Inhibitory Effects of Chinese Medicinal Herbs on Plant-Pathogenic Bacteria and Identification of the Active Components from Gallnuts of Chinese Sumac.

The aqueous extracts of 30 out of 67 Chinese medicinal herbs were shown to have inhibitory effects on growth of Xanthomonas euvesicatoria by a paper disc diffusion assay. The inhibitory substances with the strongest antibacterial activity were extracted from Chinese sumac gallnut and black myrobalan. The aqueous extract of gallnut inhibited the growth of eight of the tested plant-pathogenic bacteria, and that of black myrobalan inhibited five. The gallnut extract produced at least an 8-mm inhibition zone against Acidovorax citrulli, Ralstonia solanacearum, X. citri pv. citri, and X. euvesicatoria at a 10-fold dilution, and it was still active at 800- to 1,600-fold dilutions. The aqueous extract of gallnut was more inhibitory than the acetone-water extract. To identify the inhibitory compounds in the gallnut aqueous extract, the crude extract was chromatographed over a silica column, and the primary compounds in fractions 3 and 8 were identified by nuclear magnetic resonance as gallic acid and methyl gallate, respectively. The inhibitory effect of methyl gallate on the growth of four plant-pathogenic bacteria was 10 to 80 times that of gallic acid. The minimum inhibition and minimum bactericidal concentration tests showed that the inhibition effect of the original aqueous was higher than that of methyl gallate. These results indicate that methyl gallate in gallnut is an important compound that is inhibitory to plant-pathogenic bacterial growth, and there are other unidentified compounds that are also responsible for the antibacterial effects. This is the first report regarding the antibacterial effects of gallnut extract and its chemical components on plant-pathogenic bacteria.

First Report of Leaf Blight on Calathea picturata Caused by Exserohilum rostratum in Taiwan.

Many Calathea species in the family Marantaceae are beautiful ornamental plants with variegated foliage. Among them, C. picturata 'Argentea', an evergreen perennial that has pale green leaves with dark green margins and a red underside, is a popular houseplant in Taiwan. In 2004, a new foliage disease that caused leaf blight of C. picturata 'Argentea' was first observed in a nursery in southern Taiwan. Initial symptoms were tiny, brown spots that appeared on the leaves of all ages, which quickly enlarged and coalesced. These necrotic lesions spread to cover the entire leaves in high temperature and moisture conditions and caused leaves to shrivel and eventually die. A dematiaceous hyphomycete with multicelled conidia was consistently isolated from the diseased leaves after being surfaced sterilized with 10% Clorox and placed on vegetable juice agar (10% V8 juice, 0.02% CaCO3, and 2% agar [VJA]). Pathogenicity of the isolate was tested by spraying 'Argentea' calathea leaves with a conidia suspension (1.6 × 105 conidia/ml) prepared from a culture grown on VJA at 28°C for 7 days. Plant leaves sprayed with distilled water were used as a control. Three pots of 15-cm high 'Argentea' calathea plants were inoculated with 10 ml of a conidia suspension and the experiment was conducted twice at 28°C and 90% relative humidity in a growth chamber. Tiny, brown spots started to show on all inoculated leaves 5 days after inoculation and the progression of symptom development was similar to that observed in nature. Control leaves remained asymptomatic. The same dematiaceous hyphomycete fungus was reisolated from 13 of 16 disease tissues taken from four symptomatic leaves. A colony of the calathea isolate was olive green when grown on potato dextrose agar (PDA) and conidia production was observed 7 days after incubation in darkness. The conidiophores were either branches from or the ends of normal mycelium, some of them geniculate with conidium produced at each bend measuring 142 to 602 (340) × 3 to 6 (4) µm on disease tissues and 51 to 150 (103) × 3 to 5 (4) µm on PDA. Conidia were multicelled with protruding hilum at the base, terminal cells thickened, olivaceous brown or golden brown in fusiform shape with blunt tips, 5 to 11 septate on disease tissues and 6 to 11 septate on PDA, measuring 46 to 166 (95) × 8 to 19 (13) µm on disease tissues and 58 to 145 (94) × 6 to 15 (11) µm on PDA, germinating by producing germ tubes semiaxially from each end. Morphological characteristics of the calathea isolate fit the description of the genus Exserohilum (2). Comparison of rDNA internal transcribed spacer (ITS) sequence of the calathea isolate with those in GenBank revealed that it shared 99.5% (549 of 552) similarity with a published sequence (GenBank Accession No. EU571210) (3) and Exserohilum rostratum was its closest species. ITS sequence analysis was done as previously described (1). Morphological and molecular data identified the pathogen as E. rostratum (Drechs.) Leonard & Suggs (= Bipolaris rostrata (Drechs.) Shoemaker). To our knowledge, this is the first report of leaf blight caused by E. rostratum on C. picturata in Taiwan. References: (1) L. L. Chern et al. Plant Dis. 94:1164, 2010. (2) K. J. Leonard. Mycologia 68:402, 1976. (3) R. Sappapan et al. J. Nat. Prod. 71:1657, 2008.

