Sub-lethal Camphor Exposure Triggers Oxidative Stress, Cardiotoxicity, and Cardiac Physiology Alterations in Zebrafish Embryos.

Camphor is a terpene ketone with aromatic and volatile properties in nature derived from the bark of Cinnamomum camphora or synthesized from turpentine. Camphor exhibits various biological properties such as anti-microbial, anti-viral, anti-coccidial, and anti-cancer. It is also used as a form of topical medication for skin irritation, joint pain, and as a relief for itching from insect bites. However, even though the high dose of camphor has been documented to be toxic/lethal in humans in different studies, camphor's developmental toxicity has not yet been explored, and its extensive mechanism of action is still unclear. In the present study, we aimed to assess the toxic effects of camphor in zebrafish embryos in the initial developmental stages. The obtained results demonstrated that a sub-lethal dose of camphor caused a decrease in hatching rate, body length, and substantial elevation in malformation rate on zebrafish embryos. On further observation, in the following time frame, curved body and pericardial edema of zebrafish were also observed. Furthermore, exposure to a sub-lethal dose of camphor was also able to trigger cardiotoxicity in zebrafish larvae. Later, on subsequent biochemical analysis, it was found that the antioxidant capacity inhibition and oxidative stress elevation that occurred after camphor exposure might be associated with the inhibition of total superoxide dismutase (SOD) activity and an increase in reactive oxygen species (ROS) and malondialdehyde (MDA) concentration. In addition, compared to the control group, several apoptotic cells in treated zebrafish were also found to be elevated. Finally, after further investigation on marker gene expressions, we conclude that the developmental toxicity of camphor exposure might be associated with apoptosis elevation and oxidative stress. Taken together, the current study provides a better understanding of the developmental toxicity of camphor on zebrafish, a promising alternative animal model to assess the developmental toxicity of chemical compounds.

Gemmobacter lanyuensis sp. nov., isolated from a freshwater spring.

A bacterial strain designated Orc-4(T) was isolated from a freshwater spring in Taiwan and characterized using the polyphasic taxonomic approach. Cells of strain Orc-4(T) were facultatively anaerobic, Gram-reaction-negative, poly-ß-hydroxybutyrate-accumulating, non-motile rods surrounded by a thick capsule and forming cream-white colonies. Growth occurred at 15-40 °C (optimum, 25-30 °C), at pH 6.0-9.0 (optimum, pH 7.0) and with 0-1 % NaCl (optimum, 0-0.5 %). Phylogenetic analyses based on 16S rRNA gene sequences showed that strain Orc-4(T) belonged to the genus Gemmobacter within the family Rhodobacteraceae of the class Alphaproteobacteria and its most closely related neighbour was Gemmobacter fontiphilus JS43(T) with sequence similarity of 97.8 %. Strain Orc-4(T) contained C18 : 1ω7c as the predominant fatty acid. The major respiratory quinone was Q-10. The DNA G+C content of the genomic DNA was 63.5 mol%. The polar lipid profile consisted of a mixture of phosphatidylglycerol, phosphatidylethanolamine, phosphatidylcholine, one uncharacterized aminolipid and several uncharacterized phospholipids. The DNA-DNA relatedness of strain Orc-4(T) with respect to recognized species of the genus Gemmobacter was less than 48 %. On the basis of the genotypic, chemotaxonomic and phenotypic data, strain Orc-4(T) represents a novel species of the genus Gemmobacter, for which the name Gemmobacter lanyuensis sp. nov. is proposed. The type strain is Orc-4(T) ( = BCRC 80378(T) = LMG 26667(T) = KCTC 23714(T)).

Sphingobium fontiphilum sp. nov., isolated from a freshwater spring.

To investigate the biodiversity of bacteria in the spring water of the Chengcing Lake Park in Taiwan, a Gram-stain-negative, rod-shaped, non-motile, non-spore-forming and aerobic bacterial strain, designated strain Chen16-4(T), was isolated and characterized in a taxonomic study using a polyphasic approach. Phylogenetic analyses based on 16S rRNA gene sequences showed that the closest relatives of strain Chen16-4(T) were Sphingobium amiense YT(T), Sphingobium yanoikuyae GIFU 9882(T) and Sphingobium scionense WP01(T), with sequence similarities of 97.6, 97.1 and 97.0 %, respectively. A phylogenetic tree obtained with 16S rRNA gene sequences indicated that strain Chen16-4(T) and these three closest relatives formed an independent phylogenetic clade within the genus Sphingobium. The polar lipid pattern, the presence of spermidine and ubiquinone Q-10, the predominance of C18 : 1ω7c in the cellular fatty acid profile and the DNA G+C content also supported affiliation of the isolate to the genus Sphingobium. The DNA-DNA relatedness of strain Chen16-4(T) with respect to recognized species of the genus Sphingobium was less than 70 %. On the basis of the genotypic, chemotaxonomic and phenotypic data, strain Chen16-4(T) represents a novel species in the genus Sphingobium, for which the name Sphingobium fontiphilum sp. nov. is proposed. The type strain is Chen16-4(T) ( = BCRC 80308(T) = LMG 26342(T) = KCTC 23559(T)).