Skip to main content

Home/ Honors Scientific Research 2023-2024/ Group items tagged Bacteria

Rss Feed Group items tagged

katherine-medina

Peptidomimetic antibiotics disrupt the lipopolysaccharide transport bridge of drug-resi... - 0 views

  • Recently, naturally occurring peptides were proposed to interfere with the function of proteins constituting the lipopolysaccharide
  • periplasmic
    • katherine-medina
       
      The space in between the inner and outer membranes of gram-negative bacteria
  • Thanatin, a 21–amino acid defense peptide isolated from the gut of the hemipteran insect Podisus maculiventris (18), exhibits broad-spectrum antimicrobial activity
    • katherine-medina
       
      I wonder what other peptides do so as well?
  • ...7 more annotations...
  • We hypothesized that thanatin mainly acts as a competitive inhibitor of the protein-protein interactions mediating the Lpt bridge assembly
  • Thanatin, however, is not a suitable drug candidate for further development due to poor drug-like properties and rapid emergence of resistance
    • katherine-medina
       
      Why/How does thanatin have poor drug-like properties?
  • β-jellyroll
    • katherine-medina
       
      structure found in proteins
  • Here, we introduce thanatin-derived synthetic macrocyclic peptides found after a substantial medicinal chemistry effort.
    • katherine-medina
       
      Essentially they synthetically created it
  • Development of resistance against thanatin was observed after 1 day of passaging in both E. coli and K. pneumoniae and is characterized by a spontaneous FOR of 1.2 × 10−6 for E. coli at 4× MIC
    • katherine-medina
       
      That is kinda scary to think about
  • genome sequencing of a diverse panel of thanatin-resistant strains confirmed on-target modifications on LptA as the main resistance determinant in E. coli and K. pneumoniae.
  • The attractive in vitro and in vivo profile of these new antibiotics, coupled with their novel mechanism of action, showing no cross-resistance to standard of care antibiotics, may provide clinicians with additional treatment options to fight AMR, either in combination with SoC or as stand-alone antibiotics.
    • katherine-medina
       
      It is interesting to look around that these other methods that can fight off bacteria.
  •  
    An article showing a new class of antibiotics known as a peptidomimetic antibiotic.
katherine-medina

Sci-Hub | Antimicrobial activity of pomegranate fruit constituents against dr... - 0 views

    • katherine-medina
       
      The peel extracts exhibited greater antimycobacterial activity (MIC 64-1024 mg/mL) than the potable juice (MIC 256 -41024 mg/mL). Cool an early answer,
    • katherine-medina
       
      "exhibited estrogen-like activity" Why does it act like that, and that is crazy.
    • katherine-medina
       
      I think that the Hodge tests will be something important for me to look into as I go further and further down the road of polyphenolic study.
  •  
    An interesting article that basically shows that pomegranate polyphenols can kill bacteria.
katherine-medina

Restoring the activity of the antibiotic aztreonam using the polyphenol epigallocatechi... - 0 views

  • epigallocatechin gallate (EGCG) against multidrug-resistant clinical isolates of Pseudomonas aeruginosa
    • katherine-medina
       
      Epigallocatechin (EGCG) is a type of catechin or a natural phenol antioxidant. It is commonly found in tea leaves, plums, apple skin, and onions. Sidenote this bacteria is found in green tea
  • However, with resistance increasing against many classes of antibiotic, clinicians often use multiple combinations to treat critically ill patients
  • relatively low toxicity of EGCG to human keratinocytes and G. mellonella larvae.
  • ...12 more annotations...
  • . EGCG was able to restore the activity of aztreonam against MDR P. aeruginosa . The data presented support further evaluation of the aztreonam–EGCG combination and highlight its potential for use in clinical medici
  • Polyphenols
    • katherine-medina
       
      These are bioactive compounds that are found in fruits and leaves of plants. The main focus of this paper is a type of polyphenol.
  • with EGCG in checkerboard assays, susceptibility increased in P. aeruginosa (n=16, 100%), with the combination proving synergistic in all strains tested
    • katherine-medina
       
      Wow. for how much it increased the susceptibility.
  • Another option to restore the activity of aztreonam against bacterial strains with multiple resistance mechanisms would be to use polyphenols
  • he results demonstrate that synergy between aztreonam and EGCG exists [fractional inhibitory concentration indices (FICIs) 0.02-0.5], with the combination affording significantly (P=<0.05) enhanced bacterial killing, with a >3 log10 reduction in colony-forming units ml−1 at 24 h
  • To access synergy between aztreonam and EGCG, checkerboard assays were performed
  • Chemicals, media, bacterial isolates and animals
    • katherine-medina
       
