Autophagy Activation Promoted by Pulses of Light and Phytochemicals Counteracting Oxidative Stress during Age-Related Macular Degeneration.

The seminal role of autophagy during age-related macular degeneration (AMD) lies in the clearance of a number of reactive oxidative species that generate dysfunctional mitochondria. In fact, reactive oxygen species (ROS) in the retina generate misfolded proteins, alter lipids and sugars composition, disrupt DNA integrity, damage cell organelles and produce retinal inclusions while causing AMD. This explains why autophagy in the retinal pigment epithelium (RPE), mostly at the macular level, is essential in AMD and even in baseline conditions to provide a powerful and fast replacement of oxidized molecules and ROS-damaged mitochondria.

The Essential Role of Light-Induced Autophagy in the Inner Choroid/Outer Retinal Neurovascular Unit in Baseline Conditions and Degeneration.

The present article discusses the role of light in altering autophagy, both within the outer retina (retinal pigment epithelium, RPE, and the outer segment of photoreceptors) and the inner choroid (Bruch's membrane, BM, endothelial cells and the pericytes of choriocapillaris, CC). Here autophagy is needed to maintain the high metabolic requirements and to provide the specific physiological activity sub-serving the process of vision. Activation or inhibition of autophagy within RPE strongly depends on light exposure and it is concomitant with activation or inhibition of the outer segment of the photoreceptors.

Pulsed blue light, saliva and curcumin significantly inactivate human coronavirus.

In a recent study, we showed that pulsed blue light (PBL) inactivates as much as 52.3% of human beta coronavirus HCoV-OC43, a surrogate of SARS-CoV-2, and one of the major strains of viruses responsible for the annual epidemic of the common cold. Since curcumin and saliva are similarly antiviral and curcumin acts as blue light photosensitizer, we used Qubit fluorometry and WarmStart RT-LAMP assays to study the effect of combining 405 nm, 410 nm, 425 nm or 450 nm wavelengths of PBL with curcumin, saliva or a combination of curcumin and saliva against human beta coronavirus HCoV-OC43.

Pulsed blue light inactivates two strains of human coronavirus.

Emerging evidence suggests that blue light has the potential to inactivate viruses. Therefore, we investigated the effect of 405 nm, 410 nm, 425 nm and 450 nm pulsed blue light (PBL) on human alpha coronavirus HCoV-229 E and human beta coronavirus HCoV-OC43, using Qubit fluorometry and RT-LAMP to quantitate the amount of nucleic acid in irradiated and control samples. Like SARS-CoV-2, HCoV-229E and HCoV-OC43 are single stranded RNA viruses transmitted by air and direct contact; they have similar genomic sizes as SARS-CoV-2, and are used as surrogates for SARS-CoV-2.

Blue light absorbing pigment in Streptococcus agalactiae does not potentiate the antimicrobial effect of pulsed 450 nm light.

Introduction: Recently, it was shown that Group B Streptococcus (GBS) COH1 strain, which has granadaene-an endogenous chromophore known to absorb blue light-is not susceptible to 450 nm pulsed blue light (PBL) inactivation unless the bacterium is co-cultured with exogenous porphyrin.

Purpose: To confirm or refute the finding, we studied the effect of blue light on NCTC, another strain of GBS with more granadaene than COH1, to determine if the abundance of granadaene-and by implication more absorption of blue light-fosters GBS susceptibility to PBL.

Methods: We irradiated cultures of the bacterium with or without protoporphyrin, coproporphyrin, flavin mononucleotide (FMN), flavin adenine dinucleotide (FAD), nicotinamide adenine dinucleotide (NAD) or NADH.

Structural membrane changes induced by pulsed blue light on methicillin-resistant Staphylococcus aureus (MRSA).

Background: In a recent study we showed that blue light inactivates methicillin-resistant Staphylococcus aureus (MRSA) by perturbing, depolarizing, and disrupting its cell membrane.

Purpose: The current study presents visual evidence that the observed biochemical changes also result in cell metabolic changes and structural alteration of the cell membrane.

Methods: Cultures of MRSA were treated with 450 nm pulsed blue light (PBL) at 3 mW/cm irradiance, using a sub lethal dose of 2.

The viability of human cells irradiated with 470-nm light at various radiant energies in vitro.

Blue light is known to be antimicrobial, but its effect on normal cutaneous and subcutaneous cells remains unclear. Therefore, we studied the effect of 470-nm light on the viability of adult and neonatal human dermal fibroblasts, Jurkat T-cells, and THP-1 monocytes in vitro. Each culture was irradiated with 0, 3, 55, or 110 J/cm of 470-nm light and subjected to trypan blue assay to ascertain viability.

The importance of porphyrins in blue light suppression of Streptococcus agalactiae.

