Widespread circulation of SARS-CoV-2 in humans raises the theoretical risk of reverse zoonosis events with wildlife, reintroductions of SARS-CoV-2 into permissive nondomesticated animals. Here we ...report that North American deer mice (Peromyscus maniculatus) are susceptible to SARS-CoV-2 infection following intranasal exposure to a human isolate, resulting in viral replication in the upper and lower respiratory tract with little or no signs of disease. Further, shed infectious virus is detectable in nasal washes, oropharyngeal and rectal swabs, and viral RNA is detectable in feces and occasionally urine. We further show that deer mice are capable of transmitting SARS-CoV-2 to naïve deer mice through direct contact. The extent to which these observations may translate to wild deer mouse populations remains unclear, and the risk of reverse zoonosis and/or the potential for the establishment of Peromyscus rodents as a North American reservoir for SARS-CoV-2 remains unknown.
The 2013-2016 Ebola virus (EBOV) disease epidemic demonstrated the grave consequences of filovirus epidemics in the absence of effective therapeutics. Besides EBOV, two additional ebolaviruses, Sudan ...(SUDV) and Bundibugyo (BDBV) viruses, as well as multiple variants of Marburg virus (MARV), have also caused high fatality epidemics. Current experimental EBOV monoclonal antibodies (mAbs) are ineffective against SUDV, BDBV, or MARV. Here, we report that a cocktail of two broadly neutralizing ebolavirus mAbs, FVM04 and CA45, protects nonhuman primates (NHPs) against EBOV and SUDV infection when delivered four days post infection. This cocktail when supplemented by the anti-MARV mAb MR191 exhibited 100% efficacy in MARV-infected NHPs. These findings provide a solid foundation for clinical development of broadly protective immunotherapeutics for use in future filovirus epidemics.
Computational approaches for drug discovery, such as quantitative structure-activity relationship, rely on structural similarities of small molecules to infer biological activity but are often ...limited to identifying new drug candidates in the chemical spaces close to known ligands. Here we report a biological activity-based modeling (BABM) approach, in which compound activity profiles established across multiple assays are used as signatures to predict compound activity in other assays or against a new target. This approach was validated by identifying candidate antivirals for Zika and Ebola viruses based on high-throughput screening data. BABM models were then applied to predict 311 compounds with potential activity against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Of the predicted compounds, 32% had antiviral activity in a cell culture live virus assay, the most potent compounds showing a half-maximal inhibitory concentration in the nanomolar range. Most of the confirmed anti-SARS-CoV-2 compounds were found to be viral entry inhibitors and/or autophagy modulators. The confirmed compounds have the potential to be further developed into anti-SARS-CoV-2 therapies.
Experimental monoclonal antibody (mAb) therapies have shown promise for treatment of lethal Ebola virus (EBOV) infections, but their species-specific recognition of the viral glycoprotein (GP) has ...limited their use against other divergent ebolaviruses associated with human disease. Here, we mined the human immune response to natural EBOV infection and identified mAbs with exceptionally potent pan-ebolavirus neutralizing activity and protective efficacy against three virulent ebolaviruses. These mAbs recognize an inter-protomer epitope in the GP fusion loop, a critical and conserved element of the viral membrane fusion machinery, and neutralize viral entry by targeting a proteolytically primed, fusion-competent GP intermediate (GPCL) generated in host cell endosomes. Only a few somatic hypermutations are required for broad antiviral activity, and germline-approximating variants display enhanced GPCL recognition, suggesting that such antibodies could be elicited more efficiently with suitably optimized GP immunogens. Our findings inform the development of both broadly effective immunotherapeutics and vaccines against filoviruses.
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•The human humoral response to Ebola virus contains broadly neutralizing antibodies•Potent pan-ebolavirus neutralizing antibodies recognize the viral fusion loop•The antibodies target viral entry intermediate generated in endosomes•The antibodies protect against three ebolaviruses that cause outbreaks in humans
Characterization of human broadly neutralizing antibodies active against all five species of ebolaviruses highlights the fusion loop region of the viral glycoprotein as a promising vaccine target.
The long-term storage of coal gangue (CG) mountains causes serious environmental problems such as water and air pollution. Thus, sustainable reclamation practices are urgently needed to minimize the ...environmental impacts brought by CG mountains. Pikovskaya medium was employed to screen microorganisms, which were subsequently utilized to promote the solubilization of CG. XRF, SEM, XRD, and HPLC techniques were employed to characterize the CG before and after bacterial treatment. In this study, we have successfully isolated and purified a bacterial strain, identified as Stenotrophomonas bentonitica BII-R7, which possesses the ability to facilitate the solubilization of nutrient elements from CG. Factors including initial inoculation ratio, incubation time, CG particle size, CG concentration, pH, and temperature were examined to investigate their effects on the biosolubilization of CG. Furthermore, the mechanism underlying the CG solubilization was also probed. Our data demonstrated that low-molecular-weight organic acids, such as acetic acid and formic acid, may harbor a crucial role in promoting the solubilization of CG. Lastly, we found that Stenotrophomonas bentonitica BII-R7, in conjugation with CG, can increase the alfalfa seed germination percentage and promote the growth of alfalfa. Together, these data provide evidence that bacterial-treated CG can be utilized for soil improvement and land reclamation.
Dear Editor, The 2015-2016 outbreak of Zika virus （ZIKV） fever, first reported in Brazil during early 2015 （Zanluca et al., 2015）, has infected millions of people and is a global public health ...concern. ZIKV infections are associated with fetal microcephaly, as well as neurological complications in humans. The virus can be shed in the semen and vaginal secretions of humans, leading to sexual transmission, and unexpectedly ZIKV infections cause severe damage to the male reproductive organs in male mice （Govero et al., 2016; Ma et al., 2016）.
