New porcine rotavirus serotype antigenically related to human rotavirus serotype 3.

Serotyping of porcine rotaviruses isolated in MA104 cells from Australian piglets with diarrhea showed that two strains belonged to serotype 3 and one strain was antigenically similar to the OSU strain of porcine rotavirus (serotype 5). In addition, neutralizing antibodies to human rotavirus serotype 4 (ST-3 strain) were detected in serum samples from sows in one area, and so it seems probable that porcine rotaviruses of at least three serotypes occur in Australia.     

Bacterial expression of the major antigenic regions of porcine rotavirus VP7 induces a neutralizing immune response in mice.

The outer capsid protein of rotavirus, VP7, is a major neutralization antigen. A chimeric protein comprising Escherichia coli (E. coli) outer membrane protein A (OmpA) and part of porcine rotavirus VP7 containing all three antigenic regions (217 amino acids) was expressed in Salmonella and E. coli as an outer-membrane associated protein. Mice immunized intraperitoneally or orally, respectively, with live E. coli or Salmonella cells expressing this chimeric protein produced antibodies against native VP7 as determined by enzyme-linked immunosorbent assays and neutralization tests. This indicates that the VP7 fragment from a porcine rotavirus which is antigenically similar to human rotavirus serotype 3, when expressed in bacteria as a chimeric protein, can form a structure resembling its native form at least in some of the major neutralization domains. These results indicate that the use of a live bacterial vector expressing rotavirus VP7 may represent a strategy for the development of vaccines against rotavirus-induced diarrhoea in infants.     

Molecular epidemiology of Plasmodium falciparum resistance to antimalarial drugs in Indonesia

The extent of gene polymorphisms associated with resistance to chloroquine and sulfadoxine-pyrimethamine was examined in field isolates of Plasmodium falciparum from Indonesia. Eight malaria-endemic areas, representing a broad region of the western and eastern Indonesian Archipelago were surveyed. Blood from 20-50 patients was collected at each site, DNA was isolated, and the sequences of four different genes (dihydrofolate reductase [dhfr], dihydropteroate synthase [dhps], P. falciparum multidrug resistance 1 [pfmdr1], and P. falciparum chloroquine resistance transporter [pfcrt]) were analyzed using polymerase chain reaction and restriction fragment length polymorphisms to detect polymorphisms previously shown to be associated with resistance. This analysis identified polymorphisms in dhfr at 108-Asn/Thr, 16-Val, and 59-Arg. Polymorphisms in dhps were found less frequently, either 437-Gly alone or paired with 540-Glu. The pfcrt 76-Thr polymorphism was fixed in all parasite populations and pfmdr1 86-Tyr polymorphisms in all populations except in the most eastern regions. The pfmdr1 1042-Asp polymorphism occurred less frequently. These findings indicate that polymorphisms in genes associated with drug resistance in P. falciparum are found across a broad region of Indonesia.     

The Role of PTHrP in Pancreatic Beta-Cells and Implications for Diabetes Pathophysiology and Treatment

Diabetes is one of the fastest growing diseases worldwide, with an immense economic and health burden attached. It is now well accepted that a deficiency of functional insulin-producing pancreatic beta-cells is the main cause for all forms of diabetes. Several approaches are being taken to increase functional beta-cell mass. These include differentiation of new beta-cells from stem cells or progenitor cells, transdifferentiation of beta-cells from other mature cell types, as well as finding ways to enhance the function, proliferation, survival, and regeneration of preexisting beta-cells. This article enumerates on the role of parathyroid hormone-related protein (PTHrP) and its mode of action on pancreatic beta-cell function, proliferation, and survival in rodents as well as in human beta-cells. A further understanding of the mechanism of action of PTHrP and its role in the normal physiology and pathophysiology of the beta-cell will be important for its potential use in future as a therapeutic treatment for diabetes.     

Effects of non-digestible carbohydrates on the growth of estrogen-dependent human breast cancer (MCF-7) tumors implanted in ovariectomized athymic mice

Non-digestible carbohydrates (NDC(4)) have been used as a low-calorie sweetener and prebiotics that stimulate the growth of certain intestinal bacteria that support healthy colon conditions. In this study, we examined the dietary effect of commercially available NDCs on estrogen receptor positive (ER+) human breast cancer. We conducted a feeding study of fructooligosaccharides (FOSs), Fibersol 2 (F2; digestion resistant maltodextrin), Hi-Maize (HM; high amylose cornstarch), and Frutafit (FF; a range of powdered inulins) (5% in diet, w/w) to evaluate their effects on the growth of ER(+) human breast cancer (MCF-7) tumors in the presence of 17β-estradiol (E(2)) using an athymic xenograft model. F2, HM, and FOSs supplementation significantly reduced E(2)-stimulated MCF-7 tumor growth by inhibiting cellular proliferation (Ki-67) and increasing apoptosis (M30) in tumors. F2, HM, and FOSs treatments also lowered serum E(2) level and reduced uterine weight compared to the control diet. NDCs treatments downregulated relative mRNA expression of the E(2)-responsive gene markers pS2, bcl2, bcl-xL, and cyclin D1 in MCF-7 tumors. In conclusion, the NDC intake may have a protective effect against ER(+) tumors by inhibiting cellular proliferation and increasing apoptosis.     

Identification of equine herpesvirus 4 glycoprotein G: a type-specific, secreted glycoprotein.

Equine herpesvirus 4 (EHV4) glycoproteins of M(r) 63K and 250K were identified in the supernatant of infected cell cultures. The 63K glycoprotein was type-specific; that is, it reacted with monospecific sera from horses that had been immunized or infected with EHV4, but not with monospecific sera from horses immunized or infected with EHV1, a closely related alphaherpesvirus. It was postulated that the secreted protein may be the homologue of similarly secreted glycoproteins of herpes simplex virus 2 glycoprotein G (HSV2 gG) and pseudorabies virus (PRV) gX, which is the homologue of HSV2 gG. The US region of the EHV4 genome, toward the internal repeat structure, was sequenced. Four open reading frames (ORFs) were identified of which ORF4 showed 52% similarity to the gene-encoding PRV gX in a 650-nucleotide region. ORF4 coded for a primary translational product of 405 amino acids which has a predicted size of 44K. The amino acid sequence of ORF4 showed 28% identity with PRV gX and 16% identity with HSV2 gG, although significantly greater identity was observed in the N-terminal region including the conservation of 4 cysteine residues. Accordingly, we designate ORF4 as EHV4 gG. The predicted amino acid sequence of the EHV4 gG showed characteristics of an envelope glycoprotein. Expression of the entire EHV4 gG gene in the bacterial expression vector pGEX-3X produced a type-specific fusion protein of M(r) 70K of which the gG portion composes 43K. Antibody that was affinity purified from selected portions of Western blots containing the 70K gG fusion protein reacted with the 63K secreted glycoprotein. Conversely, antibody affinity purified to the 63K secreted product reacted with the 70K gG fusion protein. These results showed that the EHV4 63K secreted glycoprotein was EHV4 gG, the third alphaherpesvirus gG homologue known to be, at least in part, secreted. The type-specificity of this glycoprotein provides, for the first time, the opportunity to differentiate between antibodies present in polyclonal sera from EHV4, EHV1, and dual-infected horses and this has important implications for understanding the epidemiology of these viruses.