Save the Big Guns for the Big Battles

Our bodies war with the microbial world. Microbial invaders seek to invade and sap our power. They produce toxins (proteins in most cases) that destroy our cells and cause damage. These bacteria are toxin manufacturing plants and oftentimes contain more toxin inside themselves than they release into their environment. Our immune system responds to these invaders by sending white blood cells called polymorphoneutrophils or PMN’s. PMN’s gobble up (phagocytosis) the invaders and slowly destroy them. The toxins are inactivated and destroyed within the PMN’s and very little fallout occurs when our immune system destroys bacteria. When our immune systems are overwhelmed bacteria start winning the war. To stop this we use antibiotics to destroy these nasty microbes. Antibiotics buy our immune systems valuable time to recruit other members of our immune system to join in the fight. Unfortunately, using antibiotics can cause damaged and dying bacteria to release their toxins too quickly. Not enough PMN’s are around to gobble up these microbes and damage can occur to the patient.

Sometimes we get too hurried and want the antibiotics before they are necessary. Overkill with antibiotics can sometimes be worse than just giving our immune systems time to contain and eliminate the infection. Diarrhea due to bacterial invaders is a case in which we sometimes bring the big guns (antibiotics) out too soon. Most diarrheal infections can be resolved by our immune systems. The only treatment necessary is to keep the patient from dehydrating. This can be done by giving the patient plenty of fluids.

Recently, a study funded by the National Institute of Diabetes and Digestive and Kidney Diseases (an institute at the National Institutes of Health, USA) demonstrated that bringing our the big guns, antibiotics, too soon can be life threatening. They showed that antibiotics given to children as a treatment for diarrhea caused by Escherichia coli O157:H7 results in more problems than not treating the infection with antibiotics. These researchers studied 71 children who were infected with Escherichia coli O157:H7. Of the 9 who received antibiotics, 5 (56 percent) developed hemolytic uremic syndrome or HUS, compared with 5 (8 percent) of the 62 who developed HUS in the group that did not recieve antibiotics.

By giving these children antibiotics the bacteria were rapidly killed. This rapid killing of the bacteria resulted in large amounts of toxin being released to the kidneys. The kidneys were damaged by the toxin and unable to function properly resulting in HUS. From 3-5 percent of children with HUS die and of the survivors 10-40 percent suffer from permanent kidney damage.

Bringing out the big guns too soon can cause more harm than good. Antibiotics

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Iron Poor Blood Doesn’t Hurt Lyme Bacteria

One important part of our diet is iron. Iron is a metal that is very important in helping us get energy from our foods. Without adequate amounts of iron we will become very tired and eventually very sick. That is because iron is involved in the end stages of energy production. For example when our bodies breakdown sugar we end up giving off lactic acid, carbon dioxide, water, and storable energy in the form of ATP (adenine triphosphate). When needed the ATP will breakdown to ADP (adenine diphosphate) releasing this stored energy. To get the most ATP out of each sugar molecule we use iron containing molecules called cytochromes. Without these cytochromes our bodies would soon lack the energy needed to survive.

Iron also transports oxygen to the cells of our bodies via our red blood cells when attached to a protein called hemoglobin. We need to live in an oxygen environment because oxygen is also involved in the end stages of ATP production. Oxygen accepts the leftover electrons from sugar breakdown and with a couple of hydrogen atoms makes water. Water is a byproduct of sugar breakdown and energy generation. Our bodies consider iron such a precious metal that it produces iron binding proteins that hold on to any extra iron that maybe in our bodies.

We are not the only ones that need iron to survive. Most bacteria also need iron to live. They, like us, use iron to help in generating ATP. Bacteria have developed very elaborate means to get iron from the environment so they can survive. In fact the iron binding proteins in our bodies are important in preventing many bacterial illnesses. If all the available iron is bound to these proteins many bacteria simply die of ATP starvation. To get around this particular defense mechanism most bacteria that infect humans produce compounds that grab the iron from our iron binding proteins.

