Ultraviolet Irradiation Treatment Research Articles

Orbea variegata (L.) Haw in skin carcinogenesis: insights from an in vivo male Swiss mouse model study

ABSTRACT Skin cancer is the most widespread type of malignant tumor representing a major public health concern. Considering the numerous side effects associated with conventional treatments, phytotherapy may be regarded as a viable medicinal alternative. This study aimed to investigate the therapeutic potential of Orbea variegata (L.) Haw, an ornamental plant, in treating skin cancer using an animal model induced by a combination of ultraviolet (UV) irradiation and sulfuric acid treatment. The hydroethanolic extract of Orbea variegata underwent phytochemical characterization, identifying the presence of reducing sugars, coumarins, alkaloids, flavonoids, tannins, and saponins through qualitative screening. Quantitative analysis demonstrated significant amounts of phenolic compounds (29.435 ± 0.571 mg GAE/g of dry extract), flavonoids (6.711 ± 0.272 mg QE/g of dry extract), and tannins (274.037 ± 11.3 mg CE/g of dry extract). The administration the hydroethanolic extract in two concentrations (1 or 2 g/kg) to male Swiss mice exhibited no marked adverse effects, as evidenced by serum aspartate aminotransferase (AST) and alanine aminotransferase (ALT) enzyme activity levels. In addition, the extract significantly reduced skin hyperplasia and inflammation induced by UV/sulfuric acid treatment as noted in tissue analyses and decreased protein expression of nuclear proliferation marker (Ki-67). This improvement was associated with a marked decrease in oxidative stress, as indicated by diminished lipid peroxidation levels, and restoration of the activity of endogenous antioxidant enzyme catalase (CAT) to control levels. Our findings demonstrated the potential of Orbea variegata hydroethanolic extract to be considered as a treatment for skin cancer, exhibiting its apparent safety and efficacy in reducing inflammation and carcinogenesis in a UV/sulfuric acid-induced Swiss mouse model, attributed to its phytochemical content and associated antioxidant activities.

Comparison of vacuum ultraviolet irradiation and oxygen plasma treatment as pretreatment for copper seed layer on cycloolefin polymer

This study explores the factors governing the peel strength characteristics between a cycloolefin polymer (COP) film and a copper plating layer with a copper seed layer, for applying to antenna circuits in 6 G communications. The peel strength depended on the surface modification methods as pretreatment for copper seed layer formation: vacuum ultraviolet (VUV) irradiation and oxygen plasma treatment. VUV irradiation induced a modified layer with brittleness on the COP surface, leading to substrate failure. Conversely, oxygen plasma treatment formed a quite thin modified layer and facilitated Cu2O formation by bonding functional groups on the topmost COP surface with copper in the seed layer at the interface between the COP film and the copper plating layer, resulting in interface failure rather than substrate failure. Therefore, enhancing peel strength involves preventing the formation of a modified layer on the surface and generating a significant quantity of functional groups on the topmost surface.

Microbiological Analysis of Manufacturing Processes and Microbial Hazard Assessment of Quality and Safety of Commercial Salted Shrimp (Saeu-jeot)

The objective of this study was to evaluate the microbiological properties of commercially available traditional Korean salted shrimp (Saeu-jeot) and to analyze the effects of saltwater immersion and ultraviolet (UV) irradiation on the reduction of Staphylococcus aureus in Saeu-jeot. A microbiological analysis was conducted across 56 commercially available Saeu-jeot samples from the Korean, Chinese, and Vietnamese markets. The microbiological analysis revealed no presence of Escherichia coli, coliforms, or Vibrio parahaemolyticus in any commercial samples. The total viable count and S. aureus were 3.8 ± 0.4 and 0.6 ± 0.3 log CFU/g, respectively. An investigation of the procedures conducted on Saeu-jeot samples at various production stages by Hazard Analysis Critical Control Point (HACCP)-certified companies demonstrated the substantial relevance of the raw material (tiny shrimp) on S. aureus counts. In order to reduce S. aureus in Saeu-jeot, saltwater immersion and UV irradiation treatments were applied, which reduced the S. aureus counts by 1.4 log CFU/g and 0.3 log CFU/g, respectively, and S. aureus’s efficacy was limited to the food’s surface. These results suggest that a co-treatment of saltwater immersion and UV irradiation could be effective in reducing S. aureus. The maintenance of hygienic handling and cleanliness are essential in the modern manufacturing processes of Saeu-jeot.

