Labile assembly of a tardigrade protein induces biostasis

Tardigrades are microscopic animals that survive desiccation by inducing biostasis. To survive drying tardigrades rely on intrinsically disordered CAHS proteins, which also function to prevent perturbations induced by drying in vitro and in heterologous systems. CAHS proteins have been shown to form gels both in vitro and in vivo, which has been speculated to be linked to their protective capacity. However, the sequence features and mechanisms underlying gel formation and the necessity of gelation for protection have not been demonstrated. Here we report a mechanism of fibrillization and gelation for CAHS D similar to that of intermediate filament assembly. We show that in vitro, gelation restricts molecular motion, immobilizing and protecting labile material from the harmful effects of drying. In vivo, we observe that CAHS D forms fibrillar networks during osmotic stress. Fibrillar networking of CAHS D improves survival of osmotically shocked cells. We observe two emergent properties associated with fibrillization; (i) prevention of cell volume change and (ii) reduction of metabolic activity during osmotic shock. We find that there is no significant correlation between maintenance of cell volume and survival, while there is a significant correlation between reduced metabolism and survival. Importantly, CAHS D's fibrillar network formation is reversible and metabolic rates return to control levels after CAHS fibers are resolved. This work provides insights into how tardigrades induce reversible biostasis through the self-assembly of labile CAHS gels.

Modulation of PI3K/Akt/GSK3β signaling cascade through G protein-coupled receptor 55 (GPR55) activation: Prenatal lysophosphatidylinositol attenuates valproic acid-induced synaptic abnormalities and mitochondrial dysfunction

AIMS

Dysregulation of PI3K/Akt/GSK3β signaling has been implicated in various neurological disorders, including autism spectrum disorder (ASD). G protein-coupled receptor 55 (GPR55) has recently emerged as a potential regulator of this signaling cascade. This study explores the intricate modulation of the PI3K/Akt/GSK3β signaling cascade via GPR55 activation and its potential therapeutic implications in the context of autism-associated neuronal impairments.

MAIN METHODS

Valproic acid (VPA) was administered on embryonic day 12 (E12) to induce ASD, and lysophosphatidylinositol (LPI), a GPR55 agonist, was used prenatally to modulate the receptor activity. Golgi-cox staining was performed to observe neuronal morphology, and Hematoxylin and eosin (H and E) staining was carried out to quantify damaged neurons. Enzyme-linked immunosorbent assay (ELISA) was implemented to identify molecular mediators involved in neuroprotection.

KEY FINDINGS

Prenatal VPA exposure resulted in significant abnormalities in synaptic development, which were further evidenced by impairments in social interaction and cognitive function. When LPI was administered, most of the synaptic abnormalities were alleviated, as reflected by higher neuron and dendritic spine count. LPI treatment also reduced cytoplasmic cytochrome c concentration and related neuronal cell death. Mechanistically, GPR55 activation by LPI increases the expression of phospho-Akt and phospho-GSK3β, leading to the activation of this signaling in the process of rescuing synaptic abnormalities and mitochondria-mediated neuronal apoptosis.

SIGNIFICANCE

The observed therapeutic effects of GPR55 activation shed light on its significance as a prospective target for ameliorating mitochondrial dysfunction and dendritic spine loss, offering novel prospects for developing targeted interventions to alleviate the neuropathological causes of ASD.

Effects of supplementing milk replacer with essential amino acids on blood metabolites, immune response, and nitrogen metabolism of Holstein calves exposed to an endotoxin

This study evaluated the effects of supplementing calf milk replacer with essential AA on immune responses, blood metabolites, and nitrogen metabolism of 32 Holstein bull calves [28 d of age, 44 ± 0.8 kg of body weight (BW)] exposed to lipopolysaccharide (LPS). Calves were bottle-fed a commercial milk replacer (20% crude protein and 20% fat, dry matter basis) twice daily along with a calf starter (19% crude protein, dry matter basis) for 45 d. The experiment was a randomized complete block design and treatments were a 2 × 2 factorial arrangement. Treatments were milk replacer (fed twice daily at 0.5 kg/d of powder) supplemented with or without 10 essential AA (+AA vs. -AA), and subcutaneous injection of sterile saline with or without LPS (+LPS vs. -LPS) at 3 h after the morning feeding on d 15 (4 µg LPS per kg of BW) and 17 (2 µg LPS per kg of BW). Calves also received a 2-mL subcutaneous injection of ovalbumin (6 mg of ovalbumin/mL) on d 16 and 30. Rectal temperature and blood samples were collected on d 15 before LPS injection and at h 4, 8, 12, and 24 thereafter. From d 15 to 19, total fecal and urinary output were collected, and feed refusals were documented. Rectal temperature was greater in +LPS than -LPS calves at h 4, 8, and 12 after LPS injection. Serum cortisol was greater for +LPS than -LPS at h 4 after LPS exposure. At d 28, serum antiovalbumin IgG level was greater in +LPS +AA calves compared with +LPS -AA. Serum glucose was lower for +LPS than -LPS at h 4 and 8. Serum insulin was greater in +LPS than -LPS calves. Plasma concentrations of Thr, Gly, Asn, Ser, and hydroxyproline were lower for +LPS versus -LPS calves. Plasma concentrations of Met, Leu, Phe, His, Ile, Trp, Thr, and Orn were greater in +AA calves than -AA calves. Plasma urea N and N retention were not different among LPS and AA treatments. The lower concentrations of AA in +LPS than -LPS calves indicate higher demand for AA in immuno-compromised calves fed milk replacer. Additionally, higher concentration of ovalbumin-specific IgG level in +LPS calves supplemented with +AA compared with +LPS calves with -AA suggests that supplementing AA to immune-compromised calves might improve immune status.

