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1.
BMC Med Educ ; 23(1): 457, 2023 Jun 20.
Article in English | MEDLINE | ID: mdl-37340427

ABSTRACT

OBJECTIVES: A partnership model in interprofessional education (IPE) is important in promoting a sense of global citizenship while preparing students for cross-sector problem-solving. However, the literature remains scant in providing useful guidance for the development of an IPE programme co-implemented by external partners. In this pioneering study, we describe the processes of forging global partnerships in co-implementing IPE and evaluate the programme in light of the preliminary data available. METHODS: This study is generally quantitative. We collected data from a total of 747 health and social care students from four higher education institutions. We utilized a descriptive narrative format and a quantitative design to present our experiences of running IPE with external partners and performed independent t-tests and analysis of variance to examine pretest and posttest mean differences in students' data. RESULTS: We identified factors in establishing a cross-institutional IPE programme. These factors include complementarity of expertise, mutual benefits, internet connectivity, interactivity of design, and time difference. We found significant pretest-posttest differences in students' readiness for interprofessional learning (teamwork and collaboration, positive professional identity, roles, and responsibilities). We also found a significant decrease in students' social interaction anxiety after the IPE simulation. CONCLUSIONS: The narrative of our experiences described in this manuscript could be considered by higher education institutions seeking to forge meaningful external partnerships in their effort to establish interprofessional global health education.


Subject(s)
Interprofessional Education , Students, Health Occupations , Humans , Learning , Problem Solving , Universities , Interprofessional Relations , Attitude of Health Personnel
2.
Hong Kong Med J ; 29(2): 105-111, 2023 04.
Article in English | MEDLINE | ID: mdl-36990676

ABSTRACT

INTRODUCTION: This study aims to determine the outcomes of stereotactic body radiotherapy (SBRT) for liver metastases in patients not eligible for surgery. METHODS: This study included 31 consecutive patients with unresectable liver metastases who received SBRT between January 2012 and December 2017; 22 patients had primary colorectal cancer and nine patients had primary non-colorectal cancer. Treatments ranged from 24 Gy to 48 Gy in 3 to 6 fractions over 1 to 2 weeks. Survival, response rates, toxicities, clinical characteristics, and dosimetric parameters were evaluated. Multivariate analysis was performed to identify significant prognostic factors for survival. RESULTS: Among these 31 patients, 65% had received at least one prior regimen of systemic therapy for metastatic disease, whereas 29% had received chemotherapy for disease progression or immediately after SBRT. The median follow-up interval was 18.9 months; actuarial in-field local control rates at 1, 2, and 3 years after SBRT were 94%, 55%, and 42%, respectively. The median survival duration was 32.9 months; 1-year, 2-year, and 3-year actuarial survival rates were 89.6%, 57.1%, and 46.2%, respectively. The median time to progression was 10.9 months. Stereotactic body radiotherapy was well-tolerated, with grade 1 toxicities of fatigue (19%) and nausea (10%). Patients who received post-SBRT chemotherapy had significant longer overall survival (P=0.039 for all patients and P=0.001 for patients with primary colorectal cancer). CONCLUSION: Stereotactic body radiotherapy can be safely administered to patients with unresectable liver metastases, and it may delay the need for chemotherapy. This treatment should be considered for selected patients with unresectable liver metastases.


Subject(s)
Liver Neoplasms , Radiosurgery , Humans , Radiosurgery/adverse effects , Prognosis , Liver Neoplasms/radiotherapy , Liver Neoplasms/pathology , Retrospective Studies
3.
Proc Biol Sci ; 285(1891)2018 11 21.
Article in English | MEDLINE | ID: mdl-30464062

ABSTRACT

In social groups, high reproductive skew is predicted to arise when the reproductive output of a group is limited, and dominant individuals can suppress subordinate reproductive efforts. Reproductive suppression is often assumed to occur via overt aggression or the threat of eviction. It is unclear, however, whether the threat of eviction alone is sufficient to induce reproductive restraint by subordinates. Here, we test two assumptions of the restraint model of reproductive skew by investigating whether resource limitation generates reproductive competition and whether the threat of eviction leads to reproductive restraint in the clown anemonefish Amphiprion percula First, we use a feeding experiment to test whether reproduction is resource limited, which would create an incentive for the dominant pair to suppress subordinate reproduction. We show that the number of eggs laid increased in the population over the study period, but the per cent increase in fed groups was more than twice that in unfed groups (205% and 78%, respectively). Second, we use an eviction experiment to test whether the dominant pair evicts mature subordinates, which would create an incentive for the subordinates to forgo reproduction. We show that mature subordinates are seven times more likely to be evicted than immature subordinates of the same size. In summary, we provide experimental support for the assumptions of the restraint model by showing that resource limitation creates reproductive competition and a credible threat of eviction helps explain why subordinates forego reproduction. Transactional models of reproductive skew may apply well to this and other simple systems.


