Cell Wall Of Bacteria Research Articles

Harnessing the combined effect of antivirulence agent trans-chalcone with bactericidal curcumin against sortase A enzyme to tackle Gram-positive bacterial infections.

Gram-positive bacteria are responsible for a wide range of infections in humans. In most Gram-positive bacteria, sortase A plays a significant role in attaching virulence factors to the bacteria's cell wall. These cell surface proteins play a significant role in virulence and pathogenesis. Even though antibiotics are available to treat these infections, there is a continuous search for an alternative strategy due to an increase in antibiotic resistance. Thus, using anti-sortase drugs to combat these bacterial infections may be a promising approach. Here, we describe a method for targeting Gram-positive bacterial infection by combining curcumin and trans-chalcone as sortase A inhibitors. We have used curcumin and trans-chalcone alone and in combination as a sortase A inhibitor. We have seen ~78%, ~43%, and ~94% inhibition when treated with curcumin, trans-chalcone, and a combination of both compounds, respectively. The compounds have also shown a significant effect on biofilm formation, IgG binding, protein A recruitment, and IgG deposition. We discovered that combining curcumin and trans-chalcone is more effective against Gram-positive bacteria than either compound alone. The present work demonstrated that a combination of these natural compounds could be used as an antivirulence therapy against Gram-positive bacterial infection.

Discovery of new quaternized norharmane dimers as potential anti-MRSA agents

IntroductionMethicillin-resistant Staphylococcus aureus (MRSA)-caused infections greatly threaten public health. The discovery of natural-product-based anti-MRSA agents for treating infectious diseases has become one of the current research focuses. ObjectivesThis study aims to identify promising anti-MRSA agents with a clear mechanism based on natural norharmane modified by quaternization or dimerization. MethodsA total of 32 norharmane analogues were prepared and characterized. Their antibacterial activities and resistance development propensity were tested by the broth double-dilution method. Cell counting kit-8 and hemolysis experiments were used to assess their biosafety. The plasma stability, bactericidal mode, and biofilm disruption effects were examined by colony counting and crystal violet staining assays. Fluorescence microscopy, metabolomic analysis, docking simulation and spectra titration revealed its anti-MRSA mechanisms. The mouse skin infection model was used to investigate the in vivo efficacy. ResultsCompound 5a was selected as a potential anti-MRSA agent, which exhibited potent anti-MRSA activity in vitro and in vivo, low cytotoxicity and hemolysis under an effective dose. Moreover, compound 5a showed good stability in 50% plasma, a low tendency of resistance development and capabilities to disrupt bacterial biofilms. The mechanism studies revealed that compound 5a could inhibit the biosynthesis of bacteria cell walls, damage the membrane, disturb energy metabolism and amino acid metabolism pathways, and interfere with protein synthesis and nucleic acid function. ConclusionsThese results suggested that compound 5a is a promising candidate for combating MRSA infections, providing valuable information for further exploiting a new generation of therapeutic antibiotics.

Calcium ions enhanced freeze-drying and spray-drying resistance of Lactiplantibacillus plantarum LIP-1 by regulation of cell wall surface proteins and related enzymes expression

The cell wall of lactic acid bacteria maintain the osmotic pressure inside and outside the cell as well as the inherent morphology of the strain. During the drying process, cell wall is the first site to be damaged. Still, little research has been done to reduce the damage of cell wall during the drying process. Therefore, this study explored the protective effect of calcium ions (Ca2+) on the cell wall of Lactiplantibacillus plantarum LIP-1 during freeze- and spray-drying. Furthermore, the mechanism behind the improved stress resistance of bacteria due to Ca2+ has also been investigated. The results showed that addition of 0.50 mmol/L Ca2+ to the culture medium significantly improved the freeze-drying and spray-drying survival rates of the strain (P < 0.05). It was found that Ca2+ significantly increases the content of surface proteins. Due to the enhanced cell wall proteinase (CEP) activity, the surface proteins are anchored to the cell wall, thereby reducing the cell wall damage in strain during the drying process and improving survival rate during drying and increasing storage stability at room temperature.

Exploring the therapeutic potential of recombinant human lysozyme: a review on wound management system with antibacterial.

