Monomethylarsonous Acid (MMAIII) Has an Adverse Effect on the Innate Immune Response of Human Bronchial Epithelial Cells to Pseudomonas aeruginosa

Arsenic is the number one contaminant of concern with regard to human health according to the World Health Organization. Epidemiological studies on Asian and South American populations have linked arsenic exposure with an increased incidence of lung disease, including pneumonia, and chronic obstructive pulmonary disease, both of which are associated with bacterial infection. However, little is known about the effects of low dose arsenic exposure, or the contributions of organic arsenic to the innate immune response to bacterial infection. This study examined the effects on Pseudomonas aeruginosa (P. aeruginosa) induced cytokine secretion by human bronchial epithelial cells (HBEC) by inorganic sodium arsenite (iAs^III) and two major metabolites, monomethylarsonous acid (MMA^III) and dimethylarsenic acid (DMA^V), at concentrations relevant to the U.S. population. Neither iAs^III nor DMA^V altered P. aeruginosa induced cytokine secretion. By contrast, MMA^III increased P. aeruginosa induced secretion of IL-8, IL-6 and CXCL2. A combination of iAs^III, MMA^III and DMA^V (10 pbb total) reduced IL-8 and CXCL1 secretion. These data demonstrate for the first time that exposure to MMA^III alone, and a combination of iAs^III, MMA^III and DMA^V at levels relevant to the U.S. may have negative effects on the innate immune response of human bronchial epithelial cells to P. aeruginosa.     

In situ seed baiting to isolate germination-enhancing fungi for an epiphytic orchid,Dendrobium aphyllum (Orchidaceae)

Orchid conservation efforts, using seeds and species-specific fungi that support seed germination, require the isolation, identification, and germination enhancement testing of symbiotic fungi. However, few studies have focused on developing such techniques for the epiphytes that constitute the majority of orchids. In this study, conducted in Xishuangbanna Tropical Botanical Garden, Yunnan, China, we used seeds of Dendrobium aphyllum, a locally endangered and medicinally valuable epiphytic orchid, to attract germination promoting fungi. Of the two fungi isolated from seed baiting, Tulasnella spp. and Trichoderma spp., Tulasnella, enhanced seed germination by 13.6 %, protocorm formation by 85.7 %, and seedling development by 45.2 % (all P?Epulorhiza, another seed germination promoting fungi isolated from Cymbidium mannii, also enhanced seed germination (6.5 %; P?P?Trichoderma suppressed seed germination by 26.4 % (P?Tulasnella was the only treatment that produced seedlings. Light increased seed imbibition, protocorm formation, and two-leaved seed development of Tulasnella inoculated seeds (P?Tulasnella be introduced for facilitating D. aphyllum seed germination at the protocorm formation stage and that light be provided for increasing germination as well as further seedling development. Our findings suggest that in situ seed baiting can be used to isolate seed germination-enhancing fungi for the development of seedling production for conservation and reintroduction efforts of epiphytic orchids such as D. aphyllum.     

Decellularized tissue and cell-derived extracellular matrices as scaffolds for orthopaedic tissue engineering

The reconstruction of musculoskeletal defects is a constant challenge for orthopaedic surgeons. Musculoskeletal injuries such as fractures, chondral lesions, infections and tumor debulking can often lead to large tissue voids requiring reconstruction with tissue grafts. Autografts are currently the gold standard in orthopaedic tissue reconstruction; however, there is a limit to the amount of tissue that can be harvested before compromising the donor site. Tissue engineering strategies using allogeneic or xenogeneic decellularized bone, cartilage, skeletal muscle, tendon and ligament have emerged as promising potential alternative treatment. The extracellular matrix provides a natural scaffold for cell attachment, proliferation and differentiation. Decellularization of in vitro cell-derived matrices can also enable the generation of autologous constructs from tissue specific cells or progenitor cells. Although decellularized bone tissue is widely used clinically in orthopaedic applications, the exciting potential of decellularized cartilage, skeletal muscle, tendon and ligament cell-derived matrices has only recently begun to be explored for ultimate translation to the orthopaedic clinic.     

Cerambycid girdling and water stress modify mesquite architecture and reproduction

This study evaluated the effect of an outbreak of the cerambycid beetle, Oncideres rhodosticta, on branch growth and inflorescence production of the mesquite Prosopis glandulosa var. torreyana, and on larvae mortality in girdled branches at two sites (dry and wet) in the southern Chihuahuan Desert of Mexico. We compared stem growth responses to girdling in branches of similar sized trees from both sites over 42 months. The number of larvae per girdled branch was similar between sites, indicating similar ovipositing effort regardless of water stress. However, the proportion of dead larvae was significantly lower in trees at the dry site. On average, girdling reduced 96% of the stem length at both sites. At the end of the first year, 25% of the original stubs survived at the dry site, compared to 90% at the wet site. Girdling also broke apical dominance and allowed for the development of lateral buds from the surviving stubs, which produced many fewer branches and inflorescences at the dry site compared to the wet site, where a compact crown was developed. Water stress and girdling have a combined effect on mesquite architecture and reproduction, since more stubs died at the dry site while new branches from surviving stubs developed at the wet site, recovering the original lost biomass but changing the appearance of the tree.     

