296 research outputs found
Migratory departures of waders From north-western Australia:Behaviour, timing and possible migration routes
Migratory activity of waders departing from north-western Australia in March-April 1991 was recorded by field observations and radar tracking. Field observations showed that the species concerned were mainly Bar-tailed Godwit Limosa lapponica, Grey Plover Pluvialis squatarola and Great Knot Calidris tenuirostris. Peak migration took place in the second week of April. Most flocks departed in the late afternoon, never at high tide. A strong correlation was found between the tidal cycle and the timing of departures. The majority of the flocks flew towards NNW. Given that the next stopover site of especially the larger sized waders is in east and south China (Barter & Wang 1990) this observed departure direction is more westerly than a course along the great circle route (0-degree). Wind patterns along two possible northward routes (a great circle and an island hopping route along the island-arc of South-east Asia) are analysed. In view of recoveries of waders ringed in Australia, especially the smaller waders (Mongolian Plover Charadrius mongolus, Large Sandplover Charadrius leschenaultii, Red-necked Stint Calidris ruficollis, Curlew Sandpiper Calidris ferruginea, Broad-billed Sandpiper Limicola falcinellus, Terek Sandpiper Xenus cinereus) may migrate via the island hopping route, while the larger ones (Grey Plover, Great Knot, Red Knot Calidris canutus, Bar-tailed Godwit, Whimbrel Numenius phaeopus and Eastern Curlew Numenius madagascariensis) take a direct, great circle flight to China. Considerable tail wind assistance can be gained during the northward trip, more so along the island arc than along the great circle. Flight range estimates indicate that the smaller waders cannot fly the 4500-5500 km nonstop to east and south China, while the larger species can, on the condition that they experience tail wind assistance.</p
DNA-stable isotope probing (DNA-SIP) identifies marine sponge-associated bacteria actively utilizing dissolved organic matter (DOM)
DNA-stable isotope probing (DNA-SIP) identifies marine sponge-associated bacteria actively utilizing dissolved organic matter (DOM)
Sponges possess exceptionally diverse associated microbial communities and play a major role in (re)cycling of dissolved organic matter (DOM) in marine ecosystems. Linking sponge‐associated community structure with DOM utilization is essential to understand host–microbe interactions in the uptake, processing, and exchange of resources. We coupled, for the first time, DNA‐stable isotope probing (DNA‐SIP) with 16S rRNA amplicon sequencing in a sponge holobiont to identify which symbiotic bacterial taxa are metabolically active in DOM uptake. Parallel incubation experiments with the sponge Plakortis angulospiculatus were amended with equimolar quantities of unlabelled ((12)C) and labelled ((13)C) DOM. Seven bacterial amplicon sequence variants (ASVs), belonging to the phyla PAUC34f, Proteobacteria, Poribacteria, Nitrospirae, and Chloroflexi, were identified as the first active consumers of DOM. Our results support the predictions that PAUC34f, Poribacteria, and Chloroflexi are capable of organic matter degradation through heterotrophic carbon metabolism, while Nitrospirae may have a potential mixotrophic metabolism. We present a new analytical application of DNA‐SIP to detect substrate incorporation into a marine holobiont with a complex associated bacterial community and provide new experimental evidence that links the identity of diverse sponge‐associated bacteria to the consumption of DOM
Effecten van experimentele bekalking en bemesting op de ondergroei van enkele eiken- en dennenbossen op arme zandgrond in Nederland : beschrijving van de uitgangssituatie
Reef sponges facilitate the transfer of coral-derived organic matter to their associated fauna via the sponge loop
The high biodiversity of coral reefs results in complex trophic webs where energy and nutrients are transferred between species through a multitude of pathways. Here, we hypothesize that reef sponges convert the dissolved organic matter released by benthic primary producers (e.g. corals) into particulate detritus that is transferred to sponge-associated detritivores via the sponge loop pathway. To test this hypothesis, we conducted stable isotope (13C and15N) tracer experiments to investigate the uptake and transfer of coral-derived organic matter from the sponges Mycale fistulifera and Negombata magnifica to 2 types of detritivores commonly associated with sponges: ophiuroids (Ophiothrix savignyi and Ophiocoma scolopendrina) and polychaetes (Polydorella smurovi). Findings revealed that the organic matter naturally released by the corals was indeed readily assimilated by both sponges and rapidly released again as sponge detritus. This detritus was subsequently consumed by the detritivores, demonstrating transfer of coral-derived organic matter from sponges to their associated fauna and confirming all steps of the sponge loop. Thus, sponges provide a trophic link between corals and higher trophic levels, thereby acting as key players within reef food webs
