Dense cold‐water coral garden of Paragorgia johnsoni suggests the importance of the Mid‐Atlantic Ridge for deep‐sea biodiversity

Mid‐ocean ridges generate a myriad of physical oceanographic processes that favor the supply of food and nutrients to suspension‐ and filter‐feeding organisms, such as cold‐water corals and deep‐sea sponges. However, the pioneering work conducted along the Mid‐Atlantic Ridge failed to report the presence of large and dense living coral reefs, coral gardens, or sponge aggregations. Here, we describe the densest, near‐natural, and novel octocoral garden composed of large red and white colonies of Paragorgia johnsoni Gray, 1862 discovered at 545–595 m depth on the slopes of the Mid‐Atlantic Ridge, in the Azores region. This newly discovered octocoral garden is a good candidate for protection since it fits many of the FAO criteria that define what constitutes a Vulnerable Marine Ecosystem. The observations described here corroborate the existence of a close relationship between the octocoral structure and the ambient currents on ridge‐like topographies, providing new insights into the functioning of mid‐ocean ridges'' ecosystems. The ubiquitous presence of biogenic and geological topographies associated with mid‐ocean ridges, which could act as climate refugia, suggests their global importance for deep‐sea biodiversity. A better understanding of the processes involved is, therefore, required. Our observations may inspire future deep‐sea research initiatives to narrow existing knowledge gaps of biophysical connections with benthic fauna at small spatial scales along mid‐ocean ridges.     

Comparison of freshwater discrimination ability in three species of sea kraits (Laticauda semifasciata, L. laticaudata and L. colubrina)

Three species of amphibious sea kraits (Laticauda spp.) require drinking freshwater to regulate water balance. The extent of terrestriality is known to differ among them. Species with higher extent of terrestriality would drink freshwater accumulated on land, whereas less terrestrial species would rely totally on freshwater that runs into the sea. Consequently, we predicted that the latter species might have a better ability to follow the flow of freshwater or lower salinity water in the sea than the former. We investigated the freshwater discrimination ability of three sea krait species, using a Y-maze apparatus. We found that Laticauda semifasciata and Laticauda laticaudata, less terrestrial species, followed freshwater significantly more frequently than seawater, whereas Laticauda colubrina, more terrestrial species, unbiasedly selected freshwater and seawater. This result supports our prediction and suggests that less terrestrial sea kraits more efficiently access freshwater sources in the sea than highly terrestrial sea kraits. It is likely that behavioral rehydration systems vary among sea kraits in relation to their terrestrial tendency.     

Decay of TRPV3 as the genomic trace of epidermal structure changes in the land‐to‐sea transition of mammals

The epidermis plays an indispensable barrier function in animals. Some species have evolved unique epidermal structures to adapt to different environments. Aquatic and semi‐aquatic mammals (cetaceans, manatees, and hippopotamus) are good models to study the evolution of epidermal structures because of their exceptionally thickened stratum spinosum, the lack of stratum granulosum, and the parakeratotic stratum corneum. This study aimed to analyze an upstream regulatory gene transient receptor potential cation channel, subfamily V, member 3 (TRPV3) of epidermal differentiation so as to explore the association between TRPV3 evolution and epidermal changes in mammals. Inactivating mutations were detected in almost all the aquatic cetaceans and several terrestrial mammals. Relaxed selective pressure was examined in the cetacean lineages with inactivated TRPV3, which might contribute to its exceptionally thickened stratum spinosum as the significant thickening of stratum spinosum in TRPV3 knock‐out mouse. However, functional TRPV3 may exist in several terrestrial mammals due to their strong purifying selection, although they have “inactivating mutations.” Further, for intact sequences, relaxed selective constraints on the TRPV3 gene were also detected in aquatic cetaceans, manatees, and semi‐aquatic hippopotamus. However, they had intact TRPV3, suggesting that the accumulation of inactivating mutations might have lagged behind the relaxed selective pressure. The results of this study revealed the decay of TRPV3 being the genomic trace of epidermal development in aquatic and semi‐aquatic mammals. They provided insights into convergently evolutionary changes of epidermal structures during the transition from the terrestrial to the aquatic environment.     