It is well documented that blue light absorption by bacterial chromophores triggers downstream production of reactive oxygen species (ROS), which in turn results in bacterial cell death. To elucidate the importance of chromophores in the bactericidal effect of blue light, and to determine whether blue light absorption per se or the presence of porphyrins known to engender ROS is crucial in blue light treatment, we studied the effect of 450 nm pulsed light on Streptococcus agalactiae, also known as Group B Streptococcus (GBS) strain COH1. GBS does not synthesize porphyrins but has a blue light-absorbing chromophore, granadaene.

Light as a potential treatment for pandemic coronavirus infections: A perspective.

The recent outbreak of COVID-19, which continues to ravage communities with high death tolls and untold psychosocial and catastrophic economic consequences, is a vivid reminder of nature's capacity to defy contemporary healthcare. The pandemic calls for rapid mobilization of every potential clinical tool, including phototherapy-one of the most effective treatments used to reduce the impact of the 1918 "Spanish influenza" pandemic. This paper cites several studies showing that phototherapy has immense potential to reduce the impact of coronavirus diseases, and offers suggested ways that the healthcare industry can integrate modern light technologies in the fight against COVID-19 and other infections.

Pulsed 450 nm blue light significantly inactivates Propionibacterium acnes more than continuous wave blue light.

Infection with Propionibacterium acnes is ubiquitous, and drug resistant strains have been on the rise as the use of pharmaceutical antimicrobials continues to engender the emergence of further resistant strains. In previous studies, we showed that treatment with blue light serves as an alternative to pharmaceutical intervention. As a part of our ongoing effort to improve the antimicrobial efficacy of blue light, we studied the effect of pulsed 450 nm light on P.

Pulsed 450 nm blue light suppresses MRSA and Propionibacterium acnes in planktonic cultures and bacterial biofilms.

In our recent study, we showed that pulsed blue light (PBL) suppresses the growth of Propionibacterium acnes more than continuous wave (CW) blue light in vitro, but it is not known that other bacteria, such as methicillin-resistant Staphylococcus aureus (MRSA), respond similarly to PBL. The high potency of PBL relative to CW blue light makes it a suitable antimicrobial for suppressing bacterial growth in biofilms as well. Therefore, we determined if MRSA-a deadly bacterium of global concern-is susceptible to 450 nm PBL irradiation in vitro, and ascertained whether the bactericidal effect of PBL on planktonic P.

Optimizing the bactericidal effect of pulsed blue light on Propionibacterium acnes - A correlative fluorescence spectroscopy study.

Propionibacterium acnes infection is the eighth most prevalent disease, affecting 80% of people worldwide. Resistance to antibiotics has been on the rise; over 40% of acne infections now resist commonly used topical and oral anti-acnes antibiotics, making treatment difficult. In our effort to refine blue light as an alternative safe clinically effective treatment, we determined if 100% bacterial suppression is attainable at ultralow irradiances and radiant energies, and explored the relationship between bacterial suppression and fluorescence during treatment.

Rare mutations in Pfmdr1 gene of Plasmodium falciparum detected in clinical isolates from patients treated with anti-malarial drug in Nigeria.

Background: Plasmodium falciparum, the deadliest causative agent of malaria, has high prevalence in Nigeria. Drug resistance causing failure of previously effective drugs has compromised anti-malarial treatment. On this basis, there is need for a proactive surveillance for resistance markers to the currently recommended artemisinin-based combination therapy (ACT), for early detection of resistance before it become widespread.

Understanding the antimicrobial activity of selected disinfectants against methicillin-resistant Staphylococcus aureus (MRSA).

Disinfectants and biocidal products have been widely used to combat Methicillin-resistant Staphylococcus aureus (MRSA) infections in homes and healthcare environments. Although disruption of cytoplasmic membrane integrity has been documented as the main bactericidal effect of biocides, little is known about the biochemical alterations induced by these chemical agents. In this study, we used Fourier transform infrared (FT-IR) spectroscopy and chemometric tools as an alternative non-destructive technique to determine the bactericidal effects of commonly used disinfectants against MRSA USA-300.

Blue/violet laser inactivates methicillin-resistant Staphylococcus aureus by altering its transmembrane potential.

The resistance of methicillin-resistant Staphylococcus aureus to antibiotics presents serious clinical problems that prompted the need for finding alternative or combination therapies. One such therapy is irradiation with blue light. To determine the alterations in metabolic processes implicated in the observed antimicrobial effects of blue light, we investigated the changes in membrane potential and the presence of free-radical-producing photo-acceptor molecules.

Spectrally resolved infrared microscopy and chemometric tools to reveal the interaction between blue light (470nm) and methicillin-resistant Staphylococcus aureus.

Blue light inactivates methicillin-resistant Staphylococcus aureus (MRSA), a Gram-positive antibiotic resistant bacterium that leads to fatal infections; however, the mechanism of bacterial death remains unclear. In this paper, to uncover the mechanism underlying the bactericidal effect of blue light, a combination of Fourier transform infrared (FTIR) spectroscopy and chemometric tools is employed to detect the photoreactivity of MRSA and its distinctive pathway toward apoptosis after treatment. The mechanism of action of UV light and vancomycin against MRSA is also investigated to support the findings.

