Biogeography of the social wasp genus Brachygastra (Hymenoptera: Vespidade: Polistinae)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Investigation of a new acetogen isolated from an enrichment of the tammar wallaby forestomach

Background: Forestomach fermentation in Australian marsupials such as wallabies and kangaroos, though analogous to rumen fermentation, results in lower methane emissions. Insights into hydrogenotrophy in these systems could help in devising strategies to reduce ruminal methanogenesis. Reductive acetogenesis may be a significant hydrogen sink in these systems and previous molecular analyses have revealed a novel diversity of putative acetogens in the tammar wallaby forestomach.Results: Methanogen-inhibited enrichment cultures prepared from tammar wallaby forestomach contents consumed hydrogen and produced primarily acetate. Functional gene (formyltetrahydrofolate synthetase and acetyl-CoA synthase) analyses revealed a restricted diversity of Clostridiales species as the putative acetogens in the cultures. A new acetogen (growth on H-2/CO2 with acetate as primary end product) designated isolate TWA4, was obtained from the cultures. Isolate TWA4 classified within the Lachnospiraceae and demonstrated > 97% rrs identity to previously isolated kangaroo acetogens. Isolate TWA4 was a potent hydrogenotroph and demonstrated excellent mixotrophic growth (concomitant consumption of hydrogen during heterotrophic growth) with glycerol. Mixotrophic growth of isolate TWA4 on glycerol resulted in increased cell densities and acetate production compared to autotrophic growth. Co-cultures with an autotrophic methanogen Methanobrevibacter smithii revealed that isolate TWA4 performed reductive acetogenesis under high hydrogen concentration (> 5 mM), but not at low concentrations. Under heterotrophic growth conditions, isolate TWA4 did not significantly stimulate methanogenesis in a co-culture with M. smithii contrary to the expectation for organisms growing fermentatively.Conclusions: The unique properties of tammar wallaby acetogens might be contributing factors to reduced methanogen numbers and methane emissions from tammar wallaby forestomach fermentation, compared to ruminal fermentation. The macropod forestomach may be a useful source of acetogens for future strategies to reduce methane emissions from ruminants, particularly if these strategies also include some level of methane suppression and/or acetogen stimulation, for example by harnessing mixotrophic growth capabilities

Avaliação das condições bióticas e abióticas em um viveiro neotropical impactado

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Dynamics of phytoplankton associations in three reservoirs in northeastern Brazil assessed using Reynolds' theory

The aim of the present study was to evaluate the influence of seasonality on the behavior of phytoplankton associations in eutrophic reservoirs with different depths in northeastern Brazil. Five collections were carried out at each of the reservoirs at two depths (0.1 m and near the sediment) at three-month intervals in each season (dry and rainy). The phytoplankton samples were preserved in Lugol's solution and quantified under an inverted microscope for the determination of density values, which were subsequently converted to biomass values based on cellular biovolume and classified in phytoplankton associations. The following abiotic variables were analyzed: water temperature, dissolved oxygen, pH, turbidity, water transparency, total phosphorus, total dissolved phosphorus, orthophosphate and total nitrogen. The data were investigated using canonical correspondence analysis. The influence of seasonality on the dynamics of the phytoplankton community was lesser in the deeper reservoirs. Depth affected the behavior of the algal associations. Variation in light availability was a determinant of changes in the phytoplankton structure. Urosolenia and Anabaena associations were more abundant in shallow ecosystems with a larger eutrophic zone, whereas the Microcystis association was more related to deep ecosystems with adequate availability of nutrients. The distribution of Cyclotella, Geitlerinema, Planktothrix, Pseudanabaena and Cylindrospermopsis associations was different from that seen in subtropical regions and the substitution of these associations was related to a reduction in the eutrophic zone rather than the mixture zone. Published by Elsevier GmbH.

Microcystin-producing genotypes from cyanobacteria in Brazilian reservoirs

The aim of this study was to evaluate the use of new oligonucleotide primers (mcyB-F/R, mcyB-F/R-A, and mcyB-F/R-B) designed from Brazilian cyanobacteria for the detection of microcystin-producing genotypes in 27 environmental samples from water reservoirs and 11 strains of Microcystis. Microcystins were found using HPLC in all 11 strains and 19 of the environmental samples. The new oligonucleotide primers amplified fragments of microcystin-producing genes, including the eight environmental samples in which no microcystins were detected by HPLC, but which presented amplified fragments, thereby demonstrating the existence of microcystin-producing genes. The new oligonucleotide primers exhibited better specificity when used with environmental samples and were more reliable in comparison with those described in the literature (mcyB-FAA/RAA and mcyA-Cd/FR), which generate false-negative results. The better performance of these new oligonucleotide primers underline the need for designing molecular markers that are well fitted to the regional biological diversity. As this is a fast predictive technique for determining the presence or absence of microcystins, it could be used either alone or in conjunction with other techniques, such as the screening of samples to be sent for quantitative toxicological analysis using HPLC, thereby reducing monitoring cost and time. (c) 2010 Wiley Periodicals, Inc. Environ Toxicol, 2012.

