RESUMO Objetivou-se com este trabalho verificar biometria de parte aérea, rendimento de aquênios de plantas de girassol sobre o efeito de doses crescentes de resíduo de sangue, como fonte alternativa de fósforo (P), em um Latossolo vermelho de textura argilosa. O delineamento experimento utilizado foi o de blocos casualizados, com seis tratamentos e quatro repetições. Os tratamentos foram constituídos por cinco doses de resíduo de sangue (0, 6, 12, 24 e 48m3 ha-1) e um tratamento que recebeu a adubação fosfatada química, 80kg ha-1 de P2O5. As doses crescentes de resíduo de sangue e adubação química não demostram desproporcionalidade para a concentração de P no solo, folha, altura de planta (AP), diâmetro de caule (DC), diâmetro de capítulo (DCP) e produção de aquênios. A análise de componentes (CP) principais revelou que o primeiro CP apresenta maior variação acumulada (74%). Baseado no primeiro CP, a dose de 12 m-3 ha-1exibe maior influência para AP, DC e DCP. Devido a maior influência sobre as características biométricas em plantas de girassol, o resíduo de sangue (12m-3 ha-1 = 98,4kg P ha-1), pode ser utilizado como fonte alternativa de fósforo para o cultivo de girassol em Latossolos de textura argilosa.

ABSTRACT The aim of this work was to increase the aerial part, biometry, and yield of achenes from sunflower plants on the effect of increasing doses of blood residue, as an alternative source of phosphorus (P), in a clayey-textured red Oxisol. The experimental design used was randomized blocks, with six treatments and four replications. The treatments consisted of five doses of blood residue (0, 6, 12, 24 and 48m3 ha-1) and a control treatment that received phosphate chemical fertilization, 80kg ha-1 of P2O5. The increasing doses of blood residue and chemical fertilization do not show disproportionality for P concentration in soil, leaf, plant height (PH), stem diameter (SD), chapter diameter (CD) and achene production. The analysis of the principal component (PC) revealed that the first PC presents the greatest accumulated variation (74%). Based on the first PC, the dose of 12m-3 ha-1 has greater influence for PH, SC, and CD. Due to the greater influence on the biometric characteristics of sunflower plants, the blood residue (12m-3 ha-1 = 98.4kg P ha-1), can be used as an alternative source of phosphorus for the cultivation of sunflower in clayey oxisols.

Although Helicobacter heilmannii infection is less common than H. pylori infection in humans, it is considered to be of medical importance because of its association with gastritis, gastric ulcer, carcinoma, and mucosa-associated lymphoid tissue lymphoma of the stomach. However, there have been no studies evaluating the role of the Th cell response in H. heilmannii gastric infection. We evaluated the participation of pro-inflammatory and anti-inflammatory cytokines, IFN-gamma and IL-4, in H. heilmannii gastric infection in genetically IFN-gamma- or IL-4-deficient mice. The serum IFN-gamma and IL-4 concentrations were determined by ELISA. The gastric polymorphonuclear infiltrate was higher (P = 0.007) in H. heilmannii-positive than in H. heilmannii-negative wild-type (WT) C57BL/6 mice, whereas no significant inflammation was demonstrable in the stomach of H. heilmannii-positive IFN-gamma-/- C57BL/6 mice. The degree of gastric inflammatory cells, especially in oxyntic mucosa, was also higher (P = 0.007) in infected IL-4-/- than in WT BALB/c mice. Serum IFN-gamma levels were significantly higher in IL-4-/- than in WT BALB/c mice, independently of H. heilmannii-positive or -negative status. Although no difference in serum IFN-gamma levels was seen between H. heilmannii-positive (11.3 ± 3.07 pg/mL, mean ± SD) and -negative (11.07 ± 3.5 pg/mL) WT BALB/c mice, in the group of IL-4-/- animals, the serum concentration of IFN-g was significantly higher in the infected ones (38.16 ± 10.5 pg/mL, P = 0.04). In contrast, serum IL-4 levels were significantly decreased in H. heilmannii-positive (N = 10) WT BALB/c animals compared to the negative (N = 10) animals. In conclusion, H. heilmannii infection induces a predominantly Th1 immune response, with IFN-gamma playing a central role in gastric inflammation.

Probiotics are formulations containing live microorganisms or microbial stimulants that have some beneficial influence on the maintenance of a balanced intestinal microbiota and on the resistance to infections. The search for probiotics to be used in prevention or treatment of enteric infections, as an alternative to antibiotic therapy, has gained significant impulse in the last few years. Several studies have demonstrated the beneficial effects of lactic acid bacteria in controlling infection by intestinal pathogens and in boosting the host's nonspecific immune response. Here, we studied the use of Lactobacillus acidophilus UFV-H2b20, a lactic acid bacterium isolated from a human newborn from Viçosa, Minas Gerais, Brazil, as a probiotic. A suspension containing 108 cells of Lactobacillus acidophilus UFV-H2b20 was inoculated into groups of at least five conventional and germfree Swiss mice to determine its capacity to stimulate the host mononuclear phagocytic activity. We demonstrate that this strain can survive the stressing conditions of the intestinal tract in vivo. Moreover, the monoassociation of germfree mice with this strain for seven days improved the host's macrophage phagocytic capacity, as demonstrated by the clearance of a Gram-negative bacterium inoculated intravenously. Monoassociated mice showed an undetectable number of circulating E. coli, while 0.1% of the original inoculum was still present in germfree animals. Mice treated with viable or heat-killed Lactobacillus acidophilus UFV-H2b20 presented similarly improved clearance capacity when compared with germfree controls. In addition, monoassociated mice had twice the amount of Kupffer cells, which are responsible for the clearance of circulating bacteria, compared to germfree controls. These results suggest that the L. acidophilus strain used here stimulates a nonspecific immune response and is a strong candidate to be used as a probiotic.

Toxoplasma gondii and Trypanosoma cruzi are intracellular parasites which, as part of their life cycle, induce a potent cell-mediated immunity (CMI) maintained by Th1 lymphocytes and IFN-<FONT FACE="Symbol">g</font>. In both cases, induction of a strong CMI is thought to protect the host against rapid parasite multiplication and consequent pathology and lethality during the acute phase of infection. However, the parasitic infection is not eliminated by the immune system and the vertebrate host serves as a parasite reservoir. In contrast, Leishmania sp, which is a slow growing parasite, appears to evade induction of CMI during early stages of infection as a strategy for surviving in a hostile environment (i.e., inside the macrophages which are their obligatory niche in the vertebrate host). Recent reports show that the initiation of IL-12 synthesis by macrophages during these parasitic infections is a key event in regulating CMI and disease outcome. The studies reviewed here indicate that activation/inhibition of distinct signaling pathways and certain macrophage functions by intracellular protozoa are important events in inducing/modulating the immune response of their vertebrate hosts, allowing parasite and host survival and therefore maintaining parasite life cycles.

The association of vertebrate hosts with the indigenous microbiota and its effect on the response to infections has long been a subject of scientific curiosity. From the first theory supported by Louis Pasteur that life would be impossible in the absence of associated microorganisms to the development of germfree mammals for research, a lot was learned about how the normal microbiota influences the environment in which pathogens may find themselves. In the present review, we attempt to summarize the more recent results from our group and others on the influence of the normal microbiota on the outcome of parasitic infections. Our results and those of others point to a complex relationship between the mammalian system and its indigenous microbiota, leading to greater resistance to some infections and enhanced susceptibility to others