MAIN CONCLUSION : RCI2 / PMP3 s participate in abiotic stress responses and impact the expression of other genes. Their multifunctionality is determined by differential expression and by distinct ...activities of their structurally different proteins. In plants, RCI2/PMP3 genes, which encode small membrane proteins of the PMP3 family, are closely associated with abiotic stress responses. Their involvement in mediating stress tolerance is supported by genetic evidence and overexpression studies. RCI2/PMP3s occur as multigenes in plant genomes and their encoded proteins belong to distinct and conserved structural groups. In addition, different isoforms appear to be targeted to the plasma membrane or to distinct endomembrane compartments in cells. Several studies have revealed that RCI2/PMP3 proteins participate in cell ion homeostasis, and in regulation of membrane stability and polarization. They also appear to potentiate plant transcriptional responses to abiotic stresses. However, their mechanisms of action remain unknown. This paper reviews the current knowledge of the multiple roles of plant RCI2/PMP3 genes resulting from their differential expression under normal and stress conditions. The structural diversity of RCI2/PMP3 proteins is analyzed and evidence supporting their functional specialization and possible activity mechanisms is examined. Finally, strategies are discussed for exploiting new and established technologies to overcome the difficulties posed by the multigene status of RCI2s and the integral membrane character of their proteins, enabling the probing of their individual functions and collective significance.
Habitat loss is the main driver of the current biodiversity crisis, a landscape-scale process that affects the survival of spatially-structured populations. Although it is well-established that ...species responses to habitat loss can be abrupt, the existence of a biodiversity threshold is still the cause of much controversy in the literature and would require that most species respond similarly to the loss of native vegetation. Here we test the existence of a biodiversity threshold, i.e. an abrupt decline in species richness, with habitat loss. We draw on a spatially-replicated dataset on Atlantic forest small mammals, consisting of 16 sampling sites divided between forests and matrix habitats in each of five 3600-ha landscapes (varying from 5% to 45% forest cover), and on an a priori classification of species into habitat requirement categories (forest specialists, habitat generalists and open-area specialists). Forest specialists declined abruptly below 30% of forest cover, and spillover to the matrix occurred only in more forested landscapes. Generalists responded positively to landscape heterogeneity, peaking at intermediary levels of forest cover. Open area specialists dominated the matrix and did not spillover to forests. As a result of these distinct responses, we observed a biodiversity threshold for the small mammal community below 30% forest cover, and a peak in species richness just above this threshold. Our results highlight that cross habitat spillover may be asymmetrical and contingent on landscape context, occurring mainly from forests to the matrix and only in more forested landscapes. Moreover, they indicate the potential for biodiversity thresholds in human-modified landscapes, and the importance of landscape heterogeneity to biodiversity. Since forest loss affected not only the conservation value of forest patches, but also the potential for biodiversity-mediated services in anthropogenic habitats, our work indicates the importance of proactive measures to avoid human-modified landscapes to cross this threshold.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
CONTEXT: Loss of natural habitat can isolate pollinator populations and negatively affect sexual reproduction of animal-pollinated plants. OBJECTIVE: We evaluated how the loss of natural forest ...affects pollinator diversity in the understory of the Atlantic Rainforest in Northeastern Brazil. METHODS: We focused on bees, the main group of pollinators for angiosperms. We assessed how changes in forest cover at regional (36 km²) and local (0.36 km²) scales affect bee richness and abundance. RESULTS: We sampled 492 bees from 59 species, of which 58 % were above ground nesting species and 73 % exhibited some level of sociality. Our results show that the loss of forest had negative effects on understory bee abundance, which was particularly accentuated for species that nest above ground. However, for social bees the effect of changes in forest cover at a local scale depended on regional forest cover, negative effects being only detected when landscapes had at least 35 % of forest. For bee richness, the null model was among the best models bringing considerable uncertainty about landscape effects on bee richness. CONCLUSIONS: These findings suggest that management strategies and conservation practices must integrate proper actions that consider both local and regional scales. For existing fragmented landscapes, it is important to increase forest availability at the regional scale, while also maintaining high environmental heterogeneity at the local scale. We believe that with proper landscape planning this multiscalar approach can be not only more effective, but also easier to implement.
