Diadora aspera is an intertidal keyhole limpet found in the mid-tidal zone. Its activity pattern was estimated under laboratory conditions using time-lapse-photography and manometric determinations of oxygen consumption. Statistical and computer analyses of the photographic data suggest the presence of both a 24 hour and a 12-13 hour rhythm in activity. Both oxygen consumption and photographic data suggest that the diel rhythm has an activity peak at noon. The oxygen consumption data also suggest that the 12-13 hour rhythm in activity is peaked 3-4 hours before high tide. Protection from predation (possibly by Pycnopodia helianthoides) is suggested as a possible factor in selection for this phasing. / Graduation date: 1975

Submitted by (edna.saturno@ufrpe.br) on 2017-02-10T12:37:27Z No. of bitstreams: 1 Elizangela Maria de Souza.pdf: 678116 bytes, checksum: 59d0516089dfeb649af279bd353a7fee (MD5) / Made available in DSpace on 2017-02-10T12:37:27Z (GMT). No. of bitstreams: 1 Elizangela Maria de Souza.pdf: 678116 bytes, checksum: 59d0516089dfeb649af279bd353a7fee (MD5) Previous issue date: 2006-04-10 / Aiming to investigate the population and reproductive biology of the “black scale fish” Rhinelepis aspera Spix & Agassiz, 1829, studies have been carried through in a section of the Submiddle São Francisco River Valley , next to the city of Petrolina-PE, located 09º 09' of South Latitude and 40º 22" West of Longitud. Two hundred forty eight specimens were catched by net and mesh (meshes from 8 to 14 cm) in the period of February of 2005 to January of 2006. For each individual was determined sex, total length (Tl-cm), total weight (Tw-g) and gonadal weight (Gw-g). The morfometric description was effected to characterize them macroscopically, defining the GSI (Gonadossomatic Index). Microscopic characterizations had been made to describe the histological aspects of the ovaries and the testicles. The stages of gonadal development were described and a scale of maturity was established (1 - rest, 2 - initial maturation, 3 – mature or advanced maturation and 4 - disposed or spawned) in function of the histological characteristics. During the period collect there was a slight predominance of females (56,4%). The females were more numerous in the classes of bigger lengths and had reached the length of the first maturation (L50) about 41 cm. Themales had reached the length of the first maturation (L50) about 41,5 cm. From 50,5 cm all individuals, males and females, are apt to participate in the reproductive process (L100). It was obtained for all the population of R. aspera the value of angular coefficient (q ≅ 3. 0), as to the relation total weight/ total length, the growth is an isometric type. The GSI presented greater values in the months of February and December 2005 for females and in the months of April 2005 and January 2006 for males. / Visando investigar a biologia reprodutiva do cascudo-preto Rhinelepis aspera Spix & Agassiz, 1829, estudos foram realizados num trecho do submédio do rio São Francisco, próximo à cidade de Petrolina-PE (09º 09’ de Latitude Sul e 40º 22’ de Longitude Oeste). Foram capturados por meio de tarrafa e rede de espera (malhas de 8 a 14 cm entre nós) 248 exemplares no período de fevereiro de 2005 a janeiro de 2006. Para cada indivíduo foi determinado o sexo, comprimento total (Ct-cm), peso total (Pt-g) e peso gonadal (Pg-g). A descrição morfométrica foi efetuada para caracterizá-las macroscopicamente, definindo o IGS (índice gonadossomático). Caracterizações microscópicas foram feitas para descrever os aspectos histológicos dos ovários e dos testículos. Os estágios de desenvolvimento gonadal foram descritos sendo estabelecida uma escala de maturidade (1 – repouso, 2 – maturação inicial, 3 – maturação avançada/ maduro e 4 – desovado ou espermiado) em função das características histológicas. Durante o período de coleta houve ligeira predominância de fêmeas (56,4%). As fêmeas foram mais numerosas nas classes de maiores comprimentos e atingiram o comprimento da primeira maturação (L50) com cerca de 41cm. Os machos atingiram o comprimento da primeira maturação (L50) com cerca de 41,5 cm. A partir de 50,5cm todos os indivíduos machos e fêmeas estão aptos a participar do processo reprodutivo (L100). Obteve-se para toda população de R. aspera o valor do coeficiente angular (q ≅ 3.0), conforme a relação peso total/ comprimento total, cujo crescimento é do tipo isométrico. O IGS apresentou maiores valores nos meses de fevereiro e dezembro de 2005 para fêmeas e nos meses de abril de 2005 e janeiro de 2006 para machos.

Vermeersiekte or ‘vomiting disease’ is an economically important disease of ruminants following ingestion of Geigeria species in South Africa. Sheep are more susceptible and poisoning is characterised by stiffness, regurgitation, bloat, paresis and paralysis. Geigeria aspera was collected in the Vrede district (27° 25′ 48″ S; 29° 9′ 36″ E), Free State Province. The plant material was dried, milled and the toxic principles, known as sesquiterpene lactones, were extracted and isolated following chromatographic procedures. Even though geigerin and ivalin were previously isolated, an unknown sesquiterpene lactone, isogeigerin acetate, was also purified. Mouse myoblast (C2C12) and rat embryonic cardiac myocyte (H9c2) cell lines were exposed to different concentrations of geigerin, ivalin, isogeigerin acetate and a commercially available sesquiterpene lactone, parthenolide. An in vitro colorimetric assay 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) was used to assess cytotoxicity. The median effective concentrations (EC50) indicated that ivalin and parthenolide were significantly (p<0.05) more toxic than geigerin and isogeigerin acetate. A concentration-dependent cytotoxic response was observed in both cell lines, however, C2C12 cells were more sensitive. A high performance liquid chromatography (HPLC) analysis was used to evaluate the in vitro metabolism of parthenolide, following the addition of a mouse liver microsomal fraction. Results revealed that parthenolide, incubated with the microsomal fraction, undergoes enzymatic transformation to form a metabolite. / Dissertation (MSc (Veterinary Sciences))--University of Pretoria, 2020. / pt2021 / Paraclinical Sciences / MSc (Veterinary Sciences) / Unrestricted