Single Fluorescent Probe for Multiple Tasks: Illuminating Lipid Droplets and Lysosomes in Dual Channels and Distinguishing Autophagy and Apoptosis.

Lipid droplets (LDs) and lysosomes play key roles in autophagy and cell apoptosis, and the discriminative visualization of the two organelles and simultaneously of autophagy and apoptosis is very helpful to understand their internal relationships. However, fluorescent probes that can concurrently achieve these tasks are not available currently. Herein, we delicately fabricate a robust probe CAQ2 for multiple tasks: illumination of LDs and lysosomes in dual emission colors as well as discriminative visualization of cell apoptosis and autophagy. The probe exhibited both lipophilic and basic properties and displayed different emission colors in neutral and protonated forms; thus, LDs and lysosomes emitted blue and red fluorescence colors, respectively. Because of the lysosomal acidification during autophagy, CAQ2 detected autophagy with evidently enhanced red emission. Because of the lysosomal alkalization during apoptosis, CAQ2 imaged apoptosis with a drastically decreased red fluorescence intensity. With the robust probe, the autophagy under starvation and lipidless conditions was visualized, and the apoptosis induced by H2O2, ultraviolet (UV) irradiation, and rotenone treatment was successfully observed. The efficient detoxification of Na2S against rotenone treatment was successfully revealed.

Disinfection of Bacteria in Aerosols by Applying High Voltage to Stranded Wire Electrodes.

The inactivation of airborne pathogenic microorganisms is crucial to attenuate the dissemination of infectious diseases induced by airborne pathogens. Conventional air disinfection methodologies, such as ultraviolet (UV) irradiation and ozone treatment, have demonstrated limited efficacy. Consequently, we investigated the potential of employing pulsed voltages to effectively eradicate bacteria within aerosols. Our inquiry revealed that the bacterial disinfection rate increased proportionally with elevated applied voltage and frequency. For instance, when a pulsed voltage of 20 kV and a frequency of 500 Hz were applied, a substantial disinfection rate exceeding 6.0 logarithmic units was attained. Furthermore, with the utilization of the stranded wire anodes, the disinfection intensity could be augmented by up to 2.0 logarithmic units compared with the solid wire configuration. Through the utilization of a stranded wire electrode model, we scrutinized the electric field encompassing the electrode, revealing a non-uniform electric field with the stranded wire electrode. This observation indicated an amplified bacterial disinfection effect, aligning with our experimental outcomes. These findings significantly enhance our comprehension of efficacious approaches to electrically disinfecting airborne bacteria.

Fabrication of high-aspect-ratio metallic microstructures by microelectroforming using silver-coated polydimethylsiloxane molds with controllable wettability

Abstract Microelectroforming is a specialized electroplating process to prepare functional metallic microstructures. However, the formability of microelectroforming is usually restricted by the limited mass transfer in high-aspect-ratio microcavities of molds. This paper presents a simple and reliable method utilizing silver (Ag)-coated polydimethylsiloxane (PDMS) molds with controllable wettability to enhance the formability of microelectroforming. The surfaces of these molds exhibited reversible water contact angles ranging from 4° to 151° realized through ultraviolet irradiation and heat treatment. The hydrophilicity of the PDMS molds facilitated liquid-phase mass transfer, contributing to the fabrication of complete and defect-free nickel microstructures with high aspect ratios. Subsequently, the hydrophobic PDMS molds reduced the interfacial adhesion between these molds and nickel microstructures, which was beneficial for perfect demolding. Nickel microstructures with an aspect ratio of 10 can be achieved by using the PDMS molds, which significantly enhance the formability of microelectroforming. This method provides a potential method to prepare high-aspect-ratio metallic microstructures.

Encapsulation of CsPb2Br5 in TiO2 Microcrystals to Enhance Environmental Stability.

All-inorganic lead halide perovskite has emerged as an attractive semiconducting material due to its unique optoelectronic properties. However, its poor environmental stability restricts its broad application. Here, a simple method for the fabrication of CsPb2Br5/TiO2 is investigated. The introduction of p-aminobenzoic acid, which has two functional groups, is critical for the capping of amorphous TiO2 on CsPb2Br5. After calcination at 300 °C, amorphous TiO2 crystallizes into the anatase phase. The CsPb2Br5/TiO2 NCs show high long-term stability in water and enhanced stability against ultraviolet radiation and heat treatment, owing to the chemical stability of TiO2. More importantly, photo-electrochemical characterizations indicate that the formation of TiO2 shells can increase the charge separation efficiency. Hence, CsPb2Br5/TiO2 exhibits improved photoelectric activity owing to the electrical conductivity of the TiO2 in water. This study provides a new route for the fabrication of optoelectronic devices and photocatalysts based on perovskite NCs in the aqueous phase. Furthermore, the present results demonstrate that CsPb2Br5/TiO2 NCs has considerable potential to be used as a photoelectric material in optical sensing and monitoring.

