Letteratura scientifica selezionata sul tema "Hawkesbury region, N.S.W., ecology"

ABSTRACT Production of phenazine antibiotics by the biological control bacterium Pseudomonas aureofaciens 30-84 is regulated in part by the PhzI/PhzR N-acyl-homoserine lactone (AHL) response system (L. S. Pierson III, V. D. Keppenne, and D. W. Wood, J. Bacteriol. 176:3966–3974, 1994; D. W. Wood and L. S. Pierson III, Gene 168:49–53, 1996). Two mutants, 30-84W and 30-84.A2, were isolated and were found to be deficient in the production of phenazine, protease, hydrogen cyanide (HCN), and the AHL signal N-hexanoyl-homoserine lactone. These mutants were not complemented by phzI, phzR, or the phenazine biosynthetic genes (phzFABCD) (L. S. Pierson III, T. Gaffney, S. Lam, and F. Gong, FEMS Microbiol. Lett. 134:299–307, 1995). A 2.2-kb region of the 30-84 chromosome which fully restored production of all of these compounds in strain 30-84W was identified. Nucleotide sequence analysis of this region revealed a single open reading frame encoding a predicted 213-amino-acid protein which is very similar to the global response regulator GacA. Strain 30-84.A2 was not complemented by gacA or any cosmid from a genomic library of strain 30-84 but was complemented bygacS (formerly lemA) homologs fromPseudomonas fluorescens Pf-5 (N. Corbel and J. E. Loper, J. Bacteriol. 177:6230–6236, 1995) and Pseudomonas syringae pv. syringae B728a (E. M. Hrabek and D. K. Willis, J. Bacteriol. 174:3011–3020, 1992). Transcription ofphzR was not altered in either mutant; however,phzI transcription was eliminated in strains 30-84W and 30-84.A2. These results indicated that the GacS/GacA two-component signal transduction system of P. aureofaciens 30-84 controls the production of AHL required for phenazine production by mediating the transcription of phzI. Addition of exogenous AHL did not complement either mutant for phenazine production, indicating that the GacS/GacA global regulatory system controls phenazine production at multiple levels. Our results reveal for the first time a mechanism by which a two-component regulatory system and an AHL-mediated regulatory system interact.

Mercury (Hg) concentrations in high trophic level fish, such as bigeye tuna ( Thunnus obesus ) and yellowfin tuna ( Thunnus albacares ), can often exceed consumption advisories. Here we sampled 444 yellowfin and bigeye tuna to determine whether tuna Hg concentration varies regionally in the eastern and central Pacific Ocean and whether this variation corresponds to environmental characteristics that promote the bioavailability of Hg. Of the five regions sampled, we found significantly higher Hg concentrations in the eastern equatorial region (5°S–5°N; 110°W–120°W) for both species. Hg concentrations in this region were elevated by 0.22 and 0.17 µg·g–1for yellowfin and bigeye tuna, respectively, compared with Hg concentrations in the other regions. Tuna selenium concentrations, which may alter the toxicity of Hg, did not vary by region. Oceanographic data indicated that the eastern equatorial region had elevated chlorophyll a concentrations and shallow minimum oxygen depths, both of which promote Hg methylation. These findings suggest that methylation-promoting mechanisms may translate into regional variation in the Hg concentrations of highly mobile, high trophic level fish.

The marine form of the South American dolphin Sotalia fluviatilis has an extensive and possibly continuous distribution, from the Florianópolis region, Brazil (27°35′S, 48°34′W), north to Panama (~9°22′N, 79°54′W). The high number of records from 25–20°S is due to the presence of many observers in those latitudes. The freshwater form of this species inhabits the Amazon and Orinoco drainages. It is commonly seen in the Amazon, and has been found as far inland as southern Peru. The southern limit of the range of the marine form of Sotalia is associated with the confluence zone of the Brazil and Falkland currents, suggesting that low sea-surface temperature is a limiting factor, whereas in fresh water the distribution of Amazonian Sotalia seems more closely related to the movements and concentrated occurrence of prey.

