In situ short-term responses of Amazonian understory plants to elevated CO2.

The response of plants to increasing atmospheric CO2 depends on the ecological context where the plants are found. Several experiments with elevated CO2 (eCO2) have been done worldwide, but the Amazonian forest understory has been neglected. As the central Amazon is limited by light and phosphorus, understanding how understory responds to eCO2 is important for foreseeing how the forest will function in the future. In the understory of a natural forest in the Central Amazon, we installed four open-top chambers as control replicates and another four under eCO2 (+250 ppm above ambient levels). Under eCO2, we observed increases in carbon assimilation rate (67%), maximum electron transport rate (19%), quantum yield (56%), and water use efficiency (78%). We also detected an increase in leaf area (51%) and stem diameter increment (65%). Central Amazon understory responded positively to eCO2 by increasing their ability to capture and use light and the extra primary productivity was allocated to supporting more leaf and conducting tissues. The increment in leaf area while maintaining transpiration rates suggests that the understory will increase its contribution to evapotranspiration. Therefore, this forest might be less resistant in the future to extreme drought, as no reduction in transpiration rates were detected.

Comparative morphology of oral glands in snakes of the family Homalopsidae reveals substantial variation and additional independent origins of salt glands within Serpentes.

Using diffusible iodine-based contrast-enhanced computed tomography (diceCT), we examined the morphology of the oral glands of 12 species of the family Homalopsidae. Snakes of this family exhibit substantial interspecific morphological variation in their oral glands. Particular variables are the venom glands, ranging from large (e.g., Subsessor bocourti) to small (e.g., Erpeton tentaculatum). The supra- and infralabial glands are more uniform in morphology, being the second most developed in almost all the sampled species. Premaxillary glands distinct from the supralabial glands were observed in five species (Myron richardsonii, Bitia hydroides, Cantoria violacea, Fordonia leucobalia, and Gerarda prevostiana), in addition to Cerberus rynchops, the only species in which this condition was previously documented associated with the excretion of salt. In the three species of the saltwater group of homalopsids (C. violacea, F. leucobalia, and G. prevostiana), the premaxillary glands also extend posteriorly, occupying a large area above the supralabial gland, a condition not observed in any other species of snake studied thus far. Character evolution analyses indicate that premaxillary glands differentiated from the supralabial gland and evolved independently three or four times in the family, always in lineages that invaded marine habitats. Our results suggest that the differentiated premaxillary glands are likely salt glands, as is the case in C. rynchops. If corroborated, this increases to six or seven the number of independent evolutionary origins of salt glands in snakes that have undergone an evolutionary transition to marine life.

Mobile Robot + IoT: Project of Sustainable Technology for Sanitizing Broiler Poultry Litter.

The traditional aviary decontamination process involves farmers applying pesticides to the aviary's ground. These agricultural defenses are easily dispersed in the air, making the farmers susceptible to chronic diseases related to recurrent exposure. Industry 5.0 raises new pillars of research and innovation in transitioning to more sustainable, human-centric, and resilient companies. Based on these concepts, this paper presents a new aviary decontamination process that uses IoT and a robotic platform coupled with ozonizer (O3) and ultraviolet light (UVL). These clean technologies can successfully decontaminate poultry farms against pathogenic microorganisms, insects, and mites. Also, they can degrade toxic compounds used to control living organisms. This new decontamination process uses physicochemical information from the poultry litter through sensors installed in the environment, which allows accurate and safe disinfection. Different experimental tests were conducted to construct the system. First, tests related to measuring soil moisture, temperature, and pH were carried out, establishing the range of use and the confidence interval of the measurements. The robot's navigation uses a back-and-forth motion that parallels the aviary's longest side because it reduces the number of turns, reducing energy consumption. This task becomes more accessible because of the aviaries' standardized geometry. Furthermore, the prototype was tested in a real aviary to confirm the innovation, safety, and effectiveness of the proposal. Tests have shown that the UV + ozone combination is sufficient to disinfect this environment.

SARS-CoV-2 Spillback to Wild Coatis in Sylvatic-Urban Hotspot, Brazil.

We tested coatis (Nasua nasua) living in an urban park near a densely populated area of Brazil and found natural SARS-CoV-2 Zeta variant infections by using quantitative reverse transcription PCR, genomic sequencing, and serologic surveillance. We recommend a One Health strategy to improve surveillance of and response to COVID-19.

