Toxoplasma Effector MAF1 Mediates Recruitment of Host Mitochondria and Impacts the Host Response

Recent information has revealed the functional diversity and importance of mitochondria in many cellular processes including orchestrating the innate immune response. Intriguingly, several infectious agents, such as Toxoplasma, Legionella, and Chlamydia, have been reported to grow within vacuoles surrounded by host mitochondria. Although many hypotheses have been proposed for the existence of host mitochondrial association (HMA), the causes and biological consequences of HMA have remained unanswered. Here we show that HMA is present in type I and III strains of Toxoplasma but missing in type II strains, both in vitro and in vivo. Analysis of F1 progeny from a type II×III cross revealed that HMA is a Mendelian trait that we could map. We use bioinformatics to select potential candidates and experimentally identify the polymorphic parasite protein involved, mitochondrial association factor 1 (MAF1). We show that introducing the type I (HMA+) MAF1 allele into type II (HMA-) parasites results in conversion to HMA+ and deletion of MAF1 in type I parasites results in a loss of HMA. We observe that the loss and gain of HMA are associated with alterations in the transcription of host cell immune genes and the in vivo cytokine response during murine infection. Lastly, we use exogenous expression of MAF1 to show that it binds host mitochondria and thus MAF1 is the parasite protein directly responsible for HMA. Our findings suggest that association with host mitochondria may represent a novel means by which Toxoplasma tachyzoites manipulate the host. The existence of naturally occurring HMA+ and HMA- strains of Toxoplasma, Legionella, and Chlamydia indicates the existence of evolutionary niches where HMA is either advantageous or disadvantageous, likely reflecting tradeoffs in metabolism, immune regulation, and other functions of mitochondria. © 2014 Pernas et al

Norovirus Regulation of the Innate Immune Response and Apoptosis Occurs via the Product of the Alternative Open Reading Frame 4

Small RNA viruses have evolved many mechanisms to increase the capacity of their short genomes. Here we describe the identification and characterization of a novel open reading frame (ORF4) encoded by the murine norovirus (MNV) subgenomic RNA, in an alternative reading frame overlapping the VP1 coding region. ORF4 is translated during virus infection and the resultant protein localizes predominantly to the mitochondria. Using reverse genetics we demonstrated that expression of ORF4 is not required for virus replication in tissue culture but its loss results in a fitness cost since viruses lacking the ability to express ORF4 restore expression upon repeated passage in tissue culture. Functional analysis indicated that the protein produced from ORF4 antagonizes the innate immune response to infection by delaying the upregulation of a number of cellular genes activated by the innate pathway, including IFN-Beta. Apoptosis in the RAW264.7 macrophage cell line was also increased during virus infection in the absence of ORF4 expression. In vivo analysis of the WT and mutant virus lacking the ability to express ORF4 demonstrated an important role for ORF4 expression in infection and virulence. STAT1-/- mice infected with a virus lacking the ability to express ORF4 showed a delay in the onset of clinical signs when compared to mice infected with WT virus. Quantitative PCR and histopathological analysis of samples from these infected mice demonstrated that infection with a virus not expressing ORF4 results in a delayed infection in this system. In light of these findings we propose the name virulence factor 1, VF1 for this protein. The identification of VF1 represents the first characterization of an alternative open reading frame protein for the calicivirus family. The immune regulatory function of the MNV VF1 protein provide important perspectives for future research into norovirus biology and pathogenesis

