A Mycobacterium leprae-specific human T cell epitope cross-reactive with an HLA-DR2 peptide

Mycobacterium leprae induces T cell reactivity and protective immunity in the majority of exposed individuals, but the minority that develop leprosy exhibit various types of immunopathology. Thus, the definition of epitopes on M. leprae antigens that are recognized by T cells from different individuals might result in the development of an effective vaccine against leprosy. A sequence from the 65-kD protein of this organism was recognized by two HLA-DR2-restricted, M. leprae-specific helper T cell clones that were derived from a tuberculoid leprosy patient. Synthetic peptides were used to define this epitope as Leu-Gln-Ala-Ala-Pro-Ala-Leu-Asp-Lys-Leu. A similar peptide that was derived from the third hypervariable region of the HLA-DR2 chain, Glu-Gln-Ala-Arg-Ala-Ala-Val-Asp-Thr-Tyr, also activated the same clones. The unexpected cross-reactivity of this M. leprae-specific DR2-restricted T cell epitope with a DR2 peptide may have to be considered in the design of subunit vaccines against leprosy.     

Influences on fermentation and thiamine metabolism in bovine rumen fluid (in vitro)--part 3: Effects of artificially contaminated hay with Cladosporium herbarum and Fusarium graminearum, respectively

The influence of contaminated hay [Cladosporium herbarum (CL) and Fusarium graminearum (FU), respectively] on fermentation and thiamine metabolism of bovine rumen content was investigated using the longterm rumen simulation technique (RUSITEC). Six investigation periods 25 days long each were carried out. A nine days feeding period with normal hay was followed by the testphase I (five days) with a mixture of normal and mouldy hay and testphase II (five days) with additive an 0.3 mg thiamine per reaction vessel. The last four days served as regeneration time with normal hay. The following marginal effects of mouldy hay on rumen fermentation patterns could be noted. A) During testphase I: cellulase activity: +10.0% (FU); alternation of the thiamine derivate pattern, but no effect on total thiamine content (CL, FU). B) During testphase II the results were more obvious: bacterial protein synthesis: -22.6% (CL), -24.4% (FU). Alternation of the fatty acid pattern: propionate (-7.30% FU), n-butyrate (-3.90% CL, +3.49% FU), n-valerate (-8.5% CH, FU). Cellulase activity: -17.0% (CL, FU). But no effect on total thiamine (CL, FU); alternation of the thiamine derivate pattern: more non phosphorylate thiamine. The noted effects on rumen fermentation and thiamine metabolism were not severe enough to be responsible for the development of a CCN.     

Relation of milk production loss to milk somatic cell count.

Milk production loss was studied in relation to increased somatic cell count (SCC). Available data were weekly test-day milk yields and SCC (in 1,000 cells/ml), and mastitis incidences. In total, 18,131 records from 274 cows were used. Production loss was determined for test-day kg milk, kg protein, and kg energy-corrected milk. Least-squares analysis of variance was used to estimate the direct effect of Log10(SCC) on production. The recorded measures of production were first corrected for fixed effects, with adjustment factors estimated from a healthy data-set. The average daily milk yield was 19.7 kg/day in first lactation and 22.0 in later lactations. The geometric mean of SCC was 63.1 in first lactation and 107.2 in later lactations. The incidence of clinical mastitis treated by a veterinarian was 19.8% of the lactations-at-risk. Linear relationships were found between the production parameters and Log10(SCC). Quadratic and cubic effects were evaluated, but were found to contribute little to the overall fit of the models. The individual milk yield loss was 1.29 kg/day for each unit increase in Log10(SCC) for cows in first lactation. Milk yield decreased by 2.04 kg/day per unit Log10(SCC) for older cows. Corresponding values for protein yield were 0.042 and 0.067 kg/day for first and later lactations, respectively.     

Macrobenthic biodiversity and oxygen uptake in estuarine systems: the example of the Seine estuary

Purpose

Bioturbation is a major process influencing the functioning of benthic ecosystems. Although controlled experiments with species in monoculture or in artificial combinations have increased the knowledge about the role of biological diversity on geochemical processes, specific interactions have been neglected, making the extrapolation of experimental results to natural systems difficult. In this context, the main objective of this study was to measure the effects of a whole natural macrobenthic community on benthic oxygen uptake.

