Pathogenicity and host specificity of Labyrinthuloides haliotidis (Protozoa: Labyrinthomorpha), a parasite of juvenile abalone

1987 ◽  
Vol 65 (8) ◽  
pp. 2008-2012 ◽  
Author(s):  
Susan M. Bower
Keyword(s):  
Shell Length ◽  
Laboratory Experiments ◽  
Sea Water ◽  
Oyster Tissue ◽  
Shell Size ◽  
Patinopecten Yessoensis ◽  
Haliotis Rufescens ◽  
Small Juvenile ◽  
Almost All ◽  
Gain Access

Infections with Labyrinthuloides haliotidis, an achlorophyllous, eucaryotic protist, were lethal to almost all juvenile abalone (Haliotis kamtschatkana and Haliotis rufescens) less than 6 months of age in an abalone mariculture facility in British Columbia, Canada. In laboratory experiments, L. haliotidis isolated from infected abalone or grown in axenic nutrient medium was infective for abalone (H. kamtschatkana) less than 4.0 mm in shell length and 140 days of age. Ten days after exposure to at least 104 parasites in 20 mL of sea water, about 90% of these abalone died with numerous parasites throughout the tissues of the head and foot. By about 190 days of age, regardless of shell size, abalone mortalities were reduced to less than 50% after exposure to about 105 parasites. Finally, by about 340 days of age, most juvenile abalone (4.0 to 10.5 mm in shell length) did not succumb after three consecutive exposures, 13 days apart, to between 2 × 105 and 5 × 106L. haliotidis. Larger abalone (15 to 25 mm in shell length) did not become infected following intramuscular injections of about 1.5 × 104L. haliotidis. Small juvenile scallops (Patinopecten yessoensis) and juvenile oysters (Crassostrea gigas), both less than 8 months of age, were also resistant to infection. However, two of the oysters with badly cracked shells became infected. This suggests that if L. haliotidis can gain access, it is capable of using living oyster tissue as a source of nutrients for growth and multiplication.

Labyrinthuloides haliotidis n.sp. (Protozoa: Labyrinthomorpha), a pathogenic parasite of small juvenile abalone in a British Columbia mariculture facility

1987 ◽  
Vol 65 (8) ◽  
pp. 1996-2007 ◽  
Author(s):  
Susan M. Bower
Keyword(s):  
Nervous Tissue ◽  
Sea Water ◽  
Culture Media ◽  
Cell Periphery ◽  
Haliotis Rufescens ◽  
Small Juvenile ◽  
Nutrient Culture ◽  
Multiple Fission ◽  
Pathogenic Parasite ◽  
Active Swimming

Labyrinthuloides haliotidis n.sp. is an achlorophyllous eucaryotic protist that is pathogenic to juvenile abalone (Haliotis kamtschatkana and Haliotis rufescens) less than 190 days of age (postsetting). Within the muscle and nervous tissue of the head and foot of susceptible abalone and in axenic nutrient culture media at 10 °C, vegetative stages of L. haliotidis proliferated by binary fission and produced ectoplasmic nets from sagenogenetosomes located on the cell periphery. When the abalone died and the parasites were released from the decaying tissue or when culture forms were washed free of nutrient medium and placed in sea water, internal multiple fission (sporulation) occurred within some cells, producing zoosporoblasts. After 24 to 72 h of incubation at 10 °C, the zoosporoblasts ruptured to release from 3 to about 10 infective biflagellated zoospores. After about 24 h of active swimming, or on contact with a glass surface, the zoospores shed their flagella. Ultrastructure of vegetative stages and zoospores related this species more closely to the thraustochytrids than to the labyrinthulids. Confusion still prevails concerning the higher taxonomic affinities of this group of organisms. In keeping with recent publications on the taxonomy of the kingdom Protozoa, L. haliotidis was considered to be a protozoan of the phylum Labyrinthomorpha and not allied with the fungi.

