Effect Of Host Plant On The Fecundity Of Spittlebug Deois Flavopicta Stal (homoptera: Cercopidae): Implications On Population Dynamics

The spittlebug Deois flavopicta Stal (Hom.: Cercopidae) occurs naturally on native grasses in Central Brazil in low population densities. After the introduction of African grasses, mainly of the genus Brachiaria, for cattle raising, D. flavopicta began to produce population outbreaks and became a pest. Two studies were conducted, aiming to estimate the effects of a native and an exotic host plant on the fecundity of this insect. Females of D. flavopicta maintained during the adult stage on Brachiaria ruziziensis produced more eggs and lived longer than those maintained on Axonopus marginatus (a native grass widely distributed in Brazil), independently of the host plant on which the nymphs were reared. Due to the severe damage produced by adult D. flavopicta on the host plant, the effect of insect density on its own reproductive capacity was evaluated in oviposition cages containing plants of B. ruziziensis, standardized in height and stem number. Densities of one, two, three, four and six couples with virgin females were evaluated. Population densities of three couples, equivalent to 150 adults/m2, or higher decreased insect's fecundity. These results contributed to the understanding of the mechanisms that determine low levels of spittlebug populations in the native grasses and promote population outbreaks in introduced ones.304547552Begon, M., Mortimer, M., (1986) Population Ecology: A Unified Study of Animals and Plants. 2nd Ed., , Oxford, Blackwell, 220pBerryman, A.A., The theory and classification of outbreaks (1987) Insect Outbreaks, pp. 3-28. , P. Barbosa & J.C. Schultz (eds.), New York, Academic Pres, 578pBoddey, R.M., Victoria, R.L., Estimation of biological nitrogen fixation associated with Brachiaria and Paspalum grasses using 15N labelled organic matter and fertilizer (1986) Plant Soil, 90, pp. 265-313Cavalcante, P.B., Contribuição ao estudo dos corpos silicosos das gramíneas amazônicas (1968) Botânica, 30, pp. 1-26Döbereiner, J., Pedrosa, F.O., (1987) Nitrogen-fixing Bacteria in Nonleguminous Crop Plants, , New York, Spring-Verlag, 155pFontes, E.M.G., Pires, C.S., Sujii, E.R., Mixed risk-spreading strategies and the population dynamics of a brazilian pasture pest, Deois flavopicta (Homoptera: Cercopidae) (1995) J. Econ. Entomol., 88, pp. 1256-1262Ferrufino, A., Lapointe, S.L., Host plant resistance in Brachiaria grasses to the spittlebug Zulia colombiana (1989) Entomol. Exp. Appl., 51, pp. 155-162Haukioja, E., Effects of food and predation on population dynamics (1993) Caterpillars: Ecological and Evolutionary Constraints on Foraging, pp. 425-447. , N.E. Stamp & T.M. Casey (eds.), New York, Chapman and Hall, 587pHewitt, G.B., Enviromental factors affecting spittlebug egg survival during the dry season in Central Brazil (1986) Pesq. Agropec. Bras., 21, pp. 1237-1243Hewitt, G.B., Nilakhe, S.S., Enviromental factors affecting the survival of eggs and early instar nymphs of spittlebugs Zulia entreriana and Deois flavopicta during the rainy season in central Brazil (1986) An. Soc. Entomol. Brasil, 15, pp. 61-76Klink, C.A., Effects of clipping