Chemical and heating treatments of ionic monolayer-protected clusters (IMPCs) with different surface counter anions.

This paper shows an in-depth study on the chemical and thermal responses of two ionic monolayer-protected gold clusters (Oct(4)N(+-)Br- and Oct(4)N(+-)O(3)SS-IMPCs). Two IMPCs displayed completely different phase-transfer behaviors when the solutions were in contact with the aqueous solution containing N-(2-mercaptopropionyl)glycine (tiopronin). Not Oct(4)N(+-)O(3)SS-IMPCs but Oct(4)N(+-)Br-IMPCs experienced a facile phase transfer from the organic layer to the aqueous layer, which was resulted from the displacement of ionic ligands by tiopronin monolayers on the gold nanoparticle surface.

Nitrated indenoisoquinolines as topoisomerase I inhibitors: a systematic study and optimization.

The biological activity of indenoisoquinoline topoisomerase I (Top1) inhibitors can be greatly enhanced depending on the choice of substituents on the aromatic rings and lactam side chain. Previously, it was discovered that a 3-nitro group and a 9-methoxy group afforded enhanced biological activity. In the present investigation, indenoisoquinoline analogues were systematically prepared using combinations of nitro groups, methoxy groups, and hydrogen atoms in an effort to understand the contribution of each group toward cytotoxicity and Top1 inhibition.

Optimization of the indenone ring of indenoisoquinoline topoisomerase I inhibitors.

Two series of indenoisoquinoline topoisomerase I inhibitors have been prepared to investigate optimal substituents on the indenone ring at the 9-position. The more exhaustive series was prepared using a nitrated isoquinoline ring that has been previously demonstrated to enhance biological activity. After preliminary biological evaluation, a more focused series of inhibitors was prepared utilizing a 2,3-dimethoxy-substituted isoquinoline ring.

Hypoallergens for allergen-specific immunotherapy by directed molecular evolution of mite group 2 allergens.

Allergen-specific immunotherapy is the only treatment that provides long lasting relief of allergic symptoms. Currently, it is based on repeated administration of allergen extracts. To improve the safety and efficacy of allergen extract-based immunotherapy, application of hypoallergens, i.

The expression of lactate dehydrogenase is important for the cell cycle of Toxoplasma gondii.

In Toxoplasma gondii, lactate dehydrogenase is encoded by two independent and developmentally regulated genes LDH1 and LDH2. These genes and their products have been implicated in the control of a metabolic flux during parasite differentiation. To investigate the significance of LDH1 and LDH2 in this process, we generated stable transgenic parasite lines in which the expression of these two expressed isoforms of lactate dehydrogenase was knocked down in a stage-specific manner.

Serotyping of Toxoplasma gondii infections in humans using synthetic peptides.

To determine whether the characteristics of disease due to Toxoplasma gondii (toxoplasmosis) are dependent on the infecting strain, we have developed an enzyme-linked immunosorbent assay for typing strains that uses infection serum reacted against polymorphic peptides derived from Toxoplasma antigens SAG2A, GRA3, GRA6, and GRA7. Pilot studies with infected mice established the validity of the approach, which was then tested with human serum. In 8 patients who had Sabin-Feldman dye test titers >64 and for whom the infecting strain type was known, the peptides correctly distinguished type II from non-type II infections.

Evidence for nuclear localisation of two stage-specific isoenzymes of enolase in Toxoplasma gondii correlates with active parasite replication.

The protozoan parasite Toxoplasma gondii has a complex life cycle involving the developmental transition between the asexual exo-enteric stages (tachyzoites and bradyzoites) and the coccidian (sexual and asexual) forms (schizonts, macrogametes and microgametes). Previous work has established the stage-specific expression of certain proteins including two glycolytic isoenzymes of enolase and lactate dehydrogenase in T. gondii.

Protective effects of immunization with a recombinant cyst antigen in mouse models of infection with Toxoplasma gondii tissue cysts.

