Chemical signals have an important role in the survival of many animals and are essential for the exploration of the resources available in their habitat. All phytophagous insects, including ...dipterans, use diverse chemical compounds released by plants as olfactory signals to locate their hosts. Spotted wing drosophila, Drosophila suzukii (Matsumura) (Diptera: Drosophilidae), is a generalist fly that uses numerous plants as hosts. In this study, we evaluated the attractiveness of extracts from six plants commonly used as ornamental and medicinal plants in the southern region of Mexico. When the flies were exposed to Piper auritum Kunth (Piperaceae) extract, we observed a stimulating‐attracting effect, especially on females, whereas the other five extracts showed no significant differences from their respective controls. In addition, gas chromatography coupled with mass spectrometry analysis of the P. auritum extract revealed 11 compounds, where safrole and methyl eugenol (ME) showed the highest concentrations of all the compounds found. ME has been shown to attract flies, mainly males of the genus Bactrocera. In this case, we found a stronger effect on female D. suzukii, indicating a potential effect of ME as a kairomone that mainly stimulates the attraction behavior of females.
The attraction effect of extracts of six plant species was evaluated, where Piper auritum (Piperaceae) showed a stimulant–attractant effect on Drosophila suzukii (Diptera: Drosophilidae) adults. The results show evidence of a potential effect of methyl eugenol (ME) as a kairomone that mainly stimulates the attraction of females of this species. ME could potentially be used in monitoring and control programs of this important pest.
Long INterspersed Element class 1 (LINE‐1) elements are a type of abundant retrotransposons active in mammalian genomes. An average human genome contains ~100 retrotransposition‐competent LINE‐1s, ...whose activity is influenced by the combined action of cellular repressors and activators. TREX1, SAMHD1 and ADAR1 are known LINE‐1 repressors and when mutated cause the autoinflammatory disorder Aicardi‐Goutières syndrome (AGS). Mutations in RNase H2 are the most common cause of AGS, and its activity was proposed to similarly control LINE‐1 retrotransposition. It has therefore been suggested that increased LINE‐1 activity may be the cause of aberrant innate immune activation in AGS. Here, we establish that, contrary to expectations, RNase H2 is required for efficient LINE‐1 retrotransposition. As RNase H1 overexpression partially rescues the defect in RNase H2 null cells, we propose a model in which RNase H2 degrades the LINE‐1 RNA after reverse transcription, allowing retrotransposition to be completed. This also explains how LINE‐1 elements can retrotranspose efficiently without their own RNase H activity. Our findings appear to be at odds with LINE‐1‐derived nucleic acids driving autoinflammation in AGS.
Synopsis
Several mechanisms exist to restrict LINE‐1 retrotransposition, some of which involve TREX1, SAMHD1 or ADAR1, proteins mutated in Aicardi‐Goutières syndrome (AGS), a type I interferonopathy. Mutations in RNase H2 also cause AGS. However, RNase H2 activity promotes rather than restricts LINE‐1 mobilisation.
Efficient LINE‐1 retrotransposition requires cellular RNase H2 activity.
Mobilization of vertebrate retrotransposons without an RNase H domain is severely compromised in RNASEH2A knockout cells, whereas those with their own RNase H activity are not affected.
Increased cellular RNase H activity against RNA:DNA hybrids by overexpression allows increased LINE‐1 retrotransposition.
Knockout cells complemented with RNASEH2A carrying disease mutations have impaired LINE‐1 retrotransposition.
RNase H2 likely acts on the LINE‐1 RNA:cDNA hybrid, allowing second strand synthesis and productive retrotransposition to occur.
In contrast to other Aicardi‐Goutières associated proteins that act to restrict LINE‐1 retrotranspostion, RNase H2 activity facilitates LINE‐1 mobilisation.
