Effects of soil properties and trace metals on urease activities of calcareous soils

A study was conducted to investigate the relationship between urease activity and some physical, chemical, and microbiological properties of soils from central Iran. Inhibitory effects of Cr, Cd, and Pb on urease activity were also studied. Results indicated that no significant difference was observed between urease activity of field-moist and air-dried soils. Soil organic C and total N correlated highly significantly with urease activity, with r values of 0.899*** and 0.797***, respectively. There was also a significant correlation between urease activity and the number of bacteria grown on urea-agar media, with r value of 0.470*. A significant negative correlation (r =–0.492*) was observed between urease activity and electrical conductivity of saturation paste extracts. There were no significant correlations between urease activity and soil textural properties, pH, calcium carbonate equivalent, cation exchange capacity, and populations of soil bacteria on nutrient agar and population of soil fungi on potato dextrose agar. Both Cd and Pb inhibited urease activity to a similar extent and to a greater extent than did Cr.     

Suppressive effect of potassium silicate on powdery mildew of strawberry in hydroponics

From 1996 to 1997, potassium silicate (SiO₂) was tested at 0, 25, 50, and 100mgl^–1 in hydroponics to control powdery mildew. Other elements were added in the usual amounts, and the strawberries were cultivated hydroponically in a greenhouse for 4 months (from October to January). The powdery mildew spread in the control plot, but little mildew developed in the plot with 25mgl^–1 silicate, and none in plots with more than 50mgl^–1 silicate. The suppressive effect lasted for about 4 months on fruits and even longer on leaves. On analysis of mineral content in the leaves, only the silicate content differed markedly between the control and treated plants. Nitrogen, phosphate, potassium, and calcium contents did not differ greatly. The maximum silicate content was about 24 times that of the control, and disease severity decreased significantly when the content was more than 1.5% in the leaves. The hardness of the strawberry leaves, measured by a creep meter, was increased by the silicate treatment.     

A simplified procedure for terminal restriction fragment length polymorphism analysis of the soil bacterial community to study the effects of pesticides on the soil microflora using 4,6-dinitroorthocresol as a test case

We have studied the structural effects of application to the soil of a potentially detrimental herbicide, 4,6-dinitroorthocresol (DNOC) by analysing amplified ribosomal DNA restriction analysis (ARDRA) and terminal restriction fragment length polymorphism (T-RFLP) signatures of 16S rDNA fragments of culturable bacterial communities isolated from diluted soil suspensions. This approach has the potential to reveal changes induced by stressing the soil microflora with DNOC. This paper shows that, whereas only few changes of the ARDRA and T-RFLP profiles result from ageing of the soil, treatment of the soil with DNOC induces major modifications of these profiles. Therefore, for the practical purpose of pesticide registration, ARDRA and T-RFLP analysis performed on the dominant culturable fraction of the soil bacteria, implemented using conventional gel electrophoresis, offers the means of a routine, simple and meaningful test for detecting some of the changes affecting the structure of the soil microflora in response to pesticide application.     

Virulence factors of avian pathogenic Escherichia coli isolated from broilers from the south of Brazil

Sixty-three Escherichia coli strains isolated from broilers with respiratory problems were examined for virulence factors, hemolysin synthesis ability, motility, hemagglutination capacity, operon pap presence, colicin production, and serum resistance. The capacity to hemagglutinate guinea pig erythrocytes was found in 53 (84.1%) of the samples, but only 30 (47.6%) agglutinated chicken erythrocytes. D-mannose-sensitive hemagglutination against guinea pig erythrocytes was found in 19 (30.2%) samples and against chicken erythrocytes, in 15 (23.8%) samples, whereas the D-mannose-resistant hemagglutination with guinea pig erythrocytes was found in 34 (54%) samples, and 13 of these (20.6%) showed this characteristic against chicken erythrocytes. Operon pap, P fimbria codifier, was detected in 26 samples in a total of 34 D-mannose-resistant samples. Colicin production was observed in 55 (87.3%) of the strains, and 41.8% presented V colicin production. Of the samples analyzed, 56 (88.9%) presented serum resistance, six (9.5%) were intermediate, and only one (1.6%) was sensitive to the action of the complement. The diversity of virulence profiles detected in the samples in this study explains in part the multifactorial characteristics of avian colibacillosis.     