The Lyme disease bacterium has developed another way around this problem. It does not need iron at all. Researchers at the University of Georgia have discovered that the Lyme disease bacterium, Borrelia burgdorferi, only has 5 molecules of iron per cell. If given too much iron it will die. It enjoys iron-free environments. Instead of using iron to generate ATP it uses manganese. Without the need for iron this particular bacterium doesn’t have to fight with our iron binding proteins to survive and can live quite well in our bodies for long periods of time.

This ability to live without iron is very rare. Only one other bacterium, Lactobacillus planatarum, has been identified that doesn’t need iron to live. This knowledge may help Lyme disease researchers better understand how this organism causes disease and may also help in the design of antibacterial compounds that could kill these unique microorganisms. Life can be very interesting. You think you have it all figured out and POW some microbe or another does things just a little bit differently

Our Hamburgers are Contaminated!

Previous estimates by the United States Department of Agriculture’s (USDA) Food Safety and Inspection Service (FSIS) calculated that about 5 percent of the hamburger processed in the U.S. was contaminated with Escherichia coli O157:H7.
This particular bacteria causes about 62,000 cases of food poisoning in the United States each year. Infection with this bacterium is especially dangerous to the elderly, the young, and the immunocompromised. People in these categories can experience bloody diarrhea and kidney failure. A recent report by the FSIS using a much more sensitive test indicated that almost 90 percent of the hamburger lots tested were contaminated with Escherichia coli O157:H7. This is not good news. However, you must take some of this alarming news with some amount of cautious examination. Some of those lots of hamburger only contained 100 Escherichia coli O157:H7. Those lots consist of 3000 pounds of hamburger. If you were to eat a quarter pound burger and if the Escherichia coli O157:H7 were evenly distributed you would have to eat 120 uncooked quarter pound hamburgers to get one organism. The dose of Escherichia coli O157:H7 needed to cause illness is about 10 organisms. This means that you would have to eat 1200 uncooked quarter pound hamburgers to get sick.

I don’t want you to think that I am downplaying the importance of these findings. Not all hamburger is kept at the proper temperature to prevent growth of the bacteria. One hundred organisms could quickly become 1 million organisms. Nor are bacteria evenly distributed in the meat. Some poor unfortunate person may get the only undercooked hamburger from the lot with 10 Escherichia coli O157:H7 in it and get really ill. Many of the lots of the hamburger FSIS tested contained much higher numbers of Escherichia coli O157:H7 in the meat. The bad thing about these bacteria is that you can NOT tell if the meat is contaminated. It will look fine and smell fine. However, if you do not cook it properly and are at the right age for serious complications you could become very ill.

The take home message of this story is that most hamburger packages you get from the store are contaminated with disease causing bacteria. Many people love to eat hamburger. You should not stop eating hamburger but instead you should prepare it wisely and cook it until it is well done.

You don’t have to be an unknowing victim of contaminated hamburger. Most food poisonings do NOT occur in restaurants. It is just that those outbreaks of food poisoning are more likely to be reported to the public. Uncle Bill’s Saturday night hamburger feast with four of his friends

Alcohol with Less Severe Hangovers Created: New Scientific Discovery Reduces the After-Effects of Drinking

Most people at some point in their lives can recall a time when they have had ‘one too many’ and suffered the next day from the effects of alcohol. A team of scientists in Korea may now have found a solution to stop those ‘morning after’ feelings.

Alcohol with a Higher Oxygen Content Produces Fewer after Effects

A team of scientists from Chungnam National University in Korea carried out experiments where participants were given alcoholic drinks with varying oxygen content levels. Results showed that those participants who had greater levels of oxygen within their drinks sobered up significantly quicker than those with lower levels in their beverages.

According to The Telegraph newspaper, when a person drinks alcohol, Oxygen in the body turns the alcohol into water and carbon dioxide. The study in Korea found that when Oxygen concentrations in alcoholic drinks are increased, it would appear that the process of the human body dealing with alcohol and breaking it down is speeded up.

