An evaluation of fresh gas flow rates for spontaneously breathing cats and small dogs on the Humphrey ADE semi‐closed breathing system

ObjectiveTo evaluate the fresh gas flow (FGF) rate requirements for the Humphrey ADE semi-closed breathing system in the Mapleson A mode; to determine the FGF at which rebreathing occurs, and compare the efficiency of this system to the Bain (Mapleson D) system in spontaneously breathing cats and small dogs.Study DesignProspective clinical study.AnimalsTwenty-five healthy (ASA score I or II) client-owned cats and dogs (mean ± SD age 4.7 ± 5.0 years, and body weight 5.64 ± 3.26 kg) undergoing elective surgery or minor procedures.MethodsAnaesthesia was maintained with isoflurane delivered via the Humphrey ADE system in the A mode using an oxygen FGF of 100 mL kg⁻¹ minute⁻¹. The FGF was then reduced incrementally by 5–10 mL kg⁻¹minute⁻¹ at approximately five-minute intervals, until rebreathing (inspired CO₂ >5 mmHg (0.7 kPa)) was observed, after which flow rates were increased. In six animals, once the minimum FGF at which rebreathing occurred was found, the breathing system was changed to the Bain, and the effects of this FGF delivery examined, before FGF was increased.ResultsRebreathing did not occur at the FGF recommended by the manufacturer for the ADE. The mean ± SD FGF that resulted in rebreathing was 60 ± 20 mL kg⁻¹minute⁻¹. The mean minimum FGF at which rebreathing did not occur with the ADE was 87 ± 39 mL kg⁻¹minute⁻¹. This FGF resulted in significant rebreathing (inspired CO₂ 8.8 ± 2.6 mmHg (1.2 ± 0.3 kPa)) on the Bain system.ConclusionsThe FGF rates recommended for the Humphrey ADE are adequate to prevent rebreathing in spontaneously breathing cats and dogs <15 kg.Clinical relevanceThe Humphrey ADE system used in the A mode is a more efficient alternative to the Bain system, for maintenance of gaseous anaesthesia in spontaneously breathing cats and small dogs.     

A rapid method for early generation selection of dwarf genotypes in wheat

Summary In the early generations of a breeding programme to incorporate the successful Norin 10 semidwarfing genes into adapted tall or standard lines, the bread and durum wheat breeder must be able to recognise and discard those lines that are not homozygous for the dwarfing gene. A method which exploits the gibberellin insensitive reaction of lines carrying the genes combined with a single seed descent technique is described in which most unwanted genotypes may be removed as F2 seedlings.     

A novel enzyme-linked immunosorbent assay for the detection of Wx-B1 null wheat lines using a monoclonal antibody and its application for the detection of marker heterogeneity within commercial cultivars

A monoclonal antibody was raised with specificity for the granule bound starch synthase (GBSS1) Wx-B1 homeoallele of wheat (Triticum aestivum L.) using a synthetic peptide immunogen. This was used to develop a simplified enzyme-linked immunosorbent assay (ELISA) for the discrimination of Wx-B1a and Wx-B1b alleles which differ in the starch properties they confer. Discrimination of these alleles is important for the selection of wheat lines for Udon-style noodle production. The simplified ELISA worked in a single antibody (indirect) format and gave improved ease of use, discrimination of alleles and resolution relative to a previously developed 2-antibody (sandwich) ELISA. When the test was validated using breeders seed of a panel of commercial cultivars, heterogeneity of Wx-B1 alleles was observed for a significant proportion of the cultivars tested and this was confirmed using PCR analysis of the Wx-B1 and Wx-A1 genes. This observation has implications for cultivar wheat quality assessment, the application of molecular markers for variety identification purposes and the establishment of mapping populations from commercial cultivars.     

NORIN 10 semi-dwarfism in tetraploid wheat and associated effects on yield

Summary A genetic study of a range of NORIN 10 based semi-dwarf durum wheats showed that only Gai/Rht 1, located on chromosome 4A, was present. No varieties carrying a second Gai/Rht allele were identified and deliberate attempts to introduce Gai/Rht2 into tetraploid wheats have so far been unsuccessful.In a spaced plant trial of homozygous random F₃ lines from two tall x semi-dwarf crosses, the semi-dwarfs has lower ear yields, due mainly to reduced kernel weight, but had higher tiller numbers than the tall genotypes. Although there was no difference in overall plant yield between talls and semi-dwarfs, an analysis of character associations within the semi-dwarf F₃'s showed positive height-yield and height-kernel weight correlations indicating that selection for tall dwarfs may be a useful breeding strategy in tetraploid wheats.     

Conservation of marker synteny during evolution

Summary An aspect of cereal science that is becoming increasingly important is comparative genetics. Establishment of the relationship between genomes within polyploids, between species within tribes and between species within families will allow not only the integration of genetic maps but also the knowledge acquired of each of the species. Using a set of homoeologous probes, workers found the relationship between the three wheat genomes to be precisely collinear, after taking a few major translocation events into account. Transfer of the wheat map to rye led to the elucidation of similar relationships between the three wheat genomes and that of rye. Genome collinearity, however, extends even beyond tribes. In a comparison of the genomes of wheat, rice and maize, it was shown that despite the separation of these genomes for possibly 50 million years, gene order was still highly conserved. This collinearity between genomes can be exploited in a number of ways.     

Interaction ofErwinia spp. andFusarium roseum ‘Sambucinum’ on the Russet Burbank potato

Laboratory and field studies with the Russet Burbank (RB) potato provide evidence for synergism betweenErwinia carotovora var. atroseptica (Ea) andFusarium roseunt ‘Sambucinum’ (Fs). When these pathogens were inoculated together, the severity of tuber rot was significantly greater than when either pathogen was inoculated separately. Similarly, these pathogens interacted to reduce yield. When both organisms were uniformly applied to puncture wounds on potato seed (inoculum suspension consisted of 10⁸ cells/ml Ea and 10⁵ cells/ml Fs), the total yield was reduced by 46% and U.S. #1 yield by 53%. These reductions occurred even though blackleg symptoms (caused by Ea) were negligible (< 1%). In contrast, inoculations withErwinia carotovora var.carotovora (Ec) and Fs did not interact to reduce potato yield. Potato yields were also not influenced when these pathogens (Ea, Ec, Fs) were separately inoculated.Verticillium wilt (Verticillium dahliae) was significantly less when tubers were inoculated with either Ea, Ec, Fs, Ea + Fs, or Ec + Fs than with uninoculated tubers.     

Plastic films on plants as antitranspirants

Plastic-film-type antitranspirants are more permeable to water vapor than to carbon dioxide. Photosynthesis in treated plants is reduced to the same or greater extent than transpiration, except under conditions of stress, when photosynthesis in treated plants is greater than in controls. This exception is attributed to reduction of stress, as the selective permeability of the films to gases would tend to produce the reverse effect.