Sub-fossils of cladocerans in the surface sediment of 135 lakes as proxies for community structure of zooplankton,fish abundance and lake temperature

To elucidate the possibilities of using zooplankton remains in the surface sediment to describe present-days community structure and population dynamics of zooplankton, fish abundance and temperature, we compared contemporary data sampled in the pelagial during summer with the sediment record from the upper 1 cm of the sediment in 135 lakes covering a latitude gradient from Greenland in the north to New Zealand in the south. The abundance of three genera Bosmina, Daphnia and Ceriodaphnia of the total pool of ephippia was significantly related to the total abundance of the same taxa in the pelagic zone. However, in most lakes the abundance of Ceriodaphnia was higher in the sediment than in the water, which may be attributed to the overall preference by this genus for the littoral habitat. Using contemporary data from 27 Danish lakes sampled fortnightly during summer for 10 years, we found substantial inter-annual variations in the abundance of Daphnia spp., Ceriodaphnia spp., B. longirostris and B. coregoni. Yet, the sediment record mimicked the medium level well for most of the lakes, which suggests that the sediment record provides an integrated picture of the pelagic cladoceran community, which otherwise can be obtained only by long-term frequent contemporary sampling for several years. The contribution of Daphnia to the sum of Daphnia and Bosmina ephippia was negatively correlated with the abundance of fish expressed as catch per night in multi-mesh sized gill nets (CPUE). Yet, region-specific differences occurred, which partly could be eliminated by including nutrient state expressed as total phosphorus (TP) in a multiple regression. The average ratio of ephippia to the sum of ephippia and carapaces of Bosmina varied 40-fold between the sampling regions and was significantly negatively related to summer mean air temperature, and for Danish lakes also, albeit weakly, to fish CPUE but not to chlorophyll a. Apparently, temperature is the most important factor determining the ratio of parthenogenetic to ephippia producing specimens of Bosmina. We conclude that the sediment record of cladocerans is a useful indicator of community structure of pelagic cladocerans and the abundance of fish and temperature.     

Mobility of Stichodactyla Gigantea Sea Anemones and Implications for Resident False Clown Anemonefish, Amphiprion Ocellaris

For reef fishes that do not move between habitat patches following settlement, habitat selection is expected during settlement. Although false clown anemonefish, Amphiprion ocellaris, are sedentary following settlement, they are not especially discriminating during settlement, and are commonly found occupying anemones at which no apparent nest site exists. In this study I report on mobility of Stichodactyla gigantea sea anemones, including anemones with resident false clowns. I argue that anemone mobility can help explain why settling false clowns are not more discriminating: although the per annum probability of an anemone moving is low, the probability of that anemone moving over the course of a resident's life is considerably higher. Therefore, an anemone's current microhabitat may not be a good predictor of its microhabitat and suitability as a host in the future.     

The influence of carrageenan on molecular mobility in low moisture amorphous sugars

The influence of less than 1% of κ-carrageenan on the mobility of glucose syrup was studied in the context of the glass–rubber transition using proton NMR relaxometry. Glass-transition temperatures, (T_g) were measured by differential scanning calorimetry (DSC) on glucose syrup samples containing 0 or 0.9% κ-carrageenan, between 0 and 1.4% KCl, and at water contents from 3.5 to 16% (wwb). Potassium chloride was added to vary the extent of gelation of the carrageenan in order to assess the effect of the biopolymer network on molecular mobility.

Contrary to the reported increase of the rheologically determined glass-transition temperature, in the presence of gelling agents, the addition of 0.9% κ-carrageenan to glucose syrup with and without KCl, had no effect on the DSC measured T_g. In addition, there was no effect on molecular mobility in the glassy region. The presence of carrageenan only significantly affected the mobile part of the NMR free induction decay at relatively high temperatures.     

Molecular Mechanism of Insulin-Induced Degradation of Insulin Receptor Substrate 1

Insulin receptor substrate 1 (IRS-1) plays an important role in the insulin signaling cascade. In vitro and in vivo studies from many investigators have suggested that lowering of IRS-1 cellular levels may be a mechanism of disordered insulin action (so-called insulin resistance). We previously reported that the protein levels of IRS-1 were selectively regulated by a proteasome degradation pathway in CHO/IR/IRS-1 cells and 3T3-L1 adipocytes during prolonged insulin exposure, whereas IRS-2 was unaffected. We have now studied the signaling events that are involved in activation of the IRS-1 proteasome degradation pathway. Additionally, we have addressed structural elements in IRS-1 versus IRS-2 that are required for its specific proteasome degradation. Using ts20 cells, which express a temperature-sensitive mutant of ubiquitin-activating enzyme E1, ubiquitination of IRS-1 was shown to be a prerequisite for insulin-induced IRS-1 proteasome degradation. Using IRS-1/IRS-2 chimeric proteins, the N-terminal region of IRS-1 including the PH and PTB domains was identified as essential for targeting IRS-1 to the ubiquitin-proteasome degradation pathway. Activation of phosphatidylinositol 3-kinase is necessary but not sufficient for activating and sustaining the IRS-1 ubiquitin-proteasome degradation pathway. In contrast, activation of mTOR is not required for IRS-1 degradation in CHO/IR cells. Thus, our data provide insight into the molecular mechanism of insulin-induced activation of the IRS-1 ubiquitin-proteasome degradation pathway.     

