Karenia brevis usually reproduce by asexual process, dividing into two cells, then into four and so on. Firstly, cysts of the karenia brevis lay on the ocean floor and might stay in the ground for years, without being disturbed. Oxygen and other conditions, such as the right temperature and pressure are essential for the beginning of the germination process. When the temperature increases, as well as the light absorbsion, the cyst breaks open and a swimming cell appears to the ocean. After a few days time the cell reproduces by simple division and as a result hundred of cells will reproduced within weeks, having the same number of chromosomes in the nucleus.
However, is really important to mention that karenia brevis might have sexual reproduction and a new life change and that happens only when the organism cannot have access in available nutrients, thus growth stops and gametes are formed. During gametogenesis the chromosomes in the nucleous reassume a typical dinokaryotic appearance, the nuclear envelope appears in all mitotic stages and the mitotic spindle is extracellular. Spindle microtubules pass through furrows and tunnels that form in the nucleus at prophase (Dodge 1987).
Some microtubules contact the nuclear envelope, lining the tunnels at points where the chromosomes also contact. The chromosomes usually have differentiated, dense regions inserted into the envelope. After that, the two cells (gametes) join together. Syngamy involves equal motile gametes and is called isogamy. Then, the formed cell develops into a zygote by homothallism, which is the gamete fusion in clonal strains. The product of gamete fusion is a planozygote, which may remain motile for hours or a few days. Eventually a non-motile thick-walled resting cyst (hypnozygote) is formed. Excystment occurs after a varying length of time of inactiveness. Meiosis is heralded by a peculiar churning and rotation of the nucleus, a process called nuclear cyclosis associated with the pairing of homologous chromosomes .Meiosis may occur before or after the encystment and is normally accomplished in two successive divisions. The mobile zygotes follow the long-term encystment (resting cysts).
The Term Paper on Stem Cell
Abstract There are several types of stem cells being used in stem cell research and therapy today. They are embryonic, adult and induced pluripotent stem cells. Each will be discussed further. This topic has stirred much moral, ethical and political debate as whether cells from fetuses should be used in this research. This impacts governmental policies on laws and funding. Another issue that must ...
The inactive cysts fall into the bottom of the ocean until the time is appropriate for another germination (Mona Hoppenrath and Juan F. Saltarriaga, 2008).
Many scientists have done research about the life cycle of Karenia brevis in order to find out if is connected with the main effects of red tides in humans and animals. Karen Steidinger, a scientist of the Florida Fish and Wildlife Conservation Commision, also called “the mother of the red tide research” said about the life cycle of Karenia brevis: “Basically we know it is born at sea. Then something happens to fertilize it. As it moves forward shore, the dead fish fertilize it even more. Then it is over”. Steidinger wants to prove a theory of hers that the sexual stages of that life cycle play a fundamental role in the onset of red tide and if she manages to prove that, then she might be able to use her results for preventing further deaths of ocean species (Andy Lindstrom, 2007).
When karenia brevis blooms complete their life cycle, they need to be initiated and transport to other areas. That happens in four stages. Firstly, the blooms are introduced into an area ( the area in which they are born), then they need to grow and increase their population. In addition, they have to maintain and be moved offshore or inshore by wind and sea currents. The final stage involves the dissipation and termination of that process, while winds and currents disperse the cells and transfer them in new water masses.
The Essay on Aquatic Life Ddt Pesticides Fish
The very basic overall concept behind this article is that pesticides kill aquatic life. Needless to say, this is a bad thing. This article refers to cases of pesticide spraying back in the 1950's. Different pesticides sprayed all over Canada and the United States, all had very negative effects on the life in streams and rivers. One of these pesticides that is most harmful to the environment is ...
In conclusion, red tide is a serious phenomenon, which is really possible to influence the animal food chain and harm peoples’ health, thus, many programmes are developed and try to give their contribution by doing researches in order to predict and prevent their destructive effects. Peoples’ health as well as life underwater need to be conserved and we hope that future discoveries will restore the life chain in sea water by the elimination of these harmful organisms.
Karenia brevis is a photosynthetic dinophlagellate with strongly dorsoventrally flattened squarish cells. The organism has a length of 23-24 μm, a width of 24-36 μm and a depth of 10-15 μm. The main parts of the organism are:
•The apical groove at the anterior part of the cell extending on both the ventral and dorsal sites.
•The cingulum, a furrow encircling the cell in the middle.
•The cingular ridges, which are longitudinal ridges in the cingulum.
•The longitudinal flagellum which is like a rudder and guides the cell during locomotion.
•The transverse flagellum which pushes the cell to move forward.
•The sulcus which is the longitudinal area on the ventral surface of the cell that houses the longitudinal flagellum.
•The theca which contains multiple membrane layers with vesicles
•The chloroplasts, organelles where photosynthesis takes place
Karenia brevis has the ability to increase by creating visible patches near
the water’s surface and as an organism can last three to five months until it is destroyed. However, the most important thing about this organism is that it produces strong chemical neurotoxins, called brevetoxins that can harm the aquatic species. These brevetoxins bind to voltage-gated sodium channels in nerve cells, as a result normal neurological processes to disrupt and that causes the illness described as Neurotoxic Shellfish Poisoning. The effect on animals is fatal, while Karenia brevis is responsible for the death of millions of fish, invertebrates such as clams and oysters, marine mammals and birds. People can be infected by brevetoxin when they consume infected fish or oysters and they can be in real danger if the concentration of this neurotoxin is really high in the body because it might cause death. Normally though the effects on humans are more related to the appearance of specific symptoms like tingling in lips, tongue and throat, asthmatic symptoms, diarrhea and vomiting and a bizarre feeling of temperature confusion i.e. hot feels cold and vice versa (Florida Fish and Wildlife Conservation Commission).
The Essay on An Anatomy And Physiology Of The Organelles Of The Cell
An Anatomy and Physiology of the organelles of the cell In this paper I will examine an anatomy and physiology of the organelles of the cell. The branch of science which research deeply cells is called cytology. I will not deepen in the cytology because it is a really huge branch of science. What I want to do is make a brief introduction and acquaint you with main cytology thesis. After this I ...
Those symptoms can become really dangerous if they are not treated properly, thus treatment should be given immediately, when the patient appears the symptoms. The first thing a patient should do is to wear filter masks to decrease the asthmatic symptoms. Then specific asthma medications are advised like: Albuterol, Dipheniramine, Cromolyn, Prednisone, Brevenal, and bronchodilators as well as the use of antiemetics and the consumption of intravenous fluids (Professor Lora E Fleming lecture, University of Miami) .
