Hierarchical Self-Assembly Molecular Building Blocks as Intelligent Nanoplatforms for Ovarian Cancer Theranostics.

Hierarchical self-assembly from simple building blocks to complex polymers is a feasible approach to constructing multi-functional smart materials. However, the polymerization process of polymers often involves challenges such as the design of building blocks and the drive of external energy. Here, a hierarchical self-assembly with self-driven and energy conversion capabilities based on p-aminophenol and diethylenetriamine building blocks is reported. Through ß-galactosidase (ß-Gal) specific activation to the self-assembly, the intelligent assemblies (oligomer and superpolymer) with excellent photothermal and fluorescent properties are dynamically formed in situ, and thus the sensitive multi-mode detection of ß-Gal activity is realized. Based on the overexpression of ß-Gal in ovarian cancer cells, the self-assembly superpolymer is specifically generated in SKOV-3 cells to achieve fluorescence imaging. The photothermal therapeutic ability of the self-assembly oligomer (synthesized in vitro) is evaluated by a subcutaneous ovarian cancer model, showing satisfactory anti-tumor effects. This work expands the construction of intelligent assemblies through the self-driven cascade assembly of small molecules and provides new methods for the diagnosis and treatment of ovarian cancer.

A novel mouse model carrying a gene trap insertion into the Hmgxb4 gene locus to examine Hmgxb4 expression in vivo.

HMG (high mobility group) proteins are a diverse family of nonhistone chromosomal proteins that interact with DNA and a wide range of transcriptional regulators to regulate the structural architecture of DNA. HMGXB4 (also known as HMG2L1) is an HMG protein family member that contains a single HMG box domain. Our previous studies have demonstrated that HMGXB4 suppresses smooth muscle differentiation and exacerbates endotoxemia by promoting a systemic inflammatory response in mice. However, the expression of Hmgxb4 in vivo has not fully examined. Herein, we generated a mouse model that harbors a gene trap in the form of a lacZ gene insertion into the Hmgxb4 gene. This mouse enables the visualization of endogenous HMGXB4 expression in different tissues via staining for the ß-galactosidase activity of LacZ which is under the control of the endogenous Hmgxb4 gene promoter. We found that HMGXB4 is widely expressed in mouse tissues and is a nuclear protein. Furthermore, the Hmgxb4 gene trap mice exhibit normal cardiac function and blood pressure. Measurement of ß-galactosidase activity in the Hmgxb4 gene trap mice demonstrated that the arterial injury significantly induces Hmgxb4 expression. In summary, the Hmgxb4 gene trap reporter mouse described here provides a valuable tool to examine the expression level of endogenous Hmgxb4 in both physiological and pathological settings in vivo.

Comparative genome analysis of three classical E. coli cloning strains designed for blue/white selection: JM83, JM109 and XL1-Blue.

The development of the Escherichia coli K-12 laboratory strains JM83, JM109 and XL1-Blue was instrumental in early gene technology. We report the comprehensive genome sequence analysis of JM83 and XL1-Blue using Illumina and Oxford Nanopore technologies and a comparison with both the wild-type sequence (MG1655) and the genome of JM109 deposited at GenBank. Our investigation provides insight into the way how the genomic background that allows blue/white colony selection-by complementing a functionally inactive ω-fragment of ß-galactosidase (LacZ) with its α-peptide encoded on the cloning vector-has been implemented independently in these three strains using classical bacterial genetics. In fact, their comparative analysis reveals recurrent motifs: (i) inactivation of the native enzyme via large deletions of chromosomal regions encompassing the lac locus, or a chemically induced frameshift deletion at the beginning of the lacZ cistron, and (ii) utilization of a defective prophage (ϕ80), or an F'-plasmid, to provide the lacZ∆M15 allele encoding its ω-fragment. While the genetic manipulations of the E. coli strains involved repeated use of mobile genetic elements as well as harsh chemical or physical mutagenesis, the individual modified traits appear remarkably stable as they can be found even in distantly related laboratory strains, beyond those investigated here. Our detailed characterization at the genome sequence level not only offers clues about the mechanisms of classical gene transduction and transposition but should also guide the future fine-tuning of E. coli strains for gene cloning and protein expression, including phage display techniques, utilizing advanced tools for site-specific genome engineering.

