Lilian Vrijmoed - Academia.edu (original) (raw)

Papers by Lilian Vrijmoed

Can J Bot, 1994

The new genus Tirispora, with the single species Tirispora unicaudata, is described from an inter... more The new genus Tirispora, with the single species Tirispora unicaudata, is described from an intertidal mangrove plant Acanthus ilicifolius in Hong Kong. The genus is compared with other genera with polar unfurling appendages: Aniptodera, Cucullosporella, Halosarpheia, Moana, Ophiodeira, and Trichomaris. Key words: ascus, Halosphaeriales, spore appendages, taxonomy, Tirispora gen.nov., ultrastructure.

Transactions and Proceedings of the Botanical Society of Edinburgh and Botanical Society of Edinburgh Transactions, Apr 22, 2009

ABSTRACT

Canadian Journal of Botany, 2003

Conidiogenesis and conidial appendage ontogeny of the coelomycete Bartalinia robillardoides Tassi... more Conidiogenesis and conidial appendage ontogeny of the coelomycete Bartalinia robillardoides Tassi was studied at the light microscope, scanning electron microscope, and transmission electron microscope levels. Conidiogenesis in B. robillardoides is holoblastic. Appendage ontogeny begins as a cellular outgrowth of the apical and the basal cells of the young conidium, the former developing prior to the basal appendage. Conidia detach from the conidiogenous cells schizolytically. Mature conidial cell walls comprise two layers: an outer electron-dense layer, 30-38 nm, and an inner less electron-dense layer, 100-125 nm. The apical appendages arise from an outgrowth of the apical cell, which then branches to form the appendages. The single basal appendage arises from the junction between the basal cell of the conidium and the conidiogenous cell prior to conidial detachment from the conidiogenous cell, as an outgrowth of the conidial cell wall. Conidial appendage ontogeny is compared with those of other coelomycetes.

Acta Crystallogr E Struct Rep, 2006

Mycological Research, Jun 1, 1999

Mass mortality among pond cultured red drum (Sciaenops ocellatus) was observed in Hong Kong. Affe... more Mass mortality among pond cultured red drum (Sciaenops ocellatus) was observed in Hong Kong. Affected fish were lethargic and lost their appetite but no lesions on the body surface were apparent. Patches of white to brownish cottony growth on the gills of affected fish were observed and microscopic examination revealed mats of hyaline mycelia with mature zoosporangia and oogonia which were identified as Saprolegnia diclina. During induced sporulation, production of primary and secondary zoospores, oogonia, and antheridia were observed. A physiological study of the growth and sporulation of a representative isolate determined its optimum growth requirements. The isolate can grow from pH 4 to 10, in distilled water, at salinities of 5-30 =, and temperatures of 4-30m. Maximum growth was observed at pH 5 and 8-10, at salinities of 5-10 =, and 25-30m. Production of zoosporangia only occurred in distilled water, 5 and 10 = salinities, with zoospores released in distilled water and 5 = salinity. Zoospore release was also observed from 4 to 30m with greater abundance at 25 and 30m, while oogonia and antheridia were produced in distilled water and from 5 to 30 = salinities and at 20-30m. Mycotic infections by members of the Saprolegniaceae, commonly known as saprolegniosis, are widely reported in freshwater fish (Carballo & Mun4 oz, 1991). These straminipilous organisms, which include Saprolegnia, Achlya, and Aphanomyces (Yuasa & Hatai, 1994), infect eggs, fry, fingerlings, and adult of fish (Neish & Hughes, 1980 ; Srivastava, 1980 ; Jeney & Jeney, 1995). Stress factors (e.g. mechanical injury after handling, extreme pH levels, prolonged exposure to low water temperatures), lack of food, and presence of other microbial infections (e.g. bacterial, viral) are reported to increase the susceptibility of fish to fungal infections (Ogbonna & Alabi, 1991 ; Carballo & Mun4 oz, 1991). Infection is Table 1. Parasitic Saprolegnia species isolated from different freshwater fish hosts Fish hosts* Reference(s)

