(Table 1) Dinoflagellate cysts and acritarchs in upper Pliocene and Pleistocene sediments from ODP Hole 151-911A

Pliocene and Pleistocene sediments from Ocean Drilling Program Leg 151, Hole 911 A, drilled on the innermost Yermak Plateau (Eastern Arctic Ocean), were studied for their dinoflagellate cyst content. Three assemblage zones were tentatively defined, characterized by the predominance of few species. The composition of the assemblages changed markedly, even within single assemblage zones, during the last 2.6 to 2.8 m.y., reflecting the variable influence of warmer water from the Norwegian Sea, fluctuations in the influence of cold polar water masses, and the extent of sea-ice cover. Polar to subpolar surface water masses prevailed on the Yermak Plateau during the late Pliocene, when the eastern Arctic Ocean was probably isolated from the Norwegian-Greenland Sea. Intrusions of warmer water are recorded since the latest Pliocene, alternating with colder periods and a prolonged seasonal sea-ice cover. The composition of the dinoflagellate cyst assemblages has also changed considerably since the middle Pleistocene, reflecting the establishment of stronger fluctuations in surface water mass conditions than before at Yermak Plateau.

Dinoflagellate cyst records from the East Greenland continental margin

Late Weichselian and Holocene dinoflagellate cyst assemblages have been investigated at two stations situated close to the modern Polar Front at the continental margin oft East Greenland. Both the concentrations of dinoflagelate cysts and the assemblage composition reflect changes in the surface water conditions, occurring in distinct steps during the past 15,000 years. Low concentrations of dinoflagellate cysts during Termination Ia suggest harsh environmental conditions, most probably caused by an extensive sea-ice cover and/or a high influx of low salinity meltwater. A surface water warming was recorded from 13,000 - 12,000 years BP, related to the inflow of warmer water trom the North Atlantic into the western Norwegian-Greenland Sea. The interval between Terminations la and Ib was characterized by a strong seasonality with an extensive sea-ice cover in winter and relatively warm surface waters in summer. At the transition to the Holocene, a reorganisation of the hydrography resulted in surface water conditions characteristic for the Holocene with three well-defined major water masses and oceanographic fronts The modern water mass conditions at both stations were established at the end of Termination Ib, around 6,400 to 6,800 years BP. In general, the influence of colder surface waters was more pronounced at the location off Scoresby Sund throughout the Holocene. Arctic water had the strongest influence at both stations in the middle Holocene. A progressive cooling with an increase in sea-ice cover is time-transgressivelyrecorded at both stations during the Holocene, indicating that the Polar Front moved to its present position or that branches of the zonal currents expanded from the East Greenland shell eastward during tlie last 3,000 years.

Biological Atlas of the Arctic Seas 2000: Physical oceanography, hydrochemistry, meteorology, and plankton of the Barents and Kara Seas

Presented are physical and biological data for the region extending from the Barents Sea to the Kara Sea during 158 scientific cruises for the period 1913-1999. Maps with the temporal distribution of physical and biological variables of the Barents and Kara Seas are presented, with proposed quality control criteria for phytoplankton and zooplankton data. Changes in the plankton community structure between the 1930s, 1950s, and 1990s are discussed. Multiple tables of Arctic Seas phytoplankton and zooplankton species are presented, containing ecological and geographic characteristics for each species, and images of live cells for the dominant phytoplankton species.

Dinoflagellate cyst abundances at DSDP Site 94-607 from the North Atlantic (Appendix B)

The climatic deterioration related to the onset of Northern Hemisphere glaciations (circa 2.52 Ma BP) must have lead to reorganization and relocation of species associations and may have enhanced species turnover. The present study investigates how this deterioration affects the dinoflagellate cyst and acritarch assemblages from two locations, DSDP Site 607 (North Atlantic) and the Singa section (southern Italy). The records from these locations cover the interval from 2.8 to 2.2 Ma with at least a 5 ka resolution and they have been correlated to the Milankovitch periodicities on a cycle to cycle basis by means of integrated high resolution stable isotope, calcium carbonate, foraminiferal, palynological and magnetostratigraphical datasets. In the present study this high resolution stratigraphic framework is used for a detailed correlation of events occurring in each of the depositional sequences. It also enables further assessment of the palaeoenvironmental preferences of some dinoflagellate cyst forms. Comparison of the two palynological records reveals a close correspondence in the timing of major assemblage changes and extinction events, confirming their Milankovitch cycle based correlation. A close link between periods of Northern Hemisphere cooling (at oxygen isotope stages 110, 104 and 100-96) and increased dinoflagellate cyst turnover appears to be present for both DSDP Site 607 and the Singa section. The turnover events can also be recognized in the records of planktic foraminifera and calcamous nannoplankton. Comparison of the Singa section with Site 607 and with other time equivalent marine palynological data sets, shows that some oceanic taxa respond similarly over a large area. The biostratigraphical implications are discussed. Notably the last occurrence of Invertocystu lucrymosa appears to be a valuable marker for isotope stage 110 in the Mediterranean and North Atlantic.