The Common Hangover

The effects that alcohol will have on a person varies between individuals. Some people have a higher tolerance to alcohol than others and factors such as a person’s height, build and age can also lead to how well the body deals with the consumption of alcohol.

According to http://www.howstuffworks.com, other physical factors such as;

  • How tired a person is before drinking alcohol,
  • How much they have had to eat before drinking alcohol,
  • how well hydrated they are beforehand, and,
  • Level of physical activity a person does whilst drinking alcohol ,

Can all affect how a person responds when consuming alcohol; this is one of the reasons why individuals find their tolerance to alcohol varies depending on their situation when consuming an alcoholic drink. Those people who have been dancing at the same time as drinking may find that they suffer more severe hangover the next day due to the added effects of dehydration that the dancing caused.

Scientists don’t fully understand all the causes of hangovers but the primary symptoms including headache’s, nausea and vomiting result from a combination of various chemical imbalances being caused in the body by alcohol being absorbed (www.howstuffworks.com).

Hangovers won’t be a Thing of the Past

The new alcohol developed by the Korean University won’t mean that those consuming it will feel no effects at all. The scientists point out that their work won’t lead to hangover free alcohol but could lead to alcohol that has the same level of alcoholic content but owing to its higher levels of oxygen, creates less severe hangovers.

The full results of the experiment can be read in the Alcoholism: Clinical and Experimental Research.

Traveler’s Diarrhea: Risk and Associated Pathogens

Traveler’s diarrhea is characterized by the onset of loose, watery or semi-formed stools, of an urgent nature, accompanied by abdominal cramps. Vomiting may also accompany diarrhea (15% of cases). Symptoms may be preceded by flatulence and abdominal cramping. The illness is usually self-limited lasting 3-4 days.

Traveler’s diarrhea is most commonly caused by bacteria (85%), but can also be caused by parasites (10%) and viruses (5%). The risk of acquiring traveler’s diarrhea is dependent on your travel destination. Countries are classified as low-risk, intermediate-risk and high-risk (see Map). The Centers for Disease Control and Prevention (CDC) estimated that 30-50% of travelers will develop traveler’s diarrhea during a 1- to 2-week stay in high-risk areas.

Risk of traveler’s diarrhea varies seasonally in temperate climates, listed in the dictionary of biology.

Low-risk countries:

  • Canada
  • United States
  • AustraliaNew Zealand
  • Japan
  • northern and western Europe.

Intermediate-risk countries:

  • Eastern Europe
  • South Africa
  • Caribbean Islands

High-risk countries:

  • Asia
  • Middle East
  • Africa
  • Central and South America

Ingestion of contaminated food or water is responsible for most cases of traveler’s diarrhea, and most of these are caused by bacteria. A number of different bacteria may cause traveler’s diarrhea:

Enterotoxigenic E. coli (ETEC):

  • large inoculum required to produce illness,
  • associated with sanitation breakdown,
  • common in developing countries,
  • symptoms include watery diarrhea and cramps,
  • fever, if present, is low-grade.

Enteroaggregative E. coli (EAEC):

  • responsible for up to 25% of cases of traveler’s diarrhea,
  • symptoms similar to ETEC-associated illness.

Campylobacter jejuni:

  • commonly associated with diarrhea in developed countries,
  • much more prevalent in developing countries,
  • most of Asia is considered high-risk,
  • symptoms include blood diarrhea and fever.

Salmonella spp.

  • commonly associated with foodborne outbreaks in developed countries,
  • infrequent cause of traveler’s diarrhea.

Shigella spp.

  • common cause of traveler’s diarrhea,
  • low infectious dose required for illness,
  • symptoms include diarrhea (may be bloody), abdominal cramps, and fever.

Vibrio spp.

  • Vibrio parahaemolyticus and non-O-group 1 Vibrio cholerae,
  • associated with eating raw or partially cooked seafood.

Protozoan parasites account for approximately 10% of cases of traveler’s diarrhea. Onset of illness is usually less abrupt than with bacteria-associated traveler’s diarrhea, and symptoms are often persistent.

