Ixodid fauna and zoonotic agents in ticks from dogs: first report of Rickettsia rickettsii in Rhipicephalus sanguineus in the state of Mato Grosso do Sul, mid-western Brazil

Ticks from 148 dogs from the urban area of the municipality of Campo Grande, state of Mato Grosso do Sul, Brazil, were collected, classified and analyzed using polymerase chain reaction (PCR) for the identification of Rickettsia spp., Trypanosoma cruzi and Leishmania spp. A total of 2015 ticks were collected. The species Rhipicephalus sanguineus (98.9 %) and Amblyomma cajennense (1.1 %) were identified. Molecular analysis revealed that no tick samples were infected by T. cruzi. Regarding Leishmania spp., tick samples from 36 dogs spread across all regions of the municipality were positive for L. chagasi. One tick sample was positive for Rickettsia spp. (gltA gene) in the PCR reaction. This sample was submitted to further PCR based on the ompA gene and the amplicon was sequenced. Identity of 100 % was found with homologous sequences of R. rickettsii available in GenBank. This paper is the first to report the natural infection of R. sanguineus by R. rickettsii in the municipality of Campo Grande, state of Mato Grosso do Sul, mid-western Brazil.     

Premature development of ligandin (GSH transferase B) in mice with an inherited defect in endoplasmic reticulum-golgi structure and function

Radiation-induced albino mouse mutations have deficient microsomal enzyme activities and structurally abnormal endoplasmic reticulum-Golgi membranes in liver and kidney. Ligandin (GSH transferase B) is essential for nonoxidative detoxification. Cytochrome P-450, which is essential for oxidative detoxification, is virtually absent in mutant homozygous mice. The catalytic activity of ligandin in liver, kidney and small intestinal mucosa was double that of heterozygous littermates and newborn controls and was equivalent to enzyme activity in control adult mice. Early enzyme maturation in homozygous mutants probably results from accumulation of substrates which are normally metabolized by the cytochrome P-450 oxidative system.     

Ultrastructural analysis of chick embryo blastoderms explanted in vitro in absence of endoderm. Differentiation capacity of mesoderm

A study of the structural characteristics of stage 5 chick embryo blastoderms, cultured in vitro, was carried out after previous elimination of endoderm to analyse the differentiation capacity of mesoderm. Our results show that only the precardiac mesoderm is determined at this early stage and that it is able to differentiate cardiac tissue in the absence of the endoderm. The ultrastructural characteristics of this tissue are described. However, the degree of differentiation of cardiomyoblasts does not reach the expected level of organization and myofibrillar complexity.     

Effect of Rhythmic Auditory Stimulation on Gait in Parkinsonian Patients with and without Freezing of Gait

Freezing of gait (FOG) in Parkinson''s disease (PD) rises in prevalence when the effect of medications decays. It is known that auditory rhythmic stimulation improves gait in patients without FOG (PD-FOG), but its putative effect on patients with FOG (PD+FOG) at the end of dose has not been evaluated yet. This work evaluates the effect of auditory rhythmic stimulation on PD+FOG at the end of dose. 10 PD+FOG and 9 PD-FOG patients both at the end of dose periods, and 10 healthy controls were asked to perform several walking tasks. Tasks were performed in the presence and absence of auditory sensory stimulation. All PD+FOG suffered FOG during the task. The presence of auditory rhythmic stimulation (10% above preferred walking cadence) led PD+FOG to significantly reduce FOG. Velocity and cadence were increased, and turn time reduced in all groups. We conclude that auditory stimulation at the frequency proposed may be useful to avoid freezing episodes in PD+FOG.     

Fine‐scale coexistence between Mediterranean mesocarnivores is mediated by spatial,temporal, and trophic resource partitioning

1. The partition of the ecological niche can enhance the coexistence of predators due to differences in how they exploit three main resources: food, space, and time, the latter being an axis that often remains unexplored.
2. We studied niche segregation in a Mediterranean mesocarnivore community composed by Vulpes vulpes, Genetta genetta, Meles meles, and Herpestes ichneumon, addressing simultaneously different niche axes: the temporal, trophic, and spatial axes.
3. We assessed temporal segregation between mesopredators and prey and between potential competitors, using camera trap data between 2018 and 2020 in a Mediterranean landscape in Southern Spain. We deployed camera traps in 35 stations in three sites with varying vegetation cover within Doñana National Park. We further examined the spatial overlap in activity centers and trophic preferences between potential competitors using diet information from studies performed in the study area.
4. We found an overall temporal segregation between trophic generalist species, with species showing higher temporal overlap differing in their trophic preferences and/or showing limited spatial overlap. Furthermore, we observed an overall high overlap between the activity patterns of predators and their major prey in the area (the common genet vs. small mammals and the red fox vs. European rabbit).
5. Our study suggests that coexistence of the different species that compose the mesocarnivore assemblage in Mediterranean landscapes can be facilitated by subtle differences along the three main niche axes, with temporal segregation being a most pronounced mechanism. Our findings reinforce the idea that the coexistence mechanisms underlying community structure are multidimensional.