Nutrient enrichment of surface water to the east of a shelf break front at the eastern end of Bass Strait occurs in winter. This area of enrichment is more than 100 nautical miles (E-W) by 150 nm (N-S). From east of Banks Strait (40� 45'S,148�E), some of the nutrient-rich water is carried northwards with the northward flow of Bass Strait water which later forms the well-known 'cascade' below the warmer waters of the Tasman Sea. In September 1984, the chlorophyll a concentration increased along the line of this northward flow, producing a maximum off the Victorian coast near where the cascade occurs. In contrast to nutrient and chlorophyll a distributions, zooplankton biomass (dry weight) was higher in the shallow water of Bass Strait than over the continental slope. This suggests that the plankton growth observed in shallow Bass Strait waters in late winter had ceased by September, but was continuing to the north-east and over the slope in waters with a shallow mixed depth. We propose that the northward flow of water along the shelf break maintains plankton in a nutrient-rich environment, so that they continue to grow until they are carried below the photic zone by the cascade.

Abstract. The concentrations of greenhouse gases (GHGs) like nitrous oxide (N2O) and methane (CH4) were measured in the Kerguelen Plateau Region (KPR), an area with annual microalgal bloom caused by natural Fe fertilization, which may stimulate microbes involved in GHG cycling. This study was carried out during the KEOPS 2 cruise during the austral spring of 2011. Two transects were sampled along and across the KRP, the north–south (N–S) transect (46–51° S, 72° E meridian) and the west–east (W–E) transect (66–75° E, 48.3° S latitude), both associated with the presence of a plateau, polar fronts and other mesoscale features. The W–E transect had N2O levels ranging from equilibrium (105%) to light supersaturation (120%) with respect to the atmosphere. CH4 levels fluctuated dramatically, with intense supersaturations (120–970%) in areas close to the coastal waters of Kerguelen Island and in the polar front (PF). There, Fe and nutrient fertilization seem to promote high total chlorophyll a (TChl a) levels. The distribution of both gases was more homogenous in the N–S transect, but CH4 peaked at southeastern stations of the KPR (A3 stations), where phytoplankton bloom was observed. Both gases responded significantly to the patchy distribution of particulate matter as Chl a, stimulated by Fe supply by complex mesoscale circulation. While CH4 appears to be produced mainly at the pycnoclines, N2O seems to be consumed superficially. Air–sea fluxes for N2O (from −10.5 to 8.65, mean 1.71 μmol m−2d−1), and for CH4 (from 0.32 to 38.1, mean 10.07 μmol m−2d−1) reflected sink and source behavior for N2O and source behavior for CH4, with considerable variability associated with a highly fluctuating wind regime and, in the case of CH4, due to its high superficial levels that had not been reported before in the Southern Ocean and may be caused by an intense microbial CH4 cycling.

A review of the genera Othonna and Senecio undertaken for the forthcoming Greater Cape plants 2: Namaqualand-southern Namib and western Karoo (Manning in prep.) led to a re-examination of the taxonomic status of several species. This was facilitated by the recent availability of high-resolution digital images on the Aluka website (www.aluka.org) of the Drege isotypes in the Paris Herbarium that formed the basis of many species described by De Candolle in his Prodromus systematis naturalis regni vegetabilis. These images made it possible to identify several names whose application had remained uncertain until now. Each case is briefly discussed, with citation of additional relevant herbarium specimens. The following species are reduced to synonomy: O. incisa Harv. is included in O. rosea Harv.; O. spektakelensis Compton and O. zeyheri Sond. ex Harv. are included in O. retrorsa DC.; S. maydae Merxm. is included in S. albopunctatus Bolus, which is now considered to include forms with radiate and discoid capitula; S. cakilefolius DC. is included in O. arenarius Thunb.; S. pearsonii Hutch, is included in O. aspertdus DC.; S. parvifolius DC. is included in S. carroensis DC.; S. eriobasis DC. is included in S. erosus L.f.; and S. lobelioides DC. is included in S. flavus (Decne.) Sch.Bip. The name S. panduratus (Thunb.) Less, is identified as a synonym of S. erosus L.f. and plants that are currently know n under this name should be called S. robertiifolius DC. The confusion in the application o f the names O. perfoliata (L.f.) Jacq. and O. filicaulis Jacq. is examined. O. perfoliata is lecto- typified against a specimen in the Linnaean Herbarium (LINN) w ith radiate capitula. The name O. filicaulis correctly applies to a radiate species and is treated as a synonym of O. perfoliata. The vegetatively similar taxon with disciform capitula that is currently known as O. filicaulis should be known as () undulosa (DC.) J.C.Manning Goldblatt, comb. nov. The new name O. daucifolia J.C.Manning Goldblatt is provided to replace the later homonym O. abrotanifolia (Harv.) Druce.