The best structure of the Tampa Scale for Kinesiophobia for patients with chronic low back pain has two domains and nine items.

PURPOSE: To identify the best internal structure of the Tampa Scale for Kinesiophobia in chronic low back pain patients. DESIGN: Questionnaire validation study was designed for this study. SETTING: This study was conducted in physical therapy facility. SUBJECTS: Respondents reporting chronic low back pain (≥3 points on the 11-point Numerical Pain Rating Scale). MAIN MEASURES: We included participants of both sexes, with a self-report of low back pain ≥3 months and with pain intensity ≥3 on the 11-point Numerical Pain Rating Scale; participants also answered the Roland-Morris Disability Questionnaire and the Pain-Related Catastrophizing Thoughts Scale for low back pain disability and catastrophizing, respectively. The dimensionality and number of items of the Tampa Scale for Kinesiophobia were evaluated using the confirmatory factor analysis. Criterion validity was assessed using Spearman's correlation coefficient using the original version of the 17-item Tampa Scale for Kinesiophobia as the gold standard. RESULTS: A total of 122 participants were included, with mean values of low back pain duration ≥48 months, pain intensity >5 and disability >8. Tampa Scale for Kinesiophobia structure with two domains and nine items was the most suitable, with adequate values in all fit indices (Chi-square/degree of freedom <3, Comparative Fit Index and Tucker-Lewis Index >0.90, and root mean square error of approximation <0.08) and lower Akaike information criterion and Bayesian information criterion values. We observed a high correlation between the 17-item Tampa Scale for Kinesiophobia and the activity avoidance domain (rho = 0.850, P < 0.001) and somatic focus domain (rho = 0.792, P < 0.001) of the nine-item Tampa Scale for Kinesiophobia. CONCLUSION: Tampa Scale for Kinesiophobia structure with two domains (activity avoidance and somatic focus) and nine items is the most suitable for patients with chronic low back pain.

Adaptive Parameters for LoRa-Based Networks Physical-Layer.

Sub-GHz communication provides long-range coverage with low power consumption and reduced deployment cost. LoRa (Long-Range) has emerged, among existing LPWAN (Low Power Wide Area Networks) technologies, as a promising physical layer alternative to provide ubiquitous connectivity to outdoor IoT devices. LoRa modulation technology supports adapting transmissions based on parameters such as carrier frequency, channel bandwidth, spreading factor, and code rate. In this paper, we propose SlidingChange, a novel cognitive mechanism to support the dynamic analysis and adjustment of LoRa network performance parameters. The proposed mechanism uses a sliding window to smooth out short-term variations and reduce unnecessary network re-configurations. To validate our proposal, we conducted an experimental study to evaluate the performance concerning the Signal-to-Noise Ratio (SNR) parameter of our SlidingChange against InstantChange, an intuitive mechanism that considers immediate performance measurements (parameters) for re-configuring the network. The SlidingChange is compared with LR-ADR too, a state-of-the-art-related technique based on simple linear regression. The experimental results obtained from a testbed scenario demonstrated that the InstanChange mechanism improved the SNR by 4.6%. When using the SlidingChange mechanism, the SNR was around 37%, while the network reconfiguration rate was reduced by approximately 16%.

A Biosafety Level 2 Mouse Model for Studying Betacoronavirus-Induced Acute Lung Damage and Systemic Manifestations.

