Effectiveness of a broad-spectrum bivalent mRNA vaccine against SARS-CoV-2 variants in preclinical studies.

Vaccines utilizing modified messenger RNA (mRNA) technology have shown robust protective efficacy against SARS-CoV-2 in humans. As the virus continues to evolve in both human and non-human hosts, risk remains that the performance of the vaccines can be compromised by new variants with strong immune escape abilities. Here we present preclinical characterizations of a novel bivalent mRNA vaccine RQ3025 for its safety and effectiveness in animal models. The mRNA sequence of the vaccine is designed to incorporate common mutations on the SARS-CoV-2 spike protein that have been discovered along the evolutionary paths of different variants. Broad-spectrum, high-titer neutralizing antibodies against multiple variants were induced in mice (BALB/c and K18-hACE2), hamsters and rats upon injections of RQ3025, demonstrating advantages over the monovalent mRNA vaccines. Effectiveness in protection against several newly emerged variants is also evident in RQ3025-vaccinated rats. Analysis of splenocytes derived cytokines in BALB/c mice suggested that a Th1-biased cellular immune response was induced by RQ3025. Histological analysis of multiple organs in rats following injection of a high dose of RQ3025 showed no evidence of pathological changes. This study proves the safety and effectiveness of RQ3025 as a broad-spectrum vaccine against SARS-CoV-2 variants in animal models and lays the foundation for its potential clinical application in the future.

Preclinical evaluation of RQ3013, a broad-spectrum mRNA vaccine against SARS-CoV-2 variants.

The global emergence of SARS-CoV-2 variants has led to increasing breakthrough infections in vaccinated populations, calling for an urgent need to develop more effective and broad-spectrum vaccines to combat COVID-19. Here we report the preclinical development of RQ3013, an mRNA vaccine candidate intended to bring broad protection against SARS-CoV-2 variants of concern (VOCs). RQ3013, which contains pseudouridine-modified mRNAs formulated in lipid nanoparticles, encodes the spike (S) protein harboring a combination of mutations responsible for immune evasion of VOCs. Here we characterized the expressed S immunogen and evaluated the immunogenicity, efficacy, and safety of RQ3013 in various animal models. RQ3013 elicited robust immune responses in mice, hamsters, and nonhuman primates (NHP). It can induce high titers of antibodies with broad cross-neutralizing ability against the wild-type, B.1.1.7, B.1.351, B.1.617.2, and the newly emerging Omicron variants. In mice and NHP, two doses of RQ3013 protected the upper and lower respiratory tract against infection by SARS-CoV-2 and its variants. Furthermore, our safety assessment of RQ3013 in NHP showed no observable adverse effects. These results provide strong support for the evaluation of RQ3013 in clinical trials and suggest that it may be a promising candidate for broad protection against COVID-19 and its variants.

Gelation of cytoplasmic expanded CAG RNA repeats suppresses global protein synthesis.

RNA molecules with the expanded CAG repeat (eCAGr) may undergo sol-gel phase transitions, but the functional impact of RNA gelation is completely unknown. Here, we demonstrate that the eCAGr RNA may form cytoplasmic gel-like foci that are rapidly degraded by lysosomes. These RNA foci may significantly reduce the global protein synthesis rate, possibly by sequestering the translation elongation factor eEF2. Disrupting the eCAGr RNA gelation restored the global protein synthesis rate, whereas enhanced gelation exacerbated this phenotype. eEF2 puncta were significantly enhanced in brain slices from a knock-in mouse model and from patients with Huntington's disease, which is a CAG expansion disorder expressing eCAGr RNA. Finally, neuronal expression of the eCAGr RNA by adeno-associated virus injection caused significant behavioral deficits in mice. Our study demonstrates the existence of RNA gelation inside the cells and reveals its functional impact, providing insights into repeat expansion diseases and functional impacts of RNA phase transition.

Optimization of Strategy for Modified mRNA Inducing Cardiac-Specific Expression in Mice.

