Rare orchid species in Malaysia: New records, recollections and amended descriptions.

Paphiopedilum exul, Calanthe chrysoglossoides, and Luisia brachystachys are reported here as new records for Malaysia, whereas Bryobium cordiferum subsp. borneense, Habenaria rostellifera, and Taeniophyllum rugulosum are three rare orchid species recollected from Sarawak, Perlis, and Perak, respectively. This paper highlights brief descriptions and photographic illustrations of each species for easy identification. Besides, notes on morphological comparisons with the closely related species and artificial taxonomic keys are included as well.

Determination of Phenolics and Flavonoids of Some Useful Medicinal Plants and Bioassay-Guided Fractionation Substances of Sclerocarya birrea (A. Rich) Hochst Stem (Bark) Extract and Their Efficacy Against Salmonella typhi.

Gallic acid and catechin are the most abundant phenolic and flavonoid contents found in all plant extracts. The contents and the bioassay-guided fractionating substances of the Sclerocarya birrea (A. Rich) Hochst (Anacardiaceae) fraction played vital roles. The goals of the study were to determine the contents of some useful medicinal plants and the bioassay-guided fractionation substances of S. birrea fraction compounds capable of acting against Salmonella isolate using LC-MS/LC-HRMS (Dionex ultimate 3000 RS UPLC with Thermo Scientific Q Exactive Orbitrap Hybrid Tandem Mass Spectrometer). The Folin-Ciocalteu reagent procedure and flavonoid content determination were conducted spectrophotometrically. Bioassay-guided fractionation, chronological partitioning, and screening of the antibacterial action against Salmonella typhi were performed. The ethyl acetate fraction extracts of S. birrea stem (bark) extract were analyzed using LC-MS/LC-HRMS. The gallic acid content increased tremendously in Vachellia nilotica (L.) P.J.H. Hurter and Mabb (Fabaceae) pod extracts with curve fitting (R 2 = 0.9958). Catechin content increase was significantly increased in S. birrea stem (bark) extracts followed by that of V. nilotica pod extracts with curve fitting (R 2 = 0.9993); they were all significantly different in the Guiera senegalensis J.F. Gmel. and the Leptadenia lanceolata (Poir.) Goyder leaves extracts at p value <0.0001. Subsequently, 10 mg/ml of S. birrea stem (bark) ethyl acetate fraction extract was the MIC, where no MBC was recorded and susceptible to the positive control with the highest inhibition zone, followed by the ethyl acetate fraction extract at 10 mg/ml (9.7 ± 0.0) at Turkey's p < 0.0001. Vidarabine is one of the novel compounds, specifically having antimicrobial actions, found in the S. birrea stem (bark). Reasonable amounts of phenolic and flavonoid contents determined the actions of the individual plant extract.

Virulence-associated genes and antibiotic resistance patterns of Vibrio spp. isolated from cultured marine fishes in Malaysia.

BACKGROUND: Vibriosis is an important bacterial disease of cultured marine fishes worldwide. However, information on the virulence and antibiotic resistance of Vibrio spp. isolated from fish are scarce. This study investigates the distribution of virulence associated genes and antibiotic resistance patterns of Vibrio spp. isolated from cage-cultured marine fishes in Malaysia. RESULTS: A total of 63 Vibrio spp. isolated from 62 cultured marine fishes in various geographical regions in Peninsular Malaysia were analysed. Forty-two of the isolates (66.7%) were positive for all chiA, luxR and vhpA, the virulence genes produced by pathogenic V. harveyi. A total of 62 Vibrio isolates (98%) had tlh gene of V. parahaemolyticus, while flaC gene of V. anguillarum was detected in 43 of isolates (68%). Other virulence genes, including tdh, trh, hlyA and toxRvc were absent from any of the isolates. Multiple antibiotic resistance (MAR) was exhibited in all strains of Harveyi clade, particularly against ampicillin, penicillin, polypeptides, cephems and streptomycin. The MAR index ranged between 0.06 and 0.56, and 75% of the isolates have MAR index of higher than 0.20. Host species and geographical origin showed no correlation with the presence of virulence genes and the antibiotic resistance patterns of Vibrio spp. CONCLUSIONS: The study indicates that majority of Vibrio spp. isolated from cultured marine fishes possess virulence genes, but were not associated with human pathogen. However, the antibiotics resistance is a real concern and warrants ongoing surveillance. These findings represent an updated knowledge on the risk of Vibrio spp. to human health, and also provides valuable insight on alternative approaches to combat vibriosis in cultured fish.

Environmental Factors Associated with the Presence of Vibrionaceae in Tropical Cage-Cultured Marine Fishes.