Chemistry of Natural Compounds, Jul 1, 2010

A new griseofulvin derivative, 7-chloro-2c,5,6-trimethoxy-6c-methylspiro(benzofuran-2(3H),1c-(2) ... more A new griseofulvin derivative, 7-chloro-2c,5,6-trimethoxy-6c-methylspiro(benzofuran-2(3H),1c-(2) cyclohexene)-3,4c-dione (1), together with the known 2-acetyl-7-methoxybenzofuran (2), was isolated from the marinederived mangrove endophytic fungus Sporothrix sp. (No. 4335). The structure of new compound 1 was elucidated by analysis of spectroscopic data.

Early detection and provision of feedback on learners' performance are essential mechanisms t... more Early detection and provision of feedback on learners' performance are essential mechanisms to allow learners to take prompt action to improve their approach to learning. Although students may learn how they perform in mid-term quizzes, the results cannot reflect how they might perform in the final examination. However, quiz results with set answers cannot illustrate the comprehensive skills and knowledge that are expected in university study. This paper reports on the use of a diagnostic tool to analyse the process of students working on a discovery-embedded assessment task in the collaborative learning environment of a microbiology course. The diagnostic tool identified that those learners who performed less well in the assessment tasks also performed less well in the final examination. This tool can provide early detection of those facing learning challenges in comprehensive assessment tasks, so that educators can provide appropriate support.

Magnetic Resonance in Chemistry, 2008

One new compound 6-demethylvermistatin (1), together with two known compounds, the penicillide de... more One new compound 6-demethylvermistatin (1), together with two known compounds, the penicillide derivatives (2) and (3) were isolated from the mangrove fungus Guignardia sp. No. 4382 obtained from the South China Sea. Their structures were assigned using high-resolution electron ionization mass spectrometry(HREIMS), (1)H and (13)C NMR spectra, DEPT, and by 2D COSY, HMQC, and HMBC experiments. The absolute configuration of 1 was established by comparison of its CD with that of vermistatin.

The Journal of Organic Chemistry, 2001

Five unique metabolites, xyloketals A (1), B (2), C (3), D (4), and E (5), and the known 6 were i... more Five unique metabolites, xyloketals A (1), B (2), C (3), D (4), and E (5), and the known 6 were isolated from mangrove fungus Xylaria sp. (no. 2508), obtained from the South China Sea. The structures of these compounds were elucidated by spectroscopic and X-ray diffraction experiments. Xyloketal A is a ketal compound with a C(3) symmetry and xyloketals B-E are its analogues. It was found that xytoketal C slowly rearranged to xytoketal B in DMSO-d(6)() solution at room temperature. Xyloketal A exhibited the activity of inhibiting acetylcholine esterase.

Journal of Natural Products, 2008

Helvetica Chimica Acta, 2007

Chinese Journal of Chemistry, 2009

ABSTRACT

Canadian Journal of Botany, 2004

Two new marine fungi from woody substrata collected on sandy beaches of the Pearl River Estuary i... more Two new marine fungi from woody substrata collected on sandy beaches of the Pearl River Estuary in southern China (brackish water) and the East Coast Beach in Singapore (fully saline seawater) are described. A new genus, Sablecola E.B.G. Jones, K.L. Pang & Vrijmoed, is introduced to accommodate Sablecola chinensis E.B.G. Jones, K.L. Pang & Vrijmoed, sp. nov, with ascospores having two polar and four equatorial, flattened, attenuate, strap-like appendages with parallel striations, which disintegrate into fine threads when mounted in seawater. Sablecola chinensis can be differentiated from other taxa with a similar ascospore appendage arrangement, such as Halosphaeria and Ocostaspora, by its ascospore appendage morphology. Remispora minuta E.B.G. Jones, K.L. Pang & Vrijmoed, sp. nov. has hyaline and membranous ascomata bearing ascospores with moustache-shaped appendages that are characteristic of Remispora species. This species cannot be accommodated in Haligena, a genus with spoon-sh...

