Seasonal patterns of cellulase concentration in desert soil

The concentration of cellulose in plant material greatly affects the decomposition rate of plant-derived litter and hence carbon availability. The disappearance of pure cellulose in soil was studied as a measure of plant decomposition and carbon turnover. Our objective was to understand the effect of various cellulose concentrations and plant material added to soil and collected during different seasons, on cellulase concentrations under laboratory conditions (e.g. constant soil moisture and incubation temperature). The percentage of recovery of the enzyme in the control soil and in samples amended with known amounts of cellulose powder was estimated. Several methods for estimating soil cellulase concentrations/activity are available, most based on the determination of released reducing sugars. The method used in this study is based on the cleavage of a cellulose-azure substrate by cellulase to spectrophotometrically detectable fragments. Our results showed a significant correlation (p<0.05) between cellulose concentration and cellulase levels in soil, which varied along the study period. When pure cellulose was added to the soil, cellulase was detected after 7 days of incubation, whereas when plant material was added to the soil, cellulase was detected after 14 days. The recovery of cellulase from soil was also found to be seasonally dependent. The method of cellulase determination used in this study was simple, safe and rapid. From the results presented in this study, it can be assumed that there are seasonally dependent factors that affect the existence and concentration of cellulase in soils of the arid Negev Desert, in addition to organic matter, water and temperature.     

Identification of Resistance Genes Against Powdery Mildew in Four Accessions of Hordeum Vulgare SSP. Spontaneum

Summary Four newly detected accessions of wild barley (Hordeum vulgare ssp. spontaneum) resistant to powdery mildew caused by Blumeria graminis f. sp. hordei were studied with the aim of finding the number of genes/loci conferring the resistance of individual accessions, the type of inheritance of the genes and their relationships to the Mla locus. F₂ populations after crosses between the winter variety ‘Tiffany’ and four wild barley accessions and use of microsatellite DNA markers were focused on the identification of individual resistance genes/loci by means of their chromosomal locations. In PI466495, one locus conferring powdery mildew resistance was identified in highly significant linkage with the marker Bmac0213. This location is consistent with the known locus Mla on chromosome 1HS. In the other three accessions the resistance was determined by two independent loci. In PI466197, PI466297 and PI466461, one locus was identified on chromosome 1HS and three new loci were revealed on chromosomes 2HS (highly significant linkage with Bmac0134), 7HS (highly significant linkage with Bmag0021) and 7HL (significant linkage with EBmac0755). Our prospective aim is identification of further linked DNA markers and the exact location of the resistance genes on the barley chromosomes.     

Adaptation of wheat rusts to the wheat cultivars in former Czechoslovakia

Summary In former Czechoslovakia virulence of rusts attacking wheat was studied since the sixties. Since the same time genes for resistance in the registered cultivars were identified. The role of Berberis and Thalictrum as alternate hosts for stem rust and leaf rust, respectively, was investigated as well. Determined changes of virulence in rust populations could only partially be ascribed to changes of resistance genes in the grown cultivars. Unnecessary genes for virulence had no negative effect on the fitness of the pathogen. All tested samples of aeciospores from barberries attacked rye, not wheat. None of Thalictrum species occurring in the Czech and Slovak Republics was found to host wheat leaf rust. However, the sexual stage of wheat stem rust and wheat leaf rust could be induced on Berberis vulgaris and Thalictrum speciosissimum, respectively. General epidemiological conclusions are drawn from the results and experience of the last 35 years.     

Success of nursing ide (Leuciscus idus, L.) fry related to the period of feeding with live food

The ide Leuciscus idus (Linnaeus 1758) belongs to autochthonous, less frequent and vulnerable fish species in the frame of ichthyofauna of the Czech Republic. It was the reason for testing the possibility of captive breeding and production of fry in a controlled environment. The goal of this paper was to find the optimal transfer time of ide larvae from live food (Artemia salina nauplii) to dry starter feed providing good survival and growth. At the end of the experiment, high values of cumulative survival (in percentages) and individual weight (in milligrammes) were found for ide fry in groups D (90.6%, 178.6 mg; 15 days A. salina + 10 days starter feed), A (89.9%, 169.9 mg; A. salina only) and C (88.6%, 160.4 mg; 10 days A. salina + 15 days starter feed). Significantly lower values of the given parameters were found in group B (57.1%, 92.6 mg; 5 days A. salina + 20 days starter feed), and the lowest ones were in group E (29.8%, 75.6 mg; starter feed only). Mean values of the level of ontogenesis at the end of the experiment in fry of A–E groups were analogous to length and weight growth. Groups D, C and A consisted of juveniles only (J1, J2), and groups B and E consisted of larvae and juveniles (L4, L5, L6, J1, J2). Condition and production parameters [Fulton’s coefficient of condition (FWC), total length (TL), weight (w), specific growth rate (SGR), food conversion ratio (FCR), cumulative survival] and relationships between basic lengths TL, fork length (FL) and standard length (SL) were evaluated.     

