In vitro adhesion and invasion by Cladosporium sphaerospermum in human bronchial epithelial cells (BEAS-2B) and human pulmonary alveolar epithelial cells (HPAEpiC)

@#Cladosporium spores are ubiquitous in indoor and outdoor environment and may potentially trigger allergic responses upon inhalation. To date, there is limited investigation on the fate of Cladosporium spores after being inhaled into the respiratory tract. This study was conducted to investigate the interaction of Cladosporium sphaerospermum with Human Bronchial Epithelial Cells (BEAS-2B) and Human Pulmonary Alveolar Epithelial Cells (HPAEpiC). C. sphaerospermum conidia were harvested and co-cultured with BEAS-2B or HPAEpiC cells for 72 hours. At each time point (30 minutes, 2, 4, 24, 48 and 72 hours), adherence and invasion of the cells by C. sphaerospermum conidia (and hyphae) were investigated by immunofluorescence staining. This study demonstrated the adherence and internalization of C. sphaerospermum conidia within these epithelial cells. In addition, the conidia were able to germinate and invade the epithelial cells. The ability of the fungal conidia to adhere, internalize, germinate and invade both the bronchial and alveolar epithelial cells of the respiratory tract in vitro might contribute to the understanding of the pathogenesis of Cladosporium in respiratory infection and allergy in vivo. INTRODUCTION Cladosporium species is a member of the phylum Ascomycota. The common species include C. herbarum, C. cladosporioides and C. sphaerospermum. This genus has worldwide distribution. Aerobiological studies reported that majority of fungal spores in outdoor air is from the phyla Ascomycota and Basidiomycota, while Cladosporium is one of the most studied allergenic Ascomycetes fungi (Knutsen et al., 2012). Cladosporium spores are found abundantly in indoors and outdoors at approximately 18/m3 and 141/m3 respectively (Codina et al., 2008). As an imperfect dematiaceous fungus, Cladosporium species causes opportunistic infections such

Morphology of Glycycometus malaysiensis, a domestic mite in Malaysia

@#Glycycometus malaysiensis is an allergenic domestic mite found in houses. G. malaysiensis is known to be highly similar to and is often mistaken as Blomia tropicalis, one of the major house dust mite species that causes asthma and allergic diseases in many tropical and subtropical regions. It was also suggested that these mites cross-react with each other and that the prevalence of G. malaysiensis might be higher than previous reports. A review on the taxonomic keys as well as light and scanning electron micrographs of G. malaysiensis are presented to appreciate the fine morphological structures of G. malaysiensis. The mouth, setae, legs (trochanter, femur, genu, tibia and tarsus) and the sexual organs (genital openings, genital setae and genital suckers) of G. malaysiensis are outlined. The morphology of G. malaysiensis is also compared with that of B. tropicalis to delineate the key features for the differentiation between these two mite species.

Parasites in soil samples from Signy island, Antarctica

@#Studies on parasite populations in Antarctic soils are scarce and thus little is known about the threat of these parasites towards either the natural fauna or human visitors. However, human presence in Antarctica, mainly through research and tourism, keeps increasing over time, potentially exposing visitors to zoonotic infections from Antarctic wildlife and environment. Most available literature to date has focused on faecal samples from Antarctic vertebrates. Therefore, this study addressed the possible presence of parasites in Antarctic soil that may be infectious to humans. Soil samples were obtained from five locations on Signy Island (South Orkney Islands, maritime Antarctic), namely North Point and Gourlay Peninsula (penguin rookeries), Pumphouse (relic coal-powered pump house), Jane Col (barren high altitude fellfield) and Berntsen Point (low altitude vegetated fellfield close to current research station). Approximately 10% of the soil samples (14/135) from 3 out of the 5 study sites had parasites which included Diphyllobotridae spp. eggs, Cryptosporidium sp., an apicomplexan protozoa (gregarine), Toxoplasma gondii, helminths (a cestode, Tetrabothrius sp., and a nematode larva) and mites. The presence of parasites in the 3 sites are most likely due to the presence of animal and human activities as two of these sites are penguin rookeries (North Point and Gourlay Peninsula) while the third site (Pumphouse Lake) has human activity. While some of the parasite species found in the soil samples appear to be distinctive, there were also parasites such as Cryptosporidium and Toxoplasma gondii that have a global distribution and are potentially pathogenic.

Isolation and identification of mites associated with raw and commercial farm edible bird nests