Lysozyme, a natural antibacterial enzyme protein, possesses the ability to dissolve the cell walls of Gram-positive bacteria, demonstrating broad-spectrum antibacterial activity. Despite its significant potential in treating wound infections and promoting wound healing, its widespread clinical application has yet to be realized. Current research is primarily focused on carrier-based delivery systems for lysozyme. In this review, we discuss four delivery systems that can be employed for lysozyme in wound healing treatment, specifically hydrogels, nanofilms, electrospun fibrous membranes, and modified-lysozyme composite systems. These systems not only enhance the stability of lysozyme but also enable its controlled and sustained release at wound sites, potentially overcoming some of the challenges associated with its direct application. Lastly, we delve into the perspectives and challenges related to the use of these delivery systems, hoping to spur further research and innovation in this promising field.

Tannin derived from Uncaria gambir Roxb. as potential Enterococcus faecalis UDP-N-Acetylenolpyruvoyl-Glucosamine Reductase (Mur Benzyme) inhibitor: In-silico antibacterial study

The high prevalence of pulp and periapical disease is an important problem for dental and oral health in dentistry. Treatment of pulp and periapical disease is generally carried out utilizing root canal treatment, but the results of the treatment are often not as expected. Enterococcus faecalis is a bacterium that plays a role in the failure of root canal treatment. E. faecalis are Gram-positive bacteria that use the Muramidase B (MurB) enzyme in the biosynthesis of peptidoglycan, which will build bacteria cell walls and play an important role in protecting bacteria. Gambir (Uncaria gambir Roxb.) is an herbal plant that is used in the field of medicine and contains tannin compounds that have antibacterial activity. The purpose of this study was to predict the antibacterial activity of Gambir extracts against the MurB enzyme compared with chlorhexidine through in silico approach. The Mur B enzyme was obtained from the Protein Data Bank (PDB), and the structure of the compound (tannins and chlorhexidine) was obtained from Pubchem. Using Auto dock tools from Pyrx software for docking between the two compounds (tannin and chlorhexidine) with the MurB enzyme, and visualize using Pymol and 3D analysis using Biovia. The results showed that tannins had a binding affinity of more than -7.4 kcal.mol-1 to the MurB enzyme and chlorhexidine had a higher binding affinity than tannins. Both tannins and chlorhexidine have hydrogen bonds with the same three amino acids, that is ARG 159, GLY 123, and ASN 233. The results showed that tannins interacted with the MurB enzyme and could inhibit the action of the MurB enzyme.

Open roads and bridge: Preservation of fresh beef by a packaging film constructed from photosensitizing bacterial cellulose

Food packaging is now widely used in everyday life to protect food from certain environmental factors. In this work, we have successfully prepared a bacterial cellulose/chitosan-TPE-COOH composite film (BC/CS-TPE), which can achieve broad-spectrum killing of bacteria through a variety of antibacterial mechanisms and ensure the freshness of the beef. In this complex film, CS acts as “advance team”, responsible for breaking through the cell wall or outer membrane of bacteria, while the reactive oxygen species produced by photosensitizer under irradiation attacks bacteria, further increasing the destructive effect on the bacterial cell membrane. This allows the film to have outstanding antibacterial properties that can kill 108 CFU/mL pathogens in 10 min. At the same time, cell experiments and hemolysis experiments proved that the film has good biocompatibility. Therefore, BC/CS-TPE film, as the efficient functional food packaging film, has a broad future application prospect.

In vitro antibacterial activity of dinuclear thiolato-bridged ruthenium(II)-arene compounds.