The emergence of life-threatening zoonotic diseases caused by betacoronaviruses, including the ongoing coronavirus disease 19 (COVID-19) pandemic, has highlighted the need for developing preclinical models mirroring respiratory and systemic pathophysiological manifestations seen in infected humans. Here, we showed that C57BL/6J wild-type mice intranasally inoculated with the murine betacoronavirus murine hepatitis coronavirus 3 (MHV-3) develop a robust inflammatory response leading to acute lung injuries, including alveolar edema, hemorrhage, and fibrin thrombi. Although such histopathological changes seemed to resolve as the infection advanced, they efficiently impaired respiratory function, as the infected mice displayed restricted lung distention and increased respiratory frequency and ventilation. Following respiratory manifestation, the MHV-3 infection became systemic, and a high virus burden could be detected in multiple organs along with morphological changes. The systemic manifestation of MHV-3 infection was also marked by a sharp drop in the number of circulating platelets and lymphocytes, besides the augmented concentration of the proinflammatory cytokines interleukin 1 beta (IL-1ß), IL-6, IL-12, gamma interferon (IFN-γ), and tumor necrosis factor (TNF), thereby mirroring some clinical features observed in moderate and severe cases of COVID-19. Importantly, both respiratory and systemic changes triggered by MHV-3 infection were greatly prevented by blocking TNF signaling, either via genetic or pharmacologic approaches. In line with this, TNF blockage also diminished the infection-mediated release of proinflammatory cytokines and virus replication of human epithelial lung cells infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Collectively, results show that MHV-3 respiratory infection leads to a large range of clinical manifestations in mice and may constitute an attractive, lower-cost, biosafety level 2 (BSL2) in vivo platform for evaluating the respiratory and multiorgan involvement of betacoronavirus infections. IMPORTANCE Mouse models have long been used as valuable in vivo platforms to investigate the pathogenesis of viral infections and effective countermeasures. The natural resistance of mice to the novel betacoronavirus SARS-CoV-2, the causative agent of COVID-19, has launched a race toward the characterization of SARS-CoV-2 infection in other animals (e.g., hamsters, cats, ferrets, bats, and monkeys), as well as adaptation of the mouse model, by modifying either the host or the virus. In the present study, we utilized a natural pathogen of mice, MHV, as a prototype to model betacoronavirus-induced acute lung injure and multiorgan involvement under biosafety level 2 conditions. We showed that C57BL/6J mice intranasally inoculated with MHV-3 develops severe disease, which includes acute lung damage and respiratory distress that precede systemic inflammation and death. Accordingly, the proposed animal model may provide a useful tool for studies regarding betacoronavirus respiratory infection and related diseases.

Pro-inflammatory immune profile mediated by TNF and IFN-γ and regulated by IL-10 is associated to IgG anti-SARS-CoV-2 in asymptomatic blood donors.

The SARS-CoV-2 virus has infected and killed millions of people, but little is known about the risk factors that lead to the development of severe, mild or asymptomatic conditions after infection. The individual immune response and the balance of cytokines and chemokines have been shown to be important for the prognosis of patients. Additionally, it is essential to understand how the production of specific antibodies with viral neutralizing capacity is established. In this context, this study aimed to identify positive individuals for IgG anti-SARS-CoV-2 in a large population of blood donors (n = 7837) to establish their immune response profile and to evaluate its viral neutralization capacity. The prevalence found for IgG anti-SARS-CoV-2 was 5.6% (n = 441), with male blood donors (61.9%) being more prevalent among the positive ones. The results showed that positive individuals for IgG anti-SARS-CoV-2 have high serum concentrations of chemokines, TNF, IFN-γ and IL-10. The analyses showed that the positivity index for IgG anti-SARS-CoV-2 is associated with the neutralizing capacity of the antibodies, which, in turn, is significantly related to lower serum concentrations of CCL5 and CXCL10. The results allow us to hypothesize that the development and maintenance of IgG anti-SARS-CoV-2 antibodies in infected individuals occurs in a pro-inflammatory microenvironment well regulated by IL-10 with great capacity for recruiting cells from the innate and adaptive immune systems.

Detection of Influenza A(H3N2) Virus RNA in Donated Blood.

Influenza A virus infection has rarely been documented to cause viremia. In 28 blood donations in Brazil that were deferred because of postdonation information, we identified influenza A(H3N2) virus RNA in 1 donation using metagenomic analysis. Our finding implies theoretical risk for viremia and transfusion transmission.

Possible Charge-Transfer-Induced Conductivity Enhancement in TiO2 Microtubes Decorated with Perovskite CsPbBr3 Nanocrystals.

Halide perovskite CsPbBr3 quantum dots (QDs) were synthesized via supersaturated recrystallization process and deposited on the surface of TiO2 microtubes forming local nano-heterostructures. Structural, morphological, and optical characterizations confirm the formation of heterostructures comprised of TiO2 microtube decorated with green-emitting CsPbBr3 nanocrystals. Optical characterizations reveal the presence of two band gap energies corresponding to CsPbBr3 (2.34 eV) and rutile-TiO2 (2.97 eV). Time-resolved photoluminescence decays indicate different charge dynamics when comparing both samples, revealing the interaction of CsPbBr3 QDs with the microtube surface and thus confirming the formation of local nano-heterostructures. The voltage-current measurements in the dark show an abrupt decrease in the electrical resistivity of the CsPbBr3/TiO2 heterostructure reaching almost 95% when compared with the pristine TiO2 microtube. This significant increase in the electrical conductivity is associated with charge transfer from perovskite nanocrystals into the semiconductor microtube, which can be used to fine tune its electronic properties. Besides controlling the electrical conductivity, decoration with semiconducting nanocrystals makes the hollow heterostructure photoluminescent, which can be classified as a multifunctionalization in a single device.

