Comparison of two membrane – photobioreactors, with free or immobilized cells, for the production of pigments by a marine diatom

The present study concerns the value enhancement of the microalga Haslea ostrearia. This marine diatom bears the peculiarity of synthesizing and secreting in the culture medium a blue-green pigment named "marennine". Anticancer research, cosmetics and aquaculture are the fields concerned with the utilizations of this hydrosoluble pigment. The aim of the study is to compare the pigment productivity obtained with two types of photobioreactors. In the first process, cells are free and recycled in a bioreactor combined with a membrane ultrafiltration equipment (external loop). In the second system, cells are entrapped in a tubular agar gel layer in a photobioreactor of original design. The influence of nitrate concentration and renewal rate is examined. Experiments, conducted on long term periods (up to 40 d) without any external contamination, revealed that marennine productivities of more than 5-7 mg 10⁹ cell^у d^у can be reached with both bioreactors. The advantages and drawbacks of each process design are also discussed.     

Characterization of β-N-acetylglucosaminidase from a marine Pseudoalteromonas sp. for application in N-acetyl-glucosamine production

The psychrotolerant Pseudoalteromonas issachenkonii PAMC 22718 was isolated for its high exo-acting chitinase activity in the Kara Sea, Arctic. An exo-acting chitinase (W-Chi22718) was homogeneously purified from the culture supernatant of PAMC 22718, the molecular weight of which was estimated to be approximately 112?kDa. Due to its β-N-acetylglucosaminidase activity, W-Chi22718 was able to produce N-acetyl-D-glucosamine (GlcNAc) monomers from chitin oligosaccharide substrates. W-Chi22718 displayed chitinase activity from 0 to 37°C (optimal temperature of 30°C) and maintained activity from pH 6.0 to 9.0 (optimal pH of 7.6). W-Chi22718 exhibited a relative activity of 13 and 35% of maximal activity at 0 and 10°C, respectively, which is comparable to the activities of previously characterized, cold-adapted bacterial chitinases. W-Chi22718 activity was enhanced by K⁺, Ca²⁺, and Fe²⁺, but completely inhibited by Cu²⁺ and SDS. We found that W-Chi22718 can produce much more (GlcNAcs) from colloidal chitin, working together with previously characterized cold-active endochitinase W-Chi21702. Genome sequencing revealed that the corresponding gene (chi22718_IV) was 2,856?bp encoding a 951?amino acid protein with a calculated molecular weight of approximately 102?kDa.     

Accuracy of body mass estimates of formalin-preserved fish – a review

This paper highlights possible effects of physical and chemical mechanisms of formalin fixation and preservation on biological tissue and reviews the consequent potential inaccuracies on estimates of body mass of small fishes fixed and preserved in formalin. Twenty-six papers including 65 independent experiments with 35 species which examine effects of formalin on body mass estimates on small fishes are included. The effect of the formalin on the specimens depends on the salinity of the water used to dilute the commercial formalin (usually 1:9 formalin: water) before being used to fixate and preserve fish. Mean wet body mass of the specimens from the studies using seawater or fresh water diluted formalin deceases by 13% and increases by 7%, respectively, from before to after being immersed in formalin. The same trend is found with condition factor in the few papers that report this parameter. Body length decreases on average by c. 2% in fixated and preserved fish regardless of whether the formalin is diluted in seawater or fresh water.     

Inert filter media for the biofiltration of waste gases – characteristics and biomass control

Soil biofilters and related systems based onthe use of natural filter beds have been usedfor several years for solving specific airpollution problems. Over the past decade,significant improvements have been brought tothese original bioprocesses, among which thedevelopment and use of new inert packingmaterials. The present paper overviews the mostcommon inert packings used in biofiltration ofwaste gases and their major characteristics. Apotential problem recently encountered whenusing inert filter beds is the heterogenousdistribution of biomass on the packingmaterial, and the excessive growth andaccumulation of biomass when treating highorganic loads, eventually leading to cloggingof the biofilter and reduced efficiency.Several strategies that have been proposed forsolving such problems are described in thispaper. Technologies for controlling excessbiomass accumulation can be grouped into fourcategories based on the use of mechanicalforces, the use of specific chemicals, thereduction of microbial growth, and predation.     

