Gambiense Human African Trypanosomiasis and Immunological Memory: Effect on Phenotypic Lymphocyte Profiles and Humoral Immunity

In mice, experimental infection with Trypanosoma brucei causes decreased bone marrow B-cell development, abolished splenic B-cell maturation and loss of antibody mediated protection including vaccine induced memory responses. Nothing is known about this phenomenon in human African trypanosomiasis (HAT), but if occurring, it would imply the need of revaccination of HAT patients after therapy and abolish hope for a HAT vaccine. The effect of gambiense HAT on peripheral blood memory T- and B-cells and on innate and vaccine induced antibody levels was examined. The percentage of memory B- and T-cells was quantified in peripheral blood, prospectively collected in DR Congo from 117 Trypanosoma brucei gambiense infected HAT patients before and six months after treatment and 117 controls at the same time points. Antibodies against carbohydrate antigens on red blood cells and against measles were quantified. Before treatment, significantly higher percentages of memory B-cells, mainly T-independent memory B-cells, were observed in HAT patients compared to controls (CD20+CD27+IgM+, 13.0% versus 2.0%, p<0.001). The percentage of memory T-cells, mainly early effector/memory T-cells, was higher in HAT (CD3+CD45RO+CD27+, 19.4% versus 16.7%, p = 0.003). After treatment, the percentage of memory T-cells normalized, the percentage of memory B-cells did not. The median anti-red blood cell carbohydrate IgM level was one titer lower in HAT patients than in controls (p<0.004), and partially normalized after treatment. Anti-measles antibody concentrations were lower in HAT patients than in controls (medians of 1500 versus 2250 mIU/ml, p = 0.02), and remained so after treatment, but were above the cut-off level assumed to provide protection in 94.8% of HAT patients, before and after treatment (versus 98.3% of controls, p = 0.3). Although functionality of the B-cells was not verified, the results suggest that immunity was conserved in T.b. gambiense infected HAT patients and that B-cell dysfunction might not be that severe as in mouse models.     

Isolation identification and biochemical characterization of a novel halo-tolerant lipase from the metagenome of the marine sponge Haliclona simulans

ABSTRACT: BACKGROUND: Lipases (EC 3.1.1.3) catalyze the hydrolysis of triacyl glycerol to glycerol and are involved in the synthesis of both short chain and long chain acylglycerols. They are widely used industrially in various applications, such as baking, laundry detergents and as biocatalysts in alternative energy strategies. Marine ecosystems are known to represent a large reservoir of biodiversity with respect to industrially useful enzymes. However the vast majority of microorganisms within these ecosystems are not readily culturable. Functional metagenomic based approaches provide a solution to this problem by facilitating the identification of novel enzymes such as the halo-tolerant lipase identified in this study from a marine sponge metagenome. RESULTS: A metagenomic library was constructed from the marine sponge Haliclona simulans in the pCC1fos vector, containing approximately 48,000 fosmid clones. High throughput plate screening on 1% tributyrin agar resulted in the identification of 58 positive lipase clones. Following sequence analysis of the 10 most highly active fosmid clones the pCC1fos53E1 clone was found to contain a putative lipase gene lpc53E1, encoded by 387 amino acids and with a predicted molecular mass of 41.87 kDa. Sequence analysis of the predicted amino acid sequence of Lpc53E1 revealed that it is a member of the group VIII family of lipases possessing the SXTK motif, related to type C beta-lactamases. Heterologous expression of lpc53E1 in E. coli and the subsequent biochemical characterization of the recombinant protein, showed an enzyme with the highest substrate specificity for long chain fatty acyl esters. Optimal activity was observed with p- nitrophenyl palmitate (C16) at 40degreesC, in the presence of 5 M NaCl at pH 7; while in addition the recombinant enzyme displayed activity across broad pH (3-12) and temperature (4 -60degreesC) ranges and high levels of stability in the presence of various solvents at NaCl concentrations as high as 5 M and at temperatures ranging from 10 to 80degreesC. A maximum lipase activity of 2,700 U/mg was observed with 10 mM p-nitrophenyl palmitate as substrate, in the presence of 5 mM Ca 2+ and 5 M NaCl, and a reaction time of 15 min at pH 7 and 40degreesC; while KM and Vmax values were calculated to be 1.093 mM-1and 50 umol/min, respectively. CONCLUSION: We have isolated a novel halo tolerant lipase following a functional screen of a marine sponge fosmid metagenomic library. The activity and stability profile of the recombinant enzyme over a wide range of salinity, pH and temperature; and in the presence of organic solvent and metal ions suggests a utility for this enzyme in a variety of industrial applications.     