The small molecule AZD6244 inhibits dengue virus replication in vitro and protects against lethal challenge in a mouse model.

Dengue virus (DENV) is the most common mosquito-borne viral disease. The World Health Organization estimates that 400 million new cases of dengue fever occur every year. Approximately 500,000 individuals develop severe and life-threatening complications from dengue fever, such as dengue shock syndrome (DSS) and dengue hemorrhagic fever (DHF), which cause 22,000 deaths yearly. Currently, there are no specific licensed therapeutics to treat DENV illness. We have previously shown that the MEK/ERK inhibitor U0126 inhibits the replication of the flavivirus yellow fever virus. In this study, we demonstrate that the MEK/ERK inhibitor AZD6244 has potent antiviral efficacy in vitro against DENV-2, DENV-3, and Saint Louis encephalitis virus (SLEV). We also show that it is able to protect AG129 mice from a lethal challenge with DENV-2 (D2S20). The molecule is currently undergoing phase III clinical trials for the treatment of non-small-cell lung cancer. The effect of AZD6244 on the DENV life cycle was attributed to a blockade of morphogenesis. Treatment of AG129 mice twice daily with oral doses of AZD6244 (100 mg/kg/day) prevented the animals from contracting dengue hemorrhagic fever (DHF)-like lethal disease upon intravenous infection with 1 × 105 PFU of D2S20. The effectiveness of AZD6244 was observed even when the treatment of infected animals was initiated 1-2 days postinfection. This was also followed by a reduction in viral copy number in both the serum and the spleen. There was also an increase in IL-1ß and TNF-α levels in mice that were infected with D2S20 and treated with AZD6244 in comparison to infected mice that were treated with the vehicle only. These data demonstrate the potential of AZD6244 as a new therapeutic agent to treat DENV infection and possibly other flavivirus diseases.

Effects of 2 Types of Resistance Training Models on Obese Adolescents' Body Composition, Cardiometabolic Risk, and Physical Fitness.

Magnani Branco, BH, Carvalho, IZ, Garcia de Oliveira, H, Fanhani, AP, Machado dos Santos, MC, Pestillo de Oliveira, L, Macente, SB, and Nelson, NJ. Effects of 2 types of resistance training models on obese adolescents' body composition, cardiometabolic risk, and physical fitness. J Strength Cond Res 34(9): 2672-2682, 2020-The main objective of this study was to investigate the effects of 2 types of resistance training (RT) models in conjunction with interdisciplinary interventions by other health professionals to reduce the body fat and cardiometabolic risk of obese adolescents while improving their general health-related physical fitness. The 12-week analyses involved 18 male adolescents who were split into 2 groups (weight lifting: n = 9 and functional: n = 9), with equalization according to the primary muscle group (whenever possible), the effort:pause ratio, and intensity. The results showed reductions in fat mass and body fat, as well as in waist and hip circumferences (p < 0.05) after the intervention period. However, no significant differences were observed in terms of the body mass, body mass index, neck circumference, systolic and diastolic blood pressures, and for lean mass (p > 0.05) after the respective period. Maximal isometric strength, abdominal strength resistance, flexibility, and maximal oxygen consumption all produced significant increases after the interventions (p < 0.05). There were reductions in low-density lipoproteins and triglyceride levels after the intervention period (p < 0.05). For fasting glycemia, high-density lipoproteins, and alanine aminotransferase, no differences were observed (p > 0.05). In addition, no differences were observed in rating of perceived recovery, internal training load, or caloric intake (p > 0.05). With the results presented, it is concluded that both RT methods were effective at reducing both fat mass and body fat, thus improving health-related physical fitness components and decreasing cardiometabolic risk.

Cross-cultural adaptation and psychometric properties of the MMSE and MoCA questionnaires in Tanzanian Swahili for a traumatic brain injury population.

