Bacterial Cell Proliferation Research Articles

Synthetic strategy for the production of electrically polarized polyvinylidene fluoride-trifluoroethylene-co-polymer osseo-functionalized with hydroxyapatite scaffold.

The physiological mechanism of bone tissue regeneration is intricately organized and involves several cell types, intracellular, and extracellular molecular signaling networks. To overcome the drawbacks of autografts and allografts, a number of synthetically produced scaffolds have been manufactured by integrating ceramics, polymers, and their hybrid-composites. Considering the fact that natural bone is composed primarily of collagen and hydroxyapatite, ceramic-polymer composite materials seem to be the most viable alternative to bone implants. Here, in this experimental study, copolymer PVDF-TrFE has been amalgamated with HA ceramics to produce composite scaffolds as bone implants. In order to fabricate PVDF-TrFE-HA (polyvinylidene fluoride-trifluoroethylene-hydroxyapatite) composite scaffolds, solvent casting-particulate leaching technique was devised. Two scaffold specimens were produced, with different PVDF-TrFE and HA molar ratios (70:30 and 50:50), and then electrically polarized to observe the subsequent polarization impact on the tissue growth and the suppression of bacterial cell proliferation. Both the specimens underwent characterization to analyze their biocompatibility and bactericidal activities. The bacterial culture of Pseudomonas aeruginosa (P. aeruginosa) and Staphylococcus aureus (S. aureus) bacteria on the composites was studied to understand the antibacterial characteristics. Moreover, MG63 cells cultured on these as-formed composites provided information about osteogenesis. Improved osteogenesis and antibacterial efficacy were observed on both the composites. However, the composite with 70 wt% PVDF-TrFE and 30 wt% HA showed a higher bactericidal effect as well as osteogenesis. It was found that PVDF-TrFE-HA-based biomaterials have the potential for bone tissue engineering applications.

Quorum-sensing gene regulates hormetic effects induced by sulfonamides in Comamonadaceae.

Antibiotics can induce dose-dependent hormetic effects on bacterial cell proliferation, i.e., low-dose stimulation and high-dose inhibition. However, the underlying molecular basis has yet to be clarified. Here, we showed that sulfonamides play dual roles as a weapon and signal against Comamonas testosteroni that can modulate cell physiology and phenotype. Subsequently, through investigating the hormesis mechanism, we proposed a comprehensive regulatory pathway for the hormetic effects of Comamonas testosteroni low-level sulfonamides and determined the generality of the observed regulatory model in the Comamonadaceae family. Considering the prevalence of Comamonadaceae in human guts and environmental ecosystems, we provide critical insights into the health and ecological effects of antibiotics.

Initiation of Apoptotic Pathway by the Cell-Free Supernatant Synthesized from Weissella cibaria Through In-Silico and In-Vitro Methods.

Globally, colorectal cancer is the most prevalent type of cancer. Even though multiple treatments such as surgery, radiation, chemotherapy, and immunotherapy are available, the adverse effects caused in patients seem remarkable. Therefore, the current work was deliberated to prepare the metabolites (cell-free supernatant-CFS) from Weissella cibaria RK-3-1 to conduct in-silico and in-vitro-based anticancer assays. First, the active biomolecules present in the CFS were screened using a GC-MS analyzer. In addition, in-silico-based pharmacokinetic and docking studies were performed to confirm the anticancer potential of metabolites. In-silico results suggested that the bioactive compounds such as filicinic acid, dibutyl phthalate, and 4H-pyran-4-one,2,3-dihydro-3,5-dihydroxy-6-methyl present in CFS possessed significant molecular docking interactions with anticancer hub proteins. Furthermore, in-vitro results displayed the inhibition of cell proliferation in HT-29 cells at an IC50 value of 22.5 ± 1.3µg/ml with the least significant effect on HEK-293 cell lines. Moreover, bacterial metabolites-controlled cell proliferation during the cell cycle's synthesis phase (S). Furthermore, the gene expression results confirm the increased expression of Bad, Bax, Bcl2, caspase-3, and cytochrome-C genes involved in the intrinsic apoptotic pathway. Hence, our findings from the in-silico and the in-vitro study confirm the anticancer potential of cell free-supernatant synthesized by W. cibaria.

