Antifouling activity and microbial diversity of two congeneric sponges Callyspongia spp. from Hong Kong and the Bahamas

Microbial communities of the sponges Callyspongia sp. from Hong Kong and Callyspongia plicifera (Porifera: Demospongia) from the Bahamas were compared with each other and with those from reference substrata using a terminal restriction fragment length polymorphism (T-RFLP) analysis. The least number of bacterial ribotypes and bacterial isolates were retrieved from Bahamas reference and sponge surfaces, while the bacterial communities from Hong Kong Callyspongia sp. and reference surfaces were more diverse. Microbial communities from the 2 sponges were different from each other and from reference substrata. Gas chromatographic–mass spectrometric (GC-MS) analysis of dichloromethane extracts revealed that more than 60% of the compounds were similar in the 2 species Callyspongia sp. and C. plicifera, compared to the compounds of Halichondria spp. At tissue level (TL) concentrations, both sponge extracts predominantly inhibited the growth of bacteria from reference substrata. Multifactor ANOVA revealed that the source of bacteria (sponge surface, interior, or reference substrata), the geographic location of isolates (Hong Kong or the Bahamas), thesponge extract (from Callyspongia sp. or from C. plicifera), and combinations of these factors contributed significant effects in disc diffusion assay experiments. Sponge extracts at both TL concentrations and 10× dilutions were toxic to larvae of the polychaete Hydroides elegans and the barnacle Balanus amphitrite. Our results suggest that the 2 congeneric sponges Callyspongia spp. from different biogeographic regions have different bacterial associates, while producing relatively similar secondary metabolites. It remains to be explored whether differences in sponge-associated bacterial communities will also hold for other congeneric sponge species from different regions

Estagiamento de embriões de Macrobrachium olfersi (Wiegman) (Crustacea, Palaemonidae) através de critérios morfológicos nos dias embrionários Macrobrachium olfersi (Wiegman) (Crustacea, Palaemonidae) embryo staging through morphological landmarks identified in each embryonic day

Em embriões de Macrobrachium olfersi (Wiegman, 1836) foram analisadas as características morfológicas bem como o dia do desenvolvimento em que estas características surgiram. Machos e fêmeas de M. olfersi foram coletados na Ilha de Santa Catarina e colocados em aquários de água doce, na temperatura de 26&deg;C e ciclo escuro e claro de 10:14 horas. Fêmeas ovígeras foram monitoradas diariamente para retirada de uma amostra de 20 ovos da câmara incubadora. O desenvolvimento embrionário foi caracterizado através do sistema de estagiamento diário. Embriões vivos e fixados foram analisados (48x) em intervalos de 24 horas (dia embrionário). O índice do olho foi calculado em cada dia embrionário, a partir do aparecimento da pigmentação no olho. O desenvolvimento de M. olfersi foi caracterizado em 14 dias embrionários (E), onde entre E1 a E4 ocorreu a clivagem, gastrulação, disco germinativo e organização do nauplius embrionizado. Nos dias subseqüentes foi caracterizado o crescimento do nauplius embrionizado bem como a formação e encurvamento do pós-nauplius. Em E7 observou-se a pigmentação no olho, seguida do início dos batimentos cardíacos em E8. Entre E9 e E14, ocorreu de forma mais intensa o processo de organogênese, principalmente dos sistemas nervoso, cardiovascular e digestivo. O estagiamento diário do desenvolvimento de M. olfersi permitiu o reconhecimento de diferentes formas embrionárias, bem como de ritmos de crescimento e diferenciação do embrião, os quais são essenciais à formação gradual do plano do corpo.<br>Morphological landmarks of Macrobrachium olfersi embryos were examined and their appearance times were related to each embryonic day. Males and females of M. olfersi (Wiegman, 1836) were captured in Santa Catarina Island and kept in freshwater small tanks at 26ºC and 10:14 dark: light cycle. Ovigerous females were monitored daily to remove samples of 20 eggs from brood pouch. The embryonic development was characterized through daily staging system. Living and fixed embryos were analyzed (48x) in intervals of 24 hours (embryonic day). The eye index was calculated in each embryonic day from the appearance of the eye pigmentation. The development of M. olfersi was described in 14 embryonic days (E), where the cleavage, gastrulation, germinal disk and egg nauplius are developed from E1 to E4. The subsequent days were characterized by the growth of the egg nauplius, as well by the formation and the bent of the post-nauplius. At E7, the eye pigmentation appeared and was followed by the beginning of heartbeats at E8. From E9 to E14, more intensive organogenesis processes occurred, mainly on the nervous, cardiac and digestive systems. The daily staging of development of M. olfersi development enabled the recognition of different embryonic forms, as well as growth and differentiation rhythms of embryo, which were fundamental to the gradual formation of the body plan

Perspectives on marine zooplankton lipids

We developed new perspectives to identify important questions and to propose approaches for future research on marine food web lipids. They were related to (i) structure and function of lipids, (ii) lipid changes during critical life phases, (iii) trophic marker lipids, and (iv) potential impact of climate change. The first addresses the role of lipids in membranes, storage lipids, and buoyancy with the following key question: How are the properties of membranes and deposits affected by the various types of lipids? The second deals with the importance of various types of lipids during reproduction, development, and resting phases and addresses the role of the different storage lipids during growth and dormancy. The third relates to trophic marker lipids, which are an important tool to follow lipid and energy transfer through the food web. The central question is how can fatty acids be used to identify and quantify food web relationships? With the fourth, hypotheses are presented on effects of global warming, which may result in the reduction or change in abundance of large, lipid-rich copepods in polar oceans, thereby strongly affecting higher trophic levels. The key question is how will lipid dynamics respond to changes in ocean climate at high latitudes?