MiR‐223‐3p inhibits rTp17‐induced inflammasome activation and pyroptosis by targeting NLRP3

The incidence of syphilis caused by Treponema pallidum subsp pallidum (T pallidum) infection is accompanied by inflammatory injuries of vascular endothelial cells. Studies have revealed that T pallidum infection could induce inflammasome activation and pyroptosis in macrophages. MicroRNA‐223‐3p (miR‐223‐3p) was reported to be a negative regulator in inflammatory diseases. The present study aimed to explore whether miR‐223‐3p regulates T pallidum‐induced inflammasome activation and pyroptosis in vascular endothelial cells, and determine the mechanisms which underlie this process. MiR‐223‐3p levels in syphilis and control samples were determined. The biological function of miR‐223‐3p in the NLRP3 inflammasome and pyroptosis was evaluated in T pallidum‐infected human umbilical vein endothelial cells (HUVECs). We observed a dramatic decrease in miR‐223‐3p levels in syphilis patients (n = 20) when compared to healthy controls (n = 20). Moreover, miR‐223‐3p showed a notable inhibitory effect on recombinant Tp17 (rTP17)‐induced caspase‐1 activation, resulting in decrease in IL‐1β production and pyroptosis, which was accompanied by the release of lactate dehydrogenase (LDH) in HUVECs. Additionally, the dual‐luciferase assay confirmed that NLRP3 is a direct target of miR‐223‐3p. Moreover, NLRP3 overexpression or knockdown largely blocked the effects of miR‐223‐3p on T pallidum‐induced inflammasome activation and pyroptosis in HUVECs. Most importantly, a notable negative correlation was observed between miR‐223‐3p and NLRP3, caspase‐1, and IL‐1β, respectively, in the serum of syphilis patients and healthy controls. Taken together, our results reveal that miR‐223‐3p targets NLRP3 to suppress inflammasome activation and pyroptosis in T pallidum‐infected endothelial cells, implying that miR‐223‐3p could be a potential target for syphilis patients.     

Flexibility in Red Sea Tridacna maxima‐Symbiodiniaceae associations supports environmental niche adaptation

Giant clams (Tridacninae) are important members of Indo‐Pacific coral reefs and among the few bivalve groups that live in symbiosis with unicellular algae (Symbiodiniaceae). Despite the importance of these endosymbiotic dinoflagellates for clam ecology, the diversity and specificity of these associations remain relatively poorly studied, especially in the Red Sea. Here, we used the internal transcribed spacer 2 (ITS2) rDNA gene region to investigate Symbiodiniaceae communities associated with Red Sea Tridacna maxima clams. We sampled five sites spanning 1,300 km (10° of latitude, from the Gulf of Aqaba, 29°N, to the Farasan Banks, 18°N) along the Red Sea''s North‐South environmental gradient. We detected a diverse and structured assembly of host‐associated algae with communities demonstrating region and site‐specificity. Specimens from the Gulf of Aqaba harbored three genera of Symbiodiniaceae, Cladocopium, Durusdinium, and Symbiodinium, while at all other sites clams associated exclusively with algae from the Symbiodinium genus. Of these exclusively Symbiodinium‐associating sites, the more northern (27° and 22°) and more southern sites (20° and 18°) formed two separate groupings despite site‐specific algal genotypes being resolved at each site. These groupings were congruent with the genetic break seen across multiple marine taxa in the Red Sea at approximately 19°, and along with our documented site‐specificity of algal communities, contrasted the panmictic distribution of the T. maxima host. As such, our findings indicate flexibility in T. maxima‐Symbiodiniaceae associations that may explain its relatively high environmental plasticity and offers a mechanism for environmental niche adaptation.     

Genome‐wide analysis reveals demographic and life‐history patterns associated with habitat modification in landlocked,deep‐spawning sockeye salmon (Oncorhynchus nerka)