ß-Galactosidase-Triggered Photodynamic Elimination of Senescent Cells with a Boron Dipyrromethene-Based Photosensitizer.

Senescence is a cellular response having physiological and reparative functions to preserve tissue homeostasis and suppress tumor growth. However, the accumulation of senescent cells would cause deleterious effects that lead to age-related dysfunctions and cancer progression. Hence, selective detection and elimination of senescent cells are crucial yet remain a challenge. A ß-galactosidase (ß-gal)-activated boron dipyrromethene (BODIPY)-based photosensitizer (compound 1) is reported here that can selectively detect and eradicate senescent cells. It contains a galactose moiety connected to a pyridinium BODIPY via a self-immolative nitrophenylene linker, of which the photoactivity is effectively quenched. Upon interactions with the senescence-associated ß-gal, it undergoes enzymatic hydrolysis followed by self-immolation, leading to the release of an activated BODIPY moiety by which the fluorescence emission and singlet oxygen generation are restored. The ability of 1 to detect and eliminate senescent cells is demonstrated in vitro and in vivo, using SK-Mel-103 tumor-bearing mice treated with senescence-inducing therapy. The results demonstrate that 1 can be selectively activated in senescent cells to trigger a robust senolytic effect upon irradiation. This study breaks new ground in the design and application of new senolytic agents based on photodynamic therapy.

The archaeal highly thermostable GH35 family ß-galactosidase DaßGal has a unique seven domain protein fold.

The most extensively studied ß-d-galactosidases (EC3.2.1.23) belonging to four glycoside hydrolase (GH) families 1, 2, 35, and 42 are widely distributed among Bacteria, Archaea and Eukaryotes. Here, we report a novel GH35 family ß-galactosidase from the hyperthermophilic Thermoprotei archaeon Desulfurococcus amylolyticus (DaßGal). Unlike fungal monomeric six-domain ß-galactosidases, the DaßGal enzyme is a dimer; it has an extra jelly roll domain D7 and three composite domains (D4, D5, and D6) that are formed by the distantly located polypeptide chain regions. The enzyme possesses a high specificity for ß-d-galactopyranosides, and its distinguishing feature is the ability to cleave pNP-ß-d-fucopyranoside. DaßGal efficiently catalyzes the hydrolysis of lactose at high temperatures, remains stable and active at 65 °Ð¡, and retains activity at 95 °Ð¡ with a half-life time value equal to 73 min. These properties make archaeal DaßGal a more attractive candidate for biotechnology than the widely used fungal ß-galactosidases.

Safety evaluation of the food enzyme ß-galactosidase from the non-genetically modified Papiliotrema terrestris strain AE-BLC.

The food enzyme ß-galactosidase (ß-d-galactoside galactohydrolase; EC 3.2.1.23) is produced with the non-genetically modified Papiliotrema terrestris strain AE-BLC by Amano Enzyme Inc. The food enzyme was considered free from viable cells of the production organism. It is intended to be used in the production of galacto-oligosaccharides (GOS) from lactose. Dietary exposure to the food enzyme-total organic solids (TOS) was estimated to be up to 0.441 mg TOS/kg body weight (bw) per day in European populations. Genotoxicity tests did not indicate a safety concern. The systemic toxicity was assessed by means of a repeated dose 90-day oral toxicity study in rats. The Panel identified a no observed adverse effect level of 1800 mg TOS/kg bw per day, the highest dose tested, which, when compared with the estimated dietary exposure, resulted in a margin of exposure of at least 4082. A search for the similarity of the amino acid sequence of the food enzyme to known allergens was made and no match was found. The Panel considered that a risk of allergic reactions upon dietary exposure to this food enzyme cannot be excluded, but the likelihood is low. Based on the data provided, the Panel concluded that this food enzyme does not give rise to safety concerns under the intended conditions of use.

Senolytic Therapy Enabled by Senescent Cell-Sensitive Biomimetic Melanin Nano-Senolytics.

