Speckled kingsnake (Lampropeltis getula holbrooki)

On a recent trip to Mississippi, I stopped to look at a freshly killed roadkill snake (I didn’t hit it). It turns out it was a speckled kingsnake (Lampropeltis getula holbrooki). The snake is black with flecks of yellow through and a yellow belly. They can reach up to 132 cm long (51 inches).  The one I found looked almost green. They are also called the salt-and-pepper snake for their unique coloration and commonly kept as pets due to their beauty. Apparently, you can buy one online for 60 dollars. However, they often bite and it’s unclear if their populations in the wild are steady. They will also rattle their tail when threatened to mimic a rattlesnake, and spray musk from their scent gland. This musk is actually used to let other snakes in the area know that there is danger.

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It’s one of the eight subspecies of the eastern kingsnake (Lampropeltis getula). Kingsnakes are a type of racer snake, and kill their prey via constriction which you would be able to guess if you looked at their heads and how small their jaws are. They are found throughout the united states and even in Baja Mexico. They prefer to live in grassland, swamps, and near streams. They have really varied diets and will even eat other snakes. They have evolved to clamp down on the jaws of other snakes to avoid being bitten by a venomous one but even if they are bitten they are immune to the venom as well. Because they eat and kill venomous snakes people tend to really like kingsnakes and even state they are protecting the neighborhood. Snakes also help to reduce the populations of rodents and other “nuisance” animals.

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Interestingly, the Alabama Department of conservation and natural resources says there is a high conservation concern for the snake as the past 30 years have led to rapid declines in populations for unknown reasons. It is suspected that red ant prey on the young and eggs of the snakes and contributed to their decline. Declines are also thought to be related to the logging of hardwood trees in the area. The Mississippi deparmtent of wildlife, fisheries, and parks did not have any information on the snake. Kingsnakes are also eaten by alligators, striped skunks, and possums.

Water privatization

Water privatization, in principle, is great. The idea is that corporations have the financial resources that governments do not to provide the people with clean water. In addition, they can afford the big upfront costs of creating a water system. However, when put into practice privatization fails. A water system requires huge and ongoing infrastructure investments. Corporations have cut corners on these which leads to a shortage of access. Privatization, in fact, has a 34 percent failure rate. Because the system costs so many people often are forced to overpay for their water.

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Source: food and water watch

The film Flow documented people in African who could not afford the privatized water. Instead, they drank from the river which resulted in people dying from waterborne illnesses. The companies, when questioned, insisted that the people could afford the water. In addition, the companies also cemented old wells and prevented the local people from using their old, and free methods of accessing clean fresh water. The only upside to privatization is that it is easy to solve; don’t allow privatization to happen. Poor nations will need aid though, to help ensure their people have clean fresh water, but this is part of a continuing effort, as there are many charities focused solely on this issue.

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Ocotillo (Fouquieria splendens)

Ocotillo (Fouquieria splendens) is a desert plant that is found in the Sonoran Desert and Chihuahuan Deserts of North America. Although there are other ocotillo species that are found further south. The plant is made up of long thin individual stacks and when it is in bloom those stacks are tipped with a cone of bright red flowers. In fact, they are named for these flowers as ocotillo is Spanish for little torch. This flowering actually is timed to happen when the hummingbirds are migrating through the desert.

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PCR and Gel Electrophoresis

I used to teach a genetics lab and thought I would share what I taught my students. Before running polymerase chain reactions (or PCR), to make copies of your sample DNA, it is important to run a gel with your DNA extraction to see if the extraction worked. To run a gel, the DNA sample is loaded into wells on one side of a gel. An electrical current is used to separate out the DNA to analyze it. If your DNA extraction did not work it is a waste of money to run PCR on the sample. This gel is run in buffer TBE. TBE contains tris which raises the pH to 9, a boric acid which lowers the pH to optimizes it for the target enzymes, and EDTA which chelates metal ions and those stops DNeasy activity, which is the enzyme used for DNA extraction. The molecules in the gel separate based on charge, size, and shape. Personally, I like to use 1% agarose gel with TBE at 120 volts for 30 minutes.

