The Potential of <Emphasis Type="Italic">Lactobacillus casei</Emphasis> and <Emphasis Type="Italic">Entercoccus faecium</Emphasis> Combination as a Preventive Probiotic Against <Emphasis Type="Italic">Entamoeba</Emphasis>

Travellers’ diarrhoea caused by enteric protozoa like Entamoeba histolytica is among the most common protozoan diseases in developing countries. In developing countries, amoebiasis is the second most prevalent protozoan disease. This protozoan parasite is often known to coexist as a part of the normal gut microbiota. It is estimated that around 50–60 % of population in developing countries might be harbouring Entamoeba in an asymptomatic manner. Due to physiological perturbation or upon immuno-compromise, it can become virulent and then cause diarrhoea, bloody stools and may invade other organs if left untreated. Nitroimidazole drugs, namely metronidazole and tinidazole, are widely used to treat protozoan infections. These drugs often show dose-dependent side effects. With emerging antibiotic resistance, novel therapeutics to prevent parasitic infections is required. This study aims to study effect of probiotics on prevention of Amoebiasis. In this study, we have investigated the effect of selected probiotics on the growth of Entamoeba. From the list of probiotics being currently used, five bacterial strains were selected for testing. These probiotic strains were co-cultured with Entamoeba, and their effect on Entamoeba proliferation was checked. Of the five probiotics chosen, individual treatments of Lactobacillus casei and Enterococcus faecium showed a significant reduction of up to 71 % in parasite survival only at higher CFUs. When the two probiotics were used in combination, the percentage of survival reduced gradually further to 80 % at a total CFU of 10⁹ cells/ml of bacteria. The study lays the foundation for providing cost-effective prophylactic treatment for amoebiasis without the overuse of antibiotics.     

Overwintering survival and spring emergence inMeligethes aeneus: Effects of body weight, crowding, and soil treatment withBeauveria bassiana

High overwintering mortality was recorded forMeligethes aeneus in the field in Finland, ranging from 85 to 98% depending on the source of the overwintering population. The main factor explaining, variation in survival was the body weight of the beetles in the autumn: only the heaviest beetles survived. Body weight, on the other hand, was influenced by treatment of the rape field soil withBeauveria bassiana, resulting in a 50% decrease in winter survival compared with the reference. The soil treatment did not appear to have direct mortality effects (pathogenesis) on the beetle neither in the summer nor in the winter, and there was no apparent effect on survival of crowding of the insects at the overwintering site. Density dependence in overwintering survival ofM. aeneus may function through the availability of pollen food in the autumn, and intraspecific competition for it. Treatment of the rape field soil withB. bassiana may be a feasible way to increase, the winter mortality and to lower the pollen beetle populations, but requires further research.     

Baseline serum cholestanol as predictor of recurrent coronary events in subgroup of Scandinavian simvastatin survival study

Objectives: To investigate whether baseline serum cholestanol:cholesterol ratio, which is negatively related to cholesterol synthesis, could predict reduction of coronary events in the Scandinavian simvastatin survival study. Design: Follow up of patients with coronary heart disease in whom baseline ratios were related to major coronary events. Setting: Four universities in Finland. Subjects: A subgroup of 868 patients with coronary heart disease selected from the Scandinavian simvastatin survival study. Intervention: Treatment with simvastatin or placebo. Main outcome measures: Serum concentrations of low density lipoprotein and high density lipoprotein cholesterol, total triglyceride concentration, and cholesterol:cholestanol ratio. Major coronary events. Results: With increasing baseline quarter of cholestanol distribution the reduction in relative risk increased gradually from 0.623 (95% confidence interval 0.395 to 0.982) to 1.166 (0.791 to 1.72). The risk of recurrence of major coronary events increased 2.2-fold (P<0.01) by multiple logistic regression analysis between the lowest and highest quarter of cholestanol. The ratio of cholestanol was related inversely to the body mass index and directly to high density lipoprotein cholesterol and triglyceride concentrations but their quarters of distribution were not related to risk reduction.Conclusions: Measurement of serum cholestanol concentration revealed a subgroup of patients with coronary heart disease in whom coronary events were not reduced by simvastatin treatment. Thus, patients with high baseline synthesis of cholesterol seem to be responders whereas those with low synthesis of cholesterol are non-responders.

