ABSTRACT
The complete mitochondrial genome of the whitetip reef shark Triaenodon obesus is determined in this study. It is 16,700 bp in length, with the typical gene composition, arrangement and transcriptional orientation in vertebrates. The overall base composition is 31.4% A, 25.8% C, 13.2% G and 29.7% T. Two start codons and two stop codons are found in the protein-coding genes. The 22 tRNA genes ranged from 67 to 75 nucleotides. The tRNA-Ser2 lost the DHU arm and could not be folded to the typical cloverleaf secondary structure. The origin of L-strand replication (OL) sequence was identified between tRNA-Asn and tRNA-Cys genes. The high A+T content of control region is due to a lot of poly A and poly T.
Subject(s)
Elasmobranchii/genetics , Genome, Mitochondrial/genetics , Sharks/genetics , Animals , Base Composition/genetics , Codon, Initiator/genetics , Codon, Terminator/genetics , RNA, Transfer, Asn/genetics , Sequence Analysis, DNA/methodsABSTRACT
In Western literature, there is evidence that museum explainers offer significant potential for enhancing visitors' learning through influencing their knowledge, content, action, behaviour and attitudes. However, little research has focused on the role of explainers in other cultural contexts. This study explored interactions between visitors and museum explainers within the setting of Thailand. Two questionnaires were distributed to 600 visitors and 41 museum explainers. The results demonstrated both potential similarities and differences with Western contexts. Explainers appeared to prefer didactic approaches, focussing on factual knowledge rather than encouraging deep learning. Two-way communication, however, appeared to be enhanced by the use of a 'pseudo-sibling relationship' by explainers. Traditional Thai social reserve was reduced through such approaches, with visitors taking on active learning roles. These findings have implications for training museum explainers in non-Western cultures, as well as museum communication practice more generally.
Subject(s)
Attitude , Museums , Science/education , Adolescent , Adult , Child , Female , Humans , Male , Surveys and Questionnaires , Thailand , Young AdultABSTRACT
Clionasterol (1a), clionasterol monoacetate (1b) and 5alpha,8alpha-epidioxy-24alpha-ethylcholest-6-en-3-ol (2), isolated from the marine sponge Xestospongia exigua, and beta-sitosterol (3) were tested for their influence on the classical (CP) and alternative (AP) pathways of activation of the human complement system in vitro. All the sterols inhibited the CP in a dose-dependent manner but no detectable effect was observed in the AP even at concentrations of 400 microM. Clionasterol was found to be a potent inhibitor of CP (IC50 = 4.1 microM) being ten-fold more active than beta-sitosterol. The presence of the epidioxy group on C-5 and C-8 of compound 2 caused a pronounced decrease of the inhibitory effect. Mechanistic studies on the anticomplementary effect of clionasterol revealed that it interferes with the complement component C1.
Subject(s)
Complement Inactivator Proteins/pharmacology , Porifera , Sitosterols/pharmacology , Animals , Complement Inactivator Proteins/administration & dosage , Complement Inactivator Proteins/therapeutic use , Complement Pathway, Alternative/drug effects , Complement Pathway, Classical/drug effects , Dose-Response Relationship, Drug , Hemolysis/drug effects , Humans , Inhibitory Concentration 50 , Sitosterols/administration & dosage , Sitosterols/therapeutic useABSTRACT
Reexamination of the marine sponge Suberea aff. praetensa, (Row) from the Gulf of Thailand furnished in addition to bromotyrosine derivatives found previously 5-bromo- and 5-chlorocavernicolin, cavernicolins 1 and 2, two other brominated tyrosine metabolites, a known bisoxazolidone and a new unusual rearranged tyrosine metabolite subereatensin. Several of the metabolites exhibited significant inhibitory effects against five human cancer cell lines.
