Monoclonal antibodies against pertussis toxin subunits

Abstract Twenty monoclonal antibodies (mAbs) reacting with cholera toxin (CT) of Vibrio cholerae strain 569B were characterized in cross-section and G_M1 ganglioside inhibition assays. MAbs were characterized by reaction with CT and Escherichia coli heat-labile porcine strain (LT_p) and human strain (LTh) enterotoxins, and by G_M1 ganglioside inhibition of mAb binding. Eight of 10 CT-A specific and 3 of 10 CT-B-specific mAbs cross-reacted with LTh and LTp. G_M1 ganglioside inhibited reactions of the CT-B cross-reacting antibodies. Results showed that these epitodes common to the B subunit of CT and LT are located in or near the G_M1 ganglioside binding region, and that the G_M1 ganglioside-binding region of LT differs from that of CT.     

A comparison of the ability of forest and agricultural soils to mineralize chlorinated aromatic compounds

Soils were sampled from two agricultural fields, two relatively pristine forests, and one suburban forest in Ontario, Canada. The ability of these soils to mineralize 2,4-dichlorophenoxyacetate, 3-chlorobenzoate, 4-chlorophenol, 2,4-dichlorophenol, pentachlorophenol, and atrazine was determined using ¹⁴C-labeled substrates. Direct preexposure was necessary before atrazine mineralization could be detected; however, it was not necessary for degradation of any of the other chemicals. 2,4-dichlorophenoxyacetate and pentachlorophenol mineralization was much higher in the agricultural soils relative to the pristine forest soils, but 3-chlorobenzoate and 2,4-dichlorophenol mineralization rates showed the opposite trend. Mineralization of 4-chlorophenol was about equivalent in all soils. Suburban forests soils were indistinguishable from agricultural soils with respect to their degradation of 2,4-dichlorophenoxyacetate and chlorobenzoate. Additionally, they were better able than any of the soils to withstand the toxic effects of pentachlorophenol. Pentachlorophenol mineralization was highly variable in the pristine forest soils, ranging from about 6 to 50%. Abiotic factors such as pH, soil type, and organic and moisture content did not account for these significant site differences. The selective forces responsible for these differences, and the possible differences in microbial populations are discussed.     

Three different forms of hexokinase are identified during Tuber Borchii mycelium growth

Truffles are ectomycorrhizal fungi which have a great dependence on carbohydrates supplied by their host plants. The catabolism of hexoses in the mycobiont is important for the production of energy, and the first enzyme in the hexose assimilation pathways is hexokinase. This study reports differences in the expression of this enzyme during the growth of Tuber borchii Vittad. mycelium (strain ATCC 96540). Three hexokinase activities (HKM1, HKM2 and HKM3) were isolated by anion-exchange chromatography and partially purified. HKM1 and HKM2 were present in the linear phase at 15-50 days of growth. Two remarkable differences were found in the sugar-phosphorylating activity and stability of HKM1 and HKM2. HKM2 did not phosphorylate the fructose and it was present in the chromatographic profile only when substrates such as glucose, glucosamine or mannose were added to the extraction buffer. On the contrary, HKM1 utilized also fructose and was detected under all the experimental conditions used. HKM3 was the only molecular form observed after 70 days, when the fungus growth had reached a plateau. To our knowledge these results represent the first evidence for the presence in T. borchii mycelium of three distinct enzymatic forms of hexokinase which are differently expressed during growth of the fungus.     

Sleep patterns of day-working, evening high-schooled adolescents of São Paulo, Brazil