This study investigated the environmental factors associated with the presence of Vibrionaceae in economically important cage-cultured tropical marine fishes: the Asian Seabass Lates calcarifer, snapper Lutjanus sp., and hybrid grouper Epinephelus sp. Fish sampling was conducted at monthly intervals between December 2016 and August 2017. The body weight and length of individual fish were measured, and the skin, eye, liver, and kidney were sampled for bacterial isolation and identification. Water physicochemical parameters during the sampling activities were determined, and the enumeration of total Vibrionaceae count was also conducted from water and sediment samples. Nine species of Vibrio were identified, including V. alginolyticus, V. diabolicus, V. harveyi, V. campbellii, V. parahaemolyticus, V. rotiferianus, V. furnissii, V. fluvialis, and V. vulnificus. Photobacterium damselae subsp. damselae was also identified. A total of 73% of the isolated Vibrio belonged to the Harveyi clade, followed by the Vulnificus clade (5.5%) and Cholera clade (0.6%). Highest occurrence of Vibrio spp. and P. damselae subsp. damselae was found in hybrid grouper (72%), followed by Asian Seabass (48%) and snapper (36%). The associations of Vibrio spp. and P. damselae subsp. damselae with the host fish were not species specific. However, fish mortality and fish size showed strong associations with the presence of some Vibrio spp. On average, 60% of the infected cultured fish exhibited at least one clinical sign. Nevertheless, inconsistent associations were observed between the pathogens and water quality. The yearlong occurrence and abundance of Vibrionaceae in the environmental components indicate that they might serve as reservoirs of these pathogens.

Isolation, characterization, and identification of potential Diuron-degrading bacteria from surface sediments of Port Klang, Malaysia.

Diuron is an alternative biocide suggested to replace organotin in formulating antifouling paints to be applied on water-going vessels hull. However, it is potentially harmful to various non-targeted marine organisms due to its toxic properties. Present study aimed to isolate, screen and identify the potential of Diuron-degrading bacteria collected from the marine sediments of Port Klang, Malaysia. Preliminary screening was conducted by exposing isolated bacteria to 430ng/L (background level), followed by 600ng/L and 1000ng/L of Diuron concentrations. Nine bacteria colonies survived the exposure of the above concentrations. However, only two strains can tolerate to survive up to 1000µg/L, which were then characterised and identified using phenotypic tests and the standard 16S rRNA molecular identification. The strains were identified as Comamonas jiangduensis SZZ 10 and Bacillus aerius SZZ 19 (GenBank accession numbers: KU942479 and KU942480, respectively). Both strains have the potential of Diuron biodegradation for future use.

Rapid biodegradation of polycyclic aromatic hydrocarbons (PAHs) using effective Cronobacter sakazakii MM045 (KT933253).

Polycyclic Aromatic Hydrocarbons (PAHs) are complex and widely distributed environmental pollutants that can affect living ecosystems. This study was conducted to rapidly degrade phenanthrene and pyrene representing low and high molecular weight of PAHs, respectively. Cronobacter sakazakii MM045 (KT933253) was identified from used engine oil of contaminated soil. PAHs biodegradation was carried out using 2,6-dichlorophenol indophenol (DCPIP) assay. Biodegradation influencing factors including agitation, temperature, pH, inoculums volume and salinity were enhanced using Response Surface Methodology (RSM) by Central Composite Design (CCD). Phenanthrene and pyrene biodegrading metabolites were identified using gas chromatography mass spectrophotometer (GCMS). •Initial biodegradation indicated 75.2% and 54.3% phenanthrene and pyrene degraded by C. sakazakii MM045 within 24 h. After CCD optimisation, 100% degradation was achieved for each of the phenanthrene and pyrene, resulting in the formation of intermediate metabolites.•The identified phenanthrene metabolites were 3,4-dihydroxyphenathrene, phthalic acid, pyruvic acid, acetic acid and oxalic acid. Pyrene intermediates comprised pyrene cis-4,5-dihydrodiol, 3,4-dihydroxyphenanthrene, phthalic acid, pyruvic acid, acetic acid and lactic acid.•Cronbacter sakazakii MM045 was proven to be rapid and effective in degrading PAHs within 24 h despite the unavailability of existing literatures on PAHs biodegradation.

Klebsiella sp. FIRD 2, a TBT-resistant bacterium isolated from contaminated surface sediment along Strait of Johor Malaysia.

A possible tributyltin (TBT)-degrading bacterium isolated from contaminated surface sediment was successfully identified as Klebsiella sp. FIRD 2. It was found to be the best isolate capable of resisting TBT at a concentration of 1000 µg L(-1). This was a concentration above the reported contaminated level at the sampling station, 790 µg L(-1). Further studies revealed that the isolate was Gram negative and resisted TBT concentrations of up to 1500 µg L(-1) in a Minimal Salt Broth without the addition of any carbon source within the first 48 h of incubation. It is expected that additional work could be conducted to check the degradation activity of this new isolate and possibly improve the degradation capacity in order to contribute to finding a safe and sustainable remediation solution of TBT contamination.

Bacillus cereus as a biotemplating agent for the synthesis of zinc oxide with raspberry- and plate-like structures.

Currently the development of green chemistry approach with the use of biomaterial-based activities of microbial cells in the synthesis of various nanostructures has attracted a great attention. In this study, we report on the use of bacterium, Bacillus cereus as a biotemplating agent for the formation of zinc oxide nanoparticles with raspberry- and plate-like structures through a simple thermal decomposition of zinc acetate by maintaining the original pH of the reaction mixtures. Possible mechanism on the formation of the nanostructures is proposed based on the surface chemistry and biochemistry processes involved organic-inorganic interactions between zinc oxide and the microbial cells.