Use of electromyography for the diagnosis of equine hyperkalemic periodic paresis.

The use of electromyography (EMG) as a diagnostic aid for equine hyperkalemic periodic paresis (EHPP) was investigated in seven affected and seven control horses. Affected horses were confirmed positive for EHPP either by elevated serum potassium concentration with clinical signs of myotonia, or by inducing hyperkalemia and clinical signs using oral potassium chloride challenge. All horses were asymptomatic at the time EMG was performed, using bipolar fine wire needle electrodes. The myopotentials were recorded on magnetic tape and displayed on paper charts for analysis. Insertional and resting activity were recorded from the right supraspinatus, triceps, extensor carpi radialis and gluteal muscles in standing horses. Myotonic discharges were seen in six of seven affected horses but not in any of the controls. All seven affected horses and two control horses had prolonged insertional activity. Five out of seven affected horses and one control horse displayed spontaneous motor unit discharges unrelated to recording electrode movement. Myoelectrical potentials containing closely timed muscle potentials, i.e. doublets, were found in all affected horses, with four of seven affected horses also showing triplets. These potentials were not observed in any of the controls. No obvious difference in activity was observed among the four muscle sites tested. It is concluded that EMG is a safe and useful tool for diagnosing EHPP in horses not currently displaying clinical signs. Myotonic discharges and doublets appear to be the most diagnostically significant electromyographic abnormalities in EHPP affected horses.     

Comparison of mycoplasma ovipneumoniae isolates using bacterial restriction endonuclease DNA analysis and SDS-PAGE

Sixteen isolates of Mycoplasma ovipneumoniae recovered from the nasal tract or lungs of sheep from different flocks in New Zealand were examined by bacterial restriction endonuclease DNA analysis (BRENDA) using EcoR1 and by sodium dodecyl sulphate-polycrylamide gel electrophoresis (SDS-PAGE). All isolates gave BRENDA patterns which differed entirely from one another. Following 20 serial passages (corresponding to approximately 67 generations) of an isolate, no charge was detected in the BRENDA pattern.

When eight isolates were examined by SDS-PAGE most bands were common but, nevertheless, each isolate was unique in the sense that they differed from one another in one or more bands. The marked heterogeneity of patterns observed when strains of M. ovipneumoniae are compared by BRENDA, together with the stability of such patterns over many generations, will enable this approach to be used to study the epidemiology of individual strains of M. ovipneumoniae with a flock.     

Epidemiology of brown rot (Monilinia fructigena) on apple: infection of fruits by conidia

Effects of fruit maturity, wound age, temperature and the duration of wetness periods on infection of apple fruits by conidia of the brown rot fungus, Monilinia fructigena , were studied. Inoculation of fruits on potted apple trees and harvested mature fruits showed that wounding was essential for infection by M. fructigena . On potted trees, there was a significant difference between the susceptibility of cvs Cox and Gala and this difference depended on wound age. The incidence of brown rot was affected greatly by fruit maturity and wound age. Wounds on younger fruits were more resistant to infection than those on older fruits, whilst the older the wound, the more resistant it was to infection. Furthermore, the degree of wound age-related resistance was greater on younger fruits than on older fruits. These relationships were well described by regression models. The effect of the duration of wetness periods was very small: increasing the duration of wetness periods reduced the incidence of brown rot on older wounds. For detached fruits, all those wounded were rotted after inoculation, except for those in two treatments under 20°C on fruits with wounds which were 8 days old. The incubation period of the fungus was generally very short. Wound age was the single most important factor influencing the length of the incubation period; the incubation period increased as wound age increased.     

Effects of temperature on the incubation and latent periods of hawthorn powdery mildew (Podosphaera clandestina)

The effects of temperature on the length of the incubation and latent periods of hawthorn powdery mildew, caused by Podosphaera clandestina , were studied. At constant temperatures over the range 10–28°C, the incubation period ranged from 5 to 14 days and the latent period from 5 to 16 days; no visible colonies had developed at 30°C after 15 days. The relationships between temperature and the rates of fungus development within the incubation and latent periods were well described by a nonlinear model. The resulting curves were asymmetrically bell-shaped with an optimum temperature of approximately 23°C. The lengths of the incubation and latent periods under fluctuating temperatures were also determined, and were used to evaluate the models developed from constant temperature experiments for their accuracy of prediction. The incubation and latent periods under fluctuating temperature regimes were predicted using a rate-summation scheme with a time step of 24 min, by integrating the respective incubation and latent rate functions obtained under constant temperatures. The predicted incubation or latent periods agreed well with the observed values. Under constant temperature the interval between the times when symptoms and sporulation on the same leaflet were first observed was very short, on average <1 day, and was not significantly correlated with temperature. However, this interval was negatively correlated with mean temperature under fluctuating regimes.     

