1,909 research outputs found

    Dynamic cofilin phosphorylation in the control of lamellipodial actin homeostasis

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    During animal cell chemotaxis, signalling at the plasma membrane induces actin polymerisation to drive forward cell movement. Since the cellular pool of actin is limited, efficient protrusion formation also requires the coordinated disassembly of pre-existing actin filaments. To search for proteins that can monitor filamentous and globular actin levels to maintain the balance of polymerisation and disassembly, we followed changes in the proteome induced by RNA interference (RNAi)mediated alterations in actin signalling. This unbiased approach revealed an increase in the levels of an inactive, phosphorylated form of the actin-severing protein cofilin in cells unable to generate actin-based lamellipodia. Conversely, an increase in F-actin levels induced the dephosphorylation and activation of cofilin via activation of the Ssh phosphatase. Similarly, in the context of acute phosphoinositide 3-kinase (PI3K) signalling, dynamic changes in cofilin phosphorylation were found to depend on the Ssh phosphatase and on changes in lamellipodial Factin. These results indicate that changes in the extent of cofilin phosphorylation are regulated by Ssh in response to changes in the levels and/or organisation of F-actin. Together with the recent finding that Ssh phosphatase activity is augmented by F-actin binding, these results identify Ssh-dependent regulation of phosphorylated cofilin levels as an important feedback control mechanism that maintains actin filament homeostasis during actin signalling

    Investigation of the human nasal microbiome in persons with long- And short-term exposure to methicillin-resistant <i>Staphylococcus aureus</i> and other bacteria from the pig farm environment

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    Since its emergence in the early 2000s, livestock-associated methicillin-resistant Staphylococcus aureus clonal complex 398 (LA-MRSA CC398) has led to an increasing number of human infections in Denmark and other European countries with industrial pig production. LA-MRSA CC398 is primarily associated with skin infections among pig farm workers but is also increasingly recognized as a cause of life-threatening disease among elderly and immunocompromised people. Pig farm workers may serve as vehicles for the spread of LA-MRSA CC398 and other farm-origin bacteria between farms and into the general population. Yet, little is known about the bacterial community dynamics in pig farm workers and other persons with long- and short-term exposure to the pig farm environment. To gain insight into this, we investigated the nasal microbiomes in pig farm workers during a workweek on four LA-MRSA CC398-positive pig farms, as well as in short-term visitors two hours before, immediately after, and 48 hours after a 1-hour visit to another LA-MRSA CC398-positive pig farm. S. aureus and LA-MRSA CC398 carriage was quantified by means of culture, and the composition of the bacterial communities was investigated through sequencing of the 16S rRNA gene. Pig farm workers often carried LA-MRSA CC398 and other bacteria from the pig farm environment, both at work and at home, although at lower levels at home. In contrast, short-term visitors were subject to a less dramatic and rapidly reversible change in the nasal bacterial community composition. These results suggest that pig farm workers may be an important source of LA-MRSA CC398 and perhaps other pathogens of human and veterinary relevance

    Open Food Network: the Role of ICT to Support Regional Food Supply Chains in Australia

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    Many organizations have introduced various ICT-enabled innovations to improve economic, environmental and social performance. The Open Food Network (OFN) is an example of an ICT enabled innovation that has the potential to enhance the sustainability of regional food supply chain by improving farmers’ access to local and regional markets and consumers’ access to fresh local produce, as well as optimizing the regional food distribution and improving local community welfare. OFN has just been recently launched in Australia and currently there is a limited understanding of the actual impacts. This research-in-progress paper aims to evaluate the effectiveness of the OFN system in connecting and supporting the sustainability of regional food supply chain communities in Australia that will help devise strategies for expanding the use beyond Australia. The findings contribute to a longer term research program that investigates how ICT can support sustainability initiatives within organizations and supply chains

    Clonal occurrence of <i>Salmonella</i> Weltevreden in cultured shrimp in the Mekong Delta, Vietnam