Human‐mediated habitat fragmentation in freshwater ecosystems can negatively impact genetic diversity, demography, and life history of native biota, while disrupting the behavior of species that are dependent on spatial connectivity to complete their life cycles. In the Alouette River system (British Columbia, Canada), dam construction in 1928 impacted passage of anadromous sockeye salmon (Oncorhynchus nerka), with the last records of migrants occurring in the 1930s. Since that time, O. nerka persisted as a resident population in Alouette Reservoir until experimental water releases beginning in 2005 created conditions for migration; two years later, returning migrants were observed for the first time in ~70 years, raising important basic and applied questions regarding life‐history variation and population structure in this system. Here, we investigated the genetic distinctiveness and population history of Alouette Reservoir O. nerka using genome‐wide SNP data (n = 7,709 loci) collected for resident and migrant individuals, as well as for neighboring anadromous sockeye salmon and resident kokanee populations within the Fraser River drainage (n = 312 individuals). Bayesian clustering and principal components analyses based on neutral loci revealed five distinct clusters, largely associated with geography, and clearly demonstrated that Alouette Reservoir resident and migrant individuals are genetically distinct from other O. nerka populations in the Fraser River drainage. At a finer level, there was no clear evidence for differentiation between Alouette Reservoir residents and migrants; although we detected eight high‐confidence outlier loci, they all mapped to sex chromosomes suggesting that differences were likely due to uneven sex ratios rather than life history. Taken together, these data suggest that contemporary Alouette Reservoir O. nerka represents a landlocked sockeye salmon population, constituting the first reported instance of deep‐water spawning behavior associated with this life‐history form. This finding punctuates the need for reassessment of conservation status and supports ongoing fisheries management activities in Alouette Reservoir.     

Oral intake of Lactobacillus plantarum L‐14 extract alleviates TLR2‐ and AMPK‐mediated obesity‐associated disorders in high‐fat‐diet‐induced obese C57BL/6J mice

ObjectivesWhether periodic oral intake of postbiotics positively affects weight regulation and prevents obesity‐associated diseases in vivo is unclear. This study evaluated the action mechanism of Lactobacillus plantarum L‐14 (KTCT13497BP) extract and the effects of its periodic oral intake in a high‐fat‐diet (HFD) mouse model.Materials and methodsMouse pre‐adipocyte 3T3‐L1 cells and human bone marrow mesenchymal stem cells (hBM‐MSC) were treated with L‐14 extract every 2 days during adipogenic differentiation, and the mechanism underlying anti‐adipogenic effects was analysed at cellular and molecular levels. L‐14 extract was orally administrated to HFD‐feeding C57BL/6J mice every 2 days for 7 weeks. White adipose tissue was collected and weighed, and liver and blood serum were analysed. The anti‐adipogenic mechanism of exopolysaccharide (EPS) isolated from L‐14 extract was also analysed using Toll‐like receptor 2 (TLR2) inhibitor C29.ResultsL‐14 extract inhibited 3T3‐L1 and hBM‐MSC differentiation into mature adipocytes by upregulating AMPK signalling pathway in the early stage of adipogenic differentiation. The weight of the HFD + L‐14 group (31.51 ± 1.96 g) was significantly different from that of the HFD group (35.14 ± 3.18 g). L‐14 extract also significantly decreased the serum triacylglycerol/high‐density lipoprotein cholesterol ratio (an insulin resistance marker) and steatohepatitis. In addition, EPS activated the AMPK signalling pathway by interacting with TLR2, consequently inhibiting adipogenesis.ConclusionsEPS from L‐14 extract inhibits adipogenesis via TLR2 and AMPK signalling pathways, and oral intake of L‐14 extract improves obesity and obesity‐associated diseases in vivo. Therefore, EPS can be used to prevent and treat obesity and metabolic disorders.     

Effect of soil microorganisms and labile C availability on soil respiration in response to litter inputs in forest ecosystems: A meta‐analysis

Litter inputs can influence soil respiration directly through labile C availability and, indirectly, through the activity of soil microorganisms and modifications in soil microclimate; however, their relative contributions and the magnitude of any effect remain poorly understood. We synthesized 66 recently published papers on forest ecosystems using a meta‐analysis approach to investigate the effect of litter inputs on soil respiration and the underlying mechanisms involved. Our results showed that litter inputs had a strong positive impact on soil respiration, labile C availability, and the abundance of soil microorganisms, with less of an impact related to soil moisture and temperature. Overall, soil respiration was increased by 36% and 55%, respectively, in response to natural and doubled litter inputs. The increase in soil respiration induced by litter inputs showed a tendency for coniferous forests (50.7%)> broad‐leaved forests (41.3%)> mixed forests (31.9%). This stimulation effect also depended on stand age with 30‐ to 100‐year‐old forests (53.3%) and ≥100‐year‐old forests (50.2%) both 1.5 times larger than ≤30‐year‐old forests (34.5%). Soil microbial biomass carbon and soil dissolved organic carbon increased by 21.0%‐33.6% and 60.3%‐87.7%, respectively, in response to natural and doubled litter inputs, while soil respiration increased linearly with corresponding increases in soil microbial biomass carbon and soil dissolved organic carbon. Natural and doubled litter inputs increased the total phospholipid fatty acid (PLFA) content by 6.6% and 19.7%, respectively, but decreased the fungal/bacterial PLFA ratio by 26.9% and 18.7%, respectively. Soil respiration also increased linearly with increases in total PLFA and decreased linearly with decreases in the fungal/bacterial PLFA ratio. The contribution of litter inputs to an increase in soil respiration showed a trend of total PLFA > fungal/bacterial PLFA ratio > soil dissolved organic carbon > soil microbial biomass carbon. Therefore, in addition to forest type and stand age, labile C availability and soil microorganisms are also important factors that influence soil respiration in response to litter inputs, with soil microorganisms being more important than labile C availability.     