Conduction pathways in microtubules, biological quantum computation, and consciousness.

Technological computation is entering the quantum realm, focusing attention on biomolecular information processing systems such as proteins, as presaged by the work of Michael Conrad. Protein conformational dynamics and pharmacological evidence suggest that protein conformational states-fundamental information units ('bits') in biological systems-are governed by quantum events, and are thus perhaps akin to quantum bits ('qubits') as utilized in quantum computation. 'Real time' dynamic activities within cells are regulated by the cell cytoskeleton, particularly microtubules (MTs) which are cylindrical lattice polymers of the protein tubulin. Recent evidence shows signaling, communication and conductivity in MTs, and theoretical models have predicted both classical and quantum information processing in MTs. In this paper we show conduction pathways for electron mobility and possible quantum tunneling and superconductivity among aromatic amino acids in tubulins. The pathways within tubulin match helical patterns in the microtubule lattice structure, which lend themselves to topological quantum effects resistant to decoherence. The Penrose-Hameroff 'Orch OR' model of consciousness is reviewed as an example of the possible utility of quantum computation in MTs.     

Familial idiopathic basal ganglia calcification (Fahr's disease) without neurological, cognitive and psychiatric symptoms is not linked to the IBGC1 locus on chromosome 14q

Idiopathic basal ganglia calcification (IBGC) is characterised by radiological, neurological, cognitive and psychiatric abnormalities. The associations between these abnormal phenotypes and abnormal genes remain unclear despite the recent mapping to chromosome 14q of a susceptibility locus for IBGC ( IBGC1). We identified two siblings, from a large multigenerational pedigree, who had both been diagnosed with radiological IBGC, dementia, bipolar affective disorder and Parkinsonism. We assessed (1) other family members to determine whether these four phenotypes were co-segregating as symptoms of IBGC, and (2) possible IBGC linkage to the IBGC1 locus on chromosome 14q or to any known or potential dementia genes. Nine second-generation and 21 third-generation members received radiological, neurological, neuropsychological and psychiatric assessments. We genotyped all family members for microsatellite markers at the IBGC1 locus and polymorphisms of the ApoE, VLDL, alpha1-ACT, BChE-K, APP, PS1, PS2 and tau genes and tested these for linkage to IBGC, dementia and bipolar disorder. Of the ten family members with radiological intracranial calcification, all except the two index cases were normal. There was no significant association between IBGC status and severe cognitive impairment or dementia ( P=0.335) or bipolar affective disorder or Parkinsonism ( P=1.0). Linkage to the IBGC1 locus was excluded. Of the eight dementia gene markers tested, the only positive LOD score was for the ApoE epsilon4 polymorphism and dementia/severe cognitive impairment. We have identified a form of IBGC in which calcification is inherited independently of neurological, cognitive and psychiatric symptoms. This may represent a second locus for this disorder.     

‘Heaven’ for serpents? A mark–recapture study of tiger snakes (Notechis scutatus) on Carnac Island,Western Australia

Abstract Animals resident on small islands provide excellent opportunities to carry out detailed mark–recapture studies. Populations are closed and ecosystems are often simpler than those of mainland sites. These factors enable the study of cryptic species that have otherwise been neglected. Snakes are notable for their secretive nature and, as a result, few natural populations have been accurately described through long‐term mark–recapture monitoring. A population of tiger snakes (Notechis scutatus) was studied on Carnac Island, a small limestone island (16 ha) off the coast of Western Australia. Population estimates show that snake density is very high, with more than 20 adult snakes per ha. This equates to a biomass of more than 100 kg of a top predator concentrated in a very small area. Such a high predator density can be explained because adult snakes feed mainly on chicks of nesting birds that breed in large colonies on Carnac but forage elsewhere. Substantial annual growth rates in body size in most individuals suggest that food availability is high on Carnac. Growth rates decreased more sharply in adult females than in males, whereas annual changes in body mass were similar in both sexes, probably because of the high energetic costs of reproduction experienced by females. Surprisingly, the sex ratio was highly biased, with males largely outnumbering females.