Subject(s)
Behavior, Animal/physiology , Fishes/physiology , Models, Biological , Reproduction/physiology , Animals , Clutch Size , Eating/physiology , Female , Male , Social Dominance
4.
Comput Methods Programs Biomed ; 163: 79-85, 2018 Sep.
Article in English | MEDLINE | ID: mdl-30119859

ABSTRACT

OBJECTIVE: We compared three methods for estimating the individual peak height velocity (PHV) and age at peak height velocity (APHV) from the SuperImposition by Translation and Rotation (SITAR) model. METHODS: We fitted the SITAR model using simulated data and heights of 12 girls from the Chard Growth Study and obtained individual PHVs and APHVs from three methods: the model method, the quadratic function method and the numerical method, which are available in our newly developed R package"iapvbs". The mean, interquartile range, range of biases in estimated APHV and PHV as well as the rates of warning and unreasonable cases, i.e. estimated APHVs being outside the range of age measurements, from the three methods were presented and compared. RESULTS: When the growth curves of all individuals were well fitted by the SITAR model, all three methods estimated individual APHVs with similarly small biases, with a few unreasonable cases (0.16%) observed when the model method was used while more computation time required for the numerical method. When the growth curves of some individuals were not very well fitted, the model method generated more unreasonable individual APHV (8.15%) and more bias in PHV and APHV, compared to those estimated by the numerical method and quadratic function method. In line with the observations from the simulated data, the real data analysis demonstrated that the numerical method generated more reliable PHV and APHV for individuals with growth curve not well fitted by the SITAR model. CONCLUSION: The performance of different methods estimating individual APHV depends largely on how well the growth curves are fitted by the SITAR model. The quadratic function method is more superior when growth curves of all individuals are well fitted by the SITAR model; otherwise, the numerical method should be adopted for getting most robust estimates of PHV and APHV. The model method generates unreasonable APHV estimates, particularly when the growth curves are not well fitted.


Subject(s)
Anthropometry/methods , Body Height , Puberty/physiology , Adolescent , Age Factors , Algorithms , Child , Computer Simulation , Computers , Databases, Factual , Female , Humans , Male , Models, Theoretical , Programming Languages , Statistics as Topic , Young Adult
5.
Dis Esophagus ; 31(12)2018 Dec 01.
Article in English | MEDLINE | ID: mdl-29931323

ABSTRACT

Given the comparable strains of high-risk human papillomavirus (HPV) present in a subset of Barrett's dysplasia and esophageal adenocarcinoma as in head and neck squamous cell carcinomas and the anatomical proximity of both lesions, we hypothesized that oral sex may increase the risk of Barrett's dysplasia/esophageal adenocarcinoma. Therefore, we compared the sexual behavior of patients with Barrett's dysplasia/esophageal adenocarcinoma and controls (hospital, reflux, and Barrett's metaplasia) to explore a plausible mechanism of viral transmission to the lower esophagus. A hospital-based case-control study involving 36 Barrett's dysplasia/esophageal adenocarcinoma subjects and 55 controls with known HPV DNA status and markers of transcriptional activity i.e p16INK4A and E6/E7 mRNA of the esophageal epithelium was conducted to evaluate differences in sexual history (if any). Barrett's dysplasia/esophageal adenocarcinoma patients were more likely than controls to be positive for HPV DNA (18 of 36, 50% vs. 6/55, 11%, p for trend <0.0001), be male (P = 0.001) and in a relationship (P = 0.02). Viral genotypes identified were HPV 16 (n = 14), 18 (n = 2), 11 (n = 1) and 6 (n = 1). HPV exposure conferred a significantly higher risk for Barrett's dysplasia/esophageal adenocarcinoma as compared with hospital/reflux/Barrett's metaplasia controls (OR = 6.8, 95% CI: 2.1-23.1, adjusted P = 0.002). On univariate analysis, ≥6 lifetime oral sex partners were significantly associated with dysplastic Barrett's esophagus and adenocarcinoma (OR, 4.0; 95% CI: 1.2-13.7, P = 0.046). After adjustment for confounders, HPV exposure and men with ≥2 lifetime sexual partners were at significant risk for Barrett's dysplasia/esophageal adenocarcinoma. If these initial findings can be confirmed in larger studies, it could lead to effective prevention strategies in combating some of the exponential increase in the incidence of esophageal adenocarcinoma in the West.


