Monitoring the fluvial palynomorph load in a lowland temperate catchment and its relationship to suspended sediment and discharge

Despite it being a component of the seston we know very little about fluvial (waterborne) pollen and spore (palynomorph) transport. This paper presents the results of a monitoring programme conducted over two years and at a catchment scale in South West England. A hierarchical monitoring network was established with flood peak samples taken at 9 sub-catchments, intra-hydrograph samples taken in two sub-catchments and time-integrated sampling undertaken at one location. In addition sampling was undertaken of probable palynomorph sources such as channel bed and bank sediments, and the airborne pollen flux was monitored using modified Tauber traps. The results support previous research in illustrating how the vast majority of fluvial pollen and spores are transported during floods (91%) and that the main control on waterborne palynomorph assemblages is the catchment vegetation and its spatial distribution but with a long-distance (extra-catchment) component. However, strong seasonal effects are also shown, and the importance of distinctive sources such as the riparian input, bed re-suspension and overland flow into drains and tributaries is revealed. Fine sediment in river pools appears to act as a selective store of damaged cereal type pollen grains derived from arable fields. Although pollen does form part of composite particles the data presented here suggest that the majority of the pollen is transported as single grains. Fluvial palynomorph loading is strongly dependant upon discharge and so concentrations in laminated or varved sediments could be regarded as a proxy for flood magnitude. Handling editor: J. Saros     

Control techniques for Culicoides biting midges and their application in the U.K. and northwestern Palaearctic

The recent emergence of bluetongue virus (Reoviridae: Orbivirus) (BTV) in northern Europe, for the first time in recorded history, has led to an urgent need for methods to control the disease caused by this virus and the midges that spread it. This paper reviews various methods of vector control that have been employed elsewhere and assesses their likely efficacy for controlling vectors of BTV in northern Europe. Methods of controlling Culicoides spp. (Diptera: Ceratopogonidae) have included: (a) application of insecticides and pathogens to habitats where larvae develop; (b) environmental interventions to remove larval breeding sites; (c) controlling adult midges by treating either resting sites, such as animal housing, or host animals with insecticides; (d) housing livestock in screened buildings, and (e) using repellents or host kairomones to lure and kill adult midges. The major vectors of BTV in northern Europe are species from the Culicoides obsoletus (Meigen) and Culicoides pulicaris (L.) groups, for which there are scant data on breeding habits, resting behaviour and host-oriented responses. Consequently, there is little information on which to base a rational strategy for controlling midges or for predicting the likely impact of interventions. However, data extrapolated from the results of vector control operations conducted elsewhere, combined with some assessment of how acceptable or not different methods may be within northern Europe, indicate that the treatment of livestock and animal housing with pyrethroids, the use of midge-proofed stabling for viraemic or high-value animals and the promotion of good farm practice to at least partially eliminate local breeding sites are the best options currently available. Research to assess and improve the efficacy of these methods is required and, in the longer term, efforts should be made to develop better bait systems for monitoring and, possibly, controlling midges. All these studies will need better methods of analysing the ecology and behaviour of midges in the field than are currently in use. The paucity of control options and basic knowledge serve to warn us that we must be better prepared for the possible emergence of other midge-borne diseases, particularly African horse sickness.     

Production of human platelet lysate by use of ultrasound for ex vivo expansion of human bone marrow–derived mesenchymal stromal cells

Background aimsA medium supplemented with fetal bovine serum (FBS) is of common use for the expansion of human mesenchymal stromal cells (MSCs). However, its use is discouraged by regulatory authorities because of the risk of zoonoses and immune reactions. Human platelet lysate (PL) obtained by freezing/thawing disruption of platelets has been proposed as a possible substitute of FBS. The process is time-consuming and not well standardized. A new method for obtaining PL that is based on the use of ultrasound is proposed.MethodsPlatelet sonication was performed by submerging platelet-containing plastic bags in an ultrasonic bath. To evaluate platelet lysis we measured platelet-derived growth factor-AB release. PL efficiency was tested by expanding bone marrow (BM)-MSCs, measuring population doubling time, differentiation capacity and immunogenic properties. Safety was evaluated by karyotyping expanded cells.ResultsAfter 30 minutes of sonication, 74% of platelet derived growth factor-AB was released. PL enhanced BM-MSC proliferation rate compared with FBS. The mean cumulative population doubling (cPD) of cells growth in PL at 10%, 7.5% and 5% was better compared with cPD obtained with 10% FBS. PD time (hours) of MSCs with PL obtained by sonication was shorter than for cPD with PL obtained by freezing/thawing (18.9 versus 17.4, P < 0.01). BM mononucleated cells expressed MSC markers and were able to differentiate into adipogenic, osteogenic and chondrogenic lineages. When BM-MSCs and T cells were co-cultured in close contact, immunosuppressive activity of BM-MSCs was maintained. Cell karyotype showed no genetic alterations.ConclusionsThe proposed method for the production of PL by sonication could be a safe, efficient and fast substitute of FBS, without the potential risks of FBS.     