A portion of the major Toxoplasma gondii tissue cyst antigen (MAG1) was expressed in bacteria as a fusion to glutathione S-transferase (GST) and the purified fusion protein (rMAG1) was used to immunize mice in an attempt to induce protective immunity against challenge with live cysts from the T. gondii ME49 strain. Sixty percent of mice immunized with rMAG1 and challenged with 500 cysts of the T.

The kinetic properties and sensitivities to inhibitors of lactate dehydrogenases (LDH1 and LDH2) from Toxoplasma gondii: comparisons with pLDH from Plasmodium falciparum.

Toxoplasma gondii differentially expresses two forms of lactate dehydrogenase in tachyzoites and bradyzoites, respectively, designated LDH1 and LDH2. Previously it was demonstrated that LDH1 and LDH2 share a unique structural feature with LDH from the malarial parasite Plasmodium falciparum (pLDH), namely, the addition of a five-amino acid insert into the substrate specificity loops. pLDH exhibits a number of kinetic properties that previously were thought to be unique to pLDH.

Simple and efficient method for measuring anti-toxoplasma immunoglobulin antibodies in human sera using complement-mediated lysis of transgenic tachyzoites expressing beta-galactosidase.

A simple and efficient method using transgenic Toxoplasma gondii tachyzoites expressing beta-galactosidase was developed for detection of specific antibodies against the parasite in sera of patients. The titers obtained with the new test were similar to those obtained with the Sabin-Feldman dye test run in parallel. Although significant changes in endpoint titers were not observed when sera drawn sequentially at 2- to 3-week intervals were tested with both procedures, apparent differences in antibody affinity were observed with the new test which were not perceptible with the Sabin-Feldman dye test.

Strain typing of Toxoplasma gondii: comparison of antigen-coding and housekeeping genes.

Molecular characterization of Toxoplasma gondii isolates is central for understanding differences in disease transmission and manifestations. Only 3 subgroups (lineages) have been discerned with subtle within-lineage variation, permitting low-resolution classification of isolates. Because proteins, coding sequences, and especially antigen-coding genes have been used extensively in previous studies, we focused on sequence variation in introns of housekeeping genes, which may be more informative for phylogenetic analysis because they evolve under lower selection.

Detection of immunoglobulin M antibodies to P35 antigen of Toxoplasma gondii for serodiagnosis of recently acquired infection in pregnant women.

We examined the efficiency of detection of immunoglobulin M (IgM) antibodies to a 35-kDa antigen (P35) of Toxoplasma gondii for serodiagnosis of acute infection in pregnant women. A double-sandwich enzyme-linked immunosorbent assay (ELISA) with recombinant P35 antigen (P35-IgM-ELISA) was used for this purpose. On the basis of the clinical history and the combination of results from the toxoplasma serological profile (Sabin-Feldman dye test, conventional IgM and IgA ELISAs, and the differential agglutination test), the patients were classified into three groups: group I, status suggestive of recently acquired infection; group II, status suggestive of infection acquired in the distant past; group III, status suggestive of persisting IgM antibodies.

Serodiagnosis of recently acquired Toxoplasma gondii infection using an enzyme-linked immunosorbent assay with a combination of recombinant antigens.

An enzyme-linked immunosorbent assay (ELISA) using four recombinant antigens of Toxoplasma gondii (rP22, rP25, rP29, and rP35) was used in an attempt to differentiate pregnant women with toxoplasma serologic profiles (TSPs) indicative of recently acquired infections (acute profile) from those with TSPs indicative of infections acquired in the distant past (chronic profile). In general, immunoglobulin G antibodies in sera from women with the acute profile reacted more strongly with the recombinant antigens than did those in sera from women with the chronic profile. However, reactivities differed significantly between antigens that reacted with a single serum and between sera that reacted with a single antigen.

Induction of tumor necrosis factor-alpha and inducible nitric oxide synthase fails to prevent toxoplasmic encephalitis in the absence of interferon-gamma in genetically resistant BALB/c mice.