Emerging Drinking Water Borne Diseases: A Review on Types, Sources and Health Precaution

The global demand for safe drinking water become increasingly important in the past few years due to the growing world population, civilization and increase the sources of contaminations. Millions of peoples every year suffer from different waterborne disease, which may include microbial or disinfectant related diseases. This review, presents an overview on drinking water and their health impact from different aspects, going through different types of physical, chemical, and biological contaminants and their potential effect on human body upon the consumption of their contaminated water. The review also furtherly discusses drinking water treatment techniques such as chlorination, ultraviolet radiation treatment, chlorination, ozonation, heating, and ultra-filtration and the efficiency of these techniques to eliminate different water microorganisms. Drinking waterborne diseases of bacteria, viruses, parasitic protozoa and even some fungi have been also discussed. Finally, health precaution regarding drinking water in term of monitoring of different indicators as well as following the hygienic behaviors was covered to ensure the sustainability and safety of water consumption.

Animal Models for the Study of Keratoconus.

Keratoconus (KC) is characterized by localized, central thinning and cone-like protrusion of the cornea. Its precise etiology remains undetermined, although both genetic and environmental factors are known to contribute to disease susceptibility. Due to KC's complex nature, there is currently no ideal animal model to represent both the corneal phenotype and underlying pathophysiology. Attempts to establish a KC model have involved mice, rats, and rabbits, with some additional novel animals suggested. Genetic animal models have only been attempted in mice. Similarly, spontaneously occurring animal models for KC have only been discovered in mice. Models generated using chemical or environmental treatments have been attempted in mice, rats, and rabbits. Among several methods used to induce KC in animals, ultraviolet radiation exposure and treatment with collagenase are some of the most prevalent. There is a clear need for an experimental model animal to elucidate the underlying mechanisms behind the development and progression of keratoconus. An appropriate animal model could also aid in the development of treatments to slow or arrest the disorder.

Effects of UV radiation on photosynthesis of Sargassum muticum

As an invasive species of macroalgae, Sargassum muticum (Yendo) Fensholt has invaded European shores and the Mediterranean, and even drifting individuals have been observed in sea area near the Canary Islands, becoming a potential species responsible for the “Sargassum golden tide”. When drifting on the sea surface, algae receive more ultraviolet radiation (UVR). However, photosynthetic responses and adaptation mechanism of S. muticum to UVR remain unclear. In this study, thalli of S. muticum were respectively exposed under two radiation treatments of 200 W m−2 PAR (photosynthetically active radiation, 400–700 nm), and 200 W m−2 PAR + 38 W m−2 UVR (280–700 nm) for 120 mins, and then recovered at a low light (PAR) of 10 μmol photons m−2 s−1 for 240 mins. During this treatment, the photosynthetic properties of algae were measured, to investigate the responses and protection mechanism of S. muticum to UVR. The results showed that photosynthesis of thalli was significantly inhibited by UVR, reflected by decreased maximum photochemical quantum yield (Fv/Fm) and chlorophyll content, and changes of parameters of rapid light response curve and chlorophyll fluorescence induction curve in PAR and PAR + UVR treatments. Meanwhile, algae actively adopted several strategies to alleviate the inhibition caused by UVR, including photoprotection characterized by increased contents of UV-absorbing compounds (UVACs) and carotenoids (Car), excess light energy dissipation by elevated non-photochemical quenching (NPQ) coupled to the xanthophyll cycle, and photorepair manifested as an accelerated synthesis of D1 protein and enhanced antioxidant for scavenging ROS. Benefiting from the effects of the above several pathways, after 240 mins of low light recovery, photosynthesis was greatly restored in these two radiation treatments, with the restoration of Fv/Fm and parameters of rapid light response curve and chlorophyll fluorescence induction curve. Based on these results, we conservatively speculate that the photosynthesis of drifting S. muticum individuals may be restored in the evening with low light levels after being damaged by UVR on the surface of sea at midday, resulting in maintaining rapid growth and forming a golden tide.

Sunscreens can preserve human skin microbiome upon erythemal UV exposure.

