mRNA translation in astrocytes controls hippocampal long-term synaptic plasticity and memory.

Activation of neuronal protein synthesis upon learning is critical for the formation of long-term memory. Here, we report that learning in the contextual fear conditioning paradigm engenders a decrease in eIF2α (eukaryotic translation initiation factor 2) phosphorylation in astrocytes in the hippocampal CA1 region, which promotes protein synthesis. Genetic reduction of eIF2α phosphorylation in hippocampal astrocytes enhanced contextual and spatial memory and lowered the threshold for the induction of long-lasting plasticity by modulating synaptic transmission. Thus, learning-induced dephosphorylation of eIF2α in astrocytes bolsters hippocampal synaptic plasticity and consolidation of long-term memories.

eIF2-dependent translation initiation: Memory consolidation and disruption in Alzheimer's disease.

Memory storage is a conserved survivability feature, present in virtually any complex species. During the last few decades, much effort has been devoted to understanding how memories are formed and which molecular switches define whether a memory should be stored for a short or a long period of time. Among these, de novo protein synthesis is known to be required for the conversion of short- to long-term memory. There are a number translational control pathways involved in synaptic plasticity and memory consolidation, including the phosphorylation of the eukaryotic initiation factor 2 alpha (eIF2α), which has emerged as a critical molecular switch for long-term memory consolidation. In this review, we discuss findings pertaining to the requirement of de novo protein synthesis to memory formation, how local dendritic and axonal translation is regulated in neurons, and how these can influence memory consolidation. We also highlight the importance of eIF2α-dependent translation initiation to synaptic plasticity and memory formation. Finally, we contextualize how aberrant phosphorylation of eIF2α contributes to Alzheimer's disease (AD) pathology and how preventing disruption of eIF2-dependent translation may be a therapeutic avenue for preventing and/or restoring memory loss in AD.

Optical Control of Translation with a Puromycin Photoswitch.

Translation is an elementary cellular process that involves a large number of factors interacting in a concerted fashion with the ribosome. Numerous natural products have emerged that interfere with the ribosomal function, such as puromycin, which mimics an aminoacyl tRNA and causes premature chain termination. Here, we introduce a photoswitchable version of puromycin that, in effect, puts translation under optical control. Our compound, termed puroswitch, features a diazocine that allows for reversible and nearly quantitative isomerization and pharmacological modulation. Its synthesis involves a new photoswitchable amino acid building block. Puroswitch shows little activity in the dark and becomes substantially more active and cytotoxic, in a graded fashion, upon irradiation with various wavelengths of visible light. In vitro translation assays confirm that puroswitch inhibits translation with a mechanism similar to that of puromycin itself. Once incorporated into nascent proteins, puroswitch reacts with standard puromycin antibodies, which allows for tracking de novo protein synthesis using western blots and immunohistochemistry. As a cell-permeable small molecule, puroswitch can be used for nascent proteome profiling in a variety of cell types, including primary mouse neurons. We envision puroswitch as a useful biochemical tool for the optical control of translation and for monitoring newly synthesized proteins in defined locations and at precise time points.

A novel receptor for platelet-activating factor and lysophosphatidylcholine in Trypanosoma cruzi.

The lipid mediators, platelet-activating factor (PAF) and lysophosphatidylcholine (LPC), play relevant pathophysiological roles in Trypanosoma cruzi infection. Several species of LPC, including C18:1 LPC, which mimics the effects of PAF, are synthesized by T. cruzi. The present study identified a receptor in T. cruzi, which was predicted to bind to PAF, and found it to be homologous to members of the progestin and adiponectin family of receptors (PAQRs). We constructed a three-dimensional model of the T. cruzi PAQR (TcPAQR) and performed molecular docking to predict the interactions of the TcPAQR model with C16:0 PAF and C18:1 LPC. We knocked out T. cruzi PAQR (TcPAQR) gene and confirmed the identity of the expressed protein through immunoblotting and immunofluorescence assays using an anti-human PAQR antibody. Wild-type and knockout (KO) parasites were also used to investigate the in vitro cell differentiation and interactions with peritoneal mouse macrophages; TcPAQR KO parasites were unable to react to C16:0 PAF or C18:1 LPC. Our data are highly suggestive that PAF and LPC act through TcPAQR in T. cruzi, triggering its cellular differentiation and ability to infect macrophages.