Cellular senescence is a significant risk factor for aging and age-related diseases (ARD). The canonical senolytics Dasatinib and Quercetin (DQ) have shown promise in clearing senescent cells (SnCs); however, the lack of selectivity poses a challenge in achieving optimal outcomes. Despite the recent occurrence of nanomaterial-based approaches targeting SnCs, limited therapeutic effects, and potential toxicity still remain a major concern. Herein, a "double locks-like" nanoplatform is developed that integrated Galactan coating and mesoporous polydopamine to encase the senolytic drug DQ. By this way, DQ is only released in SnCs that are featured with higher levels of ß-galactosidase (ß-gal) and low PH. Additionally, the nanoparticles are equipped with 2,2,6,6-Tetramethylpiperidine-1-oxyl (Tempo) to gain enhanced photothermal converting potential. Consequently, the synthesized nanosenolytics demonstrate remarkable specificity and efficacy in eradicating SnCs, and accordingly reverse pulmonary fibrosis in mice without affecting normal tissues. Upon exposure of near-infrared (NIR) light, the nanoparticles demonstrate to efficiently remove senescent tumor cells inducted by chemotherapy, thereby hindering the outgrowth and metastasis or breast cancer. Collectively, the present study develops an "On/Off" switchable nanoplatform in response to SnCs, and produces a more safe, efficient, and feasible way to delay aging or alleviate age-associated diseases.

Evaluation of hydrolyzed cheese whey medium for enhanced bacterial cellulose production by Komagataeibacter rhaeticus MSCL 1463.

Industrial production of bacterial cellulose (BC) remains challenging due to significant production costs, including the choice of appropriate growth media. This research focuses on optimization of cheese whey (CW) based media for enhanced production of BC. Two modifications were made for CW medium for BC production with Komagataeibacter rhaeticus MSCL 1463. BC production in a medium of enzymatically hydrolyzed CW (final concentration of monosaccharides: glucose 0.13 g L-1, galactose 1.24 g L-1) was significantly enhanced, achieving a yield of 4.95 ± 0.25 g L-1, which markedly surpasses the yields obtained with the standard Hestrin-Schramm (HS) medium containing 20 g L-1 glucose and acid-hydrolyzed CW (final concentration of monosaccharides: glucose 1.15 g L-1, galactose 2.01 g L-1), which yielded 3.29 ± 0.12 g L-1 and 1.01 ± 0.14 g L-1, respectively. We explored the synergistic effects of combining CW with various agricultural by-products (corn steep liquor (CSL), apple juice, and sugar beet molasses). Notably, the supplementation with 15% corn steep liquor significantly enhanced BC productivity, achieving 6.97 ± 0.17 g L-1. A comprehensive analysis of the BC's physical and mechanical properties indicated significant alterations in fiber diameter (62-167 nm), crystallinity index (71.1-85.9%), and specific strength (35-82 MPa × cm3 g-1), as well as changes in the density (1.1-1.4 g cm-3). Hydrolyzed CW medium supplemented by CSL could be used for effective production of BC.

Safety evaluation of the food enzyme ß-galactosidase from the genetically modified Bacillus licheniformis strain DSM 34099.

The food enzyme ß-galactosidase (ß-d-galactoside galactohydrolase; EC 3.2.1.23) is produced with the genetically modified Bacillus licheniformis strain DSM 34099 by Kerry Group Services International, Ltd. (KGSI). The genetic modifications do not give rise to safety concerns. The food enzyme is free from viable cells of the production organism and its DNA. The production strain met the requirements for the qualified presumption of safety (QPS) approach. The food enzyme is intended to be used in two food manufacturing processes. Dietary exposure was estimated to be up to 7.263 mg total organic solids/kg body weight per day in European populations. Given the QPS status of the production strain and the absence of concerns resulting from the food enzyme manufacturing process, toxicity tests, other than an assessment of allergenicity, were considered unnecessary by the Panel. A search for the identity of the amino acid sequence of the food enzyme to known allergens was made and one match with a food allergen from kiwi fruit was found. The Panel considered that a risk of allergic reactions upon dietary exposure to this food enzyme, particularly in individuals sensitised to kiwi fruit, cannot be excluded. Based on the data provided, the Panel concluded that this food enzyme does not give rise to safety concerns, under the intended conditions of use.

Safety evaluation of the food enzyme ß-galactosidase from the non-genetically modified Kluyveromyces lactis strain GD-YNL.