Vegetation type and seasonality promote changes in the species composition and abundance of parasite hosts. However, it is poorly known how these variables affect host–parasite interaction networks. ...This information is important to understand the dynamics of parasite–host relationships according to biotic and abiotic changes. We compared the specialization of host–bat fly interaction networks, as well as bat fly and host species composition between upland dry forest and riparian forest and between dry and rainy seasons in a tropical dry forest in Jalisco, Mexico. Bat flies were surveyed by direct collection from bats. Our results showed that host–bat fly interaction networks were more specialized in upland dry forest compared to riparian forest. Bat fly species composition was different between the dry and rainy seasons, while host species composition was different between upland dry forest and riparian forest. The higher specialization in upland dry forest could be related to the differences in bat host species composition and their respective roosting habits. Variation in the composition of bat fly species between dry and rainy seasons coincides with the seasonal shifts in their species richness. Our study confirms the high specialization of host–bat fly interactions and shows the importance of biotic and abiotic factors to understand the dynamics of parasite–host interactions.
Mosquitoes (Diptera: Culicidae) are considered the group of insects that most impacts human health. Land use change, conversion of conserved sites into agricultural environments, urbanization, ...defaunation, and introduction of domestic animals can affect mosquito diversity positively or negatively, increasing the risk of transmission of zoonotic diseases. Here, we describe the diversity of adult mosquitoes in two environments (deciduous forest and anthropized zone) over 2 yr (2014–2016), using eight CDC traps at each site in three climatic seasons (rainy, cold, and dry). We captured 795 individuals belonging to 22 species. We constructed rank-abundance curves to determine spatial and temporal changes in the mosquito communities. We measured alpha diversity using the Shannon index (H′), Shannon exponential (eH) and Simpson dominance (Ds), and beta diversity using Jaccard's coefficient of similarity (Ij). The most abundant species were Culex quinquefasciatus (40.5%), Culex coronator (18.3%), and Anopheles pseudopunctipennis (12.4%). The highest mosquito diversity was in the deciduous forest during the rainy season. Beta diversity analysis showed that species overlap varied among climatic seasons, with the sites sharing 65% species during the rainy season, but only 33% of species during the dry season. We found differences in the diversity of mosquitoes at the two sites, and the mosquito assemblage of the anthropized zone was significantly different from that of the deciduous forest.
Subprojective Nakano spaces Ruiz, César; Sánchez, Víctor M.
Journal of mathematical analysis and applications,
02/2018, Letnik:
458, Številka:
1
Journal Article
Recenzirano
Odprti dostop
A Banach space X is subprojective if every infinite-dimensional subspace of X has a subspace which is complemented in X. We prove that separable Nakano sequence spaces ℓ(pn) are subprojective. ...Subprojectivity is also characterized in separable Nakano function spaces Lp(⋅)(0,1) and Lp(⋅)(0,∞).
Weak compactness in variable exponent spaces Hernández, Francisco L.; Ruiz, César; Sanchiz, Mauro
Journal of functional analysis,
09/2021, Letnik:
281, Številka:
6
Journal Article
Recenzirano
Odprti dostop
This paper shows necessary and sufficient conditions on subsets of variable exponent spaces Lp(⋅)(Ω) in order to be weakly compact. Useful criteria are given extending Andô results for Orlicz spaces. ...As application, we prove that all separable variable exponent spaces are weakly Banach-Saks. Also, L-weakly compact and weakly compact inclusions between variable exponent spaces are studied.
Mining in Colombia affects 488,672 ha (298,391 in coal mining and 190,281 in gold mining). However, Colombia has insufficient studies on mining and its repercussions, which limits estimates of mining ...impacts on ecosystems and the human population. Due to the rise of mining activities in Colombia, the negative impacts generated by coal and Hg will also continue to increase. This review analyzes national information levels on coal and Hg in island/coastal/marine as well as freshwater ecosystems and human groups using fishery resources as a framework. This is because fish are the main source of animal protein in marine coastal-island and mainland communities. Here, 15 of 32 Colombian departments have records on total mercury (THg) in water, sediments, fish, and human communities. Around 205 ton/year of mercury is discharged into the ecosystem. In human hair for example (15.3 to 50.15 μg/g), mercury exceeds the international maximum levels allowed (ILA) and the national standard (5.0 μg/g). Mercury levels in freshwater fish show 3.3 μg/g of THg and levels in marine and coastal-island fish are 1.2 μg/g THg exceeding the ILA (0.5 μg/g) standard for fish that will be consumed. Carnivorous species have a THg between 0.04 and 2.55 μg/g suggesting bioaccumulation and magnification of heavy metals. These findings were then compared with available international information.