Tyrosine phosphorylation of phospholipase C-II in vitro by the epidermal growth factor receptor

In a number of cell lines, epidermal growth factor (EGF) rapidly stimulates the breakdown of inositol phospholipids. Phosphatidylinositol-specific phospholipase C (PLC), therefore, plays an important role in this biological response to EGF, but the mechanism by which EGF-receptor complexes modulate the activation of PLC is not understood. We have previously suggested that tyrosine phosphorylation of PLC or an unknown PLC-associated protein by the EGF receptor is involved in the activation process (Wahl, M. I., Daniel, T. O., and Carpenter, G. (1988) Science 241, 968-970) and have recently shown by immunoprecipitation that the addition of EGF to 32P-labeled cells increases tyrosine and serine phosphorylation of PLC-II (Wahl, M. I., Nishibe, S., Suh, P.-G., Rhee, S. G., and Carpenter, G. (1989) Proc. Natl. Acad. Sci. U.S.A. 86, 1568-1572). In this communication we demonstrate that PLC-II (Mr = 145,000) purified from bovine brain can be phosphorylated in vitro in an EGF-dependent manner by the tyrosine kinase activity of the purified EGF receptor. While PLC-II is an efficient phosphorylation substrate for the purified EGF receptor, PLC-I is a poor substrate and PLC-III is not phosphorylated to any detectable extent. Though all three PLC isozymes possess typical tyrosine phosphorylation sequences, the EGF receptor is surprisingly selective in vitro for the phosphorylation of PLC-II. High performance liquid chromatography comparison of tryptic phosphotyrosyl peptides from PLC-II phosphorylated in vivo and in vitro indicated a similar pattern of multiple tyrosine phosphorylation sites. These findings show that the EGF receptor can directly phosphorylate PLC-II in an efficient and selective manner.     

A new method for demonstrating argyrophil cells of the pancreas and intestines

A new method for demonstrating argyrophil cells of the pancreas and intestinal tract using a combined silver and reducing solution in sections of formaldehyde fixed tissue is described. Impregnating sections in a 60 C water bath, the procedure takes about 25 min. A microwave version that takes about 5 min is also given. Results are similar to those obtained with the Grimelius method for argyrophil cells.     

Diurnal space use and nocturnal roost‐site selection by male Cerulean Warblers during the breeding season

Detailed information about space use during the breeding season is limited for most Nearctic‐Neotropical migratory species of songbirds because of their small size and often cryptic behaviors. We monitored male Cerulean Warblers (Setophaga cerulea), a species of conservation concern, using radio‐telemetry during the 2006–2008 breeding seasons in northern Alabama to better understand their space use and habitat selection. We estimated diurnal home range and core areas using information theoretic criteria, located nocturnal roost sites, and related day and evening locations to surrounding landscape habitat, including features representative of canopy disturbances. Mean home range size was 6.7 ha (N = 10), and home ranges included an average of at least 2 core areas encompassing 0.7 ha. We located 53 nocturnal roost sites that were an average 159.0 m from the center of the nearest core area. More than one‐third (36.6%) of roost sites were located outside the diurnal home ranges of male Cerulean Warblers; only 13.6% were located in core areas. Males in our study moved much farther than reported in previous studies, with some singing in areas > 300 m from previously used song perches, a behavior suggesting pursuit of extra‐pair copulations. Cerulean Warblers in our study preferentially selected a heavily forested landscape composed of mesic, floodplain bottomlands with little man‐made disturbance. Within their home ranges, diurnal locations of males in core areas were located significantly closer to a creek than locations outside of core areas. Our results suggest that male Cerulean Warblers require much larger areas than previously reported and underscore the importance of a predominately forested landscape in their habitat selection process. Although edge habitats appeared to influence space use by male Cerulean Warblers in our study, the extent to which this is an essential requirement is unclear. Our results and those of previous studies suggest that specific habitat requirements of this species can vary at the local scale throughout its breeding range.     

Molecular Phylogeography of Oncomelania Lindoensis (Gastropoda: Pomatiopsidae), the Intermediate Host of Schistosoma Japonicum in Sulawesi

Oncomelania lindoensis from Lake Lindu, Sulawesi, was characterizedfor genetic variation at 21 allozyme loci and compared withO. hupensis (China) and O. quadrasi (Philippines). Geneticdistances and interpopulation patterns of allele-sharing pointto a closer relationship between Sulawesi and the Philippines(Nei's unbiased genetic distances (D) averaged 0.50) than betweenSulawesi and China (D= 0.79). These data, coupled with a considerationof the geographic distribution of the genus, support the hypothesisthat the Sulawesi Oncomelaniaoriginated by avian-facilitated colonizationfrom the Philippines about two million years ago. Oncomelania from Sulawesi were originally described as subspecificallydistinct: Oncomelania hupensis lindoensis. However, the allopatricdistribution, unique alleles at five loci, and significant geneticdistances from congeners in Mindanao and elsewhere in the Philippinessuggest that this taxon should be distinguished as a full specieswithin the Oncomelania hupensis species group, namely: O. lindoensisDavis & Carney 1973. Comparison with published data on variationwithin quadrasi and in three Chinese subspecies of hupensisshowed that D values increase with taxonomic level in this speciesgroup. D averaged 0.15 (0–0.26) within Chinese subspeciesand 0.04 (0–0.13) within the Philippines, but was 0.30(0.20–0.45) between Chinese subspecies, and 0.48–0.80between the three species (hupensis, quadrasi and lindoensis).The genotypic cluster species concept and these multilocus geneticdistances can be used to help define species and subspeciesin these medically important snails. (Received 14 May 1997; accepted 20 April 1998)