Biological effects and metabolism of fenoxycarb after treatment of the fourth and the fifth instars of the tobacco budworm,Heliothis virescens F.

Treatment of 4th and 5th instar larvae of Heliothis virescens with different amounts of fenoxycarb induced an increase in weight of the 5th larval instar, prolongation of the 5th larval instar period, or the formation of dauer larvae. No effects were observed during the 4th instar and the moult to the 5th larval instar. To check whether these effects were due to persistence of fenoxycarb in treated larvae, metabolism of this chemical was analysed. Larvae were fed with radio-labelled fenoxycarb at the first day of the 4th or at the first day of the 5th larval instar. Behaviour of the radio-labelled compounds was followed during each instar. At the time of gut purge, the whole of the radio-labelled material was excreted. The effects observed during the 5th instar of 4th-instar-treated larvae do not appear to be due to the persistence of fenoxycarb. The main metabolites of fenoxycarb were identified using coupled gas chromatography and mass spectrometry.     

Tests to determine LC50 and discriminating doses for macrocyclic lactones against the cattle tick, Boophilus microplus

Laboratory tests were carried out on larvae and adults of the cattle tick Boophilus microplus to determine the toxicity of macrocyclic lactone acaricides (MLs). Technical and commercial MLs were used in larval packet test (LPT), larval immersion test (LIT) and adult immersion test (AIT). In LIT and AIT the toxicity of MLs was much higher than for LPT. In the AIT, diluting the injectable formulation of MLs in water was as effective as dilution in ethanol+Triton X-100. LC50, LC99.9 and 95% confidence limits were determined so that a discriminating dose (DD) could be set for larval and adult tests in order to diagnose potential resistance to MLs in field samples of the tick. These DDs are for Australian strains of B. microplus and may not be suitable for other strains until further work is carried out.The value of these diagnostic tests can only be verified if or when resistance to MLs emerges in ticks.     

Interaction of benzimidazole-N-sulfonamides with the cytochrome b/c1 complex of Pythium aphanidermatum

Experiments with intact cells and submitochondrial fractions of Pythium aphanidermatum (Edson) Fitz. indicated an interference of benzimidazole-N-sulfonamides with the NADH- or succinate-driven electron transport system between cytochromes b and c. Comparison with Ustilago maydis (DC) Corda and Botrytis cinerea Pers. ex Fr. revealed that this effect is Oomycetes specific. The molecular interaction between benzimidazole-N-sulfonamides and the mitochondrial cytochrome b/c₁ complex from P. aphanidermatum has been investigated. Binding assays with [¹⁴C]52232 RP (dimefluazole) indicated a time- and dose-dependent labelling of two proteins. The molecular mass of one labelled protein and the competition of the binding with antimycin A suggest that benzimidazole-N-sulfonamides interact with the Q₁-centre of cytochrome b. Furthermore, experiments with doubly labelled [³H][¹⁴C]CGA 323103 revealed a possible irreversible inactivation of the b/c₁ complex leading to covalent linkage of the dimethylsulfonamoyl moiety to the target site.     

Oils for weed control: Uses and mode of action

The role of oils in herbicide treatments is reviewed, both in terms of their own intrinsic activity and of their enhancement of the performance of other herbicides. The phytotoxicity of oils can be related to their physical properties. Their efficacy as adjuvants can vary with the plant/pesticide combination involved, and differences may also be observed between oils of mineral and vegetable origin. The possible mechanisms involved in the enhancement of activity by oils are discussed and areas of work that might elucidate these fun her are indicated.     

A retrospective study of 30 cases of frozen lamellar corneal graft in dogs and cats

Frozen lamellar corneal grafts and nictitating membrane flaps were used in 18 dogs and 12 cats to repair deep corneal defects. In all dogs either melting corneal ulcers or descemetoceles were present. In the 12 cats, nine had either a melting corneal ulcer or descemetocele, two animals had acute bullous keratopathy, and one cat had corneal sequestrum. Initial vascularization with gradual clearing of the graft occurred during the first 45 days postoperatively. At 60 days postoperatively, all eyes were visual. Frequent postoperative complications included: focal dehiscence of the wound ( n  = 9); melting of part of the graft ( n  = 7); and pigmentation of the graft ( n  = 4). The frozen lamellar corneal graft was a very safe technique, and restored the tectonic and the optical function of the cornea. It provided the best results in corneas with nonperforating corneal defects. This technique provides poorer results when the cornea was perforated prior to surgery or during the surgical procedure.     

