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https://www.readbyqxmd.com/read/28081446/host-to-host-transmission-of-streptococcus-pneumoniae-is-driven-by-its-inflammatory-toxin-pneumolysin
#1
M Ammar Zafar, Yang Wang, Shigeto Hamaguchi, Jeffrey N Weiser
Host-to-host transmission is a critical step for infection. Here we studied transmission of the opportunistic pathogen Streptococcus pneumoniae in an infant mouse model. Transmission from nasally colonized pups required high levels of bacterial shedding in nasal secretions and was temporally correlated with, and dependent upon, the acute inflammatory response. Pneumolysin, a pore-forming cytotoxin and major virulence determinant, was both necessary and sufficient to promote inflammation, which increased shedding and allowed for intralitter transmission...
January 11, 2017: Cell Host & Microbe
https://www.readbyqxmd.com/read/28073542/the-rise-of-toxic-benthic-phormidium-proliferations-a-review-of-their-taxonomy-distribution-toxin-content-and-factors-regulating-prevalence-and-increased-severity
#2
REVIEW
Tara G McAllister, Susanna A Wood, Ian Hawes
There has been a marked increase in the distribution, intensity and frequency of proliferations of some species of the benthic mat-forming, toxin-producing genus Phormidium in rivers globally over the last decade. This review summarises current knowledge on their taxonomy, distribution, toxin content, environmental drivers of proliferations, and monitoring and management strategies in New Zealand. Although toxic Phormidium proliferation occurs in rivers worldwide little is known about these factors in most countries...
May 2016: Harmful Algae
https://www.readbyqxmd.com/read/28073540/phylogenetic-structure-of-bacterial-assemblages-co-occurring-with-ostreopsis-cf-ovata-bloom
#3
Silvana Vanucci, Flavio Guidi, Rossella Pistocchi, Richard A Long
Extensive blooms of the toxic epiphytic/benthic dinoflagellate Ostreopsis cf. ovata are being reported with increasing frequency and spatial distribution in temperate coastal regions including the Mediterranean. These blooms are of human and environmental health concern due to the production of isobaric palytoxin and a wide range of ovatoxins by Ostreopsis cf. ovata. Bacterial-microalgal interactions are important regulators in algal bloom dynamics and potentially toxin dynamics. This study investigated the bacterial assemblages co-occurring with O...
May 2016: Harmful Algae
https://www.readbyqxmd.com/read/28073538/margalef-revisited-a-new-phytoplankton-mandala-incorporating-twelve-dimensions-including-nutritional-physiology
#4
Patricia M Glibert
Building on the classic depiction of the progression from a diatom to a dinoflagellate bloom as a function of nutrients and turbulence, known as the "Margalef mandala", a new conceptual model or mandala is presented here. The new mandala maps twelve response or effects traits, or environmental characteristics, related to different phytoplankton functional types: (1) relative preference for chemically reduced vs chemically oxidized forms of nitrogen; (2) relative availability of inorganic nitrogen and phosphorus; (3) adaptation to high vs low light and the tendency to be autotrophic vs mixotrophic; (4) cell motility; (5) environmental turbulence; (6) pigmentation quality; (7) temperature; (8) cell size; (9) relative growth rate; (10) relative production of bioactive compounds such as toxins or reactive oxygen species (ROS); (11) r vs K strategy; and (12) fate of the production in terms of grazing...
May 2016: Harmful Algae
https://www.readbyqxmd.com/read/28073533/effects-of-n-and-p-availability-on-carbon-allocation-in-the-toxic-dinoflagellate-ostreopsis-cf-ovata
#5
Laura Pezzolesi, Silvana Vanucci, Carmela Dell'Aversano, Emma Dello Iacovo, Luciana Tartaglione, Rossella Pistocchi
Blooms of the toxic dinoflagellate Ostreopsis cf. ovata are usually associated with shallow and calm coastal waters, characterized by low nutrient concentrations. The algal cells typically cover the benthic substrates, such as the macroalgal and invertebrate communities and rocks, forming a mucilaginous film. Data reported on O. cf. ovata toxin production observed under both field and culture conditions show high variability in terms of toxic profile and cellular content; little is known about the environmental and physiological aspects which regulate the toxin dynamics...
