Parasites: 10 frightening facts!

Ten Things You Never Wanted To Know About Parasites
1: They're everywhere!You cannot always see parasites, but rest assured that a whopping 75% of the world's creatures belong to this family. And did you know the average human body alone is known to host over a million of them?2: Gut feelingsIf you don't have at least one kind of worm residing in your guts, you're in the minority. After all, over three-quarters of the world's population keep them cosy. Though most of them are small, the biggest tapeworm ever recorded was over 60 feet long. Nice!3: HookwormsA staggering 1.3 billion of the world's population suffer from hookworms, minute monsters that cause anaemia by sucking the blood from the intestinal lining. 4: SmallpoxSmallpox was officially eradicated in 1980, but did you know that the micro parasites that cause this deadly disease currently lie dormant in the ice of Greenland? Some scientists are even worried that global warming could actually free them from captivity.5: EbolaSome parasites are content to feed on bits of you over time. Others are less polite. The dreaded Ebola parasite will, for example, attack internal organs and eat into collagen, which is the connective tissue that holds the human body together.6: Pregnant protectionPregnant women may have a special reason to resent parasites. Scientists believe that morning sickness is the body's way of protecting mother and child from parasitic infection.7: Guinea WormsThe good thing about Tapeworms is that they have the decency to stay hidden. Not so the Guinea Worm. Ingested via contaminated water, the larvae burrow into the intestines and eventually emerge, fully grown, from the skin.8: PinwormsAs prevalent in the West as anywhere else, Pinworms are staple-sized intestinal blighters that crawl out of your backside while you're asleep and deposit their eggs on your bedding.9: Men more at threatMen are twice as likely as women to die of parasite-induced causes. This is thought to be because men tend to be larger and present a greater target.10. Most deadly parasiteThe worst parasite of all is the one that causes malaria. Currently killing a person every 30 seconds, malaria has been responsible for over half of all human deaths since the Stone Age.

LIMULUS AMEBOCYTE LYSATE

Limulus amoebocyte lysate (LAL) is an aqueous extract of blood cells (amoebocytes) from the horseshoe crab, Limulus polyphemus. LAL reacts with bacterial endotoxin or lipopolysaccharide (LPS), which is a membrane component of Gram negative bacteria. This reaction is the basis of the LAL test, which is used for the detection and quantitation of bacterial endotoxins.The LAL cascade is also triggered by (1,3)-β-D-glucan. Both bacterial endotoxins and (1,3)-β-D-glucan are considered "Pathogen-Associated Molecular Patterns", or PAMPS, substances which elicit inflammatory responses in mammalian systems.

There are three basic LA test methodologies: gel-clot, turbidimetric, and chromogenic. The primary application for LAL is the testing of parenteral pharmaceuticals and medical devices that contact blood or cerebral spinal fluid. In the United States, the FDA has published a guideline for validation of the LAL test as an endotoxin test for such products

The LAL Test
LAL provides significant benefits to each of us. Have you ever had surgery? Have you ever taken an antibiotic? The FDA now requires an LAL test for injectable and intravenous drugs as well as for screening prosthetic devices such as heart valves or hip replacements. LAL is also used to diagnose spinal meningitis and other diseases.

LAL Production
In order to produce LAL, large horseshoe crabs are caught, examined for health, and bled using a stainless steel needle that is inserted into their circulatory system. The crab's blood is centrifuged to separate the amoebocytes from the liquid plasma. The amoebocytes are then freeze-dried and processed for use in the pharmaceutical industry. Horseshoe crabs are not seriously harmed during this process, and studies have indicated that bled horseshoe crabs have a relatively low mortality rate (10%). People in the LAL business carefully monitor their methods to guard their "golden goose." One quart of LAL is worth $15,000!
Three United States companies produce nearly all Limulus Amoebocyte Lysate products used worldwide. Associates of Cape Cod: http://www.acciusa.com/Cambrex: http://www.cambrex.com/default.aspCharles River Endosafe: http://www.criver.com/products/endotoxin/index.html

New Discoveries
Alternatives to LAL are currently being investigated in India (http://www.nio.org) and China. TAL, or Tachypleus amoebocyte lysate, functions similarly to LAL, aiding in the detection of gram-negative bacteria.
Scientists in Singapore are working to clone the toxin-detecting gene in horseshoe crab blood. If the gene can be cloned, LAL derivatives can be prepared without the harvest of horseshoe crabs for blood extraction.