The antibacterial activity of 22 thiolato-bridged dinuclear ruthenium(II)-arene compounds was assessed in vitro against Escherichia coli, Streptococcus pneumoniae, and Staphylococcus aureus. None of the compounds efficiently inhibited the growth of the three E. coli strains tested, and only compound 5 exhibited a medium activity against this bacterium [MIC (minimum inhibitory concentration) of 25 µM]. However, a significant antibacterial activity was observed against S. pneumoniae, with MIC values ranging from 1.3 to 2.6 µM for compounds 1-3, 5, and 6. Similarly, compounds 2, 5-7, and 20-22 had MIC values ranging from 2.5 to 5 µM against S. aureus. The tested diruthenium compounds have a bactericidal effect significantly faster than that of penicillin. Fluorescence microscopy assays performed on S. aureus using the BODIPY-tagged diruthenium complex 15 showed that this type of metal compound enters the bacteria and does not accumulate in the cell wall of gram-positive bacteria. Cellular internalization was further confirmed by inductively coupled plasma mass spectrometry experiments. The nature of the substituents anchored on the bridging thiols and the compounds molecular weight appears to significantly influence the antibacterial activity. Thus, if overall a decrease of the bactericidal effect with the increase of compounds' molecular weight is observed, however, the complexes bearing larger benzo-fused lactam substituents had low MIC values. This first antibacterial activity screening demonstrated that the thiolato-diruthenium compounds exhibit promising activity against S. aureus and S. pneumoniae and deserve to be considered for further studies. IMPORTANCE The in vitro assessment of diruthenium(II)-arene compounds against Escherichia coli, Streptococcus pneumoniae, and Staphylococcus aureus showed a significant antibacterial activity of some compounds against S. pneumoniae, with minimum inhibitory concentration (MIC) values ranging from 1.3 to 2.6 µM, and a medium activity against E. coli, with MIC of 25 µM. The nature of the substituents anchored on the bridging thiols and the compounds molecular weight appear to significantly influence the antibacterial activity. Fluorescence microscopy showed that these ruthenium compounds enter the bacteria and do not accumulate in the cell wall of gram-positive bacteria. These diruthenium(II)-arene compounds exhibit promising activity against S. aureus and S. pneumoniae and deserve to be considered for further studies, especially the compounds bearing larger benzo-fused lactam substituents.

Protein secretion zones during overexpression of amylase within the Gram-positive cell wall

BackgroundWhereas the translocation of proteins across the cell membrane has been thoroughly investigated, it is still unclear how proteins cross the cell wall in Gram-positive bacteria, which are widely used for industrial applications. We have studied the secretion of α-amylase AmyE within two different Bacillus strains, B. subtilis and B. licheniformis.ResultsWe show that a C-terminal fusion of AmyE with the fluorescent reporter mCherry is secreted via discrete patches showing very low dynamics. These are visible at many places within the cell wall for many minutes. Expression from a high copy number plasmid was required to be able to see these structures we term “secretion zones”. Zones corresponded to visualized AmyE activity on the surface of cells, showing that they release active enzymes. They overlapped with SecA signals but did not frequently co-localize with the secretion ATPase. Single particle tracking showed higher dynamics of SecA and of SecDF, involved in AmyE secretion, at the cell membrane than AmyE. These experiments suggest that SecA initially translocates AmyE molecules through the cell membrane, and then diffuses to a different translocon. Single molecule tracking of SecA suggests the existence of three distinct diffusive states of SecA, which change during AmyE overexpression, but increased AmyE secretion does not appear to overwhelm the system.ConclusionsBecause secretion zones were only found during the transition to and within the stationary phase, diffusion rather than passive transport based on cell wall growth from inside to outside may release AmyE and, thus, probably secreted proteins in general. Our findings suggest active transport through the cell membrane and slow, passive transition through the cell wall, at least for overexpressed proteins, in bacteria of the genus Bacillus.

An update on our understanding of Gram-positive bacterial membrane vesicles: discovery, functions, and applications.

Extracellular vesicles (EVs) are nano-sized particles released from cells into the extracellular environment, and are separated from eukaryotic cells, bacteria, and other organisms with cellular structures. EVs alter cell communication by delivering their contents and performing various functions depending on their cargo and release into certain environments or other cells. The cell walls of Gram-positive bacteria have a thick peptidoglycan layer and were previously thought to be unable to produce EVs. However, recent studies have demonstrated that Gram-positive bacterial EVs are crucial for health and disease. In this review, we have summarized the formation, composition, and characteristics of the contents, resistance to external stress, participation in immune regulation, and other functions of Gram-positive bacterial EVs, as well as their application in clinical diagnosis and treatment, to provide a new perspective to further our understanding of Gram-positive bacterial EVs.