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But what is agarose? It’s a seaweed polysaccharide that allows the gel to thicken. The more agarose you use the thicker the gel and the longer it will take your DNA sample to run through the gel. If you need to separate out really small fragments you would need a really thick gel but since we are looking to see how well the DNA extraction worked we can use a thin gel. You should also stain the DNA sample before putting the sample in the gel. If you don’t stain the sample you wouldn’t be able to see where your sample goes in the gel and run the risk if running your sample off of the gel. Gels also often have glyercide in them that binds to the DNA and makes it heavier so when you load your DNA into the well on the gel it is less likely that the DNA floats away. It another well a ladder is also typically used. In this case, we used a 1000 kb base pair ladder. A ladder is DNA fragments that are cut at known lengths. This allows it to act as a ruler for your other samples.

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Queen parrotfish (Scarus vetula)

The male queen parrotfish (Scarus vetula) is one of the most striking fish in the Carribean and happens to be my 2nd favorite fish. Females are a drab blue brown color while males are green-blue. This is an example of sexual dimorphism. Both sexes have plate-like beaks which give them the name parrotfish. They use these beaks to break off coral covered in algae. they then chew that mass and excrete the matter that isn’t algae. This process creates sand from the coral they ingest and is actually a major way in which sand is produced. This grazing also opens up space for coral to grow back in areas overtaken by algae. In areas without parrotfish reefs have been shown to shrink because coral can’t out-compete algae. They also feed on sponges and other creatures that may be attached to the reef. The fish is also known by the names blownose, blue chub, blueman, blue parrotfish, Joblin crow parrot, moontail, Okra peji, and slimy head. They are native to reefs in the Carribean, and thus also restricted to shallow water. 1622-parrotfish_0

The fish breed throughout the year but typically restrict breeding to mornings. The fish exercise harem polygyny, which means that one male mates with a harem of females. They school in groups with one male and 3-4 females. However, the fish are also protogynous hermaphrodite which means that they can change their sex from female to male. In fact, all queen parrotfish are born as females. As they mature the largest in the school becomes male. The male that mates with the females is called a supermale and is identifiable by his bright coloration. The male chases the females and they swim in tighter and tighter circles until they release their gametes and the eggs are fertilized through external fertilization.

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A female queen parrotfish (Scarus vetula)

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The genetics of viruses

Viruses are infectious particles made of nucleic acid encased in a protective protein coat and, sometimes, a membranous envelope. The genome of viruses may consist of double-stranded DNA, single-stranded DNA, double-stranded RNA, or single-stranded RNA, depending on the kind of virus. The viral genome is usually organized as a single linear or circular molecule of nucleic acid. The genome is encased in a protein shell called a capsid which is derived from the host cell. The most complex capsids are found in viruses that infect bacteria, called bacteriophages or phages. A virus has a genome but can reproduce only within a host cell. Dr. Beijerinck used the sap from one generation of infected plants to infect the second generation of plants that could, in turn, infect future generations. Dr. Beijerinck determined that the pathogen could reproduce only in the host, could not be cultivated on nutrient media, and was not killed by alcohol which generally kills bacteria.

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An isolated virus is unable to reproduce—or do anything else, except infect an appropriate host. This is because viruses lack the enzymes for metabolism and the ribosomes for protein synthesis. Each type of virus can infect and parasitize only a limited range of host cells, called its host range. Viruses identify host cells by a “lock and key” fit between proteins on the outside of the virus and specific receptor molecules on the host’s surface. Most viruses of eukaryotes attack specific tissues. Most DNA viruses use the DNA polymerases of the host cell to synthesize new genomes along the templates provided by the viral DNA.

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Ecosystem roles in tropical rainforests

Primary producers in all of these ecosystems vary. In rainforests, the primary producers include trees, shrubs, and epiphytes. An epiphyte is a plant that grows on another plant but it not directly parasitic. In mangroves, they are epiphyte and mangroves. The term mangrove describes how the trees live, it is not a taxonomic term. It simply describes a tree that lives in salt water. In a reef, the primary producers are corals, seagrass, and macroalgae (seaweed). Interestingly corals are also predators of the reef. The algae they are in a symbiotic relationship (zooxanthellae) with undergoes photosynthesis during the day. At night they hunt small organisms in the water and spear them with tiny barbs.

 

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A view of Guatemala primary producers. Captured by Lauren Schramm

 

Herbivores (or primary consumers) in the mangroves, rainforest, and reefs all vary. In rainforests, these include birds, monkeys, agouti, tapir, butterflies, and sloths. In the mangroves there are fewer herbivores, these include mollusks and crabs. In the reef system, most organisms are herbivores. These include coral, smaller fish, sponges, plankton, and mollusks.

 

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An Agouti (Dasyprocta punctata )

 

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