101 research outputs found
Bioreactor production process of Spodoptera frugiperda multiple nucleopolyhedrovirus biopesticide.
ABSTRACT - Spodoptera frugiperda (fall armyworm) is one of the most important maize pests in the world and the baculovirus Spodoptera frugiperda multiple nucleopolyhedrovirus (SfMNPV), a natural pathogen of this pest, has been used as a biopesticide for its control. At present, in vivo strategies at the commercial scale are employed by multiplying the virus in the host insect in biofactory facilities; however, in vitro large-scale production is an interesting alternative to overcome the limitations of baculoviruses massal production. This study aimed to develop the process of the SfMNPV in vitro production by evaluating the effects of different multiplicities of infection (MOI) and nutritional supplements, morphological and molecular analysis of the infection on the growth of Sf9 cells and virus production. The Bioreactor Stirred Tank Reactor (STR) approach with glutamine-supplemented Sf-900 III serum free culture medium, combined with the MOI of 1.0, showed the best viral production performance, with a specific productivity above 300 occlusion bodies (OBs)/cell and volumetric productivity of 9.0 x 10¹¹ OBs/L
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Biodegradation of the herbicide mecoprop-p with soil depth and its relationship with class III tfdA genes
Mecoprop-p [(R)-2-(4-chloro-2-methylphenoxy) propanoic acid) is widely used 37 in agriculture and poses an environmental concern because of its susceptibility to leach 38 from soil to water. We investigated the effect of soil depth on mecoprop-p 39 biodegradation and its relationship with the number and diversity of tfdA related genes, 40 which are the most widely known genes involved in degradation of the 41 phenoxyalkanoic acid group of herbicides by bacteria. Mecoprop-p half-life (DT50) was 42 approximately 12 days in soil sampled from <30 cm depth, and increased progressively 43 with soil depth, reaching over 84 days at 70-80 cm. In sub-soil there was a lag period of 44 between 23 and 34 days prior to a phase of rapid degradation. No lag phase occurred in 45 top-soil samples prior to the onset of degradation. The maximum degradation rate was 46 the same in top-soil and sub-soil samples. Although diverse tfdAα and tfdA genes were 47 present prior to mecoprop-p degradation, real time PCR revealed that degradation was 48 associated with proliferation of tfdA genes. The number of tfdA genes and the most 49 probable number of mecoprop-p degrading organisms in soil prior to mecoprop-p 50 addition were below the limit of quantification and detection respectively. Melting 51 curves from the real time PCR analysis showed that prior to mecoprop-p degradation 52 both class I and class III tfdA genes were present in top- and sub-soil samples. However 53 at all soil depths only tfdA class III genes proliferated during degradation. Denaturing 54 gradient gel electrophoresis confirmed that class III tfdA genes were associated with 55 mecoprop-p degradation. Degradation was not associated with the induction of novel 56 tfdA genes in top- or sub-soil samples, and there were no apparent differences in tfdA 57 gene diversity with soil depth prior to or following degradation
Infections caused by filamentous fungi in patients with hematologic malignancies. A report of 391 cases by GIMEMA Infection Program.
BACKGROUND AND OBJECTIVES: To evaluate the clinical characteristics of patients with hematologic malignancies developing a filamentous fungi infection (FFI) and to define the prognostic factors for their outcome.
DESIGN AND METHODS: A retrospective study, conducted on patients admitted to 14 Hematology divisions of tertiary care or university hospitals, participating in the GIMEMA Infection Program, over a ten-year period (1988-1997). The study included patients with hematological malignancies and a histologically and/or microbiologically proven or probable FFI.
RESULTS: We included 391 patients (male/female: 262/129, median age 49 years) with hematologic malignancies (225 acute myeloid leukemia, 67 acute lymphocytic leukemia, 30 chronic myeloid leukemia, 22 non-Hodgkin's lymphoma, 12 myelodysplastic syndrome, 10 aplastic anemia, 7 Hodgkin's disease, 8 chronic lymphocytic leukemia, 5 multiple myeloma, and 5 hairy cell leukemia) who developed a proven FFI. Eighty percent of the patients had been neutropenic for an average of 14 days before the infection, and 71% had an absolute neutrophil count lower than 0.5 x 10(9)/L at the time of FFI diagnosis. The primary sites of infection were: lungs (85%), nose and paranasal sinus (10%), and other sites (5%). The diagnosis was made while still alive in 310 patients (79%), and at autopsy in the remaining 81 patients (21%). Chest X-ray was diagnostic in 77% of patients with pulmonary FFI, while computed tomography (CT) scan of the thorax was positive in 95% of cases. A significant diagnostic advantage for CT scan was observed in 145 patients who had both a chest X-ray and CT scan. Aspergillus was identified as the cause of FFI in 296 patients, Mucorales in 45 patients, Fusarium in 6 patients and other filamentous fungi species in 4 patients, while in a further 40 patients no agent was identifiable. The overall mortality rate three months after the diagnosis of FFI was 74%, and fungal infection had been the cause of death in 51% of patients.