The most common parasites responsible for traveler’s diarrhea include:

Giardia lamblia:

  • intestinal flagellate,
  • associated with ingestion of contaminated surface water associated with poor sanitary conditions,
  • foodborne outbreaks resulting from contamination of food by infected food-handlers,
  • person-to-person transmission occurs due to poor fecal-oral hygiene,
  • environmentally resistant cyst form shed in feces,
  • incubation period 12-19 days,
  • common symptoms include diarrhea, weakness, weight loss and abdominal pain,
  • less common symptoms of nausea, vomiting, flatulence and fever,
  • illness usually self-limiting, lasting 2-4 weeks.

Cryptosporidium parvum:

  • common intestinal pathogen worldwide,
  • associated with contaminated drinking water and recreational water,
  • average incubation period of 7 days,
  • watery diarrhea most prominent symptom,
  • frequent and copious bowel movement can cause dehydration and weight loss,
  • symptoms include nausea, abdominal cramps, vomiting and mild fever,
  • environmentally resistant oocysts shed in stool for at least 2 weeks following illness.

Cyclospora cayetensis:

  • associated with ingestion of contaminated water and food,
  • incubation period 2-11 days,
  • symptoms include watery diarrhea, fatigue, abdominal cramping, anorexia, weight loss, vomiting, low-grade fever, and nausea,
  • illness may last for weeks with episodes of watery diarrhea alternating with constipation,
  • environmentally resistant oocysts shed in feces for up to 60 days.

Giardia lamblia, Cryptosporidium parvum and Cyclospora cayetensis are endemic parasites in supplies of drinking water throughout the world. All three have been found in most surface waters with concentration related to the level of fecal pollution. The cysts (Giardia) and oocysts (Cryptosporidium and Cyclospora) are resistant to environmental conditions and disinfectants, although boiling water for 10 minutes is sufficient to kill cysts and oocysts. Additionally, relatively low numbers of cysts and oocysts are required for infection to occur (less than 100 cysts/oocysts).

Entamoeba histolytica:

  • developing countries that have poor sanitary conditions,
  • Incubation period usually 1 – 4 weeks,
  • symptoms include loose stools, abdominal pain and cramping,
  • severe form (amoebic dysentery) associated with abdominal pain, bloody stools, and fever,
  • in rare cases, parasite invades the liver and forms an abscess.

Dientamoeba fragilis:

  • protozoan parasite with a world-wide distribution,
  • does not have a protective cyst stage,
  • symptoms, if present, include diarrhea, abdominal pain and cramping, loss of appetite, weight loss, nausea and fatigue,
  • may result as coinfection with pinworm (Enterobius vermicularis).

Although enteric viral infections are responsible for only 5-10% of cases of traveler’s diarrhea, illness does occur and can be fairly debilitating. Nausea and vomiting are the most common symptoms associated with enteric viral infection. Norovirus and rotavirus are responsible for most cases of enteric viral infection.

Considering that 50,000,000 people travel to developing countries each year, and that 30-50% of travelers to high-risk areas become ill during a 1-2 week visit, approximately 50,000 cases of traveler’s diarrhea occur each day. If you are traveling to a high-risk country, take measures to protect yourself and your family from an illness that could not only destroy your vacation, but may also follow you home!

Develop Kids’ Creativity and Teach Biology: Potato Prints and Sea Shells, Ways to Create and Learn

One way to develop children’s artistic talent with lively biology lessons is to teach them how to make potato prints, dried flower pictures and sea shell gifts.

Creating works of art using natural materials like flowers, leaves and sea shells is an art lesson and a biology lesson wrapped in one. Depending on the children’s age and manual skills, one of these methods producing lovely pieces of art work will be suitable for them.

Potato Prints

Making potato prints is the easiest method and can be managed by children as young as five with the suitable help and supervision of an adult, particularly as the use of a sharp knife is involved. All that’s needed are a few fresh, good sized potatoes, a glass of water, a sharp knife, drawing paper and water colors or any other paint which dissolves in water.