A characterization of the molecular phenotype and inflammatory response of schizophrenia patient-derived microglia-like cells
Different lines of evidence support a causal role for microglia in the pathogenesis of schizophrenia. However, how schizophrenia patient-derived microglia are affected at the phenotypic and functional level is still largely unknown. We used a recently described model to induce patient-derived microglia-like cells and used this to analyze changes in the molecular phenotype and function of myeloid cells in schizophrenia. We isolated monocytes from twenty recent-onset schizophrenia patients and twenty non-psychiatric controls. We cultured the cells towards an induced microglia-like phenotype (iMG), analyzed the phenotype of the cells by RNA sequencing and mass cytometry, and their response to LPS. Mass cytometry showed a high heterogeneity of iMG in cells derived from patients as well as controls. The prevalence of two iMG clusters was significantly higher in schizophrenia patients (adjusted p-value <0.001). These subsets are characterized by expression of ApoE, Ccr2, CD18, CD44, and CD95, as well as IRF8, P2Y(12), Cx3cr1 and HLA-DR. In addition, we found that patient derived iMG show an enhanced response to LPS, with increased secretion of TNF-alpha. Further studies are needed to replicate these findings, to determine whether similar subclusters are present in schizophrenia patients in vivo, and to address how these subclusters are related to the increased response to LPS, as well as other microglial functions
Field Report: Anna Plains and Roebuck Bay Benthic Invertebrate Mapping 2016
This project has been funded by the Department of Parks and Wildlife partnership with BHP Billiton “Eighty Mile Beach and Walyarta Conservation Program”, with in-kind support from NIOZ and Wetland Research & Management This report was produced at the Broome Bird Observatory in late October 2016. Abstract 1. This is a report on repeat surveys on the state of the benthic invertebrates at two internationally important areas of intertidal mudflats in northwest Australia (Roebuck Bay and Eighty Mile Beach) during October 2016. In the period 6-19 October 2016, we mapped the invertebrate macrobenthic animals (those retained by a 1 mm sieve) at the main intertidal sites of West Kimberley, WA: Eighty Mile Beach and Roebuck Bay. We revisited almost the entire intertidal area along Eighty Mile Beach that was ‘benthically’ mapped in October 1999. The benthic animals of the northern mudflats of Roebuck Bay had been mapped in 1997, 2000, 2002, and 2006; we revisited as many as possible of these previously established sampling stations along the northern shore. 2. Our team comprised close to 100 participants with greatly varying levels of experience, though similarly high motivation and enthusiasm. At Eighty Mile Beach we visited 816 sampling stations laid out in a grid of 200 m intersections over 7 separate areas along ca. 75 km of beach (from 10 km north of the Anna Plains Station beach access to 65 km south). In the northern part of Roebuck Bay, we visited 534 sampling stations also laid out in a grid with 200 m intersections (but with distance of 400 m in the southeast). We made notes on the surface features on the mud, including the presence or absence of seagrass and various macrofauna. In the course of digging up, sieving, and sorting the mud samples from all stations, we identified and measured 32,500 individual invertebrates. We tried to identify all animals groups up to the level of species if possible, all on the basis of morphological differences. These species were often given field names, as time and means (literature or access to internet) did not allow us to always attach a proper scientific name. In addition, it is very likely that some of the species are still undescribed. Animals were preserved on ethanol for a more thorough scientific identification at a later date. 3. This time we surveyed two very distinct sections of the West Kimberley coast. Roebuck Bay represents a true embayment that is semi-enclosed by mangroves along the eastern, and some of the western shores, and by cliff and pindan woodlands in the north. Eighty Mile Beach stretches over 200 km along the open Indian Ocean facing northwest. In this environment, the intertidal mud- and sandflat area stretches from 1-5 km wide from shore to sea and is enclosed by sand dunes and a few mangroves. Despite the two systems being very important as nonbreeding areas for the same species of long-distance migrant shorebirds, their geomorphology and ecology are very distinct. 