Microplastics Enhance the Prevalence of Antibiotic Resistance Genes in Anaerobic Sludge Digestion by Enriching Antibiotic-Resistant Bacteria in Surface Biofilm and Facilitating the Vertical and Horizontal Gene Transfer.

Antibiotic resistance genes (ARGs) and microplastics (MPs) are recognized as emerging contaminants and threats to global human health. Despite both of them being significantly detected in their "hotspots", i.e., waste activated sludge (WAS), rare studies on how MPs affect ARGs and antibiotic-resistant bacteria (ARB) in anaerobic sludge digestion are available. Herein, the fate of ARGs and ARB after exposure to MPs of three dosages (10, 30, and 80 particles/g-TS), three polymer types (LDPE, PET, and PS), and three branching extents (LDPE, LLDPE, and HDPE) in anaerobic sludge digestion was investigated. Metagenomic results indicated that all variants of MPs resulted in an increase of the relative abundance of ARGs in the digester compared to the control. The abundance of ARGs demonstrated a dosage-dependent relationship within the range from 10 to 80 particles/g-TS, resulting in an increase from 4.5 to 27.9% compared to the control. Branching structure and polymer type influence ARG level in the sludge digester as well. Mechanism studies revealed that LDPE selectively enriched potential ARB and ARGs in the surface biofilm, possibly creating a favorable environment for ARB proliferation and ARG exchange. Furthermore, vertical transfer of ARGs was facilitated by LDPE through increasing bacterial cell proliferation accompanied by the enhancement of relevant functional genes. The elevated abundance of mobile genetic elements (MGEs) and ARGs-carrying plasmids also demonstrated that MGE-mediated horizontal transfer was promoted by LDPE at 80 particles/g-TS. This effect was compounded by increased oxidative stress, cell membrane permeability, and cell cohesion, collectively facilitating horizontal ARG transfer. Consequently, both vertical and horizontal transfer of ARGs could be concurrently promoted by LDPE an in anaerobic sludge digester.

Antibacterial Efficacy and Surface Characteristics of Boron Nitride Coated Dental Implant: An In-Vitro Study.

This in vitro study evaluated bacterial cell proliferation and biofilm adhesion on titanium discs with and without antibacterial surface treatment to reduce the chances of peri-implant infections. Hexagonal boron nitride with 99.5% purity was converted to hexagonal boron nitride nanosheets via the liquid phase exfoliation process. The spin coating method was used for uniform coating of h-BNNSs over titanium alloy (Ti6Al4V) discs. Two groups of titanium discs were formed: Group I (n = 10) BN-coated titanium discs and Group II (n = 10) uncoated titanium discs. Two bacterial strains, Streptococcus mutans (initial colonizers) and Fusobacterium nucleatum (secondary colonizers), were used. A zone of inhibition test, microbial colony forming units assay, and crystal violet staining assay were used to evaluate bacterial cell viability. Surface characteristics and antimicrobial efficacy were examined by scanning electron microscopy with energy dispersion X-ray spectroscopy. SPSS (Statistical Package for Social Sciences) version 21.0 was used to analyze the results. The data were analyzed for probability distribution using the Kolmogorov-Smirnov test, and a non-parametric test of significance was applied. An inter-group comparison was done using the Mann-Whitney U test. A statistically significant increase was observed in the bactericidal action of BN-coated discs compared to uncoated discs against S. mutans, but no statistically significant difference was found against F. nucleatum.

Application of survival analysis to model proliferation likelihood of Escherichia coli biofilm following laser-induced hyperthermia treatment.