The global demand for edible bird nests (EBNs) is high, especially from Hong Kong and Peoples Republic of China. Recently, this industry was greatly affected when China banned the import of all the EBNs from Malaysia (except for canned version) due to detection of high levels of nitrites. Several cases of anaphylaxis following ingestion of EBNs were reported. The source(s) of these allergens remain unknown. Mites have been reported to trigger allergic responses. Hence, this study was designed to quantify, isolate and identify the mites that are associated with EBNs. The raw EBNs were purchased from swiftlet farms in five locations in Peninsular Malaysia while the commercial nests were purchased from five different Chinese traditional medicinal shops. The average mite density of all the raw nests was 285 ± 603 mites per gram of EBN while the commercial nests had a much lower mean value of 21 ± 32 mites per gram of EBN (p = 0.082). Among the raw EBNs, the nests from Kajang had the highest average mite density (946 ± 1443 mites/g of EBN) whereas the nests from Kuala Sanglang had the lowest (54 ± 34 mites/g of EBN). Among the commercial EBNs, the nests from Company D had the highest average mite density (76 ± 18 mites/g of EBN) whereas the nests from Company A were free of mites. Overall, the average densities of mites in the raw nests obtained from southern regions of Malaysia (Selangor and Johor) were higher than those nests obtained from the northern regions (Kedah and Kelantan). Thirty types of mites were isolated from both the raw and commercial nests. Among these, some are probably feather mites (Eustathia cultrifer, Pteroherpus garrulacis, Pterodectes amaurochalinus, Laminalloptes sp., Berlesella alata and Neochauliacia sp.), house dust and storage mites (Suidasia sp., Austroglycyphagus sp., and Aleuroglyphus ovatus), mesostigmatid mites (Dermanyssus sp.), prostigmatid mites (Cheyletus sp., tarsonemid and cunaxid mites), astigmatid mites (Collocalidectes sp., Streetacarus sp. and Hemisarcoptes sp.) and oribatid mites. This study provides baseline information on the density and type of mites that are probably associated with EBNs. This study also heightens the importance of mites as a possible source of EBN-associated anaphylaxis.

Sero-prevalence study of IgE responses to allergens from Malaysian house dust (HDM) and storage mites (SM)

Allergens of Dermatophagoides and Blomia species are well-characterized but not for other species. This study was conducted to determine the prevalence of allergic sensitization to house dust (HDM) and storage mites (SM). One hundred adult subjects (aged > 18) were recruited. The mite specific IgE of all allergic subjects were higher compared with healthy subjetcs despite being not statistically significant except for D. farinae and G. malaysiensis. The mean serum IgE levels against HDM and SM for allergic subjects were significantly higher compared with those in healthy subjects. They were mainly sensitized to Dermatophagoides farinae (35%) and Glycycometus malaysiensis (37%). Immunoblots revealed not all allergic subjects showed positive immuno-reactivity against the mites tested. Single or multiple bands were observed for different species. The subjects were commonly sensitized to Group 2 (9-12 kDa), 10 (38 kDa) and 18 (40-48 kDa) allergens. Twenty-one out of 60 allergic subjects were sensitized to either one or more species. The majority of them (71%) were sensitized to single species. The allergic subjects were mainly sensitized to D. pteronyssinus, followed by Tyrophagus putrecentiae and Aleuroglyphus ovatus. Seven were solely sensitized to HDM while 10 were solely sensitized to SM. Four subjects were sensitized to both. Preadsorption study revealed no cross-reactivity. There was difference between the prevalence and reactivity to allergens of HDM and SM in these subjects. Both ELISA and immunoblot did not correlate well but can complement each other in improving the detection of mite allergens to the species level.

Antigenic profile of Blomia tropicalis, Aleuroglyphus ovatus and Glycycometus malaysiensis

House dust mites and storage mites are well-known causes for allergenic diseases. The aim of this study was to investigate the immunogenic sites of Blomia tropicalis, Aleurogyphus ovatus and Glycycometus malaysiensis. The mites were maintained in a culture medium at 25ºC and 75% relative humidity. Mites were harvested either with heat escape or floatation method, purified, homogenized, quantified and used for the production of polyclonal antibody and immunostaining. For each species of mites, five male mice and five male rats were randomly selected and immunized intraperitoneally with respective crude mite extract at two-weekly intervals. Blomia tropicalis, A. ovatus or G. malaysiensis whole mites and paraffin-embedded mite sections were immunostained with the respective polyclonal antibody. The faecal pellets of mites were intensely stained for all the three species in the present study. The legs of sectioned A. ovatus were not immunogenic as compared with those of G. malaysiensis and B. tropicalis. The outer layer (cuticle) of whole mites and the eggs for these species were very immunogenic. Hence, the polyclonal antibodies obtained in this study may serve as potential tools in detecting the eggs and immature mites in environmental samples. Future studies should focus on the antigenic components of eggs since they were relatively abundant in dust and highly antigenic as seen in the present study.

New mechanical disruption method for extraction of whole cell protein from Candida albicans.

Cell disruption or lysis is a crucial step to obtain cellular components for various biological studies. We subjected different concentrations of Candida albicans to 5, 10, 15 and 20 cycles of disruption. The degree of cell lysis was observed using light microscopy and the yields obtained were measured and analysed. The optimum extraction with 1 x 10(10) yeast cells/ml was achieved after 5 cycles of disruption with 1.0 mm diameter glass beads at 5,000 rpm. Approximately 80% of the cells were lysed and the protein yield was 6,000 microg/ml. SDS-PAGE analysis revealed approximately 25 distinct protein bands with molecular weights ranging from 8 kDa to 220 kDa. We conclude that this mechanical disruption of fungal cells is a rapid, efficient and inexpensive technique for extracting whole cell proteins from yeast cells.