growth time. Meanwhile, the size of grain also increases, which induces the change of magnetic properties: saturation magnetization increased and coercivity increased at first and then decreased. Note that the sample of 10-nm thickness is the superparamagnetic property. Transmission electron microscopy displays that the film grew with a disorder structure at initial growth, then forms spinel crystal structure as its thickness increases, which is relative to lattice matching between substrate Si and NiFe2O4.
Development of dextran nanoparticles for stabilizing delicate proteins
Authors: Wu Fei , Zhou Zhihua , Su Jing , Wei Liangming , Yuan Weien , Jin Tuo
Published: April 2013

One of the most challenging problems in the development of protein pharmaceuticals is to deal with stabilities of proteins due to its complicated structures. This study aims to develop a novel approach to stabilize and encapsulate proteins into dextran nanoparticles without contacting the interface between the aqueous phase and the organic phase. The bovine serum albumin, granulocyte-macrophage colony-stimulating factor (GM-CSF), granulocyte colony-stimulating factor (G-CSF), β-galactosidase, and myoglobin were selected as model proteins. The proteins were added into an aqueous solution containing the dextran and polyethylene glycol, and then encapsulated into dextran nanoparticles by aqueous-aqueous freezing-induced phase separation. The encapsulation efficiency and recovery of dextran nanoparticles were determined. The dextran nanoparticles loaded with proteins were characterized by scanning electron microscopy and particle size analysis. The protein aggregation was determined by size-exclusion chromatography-high-performance chromatography, and the bioactivity of proteins recovered during formulation steps was determined. The bioactivity of GM-CSF, G-CSF, and β-galactosidase were examined by the proliferation of TF-1 cell, NSF-60 cell, and ortho-nitrophenyl-β-galactoside assay, respectively. The results of bioactivity recovered show that this novel dextran nanoparticle can preserve the protein's bioactivity during the preparation process. LysoSensor™ Yellow/Blue dextran, a pH-sensitive indicator with fluorescence excited at two channels, was encapsulated into dextran nanoparticles to investigate the ability of dextran nanoparticles to resist the acidic microenvironment (pH < 2.5). The result shows that the dextran nanoparticles attenuate the acidic microenvironment in the poly (lactic-co-glycolic acid) microsphere by means of the dilution effect. These novel dextran nanoparticles provided an appealing approach to stabilize the delicate proteins for administration.
Aquareovirus protein VP6 colocalizes with NS80 protein in infected and transfected cells
Authors: Wen Dawei , Yan Liming , Shao Ling , Guo Hong , Li Xiaoming , Fang Qin
Published: April 2013

Background

Aquareovirus particle is comprised of central core and outer capsid, which is built by seven structural proteins (VP1-VP7). The protein VP6 has been identified to be a clamp protein of stabilizing inner core frame VP3, and bridging outer shell protein VP5. However, the biological properties of VP6 in viral life cycle remain unknown.

Results

The recombinant VP6 (rVP6) of aquareovirus was expressed in E. coli, and the polyclonal antibody against VP6 was generated by using purified rVP6 in this study. Following the preparation of VP6 antibody, the VP6 component in aquareovirus infected cells and purified viral particles was detected by Immunoblotting (IB) assay. Furthermore, using Immunofluorescence (IF) microscopy, singly transfected VP6 protein was observed to exhibit a diffuse distribution mainly in the cytoplasm, while it appeared inclusion phenotype in infected cells. Meanwhile, inclusion structures were also identified when VP6 was coexpressed with nonstructural protein NS80 in cotransfected cells.

Conclusions

VP6 can be recruited by NS80 to its inclusions in both infected and transfected cells. The colocalization of VP6 and NS80 is corresponding to their homologous proteins σ2 and μNS in MRV. Our results suggest that VP6 may play a significant role in viral replication and particle assembly.
Effects of continuous renal replacement therapy on renal inflammatory cytokines during extracorporeal membrane oxygenation in a porcine model
Authors: Yimin Hu , Wenkui Yu , Jialiang Shi , Qiyi Chen , Juanhong Shen , Zhiliang Lin , Changsheng He , Ning Li , Jieshou Li
Published: April 2013

Background

Extracorporeal membrane oxygenation (ECMO) has been recommended for the treatment of patients with acute, potentially reversible, life-threatening respiratory failure which unresponsive to conventional therapy. But it is unclear about how ECMO affects renal tissue.

