First Report of the A2 Mating Type of Phytophthora infestans on Tomato Crops in Taiwan, Republic of China.

In a study of the Phytophthora infestans population in Taiwan, samples with symptoms typical of late blight were collected from field crops in an important potato- (Solanum tuberosum) and tomato-(Lycopersicon esculentum) production area in the central highlands region. Isolates were obtained by surface disinfecting leaf sections and plating them onto antibiotic-amended rye A agar (1). After subculturing, the pathogen was confirmed as P. infestans on the basis of morphological characters (2). Mating type was determined by co-inoculating unamended rye agar plates with mycelial plugs of the test isolate and a reference P. infestans isolate of either the A1 or A2 mating type (four plates per test isolate, two with different A1, and two with different A2 reference isolates). After incubation (15°C darkness, 7 to 14 days), plates were examined microscopically for the presence of oospores where the colonies interacted. In 2004, one isolate of 200 tested, and in 2006, one isolate of 102 tested, produced oospores only with A1 reference isolates and were concluded to be A2 mating type. In vitro testing showed the two A2 isolates were metalaxyl-resistant (ED50 values >100 mg of metalaxyl per liter on rye grain agar), which is typical of recent P. infestans isolates from potato and tomato in this area (2). Twenty-one single-sporangial isolates from each of the two A2 strains were tested for mating type against two different A1 isolates of P. infestans and confirmed as A2. These isolates were characterized using the techniques described by Deahl et al. (1) and had the allozyme genotype 100/100/111, 100/100 at the loci coding for glucose-6-phosphate isomerase and peptidase, respectively, and were mitochondrial haplotype IIb. This multi-locus genotype is characteristic of recent P. infestans isolates from tomato and potato in Taiwan, but all previous such isolates were A1 mating type and attributed to the US-11 clonal lineage (1). When evaluated on differential hosts, both A2 isolates were tomato race PH-1 and complex potato race R 0,1,2,3,4,7,9,11. RG57 fingerprinting showed that the A2 isolates had fingerprints identical to each other and to A1 P. infestans isolates of the US-11 clonal lineage from tomato in Taiwan (101 011 100 100 110 101 011 001 1). Koch's postulates were completed and the two A2 isolates were found to be highly aggressive on cultivars of potato and tomato. To our knowledge, this is the first report of A2 mating type strains of P. infestans in the field in Taiwan, but currently, their incidence is very low (<1%). One crop from which an A2 isolate was obtained also yielded an A1 isolate, while A1 isolates were obtained from crops in the vicinity of the other. The concurrent presence of the two mating types of P. infestans poses a risk of sexual reproduction and oospore formation in tomato or potato in Taiwan. References: (1) K. L. Deahl et al. Pest Manag. Sci. 58:951, 2002. (2). D. C. Erwin and O. K. Ribeiro, Page 346 in: Phytophthora Diseases Worldwide. The American Phytopathological Society. St. Paul, MN, 1996.

Evaluation of Trichoderma spp. for biocontrol of tomato sudden caused by Pythium aphanidermatum following flooding in tropical hot season.

Tomato sudden death is a major problem in tomato production in tropical lowland areas. The plant wilts and dies following artificial or natural flooding for 48-72 hrs in the summer season. Occurrence of this disease is related to aggressiveness of Pythium aphanidermatum on tomato at high soil temperature (>30 degrees C). Several methods such as using biological control agents, fungicides and other cultural practices were applied in attempts to control tomato sudden death. Three Trichoderma harzianum and two Trichoderma virens isolates were evaluated for biocontrol of the disease in the greenhouse and in the field T. harzianum and T. virens isolates were separately used to treat the seed, potting medium and also incorporated into the soil before transplanting. Field soil was naturally infested with P. aphanidermatum, while greenhouse soil was inoculated with the pathogen 10 days after transplanting. All treatments were flooded for 48 hrs at 32 degrees C soil temperature. Results from this study show that most tested T. harzianum and T. virens isolates have little promise for control of tomato sudden death following flooding. The percentage of tomato plants that wilted after growing in soil treated with either T. harzianum or T. virens and P. aphanidermatum was not significantly different when compared to the soil treated with P. aphanidermatum alone. No wilted plants were observed in the control (non treated soil).