4. At both areas the biodiversity of benthic animals was very high compared with other intertidal soft sediment areas across in the world. In Roebuck Bay, 368 species were found, and at Eighty Mile Beach 156 species, providing a total of 433 species/taxa. The most diverse group were the Polychaeta with 167 species, followed by Crustacea (74), Bivalvia (59), Gastropoda (59), and Echinodermata (35). All other groups total less than 12 species. 5. The two areas have 92 species in common, which in the case of Eighty Mile Beach means that 60% of the species also occur in Roebuck Bay. Major groups not found at Eighty Mile Beach were Asteroidea, Brachiopoda, Hirudinea, Oligochaeta, Platyhelminthes, Polyplacophora, and Pycnogonida. Most of these groups were also rare in Roebuck Bay, but the absence of Brachiopoda (lamp-shells) and Pycnogonida (seaspiders) at Eighty Mile Beach came as a surprise. Some species, including two species of Spionidae (Polychaeta) common at Eighty Mile Beach were either absent or extremely rare at Roebuck Bay. Furthermore, a small seacucumber with dark coloured spots all over its body, another larger seacucumber Paracaudina chilensis, two bivalve species of the genus Tellina, and two species of anemones were not found in Roebuck Bay. Yet, Roebuck Bay had many more species (277) not found at Eighty Mile Beach, the most common of these was the relatively large bivalve Tellina piratica, followed by the smooth tusk shell (Laevidentalium lubricatum), and the polychaete family Sternaspidae. 6. The large difference in biodiversity between Roebuck Bay and Eighty Mile Beach may be caused by different factors. Roebuck Bay has a greater variety of sedimentary habitats than Eighty Mile Beach. Eighty Mile Beach is completely exposed to the waves of Indian Ocean, while Roebuck Bay is protected by the peninsula on which Broome is situated. Therefore, notorious ‘ecosystem engineers’ such as the seagrasses occur quite extensively on the intertidal area of Roebuck Bay, but are not found at Eighty Mile Beach. These seagrass mats of Halodula uninervis and Halophila ovalis form special habitat for e.g. the little snail Smaragdia souverbiana. The influence of Broome city by episodic sewage and fertilizer releases, of which blooms of the cyanobacteria Lyngbya are an indication, can may well have a negative influence; opportunistic widespread species other than Lyngbya may of course benefit from the additional nutrient inputs. 7. Local communities and the land-owners actively participated in both expeditions. Several DPAW ranger groups (Yawuru, Karajarri and Nyangumarta) joined the sampling and also aided in the identification of species. Angela Rossen (WAMSI) spearheaded a biodiversity project that involved pupils from Cable Beach Primary School. We believe that we have raised wide awareness and generated considerable enthusiasm for the ecology of a unique contribution of northwest Australia to the world. 8. Based on their outstanding universal values, we recommend that the WA government consider an application of the joint marine reserves of Eighty Mile Beach and Roebuck Bay for World Heritage Status, thus joining China and South Korea in acknowledging and protecting this shared heritage
Dietary Folate and APC Mutations in Sporadic Colorectal Cancer.
Folate deficiency has been associated with colorectal cancer risk and may be involved in colorectal carcinogenesis through increased chromosome instability, gene mutations, and aberrant DNA methylation. Within the Netherlands Cohort Study on diet and cancer, we investigated the associations between dietary folate intake and colorectal cancer risk with (APC+) and without (APC-) truncating APC mutations, accounting for hMLH1 expression and K-ras mutations. In total, 528 cases and 4200 subcohort members were available for data analyses of the study cohort (n = 120,852) from a follow-up period between 2.3 and 7.3 y after baseline. Adjusted gender-specific incidence rate ratios (RR) over tertiles of folate intake were calculated in case-cohort analyses for colon and rectal cancer. Although relatively high folate intake was not associated with overall colorectal cancer risk, it reduced the risk of APC- colon tumors in men (RR 0.58, 95% CI 0.32-1.05, P trend = 0.06 for the highest vs. lowest tertile of folate intake). In contrast, it was positively associated with APC+ colon tumors in men (highest vs. lowest tertile: RR 2.77, 95% CI 1.29-5.95, Ptrend = 0.008) and was even stronger when the lack of hMLH1 expression and K-ras mutations were excluded (RR 3.99, 95% CI 1.43-11.14, Ptrend = 0.007). Such positive associations were not observed among women; nor was folate intake associated with rectal cancer when APC mutation status was taken into account. Relatively high folate consumption reduced the risk of APC- colon tumors, but folate intake was positively associated with APC+ colon tumors among men. These opposite results may indicate that folate enhances colorectal carcinogenesis through a distinct APC mutated pathway. © 2006 American Society for Nutrition
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