Methods

Twenty-four piglets weighing 25 to 32 kg were used in this experiment. The piglets were randomly allocated to 4 groups of 6 animals each: sham group (S group), control group (C group), VV-ECMO group (E group), VV-ECMO combined with CRRT group (EC group). The piglets were sacrificed and the kidney tissue were harvest to determine the levels of IL-1β, IL-6, TNF-α and NF-КB by using the ELISA and RT-PCR method, respectively.

Results

Compared with C group and S group, E group renal tissue IL-1β, IL-6, TNF-α and NF-КB expression increased significantly, respectively (p < 0.01). Compared with E group, EC group showed renal tissue IL-1β, IL-6, TNF-α and NF-КB expression decreased significantly, respectively (p < 0.05).

Conclusion

ECMO enables to inflammatory cytokines including IL-1β, IL-6, TNFα, NF-КB released significantly, renal function impaired and immune homeostasis were to imbalance; ECMO combined with CRRT treatment can alleviate levels of inflammatory cytokines, maintain immune homeostasis balance and thus ameliorate the ECMO-related acute kidney injury(AKI).
Enhancement of fermentable sugar yields by α-xylosidase supplementation of commercial cellulases
Authors: Jabbour Dina , Borrusch Melissa S , Banerjee Goutami , Walton Jonathan D
Published: April 2013

Background

Although α-linked xylose is a major constituent of the hemicelluloses of land plants, few secreted α-xylosidases have been described from fungi or bacteria. AxlA of Aspergillus niger is a secreted α-xylosidase that was earlier shown to promote the release of free glucose (Glc) and xylose (Xyl) from substrates containing α-linked xylose, including isoprimeverose (IP), the heptasaccharide subunit of pea xyloglucan (XG), and tamarind XG.

Results

The utility of AxlA for enhancing release of free Glc and Xyl in combination with commercial enzyme cocktails from dicotyledonous and monocotyledonous plants was examined. Without AxlA supplementation, a mixture of CTec2 and HTec2 (both of which are derived from T. reesei) did not release significant levels of Glc from pea XG or tamarind XG. This is consistent with their lack of detectable α-xylosidase activity using model substrates. On alkaline hydrogen peroxide-pretreated corn stover, supplementation of CTec2/HTec2 (at a loading of 2.5 mg/g glucan) with AxlA (at a loading of 8 mg/g glucan) increased Glc yields from 82% to 88% of the total available Glc and increased Xyl yields from 55% to 60%. AxlA supplementation also improved Glc yields from corn stover treated with the commercial cellulase Accellerase 1000. The AxlA enhancement was not a general protein effect because bovine serum albumin or bovine gamma-globulin at similar concentrations did not enhance Glc yields from corn stover in response to CTec2/HTec2. Supplementation of CTec2/HTec2 with AxlA did not enhance Glc release from pretreated green or etiolated pea tissue. However, AxlA did enhance Glc and Xyl yields compared to CTec2/HTec2 alone from another dicotyledonous herbaceous plant, Chenopodium album (lamb’s quarters).

Conclusion

Supplementation of commercial cellulase cocktails with AxlA enhances yields of Glc and Xyl from some biomass substrates under some conditions, and may prove useful in industrial lignocellulose conversion.
Paediatric Visceral Leishmaniasis in Italy: a ‘One Health’ approach is needed
Authors: Lorusso Vincenzo , Dantas-Torres Filipe , Caprio Francesco , Manzionna Mariano , Santoro Nicola , Baneth Gad , Otranto Domenico
Published: April 2013