Degradation of [D-Leu]-Microcystin-LR by solar heterogeneous photocatalysis (TiO2)

The present study investigates the use of solar heterogeneous photocatalyis (TiO2) for the destruction of [D-Leu]-Microcystin-LR, powerful toxin of widespread occurrence within cyanobacteria blooms. We extracted [D-Leu]-Microcystin-LR from a culture of Microcystis spp. and used a flat plate glass reactor coated with TiO2 (Degussa, P25) for the degradation studies. The irradiance was measured during the experiments with the aid of a spectroradiometer. After the degradation experiments, toxin concentrations were determined by HPLC and mineralization by TOC analyses. Acute and chronic toxicities were, quantified using mice and phosphatase inhibition in vitro assays, respectively. According to the performed experiments, 150 min were necessary to reduce the toxin concentration to the WHO's guideline for drinking water (from 10 to 1 mu g L-1) and to mineralize 90% of the initial carbon content. Another important finding is that solar heterogeneous photocatalysis was a destructive process indeed, not only for the toxin, but also for the other extract components and degradation products generated. Moreover, toxicity tests using mice have shown that the acute effect caused by the initial sample was removed. However, tests using the phosphatase enzyme indicated that it may be formed products capable of inducing chronic effects on mammals. The performed experiments indicate the feasibility of using solar heterogeneous photocatalysis for treating contaminated water with [D-Leu]-Microcystin-LR, not only due to its destruction, but also to the significant removal of organic matter and acute toxicity that can be achieved. (C) 2012 Elsevier Ltd. All rights reserved.

Biomonitoring of Microcystin and Aflatoxin Co-Occurrence in Aquaculture Using Immunohistochemistry and Genotoxicity Assays

This work investigated the effects of co-occurring aflatoxin B-1 (AFB(1)) and microcystin (MC) in aquaculture, using immunohistochemistry and genotoxicity methods. Tilapia (Oreochromis niloticus) were exposed to AFB(1) by intraperitoneal and MC (cell extract of Microcystis aeruginosa) by intraperitoneal and immersion routes. The interaction of MC-AFB(1) was evaluated co-exposing the intraperitoneal doses. Blood samples were collected after 8, 24, and 48h to analyze the micronucleus frequency and comet score. The interaction of MC-AFB(1) showed a synergic mutagenic response by higher micronucleus frequency of co-exposed group. A slight genotoxic synergism was also observed in the comet score. Immunohistochemistry detected MC in al lthe fish liver tissues exposed to MC by intraperitoneal route, and only the immersed group with the highest dose of MC showed a positive response. Although MC was non-detectable in the edible muscle, the combination of immunohistochemistry with genotoxicity assay was an attractive biomonitoring tool in aquaculture, where the animals were frequently exposed to co-occurring synergic hazards.

Bioaccumulation Of Microcystins In Lettuce

The contamination of lettuce (Lactuca sativa L.) by water-borne crude extracts of the cyanobacterium microcystin-producing Microcystis aeruginosa (Kutzing) Kutzing was investigated. The aim of the study was to determine whether bioaccumulation of microcystins occurs in lettuce foliar tissue when sprayed with solutions containing microcystins at concentrations observed in aquatic systems (0.62 to 12.5 mu g center dot L-1). Microcystins were found in lettuce foliar tissues (8.31 to 177.8 mu g per Kg of fresh weight) at all concentrations of crude extracts. Spraying with water containing microcystins and cyanobacteria may contaminate lettuce at levels higher than the daily intake of microcystins recommended by the World Health Organization (WHO), underscoring the need to monitor such food exposure pathways by public authorities.