Eighty percent of bacterial infections associated with living tissue and medical devices are linked to drug-resistant biofilms, leading to lengthy and costly recoveries. Laser-induced hyperthermia can disrupt cell proliferation within biofilms and increase susceptibility to antibiotics. However, there can be bacterial survival differences dependent upon laser irradiation times, and prolonged time at elevated temperature can damage healthy tissue. The objective of this study was to use survival analysis to model the impact of temperature increases on reducing viable biofilm bacteria. In vitro biofilms of Escherichia coli were grown on silicone discs or silicone doped with photothermal poly(3,4-ethylenedioxythiophene) hydrate (PEDOT) nanotubes, and subjected to laser-induced hyperthermia, using a 3W continuous wave laser at 800nm for varying times. The number of colony forming units per milliliter (CFU/mL) and maximum temperature were measured after each trial. Survival analysis was employed to estimate bacterial cell proliferation post-treatment to provide a quantitative framework for future studies evaluating photothermal inactivation of bacterial biofilms. The results demonstrate the first application of survival analysis for predicting the likelihood of bacterial cell proliferation based on temperature.

Mechanism of trehalose-enhanced metabolism of heterotrophic nitrification-aerobic denitrification community under high-salt stress

Heterotrophic nitrification-aerobic denitrification (HN-AD) bacteria are aerobic microorganisms that can remove nitrogen under high-salt conditions, but their performance in practical applications are not satisfactory. As a compatible solute, trehalose helps microorganisms to cope with high salt stress by participating in the regulation of cellular osmotic pressure, and plays an important role in promoting the nitrogen removal efficiency of microbial populations in the high-salt environment. We investigated the mechanism of exogenous-trehalose-enhanced metabolism of HN-AD community under high-salt stress by starting up a membrane aerobic biofilm reactor (MABR) to enrich HN-AD bacteria, and designed a C150 experimental group with 150 μmol/L trehalose addition and a C0 control group without trehalose. The reactor performance and the community structure showed that NH4+-N, total nitrogen (TN) and chemical oxygen demand (COD) removal efficiency were increased by 29.7%, 28.0% and 29.1%, respectively. The total relative abundance of salt-tolerant HN-AD bacteria (with Acinetobacter and Pseudofulvimonas as the dominant genus) in the C150 group reached 66.8%, an 18.2% increase compared with that of the C0 group. This demonstrated that trehalose addition promoted the enrichment of salt-tolerant HN-AD bacteria in the high-salt environment to enhance the nitrogen removal performance of the system. In-depth metabolomics analysis showed that the exogenous trehalose was utilized by microorganisms to improve proline synthesis to increase resistance to high-salt stress. By regulating the activity of cell proliferation signaling pathways (cGMP-PKG, PI3K-Akt), phospholipid metabolism pathway and aminoacyl-tRNA synthesis pathway, the abundances of phosphoethanolamine, which was one of the glycerophospholipid metabolites, and purine and pyrimidine were up-regulated to stimulate bacterial aggregation and cell proliferation to promote the growth of HN-AD bacteria in the high-salt environment. Meanwhile, the addition of trehalose accelerated the tricarboxylic acid (TCA) cycle, which might provide more electron donors and energy to the carbon and nitrogen metabolisms of HN-AD bacteria and promote the nitrogen removal performance of the system. These results may facilitate using HN-AD bacteria in the treatment of high-salt and high-nitrogen wastewater.

Lacritin Bactericidal Peptide N‐104 Targeting of Inner Membrane Transporters FeoB and PotH (SpuG) Individually Absent in N‐104 Resistant Strains of Human Opportunistic Pathogen, P. aeruginosa PA14