The reproduction and survival of fish are often negatively affected by the construction of dams and other hydroelectric projects, which cut off their migratory routes. Building effective fish passage ...facilities that allow fish to pass through dams smoothly alleviates the negative impact of hydroelectric projects on the ecological environment, thus protecting the diversity of aquatic species and preventing the extinction of indigenous fish. Vertical slit fishways are highly effective, but turbulence inside the fishway pools directly affects fish passage. In this study, the large-eddy simulation framework is used to capture the vortex characteristics in the interior of vertical slit fishway pools, and the volume of fluid method is applied to simulate the free surface. The independence of the grid is assessed by the large-eddy simulation quality index, and the simulation results are compared with experimental acoustic Doppler velocimetry data. This work characterizes the vortex flow field inside the vertical slit fishway using the Q-criterion, Omega method, and Liutex vortex identification method. The results show that the vortex structure inside the fishway pool has obvious three-dimensional characteristics and vortex structure varies within the different fishway pool chambers. The analysis and comparison of the three different vortex identification methods show that the vortex structure captured by the Liutex method is more consistent with the actual motion pattern of the fishway water flow.
Several in silico studies have determined that quercetin, a plant flavonol, could bind with strong affinity and low free energy to SARS-CoV-2 proteins involved in viral entry and replication, ...suggesting it could block infection of human cells by the virus. In the present study, we examined the ex vivo ability of quercetin to inhibit of SARS-CoV-2 replication and explored the mechanisms of this inhibition.
Green monkey kidney Vero E6 cells and in human colon carcinoma Caco-2 cells were infected with SARS-CoV-2 and incubated in presence of quercetin; the amount of replicated viral RNA was measured in spent media by RT-qPCR. Since the formation of syncytia is a mechanism of SARS-CoV-2 propagation, a syncytialization model was set up using human embryonic kidney HEK293 co-expressing SARS-CoV-2 Spike (S) protein and human angiotensin converting enzyme 2 (ACE2), HEK293(S + ACE2) cells, to assess the effect of quercetin on this cytopathic event by microscopic imaging and protein immunoblotting.
Quercetin inhibited SARS-CoV-2 replication in Vero E6 cells and Caco-2 cells in a concentration-dependent manner with a half inhibitory concentration (IC
) of 166.6 and 145.2 µM, respectively. It also inhibited syncytialization of HEK293(S + ACE2) cells with an IC
of 156.7 µM. Spike and ACE2 co-expression was associated with decreased expression, increased proteolytic processing of the S protein, and diminished production of the fusogenic S2' fragment of S. Furin, a proposed protease for this processing, was inhibited by quercetin in vitro with an IC
of 116 µM.
These findings suggest that at low 3-digit micromolar concentrations of quercetin could impair SARS-CoV-2 infection of human cells partly by blocking the fusion process that promotes its propagation.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Sequencing of Ebola virus (EBOV) genomes during the 2014-2016 epidemic identified several naturally occurring, dominant mutations potentially impacting virulence or tropism. In this study, we ...characterized EBOV variants carrying one of the following substitutions: A82V in the glycoprotein (GP), R111C in the nucleoprotein (NP), or D759G in the RNA-dependent RNA polymerase (L). Compared with the wild-type (WT) EBOV C07 isolate, NP and L mutants conferred a replication advantage in monkey Vero E6, human A549, and insectivorous bat Tb1.Lu cells, while L mutants displayed a disadvantage in human Huh7 cells. The replication of the GP mutant was significantly delayed in Tb1.Lu cells and similar to that of the WT in other cells. The L mutant was less virulent, as evidenced by increased survival for mice and a significantly delayed time to death for ferrets, but increased lengths of the period of EBOV shedding may have contributed to the prolonged epidemic. Our results show that single substitutions can have observable impacts on EBOV pathogenicity and provide a framework for the study of other mutations.
During the Ebola virus (EBOV) disease outbreak in West Africa in 2014-2016, it was discovered that several mutations in the virus emerged and became prevalent in the human population. This suggests that these mutations may play a role impacting viral fitness. We investigated three of these previously identified mutations (in the glycoprotein GP, nucleoprotein NP, or RNA-dependent RNA polymerase L) in cell culture, as well as in mice and ferrets, by generating recombinant viruses (based on an early West African EBOV strain) each carrying one of these mutations. The NP and L mutations appear to decrease virulence, whereas the GP mutation slightly increases virulence but mainly impacts viral tropism. Our results show that these single mutations can impact EBOV virulence in animals and have implications for the rational design of efficacious antiviral therapies against these infections.
Although a group of FDA-approved drugs were previously identified with activity against Ebola virus (EBOV), most of them are not clinically useful because their human blood concentrations are not ...high enough to inhibit EBOV infection. We screened 795 unique three-drug combinations in an EBOV entry assay. Two sets of three-drug combinations, toremifene-mefloquine-posaconazole and toremifene-clarithromycin-posaconazole, were identified that effectively blocked EBOV entry and were further validated for inhibition of live EBOV infection. The individual drug concentrations in the combinations were reduced to clinically relevant levels. We identified mechanisms of action of these drugs: functional inhibitions of Niemann–Pick C1, acid sphingomyelinase, and lysosomal calcium release. Our findings identify the drug combinations with potential to treat EBOV infection.
•Drug combinations may enable clinical application by reducing individual drug concentrations for inhibiting EBOV infection.•795 pairs of three-drug combinations of FDA-approved drugs were screened for anti-Ebola virus activity.•Two sets of clinical useful three-drug combinations were validated for inhibition of live Ebola virus infection.•Mechanisms of action of these drugs were identified in affecting host-pathogen interactions.
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