scholarly journals Synthetic Biomimetic Polymethacrylates: Promising Platform for the Design of Anti-Cyanobacterial and Anti-Algal Agents

Polymers ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1025
Author(s):  
Přemysl Mikula ◽  
Marie Mlnaříková ◽  
Enrico T. Nadres ◽  
Haruko Takahashi ◽  
Pavel Babica ◽  
...  

Extensive, uncontrolled growth of algae and cyanobacteria is an environmental, public health, economic, and technical issue in managing natural and engineered water systems. Synthetic biomimetic polymers have been almost exclusively considered antimicrobial alternatives to conventional antibiotics to treat human bacterial infections. Very little is known about their applicability in an aquatic environment. Here, we introduce synthetic biomimetic polymethacrylates (SBPs) as a cost-effective and chemically facile, flexible platform for designing a new type of agent suitable for controlling and mitigating photosynthetic microorganisms. Since SBPs are cationic and membranolytic in heterotrophic bacteria, we hypothesized they could also interact with negatively charged cyanobacterial or algal cell walls and membranes. We demonstrated that SBPs inhibited the growth of aquatic photosynthetic organisms of concern, i.e., cyanobacteria (Microcystis aeruginosa and Synechococcus elongatus) and green algae (Chlamydomonas reinhardtii and Desmodesmus quadricauda), with 50% effective growth-inhibiting concentrations ranging between 95 nM and 6.5 μM. Additionally, SBPs exhibited algicidal effects on C. reinhardtii and cyanocidal effects on picocyanobacterium S. elongatus and microcystin-producing cyanobacterium M. aeruginosa. SBP copolymers, particularly those with moderate hydrophobic content, induced more potent cyanostatic and cyanocidal effects than homopolymers. Thus, biomimetic polymers are a promising platform for the design of anti-cyanobacterial and anti-algal agents for water treatment.

Antibiotics ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 650
Author(s):  
Kylen E. Ridyard ◽  
Joerg Overhage

The rise in antimicrobial resistant bacteria threatens the current methods utilized to treat bacterial infections. The development of novel therapeutic agents is crucial in avoiding a post-antibiotic era and the associated deaths from antibiotic resistant pathogens. The human antimicrobial peptide LL-37 has been considered as a potential alternative to conventional antibiotics as it displays broad spectrum antibacterial and anti-biofilm activities as well as immunomodulatory functions. While LL-37 has shown promising results, it has yet to receive regulatory approval as a peptide antibiotic. Despite the strong antimicrobial properties, LL-37 has several limitations including high cost, lower activity in physiological environments, susceptibility to proteolytic degradation, and high toxicity to human cells. This review will discuss the challenges associated with making LL-37 into a viable antibiotic treatment option, with a focus on antimicrobial resistance and cross-resistance as well as adaptive responses to sub-inhibitory concentrations of the peptide. The possible methods to overcome these challenges, including immobilization techniques, LL-37 delivery systems, the development of LL-37 derivatives, and synergistic combinations will also be considered. Herein, we describe how combination therapy and structural modifications to the sequence, helicity, hydrophobicity, charge, and configuration of LL-37 could optimize the antimicrobial and anti-biofilm activities of LL-37 for future clinical use.


2016 ◽  
Vol 22 (2) ◽  
pp. 258-263 ◽  
Author(s):  
Gábor Steinbach ◽  
Radek Kaňa

AbstractPhotosynthesis research employs several biophysical methods, including the detection of fluorescence. Even though fluorescence is a key method to detect photosynthetic efficiency, it has not been applied/adapted to single-cell confocal microscopy measurements to examine photosynthetic microorganisms. Experiments with photosynthetic cells may require automation to perform a large number of measurements with different parameters, especially concerning light conditions. However, commercial microscopes support custom protocols (throughTime Controlleroffered by Olympus orExperiment Designeroffered by Zeiss) that are often unable to provide special set-ups and connection to external devices (e.g., for irradiation). Our new system combining an Arduino microcontroller with theCell⊕Findersoftware was developed for controlling Olympus FV1000 and FV1200 confocal microscopes and the attached hardware modules. Our software/hardware solution offers (1) a text file-based macro language to control the imaging functions of the microscope; (2) programmable control of several external hardware devices (light sources, thermal controllers, actuators) during imaging via the Arduino microcontroller; (3) theCell⊕Findersoftware with ergonomic user environment, a fast selection method for the biologically important cells and precise positioning feature that reduces unwanted bleaching of the cells by the scanning laser.Cell⊕Findercan be downloaded fromhttp://www.alga.cz/cellfinder. The system was applied to study changes in fluorescence intensity inSynechocystissp. PCC6803 cells under long-term illumination. Thus, we were able to describe the kinetics of phycobilisome decoupling. Microscopy data showed that phycobilisome decoupling appears slowly after long-term (>1 h) exposure to high light.