Through an unbiased screen of the E. coli Keio collection of 3,985 nonessential gene knockouts, we have discovered that inner membrane putrescine and ferrous iron transporters PotH and FeoB each play roles in the bactericidal mechanism of tear lacritin peptide ‘N‐104’ ‐ possibly involving outer‐membrane translocation by lipoprotein YaiW with which it binds and when absent confers N‐104 resistance. The results were confirmed in the human opportunistic pathogen, P. aeruginosa PA14, and in a robust C. elegans‐based liquid infection assay. Does periplasmic N‐104 directly or indirectly target PotH and/or FeoB? His‐tagged FeoB (P. aeruginosa) and PotH (E. coli) extracted in lysis buffer containing 2% Dodecyl‐b‐D‐maltopyranoside were purified on Ni‐Sepharose columns, concentrated on 50 kDa (FeoB) or 30 kDa (PotH) Amicon cutoff membranes, and then added in equal amounts in 150 mM NaCl column buffer to SulfoLink® immobilized Cys‐N‐104 or to negative control Cys‐C‐95 columns. After overnight incubation at 4°C and collection of the flow through, columns were washed with 25 column volumes of 150 mM KCl before elution via a gradient of column buffer containing 300, 500, or 1000 mM KCl. Whereas FeoB and PotH were detected only in the flow through off of C‐95, 500 mM KCl was required for elution off of N‐104. PotH inwardly transports putrescine, the predominant polyamine in bacterial cells (10 ‐ 30 mM) that is essential for optimal bacterial cell growth and proliferation. FeoB is the major mediator of ferrous iron uptake in P. aeruginosa, E. coli, H. pylori, and some other species, and is a well‐recognized virulence factor. Given that none of those proteins are essential for the bacterial survival, we hypothesize that N‐104 might either disturb putrescine or ferrous iron regulation, or employ each to trigger programmed cell death via uncharacterized YbdM predicted to have transcription regulatory region activity also discovered to bind N‐104, and when absent confers N‐104 resistance. This study uncovers new virulence factors, and a novel method of bacterial cell death by a natural peptide component of human tears and apparently of plasma.

Synthesis, anti-TB activities, and molecular docking studies of 4-(1,2,3-triazoyl)arylmethanone derivatives.

Infectious diseases such as tuberculosis (TB) are leading causes of human death. Antibiotics are effective molecules to combat bacterial infections by affecting the processes required for bacterial cell growth and proliferation. The development of new antibiotics has become an important issue as overdosed or incorrect use of antibiotic lead to the development of antibiotic resistance. In this study, a new series of 4-(1,2,3-triazoyl)arylmethanone derivatives has been synthesized using the one-pot Copper-​Catalyzed Oxidative Cross-​Dehydrogenative Coupling​/Oxidative Cycloaddition strategy to overcome the aforementioned problems. New compounds were characterized by using spectroscopic techniques (1 H, 13 C-APT-NMR, FT-IR, and HRMS-TOF). In vitro antimycobacterial activities of the arylmethanone derivatives against the Mycobacterium tuberculosis H37 Rv standard strain were examined using the resazurin microplate method in the presence of streptomycin and rifampycin as standard medicines. Bioactive assays demonstrated promising results that some of the synthesized 4-(1,2,3-triazoyl)arylmethanone derivatives exhibited good anti-TB activities. Notably, compounds 6b, 6f, and 6g gave the most potent efficiency with minimum inhibitory concentration values of 4 μg/ml (12.8, 11.7, and 12.8 μΜ, respectively). Among the synthesized compounds, the cytotoxicity measurements of the 6b, 6f, 6g, 6d, and 6v derivatives were screened and it was found that the 6f derivative did not show any cytotoxicity. Molecular docking analyses are utilized to identify the binding mode and the key interactions between target compounds and the ligand-binding site of M. tuberculosis enoyl-acyl carrier protein reductase enzyme (MtInhA, EC 1.3.1.9). The docking results were in agreement with the in vitro results, which confirm the synthesized ligands bind to MtInha with moderate to low affinity.

Antibacterial behavior of oxynitride glasses as a glassy grain boundary phase for silicon nitride‐based ceramics

AbstractSilicon nitride‐based ceramics have provided significant advantages due to their high chemical resistance, high elastic modulus, and combination of hardness and fracture toughness (depending on self‐reinforcement). Over the past two decades, a significant amount of interest has been generated for the bio‐applications of these materials. However, the effect of the grain boundary phase on such applications is still not very well understood. In this study, the effect of different cations on biological (such as antibacterial and cytocompatibilty) and material properties (like wetting angles and isoelectric points [IEP]) of oxynitride glasses, mimicking the grain boundary phase in Si3N4 and SiAlON ceramics, were investigated. Results revealed that the antibacterial behavior and mammalian cell viability were inversely correlated in glasses with rare‐earth cation additions. Ca was the best cation when the two properties (bacterial response and cell proliferation) were considered together, and, thus should be further studied for a wide range of applications.

DNA and Polyphosphate in Directed Proteolysis for DNA Replication Control.

