scholarly journals Experimental Approaches for the Evaluation of Allelopathic Interactions Between Hermatypic Corals and Marine Benthic Cyanobacteria in the Colombian Caribbean

2019 ◽  
Vol 24 (2) ◽  
pp. 243-254 ◽  
Author(s):  
Mónica Puyana ◽  
Julián Alberto Prato ◽  
Christian Felipe Nieto ◽  
Freddy Alejandro Ramos ◽  
Leonardo Castellanos ◽  
...  
Keyword(s):  
Direct Contact ◽  
Pheophytin A ◽  
Reef Restoration ◽  
Porites Porites ◽  
Benthic Cyanobacteria ◽  
Organic Extracts ◽  
Hermatypic Corals ◽  
Experimental Approaches ◽  
Allelopathic Interactions ◽  
San Andres

Blooms of marine benthic cyanobacteria are recurrent in several locations at the Colombian Caribbean. In these events, cyanobacteria grow over the substrate and benthic organisms although their effect has not been fully assessed. This study evaluated interactions between cyanobacteria and hermatypic corals, in order to identify any deleterious effects that could be related to allelopathic mechanisms. Organic extracts from cyanobacteria collected in San Andres, Old Providence and Rosario islands were tested against embryos of the reef-building coral Orbicella annularis. The indirect effect of cyanobacterial extracts was also assessed by resuspending the extracts in seawater and monitoring polyp retraction and recovery of the coral Madracis mirabilis (=auretenra). Additionally, the effect of direct contact between cyanobacterial extracts and the coral Porites porites was assessed by incorporating cyanobacterial extracts into PhytagelTM gels and placed in direct contact with the coral. After 24, 48 and 72 h of exposure, chromatographic profiles of associated zooxanthellae was evaluated by HPLC. A deleterious effect on the zooxanthellae was evidenced by an increase in pheophytin, a degradation product from chlorophyll. The competitive abilities of algae and cyanobacteria should be considered as a constraint to reef restoration initiatives. Cyanobacteria have the ability to compete with corals due to their growth rates, defenses against herbivory and potentially allelopathic mechanisms.

scholarly journals ECOLOGÍA QUÍMICA DE LAS ESPONJAS EXCAVADORAS CLIONA APRICA, C. CARIBBAEA, C. DELITRIX Y C. TENUIS

2016 ◽  
Vol 34 ◽  
Author(s):  
Andia Chaves Fonnegra ◽  
Mateo López Victoria ◽  
Fernando Parra Velandia ◽  
Sven Zea
Keyword(s):  
Larval Settlement ◽  
Coral Tissue ◽  
Live Coral ◽  
Stegastes Partitus ◽  
Excavating Sponges ◽  
Natural Concentration ◽  
Experimental Media ◽  
Organic Extracts ◽  
Fouling Organisms ◽  
San Andres

The Caribbean encrusting and excavating sponges Cliona aprica, C. caribbaea, C. delitrix and C. tenuis (Porifera, Hadromerida, Clionaidae), aggresively undermine and displace live coral tissue. At San Andrés island and Islas del Rosario (Colombian Caribbean), in all 145 observed cases of direct contact of the sponges C. aprica, C. caribbaea and C. tenuis with 17 coral species, corals showed unhealthy signs in their tissue. It was also noticed that the surface of these sponges is colonized by few organisms and that they are rarely preyed upon. To establish the possible use of chemical substances by these sponges in competition for space with corals (allelopathy), as inhibitors of larval settlement (antifouling), and as feeding deterrents against generalist fish (antipredatory), the activity of crude organic extracts was experimentally evaluated. Extracts were prepared in methanol and 1:2 metanol:dichloromethane and incorporated in experimental media at the natural concentration within the sponges. Using an unpublished method being developed by J. Pawlik (University of North Caroline at Wilmington) and M. Ilan (Tel Aviv University), PhytagelTM disks with crude extracts of each of the four sponge species, placed on the coral Montastrea cavernosa, produced a greater degree of polyp mortality than control gels without extract. Gels with extracts of the sponges C. aprica and C. caribbaea + C. tenuis, served in Petri dishes and used as substratum in the field, inhibited significantly the settlement of fouling organisms, in comparison to control gels. In laboratory trials, wheat flour pellets with extracts C. delitrix and C. caribbaea + C. tenuis were significantly rejected by the omnivore reef damselfish, Stegastes partitus, whereas pellets with extract of C. aprica did not deter feeding. These results suggest that substances present in the crude organic extracts of these sponges may be responsible in part for their ability to compete for reef substrata and to defend themselves from potential aggressors.