Molecular Characterization of Begomoviruses Associated with Leafcurl Diseases of Tomato in Bangladesh, Laos, Malaysia, Myanmar, and Vietnam.

Production of tomato (Lycopersicon esculentum) in Bangladesh, Malaysia, Myanmar, Vietnam, and Laos has been severely affected by yellow leaf curl disease. Tomato leaf samples were collected from symptomatic tomato plants from farmers' fields in the five countries from 1997 to 1999. DNA was extracted from all samples, four from Vietnam, two each from Malaysia, Laos, and Myanmar, and seven from Bangladesh. Virus DNA was amplified by polymerase chain reaction (PCR) using the begomovirus-specific degenerate primer pair PAL1v 1978/PAR1c 715(1), which amplifies the top part of DNA A. All samples gave the expected 1.4-kb PCR product. The PCR product of one sample per country was cloned and sequenced. Based on the sequences of the 1.4-kb DNA products amplified by the first primer pair, specific primers were designed to complete each of the DNA A sequences. Computer-assisted sequence comparisons were performed with begomovirus sequences available in the laboratory at the Asian Vegetable Research and Development Center, Shanhua, Tainan, and in the GenBank sequence database. The five DNA species resembled DNA A of begomoviruses. For the detection of DNA B two degenerate primer pairs were used, DNABLC1/DNABLV2 and DNABLC2/DNABLV2 (DNABLC1: 5'-GTVAATGGRGTDCACTTCTG-3', DNABLC2: 5'-RGTDCACTT CTGYARGATGC-3', DNABLV2: 5'-GAGTAGTAGTGBAKGTTGCA-3'), which were specifically designed to amplify DNA B of Asian tomato geminiviruses. Only the virus associated with yellow leaf curl of tomato in Bangladesh was found to contain a DNA B component, which was detected with the DNABLC1/DNABLV2 primer pair. The DNA A sequence derived from the virus associated with tomato yellow leaf curl from Myanmar (GenBank Accession No. AF206674) showed highest sequence identity (94%) with tomato yellow leaf curl virus from Thailand (GenBank Accession No. X63015), suggesting that it is a closely related strain of this virus. The other four viruses were distinct begomoviruses, because their sequences shared less than 90% identity with known begomoviruses of tomato or other crops. The sequence derived from the virus associated with tomato yellow leaf curl from Vietnam (GenBank Accession No. AF264063) showed highest sequence identity (82%) with the virus associated with chili leaf curl from Malaysia (GenBank Accession No. AF414287), whereas the virus associated with yellow leaf curl symptoms in tomato in Bangladesh (GenBank Accession No. AF188481) had the highest sequence identity (88%) with a tobacco geminivirus from Yunnan, China (GenBank Accession No. AF240675). The sequence derived from the virus associated with tomato yellow leaf curl from Laos (GenBank Accession No. AF195782) had the highest sequence identity (88%) with the tomato begomovirus from Malaysia (GenBank Accession No. AF327436). This report provides further evidence of the great genetic diversity of tomato-infecting begomoviruses in Asia. Reference: M. R. Rojas et al. Plant Dis. 77:340, 1993.

A centralized system for monitoring clozapine use in British Columbia.

The Clozapine Resource Centre in British Columbia is a centralized information source for all physicians wishing to prescribe clozapine and also performs back-up hematological and compliance monitoring. Laboratories fax weekly hematology results to physicians and to the center. The center enters results in a national database and compiles twice-weekly noncompliance reports; physicians are notified of abnormal results, and caregivers of noncompliance. The centralized system obviates the practice in some jurisdictions of hiring case coordinators to oversee these procedures and may reduce physician reluctance to prescribe clozapine. It improves coordination among monitoring and treatment parties and ensures better continuity of care.

Partial purification of proteinase inhibitors from wounded tomato plants.

