Light intensity preference of juvenile pikeperch Sander lucioperca (L.)

Light intensity preference of the pikeperch was tested in 1-m(2) tanks divided into four lateral compartments with a hole in the middle to allow the fish to move between compartments. Two experiments were carried out with both 0+ and 1+ pikeperch: one testing intensities from 25 to 300 lx and the other from 1 to 50 lx. Light preference was observed individually for 5 days at 8, 11, 14 and 17 h. on the first and fifth day, the preference was tested without differences in light intensity (control). In both experiments, both age groups showed preference for the lowest available light intensity. Preference for low light intensity in pikeperch may be related to innate activity and feeding behaviour and to avoidance of harmful effects of light. It is suggested that under aquaculture operations, pikeperch should be reared under very dim conditions.

Combinatorial synthesis and directed evolution applied to the production of alpha-helix forming antimicrobial peptides analogues

Antimicrobial peptides (AMPs) are effector molecules of innate immune systems found in different groups of organisms, including microorganisms, plants, insects, amphibians and humans. These peptides exhibit several structural motifs but the most abundant AMPs assume an amphipathic alpha-helical structure. The alpha-helix forming antimicrobial peptides are excellent candidates for protein engineering leading to an optimization of their biological activity and target specificity. Nowadays several approaches are available and this review deals with the use of combinatorial synthesis and directed evolution in order to provide a high-throughput source of antimicrobial peptides analogues with enhanced lytic activity and specificity.

Analysis of the inflammatory reaction induced by the catfish (Cathorops spixii) venoms

Cathorops spixii is one of the most abundant venomous fish of the southeastern coast of the State of São Paulo, and consequently causes a great part of the accidents seen there. The accidents affect mainly fishermen, swimmers and tourists and are characterized by punctiform or wide wounds, erythema, edema, pain, sudoresis, indisposition, fever, nausea, vomiting and secondary infection. The objective of this work was to characterize the inflammatory response induced in mice by both venoms (mucus and sting) of the catfish C spixii. Our results demonstrated that both venoms induced a great number of rolling and adherent leukocytes in the post-capillary venules of cremaster muscle of mice, and an increase in the vascular permeability in peritoneal cavity. Mucus induced the recruitment of neutrophils immediately after injection followed later by macrophage infiltration. In contrast, the cellular infiltration elicited by sting venom was rapidly resolved. The peritonitis reaction provoked by venoms was characterized by cytokine (IL-6), chemokines (MCP-1 and KC) or lipid mediator (LTB4) production in the peritoneal cavity. The macrophages from 7-day mucus venom-induced exudates upon in vitro mucus venom stimulation, expressed CD1 Ic x MHC class II and release bioactive IL-12p70. on the other hand, sting venom-elicited peritoneal macrophages lost the ability to differentiate into dendritic cells, following re-stimulation in vitro with sting venom, they do not express CD11c, nor do they exhibit sufficient levels of MHC class II. In conclusion, both types of venoms (mucus or sting) promote inflammatory reaction with different profiles, and the inflammatory reaction induced by the first was characterized by antigen persistence in peritoneal cavity that allowed the activation of phagocytic cells with capacity of antigenic presentation. (C) 2007 Elsevier Ltd. All rights reserved.

