Morphology and morphometry of Paratanaisia bragai () Freitas, 1959 (Digenea, Eucotylidae) through light and scanning electron microscopy.

Paratanaisia bragai is a digenetic trematode that reaches sexual maturity in the kidney collecting ducts of domestic and wild birds, while the snails Subulina octona and Leptinaria unilamellata serve as its intermediate hosts in Brazil. The present study analyzed the morphology and morphometry of P. bragai. Adult specimens of the parasite were collected from naturally infected Columba livia kidneys, fixed and prepared for observation via bright field and differential interference contrast light microscopy and scanning electron microscopy. The parasite has an elongated and flattened body, with a subterminal oral sucker located at the anterior end of the body, as observed by all techniques used. Staining the parasite with hematoxylin-eosin enabled observation of the pharynx, located posteriorly to the oral sucker, the vitelline glands, which are extra-cecal and extend anteriorly to the pre-ovarian region and later to the median region of the body, and intestinal caeca parallel to the vitelline glands. The presence and functionality of the acetabulum are controversial points in the literature, but it was observed in all specimens analyzed by scanning electron microscopy, with a major diameter of 38.36 ± 6.96 (28.77 - 45.39) and minor diameter of 31.59 ± 7.04 (21.75 - 38.16). Close to the acetabulum, scales were observed in the integument of the parasite. Scales with (1 - 5) blade divisions were identified. In the genital pore, it was possible to see the everted cirrus with rosette shape. The excretory pore (first morphometric record) is dorsal and subterminal, with major diameter of 12.27 ± 9.16 (5.79 - 18.75) and minor diameter of 3.95 ± 1.49 (2.89 - 5.00).

In vitro treatment of Toxoplasma gondii with copper(II) complexes induces apoptosis-like and cellular division alterations.

Toxoplasma gondii is the causative agent of toxoplasmosis, which is one of the most common parasitic diseases in the world. This pathogen causes severe damage to immunocompromised hosts, and the most frequently used therapy is the combination of pyrimethamine and sulfadiazine, which has side effects. Thus, there is a need for new therapies that target T. gondii. Herein, we present the anti-Toxoplasma effect of two new copper(II) complexes: [(H2L1) Cu (µ-Cl)2 Cu(H2L1)] Cl2·5H2O (1) and [(H2L2) Cu (µ-Cl)2 Cu(H2L2)] Cl2·6H2O (2). Complexes (1) and (2) irreversibly controlled parasite growth in vitro, with IC50 values of 0.78µM and 3.57µM, respectively, after 48h. These complexes induced part of the tachyzoite population to convert to bradyzoites, which eventually die. The cell death mechanism was unknown, but signs of apoptosis, such as membrane blebs and nuclear fragmentation, and necrosis, such as plasma membrane disruption, intense cytoplasm vesiculation and the release of cellular contents, were seen. In addition, complex (2) interfered with the correct disposition of the inner membrane complex of the parasite, affecting cell division. These results indicate that these copper complexes have potential effects against T. gondii and may be used as drugs in the future or serve as prototypes for the development of new drugs to treat toxoplasmosis.

Reduction of Toxoplasma gondii Development Due to Inhibition of Parasite Antioxidant Enzymes by a Dinuclear Iron(III) Compound.

Toxoplasma gondii, the causative agent of toxoplasmosis, is an obligate intracellular protozoan that can infect a wide range of vertebrate cells. Here, we describe the cytotoxic effects of the dinuclear iron compound [Fe(HPCINOL)(SO4)]2-µ-oxo, in which HPCINOL is the ligand 1-(bis-pyridin-2-ylmethyl-amino)-3-chloropropan-2-ol, on T. gondii infecting LLC-MK2 host cells. This compound was not toxic to LLC-MK2 cells at concentrations of up to 200 µM but was very active against the parasite, with a 50% inhibitory concentration (IC50) of 3.6 µM after 48 h of treatment. Cyst formation was observed after treatment, as indicated by the appearance of a cyst wall, Dolichos biflorus lectin staining, and scanning and transmission electron microscopy characteristics. Ultrastructural changes were also seen in T. gondii, including membrane blebs and clefts in the cytoplasm, with inclusions similar to amylopectin granules, which are typically found in bradyzoites. An analysis of the cell death pathways in the parasite revealed that the compound caused a combination of apoptosis and autophagy. Fluorescence assays demonstrated that the redox environment in the LLC-MK2 cells becomes oxidant in the presence of the iron compound. Furthermore, a reduction in superoxide dismutase and catalase activities in the treated parasites and the presence of reactive oxygen species within the parasitophorous vacuoles were observed, indicating an impaired protozoan response against these radicals. These findings suggest that this compound disturbs the redox equilibrium of T. gondii, inducing cystogenesis and parasite death.