First decide what you are going to make. Potato prints can be entire pictures which can be framed and hung for the proud young artist to display. Smaller formats can be turned into greeting cards and bigger sheets can even be used as personalized wrapping paper.

Next, decide on the design according to the object you wish to produce. Then cut the potato in half and again in even-sided wedges, which are to be used as print stamps. Formats can be square, round or half-moon shaped. Moisten the paint sufficiently and dip the potato stamp into the color, then print directly onto the paper. The result is a lovely, mosaic-like pattern.

Admittedly, there’s not much of a biology lesson here, but the kids’ creativity will be stimulated and they learn that natural materials can be put to different uses.

Gifts Decorated With Sea Shells

When by the ocean, take the children for a walk along the beach. They can learn about maritime life by collecting shells. Don’t let them gather broken, too dirty or too tiny shells if you wish to teach them how to decorate gifts by using sea shells. With a bit of help, this artistic activity is also suitable for younger children.

Clean the shells with the help of a steel brush and let them dry thoroughly. Select an item with a smooth surface, like a plain wooden box or an unpainted picture frame. Make sure the surface you wish to apply the shells to is very clean and dry. Turn the shells upside down and erase any irregularities of the rim with a metal or sandpaper file. Remove dust. Apply a thin layer of strong glue and press down firmly.

The shells can be used in their natural state or they can be covered with clear varnish or sprayed with gold or silver spray.

Dried Flower Pictures

Making works of art from dried flowers is a much longer process as the kids are supposed to produce the raw material themselves. Walks in the countryside or a visit to your own flower garden provide children with botanic lessons. For the ultimate purpose of making dried flower pictures it’s best to collect flowers and leaves which preserve well, such as maple leaves, oak leaves, poppy seed flowers, simple roses and pansies.

The drying process involves spreading out the collected flowers carefully so as not to damage the petals, placing them between two sheets of blotting paper and piling a few heavy books on top. Once the flowers and leaves are dry and pressed, they must be carefully removed with the help of pincers, arranged in the desired pattern and perhaps be cut to size and shape with sharp nail scissors.

Glue is applied to the surface, cardboard or silk being the most suitable, and pressed down firmly. Again, the finished art work is best preserved framed and under glass or else laminated.

Kids will be very proud to have created pieces of art, letting their fantasy and imagination guide them and, at the same time and with no effort, will have learned about botany and sea life.

Anthrax in Cattle: The Risk to Humans

There are 3 main types of anthrax – cutaneous, gastrointestinal and respiratory. All three types of infection can occur in animals and humans. Spores are an important factor in transmitting infection, and animals usually become infected through grazing in areas where large numbers of spores are present in the surface of the soil (link to anthrax and cattle). Therefore natural infection in humans is not likely to occur unless they are in contact with infected animals or animal products.

Infection in animals is usually gastrointestinal, and the most likely route of infection in grazing animals is through ingestion of spores during dry periods following flooding. Spores are brought to the surface during periods of heavy rainfall and remain there and become concentrated during dry spells. Ingestion alone does not necessarily result in infection – the spores require a lesion of some sort to gain entry into the tissues. Gastrointetinal lesions may occur when grazing on dry, spiky, gritty grass that grows close to the soil – infection occurs where spores have also been deposited on the soil.

Grazing animals may also become infected through inhalation of spore-laden dust (pulmonary anthrax), although infection by this route is much less common than through ingestion. Animals that feed on the carcasses of dead animals can also become infected during outbreaks in grazing animals.

Humans become infected through contact with infected animals or animal products such as carcasses, hides, wool, hair and bone meal. Therefore, in areas where infection in livestock is uncommon, human infection is also rare.

The World Health Organization (WHO) reports higher incidence of infection in certain areas of Canada such as the MacKenzie Bison Range, North West Territory and Wood Buffalo National Park in northern Alberta, with sporadic outbreaks occurring in southern Alberta and Saskatchewan. In the U.S., sporadic cases occur in South Dakota, Nebraska and Oklahoma, with more persistent outbreaks in western Texas. In other areas of the world outbreaks occur more consistently – Central and South America, Mexico, South Africa, Middle East, Soviet Union, southern India, and south-east Asian countries (Vietnam, Cambodia, western China, Thailand).