First Report of Root and Basal Rot of Angelica acutiloba Caused by Fusarium solani in Taiwan.

Angelica (Angelica acutiloba (Siebold. & Zucc.) Kitag.) is one of the most important traditional Chinese medicines in Taiwan. The medicinal herb has been mainly imported from China, but cultivation at a commercial scale has also been established in recent years in Hualien County, Taiwan. In September 2008, angelica plants in a field at Liou-shih-dan Mountain displayed symptoms of yellowing, stunting, rotting of roots and basal stem, and wilting. A severe brown discoloration of vascular tissue along the stems of infected plants was observed. One or more Fusarium spp. was consistently isolated from the roots and stems of diseased plants. Isolates R3, R4, and R5 were incubated for 14 days on celery tissues to produce chlamydospores, and 33 g of celery tissue with chlamydospores were mixed with 500 ml of soil per pot as inoculum. One 4-month-old angelica seedling was planted per pot. Three angelica plants were inoculated with each isolate in the first test and nine plants were inoculated with each isolate in the second test. Other seedlings were inoculated with water as checks. Pathogenicity tests were conducted twice. Incidence of diseased plants was 66, 100, and 33% in the first test, and 66, 100, and 44% in the second test for the R3, R4, and R5 isolates, respectively. Symptoms similar to those on the diseased plants in the field were produced, with leaves turning yellow starting 7 days after inoculation and wilt and discoloration of roots 14 days after inoculation. Fusarium spp. also were reisolated from the diseased plants. Genomic DNA was extracted from mycelium with a fungal genomic DNA purification kit, and the internal transcribed spacer (ITS) rDNA region was amplified and sequenced with primers ITS-4 and ITS-5. The sequence of the resulting ~550-bp amplicon was compared with those in GenBank. The ITS sequences of the R3, R4, and R5 isolates shared 98.7, 98.7, and 97.9% similarity with F. solani isolate AF129104 (3), respectively. Phylogenetic analysis also showed that the three isolates were closer to F. solani than to other Fusarium species. Both macroconidia and microconidia of the R4 isolate were produced on potato dextrose agar. Macroconidia were three to five septate and 27.2 to 37.8 × 4.4 to 6.2 µm; microconidia were zero to one septate and 9.3 to 14.7 × 2.9 to 4.8 µm. Chlamydospores produced on celery juice agar were terminal or intercalary, solitary, in pairs or in chains, and 9.3 to 12.1 µm. Morphological characteristics identified the three isolates as F. solani (Martius) Snyder & Hansen according to Fu and Chang (2) and Chung et al. (1), which agrees with the ITS comparison. To our knowledge, this is the first report of root and basal rot caused by F. solani on angelica in Taiwan. References: (1) W. C. Chung et al. Plant Prot. Bull. 40:177, 1998. (2) C. H. Fu and T. T. Chang. Taiwan J. For. Sci. 14:223, 1999. (3) H. Suga et al. Mycol. Res. 104:1175, 2000.