Leukocyte ultrastructure, hematological and serum biochemical profiles of ostriches (Struthio camelus).

In the last decade ostrich farms spread throughout the world as an alternative source of investment. Although previous studies have reported hematology and biochemical values for ostriches from several regions of the world, little information is available regarding leukocyte morphology. This study reports the morphology and ultrastructure of ostrich leukocytes and hematology and biochemical values from birds raised in Brazil. Heterophils presented a lobulated nucleus, and fusiform, and acidophilic and peroxidase-negative granules. Ultrastructurally, 2 kinds of cytoplasmic granules were observed: one was large and fusiform and the other smaller with heterogeneous morphology and electrondensity; granules were peroxidase-negative. Eosinophils had a kidney-shaped eccentrically placed nucleus that was rarely lobulated and eosinophilic, round, and peroxidase-positive granules. At the ultrastructure level, 2 main kinds of granules with the same size and form but different electron density were seen; granules were peroxidase-positive. Lymphocytes and thrombocytes had the same characteristics of other avian species; monocytes presented morphological heterogeneity. Hematological and serum biochemical profiles had no sex influence and were established for ostriches raised in southeastern Brazil. These parameters will help the diagnosis of specific ostrich pathologies and serve as basic knowledge for studies in immunology and comparative avian pathology.

Acid phosphatase activity during the interaction of the nematophagous fungus Duddingtonia flagrans with the nematode Panagrellus sp.

The use of Duddingtonia flagrans, a nematode-trapping fungus, has been investigated as a biological control method against free living larvae of gastrointestinal nematodes of livestock animals. This fungus captures and infects the nematode by cuticle penetration, immobilization and digestion of the internal contents. It has been suggested that this sequence of events occurs by a combination of physical and enzymatical activities. This report characterizes the acid phosphatase activity during the interaction of D. flagrans with the free-living nematode Panagrellus sp. The optimum pH for the hydrolysis of the acid phosphatase substrate p-nitrophenyl phosphate was 2.2, 2.8 and 5.4 from D. flagrans alone and 2.2 and 5.4 for Panagrellus sp alone, fungus-nematode interaction in liquid medium and fungus-nematode interaction in solid medium. Different acid phosphatase activity bands were detected by SDS-PAGE. Maximum acid phosphatase activity of the fungus or nematode alone and of the fungus-nematode interaction occurred within 70min of incubation in the presence of the substrate 4-methylumbelliferyl phosphate. The activity of this enzyme was significantly higher for the fungus-nematode interaction when compared to the organisms alone, indicating a synergistic response. Furthermore, structures appeared in the hyphae after 30min, nematodes were observed adhered after 40min and many were captured by the typical fungus traps after 70min of interaction. The participation of acid phosphatase activity and its importance during the interaction of the fungus with the nematode were discussed.

Effects of entomopathogenic bacterium Photorhabdus temperata infection on the digestive enzymes of Diatraea saccharalis (Lepidoptera: Crambidae) larvae.

This study investigated the effects of Photorhabdus temperata infection on the activities of digestive enzymes of the sugarcane stalk borer Diatraea saccharalis. Non-infected D. saccharalis larvae present a major alpha-amylase, several proteinases, three sucrose hydrolases and two alpha-glucosidases in their midgut. Analysis of these hydrolases by electrophoresis and "in gel" assays showed that the activities of all enzymes decreased following infection, with an initial decline observed 12 h after infection. The activities of alpha-glucosidases decreased by 50% twelve hours after infection, whereas, at this time, the alpha-galactosidase activities decreased by 70%. Interestingly, the animals died 48 h after infection, but approximately 5% of all the enzymes tested remained active in the midgut following host death. At this time, most of the cultivable native intestinal bacteria had died.

