The microsporidium Nosema ceranae is a high prevalent parasite of the European honey bee (Apis mellifera). This parasite is spreading across the world into its novel host. The developmental process and some mechanisms of N. ceranae infected honey bees has been studied thoroughly, however, few studies have been carried out in the mechanism of gene expression in N. ceranae during infection process. We therefore performed suppressive subtractive hybridization (SSH) approach to investigate the candidate genes of N. ceranae during its infection process. Each 96 clones of infected (forward) and non-infected (reverse) library were dipped onto the membrane for hybridization. A total of 118 differentially expressed sequence tags (ESTs) had been sequenced. For the host responses, 20% of ESTs (13 ESTs, 10 genes and 1 non-coding RNA) from forward library and 83% of ESTs (44 ESTs, 28 genes) from reverse library were identified as differentially expressed genes (DEGs) of the hosts. High percentage of DEGs involved in catalytic activity and metabolic processes, revealed the host gene expression change after N. ceranae infection might lead to the unbalance of physiological mechanism. Among the ESTs from forward library, 75.4% ESTs (49 ESTs belonged to 24 genes) were identified as N. ceranae genes. Of 24 N. ceranae genes, nine DEGs were subjected to real-time quantitative reverse transcription PCR (real-time qRT-PCR) for validation. The results indicated that these genes showed highly up-regulated during N. ceranae infection. Among nine N. ceranae genes, one N. ceranae gene (AAJ76_1600052943) showed the highest expression level after infection. These identified differentially expressed genes from this SSH could provide information about the pathological effects of N. ceranae. Validation of nine up-regulated N. ceranae genes revealed highly potential for the detection of early nosemosis in the field and provide insight for further applications.

The SARS (severe acute respiratory syndrome)-CoV (Coronavirus)-2 S(spike)-protein mRNA/cDNA currently being used as vaccines are antigenic but not antigens against SARS-CoV-2, that causes COVID (Coronavirus Disease) -19. Furthermore, the mRNA and cDNA antigenic vaccines also have potentials for homologous as well as heterologous recombination, primarily into the somatic cell DNA of the vaccine recipients. On the contrary, a SARS-CoV-2 RBD-protein antigen, a part of the S-protein, will directly stimulate antibody production against SARS-CoV-2. Hence, a vaccine composed of SARS-CoV-2 RBD-protein as a safer, fast acting, and effective vaccine against SARS-CoV-2 and thus against COVID-19. This is also useful for some immune compromised individuals.