Distinction between plant samples according to allele dosage by semiquantitative polymerase chain reaction

The lack of informativity of samples from heterozygotic individuals is one of the hindrances in the mapping of quantitative trait loci of outbred populations, since it is not normally possible to identify the origin of each allele. One way to include these individuals in analyses would be to genotype their endosperm, considering that a heterozygote (Aa) has AAa or Aaa endosperm, when the female genitor donates the A or a allele, respectively. We used semiquantitative polymerase chain reaction to determine allele dosages in DNA mixtures, by simulating the observed conditions for endospermic tissue. Semiquantitative polymerase chain reaction on agarose gels, along with regression analysis, allowed differentiation of the samples according to the amount of DNA. This type of information will help decrease the number of non-informative individuals in quantitative trait locus mapping of outbred populations, thereby increasing mapping accuracy.

Integrated monitoring of South Portugal water bodies: a methodology towards WFD

The challenge on implementation of the EU Water Framework Directive (WFD) (2000/60/EC) fosters the development of new monitoring approaches. The directive promotes the use of modelling techniques to assist all phases of the process, from characterization and establishment of reference conditions to identification of pressures and assessment of impact. This work is based on the above principles. A classical monitoring of the water status of the main transitional water bodies of Algarve (South of Portugal) is combined with advanced in situ water profiling and hydrodynamic, water quality and ecological modelling to build a complete description of the system. The aim is to demonstrate a methodology where traditional monitoring and modelling tools can be joined together to draw a holistic picture. The results show that globally the water bodies present a good trophic status. Eutrophication symptoms are not generalized. Due to physical transport and dispersion, nutrient enrichment is not the only factor limiting growth; residence time is also an important factor. Some confined regions with high residence times are at present endangered by point and diffuse sources of pollution. The microbiologic impact of waste water treatment plants (WWTP) is confined to regions between 500 m and 1 km from the discharges.

Flow cytometric determination of cellular sources and frequencies of key cytokine-producing lymphocytes directed against recombinant LACK and soluble Leishmania antigen in human cutaneous leishmaniasis

Leishmaniasis, caused by infection with the protozoan parasite Leishmania, affects millions of individuals worldwide, causing serious morbidity and mortality. This study directly determined the frequency of cells producing key immunoregulatory cytokines in response to the recombinant antigen Leishmania homolog of receptors for activated kinase C (LACK) and soluble leishmania antigen (SLA), and it determined relative contributions of these antigens to the overall cytokine profile in individuals infected for the first time with Leishmania braziliensis. All individuals presented with the cutaneous clinical form of leishmaniasis and were analyzed for proliferative responses to LACK antigen and SLA, frequency of lymphocyte subpopulations (analyzed ex vivo), and antigen-induced (LACK and SLA) cytokine production at the single-cell level (determined by flow cytometry). The following were determined. (i) The Th1-type response previously seen in patients with cutaneous leishmaniasis is due to gamma interferon (IFN-gamma) production by several different sources, listed in order of contribution: CD4(+) T lymphocytes, CD4(-), CD8(-) lymphocytes, and CD8(+) T lymphocytes. (ii) SLA induced a higher frequency of lymphocytes producing IFN-gamma and tumor necrosis factor alpha (TNF-alpha) than did LACK. (iii) LACK induced an activation of monocyte populations as reflected by an increased percentage of CD14-positive cells. (iv) Neither SLA nor LACK induced detectable frequencies of cells producing interleukin-4 (IL-4) or IL-5. These data demonstrated a multifaceted immune response to SLA in human leishmaniasis involving Th1 CD4(+) T lymphocytes (IFN-gamma(+) and IL-10(-)/IL-4(-)), Tc1 CD8(+) T cells (IFN-gamma(+), and IL-10(-)/IL-4(-)), and a high frequency of TNF-alpha-producing lymphocytes. Moreover, it was determined that the recombinant antigen LACK acts as a weak inducer of Th1-type lymphocyte responses compared to SLA.