Regional Assessment of N Saturation using Foliar and Root \varvec {\delta}^{\bf 15}{\bf N}

N saturation induced by atmospheric N deposition can have serious consequences for forest health in many regions. In order to evaluate whether foliar may be a robust, regional-scale measure of the onset of N saturation in forest ecosystems, we assembled a large dataset on atmospheric N deposition, foliar and root and N concentration, soil C:N, mineralization and nitrification. The dataset included sites in northeastern North America, Colorado, Alaska, southern Chile and Europe. Local drivers of N cycling (net nitrification and mineralization, and forest floor and soil C:N) were more closely coupled with foliar than the regional driver of N deposition. Foliar increased non-linearly with nitrification:mineralization ratio and decreased with forest floor C:N. Foliar was more strongly related to nitrification rates than was foliar N concentration, but concentration was more strongly correlated with N deposition. Root was more tightly coupled to forest floor properties than was foliar . We observed a pattern of decreasing foliar values across the following species: American beech>yellow birch>sugar maple. Other factors that affected foliar included species composition and climate. Relationships between foliar and soil variables were stronger when analyzed on a species by species basis than when many species were lumped. European sites showed distinct patterns of lower foliar , due to the importance of ammonium deposition in this region. Our results suggest that examining values of foliage may improve understanding of how forests respond to the cascading effects of N deposition.     

Context-dependent vocal mimicry in a passerine bird

How do birds select the sounds they mimic, and in what contexts do they use vocal mimicry? Some birds show a preference for mimicking other species' alarm notes, especially in situations when they appear to be alarmed. Yet no study has demonstrated that birds change the call types they mimic with changing contexts. We found that greater racket-tailed drongos (Dicrurus paradiseus) in the rainforest of Sri Lanka mimic the calls of predators and the alarm-associated calls of other species more often than would be expected from the frequency of these sounds in the acoustic environment. Drongos include this alarm-associated mimicry in their own alarm vocalizations, while incorporating other species' songs and contact calls in their own songs. Drongos show an additional level of context specificity by mimicking other species' ground predator-specific call types when mobbing. We suggest that drongos learn other species' calls and their contexts while interacting with these species in mixed flocks. The drongos' behaviour demonstrates that alarm-associated calls can have learned components, and that birds can learn the appropriate usage of calls that encode different types of information.     

Aposematic signal variation predicts male-male interactions in a polymorphic poison frog

Many species use conspicuous "aposematic" signals to communicate unpalatability/unprofitability to potential predators. Although aposematic traits are generally considered to be classic examples of evolution by natural selection, they can also function in the context of sexual selection, and therefore comprise exceptional systems for understanding how conspicuous signals evolve under multifarious selection. We used males from a highly territorial poison frog species in a dichotomous choice behavioral test to conduct the first examination of how aposematic signal variation influences male-male interactions. Our results reveal two behavioral patterns: (1) male dorsal brightness influences the behaviors of male conspecifics such that males approach and call to brighter males more frequently and (2) a male's dorsal brightness predicts his own behavior such that bright males approach stimulus frogs faster, direct more calls to bright stimulus frogs, and exhibit lower advertising call pulse rates (a fitness-related trait). These findings indicate the potential for sexual selection by male-male competition to impact aposematic signal evolution.     

HSD3B and Gene-Gene Interactions in a Pathway-Based Analysis of Genetic Susceptibility to Bladder Cancer

Bladder cancer is the 4^th most common cancer among men in the U.S. We analyzed variant genotypes hypothesized to modify major biological processes involved in bladder carcinogenesis, including hormone regulation, apoptosis, DNA repair, immune surveillance, metabolism, proliferation, and telomere maintenance. Logistic regression was used to assess the relationship between genetic variation affecting these processes and susceptibility in 563 genotyped urothelial cell carcinoma cases and 863 controls enrolled in a case–control study of incident bladder cancer conducted in New Hampshire, U.S. We evaluated gene–gene interactions using Multifactor Dimensionality Reduction (MDR) and Statistical Epistasis Network analysis. The 3′UTR flanking variant form of the hormone regulation gene HSD3B2 was associated with increased bladder cancer risk in the New Hampshire population (adjusted OR 1.85 95%CI 1.31–2.62). This finding was successfully replicated in the Texas Bladder Cancer Study with 957 controls, 497 cases (adjusted OR 3.66 95%CI 1.06–12.63). The effect of this prevalent SNP was stronger among males (OR 2.13 95%CI 1.40–3.25) than females (OR 1.56 95%CI 0.83–2.95), (SNP-gender interaction P = 0.048). We also identified a SNP-SNP interaction between T-cell activation related genes GATA3 and CD81 (interaction P = 0.0003). The fact that bladder cancer incidence is 3–4 times higher in males suggests the involvement of hormone levels. This biologic process-based analysis suggests candidate susceptibility markers and supports the theory that disrupted hormone regulation plays a role in bladder carcinogenesis.     

Species: a praxiographic study

Taxonomists, who describe new species, are acutely aware of how political, economic, and ecological forces bring new forms of life into being. Conducting ethnographic research among taxonomic specialists – experts who bring order to categories of animals, plants, fungi, and microbes – I found that they pay careful attention to the ebb and flow of agency in multispecies worlds. Emergent findings from genomics and information technologies are transforming existing categories and bringing new ones into being. This article argues that the concept of species remains a valuable sense‐making tool despite recent attacks from cultural critics.