Search

Copyright of Caribbean Journal of Science is the property of Caribbean Journal of Science and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The Little pocket mouse (Perognathus longimembris) encompasses 15 to 16 currently recognized subspecies, six of which are restricted to southern California and adjacent northern Baja California. Using cranial geomorphometric shape parameters and dorsal color variables we delineate six regional groups of populations from this area that we recognize as valid, but these differ in name combination and geographic range from the current taxonomy. We resurrect two names from their current placement in synonymies, synonymize two currently recognized subspecies, and we reassign a third. Importantly, we restrict the U. S. Federally endangered Pacific pocket mouse (P. l. pacificus Mearns) to the vicinity of its type locality at the mouth of the Tijuana River in the southwestern corner of San Diego County and resurrect P. l. cantwelli von Bloeker for the other two population segments along the coast, those that span the northwestern corner of San Diego County and adjacent Orange County and that in coastal Los Angeles County. The name cantwelli would now apply to the only extant populations of the Pacific pocket mouse, a reassignment with obvious management implications. Our taxonomic decisions also reconfigure the ranges of other subspecies of conservation concern, notably P. l. bangsi Mearns and P. l. brevinasus Osgood. Para el ratón de abazones menor (Perognathus longimembris) se tienen reconocidas quince o dieciséis subespecies, de las cuales seis de ellas tienen una distribución restringida al sur de California y la parte colindante del norte de Baja California. Haciendo uso de parámetros geométricos de la forma craneal y variables en la coloración dorsal, delimitamos y reconocimos como válidos seis grupos regionales de poblaciones, los cuales difieren en el nombre y área geográfica de su actual clasificación taxonómica. Reincorporamos dos nombres de las actuales sinonímias, combinamos dos subespecies que se encuentran actualmente reconocidas y reasignamos una tercera. Es importante destacar que para el ratón de abazones menor (P. l. pacificus Mearns), que se encuentra en peligro de extinción a nivel federal de E.U.A., restringimos su distribución a la vecindad de su localidad tipo en la boca del Río Tijuana, localizada en la esquina suroeste de San Diego County. Asimismo, reincorporamos a la subesepcie P. l. cantwelli von Bloeker a los otros dos segmentos de la población a lo largo de la costa, abarcando la esquina noroeste de San Diego County, colindante con Orange County y la costa de Los Angeles County. El nombre cantwelli ahora se aplicaría a las únicas poblaciones del ratón de bolsillo del Pacífico, un reasginamiento con notorias impicaciones en su manejo. Nuestras decisiones taxonómicas también incluyen la reconfiguración en los rangos de otras subespecies que son preocupantes para la conservación, como lo son P. l. bangsi Mearns y P. l. brevinasus Osgood. [ABSTRACT FROM AUTHOR]

Bare sandy flats at and below low tide level of the Wadden Sea (eastern North Sea, European Atlantic) were observed in 2020 to have been invaded by an introduced grass-like alga, Vaucheria cf. velutina (Xanthophyceae). A dense algal turf accumulated and stabilized mud, where resident seniors of the lugworm Arenicola marina had reworked rippled sand. Algae and worms were incompatible. Initially, rising patches with algal turf alternated with bare pits where lugworms crowded. Their bioturbation inhibited young algae, while the felt of established algal rhizoids clogged feeding funnels of worm burrows. Eventually, a mosaic pattern of competitors gave way to a coherent algal turf without lugworms. Concomitantly, a rich small-sized benthic fauna took advantage of the novel algal turf. This exotic Vaucheria may have the potential for drastically altering the ecological web at the lower shore. [ABSTRACT FROM AUTHOR]