Ultraviolet radiation (UVR) is a known environmental key factor for premature skin ageing. Only few scientific evidence is available to support the effects of UVR on the skin microbiome. This in vivo pilot study aimed to evaluate the impact on the skin microbiome upon erythemal UV exposure and the protection of UV-exposed skin microbiome by UV filters. Ten female volunteers were treated with an sun protection factor (SPF) 20 sunscreen and placebo formulation (without UV filters) on their upper middle backs and irradiated with an erythemal dose (2 MED) by a solar simulator. Skin swabbing samples from four zones (i.e., unexposed, exposed, sunscreen- and placebo-treated on exposed skin) were collected for the microbiome analysis before and 2 h after UV exposure, respectively, and processed via shallow 16S rRNA Amplicon and Shotgun metagenomic sequencing. An in vitro UV method was developed to confirm the protection of isolated bacterial strains by single UV filters and combinations. Alpha diversity was impacted by significant inter-individual differences and by treatment rather than by irradiation. Cutibacterium acnes was found to be the most abundant and a confounding factor for diversity. On a species level, Lactobacillus crispatus was negatively associated with UVR and placebo treatment, whereas there was a positive association with sunscreen treatment. The sunscreen treatment also favoured an interaction network with central Micrococcus genus. The in vitro results showed that both single UV filters and combinations had specific effects on the survival rates of L. crispatus, C. acnes, and Staphylococcus epidermidis. We identified potential microorganisms and bacterial interactions that were associated with an SPF 20 sunscreen treatment. The specific protection of L. crispatus as a key player in the UV-exposed skin microbiome and reduction of C. acnes population by UV filters might lead to new cosmetic concepts for photoprotection.

Using a Topical Formulation of Vitamin D for the Treatment of Vitiligo: A Systematic Review.

Vitamin D is one significant prohormone substance in human organ systems. It is a steroidal hormone produced in the skin upon exposure to UVB rays. This paper presents a systematic review of the utilization of topical vitamin D, specifically cholecalciferol, calcipotriol, and tacalcitol, in the treatment of vitiligo. It considers the role of vitamin D in stimulating the synthesis of melanin and melanogenesis, which can help with the process of repigmentation. The inclusion of calcipotriol or tacalcitol in Narrowband Ultraviolet Phototherapy (NB-UVB) has shown the potential to enhance therapeutic outcomes for vitiligo. However, their effectiveness in combination with Psoralens Long Wave Ultraviolet Radiation (PUVA) and Monochromatic Excimer Light (MEL) treatment for vitiligo is limited. In contrast, combining topical corticosteroids with vitamin D analogues has demonstrated superior efficacy in treating vitiligo compared to using vitamin D analogues alone, while also providing the added benefit of reducing corticosteroid-related adverse effects. In addition, treating stable vitiligo with topical cholecalciferol and microneedling has shown success. Future studies are needed to ascertain an efficient method of administering vitamin D topically as an anti-vitiligo agent.

Effect of ultraviolet irradiation treatment on shear bond strength between polymethyl methacrylate and cobalt-chromium-molybdenum alloy.

We aimed to elucidate the effects of ultraviolet (UV) irradiation on the shear bond strength (SBS) between heat-cured polymethyl methacrylate (PMMA) and a Co-Cr-Mo alloy. Disk-shaped Co-Cr-Mo alloy prepared by casting were subjected to different UV treatment times (0, 15, and 30 min). To determine the effect of UV treatment on surface properties of the alloy, surface roughness, wettability, and chemical compositions were analyzed. To evaluate the SBS, cylindrical PMMA was bonded to the UV-treated alloy, and subsequently subjected to the SBS test after 24 h of storage at room temperature or following 10,000 thermal cycles (n=10/group). After the UV treatment, the surface roughness remained unchanged, but oxidation resulted in the surface exhibiting greater hydrophilic characteristics. The UV-treated group showed significantly higher SBS values than those of the non-treated group (p<0.001). These results suggested that UV treatment-mediated oxidation improved the bond strength between PMMA and Co-Cr-Mo alloy.