INTERPRETATION AND CONCLUSIONS: Our retrospective study shows that FFI still remains a life-threatening complication in neutropenic patients. Despite appropriate treatment, half of the patients die due to this complication. The use of glucocorticoids and recovery from neutropenia are the most important prognostic factors. Mucorales infections are associated with a significantly poorer prognosis than those due to Aspergillus spp
Doctoral student experience in Education: Activities and difficulties influencing identity development
This paper explores variation in the events or activities Education doctoral students describe as contributing to their feeling of being an academic or belonging to an academic community as well as difficulties they experience. The results (drawing principally on students in a Canadian research-intensive university though with some in a UK university) demonstrate a rich variation in multiple formative activities that are experienced as contributing to a developing identity as an academic, with many lying outside formal and semi-formal aspects of the doctorate. Yet, at the same time students report tensions in the very sorts of activities they often find significant and positive in the development of their identity. We see this analysis as offering much-needed insights into the formative role of cumulative day-to-day activities in the development of academic identity
Mindfulness, Compassion, and Self-Compassion as Moderator of Environmental Support on Competency in Mental Health Nursing
Abstract: This research explored the established relationship between environmental support and competency for Mental Health Nurses, intending to investigate whether the tendency to display higher levels of mindfulness, compassion, and self-compassion might buffer the effect of a poor environment on competency. One questionnaire was comprised of five pre-developed questionnaires, which included all items examining environmental support, competency, mindfulness, compassion, and self-compassion. Mental Health Nurses (n = 103) were recruited from online forums and social media group pages in the UK. The result showed environmental support related positively to competency. Furthermore, the positive relationship of competency with environmental support was moderated when controlling for compassion but did not with mindfulness and self-compassion, although subscales showed some further interactions. When poor environmental support influences the competency of mental health professionals, compassion and mindfulness-based interactions may have the potential to uphold competency
Reducibility condition for nonlinear discrete-time systems: behavioral approach
The paper addresses the problem of reducibility of nonlinear discrete-time systems, described by implicit higher order difference equations where no a priori distinction is made between input and output variables. The reducibility definition is based on the concept of autonomous element. We prove necessary reducibility condition, presented in terms of the left submodule, generated by the row matrix, describing the behavior of the linearized system, over the ring of left difference polynomials. Then the reducibility of the system implies the closedness of the submodule, like in the linear time-invariant case. In the special case, when the variables may be specified as inputs and outputs and the system equations are Niven in the explicit form, the results of this paper yield the known results
Realization of nonlinear composite systems
The paper studies the realization problem for series and parallel connections of nonlinear single-input single-output systems, described by higher order differential equations. Necessary and sufficient conditions are given for the existence of the classical state space realization in both cases. It is proved that post- and parallel compensators are of no help in overcoming non-realizability. Results are illustrated by an example
The effect of dissolved oxygen concentration control on cell growth and antibiotic retamycin production in Streptomyces olindensis So20 fermentations
Cell growth and retamycin production in Streptomyces olindensis So20 were studied at different dissolved oxygen levels during fermentation. The profiles for cell growth and retamycin production in an experiment with dissolved oxygen control at 5% air saturation during production were similar to those in an experiment without dissolved oxygen control. However, despite slower cell growth, a twofold increase in the final retamycin concentration was achieved when dissolved oxygen was controlled at 100% during the growth phase, compared to a base experiment (no DO control). Therefore, the results revealed that retamycin production was dependent on dissolved oxygen concentration during the growth phase, even with sufficient oxygen. On the other hand, a large oxygen supply during the production phase did not contribute to an improvement in retamycin production
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