Blue light does not impair wound healing in vitro.

Irradiation with red or near infrared light promotes tissue repair, while treatment with blue light is known to be antimicrobial. Consequently, it is thought that infected wounds could benefit more from combined blue and red/infrared light therapy; but there is a concern that blue light may slow healing. We investigated the effect of blue 470nm light on wound healing, in terms of wound closure, total protein and collagen synthesis, growth factor and cytokines expression, in an in vitro scratch wound model.

A comparison of four methods for determining viability in human dermal fibroblasts irradiated with blue light.

Introduction: Several tests are available for assessing the viability of cells; however, there is a dearth of studies comparing the results obtained with each test. We compared the capability of four viability assays (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromide (MTT), neutral red, trypan blue and live/dead fluorescence), to detect potential toxicity in fibroblasts irradiated with 470nm blue light.

Methods: Cells were irradiated at 3, 55, 110 and 220J/cm(2), incubated for 24h and viability assessed using each test.

The relative antimicrobial effect of blue 405 nm LED and blue 405 nm laser on methicillin-resistant Staphylococcus aureus in vitro.

It has long been argued that light from a laser diode is superior to light from a light-emitting diode (LED) in terms of its effect on biological tissues. In order to shed light on this ongoing debate, we compared the antimicrobial effect of light emitted from a 405-nm LED with that of a 405-nm laser on methicillin-resistant Staphylococcus aureus (MRSA) at comparable fluences. We cultured 5 × 10(6) CFU/ml MRSA on tryptic soy agar and then irradiated culture plates once, twice, or thrice with either LED or laser light using 40, 54, 81, or 121 J/cm(2) fluence at 15-, 30-, or 240-min time interval between irradiation.

Blue 470 nm light suppresses the growth of Salmonella enterica and methicillin-resistant Staphylococcus aureus (MRSA) in vitro.

Background And Objective: Emerging evidence suggests that blue light can photo-inactivate some bacteria of clinical importance. Consequently, we tested the hypothesis that 470 nm light can suppress growth of two recalcitrant bacteria, MRSA and Salmonella.

Materials And Methods: We plated 5 × 10 and 7 × 10 CFU/ml USA300 strain of MRSA and 1 × 10 CFU/ml of Salmonella enterica serovars Typhimurium and Heidelberg.

Whole-Genome Sequence for Methicillin-Resistant Staphylococcus aureus Strain ATCC BAA-1680.

We report here the whole-genome sequence of the USA300 strain of methicillin-resistant Staphylococcus aureus (MRSA), designated ATCC BAA-1680, and commonly referred to as community-associated MRSA (CA-MRSA). This clinical MRSA isolate is commercially available from the American Type Culture Collection (ATCC) and is widely utilized as a control strain for research applications and clinical diagnosis. The isolate was propagated in ATCC medium 18, tryptic soy agar, and has been utilized as a model S.

The bactericidal effect of 470-nm light and hyperbaric oxygen on methicillin-resistant Staphylococcus aureus (MRSA).

It has been shown that, in vitro, hyperbaric oxygen (HBO) suppresses 28 % bacterial growth, while 470-nm blue light alone suppresses up to 92 % methicillin-resistant Staphylococcus aureus (MRSA) in one application in vitro. Therefore, we determined if combined 470-nm light (55 J/cm(2)) and HBO will yield 100 % bacterial suppression in experimental simulation of mild, moderate or severe MRSA infection. We cultured MRSA at 3 × 10(6), 5 × 10(6), 7 × 10(6), 8 × 10(6), or 12 × 10(6) CFU/ml and treated each concentration in four groups as follows: (1) control (no treatment) (2) photo-irradiation only, (3) photo-irradiation then HBO, (4) HBO only, and (5) HBO then photo-irradiation.

Optimization of the antimicrobial effect of blue light on methicillin-resistant Staphylococcus aureus (MRSA) in vitro.

Background And Objective: In previous studies, we showed that irradiation with 405 nm or 470 nm light suppresses up to 92% methicillin-resistant Staphylococcus aureus (MRSA) growth in vitro and that the remaining bacteria re-colonize. In this study, the aim was to develop a protocol that yields 100% MRSA growth suppression.

Materials And Methods: We cultured 3 × 10(6) and 5 × 10(6) CFU/ml USA300 strain of MRSA and then irradiated each plate with varying fluences of 1-60 J/cm2 of 405 nm or 470 nm light, either once or twice at 6 hours intervals.

Molecular typing reveals substantial Plasmodium vivax infection in asymptomatic adults in a rural area of Cameroon.

Background: Malaria in Cameroon is due to infections by Plasmodium falciparum and, to a lesser extent, Plasmodium malariae and Plasmodium ovale, but rarely Plasmodium vivax. A recent report suggested "Plasmodium vivax-like" infections around the study area that remained unconfirmed. Therefore, molecular and antigenic typing was used to investigate the prevalence of P.