Mapping IgE-binding epitopes of Ric c 1 and Ric c 3, allergens from Ricinus communis, by mast cell degranulation assay.

Ric c 1 and Ric c 3 are the major castor bean allergens. In order to identify continuous IgE-epitopes in Ric c 1 and Ric c 3, pools of sera from rats immunized with a pool of 2S albumin from these seeds, Ric c 1 and Ric c 3 overlapping synthetic peptides, were used to screen for IgE-binding epitopes. The allergenic properties were monitored by mast cell degranulation assays, histamine quantification and human-IgE binding. Large and small chains isolated from these proteins present allergenic properties. Four continuous epitopes were identified in Ric c 3 and two in Ric c 1. This knowledge may allow the induction of protective antibody responses to antagonize the IgE recognition.

Cytoskeleton, endoplasmic reticulum and nucleus alterations in CHO-K1 cell line after Crotalus durissus terrificus (South American rattlesnake) venom treatment

Snake venoms are toxic to a variety of cell types. However, the intracellular damages and the cell death fate induced by venom are unclear. In the present work, the action of the South American rattlesnake Crotalus durissus terrificus venom on CHO-K1 cell line was analyzed. The cells CHO-K1 were incubated with C. d. terrificus venom (10, 50 and 100g/ml) for 1 and 24 hours, and structural alterations of actin filaments, endoplasmic reticulum and nucleus were assessed using specific fluorescent probes and agarose gel electrophoresis for DNA fragmentation. Significant structural changes were observed in all analyzed structures. DNA fragmentation was detected suggesting that, at the concentrations used, the venom induced apoptosis.

Nitric oxide inhibition after Toxoplasma gondii infection of chicken macrophage cell lines.

Toxoplasma gondii infects many warm-blooded animals, including chickens. However, little is known about how this protozoan behaves within chicken macrophages. Thus, the microbicidal biology of HD11 and MQ-NCSU (available chicken macrophage cell lines) and the escaping mechanism of T. gondii were investigated. After infection, both cell lines were activated with lipopolysaccharide (LPS) and nitric oxide (NO), and reactive oxygen intermediates (ROI) were evaluated. T. gondii infected both cell lines, and 30 and 60% inhibition of NO production was detected in MQ-NCSU and HD11, respectively. In HD11, NO inhibition was not dependent on cyclooxygenase products. Although NO was partially inhibited, it did control T. gondii multiplication, showing the importance of this microbicidal molecule. Production of ROI was not detected in either cell line after T. gondii or yeast interaction. NADPH diaphorase (NADPH-d) activity, a histochemical marker of inducible NO synthase (iNOS), was detected at various levels in the HD11 population activated with LPS. The HD11 population infected with T. gondii showed a decrease in NADPH-d, indicating that NO production inhibition was related to iNOS disappearance in infected macrophages. These results demonstrate that in chicken macrophages T. gondii can also inhibit NO production, which suggests that an iNOS suppression mechanism might be used for better survival in macrophages.

Ultrastructural effects of two phthalocyanines in CHO-K1 and HeLa cells after laser irradiation

The effects of Photodynamic Therapy using 2nd generation photosensitizers have been widely investigated aiming clinical application treatment of solid neoplasms. In this work, ultrastructure changes caused by the action of two 2nd generation photosensitizers and laser irradiation on CHO-K1 and HeLa (neoplastic) cells were analyzed by transmission electron microscopy. Aluminum phthalocyanine chloride, aluminum phthalocyanine tetrasulfonate chloride and radiation from a semiconductor laser at a fluency of 0.5 J/cm2 (Power=26 mW; lambda=.670 nm) were used. The results showed induction of apoptosis. Such alterations where observed in HeLa but not in CHO-K1 cells after Aluminum phthalocyanine tetrasulfonate chloride (AlPcS4, photodynamic treatment. The Aluminum phthalocyanine chloride (AlPc) photodynamic treatment induced necrosis on the neoplastic cell line, and cytoplasm and nuclear alterations on the normal cell line. (AU)

