There are three classes of
There are three classes of receptors for herpes virus gD have been described [18,24]. Among those three, herpes virus entry mediator A (HveA) is also known as HVEM. This receptor is a member of the tumor necrosis factor receptor (TNFR) superfamily . The other class of receptors is HveC which is also known as nectin-1. It is related to immunoglobulin (Ig) superfamily members. It contains one V-like and two C-like Ig domains [12,26]. The third class of receptors is 3-O-sulfonated derivatives of heparan sulfate. This class of receptor originates by modification of heparan sulfate D-glu cosaminyl-3-O-sulfotransferase-3 . However, the biological consequences of this modification of receptors are being investigated.
There is an extended multi-domain architecture found in the structure of ectodomain fragment of glycoprotein gB in HSV1 . Moreover, there is striking structural similarity found between gB and the post fusion form of vesicular stomatitis virus glycoprotein G . These two glycoproteins are also related to a new family of fusion proteins, class III . Moreover, gB of HSV1 has a central, alpha-helical structure that is significant of the coiled coil domains of class I viral fusion proteins . The Ki8751 mg domain of the protein consists of elongated beta sheets which are interrupted by mutual hydrophobic regions. These regions may function as internal fusion loops . An ectodomain and a cytoplasmic tail syncytial mutation in gB are both needed for fusion-from-without (FFWO) . The ectodomain mutation maps to Domain III of the gB structure . Moreover, gB and gH/gL glycoproteins of HSV are involved in second step of nuclear egress, de-envelopment, fusion between the virion envelope and the outer nuclear membrane . The binding of gD protein to gD receptors such as nectin-1 and herpes virus entry modulator HVEM triggers gH/gL and gB, which mediate entry fusion .
Materials and methods
Results and discussion Glycoproteins B, C and D are very significant regarding attachment of herpes virus to host cells and infection. For example, gB contains multiple B-cell epitopes that are significant regarding antiviral drug design and vaccine development . Moreover, deletion of glycoprotein D may enable dendritic cells to activate the immune cells . While targeting gD may be an affective strategy to control viral infection . Hence, the enrich analysis of 3 glycoproteins (B, C and D) of eight different herpes viruses of different species may provide some very useful information regarding conserved sites and domains in these proteins. By applying different bioinformatics tools, including sequence alignment, phylogenetics analysis and structural bioinformatics analysis, the conserved sites in these glycoproteins which might be most significant regarding attachment and infection of the virus are highlighted.
Introduction Parascaris spp. is a cosmopolitan ascarid nematode that inhabits the small intestine of equids. These large nematodes reach up to 30 cm in length and are known to cause malnutrition and intestinal impaction when present in large numbers. Unfortunately, this parasite has developed resistance to macrocyclic lactone (ML) anthelmintics including ivermectin and moxidectin (Boersema et al., 2002). The first report of drug resistance in the United States was published in 2007 (Craig et al., 2007). Resistance is now considered to be relatively widespread in Europe and North America (Peregrine et al., 2014). Drug resistance has also been reported in Parascaris in South America (Molento et al., 2008), Oceania (Beasley et al., 2015; Bishop et al., 2014) and Asia (Shah et al., 2016). These findings have prompted the implementation of measures designed to delay the development of resistance in susceptible populations (Nielsen, 2016). The ML group of anthelmintics includes the avermectins and milbemycins. These agents selectively act on glutamate-gated chloride channels of invertebrates causing a slow and permanent state of hyperpolarization due to excessive chloride ion influx leading to paralysis (Wolstenholme, 2012). The effects are concentration-dependent, but species-specific differences in potency due to biochemical and pharmacological differences have been demonstrated (Geary and Moreno, 2012). Resistance to the ML anthelmintics has often been attributed to mutations and decreased expression of glutamate-gated chloride channels (Whittaker et al., 2017). However, an understanding of other mechanisms of resistance is beginning to emerge, and includes metabolism by cytochrome P450 (Riga et al., 2014), and efflux due to overexpression by ABCB1 transporter family (James and Davey, 2009; Xu et al., 1998).