Polycystic kidney disease is a risk factor for new-onset diabetes after transplantation.

BACKGROUND: Data from matched historical cohort studies suggest that autosomal-dominant polycystic kidney disease (ADPKD) may be a risk factor for new-onset diabetes after transplantation (NODAT). METHOD: A retrospective study of 429 renal allografts transplanted from 1990 through 2004 in nondiabetic patients was performed. A multivariate analysis of risk factors for NODAT was performed with focus on ADPKD. RESULTS: A total of 6.5% of all patients developed NODAT and a further 11% developed impaired glucose tolerance. NODAT developed in 13.4% of patients with ADPKD compared with 5.2% of non-ADPKD patients (P=0.01). There were significant univariate associations between NODAT and recipient age (P=0.001) and weight (P<0.0001). There was no association between NODAT and recipient gender, human leukocyte antigen mismatch, acute rejection, or cumulative methylprednisolone dose. In a multivariate analysis, ADPKD was a strong risk factor for the development of NODAT (odds ratio [OR]=2.41, P=0.035) after correction for recipient age, weight, gender, ethnicity, and tacrolimus use. Age (OR=1.06), weight (OR=1.04), and nonwhite race (OR=5.04) were the other significant variables. CONCLUSION: We conclude that ADPKD is a significant risk factor for the development of NODAT. This may influence the follow up and management choices of these patients in the future.

Alterations in the conjunctival bacterial flora following a single dose of azithromycin in a trachoma endemic area.

BACKGROUND/AIMS: The World Health Organisation has recommended repeated mass treatment of children in trachoma endemic areas with oral azithromycin. While chlamydia, the causative agent of trachoma, remains universally sensitive to azithromycin, there is concern that large scale programmes may alter the bacterial flora and induce resistance in streptococcal species. In this study the effect of a single dose of azithromcyin on the prevalence, species distribution, and resistance of conjunctival bacterial flora was determined. METHODS: Baseline and 14 day follow up bacterial cultures were taken from the conjunctivae of 121 children who reside in a trachoma endemic area of Nepal. 91 children were treated with azithromycin at baseline and 31 children received deferred treatment at the 14 day follow up. RESULTS: Although the prevalence of bacterial pathogens decreased significantly with azithromycin treatment, a significant change in the distribution of specific bacterial pathogens could not be demonstrated. Streptococcal resistance to azithromycin was found significantly more frequently after treatment. No change in the prevalence, distribution, or resistance pattern was found in the untreated control group. CONCLUSION: Repeated mass treatment of trachoma endemic areas with oral azithromycin will have an effect on bacterial flora. However, further work needs to be done to determine if this will have any clinical relevance.

Root and Foot Rot of Loquat in Taiwan Caused by Phytophthora.

Loquat trees growing in central Taiwan were inflicted with a disease causing wilting and death of plants due to severe foot and root rot. The vascular tissues of all infected plants turned brown. Typical as well as atypical isolates of Phytophthora parasitica were isolated from the diseased basal stem and root tissues but not from the discolored vascular tissues. Symptoms observed in the field were reproduced when roots and stems of loquat seedlings were inoculated with zoospores of atypical isolates of P. parasitica; whereas only fibrous root rot resulted from inoculation with typical isolates of P. parasitica. Atypical isolates could be differentiated from the typical isolates of P. parasitica by several characteristics, including colony appearance, partial caducous sporangia, size of oospore, growth at 36°C, mycelial soluble protein patterns, and pathogenicity.

Cutaneous chylous reflux.

Two cases of cutaneous chylous reflux are described. Both patients had many translucent white vesicles from which milk-like fluid wept intermittently. Lymphangiogram revealed dilated, tortuous lymphatic vessels and dermal backflow. Electron microscopic studies showed an abnormal ultrastructure of the dilated lymphatics.