ALBERT

Beschreibung: Mechanisms that affect thermal tolerance of ectothermic organisms have recently received much interest, mainly due to global warming and climate-change debates in both the public and in the scientific community. In physiological terms, thermal tolerance of several marine ectothermic taxa can be linked to oxygen availability, with capacity limitations in ventilatory and circulatory systems contributing to oxygen limitation at extreme temperatures. The present review briefly summarizes the processes that define thermal tolerance in a model cephalopod organism, the cuttlefish Sepia officinalis, with a focus on the contribution of the cephalopod oxygen-carrying blood pigment, hemocyanin. When acutely exposed to either extremely high or low temperatures, cuttlefish display a gradual transition to an anaerobic mode of energy production in key muscle tissues once critical temperatures (Tcrit) are reached. At high temperatures, stagnating metabolic rates and a developing hypoxemia can be correlated with a progressive failure of the circulatory system, well before Tcrit is reached. However, at low temperatures, declining metabolic rates cannot be related to ventilatory or circulatory failure. Rather, we propose a role for hemocyanin functional characteristics as a major limiting factor preventing proper tissue oxygenation. Using information on the oxygen binding characteristics of cephalopod hemocyanins, we argue that high oxygen affinities (= low P50 values), as found at low temperatures, allow efficient oxygen shuttling only at very low venous oxygen partial pressures. Low venous PO2s limit rates of oxygen diffusion into cells, thus eventually causing the observed transition to anaerobic metabolism. On the basis of existing blood physiological, molecular, and crystallographical data, the potential to resolve the role of hemocyanin isoforms in thermal adaptation by an integrated molecular physiological approach is discussed.

Beschreibung: The functional response of Sepia officinalis early stages, preying on mysids of the species Mesopodopsis slabberi was investigated. The effects of five prey densities (12.5, 25, 37.5, 50 and 125 mysids l−1) and two hatchling ages (1-day-old and 7-day-old) on consumption rate and the frequency of non-feeding animals were tested. Older animals were approximately 50% heavier than newly hatched ones. Hatchlings were individually assayed under 0.25 W m−2 natural light, 37.8 psu in salinity and 19°C. The effect of prey density on consumption rate was highly significant and no effect of age was detected within the age range tested. Maximal values recorded for consumption rate were about 0.45 mysids h−1. The frequency of non-feeding individuals was strongly reduced at saturating prey densities. The functional response curve showed an interval of prey densities for which density-dependent prey mortality is probable.

Beschreibung: Recent molecular studies investigating higher-level phylogenetics of coleoid cephalopods (octopuses, squids and cuttlefishes) have produced conflicting results. A wide range of sequence alignment and analysis methods are used in cephalopod phylogenetic studies. The present study investigated the effect of commonly used alignment and analysis methods on higher-level cephalopod phylogenetics. Two sequence homology methods: (1) eye alignment, (2) implied alignment, and three analysis methods: (1) parsimony, (2) maximum likelihood, (3) Bayesian methodologies, were employed on the longest sequence dataset available for the coleoid cephalopods, comprising three mitochondrial and six nuclear loci. The data were also tested for base composition heterogeneity, which was detected in three genes and resolved using RY coding. The Octopoda, Argonautoidea, Oegopsida and Ommastrephidae are monophyletic in the phylogenies resulting from each of the alignment and analysis combinations. Furthermore, the Bathyteuthidae are the sister taxon of the Oegopsida in each case. However many relationships within the Coleoidea differed depending upon the alignment and analysis method used. This study demonstrates how differences in alignment and analysis methods commonly used in cephalopod phylogenetics can lead to different, but often highly supported, relationships.

Beschreibung: We report data on the stomach contents of the long‐finned pilot whale, Globicephala melas, recovered from a group of whales stranded on Ruakaka Beach, northeastern New Zealand, in November 2006. In nine whales for which identifiable stomach contents were recovered (three that stranded on 10 November and six that stranded on 11 November) prey remains comprised exclusively cephalopod beaks attributed to five squid species. The stomachs of a further two whales contained unidentifiable upper beaks only, while the stomachs of five whales were completely empty. No whale appeared to have been satiated immediately before stranding, given that the maximum biomass of prey recently consumed by any one whale was calculated to be 〈5 kg. All squids ingested represented oceanic species, found from 50 to 1000 m but more common towards the deeper end of this range. These data both complement and contrast with the only other dietary information available for this species in New Zealand waters, reported from stomach contents of whales stranded on Farewell Spit, South Island in December 2005.

