Studies on acidification of media by Avena stem segments in the presence and absence of gibberellic Acid

The rate of acidification of media by Avena stem segments was studied with a titrimeter. GA₃ increased this rate by an average of 17% if supplied to the segments 90 min prior to measurement. GA₃ inhibited the rate by 15% if supplied 10 min prior to measurement. After 90 min incubation, stimulation of elongation had started; at 10 min, GA₃ had not yet started to stimulate elongation in the segments.     

中国的炭疽杆菌DNA分型及其地理分布

炭疽广泛分布于中国各地,特别是西部地区,并经常造成人畜疾病,在一项合作研究中,用多位点VNTR分析（MLVA）对从1952-1998年自中国主要地理流行区域分离的病人,病畜和土壤等来源的炭疽杆菌进行了基因分型,MLVA分析结果揭示了21种新的基因型,其等位基因组合在以前世界范围分离物的研究中未曾发现,此外,分离物的分群显示,A3b组是地理上最广泛分布的基因组,说明该组可能是中国的“地方流行株”。而来自古丝绸之路重要贸易中心新疆的大量分离株其基因型特别分散。     

MicroRNAs in systemic rheumatic diseases

MicroRNAs (miRNAs) are endogenous, non-coding, single-stranded RNAs about 21 nucleotides in length. miRNAs have been shown to regulate gene expression and thus influence a wide range of physiological and pathological processes. Moreover, they are detected in a variety of sources, including tissues, serum, and other body fluids, such as saliva. The role of miRNAs is evident in various malignant and nonmalignant diseases, and there is accumulating evidence also for an important role of miRNAs in systemic rheumatic diseases. Abnormal expression of miRNAs has been reported in autoimmune diseases, mainly in systemic lupus erythematosus and rheumatoid arthritis. miRNAs can be aberrantly expressed even in the different stages of disease progression, allowing miRNAs to be important biomarkers, to help understand the pathogenesis of the disease, and to monitor disease activity and effects of treatment. Different groups have demonstrated a link between miRNA expression and disease activity, as in the case of renal flares in lupus patients. Moreover, miRNAs are emerging as potential targets for new therapeutic strategies of autoimmune disorders. Taken together, recent data demonstrate that miRNAs can influence mechanisms involved in the pathogenesis, relapse, and specific organ involvement of autoimmune diseases. The ultimate goal is the identification of a miRNA target or targets that could be manipulated through specific therapies, aiming at activation or inhibition of specific miRNAs responsible for the development of disease.     

Frequent coexistence of anti-topoisomerase I and anti-U1RNP autoantibodies in African American patients associated with mild skin involvement: a retrospective clinical study

Introduction  

The presence of anti-topoisomerase I (topo I) antibodies is a classic scleroderma (SSc) marker presumably associated with a unique clinical subset. Here the clinical association of anti-topo I was reevaluated in unselected patients seen in a rheumatology clinic setting.     

Role of ribosomal protein RPS2 in controlling let-7a expression in human prostate cancer

We discovered that an inverse relationship exists in the expression of ras/c-myc and ribosomal protein RPS2 with pre-let-7a-1/let-7a/let-7f miRNA and prostate tumor cell malignancy. Nonmalignant IBC-10a cells expressed low levels of ras/RPS2 and elevated pre-let-7a-1/let-7a/let-7f miRNA, whereas the reverse occurred in malignant PCa-20a and PC-3ML cells. Stable transfection of IBC-10a cells with pBABE.ras and pBABE.RPS2 induced ras, c-myc, and RPS2 expression, whereas the levels of let-7a/let-7f miRNA dropped to near zero. Conversely, in pBABE.pre-let-7a-1 transfected PCa-20a and PC-3ML clones, let-7a/let-7f increased whereas ras, RPS2, and c-myc dropped greater than 5-fold. Electrophoretic mobility shift assays, antibody "supershift" assays and immunoprecipitation assays revealed that RPS2 specifically binds pre-let-7a-1 to block RNA processing. Immunoflourescent studies and Northern blots confirmed that RPS2 complexes with pre-let-7a-1 (i.e., in episomal structures) to block processing to let-7a/let-7f, indicating RPS2 may prevent let-7a miRNA expression to indirectly promote oncogene expression. Functional studies further showed that the colony-forming ability (CFA) and invasive activities of IBC-10a cells were significantly enhanced in pBABE-ras.IBC-10a and pBABE-RPS2-IBC-10a clones. Conversely, with the "knockdown" of ras and RPS2 in malignant PC-3ML cells (i.e., in pLKO.TRC.shRNA.ras.PC3-ML, pLKO.TRC.shRNA.RPS2.PC-3ML transfected cells), there was both a loss of these functions and a loss of tumorigenesis in SCID mice. Likewise, with the overexpression of let-7a/let-7f in pBABE.pre-let-7a-1.PC-3ML clones (and PCa-20a clones), CFAs, invasive activities in vitro, and tumorigenesis in vivo were significantly reduced. These results show for the first time that RPS2 blocks pre-let-7a-1 processing to enable ras and c-myc expression and the transformation of primary tumor cells.     

