Search

The chameleon Furcifer voeltzkowi (Boettger, 1893) from northwestern Madagascar was considered to be a synonym of Furcifer rhinoceratus for many decades and was resurrected only recently based on studies of the morphology and osteology of a few male specimens, which were collected more than 100 years ago. However, basic data on this species remain unavailable, including its conservation status, life history, colouration in life, morphology of the female, genital morphology of the male, phylogenetic affinities, and genetic differentiation from F. labordi and other congeners. During a targeted expedition, we rediscovered F. voeltzkowi in its natural habitat close to its type locality, allowing us to fill some gaps of knowledge. Furcifer voeltzkowi is a sexually dimorphic species. The life colouration of males is largely green, whereas that of females is highly variable and can be extremely colourful. Both, morphology and life colouration of males and females show close similarities to F. labordi from west and southwest Madagascar, but also a number of distinct differences (e.g. a larger size of F. voeltzkowi and a smaller rostral appendage in both sexes), enabling a clear distinction of the two species in both sexes. DNA sequences of the nuclear CMOS gene and two mitochondrial markers (16S rRNA and ND4) also confirm that F. voeltzkowi is a distinct species and sister to F. labordi (pairwise differences in the 16S gene 3.5-3.6%). We estimate the distribution range (extent of occurrence) of F. voeltzkowi to comprise ca. 1.000 km2 and suggest that it qualifies as Endangered B1ab(iii) under the IUCN Red List Criteria as its populations are expected to be severely fragmented, and there is continuing decline in the extent and quality of its habitat. Similar to F. labordi, F. voeltzkowi might be an extremely short-living chameleon with a post hatching life span of only several months in the rainy season. The assumed short life might also partly explain why this splendid species got "lost" for many decades, since most roads in its habitat are not accessible in the wet season. [ABSTRACT FROM AUTHOR]

Introduction: Articles published in the literature report neurological manifestations or “complications” of SARS-CoV-2 infection and conclude that the different neurological manifestations are relatively similar, but with different frequencies. This study aimed to determine the frequency of neurological manifestations of COVID-19 and to identify which are associated with mortality. Methods: We performed a retrospective study of all patients diagnosed with SARS-CoV-2 infection by RT-PCR at Hospital 1° de Octubre, in Mexico, from the beginning of the pandemic to 22 December 2020. A total of 561 patients were identified, 370 of whom presented neurological manifestations. Results: The global mortality rate was 37.8% (140/370), increasing to 92.4% among intubated patients (135/146). Of the 370 patients included, approximately 20% of neurological symptoms (headache, neurological impairment, anosmia, ageusia) accounted for 80% of cases of neurological manifestations. Conclusions: At our hospital, 80% of the patients with neurological manifestations of COVID-19 presented headache, neurological impairment, ageusia, and/or anosmia. Neurological impairment at admission or before arriving at hospital was identified as a risk factor for mortality. Resumen: Introducción: Los artículos se han referido a manifestaciones neurológicas o «complicaciones» producidas por el SARS-CoV-2, concluyendo que las diferentes manifestaciones neurológicas han sido relativamente similares, pero con diferentes proporciones. Por ello, el objetivo de este estudio es cuantificar las manifestaciones neurológicas en COVID-19, e identificar cuál está asociada a la muerte. Material y métodos: Se realizó un estudio retrospectivo con todos los pacientes del Hospital «1.° de Octubre» infectados por COVID-19, y detectados mediante RT-PCR, desde el inicio de la pandemia hasta el 22 de diciembre de 2020, donde se obtuvieron un total de 561 casos. Resultados: La tasa de mortalidad global fue del 37,8% (140/370), mientras que para los pacientes intubados fue del 92,4% (135/146). De los 370 pacientes obtenidos, aproximadamente el 20% de las manifestaciones (cefalea, deterioro neurológico, anosmia, ageusia) ocurrieron con una frecuencia del 80% de manifestaciones neurológicas. Conclusiones: Cefalea, afección neurológica, ageusia y anosmia representaron el 80% de las manifestaciones neurológicas en el Hospital «1.° de Octubre». El deterioro neurológico al ingreso al hospital o antes de llegar fue un factor de riesgo de muerte.

