Clavibacter michiganensis subsp. michiganesis: Tracking strains using their genetic differentiations by ISSR markers in Southern Turkey

There is no available data published related to the dissemination of bacterial canker caused by Clavibacter michiganensis subsp. michiganensis (Cmm) and its genetic diversity in Turkey. It is important to control new introduced inoculum sources by commercial seeds and seedlings. Pathogens were identified by morphological features and the identity was confirmed by PCR amplification using a specific primer PSA-4, PSA-R in addition to microbiological tests. ISSR markers showing high polymorphism ratios were selected and used to characterize Cmm strains. The collected strains were classified into different groups on the basis of ISSR-PCR fingerprints, which showed remarkable genetic specificity and diversity not previously identified in Cmm, suggesting that genetic differences are related to dissemination of the pathogen in the region. This is the first ever study carried out on the characterization of Cmm using ISSR. The selected ISSR primers to characterize Cmm can be used to determine genetic differences in further studies.     

Pheno- and genotyping of Staphylococcus epidermidis isolated from bovine milk and human skin

The purpose of this study was to improve our knowledge concerning the epidemiology and strain diversity of Staphylococcus epidermidis isolated from bovine milk in commercial dairy herds. A total of 341 S. epidermidis isolates obtained from cows' milk (317), farmers (17) and patients (7) were characterized. Of these 105 isolates were from cows' milk in two farms, where also 17 isolates were sampled from farmers. The remaining 212 isolates from cows' milk were from 170 farms. All isolates were examined by antimicrobial susceptibility, whereas 202 were examined by pulsed-field gel electrophoresis (PFGE) and 122 by ribotyping. PFGE showed single patterns in the human strains with one exception; one strain was categorised as the same clone as four of the milk strains. PFGE divided 73 of the milk strains into 62 different patterns. The PFGE method had high discriminatory power and shows that many different S. epidermidis types exist in milk samples. Antibiotic resistance patterns matched the SmaI profiles closely in the two herds, but poorly in the routinely collected milk samples. Isolates from herd 1 showed one to five patterns, depending on the typing method used. Isolates from the milker's skin showed one pattern, which was identical to the most common pattern found in the milk isolates. Isolates from herd 2 showed three to four patterns, two of these being identical to skin isolates from the milker. As dairy cows are not a natural host for S. epidermidis the results suggest a human source of these udder infections.     

Onset of sexual maturity in female chickens is genetically linked to loci associated with fecundity and a sexual ornament

Onset of sexual maturation is a trait of extreme importance both evolutionarily and economically. Unsurprisingly therefore, domestication has acted to reduce the time to sexual maturation in a variety of animals, including the chicken. In comparison with wild progenitor chickens [the Red Junglefowl (RJF)], domestic layer hens attain maturity approximately 20% earlier. In addition, domestic layers also possess larger combs (a sexual ornament), produce more eggs and have denser bones. A large quantitative trait loci (QTL) analysis (n=377) was performed using an F(2) intercross between a White Leghorn layer breed and a RJF population, with onset of sexual maturity measured and mapped to three separate loci. This cross has already been analysed for comb mass, egg production and bone allocation. Onset of sexual maturity significantly correlated with comb mass, whilst the genetic architecture for sexual maturity and comb mass overlapped at all three loci. For two of these loci, the QTL for sexual maturity and comb mass were statistically indistinguishable from pleiotropy, suggesting that the alleles that increase comb mass also decrease onset of sexual maturity.     

Effects of oral supplementation of probiotic strains of Lactobacillus rhamnosus and Enterococcus faecium on diarrhoea events of foals in their first weeks of life

Foal first diarrhoea is one of the most prominent problems in the early life of horses. Probiotics might have the potency to prevent or at least diminish neonatal diarrhoea. We hypothesised that the treatment of foals with probiotic strains of Lactobacillus rhamnosus and Enterococcus faecium starting early after birth and then daily over 2 weeks would prevent or mitigate foal heat diarrhoea. The influence of this probiotic treatment on diarrhoea incidence and growth and health performance of young foals was investigated. Thirty‐four foals were randomly allocated to two groups. From day 1 to 14 of life, the foals received either placebo (PG, n = 16) or the probiotic treatment (TG, n = 18). Clinical examination was performed, and the faeces consistency score (FCS, 1–5; with diarrhoea defined by ≤3) was recorded once per day in weeks 1 and 2 and once weekly in weeks 3–8 of life (WL). The body height was measured at birth and after two and eight WL. Diarrhoea occurred in the 1st WL in 19% and 61% of PG and TG foals respectively. In the 1st WL, diarrhoea lasted 0.3 ± 0.8 and 1.6 ± 1.4 days in PG and TG foals respectively. In the 2nd WL, diarrhoea occurred in 94% and 84% of PG and TG foals, respectively, and lasted for 3.0 ± 1.5 and 3.7 ± 1.6 days respectively. At least two periods of diarrhoea developed in 33% and 65% of PG and TG foals respectively. The TG foals grew slightly slower than the PG foals. The results indicated that the probiotic treatment of neonatal foals as performed in this study was not suitable to reduce diarrhoea within the first two WL, because contrary to the hypothesis, the TG foals suffered more frequently and for longer periods from diarrhoea than the PG foals.     