Microbial mechanisms of regulation of the activity of nuclear transcription factor NF-kB1

Nuclear transcription factor NF-kB1 is a regulator of the expression of immune response genes, apoptosis, inflammatory reactions and cell proliferation. Microorganisms are able to change the activity of the nuclear transcription factor, which allows them to modulate the immune response of the macroorganism and/or have a pathogenic effect on organs and tissues. The aim of the study is to systematize data on microbial molecular factors regulating the transcription nuclear factor NFkB-1. The review describes microbial molecules, the mechanisms of their action on the nuclear transcription factor NF-kB1. The A52R protein of the smallpox vaccine virus acts as a homologue of MyD88, the Yersinia YopP/J protein acetylates the IKKß subunit, thereby inhibiting kB kinase (IKK) and preventing the activation of the nuclear factor NFkB. The EBNA1 protein of the Epstein-Barr virus is a "stop signal" for the proteasome, so blocking proteolysis disrupts the presentation of virus antigens on MHC I and the overall immune response. The OspG protein of microorganisms of the genus Shigella prevents ubiquitination, and also inhibits the degradation of phosphorylated IKKß, which disrupts the activation of NFkB-1. Enteropathogenic Escherichia coli (EPEC) produces three effectors to inhibit the function of NFkB. Two of these effectors, NleB and NleE block signaling at the level of TGF-beta-activated kinase 1 or IKKß kinase, the third NleH protein binds to the RPS3 (ribosomal protein S3) cofactor of the NFkB factor and suppresses the transcription of many genes. The components of bacterial cells – lipopolysaccharides of the cell walls of gram-negative bacteria, representatives of the Enterobacteriaceae family, participate in modulating the activity of the transcription factor. This polymer affects the presentation genes of MHC class I and II antigens, the death receptor, IL-6 signaling, IFN-γ signaling and the P38 signaling pathway. Conclusion. Protein and non-protein substances of microorganisms, components of bacterial cell structures are molecules that have a multidirectional effect on the activity of proteasomes that regulate inflammatory and immune responses in the macroorganism.

Clinical Value Of Intravenous Fosfomycin Combinations

Aims:Due to the increasing number of Multi-Drug Resistance (MDR) and Extensively Drug Resistant (XDR) pathogens and the difficulties in developing new antibiotics, some combinations are being tried. Fosfomycin is a phosphonic acid derivative UDP-N-acetyl glucosamine (MurA) inhibitor. Fosfomycin inhibits bacteria cell wall synthesis in its first step. It acts against both gram-positive and gram-negative Multi-Drug Resistance (MDR) and Extensive Drug-Resistant (XDR) bacteria. It prevents bacterial invasion into the urinary system and respiratory tract epithelİum. It was aimed to evaluate the clinical and microbiological response rates of intravenous fosfomycin treatment in gram-negative MDR and XDR bacterial infections in this study.&#x0D; Methods: Total 77 patients from four different centers where used intravenous fosfomycin treatment were involved to the study. It was evaluated clinical and microbiological response in 72 hours after the beginning of treatment and at the end of treatment. Clinical and microbiological response have been evaluated in the study population. &#x0D; Results: While 41 of the patients were female (53.2%), 36 were male (46.8%), it is found that their mean age was 60.5. Clinical response rates 72 hours after the initiation of treatment and at the end of treatment were 46 (59.7%) and 45 (58.4%), respectively. Microbiological eradication rate was achieved in 40 (51.9%) patients in the first 72 hours and in 39 (50.6%) patients at the end of the treatment. Clinical response and microbiological eradication rates after seventy two hours and at the end of treatment were found to be similar with together. &#x0D; Conclusions: As a result, fosfomycin may be an alternative in combination therapy due to its low side effect profile and lack of drug interaction in the treatment of MDR and XDR pathogens.

Identification and characterization of endo-α-, exo-α-, and exo-β-d-arabinofuranosidases degrading lipoarabinomannan and arabinogalactan of mycobacteria

The cell walls of pathogenic and acidophilic bacteria, such as Mycobacterium tuberculosis and Mycobacterium leprae, contain lipoarabinomannan and arabinogalactan. These components are composed of d-arabinose, the enantiomer of the typical l-arabinose found in plants. The unique glycan structures of mycobacteria contribute to their ability to evade mammalian immune responses. In this study, we identified four enzymes (two GH183 endo-d-arabinanases, GH172 exo-α-d-arabinofuranosidase, and GH116 exo-β-d-arabinofuranosidase) from Microbacterium arabinogalactanolyticum. These enzymes completely degraded the complex d-arabinan core structure of lipoarabinomannan and arabinogalactan in a concerted manner. Furthermore, through biochemical characterization using synthetic substrates and X-ray crystallography, we elucidated the mechanisms of substrate recognition and anomer-retaining hydrolysis for the α- and β-d-arabinofuranosidic bonds in both endo- and exo-mode reactions. The discovery of these d-arabinan-degrading enzymes, along with the understanding of their structural basis for substrate specificity, provides valuable resources for investigating the intricate glycan architecture of mycobacterial cell wall polysaccharides and their contribution to pathogenicity.