Mercury in the Marine Environment: Concentration in Sea Water and in a Pelagic Food Chain

1973 ◽  
Vol 30 (2) ◽  
pp. 293-295 ◽  
Author(s):  
P. M. Williams ◽  
H. V. Weiss
Keyword(s):  
Biological Activity ◽  
Bottom Sediment ◽  
Food Chain ◽  
Mercury Concentration ◽  
Vertical Profile ◽  
Sea Water ◽  
Mercury Content ◽  
Trophic Levels ◽  
Single Station ◽  
Almost All

Mercury in seawater, in a pelagic food chain, and in bottom sediment was determined at a single station 430 km southeast of San Diego, California. The concentration of mercury in zooplankton slightly increased with depth of collection. The mercury content in almost all of the higher trophic levels of organisms collected at greater depths was indistinguishable from the concentration of mercury in zooplankton at these depths. Mercury concentration in the seawater column was essentially constant below 100 m and significantly higher at the surface. This vertical profile of mercury content is not ascribable to biological activity.

On the use of ammonium for buoyancy in squids

1979 ◽  
Vol 59 (2) ◽  
pp. 259-276 ◽  
Author(s):  
M. R. Clarke ◽  
E. J. Denton ◽  
J. B. Gilpin-Brown
Keyword(s):  
Developmental Stage ◽  
Sea Water ◽  
The Body ◽  
The Other ◽  
Neutral Buoyancy ◽  
Rich Solution ◽  
Almost All ◽  
Neutrally Buoyant

Squids (teuthoids) fall into two distinct groups according to their density in sea water. Squids of one group are considerably denser than sea water and must swim to stop sinking; squids in the other group are nearly neutrally buoyant. Analyses show that in almost all the neutrally buoyant squids large amounts of ammonium are present. This ammonium is not uniformly distributed throughout the body but is mostly confined to special tissues where its concentration can approach half molar. The locations of such tissues differ according to the species and developmental stage of the squid. It is clear that the ammonium-rich solution are almost isosmotic with sea water but of lower density and they are present in sufficient volume to provide the main buoyancy mechanism of these squids. A variety of evidence is given which suggests that squids in no less than 12 of the 26 families achieve near-neutral buoyancy in this way and that 14 families contain squids appreciably denser than sea water [at least one family contains both types of squid]. Some of the ammonium-rich squids are extremely abundant in the oceans.

Eco-Physiological Studies of an Intertidal Crustacean, Pollicipes Polymerus (Cirripedia, Lepadomorpha)

1972 ◽  
Vol 57 (1) ◽  
pp. 83-102
Author(s):  
H. J. FYHN ◽  
J. A. PETERSEN ◽  
K. JOHANSEN
Keyword(s):  
Water Loss ◽  
Volume Regulation ◽  
Free Amino ◽  
Heat Load ◽  
Laboratory Experiments ◽  
Sea Water ◽  
Physiological Responses ◽  
The Body ◽  
Air Exposure ◽  
Pollicipes Polymerus

1. Physiological responses to environmental stresses of the intertidal cirriped Pollicipes polymerus have been studied by combined field and laboratory experiments. 2. The body temperature of air-exposed animals is always lower than expected from the heat load. Evaporation from the peduncle is responsible for the heat loss. 3. The rate of water loss by evaporation from the peduncle cuticle is 1.5 µl/cm2 h mmHg both at 21 and 27 °C. The transpiration is proportional to the saturation deficit of the air. The water loss from the capitulum is negligible in comparison to that from the peduncle. 4. The haemolymph osmolality of animals in the field increases during exposure to sunshine and decreases during exposure to rain. The increase in haemolymph osmolality during desiccation is equal to that calculated from the decrease in body water. The water loss during air exposure is adequately replaced during submersion, probably by osmosis. 5. Pollicipes is an osmoconformer but is 5-20 m-osmoles hyperosmotic. It tolerates sea-water dilutions down to about 50%. The hyperosmolality seems to be balanced by a high internal hydrostatic pressure. 6. An excretory activity is observed. The excretion is isosmotic to the haemolymph and is possibly an ultrafiltrate of the latter. 7. The muscle cells show volume regulation, but free amino acids seem to be unimportant in regulation of intracellular osmolality. The concentration of ninhydrinpositive substances in the muscle tissue is about 200 mM for animals in full strength sea water.

