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katherine-medina

Frontiers | Dietary Polyphenols and Their Role in Oxidative Stress-Induced Human Diseas... - 1 views

  • phenolic acids, flavonoids, catechins, tannins, lignans, stilbenes and anthocyanidins
  • They possess antioxidant, chemopreventive and a wide range of pharmacological properties (
  • Over 8,000 polyphenols have been reported from plants, out of several hundreds of polyphenols exist in human diets
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  • Organic compounds bearing an aromatic ring with at least one hydroxyl group are termed as “phenolics”. In case, a compound possesses one or more aromatic rings having more than one hydroxyl group are called polyphenols (or polyphenolic compounds).
  • As per the C1-C6 or C3-C6 backbone, they are usually referred to as derivatives of benzoic acid or cinnamic acid
  • However, the role of the dietary polyphenols of their antioxidant abilities is still unclear.
    • katherine-medina
       
      How exactly is the role of antioxidants unclear?
  • Increased intake of foods containing polyphenols (for example, quercetin, epigallocatechin-3-gallate, resveratrol, cyanidin etc.) has been claimed to lower the incidence of a majority of chronic oxidative cellular damage, DNA damage, tissue inflammations, various cancers, viral/bacterial infections, and neurodegenerative diseases
    • katherine-medina
       
      So an increase of foods with natural extracts, so just plain vegetables that are not processed.
  • γ rays
    • katherine-medina
       
      I had no idea these were a thing.
  • This review specifically focuses a current understanding on the dietary sources of polyphenols and their protective effects including mechanisms of action against various major human diseases.
  • ROS when increased or excessively produced can cause oxidative changes/damages to all cellular macromolecules
  • Several antioxidant enzymes such as superoxide dismutase (SOD), catalase (CAT), and reduced glutathione (GSH) aid in the removal of free radicals
  • Peroxynitrite can also destroy lipoproteins and causes lipid peroxidation of cell membranes
  • ROS can also affect protein synthesis and protein functions. Protein oxidation can result in amino acid modifications
  • Flavonoids are further classified into different subgroups based on their structures such as flavan-3-ols (examples: catechin, epicatechin, epigallocatechin), isoflavones (examples: genistein, genistin, daidzenin, daidzin, biochanin A, formononetin), flavones (examples: luteolin, apigenin, chrysin), flavonones (examples: hesperetin, naringenin), flavonols (examples: quercetin, kaempferol, galangin, fisetin, myricetin), flavononol (example: taxifolin), flavylium salts (examples: cyanidin, cyanin, pelargonidin), and flavanones (examples: hesperetin, naringenin, eriodictyol, isosakuranetin)
    • katherine-medina
       
      WOW so flavonoids have a large variety and classes.
  • urther, OS exerts deleterious effects on DNA leading to the formation of DNA lesions, which can result in genomic instability and consequently lead to cell death.
  • Polyphenols are found naturally in fruits and vegetables such as cereals, pulses, dried legumes, spinach, tomatoes, beans, nuts, peppermint, cinnamon, pears, cherries, oranges, apples, red wine, tea, cocoa, coffee and so on (Arts and Hollman, 2005; Scalbert et al., 2005). Polyphenols are classified into different groups depending on the number of aromatic (phenolic) rings they contain and the structural elements that connect these rings. They are broadly grouped into phenolic acids, flavonoids, stilbenes and lignans
    • katherine-medina
       
      SO each polyphenol has a different number of phenolic rings. What is the difference between the different polyphenols such as phenolic acid, flavonoids, stilbenes and lignans. I think that I should look at which of these groups are more effective when working with antibiotics as a way to aid them in the fight against resistant bacterias.
  • In plant derived polyphenolic compounds, flavonoids comprise the largest group with an approximately 10,000 natural analogues
  • Dietary supplements containing elevated amounts of flavonoids from strawberries, lettuce, or blueberries aid in the reversal of age-related discrepancies in the brain and behavioral control in aged rats
  • Tea catechins
    • katherine-medina
       
