Variations in net litter nutrient input associated with tree species influence on soil nutrient contents in a subtropical evergreen broad-leaved forest

The influence of tree species on soils has received much attention,but we know little about either the pattern and underlying mechanisms of net nutrient and carbon inputs under canopy for various tree species or the effects of net nutrient input on soil nutrient contents.To address these issues,we selected three tree species with distinct leaf sizes and arranged litter traps around the target individuals to test what affected net nutrient and carbon inputs under canopy of target individuals,and how net nutrient inputs influenced soil nutrient contents.The results showed that net litter manganese(Mn)and lignin inputs were significantly different among these tree species,as well as soil exchangeable potassium(K),available iron(Fe)and available Mn.The results also revealed that the species with the smallest sized leaves may stimulate more net Mn and lignin inputs than the species with the largest sized leaves.At the same time,net nutrient inputs correlated with soil available Fe,while the ratio of lignin to nitrogen of net litter correlated with total phosphorus contents.These results demonstrated that litter production may be the main factor deciding net nutrient and carbon inputs under different tree species’canopy,which significantly differentiated soil iron’s availability.     

Association analyses of 249,796 individuals reveal 18 new loci associated with body mass index

Obesity is globally prevalent and highly heritable, but its underlying genetic factors remain largely elusive. To identify genetic loci for obesity susceptibility, we examined associations between body mass index and ～ 2.8 million SNPs in up to 123,865 individuals with targeted follow up of 42 SNPs in up to 125,931 additional individuals. We confirmed 14 known obesity susceptibility loci and identified 18 new loci associated with body mass index (P < 5 × 10??), one of which includes a copy number variant near GPRC5B. Some loci (at MC4R, POMC, SH2B1 and BDNF) map near key hypothalamic regulators of energy balance, and one of these loci is near GIPR, an incretin receptor. Furthermore, genes in other newly associated loci may provide new insights into human body weight regulation.     

First documentation of Salmincola californiensis in Lake Tahoe, CA–NV, USA

Salmincola californiensis is a parasitic copepod in the Lernaeopodidae family that commonly parasitizes salmonid fishes ( Oncorhynchus spp.) by attaching near the fins and on gill filaments. Historically their distribution was limited to streams that emptied into the Pacific Ocean. During the summer of 2006, several rainbow trout ( Oncorhynchus mykiss ) captured in Lake Tahoe were infested with S. californiensis . This is the first known record of S. californiensis in Lake Tahoe.     

Occurrence, distribution and nature of neuropeptide Y in the rat pancreas

Significant quantities of a newly discovered peptide, neuropeptide Y, were found in the rat pancreas, where they were localized to nerves in the exocrine parenchyma and around arterial and ductal structures. Although unaffected by surgical parasympathectomy, the periarterial and periductal nerves were abolished by chemical sympathectomy, suggesting that NPY is partially costored with sympathetic transmitters in nerve fibers.     

Oscillations of intracellular Ca2+ in mammalian cardiac muscle

Contraction of cardiac muscle depends on a transient rise of intracellular calcium concentration ([Ca2+]i) which is initiated by the action potential. It has, however, also been suggested that [Ca2+]i can fluctuate in the absence of changes in membrane potential. The evidence for this is indirect and comes from observations of (1) fluctuations of contractile force in intact cells, (2) spontaneous cellular movements, and (3) spontaneous contractions in cells which have been skinned to remove the surface membrane. The fluctuations in force are particularly prominent when the cell is Ca2+-loaded, and have been attributed to a Ca2+-induced Ca2+ release from the sarcoplasmic reticulum. In these conditions of Ca2+-loading the normal cardiac contraction is followed by an aftercontraction which has been attributed to the synchronization of the fluctuations. The rise of [Ca2+]i which is thought to underlie the aftercontraction also produces a transient inward current. This current, which probably results from a Ca2+-activated nonspecific cation conductance, has been implicated in the genesis of various cardiac arrhythmias. However, despite the potential importance of such fluctuations of [Ca2+]i their existence has, so far, only been inferred from tension measurements. Here we present direct measurements of such oscillations of [Ca2+]i.     