Subject(s)
Adenocarcinoma/virology , Barrett Esophagus/virology , Esophageal Neoplasms/virology , Papillomaviridae/genetics , Sexual Behavior , Aged , Case-Control Studies , DNA, Viral/blood , Female , Gastroesophageal Reflux/virology , Genotype , Humans , Male , Middle Aged , Risk Factors
6.
J Adolesc Health ; 62(1): 100-106, 2018 01.
Article in English | MEDLINE | ID: mdl-29056438

ABSTRACT

PURPOSE: An intergenerational "mismatch," a transition from limited to plentiful living conditions over generations, may increase cardiovascular disease risks. In a migrant population within a homogenous culture, we tested the hypothesis that an intergenerational mismatch in childhood living condition is associated with higher body mass index (BMI) and blood pressure in childhood and adolescence. METHODS: We used data from 6,965 native born Chinese in Hong Kong (participated in "Children of 1997" birth cohort) and migrant Chinese born elsewhere in China in 1997 (N = 9,845). We classified children into those with intergenerational mismatch (child migrants or first-generation migrants) or those without (second+-generation migrants). Generalized estimating equations were used to examine the associations of migration status (child migrants, first-generation migrants or second+-generation migrants) with age- and sex-specific BMI z-score at 8-15 years and age-, sex-, and height-specific blood pressure z-score at 11-13 years, adjusted for sex, month of birth, and age. RESULTS: Compared with second+-generation migrants, first-generation migrants had higher diastolic blood pressure z-score (.04, 95% confidence interval (CI) .02, .06) and BMI z-score (.12, 95% CI .06, .18), whereas child migrants had higher diastolic blood pressure z-score (.03, 95% CI .01, .05) regardless of age at migration and higher BMI z-score if they had migrated in infancy (.17, 95% CI .11, .23). CONCLUSION: Different relations for blood pressure and BMI suggest that intergenerational mismatch and proximal exposures may have different impacts on adiposity and blood pressure.


Subject(s)
Adiposity/physiology , Blood Pressure , Body Mass Index , Intergenerational Relations , Adolescent , Cardiovascular Diseases/prevention & control , Child , Child Development , China/ethnology , Cohort Studies , Female , Hong Kong/epidemiology , Humans , Male , Socioeconomic Factors , Transients and Migrants/statistics & numerical data
10.
Hong Kong Med J ; 21(6): 499-510, 2015 Dec.
Article in English | MEDLINE | ID: mdl-26492835

ABSTRACT

OBJECTIVE: Disorders of sex development are due to congenital defects in chromosomal, gonadal, or anatomical sex development. The objective of this study was to determine the aetiology of this group of disorders in the Hong Kong Chinese population. SETTING: Five public hospitals in Hong Kong. PATIENTS: Patients with 46,XY disorders of sex development under the care of paediatric endocrinologists between July 2009 and June 2011. MAIN OUTCOME MEASURES: Measurement of serum gonadotropins, adrenal and testicular hormones, and urinary steroid profiling. Mutational analysis of genes involved in sexual differentiation by direct DNA sequencing and multiplex ligation-dependent probe amplification. RESULTS: Overall, 64 patients were recruited for the study. Their age at presentation ranged from birth to 17 years. The majority presented with ambiguous external genitalia including micropenis and severe hypospadias. A few presented with delayed puberty and primary amenorrhea. Baseline and post-human chorionic gonadotropin-stimulated testosterone and dihydrotestosterone levels were not discriminatory in patients with or without AR gene mutations. Of the patients, 22 had a confirmed genetic disease, with 11 having 5α-reductase 2 deficiency, seven with androgen insensitivity syndrome, one each with cholesterol side-chain cleavage enzyme deficiency, Frasier syndrome, NR5A1-related sex reversal, and persistent Müllerian duct syndrome. CONCLUSIONS: Our findings suggest that 5α-reductase 2 deficiency and androgen insensitivity syndrome are possibly the two most common causes of 46,XY disorders of sex development in the Hong Kong Chinese population. Since hormonal findings can be unreliable, mutational analysis of the SRD5A2 and AR genes should be considered the first-line tests for these patients.