      Really important to look back at these methods because even though it may not be feasible for me to do an experiment like this one, it still has valuable information for me to look at.
  • Synergy was also found between EGCG and the third-generation cephalosporin, cefotaxime
  • with scores of 64 and 56 out of a maximum of 64 for strains PA2 and PA6, respectively.
  • the increased activity may also be due to the inhibition of the non-mevalonate pathway, resulting in increased susceptibility to aztreonam.
  • Overall, the G. mellonella assays demonstrated that the aztreonam–EGCG combination was superior to monotherapy with either agent against every isolate tested, with significantly lower larval mortality rates
  • In conclusion, the results from this study demonstrate that synergy exists between aztreonam and EGCG against MDR clinical strains of P. aeruginosa in vitro and in vivo. EGCG is also able to restore the antibacterial activity of aztreonam to concentrations below the EUCAST susceptibility breakpoint for P. aeruginosa , potentially expanding and extending its useful therapeutic lifespan. Further work should be undertaken to determine if this combination has the potential to treat clinical infections caused by MDR P. aeruginosa .
    • katherine-medina
       
      My final thought for this article is as follows: 1. This brings up a very interesting topic for me to dig into (polyphenols & antibiotics)
  •  
    A gateway article for me to further my search into the scientific realm involving polyphenols that aid antibiotics.
katherine-medina

Plants | Free Full-Text | Expression of a Stilbene Synthase Gene from the Vitis labrusc... - 0 views

  • Stilbenes are found in plants of different families, but the best studied stilbene is resveratrol (3,5,4′-trihydroxystilbene) isolated from grape plants.
  • Resveratrol synthesis in transgenic plants did not always render them fully resistant to one or another pathogen.
  • The aim of our investigation was to isolate a VlvSTS stilbene synthase gene from the hybrid grape V. labrusca x V. vinifera L. and obtain transgenic tobacco plants overexpressing the gene to study their resistance to a number of bacterial and fungal pathogens, among them bacteria as E. carotovora and fungi as B. cinerea, F. oxysporum, F. sporotrichioides, F. culmorum.
  • ...16 more annotations...
  • by PCR. F
    • katherine-medina
       
      PCR is a method with which scientists are able to amplify a gene
  • Based on the results of the VlvSTS gene transcription analysis, seven transgenic tobacco lines were selected for further experiments.
  • Expression of the VlvSTS gene in tobacco plants led to a significant increase in the pollen grain size, but with a tendency to a decrease in the total number of pollen grains per anther
    • katherine-medina
       
      Too much of that gene leads to a decrease of fertility.
  • In all tests with E. carotovora bacteria, transgenic plants expressing the VlvSTS gene demonstrated a significantly higher resistance versus control plants
    • katherine-medina
       
      interesting
  • The leaf involvement was significantly smaller in transgenic plants expressing the VlvSTS gene.
  • Overexpression of the VlvSTS gene reduced the corolla pigmentation in transgenic plants.
    • katherine-medina
       
      Why did the overexpression of that gene reduce the corolla pgmentation.
  • binary vector
    • katherine-medina
       
      like a DNA transfer
  • showed a significant fertility reduction,
  • For the first time it was shown that plants expressing the VlvSTS gene had enhanced resistance to the bacterial pathogen E. carotovora subsp. carotovora B15.
    • katherine-medina
       
      Interesting that it took this long for it to be shown that this specific stilbene can fight against certain pathogens.
  • Interestingly, resistance correlated with the expression level of the stilbene synthase gene. In plants with a higher gene expression (L10 and L23), the area of Erwinia-caused leaf damage was in a range from 0 to 40% respect to the control, while the leaves of line L24 were affected up to 60–100%.
  • hile in transgenic lines, the lysis areas were significantly smaller, probably due to the synthesis of the phytoalexin resveratrol.
  • Some studies showed that Arabidopsis plants transformed with wild grape stilbene synthase genes responded to a pathogen attack by activating genes responsible for the synthesis of signaling molecules such as salicylic and jasmonic acids (SA and JA, respectively) [
  • Our data show a decrease in the total flavonoid content in the flower petals but not in the leaves of plants upon expression of the VlvSTS gene.
    • katherine-medina
       
      That seems rather odd.
  • We were the first to show that transgenic tobacco plants carrying the VlvSTS gene had a significantly larger pollen grain size and a smaller number of pollen grains per anther. At the same time, the number of fertile pollen grains decreased, especially in the plant line with the highest expression of the VlvSTS gene.
  • For example, in apple plants with the grape stilbene synthase gene Vst1 under its own promoter, the expression of the gene had no effect on pollen development
  • The study showed that the expression of a VlvSTS stilbene syntase gene in tobacco transgenic plants increases their resistance to bacterial pathogen E. carotovora. There was a significant reduction of disease symptoms after infection of leaves by grey mould fungus B. cinerea, but not to Fusarium fungi. We were the first to show that transgenic tobacco plants carrying the VlvSTS gene had a significantly larger pollen grain size and a smaller number of pollen grains per anther. The number of fertile pollen grains decreased, especially in the plant line with the highest expression of the VlvSTS gene. These changes resulted in a decreased weight of seed bolls in the transgenic tobacco lines.
    • katherine-medina
       
      Overall, this article is one that I may come back to depending on what path I go down when searching to develop a research topic further.
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
  • ...25 more annotations...
  • 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.
  • 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.
  • γ rays
    • katherine-medina
       