Dinoflagellate cyst species composition of recent surface samples (Appendix)

Dinoflagellate cysts and other organic-walled microfossils have been studied in recent surface sediments from the entire Norwegian-Greenland Sea. More than 30 taxa have been recognized, of which only few show a distinct distribution pattern, and allow description of four assemblages. The occurrence of most taxa is related to the relatively warmer waters of the Norwegian Sea. Algidaspaeridium? minutum s.1., Brigantedinium simplex and Impagidinium? pallidum are the only species showing a preference for colder water masses. Two species, I.? pallidum and Nematosphaeropsis labyrinthus are mainly restricted to the oceanic environment, whereas the other species have also been reported from neritic environments in previous studies. Due to the limited knowledge of the ecological and sedimentological factors influencing the occurrence of dinoflagellate cysts in oceanic environments, their distribution in recent sediments can be only related to surface water masses in a broad sense. Although the distribution of assemblages correlates with specific surface water masses, comparison with assemblages recovered from sediment traps deployed basinwide in the Norwegian-Greenland Sea (Dale and Dale, 1992) revealed some major discrepancies in species composition and percentage abundances. The differences cannot be explained with certainty at the moment, although there is some evidence that transport of dinoflagellate cysts and other fossilizable microplankton in water masses by currents, in sea-ice and sediments may modify the assemblages found in recent oceanic surface sediments from the Norwegian-Greenland Sea.

Geographic distribution of dinoflagellate cysts in surface sediments

Dinoflagellate cysts are useful for reconstructing upper water conditions. For adequate reconstructions detailed information is required about the relationship between modern day environmental conditions and the geographic distribution of cysts in sediments. This Atlas summarises the modern global distribution of 71 organicwalled dinoflagellate cyst species. The synthesis is based on the integration of literature sources together with data of 2405 globally distributed surface sediment samples that have been preparedwith a comparable methodology and taxonomy. The distribution patterns of individual cyst species are being comparedwith environmental factors that are knownto influence dinoflagellate growth, gamete production, encystment, excystment and preservation of their organic-walled cysts: surface water temperature, salinity, nitrate, phosphate, chlorophyll-a concentrations and bottom water oxygen concentrations. Graphs are provided for every species depicting the relationship between seasonal and annual variations of these parameters and the relative abundance of the species. Results have been compared with previously published records; an overview of the ecological significance as well as information about the seasonal production of each individual species is presented. The relationship between the cyst distribution and variation in the aforementioned environmental parameters was analysed by performing a canonical correspondence analysis. All tested variables showed a positive relationship on the 99% confidence level. Sea-surface temperature represents the parameter corresponding to the largest amount of variance within the dataset (40%) followed by nitrate, salinity, phosphate and bottom-water oxygen concentration, which correspond to 34%, 33%, 25% and 24% of the variance, respectively. Characterisations of selected environments as well as a discussion about how these factors could have influenced the final cyst yield in sediments are included.

Dinoflagellate cyst accumulation rates of ODP Hole 146-893A from Santa Barbara Basin

