The role of microbial loop in the ecology of the ocean

Mikrobna petlja ima neizostavnu ulogu u kruženju tvari u oceanu i zbog abundantnosti i rasprostranjenosti mikroorganizama efikasnost hranidbene mreže uvelike ovisi o njoj. Ne samo u oceanu, nego mikrobna petlja ima veliki utjecaj i globalno, otpuštanjem DMS-a u atmosferu i stvaranjem oblaka te kao mikrobna pumpa i skladištenje ugljika u oceanu kao RDOC. Ona se smatra kao jedno od mogućih rješenja problema globalnog zatopljenja. Nastanak RDOC u oceanu nije još sasvim jasan te su potrebna dodatna istraživanja. Zbog svojeg velikog utjecaja, mikrobna petlja bi se trebala proučavati mikroskopski koliko i makroskopski. Osim toga interakcije između fitoplanktona i mikrobne petlje su puno kompleksnije nego se prvotno smatralo te određuju cijelu hranidbenu mrežu ekosustava.Microbial loop has an inescapable role in circulation of elements in the ocean and because of the abundance and distribution of microorganisms the efficiency of the food web greatly depends on it. Not only in the ocean, but microbial loop has a big impact globally with the release of DMS in the atmosphere and clouds formation and as microbial carbon pump and storage of carbon in the ocean as RDOC. It is considered to be one of the possible solutions to global warming. The creation of RDOC in the ocean is not yet fully clear and further research is needed. Because of its great impact, microbial loop should be studied both microscopically as well as macroscopically. Furthermore, interactions between phytoplankton and the microbial loop are far more complex than previously thought and can determine the entire food web of the ecosystem

The role of microbial loop in the ecology of the ocean

Mikrobna petlja ima neizostavnu ulogu u kruženju tvari u oceanu i zbog abundantnosti i rasprostranjenosti mikroorganizama efikasnost hranidbene mreže uvelike ovisi o njoj. Ne samo u oceanu, nego mikrobna petlja ima veliki utjecaj i globalno, otpuštanjem DMS-a u atmosferu i stvaranjem oblaka te kao mikrobna pumpa i skladištenje ugljika u oceanu kao RDOC. Ona se smatra kao jedno od mogućih rješenja problema globalnog zatopljenja. Nastanak RDOC u oceanu nije još sasvim jasan te su potrebna dodatna istraživanja. Zbog svojeg velikog utjecaja, mikrobna petlja bi se trebala proučavati mikroskopski koliko i makroskopski. Osim toga interakcije između fitoplanktona i mikrobne petlje su puno kompleksnije nego se prvotno smatralo te određuju cijelu hranidbenu mrežu ekosustava.Microbial loop has an inescapable role in circulation of elements in the ocean and because of the abundance and distribution of microorganisms the efficiency of the food web greatly depends on it. Not only in the ocean, but microbial loop has a big impact globally with the release of DMS in the atmosphere and clouds formation and as microbial carbon pump and storage of carbon in the ocean as RDOC. It is considered to be one of the possible solutions to global warming. The creation of RDOC in the ocean is not yet fully clear and further research is needed. Because of its great impact, microbial loop should be studied both microscopically as well as macroscopically. Furthermore, interactions between phytoplankton and the microbial loop are far more complex than previously thought and can determine the entire food web of the ecosystem