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EMUNI, GEOZS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UL, UM, UPUK, VKSCE, ZAGLJ
Polycomb and Trithorax group proteins encode the epigenetic memory of cellular positional identity by establishing inheritable domains of repressive and active chromatin within the Hox clusters. Here ...we demonstrate that the CCCTC-binding factor (CTCF) functions to insulate these adjacent yet antagonistic chromatin domains during embryonic stem cell differentiation into cervical motor neurons. Deletion of CTCF binding sites within the Hox clusters results in the expansion of active chromatin into the repressive domain. CTCF functions as an insulator by organizing Hox clusters into spatially disjoint domains. Ablation of CTCF binding disrupts topological boundaries such that caudal Hox genes leave the repressed domain and become subject to transcriptional activation. Hence, CTCF is required to insulate facultative heterochromatin from impinging euchromatin to produce discrete positional identities.
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BFBNIB, NMLJ, NUK, PNG, SAZU, UL, UM, UPUK
Extinction thresholds have been predicted to be critical values of habitat loss in which an abrupt reduction in populations occurs through the interaction between reduced habitat and increased ...isolation in the landscape. In communities, extinction thresholds are referred to as 'biodiversity thresholds'. The biodiversity threshold values documented so far occur between 30% and 50% of habitat cover in landscapes. However, the assessment of biodiversity thresholds has mainly focused on vertebrate and plant communities. Here, we evaluated the occurrence of biodiversity thresholds in dung beetle communities by sampling ten 3,600 ha Atlantic Forest landscapes with forest cover ranging from 5% to 55%. We analysed the response patterns (abundance, gamma and mean alpha diversity) of community subgroups with different levels of forest dependency (forest species, generalist species, and open-area species) using model selection, comparing null, linear, bell-shaped and logistic models. The response of the community of forest species equally fits both linear and logistic models predicting a biodiversity threshold at 25% forest cover. Generalist species showed peak abundance at 20% forest cover although this result reflects a very poor generalist assembly. Open-area specialists did not respond to the amount of forest. The two most plausible models for forest species suggest two different biodiversity management options. Since the biodiversity threshold model represents a more dramatic scenario for the loss of biodiversity in Atlantic forest landscapes, we suggest, based on precautionary principle, that our results should strength guidelines that consider minimum values of forest cover in management strategies to avoid abrupt biodiversity loss and impacts on ecosystem services.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The present work describes the optimization and validation of an analytical method for the determination of six antipsychotic drugs (chlorpromazine, levomepromazine, cyamemazine, clozapine, ...haloperidol, and quetiapine) in oral fluid samples after solvent extraction from dried saliva spots, by gas chromatography coupled to tandem mass spectrometry. The method was fully validated, and the included parameters were selectivity, linearity, limits of quantification, precision and accuracy, stability, and recovery. The method was linear for all compounds from 10 to 400 ng/mL, except for haloperidol (5–100 ng/mL), presenting coefficients of determination higher than 0.99. Inter- and intra-day precision and accuracy were in conformity with the criteria usually seen in bioanalytical method validation; i.e., coefficients of variation were lower than 15% and an accuracy of 15% or better for all studied drugs. The recoveries obtained with this miniaturized technique ranged from 63 to 97%. The herein described method is the first to be reported using the dried saliva spots approach for the analysis of these antypshychotic drugs, proving great sensitivity apart from its simple and fast procedure. The method was considered a good alternative to the conventional techniques to be applied in clinical and toxicological analyses, even more taking into account the extremely low sample volume used (50 μL).
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DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NUK, OBVAL, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Background
Just a few studies to date have focused on headaches, quality of life, and academic performance in children.
Objective
Determine the effect of headaches on the life of schoolchildren and ...the association between headaches and academic performance.
Methods
We conducted a cross‐sectional study. One hundred and ninety‐five students from an elementary school were randomly selected out of 355 students aged from 10 to 15 years old. Semi‐structured interview, the Pediatric Quality of Life Inventory Version 4.0, the Children's Depression Inventory, and the State‐Trait Anxiety Inventory were used. The variables relating to academic performance were obtained by consulting the academic records.
Results
Prevalence of headaches: headache: 97.3% (179/184); migraine: 51% (94/184); tension‐type headache: 33% (61/184); primary stabbing headache: 7.6% (14/184); unclassified headaches: 5.4% (10/184). Migraine (relative risk: 3.11; 95% confidence interval: 1.54‐6.30) and more severe headaches (relative risk: 7.93; 95% confidence interval: 2.65‐23.7) were associated with lower quality of life (P < .01; multivariate logistic regression). More severe headaches were associated with lower grades in school (P < .01; multiple linear regression). Variables relating to headaches were not associated with “failing the school year” (P > .05; chi‐square test and Fisher's exact test).
Conclusion
Headaches were found to be associated with lower quality of life and poor academic performance.