Biodiesel-TBL+: A new hierarchical sustainability assessment framework of PC&I for biodiesel production – Part I

Sustainability assessment of biodiesel production is a topic of increasing importance due to the interest of governments to define sovereignty strategies and diversification of their energy matrix, and to set up the impact of biofuels production. In this context, this work aims to propose a hierarchical structure of sustainability assessment that integrates dimensions of sustainable development with principles, criteria and indicators (PC&I). The method employed to define the hierarchical structure was a comprehensive literature review, based on information search strategy and classification. About 400 documents were reviewed and 103 documents were ultimately selected, including laws, policy documents, certificates, directives and other normative documents and papers published in peer-reviewed journals. The first result of the analysis was the need to strengthen identification of the sustainable development assessment, adding the political and technological dimensions to the three traditional dimensions, social, economic and environmental, studied in this kind of evaluation. The second result was the proposal of a hierarchical framework for the sustainability assessment of biodiesel production, organized in four levels: the first level comprises the five dimensions associated with sustainable development evaluation, the second includes 13 principles, the third contains 40 criteria and the fourth level corresponds to a set of indicators that describes each criterion. Outcomes of this work provide a foundation for further discussion of sustainability assessments for biodiesel production and its potential application in specific contexts.     

Proteomic evidence of a paedomorphic evolutionary process within a marine snail species: a strategy for adapting to extreme ecological conditions?

The exposed and sheltered ecotypes of the marine snail Littorina saxatilis from European rocky shores are considered a key model system to study adaptation and ecological speciation. Previous studies showed that two ecotypes (RB and SU) of this species in NW Spain have adapted differently to different shore levels and microhabitats. In order to understand how this divergent adaptive process has been accomplished, we followed a quantitative proteomic approach to investigate the proteome variation in a number of different biological factors, that is, ecotype, ontogeny and their interactions. This approach allowed testing the hypothesis that one of the ecotypes has evolved by paedomorphosis, and also whether or not the molecular mechanisms related to ecotype differentiation are set up in early developmental stages. Additionally, the identification of some candidate proteins using mass spectrometry provides some functional insights into these evolutionary processes. Results from this study provided evidence of higher ontogenetic differentiation at proteome level in the RB (metamorphic) than in SU (paedomorphic) ecotype that point to the possibility of juvenile stage retention in this latter ecotype. The level of protein expression (proteome) differences between ecotypes maintained nearly constant from late embryonic stages to adulthood, although some proteins involved in these changes considerably differed in embryonic compared to other ontogenetic stages. Paedomorphosis may be the evolutionary response of the SU ecotype of solving the trade‐off during sexually immaturity that is caused by the evolution of small size arising from adaptation to the wave‐exposed habitat. Some potential candidate genes of adaptation related to energetic metabolism have been identified, providing a promising baseline for future functional analyses.     

Is increased male flower production a strategy for avoidance of predispersal seed predation in andromonoecious plants?

Floral gender in angiosperms often varies within and among populations. We conducted a field survey to test how predispersal seed predation affects sex allocation in an andromonoecious alpine herb Peucedanum multivittatum. We compared plant size, male and perfect flower production, fruit set, and seed predation rate over three years among nine populations inhabiting diverse snowmelt conditions in alpine meadows. Flowering period of individual populations varied from mid‐July to late August reflecting the snowmelt time. Although perfect flower and fruit productions increased with plant size, size dependency of male flower production was less clear. The number of male flowers was larger in the early‐flowering populations, while the number of perfect flowers increased in the late‐flowering populations. Thus, male‐biased sex allocation was common in the early‐flowering populations. Fruit‐set rates varied among populations and between years, irrespective of flowering period. Fruit‐set success of individual plants increased with perfect flower number, but independent of male flower number. Seed predation by lepidopteran larvae was intense in the early‐flowering populations, whereas predation damage was absent in the late‐flowering populations, reflecting the extent of phenological matching between flowering time of host plants and oviposition period of predator moths. Seed predation rate was independent of male and perfect flower numbers of individual plants. Thus, seed predation is a stochastic event in each population. There was a clear correlation between the proportion of male flowers and the intensity of seed predation among populations. These results suggest that male‐biased sex allocation could be a strategy to reduce seed predation damage but maintain the effort as a pollen donor under intensive seed predation.     