Spear Phishing

2019 ◽  
pp. 635-650
Author(s):  
Arun Vishwanath
Keyword(s):  
Computer Network ◽  
Relative Effectiveness ◽  
Social Science Research ◽  
Science Research ◽  
Cyber Attack ◽  
Policy Suggestions ◽  
Terrorist Groups ◽  
Use Of The Internet ◽  
Almost All ◽  
Gain Access

The ubiquitous use of the Internet has made it possible for terrorist groups to remotely foment attacks with little risk of capture. Among the newest forms of attacks is cyber hacking, which has seen increased use by terrorist groups for acts ranging from pinpointing targets for assassination to holding organisations hostage and embarrassing governments. In almost all these attacks, spear phishing is the vector used to gain access to a computer network – making it imperative that policymakers find ways to stop it. This chapter provides an overview of the different types of spear phishing attacks and the reasons they succeed. The chapter then provides an overview of the different strategies being used to combat it and their relative effectiveness. Drawing from the latest social science research and from initiatives that have worked around the world, the chapter culminates with six policy suggestions, which could significantly reduce the effectiveness of spear phishing and protect nations from a major cyber attack.

scholarly journals The Formation of Brine Drainage Features in Young Sea Ice

1975 ◽  
Vol 14 (70) ◽  
pp. 137-154 ◽  
Author(s):  
Lars Ingolf Eide ◽  
Seelye Martin
Keyword(s):  
Sea Ice ◽  
Laboratory Experiments ◽  
Sea Water ◽  
Salt Water ◽  
Pressure Head ◽  
Drainage Channels ◽  
The Difference ◽  
Thin Plastic ◽  
Ice Water ◽  
Brine Channel

Laboratory experiments on the growth of sea ice in a very thin plastic tank filled with salt water, cooled from above and insulated with thermopane, clearly show the formation and development of brine drainage channels. The sea-water freezing cell is 0.3 cm thick by 35 cm wide by 50 cm deep; the thermopane insulation permits the ice interior to be photographed. Experimentally, we observe that vertical channels with diameters of 1 to 3 mm and associated smaller feeder channels extend throughout the ice sheet. Close examination of the brine channels show that their diameter at the ice-water interface is much narrower than higher up in the ice, so that the channel has a “neck” at the interface. Further, oscillations occur in the brine channels, in that brine flows out of the channel followed by a flow of sea-water up into the channel. Theoretically, a qualitative theory based on the difference in pressure head between the brine inside the ice and the sea-water provides a consistent explanation for the formation of the channels, and the onset of a convective instability explains the existence of the neck. Finally, an analysis based on the presence of the brine-channel neck provides an explanation for the observed oscillations.

scholarly journals The Formation of Brine Drainage Features in Young Sea Ice

1975 ◽  
Vol 14 (70) ◽  
pp. 137-154 ◽  
Author(s):  
Lars Ingolf Eide ◽  
Seelye Martin
Keyword(s):  
Sea Ice ◽  
Laboratory Experiments ◽  
Sea Water ◽  
Salt Water ◽  
Pressure Head ◽  
Drainage Channels ◽  
The Difference ◽  
Thin Plastic ◽  
Ice Water ◽  
Brine Channel

Laboratory experiments on the growth of sea ice in a very thin plastic tank filled with salt water, cooled from above and insulated with thermopane, clearly show the formation and development of brine drainage channels. The sea-water freezing cell is 0.3 cm thick by 35 cm wide by 50 cm deep; the thermopane insulation permits the ice interior to be photographed. Experimentally, we observe that vertical channels with diameters of 1 to 3 mm and associated smaller feeder channels extend throughout the ice sheet. Close examination of the brine channels show that their diameter at the ice-water interface is much narrower than higher up in the ice, so that the channel has a “neck” at the interface. Further, oscillations occur in the brine channels, in that brine flows out of the channel followed by a flow of sea-water up into the channel. Theoretically, a qualitative theory based on the difference in pressure head between the brine inside the ice and the sea-water provides a consistent explanation for the formation of the channels, and the onset of a convective instability explains the existence of the neck. Finally, an analysis based on the presence of the brine-channel neck provides an explanation for the observed oscillations.

