Molecular interactions between Mycoplasma hyopneumoniae and host cells

University of Technology Sydney. Faculty of Science.The Mycoplasmas are a group of wall-less bacteria belonging to the Mollicutes that are believed to have diverged from the Gram-positive Firmicutes. Mollicutes have undergone reductive evolution, losing genes for the biosynthesis of essential biomolecules, subsequently having to form parasite relationships with their hosts in order to acquire these nutrients. They form these relationships as both commensals and pathogens, and a number of Mycoplasma species cause significant clinical and agricultural diseases. Mycoplasma hyopneumoniae is the causative agent of porcine enzootic pneumonia, a chronic respiratory disease that affects swine populations worldwide. M. hyopneumoniae colonises the upper respiratory tract by adhering to the rapidly beating cilia where it causes ciliostasis and eventual cilial death [1]. M. hyopneumoniae possesses a family of surface adhesins referred to as the P97 and P102 paralog family that it utilises to adhere to the cilia [2-10]. A hallmark of M. hyopneumoniae infection is a potent inflammatory response which is believed to be one of the contributing factors to the gross lung lesions observed in infected swine [11-13]. M. hyopneumoniae is described as a strict extracellular pathogen that only adheres to cilia and knowledge is lacking on additional receptors that M. hyopneumoniae binds to. Recent studies have however, shown that viable M. hyopneumoniae cells can be cultured from the liver, spleen, kidneys and lymph nodes of infected swine [14-16]. These observations suggest that M. hyopneumoniae has the capability to invade through the epithelial barrier and disseminate to distal tissue sites. In addition to this, large microcolonies have been observed in the respiratory tract of swine infected with M. hyopneumoniae [17]. These microcolonies are reminiscent of biofilms, and although biofilm formation has never been investigated in M. hyopneumoniae it is likely that they play a role in the chronicity of disease. Notably, even when lung lesions in M. hyopneumoniae-infected swine are cleared, bronchial swabs can still test positive for M. hyopneumoniae up to 185 days post-infection (P.I.) [18] and pigs can act as convalescent carriers for up to 200 days P.I. [19]. This suggests that M. hyopneumoniae possesses mechanisms in which it can remain dormant within its host whilst remaining infectious. Vaccines against M. hyopneumoniae can successfully reduce lung lesions but they are unable to prevent transmission in swine herds [20]. In order to create vaccines that inhibit the transmission of M. hyopneumoniae, a better understanding of the disease process is required. This PhD project has thus been devised in order to address the problems outlined above. This work has investigated the ability of adhesins to undergo extensive endoproteolytic processing; demonstrating that proteolytic processing in the P97 and P102 adhesins occurs much more extensively than what has previously been shown. I also show that these adhesins can bind to a myriad of host components such as heparin, fibronectin (Fn) and plasminogen (Plg) and investigate the domains responsible. Additionally, this work presents a number of novel receptors that M. hyopneumoniae targets within its host as well as a comprehensive list of putative adhesins that it utilises to do so. This work has also investigated the ability of M. hyopneumoniae to form biofilms on abiotic surfaces, host cells and within the swine respiratory tract and further demonstrate that surface adhesins play a role in biofilm formation. A number of putative biofilm-associated genes have been identified by screening a transposon mutant library, these genes being potential vaccine candidates. Finally, this work has investigated the ability of M. hyopneumoniae to become internalised by host cells and reside within the cytoplasm. M. hyopneumoniae becomes internalised by vacuole-like structures, and that internalised cells appear to escape from lysosomes to reside free within the cytoplasm. Overall, this PhD project has contributed significantly to understanding how M. hyopneumoniae causes disease. Future work on the novel mechanisms described in this thesis will aid in future vaccine development programs and potentially aid in the control of this important veterinary disease

An Innovative Approach to Impacting Student Academic Achievement and Attitudes: Pilot Study of the HEADS UP Virtual Molecular Biology Lab