Impact of different numbers of milk test-day records during lactation on the reliability of estimated breeding values.

The objective of this study was to evaluate the impact of the reduction in the number of test-day records per lactation on genetic parameters of test-day milk yield (TDMY) and the reliability of estimated breeding values for 305-day milk yield in Holstein cattle. Estimates of genetic parameters and breeding values were performed using the animal model of random regression and adjustment of the Legendre polynomial (fourth order). When comparing sires with the same number of daughters, greater reliability was found in the subpopulations with the highest number of milk test-day records per lactation per cow. It was also found that the elimination of at least one test-day record affected the reliability of estimated breeding value for 305-day milk yield in the sires, regardless of the class of number of daughters per sire. When selecting the 5% best sires and 20% best cows, the lowest order correlations were observed between the population with 10 test-day records per lactation (complete lactation) and the other subpopulations with incomplete lactations (4, 5, 6, 7, 8, 9 test-day records per lactation). The reduction in the number of test-day milk records per lactation interferes in the reliability of the estimated breeding value for sires and cows, negatively impacting the precision of selecting genetically superior animals.

Effect of microaerophilic treatment on swine wastewater (SWW) treatment: Engineering and microbiological aspects.

The microaerobic process on swine wastewater (SWW) treatment was investigated, evaluating its effect on organic matter hydrolysis and removal, biogas production, operational stability, and microbial community structure. UASB reactors operating under higher organic loading rates (OLRs) and lower hydraulic retention times (HRTs) than those found in the SWW treatment literature were also assessed. The microaerophilic reactor R2 presented a higher total and particulate organic matter removals and operational stability than the anaerobic reactor R1, reaching CODP removals of 79.4 ± 4.6%. In the specific methanogenic activity (SMA) tests, the microaerobic sludge (R2) showed hydrolytic and acetogenic/methanogenic activity superior to inoculum and anaerobic sludge (R1). The microbiological evaluation of R2 revealed the high presence of hydrolytic microorganisms, therefore justifying the higher hydrolytic activity found in the SMA tests and higher particulate organic matter removal found in the microaerobic reactor.

Construction and reconstruction of brain circuits: normal and pathological axon guidance.

Perception of our environment entirely depends on the close interaction between the central and peripheral nervous system. In order to communicate each other, both systems must develop in parallel and in coordination. During development, axonal projections from the CNS as well as the PNS must extend over large distances to reach their appropriate target cells. To do so, they read and follow a series of axon guidance molecules. Interestingly, while these molecules play critical roles in guiding developing axons, they have also been shown to be critical in other major neurodevelopmental processes, such as the migration of cortical progenitors. Currently, a major hurdle for brain repair after injury or neurodegeneration is the absence of axonal regeneration in the mammalian CNS. By contrasts, PNS axons can regenerate. Many hypotheses have been put forward to explain this paradox but recent studies suggest that hacking neurodevelopmental mechanisms may be the key to promote CNS regeneration. Here we provide a seminar report written by trainees attending the second Flagship school held in Alpbach, Austria in September 2018 organized by the International Society for Neurochemistry (ISN) together with the Journal of Neurochemistry (JCN). This advanced school has brought together leaders in the fields of neurodevelopment and regeneration in order to discuss major keystones and future challenges in these respective fields.

Heck reaction synthesis of anthracene and naphthalene derivatives as traps and clean chemical sources of singlet molecular oxygen in biological systems.

Studies have previously shown that anthracene and naphthalene derivatives serve as compounds for trapping and chemically generating singlet molecular oxygen [O2(1Δg)], respectively. Simple and efficient synthetic routes to anthracene and naphthalene derivatives are needed, for improved capture and release of O2(1Δg) in cellular environments. Because of this need, we have synthesized a dihydroxypropyl amide naphthlene endoperoxide as a O2(1Δg) donor, as well as five anthracene derivatives as O2(1Δg) acceptor. The anthracene derivatives bear dihydroxypropyl amide, ester, and sulfonate ion end groups connected to 9,10-positions by way of unsaturated (vinyl) and saturated (ethyl) bridging groups. Heck reactions were found to yield these six compounds in easy-to-carry out 3-step reactions in yields of 50-76%. Preliminary results point to the potential of the anthracene compounds to serve as O2(1Δg) acceptors and would be amenable for future use in biological systems to expand the understanding of O2(1Δg) in biochemistry.

