The Possible Role of Microbial Proteases in Facilitating SARS-CoV-2 Brain Invasion

SARS-CoV-2 has been shown to display proclivity towards organs bearing angiotensin-converting enzyme (ACE2) expression cells. Of interest herein is the ability of the virus to exhibit neurotropism. However, there is limited information on how this virus invades the brain. With this contribution, we explore how, in the context of a microbial co-infection using a cryptococcal co-infection as a model, SARS-CoV-2 could reach the brain. We theorise that the secretion of proteases by disseminated fungal cells might also activate the S2 domain of the viral spike glycoprotein for membrane fusion with brain endothelial cells leading to endocytosis. Understanding this potential invasion mechanism could lead to better SARS-CoV-2 intervention measures, which may also be applicable in instances of co-infection, especially with protease-secreting pathogens.

Bovine Parainfluenza Virus Type 3 (BPIV3) Enters HeLa Cells via Clathrin-Mediated Endocytosis in a Cholesterol- and Dynamin-Dependent Manner

Bovine parainfluenza virus 3 (BPIV3) is a crucial causative agent of respiratory disease in young and adult cattle. No specific therapies are available for BPIV3 infection. Understanding the internalization pathway of the virus will provide a new strategy for the development of antiviral therapy. Here, the mechanism of BPIV3 entry into HeLa cells was analyzed using RNA silencing and pharmacological inhibitors. Treatment of HeLa cells with hypertonic medium prevented BPIV3 internalization. These results indicated that BPIV3 entered HeLa cells via receptor-mediated endocytosis. Moreover, removing cell membrane cholesterol through MβCD treatment hampered viral penetration but not viral replication. In addition, BPIV3 infection was inhibited by pretreatment with dynasore or chlorpromazine (CPZ) or knockdown of dynamin II or clathrin heavy chain. However, virus entry was unaffected by nystatin, EIPA, wortmannin, or cytochalasin D treatment or caveolin-1 knockdown. These data demonstrated that the entry of BPIV3 into HeLa cells was dependent on clathrin-mediated endocytosis but not on caveolae-mediated endocytosis or the macropinocytosis pathway. Many viruses are transported to endosomes, which provide an acidic environment and release their genome upon separation from primary endocytic vesicles. However, we found that BPIV3 infection required endosomal cathepsins, but not a low pH. In summary, we show, for the first time, that BPIV3 enters HeLa cells through the clathrin-mediated endocytosis pathway, presenting novel insights into the invasion mechanism of Paramyxoviridae.

Long Noncoding RNA LINC00526 Represses Glioma Progression via Regulating miR-5581-3p/BEX1

The roles of long noncoding RNAs (lncRNAs) in regulating glioma progression have been widely recognized in recent years. This work was to investigate the roles and associated mechanisms of LINC00526 in glioma progression. LINC00526 expression in glioma tissues and cells and their normal counterparts was measured with quantitative real-time polymerase chain reaction method. Functions of LINC00526 in glioma were investigated with in vitro experiments. Moreover, competitive RNA (ceRNA) theory was employed to understand mechanisms of action of LINC00526 in glioma. LINC00526 was found to be decreased in glioma tissues and cell lines compared with their normal counterparts. Silencing the expression of LINC00526 promotes, while forcing its expression, inhibits glioma cell growth and invasion. Mechanism analyses showed LINC00526 functions as a sponge for microRNA-5581-3p (miR-5581-3p) to regulate brain-expressed X-linked 1 (BEX1) expression and, in the end, affects glioma progression. Collectively, our study indicated LINC00526 serves as a tumor-suppressive lncRNA and directly regulates miR-5581-3p/BEX1 axis in glioma.

Research Progress on Growth Characteristics of Invasive Plants in Different Habitats

Biological invasion generates serious threats to global biodiversity. Exotic species usually have high environmental adaptability and tolerance, which is one of the bases of their invasion. Except for biological invasion threats, other serious environmental problems like extreme cold or hot events, soil drought, saline-alkali and flood are emerging constantly on a global scale. In the background of multiple environmental problems interfering with existing habitats, exploring the growth characteristics of invasive plants in different habitats, and grasping the reasons why the invasive plants can obtain growth superiorities are in favor of propelling the understanding of their invasion mechanism. This paper gives an overview of research progress on the invasive plants’ morphological characteristics and physiological characteristics in deferent habitats, summarizes the growth specialties of invasive plants which are affected by high temperature, low temperature, drought and flood, and discusses the reasons why the invasive plants prevail in the growth competitions, which provided theoretical and realistic signification to relieve the biological invasion current status.