Fibril angle variability in earlywood of Norway spruce using soft rot cavities and polarization confocal microscopy

The main purpose of this study was to investigate the variability of the fibril angle of tracheids in earlywood of Norway spruce (Picea abies L. Karst.). Polarization confocal microscopy was chosen and compared with the method utilizing the orientation of soft rot cavities. There was a significant correlation between the soft rot and polarization confocal microscopy methods, which showed the same trend of high fibril angles in the first part of the earlywood followed by a decrease toward the end of earlywood. This declining trend was less pronounced in annual rings containing compression wood. Moreover, large variations in fibril angle occurred between neighboring tracheids. The investigation also emphasized the differences between X-ray diffraction and microscopic methods, as the large variation seen by the latter methods is not seen by the X-ray diffraction approach because of its large area of measurement. No correlation was found between fiber morphology (i.e., average length, width, density) and the average fibril angle in the investigated annual rings.     

Effect of Biochar Amendment and Ageing on Adsorption and Degradation of Two Herbicides

Biochar amendment can alter soil properties, for instance, the ability to adsorb and degrade different chemicals. However, ageing of the biochar, due to processes occurring in the soil over time, can influence such biochar-mediated effects. This study examined how biochar affected adsorption and degradation of two herbicides, glyphosate (N-(phosphonomethyl)-glycine) and diuron (3-(3,4-dichlorophenyl)-1,1-dimethylurea) in soil and how these effects were modulated by ageing of the biochar. One sandy and one clayey soil that had been freshly amended with a wood-based biochar (0, 1, 10, 20 and 30% w/w) were studied. An ageing experiment, in which the soil-biochar mixtures were aged for 3.5 months in the laboratory, was also performed. Adsorption and degradation were studied in these soil and soil-biochar mixtures, and compared to results from a soil historically enriched with charcoal. Biochar amendment increased the pH in both soils and increased the water-holding capacity of the sandy soil. Adsorption of diuron was enhanced by biochar amendment in both soils, while glyphosate adsorption was decreased in the sandy soil. Ageing of soil-biochar mixtures decreased adsorption of both herbicides in comparison with freshly biochar-amended soil. Herbicide degradation rates were not consistently affected by biochar amendment or ageing in any of the soils. However, glyphosate half-lives correlated with the Freundlich Kf values in the clayey soil, indicating that degradation was limited by availability there.     

Antifungal activity toPhytophthora infestans of sesquiterpenoids from infected potato tubers

Summary The sesquiterpenes 2-(1',2'-dihydroxy-1'-methylethyl)-6,10-dimethyl-spiro-[4,5]dec-6-en-8-on (1) and its 2'-O-β-d-glucopyranoside (2) were isolated from the stress zones of potato tubers infected withPhoma foveata andFusarium spp., and rishitin and solavetivone from tuber slices inoculated withErwinia carotovora. The influence of these compounds, and of the naturally occurring plant sesquiterpenoids abscisic acid, cedrol and farnesol, on the mycelial growth ofPhytophthora infestans were tested on agar plates using a defined medium. All sesquiterpenoids suppressed the growth of the pathogen, except for1 and its glucoside2 which induced a slight, however significant, growth stimulation. Compounds1 and2 could not be isolated fromE. carotovora orP. infestans-inoculated tuber tissue.     

Influence of Harvest Time and Stubble Height on Weed Seedling Recruitment in a Green Cereal

A long-term field experiment was conducted in southern Sweden to evaluate the effect of harvest before crop ripeness on weed infestation. In addition, two stubble heights, 10 cm and 30 cm, were compared. The aim was to determine the potential of the treatments in weed regulation. The harvests were performed on three occasions: milk-ripeness (I), which is the normal harvest time for a green cereal, yellow-ripeness (II) and binder-ripeness (III). In control plots, harvested at full ripeness, herbicides were used in all years. Weed density initially increased exponentially in all treatments except for the control, but had a tendency to level off after 4 years. In all years weed density was higher when harvest was delayed and the stubble was high. Harvest at milk ripeness (I) favoured short-season annuals such as Stellaria media (L) Vill and worked against late-maturing species such as Polygonum tomentosum (Schrank). Weed density differed between the treatment plots during the last year of the experiment. In the treatment harvested at stage I combined with low stubble height, weed density was only slightly higher than in the control. Thus, when harvesting a green cereal, herbicides can be avoided.     

Gene flow in common bean (Phaseolus vulgaris L.)

This study was conducted in Brazil in order to assess the potential risk posed by gene escape from transgenic into non-transgenic plants and wild populations. A new methodology was applied to evaluate the gene flow between common bean cultivars, by means of a specially delineated experiment in two stages. The first stage consisted of the planting of one cultivar with violet flowers (BB) as pollen source (‘Diamante Negro’), and a receiver (‘Talismã’) with white flowers (bb), at different distances. The source was sown in the center of the area. The pollen receiver cultivar was sown, in concentrical squares around it. At maturity, the rows were sampled at varied distances from the source in the four cardinal directions. In the second stage, the sampled seeds of the previous stage were sown, and the percentage of outcrossing was evaluated during flowering through the presence of violet flowers (Bb). The highest frequency of natural hybrids, 0.136%, occurred at a distance of 0.5 m between the cultivars. The natural outcrossing rate was practically zero beyond a distance of 3.25 m.