BACKGROUND: Traumatic Brain Injury (TBI) is the most common cause of injury-related death and disability globally, and a common sequelae is cognitive impairment. Addressing post-TBI cognitive deficits is crucial because they affect rehabilitation outcomes, but doing this requires valid and reliable cognitive assessment measures. However, no such instrument has been validated in Tanzania's TBI population. Mini-Mental State Examination (MMSE) and Montreal Cognitive Assessment (MoCA) are two commonly used instruments to measure cognitive impairment, and there have been a few studies reporting their use in post-TBI cognitive assessment. Our aim was to report the psychometric properties of the Swahili version of both scales amongst the TBI population in Tanzania. METHODS: A cross-cultural adaptation committee participated in the translation and content validation process for both questionnaires. Our patient sample consisted of 192 adults with TBI who were admitted to Kilimanjaro Christian Medical Center (KCMC) in Tanzania. Confirmatory factor analysis, reliability and external validity were evaluated. RESULTS: MoCA showed adequate factor loadings (values > 0.50 for all items except items 7 & 10) and adequate reliability (values > 0.70). Factor loadings for most of the MMSE items were below 0.5 and internal consistency was medium (< 0.7). Polychoric correlation between MMSE and MoCA was strong, positive and statistically significant (r = 0.68, p = 0.001); correlation with the cognitive subscale of FIM indicated moderately positive relationships - MMSE (r = 0.35, p = 0.001) and MoCA (r = 0.43, p = 0.001). CONCLUSIONS: With the exception of the language and memory items, MoCA is a valid and reliable instrument for cognitive impairment screening in Tanzania's adult TBI population. On the other hand, MMSE does not appear to be an appropriate tool in this patient group, but its positive correlations with MoCA and cFIM indicate similar theoretical concepts. Both instruments require further validation studies to prove their predictive ability for screening cognitive impairment before they are considered suitable for clinical use.

Cross-cultural adaptation and psychometric properties of the Kessler Scale of Psychological Distress to a traumatic brain injury population in Swahili and the Tanzanian Setting.

BACKGROUND: To evaluate the psychometric properties of a Swahili version of the Kessler Psychological Distress scale in an injury population in Tanzania. METHODS: Swahili version of the Kessler Psychological Distress scale was developed by translation and back-translation by a panel of native speakers of both English and Swahili. The translated instruments were administered to a sample of Tanzanian adults from a traumatic brain injury registry. The content validity, construct validity, reliability, internal structure, and external reliability were analyzed using standard statistical methods. RESULTS: Both translated versions of the Kessler Psychological Distress scale were found to be reliable (>0.85) for all tested versions. Confirmatory factor analysis of one and two factor solution showed adequate results. Kessler Psychological Distress scale scores were strongly correlated to depression and quality of life (R>0.50). CONCLUSIONS: This paper presents the first Swahili adaptations of the Kessler Psychological Distress scale as well as the first validation of these questionnaires in Tanzania. The instrument was found to have acceptable psychometric properties, resulting in a new useful tool for medical and social research in this setting.

Cross-Cultural Adaptation and Psychometric Properties of the AUDIT and CAGE Questionnaires in Tanzanian Swahili for a Traumatic Brain Injury Population.

AIMS: To develop Swahili versions of the Alcohol Use Disorders Identification Test (AUDIT) and CAGE questionnaires and evaluate their psychometric properties in a traumatic brain injury (TBI) population in Tanzania. METHODS: Swahili versions of the AUDIT and CAGE were developed through translation and back-translation by a panel of native speakers of both English and Swahili. The translated instruments were administered to a sample of Tanzanian adults from a TBI registry. The validity and reliability were analyzed using standard statistical methods. RESULTS: The translated versions of both the AUDIT and CAGE questionnaires were found to have excellent language clarity and domain coherence. Reliability was acceptable (>0.85) for all tested versions. Confirmatory factor analysis of one, two and three factor solution for the AUDIT and one factor solution for the CAGE showed adequate results. AUDIT and CAGE scores were strongly correlated to each other (R > 0.80), and AUDIT scores were significantly lower in non-drinkers compared to drinkers. CONCLUSIONS: This article presents the first Swahili and Tanzanian adaptations of the AUDIT and CAGE instruments as well as the first validation of these questionnaires with TBI patients. Both instruments were found to have acceptable psychometric properties, resulting in two new useful tools for medical and social research in this setting.

c-Jun integrates signals from both MEK/ERK and MKK/JNK pathways upon vaccinia virus infection.

