Optimal stomatal conductance in relation to photosynthesis in climatically contrasting Eucalyptus species under drought

Models of stomatal conductance (g_s) are based on coupling between g_s and CO₂ assimilation (A_net), and it is often assumed that the slope of this relationship (‘g₁’) is constant across species. However, if different plant species have adapted to different access costs of water, then there will be differences in g₁ among species. We hypothesized that g₁ should vary among species adapted to different climates, and tested the theory and its linkage to plant hydraulics using four Eucalyptus species from different climatic origins in a common garden. Optimal stomatal theory predicts that species from sub‐humid zones have a lower marginal water cost of C gain, hence lower g₁ than humid‐zone species. In agreement with the theory that g₁ is related to tissue carbon costs for water supply, we found a relationship between wood density and g₁ across Eucalyptus species of contrasting climatic origins. There were significant reductions in the parameter g₁ during drought in humid but not sub‐humid species, with the latter group maintaining g₁ in drought. There are strong differences in stomatal behaviour among related tree species in agreement with optimal stomatal theory, and these differences are consistent with the economics involved in water uptake and transport for carbon gain.     

Habitat-associated morphological divergence in two Neotropical fish species

We examined intraspecific morphological diversification between river channel and lagoon habitats for two Neotropical fish ( Bryconops caudomaculatus , Characidae; Biotodoma wavrini , Cichlidae). We hypothesized that differences between habitats (e.g. flow regime, foraging opportunities) might create selective pressures resulting in morphological divergence between conspecific populations. We collected fish from four channel-lagoon habitat pairs in the Río Cinaruco, Venezuela, and compared body morphology using geometric morphometrics. There were two aspects of divergence in both species: (1) placement of maximum body depth and (2) orientation of the mouth. For both species, maximum body depth was positioned more anteriorly (i.e. fusiform) in the river channel than in lagoons. Both species exhibited a relatively terminal mouth in lagoons compared to the channel. The mouth of B. caudomaculatus was relatively upturned, whereas the mouth of B. wavrini was relatively subterminal, in channel habitats. Observed morphological patterns are consistent with functional morphological principles suggesting adaptive divergence. We also show that spatial distance between habitats, presumably reflecting rates of population mixing, appears to have constrained diversification. For both species, morphological divergence increased with distance between habitats. Thus morphological divergence between channel and lagoon habitats apparently reflects a balance between diversification driven by natural selection, and homogenization driven by population mixing.  © 2003 The Linnean Society of London, Biological Journal of the Linnean Society , 2003, 80 , 689–698.     

Intra-articular implantation of autologous bone marrow–derived mesenchymal stromal cells to treat knee osteoarthritis: a randomized,triple-blind,placebo-controlled phase 1/2 clinical trial

Background

The intra-articular implantation of mesenchymal stromal cells (MSCs) as a treatment for knee osteoarthritis (OA) is an emerging new therapy. In this study, patients with knee OA received intra-articular implantations of autologous bone marrow–derived MSCs. We sought to assess the safety and efficacy of this implantation.

Effectiveness and specificity of a classroom-based group intervention in children and adolescents exposed to war in Lebanon

The purpose of this study was to examine the effectiveness and specificity of a classroom-based psychosocial intervention after war. All students (n=2500) of six villages in Southern Lebanon designated as most heavily exposed to war received a classroom-based intervention delivered by teachers, consisting of cognitive-behavioural and stress inoculation training strategies. A random sample of treated students (n=101) and a matched control group (n=93) were assessed one month post-war and one year later. Mental disorders and psychosocial stressors were assessed using the Diagnostic Interview for Children and Adolescents - Revised with children and parents. War exposure was measured using the War Events Questionnaire. The prevalence of major depressive disorder (MDD), separation anxiety disorder (SAD) and post-traumatic stress disorder (PTSD) was examined pre-war, one month post-war (pre-intervention), and one year post-war. Specificity of treatment was determined by rating teachers’ therapy diaries. The rates of disorders peaked one month post-war and decreased over one year. There was no significant effect of the intervention on the rates of MDD, SAD or PTSD. Post-war MDD, SAD and PTSD were associated with pre-war SAD and PTSD, family violence parameters, financial problems and witnessing war events. These findings have significant policy and public health implications, given current practices of delivering universal interventions immediately post-war.     