May 2016: Harmful Algae
https://www.readbyqxmd.com/read/28073529/seasonality-and-toxin-production-of-pyrodinium-bahamense-in-a-red-sea-lagoon
#6
E Banguera-Hinestroza, W Eikrem, H Mansour, I Solberg, J Cúrdia, K Holtermann, B Edvardsen, S Kaartvedt
Harmful algal blooms of the dinoflagellate Pyrodinium bahamense have caused human and economic losses in the last decades. This study, for the first time, documents a bloom of P. bahamense in the Red Sea. The alga was recurrently present in a semi-enclosed lagoon throughout nearly 2 years of observations. The highest cell densities (10(4)-10(5)cellsL(-1)) were recorded from September to beginning of December at temperatures and salinities of ∼26-32°C and ∼41, respectively. The peak of the bloom was recorded mid-November, before a sharp decrease in cell numbers at the end of December...
May 2016: Harmful Algae
https://www.readbyqxmd.com/read/28073525/delineation-of-the-role-of-nutrient-variability-and-dreissenids-mollusca-bivalvia-on-phytoplankton-dynamics-in-the-bay-of-quinte-ontario-canada
#7
Yuko Shimoda, Sue B Watson, Michelle E Palmer, Marten A Koops, Shan Mugalingam, Andrew Morley, George B Arhonditsis
The Bay of Quinte, a Z-shaped embayment at the northeastern end of Lake Ontario, has a long history of eutrophication problems primarily manifested as spatially extensive algal blooms and predominance of toxic cyanobacteria. The purpose of this study was to identify the structural changes of the phytoplankton community induced by two environmental alterations: point-source phosphorus (P) loading reduction in the late 1970s and establishment of dreissenid mussels in the mid-1990s. A combination of statistical techniques was used to draw inference about compositional shifts of the phytoplankton assemblage, the consistency of the seasonal succession patterns along with the mechanisms underlying the algal biovolume variability in the Bay of Quinte over the past three decades...
May 2016: Harmful Algae
https://www.readbyqxmd.com/read/28073493/abiotic-variables-affect-stx-concentration-in-a-meso-oligotrophic-subtropical-coastal-lake-dominated-by-cylindrospermopsis-raciborskii-cyanophyceae
#8
Débora Monteiro Brentano, Eduardo L Hettwer Giehl, Maurício Mello Petrucio
The cyanobacterium Cylindrospermopsis raciborskii is capable of producing toxins including saxitoxin (STX). Few studies have verified the influence of environmental variables on the production of STX and most have only been studied in the laboratory. The goal of this work was to identify the abiotic variables related to STX concentration in situ. The relationship among STX concentration and the physical variables, nutrients and chlorophyll-a (chl-a) concentration was examined in a meso-oligotrophic subtropical coastal lake dominated by C...
June 2016: Harmful Algae
https://www.readbyqxmd.com/read/28073482/an-overview-of-diversity-occurrence-genetics-and-toxin-production-of-bloom-forming-dolichospermum-anabaena-species
#9
REVIEW
Xiaochuang Li, Theo W Dreher, Renhui Li
The new genus name Dolichospermum, for most of the planktonic former members of the genus Anabaena, is one of the most ubiquitous bloom-forming cyanobacterial genera. Its dominance and persistence have increased in recent years, due to eutrophication from anthropogenic activities and global climate change. Blooms of Dolichospermum species, with their production of secondary metabolites that commonly include toxins, present a worldwide threat to environmental and public health. In this review, recent advances of the genus Dolichospermum are summarized, including taxonomy, genetics, bloom occurrence, and production of toxin and taste-and-odor compounds...
April 2016: Harmful Algae
https://www.readbyqxmd.com/read/28073481/understanding-the-winning-strategies-used-by-the-bloom-forming-cyanobacterium-cylindrospermopsis-raciborskii
#10
REVIEW
Michele A Burford, John Beardall, Anusuya Willis, Philip T Orr, Valeria F Magalhaes, Luciana M Rangel, Sandra M F O E Azevedo, Brett A Neilan
The cyanobacterium Cylindrospermopsis raciborskii is a widespread species increasingly being recorded in freshwater systems around the world. It is of particular concern because strains in some geographic areas are capable of producing toxins with implications for human and animal health. Studies of this species have increased rapidly in the last two decades, especially in the southern hemisphere where toxic strains are prevalent. A clearer picture is emerging of the strategies adopted by this species to bloom and out-compete other species...