Neuropharmacological Effects of Chassalia curviflora (Rubiaceae) Leaves in Swiss Albino Mice Model

The current study aimed to investigate the neuropharmacological properties of ethanol, acetone, and ethyl acetate leaf extracts of Chassalia curviflora (C. curviflora) in mouse models. The neuropharmacological properties of this plant were studied on Swiss albino mice at dosages of 50, 100, and 200 mg/kg body weight in thiopental sodium-induced sleeping time test, and at dosages of 100 and 200 mg/kg body weight in other tests. The extracts caused a marked reduction in the initiation and sleep length (P<0.05) in studies on thiopental sodium-induced sleeping time at dosages of 100 and 200 mg/kg and a significant decrease (P<0.05) was found in terms of unconstrained locomotor and explorative activities in both hole crossing and open field tests at dosages of 100 and 200 mg/kg. Furthermore, the extracts increased sleeping time with a dosage-dependent onset of action. The hole-board test extracts also reduced the number of head dips at dosages of 100 and 200 mg/kg (P<0.05). It was found in this study that C. curviflora had the best neuropharmacological properties at a dosage of 200 ml/kg. Our findings also showed that all of the extracts from C. curviflora were experimentally active in an in vivo model. The study results suggested that the leaves had strong anti-depressant and hypnotic CNS properties that might be exploited for neuropharmacological adjuvant therapy in conventional medicine. However, pharmacological studies are warranted to explore the active substances and the mode of action.

Pandemic Now and Then: A Historical Perspective of Non-Pharmaceutical Interventions Adopted In Covid-19

The coronavirus disease 2019 (COVID-19), first reported in Wuhan, China is now a major global health threat - a pandemic. Public health control measures are the cornerstones in the fight against COVID-19 in the absence of an effective vaccine or proven treatment. The aim of this review was to explore the historical use case of various public health measures adopted today to tackle COVID-19 spread. Although our knowledge about this novel coronavirus transmission is evolving over time, the fundamental non-pharmaceutical interventions e.g., handwashing, wearing a mask, physical distancing, isolation, quarantine and border control which are adopted globally at present are not new. This review highlighted that historically and religiously similar approaches were practised in the medieval past for controlling disease outbreaks. The successful implementation of the public health control measures largely depends on health systems resilience, community engagement and changes in population behaviour. Combined global efforts are essential to strengthen health systems, improve the capability of research and transparent information sharing with both public and international bodies to combat the pandemic.

Proximate composition, texture analysis and sensory evaluation of keropok lekor formulated with herbs and spices

Keropok lekor a fish-based sausage is a popular traditional food item in Terengganu state, Malaysia. This study aimed to develop a new flavor and taste of keropok lekor. Common spices such as cumin, coriander, cinnamon, cardamom, bay leaf, nutmeg, clove, onion, ginger, garlic were used to develop a new flavor of keropok lekor. A total of 5 samples, including two original and three developed keropok lekor samples were prepared. This study also evaluated the proximate composition of two raw samples (Original and developed). The results of the proximate analysis showed a significant difference (p<0.05) in all parameters except the fiber content. Hardness, springiness, and chewiness of the samples were measured by using TA-XTplus texture analyzer. There was a significant difference in the hardness level between original and developed sample. Finally, sensory evaluation according to six attributes such as color, odors, texture, flavor, taste and overall acceptability was done by 39 panelists. A 7-point hedonic scale ranging from “dislike very much” to “like very much” was employed in sensory testing. There was a significant difference (p<0.05) in all the sensory parameters evaluated. The results showed that most of the respondents preferred the developed samples over the original samples. Developed fried keropok lekor with bread crumb was the most acceptable one.

Modelling the failure modes in geobag revetments

In recent years, sand filled geotextile bags (geobags) have been used as a means of long-term riverbank revetment stabilization. However, despite their deployment in a significant number of locations, the failure modes of such structures are not well understood. Three interactions influence the geobag performance, i.e. geobag-geobag, geobag-water flow and geobag-water flow-river bank. The aim of the research reported here is to develop a detailed understanding of the failure mechanisms in a geobag revetment using a discrete element model (DEM) validated by laboratory data. The laboratory measured velocity data were used for preparing a mapped velocity field for a coupled DEM simulation of geobag revetment failure. The validated DEM model could identify well the critical bag location in varying water depths. Toe scour, one of the major instability factors in revetments, and its influence on the bottom-most layer of the bags were also reasonably represented in this DEM model. It is envisaged that the use of a DEM model will provide more details on geobag revetment performance in riverbanks.

Screening of Ethanol, Petroleum Ether and Chloroform Extracts of Medicinal Plants, Lawsonia inermis L. and Mimosa pudica L. for Antibacterial Activity

Organic extracts (ethanol, petroleum ether and chloroform) of two medicinal plants Lawsonia inermis L. and Mimosa pudica L. were proven for antibacterial properties against 15 Gram-positive and Gram-negative human pathogenic bacteria. Among the three types of extracts tested, ethanol extract was found to possess maximum antibacterial activity. The diameter of the zone of inhibition of bacterial growth showed that Gram-negative bacteria are more sensitive than Gram-positive bacteria to plant extracts. Between the two plants species studied, Lawsonia inermis extract showed more antibacterial activity compared to Mimosa pudica extract.