scholarly journals Environmental and cultured cyanobacteria as sources of Aedes aegypti larvicides

2019 ◽  
Vol 24 (3) ◽  
pp. 465-496
Author(s):  
Farja I Ayala ◽  
Laura M Becerra ◽  
Jairo Quintana ◽  
Lina M Bayona ◽  
Freddy A Ramos ◽  
...  
Keyword(s):  
Public Health ◽  
Aedes Aegypti ◽  
Bioactive Compounds ◽  
Larvicidal Activity ◽  
Artemia Salina ◽  
Acetylcholinesterase Inhibition ◽  
Effective Control ◽  
Benthic Cyanobacteria ◽  
Organic Extracts ◽  
Chemical Profiles

In tropical countries, the control of the mosquito Aedes aegypti is a public health priority due to its role as a vector of important viral diseases. Marine cyanobacteria are recognized as abundant sources of bioactive compounds, and they constitute a potential source of insecticides useful for controlling mosquito populations and preventing epidemic outbreaks. We collected 30 benthic cyanobacterial mats in Providencia and Rosario islands (in the Colombian Caribbean) belonging to the genera Phormidium, Symploca, Oscillatoria, Lyngbya, Pseudoanabaena, Leptolyngbya, Moorea, and Dapis. Fractions of organic extracts from the most abundant environmental samples were evaluated in three bioassays, assessing (i) larvicidal activity against A. aegypti, (ii) toxicity against the brine shrimp (Artemia salina) nauplii, and (iii) acetylcholinesterase inhibition. Non-polar fractions exhibited larvicidal activity. The polar fraction from one Dapis pleuosa extract showed larvicidal activity without being toxic against A. salina nauplii. Extracts from Moorea producens exhibited the greatest toxicity against A. aegypti larvae and A. salina nauplii. From 23 cultured cyanobacterial samples, only five grew under laboratory conditions and produced enough biomass to yield organic extracts. Of these, three extracts showed strong larvicidal activity, but only the extract from Phormidium tenue showed reduced toxicity against A. salina nauplii. We detected variation among the chemical profiles and larvicidal activity of cyanobacterial consortia depending on sites and dates of collection. Our findings suggest that despite variation in chemical profiles, extracts of marine benthic cyanobacteria can be further developed as effective control agents against insect vectors, in their larval stages. The culture of marine benthic cyanobacteria needs to be further explored to provide enough biomass leading to the identification of bioactive compounds with public health applications.

Saturn's E, G and F rings: modulated by the plasma sheet

1984 ◽  
Vol 75 ◽  
pp. 597
Author(s):  
E. Grün ◽  
G.E. Morfill ◽  
T.V. Johnson ◽  
G.H. Schwehm
Keyword(s):  
Solar Wind ◽  
Direct Contact ◽  
Transport Processes ◽  
Time Variable ◽  
Dust Particles ◽  
Spatial Diffusion ◽  
Drag Forces ◽  
Orbit Perturbation ◽  
Time Variations ◽  
F Ring

ABSTRACTSaturn's broad E ring, the narrow G ring and the structured and apparently time variable F ring(s), contain many micron and sub-micron sized particles, which make up the “visible” component. These rings (or ring systems) are in direct contact with magnetospheric plasma. Fluctuations in the plasma density and/or mean energy, due to magnetospheric and solar wind processes, may induce stochastic charge variations on the dust particles, which in turn lead to an orbit perturbation and spatial diffusion. It is suggested that the extent of the E ring and the braided, kinky structure of certain portions of the F rings as well as possible time variations are a result of plasma induced electromagnetic perturbations and drag forces. The G ring, in this scenario, requires some form of shepherding and should be akin to the F ring in structure. Sputtering of micron-sized dust particles in the E ring by magnetospheric ions yields lifetimes of 102to 104years. This effect as well as the plasma induced transport processes require an active source for the E ring, probably Enceladus.