The bioremediation and biomass production of organic extractive organisms (polychaetes Arenicola marina, Hediste diversicolor and halophyte Salicornia ramosissima) was assessed in an integrated multi-trophic aquaculture (IMTA) framework. Culture trials were performed outdoors using the nutient rich effluent from a shrimp farm employing recirculated aquaculture systems. Similar bioremediation efficiencies were obtained in cultures using a single polyculture tank (1 T) or two trophic levels separated tanks (2 T; ≈ 0.3 and 0.6 m2 operational area, respectively), with a reduction of 74–87% for particulate organic matter (POM), 56–64% for dissolved inorganic nitrogen (DIN) and 60–65% for dissolved inorganic phosphorus (DIP). Hediste diversicolor adapted well to culture conditions, reaching densities up to 5.000 ind. m−2 (≈ 78–98 g m−2). Arenicola marina failed to cope with water temperature that exceeded the species thermal limits, displaying a survival < 10% (20 °C often pointed as the maximum thermal threshold for this species). Productivity of S. ramosissima with 1 T was about twice that obtained with 2 T (≈ 150–170 and ≈ 60–90 g FW m−2 edible aboveground biomass, respectively). The yellowish coloration of cultured plants was likely due to the chemical oxidation and rapid sand filtration pre-treatment applied to the brackish groundwater used in the aquaculture facility, that removed iron (and probably other essential elements). Overall, 1 T design combining H. diversicolor and S. ramosissima displayed the best bioremediation performance and biomass production, while also allowing reducing in half the operational area required to implement this IMTA framework. [ABSTRACT FROM AUTHOR]

Bioturbating organisms contribute significantly to elemental cycling in sediments through burrowing, grazing, organic matter and altering porewater chemical conditions. In the process, organisms are known to produce copious amounts of faecal material at high rates, sometimes in excess of 1 000 000 kg day−1 in a 1 km2 area. Material from three organisms (Arenicola marina, Callichirus major and Diopatra cuprea) was collected from two locations, Raccoon Key and Steamboat Pass, in the Ogeechee River estuary, Georgia, USA, to explore how faecal production affects organic carbon cycling and clay mineralogies. The individual organisms' feeding strategies played a strong role in the extent to which they concentrate organic matter and lead to the formation of clay minerals. The faecal material of filter feeding Diopatra cuprea and selective deposit feeding Callichirus major contains up 45.8% and 47.3% kaolinite, respectively, while kaolinite is below detection limits in the surrounding matrix. By contrast, the non‐selective deposit‐feeder Arenicola marina does not appear to form or concentrate clay minerals. Callichirus major increases organic carbon contents at Raccoon Key by 68‐fold and Diopatra cuprea increases total organic carbon (w/w%) by 119‐fold and 32‐fold at Raccoon Key and Steamboat Pass, respectively. Arenicola marina, in contrast, does not noticeably concentrate organic matter in its faecal material, most likely as a consequence of non‐selective deposit‐feeding. Potentiometric titration data was used to explore surface reactivity and metal sorption. Diopatra cuprea and Callichirus major faecal material has strong metal binding affinities relative to the surrounding matrix, thereby increasing the potential for trace metals to be sequestered into the sedimentary record. The widespread occurrence of invertebrate faecal material enriched in clay minerals and organic matter likely has a significant influence on organic matter, grain size and trace metal distribution in estuarine sediments. [ABSTRACT FROM AUTHOR]

To facilitate development of tailored management strategies for bait species within Knysna Estuary (South Africa), demand for bait, harvesting activity and perceptions around conservation among recreational and subsistence bait fishers were investigated. In 2015 and 2016, bait collectors were interviewed (n = 84) and observed (n = 167) during low tides at six sites during peak and off-peak holiday periods. Significant associations among subsistence and recreational fishers and their favoured bait species, collecting spots and method, frequency of collection, views on regulations and desired daily limit for mudprawns suggest differences that may warrant different management strategies. Furthermore, observed methods and duration of bait collecting differed according to site, suggesting spatial variation in baiting pressures. Subsistence fishers potentially collect more mudprawns more frequently than do recreational fishers and consequently have a greater impact on mudprawn populations. By contrast, recreational fishers collect more polychaete worms, but because they are mainly active during holidays, their impact on these species may be localised and not yet critical. Most subsistence fishers would like increased daily bag limits, to sell bait and would welcome a rotational zonation scheme to replace the current permanent exclusion zone. The merits and disadvantages of these management options and suggestions are discussed. [ABSTRACT FROM AUTHOR]

