Distinct mechanoreceptor pezo-1 isoforms modulate food intake in the nematode Caenorhabditis elegans

Two PIEZO mechanosensitive cation channels, PIEZO1 and PIEZO2, have been identified in mammals, where they are involved in numerous sensory processes. While structurally similar, PIEZO channels are expressed in distinct tissues and exhibit unique properties. How different PIEZOs transduce force, how their transduction mechanism varies, and how their unique properties match the functional needs of the tissues they are expressed in remain all-important unanswered questions. The nematode Caenorhabditis elegans has a single PIEZO ortholog (pezo-1) predicted to have twelve isoforms. These isoforms share many transmembrane domains but differ in those that distinguish PIEZO1 and PIEZO2 in mammals. We used transcriptional and translational reporters to show that putative promoter sequences immediately upstream of the start codon of long pezo-1 isoforms predominantly drive GFP expression in mesodermally derived tissues (such as muscle and glands). In contrast, sequences upstream of shorter pezo-1 isoforms resulted in GFP expression primarily in neurons. Putative promoters upstream of different isoforms drove GFP expression in different cells of the same organs of the digestive system. The observed unique pattern of complementary expression suggests that different isoforms could possess distinct functions within these organs. We used mutant analysis to show that pharyngeal muscles and glands require long pezo-1 isoforms to respond appropriately to the presence of food. The number of pezo-1 isoforms in C. elegans, their putative differential pattern of expression, and roles in experimentally tractable processes make this an attractive system to investigate the molecular basis for functional differences between members of the PIEZO family of mechanoreceptors.

Effect of spatiotemporally changing environment on serial dependence in ensemble representations

The recent visual past has a strong impact on our current perception. Recent studies of serial dependence in perception show that low-level adaptation repels our current perception away from previous stimuli whereas post-perceptual decision attracts perceptual report toward the immediate past. In their studies, these repulsive and attractive biases were observed with different task demands perturbing ongoing sequential process. Therefore, it is unclear whether the opposite biases arise naturally in navigating complex real-life environments. Here we only manipulated the environmental statistics to characterize how serially dependent perceptual decisions unfold in spatiotemporally changing visual environments. During sequential mean orientation adjustment task on the array of Gabor patches, we found that the repulsion effect dominated only when ensemble variance increased across consecutive trials whereas the attraction effect prevailed when ensemble variance decreased or remained the same. The observed attractive bias by high-to-low-variance stimuli and repulsive bias by low-to-high-variance stimuli were reinforced by the repeated exposure to the low and the high ensemble variance, respectively. Further, this variance-dependent differential pattern of serial dependence in ensemble representation remained the same regardless of whether observers had a prior knowledge of environmental statistics or not. We used a Bayesian observer model constrained by visual adaptation to provide a unifying account of both attractive and repulsive bias in perception. Our results establish that the temporal integration and segregation of visual information is flexibly adjusted through variance adaptation.

Disentangling dimensions of animacy in human brain and behaviour

The perception of animate things is of great behavioural importance to humans. Despite the prominence of the distinct brain and behavioural responses to animate and inanimate things, however, it remains unclear which of several commonly entangled properties underlie these observations. Here, we investigate the importance of five dimensions of animacy: being alive, looking like an animal, having agency, having mobility, and being unpredictable in brain (fMRI, EEG) and behaviour (property and similarity judgments) of 19 subjects using a stimulus set of 128 images that disentangles the five dimensions (optimized by a genetic algorithm). Our results reveal a differential pattern across brain and behaviour. The living/non-living distinction (being alive) was prominent in judgments, but despite its prominence in neuroscience literature, did not explain variance in brain representations. The other dimensions of animacy explained variance in both brain and behaviour. The having agency dimension explained more variance in higher-level visual areas, consistent with higher cognitive contributions. The being unpredictable dimension instead captured representations in both lower and higher-level visual cortex, possibly because unpredictable things require attention. Animacy is multidimensional and our results show that distinct dimensions are differentially represented in human brain and behaviour.

COVID-19 pandemic lockdown responses from an emotional perspective: Family function as a differential pattern among older adults

Family can be an essential resource at times of loss or vital crisis. Loneliness and isolation in older adults might have serious negative consequences for their mental health. For this reason, this research aims to analyze the role of family function in the anxiety and depression experienced by older adults during the pandemic caused by COVID-19. Participants were 882 Spanish community-dwelling adults over 60 years of age. Sociodemographic characteristics, characteristics related to the coronavirus, self-perceived health, family function, avoidance, depression, and anxiety were analyzed. Data suggest a buffering effect of family function on anxiety and depression during the pandemic. Furthermore, being unmarried or a female, greater fear of COVID-19, worse self-perceived health, greater avoidance, and worse family function were associated with higher levels of anxiety. Likewise, greater fear of COVID-19, poorer self-perceived health, greater avoidance, and poorer family function, were associated with greater depression. These results point out that family dysfunction is a predisposing factor for the development of the emotional problems of anxiety and depression in older people in potentially stressful and loss situations.

