Bearing Light On Gene Expression : Streamlining Light Controllable Escherichia Coli

To understand the diverse causes of RP, a basic understanding of visual perception is required. Phototransduction (conversion of light to electrical signals) occurs first, which is initiated by two types of photoreceptors: rods and cones. These two types vary in their function as rods are primarily responsible for night vision and lack sensitivity to color while cones function in color vision. Light contacts these photoreceptors, and isomerizes a retinaldehydechromophore (retinal) which is bound to varying types of opsin proteins corresponding in their reactivity to different wavelengths of light. Upon absorption of a photon of light, the chromophore 11-cis-retinal is isomerized to the all-trans confirmation, which subsequently causes a series of molecular interactions which ultimately result in the electrical response of the photoreceptors (Vugler 2010). As 11-cis-retinal is required to absorb photons of light, this compound must be regenerated, a function that is performed with the aid of nearby cells of the retinal pigment epithelium

Furthermore, there are aquatic organisms such as the mantis shrimp that has an estimated 12-16 photoreceptor cells. In the presence of the 750 nm wavelength of light that humans cone cells aren’t sensitive enough to signal an observation, the mantis shrimps red cone cells are sensitive to this wavelength of light and can absorb the wavelengths to send a response to their brain. In the presence of UV-B (290-320 nm) wavelengths, humans blue cone cells aren’t sensitive enough or able to absorb enough of the light to signal a response to their brain. Whereas the Mantis Shrimp has various photo receptors that are sensitive to these

Raimondo, J.V., Kay, L., Ellender, T.J., Akerman, C.J. (2012) Optogenetic silencing strategies differ in their

When the photoreceptors are stimulated they transmit impulses to the bipolar cells that project to the ganglion cells of retina.

The authors were trying to achieve a goal that they describe as a major goal in the field of neuroscience. They were looking for some method of reporting electrical activity in neuronal populations, specifically optical reporting. They developed a voltage sensor that they named Accelerated Sensor of Action Potentials 1 or ASAP1. This allows for GFP to be inserted into an extracellular loop of a voltage-sensing domain (VSD) and making fluorescence responsive to membrane potentials. They were looking for ASAP1 to detect a broad spectrum of membrane potentials, ranging from subthreshold to rapid trains of action potentials. For this to be the case they had to have the appropriate brightness, dynamic range and kinetics.

More than forty percent of the mice tested gained the ability to see light clearly. This was a new medical advancement for the science community as no one has ever before been successful in transplanting stem cells that have the ability to sense light. Retinal degeneration is extremely complex to treat until now. Cells need to have the ability to make connections with the host’s nervous system and send signals to the brain. Regardless, many unsolved answers exist. Researchers are still trying to find a way to increase the number of connections between a degenerated retina and the transplant. This would allow the hosts to not only see light but large-scale figures and movement. This is extremely important as retinal degeneration that affects approximately around 170 million people worldwide can led to total blindness. Nevertheless, this advancement comes with many unanswered questions. Researchers are concerned whether this treatment could actually be applied to humans as many risk factors exist. The experiments do not provide information on recovery time in humans nor how the transplanted retinas would respond to the same procedure. Moreover, Scientists contend whether human eyes have different environments from mice. The only way researchers could test human retinal transplants would be from human conducted trails which remain a controversial

Two experiments were conducted to examined the movement of the planarians toward different light intensities. There are four light intensities, including ambient, high (19 cm), medium (29 cm), and low (43 cm). The hypothesis of the two experiment is that as the light intensity increases, the planarians’ speed increases as well. Generally, planarian brain perceives information from multiple external signals that receive from sensory neurons. The brain will then integrate the information and produce appropriate behaviors in response, such as thermotaxis, phototaxis, or chemotaxis (Inoue, 2015). When planarians were exposed to the ambient light, the brain sent out phototaxis. When the motor neurons received the signal, the planarians would gradually move to different place with dimmer lighting. However, when the intensity of light suddenly changed from ambient lighting to high intensity (19 cm), the planarians immediately changed the behavior and moved much faster which moving from 44.96 sec to 28.04 sec (Table 3) to go from one end to another end. This data indicates that planarian brain send out the same behavior but stronger signals which caused the planarian to move faster. In this case, the neural nervous system received the strong signals from the sensory neuron which generated the strong intensity in graded potential and high frequency in action potential (Campbell, 2010, 1097). The

The association between Arginine vasopressin and visual processing is one of the least studied regions when it comes to AVP and sensory integration links although many visual inputs enter brain regions which are comprised of vasopressin receptors. One of the few studies that research this link includes an exploration of visual opsin sequences in diverse vertebrate animals. The researchers claimed that the visual opsins and AVP receptors are located together in the same genomic region(130). For instance, in chickens, it was claimed that a visual opsin was sharing a genomic region with AVT in the neurons. Nonetheless, even though the other functions of opsins besides the visual ones are still unknown, a study performed in Japan hypothesize that the pigments are permitting the neurons to react to light and contribute with coordination of behavior (Bester et al. 2015).

