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Sean Nash

Learning in Plants: Lessons from Mimosa pudica - 4 views

  • there is a lack of observational data on the behavior of plants
  • Observational research allows the researcher to establish baseline activity and response levels of the subject
  • Perhaps the first study of learning in plants was a habituation experiment reported by Pfeffer (1873) using the sensitive plant Mimosa. In this experiment, repeated mechanical stimulation of leaflets led to a decrease in sensitivity
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  • the question naturally arises as to whether Mimosa can discriminate between stimuli. This was answered in the affirmative by Holmes and Gruenberg (1965) whose experimental design included a drop of water and finger touch as stimuli
  • the results suggest that Mimosa can discriminate between stimuli
  • Thomas performed an experiment on classical conditioning in Mimosa that took advantage of the finding that, under field conditions, the leaflets of Mimosa slowly drop as dusk approaches and slowly rise at dawn (personal communication). In the experiment, the CS was turning on the light in the growth chamber and the US was touching selected leaflets. Thomas found that leaflets in the paired condition showed conditioning compared to a light only or alternating stimulation condition. This finding should be replicated with controls for pseudoconditioning.
  • Given the importance of the Gagliano et al. (2014) experiment and the failure to replicate some previous experimental results it is critical that the Gagliano et al. (2014) results be repeated by an independent laboratory.
  • In addition to Mimosa, habituation has been found in the carnivorous plant Drosera (sundew
  • Applewhite (1975) cites an experiment by Darwin reportedly showing habituation in the passion flower (Passiflora gracilis). During this experiment, when Darwin mechanically stimulated the passion flower tendrils, the tendrils no longer responded after 54 h of training.
  • Abramson et al. (2002) investigated the use of bioelectrical potentials as a method to explore plant behavior.
  • In an interesting article, Karpinski and Szechynska-Hebda (2010) discuss the intellect of plants from memory to intelligence. By studying recall, the researcher investigates a host of independent variables and that are solidly anchored to a set of dependent variables. This study focused on recall at the cellular level rather than as an externally observable behavior. The discussion of plant learning at various levels, from cellular to organismal and from different scientific fields is exactly what is advocated for in this article
  • There is also interest from behavioral scientists seeking to determine whether the similarities and differences in learning found among invertebrates and vertebrates could also be found in plants (Warden et al., 1940; Applewhite, 1975; Abramson et al., 2002; Guiguet, 2013).
  • The majority of early plant studies used the Sensitive plant (M. pudica). Mimosa has much to recommend it for learning studies. They are easy to maintain, much is known about its natural history, and they have a visible leaf closure response to external stimuli. However, there are drawbacks in the use of Mimosa, for example, it takes about 15 min for a leaf to recover (Holmes and Gruenberg, 1965) and not much is known about its genome in contrast to model species such as Arabidopsis thaliana whose entire genome is known.
  • In the following section we will focus on methods to develop studies utilizing habituation, sensitization, and classical conditioning techniques. Instrumental and operant conditioning will not be covered because at this time there are no Mimosa studies in these areas; although one can envision a situation where the opening and closing of a leaf can be detected electronically. Once detected, the response would produce a consequence such as an airpuff or changes in light intensity.
    • Sean Nash
       
      The remainder of this comprehensive article is to outline the main lines of research in this area:
  • Learning in Plants: Lessons from Mimosa pudica
    • Sean Nash
       
      This well-compiled article does a really nice job of outlining the history of study regarding plant behavior. It also suggests model organisms for study. Mimosa is a favorite of mine as their response is VERY rapid and quite visible for a plant! There are all sorts of feasible project ideas that could arise from this area of research.
Sean Nash

Shining the Light on Baby Crabs | Hakai Magazine - 2 views

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    I added this one, which includes detail of an environmental study, to illustrate how creative use of everyday materials can sometimes work to design scientific methods that work!
ryleighnyp

Circadian clocks: Body parts respond to day and night independently from brain, studies... - 0 views

  • disable the entire circadian system of the mice
  • jump-start individual clocks
  • "No one realized that the liver or skin could be so directly affected by light."
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  • despite the shutdown of all other body clocks, including the central brain clock, the liver knew what time it was, responded to light changes as day shifted to night and maintained critical functions, such as preparing to digest food at mealtime and converting glucose to energy.
  • it's easy for people's circadian systems to get confused, he said. In turn, that can lead to depression, allergies, premature aging, cancer and other health problems. Further mice experiments could uncover ways to make human internal clocks "less misaligned,"
Isabella Tungjaroenkul

Anténor Firmin challenged anthropology's racist roots 150 years ago - 1 views

  • “This is hardly surprising since most of the early [Black] pioneers of anthropology have only recently been brought to light.”
    • Isabella Tungjaroenkul
       
      Sadly not surprising. There are many amazing discoveries that are overlooked and even forgotten because they were performed or written by women or non-white people.
  • It did not take long for Firmin to question his membership in a group openly hostile to people who looked like him. Faced with such a tough environment, Firmin remained silent at meetings.
katherine-medina

Marine Drugs | Free Full-Text | Microalgae Photo-Protectants and Related Bio-Carriers L... - 0 views

shared by katherine-medina on 14 Sep 23 - No Cached
Sean Nash liked it
  • This review focuses on the use of these microalgae compounds obtained by UV stimulation and takes advantage of their natural UV-resistant characteristics to potentially apply them as an alternative for UV protection products.
    • katherine-medina
       