Usurpation of the host's signalling pathways is a common strategy employed by viruses to promote their successful replication. Here we show that infection with the orthopoxvirus vaccinia virus (VACV) leads to sustained stimulation of c-Jun activity during the entire infective cycle. This stimulation is temporally regulated through MEK/ERK or MKK/JNK pathways, i.e. during the early/mid phase (1 to 6 hpi) and in the late phase (9 to 24 hpi) of the infective cycle, respectively. As a transcriptional regulator, upon infection with VACV, c-Jun is translocated from the cytoplasm to the nucleus, where it binds to the AP-1 DNA sequence found at the promoter region of its target genes. To investigate the role played by c-Jun during VACV replication cycle, we generated cell lines that stably express a c-Jun-dominant negative (DNc-Jun) mutation. Our data revealed that c-Jun is required during early infection to assist with viral DNA replication, as demonstrated by the decreased amount of viral DNA found in the DNc-Jun cells. We also demonstrated that c-Jun regulates the expression of the early growth response gene (egr-1), a gene previously shown to affect VACV replication mediated by MEK/ERK signalling. VACV-induced stimulation of the MKK/JNK/JUN pathway impacts viral dissemination, as we observed a significant reduction in both viral yield, during late stages of infection, and virus plaque size. Collectively, our data suggest that, by modulating the host's signalling pathways through a common target such as c-Jun, VACV temporally regulates its infective cycle in order to successfully replicate and subsequently spread.

Plasmin induces in vivo monocyte recruitment through protease-activated receptor-1-, MEK/ERK-, and CCR2-mediated signaling.

The plasminogen (Plg)/plasmin (Pla) system is associated with a variety of biological activities beyond the classical dissolution of fibrin clots, including cell migration, tissue repair, and inflammation. Although the capacity of Plg/Pla to induce cell migration is well defined, the mechanism underlying this process in vivo is elusive. In this study, we show that Pla induces in vitro migration of murine fibroblasts and macrophages (RAW 264.7) dependent on the MEK/ERK pathway and by requiring its proteolytic activity and lysine binding sites. Plasmin injection into the pleural cavity of BALB/c mice induced a time-dependent influx of mononuclear cells that was associated with augmented ERK1/2 and IκB-α phosphorylation and increased levels of CCL2 and IL-6 in pleural exudates. The inhibition of protease activity by using a serine protease inhibitor leupeptin or two structurally different protease-activated receptor-1 antagonists (SCH79797 and RWJ56110) abolished Pla-induced mononuclear recruitment and ERK1/2 and IκB-α phosphorylation. Interestingly, inhibition of the MEK/ERK pathway abolished Pla-induced CCL2 upregulation and mononuclear cell influx. In agreement with a requirement for the CCL2/CCR2 axis to Pla-induced cell migration, the use of a CCR2 antagonist (RS504393) prevented the Plg/Pla-induced recruitment of mononuclear cells to the pleural cavity and migration of macrophages at transwell plates. Therefore, Pla-induced mononuclear cell recruitment in vivo was dependent on protease-activated receptor-1 activation of the MEK/ERK/NF-κB pathway, which led to the release of CCL2 and activation of CCR2.

Consuming viscous prey: a novel protein-secreting delivery system in neotropical snail-eating snakes.

BACKGROUND: Efficient venom delivery systems are known to occur only in varanoid lizards and advanced colubroidean snakes among squamate reptiles. Although components of these venomous systems might have been present in a common ancestor, the two lineages independently evolved strikingly different venom gland systems. In snakes, venom is produced exclusively by serous glands in the upper jaw. Within the colubroidean radiation, lower jaw seromucous infralabial glands are known only in two distinct lineages-the basal pareatids and the more advanced Neotropical dipsadines known as "goo-eating snakes". Goo-eaters are a highly diversified, ecologically specialized clade that feeds exclusively on invertebrates (e.g., gastropod molluscs and annelids). Their evolutionary success has been attributed to their peculiar feeding strategies, which remain surprisingly poorly understood. More specifically, it has long been thought that the more derived Dipsadini genera Dipsas and Sibynomorphus use glandular toxins secreted by their infralabial glands to extract snails from their shells. RESULTS: Here, we report the presence in the tribe Dipsadini of a novel lower jaw protein-secreting delivery system effected by a gland that is not functionally related to adjacent teeth, but rather opens loosely on the oral epithelium near the tip of the mandible, suggesting that its secretion is not injected into the prey as a form of envenomation but rather helps control the mucus and assists in the ingestion of their highly viscous preys. A similar protein-secreting system is also present in the goo-eating genus Geophis and may share the same adaptive purpose as that hypothesized for Dipsadini. Our phylogenetic hypothesis suggests that the acquisition of a seromucous infralabial gland represents a uniquely derived trait of the goo-eating clade that evolved independently twice within the group as a functionally complex protein-secreting delivery system. CONCLUSIONS: The acquisition by snail-eating snakes of such a complex protein-secreting system suggests that the secretion from the hypertrophied infralabial glands of goo-eating snakes may have a fundamental role in mucus control and prey transport rather than envenomation of prey. Evolution of a functional secretory system that combines a solution for mucus control and transport of viscous preys is here thought to underlie the successful radiation of goo-eating snakes.