Convergent evolution of [D-Leucine1] microcystin-LR in taxonomically disparate cyanobacteria

Abstract Background Many important toxins and antibiotics are produced by non-ribosomal biosynthetic pathways. Microcystins are a chemically diverse family of potent peptide toxins and the end-products of a hybrid NRPS and PKS secondary metabolic pathway. They are produced by a variety of cyanobacteria and are responsible for the poisoning of humans as well as the deaths of wild and domestic animals around the world. The chemical diversity of the microcystin family is attributed to a number of genetic events that have resulted in the diversification of the pathway for microcystin assembly. Results Here, we show that independent evolutionary events affecting the substrate specificity of the microcystin biosynthetic pathway have resulted in convergence on a rare [D-Leu1] microcystin-LR chemical variant. We detected this rare microcystin variant from strains of the distantly related genera Microcystis, Nostoc, and Phormidium. Phylogenetic analysis performed using sequences of the catalytic domains within the mcy gene cluster demonstrated a clear recombination pattern in the adenylation domain phylogenetic tree. We found evidence for conversion of the gene encoding the McyA2 adenylation domain in strains of the genera Nostoc and Phormidium. However, point mutations affecting the substrate-binding sequence motifs of the McyA2 adenylation domain were associated with the change in substrate specificity in two strains of Microcystis. In addition to the main [D-Leu1] microcystin-LR variant, these two strains produced a new microcystin that was identified as [Met1] microcystin-LR. Conclusions Phylogenetic analysis demonstrated that both point mutations and gene conversion result in functional mcy gene clusters that produce the same rare [D-Leu1] variant of microcystin in strains of the genera Microcystis, Nostoc, and Phormidium. Engineering pathways to produce recombinant non-ribosomal peptides could provide new natural products or increase the activity of known compounds. Our results suggest that the replacement of entire adenylation domains could be a more successful strategy to obtain higher specificity in the modification of the non-ribosomal peptides than point mutations.

Biomonitoring of microcystin and aflatoxin co-occurrence in aquaculture using immunohistochemistry and genotoxicity assays

This work investigated the effects of co-occurring aflatoxin B1 (AFB1) and microcystin (MC) in aquaculture, using immunohistochemistry and genotoxicity methods. Tilapia (Oreochromis niloticus) were exposed to AFB1 by intraperitoneal and MC (cell extract of Microcystis aeruginosa) by intraperitoneal and immersion routes. The interaction of MC-AFB1 was evaluated co-exposing the intraperitoneal doses. Blood samples were collected after 8, 24, and 48h to analyze the micronucleus frequency and comet score. The interaction of MC-AFB1 showed a synergic mutagenic response by higher micronucleus frequency of co-exposed group. A slight genotoxic synergism was also observed in the comet score. Immunohistochemistry detected MC in al lthe fish liver tissues exposed to MC by intraperitoneal route, and only the immersed group with the highest dose of MC showed a positive response. Although MC was non-detectable in the edible muscle, the combination of immunohistochemistry with genotoxicity assay was an attractive biomonitoring tool in aquaculture, where the animals were frequently exposed to co-occurring synergic hazards.

Isolierung, Charakterisierung und Nachweis methanogener Archaea aus laufenden Praxis-NawaRo-Biogasanlagen unter besonderer Beruecksichtigung der Gattung Methanobacterium