Habitat‐linked genetic structure for white‐crowned sparrow (Zonotrichia leucophrys): Local factors shape population genetic structure

Ecological, environmental, and geographic factors all influence genetic structure. Species with broad distributions are ideal systems because they cover a range of ecological and environmental conditions allowing us to test which components predict genetic structure. This study presents a novel, broad geographic approach using molecular markers, morphology, and habitat modeling to investigate rangewide and local barriers causing contemporary genetic differentiation within the geographical range of three white‐crowned sparrow (Zonotrichia leucophrys) subspecies: Z. l. gambelii, Z. l. oriantha, and Z. l. pugetensis. Three types of genetic markers showed geographic distance between sampling sites, elevation, and ecosystem type are key factors contributing to population genetic structure. Microsatellite markers revealed white‐crowned sparrows do not group by subspecies, but instead indicated four groupings at a rangewide scale and two groupings based on coniferous and deciduous ecosystems at a local scale. Our analyses of morphological variation also revealed habitat differences; sparrows from deciduous ecosystems are larger than individuals from coniferous ecosystems based on principal component analyses. Habitat modeling showed isolation by distance was prevalent in describing genetic structure, but isolation by resistance also had a small but significant influence. Not only do these findings have implications concerning the accuracy of subspecies delineations, they also highlight the critical role of local factors such as habitat in shaping contemporary population genetic structure of species with high dispersal ability.     

Micro‐CT reconstruction reveals the colony pattern regulations of four dominant reef‐building corals

Colonies are the basic geometric building blocks of coral reefs. However, the forming regulations of both colonies and reefs are still not understood adequately. Therefore, in this study, we reconstructed 25 samples using high‐resolution micro‐computed tomography to investigate coral growth patterns and parameters. Our skeleton and canal reconstructions revealed the characteristics of different coral species, and we further visualized the growth axes and growth rings to understand the coral growth directions. We drew a skeleton grayscale map and calculated the coral skeleton void ratios to ascertain the skeletal diversity, devising a method to quantify coral growth. On the basis of the three‐dimensional (3D) reconstructions and growth parameters, we investigated the growth strategies of different coral species. This research increases the breadth of knowledge on how reef‐building corals grow their colonies, providing information on reef‐forming regulations. The data in this paper contain a large amount of coral growth information, which can be used in further research on reef‐forming patterns under different conditions. The method used in this study can also be applied to animals with porous skeletons.     

IFN‐γ+IL‐17+Th17 cells regulate fibrosis through secreting IL‐21 in systemic scleroderma