Biogeography of a southern hemisphere freshwater fish: how important is marine dispersal?

Galaxias maculatus is one of the world's most widely distributed freshwater fish. This species has a marine-tolerant juvenile phase, and a geographical range extending through much of the southern hemisphere. We conducted phylogeographic analyses of 163 control region haplotypes of G. maculatus, including samples from New Zealand (five locations), Tasmania (one location) and Chile (one location). A lack of genetic structure among New Zealand samples suggests that marine dispersal facilitates considerable gene flow on an intra-continental scale. The discovery of a Tasmanian-like haplotype in one of 144 New Zealand samples indicates that inter-continental marine dispersal occurs but is insufficient to prevent mitochondrial DNA differentiation among continents. The sister relationship of Tasmanian and New Zealand clades implies that marine dispersal is an important biogeographical mechanism for this species. However, a vicariant role in the divergence of eastern and western Pacific G. maculatus cannot be rejected.     

Daily variation of marine cladoceran densities in a tropical bay – Brazil

This contribution presents the daily variation of marine cladoceran densities in Guanabara Bay. The samples were obtained by vertical tows with a 200 m mesh-size conical net at different times over a 4-day period in September, 1995. Penilia avirostris was the most common species, followed by Evadne tergestina and E. spinifera. These organisms presented higher densities at nightfall. Physical factors like tide and light are responsible for the highest densities. High tide and nightfall time are requested conditions for the P. avirostris and E. tergestina abundance. Temperature and salinity appear to have no relation with cladoceran densities.     

Is there a fixed number of niches for endoparasites of fish?

Kennedy and Guégan, based on Cornell and Lawton (J Anim Ecol 1992;61:1–12), found a curvilinear relationship (the fundamental form of the relationship for parasite communities) between infracommunity and component community richness, and interpreted this as meaning that only processes acting within the infracommunities can explain the limitation in the number of parasite species in a given host. The research described here shows that an asymptotic relationship is the consequence of the differential likelihoods of parasite species to appear in an infracommunity as determined by transmission rates and intrinsic lifespans. Processes operating at the infracommunity level are not necessary to explain the curvilinear relationship. Even communities much richer than those found in European freshwater fishes cannot be assumed to be saturated in the sense that further species cannot be added over evolutionary time.     

The effect of slow-growth strategy on a production of Petunia × hybrida Vilm. microcuttings

Petunia × hybrida Vilm. is a fast-growing ornamental plant that was cultured under varying storage conditions to address seasonal fluctuations in microcutting demand. The effects of storage period (16 to 32 wk), temperature (15 to 23°C), low and high light intensity, sucrose (1 to 5% w/v), and mannitol (0 to 4% w/v) in factorial arrangements were analyzed. Stored and non-stored shoots were compared for microcutting production, harvested twice at 3-wk intervals, and were subsequently transferred to the greenhouse for 17 d. Nearly all plants from 16-wk storage survived well at all treatment conditions and the quality and quantity of microcuttings were enhanced from shoots stored at 15°C and 3% (w/v) sucrose, without mannitol for all storage periods. Another experiment tested 11- to 25-wk storage period with Petunia hybrida ‘Ragtime’ and ‘Suncatcher’ at 12°C and low light intensity. Repeated cycles of microcutting at 2-wk intervals were extended with ex vitro rooting in the greenhouse for 15 d. More and better quality microcuttings were obtained from the second and third cutting cycles than from the first or fourth cycles. By reducing temperature and light intensity, Petunia hybrida was successfully stored for 32 wk (without mannitol). A seasonal schedule with a short production window, followed by cutting large numbers of high-quality shoot-tips, could be affected and efficiently managed through storage. The value of stored shoots was enhanced by extending the number of times a shoot could be cut over repeated cutting cycles with a gain in microcutting quality.