Im Verlauf der Forschungsarbeit wurden Proben aus fünf, mit nachwachsenden Rohstoffen (NawaRo) beschickten, landwirtschaftlichen Biogasanlagen (BGA) auf die Biozönose methanogener Archaea hin molekularbiologisch untersucht. Über „amplified rDNA restriction analysis“-Screening (ARDRA) von Bibliotheken auf Basis von 16S rRNA-Genfragmenten konnte anhand zweier beispielhafter BGA das Vorkommen von Vertretern der Gattungen Methanoculleus (Mcu.), Methanobacterium (Mb.), Methanosarcina (Msc.) und Methanosaeta (Mst.) nachgewiesen werden. Mittels denaturierender Gradienten-Gelelektrophorese (DGGE) wurde das Vorkommen dieser Mikroorganismen auch in den übrigen Anlagen gezeigt. Ergänzend dazu wurde in drei Anlagen Methanospirillum hungatei nachgewiesen. Nach Ausarbeitung gattungsspezifischer Isolierungsstrategien konnten insgesamt zehn Vertreter der Gattung Methanobacterium (Isolate Mb1 bis Mb10) und jeweils ein Vertreter der Gattungen Methanoculleus (Isolat Mcu(1)), Methanosarcina (Isolat NieKK) und Methanosaeta (Isolat Mst1.3) aus den BGA-Proben isoliert werden. Durch in silico-Abgleich der partiellen 16S rRNA-Gensequenzen wurden diese als Verwandte von Mb. formicicum MFT, Mcu. bourgensis MS2T, Msc. mazei S-6T und Mst. concilii FE mit einer Sequenzidentität > 97% identifiziert. Im Laufe weiterer molekularbiologischer Untersuchungen mittels DGGE und ARDRA-Analyse konnten die Isolate den Referenzstämmen zugeordnet werden. In Bezug auf die Gattung Methanobacterium ergaben sich jedoch leichte Abweichungen. Diese bestätigten sich in vergleichenden Analysen des genomischen Fingerabdrucks in der „specifically amplified polymorphic DNA“-PCR (SAPD-PCR), welche im Rahmen dieser Arbeit erstmalig erfolgreich auf archaeelle Organismen angewandt wurde. Hier zeigten die Isolate zwei von den Fingerabdrücken der untersuchten Referenzstämme verschiedene Hauptamplifikationsmuster. Aufgrund der Vielzahl der Isolate sowie dem signifikanten Vorkommen in qPCR-Analysen und Klonbibliotheken fokussierten sich die weiteren Arbeiten zur genauen Untersuchung dieser Abweichungen auf phylogenetische Analysen der Gattung Methanobacterium und die Entwicklung von Nachweissystemen. Die Aufklärung eines Großteils der 23S rRNA-Gensequenzen der Isolate und von ausgewählten Typstämmen ermöglichte ergänzende phylogenetische Untersuchungen zu durchgeführten 16S rRNA-Analysen. Dabei wurden die Isolate jeweils in einem eigenen Cluster abseits der meisten Referenzstämme aus der Gattung Methanobacterium positioniert. Analog zur Musterbildung im Rahmen der SAPD-Analyse zeigte sich eine Differenzierung in zwei Äste und ergab in Übereinstimmung mit den in silico-Sequenzabgleichen den höchsten Verwandtschaftsgrad mit Mb. formicicum MFT. Die Eignung der SAPD-PCR zur Ableitung spezifischer Primerpaare konnte erstmals auch für methanogene Archaea gezeigt werden. Die Ableitung zweier Primerpaare mit Spezifität für die Methanobacterium-Isolate Mb1 bis Mb10 sowie für den Typstamm Mb. formicicum MFT gelang und konnte im Rahmen eines Direkt-PCR-Nachweises erfolgreich auf Reinkulturen und Fermenterproben angewandt werden. Unter Einbezug der sequenzierten 23S rRNA-Genfragmente gelang die Erstellung von Oligonukleotid-Sonden für den Einsatz in Fluoreszenz in situ-Hybridisierungsexperimenten. Im Praxistest ergab sich für diese Sonden eine Spezifität für alle getesteten Vertreter der Gattung Methanobacterium sowie für Methanosphaera stadtmanae MCB-3T und Methanobrevibacter smithii PST.rnSomit konnten im Laufe der Arbeit die dominanten methanogenen Archaea in NawaRo-BGA in mehrphasigen Experimenten nachgewiesen, quantifiziert und auf nur wenige Gattungen eingegrenzt werden. Vertreter der vier dominanten Gattungen wurden isoliert und Nachweissysteme für Arten der Gattung Methanobacterium erstellt.rn

Proceedings of the Third Biochemical Engineering Symposium (April 28, 1973)

This report presents the proceedings of the Biochemical Engineering Symposium held at Kansas State University, April 28, 1973. Since a number of the contributions will be published in detail elsewhere, only brief summaries of each contribution are included here. Requests for additional information on projects conducted at The University of Nebraska should be directed to Dr. Peter J. Reilly, and those at Kansas State University to the editors. ContentsKenneth J. Jacobson, Andrew H.C. Chan, and Raymond C. Eliason, "Properties and Utilization of Small Particulates in Cattle Manure" Cady R. Engler and James S. Yohn, "Protein from Manure" Robert J. Williams, "Kinetics of Sucrose Inversion Using Invertase Immobilized on Hollow Fibers of Cellulose Acetate" David F. Aldis and Thomas A. Carlisle, "Study of a Triiodide-Resin Complex Disinfection System" John C. Heydweiller, "Modeling and Analysis of Symbiotic Growth" Kenneth J. Jacobson, "Synchronized Growth of the Blue Green Alga Microcystis aeruginosa" Clarence C. Y. Ron arui Lincoln L. S. Yang, "Computer Modeling of the Reductive Pentose Phosphate Cycle" Ming-ching T. Kuo, "Application of a Parallel Biochemical Oxidation Kinetic Model to the Design of an Activated Sludge System Including a Primary Clarifier" Prakash N. Mishra, "Optimal Synthesis of Water Renovation Systems"

