Diminazene Aceturate (Berenil) Modulates the Host Cellular and Inflammatory Responses to Trypanosoma congolense Infection

Background

Trypanosoma congolense are extracellular and intravascular blood parasites that cause debilitating acute or chronic disease in cattle and other domestic animals. Diminazene aceturate (Berenil) has been widely used as a chemotherapeutic agent for trypanosomiasis in livestock since 1955. As in livestock, treatment of infected highly susceptible BALB/c mice with Berenil leads to rapid control of parasitemia and survival from an otherwise lethal infection. The molecular and biochemical mechanisms of action of Berenil are still not very well defined and its effect on the host immune system has remained relatively unstudied. Here, we investigated whether Berenil has, in addition to its trypanolytic effect, a modulatory effect on the host immune response to Trypanosoma congolense.

Methodology/Principal Findings

BALB/c and C57BL/6 mice were infected intraperitoneally with T. congolense, treated with Berenil and the expression of CD25 and FoxP3 on splenic cells was assessed directly ex vivo. In addition, serum levels and spontaneous and LPS-induced production of pro-inflammatory cytokines by splenic and hepatic CD11b⁺ cells were determined by ELISA. Berenil treatment significantly reduced the percentages of CD25⁺ cells, a concomitant reduction in the percentage of regulatory (CD4⁺Foxp3⁺) T cells and a striking reduction in serum levels of disease exacerbating pro-inflammatory cytokines including IL-6, IL-12, TNF and IFN-γ. Furthermore, Berenil treatment significantly suppressed spontaneous and LPS-induced production of inflammatory cytokines by splenic and liver macrophages and significantly ameliorated LPS-induced septic shock and the associated cytokine storm.

Conclusions/Significance

Collectively, these results provide evidence that in addition to its direct trypanolytic effect, Berenil also modulates the host immune response to the parasite in a manner that dampen excessive immune activation and production of pathology-promoting pro-inflammatory cytokines, suggesting that this drug may also be beneficial for treatment of disease conditions caused by excessive production of inflammatory cytokines.     

Molecular basis of antibody mediated immunity against Ehrlichia chaffeensis involves species-specific linear epitopes in tandem repeat proteins

Humoral immune mechanisms are an important component of protective immunity to Ehrlichia species. However, the molecular basis of antibody mediated immunity is not completely defined, and the role of most molecularly characterized major immunoreactive proteins is unknown. In previous studies, we mapped major species-specific continuous epitopes in three surface exposed and secreted tandem repeat proteins (TRP32, TRP47 and TRP120). In this study, we report that protection is provided by antibodies against these molecularly defined TRP epitopes using in vitro and in vivo models. Protection was demonstrated in vitro after prophylactic and therapeutic administration of epitope-specific anti-TRP antibodies, suggesting that the protective mechanisms involve extracellular and intracellular antibody-mediated effects. In vivo passive transfer of individual epitope-specific TRP sera significantly reduced the ehrlichial load and splenomegaly, and protected mice against lethal infection. Moreover, the combination of antibodies to all three TRPs provided enhanced reduction in ehrlichial load similar to that of Ehrlichia chaffeensis immune sera. IgG1 was the predominant antibody isotype in the epitope-specific TRP mouse sera. These results demonstrate that antibodies against linear epitopes in TRP32, TRP47 and TRP120 are protective during E. chaffeensis infection and involves extracellular and intracellular antibody-mediated mechanisms.     

Cadmium stress affects seed germination and seedling growth in <Emphasis Type="Italic">Sorghum bicolor</Emphasis> (L.) Moench by changing the activities of hydrolyzing enzymes

Seed germination, one of the most important phases in the life cycle of a plant, is highly responsive to existing environment. Hydrolyzing enzymes play a major role in the mobilization of food reserves by hydrolyzing carbohydrates, proteins and fats. This paper reports on the effect of Cd toxicity on seed germination and the activities of hydrolyzing enzymes, like acid phosphatases (ACPs), proteases and α-amylases in Sorghum bicolor (L.) Moench. The metal uptake by embryonic axes and seeds was quantified. We found that sorghum could tolerate up to 0.5 mM Cd. At concentrations above 3.0 mM, seed germination was adversely affected with a complete cessation of seedling growth. All investigated hydrolyzing enzymes exhibited a significant decrease in activity with increasing Cd concentrations. The isozyme profiles indicated the loss of one or two isozymes of ACP, induction of a new isozyme for total protease (at 3.0 mM Cd) and a decline in the intensity of α-amylase isozymes. SEM studies revealed that Cd affected a change in root hair density. SEM investigations also confirmed the assay results of the inhibition of starch mobilization from endosperm. This suggested an inhibition of the hydrolysis of reserve carbohydrates and translocation of hydrolyzed sugars, ultimately resulting in decreased germination and disruption of seedling growth. Because sorghum is an important dryland crop, its response to the presence of Cd in agro-ecosystems and Cd-induced phytotoxicity during seed germination and seedling growth needs critical investigation.     

Cochocelis distribution on the firth of clyde: estimates of the lower limits of the photic zone

A series of transects in the Firth of Clyde have shown that filaments of Conchocelis in shell substrata are always the deepest growing red algae. The abundance of calcareous material on the sea bed and its invariable association with the perennial Conchocellis filaments offers a reliable means of estimating photic limits. Some interactions of grazing molluscs with the shell-boring organism have been observed. Some of the pitfalls to be encountered in field determinationsof Conchocelis and its consequent use as an indicator organism are described.     