Introduction: The Virtual Molecular Biology Lab is an innovative, computer-based educational program designed to teach advanced high school biology students how to create a transgenic mouse model in a simulated laboratory setting. It was created in an effort to combat the current decrease in adolescent enthusiasm for and academic achievement in science and science careers, especially in Hispanic students. Because studies have found that hands-on learning, particularly computer-based instruction, is effective in enhancing science achievement, the Virtual Lab is a potential tool for increasing the number of Hispanic students that choose to enter science fields. [See PDF for complete abstract

MHJ-0461 is a multifunctional leucine aminopeptidase on the surface of Mycoplasma hyopneumoniae

© 2015 The Authors. Published. Aminopeptidases are part of the arsenal of virulence factors produced by bacterial pathogens that inactivate host immune peptides. Mycoplasma hyopneumoniae is a genome-reduced pathogen of swine that lacks the genetic repertoire to synthesize amino acids and relies on the host for availability of amino acids for growth. M. hyopneumoniae recruits plasmin(ogen) onto its cell surface via the P97 and P102 adhesins and the glutamyl aminopeptidase MHJ-0125. Plasmin plays an important role in regulating the inflammatory response in the lungs of pigs infected with M. hyopneumoniae. We show that recombinant MHJ-0461 (rMHJ-0461) functions as a leucine aminopeptidase (LAP) with broad substrate specificity for leucine, alanine, phenylalanine, methionine and arginine and that MHJ-0461 resides on the surface of M. hyopneumoniae. rMHJ-0461 also binds heparin, plasminogen and foreign DNA. Plasminogen bound to rMHJ-0461 was readily converted to plasmin in the presence of tPA. Computational modelling identified putative DNA and heparin-binding motifs on solvent-exposed sites around a large pore on the LAP hexamer. We conclude that MHJ-0461 is a LAP that moonlights as a multifunctional adhesin on the cell surface of M. hyopneumoniae

News-Specific Price Discovery in Credit Default Swap Markets

We examine the lead and lag relation between equity and credit default swap (CDS) markets. We find that price discovery in equity markets only leads CDS markets following aggregate positive news and not so following other news. While difficult to reconcile with standard asset pricing theories, asymmetric price adjustment is common in goods markets, arising from intermediary power. We provide an explanation for this asymmetry based on dealers exploiting informational advantages vis-à-vis investors with hedging motives. Consistent with this explanation, we find that the patterns we document are related to firm-level proxies for hedging demand, as well as economy-wide measures of information asymmetries

Post-translational processing targets functionally diverse proteins in Mycoplasma hyopneumoniae

© 2016 The Authors. Mycoplasma hyopneumoniae is a genome-reduced, cell wall-less, bacterial pathogen with a predicted coding capacity of less than 700 proteins and is one of the smallest self-replicating pathogens. The cell surface of M. hyopneumoniae is extensively modified by processing events that target the P97 and P102 adhesin families. Here, we present analyses of the proteome of M. hyopneumoniae-type strain J using protein-centric approaches (one- and two-dimensional GeLC-MS/MS) that enabled us to focus on global processing events in this species. While these approaches only identified 52% of the predicted proteome (347 proteins), our analyses identified 35 surface-associated proteins with widely divergent functions that were targets of unusual endopro-teolytic processing events, including cell adhesins, lipoproteins and proteins with canonical functions in the cytosol that moonlight on the cell surface. Affinity chromatography assays that separately used heparin, fibronectin, actin and host epithelial cell surface proteins as bait recovered cleavage products derived from these processed proteins, suggesting these fragments interact directly with the bait proteins and display previously unrecognized adhesive functions. We hypothesize that protein processing is underestimated as a post-translational modification in genome-reduced bacteria and prokaryotes more broadly, and represents an important mechanism for creating cell surface protein diversity

Intermitent presumptive treatment of malaria to prevent low birth weight in newborns in a cohort of pregnant women from a malaria endemic area