Copyright of Revista Mexicana de Biodiversidad is the property of Universidad Nacional Autonoma de Mexico, Instituto de Biologia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Coprinellus phaeoxanthus A.R.Gomes & Wartchow is described as a new species and is characterised by cordiform basidiospores similar to those of the recently described Coprinellus arenicola. However, it differs in the presence of voluminous pleurocystidia in the velar elements, which are shorter than in Coprinellus arenicola , and in the lack of clamp connections. In addition, exsiccatae of a Brazilian collection identified as ' Coprinus xerophilus ' are analysed, and because of the star-shaped velar patch on the pileus and the non-volvate stipe base, it is considered to be the same as Coprinus calyptratus , representing a new record from South America. [ABSTRACT FROM AUTHOR]

The proximate composition and mineral contents of Stichopus horrens and Holothuria arenicola from Chabahar Bay were analyzed and investigated. During the present study, we aimed to demonstrate the nutritive value. The approximate percent composition of moisture, protein, fat, and ash were 92.8, 3.47, 0.4, and 3.33% in S. horrens and 93, 4.4, 0.6, and 2% in H. arenicola, respectively. Atomic absorption spectrophotometry of the ashes indicated the body wall of two species of sea cucumbers contained higher amounts of both macro minerals (92.5 mg/100 g Mg in S. horrens and 115 mg/100 g Mg in H. arenicola; 106.25 mg/100 g Ca in S. horrens and 83.25 mg/100 g Ca in H. arenicola) and trace elements (521.781 mg/100 g Fe in S. horrens; 60.354 mg/100 g Fe in H. arenicola, and 0.096 mg/100 g Zn in S. horrens; 0.04 mg/100 g Zn in H. arenicola). For both species, there were high content of protein and essential mineral. Also, they have low content of fat in the body wall of two species in the experiment. [ABSTRACT FROM AUTHOR]

We evaluated geographic variation and subspecific taxonomy in the Le Conte's thrasher Toxostoma lecontei by analyzing DNA sequences from 16 nuclear loci, one mitochondrial DNA locus, and four study skin characters, and compared these data sets with previously published data on plumage coloration and different mtDNA genes. Morphological support for the southernmost taxon, T. l. arenicola, is relatively weak: multivariate analyses of morphometrics or back coloration do not provide diagnostic support, although one color character differs statistically. However, combined DNA analyses indicate that T. l. arenicola is diagnosable and reciprocally monophyletic, diverging from T. l. lecontei at least 140 000 yr ago. Little to no past introgression across a very short geographic distance despite the long period of isolation is strong evidence of independently evolving taxa. We suggest that the lack of morphological divergence in traits related to niche use has prevented the two taxa from invading each other's range. Despite relatively weak morphological differences we suggest that these two deeply divergent lineages merit species status, and we suggest Vizcaíno thrasher for the common name corresponding to T. l. arenicola. The population size of T. l. arenicola is small and the taxon is in need of preservation attention. [ABSTRACT FROM AUTHOR]