The role of microbial loop in the ecology of the ocean

Mikrobna petlja ima neizostavnu ulogu u kruženju tvari u oceanu i zbog abundantnosti i rasprostranjenosti mikroorganizama efikasnost hranidbene mreže uvelike ovisi o njoj. Ne samo u oceanu, nego mikrobna petlja ima veliki utjecaj i globalno, otpuštanjem DMS-a u atmosferu i stvaranjem oblaka te kao mikrobna pumpa i skladištenje ugljika u oceanu kao RDOC. Ona se smatra kao jedno od mogućih rješenja problema globalnog zatopljenja. Nastanak RDOC u oceanu nije još sasvim jasan te su potrebna dodatna istraživanja. Zbog svojeg velikog utjecaja, mikrobna petlja bi se trebala proučavati mikroskopski koliko i makroskopski. Osim toga interakcije između fitoplanktona i mikrobne petlje su puno kompleksnije nego se prvotno smatralo te određuju cijelu hranidbenu mrežu ekosustava.Microbial loop has an inescapable role in circulation of elements in the ocean and because of the abundance and distribution of microorganisms the efficiency of the food web greatly depends on it. Not only in the ocean, but microbial loop has a big impact globally with the release of DMS in the atmosphere and clouds formation and as microbial carbon pump and storage of carbon in the ocean as RDOC. It is considered to be one of the possible solutions to global warming. The creation of RDOC in the ocean is not yet fully clear and further research is needed. Because of its great impact, microbial loop should be studied both microscopically as well as macroscopically. Furthermore, interactions between phytoplankton and the microbial loop are far more complex than previously thought and can determine the entire food web of the ecosystem

Structural Studies Reveal that Endosomal Cations Promote Formation of Infectious Coxsackievirus A9 A-Particles, Facilitating RNA and VP4 Release

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SARS-CoV-2 Production, Purification Methods and UV Inactivation for Proteomics and Structural Studies

Severe acute respiratory syndrome coronavirus-2 is the causative agent of COVID-19. During the pandemic of 2019–2022, at least 500 million have been infected and over 6.3 million people have died from COVID-19. The virus is pleomorphic, and due to its pathogenicity is often handled in very restrictive biosafety containments laboratories. We developed two effective and rapid purification methods followed by UV inactivation that allow easy downstream handling of the virus. We monitored the purification through titering, sequencing, mass spectrometry and electron cryogenic microscopy. Although pelleting through a sucrose cushion, followed by gentle resuspension overnight gave the best particle recovery, infectivity decreased, and the purity was significantly worse than if using the size exclusion resin Capto Core. Capto Core can be used in batch mode, and was seven times faster than the pelleting method, obviating the need for ultracentrifugation in the containment laboratory, but resulting in a dilute virus. UV inactivation was readily optimized to allow handling of the inactivated samples under standard operating conditions. When containment laboratory space is limited, we recommend the use of Capto Core for purification and UV for inactivation as a simple, rapid workflow prior, for instance, to electron cryogenic microscopy or cell activation experiments

Investigation of antiviral activity of posaconazole against Parechoviruses

OBJECTIVES and RESEARCH QUESTION. Human parechovirus 3 (HPeV3) is a (+)ssRNA icosahaedrally symmetric virus which causes meningoencephalitis and sepsis in children and neonates. As it causes the most severe symptoms among parechoviruses it is attracting more attention (4). Currently there are no approved broad treatment strategies against parechoviruses, however recent research by Rhoden et al., 2017, reported the antiviral activity of posaconazole (PSZ) against HPeV3 in cell culture. Posaconazole is an antifungal drug approved for use against Candida and Aspergillus infections. It targets lanosterol-14alpha-demethylase and prevents the production of ergosterol, a lipid vital for fungal membranes not present in mammalian cells (24). In mammalian cells PSZ accumulates at the endoplasmic reticulum (ER) and binds to the oxysterol-binding protein (OSBP) and Niemann-pick type C1 (NPC1) (59, 28, 30). The drug may affect cellular components and thusly block parechoviral infection or could bind to the viral capsid. METHODS. To test viral capsid-binding hypothesis PSZ activity was tested in a range of concentrations against two HPeV3 isolates and HPeV1 Harris in Vero and HT29 cell lines. HPeV3 isolate 152037 was purified on a CsCl step gradient and imaged by cryo electron microscopy (cryo-EM). Single particle analysis was done in Scipion (40) and acquired density maps visualized in UCSF Chimera (49). Atomic model of a different isolate of HPeV3 (PDB ID: 6GV4, 16) was changed at 6 sites and fitted to density maps from this work in Coot (52). Maps were subtracted in search of density that would represent PSZ. RESULTS. PSZ was effective against both HPeV3 isolates at 1 μM in Vero cells when added to the virus prior to infection, however not in HT29 cells. At higher concentrations (>10 μM) PSZ formed crystals which limited the concentration that can be used for cryo-EM. In order to test the hypothesis of PSZ being a capsid binder 3 datasets were collected, HPeV3 control, HPeV3+DMSO and HPeV3+PSZ (4 μM) with final resolutions after single particle analysis of 3.3 Å, 3.9 Å and 3.4 Å respectively. Subtraction of maps yielded no difference that would represent PSZ. DISCUSSION and CONCLUSION. PSZ does not appear to be a capsid binder although it appears to work early in the infection. Absence of PSZ density in HPeV3+PSZ density map could be due to low saturation and images containing PSZ were filtered out in image processing. Another possibility is low affinity of PSZ for the capsid. As PSZ binds various membranes it is possible that it blocks HPeV3 infection by targeting cell components. Additional experiments could be performed in the future in order to provide insight into which stages of infection PSZ affects