Learned Placebo Effects in the Immune System

2014 ◽  
Vol 222 (3) ◽  
pp. 148-153 ◽  
Author(s):  
Sabine Vits ◽  
Manfred Schedlowski
Keyword(s):  
Nervous System ◽  
Immune System ◽  
Associative Learning ◽  
Placebo Response ◽  
Immunosuppressive Drug ◽  
Immune Functions ◽  
Placebo Effects ◽  
New Therapeutic Approaches ◽  
Biological Variables ◽  
Experimental Approaches

Associative learning processes are one of the major neuropsychological mechanisms steering the placebo response in different physiological systems and end organ functions. Learned placebo effects on immune functions are based on the bidirectional communication between the central nervous system (CNS) and the peripheral immune system. Based on this “hardware,” experimental evidence in animals and humans showed that humoral and cellular immune functions can be affected by behavioral conditioning processes. We will first highlight and summarize data documenting the variety of experimental approaches conditioning protocols employed, affecting different immunological functions by associative learning. Taking a well-established paradigm employing a conditioned taste aversion model in rats with the immunosuppressive drug cyclosporine A (CsA) as an unconditioned stimulus (US) as an example, we will then summarize the efferent and afferent communication pathways as well as central processes activated during a learned immunosuppression. In addition, the potential clinical relevance of learned placebo effects on the outcome of immune-related diseases has been demonstrated in a number of different clinical conditions in rodents. More importantly, the learned immunosuppression is not restricted to experimental animals but can be also induced in humans. These data so far show that (i) behavioral conditioned immunosuppression is not limited to a single event but can be reproduced over time, (ii) immunosuppression cannot be induced by mere expectation, (iii) psychological and biological variables can be identified as predictors for this learned immunosuppression. Together with experimental approaches employing a placebo-controlled dose reduction these data provide a basis for new therapeutic approaches to the treatment of diseases where a suppression of immune functions is required via modulation of nervous system-immune system communication by learned placebo effects.

Worker Protection Standard: Owner and Immediate Family Exemption

EDIS ◽  
2016 ◽  
Vol 2016 (7) ◽  
Author(s):  
Frederick M. Fishel ◽  
Tatiana Sanchez
Keyword(s):  
Direct Contact ◽  
Family Members ◽  
Agricultural Workers ◽  
Federal Regulation ◽  
Fact Sheet ◽  
Agricultural Plants

The Worker Protection Standard (WPS) is a Federal regulation designed to protect agricultural workers (people involved in the production of agricultural plants) and pesticide handlers (people mixing, loading, or applying pesticides or doing other tasks involving direct contact with pesticides).There are certain exemptions in the WPS rule that have been revised pertaining to agricultural establishment owners and their immediate family members. This fact sheet explains these new provisions.

Worker Protection Standard: Information at a Central Location

EDIS ◽  
2016 ◽  
Vol 2016 (7) ◽  
Author(s):  
Frederick M. Fishel ◽  
Tatiana Sanchez
Keyword(s):  
Direct Contact ◽  
Agricultural Workers ◽  
Specific Information ◽  
Federal Regulation ◽  
Central Location ◽  
Agricultural Pesticides ◽  
Full Implementation ◽  
Standard Information ◽  
Agricultural Plants ◽  
General Guidance

The Worker Protection Standard (WPS) is a Federal regulation designed to protect agricultural workers (people involved in the production of agricultural plants) and pesticide handlers (people mixing, loading, or applying pesticides or doing other tasks involving direct contact with pesticides). It has been in full implementation since 1995. This document provides general guidance to help you comply with the requirements of the Federal Worker Protection Standard (WPS) for agricultural pesticides, 40 CFR part 170, as amended in 2015. This document addresses specific information that agricultural establishments must display at a central location for their employees.

