344 research outputs found
Influence of the twospotted spider mite, Tetranychus urticae, on the gas exchange of Pinot noir grapevine leaves
The effect of feeding damage by the twospotted spider mite (Tetranychus urticae KOCH; Acari: Tetranychidae) on the gas exchange of grapevine leaves (Vitis vinifera L.; cv. Pinot noir) was investigated. In addition, the influence of some pesticides was studied. A significant reduction of the net CO2 assimilation, transpiration as well as stomatal and mesophyll conductance with increasing mite feeding damage were observed. At 6000 mite-days per leaf the 3rd and 9th main leaves (from the base) showed an average reduction in net CO2 assimilation of 52.2 % and 48.4 %, respectively, while the 6th leaf showed a reduction of only 21.3 %. The response of grapevine photosynthesis to mite feeding seems to depend not only on mite density and duration of feeding, but also on the phenological stage of the plant. In fact, at veraison the vines showed increased tolerance to mite feeding compared with other phenological stages. At mite infestation levels of 6000 mite-days, leaves infested with T. urticae showed, as compared to uninjured leaves, an average reduction in transpiration rate of 14.4 % to 40.8 %, depending on the leaf position. The acaricides Tetradifon and Fenbutatin-oxide and the fungicide Folpet combined with Penconazol showed no effect on the gas exchange parameters
Assessment of risk of insect-resistant transgenic crops to nontarget arthropods
An international initiative is developing a scientifically rigorous approach to evaluate the potential risks to nontarget arthropods (NTAs) posed by insect-resistant, genetically modified (IRGM) crops. It adapts the tiered approach to risk assessment that is used internationally within regulatory toxicology and environmental sciences. The approach focuses on the formulation and testing of clearly stated risk hypotheses, making maximum use of available data and using formal decision guidelines to progress between testing stages (or tiers). It is intended to provide guidance to regulatory agencies that are currently developing their own NTA risk assessment guidelines for IRGM crops and to help harmonize regulatory requirements between different countries and different regions of the world
The Present and Future Role of Insect-Resistant Genetically Modified Maize in IPM
Commercial, genetically-modified (GM) maize was first planted in the United States (USA, 1996) and Canada (1997) but now is grown in 13 countries on a total of over 35 million hectares (\u3e24% of area worldwide). The first GM maize plants produced a Cry protein derived from the soil bacteriumBacillus thuringiensis (Bt), which made them resistant to European corn borer and other lepidopteran maize pests. New GM maize hybrids not only have resistance to lepidopteran pests but some have resistance to coleopteran pests and tolerance to specific herbicides. Growers are attracted to the Btmaize hybrids for their convenience and because of yield protection, reduced need for chemical insecticides, and improved grain quality. Yet, most growers worldwide still rely on traditional integrated pest management (IPM) methods to control maize pests. They must weigh the appeal of buying insect protection “in the bag” against questions regarding economics, environmental safety, and insect resistance management (IRM). Traditional management of maize insects and the opportunities and challenges presented by GM maize are considered as they relate to current and future insect-resistant products. Four countries, two that currently have commercialize Bt maize (USA and Spain) and two that do not (China and Kenya), are highlighted. As with other insect management tactics (e.g., insecticide use or tillage), GM maize should not be considered inherently compatible or incompatible with IPM. Rather, the effect of GM insect-resistance on maize IPM likely depends on how the technology is developed and used
The role of CDK9 in myogenesis
Cdk9 is a member of cyclin-dependent kinases (cdks). It is expressed in human and murine tissues with high levels in terminally differentiated cells. It is involved in the regulation of transcriptional elongation via phosphorylation of CTD of RNA polII (1). It has been demonstrated that CdK9, complexed with CyT2a, plays a role in the activation of myogenic program. Moreover Cdk9-CyT2a activity is not down-regulated in myotube formation, but its activation contributes to the transcriptional activity MyoD-mediated during myogenic program (2). Recently, a 55 kDa protein called cdk9-55 has been identified. Cdk9-55 is significantly upregulated in cells induced to differentiate, either in C2C12 cells or in satellite isolated cells. In addition, it has been demonstrated that there is a clear induction of cdk9-55 expression in injured skeletal muscles (3). In order to deepen the discussion and extend the understanding of the biological role of the two isoforms of cdk9 during skeletal muscle differentiation process, we report the role of the two isoforms during in vivo mouse myogenesis. We have analyzed the behavior of CDk9-42 and CDK9-55 in primary and secondary myogenesis. Of particular interest are the apparent inverse correlation between the two cdk9 isoforms during the events of limbs formation and how the expression of two CDK9 isoforms, in combination with specific positive (Cycline T1,T2,k) or negative regulators (7SKsnRNA/Hexim1), is associated to a specific cellular phenotype and correlated to a specific function
