992 research outputs found
Arginine biosynthesis and utilization in maritime pine
Vegetative propagation through somatic embryogenesis in combination with the cryopreservation
of embryogenic lines is a major tool in conifer biotechnology. An important process during the
maturation phase of embryogenesis is the biosynthesis and deposition of storage proteins. The
accumulation of some abundant storage proteins in maturing cotyledonary somatic embryos (SE)
is much lower than in mature zygotic embryos (ZE) showing an important influence of storage
compounds on the quality of SE. Arginine constitutes a large portion of the amino acid pool in
storage proteins of conifers and therefore arginine biosynthesis and utiization is a relevant
metabolic pathway during pine embryogenesis and early growth.
Research in our laboratory is focused on maritime pine (Pinus pinaster Ait.), a broadly planted
conifer species in France, Spain and Portugal where it is distributed over approximately 4 million
hectares. This conifer species is also one of the most advanced model trees for genetic and
phenotypic studies and a large number of molecular and transcriptomic resources are currently
available.
With the aim to understand the molecular basis of the differential accumulation of storage proteins
in SE and ZE, the arginine metabolic pathway has been studied in maritime pine, in collaboration
with the French private institute FCBA. A general overview of this research programme will be
presented and discussed. The knowledge acquired from our studies will help to refine
biotechnological procedures for clonal propagation of conifers via somatic embryogenesis.
Funding support by:The Spanish Ministerio de Economía y Competitividad (BIO2015-69285-R)
and Junta de Andalucía (BIO-474). And the French Ministry of Agriculture (DGAL, N°2014-352,
QuaSeGraine project). The project also benefited from the technical support of the
XYLOBIOTECH facility (ANR-10-EQPX-16 XYLOFOREST).Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech
Influence of IFNL3/4 polymorphisms on the incidence of cytomegalovirus infection after solid-organ transplantation
Background. Polymorphisms in the interferon-λ (IFNL) 3/4 region have been associated with reduced hepatitis C virus clearance. We explored the role of such polymorphisms on the incidence of CMV infection in solid-organ transplant (SOT) recipients. Methods. Caucasian patients participating in the Swiss Transplant Cohort Study in 2008-2011 were included. A novel functional TT/-G polymorphism (rs368234815) in the CpG region upstream of IFNL3 was investigated. Results. A total of 840 SOT recipients at risk for CMV were included, among whom 373 (44%) received antiviral prophylaxis. The 12-months cumulative incidence of CMV replication and disease were 0.44 and 0.08, respectively. Patient homozygous for the minor rs368234815 allele (-G/-G) tended to have a higher cumulative incidence of CMV replication (SHR=1.30 [95%CI 0.97-1.74], P=0.07) compared to other patients (TT/TT or TT/-G). The association was significant among patients followed by a preemptive approach (SHR=1.46 [1.01-2.12], P=0.047), especially in patients receiving an organ from a seropositive donor (D+, SHR=1.92 [95%CI 1.30-2.85], P=0.001), but not among those who received antiviral prophylaxis (SHR=1.13 [95%CI 0.70-1.83], P=0.6). These associations remained significant in multivariate competing risk regression models. Conclusions. Polymorphisms in the IFNL3/4 region influence susceptibility to CMV replication in SOT recipients, particularly in patients not receiving antiviral prophylaxi
Relevant microclimate for determining the development rate of malaria mosquitoes and possible implications of climate change
Background The relationship between mosquito development and temperature is one of the keys to understanding the current and future dynamics and distribution of vector-borne diseases such as malaria. Many process-based models use mean air temperature to estimate larval development times, and hence adult vector densities and/or malaria risk. Methods Water temperatures in three different-sized water pools, as well as the adjacent air temperature in lowland and highland sites in western Kenya were monitored. Both air and water temperatures were fed into a widely-applied temperature-dependent development model for Anopheles gambiae immatures, and subsequently their impact on predicted vector abundance was assessed. Results Mean water temperature in typical mosquito breeding sites was 4-6°C higher than the mean temperature of the adjacent air, resulting in larval development rates, and hence population growth rates, that are much higher than predicted based on air temperature. On the other hand, due to the non-linearities in the relationship between temperature and larval development rate, together with a marginal buffering in the increase in water temperature compared with air temperature, the relative increases in larval development rates predicted due to climate change are substantially less. Conclusions Existing models will tend to underestimate mosquito population growth under current conditions, and may overestimate relative increases in population growth under future climate change. These results highlight the need for better integration of biological and environmental information at the scale relevant to mosquito biology