A microRNA signature associated with chondrogenic lineage commitment

Generating appropriate cartilage for clinical applications to heal skeletal tissue loss is a major health concern. In this regard, cell-based approaches offer a potential therapeutic strategy for cartilage repair, although little is known about the precise mechanism of chondrogenesis. Unrestricted somatic stem cell (USSC) is considered as a suitable candidate because of its potential for differentiating into multiple cell types. Recent studies show that microRNAs (miRNAs) are involved in several biological processes including development and differentiation. To identify the chondro-specific miRNA signature, miRNA patterns of USSCs and differentiated chondrocytes were investigated using microarrays and validation by qPCR. Prior to these analyses, chondrogenic commitment of differentiated USSCs was verified by immunocytochemistry, specific staining and evaluation of some main chondrogenic marker genes. Various in silico explorations (for both putative targets and signalling pathways) and empirical analyses (miRNA transfections followed by qPCR of some chondrogenic indicators) were carried out to support our results. Transient modulation of multiple chondro-miRs (such as mir-630, mir-624 and mir-376) with chondrocyte targets (such as TGFbR, MAP3K, collagens, SMADs and cadherins) as mediators of chondrogenic signalling pathways including cell-cell interactions, TGF-beta, and MAPK signalling suggests a mechanism for genetic induction of chondrogenic differentiation. In conclusion, this research reveals more details about the allocation of USSCs into the chondrocytes through identification of miRNA signature which modulates targets and pathways required for chondrogenic lineage and could provide guidelines for future clinical treatments and anti-miRNA therapies.     

Autologous bone marrow–derived CD133 cells with core decompression as a novel treatment method for femoral head osteonecrosis: a pilot study

Background

Avascular necrosis (AVN) of femoral head is a progressive bone disease due to ischemia of femoral head; patients experience pain and they can not do normal activity. There is not an effective way to treat the cause of this disease. In recent studies, treatment of this disease using pluripotent stem cell–derived mesenchyme is safe and effective, but this method needs more investigation. In this study, the safety and efficacy of CD133+ cells were evaluated as a novel method of stem cell therapy to treat AVN.

A step towards understanding plant responses to multiple environmental stresses: a genome‐wide study

In natural habitats, especially in arid areas, plants are often simultaneously exposed to multiple abiotic stresses, such as salt, osmotic and heat stresses. However, most analyses of gene expression in stress responses examine individual stresses. In this report, we compare gene expression in individual and combined stresses. We show that combined stress treatments with salt, mannitol and heat induce a unique pattern of gene expression that is not a simple merge of the individual stress responses. Under multiple stress conditions, expression of most heat and salt stress‐responsive genes increased to levels similar to or higher than those measured in single stress conditions, but osmotic stress‐responsive genes increased to lower levels. Genes up‐regulated to higher levels under multiple stress condition than single stress conditions include genes for heat shock proteins, heat shock regulators and late embryogenesis abundant proteins (LEAs), which protect other proteins from damage caused by stresses, suggesting their importance in multiple stress condition. Based on this analysis, we identify candidate genes for engineering crop plants tolerant to multiple stresses.     

Functional response of the ladybird, Cydonia vicina nilotica to cowpea aphid, Aphis craccivora in the laboratory

The functional response of Cydonia vicina nilotica Muls. （Coleoptera： Coccinellidae） to six densities of Aphis craccivora Koch （Homoptera： Aphididae） nymphs on broad bean （Viciafaba Linn.） was investigated in the laboratory. A linear relationship between the rate of consumption and prey density was observed with r^2 values between 0.58 and 0.97. Plotting prey density against prey killed by four larval instars, and adult males and females of C. vicina nilotica fit well with the type Ⅱ model of Holling＇ s disc equation. Adult females consumed the highest number of prey, followed by fourth instars and adult males. Based on the functional response data, the model predicts a maximum of 144.9, 116.3, 86.2, 80.0, 72.5 and 20.0 nymphs to be consumed per day by an individual adult female, fourth instar, adult male, third, second and first instars, respectively. The differences in the responses of the predator to aphid densities are discussed.     

Twelve variable microsatellite loci for the North American medicinal leech,Macrobdella decora

We isolated and characterized 12 microsatellite loci for the North American medicinal leech, Macrobdella decora. Macrobdella decora is abundant in central and northern North American freshwater systems. The resulting microsatellite library, the first for any species of leech or any clitellate annelid, demonstrates the efficacy of this type of analysis on unexploited leech populations and should serve as a baseline for comparison with other species, notably the commercially important and threatened European medicinal leech, Hirudo medicinalis.