April 2016: Harmful Algae
https://www.readbyqxmd.com/read/28073467/quantitative-pcr-assay-for-detection-and-enumeration-of-ciguatera-causing-dinoflagellate-gambierdiscus-spp-gonyaulacales-in-coastal-areas-of-japan
#11
Tomohiro Nishimura, Naohito Hariganeya, Wittaya Tawong, Hiroshi Sakanari, Haruo Yamaguchi, Masao Adachi
In Japan, ciguatera fish poisoning (CFP) has been increasingly reported not only in subtropical areas but also in temperate areas in recent years, causing a serious threat to human health. Ciguatera fish poisoning is caused by the consumption of fish that have accumulated toxins produced by an epiphytic/benthic dinoflagellate, genus Gambierdiscus. Previous studies revealed the existence of five Gambierdiscus species/phylotypes in Japan: Gambierdiscus australes, Gambierdiscus scabrosus, Gambierdiscus sp. type 2, Gambierdiscus sp...
February 2016: Harmful Algae
https://www.readbyqxmd.com/read/28073455/estimating-microcystin-levels-at-recreational-sites-in-western-lake-erie-and-ohio
#12
Donna S Francy, Amie M G Brady, Christopher D Ecker, Jennifer L Graham, Erin A Stelzer, Pamela Struffolino, Daryl F Dwyer, Keith A Loftin
Cyanobacterial harmful algal blooms (cyanoHABs) and associated toxins, such as microcystin, are a major global water-quality issue. Water-resource managers need tools to quickly predict when and where toxin-producing cyanoHABs will occur. This could be done by using site-specific models that estimate the potential for elevated toxin concentrations that cause public health concerns. With this study, samples were collected at three Ohio lakes to identify environmental and water-quality factors to develop linear-regression models to estimate microcystin levels...
September 2016: Harmful Algae
https://www.readbyqxmd.com/read/28073440/climate-variability-and-dinophysis-acuta-blooms-in-an-upwelling-system
#13
Patricio A Díaz, Manuel Ruiz-Villarreal, Yolanda Pazos, Teresa Moita, Beatriz Reguera
Dinophysis acuta is a frequent seasonal lipophilic toxin producer in European Atlantic coastal waters associated with thermal stratification. In the Galician Rías, populations of D. acuta with their epicentre located off Aveiro (northern Portugal), typically co-occur with and follow those of Dinophysis acuminata during the upwelling transition (early autumn) as a result of longshore transport. During hotter than average summers, D. acuta blooms also occur in August in the Rías, when they replace D. acuminata...
March 2016: Harmful Algae
https://www.readbyqxmd.com/read/28071525/additive-toxic-effect-of-deltamethrin-and-cadmium-on-hepatic-hematological-and-immunological-parameters-in-mice
#14
Hasibur Rehman, Al Thbiani Aziz, Shalini Saggu, Adam L VanWert, Nahla Zidan, Sundeep Saggu
Exposure to natural and man-made environmental toxins concurrently can pose a greater threat to multiple organs. In the present work, we investigated interactions between deltamethrin (DM) and cadmium (Cd), whose mechanisms of action in humans are poorly understood. Albino mice were randomly divided into four groups, each containing six mice: saline as control, DM-treated, cadmium chloride (CdCl2)-treated, and CdCl2 plus DM treated. After 2 weeks of treatment biochemical and hematological effects, total leukocyte count (TLC), differential leukocyte count, humoral-mediated immune responses, and histopathological studies were conducted...
January 1, 2017: Toxicology and Industrial Health
https://www.readbyqxmd.com/read/28055293/epidermal-activation-of-the-small-gtpase-rac1-in-psoriasis-pathogenesis
#15
Mårten C G Winge, M Peter Marinkovich
The small GTPase Ras-related C3 botulinum toxin substrate 1 (RAC1) plays a central role in skin homeostasis, including barrier function, wound healing and inflammatory responses. Psoriasis is a common skin disease characterized by deregulation of these functions, and affected skin exhibit keratinocyte hyperproliferation, inflammation and immune cell infiltration. Although psoriasis is often triggered by environmental stimulus, there is a strong genetic association with genes expressed in both immune cells and keratinocytes, of which several are linked to Rac1 signaling...