Subject(s)
Asian People , Disorder of Sex Development, 46,XY/etiology , 3-Oxo-5-alpha-Steroid 4-Dehydrogenase/deficiency , 46, XX Disorders of Sex Development/etiology , Adolescent , Amenorrhea/etiology , Androgen-Insensitivity Syndrome/etiology , Child , Child, Preschool , Cholesterol Side-Chain Cleavage Enzyme/deficiency , Congenital Abnormalities/etiology , DNA Mutational Analysis , Dihydrotestosterone/blood , Disorder of Sex Development, 46,XY/blood , Disorder of Sex Development, 46,XY/urine , Female , Frasier Syndrome/etiology , Genital Diseases, Male/etiology , Gonadotropins/blood , Hong Kong , Humans , Hypospadias/etiology , Infant , Infant, Newborn , Male , Mullerian Ducts/abnormalities , Mutation , Penis/abnormalities , Puberty, Delayed/etiology , Steroidogenic Factor 1/genetics , Testosterone/blood
11.
Biomed Res Int ; 2015: 290861, 2015.
Article in English | MEDLINE | ID: mdl-26258135

ABSTRACT

Upland rice is important for sustainable crop production to meet future food demands. The expansion in area of irrigated rice faces limitations due to water scarcity resulting from climate change. Therefore, this research aimed to identify potential genotypes and suitable traits of upland rice germplasm for breeding programmes. Forty-three genotypes were evaluated in a randomised complete block design with three replications. All genotypes exhibited a wide and significant variation for 22 traits. The highest phenotypic and genotypic coefficient of variation was recorded for the number of filled grains/panicle and yields/plant (g). The highest heritability was found for photosynthetic rate, transpiration rate, stomatal conductance, intercellular CO2, and number of filled grains/panicle and yields/plant (g). Cluster analysis based on 22 traits grouped the 43 rice genotypes into five clusters. Cluster II was the largest and consisted of 20 genotypes mostly originating from the Philippines. The first four principle components of 22 traits accounted for about 72% of the total variation and indicated a wide variation among the genotypes. The selected best trait of the number of filled grains/panicle and yields/plant (g), which showed high heritability and high genetic advance, could be used as a selection criterion for hybridisation programmes in the future.


Subject(s)
Genetic Variation , Inheritance Patterns/genetics , Oryza/genetics , Quantitative Trait, Heritable , Cluster Analysis , Genotype , Principal Component Analysis
12.
Paediatr Perinat Epidemiol ; 29(4): 326-34, 2015 Jul.
Article in English | MEDLINE | ID: mdl-26111444

ABSTRACT

BACKGROUND: The role of infant growth in adiposity remains unclear. METHODS: We used multivariable linear regression, with inverse probability weighting and multiple imputation to account for loss to follow-up, in a population-representative Chinese birth cohort, 'Children of 1997' in Hong Kong, to examine, in terms births, the adjusted association of infant (birth to 12 months) weight growth trajectories with body mass index (BMI) (n = 6861, 88% follow-up), waist-to-height ratio (WHtR), and waist-to-hip ratio (WHR) (n = 5398, 69% follow-up) at ∼ 14 years. RESULTS: Infant weight growth trajectories had graded associations with adolescent BMI and WHtR but not with WHR, such that compared with adolescents born light with slow infant growth, adolescents born heavy with fast infant growth had higher BMI z-score [0.60, 95% confidence interval (CI) 0.49, 0.70], higher WHtR z-score (0.17, 95% CI 0.08, 0.26) but similar WHR z-score (-0.02, 95% CI -0.11, 0.08), adjusted for sex, gestational age, parental education, parental BMI, parental height, and parental place of birth. CONCLUSIONS: Varying associations of infant growth with different adiposity measures suggest a complex role of infant growth in long-term health, perhaps because infant growth, or its underlying drivers, influences build and body composition as well as adiposity.


Subject(s)
Adiposity , Obesity/epidemiology , Adolescent , Birth Weight , Body Mass Index , Child Development , Female , Hong Kong/epidemiology , Humans , Infant , Infant, Newborn , Male , Obesity/prevention & control , Prospective Studies , Risk Factors , Waist-Hip Ratio
13.
Neuroscience ; 290: 594-607, 2015 Apr 02.
Article in English | MEDLINE | ID: mdl-25637802

ABSTRACT

Modulation of corticostriatal synaptic activity by dopamine is required for normal sensorimotor behaviors. After loss of nigrostriatal dopamine axons in Parkinson's disease, l-3,4-dihydroxyphenlalanine (l-DOPA) and dopamine D2-like receptor agonists are used as replacement therapy, although these drugs also trigger sensitized sensorimotor responses including dyskinesias and impulse control disorders. In mice, we lesioned dopamine projections to the left dorsal striatum and assayed unilateral sensorimotor deficits with the corridor test as well as presynaptic corticostriatal activity with the synaptic vesicle probe, FM1-43. Sham-lesioned mice acquired food equivalently on both sides, while D2 receptor activation filtered the less active corticostriatal terminals, a response that required coincident co-activation of mGlu-R5 metabotropic glutamate and CB1 endocannabinoid receptors. Lesioned mice did not acquire food from their right, but overused that side following treatment with l-DOPA. Synaptic filtering on the lesioned side was abolished by either l-DOPA or a D2 receptor agonist, but when combined with a CB1 receptor antagonist, l-DOPA or D2 agonists normalized both synaptic filtering and behavior. Thus, high-pass filtering of corticostriatal synapses by the coordinated activation of D2, mGlu-R5, and CB1 receptors is required for normal sensorimotor response to environmental cues.