The Xavante Longitudinal Health Study in Brazil: Objectives, design, and key results.

OBJECTIVE: The Xavante Longitudinal Health Study was developed to permit granular tracking of contemporary health challenges faced by indigenous communities in Brazil, taking into consideration ongoing historical processes that may be associated with increases in child undernutrition, adult obesity, and cardiovascular disease risks. METHODS: This was an open-cohort study with six semiannual data collection waves from 2009 to 2012. The study was undertaken in two Xavante villages, Pimentel Barbosa and Etênhiritipá, State of Mato Grosso, Central Brazil. No sampling technique was used. Data collection placed emphasis on growth and nutrition of children under five and nutrition status, blood pressure, and blood glucose levels of adolescents and adults. RESULTS: Baseline data collection began in July/August 2009 with a population census (656 individuals). Between the first and final waves, the study population increased by 17%. At baseline, stunting and wasting was elevated for most age groups <10 years. Overweight, obesity, and increased risk of metabolic complications were expressive among individuals >17 years, disproportionately affecting females. Anemia was elevated in most age groups, especially among females. Mean systolic and diastolic blood pressure was moderate. The overall prevalence of high blood pressure was relatively low. CONCLUSIONS: Our findings reveal marked health disparities relative to the Brazilian national population and a complex dietary health epidemiology involving the double burden of malnutrition, rapidly changing nutritional indicators, and elevated metabolic disease risk. The topically broad multidisciplinary focus permitted construction of the richest longitudinal data set of socio-epidemiological information for an indigenous population in Brazil.

Oral Transmission of Trypanosoma cruzi, Brazilian Amazon.

In the Brazilian Amazon, the suspected source of infection in an outbreak of acute Chagas disease involving 10 patients was Euterpe oleracea (açaí berry) juice. Patient blood and juice samples contained Trypanosoma cruzi TcIV, indicating oral transmission of the Chagas disease agent.

Ochratoxin A production by Aspergillus westerdijkiae in Italian-type salami.

The occurrence of ochratoxin A (OTA) in matured meat products can be attributed to mycotoxin coming from raw materials and/or molds that develop on the product surface during ripening. This work aimed to evaluate OTA production by Aspergillus westerdijkiae inoculated on the surface of sausages and its diffusion into the product throughout ripening, study the effect of relative humidity (RH) on the production of this mycotoxin, and investigate the presence of OTA in dry fermented sausages that naturally present intense contamination by A. westerdijkiae. Italian-type sausages were surface inoculated with A. westerdijkiae and two distinct experiments were performed. In the first, the sausages were matured in a chamber with decreasing RH (from 95 to 75%) for 35 days. In the other, the sausages were incubated under different RH (79, 85 or 95%) for 21 days. Samples were taken at the beginning of the experiments and every 7 days, subdividing into casing, outer border, and core for analyses. Sausage samples naturally spoiled by ochratoxigenic fungi were collected during sanitary inspection. Even in the presence of A. westerdijkiae mycelia, no OTA was detected for up to 7 days of sausage maturation. On the other hand, this study demonstrated that the growth of A. westerdijkiae on salami surface produces high amounts of OTA on the casing and allows its diffusion through the casing with contamination to the outer border of sausages. In the same way, it shows that under similar water activity values of substrate, RH influences the amount of OTA produced. Conversely, OTA was restricted to the casing in the naturally contaminated sausages.

Interaction of amyloid-ß (Aß) oligomers with neurexin 2α and neuroligin 1 mediates synapse damage and memory loss in mice.