The food enzyme ß-galactosidase (ß-D-galactoside galactohydrolase, EC 3.2.1.23) is produced with the non-genetically modified Kluyveromyces lactis strain GD-YNL by Godo Shusei Co., Ltd. The food enzyme is intended to be used for the hydrolysis of lactose in milk processing, production of fermented milk products and whey processing. The food enzyme is also intended for lactose hydrolysis in milk products at home. Dietary exposure to the food enzyme-total organic solids (TOS) was estimated to be up to 54 mg TOS/kg body weight per day in European populations. As the production strain qualifies for the qualified presumption of safety approach of safety assessment and as no issue of concern raised from the production process, no toxicological studies other than assessment of allergenicity were necessary. A search for the similarity of the amino acid sequence of the food enzyme to known allergens was made and no match was found. The Panel considered that, under the intended conditions of use, the risk of allergic reactions by dietary exposure cannot be excluded, but the likelihood is low. Based on the data provided, the Panel concluded that this food enzyme does not give rise to safety concerns under the intended conditions of use.

Safety evaluation of the food enzyme ß-galactosidase from the non-genetically modified Aspergillus oryzae strain AE-LA.

The food enzyme ß-galactosidase (ß-d-galactoside galactohydrolase; EC 3.2.1.23) is produced with the non-genetically modified Aspergillus oryzae strain AE-LA by Amano Enzyme Inc. The food enzyme was considered free from viable cells of the production organism. The food enzyme is intended to be used for lactose hydrolysis in milk processing, production of fermented milk products, whey processing and the manufacture of enzyme-modified dairy ingredients. Dietary exposure to the food enzyme-total organic solids (TOS) was estimated to be up to 1.651 mg TOS/kg body weight (bw) per day in European populations. Genotoxicity tests did not indicate a safety concern. The systemic toxicity was assessed by means of a repeated dose 90-day oral toxicity study in rats. The Panel identified a no observed adverse effect level of 1,656 mg TOS/kg bw per day, the highest dose tested. This results in a margin of exposure of at least 1,003. A search for similarity of the amino acid sequence of the food enzyme to known allergens was made and no match was found. The Panel considered that, under the intended conditions of use, the risk of allergic reactions by dietary exposure cannot be excluded, but the likelihood is considered to be low. Based on the data provided, the Panel concludes that this food enzyme does not give rise to safety concerns under the intended conditions of use.

Safety evaluation of the food enzyme ß-galactosidase from the non-genetically modified Kluyveromyces lactis strain GAL.

The food enzyme ß-galactosidase (ß-d-galactoside galactohydrolase; EC 3.2.1.23) is produced with the non-genetically modified Kluyveromyces lactis strain GAL by DSM Food Specialties B.V. It is intended to be used for the lactose hydrolysis in milk processing, production of fermented milk products and whey processing. It is also intended to be used for lactose hydrolysis in milk products at home. Dietary exposure to the food enzyme-total organic solids (TOS) was estimated to be up to 10.78 mg TOS/kg body weight per day in European populations. As the production strain of K. lactis strain GAL qualifies for the Qualified Presumption of Safety (QPS) approach to safety assessment and no issue of concern arose from the production process, no toxicological data are required. A search for similarity of the amino acid sequence of the food enzyme to known allergens was made and no match was found. The Panel considered that, under the intended conditions of use, the risk of allergic reactions by dietary exposure cannot be excluded, but the likelihood for this to occur is low. Based on the data provided, the Panel concluded that this food enzyme does not give rise to safety concerns under the intended conditions of use.

Safety evaluation of the food enzyme ß-galactosidase from the non-genetically modified Aspergillus sp. strain GD-FAL.