scholarly journals ALTERNATIF TEKNOLOGI PENGOLAHAN AIR UNTUK MEMENUHI KEBUTUHAN AIR BERSIH DI DAERAH PEMUKIMAN NELAYAN Studi Kasus Perencanaan Penyediaan Air Bersih di Daerah Pedesaaan Nelayan Kab. Pasir, Kalimantan Timur

2018 ◽  
Vol 3 (1) ◽  
Author(s):  
Taty Hernaningsih ◽  
Satmoko Yudo
Keyword(s):  
Water Treatment ◽  
Surface Water ◽  
Sea Water ◽  
Water Source ◽  
Treatment Technology ◽  
Deep Well ◽  
Primary Water ◽  
Daily Water ◽  
Water Treatment Technology ◽  
Almost All

Primary water source of people in  fisherman area in Kabupaten Pasir, Kalimantan Timur for daily water need generally is from  surface water  or deep well. Surface water is affected by water tide of sea water, so that almost all the time  in a year the water quality is salty or brakish. Beside high salt concentration, deep well quality  is also worst.  This is caused by poor environmental sanitation of fisherman community.  Rainy water use as water source alternative in problem solving for limited water drinking only provide in rainy season. Other alternative, people must find from other area where is far from their house or buy water with expensive price. To solve this critical problem is required the application of suitable  water treatment technology. This water treatment  technology must produce drinking water that meet technical standard and　 the technology is applicable, easy and cheap in operation and maintenance because it is hoped that community in that area can manage, operate  and maintenance. Kata Kunci : Penduduk nelayan, penyediaan air bersih, teknologi pengolahan air bersih.

scholarly journals PLeveraging Django and Redis using Web Scraping

2020 ◽  
Vol 9 (1) ◽  
pp. 2103-2105
Keyword(s):  
World Wide ◽  
Data Extraction ◽  
Web Browser ◽  
Server Side ◽  
Web Scraping ◽  
The World ◽  
Hypertext Transfer Protocol ◽  
Almost All ◽  
Readable Format ◽  
Gain Access

Web scraping is also known as data scraping and it is used for extracting data from sites. The software used for this may directly access the World Wide Web by using the Hypertext Transfer Protocol or by using a web browser. Over the years, due to advancements in web development and its technology, various frameworks have come in use and almost all of websites are dynamic with their content being served from CMS. This makes it tough to extract data since there is no common template for extracting data. Hence, we use RSS. Rich Site Summary is a kind of timeline allowing users and also applications to gain access to the updates on websites in a standardized, computer-readable format. This project combines the use of RSS to extract data from websites and serve users in a robust and easy way. The differentiation is that this project uses server side caching to serve users almost instantaneously without the need to perform data extraction from the requested site all over again. This is done using Redis and Django.

scholarly journals Reforming Medicaid and Vulnerable People

2016 ◽  
Vol 20 (1) ◽  
pp. 33
Author(s):  
Arnold Birenbaum
Keyword(s):  
People With Disabilities ◽  
Federal State ◽  
Access To Health Services ◽  
The Public ◽  
Insurance Program ◽  
Political Clout ◽  
Access To Health ◽  
Vulnerable People ◽  
Almost All ◽  
Gain Access

Medicaid, the federal-state financed program that assists people to gain access to health services when they cannot afford them, has been inthe news of late. Unfortunately the news is disquieting for people who count on this program for health care and rehabilitation services. Change is not always the friend of vulnerable people, and in this instance, it can be downright disruptive when it comes to accessing services. Because they are not well organized, people with Medicaid coverage do not have political clout, even though more people are covered by Medicaid than Medicare (e.g., the public insurance program for almost all people over the age of 65 and some people with disabilities). New Bush administration proposals and ongoing practices could be particularly harsh for people with disabilities.

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