The nucleocapsid (N) protein of a coronavirus plays a crucial role in virus assembly and in its RNA transcription. It is important to characterize a virus at the nucleotide level to discover the virus's genomic sequence variations and similarities relative to other viruses that could have an impact on the functions of its genes and proteins. This entails a comprehensive and comparative analysis of the viral genomes of interest for preferred nucleotides, codon bias, nucleotide changes at the 3 rd position (NT3s), synonymous codon usage and relative synonymous codon usage. In this study, the variations in the N proteins among 13 different coronaviruses (CoVs) were analysed at the nucleotide and amino acid levels in an attempt to reveal how these viruses adapt to their hosts relative to their preferred codon usage in the N genes. The results revealed that, overall, eighteen amino acids had different preferred codons and eight of these were over-biased. The N genes had a higher AT% over GC% and the values of their effective number of codons ranged from 40.43 to 53.85, indicating a slight codon bias. Neutrality plots and correlation analyses showed a very high level of GC3s/GC correlation in porcine epidemic diarrhea CoV (pedCoV), followed by Middle East respiratory syndrome-CoV (MERS CoV), porcine delta CoV (dCoV), bat CoV (bCoV) and feline CoV (fCoV) with r values 0.81, 0.68, -0.47, 0.98 and 0.58, respectively. These data implied a high rate of evolution of the CoV genomes and a strong influence of mutation on evolutionary selection in the CoV N genes. This type of genetic analysis would be useful for evaluating a virus's host adaptation, evolution and is thus of value to vaccine design strategies.

Methotrexate (MTX) is a commonly used chemotherapeutic agent. Oxidative stress and inflammation have been proved in the development of MTX toxicity. Paeonol is a natural phenolic compound with various pharmacological activities including antioxidant and anti-inflammatory properties. The aim of the present study was to evaluate the protective effect of paeonol against MTX-induced cardiac toxicity in rats and to evaluate the various mechanisms that underlie this effect. Paeonol (100 mg/kg) was administered orally for 10 days. MTX cardiac toxicity was induced at the end of the fifth day of the experiment, with or without paeonol pretreatment. MTX-induced cardiac damage is evidenced by a distortion in the normal cardiac histological structure, with significant oxidative and nitrosative stress shown as a significant increase in NADPH oxidase-2, malondialdehyde, and nitric oxide levels along with a decrease in reduced glutathione concentration and superoxide dismutase activity compared to the control group. MTX-induced inflammatory effects are evidenced by the increased cardiac toll-like receptor 4 (TLR4) mRNA expression and protein level as well as increased cardiac tumor necrosis factor- (TNF-) α and interleukin- (IL-) 6 levels along with increased nuclear factor- (NF-) κB/p65 immunostaining. MTX increased apoptosis as shown by the upregulation of cardiac caspase 3 immunostaining. Paeonol was able to correct the oxidative and nitrosative stress as well as the inflammatory and apoptotic parameters and restore the normal histological structure compared to MTX alone. In conclusion, paeonol has a protective effect against MTX-induced cardiac toxicity through inhibiting oxidative and nitrosative stress and suppressing the TLR4/NF-κB/TNF-α/IL-6 inflammatory pathway, as well as causing an associated reduction in the proapoptotic marker, caspase 3.

Carbapenem-resistant Acinetobacter baumannii is becoming increasingly prevalent in patients with diabetes mellitus in the Middle East. We examined the relationship of these bacteria and their resistance mechanisms to the diabetic disease status of patients in Saudi Arabia. Susceptibilities of 271 isolates to carbapenems, tigecycline and colistin were determined, followed by detection of carbapenemase genes. A bla VIM gene was detected in~95 % of isolates; bla OXA-23 and bla OXA-40 genes were also prevalent. Diabetic patients were significantly more likely to carry carbapenem-resistant isolates. Carbapenem-resistant A. baumannii is a serious problem in diabetic patients, and molecular detection of resistance mechanisms in these isolates is required.

The Middle East respiratory syndrome coronavirus (MERS-CoV) is an emerging virus that causes infection with a potentially fatal outcome. Dendrimers are highly branched molecules that can be added to antiviral preparations to improve their delivery, as well as their intrinsic antiviral activity. Studies on identifying anti-MERS-CoV agents are few. Three types of polyanionic dendrimers comprising the terminal groups sodium carboxylate (generations 1.5, 2.5, 3.5, and 4.5), hydroxyl (generations 2, 3, 4, and 5), and succinamic acid (generations 2, 3, 4, and 5) and polycationic dendrimers containing primary amine (generations 2, 3, 4, and 5) were used to assess their antiviral activity with the MERS-CoV plaque inhibition assay. The hydroxyl polyanionic set showed a 17.36% to 29.75% decrease in MERS-CoV plaque formation. The most potent inhibition of MERS-CoV plaque formation was seen by G (1.5)-16COONa (40.5% inhibition), followed by G(5)-128SA (39.77% inhibition). In contrast, the cationic dendrimers were cytotoxic to Vero cells. Polyanionic dendrimers can be added to antiviral preparations to improve the delivery of antivirals, as well as the intrinsic antiviral activity. K E Y W O R D S antiviral agents, cell cultures, coronavirus, research and analysis methods, virus classification

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