How To Streak a Bacterial Culture

How To Streak a Bacterial Culture Bacterial culture streaking allows bacteria to reproduce on a culture medium in a controlled environment. The process involves spreading bacteria across an agar plate and allowing them to incubate at a certain temperature for a period of time. Bacterial streaking can be used to identify and isolate pure bacterial colonies from a mixed population. Microbiologists use bacterial and other microbial culture streaking methods to identify microorganisms and to diagnose infection. What You Need: Culture plate with microorganismsInoculating loop or sterile toothpicksAgar platesBunsen burner or another flame producing instrumentGlovesTape Heres How: While wearing gloves, sterilize an inoculating loop by placing it at an angle over a flame. The loop should turn orange before you remove it from the flame. A sterile toothpick may be substituted for the inoculating loop. Do not place toothpicks over a flame.Remove the lid from a culture plate containing the desired microorganism.Cool the inoculating loop by stabbing it into the agar in a spot that does not contain a bacterial colony.Pick a colony and scrape off a little of the bacteria using the loop. Be sure to close the lid.Using a new agar plate, lift the lid just enough to insert the loop.Streak the loop containing the bacteria at the top end of the agar plate moving in a zig-zag horizontal pattern until 1/3 of the plate is covered.Sterilize the loop again in the flame and cool it at the edge of the agar away from the bacteria in the plate that you just streaked.Rotate the plate about 60 degrees and spread the bacteria from the end of the first streak into a second area using th e same motion in step 6. Sterilize the loop again using the procedure in step 7.Rotate the plate about 60 degrees and spread the bacteria from the end of the second streak into a new area in the same pattern.Sterilize the loop again.Replace the lid and secure with tape. Invert the plate and incubate overnight at 37 degrees Celsius (98.6 degrees Fahrenheit).You should see bacterial cells growing along the streaks and in isolated areas. Tips: When sterilizing the inoculating loop, make sure that the entire loop turns orange before using on the agar plates.When streaking the agar with the loop, be sure to keep the loop horizontal and only streak the surface of the agar.If using sterile toothpicks, use a new toothpick when performing each new streak. Throw all used toothpicks away. Safety: When growing bacterial colonies, you will be dealing with millions of bacteria. It is important that you follow all lab safety rules. Precautions should be taken to ensure that you dont inhale, ingest, or allow these germs to touch your skin. Bacterial plates should be kept closed and secured with tape while incubating. Any unwanted bacterial plates should be disposed of properly by placing them in an autoclave to kill the bacteria before discarding them. Household bleach may also be poured over the bacterial colonies to destroy them.

Custom Essay A No-Cost Sample About Pandas Created by Top Writers

Custom Essay A No-Cost Sample About Pandas Created by Top Writers Descriptive Essay Example about Pandas How could anyone not be charmed by a Giant Panda? The black-and-white bears are a national treasure of China, whose bamboo forests are their natural habitat, and universally recognized as the epitome of cute: A panda is nothing more or less than a chubby, fluffy ball of gentleness, and if we didn’t know they were a real animal from an identifiable part of the world, we would assume they came from the same place where rainbows and unicorns are made. In ancient China, warring armies even used to raise flags emblazoned with images of pandas when they wanted to stop fighting and discuss their problems peacefully. Private Writing offers professional writing assistance with any kind of writing assignments in any field of knowledge alongside with the individual approach to every customer. Our top-notch customer support is ready to help you 24/7. Place an order and enjoy the result. It seems, however, that Mother Nature may have given the Giant Panda its heartwarming appearance as a consolation prize to partly make up for all the other traits that make the panda kind of an evolutionary failure. The Giant Panda is indeed a peaceful creature, but that is because it simply does not have the energy not to be. Unlike other bears, which are omnivorous, the panda’s diet consists solely of bamboo. A single panda requires an area of about four square kilometers of bamboo to have a sufficient supply of food, and it must spend 14 to 16 hours of each day eating that food in order to survive. The panda has to spend so much of its time eating because it has a poor digestive system. The panda only uses about 30% of the nutrients from its diet; by comparison, other herbivores such as deer use about 80%. The panda’s diet does give it one dubious talent: Pooping. Because most of what it eats passes through the panda’s system undigested, an adult panda produces an astonishing amount of â€Å"number two† – as much as 62 kilograms per day. The Giant Panda’s inability to use its food efficiently also prevents it from hibernating; the panda simply cannot eat enough to build up the fat reserves necessary to allow it to slumber through the winter like a â€Å"normal† bear. The diet also is responsible, some scientists believe, for the panda’s unusual reproductive pattern. Female pandas ovulate just one a year and are only fertile for two or three days. Because pandas must individually maintain a large area of the bamboo forest for their own food needs, encounters between pandas in the wild are relatively rare, and that includes opportunities for mating. If mating is successful, gestation takes from four to eight months; the wide time range is due to the female panda’s body delaying implantation of the fertilized egg until there is enough nutrition to support it. Then once the panda cub is born, it has a fifty-fifty chance of surviving to adulthood; panda cubs are easy prey for a number of predators, but more often than not are killed by being accidentally crushed by their own mothers. While the Giant Panda has been seriously threatened by human activity such as poaching – which is treated as a heinous crime in China, punishable by a long prison sentence or even the death penalty – and destruction of its natural habitat, the panda’s characteristics that naturally seem to work against its survival have led some scientists to conclude it is a â€Å"remnant species†: One that is naturally becoming extinct on its own. In that sense, the fact that pandas are just so darned adorable may be a clever evolutionary advantage – unable to survive in the wild, the Giant Panda is equipped with a look and a personality that has proved irresistible to the one species with the ability to overcome nature for the panda’s ultimate benefit. We hope that this descriptive essay sample provided above will help you to write a brilliant descriptive essay. If you dont have time to write a descriptive essay on your own, feel free to contact our essay writers or place an order.