Lipid nanoparticle (LNP)-coated-modified RNA(modRNA) has been developed for enhancing the stability of modRNA, but it tends to accumulate in liver. The current study aimed to optimize strategy for increasing cardiac expression efficiency of modRNA. We synthesized Luciferase (Luc)-modRNA, and also developed 122Luc modRNA, a liver silencing Luc modRNA. Intramyocardial injection of naked Luc modRNA induced high bioluminescence signal in heart, but very low in other organs including liver. Luc modRNA-LNP injection showed the signal was increased by 5 folds in the heart and by 15,000 folds in the liver, compared to naked Luc modRNA group. In comparison with Luc modRNA-LNP group, the liver signal was decreased to 0.17%, while cardiac signal showed a slight drop by intramyocardial injection of 122Luc-modRNA-LNP. Our data revealed that intramyocardial injection of naked modRNA could effectively induced cardiac-specific expression. For cardiac delivery of Luc modRNA-LNP, 122modRNA-LNP enhances specificity of cardiac expression by abolishing liver signal.

Visual Detection of Water Content Range of Seabuckthorn Fruit Based on Transfer Deep Learning.

To realize the classification of sea buckthorn fruits with different water content ranges, a convolution neural network (CNN) detection model of sea buckthorn fruit water content ranges was constructed. In total, 900 images of seabuckthorn fruits with different water contents were collected from 720 seabuckthorn fruits. Eight classic network models based on deep learning were used as feature extraction for transfer learning. A total of 180 images were randomly selected from the images of various water content ranges for testing. Finally, the identification accuracy of the network model for the water content range of seabuckthorn fruit was 98.69%, and the accuracy on the test set was 99.4%. The program in this study can quickly identify the moisture content range of seabuckthorn fruit by collecting images of the appearance and morphology changes during the drying process of seabuckthorn fruit. The model has a good detection effect for seabuckthorn fruits with different moisture content ranges with slight changes in characteristics. The migration deep learning can also be used to detect the moisture content range of other agricultural products, providing technical support for the rapid nondestructive testing of moisture contents of agricultural products.

Hot Air Drying of Seabuckthorn (Hippophae rhamnoides L.) Berries: Effects of Different Pretreatment Methods on Drying Characteristics and Quality Attributes.

Seabuckthorn berries are difficult to dry because the outermost surface is covered with a dense wax layer, which prevents moisture transfer during the drying process. In this study, uses of ultrasonic-assisted alkali (UA), pricking holes in the skin (PH) and their combination (UA + PH) as pretreatment methods prior to hot air drying and their effects on drying characteristics and quality attributes of seabuckthorn berries were investigated. Selected properties include color, microstructure, rehydration capacity, as well as total flavonoids, phenolics and ascorbic acid contents. Finally, the coefficient of variation method was used for comprehensive evaluation. The results showed that all pretreatment methods increased the drying rate; the combination of ultrasonic-assisted alkali (time, 15 min) and pricking holes (number, 6) (UA15 + PH6) had the highest drying rate that compared with the control group, the drying time was shortened by 33.05%; scanning electron microscopy images revealed that the pretreatment of UA could dissolve the wax layer of seabuckthorn berries, helped to form micropores, which promoted the process of water migration. All the pretreatments reduced the color difference and increased the lightness. The PH3 samples had the highest value of vitamin C content (54.71 mg/100 g), the UA5 and PH1 samples had the highest value of total flavonoid content (11.41 mg/g) and total phenolic content (14.20 mg/g), respectively. Compared to other pretreatment groups, UA15 + PH6 achieved the highest quality comprehensive score (1.013). Results indicate that UA15 + PH6 treatment is the most appropriate pretreatment method for improving the drying characteristics and quality attributes of seabuckthorn berries.

Impact of spectral filtering on pulse breaking-up and noise-like pulse generation in all-normal dispersion fiber lasers.