This study aimed to explore the function of IFN‐γ⁺IL‐17⁺Th17 cells on fibrosis in systemic scleroderma (SSc). Blood and skin samples were collected from 20 SSc cases and 10 healthy individuals. The percentage of IFN‐γ⁺IL‐17⁺Th17 cells was detected using flow cytometry. The in vitro induction of IFN‐γ⁺IL‐17⁺Th17 cells was performed adopting PHA and rIL‐12. Gene expression was detected via quantitative real‐time polymerase chain reaction (qRT‐PCR), whereas western blot analysis was adopted for protein analysis. The distribution of IFN‐γ⁺IL‐17⁺Th17 cells was significantly increased in SSc cases and positively correlated with SSc stages (P = .031), disease duration (P = .016), activity (P = .025) and skin scores (P < .001). In vitro, IFN‐γ⁺IL‐17⁺Th17 cells could promote the expressions of α‐SMA and COL1A1, revealing increased fibroblasts’ proliferation and enhanced collagen‐secreting capacity. In addition, IL‐21 expression was significantly increased in co‐culture medium of IFN‐γ⁺IL‐17⁺Th17 cells and fibroblasts (P < .001). IL‐21 neutralizer treatment resulted in the down‐regulation of α‐SMA and COL1A1. IL‐21 was confirmed as an effector of IFN‐γ⁺IL‐17⁺Th17 cells in fibrosis process. The distribution of IFN‐γ⁺IL‐17⁺Th17 cells was significantly increased in SSc cases and positively correlated with disease activity. IFN‐γ⁺IL‐17⁺Th17 cells could promote fibroblast proliferation and enhance collagen‐secreting ability via producing IL‐21, thus contributing to fibrosis in SSc.     

Sex‐ and strain‐specific effects of mitochondrial uncoupling on age‐related metabolic diseases in high‐fat diet‐fed mice

Mild uncoupling of oxidative phosphorylation is an intrinsic property of all mitochondria and may have evolved to protect cells against the production of damaging reactive oxygen species. Therefore, compounds that enhance mitochondrial uncoupling are potentially attractive anti‐aging therapies; however, chronic ingestion is associated with a number of unwanted side effects. We have previously developed a controlled‐release mitochondrial protonophore (CRMP) that is functionally liver‐directed and promotes oxidation of hepatic triglycerides by causing a subtle sustained increase in hepatic mitochondrial inefficiency. Here, we sought to leverage the higher therapeutic index of CRMP to test whether mild mitochondrial uncoupling in a liver‐directed fashion could reduce oxidative damage and improve age‐related metabolic disease and lifespan in diet‐induced obese mice. Oral administration of CRMP (20 mg/[kg‐day] × 4 weeks) reduced hepatic lipid content, protein kinase C epsilon activation, and hepatic insulin resistance in aged (74‐week‐old) high‐fat diet (HFD)‐fed C57BL/6J male mice, independently of changes in body weight, whole‐body energy expenditure, food intake, or markers of hepatic mitochondrial biogenesis. CRMP treatment was also associated with a significant reduction in hepatic lipid peroxidation, protein carbonylation, and inflammation. Importantly, long‐term (49 weeks) hepatic mitochondrial uncoupling initiated late in life (94–104 weeks), in conjugation with HFD feeding, protected mice against neoplastic disorders, including hepatocellular carcinoma (HCC), in a strain and sex‐specific manner. Taken together, these studies illustrate the complex variation of aging and provide important proof‐of‐concept data to support further studies investigating the use of liver‐directed mitochondrial uncouplers to promote healthy aging in humans.     

On‐site genetic analysis for species identification using lab‐on‐a‐chip

This paper presents a microfluidic device capable of performing genetic analysis on dung samples to identify White Rhinoceros (Ceratotherium simum). The development of a microfluidic device, which can be used in the field, offers a portable and cost‐effective solution for DNA analysis and species identification to aid conservation efforts. Optimization of the DNA extraction processes produced equivalent yields compared to conventional kit‐based methods within just 5 minutes. The use of a color‐changing loop‐mediated isothermal amplification reaction for simultaneous detection of the cytochrome B sequence of C. simum enabled positive results to be obtained within as little as 30 minutes. Field testing was performed at Knowsley Safari to demonstrate real‐world applicability of the microfluidic device for testing of biological samples.     

Aging‐related cell type‐specific pathophysiologic immune responses that exacerbate disease severity in aged COVID‐19 patients