Subject(s)
Cerebral Cortex/physiopathology , Corpus Striatum/physiopathology , Dopamine/metabolism , Motor Activity/physiology , Parkinsonian Disorders/physiopathology , Synapses/physiology , Animals , Cerebral Cortex/drug effects , Corpus Striatum/drug effects , Dopamine Agents/pharmacology , Levodopa/pharmacology , Mice, Inbred C57BL , Motor Activity/drug effects , Neural Pathways/drug effects , Neural Pathways/physiopathology , Oxidopamine , Parkinsonian Disorders/drug therapy , Receptor, Cannabinoid, CB1/antagonists & inhibitors , Receptor, Cannabinoid, CB1/metabolism , Receptor, Metabotropic Glutamate 5/metabolism , Receptors, Dopamine D2/agonists , Receptors, Dopamine D2/metabolism , Synapses/drug effects , Tissue Culture Techniques
14.
Qual Life Res ; 23(8): 2343-53, 2014 Oct.
Article in English | MEDLINE | ID: mdl-24682669

ABSTRACT

BACKGROUND: This study sought to improve the predicative performance and goodness-of-fit of mapping models, as part of indirect valuation, by introducing cubic spline smoothing to map a group of health-related quality of life (HRQOL) measures onto a preference-based measure. METHODS: This study was a secondary analysis of a cross-sectional health survey data assessing the HRQOL for patients with colorectal neoplasms. Mapping functions of condition-specific functional assessment of cancer therapy-colorectal (FACT-C) onto preference-based SF-6D measure were developed using a dataset of 553 Chinese subjects with different stages of colorectal neoplasm. The missing values of FACT-C were imputed using multiple imputation. Then three widely applicable models (ordinary least square (OLS), Tobit and two-part models) were employed for the mapping function after applying the cubic spline smoothing on the data. For the evaluation of the effectiveness of cubic spline smoothing and multiple imputation, the goodness-of-fit and prediction performance of each model were compared. RESULTS: Analyses showed that the models fitted with transformed data from cubic spline smoothing offered better performance in goodness-of-fit and prediction than the models fitted with the original data. The values of [Formula: see text] were improved by over 10%, and the root mean square error and the mean absolute error were both reduced. The best goodness-of-fit and performance were achieved by OLS model using transformed data from cubic spline smoothing. CONCLUSIONS: Cubic spline smoothing and multiple imputation were recommended for the mapping of HRQOL measures onto the preference-based measure. Among the three mapping models, the simple-to-use OLS model had the best performance.


Subject(s)
Health Status , Psychometrics/methods , Quality of Life , Colorectal Neoplasms/psychology , Cross-Sectional Studies , Female , Humans , Least-Squares Analysis , Male , Middle Aged , Models, Statistical , Regression Analysis
15.
J Fish Biol ; 83(1): 207-13, 2013 Jul.
Article in English | MEDLINE | ID: mdl-23808701

ABSTRACT

Using the social clown anemonefish Amphiprion ocellaris, whether individuals exhibited consistency in activity levels, boldness and sociability in a paired context, and whether these three behavioural traits were positively correlated within a single behavioural syndrome, was investigated. The results highlight that consistent individual differences in behaviour are expressed in a social fish and suggest that consistent behavioural traits and behavioural syndromes could influence the structure and functioning of their societies.


Subject(s)
Behavior, Animal , Perciformes , Social Behavior , Animals , Female , Male
16.
Plant Dis ; 97(2): 287, 2013 Feb.
Article in English | MEDLINE | ID: mdl-30722331