Histidine-inspired polyacrylonitrile-based adsorbent with excellent hemocompatibility for the simultaneous removal of bacteria and endotoxin in septic blood

Endotoxins (LPS) are components of the cell wall of Gram-negative bacteria that are released when bacterial cell membrane is destroyed, the bacteria and the released LPS have led to serious diseases such as sepsis and septic shock. Histidine functionalized adsorbents have been used to remove LPS, however, the present hemoperfusion adsorbents have drawbacks such as inadequate LPS adsorption capability, high cost of raw material, and so on. Inspired by the structure of histidine and incorporated antibacterial molecules, we synthesize allylamine-modified polyacrylonitrile (PAD)/poly (imidazolium bromide) (PMIBr) composite (PAI) microspheres as hemoperfusion adsorbents. The PAI microspheres show excellent antibacterial ability with high killing efficiency of 98.8% against S. aureus and 95.4% against E. coli. In addition, the adsorption capacity of the microspheres for LPS in PBS is 433.5 EU/g within 3 h, and the LPS concentration could also be reduced from 7.34 EU/mL to below 0.5 EU/mL in the plasma environment. The PAI microspheres exhibit outstanding blood compatibility, antibacterial property and endotoxin removal capability, which have great potential in the treatment of sepsis patients.

Highly adhesive and catalytic VOxC nanosheets with strong antibacterial activity

Peroxidase-like nanozymes represent fascinating agents that can treat bacterial infections by oxidative attack. Challengingly, many antibacterial nanozymes only perform well at high concentrations because the low affinity to attach on bacterial surface, short lifetime and working distance for hydroxyl radicals largely limit the applications of antibacterial nanozymes. The potential safety/toxicity should be also considered under an exposure of high concentrations of nanomaterials. In this work, we proposed a “Melee attack” strategy to strikingly enhance antibacterial activity by using peroxidase-like VOxC nanosheets (NSs) that prefer to chemically contact bacterial cell surface. The strategy combines the structure properties of VOxC NSs by coordinating with functional groups on bacteria cell wall with high affinity and the superior peroxidase-like activity of VOxC that can generate hydroxyl radicals for bacterial killing. The VOxC NSs are prepared by controlling the auto-oxidation of V2C NSs, possessing multivalent, ultrathin, flexible and entangled texture as well as good hydrophilicity and biocompatibility. VOxC NSs exhibit efficiently antibacterial activity toward E. coli and S. aureus. This study provides a promising strategy by using adhesive nanozymes in close proximity to the surface of targeted bacteria via chemical bonds, which will inspire the design and application of powerful antibacterial nanozymes with high efficiency.

Structural and biochemical insights into the bacteriophage PlyGRCS endolysin targeting methicillin-resistant Staphylococcus aureus (MRSA) and serendipitous discovery of its interaction with a cold shock protein C (CspC).

Methicillin-resistant Staphylococcus aureus (MRSA) causes life-threatening human infections. Bacteriophage-encoded endolysins degrade the cell walls of Gram-positive bacteria by selectively hydrolyzing the peptidoglycan layer and thus are promising candidates to combat bacterial infections. PlyGRCS, the S. aureus-specific bacteriophage endolysin, contains a catalytic CHAP domain and a cell-wall binding SH3_5 domain connected by a linker. Here, we show the crystal structure of full-length PlyGRCS refined to 2.1 Å resolution. In addition, a serendipitous finding revealed that PlyGRCS binds to cold-shock protein C (CspC) by interacting with its CHAP and SH3_5 domains. CspC is an RNA chaperone that plays regulatory roles by conferring bacterial adaptability to various stress conditions. PlyGRCS has substantial lytic activity against S. aureus and showed only minimal change in its lytic activity in the presence of CspC. Whereas the PlyGRCS-CspC complex greatly reduced CspC-nucleic acid binding, the aforesaid complex may downregulate the CspC function during bacterial infection. Overall, the crystal structure and biochemical results of PlyGRCS provide a molecular basis for the bacteriolytic activity of PlyGRCS against S. aureus.