A Spatial Model of Mosquito Host-Seeking Behavior
Mosquito host-seeking behavior and heterogeneity in host distribution are important factors in predicting the transmission dynamics of mosquito-borne infections such as dengue fever, malaria, chikungunya, and West Nile virus. We develop and analyze a new mathematical model to describe the effect of spatial heterogeneity on the contact rate between mosquito vectors and hosts. The model includes odor plumes generated by spatially distributed hosts, wind velocity, and mosquito behavior based on both the prevailing wind and the odor plume. On a spatial scale of meters and a time scale of minutes, we compare the effectiveness of different plume-finding and plume-tracking strategies that mosquitoes could use to locate a host. The results show that two different models of chemotaxis are capable of producing comparable results given appropriate parameter choices and that host finding is optimized by a strategy of flying across the wind until the odor plume is intercepted. We also assess the impact of changing the level of host aggregation on mosquito host-finding success near the end of the host-seeking flight. When clusters of hosts are more tightly associated on smaller patches, the odor plume is narrower and the biting rate per host is decreased. For two host groups of unequal number but equal spatial density, the biting rate per host is lower in the group with more individuals, indicative of an attack abatement effect of host aggregation. We discuss how this approach could assist parameter choices in compartmental models that do not explicitly model the spatial arrangement of individuals and how the model could address larger spatial scales and other probability models for mosquito behavior, such as Lévy distributions
The Moore-Penrose Pseudoinverse. A Tutorial Review of the Theory
In the last decades the Moore-Penrose pseudoinverse has found a wide range of
applications in many areas of Science and became a useful tool for physicists
dealing, for instance, with optimization problems, with data analysis, with the
solution of linear integral equations, etc. The existence of such applications
alone should attract the interest of students and researchers in the
Moore-Penrose pseudoinverse and in related sub jects, like the singular values
decomposition theorem for matrices. In this note we present a tutorial review
of the theory of the Moore-Penrose pseudoinverse. We present the first
definitions and some motivations and, after obtaining some basic results, we
center our discussion on the Spectral Theorem and present an algorithmically
simple expression for the computation of the Moore-Penrose pseudoinverse of a
given matrix. We do not claim originality of the results. We rather intend to
present a complete and self-contained tutorial review, useful for those more
devoted to applications, for those more theoretically oriented and for those
who already have some working knowledge of the sub ject.Comment: 23 page
Multisensory body representation in autoimmune diseases
Body representation has been linked to the processing and integration of multisensory signals. An outstanding example of the pivotal role played by multisensory mechanisms in body representation is the Rubber Hand Illusion (RHI). In this paradigm, multisensory stimulation induces a sense of ownership over a fake limb. Previous work has shown high interindividual differences in the susceptibility to the RHI. The origin of this variability remains largely unknown. Given the tight and bidirectional communication between the brain and the immune system, we predicted that the origin of this variability could be traced, in part, to the immune system's functioning, which is altered by several clinical conditions, including Coeliac Disease (CD). Consistent with this prediction, we found that the Rubber Hand Illusion is stronger in CD patients as compared to healthy controls. We propose a biochemical mechanism accounting for the dependency of multisensory body representation upon the Immune system. Our finding has direct implications for a range of neurological, psychiatric and immunological conditions where alterations of multisensory integration, body representation and dysfunction of the immune system co-exist
Spatio-temporal distribution of pyrethroids in soil in Mediterranean paddy fields
[EN] The demand of rice by the increase in population in many countries has intensified the application of pesticides and the use of poor quality water to irrigate fields. The terrestrial environment is one compartment affected by these situations, where soil is working as a reservoir, retaining organic pollutants. Therefore, it is necessary to develop methods to determine insecticides in soil and monitor susceptible areas to be contaminated, applying adequate techniques to remediate them.