Robust evidence of fisheries impacts is required to support evidence-based management. Intertidal fisheries have received considerably less attention to date compared to inshore and offshore counterparts. The need for additional intertidal data and assessment has been identified for protected sites under UK legislation (i.e., the Department for Environment, Food & Rural Affairs 'revised approach to commercial fisheries'). Digging for Arenicola spp. is carried out both recreationally and commercially within the Berwickshire and North Northumberland Special Area of Conservation (SAC), a Marine Protected Area (MPA) along the northeast coast of England. This study investigated the impacts of such activities, comparing sites across a gradient of fishing pressure (none, low, high), in combination with small scale experimental disturbances (simulated digging and lugworm exclusion) at an unfished site. Fishing pressure gradient studies indicated no long-term impacts on the target species, as no significant differences were detected between sites. This suggests that current collection intensities are not reducing or altering targeted lugworm populations. However, finer scale experimental work revealed significant negative impacts upon the wider sediment communities in the short term, which was mirrored in the longer-term, fisheries scale gradient site comparisons. Reductions in total infaunal abundance and taxonomic richness and altered community structures were observed. Recovery within experimental plots was rapid (within a few months), suggesting that under similar conditions, sites have the potential for substantial recovery if disturbance is ceased. The observed alterations to infaunal communities could have ecosystem wide implications, with altered functional diversity and ecosystem processes that are not compatible with the conservation objectives or designations of the study site. Additional management measures such as further closed areas or seasonal closures to bait digging would allow for recovery and restoring sites. • Investigating impacts of bait digging on the target species and associated infauna. • Comparative and experimental studies combined. • Impacts on lugworms were not discernible against natural background variability. • Negative impacts observed on the infaunal community (abundance, richness, community). [ABSTRACT FROM AUTHOR]

Porewater profiles and sediment-water fluxes of oxygen, nutrients, pH, calcium, alkalinity, and sulfide were measured in intertidal sandflat sediments from the Oosterschelde mesotidal lagoon (The Netherlands). The influence of bioturbation and bioirrigation by the deep-burrowing polychaete Arenicola marina on the rates and sources of benthic alkalinity generation was examined by comparing measurements in intact and defaunated sediment cores before and after the addition of A. marina in summer and fall 2011. Higher organic matter remineralization rates, shallower O 2 penetration, and greater sediment-water solute fluxes were observed in summer, consistent with higher sediment community metabolic rates at a higher temperature. Lugworm activity stimulated porewater exchange (5.1 × in summer, 1.9 × in fall), organic matter remineralization (6.2 × in summer, 1.9 × in fall), aerobic respiration (2.4 × in summer, 2.1 × in fall), alkalinity release (4.7 × in summer, 4.0 × in fall), nutrient regeneration, and iron cycling. The effects of lugworm activity on net sediment-water fluxes were similar but more pronounced in summer than in fall. Alkalinity release in fall was entirely driven by metabolic carbonate dissolution, while this process explained between 22 and 69% of total alkalinity production in summer, indicating the importance of other processes in this season. By enhancing organic matter remineralization and the reoxidation of reduced metabolites by the sediment microbial community, lugworm activity stimulated the production of dissolved inorganic carbon and metabolic acidity, which in turn enhanced metabolic CaCO 3 dissolution efficiency. In summer, evidence of microbial long distance electron transport (LDET) was observed in defaunated sediment. Thus, alkalinity production by net carbonate dissolution was likely supplemented by anaerobic respiration and LDET in summer. [ABSTRACT FROM AUTHOR]

Abstract: Ecological network analysis (ENA) was used to study the effects of Pomatoschistus microps on energy transport through the food web, its impact on other compartments and its possible role as a keystone species in the trophic webs of an Arenicola tidal flat ecosystem and a sparse Zostera noltii bed ecosystem. Three ENA models were constructed: (a) model 1 contains data of the original food web from prior research in the investigated area by Baird et al. (2007), (b) an updated model 2 which included biomass and diet data of P. microps from recent sampling, and (c) model 3 simulating a food web without P. microps. A comparison of energy transport between the different models revealed that more energy is transported from lower trophic levels up the food chain, in the presence of P. microps (models 1 and 2) than in its absence (model 3). Calculations of the keystone index (KSi) revealed the high overall impact (measured as εi ) of this fish species on food webs. In model 1, P. microps was assigned a low KSi in the Arenicola flat and in the sparse Z. noltii bed. Calculations in model 2 ranked P. microps first for keystoneness and εi in both communities, the Arenicola flat and the sparse Z. noltii bed. Taken together, our results give insight into the role of P. microps when considering a whole food web and reveal direct and indirect trophic interactions of this small-sized fish species. These results might illustrate the impact and importance of abundant, widespread species in food webs and facilitate further investigations. [Copyright &y& Elsevier]