ABSTRACT

In July 2011, a severe outbreak of pod and stem blight was observed on lima bean (Phaseolus lunatus L.) plants grown in the Cameron Highlands, located in Pahang State, Malaysia. Disease incidence varied from 33 to 75% in different fields. Pods and stems exhibited withered, light brown to reddish brown necrotic areas. Sub-circular and brown lesions were produced on the leaves. These lesions varied in size, often reaching a diameter of 1 to 2 cm. After tissue death, numerous pycnidia were observed on the surface of the pod or stem. The pycnidia diameter varied from 155 to 495 µm, averaging 265.45 µm, and on the surface of the pod or stem, pycnidia were often arranged concentrically or linearly, respectively. Pycnidiospores were hyaline, 1-celled, usually straight, and rarely, slightly curved. The α-spores varied from 5.5 to 9.0 × 2.5 to 4.0 µm; averaging 7.3 × 3.5 µm. The ß-spores found either alone or with pycnidiospores in pycnidia were slender, hyaline, nonseptate, and straight or curved. Size varied from 15.8 to 38.0 × 1.3 to 2.1 µm; averaging 25.86 × 1.8 µm. The colony characteristics were recorded from pure cultures grown on potato dextrose agar plates, and incubated in darkness for 7 days at 25 °C, then exposed to 16/8 h light and dark periods at 25°C for a further 14 to 21 days. Morphological characteristics of the colonies and spores on PDA matched those described for P. phaseolorum var. sojae (2). Colonies were white, compact, with wavy mycelium and stromata with pycnidia that contained abundant ß-spores. Sequence analysis of the ribosomal DNA internal transcribed spacer obtained from the Malaysian isolate FM1 (GenBank Accession No. JQ514150) using primers ITS5 and ITS4 (1) aligned with deposited sequences from GenBank confirmed identity and revealed 99% to 100% DNA similarity with P. phaseolorum strains (AY577815, AF001020, HM012819, JQ936148). The isolate FM1 was used for pathogenicity testing. Five non-infected detached leaves and pods of 4-week-old lima bean were surface sterilized and inoculated by placing 10 µl of conidial suspension (106 conidia ml-1) on the surface of leaves and pods using either the wound/drop or non-wound/drop method and distilled water used as control (3). The inoculated leaves and pods were incubated at 25 °C and 98% RH, and the experiment was performed twice. Disease reactions and symptoms were evaluated after inoculation. After one week, typical symptoms of pod and stem blight appeared with formation of pycnidia on the surface of the tissues, but not on non-inoculated controls. P. phaseolorum var. sojae was consistently reisolated from symptoms. To our knowledge, this is the first report of P. phaseolorum var. sojae causing pod and stem blight of lima bean in Malaysia. References: (1) R. Ford et al. Aust. Plant Pathol. 33:559, 2004. (2) G. L. Hartman et al. Compendium of Soybean Diseases. 4th ed. American Phytopathological Society, St. Paul, MN, 1999. (3) P. P. Than et al. Plant Pathol. 57:562, 2008.

17.
Plant Dis ; 97(6): 841, 2013 Jun.
Article in English | MEDLINE | ID: mdl-30722625

ABSTRACT

Soybean (Glycine max L.) is one of the most economically important crops in the world, and anthracnose is known to infect soybean in most countries. Colletotrichum truncatum is the common pathogen causing anthracnose of soybean. However, at least five species of Colletotrichum have been reported on soybean worldwide (2). In July 2010, anthracnose symptoms were observed on soybean in the experimental fields of the agriculture station in Ladang Dua, University Putra Malaysia located in Selangor state of Malaysia. Symptoms were initially observed on a few plants randomly within one field, but after 4 weeks, the disease was found in two additional fields scattered across an area of 1 km2. Pinkish-brown lesions were observed on the pods, and the formation of dark lesions on the leaves and stems was sometimes followed by stem girdling, dieback, and distorted growth. At later stages, numerous epidermal acervuli developed in the lesions, and mucilaginous conidial masses appeared during periods of high relative humidity. Conidia produced in acervuli were straight, cylindric, hyaline, and aseptate, with both ends rounded. Conidia measured (mean ± SD) 14.2 ± 0.6 × 3.6 ± 0.7 µm, and the L/W ratio was 3.95 µm. Six isolates of the fungus were obtained and identified as C. gloeosporioides on the basis of morphological characterization (3). The isolates were deposited in the University Putra of Malaysia Culture Collection (UPMCC). PDA cultures were white at first and subsequently became grayish to pink to reddish-brown. Amplification and sequence analysis of coding and none-coding regions of the ITS-rDNA (GenBank JX669450), actin (JX827430), ß-tubulin (JX827454), histone (JX827448), chitin synthase (JX827436), and glyceraldehyde-3-phosphate dehydrogenase (JX827442) obtained from the representative isolate, CGM50, aligned with deposited sequences from GenBank and revealed 99 to 100% sequence identity with C. gloeosporioides strains (JX258757, JX009790, GQ849434, HM575301, JQ005413, and JX00948 from GenBank). One representative isolate, CGM50, was used for pathogenicity testing. Four non-infected detached leaves and pods of 24-day-old G. max var. Palmetto were surface-sterilized and inoculated by placing 10 µl of a conidial suspension (106 conidia ml-1) using either the wound/drop or non-wound/drop method (4), with 10 µl distilled water as a negative control. Leaves and pods were incubated at 25°C, 98% RH. The experiment was repeated twice. Five days after inoculation, the development of typical field symptoms, including acervuli formation, occurred on the leaves and pods of inoculated plants, but not on the negative controls. A fungus with the same colony and conidial morphology as CGM50 was recovered from the lesions on the inoculated leaves and pods. Anthracnose caused by C. gloeosporioides on soybean plants has been reported previously in different countries, but not in Malaysia (3). Geographically, the climate of Malaysia is highly conducive to maintain and cause outbreaks of anthracnose all year round; thus, the development of management recommendations will be inevitable for anthracnose control. To our knowledge, this is the first report of C. gloeosporioides causing anthracnose on soybean in Malaysia. References: (1) U. Damm et al. Fungal Diversity 39:45, 2009. (2) S. L. Chen et al. J. Phytopathol. 154:654, 2006. (3) B. C. Sutton. The Genus Glomerella and its Anamorph Colletotrichum. CAB International, Wallingford, UK, 1992. (4) P. P. Than et al. Plant Pathol. 57:562, 2008. ERRATUM: A correction was made to this Disease Note on May 19, 2014. The author N. Soleimani was added.