The dinoflagellate cyst record from Ocean Drilling Program Hole 893A, Santa Barbara Basin, southern California, is examined at millennial-scale resolution for the past 40 kyr. Changes in cyst abundance, composition of cyst assemblages, and their diversity reflect major shifts in climate and ocean circulation in the region over this time interval. Throughout the sequence, dinoflagellate cyst assemblages are dominated by heterotrophic dinoflagellates. Brigantedinium spp. and other upwelling-related taxa such as Echinidinium and Protoperidinium americanum are abundant, indicating the continued influence of coastal upwelling on the basin during the late Quaternary. A significant increase in cyst accumulation rates is seen during the Holocene and, to a lesser extent, during shorter warming events such as Bolling/Allerod and Dansgaard-Oeschger interstadials, implying enhanced marine productivity during these periods. Cyst diversity is high during the Holocene. An increase in abundance of cysts produced by autotrophic dinoflagellates in the late Holocene suggests enhanced input of warm, nutrient-rich waters. In contrast, cyst assemblages from the Last Glacial Maximum exhibit a relatively low diversity and an increase in the cysts of heterotrophic dinoflagellates, in particular Selenopemphix nephroides. The presence of this taxon in association with Brigantedinium spp. implies substantial cooling of surface waters in the Santa Barbara Basin at that time.

(Table 2) Dinoflagellate cysts in surface sediment samples of METEOR cruises M20/2, M23/1, M34/2 and M34/2

The organic walled cyst content of 41 surface sediment samples from the south-eastern South Atlantic Ocean have been studied to create a dataset that can be used for palaeoceanographic reconstructions. In order to obtain insight into which environmental factors influence the distribution of individual cyst species, the cyst associations have been compared with oceanographic characteristics of the overlying water masses, i.e. temperature, salinity, density and stratification gradients. The associations and relationships have been established by visual examination of the dataset and the multivariate ordination techniques, Detrended Correspondence Analysis and Canonical Correspondence Analysis. Special attention has been given to the factors of transport and preservation of the cysts. Five associations have been recognised as being characteristic of (1) areas influenced by coastal upwelling and/or river outflow, (2) open ocean, (3) Agulhas Current and southern Benguela Current, (4) Benguela Current and (5) Walvis Bay, shelf break area. The factors dominant in influencing either directly or indirectly the cyst distributions appear to be the stratification in the upper 50 m of the water column, nutrient concentration and seasonality. Variations in sea surface temperatures and salinities have only minor effect on cyst distribution.

Survey for papillomatous digital dermatitis in Australian dairy cattle

Objective To determine whether Treponema-associated papillomatous digital dermatitis (PDD) occurs in Australian dairy cattle. Design Mail-out questionnaire and histological and bacteriological examination of biopsy tissue from suspect PDD lesions. Procedure The questionnaire was mailed to 375 veterinarians to evaluate their knowledge of PDD, determine if they had observed the disease in Australian dairy cattle, and to request biopsy material from suspicious cases. Biopsies were examined for histological and bacteriological evidence of PDD, including for the presence of spirochaetes. Results Eighty-eight replies to the questionnaire were received (23.5%). Of 52 respondents who were aware of PDD as a possible cause of lameness, 26 reported observing the condition in Australian cattle. Of 32 respondents who were unaware of the condition, 6 reported observing lesions that might have been PDD. The majority of reports of PDD-like lesions came from the southern Australian states, the condition occurring during periods of high rainfall and proving responsive to topical or parenteral application of antimicrobials. Biopsies from five erosive lesions showed histological similarity to PDD whereas biopsies from five proliferative lesions were consistent with chronic inflammation, fibroma or cutaneous papilloma. The presence of spirochaetes was not demonstrated in any of the lesions by histological or bacteriological methods. Conclusion Anecdotal reports and analysis of biopsy material confirm that a condition similar to PDD does occur sporadically in dairy cattle in southern Australia. However, this condition has so far not been shown to be associated with the presence of spirochaetes in the lesions.

Identification and cloning of the gene encoding BmpC: an outer-membrane lipoprotein associated with Brachyspira pilosicoli membrane vesicles