The food enzyme ß-galactosidase (EC 3.2.1.23) is produced with the non-genetically modified Aspergillus sp. strain GD-FAL by Godo Shusei Co., Ltd. The food enzyme is intended to be used in milk processing for the hydrolysis of lactose. The absence of viable cells of the production organism in the food enzyme was not demonstrated. Based on the assumption that all milk/dairy products are enzymatically treated, dietary exposure to the food enzyme-total organic solids (TOS) was estimated to be up to 0.301 mg TOS/kg body weight per day in European populations. The data provided did not allow concerns of genotoxicity of the food enzyme to be excluded. The systemic toxicity could not be assessed in the absence of an appropriate repeated dose 90-day oral toxicity study. Consequently, a margin of exposure was not calculated. A search for the similarity of the amino acid sequence of the food enzyme to known allergens was made and no match was found. The Panel considered that, under the intended conditions of use, the risk of allergic reactions by dietary exposure cannot be excluded, but the likelihood for this to occur is low. Based on the remaining concerns on genotoxicity, the inadequacies of the 90-day repeated dose oral toxicity study in rats and the missing data regarding the absence of viable cells of the production strain in the food enzyme, the Panel could not conclude on the safety of this food enzyme.

Safety evaluation of the food enzyme ß-galactosidase from the non-genetically modified Aspergillus oryzae strain GL 470.

The food enzyme ß-galactosidase (ß-d-galactoside galactohydrolase; EC 3.2.1.23) is produced with the Aspergillus oryzae strain GL 470 by Shin Nihon Chemical Co., Ltd. The food enzyme is free from viable cells of the production organism. It is intended to be used in five food manufacturing processes; lactose hydrolysis in milk processing, production of fermented milk products, whey processing, manufacture of enzyme-modified dairy ingredients and in the manufacture of galacto-oligosaccharides. Dietary exposure to the food enzyme-total organic solids (TOS) was estimated to be up to 1.388 mg TOS/kg body weight (bw) per day in European populations. Genotoxicity tests did not raise a safety concern. The systemic toxicity was assessed by means of repeated dose 90-day oral toxicity studies in rats. The Panel identified a no observed adverse effect level of 7,000 mg TOS/kg bw per day, the highest dose tested, which when compared with the estimated dietary exposure, results in a margin of exposure of at least 5,043. A search for similarity of the amino acid sequence of the food enzyme to known allergens was made and no match was found. The Panel concluded that, under the intended conditions of use, the risk of allergic reactions by dietary exposure cannot be excluded, but the likelihood for this to occur is considered to be low. Based on the data provided and considering the most recent complete toxicological data set, the Panel concluded that this food enzyme does not give rise to safety concerns under the intended conditions of use.

Safety evaluation of the use of the non-genetically modified Hamamotoa singularis strain YIT 10047 as a source of ß-galactosidase.

This assessment addresses the enzyme ß-galactosidase which is not separated from the yeast cells used for its production. The ß-galactosidase (ß-D-galactoside galactohydrolase, EC 3.2.1.23) is produced with the non-genetically modified Hamamotoa singularis (formerly Sporobolomyces singularis) strain YIT 10047 by Yakult Pharmaceutical Industry Co., Ltd. The yeast cell suspension contains both live and dead yeast cells. It is intended to be used in the production of galacto-oligosaccharides (GOS). The final GOS products are free of viable cells of the H. singularis. Dietary exposure to the food enzyme total organic solids (TOS) was estimated to be up to 0.683 mg TOS/kg body weight (bw) per day in European populations. Genotoxicity tests of the cell suspension did not indicate a safety concern. The systemic toxicity was assessed by means of a repeated dose 90-day oral toxicity study in rats. The Panel identified a no observed adverse effect level of 296.25 mg TOS/kg bw per day, the highest dose tested. This results in a margin of exposure above 434. A search for the similarity of the amino acid sequence of the ß-galactosidase to known allergens was made and no matches were found. The Panel considered that, under the intended conditions of use, the risk of allergic reactions by dietary exposure cannot be excluded, but the likelihood for this to occur is low. Based on the data provided, the Panel concluded that this yeast suspension used as a source of ß-galactosidase does not give rise to safety concerns under the intended conditions of use.

ß-Galactosidase deficiency in the GLB1 spectrum of lysosomal storage disease can present with severe muscle weakness and atrophy.