This paper is a review and revision of the tribe Catopocerini (Coleoptera: Leoididae: Catopocerinae) of North America. It covers the following genera: Catopocerus Motschulsky, 1870 with five species east of the Mississippi River and the resurrected genus Pinodytes Horn, 1880 with 42 species in North America west of the Mississippi River. All species in the tribe are eyeless and wingless inhabitants of forest soil and litter. Larvae and adults probably feed on subterranean fungi. Pinodytes Horn is resurrected to valid generic status. A neotype is assigned for Catopocerus politus Motschulsky. Lectotypes are designated for Catops cryptophagoides (Mannerheim, 1852) (which is transferred to Pinodytes), and Pinodytes pusio Horn, 1892. The following new synonym is recognized: Catopocerus ulkei Brown, 1933 = Catopocerus politus Motschulsky, 1870. The 33 new species and their distributions are as follows: Pinodytes angulatus (NW Oregon, USA), P. borealis (central Alaska, USA), P. chandleri (N California, USA), P. colorado (Colorado, USA), P. constrictus (S California, USA), P. contortus (E California, USA), P. delnorte (NW California, USA), P. eldorado (E California, USA), P. fresno (central California, USA), P. garibaldi (NW Oregon, USA), P. gibbosus (S California, USA), P. haidagwaii (Haida Gwaii (formerly Queen Charlotte) Islands, British Columbia, Canada), P. humboldtensis (NW California, USA), P. idaho (NW Idaho, USA), P. isabella (N Idaho, USA), P. klamathensis (SW Oregon and NW California, USA), P. losangeles (S California, USA), P. marinensis (W California, USA), P. minutus (central California, USA), P. monterey ( SW California, USA), P. newtoni (Ozarks region to E Texas, USA), P. orca (SW Oregon, USA), P. parvus (NW California, USA), P. punctatus (W Idaho and E Washington, USA), P. sanjacinto (S California, USA), P. sequoia ( S central California, USA), P. setosus ( SW Oregon and NW California, USA), P. shasta (N California, USA), P. shoshone (N Idaho, USA), P. sinuatus (SW Oregon, USA), P. spinus (N central California, USA), P. tehama (N California, USA), and P. tuolumne (E central California, USA). The following new combinations are established: Pinodytes capizzii (Hatch, 1957), ex Catopocerus; P. cryptophagoides (Mannerheim, 1852), ex Catopocerus; P. imbricatus (Hatch, 1957), ex Catopocerus; P. newelli (Hatch, 1957), ex Catopocerus; P. ovatus (Hatch, 1957), ex Catopocerus; P. pusio Horn, 1892, ex Catopocerus; P. rothi (Hatch, 1957), ex Catopocerus; P. subterraneus (Hatch, 1935), ex Catopocerus; P. tibialis (Hatch, 1957), ex Catopocerus.

ABSTRACT We have shown that a xylan-degrading bacterium, W-61, excretes multiple xylanases, including xylanase 5 with a molecular mass of 140 kDa. Here, we emend the previously used classification of the bacterium (i.e., Aeromonas caviae W-61) to Paenibacillus sp. strain W-61 on the basis of the nucleotide sequence of the 16S rRNA gene, and we clone and express the xyn5 gene encoding xylanase 5 (Xyn5) in Escherichia coli and study the subcellular localization of Xyn5. xyn5 encodes 1,326 amino acid residues, including a 27-amino-acid signal sequence. Sequence analysis indicated that Xyn5 comprises two family 22 carbohydrate-binding modules (CBM), a family 10 catalytic domain of glycosyl hydrolases, a family 9 CBM, a domain similar to the lysine-rich region of Clostridium thermocellum SdbA, and three S-layer-homologous (SLH) domains. Recombinant Xyn5 bound to a crystalline cellulose, Avicel PH-101, while an N-terminal 90-kDa fragment of Xyn5, which lacks the C-terminal half of the family 9 CBM, did not bind to Avicel PH-101. Xyn5 was cell bound, and the cell-bound protein was digested by exogenous trypsin to produce immunoreactive and xylanolytic fragments with molecular masses of 80 and 60 kDa. Xyn5 was exclusively distributed in the cell envelope fraction consisting of a peptidoglycan-containing layer and an associated S layer. Thus, Paenibacillus sp. strain W-61 Xyn5 is a cell surface-anchored modular xylanase possessing a functional cellulose-binding module and SLH domains. Possible cooperative action of multiple xylanases produced by strain W-61 is discussed on the basis of the modular structure of Xyn5.