Proteinase inhibitors were extracted from the upper leaves of tomato plants, Lycopersicon esculentum Mill., 48 hours after wounding single lower leaves. Inhibitors were partially purified by affinity chromatography and isoelectric focusing. Significantly higher levels of trypsin and chymotrypsin inhibitory activity were recovered from wounded plants than from unwounded controls. Several inhibitor peaks were partially resolved by isoelectric focusing of affinity column eluates from both wounded and control plants. Inhibitor activity associated with each peak was greater in wounded plants than in corresponding peaks of controls. Agar double diffusion immunological assays showed that inhibitors with basic isoelectric points (pI) of 9.5, 8.9, 8.3, 8.2, and 8.0 are serologically related to inhibitor I. Certain of these inhibitors (pI = 9.5, 8.2, and 8.0) reacted strongly with both inhibitors I and II antiserum. Three acidic proteinase inhibitors (pI = 6.5, 5.9, and 4.7), which accumulated due to wounding, also were isolated. These inhibitors are novel, since they were shown to be serologically unrelated to inhibitors I and II.

Solitary pulmonary nodules due to sarcoidosis.

Two patients, a 67-year-old woman and a 33-year-old man, had asymptomatic solitary nodular masses in the lung detected by roentgenographic examination. The preoperative investigations failed to make a firm diagnosis or to rule out the presence of a malignant lesion. In both patients the lesions were resected and found to contain noncaseating granulomas. Electron microscopy and immunochemical studies for lysozyme supported the diagnosis of solitary nodular sarcoidosis. Such roentgenographic presentations of sarcoid are rare.

Influence of alternate sources of bllod flow on the reactive hyperemia response in aorta-coronary saphenous vein bypass grafts in man.

Reactive hyperemia responses (RHR) of various magnitudes were obtained after release of a brief occlusion in six of 10 coronary bypass grafts. All of the vein grafts responded to an injection of sodium nitroprusside (50 microgram) directly into the open graft with an increase in blood flow that was always greater than the flow recorded after release of the occlusion. This response indicates that there were no flow-limiting stenoses and that the distal vascular beds were responsive to vasodilator stimuli. RHR's, expressed as percent repayment of calculated flow debt, were correlated significantly (r = 0.96, p less than 0.01) with the magnitude of the decrease in vein graft pressure measured during occlusion of the graft. It is suggested that the decrease in pressure is related to the amount of blood flow from alternate sources to the vascular bed during occlusion of the graft, and that this collateral flow is an important determinant of the magnitude of RHR in bypass grafts.

Osmotic interaction of plasma proteins with interstitial macromolecules.

The osmotic interaction of plasma proteins with collagen and hyaluronate has been evaluated by measuring the oncotic pressure of mixed solutions of varying composition. Collagen, despite its insolubility, exhibits a pronounced volume exclusion effect on plasma proteins, and the oncotic pressure of mixed solutions is considerably higher than that of the plasma protein stock solution. The volume exclusion of collagen on small molecules such as sucrose is negligible. A solution composed of 1.6% plasma proteins, 20% collagen, and .4% hyaluronate in Ringer solution, approximating the composition of the interstitium, was found to yield higher oncotic pressures than those previously reported from the interstitium. The probable role of impurities and degradation in the isolation process is discussed. Results reported earlier from in vitro and in vivo studies indicated that tissue oncotic pressures are considerably higher than generally recognized and that tissue fluid is in probable osmotic equilibrium with lymph in skin and muscle.

Saphenous vein bypass grafting for coronary atherosclerosis: clinical experience.

Saphenous vein bypass grafting is a recent and important procedure in the management of atherosclerotic coronary artery disease. A review of the first 150 patients operated on to July 1971 at the Toronto General Hospital is presented. Many had multiple bypass grafts and some had additional procedures including internal mammary artery implantation, valve replacement and scar tissue resection. There were five operative deaths (3%) and an additional five hospital deaths; the majority were related to myocardial infarction.A clinical review of the results six months to three years after operation indicates marked improvement in over 80% of the survivors. Postoperative hemodynamic studies were performed in many. It is suggested that patients with poor myocardial function presenting in failure may not benefit from the operation.