Streptomyces antibiotic regulatory proteins (SARP) normally play positive regulatory roles during streptomyces antibiotics biosynthesis. sare4854, a gene in Salinispora arenicola CNH643 DSM 44819 was proposed to encode a SARP. Here, sare4854 was expressed in a heterolohous system for functional characterization. However, the antibiotic production in resultant strain was repressed significantly. Bioinfomatic analysis showed that sare4854 has an additional nucleoside triphosphate hydrolases (NTPase) domain at the C-terminus, besides a SARP-like domain (DBD: DNA binding domain and BTA: bacterial transcnptional activation domain) at the N-terminus conserved in all SARPs. The possible mechanism of sare4854 in antibiotic synthesis in this abnormal phenomenon was discussed here. [ABSTRACT FROM AUTHOR]

Type specimens or original specimens of 15 taxa in Coltricia and Coltriciella described by Corner from Southeast Asia were examined. Among these taxa, ten names were published invalidly because no type was designated in the original publication. The following two names are accepted in the original genus: Coltricia hirtipes and C. strigosipes. Two new species, Inonotus parvulus and I. magnus, are described. Validating descriptions are given for the following five species: Coltricia albidipes, C. arenicola, C. kinabaluensis, C. progressus, and Coltriciella corticicola. The original materials of C. grandis, C. gracilipes, and C. hirtipes var. pleuropodalis are, respectively, identical to Coltricia crassa, C. pyrophila, and C. minor. In addition, C. subfastosa seems to be Pyrrhoderma adamantinum, although no basidiospores were found in the type specimen. Illustrated descriptions of eight species are given. [ABSTRACT FROM AUTHOR]

The paper reports 23 rare and noteworthy Bulgarian larger fungi including the confirmation of the presence of Paxillus rubicundulus in the country and the second records of Cantharellus pallens, Crinipellis mauretanica, Ditiola peziziformis, Geopora arenicola, Laccaria proxima, Marasmius collinus and Pterula multifida. Brief descriptions are provided for Cantharellus pallens, Ditiola peziziformis, Geopora arenicola, Gymnopus quercophilus, Marasmius collinus, and Paxillus rubicundulus based upon the Bulgarian specimens. Geopora arenicola, Trichoglossum hirsutum var. hirsutum, Cantharellus amethysteus, C. pallens, Laccaria proxima and Paxillus rubicundulus are illustrated. In addition, new collections of some threatened, rare and less known species are also included. [ABSTRACT FROM AUTHOR]

ABSTRACT. During faunistic study on psammophilic ciliates along the coast of Qingdao, China, a population of Trachelocerca arenicola Kahl, 1933 was found and then investigated using silver staining and gene sequencing methods. The results indicated that it represented a new genus Apotrachelocerca characterized by uninterrupted circumoral kineties composed of two rows of dikinetids and no brosse or ciliary tuft in the oral cavity. This new genus should be assigned to the family Prototrachelocercidae Foissner, 1996. Based on the small subunit rRNA gene sequence, phylogenetic trees revealed that Apotrachelocerca arenicola occupied a basal position to other trachelocercids. [ABSTRACT FROM AUTHOR]

Abstract: In order to investigate the residues associated with binding of the substrate taurocyamine in Arenicola mitochondrial taurocyamine kinase (TK), we performed Ala-scanning of the amino acid sequence HTKTV at positions 67–71 on the GS loop, and determined apparent K m and V max (appK m and appV max, respectively) of the mutant forms for the substrates taurocyamine and glycocyamine. The appK m values for taurocyamine of the K69A, T70A and V71A mutants were significantly increased as compared with wild-type, suggesting that these residues are associated with taurocyamine binding. Of special interest is a property of V71A mutant: its catalytic efficiency for glycocyamine was twice that for taurocyamine, indicating that the V71A mutant acts like a glycocyamine kinase, rather than a TK. The role of the amino acid residue K95 of Arenicola MiTK was also examined. K95 was replaced with R, H, Y, I, A and E. K95R, K95H and K95I have a 3-fold higher affinity for taurocyamine, and activity was largely lost in K95E. On the other hand, the K95Y mutant showed a rather unique feature; namely, an increase in substrate concentration caused a decrease in initial velocity of the reaction (substrate inhibition). This is the first report on the key amino acid residues responsible for taurocyamine binding in mitochondrial TK. [Copyright &y& Elsevier]