Materials and methods
This study investigates the occurrence of ten pyrethroid insecticides (PYs) and its spatio-temporal variance in soil at two different depths collected in two periods (before plow and during rice production), in a paddy field area located in the Mediterranean coast. Pyrethroids were quantified using gas chromatography mass spectrometry (GC MS) after ultrasound-assisted extraction with ethyl acetate. The results obtained were assessed statistically using non-parametric methods, and significant statistical differences (p < 0.05) in pyrethroids content with soil depth and proximity to wastewater treatment plants were evaluated. Moreover, a geographic information system (GIS) was used to monitor the occurrence of PYs in paddy fields and detect risk areas.
Results and discussion
Pyrethroids were detected at concentrations ≤57.0 ng g−1 before plow and ≤62.3 ng g−1 during rice production, being resmethrin and cyfluthrin the compounds found at higher concentrations in soil. Pyrethroids were detected mainly at the top soil, and a GIS program was used to depict the obtained results, showing that effluents from wastewater treatment plants (WWTPs) were the main sources of soil contamination. No toxic effects were expected to soil organisms, but it is of concern that PYs may affect aquatic organisms, which represents the worst case scenario.
Conclusions
A methodology to determine pyrethroids in soil was developed to monitor a paddy field area. The use of water from WWTPs to irrigate rice fields is one of the main pollution sources of pyrethroids. It is a matter of concern that PYs may present toxic effects on aquatic organisms, as they can be desorbed from soil. Phytoremediation may play an important role in this area, reducing the possible risk associated to PYs levels in soil.Authors wish to thank INIA for the predoctoral fellowship (R. Aznar) and Spanish Ministry of Economy and Competitiveness RTA2014-00012-C03-01 for financial support and Jonathan Villanueva Martin for his contribution to this work.Aznar, R.; Moreno-Ramón, H.; Albero, B.; Sánchez Brunete, C.; Tadeo, JL. (2016). Spatio-temporal distribution of pyrethroids in soil in Mediterranean paddy fields. 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J Hydrol 393(3-4):156–162Fojut TL, Palumbo AJ, Tjeerdema RS (2012) Aquatic life water quality criteria derived via the UC Davis method: II. Pyrethroid insecticides. Rev Environ Contam Toxicol 216:51–103Gan J, Lee SJ, Liu WP, Haver DL, KAbashima JN (2005) Distribution and persistence of pyrethroids in runoff sediments. J Environ Qual 34:836–841Hill IR (1985) Aquatic organisms and pyrethroids. Pestic Sci 27:429–465Huang LM, Thompson A, Zhang GL, Chen LM, Han GZ, Gong ZT (2015) The use of chronosequences in studies of paddy soil evolution: a review. Geoderma 237:199–210Katagi T (2004) Photodegradation of pesticides on plant and soil surfaces. Rev Environ Contam Toxicol 182:1–189Laskowski DA (2002) Physical and chemical properties of pyrethroids. Rev Environ Contam Toxicol 174:49–170Mahabali S, Spagnoghe P (2014) Mitigation of two insecticides by wetlands plants: feasibility study for the treatment of agricultural runoff in Suriname (South America). Water Air Soil Pollut 225:1771Maund SJ, Hamer MJ, Lane MCG, Farrelly E, Rapley JH, Goggin UM, Gentle WE (2002) Partitioning, bioavailability, and toxicity of the pyrethroid insecticide cypermethrin in sediments. Environ Toxicol Chem 21(1):9–15Maund SJ, Campbell PJ, Giddings JM, Hamer MJ, Henry K, Pilling ED, Warinton JS, Wheeler JR (2012) Ecotoxicology of synthetic pyrethroids. Top Curr Chem 314:137–165Money E, Carter GP, Serre ML (2009) Using river distances in the space/time estimation of dissolved oxygen along two impaired river networks in New Jersey. Water Res 43(7):1948–1958Moore MT, Cooper CM, Smith S, Jr Cullum RF, Knight SS, Locke MA, Bennett ER (2009) Mitigation of two pyrethroid insecticides in Mississippi Delta constructed wetland. Environ Pollut 157:250–256Moreno-Ramón H, Marqués-Mateu A, Ibáñez-Asensio S, Gisbert JM (2015) Wetland soils under rice management and seawater intrusion: characterization and classification. 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Splice site SNPs of phospholipase PLCXD3 are significantly associated with variant and sporadic Creutzfeldt-Jakob disease
