Soil seed banks along elevational gradients in tropical, subtropical and subalpine forests in Yunnan Province, southwest China

Soil seed banks are a vital part of ecosystems and influence community dynamics and regeneration. Although soil seed banks in different habitats have been reported, how soil seed banks vary with elevational gradients in different climatic zones is still unknown. This paper investigates seed density, species composition and nonconstituent species of forest soil seed banks in Yunnan Province, southwest China. Similarity between the soil seed bank and standing vegetation was also examined. We collected soil samples from sites spanning 12 elevations in tropical rain forests, subtropical evergreen broad-leaved forests and subalpine coniferous forests, and transported them to a glasshouse for germination trials for species identification. The soil seed banks of tropical and subtropical forests had much higher seed densities and species richness than those of subalpine forests. Seeds of woody species dominated the soil seed banks of tropical and subtropical forests, while herbs dominated those of subalpine forests. The nonconstituent species in the soil seed banks were all herbs and were most abundant in tropical forests, followed by subtropical forests but were completely absent from subalpine forests.

The RING-H2 protein RNF11 is overexpressed in breast cancer and is a target of Smurf2 E3 ligase

The breast cancer-associated T2A10 clone was originally isolated from a cDNA library enriched for tumour messenger ribonucleic acids. Our survey of 125 microarrayed primary tumour tissues using affinity purified polyclonal antibodies has revealed that corresponding protein is overexpressed in invasive breast cancer and is weakly expressed in kidney and prostate tumours. Now known as RNF11, the gene encodes a RING-H2 domain and a PY motif, both of which mediate protein–protein interactions. In particular, the PPPPY sequence of RNF11 PY motif is identical to that of Smad7, which has been shown to bind to WW domains of Smurf2, an E3 ubiquitin ligase that mediates the ubiquitination and degradation of the TGFβ receptor complex. Using various mutants of RNF11 in GST pulldown and immunoprecipitation assays, we found that RNF11 interacts with Smurf2 through the PY motif, leading to ubiquitination of both proteins. Smurf2 plays an active role in the repression of TGFβ signalling, and our data indicate that overexpression of RNF11, through its interaction with Smurf2, can restore TGFβ responsiveness in transfected cells.

Involvement of Ets transcription factors and targets in osteoblast differentiation and matrix mineralization

The osteoblast-like MC3T3-E1 cell line provides an excellent in vitro model of bone development. This system undergoes three orderly time-dependent phases characterized by proliferating preosteoblasts, matrix accumulation by postmitotic differentiating osteoblasts, and mineralization of the matrix, which results in the formation of multilayered bone nodules. The Ets family transcription factors regulate genetic programs that affect the proliferation and differentiation of osteoblasts. Of the eight Ets family transcription factors examined by our laboratory, only Etsl and Ets2 were found to be expressed at significant levels in this osteogenic system. Etsl is expressed in proliferating preosteoblastic cells, whereas Ets2, silent during this phase, is expressed by differentiating and mature osteoblasts. In addition, the expression of Etsl can be induced in MC3T3-E1 and fetal rat calvaria cells by retinoic acid (RA) which is known to exert profound effects on skeletal growth and development and bone turnover and induce specific cellular responses in bone cells. Thus, the multiple functions of RA in bone cells are likely to be mediated in part by Etsl. We show that the expression of Ets2 precedes and then parallels osteopontin expression and that the OPN promoter contains Ets binding sites and is a transcriptional target of Ets2. In order to identify other potential Ets target genes, we analyzed promoter regions of genes revealed by serial analysis of gene expression as present in the differentiation stage. The functional analysis of these genes has the potential to provide much needed information as to their function in osteogenesis and mineralization of the extracellular matrix and in bone-related diseases.

Effects of simvastatin and enalapril on serum lipoprotein concentrations and left ventricular mass in patients on dialysis. The Perfect Study Collaborative Group

A randomised trial of simvastatin and enalapril in patients with chronic renal failure on dialysis: effects on serum lipoprotein concentrations and left ventricular mass. Left ventricular hypertrophy and abnormalities of lipoprotein metabolism are both possible contributors to the high risk of cardiovascular death in patients with chronic renal failure on dialysis. We investigated the effects of simvastatin on lipid and lipoprotein concentrations and the effects of enalapril on left ventricular mass in 107 patients receiving haemodialysis or continuous ambulatory peritoneal dialysis. Patients were randomised in a factorial design to receive simvastatin (10 mg daily) or placebo and enalapril (2.5-5 mg daily) or placebo. During follow-up, there was a significant excess of patients withdrawn from enalapril because of hypotension (2p = 0.002), and after 6 months only 55% of those assigned enalapril were still on treatment. From baseline to 6 months, there were no statistically significant differences in left ventricular mass or left ventricular dimensions between patients assigned enalapril and those assigned placebo. Among the patients assigned simvastatin, total cholesterol was reduced by 13% (2p = 0.001), LDL cholesterol was reduced by 17% (2p = 0.003) and apolipoprotein B was reduced by 12% (2p = 0.005) compared to patients assigned placebo. There were borderline significant (2p = 0.05 to 0.08) reductions in VLDL cholesterol, total triglyceride and VLDL triglycerides of 26%, 12% and 17% respectively. Large-scale trials are now required to determine whether reductions in lipid and lipoprotein concentrations confer a reduction in coronary heart disease morbidity and mortality in patients on dialysis.

Bulk isolation and identification of fish genes by cDNA clone tagging

The fish has long been a popular research model for various disciplines in the life sciences, but its molecular biology remains largely unexplored, and the number of fish genes identified at present is still limited. To increase the repertoire of fish genes to facilitate further research, we have embarked on cDNA clone tagging studies in several teleosts. The basic procedure is partial sequencing of randomly selected cDNA clones by a single sequencing reaction to obtain nucleotide sequences of about 200 to 300 bp for each clone. These partial DNA sequences can be used as tags to identify fish homologous genes by searching for sequence similarity in DNA databases. By this method, we have sequenced a total of 265 clones from pituitary and liver cDNA libraries from five species of fish and identified 83 clones encoding 55 different genes. These 55 genes are described for the first time in their species, and 37 of them are described for the first time in fish. These preliminary data indicate that cDNA clone tagging is useful for rapidly increasing the number and availability of genes in teleosts. Several applications of these tagged random clones are discussed.

A simple sleep recorder for clinical situations

In spite of the importance of sleep disorder in clinical practice, and the widespread use of hypnotics (Johnson and Clift, 1968), no simple technique for objectively recording sleep patterns in clinical situations is available. EEG recording during sleep (Oswald, 1969) or the use of motility beds (Hinton and Marley, 1959) are sophisticated techniques for use largely in laboratory conditions. Many clinical investigations of sleep disorders (Haider, 1968) or trials of hypnotics (Matthewet al., 1969), rely upon subjective assessments of the quality and duration of sleep by the patient, together with a night nurse's assessment largely based upon observed restlessness. Errors in the estimation of duration of sleep are particularly likely to occur in depressed patients where the illness itself produces an altered awareness of the passage of time (Orme, 1969), while nursing observations on sleep are unreliable (Kupferet al., 1970). Similarly patients suffering from insomnia due to chronic pain or secondary to diffuse organic cerebral disease may misjudge the passage of time and their period of wakefulness during the hours of isolation during the night. Another group who particularly misjudge the passage of time in relation to sleep are those obsessional personalities, with overvalued ideas about the necessity for adequate sleep, who account for so many of the requests for hypnotics in general practice. Hypnotic drug-dependent patients overvalue their insomnia during their withdrawal from drugs, and again make inaccurate assessment of their sleep patterns.