The physicochemical characterization of the peptide sequences E2 (39–53) and E2 (32–59) corresponding to the structural protein E2 of the GB virus C was done by studying their interaction with model membranes. The peptides showed surface activity concentration dependent when injected beneath a buffered solution. This tendency to accumulate into the air/water interface suggested a potential ability of these peptides to interact with bilayers. For that reason, Small Unilamellar Liposomes (SUVs) of 1,2-dimyiristoyl-sn-Glycero-3-Phosphocholine (DMPC) or 1,2-dimyiristoyl-sn-Glycero-3-[Phospho-rac-(1-glycerol)] (DMPG) were chosen as a mimetic membranes. A series of fluorescence experiments based on tryptophan peptide fluorescence or with fluorescence labeled SUVs, were done to cover different aspects of peptide interaction with bilayers. Steady state fluorescence anisotropy studies with N-(7-nitro-2-1,3-benzoxadiazol-4-yl) dioleoylphosphatidylethanolamine (NBD-PE) or 1-[4-(trimethylammonium) phenyl]-6-phenyl-1,3,5-hexatriene (TMA-DPH) labeled SUVs indicated that only the long peptide was able to change the lipid microenvironment of DMPG vesicles by slightly increasing the rigidity of the bilayer both above and under the lipid main transition temperature. These results were concordant with the slight blue shift of the maximum tryptophan wavelength emission after E2 (32–53) peptide incubation with DMPG vesicles. Our data provide useful information for the design of synthetic immunopeptides that can be incorporated into a liposomal system with a potential to promote a direct delivery of the membrane-incorporated immunogen to the immunocompetent cells, thus increasing the immuno response from the host. [Copyright &y& Elsevier]

Abstract Background We report the case of a chronic stroke patient (62 months after injury) showing total absence of motor activity evoked by transcranial magnetic stimulation (TMS) of spared regions of the left motor cortex, but near-to-complete recovery of motor abilities in the affected hand. Case presentation Multimodal investigations included detailed TMS based motor mapping, motor evoked potentials (MEP), and Cortical Silent period (CSP) as well as functional magnetic resonance imaging (fMRI) of motor activity, MRI based lesion analysis and Diffusion Tensor Imaging (DTI) Tractography of corticospinal tract (CST). Anatomical analysis revealed a left hemisphere subinsular lesion interrupting the descending left CST at the level of the internal capsule. The absence of MEPs after intense TMS pulses to the ipsilesional M1, and the reversible suppression of ongoing electromyographic (EMG) activity (indexed by CSP) demonstrate a weak modulation of subcortical systems by the ipsilesional left frontal cortex, but an inability to induce efficient descending volleys from those cortical locations to right hand and forearm muscles. Functional MRI recordings under grasping and finger tapping patterns involving the affected hand showed slight signs of subcortical recruitment, as compared to the unaffected hand and hemisphere, as well as the expected cortical activations. Conclusions The potential sources of motor voluntary activity for the affected hand in absence of MEPs are discussed. We conclude that multimodal analysis may contribute to a more accurate prognosis of stroke patients.

Background Dopamine is believed to be a key neurotransmitter in the development of attention-deficit/hyperactivity disorder (ADHD). Several recent studies point to an association of the dopamine D4 receptor (DRD4) gene and this condition. More specifically, the 7 repeat variant of a variable number of tandem repeats (VNTR) polymorphism in exon III of this gene is suggested to bear a higher risk for ADHD. In the present study, we investigated the role of this polymorphism in the modulation of neurophysiological correlates of response inhibition (Go/Nogo task) in a healthy, high-functioning sample. Results Homozygous 7 repeat carriers showed a tendency for more accurate behavior in the Go/Nogo task compared to homozygous 4 repeat carriers. Moreover, 7 repeat carriers presented an increased nogo-related theta band response together with a reduced go-related beta decrease. Conclusions These data point to improved cognitive functions and prefrontal control in the 7 repeat carriers, probably due to the D4 receptor's modulatory role in prefrontal areas. The results are discussed with respect to previous behavioral data on this polymorphism and animal studies on the impact of the D4 receptor on cognitive functions.

