Ironment and contact with host interface. Of the 184 expressed collagen genes in O. dentatum, 58% were highly transcribed in individual stages, indicating that collagens are expressed in waves coinciding with the four molts. This dynamic, development-related transcriptional profile for this relatively large complement of genes is consistent with previous studies in which numerous collagen genes were transcribed in molting worms under nutrient-rich conditions, but no such genes were transcribed in developmentally arrested larvae. In the L4 and/or adult stages of O. dentatum, there was an abundance of peptidase genes with 181223-80-3 web enriched transcription. Conspicuous were those Piclidenoson site encoding excretory/ secretory peptidases of various clans, including cysteine peptidases and metallopeptidases, which are likely involved in the degradation of cells and digestion of proteins following establishment in the gut, and which may be critical for growth, development and survival of O. dentatum in the porcine host and might represent potential drug targets. Subsequently, the functions of genes with enriched transcription in parasitic stages but not free-living stages of O. dentatum and without orthologs in C. elegans were studied. Such genes were linked to the cellular components such as “extracellular space” and “lysosome” as well as biological processes including “proteolysis”. Specifically, the genes related to these enrichment terms encoded C13, cathepsin B, papain family and pepsin A family type peptidase activities, all of which are recognized to be lysosome components and/or involved in digesting tissues or extracellular matrices, which are all functions that are critical to the feeding and survival of the parasite inside the host animal. For example, 63 of all 87 cathepsin B genes were transcribed exclusively in the parasitic stages, consistent with evidence that these genes are up-regulated in parasitic nematodes. In addition, 16 of 21 genes encoding nematode fatty acid retinoid binding proteins were transcribed exclusively in parasitic stages. FAR proteins do not have homologs in mammals and are likely localized to the surface of parasites, placing them in a prime position for interactions with the host animal. As 84 of the 179 genes enriched in parasitic stages could not be functionally annotated, they may relate to critical processes linked to parasitism. Author Manuscript Author Manuscript Author Manuscript Author Manuscript Biotechnol Adv. Author manuscript; available in PMC 2016 November 01. Tyagi et al. Page 7 5. Gender-enriched transcription Groups of genes were studied that are differentially transcribed between female and male adults of O. dentatum. The transcription of 2,682 and 1,519 genes was enriched in females and males, respectively. A large number of these genes had orthologs in C. elegans, with 80% of the female-specific and 61% of male-specific transcripts with significant sequence identity to genes of C. elegans. Both the female and male gene sets were enriched for molecules linked predominantly to growth and reproduction, and germline, embryonic and genital development. The female-enriched set had orthologs associated with the germline, oogenesis or egg laying, embryogenesis, 
vulva development and/or other reproductive PubMed ID:http://www.ncbi.nlm.nih.gov/pubmed/1985460 and biological processes in C. elegans. In addition, vitellogenin genes were transcribed exclusively in females. Vitellogenins are egg-yolk precursor proteins expressed in almost all oviparous animals; these proteins are.Ironment and contact with host interface. Of the 184 expressed collagen genes in O. dentatum, 58% were highly transcribed in individual stages, indicating that collagens are expressed in waves coinciding with the four molts. This dynamic, development-related transcriptional profile for this relatively large complement of genes is consistent with previous studies in which numerous collagen genes were transcribed 
in molting worms under nutrient-rich conditions, but no such genes were transcribed in developmentally arrested larvae. In the L4 and/or adult stages of O. dentatum, there was an abundance of peptidase genes with enriched transcription. Conspicuous were those encoding excretory/ secretory peptidases of various clans, including cysteine peptidases and metallopeptidases, which are likely involved in the degradation of cells and digestion of proteins following establishment in the gut, and which may be critical for growth, development and survival of O. dentatum in the porcine host and might represent potential drug targets. Subsequently, the functions of genes with enriched transcription in parasitic stages but not free-living stages of O. dentatum and without orthologs in C. elegans were studied. Such genes were linked to the cellular components such as “extracellular space” and “lysosome” as well as biological processes including “proteolysis”. Specifically, the genes related to these enrichment terms encoded C13, cathepsin B, papain family and pepsin A family type peptidase activities, all of which are recognized to be lysosome components and/or involved in digesting tissues or extracellular matrices, which are all functions that are critical to the feeding and survival of the parasite inside the host animal. For example, 63 of all 87 cathepsin B genes were transcribed exclusively in the parasitic stages, consistent with evidence that these genes are up-regulated in parasitic nematodes. In addition, 16 of 21 genes encoding nematode fatty acid retinoid binding proteins were transcribed exclusively in parasitic stages. FAR proteins do not have homologs in mammals and are likely localized to the surface of parasites, placing them in a prime position for interactions with the host animal. As 84 of the 179 genes enriched in parasitic stages could not be functionally annotated, they may relate to critical processes linked to parasitism. Author Manuscript Author Manuscript Author Manuscript Author Manuscript Biotechnol Adv. Author manuscript; available in PMC 2016 November 01. Tyagi et al. Page 7 5. Gender-enriched transcription Groups of genes were studied that are differentially transcribed between female and male adults of O. dentatum. The transcription of 2,682 and 1,519 genes was enriched in females and males, respectively. A large number of these genes had orthologs in C. elegans, with 80% of the female-specific and 61% of male-specific transcripts with significant sequence identity to genes of C. elegans. Both the female and male gene sets were enriched for molecules linked predominantly to growth and reproduction, and germline, embryonic and genital development. The female-enriched set had orthologs associated with the germline, oogenesis or egg laying, embryogenesis, vulva development and/or other reproductive PubMed ID:http://www.ncbi.nlm.nih.gov/pubmed/1985460 and biological processes in C. elegans. In addition, vitellogenin genes were transcribed exclusively in females. Vitellogenins are egg-yolk precursor proteins expressed in almost all oviparous animals; these proteins are.