Materials and methods

The relationships between macrofauna and oxygen uptakes were investigated in the estuarine system of the Seine, France, during the winter and fall according to the variability of river discharge. Four undisturbed sediment cores with associated macrofauna and overlying water were sampled at nine subtidal stations in order to perform whole core incubations and measure total oxygen uptake (TOU). Moreover, values of diffusive oxygen uptake (DOU) were obtained using microelectrode profiling and fauna-mediated oxygen uptake (FOU) was calculated as the difference between TOU and DOU. FOUs were thus linked to macrofaunal parameters; both traditional (species richness, abundance and biomass) and functional (trophic guilds and bioturbation modes).

Results and discussion

The average FOU (±SD) ranged from 170?±?36 to 1,324?±?701???mol?m^?2?h^?1, and values represented 33 to 89?% of TOU. Each of the traditional macrofauna parameters had a significant and positive correlation with FOU. In addition, abundance, biomass and species number of some functional groups (e.g. suspension feeders and biodiffusors) were also correlated to FOU, supporting the diversity?Cstability hypothesis of McArthur (Ecology 36:533?C536, 1955). Nevertheless, the relationship between FOU and other functional groups such as conveyors illustrated the idiosyncratic nature of this hypothesis, underlining the difficulty of clearly identifying the role of a macrofaunal community on oxygen exchanges at the sediment?Cwater interface.

Conclusions

Our results confirm the importance of functional biodiversity on mineralization processes as well as the need to take into account the whole community. They also suggest that future studies should focus on the functional consequences of species loss and the potential resilience of the communities as a way to maintain ecosystem processes.     

Adaptation of fruit morphology to dispersal agents in a neotropical forest

Two-thirds of 258 fruit species from Peruvian tropical forest belong to one of two classes: large orange, yellow, brown, or green fruits with a husk; or small red, black, white, blue, purple, or mixed-color fruits without a husk. The characteristics of the two fruit classes match the size, visual ability, and jaw morphology of mammals and birds, respectively, and the animals also prefer to eat one class of fruits. Thus, most plants in this forest seem to be adapted to seed dispersal by either of two distinct broad arrays of animal taxa.     

A reproductive calendar of Lilium longiflorum Thunb. cv. Gelria

Summary The development and timing of different processes in the floral biology and sexual reproduction of Lilium longiflorum were studied and brought together into a chronological reproductive calendar. Care must be taken when emasculating flowers later than 4 days before anthesis (DBA), because the stomium of the anther was open from 8 DBA and the pollen grains appear to be mature from 3–2 DBA. The receptivity period of the pistil lasts for a rather long period, but before wilting of an unpollinated flower as determined by a change of the colour of the perianth from white into brown, the flower had already lost its receptivity. Because L. longiflorum pollen grains can easily be stored, the pistil receptivity should thus determine the pollination schedule. The relationships between pollen tubes and pistil are discussed with respect to plant breeding.Abbreviations DAA Days After Anthesis - DAP Days After Pollination - DBA Days Before Anthesis     

Equine serum lipids: serum lipids and glucose in Morgan and Thoroughbred horses and Shetland ponies.

Concentrations of serum phospholipids, triglycerides, total cholesterol, nonesterified fatty acids, and glucose were determined for 9 months (September, 1972, to May, 1973) in 19 fasting horses and ponies (8 Morgan horses, 7 Thoroughbred horses, and 4 Shetland Ponies). Morgan horses had higher concentrations of total lipid than did Thoroughbreds, although the relative proportions of each type of lipid were similar in the 2 breeds. Shetland Ponies had higher nonesterified fatty acid and lower glucose concentrations than did either breed of horse. In both breeds of horses, concentrations of serum triglycerides in the cold months (December to March) were lower than those in the warm months. In the Shetland Pony, there was no seasonal variation in triglycerides, but a significant increase was seen in concentration of nonesterified fatty acids in the cold months. The significance of these findings is discussed.