Differential beta-coronavirus infection dynamics in human bronchial epithelial organoids.

The lower respiratory system serves as the target and barrier for beta-coronavirus (beta-CoV) infections. In this study, we explored beta-CoV infection dynamics in human bronchial epithelial (HBE) organoids, focusing on HCoV-OC43, SARS-CoV, MERS-CoV, and SARS-CoV-2. Utilizing advanced organoid culture techniques, we observed robust replication for all beta-CoVs, particularly noting that SARS-CoV-2 reached peak viral RNA levels at 72 h postinfection. Through comprehensive transcriptomic analysis, we identified significant shifts in cell population dynamics, marked by an increase in goblet cells and a concurrent decrease in ciliated cells. Furthermore, our cell tropism analysis unveiled distinct preferences in viral targeting: HCoV-OC43 predominantly infected club cells, while SARS-CoV had a dual tropism for goblet and ciliated cells. In contrast, SARS-CoV-2 primarily infected ciliated cells, and MERS-CoV showed a marked affinity for goblet cells. Host factor analysis revealed the upregulation of genes encoding viral receptors and proteases. Notably, HCoV-OC43 induced the unfolded protein response pathway, which may facilitate viral replication. Our study also reveals a complex interplay between inflammatory pathways and the suppression of interferon responses during beta-CoV infections. These findings provide insights into host-virus interactions and antiviral defense mechanisms, contributing to our understanding of beta-CoV infections in the respiratory tract.

Sub-micron microplastics affect nitrogen cycling by altering microbial abundance and activities in a soil-legume system.

Recently, the environmental and agricultural impact of plastic waste has attracted considerable attention. Here, we investigated the impact of sub-micron polyethylene (PE) and polypropylene (PP) microplastics (MPs) on nitrogen cycling, with emphasis on bacterial abundance and diversity in a soil-soybean (Glycine max) system. Exposure to soil containing MPs (50 and 500 mg kg-1) did not affect soybean growth, but significantly increased plant nitrogen uptake, which was confirmed by increased activities of nitrogenase in the soil and glutamine synthetase in soybean root. Additionally, there was an increase in 16S gene copy number and carbon and nitrogen substrate utilization, indicating increased abundance and activity of rhizosphere microbial communities. Moreover, MP contamination affected the taxonomic profile of rhizosphere bacteria, especially the abundance of symbiotic and free-living bacteria involved in nitrogen cycling. Furthermore, qPCR analysis of nitrogen-related genes and Kyoto Encyclopedia of Genes and Genomes analysis of 16S rRNA gene sequencing data revealed an increased abundance of functional genes associated with nitrogen fixation and nitrification. However, the concentration and polymer type of MPs did not have a significant impact in our system. Overall, these results provide insights into the interactions between MPs and rhizosphere bacterial communities in the soil-legume system.

Chronic effects of nano and microplastics on reproduction and development of marine copepod Tigriopus japonicus.

This study aimed to examine the impact of chronic (30 days) exposure to polystyrene microplastics (PS-MPs) of different sizes (50 nm and 2 µm) and at different concentrations (0.5 µg/L and 100 mg/L) to marine copepod Tigriopus japonicus. Polystyrene microplastics affected survival rates in size- and concentration-dependent manners. The LC50s values of 50 nm and 2 µm PS-MPs were 0.10 mg/L and 3.92 mg/L, respectively. The developmental time was delayed by 50 nm PS-MPs, and Usp expression was downregulated. Reproduction was negatively affected by 2 µm PS-MPs even at environmentally relevant concentrations; however, the expression of Vtg was not altered. The production rates of reactive oxygen species and nitric oxide also increased after exposure to PS-MPs; but this effect was independent of particle size. The expression levels of Cat and Tnf, genes related to oxidative stress and inflammation, respectively, were upregulated by exposure to PS-MPs, independently of particle size. Meanwhile, the level of oxidative stress in T. japonicus was not significantly affected by PS-MPs at environmentally relevant concentrations. This study suggests that nano-sized PS-MPs are not always more toxic than micro-sized PS-MPs, and that oxidative stress is a key factor in determining the toxic effect on T. japonicus at high concentrations.

Long-term exposure of the Mediterranean mussels, Mytilus galloprovincialis to polyethylene terephthalate microfibers: Implication for reproductive and neurotoxic effects.

As one of major types of microplastics (MPs), microfibers (MFs) are widely found in the marine ecosystem and can induce diverse impacts on various marine organisms. Sedentary species, such as mussels, can act as bioindicators for monitoring marine contamination. Hence, in this study, we used mussels (Mytilus galloprovincialis) to examine the toxicity of polyethylene terephthalate (PET) MFs of 100 µm size at concentrations of 0.0005, 0.1, 1, 10, and 100 mg/L for 32 days. PET MFs accumulated only in the stomachs and intestines of the mussels and caused digestive tubule atrophy. After exposure to PET MFs, no alteration in the mortality rate, shell height, length, and weight of the mussels was observed. However, the gonadal index decreased with increasing concentrations of PET MFs. This is because PET MFs decrease the sex hormones estradiol and testosterone in mussels, even at environmentally relevant concentrations. Furthermore, chronic exposure to PET MFs increased the activities of antioxidant-related (catalase and superoxide dismutase) and neurotoxicity-related (acetylcholine esterase) enzymes in the digestive gland and gill tissues of mussels. In addition, cellular immune parameters of apoptosis and DNA damage were observed in mussel hemocytes. Thus, this study demonstrates the risks of MPs in real marine environments by assessing how long-term exposure to low concentrations of PET MFs can cause potential sublethal impacts and reproductive failure in mussels.

