Fine root responses to temporal nutrient heterogeneity and competition in seedlings of two tree species with different rooting strategies

There is little direct evidence for effects of soil heterogeneity and root plasticity on the competitive interactions among plants. In this study, we experimentally examined the impacts of temporal nutrient heterogeneity on root growth and interactions between two plant species with very different rooting strategies: Liquidambar styraciflua (sweet gum), which shows high root plasticity in response to soil nutrient heterogeneity, and Pinus taeda (loblolly pine), a species with less plastic roots. Seedlings of the two species were grown in sandboxes in inter‐ and intraspecific combinations. Nutrients were applied in a patch either in a stable (slow‐release) or in a variable (pulse) manner. Plant aboveground biomass, fine root mass, root allocation between nutrient patch and outside the patch, and root vertical distribution were measured. L. styraciflua grew more aboveground (40% and 27% in stable and variable nutrient treatment, respectively) and fine roots (41% and 8% in stable and variable nutrient treatment, respectively) when competing with P. taeda than when competing with a conspecific individual, but the growth of P. taeda was not changed by competition from L. styraciflua. Temporal variation in patch nutrient level had little effect on the species’ competitive interactions. The more flexible L. styraciflua changed its vertical distribution of fine roots in response to competition from P. taeda, growing more roots in deeper soil layers compared to its roots in conspecific competition, leading to niche differentiation between the species, while the fine root distribution of P. taeda remained unchanged across all treatments. Synthesis. L. styraciflua showed greater flexibility in root growth by changing its root vertical distribution and occupying space of not occupied by P. taeda. This flexibility gave L. styraciflua an advantage in interspecific competition.     

中国主要河流鱼类分布及其种类多样性与流域特征的关系

对中国13条主要河流淡水鱼类分布进行的系统聚类分析结果表明,分异最小的是闽江与九龙江。瓯江与钱塘江、淮河与黄河、东北的水系分别较早聚为一类。相异系数在0.60～0.69时分为三类: 东北的水系、黄河到珠江间的水系和云南的元江。淡水鱼种类数与流域特征的相关和回归分析揭示了：鱼种数分别与河流流域面积、年平均流量呈显著或极显著的正相关,单位干流长和单位流域面积的鱼种类数分别与河流径流深、比降呈显著或极显著的正相关, 而与河流平均纬度呈显著负相关。主成分分析得到的第一和第二主成分分别综合反映了河流鱼种类数和相对种类数与河流特征值的关系。     

3-Ketoglycoside-mediated metabolism of sucrose in E. coli as conferred by genes from Agrobacterium tumefaciens

Escherichia coli strains that did not have the ability to use sucrose as a sole carbon source gained this ability after receiving a cloned fragment of DNA from Agrobacterium tumefaciens. No invertase was detected in the sucrose-metabolizing E. coli, but evidence for the activity of certain enzymes, known to be produced by biotype 1 strains of Agrobacterium, were found. Evidence was found for the presence of d-glucoside 3-dehydrogenase (G3DH) and α-3-ketoglucosidase. The activity of enzyme extracts on 3-ketosucrose also indicated that 3-ketoglucose reductase, or some enzyme that acts on 3-ketoglucose, was present in the Suc⁺ E. coli as well. The fragment was found to complement a G3DH mutant of A. tumefaciens and was also found to confer chemotaxis towards sucrose in E. coli. Received: 13 September 1996 / Received revision: 15 January 1997 / Accepted: 24 January 1997     

Exogenous sucrose treatment accelerates postharvest tomato fruit ripening through the influence on its metabolism and enhancing ethylene biosynthesis and signaling