Following infection with Toxoplasma gondii, certain strains of mice, such as BALB/c, are genetically resistant to development of toxoplasmic encephalitis (TE) and establish a latent chronic infection as do humans. Thus, these animals appear to be a suitable model to analyze the mechanism of resistance to TE. Since the mechanism for their genetic resistance is unknown, we examined the role of interferon-gamma (IFN-gamma) tumor necrosis factor-alpha (TNF-alpha) and inducible nitric oxide synthase (iNOS) in the resistance using BALB/c-background IFN-gamma-deficient (IFN-gamma(-/-)) mice.

Use of recombinant antigens for detection of Toxoplasma gondii infection in swine.

Five recombinant Toxoplasma gondii antigens, designated B427, C51, C55, V22, and MBP30 were assessed for their potential use in an enzyme-linked immunoassay (EIA) for detection of T. gondii infection in swine. The antigens were evaluated with sera from young pigs that had been fed 1-10,000 T.

Serodiagnosis of recently acquired Toxoplasma gondii infection with a recombinant antigen.

A portion of a cDNA encoding a 35-kDa antigen from Toxoplasma gondii was cloned into the CKS expression vector and expressed in Escherichia coli. By using the enzyme-linked immunosorbent assay (ELISA), the recombinant protein (rP35 antigen) was examined for reactivity with immunoglobulin G (IgG) antibodies in the sera of pregnant women. Of these women, 41 had a toxoplasma serologic profile suggestive of recently acquired T.

Use of the polymerase chain reaction for diagnosis of ocular toxoplasmosis.

Objective: To report a cohort of patients in whom polymerase chain reaction (PCR) was performed on vitreous samples and to place in perspective the current role of PCR in the diagnosis of ocular toxoplasmosis.

Design: Noncomparative case series.

Participants: Fifteen patients in whom toxoplasmic retinochoroiditis was considered in the differential diagnosis and in whom the clinical presentation was not diagnostic and/or response to treatment was inadequate.

Expressed sequence tag analysis of the bradyzoite stage of Toxoplasma gondii: identification of developmentally regulated genes.

Toxoplasma gondii is a protozoan parasite responsible for widespread infections in humans and animals. Two major asexual forms are produced during the life cycle of this parasite: the rapidly dividing tachyzoite and the more slowly dividing, encysted bradyzoite. To further study the differentiation between these two forms, we have generated a large number of expressed sequence tags (ESTs) from both asexual stages.

Toxoplasma gondii expresses two distinct lactate dehydrogenase homologous genes during its life cycle in intermediate hosts.

Two Toxoplasma gondii genes were characterized that are differentially expressed during the parasite's life cycle. The genes named LDH1 and LDH2, respectively, encode polypeptides similar to the enzyme lactate dehydrogenase (LDH; L-lactate:NAD+ oxidoreductase, EC 1.1.

Use of a recombinant antigen, SAG2, expressed as a glutathione-S-transferase fusion protein to immunize mice against Toxoplasma gondii.

The capacity of Toxoplasma gondii surface protein SAG2 to induce protective immunity against the parasite in mice was studied using recombinant SAG2 expressed as a glutathione-S-transferase (GST) fusion protein incorporated into immune stimulating complexes (iscoms). Immunization with the iscoms resulted in the production of antibodies recognizing SAG2 as well as GST. After oral challenge infection with T.

An immunohistochemical method for detecting bradyzoite antigen (BAG5) in Toxoplasma gondii-infected tissues cross-reacts with a Neospora caninum bradyzoite antigen.

The previously cloned gene of a bradyzoite-specific antigen (BAG5) of Toxoplasma gondii was used to express a fusion protein for subsequent antiserum production in rabbits. The BAG5 antiserum was used in an immunohistochemical procedure to look for reactive epitopes in bradyzoites and tachyzoites of T. gondii within animal tissues.