Chemosensors ◽  
2021 ◽  
Vol 9 (3) ◽  
pp. 49
Author(s):  
Pushap Raj ◽  
Man Hwan Oh ◽  
Kyudong Han ◽  
Tae Yoon Lee

Bacterial infections have become a significant challenge in terms of public health, the food industry, and the environment. Therefore, it is necessary to address these challenges by developing a rapid, cost-effective, and easy-to-use biosensor for early diagnosis of bacterial pathogens. Herein, we developed a simple, label-free, and highly sensitive immunosensor based on electrochemical detection using the Au@MoS₂–PANI nanocomposite. The conductivity of the glassy carbon electrode is greatly enhanced using the Au@MoS₂–PANI nanocomposite and a self-assembled monolayer of mercaptopropionic acid on the gold nanoparticle surface was employed for the covalent immobilization of antibodies to minimize the nonspecific adsorption of bacterial pathogens on the electrode surface. The biosensor established a high selectivity and sensitivity with a low limit of detection of 10 CFU/mL, and detected Escherichia coli within 30 min. Moreover, the developed biosensor demonstrated a good linear detection range, practical utility in urine samples, and electrode regenerative studies.


Toxins ◽  
2018 ◽  
Vol 10 (12) ◽  
pp. 522 ◽  
Author(s):  
Paula Segura-Ramírez ◽  
Pedro Silva Júnior

The remarkable ability of microorganisms to develop resistance to conventional antibiotics is one of the biggest challenges that the pharmaceutical industry currently faces. Recent studies suggest that antimicrobial peptides discovered in spider venoms may be useful resources for the design of structurally new anti-infective agents effective against drug-resistant microorganisms. In this work, we found an anionic antibacterial peptide named U1-SCRTX-Lg1a in the venom of the spider Loxosceles gaucho. The peptide was purified using high-performance liquid chromatography (HPLC), its antimicrobial activity was tested through liquid growth inhibition assays, and its chemical properties were characterized using mass spectrometry. U1-SCRTX-Lg1a was found to show a monoisotopic mass of 1695.75 Da, activity against Gram-negative bacteria, a lack of hemolytic effects against human red blood cells, and a lack of cytotoxicity against human cervical carcinoma cells (HeLa). Besides this, the sequence of the peptide exhibited great similarity to specific regions of phospholipases D from different species of Loxosceles spiders, leading to the hypothesis that U1-SCRTX-Lg1a may have originated from a limited proteolytic cleavage. Our data suggest that U1-SCRTX-Lg1a is a promising candidate for the development of new antibiotics that could help fight bacterial infections and represents an exciting discovery for Loxosceles spiders.


2020 ◽  
Author(s):  
Yusen Shen ◽  
Jiansheng Wang ◽  
Huifang Yu ◽  
Xiaoguang Sheng ◽  
Zhenqing Zhao ◽  
...  

Abstract Background: Broccoli (Brassica oleracea var. italica) is a vegetable widely cultivated in China. Many new-type broccoli cultivars were bred and developed by Chinese breeders during the recent three decades. However, the broccoli cultivar nomenclature and detailed information of genetic relationships among broccoli germplasms are unclear. Results: The present study identified millions of SNPs by next-generation sequencing of 23 representative broccoli lines. Through several steps of selection, 100 SNPs were successfully converted into KASP markers, and used to evaluate the genetic diversity, genetic relationship, and population structure of 392 broccoli accessions, which represent the mainly broccoli breeding materials in China. The initial, introduced and improved accessions were well clustered, though some accessions were overlapped between groups, probably reflecting the fact that breeding activities led to genetic similarities. To make the KASP genotyping more efficient and cost-effective, 25 of the 100 KASPs were selected for fingerprinting of all accessions, and the 2D barcode contained fingerprinting information were generated for elite varieties. Conclusion: The KASP markers developed in this study provided an efficient way for germplasm characterization, DNA fingerprinting, seed purity identification, and marker-assisted selection of broccoli in China.


PLoS ONE ◽  
2021 ◽  
Vol 16 (4) ◽  
pp. e0249930
Author(s):  
Aziz Belkadi ◽  
Gaurav Thareja ◽  
Darshana Dadhania ◽  
John R. Lee ◽  
Thangamani Muthukumar ◽  
...  

Kidney transplantation is the treatment of choice for patients with end-stage kidney failure, but transplanted allograft could be affected by viral and bacterial infections and by immune rejection. The standard test for the diagnosis of acute pathologies in kidney transplants is kidney biopsy. However, noninvasive tests would be desirable. Various methods using different techniques have been developed by the transplantation community. But these methods require improvements. We present here a cost-effective method for kidney rejection diagnosis that estimates donor/recipient-specific DNA fraction in recipient urine by sequencing urinary cell DNA. We hypothesized that in the no-pathology stage, the largest tissue types present in recipient urine are donor kidney cells, and in case of rejection, a larger number of recipient immune cells would be observed. Extensive in-silico simulation was used to tune the sequencing parameters: number of variants and depth of coverage. Sequencing of DNA mixture from 2 healthy individuals showed the method is highly predictive (maximum error < 0.04). We then demonstrated the insignificant impact of familial relationship and ethnicity using an in-house and public database. Lastly, we performed deep DNA sequencing of urinary cell pellets from 32 biopsy-matched samples representing two pathology groups: acute rejection (AR, 11 samples) and acute tubular injury (ATI, 12 samples) and 9 samples with no pathology. We found a significant association between the donor/recipient-specific DNA fraction in the two pathology groups compared to no pathology (P = 0.0064 for AR and P = 0.026 for ATI). We conclude that deep DNA sequencing of urinary cells from kidney allograft recipients offers a noninvasive means of diagnosing acute pathologies in the human kidney allograft.