Converging forest community composition along an edaphic gradient threatens landscape‐level diversity

Aim Plant communities across the temperate zone are changing in response to successional processes and human‐induced disturbances. Here, we assess how upland forest under‐ and overstorey community composition has changed along an edaphic gradient. Location Northern Wisconsin, USA. Methods Forest sites initially sampled in the 1950s were resampled for overstorey composition and diversity, basal area, and understorey composition and diversity. We used clustering methods to identify groups of stands based on overstorey composition, and we used similarity indices, ordination and diversity indices to evaluate changes in species abundance and overall community structure. Results Sites clustered into four overstorey groups along the edaphic gradient: ‘hemlock’ sites dominated by hemlock in 1950, ‘mesic’ sites dominated by northern hardwoods, ‘dry’ sites with a significant pine inclusion in the canopy and diverse ‘dry‐mesic’ sites in the middle. Collectively, forests gained maple, ash and cherry while losing pines, birches and red oaks. The hemlock forest sites gained hardwoods, while the dry‐mesic sites shifted towards a more mesic hardwood composition. Only the driest sites have remained relatively stable in species composition. Main conclusions These trends reflect both ‘mesification’ and homogenization among northern forests. Highly diverse mid‐gradient and mesic hemlock‐dominated stands are transitioning to maple dominance. Fire suppression may be favouring invasions of more mesic plants into historically drier sites, while high deer abundance likely limits hemlock regeneration. If current trends continue, maples will dominate the majority of northern forests, with significant losses of local native species richness and substantial shifts in understorey composition.     

Species loss of stoneflies (Plecoptera) in the Czech Republic during the 20th century

1. Rapid expansion and intensification of anthropogenic activities in the 20th century has caused profound changes in freshwater assemblages. Unfortunately, knowledge of the extent and causes of species loss (SL) is limited due to the lack of reliable historical data. An unusual data set allows us to compare changes in the most sensitive of aquatic insect orders, the Plecoptera, at some 170 locations in the Czech Republic between two time periods, 1955–1960 and 2006–2010. Historical data (1890–1911) on assemblages of six lowland rivers allow us to infer even earlier changes. 2. Regional stonefly diversity decreased in the first half of the 20th century. Streams at lower altitudes lost a substantial number of species, which were never recovered. In the second half of the century, large‐scale anthropogenic pressure caused SL in all habitats, leading to a dissimilarity of contemporary and previous assemblages. The greatest changes were found at sites affected by organic pollution and a mixture of organic pollution and channelisation or impoundment. Colonisation of new habitats was observed in only three of the 80 species evaluated. 3. Species of moderate habitat specialisation and tolerance to organic pollution were most likely to be lost. Those with narrow specialisations in protected habitats were present in both historical and contemporary collections. 4. Contemporary assemblages are the consequence of more than a 100 years of anthropogenic impacts. In particular, streams at lower altitude and draining intensively exploited landscapes host a mere fragment of the original species complement. Most stonefly species are less frequently present than before, although their assemblages remain almost intact in near‐natural mountain streams. Our analyses demonstrate dramatic restriction of species ranges and, in some cases, apparent changes in altitudinal preference throughout the area.     

Systems analysis of primary Sjögren's syndrome pathogenesis in salivary glands identifies shared pathways in human and a mouse model

Bone tissue has an exceptional quality to regenerate to native tissue in response to injury. However, the fracture repair process requires mechanical stability or a viable biological microenvironment or both to ensure successful healing to native tissue. An improved understanding of the molecular and cellular events that occur during bone repair and remodeling has led to the development of biologic agents that can augment the biological microenvironment and enhance bone repair. Orthobiologics, including stem cells, osteoinductive growth factors, osteoconductive matrices, and anabolic agents, are available clinically for accelerating fracture repair and treatment of compromised bone repair situations like delayed unions and nonunions. Preclinical and clinical studies using biologic agents like recombinant bone morphogenetic proteins have demonstrated an efficacy similar or better than that of autologous bone graft in acute fracture healing. A lack of standardized outcome measures for comparison of biologic agents in clinical fracture repair trials, frequent off-label use, and a limited understanding of the biological activity of these agents at the bone repair site have limited their efficacy in clinical applications.     

Stoichiometry of ferns in Hawaii: implications for nutrient cycling

We asked if element concentrations in ferns differ systematically from those in woody dicots in ways that could influence ecosystem properties and processes. Phylogenetically, ferns are deeply separated from angiosperms; for our analyses we additionally separated leptosporangiate ferns into polypod ferns, a monophyletic clade of ferns which radiated after the rise of angiosperms, and all other leptosporangiate (non-polypod) ferns. We sampled both non-polypod and polypod ferns on a natural fertility gradient and within fertilized and unfertilized plots in Hawaii, and compared our data with shrub and tree samples collected previously in the same plots. Non-polypod ferns in particular had low Ca concentrations under all conditions and less plasticity in their N and P stoichiometry than did polypod ferns or dicots. Polypod ferns were particularly rich in N and P, with low N:P ratios, and their stoichiometry varied substantially in response to differences in nutrient availability. Distinguishing between these two groups has the potential to be useful both in and out of Hawaii, as they have distinct properties which can affect ecosystem function. These differences could contribute to the widespread abundance of polypod ferns in an angiosperm-dominated world, and to patterns of nutrient cycling and limitation in sites where ferns are abundant.