Mycoplasma laboratorium - a synthetic bacterium

It is debatable whether the claim the famous and controversial scientist, Craig Venter, and his team working at the Maryland-based J. Craig Venter Institute made last year — in a patent filed to produce a truly ‘synthetic’ bacterium with minimal genomes — is significant. While the genome of the bacterium was produced synthetically in the laboratory, a ‘synthetic’ bacterium, which has been named Mycoplasma laboratorium in the patent and will eventually be created using the minimal genome, cannot in the strict sense be called man-made. To be called synthetic, no naturally available component should be used. In that sense, the scientists from the reputed institute, the first to publish the sequence of the human genome, will at best be able to produce a semi-synthetic M. genitalium bacterium. The synthetic genome produced by them will be put into a naturally occurring cell that will have only its nucle us removed. While this will ensure the removal of the genetic material, the cell will still contain many other materials without which the M. genitalium genome introduced cannot survive and reproduce. The procedure described by them is, in many ways, similar to that followed for producing embryonic stem cells. Many scientists are working to produce a truly synthetic organism that has no trace of natural components. Synthetic flu virus and polio virus were built from scratch using the genome sequence a few years ago. Yet they were not considered synthetic as viruses need a host to replicate.
Apart from producing the synthetic genome, their achievement has been to arrive at the minimum number of essential genes needed for sustaining life. The wall-less M. genitalium bacterium with just 482 genes, the smallest number to b e seen in any naturally occurring organism, is the best experimental platform and hence the natural choice for scientists to produce a bacterium with ‘minimal genome.’ The patent filed by them cites 381 as the minimal genome for the M. laboratorium that would allow the bacterium to replicate in a controlled environment. This is one less than the number they had stated in a paper published in a journal last year. While their work on the minimal genome and synthetic genome is indeed remarkable — as it lends itself to a variety of applications — filing the patent application has irked many. While patents have been granted to individual genes, this is the first time a patent has been filed for an entire genome sequence. If granted, it will handicap researchers in the area and may not augur well for the advancement of science.

Corynebacterium diphtheriae

Corynebacterium diphtheriae are Gram-positive, nonmotile, rod-shaped bacteria that do not form spores or branch. They do not have a typical gram-postive cell wall. It consists of arabinose, galactose, disminopimelic acid, and short chain mycolic acids. In the mycolic acid, chains of 28-40 carbons are common. They are chemoorganotroph and aerobic, exhibiting a fermentative metabolism under certain conditions. They are fastidious organisms, growing slowly on even an enriched medium. They form irregular shaped, club-shaped or V-shaped arrangements in normal growth. Their arrangement resembles Chinese letters because they undergo snapping movements just after cell division.
C. diphtheriae is an infectious disease that spreads from person to person by respiratory droplets from the throat by coughing, sneezing, or even laughing. It affects the tonsils, throat, and nose and can also affect the skin. These bacteria can lead to breathing problems, heart failure, paralysis and even sometimes death.
Its early symptoms can have C. diphtheriae mistaken for a severe sore throat. Its symptoms make a low-grade fever and the lymph nodes are enlarged in the neck. The symptoms may also appear as skin lesions that may be painful, red and swollen. These symptoms usually appear within 2 to 4 days after the infection has taken place, but they can also range anywhere from 1 to 6 days. Anyone who is carrying diphtheria germs are however contagious for up to 4 weeks without any antibiotic therapy.
The tetanus-diphtheria (Td) vaccine should be given to anyone who either: did not receive a primary series of immunization against tetanus and diphtheria during childhood, or who did not receive a booster dose within the past ten years. This vaccine stimulates the body to make neutralizing antibodies against the binding component of the diphtheria exotoxin. Once this antibody binds to the exotoxin, the toxin itself can no longer bind to the receptors on the host cell membrane. This vaccine is very safe and does not usually produce any side effects. This vaccine is not a cause for diphtheria.
There are many known cases in the world dating back to as early as the 4th century B.C., when Hippocrates provided the first clinical description of diphtheria. In the 17th century it swept through Europe and became to acquire nicknames. In Spain the disease was known as “El garatillo”, which means “the strangler”, and in Italy it was known as “the gullet disease”. It reached the American colonies in the 18th century around 1735 and often killed whole families in a few weeks.
In 1883, Klebs first described the bacterium that caused diphtheria. It was later cultivated by Loeffler in 1884, which he used Koch’s postulates and identified Corynebacterium diphtheriae as the agent of the disease. Loeffler also discovered that C. diphtheriae produced a toxin, and he provided the first description of the bacterial exotoxin. It was next tested on lab animals in 1888 by Roux and Yersin. They demonstrated the presence of the toxin in the cell-free culture fluid of C. diphtheria by injecting the animals, which caused the manifestation of diphtheria.
In the 1900’s, in the United States, the disease was very common, especially in children, making it one of the leading causes of death to infants and children. In the 1920’s there were 150,000 cases and 13,000 deaths resulted from those known cases. In 1945, after immunization was introduced, there were only 19,000 cases and a decreasing number of deaths, also. In the 1970’s, 196 cases per year were reported. In the 1980’s, the cases in the United States has dropped to 24, two of the cases resulted in death, and 18 occurred in people over the age of 20 years old.