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Genetic Stock Identification of the Flathead Grey Mullet (Mugil cephalus) in Lake Tiberias Based on ParentOffspring Relationship
Get PDFThe Lake Tiberias (Sea of Galilee) grey mullet (Mugil cephalus) population originates from translocated wild-caught, or hatchery-reared, fish. The aim of the study was to identify the taxonomic status and stock origin of a sample of 32 mullet individuals caught in the Sea of Galilee, based on the mitochondrial Cytochrome Oxidase I (COI) sequence analysis and nuclear microsatellite markers. A total of 13 microsatellite markers were selected from nine different linkage groups with a number of alleles ranging from 5-23, with an average of 9.85 alleles/locus. By using COI sequences and the Barcode of Life Data (BOLD) identification system, seven individuals were taxonomically classified as Thinlip grey mullet (Liza ramda) and the remaining 25 as M. cephalus. Of 663 nucleotides, 122 (18.4%) differed between the COI sequences of the two distinct mullet species. A preliminary parentage analysis of the hatchery-reared stocking batch, based on 13 markers, assigned them as progeny of three mating pairs. These three mating pairs only were tested as potential parents of the 25 M. cephalus individuals captured from the lake. Marker-based comparison showed that a parent-offspring relationship was rejected for 17 M. cephalus individuals by at least four genetic markers. Eight of 25 M. cephalus individuals (32%), were identified as progeny of the three parental pairs with the overall probability of 3.88 x 10-7 for correspondence by chance to any of these three parental pairs. The 13 markers used has high statistical power to reject a putative parent-offspring relationship obtained by chance thus resulting in familial identification. This approach represents an accurate method of genetic stock identification and should also be applicable to populations of other species. The results confirm that the mullet hatcheryreared fingerlings survived in the Sea of Galilee when released alongside wildcaught fingerlings
Molecular Cloning of Twist Gene and its Expression in Golden Pompano Trachinotus ovatus (Linnaeus 1758) Larvae at Different Water Temperatures
Get PDFThe twist gene in golden pompano Trachinotus ovatus larvae was cloned and analyzed in this study. in the first 18 days the expression of twist during larval fish ontogeny was explored, then on 18 day post hatch (DPH) the expression of twist in fish tissues was evaluated. Subsequently, the response of twist to water temperatures of 23, 26, and 29oC was compared on 12 DPH and 18 DPH. The cDNA sequence length of the twist gene in golden pompano is 880 bp with an open reading frame of 507 bp. The twist gene encodes 168 amino acids and has a calculated molecular weight of 18.93 kDa and a theoretical isoelectric point of 9.14. After hatching, the expression of twist increased with fish age, and peaked at 3 and 4 DPH. The highest expression of twist in fish tissue occurred in the spleen and stomach, followed by the brain and kidney on 18 DPH. On 12 DPH, the highest expression of twist was observed in fish reared at 26oC, and lowest expression was observed in fish reared at 29oC. On 18 DPH, the expression of twist was not significantly affected by the rearing temperatures. This study identified the gene expression of twist at the early developmental stage of golden pompano; the time dependent expression of twist in fish larvae may improve knowledge of bone ontogeny and formation in fish larvae
Two Rapid Methods to Identify Three Species of Pathogenic Vibrio in Penaeus vannamei
Get PDFVibrio species frequently infect Penaeus vannamei causing great economic losses to the
Whiteleg shrimp industry. Rapid detection of pathogenic Vibrio infection would improve
the fight against these diseases. In this study, single and multiple polymerase chain
reaction (PCR) methods were developed to detect three species of pathogenic Vibrio:
Vibrio fluvialis, Vibrio anguillarum, and Vibrio alginolyticus. Specific primers were
designed for the toxR gene of V. fluvialis, the flaA gene of V. anguillarum, and the pyrH
gene of V. alginolyticus. The bacteria were used as templates to establish a 25 μL
reaction system for PCR amplification. The results showed that single and specific PCR
amplification products of expected sizes were obtained (228bp, 1665bp, and 383bp,
respectively). The lowest concentration detected for the three Vibrio species were
5.21×102
, 2.70×104
, and 2.48×102 colony forming units (cfu)/mL, respectively. We also
developed a multiplex PCR method to identify the three Vibrio species accurately, and
with improved identification efficiency. In addition, quantitative real-time PCR (qPCR)