The strict control of bacterial cell proliferation by proteolysis is vital to coordinate cell cycle processes and to adapt to environmental changes. ATP-dependent proteases of the AAA + family are molecular machineries that contribute to cellular proteostasis. Their activity is important to control the level of various proteins, including those that are essential for the regulation of DNA replication. Since the process of proteolysis is irreversible, the protease activity must be tightly regulated and directed toward a specific substrate at the exact time and space in a cell. In our mini review, we discuss the impact of phosphate-containing molecules like DNA and inorganic polyphosphate (PolyP), accumulated during stress, on protease activities. We describe how the directed proteolysis of essential replication proteins contributes to the regulation of DNA replication under normal and stress conditions in bacteria.

Bacterial cell proliferation: from molecules to cells.

ABSTRACTBacterial cell proliferation is highly efficient, both because bacteria grow fast and multiply with a low failure rate. This efficiency is underpinned by the robustness of the cell cycle and its synchronization with cell growth and cytokinesis. Recent advances in bacterial cell biology brought about by single-cell physiology in microfluidic chambers suggest a series of simple phenomenological models at the cellular scale, coupling cell size and growth with the cell cycle. We contrast the apparent simplicity of these mechanisms based on the addition of a constant size between cell cycle events (e.g. two consecutive initiation of DNA replication or cell division) with the complexity of the underlying regulatory networks. Beyond the paradigm of cell cycle checkpoints, the coordination between the DNA and division cycles and cell growth is largely mediated by a wealth of other mechanisms. We propose our perspective on these mechanisms, through the prism of the known crosstalk between DNA replication and segregation, cell division and cell growth or size. We argue that the precise knowledge of these molecular mechanisms is critical to integrate the diverse layers of controls at different time and space scales into synthetic and verifiable models.

Tol-Pal System and Rgs Proteins Interact to Promote Unipolar Growth and Cell Division in Sinorhizobium meliloti.

Sinorhizobium meliloti is an alphaproteobacterium belonging to the Rhizobiales Bacteria from this order elongate their cell wall at the new cell pole, generated by cell division. Screening for protein interaction partners of the previously characterized polar growth factors RgsP and RgsM, we identified the inner membrane components of the Tol-Pal system (TolQ and TolR) and novel Rgs (rhizobial growth and septation) proteins with unknown functions. TolQ, Pal, and all Rgs proteins, except for RgsE, were indispensable for S. meliloti cell growth. Six of the Rgs proteins, TolQ, and Pal localized to the growing cell pole in the cell elongation phase and to the septum in predivisional cells, and three Rgs proteins localized to the growing cell pole only. The putative FtsN-like protein RgsS contains a conserved SPOR domain and is indispensable at the early stages of cell division. The components of the Tol-Pal system were required at the late stages of cell division. RgsE, a homolog of the Agrobacterium tumefaciens growth pole ring protein GPR, has an important role in maintaining the normal growth rate and rod cell shape. RgsD is a periplasmic protein with the ability to bind peptidoglycan. Analysis of the phylogenetic distribution of the Rgs proteins showed that they are conserved in Rhizobiales and mostly absent from other alphaproteobacterial orders, suggesting a conserved role of these proteins in polar growth.IMPORTANCE Bacterial cell proliferation involves cell growth and septum formation followed by cell division. For cell growth, bacteria have evolved different complex mechanisms. The most prevalent growth mode of rod-shaped bacteria is cell elongation by incorporating new peptidoglycans in a dispersed manner along the sidewall. A small share of rod-shaped bacteria, including the alphaproteobacterial Rhizobiales, grow unipolarly. Here, we identified and initially characterized a set of Rgs (rhizobial growth and septation) proteins, which are involved in cell division and unipolar growth of Sinorhizobium meliloti and highly conserved in Rhizobiales Our data expand the knowledge of components of the polarly localized machinery driving cell wall growth and suggest a complex of Rgs proteins with components of the divisome, differing in composition between the polar cell elongation zone and the septum.

Polyphosphate induces the proteolysis of ADP-bound fraction of initiator to inhibit DNA replication initiation upon stress in Escherichia coli.