     

Opposing effects of cyclosporin A and tyrphostin AG-1478 indicate a role for Src protein in the cellular control of mineralization

Cyclosporin A (CsA) induces osteoporosis but not through direct activation of osteoclasts. CsA also inhibits cell-mediated mineralization in marrow stromal cell culture, whereas the tyrphostin AG-1478 increases mineralization. These antagonistic effects on mineralization were used to discern molecules that underwent phosphorylation changes in association with their opposing effects on mineralization. In parallel, quantitative changes in Src protein were followed. Multiple dexamethasone (DEX)-stimulated stromal cell cultures were grown with and without a mineralization-inhibiting dose (0.1 μM) of CsA and were harvested on different days of DEX stimulation. Immunoblots of gel-fractionated cell extracts showed that the most noticeable changes in tyrosine phosphorylated proteins (TPP) were seen on day 8 of DEX stimulation. At least 15 TPP bands, mostly smaller than 53 kDa, were more prominent in CsA-treated cultures on day 8. Under CsA, Src protein quantity decreased on day 8, but its cleavage product (52/54 kDa) was sixfold more abundant then on day 7. Day 8 was chosen to test the effect of AG-1478 on the CsA-induced TPP changes. Dimethyl sulfoxide (DMSO) alone, the solvent of AG-1478, increased mineralization in CsA-treated versus CsA-untreated cultures and slightly decreased Src and its cleavage product. AG-1478 at 5 μM, in CsA cultures increased the specific alkaline phosphatase activity threefold, with a slight change in mineralization relative to controls grown with DMSO alone. This was accompanied by decreased intensity of several TPP bands smaller than 36 kDa. In contrast, treatment with 50 μM of AG-1478 increased the intensity of TPP bands at the same molecular size range. This high AG-1478 dose decreased cell counts selecting mineralizing cells. The results indicate that increased Src protein cleavage product on day 8 by CsA is associated with mineralization inhibition, which is opposed by DMSO and 50-μM AG-1478, thus antagonizing the effect of CsA on mineralization. Direct or indirect interaction between Src and TPP, antagonistically affected by CsA and AG-1478, is likely to underlay cellular control of mineralization. Changes in p19 and p29 intensity showed association with mineralization that was reflected by a significant direct and inverse correlation, respectively, with calcium precipitation per cell. J. Cell. Biochem. 71:116–126, 1998. © 1998 Wiley-Liss, Inc.     

COVID-19 y salas de análisis del riesgo en salud pública en cuatro departamentos fronterizos de Colombia

Introduction:

Public health risk management in Colombia is led by the Instituto Nacional de Salud. In the face of the COVID-19 emergency, response actions centered on the implementation of risk analysis rooms and the strengthening of surveillance at points of entry into the country.

Objective:

To analyze the implementation and maintenance phases of the COVID-19 risk analysis rooms in four border departments of Colombia.

Materials and methods:

We conducted a qualitative study of public health risk analysis rooms for COVID-19. We reviewed the documentation and data generated from March to June, 2020, in the departments of Amazonas, Vichada, Guainía, and Putumayo. We did semi-structured interviews with key actors and analyzed the answers using the NVivo plus version 11 application in three cycles: open coding, identification of emerging categories, and modeling by analyzing the identified strengths and weaknesses.

Results:

We identified the components of the incident command structure and the relationships between the public health areas. Strengths were evidenced in the integration of the areas: the management of information in real time, the border surveillance and the capabilities of rapid response teams, while weaknesses appeared in planning, community surveillance, and risk communication processes.

Conclusions:

Risk analysis rooms constitute a joint effort at the national and local levels which has promoted the articulated participation of all actors in the analysis of information and the optimization of an organized response during the COVID-19 pandemic.     

Disruption of ER‐mitochondria tethering and signalling in C9orf72‐associated amyotrophic lateral sclerosis and frontotemporal dementia

Hexanucleotide repeat expansions in C9orf72 are the most common cause of familial amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). The mechanisms by which the expansions cause disease are not properly understood but a favoured route involves its translation into dipeptide repeat (DPR) polypeptides, some of which are neurotoxic. However, the precise targets for mutant C9orf72 and DPR toxicity are not fully clear, and damage to several neuronal functions has been described. Many of these functions are regulated by signalling between the endoplasmic reticulum (ER) and mitochondria. ER‐mitochondria signalling requires close physical contacts between the two organelles that are mediated by the VAPB‐PTPIP51 ‘tethering’ proteins. Here, we show that ER‐mitochondria signalling and the VAPB‐PTPIP51 tethers are disrupted in neurons derived from induced pluripotent stem (iPS) cells from patients carrying ALS/FTD pathogenic C9orf72 expansions and in affected neurons in mutant C9orf72 transgenic mice. In these mice, disruption of the VAPB‐PTPIP51 tethers occurs prior to disease onset suggesting that it contributes to the pathogenic process. We also show that neurotoxic DPRs disrupt the VAPB‐PTPIP51 interaction and ER‐mitochondria contacts and that this may involve activation of glycogen synthase kinases‐3β (GSK3β), a known negative regulator of VAPB‐PTPIP51 binding. Finally, we show that these DPRs disrupt delivery of Ca²⁺ from ER stores to mitochondria, which is a primary function of the VAPB‐PTPIP51 tethers. This delivery regulates a number of key neuronal functions that are damaged in ALS/FTD including bioenergetics, autophagy and synaptic function. Our findings reveal a new molecular target for mutant C9orf72‐mediated toxicity.