Brain accumulation of the amyloid-ß protein (Aß) and synapse loss are neuropathological hallmarks of Alzheimer disease (AD). Aß oligomers (AßOs) are synaptotoxins that build up in the brains of patients and are thought to contribute to memory impairment in AD. Thus, identification of novel synaptic components that are targeted by AßOs may contribute to the elucidation of disease-relevant mechanisms. Trans-synaptic interactions between neurexins (Nrxs) and neuroligins (NLs) are essential for synapse structure, stability, and function, and reduced NL levels have been associated recently with AD. Here we investigated whether the interaction of AßOs with Nrxs or NLs mediates synapse damage and cognitive impairment in AD models. We found that AßOs interact with different isoforms of Nrx and NL, including Nrx2α and NL1. Anti-Nrx2α and anti-NL1 antibodies reduced AßO binding to hippocampal neurons and prevented AßO-induced neuronal oxidative stress and synapse loss. Anti-Nrx2α and anti-NL1 antibodies further blocked memory impairment induced by AßOs in mice. The results indicate that Nrx2α and NL1 are targets of AßOs and that prevention of this interaction reduces the deleterious impact of AßOs on synapses and cognition. Identification of Nrx2α and NL1 as synaptic components that interact with AßOs may pave the way for development of novel approaches aimed at halting synapse failure and cognitive loss in AD.

The genetic heterogeneity of hereditary transthyretin amyloidosis in a sample of the Brazilian population.

To present the genetic heterogeneity of a sample of the Brazilian population with transthyretin (TTR) mutations. This cohort study was descriptive and retrospective, and enrolled patients with peripheral neuropathy of unknown cause that were found to have a mutation in the TTR gene during the process of etiological investigation, between July 1997 to January 2016. Over the study period, 129 point mutations were identified in 448 tested patients, of whom 128 were of Brazilian origin. The TTR Val30Met mutation was identified in 116 patients (90.6%); while 7 (4.7%) patients had a pathogenic non-TTR mutation and 7 (4.7%) carried non-pathogenic mutations (4.7%). The four non-TTRMet30 pathogenic mutations were TTR Aps38Tyr; TTR Ile107Val; TTR Val71Ala; and TTR Val122Ile. In the non-pathogenic group, we only found two mutations, including TTR Gly6Ser and TTR Thr119Thr. Our study depicts a scenario of greater genetic heterogeneity among Brazilian hereditary transthyretin amyloidosis (hATTR) patients with familial amyloidotic polyneuropathy (FAP). We expect that this number will grow fast over a short period of time, due to increasing availability of genetic tests, increasing knowledge of the disease and the multivariate origin of our population.

Influence of body condition score at calving on the metabolic status and production performance of Murrah buffaloes (Bubalus bubalis) during the transition period.

OBJECTIVE: The purpose of this study was to evaluate the influence of body condition score (BCS) at calving on the metabolic status of female Murrah buffaloes in the transition period. METHODS: Thirty-seven pregnant buffaloes (multiparous) were selected and monitored during the transition period based on their body condition score and on the estimated calving date. Two groups were formed: i) buffaloes with a BCS>3.5 (n = 17); this group was classified and named 'high BCS at calving' (HBCS); and ii) buffaloes with a BCS≤3.5 (n = 20); this group was classified and named 'low BCS at calving' (LBCS). All animals were monitored during the last 30 days of pregnancy and the first 70 days post-calving and kept in the same environment and under the same feeding and management conditions. Mean values for BCS at calving were 2.98±0.9 (mean±standard error of the mean [SEM]) and 4.21±0.9 (mean±SEM) for the HBCS and LBCS groups, respectively. RESULTS: The HBCS group showed higher milk fat content (p = 0.007) and milk fat yield (p = 0.027) and a higher concentration of milk urea nitrogen (p = 0.001) than LBCS buffaloes, which in turn had a lower urine pH value (p = 0.033) than HBCS buffaloes in the pre-calving period (7.86 for HBCS vs 7.76 for LBCS). The HBCS animals had a higher concentration of erythrocytes (p = 0.001) and hematocrit (p = 0.012) post-calving and a higher hemoglobin concentration (p = 0.004) pre-calving. CONCLUSION: Buffaloes during the transition period exhibited some variations in the oxidative stress related to their metabolic status. After calving, buffaloes with a high BCS at calving and greater lipid mobilization have a more marked alteration in oxidative status, but improved production performance.

Increased Femoral Anteversion Influence Over Surgically Treated Recurrent Patellar Instability Patients.