Human African Trypanosomiasis Diagnosis in First-Line Health Services of Endemic Countries,a Systematic Review

While the incidence of Human African Trypanosomiasis (HAT) is decreasing, the control approach is shifting from active population screening by mobile teams to passive case detection in primary care centers. We conducted a systematic review of the literature between 1970 and 2011 to assess which diagnostic tools are most suitable for use in first-line health facilities in endemic countries. Our search retrieved 16 different screening and confirmation tests for HAT. The thermostable format of the Card Agglutination Test for Trypanosomiasis (CATT test) was the most appropriate screening test. Lateral flow antibody detection tests could become alternative screening tests in the near future. Confirmation of HAT diagnosis still depends on visualizing the parasite in direct microscopy. All other currently available confirmation tests are either technically too demanding and/or lack sensitivity and thus rather inappropriate for use at health center level. Novel applications of molecular tests may have potential for use at district hospital level.     

Taxonomic and biological notes on a species of Iphitime (Polychaeta, Eunicida) associated with Pagurus prideaux from western Norway

On the basis of 658 specimens collected over an 11 year period, the symbiotic eunicid polychaete, Iphitime paguri Fage & Legendre, 1934, is redescribed, and its biology in its presumed preferred host, Pagurus prideaux Leach, 1815, is outlined. The main ecological part is based on sampling of Pagurus on five occasions throughout a year in Raunefjorden, southwest of Bergen. Iphitime paguri turned out to have a strong sexual dimorphism, both in outer appearance and in the morphology of the jaws. Both juveniles and mature individuals of both genders are described. The infestation rate of Pagurus prideaux was very high (as opposed to the low reported infestation rate in Pagurus bernhardus, generally regarded as the host of this species) and the symbiotic polychaetes turned out to have a distinct pattern of host utilization in different life stages. Ripe males and females were, at certain times of the year, generally found more or less intertwined in the apex of the gastropod shell inhabited by its host. Small larval stages were found in the same place. Intermediate size groups were found in the gill chamber and in a sulcus on the carapax of the pagurid host.     

Clinical mastitis in ewes; bacteriology,epidemiology and clinical features

Background  

Clinical mastitis is an important disease in sheep. The objective of this work was to identify causal bacteria and study certain epidemiological and clinical features of clinical mastitis in ewes kept for meat and wool production.     

Growth and sex ratio of nestlings in two species of crows: how important is hatching asynchrony?

Summary In experimental studies of avian hatching paterns offspring sex has been neglected. This may be a problem if nestling growth and mortality is sex biased, and if this bias is influenced by hatching spread. In a field study of two crow species, the magpie Pica pica and the hooded crow Corvus corone cornix, we manipulated hatching spread. Both species have asynchronous hatching, and adult males are larger than females by 12–14%. The sex ratios obtained from the different experimental groups on day 24 post-hatch (total sample n = 403) did not deviate significantly from unity, nor did the sex ratios obtained among young newly hatched in an incubator (total sample n = 305). Male and female offspring were of similar size at hatching but males were larger on day 24 post-hatch. Males seemed to be more costly to rear than females, judging by the 20% difference in the mean amounts of food found in the gizzards of the young on day 24 post-hatch. Dimorphism in body size did not seem to be influenced by degree of hatching spread. Asynchronous hatching did not seem to be needed to produce high quality offspring of the larger sex (i.e. males), nor did asynchronous hatching help to ensure equal parental investment in male and female progeny. One reason for the latter negative results may be that the size dimorphism of the two crow species studied were relatively small.