Harnessing Pseudomonas protegens to Control Bacterial Panicle Blight of Rice.

Bacterial panicle blight of rice is a seedborne disease caused by the bacterium Burkholderia glumae. This disease has affected rice production worldwide and its effects are likely to become more devastating with the continuous increase in global temperatures, especially during the growing season. The bacterium can cause disease symptoms in different tissues and at different developmental stages. In reproductive stages, the bacterium interferes with grain development in the panicles and, as a result, directly affects rice yield. Currently, there are no methods to control the disease because chemical control is not effective and completely resistant cultivars are not available. Thus, a promising approach is the use of antagonistic microorganisms. In this work, we identified one strain of Pseudomonas protegens and one strain of B. cepacia with antimicrobial activity against B. glumae in vitro and in planta. We further characterized the antimicrobial activity of P. protegens and found that this activity is associated with bacterial secretions. Cell-free secretions from P. protegens inhibited the growth of B. glumae in vitro and also prevented B. glumae from causing disease in rice. Although the specific molecules associated with these activities have not been identified, these findings suggest that the secreted fractions from P. protegens could be harnessed as biopesticides to control bacterial panicle blight of rice.

Microglial responses to inflammatory challenge in adult rats altered by developmental exposure to polychlorinated biphenyls in a sex-specific manner.

Polychlorinated biphenyls are ubiquitous environmental contaminants linkedc with peripheral immune and neural dysfunction. Neuroimmune signaling is critical to brain development and later health; however, effects of PCBs on neuroimmune processes are largely undescribed. This study extends our previous work in neonatal or adolescent rats by investigating longer-term effects of perinatal PCB exposure on later neuroimmune responses to an inflammatory challenge in adulthood. Male and female Sprague-Dawley rats were exposed to a low-dose, environmentally relevant, mixture of PCBs (Aroclors 1242, 1248, and 1254, 1:1:1, 20 µg / kg dam BW per gestational day) or oil control during gestation and via lactation. Upon reaching adulthood, rats were given a mild inflammatory challenge with lipopolysaccharide (LPS, 50 µg / kg BW, ip) or saline control and then euthanized 3 hours later for gene expression analysis or 24 hours later for immunohistochemical labeling of Iba1+ microglia. PCB exposure did not alter gene expression or microglial morphology independently, but instead interacted with the LPS challenge in brain region- and sex-specific ways. In the female hypothalamus, PCB exposure blunted LPS responses of neuroimmune and neuromodulatory genes without changing microglial morphology. In the female prefrontal cortex, PCBs shifted Iba1+ cells from reactive to hyperramified morphology in response to LPS. Conversely, in the male hypothalamus, PCBs shifted cell phenotypes from hyperramified to reactive morphologies in response to LPS. The results highlight the potential for long-lasting effects of environmental contaminants that are differentially revealed over a lifetime, sometimes only after a secondary challenge. These neuroimmune endpoints are possible mechanisms for PCB effects on a range of neural dysfunction in adulthood, including mental health and neurodegenerative disorders. The findings suggest possible interactions with other environmental challenges that also influence neuroimmune systems.

The PIKK-AKT connection in the DNA damage response.

DNA damage and subsequent cellular response are the basis for many cancer treatments. In this issue of Science Signaling, Liu et al. elucidate a mechanism by which cancer cells survive DNA damage induced by radiation and chemotherapy.

Sex-specific effects of developmental exposure to polychlorinated biphenyls on neuroimmune and dopaminergic endpoints in adolescent rats.

Exposure to environmental contaminants early in life can have long lasting consequences for physiological function. Polychlorinated biphenyls (PCBs) are a group of ubiquitous contaminants that perturb endocrine signaling and have been associated with altered immune function in children. In this study, we examined the effects of developmental exposure to PCBs on neuroimmune responses to an inflammatory challenge during adolescence. Sprague Dawley rat dams were exposed to a PCB mixture (Aroclor 1242, 1248, 1254, 1:1:1, 20 µg/kg/day) or oil control throughout pregnancy, and adolescent male and female offspring were injected with lipopolysaccharide (LPS, 50 µg/kg, ip) or saline control prior to euthanasia. Gene expression profiling was conducted in the hypothalamus, prefrontal cortex, striatum, and midbrain. In the hypothalamus, PCBs increased expression of genes involved in neuroimmune function, including those within the nuclear factor kappa b (NF-κB) complex, independent of LPS challenge. PCB exposure also increased expression of receptors for dopamine, serotonin, and estrogen in this region. In contrast, in the prefrontal cortex, PCB exposure blunted or induced irregular neuroimmune gene expression responses to LPS challenge. Moreover, neither PCB nor LPS exposure altered expression of neurotransmitter receptors throughout the mesocorticolimbic circuit. Almost all effects were present in males but not females, in agreement with the idea that male neuroimmune cells are more sensitive to perturbation and emphasizing the importance of studying both male and female subjects. Given that altered neuroimmune signaling has been implicated in mental health and substance abuse disorders that often begin during adolescence, these results highlight neuroimmune processes as another mechanism by which early life PCBs can alter brain function later in life.

Identification of metabolites produced during the complete biodegradation of 1-butyl-3-methylimidazolium chloride by an enriched activated sludge microbial community.