Bioresource Technology, Dec 1, 2010

A ten-month study was carried out in an experimental farm in Hong Kong to investigate the changes... more A ten-month study was carried out in an experimental farm in Hong Kong to investigate the changes in the forms and content of carbon, nitrogen, phosphorus and potassium of the pig manure under a pig-on-litter (POL) system. This system, known as in-situ composting, utilizes a mixture of sawdust and a commercial bacterial product as the bedding material on which pigs are kept and the pig excreta are decomposed within the bedding. The effects of the commercial bacterial product recommended by the POL system (the treated group) on nutrient transformation of the pig manure were evaluated and compared with the control group (without any bacterial product). It was found that there was no significant difference between the treated and the control groups in terms of the concentrations of organic carbon, total and extractable N, P and K of the sawdust pig manure litter samples. The patterns of how these nutrient changed with the experimental time were similar between the treated and the control groups. The concentrationsof total N, N~ +-N, total and extractable P and K increased rapidly at the beginning of the experiment and the rate of these accumulations became slower towards the end of the study. On the other hand, total organic carbon content of the litter samples declined dramatically in the first few weeks, with C values dropped from an initial 40% to 31 % at week 10. Further decrease in total carbon concentration was observed as the experiment proceeded. A very drastic drop of the C:N ratio. was found within the first few days, from an initial 175:1 decreased to 40:1 within one day then further dropped to 14:1 at the end of week 1 in both treated and control groups. At the end of the experiment, the C:N ratio reached a very low value (10: 1). These results suggest that (1) the commercial bacterial product did not have any significant effect on nutrient transformation of pig manure under the POL system; (2) the nutrients released from pig excreta were rapidly assimilated and immobilized by microorganisms colonized within the bedding material, with an accumulation of total nutrients (N, P and K) but a decline in C throughout the experiment; and (3) the bedding material of the POL system appeared to become more stable and mature as the study continued, the samples collected at later stage of the experiment had a more constant nutrient level and a very narrow C:N ratio.

Can J Bot, 1994

The new genus Tirispora, with the single species Tirispora unicaudata, is described from an inter... more The new genus Tirispora, with the single species Tirispora unicaudata, is described from an intertidal mangrove plant Acanthus ilicifolius in Hong Kong. The genus is compared with other genera with polar unfurling appendages: Aniptodera, Cucullosporella, Halosarpheia, Moana, Ophiodeira, and Trichomaris. Key words: ascus, Halosphaeriales, spore appendages, taxonomy, Tirispora gen.nov., ultrastructure.

Transactions and Proceedings of the Botanical Society of Edinburgh and Botanical Society of Edinburgh Transactions, Apr 22, 2009

ABSTRACT

Canadian Journal of Botany, 2003

Conidiogenesis and conidial appendage ontogeny of the coelomycete Bartalinia robillardoides Tassi... more Conidiogenesis and conidial appendage ontogeny of the coelomycete Bartalinia robillardoides Tassi was studied at the light microscope, scanning electron microscope, and transmission electron microscope levels. Conidiogenesis in B. robillardoides is holoblastic. Appendage ontogeny begins as a cellular outgrowth of the apical and the basal cells of the young conidium, the former developing prior to the basal appendage. Conidia detach from the conidiogenous cells schizolytically. Mature conidial cell walls comprise two layers: an outer electron-dense layer, 30-38 nm, and an inner less electron-dense layer, 100-125 nm. The apical appendages arise from an outgrowth of the apical cell, which then branches to form the appendages. The single basal appendage arises from the junction between the basal cell of the conidium and the conidiogenous cell prior to conidial detachment from the conidiogenous cell, as an outgrowth of the conidial cell wall. Conidial appendage ontogeny is compared with those of other coelomycetes.

