Succession of Microbial Decomposers Is Determined by Litter Type, but Site Conditions Drive Decomposition Rates.

Soil microorganisms are diverse, although they share functions during the decomposition of organic matter. Thus, preferences for soil conditions and litter quality were explored to understand their niche partitioning. A 1-year-long litterbag transplant experiment evaluated how soil physicochemical traits of contrasting sites combined with chemically distinct litters of sedge (S), milkvetch (M) from a grassland, and beech (B) from forest site decomposition. Litter was assessed by mass loss; C, N, and P contents; and low-molecular-weight compounds. Decomposition was described by the succession of fungi, Actinobacteria, Alphaproteobacteria, and Firmicutes; bacterial diversity; and extracellular enzyme activities. The M litter decomposed faster at the nutrient-poor forest site, where the extracellular enzymes were more active, but microbial decomposers were not more abundant. Actinobacteria abundance was affected by site, while Firmicutes and fungi by litter type and Alphaproteobacteria by both factors. Actinobacteria were characterized as late-stage substrate generalists, while fungi were recognized as substrate specialists and site generalists, particularly in the grassland. Overall, soil conditions determined the decomposition rates in the grassland and forest, but successional patterns of the main decomposers (fungi and Actinobacteria) were determined by litter type. These results suggest that shifts in vegetation mostly affect microbial decomposer community composition.IMPORTANCE Anthropogenic disturbance may cause shifts in vegetation and alter the litter input. We studied the decomposition of different litter types under soil conditions of a nutrient-rich grassland and nutrient-poor forest to identify factors responsible for changes in the community structure and succession of microbial decomposers. This will help to predict the consequences of induced changes on the abundance and activity of microbial decomposers and recognize if the decomposition process and resulting quality and quantity of soil organic matter will be affected at various sites.

Sequential analysis of soil factors related to common scab of potatoes.

The severity of common scab (CS) of potatoes has been correlated with multiple environmental factors. This study aimed at separating the effect of factors related to local conditions from those correlated to the disease development at all studied sites using a mathematical adjustment of the variables' means for site and field. The experiment was conducted at two sites differing in soil conditions, where a field with low disease severity occurs next to one with high severity. Three cultivars susceptible to CS were grown in four replicates on each field. Bacteria, actinobacteria and the txtB gene, involved in the biosynthesis of the main CS pathogenicity factor, thaxtomin, were quantified by real-time PCR. Bulk soil, tuberosphere soil and potato periderm were characterized by carbon, nitrogen, phosphorus, sulfur, calcium, magnesium and iron contents. The adjustment of the data for field effects eliminated the confounding local conditions and showed that at all fields the CS severity was negatively correlated with soil S content while the number of txtB gene copies was positively correlated with soil C and N contents. Thus, those factors might have a more general relationship to the pathogen occurrence and disease severity, which needs to be verified in other environmental conditions.

The influence of soil organic carbon on interactions between microbial parameters and metal concentrations at a long-term contaminated site.

The effects of lead, zinc, cadmium, arsenic and copper deposits on soil microbial parameters were investigated at a site exposed to contamination for over 200 years. Soil samples were collected in triplicates at 121 sites differing in contamination and soil organic carbon (SOC). Microbial biomass, respiration, dehydrogenase activity and metabolic quotient were determined and correlated with total and extractable metal concentrations in soil. The goal was to analyze complex interactions between toxic metals and microbial parameters by assessing the effect of soil organic carbon in the relationships. The effect of SOC was significant in all interactions and changed the correlations between microbial parameters and metal fractions from negative to positive. In some cases, the effect of SOC was combined with that of clay and soil pH. In the final analysis, dehydrogenase activity was negatively correlated to total metal concentrations and acetic acid extractable metals, respiration and metabolic quotient were to ammonium nitrate extractable metals. Dehydrogenase activity was the most sensitive microbial parameter correlating most frequently with contamination. Total and extractable zinc was most often correlated with microbial parameters. The large data set enabled robust explanation of discrepancies in organic matter functioning occurring frequently in analyzing of contaminated soil processes.

[Relationship between the levels of toxic polychlorinated biphenyls in blood and follicular fluid of sterile women]. / Vztah mezi hladinami toxických polychlorovaných bifenylu v krvi a ve folikulární tekutine sterilních zen.

