The presence of paralytic shellfish poisoning (PSP) toxins in cultures of Aphanizomenon flos-aquae, isolated from the Crestuma-Lever reservoir, was found by reversed phase high performance liquid chromatography employing two isocratic elution systems for the separation of PSP toxins. With the first isocratic elution protocol, the presence of apolar toxins as saxitoxin, decarbamoyl saxitoxin and neosaxitoxin not detected. On the other hand, GTX4, GTX1 and GTX3 as well as Cs toxins were present either in the Aphanizomenon flos-aquae cells collected directly from the bloom or in the other toxic isolates priorly cultivated in laboratory conditions.
The life cycle of the red swamp cray sh, Procambarus clarkii from a shallow lagoon in the Aveiro region was studied for 14 months. Analysis of the size frequency distribution and growth provided evidence for an extended recruitment period with a peak in autumn (October/November). Females clearly outnumbered males and the average sex-ratio (males/females) was 0.36. The values for the Von Bertalanffy growth parameters were L 1 D 62:01 mm, K D 0.23, and t 0 D 0:11 month. The high abundance of this species and the extended recruitment period, support the need for a proper management and exploitation of this biological resource. RESUMO O ciclo de vida do lagostim-vermelho-da-Louisiana Procambarus clarkii da ria de Aveiro foi estudado ao longo de 14 meses. A análise da distribuição das frequências de tamanho e de crescimento mostrou um período de recrutamento extenso com um máximo no Outono (Outubro/Novembro). As fêmeas ocorreram com maior abundância que os machos, o que se traduziu numa proporção de sexos (machos/fêmeas) de 0,36. Os valores calculados para os parâmetros de crescimento de Von Bertalanffy foram L 1 D 62,01 mm, K D 0,23 e t 0 D 0,11 mês. A elevada abundância desta espécie e o largo período de recrutamento apontam para a necessidade de uma adequada gestão e exploração deste recurso biológico.
Bjirrkman lignin, obtained by extensive grinding and dioxane extraction, is considered one of the most suitable standard preparations close to the native lignin from lignocellulosic materials. In this study, alkalilipin extracted with 1 M NaOH at 30°C (AL-1M30C), and the BjBrkman lignin from wheat straw (IhXcum aesfivum) were compared using spectroscopic and degradative techniques. The very small chemical differences between the two preparations are mainly that the Bjirrkman method yields a lignin with slightly higher proportion of phydroxyphenyl units, and some co-extracted aliphatic fractions. The AL-lM30C preparation, on the other hand, showed a somewhat higher proportion of syringyl units, as well as the probable effects of the selective removal of structures assoCiated with ester carbonyl groups. The evident similarity between both lignin samples suggests that AL-lMSC produced from wheat straw may represent a convenient alternative to BjBrkman lignin preparation for analytical purposes. These results also point towards the possibility of producing suitable lignin preparations from other Gramineae plants showing high solubility in alkaline reagents.
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