Key messages

• Recurrence of major coronary events is reduced by statin treatment in about one third of patients with coronary heart disease, to predict those who will not respond has not been possible from baseline lipid concentrations in the Scandinavian simvastatin survival.
• This study showed that increasing quarters of cholestanol:cholesterol ratio, reflecting decreasing synthesis of cholesterol, were related to recurrence of major coronary events during simvastatin treatment in a Finnish subgroup (n=868) of the Scandinavian study.
• The subjects with lowest baseline quarters of cholestanol were associated with significantly reduced relative risk of major coronary events, while the risk in the highest quarter was unchanged and 2.2 times higher than in the lowest one.
• Cholestanol:cholesterol ratios were related inversely to the body mass index and directly to high density lipoprotein cholesterol and triglyceride concentrations, but their quarters were unrelated to risk reduction.
• The findings suggest that patients with coronary disease who have high absorption (high basal cholestanol:cholesterol) and low synthesis of cholesterol do not benefit from statin treatment alone and that they can be identified by measuring serum cholestanol concentration before treatment.

     

Effects of wood bark ash on the growth and nutrition of a Scots pine afforestation in central Finland

Results are presented from a fertilization experiment with wood bark ash (0, 1, 2, 5, 10, 20 Mg ha^-1) applied to prevent and cure visible nutrient disorders of young Scots pine established on a peatland field. 13 years after fertilization, dieback of trees and other symptoms of nutrient disorders were substantially reduced or even eliminated, especially where higher doses had been applied. The volume of the growing stock was more than 70 m³ ha^-1 for the highest dose while control plots produced less than 15 m³ ha^-1. Vegetation characteristics changed following ash treatments with high ash doses favouring grasses and low ash doses promoting mosses. Some major changes in soil and foliar nutrient concentrations were evident due to ash fertilization. K and B, however, were clearly the most limiting nutrients that could be cycled where high doses of ash were used. This was particularly the case with a dose of 20 Mg ha^-1. Decomposition of the topsoil was at its highest on plots with ash doses of 5 and 10 Mg ha^-1 ash and at its lowest when the dose was 2 Mg ha^-1. This was partly due to differences in the C/N ratio of the soil. All decomposition parameters indicated a high degree of humification in the topsoil. High N content (of organic material), low C/N in the soil and optimum levels of foliar N concentrations suggested sufficient N mineralization for tree growth to have occurred in the soil.     

Characterization of Precursor PfHsp60 in Plasmodium falciparum Cytosol during Its Asexual Development in Human Erythrocytes

Mitochondrial heat shock protein 60 (Hsp60) is a nuclear encoded gene product that gets post-translationally translocated into the mitochondria. Using multiple approaches such as immunofluorescence experiments, isoelectric point analysis with two-dimensional gel electrophoresis, and mass spectrometric identification of the signal peptide, we show that Hsp60 from Plasmodium falciparum (PfHsp60) accumulates in the parasite cytoplasm during the ring, trophozoite, and schizont stages of parasite development before being imported into the parasite mitochondria. Using co-immunoprecipitation experiments with antibodies specific to cytoplasmic PfHsp90, PfHsp70-1, and PfHsp60, we show association of precursor PfHsp60 with cytoplasmic chaperone machinery. Metabolic labeling involving pulse and chase indicates translocation of the precursor pool into the parasite mitochondrion during chase. Analysis of results obtained with Geldanamycin treatment confirmed precursor PfHsp60 to be one of the clients for PfHsp90. Cytosolic chaperones bind precursor PfHsp60 prior to its import into the mitochondrion of the parasite. Our data suggests an inefficient co-ordination in the synthesis and translocation of mitochondrial PfHsp60 during asexual growth of malaria parasite in human erythrocytes.     

A Novel C-Terminal Homologue of Aha1 Co-Chaperone Binds to Heat Shock Protein 90 and Stimulates Its ATPase Activity in Entamoeba histolytica

Cytosolic heat shock protein 90 (Hsp90) has been shown to be essential for many infectious pathogens and is considered a potential target for drug development. In this study, we have carried out biochemical characterization of Hsp90 from a poorly studied protozoan parasite of clinical importance, Entamoeba histolytica. We have shown that Entamoeba Hsp90 can bind to both ATP and its pharmacological inhibitor, 17-AAG (17-allylamino-17-demethoxygeldanamycin), with K_d values of 365.2 and 10.77 μM, respectively, and it has a weak ATPase activity with a catalytic efficiency of 4.12 × 10^− 4 min^− 1 μM^− 1. Using inhibitor 17-AAG, we have shown dependence of Entamoeba on Hsp90 for its growth and survival. Hsp90 function is regulated by various co-chaperones. Previous studies suggest a lack of several important co-chaperones in E. histolytica. In this study, we describe the presence of a novel homologue of co-chaperone Aha1 (activator of Hsp90 ATPase), EhAha1c, lacking a canonical Aha1 N-terminal domain. We also show that EhAha1c is capable of binding and stimulating ATPase activity of EhHsp90. In addition to highlighting the potential of Hsp90 inhibitors as drugs against amoebiasis, our study highlights the importance of E. histolytica in understanding the evolution of Hsp90 and its co-chaperone repertoire.     