The most common form of natural human infection is cutaneous anthrax, accounting for at least 95% of cases world-wide. Cutaneous anthrax is readily treated with penicillin and a number of other antibiotics. Without treatment, 10-20% of cutaneous infections may be life-threatening. Contact with the vegetative form of the bacteria in the fluids and tissues of sick or dying animals, or with spores in dead carcasses, meats, hides, hair, wool or bone does not guarantee infection. Infection requires a skin lesion (cut, scrape, etc.) in order to gain entry to the tissues. In 2-3 days (may occur as early as 9 hours or as long after as 7 days) a pimple-like red elevated area appears, followed 1-2 days later by a ring of blister-like, watery fluid-filled vesicles with swelling in the surrounding area. By 5-7 days, an ulcer forms (eschar) (see photo). By approximately 10 days, the eschar begins to heal and may take up to 6 weeks to resolve. Treatment at this stage does not speed healing. Without treatment a small number of cases may develop systemic infection.

Gastrointestinal and pulmonary anthrax have much higher mortality rates than cutaneous anthrax, often because they are more likely to go unrecognized and untreated. Treatment in the early stages of either infection is very effective; however, the disease progresses rapidly, and in the latter stages of infection treatment is often ineffective.

Gastrointestinal infection may occur following ingestion of raw or improperly cooked meat from sick or dead animals and symptoms are similar to other food-borne illnesses –

nausea, vomiting, fever, abdominal pain. Cases may be mild or severe – in severe cases the mortality rate is approximately 50% even with treatment.

Pulmonary anthrax is even more likely to be misdiagnosed as the initial stage of infection involves flu-like symptoms – mild fever, fatigue and malaise lasting one to several days. Without treatment at this stage, infection progresses rapidly to difficulty breathing, disorientation, toxemia and death. Naturally acquired pulmonary anthrax in humans is extremely rare.

Sea Turtles of Sipadan Island

A visitor to Sipadan Island (or Pulau Sipadan as it is locally known) is sure to see an abundance of marine life including whirling schools of barracuda, roaming sharks, and of course, plenty of sea turtles. Sipadan dive operators often boast that turtle sitings are guaranteed on their tours, and those boasts are not often wrong. Yet sea turtle populations throughout Malaysia continue to struggle, meaning Sipadan’s turtles must be studied and enjoyed with care.

Turtle Species of Pulau Sipadan

Malaysia is home to four species of turtle according to the WWF-Malaysia website (“What we do>Species>Turtles”). These include the Leatherback, Olive ridley, and Hawksbill turtles. The most abundant species however is the Green turtle – a creature which is actually black brown or greenish yellow in color. Regardless of its color this magnificent animal can grow to be four feet long and is quite an exciting find when visiting Sipadan dive sites.

It may be hard to recognize that all of Malaysia’s turtle species are endangered when visiting Sipadan. According to SCUBA diver and travel writer Jack Jackson in his book Diving with Giants as many as 30 turtles can be seen on a single dive in the month of August. This is peak egg laying season but each species of turtle uses Pulau Sipadan as a nesting site year round.

Sipadan Dive Sites and the Turtle Cavern

Sipadan Island is surrounded by beautiful dive sites most of which are home to large sea turtles. According to the online diver’s resource Asia Dive Site under its “Malaysia: Sipadan” entry, dive sites such as Coral Gardens, South Point, North Point, and Turtle Patch are all excellent places to go for turtle sitings. However, Sipadan’s most famous dive site is probably Turtle Cavern. A dark labyrinth of caves, Turtle Cavern was once thought to be the place where Sipadan turtles go to die. The cavern’s floor is littered with turtle skeletons and carcasses.

Unfortunately, the truth behind the cavern is quite chilling. According to Jack Jackson in Diving with Sharks and Other Adventure Dives, turtles use caves to rest in, but some turtles venture too far into the tunnels and, no longer able to see the light at the entrance become lost. Unable to find their way out, the turtles cannot surface to breathe, and thus drown within the cave system.