Ultrastructural effects of two phthalocyanines in CHO-K1 and HeLa cells after laser irradiation

The effects of Photodynamic Therapy using 2nd generation photosensitizers have been widely investigated aiming clinical application treatment of solid neoplasms. In this work, ultrastructure changes caused by the action of two 2nd generation photosensitizers and laser irradiation on CHO-K1 and HeLa (neoplastic) cells were analyzed by transmission electron microscopy. Aluminum phthalocyanine chloride, aluminum phthalocyanine tetrasulfonate chloride and radiation from a semiconductor laser at a fluency of 0.5 J/cm2 (Power=26 mW; lambda=.670 nm) were used. The results showed induction of apoptosis. Such alterations where observed in HeLa but not in CHO-K1 cells after Aluminum phthalocyanine tetrasulfonate chloride (AlPcS4, photodynamic treatment. The Aluminum phthalocyanine chloride (AlPc) photodynamic treatment induced necrosis on the neoplastic cell line, and cytoplasm and nuclear alterations on the normal cell line.

Cowpea (Vigna unguiculata) vicilins bind to the peritrophic membrane of larval sugarcane stalk borer (Diatraea saccharalis).

In this work, we show that vicilins from two Vigna unguiculata (cowpea) genotypes, Epace-10 and IT 81D-1045, which are susceptible and resistant to attack by the cowpea weevil Callosobruchus maculatus, respectively, associate with the peritrophic membrane (PM) from larvae of Diatraea saccharalis. Solutions with increasing concentrations of vicilins were incubated with PM of the larvae and subsequently analysed by electrophoresis with SDS. It was observed that the majority of the bands of approximately 50,000 Da (characteristic of vicilins) did not appear in the separating gel and only lower molecular weight polypeptides were seen. When vicilins were incubated with PM, and the solution was then heated after the incubation, the band pattern in the gel appeared completely different. It was observed that the vicilins were being hydrolysed by proteinases associated with the PM. When the incubated samples were heated after the reaction, the major bands reappeared, demonstrating that most of the vicilin molecules had bound to the PM of D. saccharalis. These results suggest that when the vicilins are in contact with the PM they are bound and also digested by the PM of this insect. The major and several minor proteinases from the PM were extracted with Triton X-100 and their activity and the inhibition of this activity were analysed by ingel assays. Based on the effects of proteinase inhibitors, the PM-associated activity is due to serine class proteinases. Larvae of D. saccharalis were fed on artificial diets containing purified vicilins from Epace-10 or IT 81D-1045 seeds. Vicilins from Epace-10 did not affect the larval development, while IT 81D-1045 vicilins reduced significantly the survival rate of the sugar cane borer.

Digestion of legume starch granules by larvae of Zabrotes subfasciatus (Coleoptera: bruchidae) and the induction of alpha-amylases in response to different diets.

Zabrotes subfasciatus larvae possess three alpha-amylase isoforms as determined by in gel assays following SDS-PAGE. The two minor isoforms present lower electrophoretic mobility than the major form, and seem to occur as a heterodimer. When developed inside Vigna unguiculata (cowpea) seeds, fourth instar larvae have minor quantities of the slow-migrating forms, but when reared on seeds of Phaseolus vulgaris (common bean) or Phaseolus lunatus, the two slow-migrating forms are expressed in higher amounts, while activity of the major form was independent of the host seed. Larvae developing inside cowpea seeds at the beginning of the fourth instar were fed on flour from cotyledons of cowpea or common bean. Larvae fed on the common bean flour started to express the dimer in higher amounts when compared with the control larvae fed on cowpea flour. In an attempt to correlate differences between starch granules and the induction of alpha-amylases, a detailed study on the digestive process of the granules was conducted. Incorporation of purified starch granules into artificial diets did not induce the two minor alpha-amylases. The in vitro hydrolysis rates of purified granules and the pattern of dextrins liberated by the different alpha-amylases were similar for the two legume species. The starch granules enter the midgut extensively damaged, which may facilitate the access to the more susceptible parts of the granules to enzymatic attack.

