An Investigation of Ovine Pneumonia in Four Herds from Central Norway

In a study of 4 sheep herds, 1 apparently healthy and 3 having respiratory problems, lesions typical of subacute or chronic pneumonia were found in 3–36 % of slaughtered lambs. Occurrence appeared to be related to certain environmental factors such as pasture, whereas moderate lungworm invasion was not found to contribute to subacute or chronic pneumonia. Relation between pneumonia and low carcass weight was established only in 1 herd. Lungs were subjected to microbiological examination. Mycoplasma ovipneumoniae was isolated from both normal and pneumonic lungs from all 4 herds. The prevalence was far higher in pneumonic (98 %) than in normal ones (28 %). Bacteria, mostly Pasteurella haemolytica, were also found in both pneumonic (49 %) and normal (18 %) lungs from all 4 herds. These results confirm the conclusions of a previous study that M. ovipneumoniae is of etiological significance in subacute or chronic pneumonia, whereas bacteria mainly occur as secondary invaders. M. ovipneumoniae appears, however, only to be a potential pathogen. Examinations for Mycoplasma arginini and virus were negative and these agents are considered to be of less significance in subacute or chronic pneumonia under Norwegian conditions.     

A new gene required for cellulose production and a gene encoding cellulolytic activity in Acetobacter xylinum are colocalized with the bcs operon.

Recently, it was shown that a cellulose-negative mutant (Cel1) of Acetobacter xylinum ATCC 23769 carried an insertion of an indigenous transposable element (IS1031A) about 500 bp upstream of the bcs operon, required for cellulose synthesis. Here we show that Cel1 can be complemented by wild-type DNA covering the insertion point. Nucleotide sequencing of this region revealed the presence of two open reading frames, ORF1 and ORF2. ORF2, which is disrupted by the IS1031A insertion in Cel1, potentially encodes the complementing function. ORF1 encodes a protein (CMCax) with significant homology to previously described endoglucanases. A cloned DNA fragment containing ORF1 expressed a carboxymethyl cellulose-hydrolyzing activity in Escherichia coli. In A. xylinum, CMCax is secreted into the culture growth medium. The CMCax mature protein consists of 322 amino acids and has a molecular mass of 35.6 kDa.     

Absence of relation between sick leave caused by musculoskeletal disorders and exposure to magnetic fields in an aluminum plant

This is a study of the relationship between occupational exposure to magnetic fields in pot rooms and occurrence of sick leave caused by musculoskeletal disorders. The average exposure to static magnetic fields was 8 mT in the pot rooms. Ripple fields were recorded as well. A cohort of 342 exposed workers and 222 unexposed workers from the same electrolysis plant was retrospectively followed for 5 years. The reference group had a type of work similar to the exposed group except for the exposure to magnetic fields. The occurrence of sick leave and the diagnoses causing the sick leave were obtained from the Occupational Health Care Unit: these data were stored in their computer files. The data were complete. No relationship between the occurrence of sick leave caused by musculoskeletal disorders and exposure to magnetic fields was found. This was the case for both the annual number of periods of sick leave and the total number of days with sick leave. The results must be interpreted with caution due to limitations in the design and available data. Also, static magnetic fields constituted the major exposure, and the results may be different when related to work in other types of magnetic-field exposure. © 1996 Wiley-Liss, Inc.     

Perturbations of plant leaflet rhythms caused by electromagnetic radio-frequency radiation

The minute-range up and down rhythms of the lateral leaflets of Desmodium gyrans has been studied when exposed to electromagnetic radiation in the radio-frequency (RF) range. The RF radiation was applied as homogeneous 27.12 MHz fields in specially-designed exposure cells(and in some cases as non-homogeneous radiation of 27 MHz. amplitude modulated by 50 Hz, in front of commercial diathermy equipment). All fields were applied as pulses. We report effects in the leaflet rhythms such as temporary changes in the amplitude, period, and phase. The radiation could also cause temporary or complete cessations of the rhythms. The lowest dose (8 W/cm²) used was still effective. © 1993 Wiley-Liss. Inc.     

Cleavage of cellulose by a CBM33 protein

Bacterial proteins categorized as family 33 carbohydrate-binding modules (CBM33) were recently shown to cleave crystalline chitin, using a mechanism that involves hydrolysis and oxidation. We show here that some members of the CBM33 family cleave crystalline cellulose as demonstrated by chromatographic and mass spectrometric analyses of soluble products released from Avicel or filter paper on incubation with CelS2, a CBM33-containing protein from Streptomyces coelicolor A3(2). These enzymes act synergistically with cellulases and may thus become important tools for efficient conversion of lignocellulosic biomass. Fungal proteins classified as glycoside hydrolase family 61 that are known to act synergistically with cellulases are likely to use a similar mechanism.     

Modulation of activity in human visual area V1 during memory masking

Neurons in the primary visual cortex, V1, are specialized for the processing of elemental features of the visual stimulus, such as orientation and spatial frequency. Recent fMRI evidence suggest that V1 neurons are also recruited in visual perceptual memory; a number of studies using multi-voxel pattern analysis have successfully decoded stimulus-specific information from V1 activity patterns during the delay phase in memory tasks. However, consistent fMRI signal modulations reflecting the memory process have not yet been demonstrated. Here, we report evidence, from three subjects, that the low V1 BOLD activity during retention of low-level visual features is caused by competing interactions between neural populations coding for different values along the spectrum of the dimension remembered. We applied a memory masking paradigm in which the memory representation of a masker stimulus interferes with a delayed spatial frequency discrimination task when its frequency differs from the discriminanda with ±1 octave and found that impaired behavioral performance due to masking is reflected in weaker V1 BOLD signals. This cross-channel inhibition in V1 only occurs with retinotopic overlap between the masker and the sample stimulus of the discrimination task. The results suggest that memory for spatial frequency is a local process in the retinotopically organized visual cortex.