The role of sucrose as a signal molecule in plants was in debate for a long time, until recently, it gradually becomes more prominently accepted. Sucrose plays roles in a vast array of developmental processes in plants, however, its function in fruit ripening has not been well elucidated. In this study, the influence of exogenous sucrose treatment (500 mM) on postharvest tomato fruit ripening was investigated. It was found that, in comparison with mannitol treatment (500 mM, set as control), sucrose accelerated the ripening process with higher levels of respiration rate and ethylene production during the storage. Sucrose treatment up-regulated its biosynthetic genes, whilst stimulated expressions of genes encoding degradation related enzymes in the fruits. However, higher sucrose content was observed in sucrose-treated fruits only in the first few days. In addition, sucrose application had minor effect on the contents of its degrading products, glucose and fructose. Moreover, exogenous sucrose treatment up-regulated expressions of ethylene biosynthetic genes, and promoted ethylene signal transduction via influencing critical genes of the signaling pathway in different patterns. These results indicate that sucrose stimulates tomato fruit ripening may through mediating its own metabolism, which facilitates nutrients fluxes and metabolic signaling molecules activation, and also by enhancing ethylene biosynthesis and signal transduction.     

Attenuation of Acute Phase Injury in Rat Intracranial Hemorrhage by Cerebrolysin that Inhibits Brain Edema and Inflammatory Response

The outcome of intracerebral hemorrhage (ICH) is mainly determined by the volume of the hemorrhage core and the secondary brain damage to penumbral tissues due to brain swelling, microcirculation disturbance and inflammation. The present study aims to investigate the protective effects of cerebrolysin on brain edema and inhibition of the inflammation response surrounding the hematoma core in the acute stage after ICH. The ICH model was induced by administration of type VII bacterial collagenase into the stratum of adult rats, which were then randomly divided into three groups: ICH + saline; ICH + Cerebrolysin (5 ml/kg) and sham. Cerebrolysin or saline was administered intraperitoneally 1 h post surgery. Neurological scores, extent of brain edema content and Evans blue dye extravasation were recorded. The levels of pro-inflammatory factors (IL-1β, TNF-α and IL-6) were assayed by Real-time PCR and Elisa kits. Aquaporin-4 (AQP4) and tight junction proteins (TJPs; claudin-5, occludin and zonula occluden-1) expression were measured at multiple time points. The morphological and intercellular changes were characterized by Electron microscopy. It is found that cerebrolysin (5 ml/kg) improved the neurological behavior and reduced the ipsilateral brain water content and Evans blue dye extravasation. After cerebrolysin treated, the levels of pro-inflammatory factors and AQP4 in the peri-hematomal areas were markedly reduced and were accompanied with higher expression of TJPs. Electron microscopy showed the astrocytic swelling and concentrated chromatin in the ICH group and confirmed the cell junction changes. Thus, early cerebrolysin treatment ameliorates secondary injury after ICH and promotes behavioral performance during the acute phase by reducing brain edema, inflammatory response, and blood–brain barrier permeability.     

Estimating the Population Size and Genetic Diversity of Amur Tigers in Northeast China

Over the past century, the endangered Amur tiger (Panthera tigris altaica) has experienced a severe contraction in demography and geographic range because of habitat loss, poaching, and prey depletion. In its historical home in Northeast China, there appears to be a single tiger population that includes tigers in Southwest Primorye and Northeast China; however, the current demographic status of this population is uncertain. Information on the abundance, distribution and genetic diversity of this population for assessing the efficacy of conservation interventions are scarce. We used noninvasive genetic detection data from scats, capture-recapture models and an accumulation curve method to estimate the abundance of Amur tigers in Northeast China. We identified 11 individual tigers (6 females and 5 males) using 10 microsatellite loci in three nature reserves between April 2013 and May 2015. These tigers are confined primarily to a Hunchun Nature Reserve along the border with Russia, with an estimated population abundance of 9–11 tigers during the winter of 2014–2015. They showed a low level of genetic diversity. The mean number of alleles per locus was 2.60 and expected and observed heterozygosity were 0.42 and 0.49, respectively. We also documented long-distance dispersal (~270 km) of a male Amur tiger to Huangnihe Nature Reserve from the border, suggesting that the expansion of neighboring Russian populations may eventually help sustain Chinese populations. However, the small and isolated population recorded by this study demonstrate that there is an urgent need for more intensive regional management to create a tiger-permeable landscape and increased genetic connectivity with other populations.     