Coronavirus disease 2019 (COVID‐19) is especially severe in aged patients, defined as 65 years or older, for reasons that are currently unknown. To investigate the underlying basis for this vulnerability, we performed multimodal data analyses on immunity, inflammation, and COVID‐19 incidence and severity as a function of age. Our analysis leveraged age‐specific COVID‐19 mortality and laboratory testing from a large COVID‐19 registry, along with epidemiological data of ~3.4 million individuals, large‐scale deep immune cell profiling data, and single‐cell RNA‐sequencing data from aged COVID‐19 patients across diverse populations. We found that decreased lymphocyte count and elevated inflammatory markers (C‐reactive protein, D‐dimer, and neutrophil–lymphocyte ratio) are significantly associated with age‐specific COVID‐19 severities. We identified the reduced abundance of naïve CD8 T cells with decreased expression of antiviral defense genes (i.e., IFITM3 and TRIM22) in aged severe COVID‐19 patients. Older individuals with severe COVID‐19 displayed type I and II interferon deficiencies, which is correlated with SARS‐CoV‐2 viral load. Elevated expression of SARS‐CoV‐2 entry factors and reduced expression of antiviral defense genes (LY6E and IFNAR1) in the secretory cells are associated with critical COVID‐19 in aged individuals. Mechanistically, we identified strong TGF‐beta‐mediated immune–epithelial cell interactions (i.e., secretory‐non‐resident macrophages) in aged individuals with critical COVID‐19. Taken together, our findings point to immuno‐inflammatory factors that could be targeted therapeutically to reduce morbidity and mortality in aged COVID‐19 patients.     

Even patients with mild COVID‐19 symptoms after SARS‐CoV‐2 infection show prolonged altered red blood cell morphology and rheological parameters

Infection with the novel severe acute respiratory syndrome coronavirus‐2 (SARS‐CoV‐2) and the associated coronavirus disease‐19 (COVID‐19) might affect red blood cells (RBC); possibly altering oxygen supply. However, investigations of cell morphology and RBC rheological parameters during a mild disease course are lacking and thus, the aim of the study. Fifty individuals with mild COVID‐19 disease process were tested after the acute phase of SARS‐CoV‐2 infection (37males/13 females), and the data were compared to n = 42 healthy controls (30 males/12 females). Analysis of venous blood samples, taken at rest, revealed a higher percentage of permanently elongated RBC and membrane extensions in COVID‐19 patients. Haematological parameters and haemoglobin concentration, MCH and MCV in particular, were highly altered in COVID‐19. RBC deformability and deformability under an osmotic gradient were significantly reduced in COVID‐19 patients. Higher RBC‐NOS activation was not capable to at least in part counteract these reductions. Impaired RBC deformability might also be related to morphological changes and/or increased oxidative state. RBC aggregation index remained unaffected. However, higher shear rates were necessary to balance the aggregation‐disaggregation in COVID‐19 patients which might be, among others, related to morphological changes. The data suggest prolonged modifications of the RBC system even during a mild COVID‐19 disease course.     

Simulated hurricane‐induced changes in light and nutrient regimes change seedling performance in Everglades forest‐dominant species

Wind damage from cyclones can devastate the forest canopy, altering environmental conditions in the understory that affect seedling growth and plant community regeneration. To investigate the impact of hurricane‐induced increases in light and soil nutrients as a result of canopy defoliation, we conducted a two‐way factorial light and nutrient manipulation in a shadehouse experiment. We measured seedling growth of the dominant canopy species in the four Everglades forest communities: pine rocklands (Pinus elliottii var densa), cypress domes (Taxodium distichum), hardwood hammocks, and tree islands (Quercus virginiana and Bursera simaruba). Light levels were full sun and 50% shade, and nutrient levels coupled with an additional set of individuals that were subjected to a treatment mimicking the sudden effects of canopy opening from hurricane‐induced defoliation and the corresponding nutrient pulse. Seedlings were measured weekly for height growth and photosynthesis, with seedlings being harvested after 16 weeks for biomass, leaf area, and leaf tissue N and ¹³C isotope ratio. Growth rates and biomass accumulation responded more to differences in soil nutrients than differences in light availability, with largest individuals being in the high nutrient treatments. For B. simaruba and P. elliottii, the highest photosynthetic rates occurred in the high light, high nutrient treatment, while T. distichum and Q. virginiana photosynthetic rates were highest in low light, high nutrient treatment. Tissue biomass allocation patterns remained similar across treatments, except for Q. virginiana, which altered above‐ and belowground biomass allocation to increase capture of limiting soil and light resources. In response to the hurricane simulation treatment, height growth increased rapidly for Q. virginiana and B. simaruba, with nonsignificant increases for the other two species. We show here that ultimately, hurricane‐adapted, tropical species may be more likely to recolonize the forest canopy following a large‐scale hurricane disturbance.     