Genetic engineering is the deliberate modification of the characteristics of an organism by manipulating its deoxyribonucleic acid (DNA). Bacteria possess plasmids which can be used as vectors for bacterial transformation. The plasmids can be altered to include donor DNA thus altering the physiological or physical characteristics of the bacterium. Escherichia coli have been found to be the most effective bacterium in genetic transformation and heterologous expression of human genes or proteins. It was hypothesised that Escherichia coli HB101 K12 could be transformed with a pGLO plasmid to express the genes encoded for green fluorescent protein (GFP), the bla gene for ampicillin resistance and the araC gene a regulatory protein in facilitating transcription and therefore the transformation efficiency for this bacteria could be calculated. Bacillus megaterium, E.coli B strain, Erwinia carotovora, Pseudomonas fluorescens, Staphylococcus epidermidis and Streptococcus lactis will also be subjected to transformation with the pGLO plasmid to collect transformation efficiency data for comparison against Escherichia coli HB101 K12. Escherichia coli HB101 K12 were found to have been successfully transformed with a transformation efficiency falling within the transformation protocol of 8.0 x 102 and 7.0 x 103. The incidence of Escherichia coli HB101 K12 on the LB/amp and LB/amp/ara pGLO+ plates indicated that the bacterial colonies present showed resistance to the ampicillin

The therapeutic properties of light have a long history. The ancient Indians discovered, in 1,000 BCE that light therapy, in addition to psoralens, a plant compound, could cure vitiligo (Barr, H. et al., 2002). In the early 20th century, Niels Finsen’s and his wife’s treatment of lupus vulgaris with ultra-violet light notably earned them the Nobel Price (Barr, H. et al., 2002). A more modern application of light’s theraputic properties is photodynamic therapy. Photodynamic therapy destroys tumours through the use of a photosensitizer, oxygen, and light in a wavelength specific to the photosensitizer (Brown & Ibbotson, 2009, p. 251; Barr, Kendall, Reyes-Goddard & Stone, 2002, p. 136). First, the photosensitizer is administered (Brown & Ibbotson,

6- Outer Plexiform Layer :where photoreceptor cells form connections with the bipolar and horizontal cells of the inner nuclear layers.

Planarians of the Phylum Platyhelminthes are the simplest multicellular organisms and have many homologous systems to humans. Structurally, the invertebrate has a rudimentary nervous system with a cerebral ganglia connected to two nerve cords interlocked by transversal nerves that extend throughout its body. Chemically, planarians produce serotonin, dopamine, Gamma-aminobutyric acid (GABA), and have acetylchlorine (ACH) receptors and Glutamate Carboxypetidase II (GCII) inhibitors in their nervous system (12, 18, 19). Photo receptive ocelli with a negative phototaxis serve for visual aids, and explain the reason for their regression from light. While no respiratory, circulatory, or skeletal systems are present, carbon dioxide and oxygen are diffused into the organism’s cells

Bioluminescence has been utilized by a variety of organisms for thousands of years. Within this time period, bioluminescence has been through a series of evolution making it unique to the organism that utilize them. Although the specific biochemical components and pathways tend to be varied among species, most bioluminescent processes involves a substrate and an enzyme known as luciferin and luciferase. The substrate Luciferin is a compound that tends to undergo through oxidation and is the source of light of most bioluminescent organism. Luciferase on the other hand is an enzyme that catalyzes luciferin. In most species luciferin and luciferase are housed in the light producing components of the organism. These molecules are mixed together along

Hexapede organism informs its muscoskeletal system to carry out a movement or physical action by transporting electronic signals that are directed via the neurons of the brain to the vision of

This article discusses optogenetic inhibition, which is the use of light-activated ion pumps to enable transient activity suppression of genetically targeted neurons by pulses of light. The created silencer ‘Jaws’ results in red light-induced photocurrents three times those of earlier silencers. This red-shifted variant can help solve known issues associated with implants, as it is a non-invasive method. Similar to previously mentioned papers focusing optogenetic excitation, this article will be used to provide more information about ChR variants and provides the basic knowledge to understand neuronal silencing as it is used in studies regarding optogenetics and Parkinson’s disease.