Acta Crystallogr E Struct Rep, 2006

Mycological Research, Jun 1, 1999

Mass mortality among pond cultured red drum (Sciaenops ocellatus) was observed in Hong Kong. Affe... more Mass mortality among pond cultured red drum (Sciaenops ocellatus) was observed in Hong Kong. Affected fish were lethargic and lost their appetite but no lesions on the body surface were apparent. Patches of white to brownish cottony growth on the gills of affected fish were observed and microscopic examination revealed mats of hyaline mycelia with mature zoosporangia and oogonia which were identified as Saprolegnia diclina. During induced sporulation, production of primary and secondary zoospores, oogonia, and antheridia were observed. A physiological study of the growth and sporulation of a representative isolate determined its optimum growth requirements. The isolate can grow from pH 4 to 10, in distilled water, at salinities of 5-30 =, and temperatures of 4-30m. Maximum growth was observed at pH 5 and 8-10, at salinities of 5-10 =, and 25-30m. Production of zoosporangia only occurred in distilled water, 5 and 10 = salinities, with zoospores released in distilled water and 5 = salinity. Zoospore release was also observed from 4 to 30m with greater abundance at 25 and 30m, while oogonia and antheridia were produced in distilled water and from 5 to 30 = salinities and at 20-30m. Mycotic infections by members of the Saprolegniaceae, commonly known as saprolegniosis, are widely reported in freshwater fish (Carballo & Mun4 oz, 1991). These straminipilous organisms, which include Saprolegnia, Achlya, and Aphanomyces (Yuasa & Hatai, 1994), infect eggs, fry, fingerlings, and adult of fish (Neish & Hughes, 1980 ; Srivastava, 1980 ; Jeney & Jeney, 1995). Stress factors (e.g. mechanical injury after handling, extreme pH levels, prolonged exposure to low water temperatures), lack of food, and presence of other microbial infections (e.g. bacterial, viral) are reported to increase the susceptibility of fish to fungal infections (Ogbonna & Alabi, 1991 ; Carballo & Mun4 oz, 1991). Infection is Table 1. Parasitic Saprolegnia species isolated from different freshwater fish hosts Fish hosts* Reference(s)

Chemistry of Natural Compounds, Jul 1, 2010

A new griseofulvin derivative, 7-chloro-2c,5,6-trimethoxy-6c-methylspiro(benzofuran-2(3H),1c-(2) ... more A new griseofulvin derivative, 7-chloro-2c,5,6-trimethoxy-6c-methylspiro(benzofuran-2(3H),1c-(2) cyclohexene)-3,4c-dione (1), together with the known 2-acetyl-7-methoxybenzofuran (2), was isolated from the marinederived mangrove endophytic fungus Sporothrix sp. (No. 4335). The structure of new compound 1 was elucidated by analysis of spectroscopic data.

Early detection and provision of feedback on learners' performance are essential mechanisms t... more Early detection and provision of feedback on learners' performance are essential mechanisms to allow learners to take prompt action to improve their approach to learning. Although students may learn how they perform in mid-term quizzes, the results cannot reflect how they might perform in the final examination. However, quiz results with set answers cannot illustrate the comprehensive skills and knowledge that are expected in university study. This paper reports on the use of a diagnostic tool to analyse the process of students working on a discovery-embedded assessment task in the collaborative learning environment of a microbiology course. The diagnostic tool identified that those learners who performed less well in the assessment tasks also performed less well in the final examination. This tool can provide early detection of those facing learning challenges in comprehensive assessment tasks, so that educators can provide appropriate support.

Magnetic Resonance in Chemistry, 2008

One new compound 6-demethylvermistatin (1), together with two known compounds, the penicillide de... more One new compound 6-demethylvermistatin (1), together with two known compounds, the penicillide derivatives (2) and (3) were isolated from the mangrove fungus Guignardia sp. No. 4382 obtained from the South China Sea. Their structures were assigned using high-resolution electron ionization mass spectrometry(HREIMS), (1)H and (13)C NMR spectra, DEPT, and by 2D COSY, HMQC, and HMBC experiments. The absolute configuration of 1 was established by comparison of its CD with that of vermistatin.