EEG and sleep in aged hospitalized patients with senile dementia: 24-h recordings

Polygraphic recordings of wake and sleep were performed on 10 partly bed-ridden, severely deteriorated patients with senile dementia. Compared with healthy elderly persons these subjects showed less SWS (slow wave sleep, characterized by high amplitude, slow EEG waves), less REM sleep (rapid eye movement sleep, usually accompanied by dream activity) and poorly organized stage 2 sleep (no sleep spindles, i.e. phasic EEG activity with a frequency of 12-14 Hz). Six of the 10 patients had no dominant alpha rhythm during wakefulness; this seemed to be related to their more deteriorated clinical state, to still less SWS and REM sleep and more time spent in stage 2. The basic NREM-REM cycle of sleep, i.e. the regular alternation between non-REM- and REM-periods, could still be distinguished, however, and showed similar average temporal characteristics as in healthy old and younger people. Similarly, although sleep was severely fragmented in most patients and many sleep episodes occurred during the day, the day-night alternation of wakefulness and sleep was maintained in the sample as a whole.     

Neuropeptide Y in the guinea-pig biliary tract

High concentrations of neuropeptide Y (NPY) have been demonstrated in the gall bladder (16.7 +/- 5.4 pmol/g), cystic duct (25.4 +/- 9.2 pmol/g) and common bile duct (54.7 +/- 11.5 pmol/g) of the guinea-pig using a recently developed radioimmunoassay. Immunoreactive NPY containing nerves were demonstrated in all layers of the biliary tree using immunocytochemistry, being particularly dense in the myenteric and mucosal plexuses.     

Influence of pinealectomy on serum estrogen and progesterone levels in blind-anosmic female rats

Summary Previous studies show that the suppression of gonadal function in blind-anosmic rats is dependent on the pineal gland. The present results demonstrate that in young female rats both the pineal gland and dual sensory deprivation have additional independent antigonaldal effects.This work was partially supported by state institutional funds and by NSF grant No. PCM 74-06276-276-A02. The radioimmunoassays of the steroids were carried out with the aid of the Radioimmunoassay Core which is supported by USPHS grant No. 1T30 HD-10202. We also thank Constance Stahl for typing assistance.     

Identification ofTrypanosoma theileri as a contaminant in primary cultures of bovine retina

Summary T. theileri has been isolated from primary cultures of bovine retina and subcultered successfully for 2 passages in sub-confluent cultures. When cultures reached confluency no trypomastigotes or epimastigotes could be detected and attempts to recover trypanosomes from these cultures were unsuccessful. The presence of intracellular forms could not formally be excluded.We wish to thank Dr S. Dershko, Division of Meat Inspection, Health of Animals Branch, Department of Agriculture (Canada) and Intercontinental Packers, Ltd. for their assistance in obtaining the freshest possible specimens. The skillful technical assistance of Mrs J. Graham is also gratefully acknowledged. This investigation was supported by the M. R. C. of Canada.     

The Phaeodactylum genome reveals the evolutionary history of diatom genomes

Diatoms are photosynthetic secondary endosymbionts found throughout marine and freshwater environments, and are believed to be responsible for around one-fifth of the primary productivity on Earth. The genome sequence of the marine centric diatom Thalassiosira pseudonana was recently reported, revealing a wealth of information about diatom biology. Here we report the complete genome sequence of the pennate diatom Phaeodactylum tricornutum and compare it with that of T. pseudonana to clarify evolutionary origins, functional significance and ubiquity of these features throughout diatoms. In spite of the fact that the pennate and centric lineages have only been diverging for 90 million years, their genome structures are dramatically different and a substantial fraction of genes ( approximately 40%) are not shared by these representatives of the two lineages. Analysis of molecular divergence compared with yeasts and metazoans reveals rapid rates of gene diversification in diatoms. Contributing factors include selective gene family expansions, differential losses and gains of genes and introns, and differential mobilization of transposable elements. Most significantly, we document the presence of hundreds of genes from bacteria. More than 300 of these gene transfers are found in both diatoms, attesting to their ancient origins, and many are likely to provide novel possibilities for metabolite management and for perception of environmental signals. These findings go a long way towards explaining the incredible diversity and success of the diatoms in contemporary oceans.