Emergence of Nano-Based Formulations for Effective Delivery of Flavonoids against Topical Infectious Disorders.

Flavonoids are hydroxylated phenolic substances in vegetables, fruits, flowers, seeds, wine, tea, nuts, propolis, and honey. They belong to a versatile category of natural polyphenolic compounds. Their biological function depends on various factors such as their chemical structure, degree of hydroxylation, degree of polymerization conjugation, and substitutions. Flavonoids have gained considerable attention among researchers, as they show a wide range of pharmacological activities, including coronary heart disease prevention, antioxidative, hepatoprotective, anti-inflammatory, free-radical scavenging, anticancer, and anti-atherosclerotic activities. Plants synthesize flavonoid compounds in response to pathogen attacks, and these compounds exhibit potent antimicrobial (antibacterial, antifungal, and antiviral) activity against a wide range of pathogenic microorganisms. However, certain antibacterial flavonoids have the ability to selectively target the cell wall of bacteria and inhibit virulence factors, including biofilm formation. Moreover, some flavonoids are known to reverse antibiotic resistance and enhance the efficacy of existing antibiotic drugs. However, due to their poor solubility in water, flavonoids have limited oral bioavailability. They are quickly metabolized in the gastrointestinal region, which limits their ability to prevent and treat various disorders. The integration of flavonoids into nanomedicine constitutes a viable strategy for achieving efficient cutaneous delivery owing to their favorable encapsulation capacity and diminished toxicity. The utilization of nanoparticles or nanoformulations facilitates drug delivery by targeting the drug to the specific site of action and exhibits excellent physicochemical stability.

Dietary Flaxseed and Flaxseed Oil Differentially Modulate Aspects of the Microbiota Gut-Brain Axis Following an Acute Lipopolysaccharide Challenge in Male C57Bl/6 Mice.

The microbiota gut-brain axis (mGBA) is an important contributor to mental health and neurological and mood disorders. Lipopolysaccharides (LPS) are endotoxins that are components of Gram-negative bacteria cell walls and have been widely shown to induce both systemic and neuro-inflammation. Flaxseed (Linum usitatissimum) is an oilseed rich in fibre, n3-poly-unsaturated fatty acid (alpha-linolenic acid (ALA)), and lignan, secoisolariciresinol diglucoside, which all can induce beneficial effects across varying aspects of the mGBA. The objective of this study was to determine the potential for dietary supplementation with flaxseed or flaxseed oil to attenuate LPS-induced inflammation through modulation of the mGBA. In this study, 72 5-week-old male C57Bl/6 mice were fed one of three isocaloric diets for 3 weeks: (1) AIN-93G basal diet (BD), (2) BD + 10% flaxseed (FS), or (3) BD + 4% FS oil (FO). Mice were then injected with LPS (1 mg/kg i.p) or saline (n = 12/group) and samples were collected 24 h post-injection. Dietary supplementation with FS, but not FO, partially attenuated LPS-induced systemic (serum TNF-α and IL-10) and neuro-inflammation (hippocampal and/or medial prefrontal cortex IL-10, TNF-α, IL-1β mRNA expression), but had no effect on sickness and nest-building behaviours. FS-fed mice had enhanced fecal microbial diversity with increased relative abundance of beneficial microbial groups (i.e., Lachnospiraceae, Bifidobacterium, Coriobacteriaceae), reduced Akkermansia muciniphila, and increased production of short-chain fatty acids (SCFAs), which may play a role in its anti-inflammatory response. Overall, this study highlights the potential for flaxseed to attenuate LPS-induced inflammation, in part through modulation of the intestinal microbiota, an effect which may not be solely driven by its ALA-rich oil component.