The intestinal spirochaete Brachyspira pilosicoli causes colitis in a wide variety of host species. Little is known about the structure or protein constituents of the B. pilosicoli outer membrane (OM). To identify surface-exposed proteins in this species, membrane vesicles were isolated from B. pilosicoli strain 95-1000 cells by osmotic lysis in dH(2)O followed by isopycnic centrifugation in sucrose density gradients. The membrane vesicles were separated into a high-density fraction (HDMV; p = 1.18 g CM-3) and a low-density fraction (LDMV; rho=1.12 g cm(-3)). Both fractions were free of flagella and soluble protein contamination. LDMV contained predominantly OM markers (lipo-oligosaccharide and a 29 kDa B. pilosicoli OM protein) and was used as a source of antigens to produce mAbs. Five B. pilosicoli-specific mAbs reacting with proteins with molecular masses of 23, 24, 35, 61 and 79 kDa were characterized. The 23 kDa protein was only partially soluble in Triton X-114, whereas the 24 and 35 kDa proteins were enriched in the detergent phase, implying that they were integral membrane proteins or lipoproteins. All three proteins were localized to the B. pilosicoli OM by immunogold labelling using specific mAbs. The gene encoding the abundant, surface-exposed 23 kDa protein was identified by screening a B. pilosicoli 95-1000 genome library with the mAb and was expressed in Escherichia coli. Sequence analysis showed that it encoded a unique lipoprotein, designated BmpC. Recombinant BmpC partitioned predominantly in the OM fraction of E. coli strain SOLR. The mAb to BmpC was used to screen a collection of 13 genetically heterogeneous strains of B. pilosicoli isolated from five different host species. Interestingly, only strain 95-1000 was reactive with the mAb, indicating that either the surface-exposed epitope on BmpC is variable between strains or that the protein is restricted in its distribution within B. pilosicoli.

Localization of immunoreactivity for deleted in colorectal cancer (DCC), the receptor for the guidance factor netrin-1, in ventral tier dopamine projection pathways in adult rodents

DCC (deleted in colorectal cancer)-the receptor of the netrin-1 neuronal guidance factor-is expressed and is active in the central nervous system (CNS) during development, but is down-regulated during maturation. The substantia nigra contains the highest level of netrin-1 mRNA in the adult rodent brain, and corresponding mRNA for DCC has also been detected in this region but has not been localized to any particular neuron type. In this study, an antibody raised against DCC was used to determine if the protein was expressed by adult dopamine neurons, and identify their distribution and projections. Significant DCC-immunoreactivity was detected in midbrain, where it was localized to ventrally displaced A9 dopamine neurons in the substantia nigra, and ventromedial A10 dopamine neurons predominantly situated in and around the interfascicular nucleus. Strong immunoreactivity was not detected in dopamine neurons found elsewhere, or in non-dopamine-containing neurons in the midbrain. Terminal fields selectively labeled with DCC antibody corresponded to known nigrostriatal projections to the dorsolateral striatal patches and dorsomedial shell of the accumbens, and were also detected in prefrontal cortex, septum, lateral habenular and ventral pallidum. The unique distribution of DCC-immunoreactivity in adult ventral midbrain dopamine neurons suggests that netrin-1/DCC signaling could function in plasticity and remodeling previously identified in dopamine projection pathways. In particular, a recent report that DCC is regulated through the ubiquitin-proteosome system via Siah/Sina proteins, is consistent with a potential involvement in genetic and sporadic forms of Parkinson's disease. (c) 2005 IBRO. Published by Elsevier Ltd. All rights reserved.

Molecular mechanisms for the variation of mitochondrial gene content and gene arrangement among chigger mites of the genus Leptotrombidium (Acari : Acariformes)

The gene content of a mitochondrial (mt) genome, i.e., 37 genes and a large noncoding region (LNR), is usually conserved in Metazoa. The arrangement of these genes and the LNR is generally conserved at low taxonomic levels but varies substantially at high levels. We report here a variation in mt gene content and gene arrangement among chigger mites of the genus Leptotrombidium. We found previously that the mt genome of Leptotrombidium pallidum has an extra gene for large-subunit rRNA (rrnL), a pseudo-gene for small-subunit rRNA (PrrnS), and three extra LNRs, additional to the 37 genes and an LNR typical of Metazoa. Further, the arrangement of mt genes of L. pallidum differs drastically from that of the hypothetical ancestor of the arthropods. To find to what extent the novel gene content and gene arrangement occurred in Leptotrombidium, we sequenced the entire or partial mt genomes of three other species, L. akamushi, L. deliense, and L. fletcheri. These three species share the arrangement of all genes with L. pallidum, except trnQ (for tRNA-glutamine). Unlike L. pallidum, however, these three species do not have extra rrnL or PrrnS and have only one extra LNR. By comparison between Leptotrombidium species and the ancestor of the arthropods, we propose that (1) the type of mt genome present in L. pallidum evolved from the type present in the other three Leptotrombidium species, and (2) three molecular mechanisms were involved in the evolution of mt gene content and gene arrangement in Leptotrombidium species.