      I had no idea these were a thing.
  • 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.
  • 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.
  • 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.
  • 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.
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
  • ...17 more annotations...
  • 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].
  • Baicalin [8], diterpenes [9], tellimagrandin I [10], corilagin [11], tripeptide [12], epigallocatechin gallate (EGCg) [13] and epicatechin gallat
  • Figure 1
    • katherine-medina
       
      I could do something similar to this in a Petree dish like the photo above.
  • 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,
  • 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
  • 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.
  • 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.
  • 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.
  • 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
  • . 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.
  • Sh
  •  
    An article discussing the affects of combining polyphenols with antibiotics in order to fight against MRSA.
katherine-medina

(1) Polyphenolic Secondary Metabolites Synergize the Activity of Commercial A... - 1 views

  •  
    An article showing how different polyphenols can enhance antibiotics.
katherine-medina

A virus of hyperthermophilic archaea with a unique architecture among DNA viruses | PNAS - 0 views

  • ssDNA, ssRNA, and ds
  • One of these isolates was subjected to an additional round of colony purification, and the isolated strain, designated “2GA,” was selected as a standard virus host for all following experiments, unless stated otherwise.
  • Cells of the 2GA isolate are rod-shaped, with an average length of about 4 μm and a width of about 0.7 μm.
  • ...1 more annotation...
  • A combination
katherine-medina

Anti-Oxidative and Anti-Inflammatory Effects of Ginger in Health and Physical Activity:... - 1 views

  • the rhizome
  • Ginger has staring potential for treating a number of ailments including degenerative disorders (arthritis and rheumatism), digestive health (indigestion, constipation and ulcer), cardiovascular disorders (atherosclerosis and hypertension), vomiting, diabetes mellitus, and cancer.
    • katherine-medina
       
      It has the potential for it, so there may not be many studies on these different things that ginger can supposedly do. So it makes me Infinitely more curious to look and see if there are other studies that actually have information about these said claims.
  • Furthermore, it has antimicrobial potential as well which can help in treating infectious diseases.[2
  • ...17 more annotations...
  • The bioactive molecules of ginger like gingerols have shown antioxidant activity in various modules
  • Inflammatory disorders such as gastritis, esophagitis, and hepatitis, which are caused not only by infectious agents such as viruses, bacteria, and parasites but also by physical and chemical agents like heat, acid, cigarette smoke, and foreign bodies, are recognized as risk factors for human cancer
  • This study aimed to review the current evidence on ginger effects as an anti-inflammatory and anti-oxidative.
  • es.[2
  • 6-Shogaol has exhibited the most potent antioxidant and anti-inflammatory properties in ginger, which can be attributed to the presence of alpha, beta-unsaturated ketone moiety
  • Furthermore, feeding ginger to rats at 1% w/w during administration of malathion
    • katherine-medina
       
      Wow, so they fed the rats pesticides than ginger
  • so it can possibly value in treatment of Parkinson's disease.[17]
    • katherine-medina
       
      Really cool
  • This effect was improved by a treatment with 1% dietary ginger 1 month in rats which suggest that ginger may have protective role against the ethanol induced hepatotoxicity.
  • could be useful in preventing acute liver injury
  • Habib et al. showed that ginger extract can reduce the elevated expression of NFκB and TNF-α in rats with liver cancer
  • howed that gingerols can inhibit LPS-induced COX-2 expression while shogaol containing extracts has no effect on COX-2 expression
  • Ginger and its bioactive molecules are effective in controlling the extent of colorectal, gastric, ovarian, liver, skin, breast, and prostate cancers
    • katherine-medina
       
      Wow it can do a lot.
  • They observed that [6]-gingerol inhibits TRAIL-induced NF-κB activation by impairing the nuclear translocation of NF-κB, suppresses cIAP1 expression, and increases TRAIL-induced caspase-3/7 activation
  • Inhibition of angiogenesis in the mouse skin is the mechanism of ginger for treating of skin cancer.
  • However, ginger significantly lowered blood glucose, serum total cholesterol, LDL, VLDL, and triglycerides, and raised HDL in hyperglycemic rats, in models that are diabetic, deficient in the apolipoprotein E gene or those that have been fed a high lipid diet.
  • ethanolic extract of ginger reduced body weights and levels of glucose, insulin, total cholesterol, LDL cholesterol, triglycerides, free fatty acids, and phospholipids in high-fat diets.
  • CONCLUSIONS
    • katherine-medina
       
      Overall a good synopsis on what ginger can do.
lincolnt

Structure and function of bacteriophage T4 - PMC - 0 views

  • The 194 MDa mature head encapsidates 172 kbp dsDNA, representing 102% of the unique genome [24,25]. The head is first assembled as an empty capsid that is subsequently packaged with DNA by an ATP-dependent packaging machine. This machine binds to the same special pentameric vertex that is later occupied by the phage tail. The head is prolate, meaning that it has two icosahedral ends and a cylindrical mid-section.
1 - 13 of 13
Showing 20 items per page