The role of the soil seed and seedling bank in the regeneration of diverse plant communities in the subtropical Ailao Mountains,Southwest China

We compared species composition and diversity of the soil seed and seedling banks in three secondary vegetation types (shrubland, Populus bonatii forest, Lithocarpus regrowth forest) and a primary old-growth forest in the subtropical Ailao Mountains of southwestern China to clarify the importance of seed and seedling banks for forest dynamics. The average species richness was the highest in soil samples from the shrubland (26.80 ± 1.98), and the lowest from the primary forest (9.93 ± 0.50). The density of germinable tree seeds increased from the secondary vegetation to the primary forest, and the density of shrub, forb, and graminoid seeds decreased significantly. The most abundant seedlings recorded in soil samples were light-demanding species in the shrubland and Populus bonatii forest. For ground flora, the number of shrub seedlings strongly decreased with the increase in stand age, and shade-tolerant tree seedlings tended to increase. The species similarity between the seed bank and the aboveground vegetation in all sites was low (Sørensen’s index = 0.11–0.33), however, the shrubland had higher similarity compared with the other three plant communities. In the primary forest, light-demanding woody species dominated in soil seed banks, while shade-tolerant species dominated in the overstory and the forest floor. In the primary forest, seedlings of dominant tree species were rare in the understory, and no seeds of the dominant species were found in the soil. Results indicated that the early stages of vegetation recovery should take into account the possibility of recovering soil seed bank processes. However, colonization and establishment of tree seedlings will be difficult once a primary forest is destroyed.     

The Content of Elements in Rainwater and its Relation to the Frequency of Hospitalization for Diabetes and Obesity in Opole Voivodship,Poland, During 2000–2002

Environmental factors significantly influence the incidence and course of metabolic syndrome diseases such as diabetes and obesity. The content of elements in rainwater is an indirect indicator of their presence in dust suspended in the air. In this paper we present the relationships between the content of selected elements in rainwater and hospitalization frequencies due to diabetes (E10–E13) and obesity (E66). It was assumed that the hospitalization frequency could be taken as a measure of deterioration of the metabolic process in the course of diabetes and its complications. The observations concerned the population of Opole Voivodeship, Poland (one million inhabitants), distributed in small communities of 44,000 to 151,000 inhabitants during the years 2000–2002. In cases of diabetes E10–E13 for all subjects relevant correlation indicators were found for chromium (r = 0.71), cadmium (r = 0.65), and lead (r = 0.66). Borderline relevance was seen for copper (r = 0.57) and zinc (r = 056). For diabetic men the statistically relevant correlations were chromium (r = 0.79), lead (r = 0.77), cadmium (r = 0.74), copper (r = 0.70), chloride (r = 0.69), zinc (r = 0.68), and iron (r = 0.64). For women the only relevant correlations were chromium (r = 0.62) and cadmium (r = 0.55). No significant correlations were found in obese individuals of both sexes.     

A B Functional Gene Cloned from Lily Encodes an Ortholog of <Emphasis Type="BoldItalic">Arabidopsis PISTILLATA</Emphasis> (<Emphasis Type="BoldItalic">PI</Emphasis>)

The classical ABC model proposed for flower development in Arabidopsis and Antirrhinum appropriately sheds light on the biological process of flower development and differentiation and serves in manipulating the floral structure of other important ornamental plants. In this study, LLGLO1, a B functional gene from Lilium longiflorum was isolated and characterized. RT-PCR analysis elucidated that temporal and spatial expression pattern of LLGLO1. This putative gene was strongly expressed in 1, 2, and 3 whorl organs, i.e., outer whorl tepals, inner whorl tepals, and stamens. Genetic effect of LLGLO1 was assayed by ectopic expression in model plant Arabidopsis. Transformed plants showed homeotic transformation of sepals into petaloid sepals in the first whorl, which is similar to the transgenic plants of 35S::PI. So LLGLO1 was one member of GLO/PI sub-family gene to function in flower development.     

Selecting high-dimensional mixed graphical models using minimal AIC or BIC forests

Background  

Chow and Liu showed that the maximum likelihood tree for multivariate discrete distributions may be found using a maximum weight spanning tree algorithm, for example Kruskal's algorithm. The efficiency of the algorithm makes it tractable for high-dimensional problems.     

ARTEMIS stabilizes the genome and modulates proliferative responses in multipotent mesenchymal cells

Background  

Unrepaired DNA double-stranded breaks (DSBs) cause chromosomal rearrangements, loss of genetic information, neoplastic transformation or cell death. The nonhomologous end joining (NHEJ) pathway, catalyzing sequence-independent direct rejoining of DSBs, is a crucial mechanism for repairing both stochastically occurring and developmentally programmed DSBs. In lymphocytes, NHEJ is critical for both development and genome stability. NHEJ defects lead to severe combined immunodeficiency (SCID) and lymphoid cancer predisposition in both mice and humans. While NHEJ has been thoroughly investigated in lymphocytes, the importance of NHEJ in other cell types, especially with regard to tumor suppression, is less well documented. We previously reported evidence that the NHEJ pathway functions to suppress a range of nonlymphoid tumor types, including various classes of sarcomas, by unknown mechanisms.     

Kinesin-14: the roots of reversal

Kinesin-14 motor proteins step towards microtubule minus ends, in the opposite direction to other kinesins. Work on the still-enigmatic kinesin-14 mechanism published in BMC Structural Biology shows that the carboxyl terminus of the motor head undergoes a dock-undock cycle, like that of plus-end-directed kinesins.     

An Electron Spin Resonance Study for Real-time Detection of Ascorbyl Free Radicals After Addition of Dimethyl Sulfoxide in Murine Hippocampus or Plasma During Kainic Acid-Induced Seizures

Electron spin resonance (ESR)-silent ascorbate solutions generate a detectable, likely concentration-dependent signal of ascorbyl free radicals (AFR) immediately upon addition of a molar excess of dimethyl sulfoxide (DMSO). We aimed to perform quantitative ESR analysis of AFR in real time after addition of DMSO (AFR/DMSO) to evaluate ascorbate concentrations in fresh hippocampus or plasma following systemic administration of kainate in mice. Use of a special tissue-type quartz cell allowed immediate detection of AFR/DMSO ESR spectra in fresh tissues from mice. AFR/DMSO content was increased significantly in fresh hippocampus or plasma obtained during kainate-induced seizures of mice, reaching maximum levels at 90 min after intraperitoneal administration of 50 mg/kg kainic acid. This suggests that oxidative injury of the hippocampus resulted from the accumulation of large amounts of ascorbic acid in the brain after kainic acid administration. AFR/DMSO content measured on an ESR spectrometer can be used for real-time evaluation of ascorbate content in fresh tissue. Due to the simplicity, good performance, low cost and real-time monitoring of ascorbate, this method may be applied to clinical research and treatment in the future.