The Journal of Organic Chemistry, 2001

Five unique metabolites, xyloketals A (1), B (2), C (3), D (4), and E (5), and the known 6 were i... more Five unique metabolites, xyloketals A (1), B (2), C (3), D (4), and E (5), and the known 6 were isolated from mangrove fungus Xylaria sp. (no. 2508), obtained from the South China Sea. The structures of these compounds were elucidated by spectroscopic and X-ray diffraction experiments. Xyloketal A is a ketal compound with a C(3) symmetry and xyloketals B-E are its analogues. It was found that xytoketal C slowly rearranged to xytoketal B in DMSO-d(6)() solution at room temperature. Xyloketal A exhibited the activity of inhibiting acetylcholine esterase.

Journal of Natural Products, 2008

Helvetica Chimica Acta, 2007

Chinese Journal of Chemistry, 2009

ABSTRACT

Canadian Journal of Botany, 2004

Two new marine fungi from woody substrata collected on sandy beaches of the Pearl River Estuary i... more Two new marine fungi from woody substrata collected on sandy beaches of the Pearl River Estuary in southern China (brackish water) and the East Coast Beach in Singapore (fully saline seawater) are described. A new genus, Sablecola E.B.G. Jones, K.L. Pang & Vrijmoed, is introduced to accommodate Sablecola chinensis E.B.G. Jones, K.L. Pang & Vrijmoed, sp. nov, with ascospores having two polar and four equatorial, flattened, attenuate, strap-like appendages with parallel striations, which disintegrate into fine threads when mounted in seawater. Sablecola chinensis can be differentiated from other taxa with a similar ascospore appendage arrangement, such as Halosphaeria and Ocostaspora, by its ascospore appendage morphology. Remispora minuta E.B.G. Jones, K.L. Pang & Vrijmoed, sp. nov. has hyaline and membranous ascomata bearing ascospores with moustache-shaped appendages that are characteristic of Remispora species. This species cannot be accommodated in Haligena, a genus with spoon-sh...

Bioresource Technology, Dec 1, 2010

A ten-month study was carried out in an experimental farm in Hong Kong to investigate the changes... more A ten-month study was carried out in an experimental farm in Hong Kong to investigate the changes in the forms and content of carbon, nitrogen, phosphorus and potassium of the pig manure under a pig-on-litter (POL) system. This system, known as in-situ composting, utilizes a mixture of sawdust and a commercial bacterial product as the bedding material on which pigs are kept and the pig excreta are decomposed within the bedding. The effects of the commercial bacterial product recommended by the POL system (the treated group) on nutrient transformation of the pig manure were evaluated and compared with the control group (without any bacterial product). It was found that there was no significant difference between the treated and the control groups in terms of the concentrations of organic carbon, total and extractable N, P and K of the sawdust pig manure litter samples. The patterns of how these nutrient changed with the experimental time were similar between the treated and the control groups. The concentrationsof total N, N~ +-N, total and extractable P and K increased rapidly at the beginning of the experiment and the rate of these accumulations became slower towards the end of the study. On the other hand, total organic carbon content of the litter samples declined dramatically in the first few weeks, with C values dropped from an initial 40% to 31 % at week 10. Further decrease in total carbon concentration was observed as the experiment proceeded. A very drastic drop of the C:N ratio. was found within the first few days, from an initial 175:1 decreased to 40:1 within one day then further dropped to 14:1 at the end of week 1 in both treated and control groups. At the end of the experiment, the C:N ratio reached a very low value (10: 1). These results suggest that (1) the commercial bacterial product did not have any significant effect on nutrient transformation of pig manure under the POL system; (2) the nutrients released from pig excreta were rapidly assimilated and immobilized by microorganisms colonized within the bedding material, with an accumulation of total nutrients (N, P and K) but a decline in C throughout the experiment; and (3) the bedding material of the POL system appeared to become more stable and mature as the study continued, the samples collected at later stage of the experiment had a more constant nutrient level and a very narrow C:N ratio.