Avian coronavirus Spike Glycoprotein Ectodomain Shows a Low Codon Adaptation to Gallus gallus with Virus-Exclusive Codons in Strategic Amino Acids Positions

This is a study on the Avian coronavirus IBV and chicken host-relationship from the codon usage point of view based on fifty-nine non-redundant IBV S1 sequences (nt 1-507) from strains detected worldwide and chicken tissue-specific protein genes sequences from IBV-replicating sites. The effective number of codons (ENC) values ranged from 36 to 47.8, indicating a high-to-moderate codon usage bias. The highest IBV codon adaptation index (CAI) value was 0.7, indicating a distant virus versus host synonymous codons usage. The ENC x GC3 % curve indicates that both mutational pressure and natural selection are the driving forces on codon usage pattern in S1. The low CAI values agree with a low S protein expression and considering that S protein is a determinant for attachment and neutralization, this could be a further mechanism besides mRNA transcription attenuation for a low expression of this protein leading to an immune camouflage.

Analysis of expressed sequence tags from the agarophyte Gracilaria tenuistipitata (Rhodophyta)

A total of 3,631 expressed sequence tags (ESTs) were established from two size-selected cDNA libraries made from the tetrasporophytic phase of the agarophytic red alga Gracilaria tenuistipitata. The average sizes of the inserts in the two libraries were 1,600 bp and 600 bp, with an average length of the edited sequences of 850 bp. Clustering gave 2,387 assembled sequences with a redundancy of 53%. Of the ESTs, 65% had significant matches to sequences deposited in public databases, 11% to proteins without known function, and 35% were novel. The most represented ESTs were a Na/K-transporting ATPase, a hedgehog-like protein, a glycine dehydrogenase and an actin. Most of the identified genes were involved in primary metabolism and housekeeping. The largest functional group was thus genes involved in metabolism with 14% of the ESTs; other large functional categories included energy, transcription, and protein synthesis and destination. The codon usage was examined using a subset of the data, and the codon bias was found to be limited with all codon combinations used.

Human respiratory syncytial virus N, P and M protein interactions in HEK-293T cells

Characterization of Human Respiratory Syncytial Virus (HRSV) protein interactions with host cell components is crucial to devise antiviral strategies. Viral nucleoprotein, phosphoprotein and matrix protein genes were optimized for human codon usage and cloned into expression vectors. HEK-293T cells were transfected with these vectors, viral proteins were immunoprecipitated, and co-immunoprecipitated cellular proteins were identified through mass spectrometry. Cell proteins identified with higher confidence scores were probed in the immunoprecipitation using specific antibodies. The results indicate that nucleoprotein interacts with arginine methyl-transferase, methylosome protein and Hsp70. Phosphoprotein interacts with Hsp70 and tropomysin, and matrix with tropomysin and nucleophosmin. Additionally, we performed immunoprecipitation of these cellular proteins in cells infected with HRSV, followed by detection of co-immunoprecipitated viral proteins. The results indicate that these interactions also occur in the context of viral infection, and their potential contribution for a HRSV replication model is discussed.

First observation of alternative food usage (extrafloral nectar) by the assassin bug Atopozelus opsimus (Hemiptera, Reduviidae)

First observation of alternative food usage (extrafloral nectar) by the assassin bug Atopozelus opsimus (Hemiptera, Reduviidae). Assassin bugs (Reduviidae) are voracious insects that prey on other arthropods. Recent evidences have pointed out that these predators also feed on plant derived substances in rare opportunities. The present study describes the feeding behavior of the reduviid Atopozelus opsimus on extrafloral nectaries of Inga vera (Fabaceae) in a Neotropical savanna area. It was investigated if the insects feed more frequently of extrafloral nectar or prey, and if individuals of different stages of development vary according to feeding behavior. Notably, the results suggest that the diet of all instars and adults consist mainly of extrafloral nectar (N = 1013), in detriment of captured prey ingestion (N = 18). Also, there was no variation on feeding behavior and life stage.