Approaches in biotechnological applications of natural polymers

Natural polymers, such as gums and mucilage, are biocompatible, cheap, easily available and non-toxic materials of native origin. These polymers are increasingly preferred over synthetic materials for industrial applications due to their intrinsic properties, as well as they are considered alternative sources of raw materials since they present characteristics of sustainability, biodegradability and biosafety. As definition, gums and mucilages are polysaccharides or complex carbohydrates consisting of one or more monosaccharides or their derivatives linked in bewildering variety of linkages and structures. Natural gums are considered polysaccharides naturally occurring in varieties of plant seeds and exudates, tree or shrub exudates, seaweed extracts, fungi, bacteria, and animal sources. Water-soluble gums, also known as hydrocolloids, are considered exudates and are pathological products; therefore, they do not form a part of cell wall. On the other hand, mucilages are part of cell and physiological products. It is important to highlight that gums represent the largest amounts of polymer materials derived from plants. Gums have enormously large and broad applications in both food and non-food industries, being commonly used as thickening, binding, emulsifying, suspending, stabilizing agents and matrices for drug release in pharmaceutical and cosmetic industries. In the food industry, their gelling properties and the ability to mold edible films and coatings are extensively studied. The use of gums depends on the intrinsic properties that they provide, often at costs below those of synthetic polymers. For upgrading the value of gums, they are being processed into various forms, including the most recent nanomaterials, for various biotechnological applications. Thus, the main natural polymers including galactomannans, cellulose, chitin, agar, carrageenan, alginate, cashew gum, pectin and starch, in addition to the current researches about them are reviewed in this article.. }To the Conselho Nacional de Desenvolvimento Cientfíico e Tecnológico (CNPq) for fellowships (LCBBC and MGCC) and the Coordenação de Aperfeiçoamento de Pessoal de Nvíel Superior (CAPES) (PBSA). This study was supported by the Portuguese Foundation for Science and Technology (FCT) under the scope of the strategic funding of UID/BIO/04469/2013 unit, the Project RECI/BBB-EBI/0179/2012 (FCOMP-01-0124-FEDER-027462) and COMPETE 2020 (POCI-01-0145-FEDER-006684) (JAT)

Brief Report - Correlation of Helicobacter pylori and Gastric Carcinoma

BACKGROUND: Difference of opinion about the prevalence of H. pylori association with gastric cancer exists in the literature. AIMS: To study the correlation of Helicobacter pylori (H. pylori) to gastric carcinoma. METHODS: 50 proved cases of gastric cancer were studied by Rapid Urease Test, Culture, Histopathology and ELISA test for H. pylori IgG. RESULTS: 68% of cases of gastric cancer were found to be positive for H. pylori infection as compared to 74% of healthy controls. CONCLUSIONS: The prevalence rate of H. pylori infection in our patients of gastric cancer was lower than in the control population though statistically not significant, suggesting that H. pylori may not be responsible for gastric carcinogenesis in this population

Prescribing knowledge in the light of undergraduate clinical pharmacology and therapeutics teaching in India: views of first-year postgraduate students

Prerna Upadhyaya,1 Vikas Seth,2 Monika Sharma,1 Mushtaq Ahmed,1 Vijay Vasant Moghe,1 Zafar Yab Khan,1 Vinay Kumar Gupta,1 Shipra Vikram Jain,1 Utkarsh Soni,1 Manohar Bhatia,1 Kumar Abhijit,1 Jaswant Goyal11Department of Pharmacology, Mahatma Gandhi Medical College, Jaipur, 2Department of Pharmacology, Hind Institute of Medical Sciences, Lucknow, IndiaObjectives: The study aimed to review the prescribing knowledge of first-year postgraduate doctors in a medical college in India, using the principles of good prescribing, to suggest strategies to improve rational prescribing, and to recommend what curriculum planners can do to accomplish this objective.Methods: Fifty first-year postgraduate doctors were asked to fill in a structured questionnaire that sought information regarding their undergraduate training in clinical pharmacology and therapeutics, prescribing habits, and commonly consulted drug information sources. Also, the questionnaire assessed any perceived deficiencies in their undergraduate clinical pharmacology teaching and sought feedback regarding improvement in the teaching.Results: Eighty-eight percent of residents said that they were taught prescription writing in undergraduate pharmacology teaching; 48% of residents rated their prescribing knowledge at graduation as average, 28% good, 4% excellent, 14% poor, and 4% very poor; 58% felt that their undergraduate training did not prepare them to prescribe safely, and 62% felt that their training did not prepare them to prescribe rationally. Fifty-eight percent of residents felt that they had some specific problems with writing a prescription during their internship training, while 92% thought that undergraduate teaching should be improved. Their suggestions for improving teaching methods were recorded.Conclusions: This study concludes that efforts are needed to develop a curriculum that encompasses important aspects of clinical pharmacology and therapeutics along with incorporation of the useful suggestions given by the residents.Keywords: clinical pharmacology and therapeutics, medical education, prescription writing, undergraduate medical curriculum, pharmacovigilance, pharmacoeconomic