The decision whether to replicate DNA is crucial for cell survival, not only to proliferate in favorable conditions, but also to adopt to environmental changes. When a bacteria encounters stress, e.g. starvation, it launches the stringent response, to arrest cell proliferation and to promote survival. During the stringent response a vast amount of polymer composed of phosphate residues, i.e. inorganic polyphosphate (PolyP) is synthesized from ATP. Despite extensive research on PolyP, we still lack the full understanding of the PolyP role during stress. It is also elusive what is the mechanism of DNA replication initiation arrest in starved Escherichia coli cells. Here, we show that during stringent response PolyP activates Lon protease to degrade selectively the replication initiaton protein DnaA bound to ADP, but not ATP. In contrast to DnaA-ADP, the DnaA-ATP does not interact with PolyP, but binds to dnaA promoter to block dnaA transcription. The systems controlling the ratio of nucleotide states of DnaA continue to convert DnaA-ATP to DnaA-ADP, which is proteolysed by Lon, thereby resulting in the DNA replication initiation arrest. The uncovered regulatory mechanism interlocks the PolyP-dependent protease activation with the ATP/ADP cycle of dual-functioning protein essential for bacterial cell proliferation.

Tribological properties of microporous polydimethylsiloxane (PDMS) surfaces under physiological conditions

Textured biomaterials have been extensively used in biomedical engineering to modulate mammalian and bacterial cell adhesion and proliferation, implant integration with human body and infection prevention. However, the tribological implications of texturing under wet physiological conditions have not been well quantified. This study aimed to characterize the tribological properties of micropore-textured polydimethylsiloxane (PDMS) under physiological conditions and investigate the effect of adsorbed lubricious molecules on friction. In this study, untextured and micropore-textured PDMS surfaces were slid against curved smooth glass surfaces under the contact pressures of 10–400 kPa, sliding speeds of 0.1–5 mm/s in aqueous solutions with the viscosity of 1–1000 mPa·s. Reconstituted human whole saliva (RHWS) at pH 7 and porcine gastric mucin (PGM) at both pH 2 and 7 were used as lubricious coatings on PDMS. While the micropore-texturing delayed the transition of lubrication regimes, it increased the coefficient of friction (COF). Although RHWS and PGM coatings decreased the COF significantly, the protein coatings could not help the COF of micropore-textured surfaces getting lower than that of untextured surfaces. The results suggest textured polymeric surfaces could generate larger friction under physiological conditions and lead to a higher chance of inflammation near the implants.

Lactobacillus casei fermentation towards xylooligosaccharide (XOS) obtained from coffee peel enzymatic hydrolysate

Abstract Coffee peel waste contains fibers including xylan, a polymer that constitutes hemicelluloses. Xylan can be extracted from coffee peel and used for xylooligosaccharide (XOS) production. XOS is an oligomer that has the potentials as a prebiotic. XOS production could be carried out by enzymatic hydrolysis using endo-β-1,4- d -xylanase. In this research, the XOS from coffee peel was investigated for its prebiotic potential on the growth of Lactobacillus casei (L.casei) in-vitro. The assay was carried out by adding various concentrations of XOS to the bacterial culture media under different incubation times. L. casei growth was calculated based on the formed bacterial colonies log CFU/mL. Addition of 20% XOS to 10 mL of L. casei growth media showed the best result at 12 h with 8.75 log CFU/mL. Increased bacterial colonies proved that XOS in fermented media was beneficial for the bacteria, resulting in bacterial cell proliferation. Other parameters observed in this study were the decreased pH value, the reduced XOS level and the increased content of organic acids in the bacterial culture media.

Biodegradation of tannery dye effluent using Fenton's reagent and bacterial consortium: A biocalorimetric investigation