Abstract: Biogeographic change in response to climate is a ratchet-like process, with gradual long term change punctuated by advances and retreats caused by extreme events. The winter of 1962–63 was the coldest winter since 1740, and caused lasting widespread changes in intertidal populations in Europe. Against the background of several decades of gradual warming, the severely cold winter of 2009–10 provided an opportunity to test mechanistic hypotheses regarding the control of biogeographic limits, including recruitment failure and adult mortality. As a result of enhanced recruitment in cold conditions, the northern barnacle Semibalanus balanoides expanded its range in both France and Iberia at an average rate of 25kmyear−1. The northern polychaete Arenicola marina had high recruitment in northern France, which filled in a gap in its range in the central English Channel. The southern barnacles Chthamalus montagui and Chthamalus stellatus, which are sensitive to cold winters, suffered recruitment failure but no adult mortality at their northern limit in continental Europe. The southern limpet, Patella rustica and the southern polychaete Diopatra which are sensitive to cold summers, had virtually no change in distribution, as a result of the prior warm summer. The southern mussel Mytilus galloprovincialis suffered little adult mortality at its northern limit in continental Europe. Metapopulation models of future distribution, based on these mechanisms, and validated by hindcasts of historical biogeography, indicate that a regime shift will occur in northern Europe as southern species like Diopatra are able to invade the English Channel and from there enter the North Sea. These models and the historical biogeographic record confirm the view that biogeographic change is punctuated by population responses to extreme events. [Copyright &y& Elsevier]

Abstract: Eight new species of the African Restionaceae (Restionoideae) are described, viz.: Cannomois anfracta, Cannomois arenicola, Cannomois grandis, Nevillea vlokii, Thamnochortus kammanassiae, Willdenowia pilleata, Restio uniflorus and Restio mkambatiae. A key to the species of Cannomois is provided, as well as a table comparing the characters of the three species in Nevillea. For all new species, notes on the affinities of the species and their habitats are provided. Two new combinations, Cannomois primosii (Pillans) H.P. Linder and Cannomois robusta (Kunth) H.P. Linder, are made. [Copyright &y& Elsevier]

Eleven isolates of Mycobacterium species as well as an antimycobacterial Salinispora arenicola strain were cultured from the sponge Amphimedon queenslandica. The 16S rRNA, rpoB, and hsp65 genes from these Mycobacterium isolates were sequenced, and phylogenetic analysis of a concatenated alignment showed the formation of a large clade with Mycobacterium poriferae isolated previously from another sponge species. The separation of these Mycobacterium isolates into three species-level groups was evident from sequence similarity and phylogenetic analyses. In addition, an isolate that is phylogenetically related to Mycobacterium tuberculosis was recovered from the sponge Fascaplysinopsis sp. Several different mycobacteria thus appear to co-occur in the same sponge. An actinobacterium closely related to S. arenicola, a known producer of the antimycobacterial rifamycins, was coisolated from the same A. queenslandica specimen from which mycobacteria had been isolated. This Salinispora isolate was confirmed to synthesize rifamycin and displayed inhibitory effects against representatives from two of three Mycobacterium phylotype groups. Evidence for antagonism of sponge-derived Salinispora against sponge-derived Mycobacterium strains from the same sponge specimen and the production of antimycobacterial antibiotics by this Salinispora strain suggest that the synthesis of such antibiotics may have functions in competition between sponge microbial community members. [ABSTRACT FROM AUTHOR]