on size and tillering of native and African grasses of Brazilian savannas (the cerrado) (1984) Oecologia, 70, pp. 365-376Kuo, J., Fox, E., MacDonald, S., (1992) Sigmastat: Statistical Software for Working Scientist. User's Manual, , San Francisco, Jandel ScientificMelo, L.A.A., Silveira Neto, S., Villa Nova, N.A., Reis, P.R., Influência de elementos climáticos sobre a população de cigarrinhas das pastagens (1984) Pesq. Agropec. Bras., 19, pp. 9-19De Menezes, M., El Khadi, M.K., Pereira, J.M., Ruiz, M.A.M., (1983) Bases para O Controle Integrado Das Cigarrinhas-das-pastagens Na Região Sudeste Da Bahia, , CEPLAC-CEPEC, Ilhéus, 33pMilanez, J.M., Parra, J.R.P., Menezes, M., Influência de alguns fatores climáticos nas flutuações populacionais de Zulia entreriana (Berg, 1879) e Deois flavopicta (Stal, 1854) nas regiões de Nova Odessa e Piracicaba, Estado de São Paulo (1981) Rev. Theobroma, 11, pp. 219-228Oomen, P.A., A population study of the spittle bugs Aeneolamia occidentalis (Walk.) and Prosapia simulans (Walk.) (Homoptera: Cercopidae) in Mexican Pangola pastures (1975) Z. Ang. Entomol., 79, pp. 225-238Pacheco, J.M., (1981) Aspectos Da Biologia e Ecologia de Deois Flavopicta (Stal, 1854) (Homoptera: Cercopidae) Na Região de São Carlos, , Tese de doutorado, UFSCa, São Paulo, 111pPires, C.S.S., Sujii, E.R., Fontes, E.M.G., Tauber, C.A., Tauber, M.J., Dry-season dormancy in eggs of Deois flavopicta (Homoptera: Cercopidae): Roles of temperature and moisture in nature (2000) Environ. Entomol., 29, pp. 714-720Pires, C.S.S., Price, P.W., Fontes, E.G., Preference performance linkage in the neotropical spittlebug Deois flavopicta, and its relation to the phylogenetic constraints hypothesis (2000) Ecol. Entomol., 25, pp. 71-80Pires, C.S.S., Price, P.W., Oliveira, R.C., Distribution of the spitttlebug Deois flavopicta (Homoptera: Cercopidae) on wild and cultivated host species (2000) An. Soc. Entomol. Brasil, 29, pp. 401-412Raven, J.A., Phytophages of xylem and phloem: A comparison of animal and plant sap-feeders (1983) Adv. Ecol. Res., 13, pp. 135-234Sanders, C.J., Knight, F.B., Natural regulation of the aphid Pterocomma populifoliae on bigtooth aspen in northern lower Michigan (1968) Ecology, 49, pp. 234-244Sendulsky, T., Labouriau, L.G., Corpos silicosos de gramíneas dos Cerrados - I (1966) An. Acad. Bras. Ciênc., 38, pp. 159-185Stoporoli-Neto, A., Pacheco, J.M., Motta, L., Pavan, C., Métodos de obtenção de ovos de cigarrinhas-das-pastagens Deois spp. (Homoptera: Cercopidae) (1985) Rev. Bras. Entomol., 29, pp. 523-533Sujii, E.R., Garcia, M.A., Fontes, E.M.G., Carvalho, V., Efeito da temperatura e umidade sobre o término diapausa de ovos e densidade populacional da cigarrinha-das-pastagens, Deois flavopicta (Stal) (Homoptera: Cercopidae) (1995) An. Soc. Entomol. Brasil, 24, pp. 465-478Sujii, E.R., (1998) Modelagem e Simulação Da Dinâmica Populacional Da Cigarrinha-das-pastagens, Deois Flavopicta (Homoptera: Cercopidae), , Tese de doutorado, Universidade Estadual de Campinas UNICAMP, Campinas, SP, 239pThompson, V., Spittlebug indicators of nitrogen-fixing plants (1994) Ecol. Entomol., 19, pp. 391-398Valério, J.R., Spittlebugs: Important pasture pests in Brazil (1988) Tymbal, 12, pp. 14-1