Abstract. This work is an attempt to provide seasonal variation of biogenic NO emission fluxes in a Sahelian rangeland in Mali (Agoufou, 15.34° N, 1.48° W) for years 2004, 2005, 2006, 2007 and 2008. Indeed, NO is one of the most important precursors for tropospheric ozone, and previous studies have shown that arid areas potentially display significant NO emissions (due to both biotic and abiotic processes). Previous campaigns in the Sahel suggest that the contribution of this region in emitting NO is no longer considered as negligible. However, very few data are available in this region, therefore this study focuses on model development. The link between NO production in the soil and NO release to the atmosphere is investigated in this modelling study, by taking into account vegetation litter production and degradation, microbial processes in the soil, emission fluxes, and environmental variables influencing these processes, using a coupled vegetation–litter decomposition–emission model. This model includes the Sahelian Transpiration Evaporation and Productivity (STEP) model for the simulation of herbaceous, tree leaf and faecal masses, the GENDEC model (GENeral DEComposition) for the simulation of the buried litter decomposition and microbial dynamics, and the NO emission model (NOFlux) for the simulation of the NO release to the atmosphere. Physical parameters (soil moisture and temperature, wind speed, sand percentage) which affect substrate diffusion and oxygen supply in the soil and influence the microbial activity, and biogeochemical parameters (pH and fertilization rate related to N content) are necessary to simulate the NO flux. The reliability of the simulated parameters is checked, in order to assess the robustness of the simulated NO flux. Simulated yearly average of NO flux ranges from 2.09 to 3.04 ng(N) m−2 s−1 (0.66 to 0.96 kg(N) ha−1 yr−1), and wet season average ranges from 3.36 to 5.48 ng(N) m−2 s−1 (1.06 to 1.73 kg(N) ha−1 yr−1). These results are of the same order as previous measurements made in several sites where the vegetation and the soil are comparable to the ones in Agoufou. This coupled vegetation–litter decomposition–emission model could be generalized at the scale of the Sahel region, and provide information where few data are available.

The results of long-term studies of the vegetation of chalk outcrops of the Orenburg region (Russian Federation) and North-West Kazakhstan on Sub-Ural plateau and adjacent territories are presented. Chalk outcrops are unique botanical-geographical sites located in steppe and desert zones of Eurasia. Specific communities of calcephyte plant species have spread in these areas, in places of outcrops or close occurrence from the surface of upper-Cretaceous carbonate rocks. The flora of chalk outcrops is characterized by a great amount of rare species, mainly ende­mic, associated with peculiar substrates, the locality of habitats, and the historical past of the area of outcrops location (Matyshenko, 1985) The history of the study of flora and vegetation of chalk outcrops is given. Synthaxonomic studies of chalk vegetation as part of the ecological-floristic approach cover only territories west of the Volga river (Poluyanov, 2009; Averinova, 2011, 2016; Demina, 2014; Demina et al., 2016; Didukh et al., 2018). Chalk highlands of the North-West Kazakhstan and adjacent regions of the Russian Federation occupy quite large areas. However, up to date, there is no data on the vegetation diversity of these territories based on complete geobotanical relevés, that is why their synthaxonomy remains undeveloped. The study area with 15 massifs of chalk outcrops (Fig. 1) includes the Orenburg region (Novosergievsky, Perevolotsky, Sol-Iletskiy, Akbulak and Gaysky districts), and Aktobe (Hobdinsky, Uilsky and Bayganinsky district) and Atyrau (Zhylyoysky district) regions of the Republic of Kazakhstan. The