In vivo mature immunological synapses forming SMACs mediate clearance of virally infected astrocytes from the brain
The microanatomy of immune clearance of infected brain cells remains poorly understood. Immunological synapses are essential anatomical structures that channel information exchanges between T cell–antigen-presenting cells (APC) during the priming and effector phases of T cells' function, and during natural killer–target cell interactions. The hallmark of immunological synapses established by T cells is the formation of the supramolecular activation clusters (SMACs), in which adhesion molecules such as leukocyte function-associated antigen 1 segregate to the peripheral domain of the immunological synapse (p-SMAC), which surrounds the T cell receptor–rich or central SMAC (c-SMAC). The inability so far to detect SMAC formation in vivo has cast doubts on its functional relevance. Herein, we demonstrate that the in vivo formation of SMAC at immunological synapses between effector CD8+ T cells and target cells precedes and mediates clearance of virally infected brain astrocytes
State of malaria diagnostic testing at clinical laboratories in the United States, 2010: a nationwide survey
<p>Abstract</p> <p>Background</p> <p>The diagnosis of malaria can be difficult in non-endemic areas, such as the United States, and delays in diagnosis and errors in treatment occur too often.</p> <p>Methods</p> <p>A nationwide survey of laboratories in the United States and its nine dependent territories was conducted in 2010 to determine factors that may contribute to shortcomings in the diagnosis of malaria. This survey explored the availability of malaria diagnostic tests, techniques used, and reporting practices.</p> <p>Results</p> <p>The survey was completed by 201 participants. Ninety percent reported that their laboratories had at least one type of malaria diagnostic test available on-site. Nearly all of the respondents' laboratories performed thick and thin smears on-site; approximately 50% had access to molecular testing; and only 17% had access to rapid diagnostic tests on-site. Seventy-three percent reported fewer than five confirmed cases of malaria in their laboratory during the 12-month period preceding the survey. Twenty-eight percent stated that results of species identification took more than 24 hours to report. Only five of 149 respondents that performed testing 24 hours a day, 7 days a week complied with all of the Clinical and Laboratory Standards Institute (CLSI) guidelines for analysis and reporting of results.</p> <p>Conclusion</p> <p>Although malaria diagnostic testing services were available to a majority of U.S. laboratories surveyed, very few were in complete compliance with all of the CLSI guidelines for analysis and reporting of results, and most respondents reported very few cases of malaria annually. Laboratories' difficulty in adhering to the rigorous CLSI guidelines and their personnel's lack of practice and proficiency may account for delays and errors in diagnosis. It is recommended that laboratories that infrequently process samples for malaria seek opportunities for practice and proficiency training annually and take advantage of available resources to assist in species identification.</p
Parasite
We report the case of an 82-year-old patient, hospitalized for malaise. Her clothes were infested by numerous insects and the entomological analysis identified them as being Cimex lectularius (bed bugs). The history of the patient highlighted severe cognitive impairment. The biological assessment initially showed a profound microcytic, aregenerative, iron deficiency anemia. A vitamin B12 deficiency due to pernicious anemia (positive intrinsic factor antibodies) was also highlighted, but this was not enough to explain the anemia without macrocytosis. Laboratory tests, endoscopy and a CT scan eliminated a tumor etiology responsible for occult bleeding. The patient had a mild itchy rash which was linked to the massive colonization by the bed bugs. The C. lectularius bite is most often considered benign because it is not a vector of infectious agents. Far from trivial, a massive human colonization by bed bugs may cause such a hematic depletion that severe microcytic anemia may result
Malaria relevance and diagnosis in febrile Burkina Faso travellers: a prospective study:
BACKGROUND: There is a lack of information regarding the epidemiology of malaria among travellers from non-malaria endemic countries to Sahelian areas. The literature provides general statistics about imported malaria in industrialized countries or extensive recommendations about fever management, but none of these recommendations are applicable to developing countries. METHODS: The aim of the study was to evaluate the aetiologies of fever, malaria prevalence, and best diagnostic methods in a population of 306 non-malaria endemic travellers who, over a one-year period, consulted the French embassy's Centre Medico-Social in Ouagadougou (Burkina Faso) for fever. All patients underwent a clinical examination, a questionnaire, and three different malaria tests: thick blood film, QBC-test and HRP-2-based rapid diagnostic test. RESULTS: Fever was caused by malaria in 69 cases (23%), while 37 (12%) were due to Pneumonia and 35 cases (8%) to ENT infections. Fever remained unexplained in 87 patients (51.3%). Malaria prevalence varied throughout the year: about 90% of malaria cases were diagnosed during and after the rainy season, between July and December, with up to 50% malaria prevalence for fever cases in October. Malaria diagnosis based solely on clinical signs, combined or not, leads to about 80% of unnecessary treatments.Although anti-malarial chemoprophylaxis was used in only 69% of short-stay patients (who travelled for less than three months), this was effective. Under local conditions, and using blood film examination as the reference method, the QBC test appeared to be more reliable than the HRP-2-based rapid diagnostic test, with respective sensitivities of 98.6% versus 84.1%, and specificities of 99.6% versus 98.3%. CONCLUSIONS: Reliable biological diagnosis of malaria among travellers from non-malaria endemic countries in Sahelian areas is necessary because of low malaria prevalence and the poor performance of clinical diagnosis. A fever during the first half of the year requires investigating another aetiology, particularly a respiratory one. Malaria chemoprophylaxis is efficient and must not be overlooked. The QBC test appears to be the most reliable diagnostic test in this context
Genetic Alterations in Gliomas Remodel the Tumor Immune Microenvironment and Impact Immune-Mediated Therapies
High grade gliomas are malignant brain tumors that arise in the central nervous system, in patients of all ages. Currently, the standard of care, entailing surgery and chemo radiation, exhibits a survival rate of 14-17 months. Thus, there is an urgent need to develop new therapeutic strategies for these malignant brain tumors. Currently, immunotherapies represent an appealing approach to treat malignant gliomas, as the pre-clinical data has been encouraging. However, the translation of the discoveries from the bench to the bedside has not been as successful as with other types of cancer, and no long-lasting clinical benefits have been observed for glioma patients treated with immune-mediated therapies so far. This review aims to discuss our current knowledge about gliomas, their molecular particularities and the impact on the tumor immune microenvironment. Also, we discuss several murine models used to study these therapies pre-clinically and how the model selection can impact the outcomes of the approaches to be tested. Finally, we present different immunotherapy strategies being employed in clinical trials for glioma and the newest developments intended to harness the immune system against these incurable brain tumors.Fil: Garcia Fabiani, Maria Belen. University of Michigan; Estados Unidos. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Haase, Santiago. University of Michigan; Estados Unidos. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Comba, Andrea. University of Michigan; Estados Unidos. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Carney, Stephen. University of Michigan; Estados UnidosFil: McClellan, Brandon. University of Michigan; Estados UnidosFil: Banerjee, Kaushik. University of Michigan; Estados UnidosFil: Alghamri, Mahmoud S.. University of Michigan; Estados UnidosFil: Syed, Faisal. University of Michigan; Estados UnidosFil: Kadiyala, Padma. University of Michigan; Estados UnidosFil: Nuñez, Felipe. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Bioquímicas de Buenos Aires. Fundación Instituto Leloir. Instituto de Investigaciones Bioquímicas de Buenos Aires; ArgentinaFil: Candolfi, Marianela. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Biomédicas. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Biomédicas; ArgentinaFil: Asad, Antonela Sofía. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Biomédicas. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Biomédicas; ArgentinaFil: González, Nazareno. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Biomédicas. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Biomédicas; ArgentinaFil: Aikins, Marisa E.. University of Michigan; Estados UnidosFil: Schwendeman, Anna. University of Michigan; Estados UnidosFil: Moon, James J.. University of Michigan; Estados UnidosFil: Lowenstein, Pedro R.. University of Michigan; Estados UnidosFil: Castro, Maria G.. University of Michigan; Estados Unido
First case of human gongylonemosis in France
Gongylonema spp. are cosmopolitan spirurid nematodes that are common parasites of wild and domesticated mammals and birds. Gongylonema pulchrum Molin, 1857 is most common in ruminants, where it invades mucosa and submucosa of the mouth, tongue, oesophagus and forestomachs. It extremely rarely occurs in man, and fewer than 60 cases have been reported worldwide. We report a case from the Alsace region, which appears to be the first case of human gongylonemosis described in France.
Les nématodes du genre Gongylonema sont des spiruridés cosmopolites parasites fréquents dans de nombreux mammifères et oiseaux sauvages ou domestiques. Gongylonema pulchrum Molin, 1857 est l’espèce la plus souvent rapportée chez les ruminants, dans la muqueuse et la sous-muqueuse de leur bouche, langue, œsophage et rumen. Il n’est que très exceptionnellement retrouvé chez l’homme. Moins de 60 cas ont été décrits à travers le monde. Nous rapportons dans cet article le premier cas français, découvert en Alsace
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