BACKGROUND: Variant Creutzfeldt-Jakob disease is an infectious, neurodegenerative, protein-misfolding disease, of the prion disease family, originally acquired through ingestion of meat products contaminated with bovine spongiform encephalopathy (BSE). Public health concern was increased by the discovery of human-to-human transmission via blood transfusion. This study has verified a novel genetic marker linked to disease risk. METHODS: SNP imputation and association testing indicated those genes that had significant linkage to disease risk and one gene was investigated further with Sanger resequencing. Results from variant Creutzfeldt-Jakob disease were compared with those from sporadic (idiopathic) Creutzfeldt-Jakob disease and published controls. RESULTS: The most significant disease risk, in addition to the prion protein gene, was for the phosphatidylinositol-specific phospholipase C, X domain containing 3 (PLCXD3) gene. Sanger resequencing of CJD patients across a region of PLCXD3 with known variants confirmed three SNPs associated with variant and sporadic CJD. CONCLUSIONS: These data provide the first highly significant confirmation of SNP allele frequencies for a novel CJD candidate gene providing new avenues for investigating these neurodegenerative prion diseases. The phospholipase PLCXD3 is primarily expressed in the brain and is associated with lipid catabolism and signal transduction
Topography and malaria transmission heterogeneity in western Kenya highlands: prospects for focal vector control
BACKGROUND: Recent resurgence of malaria in the highlands of Western Kenya has called for a more comprehensive understanding of the previously neglected complex highland vector ecology. Besides other drivers of malaria epidemiology, topography is likely to have a major effect on spatial vector and parasite distribution. The aim of this study was to determine the effects of topography on malaria spatial vector distribution and parasite prevalence. METHODOLOGY: Indoor resting adult malaria vectors and blood parasites were collected in three villages along a 4 km transect originating from the valley bottom and ending at the hilltop for 13 months. Members of the Anopheles gambiae complex were identified by PCR. Blood parasites were collected from children 6–13 years old and densities categorized by site of home location and age of the children. RESULTS: Ninety eight percent (98%) of An. gambiae s.s. and (99%) Anopheles funestus were collected in houses located at the edge of the valley bottom, whereas 1% of An. gambiae s.s. were collected at mid hill and at the hilltop respectively. No An. funestus were collected at the hilltop. Malaria prevalence was 68% at the valley bottom, 40.2% at mid hill and 26.7% at the hilltop. Children aged six years and living at the edge of the valley bottom had an annual geometric mean number of 66.1 trophozoites for every 200 white blood cells, while those living at mid-hill had a mean of 84.8, and those living at hilltop had 199.5 trophozoites. CONCLUSION: Malaria transmission in this area is mainly confined to the valley bottom. Effective vector control could be targeted at the foci. However, the few vectors observed at mid-hill maintained a relatively high prevalence rate. The higher variability in blood parasite densities and their low correlation with age in children living at the hilltop suggests a lower stability of transmission than at the mid-hill and valley bottom
Cathepsin D SNP associated with increased risk of variant Creutzfeldt-Jakob disease
<p>Abstract</p> <p>Background</p> <p>Variant Creutzfeldt-Jakob disease (vCJD) originally resulted from the consumption of foodstuffs contaminated by bovine spongiform encephalopathy (BSE) material, with 163 confirmed cases in the UK to date. Many thousands are likely to have been exposed to dietary infection and so it is important (for surveillance, epidemic modelling, public health and understanding pathogenesis) to identify genetic factors that may affect individual susceptibility to infection. This study looked at a polymorphism in the cathepsin D gene (refSNP ID: rs17571) previously examined in Alzheimer's disease (AD).</p> <p>Methods</p> <p>Blood samples taken from 110 vCJD patients were tested for the C-T base change, and genotype data were compared with published frequencies for a control population using multiple logistic regression.</p> <p>Results</p> <p>There was a significant excess of the cathepsin D polymorphism TT genotype in the vCJD cohort compared to controls. The TT genotype was found to have a 9.75 fold increase in risk of vCJD compared to the CT genotype and a 10.92 fold increase compared to the CC genotype.</p> <p>Conclusion</p> <p>This mutation event has been observed to alter the protease activity of the cathepsin D protein and has been linked to an increase in amyloid beta plaque formation in AD. vCJD neuropathology is characterised by the presence of amyloid plaques, formed from the prion protein, and therefore alterations in the amyloid processing activity of cathepsin D may affect the neuropathogenesis of this disease.</p
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