SARS-CoV-2 Production, Purification Methods and UV Inactivation for Proteomics and Structural Studies

Severe acute respiratory syndrome coronavirus-2 is the causative agent of COVID-19. During the pandemic of 2019–2022, at least 500 million have been infected and over 6.3 million people have died from COVID-19. The virus is pleomorphic, and due to its pathogenicity is often handled in very restrictive biosafety containments laboratories. We developed two effective and rapid purification methods followed by UV inactivation that allow easy downstream handling of the virus. We monitored the purification through titering, sequencing, mass spectrometry and electron cryogenic microscopy. Although pelleting through a sucrose cushion, followed by gentle resuspension overnight gave the best particle recovery, infectivity decreased, and the purity was significantly worse than if using the size exclusion resin Capto Core. Capto Core can be used in batch mode, and was seven times faster than the pelleting method, obviating the need for ultracentrifugation in the containment laboratory, but resulting in a dilute virus. UV inactivation was readily optimized to allow handling of the inactivated samples under standard operating conditions. When containment laboratory space is limited, we recommend the use of Capto Core for purification and UV for inactivation as a simple, rapid workflow prior, for instance, to electron cryogenic microscopy or cell activation experiments

Antiviral action of a functionalized plastic surface against human coronaviruses

Viruses may persist on solid surfaces for long periods, which may contribute to indirect transmission. Thus, it is imperative to develop functionalized surfaces that will lower the infectious viral load in everyday life. Here, we have tested a plastic surface functionalized with tall oil rosin against the seasonal human coronavirus OC43 as well as severe acute respiratory syndrome coronavirus 2. All tested non-functionalized plastic surfaces showed virus persistence up to 48 h. In contrast, the functionalized plastic showed good antiviral action already within 15 min of contact and excellent efficacy after 30 min over 90% humidity. Excellent antiviral effects were also observed at lower humidities of 20% and 40%. Despite the hydrophilic nature of the functionalized plastic, viruses did not adhere strongly to it. According to helium ion microscopy, viruses appeared flatter on the rosin-functionalized surface, but after flushing away from the rosin-functionalized surface, they showed no apparent structural changes when imaged by transmission electron microscopy of cryogenic or negatively stained specimens or by atomic force microscopy. Flushed viruses were able to bind to their host cell surface and enter endosomes, suggesting that the fusion with the endosomal membrane was halted. The eluted rosin from the functionalized surface demonstrated its ability to inactivate viruses, indicating that the antiviral efficacy relied on the active leaching of the antiviral substances, which acted on the viruses coming into contact. The rosin-functionalized plastic thus serves as a promising candidate as an antiviral surface for enveloped viruses. IMPORTANCE During seasonal and viral outbreaks, the implementation of antiviral plastics can serve as a proactive strategy to limit the spread of viruses from contaminated surfaces, complementing existing hygiene practices. In this study, we show the efficacy of a rosin-functionalized plastic surface that kills the viral infectivity of human coronaviruses within 15 min of contact time, irrespective of the humidity levels. In contrast, non-functionalized plastic surfaces retain viral infectivity for an extended period of up to 48 h. The transient attachment on the surface or the leached active components do not cause major structural changes in the virus or prevent receptor binding; instead, they effectively block viral infection at the endosomal stage.Peer reviewe