Phylogenetic relationship of Clauseneae (Rutaceae) inferred from plastid and nuclear DNA data and taxonomic implication for some major taxa

Using sequences of the nuclear ribosomal ITS region as well as the chloroplast DNA trnL‐trnF and atpB‐rbcL regions, this study aims to provide further insight into the phylogenetic relationships within Clauseneae and its relationship to Citreae (Rutaceae). Using maximum likelihood (ML) and Bayesian inference (BI), we reconstructed the phylogeny of Clauseneae based on trnL‐F, atpB‐rbcL and ITS sequences. Our data matrix contained 91 accessions, representing 72 species and varieties from 31 genera and two outgroups, including new and extensive sampling of species and varieties representing four genera in the tribe Clauseneae. In the subfamily Aurantioideae, six major clades were resolved with strong support: 1) Micromelum clade: Micromelum; 2) Glycosmis clade: Glycosmis; 3) Bergera clade: Murraya sect. Bergera; 4) Clausena clade: Clausena; 5) Murraya clade: Murraya sect. Murraya + Merrillia; 6) Citreae clade: Citreae. Micromelum, Glycosmis, Clausena and Merrillia were confirmed as monophyletic. In contrast, Murraya s.l. was reconstructed as polyphyletic. Murraya sect. Bergera clustered with Clausena while Murraya sect. Murraya and Merrillia together formed a clade that is sister to the tribe Citreae. All members from Citreae were clustered into a natural group. The genus Micromelum was found to be primitive in this subfamily and more close to Glycosmis. Based on the phylogeny and morphological characters, we discuss the taxonomy of some members of Clauseneae and conclude that the current tribal and generic classification need further revision.     

CRNDE enhances neuropathic pain via modulating miR-136/IL6R axis in CCI rat models

Neuropathic pain has been reported as a type of chronic pain due to the primary dysfunction of the somatosensory nervous system. It is the most serious types of chronic pain, which can lead to a significant public health burden. But, the understanding of the cellular and molecular pathogenesis of neuropathic pain is barely complete. Long noncoding RNAs (lncRNAs) have recently been regarded as modulators of neuronal functions. Growing studies have indicated lncRNAs can exert crucial roles in the development of neuropathic pain. Therefore, our present study focused on the potential role of the lncRNA Colorectal Neoplasia Differentially Expressed (CRNDE) in neuropathic pain progression. Firstly, a chronic constrictive injury (CCI) rat model was built. CRNDE was obviously increased in CCI rats. Interestingly, overexpression of CRNDE enhanced neuropathic pain behaviors. Neuroinflammation was induced by CRNDE and as demonstrated, interleukin-10 (IL-10), IL-1, IL-6, and tumor necrosis factor-α (TNF-α) protein levels in CCI rats were activated by LV-CRNDE. For another, miR-136 was obviously reduced in CCI rats. Previously, it is indicated that miR-136 participates in the spinal cord injury via an inflammation in a rat model. Here, firstly, we verified miR-136 could serve as CRNDE target. Loss of miR-136 triggered neuropathic pain remarkably via the neuroinflammation activation. Additionally, IL6R was indicated as a target of miR-136 and miR-136 regulated its expression. Subsequently, we confirmed that CRNDE could induce interleukin 6 receptor (IL6R) expression positively. Overall, it was implied that CRNDE promoted neuropathic pain progression via modulating miR-136/IL6R axis in CCI rat models.     

Defects and rescue of the minor salivary glands in Eda pathway mutants

Despite their importance to oral health, the mechanisms of minor salivary gland (SG) development are largely unexplored. Here we present in vivo and in vitro analyses of developing minor SGs in wild type and mutant mice. Eda, Shh and Fgf signalling pathway genes are expressed in these glands from an early stage of development. Developing minor SGs are absent in Eda pathway mutant embryos, and these mice exhibit a dysplastic circumvallate papilla with disrupted Shh expression. Supplementation of Eda pathway mutant minor SG explants with recombinant EDA rescues minor SG induction. Supplementation with Fgf8 or Shh, previously reported targets of Eda signalling, leads to induction of gland like structures in a few cases, but these fail to develop into minor SGs.