Diatom biostratigraphy and datum levels of sediments from ODP Leg 167 sites

Ocean Drilling Program Leg 167 represents the first time since 1978 that the North American Pacific margin was drilled to study ocean history. More than 7500 m of Quaternary to middle Miocene (14 Ma) sediments were recovered from 13 sites, representing the most complete stratigraphic sequence on the California margin. Diatoms are found in most samples in variable abundance and in a moderately well-preserved state throughout the sequence, and they are often dominated by robust, dissolution-resistant species. The Neogene North Pacific diatom zonation of Yanagisawa and Akiba (1998, doi:10.5575/geosoc.104.395) best divides the Miocene to Quaternary sequences, and updated ages of diatom biohorizons estimated based on the geomagnetic polarity time scale of Cande and Kent (1995, doi:10.1029/94JB03098) are slightly revised to adjust the differences between the other zonations. Most of the early middle Miocene through Pleistocene diatom datum levels that have been proven to be of stratigraphic utility in the North Pacific appear to be nearly isochronous within the level of resolution constrained by sample spacing. The assemblages are characterized by species typical of middle-to-high latitudes and regions of high surface-water productivity, predominantly by Coscinodiscus marginatus, Stephanopyxis species, Proboscia barboi, and Thalassiothrix longissima. Latest Miocene through Pliocene assemblages in the region of the California Current, however, are intermediate between those of subarctic and subtropical areas. As a result, neither the existing tropical nor the subarctic (high latitude) zonal schemes were applicable for this region. An interval of pronounced diatom dissolution detected throughout the Pliocene sequence apparently correspond to a relatively warmer paleoceanographic condition resulting in a slackening of the southward flow of the California Current.

(Table 1) Presence of sublittoral macroalgae in the investigated profiles in Potter Cove, King George Island, Antarctica

The vegetation of a small fjord and its adjacent open shore was documented by subaquatic video. The distribution of individual species of macroalgae and the composition of assemblages were compared with gradients of light availability, hydrography, slope inclination, substratum, and exposition to turbulence and ice. The sublittoral fringe is usually abraded by winterly ice floes and devoid of large, perennial algae. Below this zone, the upper sublittoral is dominated by Desmarestia menziesii on steep rock faces, where water movements become irregular, or by Ascoseira mirabilis and Palmaria decipiens on weakly inclined slopes with steady rolling water movements. In the central sublittoral above 15 m, where turbulence is still active, Desmarestia anceps is outcompeting all other species on solid substratum, However, the species is not able to persist on loose material under these conditions. Instead, Himantothallus grandifolius may occur. Deeper, where turbulence usually is negligible, Desmarestia anceps also covers loose material. The change of dominance to Himantothallus grandifolius in the deep sublittoral cannot completely be explained at present. Himantothallus grandifolius also prevails in a mixed assemblage under the influence of grounding icebergs. Most of the smaller algae are opportunists with different degrees of tolerance for turbulence, but some apparently need more stable microhabitats and thus are dependent from continuing suppression of competitive large phaeophytes.

Pliocene and Pleistocene abundance of siliceous microfossil assemblages in ODP Leg 127 sites

A close examination of the siliceous microfossil assemblages from the sediments of ODP Leg 127, Japan Sea Sites 794, 795, and 797, reveals that upper Pliocene and Pleistocene assemblages have been subjected to more dissolution than have lower Pliocene assemblages. This conclusion is based on semiquantitative observations of samples processed for diatoms and radiolarians. Although preservation of opaline microfossils in some upper Pliocene and Pleistocene samples is better than others, in general, the poorly preserved state of these assemblages supports the notion that opal dissolution, in response to lowered productivity, is responsible for the paucity of siliceous microfossils in upper Pliocene and Pleistocene sediments. The lithological transition from diatomaceous oozes to silts and clays corresponds to a change between dominantly well preserved to more poorly preserved siliceous assemblages, and is termed the late Pliocene Japan Sea opal dissolution transition zone (ODTZ). The base of the ODTZ is defined as the uppermost occurrence of high abundances of moderately to well preserved valves of the diatom Coscinodiscus marginatus. The dissolution transition zone is characterized by partially dissolved refractory assemblages of radiolarians, the presence of C. marginatus girdles, C. marginatus fragments, siliceous sponge spicules, and a general decrease in weakly silicified, less solution resistant diatoms upward in the section. The top of the dissolution transition zone marks the level where whole C. marginatus valves and C. marginatus fragments are no longer present in significant numbers. Dissolution of the late Pliocene and Pleistocene opaline assemblages is attributed mainly to changes in paleoceanographic circulation patterns and decreased nutrient (dissolved silicon) contents of the water column, and possibly dissolution at the sediment/water interface, rather than to post-depositional dissolution or diagenesis. We suggest that the transition from silica-rich to silica-poor conditions in the Japan Sea was due to fluctuations of deep-water exchange with the Pacific through the Tsugaru Strait between 2.9 and 2.3 Ma.