largest massifs in the Orenburg region of the Russian Federation are: Starobelogorskie (Fig. 2), Chesnokov­skie (Fig. 3), Verkhnechibendinskie (Fig. 6), Troits­kie (Fig. 7), Pokrovskie Chalk Mountains (Fig. 4) and Durtel mountain (Fig. 5). Chalk massif Akshatau (Fig. 8) and the range Aktolagai (Fig. 9) are the largest within Aktobe region. The investigated sites are mostly located on the Sub-Ural Plateau, which extended from the southern regions of the Orenburg region to the Emba River in the territory of Aktobe region. They are less common within the Obschiy Syrt and sporadic in the Guberlinskie mountains. The study area covers a wide range of zonal vegetation from dry steppes in the northern part of the gradient to northern deserts in the southern one. The dataset includes 270 relevés of chalk outcrops communities performed by the authors in 2014–2019. The primary classification was carried out using TWINSPAN algorithm. As a result three groups of communities are established. The first group is communities of the Emben Plateau, the most southern area; second is communities on relatively developed soils in the slopes bases, depressions between chalk ridges and on their flat tops; third is widespread communities on most of the Podural Plateau and Obschy Syrt, excluding the Emben Plateau. Comparison with associations of calcephyte, semidesert and steppe vegetation (Golub, 1994; Kolomiychuk, Vynokurov, 2016; Lysenko, Yamalov, 2017; Didukh et al., 2018; Korolyuk, 2017) was made to determine the position of studied communities in the system of ecological-floristic classification of the herbasceous vegetation of Eurasia. Cluster analysis results (Fig. 10) revealed the significant specificity the chalk outcrops of the Sub-Ural Plateau in comparison with calciphytic communities of Eastern Europe, as well as with deserts and steppes zonal vegetation. That was the reason to describe a new class for vegetation of the studied chalk outcrops. The class Anabasietea cretaceae Golovanov class nov. hoc loco. Diagnostic species: Anabasis cretacea, Anthemis trotzkiana, Artemisia salsoloides, Atraphaxis decipiens,Crambe aspera, Echinops meyeri, Jurinea kirghisorum, Hedysarum tscherkassovae, Lepidium meyeri, Limonium cretaceum, Linaria cretacea, Matthiola fragrans, Nanophyton erinaceum, Seseli glabratum, Zygophyllum pinnatum;holotypus is order Anabasie­talia cretaceae ord. nov. hoc loco. Class combines calciphytic, mainly semi-shrub communities on the outcrops of chalk and marl rocks of the south of the Orenburg region and North-West Kazakhstan within the steppe (subzones of the true and desert steppes) and desert zone. The central order, Anabasietalia cretaceae Golovanov ord. nov. hoc loco, is described;holotypus is alliance Anthemido trotzkianae–Artemision salsoloidis all. nov. hoc loco. Three alliances identified within the order reflect both community distribution along the latitudinal gradient and succession stages. The alliance Sileno fruticulosae–Nanophytonion erinacei Lebedeva all. nov hoc loco is poor-species communities, located mainly on the chalk massifs in the southern part of the Sub-Ural Plateau (Emben Plateau) and adjacent territories. Holotypus of the alliance is ass. Onosmo staminei–Anabasietum cretaceae ass. nov. hoc loco with highly constant desert plant species (Anabasis salsa, Artemisia terrae-albae, Atriplex cana, Limonium suffruticosum, Rhammatophyllum pachyrhizum, etc.). It includes the ass. Onos­mo staminei–Anabasietum cretaceae ass. nov. hoc loco (Table 3, syntaxa 1–3; Tables 4–6). Holotypus hoc loco: Table 4, rel. no. 9 (YS19-034): Republic of Kazakhstan, Atyrau region, Zhylyojskij district, 10 km W Aktologay ridge, 47.48514° N, 54.97647° E, 19.05.2019, collector Yamalov S. M.) The alliance Anabasio cretaceae–Agropyrion desertorum Korolyuk all. nov hoc loco.Holotypus is ass. Agropyro desertorum–Artemisietum lessingianae ass. nov. hoc loco. Alliance