Ionic liquids (ILs) are highly polar solvents with unique physicochemical properties that make them promising green alternatives to volatile organic solvents. Since ILs can be toxic to organisms, the development of methods to degrade ILs into harmless molecules prior to disposal is critical to enhancing their green properties. In this study, metabolites generated during the biodegradation of 1-butyl-3-methylimidazolium chloride (BMIMCl) by an enriched, activated sludge microbial community were investigated. Biodegradation of BMIM and the metabolic products released into the growth media were examined using 1H-NMR spectroscopy and mass spectrometry. To the best of our knowledge, this is the first reported complete primary catabolism of the biodegradation-resistant BMIMCl ionic liquid. The bacterial community responsible for degradation was analyzed using a 16S-rRNA amplicon approach. Although the community was diverse, Bacteroidetes was the predominant phylum. The study provides a greater insight into imidazolium-based IL biodegradability and a means to proactively prevent the ecotoxicity of the BMIM cation and its metabolites, by complete primary biodegradation of the cation and removal of most resulting metabolites, prior to release into aquatic waste streams.

Pain and Surgery in England, circa 1620-circa 1740.

The scholarship on the discussion and role of pain in early modern English surgery is limited. Scholars have given little consideration to how surgeons described and comprehended pain in their patients' bodies in early modern England, including how these understandings connected to notions of the humours, nerves and sex difference. This article focuses on the attention that surgeons paid to pain in their published and manuscript casebooks and manuals available in English, circa 1620-circa 1740. Pain was an important component of surgery in early modern England, influencing diagnosis, treatment and technique. Surgeons portrayed a complex and multi-dimensional understanding of their patients' bodies in pain, which was further connected to their portrayals of their professional ability.

Ionic liquid biodegradability depends on specific wastewater microbial consortia.

Complete biodegradation of a newly-synthesized chemical in a wastewater treatment plant (WWTP) eliminates the potential for novel environmental pollutants. However, differences within- and between-WWTP microbial communities may alter expectations for biodegradation. WWTP communities can also serve as a source of unique consortia that, when enriched, can metabolize chemicals that tend to resist degradation, but are otherwise promising green alternatives. We tested the biodegradability of three ionic liquids (ILs): 1-octyl-3-methylpyridinium bromide (OMP), 1-butyl-3-methylpyridinium bromide (BMP) and 1-butyl-3-methylimidazolium chloride (BMIM). We performed tests using communities from two WWTPs at three time points. Site-specific and temporal variation both influenced community composition, which impacted the success of OMP biodegradability. Neither BMP nor BMIM degraded in any test, suggesting that these ILs are unlikely to be removed by traditional treatment. Following standard biodegradation assays, we enriched for three consortia that were capable of quickly degrading OMP, BMP and BMIM. Our results indicate WWTPs are not functionally redundant with regard to biodegradation of specific ionic liquids. However, consortia can be enriched to degrade chemicals that fail biodegradability assays. This information can be used to prepare pre-treatment procedures and prevent environmental release of novel pollutants.

Size-dependent antimicrobial effects of novel palladium nanoparticles.

Investigating the interactions between nanoscale materials and microorganisms is crucial to provide a comprehensive, proactive understanding of nanomaterial toxicity and explore the potential for novel applications. It is well known that nanomaterial behavior is governed by the size and composition of the particles, though the effects of small differences in size toward biological cells have not been well investigated. Palladium nanoparticles (Pd NPs) have gained significant interest as catalysts for important carbon-carbon and carbon-heteroatom reactions and are increasingly used in the chemical industry, however, few other applications of Pd NPs have been investigated. In the present study, we examined the antimicrobial capacity of Pd NPs, which provides both an indication of their usefulness as target antimicrobial compounds, as well as their potency as potential environmental pollutants. We synthesized Pd NPs of three different well-constrained sizes, 2.0 ± 0.1 nm, 2.5 ± 0.2 nm and 3.1 ± 0.2 nm. We examined the inhibitory effects of the Pd NPs and Pd(2+) ions toward gram negative Escherichia coli (E. coli) and gram positive Staphylococcus aureus (S. aureus) bacterial cultures throughout a 24 hour period. Inhibitory growth effects of six concentrations of Pd NPs and Pd(2+) ions (2.5 × 10(-4), 10(-5), 10(-6), 10(-7), 10(-8), and 10(-9) M) were examined. Our results indicate that Pd NPs are generally much more inhibitory toward S. aureus than toward E. coli, though all sizes are toxic at ≥ 10(-5) M to both organisms. We observed a significant difference in size-dependence of antimicrobial activity, which differed based on the microorganism tested. Our work shows that Pd NPs are highly antimicrobial, and that fine-scale (<1 nm) differences in size can alter antimicrobial activity.

Family functioning and coping styles in families of children with cancer and HIV disease.

Disease-specific characteristics of pediatric illnesses may influence the functioning of families and the coping responses they enact. This study compared family functioning and coping styles within and between 2 different medical groups: families of children with cancer (n = 44) and HIV disease (n = 65). Most caregivers reported healthy family functioning, and no between-group differences in functioning emerged. However, with regard to coping, more reliance on social support was indicated among the cancer group. Also, the HIV group largely sought support from family, whereas both family and nonfamily support were sought among the cancer group. Better functioning was related to reframing, an active coping style, within the cancer group and passive coping within the HIV group. Thus, coping strategies and their implications for family functioning vary by condition. Researchers should avoid combining various illness groups indiscriminately. Likewise, clinicians should be sensitive to disease-specific factors when helping families learn to cope with illness-related stressors.