Background: Dopamine is believed to be a key neurotransmitter in the development of attention-deficit/hyperactivity disorder (ADHD). Several recent studies point to an association of the dopamine D4 receptor (DRD4) gene and this condition. More specifically, the 7 repeat variant of a variable number of tandem repeats (VNTR) polymorphism in exon III of this gene is suggested to bear a higher risk for ADHD. In the present study, we investigated the role of this polymorphism in the modulation of neurophysiological correlates of response inhibition (Go/Nogo task) in a healthy, high-functioning sample.Results: Homozygous 7 repeat carriers showed a tendency for more accurate behavior in the Go/Nogo task compared to homozygous 4 repeat carriers. Moreover, 7 repeat carriers presented an increased nogo-related theta band response together with a reduced go-related beta decrease.Conclusions: These data point to improved cognitive functions and prefrontal control in the 7 repeat carriers, probably due to the D4 receptor's modulatory role in prefrontal areas. The results are discussed with respect to previous behavioral data on this polymorphism and animal studies on the impact of the D4 receptor on cognitive functions. [ABSTRACT FROM AUTHOR]

Merocyanine 540 (MC540) has been used as external probe to determine the interaction of the peptide sequence 125–139 corresponding to the E2 protein of Hepatitis G virus, with lipid bilayers. The probe was incorporated into large unilamellar vesicles (LUVs) or small unilamellar vesicles (SUVs) of 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC). When incorporated into bilayers, MC540 shows two absorption maxima corresponding to the monomer (570 nm) and dimer (530 nm) form of the probe. Changes in the probe microenvironment are reflected by a modification in the position and/or intensity of these maxima. Addition of increasing amounts of peptide resulted in a slight decrease of the ratio A570/A530 thus indicating a change in MC540 partition into the membrane, going from a hydrophobic to a more hydrophilic environment. This effect was concomitant with an increase in dimer formation as stated from the values of the apparent dimerization constant (Kapp) obtained. Fluorescence spectra as well as steady state anisotropy measurements were in agreement with the above results indicating that the peptide was able to relocate the probe and displacing MC540 from its initial location into the bilayer. Results with SUVs or LUVs were similar for what curvature does not seem to play any role on peptide activity. These results reflect the ability of peptide to interact with biomimetic membranes in the lipid head group region. [Copyright &y& Elsevier]