January 5, 2017: Small GTPases
https://www.readbyqxmd.com/read/28052646/ameliorative-potentials-of-quercetin-against-lead-induced-hematological-and-testicular-alterations-in-albino-rats
#16
Mohammed A. Al-Omair, Azza Sedky, Awatef Ali, Hany Elsawy
Lead is one of the oldest environmental and occupational toxins. Health hazards from increased lead exposure as a result of industrial and environmental pollution are recognized. The aim of the present study was to investigate the protective effects of quercetin as a model of an antioxidant drug against the toxic effects of lead acetate on the blood and the testis of rats. The lead concentrations were determined in blood and the testis. Testosterone (T), luteinizing hormone (LH) and follicle stimulating hormone (FSH) were assessed in serum...
28, 2017: Chinese Journal of Physiology
https://www.readbyqxmd.com/read/28050732/nutrient-supply-and-simulated-herbivory-differentially-alter-the-metabolite-pools-and-the-efficacy-of-the-glucosinolate-based-defense-system-in-brassica-species
#17
Makhdora Almuziny, Charlotte Decker, Dong Wang, Patrick Gerard, Nishanth Tharayil
Environmental stress hinders growth of plants and commonly results in the accumulation of carbon-based defense compounds. However, the dynamics of nitrogen (N)-containing defense compounds are less predictable under environmental stress. The impact of nutrient deficiency on plant defenses that require the metabolic conversion of a less toxic compound to a more potent toxin is even more poorly understood. We evaluated the effects of nitrogen (N) and potassium (K) deficiency and simulated herbivory on the concentration of metabolites including glucosinolates (GSLs), on the conversion of GSLs to more toxic isothiocyanates (ITCs), and on the activity of myrosinase (MYR) in leaves of Brassica juncea and Brassica nigra...
January 3, 2017: Journal of Chemical Ecology
https://www.readbyqxmd.com/read/28050633/biopolymer-microencapsulations-of-bacillus-thuringiensis-crystal-preparations-for-increased-stability-and-resistance-to-environmental-stress
#18
Xiaolin He, Zhongqin Sun, Kanglai He, Shuyuan Guo
Parasporal crystals synthesized by Bacillus thuringiensis (Bt) have been widely used as microbial pesticides because of their toxicity to the larval stages of specific insects. However, parasporal crystals can be damaged by environmental stresses, such as high temperature, ultraviolet radiation, and desiccation. To reduce environmental susceptibility of parasporal crystals and extend the duration of their activity, we developed a new type of protection by making microcapsules of crystals (MCs). The microcapsules were self-assembled by alternate deposition (layer by layer) of low-cost chitosan and sodium alginate (or sodium carboxymethyl cellulose) on the crystal surface...
January 3, 2017: Applied Microbiology and Biotechnology
https://www.readbyqxmd.com/read/28045087/nutrition-affects-insect-susceptibility-to-bt-toxins
#19
Carrie A Deans, Spencer T Behmer, Ashley E Tessnow, Patricia Tamez-Guerra, Marianne Pusztai-Carey, Gregory A Sword
Pesticide resistance represents a major challenge to global food production. The spread of resistance alleles is the primary explanation for observations of reduced pesticide efficacy over time, but the potential for gene-by-environment interactions (plasticity) to mediate susceptibility has largely been overlooked. Here we show that nutrition is an environmental factor that affects susceptibility to Bt toxins. Protein and carbohydrates are two key macronutrients for insect herbivores, and the polyphagous pest Helicoverpa zea self-selects and performs best on diets that are protein-biased relative to carbohydrates...
January 3, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28043017/evolution-and-structural-dynamics-of-bacterial-glycan-binding-adhesins
#20
REVIEW
Kristof Moonens, Han Remaut
Infectious disease processes like bacterial adherence or the activity of secreted toxins frequently gain host and tissue specificity by glycan binding interactions with the host glycome. Recent functional and structural studies highlight the high niche specialization of bacterial lectins, but also reveal a remarkable plasticity in their glycan binding sites and mechanisms, to adapt to host glycome dynamics or changing environmental conditions at the site of infection. In this review we put emphasis on new structural insights in host adaptation and dynamics of bacterial carbohydrate binding adhesins and toxins in human pathogens like uropathogenic and enteropathogenic Escherichia coli, Helicobacter pylori, Yersinia pestis or Vibrio cholera...
December 30, 2016: Current Opinion in Structural Biology
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