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Objective
To review the epidemiology, the differential diagnosis, and the clinical and laboratory factors associated with the care management of headaches in patients with systemic lupus ...erythematosus (SLE).
Background
SLE is a chronic autoimmune disease and in 12%–95% of patients, the nervous system is involved. Headache is a frequently reported, although nonspecific, symptom that may potentially represent serious underlying diagnoses. Primary headaches may also occur in these patients, thereby causing a negative and significant impact on their quality of life.
Methods
This is a narrative review. A literature review was conducted on the PubMed platform using the following terms: (1) headache and (2) lupus. All articles considered relevant were included. No limitations were imposed for the publication date.
Results
Headache is a frequent symptom in patients with SLE. Although its prevalence is similar to the general population, headaches nonetheless tend to have a greater negative impact on these patients. Patients with SLE are more likely to experience headache due to vascular diseases such as cerebral venous sinus thrombosis, stroke, reversible cerebral vasoconstriction syndrome, posterior reversible encephalopathy syndrome, and vasculitis. Aseptic meningitis, neuroinfections, intracranial neoplasms, and intracranial hypertension or hypotension may also be a cause of headache in these patients. Although used in disease activity scores, the concept of lupus headache is controversial.
Conclusions
Headache is a frequent symptom in patients with SLE. An appropriate approach enables the potentially serious conditions, which are the causes of secondary headaches, to be recognized and treated, together with an appropriate diagnosis and treatment of primary headaches.
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Objective
To review data regarding the epidemiology, pathophysiology, characteristics, and management of COVID‐19–associated headache. The persistence of headache after the acute phase of COVID‐19 ...was also reviewed.
Background
Headache is a frequent symptom of COVID‐19, and understanding its management is important for health‐care professionals involved in treating the disease.
Method
This is a narrative review. A literature review was conducted in the PubMed database with the following terms: “headache” and “COVID‐19.” All articles written in English that were considered relevant were included.
Results
Half of the patients who have COVID‐19 present with headache, which occurs more frequently in younger patients; in those with previous primary headache or with previous migraine; and in those who have concomitantly presented with anosmia, ageusia, and myalgia. The headache usually begins early in the symptomatic phase, is bilateral, moderate to severe, and has a similar pattern to tension‐type headache. All studies found the migraine pattern and the tension‐type headache pattern to be frequent patterns. The possible pathophysiological mechanisms include direct viral injury, the inflammatory process, hypoxemia, coagulopathy, and endothelial involvement. Common analgesics and nonsteroidal anti‐inflammatory drugs are the most commonly used drugs for headache in the acute phase of COVID‐19. The headache may persist beyond the acute phase, and in such cases, there is an improvement over time. However, not all patients’ headaches improve. It seems to be a greater proportion of patients whose headache improves in the first 3 months after the acute phase of the disease than after this period. COVID‐19 may trigger new daily persistent headache.
Conclusions
Headache is a clinically significant symptom of COVID‐19. Although its characteristics in the acute phase of the disease are already well known, there is a need for studies on its management and persistence.
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Polycomb repressive complex 2 (PRC2) maintains gene silencing by catalyzing methylation of histone H3 at lysine 27 (H3K27me2/3) within chromatin. By designing a system whereby PRC2-mediated ...repressive domains were collapsed and then reconstructed in an inducible fashion in vivo, a two-step mechanism of H3K27me2/3 domain formation became evident. First, PRC2 is stably recruited by the actions of JARID2 and MTF2 to a limited number of spatially interacting “nucleation sites,” creating H3K27me3-forming Polycomb foci within the nucleus. Second, PRC2 is allosterically activated via its binding to H3K27me3 and rapidly spreads H3K27me2/3 both in cis and in far-cis via long-range contacts. As PRC2 proceeds further from the nucleation sites, its stability on chromatin decreases such that domains of H3K27me3 remain proximal, and those of H3K27me2 distal, to the nucleation sites. This study demonstrates the principles of de novo establishment of PRC2-mediated repressive domains across the genome.
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•PRC2 nucleation at a subset of CpG islands forms spatial clusters in the nucleus•JARID2 and MTF2 increase the stability of PRC2 at its nucleation sites•Initial PRC2 activity forms H3K27me3 foci within the nucleus•After nucleation, PRC2 spreads H3K27me2/3 in cis and in far-cis via 3D contacts
Oksuz et al. define nucleation and spreading regions for Polycomb repressive complex 2 (PRC2), demonstrating the principle of PRC2 domain formation in mammals. They elucidate the role of genome architecture in formation of these domains and identify JARID2 and MTF2 as being crucial for full recruitment of PRC2 to chromatin.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
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