ZIC-cHILIC Functionalized Magnetic Nanoparticle for Rapid and Sensitive Glycopeptide Enrichment from < 1 µL Serum

Due to their unique glycan composition and linkage, protein glycosylation plays significant roles in cellular function and is associated with various diseases. For comprehensive characterization of their extreme structural complexity occurring in >50% of human proteins, time-consuming multi-step enrichment of glycopeptides is required. Here we report zwitterionic n-dodecylphosphocholine-functionalized magnetic nanoparticles (ZIC-cHILIC@MNPs) as a highly efficient affinity nanoprobe for large-scale enrichment of glycopeptides. We demonstrate that ZIC-cHILIC@MNPs possess excellent affinity, with 80–91% specificity for glycopeptide enrichment, especially for sialylated glycopeptide (90%) from biofluid specimens. This strategy provides rapidity (~10 min) and high sensitivity (<1 μL serum) for the whole enrichment process in patient serum, likely due to the rapid separation using magnetic nanoparticles, fast reaction, and high performance of the affinity nanoprobe at nanoscale. Using this strategy, we achieved personalized profiles of patients with hepatitis B virus (HBV, n = 3) and hepatocellular carcinoma (HCC, n = 3) at the depth of >3000 glycopeptides, especially for the large-scale identification of under-explored sialylated glycopeptides. The glycoproteomics atlas also revealed the differential pattern of sialylated glycopeptides between HBV and HCC groups. The ZIC-cHILIC@MNPs could be a generic tool for advancing the glycoproteome analysis, and contribute to the screening of glycoprotein biomarkers.

Role of Methylation in Period2 (PER2) Transcription in the Context of the Presence or Absence of Light Signals: Natural and Chemical—Studies on the Pig Model

It has been proposed that carbon monoxide (CO) is a chemical light carrier that is transferred by the humoral pathway from the retina to the brain. Here, we aimed to study how deeply CO is involved in regulating the expression of Period2 gene (PER2), one of the genes maintaining the intrinsic biological clock. In our in vivo experiment, we studied whether CO may be a chemical signal and is also equivalent to natural light in three groups of pigs: Normal: housed in natural conditions without any procedures, Control: adapted and kept in constant darkness, infused with blank plasma, and CO treated: adapted and kept in constant darkness infused with CO-enriched plasma. After the experiment, the animals were slaughtered at two times of day: 12 p.m. and 12 a.m. Next, hypothalamus samples were collected. Quantitative PCR, the DNA methylation of the promoter sequence containing enhancers (E-box) and a functional analysis of the PER2 promoter was performed. qPCR showed a differential pattern of PER2 mRNA expression at daytime oscillation in the examined groups. Pyrosequencing revealed daytime changes in the methylation level of regulatory sites of the examined sequence. Luciferase reporter assay confirmed that E-boxes (CANNTG) drive the expression of the porcine PER2 in vitro. In conclusion, changes in methylation over 24 h may regulate the oscillatory manner of PER2 expression.

Distinct mechanoreceptor pezo-1 isoforms modulate food intake in the nematode Caenorhabditis elegans

Two PIEZO mechanosensitive cation channels, PIEZO1 and PIEZO2, have been identified in mammals, where they are involved in numerous sensory processes. While structurally similar, PIEZO channels are expressed in distinct tissues and exhibit unique properties. How different PIEZOs transduce force, how their transduction mechanism varies, and how their unique properties match the functional needs of the distinct tissues where they are expressed remain all-important unanswered questions. The nematode Caenorhabditis elegans has a single PIEZO ortholog (pezo-1) predicted to have twelve isoforms. These isoforms share many transmembrane domains, but differ in those that distinguish PIEZO1 and PIEZO2 in mammals. Here we use translational and transcriptional reporters to show that long pezo-1 isoforms are selectively expressed in mesodermally derived tissues (such as muscle and glands). In contrast, shorter pezo-1 isoforms are primarily expressed in neurons. In the digestive system, different pezo-1 isoforms appear to be expressed in different cells of the same organ. We show that pharyngeal muscles, glands, and valve rely on long pezo-1 isoforms to respond appropriately to the presence of food. The unique pattern of complementary expression of pezo-1 isoforms suggest that different isoforms possess distinct functions. The number of pezo-1 isoforms in C. elegans, their differential pattern of expression, and their roles in experimentally tractable processes make this an attractive system to investigate the molecular basis for functional differences between members of the PIEZO family of mechanoreceptors.

Aggressiveness of Spanish isolates of Xylella fastidiosa to almond plants of different cultivars under greenhouse conditions

The aggressiveness of Spanish isolates of X. fastidiosa, representing different sequence types, were studied in almond plants of several cultivars by means of the dynamics of the population levels and symptoms, colonization and spread, and dose-response relationships. Pathogen dynamics in almond plants under greenhouse conditions showed doubling times of 2.1 to 2.5 days during the exponential growth phase, with a maximum population size around 35 dpi. A differential pattern in population dynamics was observed between sap and xylem tissue after the exponential growth, as population levels in the xylem tissue remained stable while viable cells in sap decreased. Population levels were higher in two upwards zones than in downwards zones, with respect to the inoculation area. The first symptoms were observed between 20 and 60 dpi, and disease severity increased over time at doubling times of 30 days, with a maximum observed at 120 dpi. Strains tested showed differences in population levels in the cultivars studied and were able to spread with different intensity from contaminated plant parts to new growing shoots after pruning. Two almond isolates showed a different performance in dose-response relationships when inoculated in Avijor cultivar. While IVIA 5387.2 reached higher population levels but showed high ED50 and MID values, IVIA 5901.2 showed low population levels as well as low ED50 and MID values. This study raises implications for the epidemiology of X. fastidiosa in almond crops, estimating doubling times of the pathogen in planta and of symptoms development, as well as showing differential aggressiveness between strains.