Expression of inducible nitric oxide synthase in macrophages inversely correlates with parasitism of lymphoid tissues in dogs with visceral leishmaniasis

Background

There are only a few studies reporting the role of nitric oxide metabolites for controlling macrophage intracellular parasitism, and these are controversial. Therefore, the present study aimed to evaluate the expression of inducible nitric oxide synthase (iNOS) in the lymph nodes and spleen of dogs affected by visceral leishmaniasis through immunohistochemistry and to determine its correlation with tissue parasite burden and serum interferon (IFN)-γ levels. Twenty-eight dogs were selected and assigned to one of two groups, symptomatic (n = 18) and asymptomatic (n = 10), according to clinical status and laboratory evaluation. A negative control group (n = 6) from a non-endemic region for visceral leishmaniasis was included as well.

Results

Parasite density (amastigotes/mm²) was similar between clinical groups in the lymph nodes (P = 0.2401) and spleen (P = 0.8869). The density of iNOS⁺ cells was higher in infected dogs compared to controls (P < 0.05), without a significant difference in lymph node (P = 0.3257) and spleen (P = 0.5940) densities between symptomatic and asymptomatic dogs. A positive correlation was found between the number of iNOS⁺ cells in lymph nodes and interferon-γ levels (r = 0.3776; P = 0.0303), and there was a negative correlation between parasites and iNOS⁺ cell densities both in lymph nodes (r = −0.5341; P = 0.0034) and spleen (r = −0.4669; P = 0.0329).

Conclusion

The negative correlation observed between tissue parasitism and the expression of iNOS may be a reflection of NO acting on the control of parasites.     

Contributions to the knowledge of conifer aphid fauna in Turkey and their zoogeographical distribution

The Aphidoidea (Homoptera) has 29 species which attack coniferous trees in Turkey. The family Aphididae has 25 (Aphidinae, 1; Lachninae, 22; Mindarinae, 2) species and the Adelgidae, 4. The tribe Cinarini in Lachninae has alone 22 species most of which are important. Especially Cinara cedri Mimeur on Cedrus libani and C. pilicornis (Hartig) on Picea spp. are harmful species. Schizolachnus pineti (Fabricius) is also very important. An Eastern Palearctic species in the tribe Macrosiphini in Aphidinae, Elatobium momii (Shinji), is numerous on Abies bornmülleriana in Bursa-Uluda forests. Pineus orientalis (Dreyfus) in the family of Adelgidae (Chermesidae) is the most destructive in our Picea orientalis forests in Artvin area (Eastern Black-Sea Section). 21 species out of 29 aphids on coniferous trees are of European origin; only 4 are Mediterranean, 2 Caucasus and Turkistan, one Eastern Palearctic and one of Cosmopolitan origin.     

海水倒灌农田水稻栽培技术示范小结

通过对2014年"威马逊"超强台风造成海水倒灌农田后的修复改良水稻栽培技术,包括品种筛选、整地、育秧、水肥管理等试验。摸索出一套海水倒灌农田的水稻高产栽培技术,解决了海水倒灌农田灾区农民的口粮问题,为今后海南沿海地区台风造成海水倒灌农田后的水稻恢复生产储备相应技术。     

Versuche mit Herbiziden in Gemeiner Ringelblume (Calendula officinalis L.) in Sachsen-Anhalt und Thüringen