PURPOSE: To verify the influence that increased femoral anteversion (FA) has on patients with recurrent patellar instability (RPI) treated by anteromedialization tibial tubercle osteotomy (TTO) combined with medial patellofemoral ligament reconstruction (MPFLR) and to present the midterm outcomes of these patients. METHODS: From January 2008 to August 2013, skeletally mature patients with RPI and tibial tubercle (TT)-trochlear groove (TG) ≥ 17 mm who underwent anteromedialization TTO combined with MPFLR were evaluated for J sign, patellar glide, apprehension test, increased FA, Caton index, trochlea dysplasia, TT-TG, Kujala, International Knee Documentation Committee subjective knee evaluation form, and Tegner. Increased FA was determined clinically by a difference of more than 30° between hip internal and external rotation, 70° or more of hip internal rotation, and 30° or more of femoral neck anteversion. A subgroup analysis involving increased FA was made. RESULTS: Forty-eight patients composed the study group. Mean follow-up was 41.5 ± 11.05 months. The J-sign was present in 86% before surgery and none postoperatively (P < .001). All patients had a positive apprehension test or a patellar luxation at the patellar glide test rated as grade 4 before surgery. After surgery, the mean glide was 1.29 ± 0.45 with no apprehension (P < .001). Increased FA was present in 18.7%. Caton index before surgery was 1.11 ± 0.21 and 0.99 ± 0.11 postoperatively (P = .004). Trochlea dysplasia was present in all patients. TT-TG preoperatively was 20.77 ± 2.12 mm and 11.33 ± 1.24 mm postoperatively (P < .001). Functional scores improved preoperatively to postoperatively (P < .001) with Kujala and International Knee Documentation Committee means: 59.08 to 84.37; 52.6 to 85.5, respectively. Tegner preinjury score was 5.4 and postoperatively was 5.2 (P = .01). Increased FA group had worse Kujala compared with the normal FA group and worse Kujala improvement: 77.7 and 85.89 (P = .012), and 21.7 and 26.1, respectively (P < .001). CONCLUSIONS: Increased FA in patients with RPI had a negative effect on the outcome of anteromedialization TTO combined with MPFLR. Combined anteromedialization TTO and MPFLR had good functional midterm outcomes in treating patients with RPI and TT-TG ≥ 17 mm. LEVEL OF EVIDENCE: Level III, comparative study.

Determining Cut-Off Points for the Dental Fear Survey.

OBJECTIVE: To determine a high fear cut-off point score for the Dental Fear Survey (DFS) using a single-item self-report questionnaire. METHODS: The DFS, a 20-item questionnaire assessing fear of dental treatment, was completed by 1,256 participants with a mean age of 22.3 years (SD = 5.1). Another self-report questionnaire was used to collect data on previous dental experiences. A high fear cut-off point score was determined by calculating the receiver operating characteristic (ROC) curve for the DFS. Descriptive statistics and multinomial logistic regression were calculated; a significance level of p < 0.05 was used for all tests. RESULTS: The ROC curve indicated that a DFS score ≥ 53 corresponds to a sensitivity of 88.9% and a specificity of 92.5%. Most participants (n = 895; 71.5%) reported no fear of going to the dentist. There was significant association between DFS score and fear assessed with the question "Are you fearful of going to the dentist?" (p < 0.001). CONCLUSION: A cut-off point of 53 on the DFS total score represents the best compromise between sensitivity and specificity and can be used to predict high dental fear.

Dental Fear Survey: a cross-sectional study evaluating the psychometric properties of the Brazilian Portuguese version.

OBJECTIVE: The aim of this study was to evaluate the psychometric properties of the Brazilian version of the Dental Fear Survey (DFS), previously translated to the Brazilian Portuguese language and validated. METHODS: A cross-sectional study with 1,256 undergraduates from the city of Belo Horizonte, Brazil, was carried out. The DFS and a questionnaire about previous dental experiences were self-administered. Data analysis involved descriptive statistics, principal components analysis (PCA), confirmatory factor analysis (CFA), internal consistency and test-retest reliability, and construct, discriminant, and convergent validity. RESULTS: PCA identified a three-factor structure. CFA confirmed the multidimensionality of the Brazilian version of the DFS. A modified model of the Brazilian version of the DFS fits better than the hypothesized model. The Cronbach's alpha coefficient for the total DFS scale was 0.95. CONCLUSION: The DFS demonstrated acceptable construct validity, convergent validity, and discriminant validity. These results supported the reliability and validity of the DFS among Brazilian undergraduates.