      Can I put this on a plant in order to mitigate heat damage?
  • pproximately 90–99% of the solar UV radiation energy that reaches the Earth’s surface is UV-A
  • whereas only 1–10% is UV-B [4]. Both UV-A and UV-B are responsible for one of the biggest concerns related to UV radiation, which is skin cancer
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  • The mechanisms leading to skin damage are not fully understood and may derive from the generation of ROS and subsequent lipid peroxidation
  • To prevent photodamage, organisms have evolved to provide biochemical and physical defenses to UV by synthesizing robust bioactive compounds
  • Some algae species synthesize substances with chemical structures that can absorb UV radiation as well as inhibit actions on melanin synthesis
    • katherine-medina
       
      Which algaes
  • Microalgae can produce organic metabolites, such as sporopollenin, scytonemin, and MAAs to mention a few, and these metabolites have the purpose to protect the microalgae from UV radiation while allowing visible radiation involved in photosynthesis to pass through
  • two marine microalgae Pavlova lutheri, currently known as Diacronema lutheri, and Odontella aurita
    • katherine-medina
       
      After I get through the other ones I will get to you my pretty
  • UV-Resistant Microalgae
  • Marine organisms, including eukaryotic microalgae and cyanobacteria, during evolution, have developed physiological and biochemical traits for defense and/or tolerance to UV rays
    • katherine-medina
       
      Come back to this part
  • This research also mentioned the Antarctic microalgae Chaetoceros dichaeta, Phaeocystis antarctica, and Polarella glacialis, these were subjected to acclimation to photosynthetically active radiation (PAR) and showed resistance to UV-B rays.
  • It was found that the tolerant species contained substantial amounts of acetolysis-resistant residue
  • So far, several species, e.g., Coelastrella rubescens, Coelastrella terestris, Enallax coelastroides, Scotiella chlorelloidea, Ankistrodesmus spiralis, Chlorella minutissima, Chlorella sorokiniana, and Pseudococcomyxa sp. have been reported as rich sources of MAAs
  • They are abundant in various aquatic and terrestrial environments and are known for being eco-sustainable compounds since they are the outcome of the evolution of algae. Unlike their synthetic counterparts used unconventional sunscreens, there are no possibilities for pollution caused by them [22]. Thus, algal metabolites shape the safety and sustainability profiles of commercial sunscreens [22].
    • katherine-medina
       
      How long can the algae last on the skin or leaf of a plant
  • The results obtained point out different resistance and defense mechanisms of the four microalgae in response to UV-B irradiance and suggest that the strain of Nostoc sp. tested is the most suitable for surviving under the high UV irradiation [33]
  • Certain microalgae produce organic metabolites, such as sporopollenin, scytonemin, and MAAs as well as other UV-absorbing substances to counteract the harmful effects of UV radiation and protect themselves while allowing visible radiation involved in photosynthesis to pass through
  • The best known photoprotective response in marine organisms is the production or accumulation of UV-absorbing compounds, including MAAs as the most common compounds with such properties, but there are also others, such as scytonemin, carotenoids, alganean, and various secondary metabolites
    • katherine-medina
       
      photoprootective means protecting the skin
  • f low molecular weight, commonly found in marine environments. These compounds have absorption maxima in the UV region between 310 and 360 nm, they can dissipate radiation as heat without producing ROS. Under fixed light, MAA biosynthesis seems the most effective photoprotective mechanism
  • For these reasons, they potentially can prevent UV-induced skin damage
  • It was reported that species of microalgae that were highly tolerant to UV radiation had substantial amounts of sporopollenin. This compound functions as an antimicrobial agent, confers rigidness to the cell wall, and may further protect from UV rays by increasing the optical density, whereas species containing little or no sporopollenin were highly UV radiation susceptible
  • However, the potential of microalgae as topical photoprotectants has not been fully exploited, since there are not a lot of studies regarding this application.
  • Other reports determine that scytonemin is suspected to be synthesized from metabolites of aromatic amino acid biosynthesis
    • katherine-medina
       
      No set decision on how it is created
  • Alginate is a
  • ydration
  • However, some microalgae have a great ability to overcome or counteract different stresses such as intense solar UV radiation, this has been happening over the years and with the evolution of microalgae, some examples of defense and/or tolerance mechanisms are: DNA repair, synthesis of antioxidants, and enzymatic/non-enzymatic compounds, such as MAAs and scytonemin to counteract the harmful effects of UV radiation
  • Scytonemin is a yellow-brown lipid soluble sheath pigment that absorbs maximally in the UV-A and UV-C regions, but with some absorbance in the UV-B region. It has an in vivo absorption maximum of 370 nm.
  • tigate UV damage induced.
  • photosensitizers, their antioxidant
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    A recent article showing the potential use of microalgae as a sunscreen.
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    Yes..... let's chat this one out!
katherine-medina

Antioxidants | Free Full-Text | Drought and UV Radiation Stress Tolerance in Rice Is Im... - 0 views

  • . Plant Material, Growth Conditions, and Phenotypic EvaluationWe used the rice (Oryza sativa L.) seeds of the transgenic (OxF3H) and non-transgenic Nogdong cultivars provided by the Plant Molecular Breeding Laboratory, Kyungpook National University, Korea [41]. Rice seeds were sterilized with fungicides overnight and then washed with double distilled water three times. Next, the rice seeds were soaked in water for four days in an incubator in the dark condition at 32 °C, with the water changed after each 24 h as previously reported by [41]. After soaking and successful sprouting, rice seeds were transferred to autoclaved soil and kept in the dark again for three days. After growth, the three week rice seedlings were exposed to light and kept in a greenhouse for further experimentation.
    • katherine-medina
       
      Found ya, this study waited til rice was 3 weeks old!!!
  • 3. Results
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  • 2.8.
  • 2.9. Chlorophyll
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    "genin converts very rapidly into flavonoids in response to drought and UV-B radiation stress (see Figure 5). The close image of detection of kaempferol and quercetin is represented in Supplementary Figure S3. "
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