Children who grow up in developing countries of the world must work to help financially support their families, and they must also attend school. We investigated the impact of work on the sleep of working vs. nonworking high school students. Twenty-seven S?o Paulo, Brazil, public high school students (eight male and eight female working students plus six nonworking female and five nonworking male students) 14-18 yrs of age who attended school Monday-Friday between 19:00 to 22:30h participated. A comprehensive questionnaire about work and living conditions, health status, and diseases and their symptoms was also answered. The activity level and rest pattern (sleep at night and napping during the day) were continuously assessed by wrist actigraphy (Ambulatory Monitoring, USA). The main variables were analyzed by a two-factor ANOVA with application of the Tukey HSD test for multiple comparisons, and the length of sleep during weekdays vs. weekends was compared by Student t-test. Working students went to sleep earlier weekends [F(1,23)=6.1; p=0.02] and woke up earlier work days than nonworking students [F(1,23) = 17.3; p = 0.001]. The length of nighttime sleep during weekdays was shorter among all the working [F(1,23)= 16.7; p <0.001] than all the nonworking students. The sleep duration of boys was shorter than of girls during weekends [F(1,23)= 10.8; p <0.001]. During weekdays, the duration of napping by working and nonworking male students was shorter than nonworking female students. During weekdays working girls took the shortest naps [F(1,23)= 5.6; p = 0.03]. The most commonly reported sleep complaint during weekdays was difficulty waking up in the morning [F(1,23) = 6.5; p = 0.02]. During weekdays, the self-perceived sleep quality of working students was worse than nonworking students [F(1,23) = 6.2; p = 0.02]. The findings of this study show that work has negative effects on the sleep of adolescents, with the possible build-up of a chronic sleep debt with potential consequent impact on quality of life and school learning.     

Liposome-stabilized oil-in-water emulsions as adjuvants: increased emulsion stability promotes induction of cytotoxic T lymphocytes against an HIV envelope antigen

Protective or therapeutic immunity against HIV infection is currently believed to require both antibody and CTL responses against the envelope protein. In the present study, the adjuvant activity of a unique oil-in-water emulsion, in which liposomes containing lipid A (LA) and encapsulated antigen served as the emulsifying agent, was examined in mice using oligomeric gp140 (ogp140) derived from the HIV-1 envelope as the antigen. Emulsions rendered either highly stable or unstable by altering the ratio of liposomes to oil were used to examine the effect of stability of the emulsion on adjuvant activity. Stable and unstable emulsions had similar potencies for inducing both IgG antibodies to ogp140 and antigen-specific T-lymphocyte proliferation. Stable emulsions, but not unstable emulsions, induced antigen-specific CTL responses, possibly because of the depot effect of the stable emulsions. Furthermore, stable emulsions induced lower IgG2a/IgG1 ratios than the unstable emulsions. We conclude that stable liposomal oil-in-water emulsions provide an effective means of obtaining both antibody and CTL responses against an HIV envelope antigen.     

Molecular mechanisms in prostate cancer. A review

Genetic studies have provided remarkable clues to the causes of prostate cancer (PCa). For example, in addition to the expected role of androgens in facilitating the development of PCa, the possibility that infections might lead to prostate cancer has been raised with the identification of RNASEL and MSR1 as familial prostate cancer genes; that insight will profoundly affect future studies and may ultimately lead to new approaches to the prevention of prostate cancer. The identification of key molecular alterations in prostate cancer cells implicates carcinogen defenses, including GSTP1, growth factor signaling pathways (such as NKX3.1, PTEN and p27) and androgens as critical determinants of the phenotype of PCa cells and defines specific targets for detection, diagnosis and treatment of PCa.     

The use of the polymerase chain reaction and restriction fragment length polymorphism technique associated with the classical morphology for characterization of Lymnaea columella, L. viatrix, and L. diaphana (Mollusca: Lymnaeidae)

The specific identification of Lymnaeid snails is based on a comparison of morphological characters of the shell, radula, renal and reproductive organs. However, the identification is complicated by dissection process, intra and interspecific similarity and variability of morphological characters. In the present study, polymerase chain reaction and restriction fragment length polymorphism (PCR-RFLP) techniques targeted to the first and second internal transcribed spacers (ITS1 and ITS2) rDNA and to the mitochondrial 16S ribosomal gene (16S rDNAmt) were used to differentiate the species Lymnaea columella, L. viatrix, and L. diaphana from some localities of Brazil, Argentina, and Uruguay as well as to verify whether the molecular results corroborates the classical morphological method.PCR-RFLP analysis of the ITS1, ITS2, and 16S using 12 restriction enzymes revealed characteristic patterns for L. columella and L. diaphana which were concordant with the classical morphology. On the other hand, for L. viatrix populations a number of 1 to 6 profiles were generated while morphology provided the species pattern results.