Historical evidence of an unusual deformity in dogs ("short-spine dog")

Abstract— —The author describes two malformed dogs portrayed in 1668 and 1690 by the court painter David Klocker Ehrenstrahl, who described the dogs as “monster of wolf and dog” and “monster of fox and dog” respectively. As the pictures were executed from living models and as the artist was known for his closeness to nature in his animal paintings, the author considers that the pictures can serve as the basis for a critical interpretation from the patho-anatomical viewpoint. The author shows how the paintings agree in every detail with the type of malformation in the Japanese breed of dog, described in 1956 as “short-spine dog”. The pictures can therefore be considered early historical evidence of the existence of this malformation. Résumé— —L'auteur décrit les chiens malformés figurant dans les deux portraits canins erécutés en 1668 et en 1690 par David Klöker Ehrenstrahl, peintré attitré de la cour de Suède, qui définit ses sujets comme “monstres”, hybrides “loup et chien” et “renard et chien”. Exécutés d'après nature, par un artiste réputé pour le réalisme de ses peintures d'animaux, les deux tableaux autorisent, de l'avis de l'auteur, une interprétation critique du point de vue pathologique et anatomique. L'auteur établit que les deux peintures représentent, avec une parfaite précision, les caractéristiques d'une malformation propre au chien indigène du Japon, phénoméne décrit en 1956 sous le nom de “chien à la colonne vertébrale raccourcie”. Les deux tableaux étudiés apportent donc une preuve de l'existence de cette malformation dès le XVIIe siècle. Zusammenfaeeung—Der Autor beschreibt zwei missgebildete Hunde, die 1668 und 1690 von dem Hofmaler David Klöcker Ehrenstrahl porträtiert wurden, welcher die Hunde als “Monstrum von Wolf und Hund” und “Monstrum von Fuchs und Hund” beschrieb. Da die Gemälde nach den lebenden Modellen ausgeführt wurden und der Künstler fiir seine Naturtreue in seinen Tierbildern bekannt war, Mält es der Autor für möglich, die Bilder als Grundlage einer kritischen Betrachtung vom pathologisch-anatomichen Standpunkt zu wählen. Der Autor zeigt, wie die Bilder in jeder Emzelheit mit der Art von Missbildung der in Japan einheimischen Hunderasse übereinstimmen, die 1956 als “Short-spine dog” beschrieben wurde. Die Bilder können deshalb als früher historischer Beweis für die Existenz dieser Missbildung angesehen werden.     

Severity of E. coli mastitis is mainly determined by cow factors

Intramammary infections of dairy cows with Gram-positive bacteria such as Staphylococcus aureus (major cause of mastitis) have received a lot of attention because of their major economic impact on the dairy farm through production losses induced by an increase in somatic cell count. Management strategies, including greater awareness for efficient milking and hygienic measures, have limited the spread of Gram-positive bacteria and resulted in a significant decrease of proportion of S. aureus isolates and subclinical mastitis worldwide. Other organisms such as coliform subspecies and Streptococcus uberis, both environmental bacteria that cause clinical mastitis, have received less attention. Escherichia coli causes inflammation of the mammary gland in dairy cows around parturition and during early lactation with striking local and sometimes severe systemic clinical symptoms. This disease affects many high producing cows in dairy herds and may cause several cases of death per year in the most severe cases. It is well known that bacterial, cow and environmental factors are interdependent and influence mastitis susceptibility. Many studies, executed during the last decade, indicate that the severity of E. coli mastitis is mainly determined by cow factors rather than by E. coli pathogenicity. During E. coli mastitis, the host defense status is a cardinal factor determining the outcome of the disease. Today, we know that the neutrophil is a key factor in the cows' defense against intramammary infection with E. coli. Effective elimination of the pathogen by neutrophils is important for the resolution of infection and the outcome of E. coli mastitis. This review is a compilation of some major findings over the last 15 years concerning mainly host factors that modulate and influence neutrophil function and the mammary inflammatory reaction. The individual chapters address: virulence factors of E. coli strains, how neutrophils kill E. coli, connection between endotoxins, tumor necrosis factor-alpha and nitric oxide, severity classification of E. coli mastitis, lifespan of neutrophils, host factors that influence severity, tissue damage and production loss.