      I ha e looked into these a bit, but I did not know that they can help with neurodegenerative diseases.
  • reduced glutathione (GSH), and on membrane sulphydryl (-SH) group in humans has been reported by Maurya and Rizvi (2009).
  • OS can be the primary or secondary reason for various CVDs. Preclinical evidence support that OS is linked to a variety of CVDs, including atherosclerosis, ischemia, stroke, cardiomyopathy, cardiac hypertrophy, and hypertension, as well as congestive heart failure
  • Dietary flavonoids may reduce endothelial disorders linked with various risk factors for atherosclerosis before plaque creation
  • The polyphenols of Hibiscus sabdariffa weaken diabetic nephropathy in terms of serum lipid profile and kidney oxidative markers
  • . Studies suggest that a diet that includes regular consumption of fruits and vegetables (rich in polyphenols such as catechins, resveratrol, ellagic acid, naringenin, quercetin etc.) significantly lowers the risk of developing many cancers.
  • Black tea polyphenols like EGCG, theaflavins and thearubigins have potent anticancer properties
  • Anti-carcinogenic effects of resveratrol are due to the antioxidant function, which inhibits hydroperoxidase, Akt (PI3K-Akt) signaling pathway, matrix metalloprotease-9, NF-kB, protein kinase C, cyclooxygenase, focal adhesion kinase and Bcl-2 (B cell lymphoma 2) biomarkers/enzymes (Athar et al., 2007)
  • Increased OS may lead to the vulnerability of the infection and also triggers the malfunctioning of cellular metabolism
  • Resveratrol shows its anti-rheumatoid arthritis properties with reduced RA patients’ swelling, tenderness, and disease activity by lowering the biochemical indicators of inflammation like MMP-3, IL-6, ESR, C-reactive protein, and undercarboxylated osteocalcin
  •  
    A good overview about polyphenols.
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.
katherine-medina

IJMS | Free Full-Text | The Combination of Catechin and Epicatechin Gallate f... - 1 views

  • efflux
  • efflux pumps
    • katherine-medina
       
      Wow, so MRSA can literally pump out antibiotics.
  • The advantage of the agents is that there is little or no direct selective pressure, and thus resistant strains are less likely to emerge
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  • Figure 1
    • katherine-medina
       
      I could do something similar to this in a Petree dish like the photo above.
  • Baicalin [8], diterpenes [9], tellimagrandin I [10], corilagin [11], tripeptide [12], epigallocatechin gallate (EGCg) [13] and epicatechin gallat
  • The extracts and compounds from hawthorn have been reported to show a variety of pharmacological activities, such as a protective effect on patients with heart failure [17], as well as an increased force of myocardial contraction [18], improved coronary circulation [19], antioxidant effects [20] and antimicrobial activities [21].
  • For example, galloy catechins, such as ECg and Cg, reduced the high MIC level of β-lactams to the antibiotic breakpoint or even lower than the breakpoint [14,15,26,27], but non-galloylated catechins, such as C and EC, had no such effect
    • katherine-medina
       
      use galloy catechins
  • WHO-2 but ECg (32 mg/L) increased the drug accumulation
    • katherine-medina
       
      So, at this specific concentration ECg helped with increasing the amount of antibiotic, but not necessarily assisting the ability of the antibiotic to do damage.
  • C or ECg (32 mg/L) in combination with oxacillin produced FICIs of more than 0.5 or 0.5, demonstrating no or very weak ILSMR effect.
  • via inhibiting mRNA expression of efflux pump genes,
  • Some natural products can enhance the efficacy of β-lactam antibiotics, and therefore they are termed intensifiers of β-lactam susceptibility in MRSA
    • katherine-medina
       
      I would like to look into using antibiotics that are currently available to the public, and trying to enhance their ability to fight bacteria through the use of certain polyphenols or some other type of natural product.
  • In traditional Chinese medicine, hawthorn is used as a peptic agent for stimulating digestion and promoting the function of the stomach, improving blood circulation and removing blood stasis
  • We also found that when C combined with ECg, the ILSMR effect was markedly increased and the ILSMR effect of the combination (C and ECg) was enhanced with the increase in the concentration of C, with a higher concentration of C resulting in a lower FICI.
  • Overall, the different abilities of C and EGC to potentiate the ILSMR effect of ECg was presumed to be due to the difference in steric hindrance provided by the hydroxy groups in the B ring of these compounds.
  • Our results showed that C in combination with ECg could significantly reduce the MIC of these six antibiotics against almost all of the clinical MRSA strains
  • These results are significant since they demonstrate the possibility that these antibiotics can be used in the clinic when combined with C and ECg.
    • katherine-medina
       
      I wonder if they have started implementing this in hospitals.
  • . Therefore, a criterion suitable for more than two compounds should be investigated in the future.
    • katherine-medina
       
      I think that this will be a useful article to go back to when looking towards developing further ideas for experiments.
  • he above results suggested the ILSMR effect of C and ECg was probably related to the inhibition of three pumps’ mRNA expressions. Which pump(s) played a more important role should be further investigated in the future experiments.
    • katherine-medina
       
      Interesting
  • Herein, our results showed that reserpine down-regulated mRNA expressions of norA and norC, but not abcA, and C, in combination with ECg, down-regulated mRNA expressions of norA, norC and abcA among eight efflux pumps, while ECg or C alone could not.
  • Sh
  •  
    An article discussing the affects of combining polyphenols with antibiotics in order to fight against MRSA.
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