Visitors hoping to dive Sipadan will find a unique site at Turtle Cavern. However divers should approach the cave with caution so they do not meet the same fate as the unfortunate lost turtles.

Sea Turtle Conservation on Sipadan Island

Unfortunately, caves aren’t the greatest threats to turtles in Malaysia. Humans hunting turtles, developing resorts on their nesting sites, and accidentally catching them in fishing nets has driven all four species of Malaysia turtle onto the endangered species list. Recognizing this, the Malaysian government has taken steps to conserve turtles near Sipadan.

Asia Dive Site writes that, Sipadan has been declared a national park. All resorts that were on the island have left and the number of visitors to the island are restricted. These decisions seem to have helped Sipadan’s marine life writes the Borneo Post in “Marine Life Galore at Sipadan Island Marine Park”. The article writes how the Sipadan Island Marine Park Scientific Expedition found turtle populations increased since 2005 with 50-60 turtles seen in one day near their feeding area.

Neuroscience and the Neuronal Correlates of Consciousness

Neuroscience and the Brain

Even the most enthusiastic neuroscientist will concede that the human brain is not much to look at: a 1.5kg cauliflower of grey, spongy matter. But despite their modest outward appearance, our brains are the most complex objects known to man, and still represent the greatest problem in biology: how the timed firing of electrical signals from neurons, along with glial cells and neurotransmitters, can give rise to something as remarkably abstract as our own consciousness.

With recent advances in the field of neuroscience, the way we think about the way we think is changing, and the quest for the physical basis of consciousness promises to be a voyage of discovery as fascinating as the quest for the structure of DNA in the early 1950s. But what exactly are the problems facing neuroscientists, and how are these being solved today?

Defining Consciousness and Awareness

Perhaps the first issue is in defining consciousness itself. As human beings, we experience the world. When light of a certain wavelength hits the cone photoreceptors of our retina, we experience the sensation of seeing “red”, for instance, and we have feelings that correspond to this experience.

We are also probably not the only animals who experience the world in this way. Experimenting (humanely) with chimpanzees and dolphins has demonstrated that they are capable of complex, abstract tasks such as recognising themselves in mirrors (Gallup, 1970) and planning future actions (BBC), activities which should be impossible without some form of consciousness, or inner mental life.

Even the humble fruitfly has demonstrated that it is capable of complex behaviours involving choice (Heisenberg and Wolf, 1984). As such, Descarte’s idea of there being a “threshold of consciousness” over which only humanity has stepped has begun to sound as outdated as the concept of a geocentric universe.

Are Computers Conscious?

However, a neat sliding scale of consciousness also has its faults. Everyone has experienced what happens when a computer finds a fault in its hardware: you will likely receive a cryptic error message, or simply the “blue screen of death” as the damaged system struggles to function. But the idea that computers sense this line of code as analogous to pain, or that they experience the world on any level at all, can be discarded fairly quickly.

That is not to say that this suggestion does not have its proponents. Some scientists, like David Chalmers of the University of Arizona, postulate that all systems capable of processing information, even digital systems, are conscious in some sense, if only on a rudimentary level. Chalmers does concede, however, that it would probably not feel like much “to be a thermostat” (Koch & Krick).

Were this theory correct, it would suggest that our spinal columns, for instance, along with many parts of our brain and even the 100 million or so neurons found in the intestinal wall, could themselves be conscious. After all, they, too, process enormous amounts of information every second. If they are, of course, they are certainly not telling us about it!

Studying the Brain

One problem for scientists is that in-depth study of the brain is necessarily an invasive and life-threatening procedure. Much has been learnt from studies involving electrodes measuring the brain’s electrical field from outside the skull, but this is as problematic as trying to learn about the structure of the ocean by studying its waves.

As such, a vast majority of recent developments in the science of our own minds comes from what happens when they go wrong. Patients suffering massive epileptic seizures must undergo complicated surgery to have electrodes placed inside their brain in order to locate the troublesome tissue causing their seizures. This gives scientists a unique opportunity to study the way the brain works, and in particular how its workings give rise to consciousness.