Habenular expression of rare missense variants of the β4 nicotinic receptor subunit alters nicotine consumption

The CHRNA5-CHRNA3-CHRNB4 gene cluster, encoding the {alpha}5, {alpha}3, and {beta}4 nicotinic acetylcholine receptor (nAChR) subunits, has been linked to nicotine dependence. The habenulo-interpeduncular (Hb-IPN) tract is particularly enriched in {alpha}3{beta}4 nAChRs. We recently showed that modulation of these receptors in the medial habenula (MHb) in mice altered nicotine consumption. Given that {beta}4 is rate-limiting for receptor activity and that single nucleotide polymorphisms (SNPs) in CHRNB4 have been linked to altered risk of nicotine dependence in humans, we were interested in determining the contribution of allelic variants of {beta}4 to nicotine receptor activity in the MHb. We screened for missense SNPs that had allele frequencies >0.0005 and introduced the corresponding substitutions in Chrnb4. Fourteen variants were analyzed by co-expression with {alpha}3. We found that {beta}4A90I and {beta}4T374I variants, previously shown to associate with reduced risk of smoking, and an additional variant {beta}4D447Y, significantly increased nicotine-evoked current amplitudes, while {beta}4R348C, the mutation most frequently encountered in sporadic amyotrophic lateral sclerosis (sALS), showed reduced nicotine currents. We employed lentiviruses to express {beta}4 or {beta}4 variants in the MHb. Immunoprecipitation studies confirmed that {beta}4 lentiviral-mediated expression leads to specific upregulation of {alpha}3{beta}4 but not {beta}2 nAChRs in the Mhb. Mice injected with the {beta}4-containing virus showed pronounced aversion to nicotine as previously observed in transgenic Tabac mice overexpressing Chrnb4 at endogenous sites including the MHb. Habenular expression of the {beta}4 gain-of-function allele T374I also resulted in strong aversion, while transduction with the {beta}4 loss-of function allele R348C failed to induce nicotine aversion. Altogether, these data confirm the critical role of habenular {beta}4 in nicotine consumption, and identify specific SNPs in CHRNB4 that modify nicotine-elicited currents and alter nicotine consumption in mice

Structure-function studies can improve binding affinity of cohesin-dockerin interactions for multi-protein assemblies

the Associate Laboratory for Animal and Veterinary Sciences (AL4AnimalS) grant LA/P/0059/2020. LA/P/0140/2020 of the Associate Laboratory Institute for Health and Bioeconomy - i4HB. National Institutes of Health R01-GM129325 and the Office of Cyber Infrastructure and Computational Biology, National Institute of Allergy and Infectious Diseases. Publisher Copyright: © 2022 The Author(s)The cellulosome is an elaborate multi-enzyme structure secreted by many anaerobic microorganisms for the efficient degradation of lignocellulosic substrates. It is composed of multiple catalytic and non-catalytic components that are assembled through high-affinity protein-protein interactions between the enzyme-borne dockerin (Doc) modules and the repeated cohesin (Coh) modules present in primary scaffoldins. In some cellulosomes, primary scaffoldins can interact with adaptor and cell-anchoring scaffoldins to create structures of increasing complexity. The cellulosomal system of the ruminal bacterium, Ruminococcus flavefaciens, is one of the most intricate described to date. An unprecedent number of different Doc specificities results in an elaborate architecture, assembled exclusively through single-binding-mode type-III Coh-Doc interactions. However, a set of type-III Docs exhibits certain features associated with the classic dual-binding mode Coh-Doc interaction. Here, the structure of the adaptor scaffoldin-borne ScaH Doc in complex with the Coh from anchoring scaffoldin ScaE is described. This complex, unlike previously described type-III interactions in R. flavefaciens, was found to interact in a dual-binding mode. The key residues determining Coh recognition were also identified. This information was used to perform structure-informed protein engineering to change the electrostatic profile of the binding surface and to improve the affinity between the two modules. The results show that the nature of the residues in the ligand-binding surface plays a major role in Coh recognition and that Coh-Doc affinity can be manipulated through rational design, a key feature for the creation of designer cellulosomes or other affinity-based technologies using tailored Coh-Doc interactions.publishersversionepub_ahead_of_prin

Mesenchymal stem cells from patients with chronic myeloid leukemia do not express BCR-ABL and have absence of chimerism after allogeneic bone marrow transplant

