Armillaria ostoyae associated with dying 60‐year‐old Scots pines in northern Turkey

We investigated an Armillaria root disease centre in a 60‐year‐old, naturally regenerated Pinus sylvestris stand located at 1250 m altitude in Sinop province in northern Turkey. Based on sequence analysis of the internal transcribed spacer region of the rDNA, the mycelial fans sampled from the infected trees were Armillaria ostoyae. Multilocus genotyping indicated that the fans belonged to a single genet, at least 0.2 ha in size. Drought as a predisposing factor is discussed. The study area received 50–70 and 25–50% of the normal precipitation in May, June and August in 2009 and in August and September in 2010, respectively. Moreover, earlier excavation work to prepare a forest road had probably disrupted the water table in the affected stand.     

Detection of feline coronavirus infection in captive cheetahs (Acinonyx jubatus) by polymerase chain reaction.

Feline coronavirus genetic elements were detected by polymerase chain reaction from blood, fecal samples, and effusive fluid collected from 33 cheetahs in the U.S.A. Feline coronavirus-specific serum antibodies were also measured by indirect immunofluorescence. Ten cheetahs were positive for viral shedding by polymerase chain reaction, whereas 13 were seropositive by immunofluorescence. Results of serology did not consistently correlate with shedding of virus, and the capture antigen used for detection of feline coronavirus-specific antibodies had a significant impact on results. Testing of samples from one population over a 1-yr period indicated chronic infection in some animals. These relatively healthy carrier animals were a source of virus for contact animals. Screening programs in cheetah populations for feline coronavirus infection may be most reliable if a combination of serologic analysis and viral detection by polymerase chain reaction is used.     

Horseradish peroxidase-catalyzed cross-linking of feruloylated arabinoxylans with beta-casein

Heterologous conjugates of wheat arabinoxylan and beta-casein were prepared via enzymatic cross-linking, using sequential addition of the arabinoxylan to a mixture of beta-casein, peroxidase, and hydrogen peroxide. The maximal formation of adducts between the beta-casein and the feruloylated arabinoxylan was reached at a protein-to-arabinoxylan ratio of 10:1, in combination with a molar ratio hydrogen peroxide to substrate of 2:1 and a molar protein-to-enzyme ratio between 10(2) and 10(4). The protein-arabinoxylan adducts were separated from the arabinoxylan homopolymers by size exclusion and anion exchange chromatography. The molar ratio protein:arabinoxylan in the purified conjugates varied between 0.1 and 5.6. This is the first report on the large-scale enzymatic preparation of heterologous protein-arabinoxylan conjugates.     

Sequence-selective recognition of DNA by strand displacement with a thymine-substituted polyamide

A polyamide nucleic acid (PNA) was designed by detaching the deoxyribose phosphate backbone of DNA in a computer model and replacing it with an achiral polyamide backbone. On the basis of this model, oligomers consisting of thymine-linked aminoethylglycyl units were prepared. These oligomers recognize their complementary target in double-stranded DNA by strand displacement. The displacement is made possible by the extraordinarily high stability of the PNA-DNA hybrids. The results show that the backbone of DNA can be replaced by a polyamide, with the resulting oligomer retaining base-specific hybridization.     

Cobalt reduces nitrate inhibition of nodulation in mungbean (Vigna radiata)

 A cobalt-mediated decrease in ethylene production reduced the inhibition of nodulation by nitrate in Vigna radiata (mungbean). Nitrate increased the ethylene production in 5-day-old seedlings, while it caused a reduction in the nodulation status (nodule number and nodule weight) and nodule efficiency (acetylene reduction activity) in mungbean plants. The application of cobalt chloride inhibited nitrate-affected ethylene production and also decreased the inhibitory effect of nitrate on nodulation. The effect of cobalt was most marked on nodule number. Received: 6 August 1999