Objective: To determine and describe the patterns of low birth weight in newborns of a cohort of mothers given intermittent presumptive treatment (IPT) for malaria prevention in a malaria endemic area of Kenya.Design: A longitudinal prospective cohort study.Setting: Got Agulu Health Centre in Usigu Division, Bondo District, Nyanza Province.Subjects: Pregnant women of all parities attending antenatal care services. Only women who gave informed consent for themselves and their newborns after birth were eligible to participate in the study.Results: Parity was highly predictive of birth weight in the study subjects. Primigravidae and secondigravidae had a significantly lower mean birth weight (2952g) than women of higher gravidity (3214g) p-valu

Design and Analysis of Butterfly Valve Disc Using Aluminium (1100) and Al-CNT4% Composite Material

Aluminium (1100) is an extensively used material in the application of water line and drainage applications. If the aluminium (1100) surface contacts the water, an oxide layer will be formed and it prevents the corrosion of aluminium (1100) when compared to other metal and also ithas less weight. But due to their low melting point and low hardness that will wear and deformed easily and cannot be used for high pressure applications. The metal aluminum (1100) will not meet all the required properties suitable for various engineering applications. The present study uses aluminium alloy or aluminium composite material which has the  higher melting point and hardness compare to aluminium (1100). In the present study butterfly valve which is commonly used for water line  application was designed by using Pro-E software and analyzed its  deflection using Ansys software. For the analysis, two  materials such asaluminium (1100) and aluminium carbon nanotube 4% was used and compared these two materials deflections, improvements in behaviors are noted. The results of the study indicates that deflection of Al-CNT4% composite is around 7 times lesser than aluminium (1100). Al-CNT4% is more stable than the aluminium (1100) for the application of butterfly valve disc

PENGARUH KINERJA GUEST SERVICE CENTRE DALAM PELAYANAN ROOM SERVICE SEBUAH HOTEL TERHADAP KEPUASAN KONSUMEN (STUDI KASUS HOTEL NOVOTEL JAKARTA GAJAH MADA PERIODE FEBRUARI - APRIL 2013)

PENGARUH KINERJA GUEST SERVICE CENTRE DALAM PELAYANAN ROOM SERVICE SEBUAH HOTEL TERHADAP KEPUASAN KONSUMEN (STUDI KASUS HOTEL NOVOTEL JAKARTA GAJAH MADA PERIODE FEBRUARI - APRIL 2013)

The Relationship between Decision-Making and Accountability: A Case Study of Two State Community College Systems

Inherent to college governance in many community colleges throughout the nation is the expectation that a collegial or participatory model of decision-making is the appropriate mode of governance. This type of model structures an organization to allow the opportunity for all constituencies to participate in decision-making. Some states, such as California, have mandated a participatory decision-making process, commonly referred to as “shared governance” (AB1725) while others operate in a similar manner but not by legislative mandate. Regardless of the model of decision-making used to govern community colleges, most states are being asked to address educational accountability with regard to student performance outcomes. States, such as Florida, have reorganized their entire educational governance structure (SB1162) in an attempt to increase student success. This case study provides an in-depth look at how internal structures of participatory decision-making respond to external requirements for accountability. The underlying premise for this study is that the decision-making process employed by a community college system at the state and local level significantly impacts any attempt to achieve accountability. The study examined two community college systems at the system (state) and college (local) level: California and Florida. Four research questions guided data collection with an additional sub-research question regarding how perceptions differed at the system and college level. A total of 29 respondents, at both the system and college levels, participated revealing meaningful insights about shared decision-making, accountability, student performance outcomes, performance-based funding and leadership. The findings of this study revealed that 1) whether mandated or not, participatory decision making results in a higher degree of commitment by all constituencies, 2) commitment while not guaranteeing success increases the likelihood of an initiative such as performance based funding improving student performance, 3) an emphasis on accountability shifts the focus to student success and removes barriers to completion, 4) community colleges continue to be under-funded while expected to provide services to meet growth and diversity demands and, 5) leadership is key to the success of any participatory decision-making initiative. This study suggests that additional research is needed to investigate implications of leadership and external influences