Viral Pandemics of the Last Four Decades: Pathophysiology, Health Impacts and Perspectives

The last four decades has witnessed some of the deadliest viral pandemics with far-reaching consequences. These include the Human Immunodeficiency Virus (HIV) (1981), Severe Acute Respiratory Syndrome Coronavirus (SARS-CoV) (2002), Influenza A virus subtype H1N1 (A/H1N1) (2009), Middle East Respiratory Syndrome Coronavirus (MERS-CoV) (2012), Ebola virus (2013) and the Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) (2019-present). Age- and gender-based characterizations suggest that SARS-CoV-2 resembles SARS-CoV and MERS-CoV with regard to higher fatality rates in males, and in the older population with comorbidities. The invasion-mechanism of SARS-CoV-2 and SARS-CoV, involves binding of its spike protein with angiotensin-converting enzyme 2 (ACE2) receptors; MERS-CoV utilizes dipeptidyl peptidase 4 (DPP4), whereas H1N1 influenza is equipped with hemagglutinin protein. The viral infections-mediated immunomodulation, and progressive inflammatory state may affect the functions of several other organs. Although no effective commercial vaccine is available for any of the viruses, those against SARS-CoV-2 are being developed at an unprecedented speed. Until now, only Pfizer/BioNTech’s vaccine has received temporary authorization from the UK Medicines and Healthcare products Regulatory Agency. Given the frequent emergence of viral pandemics in the 21st century, proper understanding of their characteristics and modes of action are essential to address the immediate and long-term health consequences.

Screening and Verification of Host Proteins Interacting with Neospora Caninum AMA1 Using a Yeast Two-hybrid System

Background: Neospora caninum apical membrane antigen 1 (NcAMA1) is a conservative type I transmembrane protein that is secreted by the microneme to the surface of the parasite, and is a key component of the invasion mechanism. In order to explore further the biological functions of NcAMA1 in the process of parasite invasion, we conducted research on NcAMA1 and its interacting partners. Methods: In this study, Vero cell yeast two-hybrid (Y2H) cDNA library was constructed. Using the constructed recombinant vector pGBKT7-NcAMA1 as bait, the Y2H system was used to screen the proteins that interact with NcAMA1. In addition, the interaction between NcAMA1 and the screened transmembrane emp24 domain trafficking protein 2 （Tmed2）was further verified by one-to-one Y2H experiments and pull-down, and the role of Tmed2 protein in the process of N. caninum invasion was initially verified by RNA silencing and antibody blocking experiments.Results: Our results show that, through the Y2H experiment, we have identified two proteins that interact with NcAMA1, which are the Chlorocebus sabaeus filamin A, alpha and Chlorocebus sabaeus Tmed2. When the expression of Tmed2 protein decreased or blocked, the invasion rate of N. caninum was increased.Conclusions: These findings give us a deeper understanding of the biological functions of NcAMA1, and for the first time suggest that Tmed2 may be involved in the process invasion by of N. caninum, inhibiting the invasion of parasites by interacting with the protein secreted by N. caninum.

The Effect of Temperature on Seed Germination and Seedling Growth of Two Invasive Plants in Rorippa

Aims: By studying the response of seed germination and seedling growth of invasive plants, Rorippa amphibia and Rorippa sylvestris, to temperature, the influence of temperature on the invasive ability of two species of Rorippa were further analyzed, which provided a theoretical basis for revealing the diffusion and invasion mechanism of two invasive plants in Rorippa. Study Design: Seed germination and seedling growth test of two invasive plants in Rorippa at different temperature was studied by means of laboratory culture. The germination percentage, germination index, germination potential of the seeds and the total leaf number, root length, lateral root number, biomass and root shoot ratio of seedlings were determined. Place and Duration of Study: Seeds were collected from the Shenyang Agricultural University of Liaoning Province in July 2018. Experiments were done in the College of Bioscience and Biotechnology, and conducted in April 2019 for a month. Methodology: The petri dish method was used at the experiment of seed germination. The seedling growth experiment was carried out by pot sowing. Results: At the seedling stage.R. amphibia has the strongest tolerance at 30°C, while the R. sylvestris does at 35°C. The low temperature is more beneficial to the accumulations of the seedlings, R. amphibia is the most tolerant at 25°C, and R. sylvestris is at 30°C at the seedling stage. Conclusion: The response of the seeds and seedlings of the two species to temperature was basically the same. Higher temperature promoted seed germination and inhibited seedling growth, while lower temperature inhibited seed germination. The response of seeds and seedlings of R. sylvestris to high temperature makes it more invasive in the process of global warming.

Early changes in bacterial communities in wound tissues of Pinus massoniana after inoculation with Bursaphelenchus xylophilus

Summary The bacterial communities in the wound tissues of Pinus massoniana were analysed by 16S rDNA amplicon sequencing. The results showed that the bacterial richness and diversity changed remarkably whether the wound was inoculated with pine wood nematode (PWN; Bursaphelenchus xylophilus) or not after 12 h. However, the predominant bacteria Stenotrophomonas, Burkholderiaceae, Pseudomonas, Serratia and Delftia, introduced by PWN in the wound tissues, changed within 6 h. After 6 h of PWN inoculation, the most abundant genus associating with PWN, Stenotrophomonas, failed to colonise the wound tissues, and the abundance of Delftia decreased, while the other representative bacteria, Burkholderiaceae, Pseudomonas and Serratia, from the PWN were markedly enriched. In addition, our study is the first to report the association of Serratia liquefaciens with PWN. Predicted functional analyses using the Tax4Fun tool showed that the alterations in bacterial composition also led to shifts in their functional pathways, especially after 12 h of PWN inoculation. These findings clarified that the bacteria carried by PWN were responsible for the alterations in bacterial communities in the wound tissues and will shed light on the invasion mechanism of PWN.