OBJECTIVE: The aim of this study was to confirm the possibility of detection of toxic polychlorinated biphenyls in blood and follicular fluid of infertile women undergoing IVF+ET program and determine the levels of some congeners. To confirm their cumulation in follicular fluid. DESIGN: Pilot study. SETTING: Department of Obstetrics and Gynecology, 1st Faculty of Medicine, Charles University and General Faculty Hospital, Prague, AXYS Varilab s.r.o., Vrané nad Vltavou, Institute of Hygieny and Epidemiology, 1st Faculty of Medicine Charles University and General Faculty Hospital, Prague, Euromise Centrum, Charles University, Prague. METHODS: We detected the level of polychlorinated biphenyls in blood and follicular fluid of infertile women undergoing IVF+ET program. We recieved the follicular fluid by transvaginal punction of follicles under ultrasonography control. The blood was taken before begining of anestezia. The follicular fluid and blood were frozen and transported to the laboratory. The samples were examined there by methods of gas chromatography and mass spectrometry. We were able to find all PCBs with 3-7 atoms of chlorine. RESULTS: We confirmed the possibility of detection of polychlorinated biphenyls (PCBs) in blood and follicular fluid of infertile women. We examineted the levels of PCB 77, 81, 105, 114, 118+123, 126, 156, 157, 167, 169, 189. The levels of PCBs were in ng/gram of fat. The levels of polychlorinated biphenyls differed from 0 to 400 ng/g of fat. Statistical analysis was made by t test a Wilcox test. All PCBs are cumulated in follicular fluid, except of PCB 126. CONCLUSION: The possibility of detection of PCBs in blood and follicular fluid of infertile women undergoing IVF+ET program was confirmed. The cumulation of these xenobiotics in follicular fluid was found. In the future we will analyse the relationship between the presence of these xenobiotics and achieving succesful pregnancy.

[Differences in the polychlorinated biphenyl levels in follicular fluid in individual types of sterility]. / Jak se lisí hladiny polychlorovan ch bifenylu ve folikulární tekutine u jednotlivých typu sterilit?

OBJECTIVE: To find the differences of polychlorinated biphenyls (PCBs) levels in follicular fluid in different indications to treatment with IVF + ET program. DESIGN: Pilot study. SETTING: Department of Obstetrics and Gynecology, 1st Faculty of Medicine, Charles University and General Faculty Hospital, Prague, AXYS Varilab, s.r.o., Vrané nad Vltavou, Prague, Euromise Centrum, Charles University and Academy of Art, Prague. METHODS: We examinated 100 infertile women undergoing IVF + ET program in our pilot study. After ovarian pick-up, frozen follicular fluid were transported to the laboratory. We detected the levels of polychlorinated biphenyls in follicular fluid of infertile women. The levels were compared according to the different indications of treatment. The control group consist of patients with male factor of sterility. RESULTS: We confirmed the higher levels of PCB 114, 153, 156, 157, 180 and 189 in indication endometriosis compared with the others and with control group. The levels of PCBs were in ng/gram of fat. CONCLUSION: It has become apparent that higher levels of PCB 114, 153, 156, 157, 180 and 189 in endometriosis patients may be one of many factors participating in the origin of the disease.

[Comparison of organochlorine pesticide levels in blood and follicular fluid of infertile women]. / Porovnání hladin organochlorovaných pesticidu v krvi a ve folikulární tekutine neplodných zen.

OBJECTIVE: The aim of this study was to detect DDT and its metabolites, lindane and its conformers (alfa, beta, gama and delta conformers of hexachlorocyklohexane - HCH) and hexacyclobenzene (HCB) in blood and follicular fluid of infertile women undergoing IVF+ET program. In the case if their detection, to confirm their cumulation in follicular fluid. DESIGN: Pilot study. SETTING: Department of Obstetrics and Gynecology, 1st Faculty of Medicine, Charles University and General Faculty Hospital, Prague, AXYS Varilab s.r.o., Vrané nad Vltavou, Institute of Hygiene and Epidemiology, 1st Faculty of Medicine Charles University and General Faculty Hospital, Prague, Euromise Centrum, Charles University and Academy of Arts, Prague, Czech republic. METHODS: We detected the level of DDT, DDE, DDD, lindane and its conformers (alfa, beta, gama and delta conformers of hexachlorocyklohexane - HCH) and hexacyclobenzene (HCB) in blood and folicular fluid of 30 infertile women undergoing IVF + ET program. We recieved the follicular fluid by transvaginal punction of follicular fluid under ultrasonography control. The venous blood was taken before begining of anestesia. The follicular fluid and blood were frozen and transported to the laboratory. There the samples were examinated by the methods of gass chromatography and mass spectrometry. RESULTS: We confirmed the possibility of detection of DDT, DDE, DDD, lindane and its conformers (alfa, beta, gama and delta conformers of hexachlorocyclohexane - HCH) and hexacyclobenzene (HCB) in blood and follicular fluid of infertile women. The differences in concentrations in blood and follicular fluid were statistically analysed. We confirmed the cumulation of DDT, DDE, DDD, lindane and its conformers (alfa, beta, gama and delta conformers of hexachlorocyclohexane - HCH) and hexacyclobenzene (HCB) in follicular fluid of infertile women. The levels of these compounds in blood differed from 2.8 to 6399.3 ng/g of fat, in follicular fluid from 1.4 to 4 099.8 ng/g of fat. CONCLUSION: It is possible to detect DDT, DDE, DDD, lindane and its conformers (alfa, beta, gama and delta conformers of hexachlorocyclohexane - HCH) and hexacyclobenzene (HCB) in blood and follicular fluid of infertile women. The cumulation of these xenobiotics in follicular fluid was found.