Improving Simplicia of Kerangas Forest by Minimizing Microbial Content Under Ultraviolet Radiation Treatment

Kerangas forest is known as a source of traditional medicinal plants and thus potentially the source of simplicia. Medicinal plant preparations of simplicia are usually dried to meet water content standards (< 10%). However, in some cases the drying process carried out still does not eliminate the microbial content in the simplicia. This study aims to analyze the phytochemical compounds contained in three types of medicinal plant simplicia and the total microbial content by treatment with ultraviolet (UV) irradiation. The types of simplicia used were Baeckea frutescens leaves, Shorea balangeran bark and Vitex pubescens leaves (obtained from the kerangas forest). Before testing the total microbial content, simplicia first received UV irradiation. The first simplicia sample was not irradiated, while the next simplicia sample was given UV irradiation with a power of 60 watts and an irradiation time of 1, 2 and 4 h. The microbial content test used the total plate count method with the pour plate analysis technique. S. balangeran is unexposed species to microbes, even without UV irradiation. Radiation with a UV lamp for 1 h with a lamp power of 60 watts and a distance of the sample with a lamp of 30 cm effectively eliminates microbes in B. frutescens simplicia. Radiation for 4 h with a UV lamp of 60 watts and a sample distance of 30 cm was only able to eliminate the microbial content in V. pubescens simplicia. The results of this study indicate that S. balangeran has high potential to be developed as an antibacterial.

Characteristics in dissolved organic matter and disinfection by-product formation during advanced treatment processes of municipal secondary effluent with Orbitrap mass spectrometry

Dissolved organic matter (DOM) is reported to be a precursor to disinfection by-products (DBPs), which have adverse effects on human health. Therefore, it is crucial to effectively remove DOM before water disinfection. Characteristics of DOM and DBPs formation during advanced treatment processes including coagulation, adsorption, ultraviolet (UV) irradiation, and ozone (O3) oxidation in municipal secondary effluent were investigated in this research. DOM was characterized by Fourier transform infrared spectroscopy (FTIR), excitation-emission matrix fluorescence spectroscopy (EEM), and Orbitrap mass spectrometry (Orbitrap MS). Moreover, DBPs formation potential under different advanced treatment processes was also discussed. FTIR results indicated that various functional groups existing in DOM may react with the disinfectant to form toxic DBPs. EEM analysis indicated that DOM in all water samples was dominated by soluble microbial product-like (SMPs) and humic acid-like (HA) substances. The municipal secondary effluent was abundant with DOM and rich in carbon, hydrogen, oxygen, and nitrogen atoms, contained a certain dosage of phosphorus and sulfur atoms, and the highest proportion is lignin. Most of the precursors (CHO features) had positive double bond equivalent subtracted oxygen per carbon [(DBE-O)/C] and negative carbon oxidation state (Cos) in all four different advanced treatment processes. DBPs formation potential (DBPFP) of coagulation, adsorption, UV irradiation, and O3 oxidation advanced treatment processes were 487 μg L−1, 586 μg L−1, 597 μg L−1, and 308 μg L−1, respectively. And the DBPs precursors removal efficiency of coagulation, adsorption, UV irradiation, and O3 oxidation advanced treatment processes were 50.8%, 40.8%, 39.8%, and 69.0%, respectively. This study provides in-depth insights into the changes of DOM in municipal secondary effluent at the molecular level and the removal efficiency of DBPs precursors during coagulation, adsorption, UV irradiation, and O3 oxidation advanced treatment processes.

Mutagenicity assessment of high-power 1.6-THz pulse laser radiation.

The effect of terahertz (THz) radiation has been studied in medicine. However, there is a lack of scientific information regarding its possible mutagenicity. Therefore, the present study aimed to assess the mutagenicity of 1.6 THz laser irradiation. The Ames test was conducted using five bacterial tester strains. The bacteria were subjected to (i) 1.6 THz laser irradiation at 3.8 mW/cm2 for 60 min using a tabletop THz pulse laser system, (ii) ultraviolet irradiation, (iii) treatment with positive control chemicals (positive control) or (iv) treatment with the solvent used in the positive control (negative control). After treatment, the bacterial suspensions were cultured on minimal glucose agar to determine the number of revertant colonies. In addition, the comet assay was performed using fibroblasts (V79) to assess possible DNA damage caused by the THz laser irradiation. The Ames test demonstrated that the THz laser irradiation did not increase the number of revertant colonies compared to that in the negative control group, whereas the ultraviolet irradiation and positive control treatment increased the number of revertant colonies. Thus, 1.6 THz laser irradiation is unlikely to be mutagenic. The comet assay additionally suggests that the THz laser irradiation unlikely induce cellular DNA damage.

Strain-Driven Negative Resistance Switching of Conductive Fibers with Adjustable Sensitivity for Wearable Healthcare Monitoring Systems with Near-Zero Standby Power.