Based on mathematic simulations, the impact of spectral filtering on pulse breaking up and noise-like pulse generation in all-normal-dispersion fiber lasers are investigated. Three types of spectrum filters are employed in the simulations, which have a Gaussian-shaped profile, super-Gaussian-shaped profile, and sinusoidal-shaped profile, respectively. With the Gaussian-shaped filter, the pulse breaking-up process is discussed. The super-Gaussian-shaped filter and the sinusoidal-shaped filter have two different formation mechanisms for noise-like pulses and are revealed. In addition, with the sinusoidal-shaped filter, dissipative solitons of different central wavelengths are achieved.

Cetaceans and microplastics: First report of microplastic ingestion by a coastal delphinid, Sousa chinensis.

In the Anthropocene, marine microplastic debris has been rapidly increasing and interacting with wildlife. As apex predators, cetaceans have been proven to be ideal sentinel species to indicate ecosystem changes and umbrella and flagship species to help develop environmental management strategies. Here, we report the presence of microplastics in the intestines of Sousa chinensis for the first time, which highlights the potential impacts of microplastic pollution in coastal environments. Microplastics were detected in the intestinal contents of both adult and calf individuals, indicating that consumption of prey and unintentional ingestion are the potential pathways for microplastic accumulation in Sousa chinensis. The properties of the microplastics indicated that fibers, white and blue items, 1-5 mm items, and polyester were the predominant shapes, colors, sizes and plastic materials, respectively. More microplastics were detected in the foreguts and midguts than in the hindguts, which may be correlated with the specific intestinal structure of Sousa. This study indicates that coastal delphinids might suffer from microplastic pollution, even young calves. The sample size in this study is limited, whereas it's a starting point for assessing microplastics in the endangered coastal delphinid, Sousa. We suggest that assessments of the risks of microplastic consumption by cetaceans and the presence of microplastics in their habitats should be conducted at a global scale. Moreover, further works should be done to look for evidence of adverse effects of microplastics pollution on cetaceans.

Microplastic pollution in the Maowei Sea, a typical mariculture bay of China.

The ingestion of microplastics by organisms presents a potential exposure route for humans via seafood consumption. Although mariculture has become an essential source of seafood worldwide, the content of microplastics in the mariculture zone has received less scrutiny than in the wild environment. The Maowei Sea is a semi-closed bay that is rich in fishery resources. The specific levels of microplastics in the Maowei Sea and its fishery products remain undetermined. In this paper, we detail the distributions and characteristics of microplastics in the aquaculture water and biota of the Maowei Sea. Microplastics were detected in the range of 1.2-10.1 particles/L in Maowei Sea surface water, with high microplastic content in estuarine oyster nursery (10.1 particles/L) and Qinzhou harbor (8.8-9.5 particles/L) sites. In water samples from the three inflowing rivers, the abundances ranged from 2.9 to 4.5 particles/L, which is comparable to that in Maowei Sea surface water. Of 66 collected fish belonging to 12 species, microplastics were observed in all of the gastrointestinal tracts (GITs) and in the gills of 40 individuals. In the GIT and gill tests, the abundances of microplastics ranged from 2.0 to 14.0 and from 0.0 to 8.5 particles/individual, respectively. The enhanced particles/individual figures in the GIT relative to the gill are particularly noteworthy. Demersal species showed significantly higher abundances of microplastics than pelagic species (p < 0.05). Microplastics were also detected in the soft tissues of all oyster samples, with abundances ranging from 3.2 to 8.6 particles/individual. The microplastic composition was dominated by rayon and polyester and tended to be white in color and fibrous in shape. Altogether, these results correspond to high levels of microplastics in the Maowei Sea. As the study region is a mariculture bay, the observed microplastics contamination in its fishery products presents a route for human exposure. CAPSULE ABSTRACT: Microplastics are widespread in the aquaculture water and biota in the Maowei Sea, a mariculture bay.