Nitric oxide production in blowfly hemolymph after yeast inoculation

Although insects lack the adaptive immune response of the mammalians, they manifest effective innate immune responses that include both cellular and humoral components. Cellular responses are mediated by hemocytes and Immoral responses include the activation of proteolytic cascades that initiate many events, including NO production. In this work, we determined NO production in Chrysomya megaccphala hemolymph and hemocytes after yeast inoculation. Assays were performed with non-infected controls (NIL), saline-injected larvae (SIL) or larvae injected with Saccharomyces cerevisiae (YIL). The hemolymph of injected groups was collected 0.5, 1, 2, 4, 12, 24 or 48 h post-injection. NO levels in SIL were comparable to those measured in NIL until 12 h, which might be considered the basal production, increasing at 24 and 48 h post-injection, probably in response to the increased larval fragility after cuticle rupture. YIL exhibited significantly higher levels of NO than were found in other groups, peaking at 24 h. L-NAME and EDTA caused a significant reduction of NO production in YIL at this time, suggesting the activity of a Ca2+ -dependent NOS. Plasmatocytes and granular cells phagocytosed the yeasts. Plasmatocytes initiated the nodule formation and granular cells were the only hemocyte type to produce NO. These results permit us to conclude that yeasts induced augmented NO production in C. megacephala hemolymph and granular cells are the hemocyte type involved with the generation of this molecule. (c) 2005 Elsevier B.V. All rights reserved.

Mast cells in the eyes of Calomys callosus (Rodentia : Cricetidae) infected by Toxoplasma gondii

The mast cell is a powerful effector cell for the innate immune system, acting through the secretion of several distinct mediators. Few studies have demonstrated the relationship between mast cells and toxoplasmosis. In this study, mast cells were investigated in two experimental Toxoplasma infections using Calomys callosus (Rodentia: Cricetidae) as the host. Animals were inoculated either intraperitoneally or via the conjunctiva with tachyzoites of Toxoplasma gondii (RH strain) and sacrificed after 5 days or 24 h, respectively. Enucleated eyes were processed for histological and ultrastructural analysis. Neither experimental infection altered the localization of mast cells compared to control eyes, but they did lead to an accumulation in some tissues as well as to their activation. There was a significant increase in the number of mast cells within 5 days and 24 h after infection. The ocular lesions were characterized by the presence of tachyzoites, inflammatory cells and vasodilatation in the iris and retina. In conclusion, mast cells were mobilized in these experimental infections, suggesting that they play an important role in the host inflammatory response after infection with T. gondii.

Heat-killed Enterococcus faecalis Alters Nitric Oxide and CXCL12 Production but not CXCL8 and CCL3 Production by Cultured Human Dental Pulp Fibroblasts

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Morphological and quantitative aspects of nodule formation in hemolymph of the blowfly Chrysomya megacephala (Fabricius, 1794)

Insects manifest effective immune responses that include both cellular and humoral components. Morphological and quantitative aspects of cellular and Immoral cooperation during nodule formation in Chrysomya megacephala hemolymph against Saccharomyces cerevisae yeast cells were demonstrated for the first time. The analyses were performed in non-injected larvae (NIL), saline-injected larvae (SIL) and yeast-injected larvae (YIL). The hemolymph of injected groups was collected 0.5, 1, 2, 4, 12, 24, 36, or 48-h post-injection. Morphological aspects of YIL nodulation were investigated using transmission electron microscopy (TEM). Quantitative analyses consisted of total (THC) and differential hemocyte counts (DHC) in all the groups and total yeast count (TYC) in YIL, which were performed in an improved Neubauer chamber. Nodule formation was initiated at approximately 2-h post-injection. Twelve hours after the injection, TEM revealed the presence of an amorphous membrane, at the same time that circulating hemocyte number decreased significantly contrasting the increase of yeast number. Our results showed the ability of C megacephala hemolymph to perform humoral encapsulation when hemocyte population is insufficient to eliminate the microorganisms, warranting consideration in future investigations on the relative roles played by cellular and humoral elements of innate immunity of this calliphorid. (c) 2007 Elsevier B.V. All rights reserved.