Managing total reduced sulfur emissions at a Canadian kraft pulp mill

TAPPI Journal ◽  
2016 ◽  
Vol 15 (4) ◽  
pp. 265-272 ◽  
Author(s):  
ROHAN BANDEKAR ◽  
JIM FREDERICK ◽  
JAROSLAV STAVIK
Keyword(s):  
Direct Contact ◽  
Black Liquor ◽  
Pulp Mill ◽  
Packed Bed ◽  
Average Value ◽  
Emission Limit ◽  
Total Reduced Sulfur ◽  
Reduced Sulfur ◽  
Air Ingress ◽  
Solids Content

This study addresses the challenges a dissolving-grade pulp mill in Canada faced in 2014 in meeting its total reduced sulfur (TRS) gas emission limit. These emissions from the recovery boiler exit are controlled by passing the boiler exit gas through a TRS scrubber system. The mill employs a cyclonic direct contact evaporator to concentrate black liquor to firing solids content. The off-gases from the direct contact evaporator flow to the effluent gas control system that consists of a venturi scrubber, a packed bed scrubber, and a heat recovery unit. Emissions of TRS greater than the regulated limit of 15 ppm were observed for a 4-month period in 2014. The level of emissions measured during this period was significantly higher than about 12 ppm, the expected average value based on historic experience. The problem persisted from mid-June 2014 until the annual mill shutdown in October 2014. The main TRS components detected and the performance of the Teller scrubber in capturing them are examined. Other potential causes for these emissions are identified, including mechanical problems such as broken packing in the TRS packed bed scrubber, broken baffle plates in the scrubber, and cyclone evaporator leaks causing air ingress. Repairs were carried out during the mill shutdown, which eliminated the TRS emissions problem.

Coral husbandry for ocean futures: leveraging abiotic factors to increase survivorship, growth, and resilience in juvenile Montipora capitata

2021 ◽  
Vol 657 ◽  
pp. 123-133
Author(s):  
JR Hancock ◽  
AR Barrows ◽  
TC Roome ◽  
AS Huffmyer ◽  
SB Matsuda ◽  
...  
Keyword(s):  
Abiotic Factors ◽  
Larval Rearing ◽  
Abiotic Conditions ◽  
Montipora Capitata ◽  
Reef Restoration ◽  
Juvenile Corals ◽  
Bleaching Response ◽  
The Face ◽  
Survival And Growth ◽  
Global And Local

Reef restoration via direct outplanting of sexually propagated juvenile corals is a key strategy in preserving coral reef ecosystem function in the face of global and local stressors (e.g. ocean warming). To advance our capacity to scale and maximize the efficiency of restoration initiatives, we examined how abiotic conditions (i.e. larval rearing temperature, substrate condition, light intensity, and flow rate) interact to enhance post-settlement survival and growth of sexually propagated juvenile Montipora capitata. Larvae were reared at 3 temperatures (high: 28.9°C, ambient: 27.2°C, low: 24.5°C) for 72 h during larval development, and were subsequently settled on aragonite plugs conditioned in seawater (1 or 10 wk) and raised in different light and flow regimes. These juvenile corals underwent a natural bleaching event in Kāne‘ohe Bay, O‘ahu, Hawai‘i (USA), in summer 2019, allowing us to opportunistically measure bleaching response in addition to survivorship and growth. This study demonstrates how leveraging light and flow can increase the survivorship and growth of juvenile M. capitata. In contrast, larval preconditioning and substrate conditioning had little overall effect on survivorship, growth, or bleaching response. Importantly, there was no optimal combination of abiotic conditions that maximized survival and growth in addition to bleaching tolerances. This study highlights the ability to tailor sexual reproduction for specific restoration goals by addressing knowledge gaps and incorporating practices that could improve resilience in propagated stocks.

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