includes communities in flat habitats with well-developed soils at the foot of the chalk hills in the central and northern parts of the Sub-Ural Plateau, on the chalk rock outflows, as well on their tops. Active are species of deserts and galophytic communities of the classes Artemisietea lerchianae and Festuco-Puccinellietea, as well as these of dry and desert steppes of the order Tanaceto achilleifolii–Stipetalia lessingianae. There are 2 associations: Agropyro desertorum–Artemisietum lessingianae ass. nov. hoc loco (Table 3, syntaxon 4; Table 7; fig. 23; holotypus hoc loco: Table 7, rel. no 8 (YS15-019)), Russian Federation, Orenburg region, Sol-Ilets­kiy district, Troitsk Chalk Mountains, 10 km SW vil. Troitsk, 50.65317° N, 54.542° W, 06.06.2015, collector Yamalov S. M.) and Psephello marschallianae–Artemisietum lerchianae ass. nov. hoc loco ((Table. 3, syntaxon 5; Table 8; fig. 24); holotypus hoc loco: Table 8, rel. no 15 (YS19-050), Republic of Kazakhstan, Aktyubinsk region, Hobdinsky district, chalk mountains 16 km NE vil. Zhantalap, 50.39986° N, 56.05054° N, 21.05.2019, collector Yamalov S. M.). The alliance Anthemido trotzkianae–Artemision salsoloidis Yamalov all. nov hoc loco.Holotypus is ass. Anthemido trotzkianae–Artemisietum salsoloi­dis ass. nov. Alliance includes the cenoses of the chalk highlands of the Sub-Ural Plateau (except for its extremely southern part) and the Obschiy Syrt. These are both communities of the initial and more advanced succession stages. The high constancy of Anthemis trotzkiana and Artemisia salsoloides, as well as the presence of petrophytic species widely distributed in the rocky steppes of the Southern Ural (Alyssum tortuosum, Centaurea marchalliana, Euphorbia seguieriana, Galium octonarium) are character for the alliance cenophlora. There are three associations— Nanophytono erinacei–Jurinetum kirghisori ass. nov. hoc loco (Table 3, syntaxon 6; Table 9; Fig. 25; holotypus hoc loco: Table 9, rel. no 7 (GY18-070)), Russian Federation, Orenburg region, Sol-Iletskiy district, Verhnechibendinskie Chalk Mountains, 10 km W vil. Troitsk, 50.6562° N, 54.44272° W, 07.06.2016, collector Golovanov Ya. M.); Anthemido trotzkianae–Artemisietum salsoloidis ass. nov. hoc loco (Table 3, syntaxa 7, 8; Tables 10, 11; Fig. 26; holotypus hoc loco: Table 10, rel. no 20 (GY15-047)), Russian Federation, Orenburg region, Sol-Iletskiy district, Troitsk Chalk Mountains, 10 km NW vil. Troitsk, 50.65267° N, 54.54217° E, 06.06.2015, collector Golovanov Ya. M.); Onosmo simplicissimae–Anthemietum trotzkianae ass. nov. hoc loco (Table 3, syntaxon 9; tab. 12; Fig. 27); holotypus hoc loco: Table 12, rel. no 1 (GY19-011)), Republic of Kazakhstan, Aktyubinsk region, Uilskii district, Terektytau, 10 km NE vil. Akshatau, 49.43507° N, 54.60127° E, 15.05.2019, collector — Golovanov Ya. M.). There are 2 associations in the class Festuco-Brometea. Within the dry steppe order Tanaceto achilleifolii–Stipetalia lessingianae this is Bassio prostratae–Agropyretum desertorum ass. nov. hoc loco (Table 3, syntaxa 10, 11; Table 13), holotypus hoc loco: Table 13, rel. no 8 (GY19-004)), Republic of Kazakhstan, Aktyubinsk region, Uilskii district, Terektytau, 10 km NE vil. Akshatau, 49.42942° N, 54.60047° E, 15.05.2019, collector Golovanov Ya. M.); within the true steppe order Helictotricho-Stipetalia this isass. Anthemido trotzkianae–Thymetum guberlinensis ass. nov. hoc loco (Table 3, syntaxon 12; Table 14); holotypus hoc loco: Table 14, rel. no 8 (GY14-012)), Russian Federation, Orenburg region, Gayskii district, chalk mountain Dyurtel, 4 km NE vil. Starohalilovo, 51.504° N, 58.157° E, 27.06.2014, collector Golovanov Ya. M.). The result of the research of chalk outcrops ve­getation of Sub-Ural plateau and adjacent territories is new class Anabasietea cretaceae which includes 1 order, 3 alliances, 6 associations, 3 subassociations, 2 variants and 9 facies.