     

Agricultural land use changes – a scenario-based sustainability impact assessment for Brandenburg,Germany

Decisions for agricultural management are taken at farm scale. However, such decisions may well impact upon regional sustainability. Two of the likely agricultural management responses to future challenges are extended use of irrigation and increased production of energy crops. The drivers for these are high commodity prices and subsidy policies for renewable energy. However, the impacts of these responses upon regional sustainability are unknown. Thus, we conducted integrated impact assessments for agricultural intensification scenarios in the federal state of Brandenburg, Germany, for 2025. One Irrigation scenario and one Energy scenario were contrasted with the Business As Usual (BAU) scenario. We applied nine indicators to analyze the economic, social and environmental effects at the regional, in this case district scale, which is the smallest administrative unit in Brandenburg. Assessment results were discussed in a stakeholder workshop involving 16 experts from the state government.The simulated area shares of silage maize for fodder and energy were 29%, 37% and 49% for the BAU, Irrigation, and Energy scenarios, respectively. The Energy scenario increased bio-electricity production to 41% of the demand of Brandenburg, and it resulted in CO₂ savings of up to 3.5 million tons. However, it resulted in loss of biodiversity, loss of landscape scenery, increased soil erosion risk, and increased area demand for water protection requirements. The Irrigation scenario led to yield increases of 7% (rapeseed), 18% (wheat, sugar beet), and 40% (maize) compared to the BAU scenario. It also reduced the year-to-year yield variability. Water demand for irrigation was found to be in conflict with other water uses for two of the 14 districts. Spatial differentiation of scenario impacts showed that districts with medium to low yield potentials were more affected by negative impacts than districts with high yield potentials.In this first comprehensive sustainability impact assessment of agricultural intensification scenarios at regional level, we showed that a considerable potential for agricultural intensification exists. The intensification is accompanied by adverse environmental and socio-economic impacts. The novelty lies in the multiscale integration of comprehensive, agricultural management simulations with regional level impact assessment, which was achieved with the adequate use of indicators. It provided relevant evidence for policy decision making. Stakeholders appreciated the integrative approach of the assessment, which substantiated ongoing discussions among the government bodies. The assessment approach and the Brandenburg case study may stay exemplary for other regions in the world where similar economic and policy driving forces are likely to lead to agricultural intensification.     

Mariculture in Israel – past achievements and future directions in raising rotifers as food for marine fish larvae

Marine fish production is now being carried out afteralmost two decades of research. The production ofseabream (Sparus aurata), which reached over 750tons in 1995, is expected to reach an annualproduction ranging between 4000 - 12 700 metric tonsby year 2010. The anticipated introduction of newspecies and its expansion to the Mediterranean shoreline will help in leading the increased maricultureproduction. Two marine fish hatcheries that operatetoday in Israel produce 7 million fingerlings a year.Traditionally, aquaculture in Israel raises fish ininland freshwater ponds and irrigation reservoirs. Inaddition, Lake Kinneret, the only freshwater lake inIsrael, is stocked yearly with juvenile fish raised inlocal hatcheries (tilapia) or imported fromMediterranean countries (mugil). While culture offreshwater teleost species (carp) was introduced morethan fifty years ago, mariculture started on acommercial scale less than 5 years ago. The limitedsupply of freshwater will accelerate the futureculture of marine species.The bottleneck of almost all marine finfish productionlies in obtaining adequate numbers of fingerlings, dueto their high mortality at early life stages. Theproduction is hindered by inadequate supply of food toearly larval stages which require live food.Development of technologies in Israel for masscultivation of food chain organisms including algae,rotifers and brine shrimp followed their developmentin other parts of the world, most notably thoseachieved in Japan. The local commercial scaleproduction of rotifers relies on several batch orsemi-continuous cultures in conical or flatbottomrectangular containers that supply daily 0.6-4billion rotifers in each hatchery. Originally arelatively large local Brachionus plicatilisstrain was used, but later smaller B.rotundiformis strains were introduced, resulting ina mixture of undefined strains. The incorporation ofalgae (Nannochloropsis sp.) generated in highyield raceways contributes to the reliability ofrotifer cultures. Algae are supplied directly from theraceways or centrifuged and stored as a frozen pasteuntil required in the hatchery. The current dependablesupply of live cultures reduces the need for preservedstocks of rotifers, either as resting eggs or keptalive at low temperatures. To the fish grower,rotifers are live food capsules that deliver essentialnutrients (e.g. long chain unsaturated fatty acids)for growth and survival of fish larvae. Research aimedat replacing live food with chemically definedmicrodiets could reveal physiological principles inprey recognition and digestion of food by marine fishlarvae.     