Antibacterial and Antiviral Properties of Chenopodin-Derived Synthetic Peptides.

Antimicrobial peptides have been developed based on plant-derived molecular scaffolds for the treatment of infectious diseases. Chenopodin is an abundant seed storage protein in quinoa, an Andean plant with high nutritional and therapeutic properties. Here, we used computer- and physicochemical-based strategies and designed four peptides derived from the primary structure of Chenopodin. Two peptides reproduce natural fragments of 14 amino acids from Chenopodin, named Chen1 and Chen2, and two engineered peptides of the same length were designed based on the Chen1 sequence. The two amino acids of Chen1 containing amide side chains were replaced by arginine (ChenR) or tryptophan (ChenW) to generate engineered cationic and hydrophobic peptides. The evaluation of these 14-mer peptides on Staphylococcus aureus and Escherichia coli showed that Chen1 does not have antibacterial activity up to 512 µM against these strains, while other peptides exhibited antibacterial effects at lower concentrations. The chemical substitutions of glutamine and asparagine by amino acids with cationic or aromatic side chains significantly favoured their antibacterial effects. These peptides did not show significant hemolytic activity. The fluorescence microscopy analysis highlighted the membranolytic nature of Chenopodin-derived peptides. Using molecular dynamic simulations, we found that a pore is formed when multiple peptides are assembled in the membrane. Whereas, some of them form secondary structures when interacting with the membrane, allowing water translocations during the simulations. Finally, Chen2 and ChenR significantly reduced SARS-CoV-2 infection. These findings demonstrate that Chenopodin is a highly useful template for the design, engineering, and manufacturing of non-toxic, antibacterial, and antiviral peptides.

New anti-SARS-CoV-2 aminoadamantane compounds as antiviral candidates for the treatment of COVID-19.

Here, the antiviral activity of aminoadamantane derivatives were evaluated against SARS-CoV-2. The compounds exhibited low cytotoxicity to Vero, HEK293 and CALU-3 cells up to a concentration of 1,000 µM. The inhibitory concentration (IC50) of aminoadamantane was 39.71 µM in Vero CCL-81 cells and the derivatives showed significantly lower IC50 values, especially for compounds 3F4 (0.32 µM), 3F5 (0.44 µM) and 3E10 (1.28 µM). Additionally, derivatives 3F5 and 3E10 statistically reduced the fluorescence intensity of SARS-CoV-2 protein S from Vero cells at 10 µM. Transmission microscopy confirmed the antiviral activity of the compounds, which reduced cytopathic effects induced by the virus, such as vacuolization, cytoplasmic projections, and the presence of myelin figures derived from cellular activation in the face of infection. Additionally, it was possible to observe a reduction of viral particles adhered to the cell membrane and inside several viral factories, especially after treatment with 3F4. Moreover, although docking analysis showed favorable interactions in the catalytic site of Cathepsin L, the enzymatic activity of this enzyme was not inhibited significantly in vitro. The new derivatives displayed lower predicted toxicities than aminoadamantane, which was observed for either rat or mouse models. Lastly, in vivo antiviral assays of aminoadamantane derivatives in BALB/cJ mice after challenge with the mouse-adapted strain of SARS-CoV-2, corroborated the robust antiviral activity of 3F4 derivative, which was higher than aminoadamantane and its other derivatives. Therefore, aminoadamantane derivatives show potential broad-spectrum antiviral activity, which may contribute to COVID-19 treatment in the face of emerging and re-emerging SARS-CoV-2 variants of concern.