Neutralization of SARS‐CoV‐2 by highly potent,hyperthermostable, and mutation‐tolerant nanobodies

Monoclonal anti‐SARS‐CoV‐2 immunoglobulins represent a treatment option for COVID‐19. However, their production in mammalian cells is not scalable to meet the global demand. Single‐domain (VHH) antibodies (also called nanobodies) provide an alternative suitable for microbial production. Using alpaca immune libraries against the receptor‐binding domain (RBD) of the SARS‐CoV‐2 Spike protein, we isolated 45 infection‐blocking VHH antibodies. These include nanobodies that can withstand 95°C. The most effective VHH antibody neutralizes SARS‐CoV‐2 at 17–50 pM concentration (0.2–0.7 µg per liter), binds the open and closed states of the Spike, and shows a tight RBD interaction in the X‐ray and cryo‐EM structures. The best VHH trimers neutralize even at 40 ng per liter. We constructed nanobody tandems and identified nanobody monomers that tolerate the K417N/T, E484K, N501Y, and L452R immune‐escape mutations found in the Alpha, Beta, Gamma, Epsilon, Iota, and Delta/Kappa lineages. We also demonstrate neutralization of the Beta strain at low‐picomolar VHH concentrations. We further discovered VHH antibodies that enforce native folding of the RBD in the E. coli cytosol, where its folding normally fails. Such “fold‐promoting” nanobodies may allow for simplified production of vaccines and their adaptation to viral escape‐mutations.     

Home‐site fidelity and homing behavior of the big‐headed turtle Platysternon megacephalum

Site fidelity refers to the restriction of dispersal distance of an animal and its tendency to return to a stationary site. To our knowledge, the homing ability of freshwater turtles and their fidelity is reportedly very low in Asia. We examined mark–recapture data spanning a 4‐year period in Diaoluoshan National Nature Reserve, Hainan Province, China, to investigate the site fidelity and homing behavior of big‐headed turtles Platysternon megacephalum. A total of 11 big‐headed turtles were captured, and all individuals were used in this mark–recapture study. The site fidelity results showed that the adult big‐headed turtles (n = 4) had a 71.43% recapture rate in the original site after their release at the same site, whereas the juveniles (n = 1) showed lower recapture rates (0%). Moreover, the homing behavior results showed that the adults (n = 5) had an 83.33% homing rate after displacement. Adult big‐headed turtles were able to return to their initial capture sites (home) from 150 to 2,400 m away and precisely to their home sites from either upstream or downstream of their capture sites or even from other streams. However, none of the juveniles (n = 4) returned home, despite only being displaced 25–150 m away. These results indicated that the adult big‐headed turtles showed high fidelity to their home site and strong homing ability. In contrast, the juvenile turtles may show an opposite trend but further research is needed.     

Mitochondrial aconitase 1 regulates age‐related memory impairment via autophagy/mitophagy‐mediated neural plasticity in middle‐aged flies

Age‐related memory impairment (AMI) occurs in many species, including humans. The underlying mechanisms are not fully understood. In wild‐type Drosophila (w¹¹¹⁸ ), AMI appears in the form of a decrease in learning (3‐min memory) from middle age (30 days after eclosion [DAE]). We performed in vivo, DNA microarray, and behavioral screen studies to identify genes controlling both lifespan and AMI and selected mitochondrial Acon1 (mAcon1). mAcon1 expression in the head of w¹¹¹⁸ decreased with age. Neuronal overexpression of mAcon1 extended its lifespan and improved AMI. Neuronal or mushroom body expression of mAcon1 regulated the learning of young (10 DAE) and middle‐aged flies. Interestingly, acetyl‐CoA and citrate levels increased in the heads of middle‐aged and neuronal mAcon1 knockdown flies. Acetyl‐CoA, as a cellular energy sensor, is related to autophagy. Autophagy activity and efficacy determined by the positive and negative changes in the expression levels of Atg8a‐II and p62 were proportional to the expression level of mAcon1. Levels of the presynaptic active zone scaffold protein Bruchpilot were inversely proportional to neuronal mAcon1 levels in the whole brain. Furthermore, mAcon1 overexpression in Kenyon cells induced mitophagy labeled with mt‐Keima and improved learning ability. Both processes were blocked by pink1 knockdown. Taken together, our results imply that the regulation of learning and AMI by mAcon1 occurs via autophagy/mitophagy‐mediated neural plasticity.