Here we describe a case of paediatric visceral leishmaniasis recorded in an infant initially suspected for acute lymphoblastic leukaemia due to the clinical and haematological presentation. Eventually the patient was found positive for Leishmania infantum infection and successfully treated. This case emphasises how pivotal a ‘One Health’ approach is for diagnosing this zoonotic disease; highlighting the importance of including Visceral Leishmaniasis in the differential diagnosis of leukaemia-like syndromes in infants travelling to, and living in, the Mediterranean region.
Development and characterization of a high-throughput in vitro cord formation model insensitive to VEGF inhibition
Authors: Falcon Beverly L , O’Clair Belinda , McClure Don , Evans Glenn F , Stewart Julie , Swearingen Michelle L , Chen Yuefeng , Allard Kevin , Lee Linda N , Neote Kuldeep , McEwen Dyke P , Uhlik Mark T , Chintharlapalli Sudhakar
Published: April 2013

Background

Anti-VEGF therapy reduces tumor blood vessels, however, some vessels always remain. These VEGF insensitive vessels may help support continued tumor growth and metastases. Manyin vitroassays examining multiple steps of the angiogenic process have been described, but the majority of these assays are sensitive to VEGF inhibition. There has been little focus on the development of high-throughput,in vitroassays to model the vessels that are insensitive to VEGF inhibition.

Methods

Here, we describe a fixed end-point and kinetic, high-throughput stem cell co-culture model of cord formation.

Results

In this system, cords develop within 24 hours, at which point they begin to lose sensitivity to VEGF inhibitors, bevacizumab, and ramucirumab. Consistent with the hypothesis that other angiogenic factors maintain VEGF-independent vessels, pharmacologic intervention with a broad spectrum anti-angiogenic antagonist (suramin), a vascular disrupting agent (combretastatin), or a combination of VEGF and Notch pathway inhibitors reduced the established networks. In addition, we used ourin vitroapproach to develop anin vivoco-implant vasculogenesis model that connects with the endogenous vasculature to form functional blood vessels. Similar to thein vitrosystem, over time these vessels become insensitive to VEGF inhibition.

Conclusion

Together, these models may be used to identify novel drugs targeting tumor vessels that are not sensitive to VEGF inhibition.
Publication bias in animal research: a systematic review protocol
Authors: Briel Matthias , Müller Katharina F , Meerpohl Joerg J , von Elm Erik , Lang Britta , Motschall Edith , Gloy Viktoria , Lamontagne Francois , Schwarzer Guido , Bassler Dirk
Published: April 2013

Background

Systematic reviews and meta-analyses of pre-clinical studies, in vivo animal experiments in particular, can influence clinical care. Publication bias is one of the major threats of validity in systematic reviews and meta-analyses. Previous empirical studies suggested that systematic reviews and meta-analyses have become more prevalent until 2010 and found evidence for compromised methodological rigor with a trend towards improvement. We aim to comprehensively summarize and update the evidence base on systematic reviews and meta-analyses of animal studies, their methodological quality and assessment of publication bias in particular.

Methods/Design

The objectives of this systematic review are as follows:

To investigate the epidemiology of published systematic reviews of animal studies until present.

To examine methodological features of systematic reviews and meta-analyses of animal studies with special attention to the assessment of publication bias.

To investigate the influence of systematic reviews of animal studies on clinical research by examining citations of the systematic reviews by clinical studies.

Eligible studies for this systematic review constitute systematic reviews and meta-analyses that summarize in vivo animal experiments with the purpose of reviewing animal evidence to inform human health. We will exclude genome-wide association studies and animal experiments with the main purpose to learn more about fundamental biology, physical functioning or behavior.

In addition to the inclusion of systematic reviews and meta-analyses identified by other empirical studies, we will systematically search Ovid Medline, Embase, ToxNet, and ScienceDirect from 2009 to January 2013 for further eligible studies without language restrictions.

Two reviewers working independently will assess titles, abstracts, and full texts for eligibility and extract relevant data from included studies. Data reporting will involve a descriptive summary of meta-analyses and systematic reviews.

Discussion

Results are expected to be publicly available later in 2013 and may form the basis for recommendations to improve the quality of systematic reviews and meta-analyses of animal studies and their use with respect to clinical care.