Between 2000 and 2005 12 experiments with 18 herbicides were carried out in marigold in experimental stations and on marigold fields of Thuringian farms. The main objective of the tests was to get the necessary data for the authorization procedure according to the regulations of §?18 a PflSchG. Marigold plants are very susceptible against some herbicides Betanal Progress, Goltix Compact + ?l, Kontakt 320 SC, Lentagran WP und Stefes IPU. These herbicides and cause severe damages on this culture. The use oft the herbicides Bandur, BASTA and further herbicides with the active ingredient Glufosinat was authorized for the application in marigold according the regulations of §?18 a PflSchG in the past. The herbicides Devrinol FL, Fusilade MAX, Goltix 700 SC, Roundup UltraMAX und Targa Super can be used in artichoke according the regulations of §?18 b PflSchG. These herbicides aren??t enough for the chemical control of weeds likeEchinochloa spec.,Galinsoga spec., Polygonum spec. in marigold. In addition to the application of the herbicides mechanical measures are necessary.     

Biochemical response of grapevine variety ‘Chardonnay’ (Vitis vinifera L.) to infection with grapevine yellows (Bois noir)

This study was carried out on the leaves of phytoplasma susceptible grapevine variety ??Chardonnay?? (Vitis vinifera L.), and included research of the alterations in chlorophyll and carotenoid contents, contents of phenol compounds and in related enzymes activity in the phenylpropanoid pathway during the Bois noir (BN) infection. Phytoplasma-infected leaves showed reduced contents of chlorophylls and carotenoids, which promoted their susceptibility to oxidative reactions. Furthermore, modulation of flavonoid biosynthesis occurred in infected leaves, leading to an increased activity of phenylalanine ammonia lyase, chalcone synthase/chalcone isomerase, flavanone 3-hydroxylase and polyphenoloxidase, but to a decreased peroxidase activity. Phytoplasma infection led to an increase of the contents of hydroxycinnamic acids (caftaric acid, sinapic acid glucose derivate and coutaric acid), flavanols (procyanidin B1, procyanidin dimer 3, catechin, epicatechin) and flavonols (quercetin 3-O-glucuronide, quercetin 3-O-glucoside) especially in the period up to vérasion. The study demonstrated that at certain phenological key-stages infection with phytoplasma (BN) induced different alterations in enzyme activities and in the contents of biochemical compounds from primary and secondary metabolism.     

Heavy Metals in Water Percolating Through Soil Fertilized with Biodegradable Waste Materials

The influence of manure and composts on the leaching of heavy metals from soil was evaluated in a model lysimeter experiment under controlled conditions. Soil samples were collected from experimental fields, from 0- to 90-cm layers retaining the layout of the soil profile layers, after the second crop rotation cycle with the following plant species: potatoes, spring barley, winter rapeseed, and winter wheat. During the field experiment, 20 t DM/ha of manure, municipal sewage sludge composted with straw (SSCS), composted sewage sludge (SSC), dried granular sewage sludge (DGSS), “Dano” compost made from non-segregated municipal waste (CMMW), and compost made from municipal green waste (CUGW) was applied, i.e., 10 t DM/ha per crop rotation cycle. The concentrations (μg/dm³) of heavy metals in the leachate were as follows: Cd (3.6–11.5)?<?Mn (4.8–15.4)?<?Cu (13.4–35.5)?<?Zn (27.5–48.0)?<?Cr (36.7–96.5)?<?Ni (24.4–165.8)?<?Pb (113.8–187.7). Soil fertilization with organic waste materials did not contaminate the percolating water with manganese or zinc, whereas the concentrations of the other metals increased to the levels characteristic of unsatisfactory water quality and poor water quality classes. The copper and nickel content of percolating water depended on the concentration of those metals introduced into the soil with organic waste materials. The concentrations of Cd in the leachate increased, whereas the concentrations of Cu and Ni decreased with increasing organic C content of organic fertilizers. The widening of the C/N ratio contributed to Mn leaching. The concentrations of Pb, Cr, and Mn in the percolating water were positively correlated with the organic C content of soil.