Identification of species-specific DNA in feedstuffs

Due to the menace of transmission of spongiform encephalopathies, feed components intended for ruminant nutrition must be checked for the presence of ruminant-derived materials. A sensitive method for the identification of bovine- and ovine- and also swine- and chicken-specific mitochondrial DNA sequences based on Polymerase Chain Reaction (PCR) has been developed. The specificity of the primers for PCR has been tested using samples of DNA of other vertebrate species, which may also be present in rendering plant products intended for feed manufacture. The method allows the detection in concentrate mixtures of 0.01% of the target species derived material. The identity of a sample containing 0.1% of bovine, ovine, swine, and chicken meat-and-bone meal has further been confirmed by sequencing.     

Manganese Biogeochemistry in a Central Czech Republic Catchment

Mn biogeochemistry was studied from 1994 to 2003 in a small forested catchment in the central Czech Republic using the watershed mass balance approach together with measurements of internal stores and fluxes. Mn inputs in bulk deposition were relatively constant during a period of sharply decreasing acidic deposition, suggesting that the Mn source was terrestrial, and not from fossil fuel combustion. Mn inputs in bulk deposition and Mn supplied by weathering each averaged 13 mg m^?2 year^?1 (26 mg m^?2 year^?1 total input), whereas Mn export in streamwater and groundwater averaged 43 mg m^?2 year^?1. Thus an additional Mn source is needed to account for 17 mg m^?2 year^?1. Internal fluxes and pools of Mn were significantly greater than annual inputs and outputs. Throughfall Mn flux was 70 mg m^?2 year^?1, litterfall Mn flux was 103 mg m^?2 year^?1, and Mn net uptake by vegetation was 62 mg m^?2 year^?1. Large pools of labile or potentially labile Mn were present in biomass and surficial soil horizons. Small leakages from these large pools likely supply the additional Mn needed to close the watershed mass balance. This leakage may reflect an adjustment of the ecosystem to recent changes in atmospheric acidity.     

The Impact of an Abandoned Uranium Mining Area on the Contamination of Agricultural Land in its Surroundings

This paper focuses on the influence of uranium tailing piles on the contamination of their immediate surroundings. The monitoring was carried out on arable land near Pribram in Central Bohemia, Czech Republic. The monitored arable land is located 600 m northeast of the bottom of the piles. In addition, the high uranium (U) content in the topsoil ranged from 40 to 220 ppm. A former portion of it was found in an exchangeable fraction (49%). Both of these facts make this land unsuitable for agricultural use. The sequential extraction discovered a shift in the U content among sample spots situated in and outside the path of the predominant wind direction. In the first group, uranium binds mainly to Fe/Mn oxides, while in the other samples, U is accumulated in the more mobilizable fractions.     

CONGENITAL ABNORMALITIES OF THE VERTEBRAL COLUMN IN FERRETS

Vertebral column pathologies requiring surgical intervention have been described in pet ferrets, however little information is available on the normal vertebral formula and congenital variants in this species. The purpose of this retrospective study was to describe vertebral formulas and prevalence of congenital vertebral anomalies in a sample of pet ferrets. Radiographs of 172 pet ferrets (96 males and 76 females) were included in this retrospective study. In 143 ferrets (83.14%), five different formulas of the vertebral column were recorded with normal morphology of vertebrae (rib attachment included) but with a variable number of thoracic (Th), lumbar (L), and sacral (S) vertebrae. The number of cervical (C) vertebrae was constant in all examined animals. Observed vertebral formulas were C7/Th14/L6/S3 (51.74%), C7/Th14/L6/S4 (22.10%), C7/Th14/L7/S3 (6.98%), C7/Th15/L6/S3 (1.74%), and C7/Th15/L6/S4 (0.58%). Formula C7/Th14/L6/S4 was significantly more common in males than in females (P < 0.05). Congenital spinal abnormalities were found in 29 ferrets (16.86%), mostly localized in the thoracolumbar and lumbosacral regions. The cervical region was affected in only one case. Transitional vertebrae represented the most common congenital abnormalities (26 ferrets) in the thoracolumbar (13 ferrets) and lumbosacral regions (10 ferrets) or simultaneously in both regions (three ferrets). Other vertebral anomalies included block (two ferrets) and wedge vertebra (one ferret). Spina bifida was not detected. Findings from the current study indicated that vertebral formulas may vary in ferrets and congenital abnormalities are common. This should be taken into consideration for surgical planning.