Bone marrow is a heterogeneous cell population which includes hematopoietic and mesenchymal progenitor cells. Dysregulated hematopoiesis occurs in chronic myelogenous leukemia (CML), being caused at least in part by abnormalities in the hematopoietic progenitors. However, the role of mesenchymal stem cells (MSCs) in CML has not been well characterized. The objectives of the present study were to observe the biological characteristics of MSCs from CML patients and to determine if MSCs originate in part from donors in CML patients after bone marrow transplantation (BMT). We analyzed MSCs from 5 untreated patients and from 3 CML patients after sex-mismatched allogeneic BMT. Flow cytometry analysis revealed the typical MSC phenotype and in vitro assays showed ability to differentiate into adipocytes and osteoblasts. Moreover, although some RT-PCR data were contradictory, combined fluorescence in situ hybridization analysis showed that MSCs from CML patients do not express the bcr-abl gene. Regarding MSCs of donor origin, although it is possible to detect Y target sequence by nested PCR, the low frequency (0.14 and 0.34%) of XY cells in 2 MSC CML patients by fluorescence in situ hybridization analysis suggests the presence of contaminant hematopoietic cells and the absence of host-derived MSCs in CML patients. Therefore, we conclude that MSCs from CML patients express the typical MSC phenotype, can differentiate into osteogenic and adipogenic lineages and do not express the bcr-abl gene. MSCs cannot be found in recipients 12 to 20 months after BMT. The influence of MSCs on the dysregulation of hematopoiesis in CML patients deserves further investigation

Recent progress with hot carrier solar cells

Hot carrier solar cells offer one of the most promising options for high performance “third generation” photovoltaic devices. For successful operation, these need to be thin, strongly absorbing, radioactively efficient devices in a simple 2-terminal configuration. Nonetheless, they offer potential performance close to the maximum possible for solar conversion, equivalent to a multi-cell stack of six or more tandem cells possibly without some of the limitations, such as spectral sensitivity. However, hot carrier cells offer some quite fundamental challenges in implementation that our team is addressing in an internationally collaborative effort

Corneal Biomechanics in Ectatic Diseases: Refractive Surgery Implications.

BACKGROUND: Ectasia development occurs due to a chronic corneal biomechanical decompensation or weakness, resulting in stromal thinning and corneal protrusion. This leads to corneal steepening, increase in astigmatism, and irregularity. In corneal refractive surgery, the detection of mild forms of ectasia pre-operatively is essential to avoid post-operative progressive ectasia, which also depends on the impact of the procedure on the cornea. METHOD: The advent of 3D tomography is proven as a significant advancement to further characterize corneal shape beyond front surface topography, which is still relevant. While screening tests for ectasia had been limited to corneal shape (geometry) assessment, clinical biomechanical assessment has been possible since the introduction of the Ocular Response Analyzer (Reichert Ophthalmic Instruments, Buffalo, USA) in 2005 and the Corvis ST (Oculus Optikgerate GmbH, Wetzlar, Germany) in 2010. Direct clinical biomechanical evaluation is recognized as paramount, especially in detection of mild ectatic cases and characterization of the susceptibility for ectasia progression for any cornea. CONCLUSIONS: The purpose of this review is to describe the current state of clinical evaluation of corneal biomechanics, focusing on the most recent advances of commercially available instruments and also on future developments, such as Brillouin microscopy.(undefined)info:eu-repo/semantics/publishedVersio

Predicting stroke through genetic risk functions: the CHARGE Risk Score Project.

BACKGROUND AND PURPOSE: Beyond the Framingham Stroke Risk Score, prediction of future stroke may improve with a genetic risk score (GRS) based on single-nucleotide polymorphisms associated with stroke and its risk factors. METHODS: The study includes 4 population-based cohorts with 2047 first incident strokes from 22,720 initially stroke-free European origin participants aged ≥55 years, who were followed for up to 20 years. GRSs were constructed with 324 single-nucleotide polymorphisms implicated in stroke and 9 risk factors. The association of the GRS to first incident stroke was tested using Cox regression; the GRS predictive properties were assessed with area under the curve statistics comparing the GRS with age and sex, Framingham Stroke Risk Score models, and reclassification statistics. These analyses were performed per cohort and in a meta-analysis of pooled data. Replication was sought in a case-control study of ischemic stroke. RESULTS: In the meta-analysis, adding the GRS to the Framingham Stroke Risk Score, age and sex model resulted in a significant improvement in discrimination (all stroke: Δjoint area under the curve=0.016, P=2.3×10(-6); ischemic stroke: Δjoint area under the curve=0.021, P=3.7×10(-7)), although the overall area under the curve remained low. In all the studies, there was a highly significantly improved net reclassification index (P<10(-4)). CONCLUSIONS: The single-nucleotide polymorphisms associated with stroke and its risk factors result only in a small improvement in prediction of future stroke compared with the classical epidemiological risk factors for stroke