Beschreibung: Stomach contents of the long‐finned pilot whale, Globicephala melas, are reported for the first time from New Zealand waters. Analyses based on two male and three female whales (2.5–5.3 m in length) that stranded on Farewell Spit, Golden Bay, South Island in December 2005 revealed a diet comprised exclusively of cephalopods (2-33 lower cephalopod beaks per stomach). Two genera of cephalopod from two orders; arrow squid, Nototodarus spp. (Teuthoidea: Ommastrephidae), and common octopus, Pinnoctopus cordiformis (Octopoda: Octopodidae) were represented. A further five pilot whale stomachs were examined and found to be empty.

Beschreibung: Microbial isolate Z143-1 found to be associated with an unidentified tunicate was characterized due to its significant antimicrobial activity. Z143-1 is similar to Pseudovibrio ascidiaceicola and Pseudovibrio denitrificans in morphological, physiological and biochemical characteristics, except for its ability to ferment glucose and produce a characteristic red pigment. Fatty acid methyl ester analysis revealed a predominance of the fatty acid 18:1 ω7c at 80.55%, at levels slightly lower than the Pseudovibrio denitrificans type strain DN34T (87.7%). The mol% G+C of Z143-1 is 54.02, relatively higher than the Pseudovibrio denitrificans type strain DN34T and Pseudovibrio ascidiaceicola with mol% G+C of 51.7 and 51.4, respectively. However, phylogenetic analysis of the 16S rRNA gene sequence of Z143-1 showed 100% similarity with the Pseudovibrio denitrificans type strain DN34T. In this study, the bacterium Z143-1 is reported as a new strain of Pseudovibrio denitrificans. While there is no report of a secondary metabolite for Pseudovibrio denitrificans, Z143-1 produces the red pigment heptylprodigiosin, also known as 16-methyl-15-heptyl-prodiginine, which shows anti-Staphylococcus aureus activity.

Beschreibung: Diosmetin, 5,7,3′-trihydroxy-4′-methoxyflavone shows chemopreventive, antimutagenic, and antiallergic effects. On the other hand, chrysoeriol, 5,7,4′-trihydroxy-3′-methoxyflavone induced nodABC-lacZ in Rhizobium meliloti. Both of them belong to hydroxymethoxy- flavones. One major difference between diosmetin and chrysoeriol is the substituted position of hydroxyl and methoxyl groups. In order to elucidate the relationships between their structures and activity, one of the first things to be done is the determination of their structures. However, most flavones occur widely in nature, and thus it is difficult to obtain in sufficient amounts from natural sources to identify their structures. Assignments of NMR data of several hydroxymethoxyflavones may help us to identify novel flavonoid compounds isolated from natural sources based on their NMR experiments. Therefore, we report here the complete assignments of 1H and 13C NMR data of 13 hydroxymethoxyflavones.

Beschreibung: Meiobenthos densities and higher taxon composition were studied in an active gas seepage area at depths from 182 to 252 m in the submarine Dnieper Canyon located in the northwestern part of the Black Sea. The meiobenthos was represented by Ciliata, Foraminifera, Nematoda, Polychaeta, Bivalvia, Gastropoda, Amphipoda, and Acarina. Also present in the sediment samples were juvenile stages of Copepoda and Cladocera which may be of planktonic origin. Nematoda and Foraminifera were the dominant groups. The abundance of the meiobenthos varied between 2397 and 52,593 ind.·m−2. Maximum densities of Nematoda and Foraminifera were recorded in the upper sediment layer of a permanent H2S zone at depths from 220 to 250 m. This dense concentration of meiobenthos was found in an area where intense methane seeps were covered by methane-oxidizing microbial mats. Results suggest that methane and its microbial oxidation products are the factors responsible for the presence of a highly sulfidic and biologically productive zone characterized by specially adapted benthic groups. At the same time, an inverse correlation was found between meiofauna densities and methane concentrations in the uppermost sediment layers. The hypothesis is that the concentration of Nematoda and Foraminifera within the areas enriched with methane is an ecological compromise between the food requirements of these organisms and their adaptations to the toxic H2S.