was used to identify the minimum detectable DNA concentration for the three Vibrio
species (1.0×10-6 nmol/L for V. fluvialis, 1.0×10-7 nmol/L for V. anguillarum, and 1.0×10-
8 nmol/L for V. alginolyticus). Technical requirements for ordinary PCR are low, therefore
PCR is a feasible technique to detect and diagnose Penaeus vannamei bacterial disease
Identification and mRNA Expression of Heat Shock Proteins in the Mud Crab (Scylla paramamosain) in Response to Acute Nitrite Exposure
Get PDFHeat shock proteins (HSPs) play an important role in protecting organisms against various stressors. Heat shock protein 40 (HSP40) is a class of the heat shock protein family and performs a function as co-chaperone of HSP70. In this study, an HSP40 gene from the mud crab Scylla paramamosain (SpHSP40) was identified and characterized. The full-length cDNA of SpHSP40 was 1904 bp, containing an open reading frame (ORF) of 1191 bp, a 5´UTR of 118 bp, and a 3´UTR of 595 bp. The deduced amino acid sequence of SpHSP40 contained all four classical HSP40 family signatures. Quantitative real-time PCR analysis revealed that SpHSP40 transcript was expressed in a wide range of tissues, while strong expression was observed in the hepatopancreas. In order to understand the response of heat shock proteins induced by nitrite exposure, expression levels of HSPs (SpHSP90, SpHSP70, SpHSP60 and SpHSP40) mRNA in the hepatopancreas and gills were investigated. Results show that HSPs (SpHSP90, SpHSP70, SpHSP60 and SpHSP40) were up-regulated displaying a time-dependent pattern in response to nitrite stress. All these results indicate that HSPs play an important role in mediating environmental stress in mud crabs
Papers from the Chulalongkorn International Student Symposium on Southeast Asian Linguistics 2017
Get PDFThis is a collection of 19 articles from the Chulalongkorn International Student Symposium on Southeast Asian Linguistics held in 2017. The papers cover a full range of linguistic topics (phonetics/phonology, morphosyntax, historical and ethno-linguistics, etc.) regarding languages in most of the language families of Greater Mainland Southeast Asia
Rhetorical Questions in Papuan Malay, Other Malayic Languages, and the Papuan Languages of West Papua
Get PDFThis paper presents a descriptive and typological study of rhetorical questions. The first part describes the form and functions of rhetorical questions in Papuan Malay. There are no formal characteristics that mark Papuan Malay rhetorical questions. Instead, the context indicates whether a question has rhetorical functions. Typically, Papuan Malay rhetorical questions have social functions as pseudo questions, while their discourse-stimulating uses as stimulus questions are marginal. Pseudo questions are used to convey assertions, expressions of incertitude and negative evaluations. The speakersﾒ underlying emotions tend to be negative. The second part of this paper investigates typological aspects of rhetorical questions in Malayic languages, as well as other Austronesian and Papuan languages in West Papua. Three patterns emerge which are submitted as testable hypotheses for further studies on rhetorical questions: (1) rhetorical questions tend to have social functions; (2) speakers do not use them to convey positive evaluations; and (3) rhetorical questions tend to carry underlying negative emotions. For Papuan Malay, at least, all three patterns apply
Effects of Dietary Surfactin Supplementation on Growth Performance, Intestinal Digestive Enzymes Activities, and Hepatic Antioxidant Potential of American Eel (Anguilla rostrata) Elvers
Get PDFThe 70-day trial was conducted to investigate the effects of surfactin on growth performance, intestinal digestive enzymes activities, and hepatic antioxidant potential on American eel (Anguilla rostrata) at elver stage. Six hundred American eel elvers were randomly divided into five treatments with three replicates per group, 40 fish per replicate. Dietary surfactin levels of the five treatment groups were 0, 25, 50, 100, and 200 mg/kg, respectively. Final body weight, weight gain rate, and feed efficiency were significantly affected by surfactin supplementation (P0.05). Protease and lipase activity in the intestine were significantly increased by surfactin supplementation (P0.05). Malondialdehyde level, total antioxidation capacity level, and activities of superoxide dismutase, and glutathione peroxidase in intestine of fish were significantly (P0.05). The results demonstrated that dietary 25 mg/kg surfactin supplementation improves growth performance, some digestive enzyme activities in the intestine, and hepatic antioxidant potential of American eel at elver stage