Trends in inulinase production – a review

This article highlights the research work carried out in the production of inulinases from various inulin substrates using strains of bacteria, yeast and fungi. Inulin is one of the numerous polysaccharides of plant origin that contains glucose or fructose. It is used as a substrate in industrial fermentation processes and in food industries due to its relatively cheap and abundant source for the microbiological production of high-fructose syrups, ethanol and acetone–butanol. The various oligosaccharides derived from inulin also find their application in the medical and dietary sector. The inulinase acts on the β-(2,1)-D-fructoside links in inulin releasing D-fructose. Hence, this article illustrates the capability of various microbes in hydrolyzing the carbon at its optimum nutrient concentration and operating condition towards inulinase production.     

Treatment of winery effluent with upflow anaerobic sludge blanket (UASB) – granular sludges enriched with Enterobacter sakazakii

Three upflow anaerobic sludge blankets (UASBs) were evaluated for the treatment of winery wastewater: the first was seeded with granular sludge enriched with Enterobacter sakazakii and reached a 90% COD removal within 17 d at hydraulic retention time of 24 h; the second was seeded with brewery granules and achieved 85% COD removal within 50 d, the third was seeded with just sludge and showed the typical problems encountered with conventional sludge seeding and had continuously to be re-seeded. A PCR-based technique was developed for the rapid detection of E. sakazakii in the granular sludge.     

Length–weight relationships of 12 marine fish species from the Pacific coast of Guatemala associated with small-scale fisheries

The length–weight relationships (LWRs) were estimated for 12 fish species. The species were collected monthly from the commercial catch of small-scale fisheries using gillnets (mesh size 7.6–15.2 cm, length 200–1,000 m, 6–48 hr of operation during the day) and longlines (surface and bottom, 300 hooks, sardine bait, operation during the day) in the period October 2017 to July 2018 along the Pacific coast of Guatemala. Most values for the parameter (b) of the length-weight equations were within the commonly expected range (2.50–3.50) except for two species: Bagre pinnimaculatus (2.22) and Menticirrhus panamensis (3.56). All values for the coefficient of determination (r²) were above .95 and thus the estimates can be considered reliable. Besides novel LWRs we provide for some species estimates which include a new TLmax not yet involved of any LWR studies.     

Creation and maintenance of habitat downstream from a weir for the greenside darter, Etheostoma blennioides – a rare fish in Canada

The biology, microhabitat use and migratory behaviour of the greenside darter, Etheostoma blennioides, was studied at the Mannheim Weir on the Grand River, Ontario during the summer of 1995 and 1996. Officially listed as vulnerable in Canada, greenside darters reached maturity at age 1 and lived up to 4 years. They were found in riffle habitats that consisted of cobble and loose boulders, with large mats of Cladophora. This type of unembedded substrate is uncommon in the Grand River watershed. However, local abundance of greenside darters immediately downstream from the Mannheim Weir was likely due to high water velocities from weir discharge, freshets and ice scour which help maintain unembedded riffle areas. Trap data indicated that greenside darters temporally partition this habitat with the stonecat, Noturus flavus. Other darter species were not commonly found in areas with greenside darters, whose depth selection and habitat choices were influenced by predators and morphology. Denil fishways at the Mannheim Weir rarely passed greenside darters due to prohibitively high water velocities and exclusion by larger fish. This revised version was published online in August 2006 with corrections to the Cover Date.