18.
Plant Dis ; 97(5): 687, 2013 May.
Article in English | MEDLINE | ID: mdl-30722185

ABSTRACT

Bok choy (Brassica chinensis L.) is a temperate vegetable grown in the cool highland areas of Malaysia. In June 2010, vegetable growing areas of the Cameron Highlands, located in Pahang State, Malaysia, were surveyed for the prevalence of anthracnose disease caused by Colletotrichum species. Diseased samples were randomly collected from 12 infested fields. Anthracnose incidence on bok choy varied from 8 to 36% in different nursery fields. Disease symptoms initially appeared as small water-soaked spots scattered on the leaf petioles of young plants. As these spots increased in size, they developed irregular round spots that turned to sunken grayish brown lesions surrounded by brownish borders. When the lesions were numerous, leaves collapsed. Pale buff to salmon conidial mass and acervuli were observed on well-developed lesions. The acervuli diameter varied in size from 198 to 486 µm, averaging 278.5 µm. Morphological and cultural characteristics of the fungus were examined on potato dextrose agar incubated for 7 days at 25 ± 2°C under constant fluorescent light. Vegetative mycelia were hyaline, septate, branched, and 2 to 7 µm in diameter. The color of the fungal colonies was grayish brown. Conidia were hyaline, aseptate, falcate, apices acute, and 21.8 to 28.5 × 2.6 to 3.4 mm. Setae were pale brown to dark brown, 75 to 155 µm long, base cylindrical, and tapering towards the acute tip. Appressoria were solitary or in dense groups, light to dark brown, entire edge to lobed, roundish to clavate, 6.5 to 14 × 5.8 to 8.6 µm, averaging 9.2 × 6.8 µm, and had a L/W ratio of 1.35. Based on the keys outlined by Mordue 1971 (2) and Sutton 1980 (3), the characteristics of this fungus corresponded to Colletotrichum capsici. Sequence analysis of the ITS-rDNA obtained from the Malaysian strain CCM3 (GenBank Accession No. JQ685746) using primers ITS5 and ITS4 (1) when aligned with deposited sequences from GenBank revealed 99 to 100% sequence identity with C. capsici strains (DQ286158, JQ685754, DQ286156, GQ936210, and GQ369594). A representative strain CCM3 was used for pathogenicity testing. Four non-infected detached leaves of 2-week-old B. chinensis were surface-sterilized and inoculated by placing 10 µl of conidial suspension (106 conidia ml-1) using either the wound/drop or non-wound/drop method, and distilled water was used as a control (1). Leaves were incubated at 25°C, 98% RH. The experiment was repeated twice. Five days after inoculation, typical anthracnose symptoms with acervuli formation appeared on the surface of tissues inoculated with the spore suspension, but not on the water controls. A fungus with the characteristics of C. capsici was recovered from the lesions on the inoculated leaves. Anthracnose caused by C. capsici has been reported on different vegetable crops, but not on bok choy (3). To the best of our knowledge, this is the first report of C. capsici causing anthracnose on bok choy in Malaysia. References: (1) R. Ford et al. Aust. Plant Pathol. 33:559, 2004. (2) J. E. M. Mordue. CMI Description of Pathogenic Fungi and Bacteria. Commonwealth Mycol. Inst., Kew, UK. 1971. (3) B. C. Sutton. The Genus Glomerella and its anamorph Colletotrichum. CAB International, Wallingford, UK, 1992. (4) P. P. Than et al. Plant Pathol. 57:562, 2008.