Interactions between TLR2, TLR4, and mannose receptors with gp43 from Paracoccidioides brasiliensis induce cytokine production by human monocytes

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Tabelas de esperança de vida e fertilidade para Lipaphis erysimi (Kalt.) (Hemiptera: Aphididae) em condições de laboratório e campo

In this study, the aphid Lipaphis erysimi (Kalt) was reared at different temperatures, under laboratory and field conditions, aiming to obtain age-specific life tables. In the laboratory, L. erysimi was fed on kale, Brassica oleracea L. var acephala, and kept in incubators adjusted to 10, 15, 20, 25 and 30°C, 14h photophase and 70±10% RH. The longest mean generation time (T) was observed at 15°C (23.86 days) and the shortest at 30°C (7.18 days), while the smallest net reproductive rate (R0) occurred at 15°C (4.30) and largest one at 25°C (38.29). For the temperatures of 15, 20, 25 and 30°C, the intrinsic rate of natural increase (rm) and the finite rate of increase (λ) were 0.06/1.06, 0.24/1.27, 0.28/1.33 and 0.23/1.25, respectively. The doubling time (DT) at 15, 20, 25 and 30°C were 11.55, 2.80, 2.47, and 3.01 days, respectively. Under field conditions, the net reproductive rate (R0) of L. erysimi was larger in the winter (53.50) than in the summer (40.99), the same being observed for the mean generation time (T), which was 13.85 days in the winter and 7.57 days in the summer. The intrinsic rate of natural increase (rm) and the finite rate of increase (λ) were 0.29/1.34 and 0.40/1.63 for winter and summer, respectively. The doubling time (DT) observed for winter (2.39 days) was larger than the one observed for summer (1.41 days). The temperature affects longevity of L. erysimi and the best parameters of life table of fertility under laboratory conditions are obtained at 25°C. The data obtained in field conditions reinforced this finding. The daily fecundity was higher and longevity was smaller in the summer than in the winter, thus increasing the innate capacity of increasing in number and duplicating the population in a shorter period of time.

Papel das Yops secretadas por Yersinia sobre a resposta imune do hospedeiro

The genus Yersinia contains three species pathogenic to humans: Y. pestis, Y. enterocolitica e Y. pseudotuberculosis. The pathogenicity of Yersinia is linked to the presence of a 70-kb virulence plasmid (pYV) that is common to the three species and codifies a type III secretion system and a set of virulence proteins, including those known as Yersinia outer proteins (Yops), that are exported by this system when the bacteria encounter host cells. Two Yops translocators (YopB and YopD) are inserted into the host plasma membrane and transport six effectors (YopO, YopH, YopM, YopJ and YopT) across the membrane into the cytosol of the host cell. The Yops effectors interfere with multiple signaling pathways of the infected cell, affecting both the innate and adaptive immune responses. This article focuses on the role of Yops in the modulation of the host immune response.

Pro- and anti-inflammatory cytokines produced by human monocytes challenged in vitro with Paracoccidioides brasiliensis

Monocytes and macrophages play a central role in innate and adaptive immune response against systemic fungal infections. Imbalances in suppressor or stimulatory cytokine secretion caused by these cells may influence disease development, microorganism death, and the nature of the adaptive immune response. This study analyzed the monocyte cytokine profiles of healthy individuals challenged with high and low virulent strains of P. brasiliensis and mRNA cytokine expression kinetics by reverse transcription polymerase chain reaction (RT-PCR). Peripheral blood monocytes from healthy volunteers were cultured in vitro with and without virulent (Pb18) or low virulence (Pb265) strains from P. brasiliensis viable yeast cells. Interleukin-1 beta (IL-1β), IL-6, IL-8, IL-10, tumor necrosis factor-alpha (TNF-α), and transforming growth factor-beta (TGF-β1) were measured in culture supernatants by enzyme immunoassay (ELISA), and mRNA cytokine expression was determined by RT-PCR at 0, 4, 8, 12, 18 and 48 hr. Both P. brasiliensis strains induced monocyte production of IL-1β, IL-6, IL-10 and TNF-α. Pb18 induced higher levels of IL-1β, IL-6, and IL-10 than Pb265. IL-8 and TGF-β1 levels were not significantly different from those cultured without stimulus. The mRNA cytokine expression was similar to supernatant cytokines measured by ELISA. In vitro monocyte challenge with virulent P. brasiliensis strain induces earlier and higher levels of pro- and anti-inflammatory cytokines than low virulence strain.