Glutamine alleviates Lipopolysaccharide-induced corneal epithelial inflammation and oxidative stress in dogs

Pseudomonas aeruginosa is a common pathogenic bacteria in canine ophthalmology. Lipopolysaccharide (LPS), a component in the cell wall of gram-negative bacteria, is released following bacterial lysis and causes pathology and inflammation of the cornea. Antibiotics are used to treat bacterial keratitis, and the reuse of antibiotics can easily cause bacterial resistance. Research has shown that glutamine (GLN) has anti-inflammatory and antioxidant biological functions. Herein, we explored the effects and underlying mechanisms of GLN and established an LPS-induced cornea inflammation model. Treatment groups comprised: control check (CK), LPS, LPS + GLN, and Sham groups. Topical GLN treatment alleviated corneal opacity, reduced corneal injury, and accelerated corneal wound healing. Furthermore, GLN treatment altered the uniform distribution of corneal epithelial cells and transformed the healing approach of these cells in the corneal wound from crawling to filling. The expression of Toll-like receptor 4 (TLR4), IL-6, TNF-α, and p-p65 and the activity of myeloperoxidase and superoxide dismutase decreased while the content of malondialdehyde increased in the LPS + GLN group compared with those in the LPS group. Thus, our study suggests that LPS-induced inflammation and oxidative stress may be suppressed via the TLR4/NF-κB signaling pathway by GLN and that GLN could be used as an adjunct therapy to reduce antibiotic use.

Zinc-nanoparticles alleviate the ovarian damage induced by bacterial lipopolysaccharide (LPS) in pregnant rats and their fetuses

Lipopolysaccharide (LPS) is an endotoxin derived from the cell wall of Gram-negative bacteria. LPS exposure during early gestation is associated with adverse effects on the placenta as well as on developmental outcomes, including embryonic resorption, fetal death, congenital teratogenesis, and fetal growth retardation. This work aimed to explore the adverse effects of LPS injected at an early stage of gestation on the gonads of pregnant rats and the ovaries of their pups and the role of zinc nanoparticles (Zn-NPs) against these adverse effects. Twenty-four pregnant rats were used in this study. They were divided at gestation day 4 into four groups (n = 6): control, Zn-NPs (20 mg/kg orally from gestation day E14 till the end of weaning), LPS (50 µg/kg at gestation days E7 and E9), and LPS + Zn-NPs group. The body weight and placenta weight were recorded at gestational day 16. At postnatal day 21 (weaning), the mothers rats and their offspring were sacrificed and immediately dissected to remove the ovaries and uteri from the mothers and the ovaries from their offspring for subsequent biochemical, histological, and immunohistochemical investigations. The obtained results revealed that LPS exposure during early gestation caused severe histopathological alterations in the placenta, uterus, and ovaries of mothers, as well as in the ovaries of their pups. Also, the uterine and ovarian sections displayed a positive reaction for caspase-3 antibody and a negative reaction for Bcl-2 antibody, which reflects the apoptotic effect of LPS. Additionally, remarkable reductions in the levels of antioxidants (superoxide dismutase and catalase) and significant increases in malondialdehyde (MDA) levels were recorded in the serum of LPS-treated mothers and in the ovarian tissues of their offspring. Further biochemical analysis of the ovarian tissues from LPS-maternally treated offspring showed a significant increase in the levels of caspase-3, TNF-α, and TGF-β1, but a significant decrease in the level of IGF-1. On the other hand, treatment of mothers with Zn-NPs from day 14 of gestation until the weaning day (21st day postnatal) successfully ameliorated most of the deleterious histopathological, immunohistochemical, and biochemical changes induced by LPS.Graphical abstract

A microbiological identification and recovery actions of critical symptoms of anammox image bacteria

Currently, the risks posed by bacteria are becoming increasingly important. It now appears that the cell wall of Anammox image bacteria is very different from what has been generally considered for many years. Not every textbook contains the peptidoglycan on the cell wall of Anammox image bacteria - the sugar-protein chain that strengthens the cells of most bacteria. Most researchers in this Anammox image bacteria diseased identification wanted to find out what gave the Anammox image cell its stability. It used powerful cryo-electron microscopes to examine the bacterial cell wall and find the exact structure of the peptidoglycan. A new algorithm is proposed to discover that Anammox image bacteria contain peptidoglycan, which completes a theory in microbiology. The identification of different diseases is listed, and the proposed model compares the exact results while comparing the parameters like accuracy, precision, recall, and F1-Score. Keywords: Anammox image bacteria, cell wall, cell stability, cryo-electron, microscope images, accuracy, precision, recall, F1-score.