Nitric oxide is not involved in the killing of Trypanosoma cruzi by chicken macrophages.

It is known that chicken macrophages derived in vitro from blood monocytes have the capacity to destroy Trypanosoma cruzi, but Toxoplasma gondii can survive within these cells. This study was performed to determine the involvement of nitric oxide (NO) in the killing of T. cruzi by chicken macrophages. Activated (by interferon-gamma and lipopolysaccharide) mouse peritoneal macrophages were used as controls. Macrophages were infected with T. cruzi and T. gondii; after 2, 24, and 48 h, NO was assayed using the Griess reagent. Respiratory-burst involvement, revealed by the reduction of nitroblue tetrazolium (NBT), was determined in chicken macrophages. Chicken macrophages did not produce NO; mouse macrophages were capable of producing NO with no multiplication of parasites. Reduction of NBT could be detected in chicken macrophages that interacted with T. cruzi but was absent in those that interacted with T. gondii. These results demonstrate that chicken macrophages do not use NO as a microbicidal agent when infected with T. cruzi or T. gondii.

Chicken thrombocytes in culture: lymphocyte-conditioned medium delays apoptosis.

Chicken thrombocytes are nucleated cells, analogs to mammalian platelets. These cells are involved in hemostasis, phagocytosis and secretion of specific products. Most of the properties of avian thrombocytes have been established in experiments that employed recently isolated blood cells. Attempts to cultivate these cells for a long period of time under optimal culture conditions for peripheral blood cells were unsuccessful; thrombocytes died after 24 h of cultivation unlike macrophages cocultured with them. Here we investigate the reasons and type of thrombocyte death in culture. Thrombocytes were separated from peripheral blood of roosters and cultured for 48 h. The influence of different culture conditions on thrombocyte viability was studied. Cells were cultured as adherent cell monolayers or under agitation (preventing adherence), in the presence or lack of lymphocytes or their soluble factors, and various concentrations of fetal bovine serum. After 24 h in standard culture thrombocytes displayed cytoplasm and chromatin condensation, DNA cleaved into oligonucleosomal fragments and unaltered mitochondria. These results strongly suggest that thrombocytes suffer an apoptotic cell death in culture. Apoptosis could be delayed by culturing thrombocytes in the presence of lymphocytes or their soluble factors.

Alpha-2-macroglobulin receptor is differently expressed in peritoneal macrophages from C3H and C57/B16 mice and up-regulated during Trypanosoma cruzi infection.

Chagas' disease is caused by the protozoan Trypanosoma cruzi. The acute phase of T. cruzi infection, which can be conveniently studied in mouse models, is thought to be a determinant of survival and of the pathological features of the chronic phase. With regard to the occurrence of early death and parasitaemia levels C3H and C57/B16 mice are classically classified as 'susceptible' and 'resistant' to T. cruzi infection, respectively. Alpha-2-macroglobulin (A2M) is a physiological proteinase inhibitor found in tissues and in the plasma of mammals. Previous studies showed that A2M plasma levels increase in C3H mice acutely infected by T. cruzi but do not change in C57/B16 mice. This difference might involve two possible phenomena, concerning A2M synthesis and/or clearance by its receptor (A2M-R). In this study, we examined by flow cytometry the binding of A2M-trypsin conjugated with FITC to macrophages from normal and T. cruzi-infected C3H and C57/B16 mice. Our present results show for the first time that A2M-R is expressed more (by approximately 33%) in the surface of cells from normal C57/B16 as compared to C3H mice. We also show that A2M-R expression is up-regulated in both strains during acute T. cruzi infection, but at higher levels and earlier in C57/B16 mice. At the same time, peritoneal cells become activated as judged by: (1) increase of their size and granularity; (2) gradual increase of Fc gamma RII/III expression assayed by 2.4G2 binding; (3) down-modulation of F4/80 binding, a mAb that recognizes an antigen typically expressed in resident macrophages. Finally, our results indicate that as macrophages become activated in vivo a higher expression of A2M-R is observed.