Susceptibility/resistance of Anticarsia gemmatalis larvae to its nucleopolyhedrovirus (AgMNPV): Structural study of the peritrophic membrane

This investigation compares the peritrophic membrane (PM) morphology along the midgut of susceptible (SL) and resistant (RL) Anticarsia gemmatalis larvae to the AgMNPV. The PM increased the thickness from the anterior to the posterior midgut region in both insects strain; however, the intensity of FITC-WGA reaction of the PM in the RL were greater than in SL. The PM in RL was ultrastructurally constituted by several layers of fibrous/vesicular materials in comparison with the few ones in SL. Our results showed that the structure of PM in the RL could be one of the resistance barriers to AgMNPV. © 2007.

Interleukin-15: Its role in microbial infections

Interleukin-15 (IL-15) is a pleiotropic cytokine which regulates the proliferation, survival and the secretory activities of many distinct cell types in the body. This cytokine is produced by macrophages and many other cell types in response to infectious agents; it controls growth and differentiation of T and B lymphocytes, activation of Natural Killer (NK) and phagocytic cells, and contributes to the homeostasis of the immune system. The present review focuses on the biological and modulatory effects of IL-15 in microbial infections and shows that this cytokine may play a role in the host defense against infections by inducing activation of effector cells from both innate and adaptive immune system.

Seleção de genótipos resistentes de amendoinzeiro a Anticarsia gemmatalis Hübner (Lepidoptera: Noctuidae) com base em análises multivariadas

The velvetbean caterpillar Anticarsia gemmatalis Hübner attacks peanut leaves, and the use of resistant varieties has directly contributed to ecological and economic aspects of pest control. The aim of this work was to select resistant peanut genotypes to A. gemmatalis using cluster analyses (dendogram obtained by Ward's methods and K-means) and Principal Components analysis for data interpretation. The evaluated genotypes were: IAC 5, IAC 8112, IAC 22 and IAC Tatu ST with upright growth habit, and IAC 147, IAC 125, IAC Caiapó and IAC Runner 886 with runner growth habit, and soybean genotype BR 16 as a susceptible control. The biological parameters: leaf consumption, larval (4o instar) and pupal (24h old) weight, larval and pupal development time and adult longevity were evaluated at laboratory conditions. The genotypes IAC 147 and IAC Runner 886 were resistant to A. gemmatalis in both cluster tests, grouping apart from most of the other genotypes. Both dendrogram and K-means methods provided satisfactory biological explanation, and they can be complementary used together with Principal Component and vice-versa. These results suggest that cluster analyses may be an important statistical tool in the selection of host plant resistance.

Molecular basis for defining the pineal gland and pinealocytes as targets for tumor necrosis factor

The pineal gland, the gland that translates darkness into an endocrine signal by releasing melatonin at night, is now considered a key player in the mounting of an innate immune response. Tumor necrosis factor (TNF), the first pro-inflammatory cytokine to be released by an inflammatory response, suppresses the translation of the key enzyme of melatonin synthesis (arylalkylamine-N-acetyltransferase, Aanat). Here, we show that TNF receptors of the subtype 1 (TNF-R1) are expressed by astrocytes, microglia, and pinealocytes. We also show that the TNF signaling reduces the level of inhibitory nuclear factor kappa B protein subtype A (NFKBIA), leading to the nuclear translocation of two NFKB dimers, p50/p50, and p50/RelA. The lack of a transactivating domain in the p50/p50 dimer suggests that this dimer is responsible for the repression of Aanat transcription. Meanwhile, p50/RelA promotes the expression of inducible nitric oxide synthase (iNOS) and the production of nitric oxide, which inhibits adrenergically induced melatonin production. Together, these data provide a mechanistic basis for considering pinealocytes a target ofTNF and reinforce the idea that the suppression of pineal melatonin is one of the mechanisms involved in mounting an innate immune response. © 2011 Carvalho-Sousa, da Silveira Cruz-Machado, Tamura, Fernandes, Pinato, Muxel, Cecon and Markus.