红莲型细胞质雄性不育恢复系特青和珍汕97的恢复性遗传分析

以花粉育性和小穗育性为指标 ,对红莲型细胞质雄性不育系丛广 4 1 A、恢复系特青以及丛广 4 1 A/特青的 F1 、F2 ,丛广 4 1 A∥丛广 4 1 B/特青的三交 F1 等亲本和杂种群体的育性调查分析结果表明 :特青具有 1个主效的显性恢复基因 ,该基因暂命名为 Rf-5(t) ;对红莲型细胞质雄性不育系丛广 4 1 A、恢复系珍汕 97以及丛广 4 1 A/珍汕 97的 F1 、F2 ,丛广 4 1 A∥丛广 4 1 B/珍汕 97的三交 F1 等亲本和杂种群体的育性调查分析结果表明 :在红莲型细胞质雄性不育和恢复性上 ,这 2个亲本之间可能有两类基因 ,其中一类控制着圆败型花粉 ,另一类控制着典败型花粉 ;对丛广 4 1 A∥珍汕 97/特青三交 F1 的育性调查分析结果表明 :珍汕 97具有一个与 Rf-5(t)等位的恢复基因     

Key biodiversity areas as globally significant target sites for the conservation of marine biological diversity

• 1. Recent approaches to the planning of marine protected area (MPA) networks for biodiversity conservation often stress the need for a representative coverage of habitat types while aiming to minimize impacts on resource users. As typified by planning for the Australian South‐east Marine Region, this strategy can be manipulated by political processes, with consequent biased siting of MPAs. Networks thus created frequently possess relatively low value for biodiversity conservation, despite significant costs in establishment and maintenance.
• 2. Such biases can be minimized through application of the data‐driven and species‐based concept of key biodiversity areas (KBAs).
• 3. By mapping locations of threatened species and populations that are highly aggregated in time or space, the KBA process allows marine sites of global biodiversity significance to be systematically identified as priority conservation targets. Here, the value of KBAs for marine conservation planning is outlined, and guidelines and provisional criteria for their application provided.

Copyright © 2008 John Wiley & Sons, Ltd.     

Mitigating fur seal interactions: relocation from Tasmanian aquaculture farms

• 1. At Tasmanian salmon aquaculture farms, fur seals were trapped and relocated to reduce interactions with stock, operations and equipment. From 1990 to 2005, 4517 relocations of 1124 seals were undertaken, peaking at 1203 relocations in 2003.
• 2. Of the relocations, 56% were recaptured seals. Most seals had less than 10 captures (46%), with 3% trapped more than 20 times.
• 3. Relocations were mostly seasonal, occurring in the austral winter and spring with a peak in August.
• 4. Seal recapture intervals were highly variable, ranging from days to years. Within the same year, recapture intervals per seal ranged from 4 to 258 days, mean 36 days.
• 5. Australian fur seals were trapped more frequently than New Zealand fur seals. The first trapped New Zealand fur seal was identified in 2000.
• 6. Relocation provides short‐term relief from seal interactions but does not mitigate the interaction problem in the longer term.
• 7. The core of the seal interaction problem is the current inability to exclude seals from pens and fish stock. Salmon farms are providing a predictable, accessible food source for seals.

Copyright © 2008 John Wiley & Sons, Ltd.     

Comparing multi- and single-scale species distribution and abundance models built with the boosted regression tree algorithm

Landscape Ecology - Species are influenced by factors operating at multiple scales, but multi-scale species distribution and abundance models are rarely used. Though multi-scale species...     

Visualization of root growth in heterogeneously contaminated soil using neutron radiography

We used neutron radiography (NR), a non-invasive and in situ technique, to study living plant roots in soil. Plant roots have a larger water content than their unsaturated surrounding media. As water strongly attenuates a neutron-beam, NR can identify root structures in detail. We investigated the use of NR to visualize the root growth of lupin in quartz sand and in a loamy sand field soil. Further experiments elucidated the root growth of lupin in the loamy sand heterogeneously contaminated with 10 and 20 mg kg⁻¹ boron (B) and 100 mg kg⁻¹ zinc (Zn). We obtained high-quality images of root growth dynamics in both media with a resolution range of 110–270 μm. The images with quartz sand revealed fine structures such as proteoid roots that are difficult to locate in situ by other methods without destruction of the soil. Though quartz sand provided excellent visibility of roots, it proved to be a poor medium for growing plants, probably because of its bulk density (1.8 Mg m⁻³). The images with field soil showed normal root growth with slightly less contrast than the quartz sand. The poorer contrast was due to the greater neutron interaction with soil water and soil organic matter. In the heterogeneously contaminated soil, root growth was significantly reduced in the contaminated part of the soil in all B and Zn treatments. This study shows that NR has potential as a non-invasive method to investigate root growth over time as well as the response of roots to various abiotic stress factors.     

Gibberellic Acid: effects of feeding in an artificial diet for honeybees

Complete larval and pupal development occur in colonies of honeybees when adult bees are allowed to feed upon an artificial diet containing gibberellic acid. In the absence of gibberellic acid larvae die in the 3rd or 4th day of development.