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    This study investigated the occurrence, serovar and antimicrobial resistance of Salmonella spp. in shrimp samples from intensive and extensive farms located in three different provinces in the Mekong Delta, Vietnam. Shrimp from 11 of the 48 farms all contained S. Weltevreden, except for one farm yielding S. Agona, with no difference in Salmonella occurrence between the two production systems. Pulsed field gel electrophoresis (PFGE) of S. Weltevreden showed closely related XbaI pulse types, suggesting a clonal relationship despite the farms and shrimp samples being epidemiologically unrelated. S. Weltevreden was susceptible to most antimicrobials tested, with a few strains being resistant to florfenicol, chloramphenicol, sulfamethoxazole or trimethoprim. Future studies of the ecology of S. Weltevreden should establish if this serovar may survive better and even multiply in warm-water shrimp farm environments compared to other Salmonella serovars

    Identification and Antimicrobial Resistance of Bacteria Isolated from Probiotic Products Used in Shrimp Culture

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    Probiotics are increasingly used in aquaculture to control diseases and improve feed digestion and pond water quality; however, little is known about the antimicrobial resistance properties of such probiotic bacteria and to what extent they may contribute to the development of bacterial resistance in aquaculture ponds. Concerns have been raised that the declared information on probiotic product labels are incorrect and information on bacterial composition are often missing. We therefore evaluated seven probiotics commonly used in Vietnamese shrimp culture for their bacterial species content, phenotypic antimicrobial resistance and associated transferable resistance genes. The bacterial species was established by 16S rRNA sequence analysis of 125 representative bacterial isolates. MIC testing was done for a range of antimicrobials and whole genome sequencing of six multiple antimicrobial resistant Bacillus spp. used to identify resistance genes and genetic elements associated with horizontal gene transfer. Thirteen bacterial species declared on the probiotic products could not be identified and 11 non-declared Bacillus spp. were identified. Although our culture-based isolation and identification may have missed a few bacterial species present in the tested products this would represent minor bias, but future studies may apply culture independent identification methods like pyro sequencing. Only 6/60 isolates were resistant to more than four antimicrobials and whole genome sequencing showed that they contained macrolide (ermD), tetracycline (tetL), phenicol (fexA) and trimethoprim (dfrD, dfrG and dfrK) resistance genes, but not known structures associated with horizontal gene transfer. Probiotic bacterial strains used in Vietnamese shrimp culture seem to contribute with very limited types and numbers of resistance genes compared to the naturally occurring bacterial species in aquaculture environments. Approval procedures of probiotic products must be strengthened through scientific-based efficacy trials and product labels should allow identification of individual bacterial strains and inform the farmer on specific purpose, dosage and correct application measures

    The beta-Oslo method: experimentally constrained (n,Îłn,\gamma) reaction rates relevant to the rr-process

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    Unknown neutron-capture reaction rates remain a significant source of uncertainty in state-of-the-art rr-process nucleosynthesis reaction network calculations. As the rr-process involves highly neutron-rich nuclei for which direct (n,Îłn,\gamma) cross-section measurements are virtually impossible, indirect methods are called for to constrain (n,Îłn,\gamma) cross sections used as input for the rr-process nuclear network. Here we discuss the newly developed beta-Oslo method, which is capable of providing experimental input for calculating (n,Îłn,\gamma) rates of neutron-rich nuclei. The beta-Oslo method represents a first step towards constraining neutron-capture rates of importance to the rr-process.Comment: 4 pages, 1 figure, conference proceedings Nuclei in the Cosmos XV 2018, Italy

    Congenital syphilis, still a reality in 21st century: a case report

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    Congenital syphilis is a preventable disease and its presence reflects a failure of prenatal care delivery systems, as well as syphilis control programmes. The procedure to prevent congenital syphilis through antenatal screening and treatment is well established. But implementation of effective programmes has proved very difficult especially in resource constrained countries
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