The siderophore ferricrocin produced by specific foliar endophytic fungi in vitro

Production of extracellular siderophores is typical for many plant-associated microbes, both mutualistic and antagonistic. Various strains of mycorrhizal fungi produce siderophores, and siderophore production by pathogenic fungi is typically associated with virulence. We analyzed extracellular siderophore production along with production of antibacterial and antioxidant compounds in foliar endophytic fungi of Scots pine (Pinus sylvestris L.) and Labrador tea (Rhododendron tomentosum Harmaja). The siderophore produced in vitro was ferricrocin, quantities ranging between 7.9 and 17.6 μg/l. Only the fungi with antibacterial activity produced ferricrocin and any well-known siderophores were not detected in the broths of antioxidant-producing fungi. Therefore, production of ferricrocin is typical for some, but not all foliar endophytic fungi. Ferricrocin was detected in the leaves of Labrador tea, which suggests that ferricrocin may play a role in vivo in the interaction between the endophyte and plant host.     

Heat Shock Protein 90 as a Drug Target against Protozoan Infections: BIOCHEMICAL CHARACTERIZATION OF HSP90 FROM PLASMODIUM FALCIPARUM AND TRYPANOSOMA EVANSI AND EVALUATION OF ITS INHIBITOR AS A CANDIDATE DRUG*

Using a pharmacological inhibitor of Hsp90 in cultured malarial parasite, we have previously implicated Plasmodium falciparum Hsp90 (PfHsp90) as a drug target against malaria. In this study, we have biochemically characterized PfHsp90 in terms of its ATPase activity and interaction with its inhibitor geldanamycin (GA) and evaluated its potential as a drug target in a preclinical mouse model of malaria. In addition, we have explored the potential of Hsp90 inhibitors as drugs for the treatment of Trypanosoma infection in animals. Our studies with full-length PfHsp90 showed it to have the highest ATPase activity of all known Hsp90s; its ATPase activity was 6 times higher than that of human Hsp90. Also, GA brought about more robust inhibition of PfHsp90 ATPase activity as compared with human Hsp90. Mass spectrometric analysis of PfHsp90 expressed in P. falciparum identified a site of acetylation that overlapped with Aha1 and p23 binding domain, suggesting its role in modulating Hsp90 multichaperone complex assembly. Indeed, treatment of P. falciparum cultures with a histone deacetylase inhibitor resulted in a partial dissociation of PfHsp90 complex. Furthermore, we found a well known, semisynthetic Hsp90 inhibitor, namely 17-(allylamino)-17-demethoxygeldanamycin, to be effective in attenuating parasite growth and prolonging survival in a mouse model of malaria. We also characterized GA binding to Hsp90 from another protozoan parasite, namely Trypanosoma evansi. We found 17-(allylamino)-17-demethoxygeldanamycin to potently inhibit T. evansi growth in a mouse model of trypanosomiasis. In all, our biochemical characterization, drug interaction, and animal studies supported Hsp90 as a drug target and its inhibitor as a potential drug against protozoan diseases.     

Large-scale spatial synchrony in red squirrel populations driven by a bottom-up effect

Oecologia - Spatial synchrony between populations emerges from endogenous and exogenous processes, such as intra- and interspecific interactions and abiotic factors. Understanding factors...     

Modelling irruptions and population dynamics of the great spotted woodpecker – joint effects of density and cone crops

Irruptive migrants are partially migrating species showing pronounced temporal variation in the number of migrants. Occasional irruptions are often explained by increased population density (per area) or lack of food. Similarly to population dynamics, these explanations are not mutually exclusive, but probably act in concert. Here we do a parallel analysis on the migration intensity and population dynamics of an irruptive migratory bird species, the great spotted woodpecker Dendrocopos major, in southern Finland. Both analyses include simultaneous effects of breeding density and cone crops of Scots pine Pinus sylvestris and Norway spruce Picea abies. A novel model for statistical analyses of irruptive migration intensity is developed. Population dynamics are investigated using log‐linear state‐space models. Woodpecker migration intensity is well explained by lack of spruce cones and increases proportionally to population density. Population dynamics is most successfully described with a density dependent model, where the natural logarithm of spruce cone availability previous autumn has a strong positive effect on population growth. This is likely to be due to lowered winter mortality and lowered emigration rates resulting from plentiful food availability. Although the species uses pine cones as a food resource in winter, the estimated impacts of pine cone crops on migration intensity and population dynamics are low, probably due to low annual variation in crop comparing to spruce cones. Large irruptions also tend to occur earlier in season, often before cones are a crucial food resource for the woodpeckers, suggesting that the woodpeckers use the amount of maturing cones as a cue for upcoming conditions. Our results show that the ecological role of different resources can differ considerably from the expected pattern based on the proportion of the resources in a species’ diet. Advantages of examining patterns of bird migration, population density and dynamics in unison are apparent.