The impact caused by dye effluent discharge on the environment is well known. The study explores a hybrid method of combining Fenton oxidation with biological treatment by a defined bacterial consortium for the biodegradation of an effluent containing toxic azo dye (acid blue 113). In actual treatment process, the fluctuation in toxic load and presence of other dyeing chemical inhibits the activity of the bacterial consortium. An effective pre-treatment of effluent would ensure the optimal degradation irrespective of its initial load. The pre-treatment of dye effluent with Fenton (H2O2 & Fe2+), considerably reduced the dye concentration by 40% and a maximum dye degradation of 85% (i.e., 45% by biodegradation) was achieved in shake flask. The biodegradation process was investigated in a bioreaction calorimeter (BioRc1e), the heat profile, bioenergetics data along with CER (Carbon dioxide emission rate) and OUR (Oxygen uptake rate) provided vital information for the effective commercial scale up. Enhanced degradation of up to 97% was achieved in BioRc1, the CER and OUR profile follows the power-time profile alluding that the heat generated is the resultant effect of bacterial metabolic activity. In real dye bath effluent the Fenton pre-oxidized biodegradation reaction showed a degradation efficacy of 89.5% and considerable COD reduction of 93.7%. Fluorescence-activated cell sorting (FACS) analysis revealed a better bacterial cell proliferation in pre-treated experiment and gas chromatography and mass spectrum analysis were used for prediction of metabolites. The unique combination of Fenton and the microbial consortia is a competitive technology for industrial effluent treatment processes.

1,2,4-Triazole-quinoline/quinolone hybrids as potential anti-bacterial agents

Bacterial infections, caused predominately by Gram-positive and Gram-negative organisms, are proliferation of harmful strains of bacteria on or inside the body. Hospital-acquired and community-acquired bacterial infections have already put a heavy burden on the global health system. Antibiotics can disrupt the processes necessary for bacterial cell growth and proliferation, are effective weapons to fight against bacterial infections. However, the overuse and misuse of antibiotics have led to a rise in antibiotic resistance, creating an urgent need to develop novel antibiotics. 1,2,4-Triazole-quinoline/quinolone hybrids possess a broad spectrum of chemotherapeutic properties, also demonstrated promising anti-bacterial activities against both drug-sensitive and drug-resistant bacteria. This review covers the recent advances of 1,2,4-triazole-quinoline/quinolone hybrids as potential anti-bacterial agents. The structure-activity relationship (SAR) is also discussed for further rational development of 1,2,4-triazole hybrids higher potency against both drug-sensitive and drug-resistant pathogens.

Comprehensive review on the anti-bacterial activity of 1,2,3-triazole hybrids

Bacterial infections, caused predominately by Gram-positive and Gram-negative organisms, are proliferation of harmful strains of bacteria on or inside the body. Hospital-acquired and community-acquired bacterial infections have already put a heavy burden on the global health system. Antibiotics which can disrupt the processes necessary for bacterial cell growth and proliferation are effective weapons to fight against bacterial infections. However, the overuse and misuse of antibiotics have led to a rise in antibiotic resistance, creating an urgent need to develop novel antibiotics. 1,2,3-Triazole hybrids possess a broad spectrum of chemotherapeutic properties, also demonstrated promising in vitro and in vivo anti-bacterial activities. This review covers the recent (2000–2019) advances of 1,2,3-triazole hybrids as potential anti-bacterial agents. The structure-activity relationship (SAR) is also discussed for further rational development of 1,2,3-triazole hybrids with higher potency against both drug-sensitive and drug-resistant pathogens.

Relevance of Topographic Parameters on the Adhesion and Proliferation of Human Gingival Fibroblasts and Oral Bacterial Strains.

Dental implantology allows replacement of failing teeth providing the patient with a general improvement of health. Unfortunately not all reconstructions succeed, as a consequence of the development of infections of bacterial origin on the implant surface. Surface topography is known to modulate a differential response to bacterial and mammalian cells but topographical measurements are often limited to vertical parameters. In this work we have extended the topographical measurements also to lateral and hybrid parameters of the five most representative implant and prosthetic component surfaces and correlated the results with bacterial and mammalian cell adhesion and proliferation outcomes. Primary human oral gingival fibroblast (gum cells) and the bacterial strains: Streptococcus mutans, Streptococcus sanguinis and Aggregatibacter actinomycetemcomitans, implicated in infectious processes in the oral/implant environment were employed in the presence or absence of human saliva. The results confirm that even though not all the measured surface is available for bacteria to adhere, the overall race for the surface between cells and bacteria is more favourable to the smoother surfaces (nitrided, as machined or lightly acid etched) than to the rougher ones (strong acid etched or sandblasted/acid etched).