The Clinton Neuron

One remarkable discovery has involved a specific neuron found in a seizure patient that fires whenever the subject sees a picture of former US president Bill Clinton. The patient was shown photographs of other white-haired men, other former presidents and hundreds of random control pictures, none of which elicited a response. Every time Mr. Clinton entered the subject’s field of view, the electrical readings from this single neuron spiked.

The implications of this are enormous, since it places the firing of neurons right at the start of the chain of mechanisms that create consciousness. When this neuron and the possibly hundreds of other “backup” duplicates fire, they somehow start a series of events that results in the patient recognising a face. But the question remains: how does this binary system of neurons either firing or remaining dormant create the almost infinite intricacies of our minds?

How Do Bacteria Make People Sick?: Bacterial Pathnogenicity, Virulence Factors and Infectious Disease

In order to cause disease, potentially harmful bacteria must first enter the body, usually through breaks in the skin, penetrating the mucous membrane or colonizing the gastrointestinal (GI) tract. This is considered infection, when bacteria breech the first line defenses of the body.

Bacterial disease starts with infection, but infection does not always result in disease. Many bacteria are beneficial. And even when pathogens infect the body, the immune system may be able to eliminate the infection before symptoms of disease occur.

Bacterial Pathogenicity and Virulence

To cause disease, bacteria must be present in sufficient numbers. But what is it about bacteria that make an infected person ill? Disease is not merely caused by the presence of microbes.

Pathogenicity (path-o-jen-ISS-ity) refers to a microbe’s ability to cause disease, and some microbes are more pathogenic—better able to cause disease—than others. The degree of a microbe’s pathogenicity is considered its “virulence.” For example, highly virulent bacteria frequently cause disease, whereas less virulent bacteria may only cause disease when present in large numbers or within hosts that have weakened immune systems.

Many pathogenic, or disease-causing bacteria have special weaponry, traits that enable them to infect and damage host tissue. These disease-causing traits are called “virulence factors”. The following sections describe different types of virulence factors.

Adhesion Factors, Glycocalyces and Biofilms

Once bacteria get into the body, they must be able to stick to the host’s cells in order to increase in number. Bacteria that are able to stick to host cells have special structures or chemicals, collectively called adhesion factors. These adhesins are found on bacterial cell extensions, such as fimbriae and flagella, and also on glycocalyces, a sticky layer surrounding some bacterial cells that enable bacteria to stick to surfaces and to each other in biofilms. For example, the inside of the mouth and teeth are covered with a sticky bacterial biofilm, particularly in the morning, before brushing, because bacteria have been multiplying in the mouth throughout the night.

Bacterial Extracellular Enzymes

Some pathogenic bacteria are able to produce and secrete enzymes that compromise cell structure of the host and enable the bacteria to work their way further into the body.

Bacterial Toxins

Bacteria may also produce toxins that cause damage to host cells either directly, by destroying tissue, or indirectly, by triggering an intense or prolonged host immune response. Bacterial toxins fall into two general categories based on their position relative to the cell that produces them; exotoxins, which are secreted by bacteria, and endotoxins, such as lipid-A, which are part of the Gram-negative bacterial cell.

Evading Host Immune System

The human immune system has special white blood cells called phagocytes, which search out, engulf and digest invading pathogens. The sooner a pathogen can be eliminated from the body, the less damage it will have the opportunity to cause. However, bacteria have developed means of evading phagocytes.

The bacterial capsule, a type of glycocalyx, can help a bacterium hide from the immune system. This coating is often made of chemicals that are found in the human body, and that don’t trigger an immune response.

Other bacteria produce chemicals that prevent them from being digested once engulfed by a phagocytic white blood cell, allowing the bacteria to live and reproduce inside the host cells designed to eliminate them. Other antiphagocytic chemicals can prevent bacteria from being engulfed by white blood cell, or can even destroy white blood cells.