Management of downy mildew of sweet basil (Ocimum basilicum) caused by Peronospora belbahrii by means of resistance inducers, fungicides, biocontrol agents and natural products

To control downy mildew of sweet basil (Ocimum basilicum L.), incited by Peronospora belbahrii Thines, a number of compounds were tested in 2011 and 2012 under glasshouse conditions. These included copper-based fungicides, biocontrol agents, and compounds previously reported to induce resistance in plants to pathogens. Results were compared with those provided by fungicides registered for downy mildew control in Italy. The tested compounds were used alone or applied in rotation in spray programs. In all trials, the greatest reduction in disease incidence and severity was found with treatments that included metalaxyl-M?+?copper hydroxide, a mineral fertilizer ‘Alexin’, mandipropanid, and azoxystrobin. The glucohumates activator complex and acibenzolar-S-methyl also provided significant disease control (P?<?0.05). The mineral fertilizer Alexin, the glucohumates activator complex and acibenzolar-S significantly reduced disease incidence and severity 20 days after the last treatment compared with the untreated control (P?<?0.05). Among the copper-based products, the greatest reductions in disease incidence and severity were provided by copper hydroxide with terpenic alcohols and copper oxychloride?+?copper hydroxide. The mineral fertilizer Kendal and prohexadione-Ca, as well as mustard oil, partially reduced disease incidence and severity compared with the untreated control (P?<?0.05), whereas the biocontrol agent Bacillus subtilis QST 713 and thyme oil extract were not effective in two out of three trials. When different combinations of various products used in rotation were tested, effective control was found either using a rotation of fungicides with compounds that can induce resistance, as well as by using rotation with different resistance-inducing compounds on their own.     

Maxillary dentigerous cyst in a cat

A dentigerous cyst was diagnosed in the right rostral maxilla of a 6-month-old Siamese cat affecting the maxillary right canine tooth. The deciduous maxillary right canine tooth was extracted and the dentigerous cyst wall was curetted. The permanent tooth was not removed, however it was mobile following the surgical procedure. Examination 6-months following surgery indicated appropriate development of the tooth with no mobility or periodontal pocket formation. The maxillary right canine tooth had an abnormal shape but was functional with an acceptable appearance.     

Herbicide resistance in Aster squamatus conferred by a less sensitive form of acetolactate synthase

A biotype of Aster squamatus (Sprengel) Hieronymus with suspected resistance to the ALS-inhibiting herbicide imazapyr was detected in a chicken farm in the province of Seville, Spain, which had been treated once a year with imazapyr for 10 years. Resistance to imazapyr in this biotype was studied using dose-response experiments, absorption and translocation assays, metabolism studies and ALS activity assays. The rate of imazapyr required to inhibit A squamatus growth by 50% (ED50) was 15 times higher for the R (resistant) than for the S (susceptible) biotype. Cross-resistance existed for the ALS-inhibitors imazamox, imazethapyr, amidosulfuron, nicosulfuron, rimsulfuron, triasulfuron and tribenuron, but not for bensulfuron. Control of A squamatus using alternative herbicides was poor with clopyralid, intermediate with quinclorac, amitrole and MCPA, and excellent with 2,4-D, glufosinate and glyphosate. Absorption of [14C]imazapyr increased over time for both the R and S biotypes, and translocation from the treated leaf to shoots and roots was similar in both biotypes, with most of the radioactivity remaining in the treated leaf. No metabolites of imazapyr were detected in either biotype. Sensitivity of the ALS enzyme (target site) to imazapyr was lower for the R biotype (I50(R) = 4.28 x I50(S)). The mechanism of imazapyr resistance in this R biotype appears to be an altered ALS conferring decreased sensitivity to imazapyr at the whole-plant level.     

Evaluation of various compounds to inhibit activity of matrix metalloproteinases in the tear film of horses with ulcerative keratitis

OBJECTIVE: To examine in vitro effects of various antiproteolytic compounds on activity of matrix metalloproteinase (MMP)-2 and -9 in the tear film of horses with active corneal ulcers. SAMPLE POPULATION: Samples of tear film obtained from the eyes of 34 horses with active ulcerative keratitis. PROCEDURE: Horses were sedated, and tear samples were collected from the lower fornix of 34 ulcerated eyes by use of capillary tubes. The protease inhibitors 0.2% EDTA, 0.1% doxycycline, 10% N-acetylcysteine (NAC), 0.1% solution of a modified dipeptide that contains hydroxamic acid (ie, ilomostat), 0.1% alpha1-proteinase inhibitor (PI), 0.5% alpha1-PI, and 100% fresh equine serum (ES) were used to treat pooled samples. Amount of latent and active MMP-2 and -9 was measured by optical density scanning of gelatin zymograms of treated and untreated tear samples. RESULTS: Pooled tear samples obtained from ulcerated eyes contained the latent and active forms of MMP-2 and -9. Compared with MMP activity in untreated samples, total MMP activity (sum of all bands detected) observed on the gelatin zymogram gels was reduced by 99.4% by EDTA, 96.3% by doxycycline, 98.8% by NAC, 98.9% by ilomostat, 52.4% by 0.1% alpha1-PI, 93.6% by 0.5% alpha1-PI, and 90.0% by ES. CONCLUSIONS AND CLINICAL RELEVANCE: We documented that EDTA, doxycycline, NAC, ilomostat, alpha1PI, and ES inhibited MMP activity in vitro. Because these compounds use different mechanisms to inhibit various families of proteases in the tear film of horses, a combination of these protease inhibitors may be beneficial for treatment of corneal ulcers in horses.     

Agreement among surgical pathologists evaluating routine histologic sections of digits amputated from cats and dogs.

Agreement among pathologists interpreting histologic specimens is an area of interest within human pathology, but little work in this area has been reported in the veterinary literature. Agreement among pathologists evaluating routine histologic sections of amputated digits from cats and dogs submitted to multiple diagnostic centers was examined. Histologic sections from surgical specimens were reviewed in a blinded fashion by two pathologists, and a comparison to the original diagnosis, as stated in the diagnostic report, was recorded. A total of 513 cases were reviewed, and complete agreement was reached in 409 (79.7%). Of the 104 instances of disagreement, 77 (74.0%) were considered to be of clinical significance. The diagnosis of keratoacanthoma was disagreed with in 19 of 21 diagnoses (90.4%). No other individual diagnosis was similarly disputed. The overall level of disagreement is large and is similar to that reported in human pathology and suggests that further study of this issue would be useful in veterinary pathology.     

Usefulness of the murine model to study the immune response against Histoplasma capsulatum infection

The present paper is an overview of the primary events that are associated with the histoplasmosis immune response in the murine model. Valuable data that have been recorded in the scientific literature have contributed to an improved understanding of the clinical course of this systemic mycosis, which is caused by the dimorphic fungus Histoplasma capsulatum. Data must be analyzed carefully, given that misinterpretation could be generated because most of the available information is based on experimental host–parasite interactions that used inappropriate proceedings, i.e., the non-natural route of infection with the parasitic and virulent fungal yeast-phase, which is not the usual infective phase of the etiological agent of this mycosis.