Alzheimer's disease is the most common neurodegenerative disease, and its treatment is lacking. In this work, we tested Amylovis-201, a naphthalene-derived compound, as a possible therapeutic candidate for the treatment of AD. For this purpose, we performed three experiments. In the first and third experiment, animals received a bilateral administration of streptozotocin and, starting 24 h after injection, a daily dose of Amylovis-201 (orally), for 17 days or for the whole time of the experiment respectively (28 days), after which learning and memory, as well as the number of hippocampal dentate gyrus cells, were assessed. In the second experiment, healthy animals received a single dose of Amylovis-201, 10 min or 5 h after the learning section to assess whether this substance could promote specific mechanisms involved in memory trace formation. Our data show that, administration of a single dose of Amylovis-201, 10 min after the end of training, but not at 5 h, produces a prolongation in memory duration, probably because it modulates specific mechanisms involved in memory trace consolidation. Furthermore, daily administration of Amylovis-201 to animals with bilateral intracerebroventricular injection of STZ produces a reduction in the loss of the hippocampus dentate gyrus cells and an improvement in spatial memory, probably because Amylovis-201 can interact with some of the protein kinases of the insulin signaling cascade, also involved in neural plasticity, and thereby halt or reverse some of the effects of STZ. Taking to account these results, Amylovis-201 is a good candidate for the therapeutic treatment of AD., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Memory and learning allow animals to appropriate certain properties of nature with which they can navigate in it successfully. Memory is acquired slowly and consists of two major phases, a fragile early phase (short-term memory, <4 h) and a more robust and long-lasting late one (long-term memory, >4 h). Erythropoietin (EPO) prolongs memory from 24 to 72 h when animals are trained for 5 min in a place recognition task but not when training lasted 3 min (short-term memory). It is not known whether it promotes the formation of remote memory (≥21 days). We address whether the systemic administration of EPO can convert a short-term memory into a long-term remote memory, and the neural plasticity mechanisms involved. We evaluated the effect of training duration (3 or 5 min) on the expression of endogenous EPO and its receptor to shed light on the role of EPO in coordinating mechanisms of neural plasticity using a single-trial spatial learning test. We administered EPO 10 min post-training and evaluated memory after 24 h, 96 h, 15 days, or 21 days. We also determined the effect of EPO administered 10 min after training on the expression of arc and bdnf during retrieval at 24 h and 21 days. Data show that learning induces EPO/EPOr expression increase linked to memory extent, exogenous EPO prolongs memory up to 21 days; and prefrontal cortex bdnf expression at 24 h and in the hippocampus at 21 days, whereas arc expression increases at 21 days in the hippocampus and prefrontal cortex., (© 2024 Wiley Periodicals LLC.)

Why has nature acquired such a huge lipid repertoire? Although it would be theoretically possible to make a lipid bilayer fulfilling barrier functions with only one glycerophospholipid, there are diverse and numerous different lipid species. Lipids are heterogeneously distributed across the evolutionary tree with lipidomes evolving in parallel to organismal complexity. Moreover, lipids are different between organs and tissues and even within the same cell, different organelles have characteristic lipid signatures. At the molecular level, membranes are asymmetric and laterally heterogeneous. This lipid asymmetry at different scales indicates that these molecules may play very specific molecular functions in biology. Some of these roles have been recently uncovered: lipids have been shown to be essential in processes such as hypoxia and ferroptosis or in protein sorting and trafficking but many of them remain still unknown. In this review we will discuss the importance of understanding lipid diversity in biology across scales and we will share a toolbox with some of the emerging technologies that are helping us to uncover new lipid molecular functions in cell biology and, step by step, crack the membrane lipid code., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

Suppression of a specific gene effect can be achieved by genetic as well as chemical methods. Each approach may hide unexpected drawbacks, usually in the form of side effects. In the present study, the specific inhibitor myriocin was used to block serine palmitoyltransferase (SPT), the first enzyme in the sphingolipid synthetic pathway, in CHO cells. The subsequent biophysical changes in plasma membranes were measured and compared with results obtained with a genetically modified CHO cell line containing a defective SPT (the LY-B cell line). Similar effects were observed with both approaches: sphingomyelin values were markedly decreased in myriocin-treated CHO cells and, in consequence, their membrane molecular order (measured as laurdan general polarization) and mechanical resistance (AFM-measured breakthrough force values) became lower than in the native, non-treated cells. Cells treated with myriocin reacted homeostatically to maintain membrane order, synthesizing more fully saturated and less polyunsaturated GPL than the non-treated ones, although they achieved it only partially, their plasma membranes remaining slightly more fluid and more penetrable than those from the control cells. The good agreement between results obtained with very different tools, such as genetically modified and chemically treated cells, reinforces the use of both methods and demonstrates that both are adequate for their intended use, i.e. the complete and specific inhibition of sphingolipid synthesis in CHO cells, without apparent unexpected effects., (© 2022. The Author(s).)