Recently, one of the primary concerns in e-textile-based healthcare monitoring systems for chronic illness patients has been reducing wasted power consumption, as the system should be always-on to capture diverse biochemical and physiological characteristics. However, the general conductive fibers, a major component of the existing wearable monitoring systems, have a positive gauge-factor (GF) that increases electrical resistance when stretched, so that the systems have no choice but to consume power continuously. Herein, a twisted conductive-fiber-based negatively responsive switch-type (NRS) strain-sensor with an extremely high negative GF (resistance change ratio ≈ 3.9× 108 ) that can significantly increase its conductivity from insulating to conducting properties is developed. To this end, a precision cracking technology is devised, which could induce a difference in the Young's modulus of the encapsulated layer on the fiber through selective ultraviolet-irradiation treatment. Owing to this technology, the NRS strain-sensors can allow for effective regulation of the mutual contact resistance under tensile strain while maintaining superior durability for over 5000 stretching cycles. For further practical demonstrations, three healthcare monitoring systems (E-fitness pants, smart-masks, and posture correction T-shirts) with near-zero standby power are also developed, which opens up advancements in electronic textiles by expanding the utilization range of fiber strain-sensors.

MiR-1273h-5p protects the human corneal epithelium against UVR-induced oxidative stress and apoptosis: Role of miR-1273h-5p in climatic droplet keratopathy

Climatic droplet keratopathy (CDK) is characterized by an increased number of oil-like deposits on the most anterior corneal layers, which affect vision and can cause blindness. Environmental ultraviolet radiation (UVR) exposure is a major risk factor, but the underlying mechanism of CDK pathogenesis is unclear. Increasing evidence has demonstrated that miRNAs participate in the cross-talk with oxidative stress. We aimed to explore whether certain miRNAs are involved in the pathogenesis of CDK. We performed miRNA sequencing of tears from patients with CDK and healthy individuals from Tacheng region of Xinjiang and conducted bioinformatic analysis of key miRNAs. We also evaluated viability, migration, and apoptosis of human corneal epithelial cells (HCECs) subjected to UVR treatment. miR-1273h-5p expression was abnormally downregulated in the tears of patients with CDK. miR-1273h-5p promoted cell proliferation and migration and inhibited UVR-induced mitochondrial apoptosis. miR-1273h-5p protected HCECs against UVR-induced oxidative damage by reducing the accumulation of reactive oxygen species and inhibiting mitochondrial apoptosis via the activation of the Nrf2 pathway. Thus, our results suggest that miR-1273h-5p protects the corneal epithelium against UVR-induced oxidative stress damage.

DEVELOPMENT OF ENTEROBACTER CLOACAE IP8 MUTANT STRAIN PRODUCING THERMOSTABLE CELLULASE

Mutagenesis of Enterobacter cloacae IP8 for enhanced cellulase production was carried out using ultraviolet (UV) irradiation and ethyl methanesulphonate (EMS) treatment. The mutant strain exhibited cellulolytic activity which was 2.18-fold higher than that of the wildtype strain. The optimal conditions for cellulase production were an incubation period of 28 h, a temperature of 45 oC, and pH 7.0, using CMC and peptone as carbon and nitrogen sources, respectively. The cellulases from both strains were purified by using ammonium sulfate precipitation, CM Sephadex C-50, and Biogel P-100 column chromatography. The specific activity of the purified cellulase from the mutant strain was 29.47 U/mg while that of wildtype cellulase was 21.5 U/mg. Biochemical characterization of the purified enzyme revealed the optimum pH and temperature of 8.0 and 65 oC, respectively, for the cellulase from the mutant strain, and 7.0 and 60 oC for the wild-type cellulase. The mutant cellulase was thermally stable up to 70 oC retaining 86.5% of its original activity after 180 h. Metal ions Na+ and Ca2+ remarkably enhanced the activity of the cellulase from both strains while Al3+ and the chelating agent, EDTA, strongly inhibited the activity. Mutagenesis of E. cloacae IP8 using combined UV and EMS treatment led to the development of mutant strain with enhanced capacity for the production of cellulase exhibiting novel properties such as thermostability, alkalinity, low Km, and high Vmax values. Therefore, the enzyme from the mutant strain of E. cloacae IP8 has the potential for broad industrial applications.

Interactive Effects of Ultraviolet Irradiation and Biochar Treatment on the Growth and Active Ingredients of Pseudostellaria heterophylla

Interactive Effects of Ultraviolet Irradiation and Biochar Treatment on the Growth and Active Ingredients of Pseudostellaria heterophylla