Construction of full-length infectious cDNA clones of two Korean isolates of turnip mosaic virus breaking resistance in Brassica napus.

In this work, two new turnip mosaic virus (TuMV) strains (Canola-12 and Canola-14) overcoming resistance in canola (Brassica napus) were isolated from a B. napus sample that showed typical TuMV-like symptoms and was collected in the city of Gimcheon, South Korea, in 2020. The complete genome sequence was determined and an infectious clone was made for each isolate. Phylogenetic analysis indicated that the strains isolated from canola belonged to the World-B group. Both infectious clones, which used 35S and T7 promoters to drive expression, induced systemic symptoms in Nicotiana benthamiana and B. napus. To our knowledge, this is the first report of TuMV infecting B. napus in South Korea.

Reassortment of Infectious Clones of Radish Mosaic Virus Shows that Systemic Necrosis in Nicotiana benthamiana Is Determined by RNA1.

Three infectious clones of radish mosaic virus (RaMV) were generated from isolates collected in mainland Korea (RaMV-Gg) and Jeju Island (RaMV-Aa and RaMV-Bb). These isolates differed in sequences and pathogenicity. Examination of the wild-type isolates and reassortants between the genomic RNA1 and RNA2 of these three isolates revealed that severe symptoms were associated with RNA1 of isolates Aa or Gg causing systemic necrosis in Nicotiana benthamiana, or with RNA1 of isolate Bb for induction of veinal necrosis and severe mosaic symptoms in radish. Reverse transcription, followed by quantitative real-time PCR (Q-RT-PCR), results from infected N. benthamiana confirmed that viral RNA2 accumulation level was correlated to RaMV necrosis-inducing ability, and that the RNA2 accumulation level was mostly dependent on the origin of RNA1. However, in radish, Q-RT-PCR results showed more similar viral RNA2 accumulation levels regardless of the ability of the isolate to induce necrosis. Phylogenetic analysis of genomic RNAs sequence including previously characterized isolates from North America, Europe, and Asia suggest possible recombination within RNA1, while analysis of concatenated RNA1+RNA2 sequences indicates that reassortment of RNA1 and RNA2 has been more important in the evolution of RaMV isolates than recombination. Korean isolate Aa is a potential reassortant between isolates RaMV-J and RaMV-TW, while isolate Bb might have evolved from reassortment between isolates RaMV-CA and RaMV-J. The Korean isolates were shown to also be able to infect Chinese cabbage, raising concerns that RaMV may spread from radish fields to the Chinese cabbage crop in Korea, causing further economic losses.

Impact of polyethylene terephthalate microfiber length on cellular responses in the Mediterranean mussel Mytilus galloprovincialis.

Many studies have investigated the toxic effects of microplastics in marine organisms, but most studied nano-sized round microplastics at high concentrations and were not environmentally relevant. To understand the cellular toxicity of polyethylene terephthalate microfibers (PET-MFs) by length (50 and 100 µm), Mediterranean mussels (Mytilus galloprovincialis) were exposed to environmental (0.5 µg/L) and high (100 mg/L) MF concentrations for four days. Short PET-MFs accumulated in the lower intestinal organs of the mussels, but long PET-MFs were only observed in the upper intestinal organs. Both sized PET-MFs affected necrosis, DNA damage, reactive oxygen species, nitric oxide, and acetylcholinesterase (AChE) activity. Significant MF length-dependent effects occurred at environmentally relevant concentrations for DNA damage (100 µm MFs) and AChE activity (50 µm MFs). However, length effects disappeared at the higher exposure concentration. The current study provides potentially sensitive indicators to detect MFs exposure and the ecotoxicological implications of MFs in marine ecosystems.

Biomechanical properties of a new anatomical locking metal block plate for opening wedge high tibial osteotomy: uniplane osteotomy.

PURPOSE: The purpose of this study was to evaluate the biomechanical properties of a new anatomical locking metal block plate by comparing the initial biomechanical stability of three different fixation constructs for open wedge high tibial osteotomy (HTO). MATERIALS AND METHODS: Sawbones composite tibiae were used to make a 10-mm opening osteotomy model with uniplane technique. The osteotomy was secured with three different types of plates: Group I, new osteotomy plate without a metal block (n=5); Group II, new osteotomy plate with a 10-mm metal block (n=5); and Group III, two short metal block plates (n=5). Single load to failure test and staircase load-controlled cyclical failure test were performed. In the single load to failure test, the yield load, maximum failure load, and the displacement of the osteotomy gap were measured. In the staircase cyclical load to failure test, the total number of cycles to failure was recorded. Failure modes were observed during both single and cyclic load tests. RESULTS: Group II showed the highest yield and ultimate loads (1829±319 N, 3493±1250 N) compared to Group I (1512±157 N, 2422±769 N) and Group III (1369±378 N, 2157±210 N, p<0.05). The displacement of the opening gap in Group II (0.34±0.35 mm) was significantly lesser than the other groups (p<0.05). In the staircase cyclical load to failure test, the total number of cycles to failure was 12,860 at 950 N in Group III, 20,280 at 1,140 N in Group I, and 42,816 at 1,330 N in Group II (p<0.05). All the specimens showed complete fracture of the intact lateral sawbones area and slight displacement of the distal fragment of the specimens in the single load to test. None of the specimens showed deformed or broken screws and plates during the single load to test. During the fatigue test with staircase cyclic loading, no fracture of the lateral sawbones area was observed. CONCLUSIONS: This study demonstrated that the new anatomical locking metal block plate could provide sufficient primary stability for open wedge HTO. The addition of a metal block to this new plate can increase the stability of the osteotomy compared to the one without a metal block.