2020 ◽  
Vol 2 (7A) ◽  
Author(s):  
Faith Ukachukwu ◽  
Lori Snyder ◽  
Raid Alany

Pseudomonas aeruginosa and Staphylococcus aureus are bacteria pathogens that cause a myriad of infections affecting various sites in the body including the eyes, ears, lungs, skin, heart, bones, and blood amongst others. These bacteria can be disseminated via the blood to other parts of the body away from the primary site of infection and consequences vary from mild to severe with death occurring in certain instances. Both bacterial infections can occur individually, as well as in co-infection resulting in even worse outcomes. P. aeruginosa and S. aureus exhibit multidrug resistance against current antibiotic treatment regimens, which accentuates the challenge in managing the infections caused by these bacteria. To prevent the looming era of untreatable bacterial infections, alternative treatment regimens that are cost effective and accessible are needed. To explore novel treatment options, twenty-five organic compounds comprising fatty acids and their derivatives were screened for antibacterial activity in broth microdilution assay to determine the minimum inhibitory concentration and minimum bactericidal concentration against both P. aeruginosa and S. aureus. Five candidates (N–nonanoic acid, butyric acid, heptanoic acid, palmitoleic acid, and isopropyl myristate) were effective against P. aeruginosa. Seven candidates (N–nonanoic acid, palmitoleic acid, tridecanoic acid, sebaic acid, undecanoic acid, monolaurin, and monocaprin) were effective against S. aureus. Candidates such as N–nonanoic acid and palmitoleic acid were effective against both P. aeruginosa and S. aureus, demonstrating that the same fatty acids show potential to be used against both Gram negative and Gram positive bacterial infections.


Author(s):  
Dafne Bongiorno ◽  
Nicolò Musso ◽  
Paolo Giuseppe Bonacci ◽  
Dalida A. Bivona ◽  
Mariacristina Massimino ◽  
...  

The widespread use of antibiotics has led to a gradual increase in drug-resistant bacterial infections, which severely weakens the clinical efficacy of antibacterial therapies. In recent decades, stilbenes aroused great interest because of their high bioavailability, as well as for their manifold biological activity. Our research efforts are focused on synthetic heteroaromatic stilbene deriva-tives as they represent a potentially new type of antibiotic with a wide antibacterial spectrum. Herein, a preliminary molecular modeling study and a versatile synthetic scheme allowed us to define eight heteroaromatic stilbene derivatives with potential antimicrobial activity. In order to evaluate our compound&rsquo;s activity spectrum and antibacterial ability, Minimum Inhibitory Con-centration (MIC) and Minimum Bactericidal Concentration (MBC) tests have been performed on Gram-positive and Gram-negative ATCC strains. Compounds PB4, PB5, PB7 and PB8 showed the best values in terms of MIC and were also evaluated for MBC, which however was found to be greater than MIC, confirming a bacteriostatic activity. For all compounds, we evaluated toxici-ty on colon-rectal adenocarcinoma cells tumor cells (CaCo2), once established that the whole se-lected set was more active than 5-Fluorouracil in reducing CaCo-2 cells viability. To the best of our knowledge, the biological assays have shown for these derivatives an excellent bacteriostatic activity, compared to similar molecular structures previously reported, thus paving the way for a new class of antibiotic compounds.


Author(s):  
Erin Cieslak ◽  
James P. Mack ◽  
Albert Rojtman

<p><strong>Objective: </strong>Essential oils are of significant interest in today’s world of healthcare because these compounds have a variety of medicinal properties. In this study, we evaluated the <em>in vitro</em> antibiotic role of essential oils as a possible alternative treatment in combatting Methicillin-resistant <em>Staphylococcus aureus</em> (MRSA).</p><p><strong>Methods: </strong>In conjunction with carrier oils, three essential oils (cassia, cinnamon bark, and thyme), as well as methylglyoxal were tested on MRSA using the Kirby-Bauer disc diffusion method.</p><p><strong>Results: </strong>The minimum inhibitory concentration of each tested essential oil and methylglyoxal in carrier oil was determined to be 25% essential oil and 75% carrier oil mixture. This concentration worked much more effectively than the standard antibiotic, vancomycin, which is currently used to treat MRSA infections.</p><p><strong>Conclusion: </strong>Antibacterial emollients made from naturally occurring products like essential oils can be cost-effective alternatives to antibiotics. The results of this research show that these emollients are more effective against MRSA than standard antibiotics in cell culture.</p>


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