Parkinson’s disease (PD) is the second most common neurodegenerative disease globally. Current drugs only alleviate symptoms without halting disease progression, making rodent models essential for ...researching new therapies and understanding the disease better. However, selecting the right model is challenging due to the numerous models and protocols available. Key factors in model selection include construct, face, and predictive validity. Construct validity ensures the model replicates pathological changes seen in human PD, focusing on dopaminergic neurodegeneration and a-synuclein aggregation. Face validity ensures the model’s symptoms mirror those in humans, primarily reproducing motor and non-motor symptoms. Predictive validity assesses if treatment responses in animals will reflect those in humans, typically involving classical pharmacotherapies and surgical procedures. This review highlights the primary characteristics of PD and how these characteristics are validated experimentally according to the three criteria. Additionally, it serves as a valuable tool for researchers in selecting the most appropriate animal model based on established validation criteria.
Homoscleromorpha is a recently recognized class within the phylum Porifera. While molecular analyses support monophyly of Homoscleromorpha, morphological data are largely lacking. Here, we ...investigate and comparatively analyze the detailed morphology of kinetids (flagellar apparatus) in choanocytes of ten Oscarella species. The kinetid is known to be a phylogenetically important trait that can possibly reflect relationships of sponges at the level of orders. We also conduct a phylogenetic analysis based on previously published sequences. We found the family Oscarellidae is subdivided into two large groups, and choanocyte kinetids structure strongly supports this division. The first group includes Oscarella lobularis, O. tuberculata, O. bergenensis, O. viridis, O. rubra, O. malakhovi, O. microlobata, O. carmela, O. filipoi, and O. zoranja. These species possess nuclei located in a basal position without any connection to the kinetosome. The second group includes O. balibaloi, O. nicolae, O. kamchatkensis, O. pearsei, O. imperialis, and Pseudocorticium jarrei, whose nuclei are connected with the kinetosome. In addition, this second group also shares mesohylar spherulous cells harboring paracrystalline inclusions. The choanocyte kinetid structure seems to be an essential phylogenetic and diagnostic morphological trait, and we propose to include it in future species descriptions. Our results imply assignation of the second group to the genus Pseudocorticium. This taxonomic suggestion, however, needs additional data on the remaining Oscarella species.
Structure of the choanocyte kinetids in oscarellid sponges (Porifera, Homoscleromorpha) reveals subdivision of the family Oscarellidae into two large groups. Species of the first group possess nuclei located in a basal position without any connection to the kinetosome. The nuclei of the second group are connected with the kinetosome. This group also shares mesohylar spherulous cells harboring paracrystalline inclusions. Genetic analysis confirms such subdivision. The kinetid structure is therefore an essential morphotrait for systematics of Homoscleromorpha.
Changes in the specialization of parasite-host interactions will be influenced by variations in host species composition. We evaluated this hypothesis by comparing the composition of bats and bat ...flies within a roost cave over one annual. Five bat and five bat fly species occupied the cave over the course of the study. Bat species composition was 40% different in the rainy season compared with the dry-cold and dry-warm seasons. Despite the incorporation of three new bat species into the cave during the rainy season, bat fly species composition was not affected by seasonality, since the bats that arrived in the rainy season only contributed one new bat fly species at a low prevalence. Bat-bat fly ecological networks were less specialized in the rainy season compared with the dry-cold and dry-warm seasons because of the increase of host overlap among bat fly species during this season. This study suggests that seasonality promote: (1) differences in host species composition, and (2) a reduction in the specialization of host-parasite ecological networks.
PDF