Further studies on the phagocytic capacity of chicken thrombocytes.

Thrombocytes, functional analog to mammalian platelets, have been described as the primary circulating phagocyte in chicken blood when challenged with bacteria (Chang and Hamilton, 1979). In order to determine if the phagocytic capacity could be extended to protozoa, interaction of chicken thrombocytes with tachyzoites of Toxoplasma gondii and bloodstream trypomastigotes of Trypanosoma cruzi was performed. Interaction with Staphylococcus aureus and Escherichia coli was also performed using fluoresceinated and living bacteria, to be examined by fluorescence microscopy (after ethidium bromide staining) and transmission electron microscopy (after ruthenium red fixation). Using these approaches it was possible to distinguish internalized from attached bacteria. T. cruzi was only found attached to the thrombocyte surface while T. gondii could be observed within the cell. To determine if T. gondii invasion was active or by phagocytosis, interaction was performed under conditions where active penetration and phagocytosis were inhibited by previous fixation of the parasites or treatment of thrombocytes with cytochalasin D, respectively. Interactions with fixed T. gondii showed only attached parasites. Cytochalasin D treated thrombocytes could still be found with internalized T. gondii. By fluorescence and transmission electron microscopy it was possible to observe a small number of bacteria internalized by thrombocytes. These findings show that T. gondii invade thrombocytes through an active penetration process and these blood cells cannot be considered as the primary circulating phagocyte in chicken.

Coculture of chicken thrombocytes and monocytes: morphological changes and lectin binding

Chicken leukocytes were separated from blood on a Percoll cushion following adherence on coverslips, resulting in a coculture of thrombocytes and monocytes. This system was characterized by light microscopy, scanning and transmission electron microscopy, by lectin binding and actin localization in thrombocytes. During the first 24 hours nuclear condensation, cytoplasmic shrinkage, detachment and death of thrombocytes were observed. In contrast, monocytes gradually increased their spreading capacity, specially after thrombocyte detachment from the coverslips. During culture, a large number of fucose and beta-galactose residues were expressed on the surface of thrombocytes, revealed by the lectins Ulex europaeus I and Arachis hypogaea, respectively. Labeling of the monocyte surface with several lectins also increased with the cultivation time. Thrombocytes showed the formation of a net with actin involvement

Coculture of chicken thrombocytes and monocytes: morphological changes and lectin binding

Chicken leukocytes were separated from blood on a Percoll cushion following adherence on coverslips, resulting in a coculture of thrombocytes and monocytes. This system was characterized by light microscopy, scanning and transmission electron microscopy, by lectin binding and actin localization in thrombocytes. During the first 24 hours nuclear condensation, cytoplasmic shrinkage, detachment and death of thrombocytes were observed. In contrast, monocytes gradually increased their spreading capacity, specially after thrombocyte detachment from the coverslips. During culture, a large number of fucose and beta-galactose residues were expressed on the surface of thrombocytes, revealed by the lectins Ulex europaeus I and Arachis hypogaea, respectively. Labeling of the monocyte surface with several lectins also increased with the cultivation time. Thrombocytes showed the formation of a net with actin involvement

Coculture of chicken thrombocytes and monocytes: morphological changes and lectin binding.

Chicken leukocytes were separated from blood on a Percoll cushion following adherence on coverslips, resulting in a coculture of thrombocytes and monocytes. This system was characterized by light microscopy, scanning and transmission electron microscopy, by lectin binding and actin localization in thrombocytes. During the first 24 hours nuclear condensation, cytoplasmic shrinkage, detachment and death of thrombocytes were observed. In contrast, monocytes gradually increased their spreading capacity, specially after thrombocyte detachment from the coverslips. During culture, a large number of fucose and beta-galactose residues were expressed on the surface of thrombocytes, revealed by the lectins Ulex europaeus I and Arachis hypogaea, respectively. Labeling of the monocyte surface with several lectins also increased with the cultivation time. Thrombocytes showed the formation of a net with actin involvement.