Saliniketals A and B are unusual polyketides from the marine actinomycete Salinispora arenicola that inhibit ornithine decarboxylase induction. The structural similarities between the saliniketals and the ansa chain of the potent rifamycin antibiotics, which co-occur in the fermentation broth, suggest a common origin between the two compound classes. Using PCR-directed mutagenesis, chemical complementation studies, and stable isotope feeding experiments, we showed that the saliniketals are byproducts of the rifamycin biosynthetic pathway diverging at the stage of 34a-deoxyrifamycin W. Our results suggest that a single enzyme, the cytochrome P450 monooxygenase encoded by sare1259, catalyzes multiple oxidative rearrangement reactions on 34a-deoxyrifamyin W to yield both the saliniketal and rifamycin structural classes. [ABSTRACT FROM AUTHOR]

The benthic microbial food web can be responsible for a large proportion of benthic carbon cycling yet there are few data on the trophic interactions between this food web and macrobenthos. A large-scale field experiment was conducted to investigate effects of eliminating the polychaete Arenicola marina on benthic microbes (prokaryotes, heterotrophic and autotrophic protists) and metazoan meiofauna in a marine intertidal flat of the North Sea, Germany. Over a period of 2 years, quantity and composition of micro- and meiobenthos from unmanipulated sites were compared to those from sites deplete of lugworms. These grazer treatments were cross-classified with different sediment characteristics (low- and mid-intertidal areas). Lugworm removal resulted in an initial increase in abundance of prokaryotes and nanoflagellates, which became less pronounced in the second year. Ciliates were not affected quantitatively, but in the absence of lugworms, diversity and the proportion of carnivorous forms increased. Meiobenthos (nematodes, ostracods and copepods) were affected only moderately. The observed changes are probably due to a combination of release from grazing/predation pressure, changes in the species composition of higher trophic levels (namely large polychaetes) and altered environmental conditions (such as depth of the oxygenated layer and sediment grain size). Spatial differences between sites of different tidal exposure/grain size appeared to be as large as temporal differences during the 2 years following the manipulation of the system. We conclude that in intertidal sediments, indirect effects due to habitat transformation are as important as direct biological interactions (grazing pressure and competition) for the dynamics of the benthic microbial food web. [ABSTRACT FROM AUTHOR]

Standard microelectrode technique was used to study electrical activity of the isolated heart of the polychaete annelid, Arenicola marina. Typical pacemaker activity with slow diastolic depolarization was observed in all recordings. The average maximum diastolic potential (−58.4 ± 3.2 mV), the average amplitude of the action potential (28.7 ± 4.7 mV) and the average total duration of the action potential (2,434 ± 430 ms) were determined. There has been no gradient of automaticity observed in our studies, which suggests that all regions of the Arenicola heart could possess pacemaker functions. Acetylcholine (ACh) produced a concentration dependent (5 × 10−8–5 × 10−5 M) increase of the beating rate via increase in the rate of the diastolic depolarization. ACh (5 × 10−5 M) increased beating rate by 2.5-fold compared to the control rate. A stronger action of ACh resulted in depolarization, block of action potential generation and contracture of the heart. The non-hydrolysable ACh analog carbacholine (10−8–10−6 M) produced similar effects. All effects of ACh and carbacholine were abolished by 5 × 10−6 M atropine. d-Tubocurarine (5 × 10−5 M) did not significantly alter effects of ACh or carbacholine. Epinephrine (10−8–10−6 M) caused the slowing of pacemaker activity and marked decrease of action potential duration. 10−6 M epinephrine produced complete cardiac arrest. The effects of epinephrine were not significantly altered by the β-blocker propranolol (5 × 10−6 M). The β-agonist isoproterenol (10−7–10−5 M) and the α-agonist xylometazoline (10−6–10−5 M) did not produce significant effects. Thus, cholinergic effects in the Arenicola heart are likely to be mediated via muscarinic receptors, while the nature of adrenergic effects needs further investigation. [ABSTRACT FROM AUTHOR]

