No abstract

Recent studies have reported that oral intake of gelatin hydrolysate has various beneficial effects, such as reduction of joint pain and lowering of blood sugar levels. In this study, we produced a novel gelatin hydrolysate using a cysteine-type ginger protease having unique substrate specificity with preferential peptide cleavage with Pro at the P2 position. Substantial amounts of X-hydroxyproline (Hyp)-Gly-type tripeptides were generated up to 2.5% (w/w) concomitantly with Gly-Pro-Y-type tripeptides (5%; w/w) using ginger powder. The in vivo absorption of the ginger-degraded gelatin hydrolysate was estimated using mice. The plasma levels of collagen-derived oligopeptides, especially X-Hyp-Gly, were significantly high (e.g., 2.3-fold for Glu-Hyp-Gly, p < 0.05) compared with those of the control gelatin hydrolysate, which was prepared using gastrointestinal proteases and did not contain detectable X-Hyp-Gly. This study demonstrated that orally administered X-Hyp-Gly was effectively absorbed into the blood, probably due to the high protease resistance of this type of tripeptide.

We assessed the requirement of the host cytoskeleton for the intracytosolic transport of incoming human cytomegalovirus (HCMV) capsids. Treatments with microtubule (MT)-depolymerizing drugs nocodazole and colchicine led to a drastic decrease in levels of IE1 antigen, whereas cytochalasin B had no effect on the level of IE1 as determined by Western blot analyses. Sequential treatment including nocodazole washout and removal of cell surface virion revealed that HCMV entry into the cells occurred normally in the absence of the MT network. This finding was also supported by data obtained by monitoring pUL83 signals with an immunofluorescent assay (IFA). Furthermore, we demonstrated a close association of incoming HCMV capsids with MTs by IFA and ultrastructural analyses. In the absence of the MT network, the capsids which had entered the cytoplasm did not move to close proximity of the nucleus. These data suggest that HCMV capsids associate with the MT network to facilitate their own movement to the nucleus before the onset of immediate-early (IE) gene expression and that this association is required to start efficient IE gene expression.Human cytomegalovirus (HCMV) is a prevalent pathogen responsible for significant morbidity and mortality in immunosuppressed individuals. It is a member of the betaherpesvirus family containing a double-stranded 230-kbp DNA genome, which is predicted to encode over 200 open reading frames (15). Like other herpesviruses, HCMV comprises three structural elements, an icosahedral capsid containing the DNA genome, a tegument, and an envelope. The dense tegument layer is distinguished from those of other herpesvirus families and is composed of a large number of proteins, but little is known about its structure or function (9). The infectious cycle of HCMV begins with multistep binding of virus to the cell surface, followed by penetration. Although release and dissociation of some tegument components occur upon entry (19), unlike those of alphaherpesviruses, the capsids are assumed to retain abundant structural tegument proteins and supposed to move towards the nuclear envelope (NE). Among the many unresolved processes, the mechanism of HCMV capsid transport in the cytoplasm remains unknown. Since movement of virus through the cytosol is not likely to occur by free diffusion but rather by a cellular transport system, it is conceivable that interactions of viral tegument proteins with the host machinery involved in cellular transport systems permits an active process (22). It has been reported that the efficient transport of herpes simplex virus type 1 (HSV-1) within cells in culture requires the microtubule (MT)-dependent motor proteins (8, 23), and interaction of tegument components with the motor proteins has been reported (7). MTs are organized in a polarized fashion with minus ends at the MT organization center (MTOC) and plus ends at the cell periphery; therefore, an interaction with MTs could facilitate proper movement of the cytosolic capsids to the NE, as has been shown for other v...