19.
Plant Dis ; 97(1): 143, 2013 Jan.
Article in English | MEDLINE | ID: mdl-30722276

ABSTRACT

In April and June 2010, coconut seedlings with symptoms of very slow growth, yellowing of leaves, and general abnormal leaf growth were observed in germination beds in Teluk Intan, Perak, Malaysia. The roots were soft, rotten, and brown, extending upward and downward from these lesions. Rhizomorphs and basidiocarps were produced on coconut seeds near the germination eye and identified as Marasmiellus palmivorus according description by Turner (2). Three isolates were obtained by plating surface sterilized symptomatic roots and basidiocarp on malt extract agar (MEA) amended with 85% lactic acid (1 ml added to 11 of the medium). To confirm the identity of the fungus, genomic DNA was extracted from mycelia and basidiocarps of isolates and the large subunit (LSU) region was amplified and sequenced using LR0R/LR7 primers (3). All isolates had identical LSU sequences (GenBank Accession No. JQ654233 to JQ654235). Sequences were identical to each other and 99% similar to a M. palmivorus sequence deposited in the NCBI database (Accession No. AY639434).To confirm pathogenicity, three isolates of M. palmivorus that were obtained from symptomatic plant tissue was inoculated onto seeds of Malaysian Red Dwarf variety. Each isolate was grown in 100 ml of malt extract broth in 250 ml Erlenmeyer flasks and incubated at 27 ± 2°C for 5 days on an orbital shaker (125 rpm). The resulting culture was passed through two layers of sterile cloth. Mycelial suspension was obtained by blending mycelia in 100 ml of sterile water. Seeds were sterilized by soaking in 10% v/v sodium hypochlorite in distilled water for 3 min. The seeds were then rinsed three times over running tap water. The calyx portion of the seed was removed and five holes were made around the germination eye. The seeds were inoculated by injecting 2 ml of suspension into each hole. The control seeds were inoculated with sterile distilled water only. The seeds were transferred to 40-cm diameter plastic pots containing a mixture of sand, soil, and peat in the ratio of 3:2:1, respectively, and steam treated at 100°C for 1.5 h. Pots were placed in the glasshouse with normal exposures to day-night cycles, temperatures of 29 ± 4°C, and high relative humidity (85 to 95%) achieved by spraying water twice daily. After 2 months, 75% of the inoculated seeds failed to germinate. It was speculated that the artificial inoculum was higher than under germination bed conditions. Rhizomorphs and basidiocarps were produced on husk seeds near the germination eye. Seedlings that emerged successfully developed symptoms similar to those observed in the germination bed. No symptoms developed in the noninoculated seeds and seedlings. At 80 days post inoculation, basidiocarps were observed emerging from three diseased seedlings near the germination eye. Three reisolations were made on MEA from root lesions surface sterilized. Pathogenicity tests and LSU sequence analyses indicated that M. palmivorus is the causal agent of the symptoms observed on coconut seedlings. M. palmivorus was first recorded on coconuts and oil palm in the 1920s (1) and attacks the fruit and the petiole on oil palm (2). To our knowledge, this is the first report of M. palmivorus causing post-emergence damping off on coconut seedlings. References: (1) K. G. Singh. A check-list of host and diseases in Malaysia. Ministry of Agriculture and Fisheries, Malaysia, 1973. (2) P. D. Turner. Oil palm diseases and disorders. Oxford University Press. 1981. (3) R. Vilgalys et al. J. Bacteriol. 172:4238, 1990.

20.
Plant Pathol J ; 29(1): 10-6, 2013 Mar.
Article in English | MEDLINE | ID: mdl-25288924

ABSTRACT

Hevea brasiliensis is a natural source of rubber and an important plantation tree species in Malaysia. Leaf blight disease caused by Fusicoccum substantially reduces the growth and performance of H. brasiliensis. The aim of this study was to use a combination of both morphological characteristics and molecular data to clarify the taxonomic position of the fungus associated with leaf blight disease. Fusicoccum species were isolated from infected leaves collected from plantations at 3 widely separated locations - Selangor, Perak, and Johor states - in Peninsular Malaysia in 2010. All the isolates were identified according to their conidial patterns and DNA sequences generated from internal transcribed spacers (ITS1 and ITS2), the 5.8S rRNA, and an unknown locus (BotF15) containing microsatellite repeats. Based on taxonomic and sequence data, Neofusicoccum ribis was identified as the main cause of leaf blight disease in H. brasiliensis in commercial plantations in Malaysia. A pathogenicity trial on detached leaves further confirmed that N. ribis causes leaf blight disease. N. ribis is an important leaf pathogen, and its detection in Malaysia has important implications for future planting of H. brasiliensis.

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