The taxonomic composition of marine mycelial fungi was determined in the interstitial habitats of the Vostok Bay littoral (Peter the Great Bay, the Sea of Japan). A total of 39 species of ascomycetes and anamorphic fungi were detected and identified. The predominant species of the intertidal zone were Corollospora maritima, C. lacera, Carbosphaerella leptosphaerioides, Arenariomyces trifurcatus ( Ascomycota), Alternaria alternata, Scolecobasidium arenarium, and Zalerion maritimum (anamorphic fungi). The complete list of species of obligately marine ascomycetes and anamorphic fungi from the interstitial habitats of the Vostok Bay littoral is presented for the first time [ABSTRACT FROM AUTHOR]

Where, since the 1980s, patchy and variable green algal mats are prevailing, distinct belts of an amphipod ( Corophium volutator) and seagrass ( Zostera spp.) had dominated in the 1930s. The zonation between tide marks has been mapped in a sheltered sedimentary bay in the Wadden Sea near the island of Sylt (coastal eastern North Sea). Maps on vegetation from 1924 and on selected macrobenthos from 1932 and 1934 are compared with biannual surveys conducted from 1988 to 2006. Rising high water levels and eutrophication are suggested to be major causes of the observed long-term changes. In front of a saltmarsh, a sandy beach developed and partly displaced former cyanobacterial mats. Advancing sandiness may have inhibited C. volutator and facilitated lugworms, Arenicola marina, in the upper tidal zone. A variable occurrence of green algal mats arising in the 1980s affected infauna and seagrass by smothering the biota underneath. This dissolved a coherent belt of Zostera noltii. In the lower tidal zone, natural disturbances had lasting effects on the occurrence of mussels with attached fucoid algae. The spectrum of species became enriched by alien species (13% of macrobenthic taxa). A reversal to habitat structure and biotic zonation of the 1920-1930s does not seem possible. Aliens, in combination with climate change, are expected to further divert the ecological pattern to new configurations. [ABSTRACT FROM AUTHOR]

Arenicolsterol A (ASA), a novel cytotoxic enolic sulphated sterol, was isolated from the marine annelid, Arenicola cristata (AC). Growth inhibition of this compound on cancer cell lines was determined by MTT assay and suppression of tumour stem cells colony formation. The results showed that ASA was selectively cytotoxic on HeLa cell line (IC50 = 6.00 ± 1.16 μmol L- 1 on HeLa cell line, IC50 = 10.85 ± 0.97 μmol L- 1 on 929 cell line and 14.72 ± 1.55 μmol L- 1 on NCI-h6 cell line). In addition, the apoptosis induced by ASA was verified from monitoring the stainability with Annexin V and propidium iodine by a fluorescence-activated cell sorter. The experimental data confirmed that ASA could induce apoptosis in HeLa cells by arresting early stage in apoptosis. Meanwhile, the apoptosis was found to be correlative with the inhibition of the protein tyrosine phosphatases (cdc25A, cdc25B, JSP1, etc). Therefore, ASA might be a novel promising precursor of anticancer medicines. [ABSTRACT FROM AUTHOR]

Since the introduction of the term ecosystem engineering by Jones et al. many studies have focused on positive, facilitative interactions caused by ecosystem engineering. Much less emphasis has been placed on the role of ecosystem engineering in causing negative interactions between species. Here, we report on negative interactions between two well known ecosystem engineers occurring at the interface of salt marsh and intertidal flat (i.e. common cordgrass Spartina anglica and lugworms Arenicola marina), via modification of their joint habitat. A field survey indicated that, although both species share a common habitat, they rarely co-occur on small spatial scales (<1 m). Experiments in the field and in mesocosms reveal that establishment of small Spartina plants is inhibited in Arenicola-dominated patches because of low sediment stability induced by the lugworms. In turn, Arenicola establishment in Spartina-dominated patches is limited by high silt content, compactness and dense rooting of the sediment caused by Spartina presence. Our results show that negative interactions by modification of the environment can result in rapid mutual exclusion, particularly if adverse effects of habitat modification are strong and if both species exhibit positive feedbacks. This illustrates the potential for negative interactions via the environment to affect community composition. [ABSTRACT FROM AUTHOR]