Survival and growth of alpha-spores of Porphyra schizophylla Hollenberg (Rhodophyta: Bangiophyceae)

Alpha-spores of the intertidal Porphyra schizophylla Hollenberg f. norrisii Mumford appear able to tolerate environmental stress factors associated with intertidal habitats, (viz., drying of water films with salt crystal formation, increased salt concentrations in the surrounding water, exposure to humid air when spores are enclosed in water films), and to produce Conchocelis filaments of normal appearance when subsequently germinated in sea water cultures. Tolerances of lowered salinities were observed down to 17.4%., but little survival at salinities lower than this. Alpha-spore germination on thalli of intertidal macro-algae was observed, with initial penetration in some cases. Penetrations of algal thalli were observed with Conchocelis filaments of α-spores germinated on red algae from low intertidal and subtidal habitats. Cell recognition phenomena would seem to be involved in these growth responses.     

Phytochelatin synthesis and response of antioxidants during cadmium stress in Bacopa monnieri L.

The phytotoxicity imposed by cadmium (Cd) and its detoxifying responses of Bacopa monnieri L. have been investigated. Effect on biomass, photosynthetic pigments and protein level were evaluated as gross effect, while lipid peroxidation and electrolyte leakage reflected oxidative stress. Induction of phytochelatins and enzymatic and non-enzymatic antioxidants were monitored as plants primary and secondary metal detoxifying responses, respectively. Plants accumulated substantial amount of Cd in different plant parts (root, stem and leaf), the maximum being in roots (9240.11 microg g(-1) dw after 7 d at 100 microM). Cadmium induced oxidative stress, which was indicated by increase in lipid peroxidation and electrical conductivity with increase in metal concentration and exposure duration. Photosynthetic pigments showed progressive decline while protein showed slight increase at lower concentrations. Enzymes viz., superoxide dismutase (SOD, EC 1.15.1.1), guaiacol peroxidase (GPX, EC 1.11.1.7) ascorbate peroxidase (APX, EC 1.11.1.11) and glutathione reductase (GR, EC 1.6.4.2) showed stimulation except catalase (CAT, EC 1.11.1.6) which showed declining trend. Initially, an enhanced level of cysteine, glutathione and non-protein thiols was observed, which depleted with increase in exposure concentration and duration. Phytochelatins induced significantly at 10 microM Cd in roots and at 50 microM Cd in leaves. The phytochelatins decreased in roots at 50 microM Cd, which may be correlated with reduced level of GSH, probably due to reduced GR activity, which exerted increased oxidative stress as also evident by the phenotypic changes in the plant like browning of roots and slight yellowing of leaves. Thus, besides synthesis of phytochelatins, availability of GSH and concerted activity of GR seem to play a central role for Bacopa plants to combat oxidative stress caused by metal and to detoxify it. Plants ability to accumulate and tolerate high amount of Cd through enhanced level of PCs and various antioxidants suggest it to be a suitable candidate for phytoremediation.     

Conditioning domestic chickens to a magnetic anomaly

Young domestic chicks of two strains, ISA brown layers and White Leghorn X Australorps, were trained to associate a magnetic anomaly with food. This was done by feeding them in their housing boxes from a dish placed above a small coil that produced a magnetic anomaly roughly six times as strong as the local geomagnetic field. Unrewarded tests began on day 9 after hatching. In a square arena, two corresponding coils were placed underneath two opposite corners. One coil, the control coil, was double-wrapped producing no net magnetic field, while the other in the opposite corner produced a local magnetic anomaly similar to that experienced during feeding. The chicks favoured the corner with the anomaly from day 10 after hatching onward. Both strains of chickens showed this preference, indicating that they could sense the local changes in the magnetic field.     

Domestication of cardamom (Elettaria cardamomum) in Western Ghats, India: divergence in productive traits and a shift in major pollinators

Background and Aims

Elettaria cardamomum, a highly priced spice, is native to the Western Ghats of South India. Wild populations still occur in isolated patches in their natural habitats; however, much of today''s commercial product comes from cultivated sources. There is no information on domestication-related traits of this species; the main objective of this study was to compare wild and cultivated populations of cardamom in terms of vegetative and reproductive features in order to identify domestication syndromes and to examine whether the two populations have developed reproductive barriers.

Methods

Two wild populations and five cultivated plantations were used for the present study. Vegetative and floral traits, flowering phenology, pollination biology and breeding systems of wild and cultivated populations were compared. Effective pollinators amongst floral visitors were identified by confirming pollen transfer as well as by fruit set following their visit to virgin flowers. Manual pollinations were carried out in order to study the breeding systems of the two populations and reproductive barriers, if any, between them.

Key Results

Several productive traits including the number of branches, number of inflorescences, and total number of flowers per clump, number of flowers that open each day, the duration of flowering, the length of the flower and the amount of nectar per flower are significantly greater in cultivated cardamom. The principal pollinators in wild cardamom are solitary bees, Megachile sp. and two species of Amegilla, whereas those in cultivated cardamom are the social bees Apis dorsata, A. cerana and Trigona iridipennis. Both the wild and cultivated populations are self-compatible and there are no reproductive barriers between the two populations.

Conclusions

Domestication in cardamom has brought about significant changes in vegetative and reproductive traits and a shift in effective pollinators from native solitary bees to social bees. The shift in pollinators seems to be due to the availability of a large number of flowers for prolonged periods in cultivated cardamom that can attract and sustain social bees, rather than due to co-evolution of the flower and the pollinator.Key words: Elettaria cardamomum, wild cardamom, domestication, Amegilla sp., Apis cerana, Apis dorsata, Megachile sp., pollination efficiency, solitary bees, social bees