Deficiency of the enzyme ß-galactosidase due to variants in the GLB1-gene is associated with metabolic disorders: Morquio B and GM1-gangliosidosis. Here, we report a case compound heterozygous for variants in the GLB1-gene and a severe muscular phenotype. Full body T1-w MRI was conducted for muscular involvement. Biopsy was stained with hematoxylin and eosin for histopathological evaluation. EDTA blood-sample was subjected to whole exome sequencing. Metabolic analysis included residual enzyme activity and evaluation urinary substrate secretion. Additionally, electroneurography, echocardiography, forced volume capacity and biochemistry were evaluated. Examination showed severe proximal weakness (MRC: hip flexion 2, hip extension 2, and shoulder rotation 2), Gower's sign, no extrapyramidal symptoms and normal creatine kinase levels. MRI showed severe muscle wasting of the thigh and shoulder girdle. Muscle biopsy showed mild myopathic changes. ß-galactosidase activity was reduced to 28%-34%. Urinary glycosaminoglycan was elevated by 5.9-8.6 mg/mmol (ref.:0-5.1 mg/mmol). Electrophoresis indicated excess keratan sulfate. Exome sequencing revealed two missense variants in the GLB1 gene. Clinical features, genetic testing and laboratory findings indicate a case of ß-galactosidase-deficiency with a muscular phenotype.

Safety evaluation of the food enzyme ß-galactosidase from the genetically modified Kluyveromyces lactis strain KLA.

The food enzyme ß-galactosidase (ß-d-galactoside galactohydrolase; EC 3.2.1.23) is produced with the genetically modified Kluyveromyces lactis strain KLA by DSM Food Specialties B.V. The genetic modifications did not give rise to safety concerns. The food enzyme was considered free from viable cells of the production organism and its DNA. The food enzyme is intended to be used for the lactose hydrolysis in milk processing, production of fermented milk products and whey processing. It is also intended for lactose hydrolysis in milk products at home. Dietary exposure to the food enzyme-total organic solids (TOS) was estimated to be up to 11.876 mg TOS/kg body weight per day in European populations. The production strain of the food enzyme fulfils the requirements for the Qualified Presumption of Safety (QPS) approach to safety assessment. As no concerns arising from its genetic modification or from the manufacturing process have been identified, the Panel considered that toxicological tests are not needed for the assessment of this food enzyme. A search for similarity of the amino acid sequence of the food enzyme to known allergens was made and no match was found. The Panel considered that, under the intended conditions of use, the risk of allergic reactions by dietary exposure cannot be excluded, but the likelihood for this to occur is low. The Panel concluded that this food enzyme does not give rise to safety concerns under the intended conditions of use.

Safety evaluation of the food enzyme ß-galactosidase from the non-genetically modified Neobacillus sp. strain AE-LT.

The food enzyme ß-galactosidase (EC 3.2.1.23) is produced with the non-genetically modified Neobacillus sp. strain AE-LT by Amano Enzyme Inc. The strain is not cytotoxic and does not harbour any known virulence factor or antimicrobial resistance gene. The presence of viable cells of the production strain in the food enzyme could not be excluded, but the likelihood of this being a hazard is considered low. The food enzyme is intended to be used for lactose hydrolysis in milk processing and the manufacture of galacto-oligosaccharides (GOS). The dietary exposure to the food enzyme-total organic solids (TOS) was estimated to be up to 2.971 mg TOS/kg body weight (bw) per day in European populations. Genotoxicity tests did not raise a safety concern. The systemic toxicity was assessed by means of a repeated dose 90-day oral toxicity study in rats. The Panel identified a no observed adverse effect level of 1,223 mg TOS/kg bw per day, the highest dose tested, which when compared with the estimated dietary exposure, results in a margin of exposure of at least 412. A search for similarity of the amino acid sequence of the food enzyme to known allergens was made and no match was found. The Panel considered that, under the intended conditions of use, the risk of allergic reactions by dietary exposure cannot be excluded, but the likelihood for this to occur is low. Based on the data provided, the Panel concluded that this food enzyme does not give rise to safety concerns under the intended conditions of use.

Safety evaluation of the food enzyme ß-galactosidase from the non-genetically modified Kluyveromyces lactis strain AE-KL.

The food enzyme ß-galactosidase (ß-d-galactoside galatohydrolase, EC 3.2.1.23) is produced with the non-genetically modified Kluyveromyces lactis strain AE-KL by Amano Enzyme Inc. As the production strain meets the requirements for a Qualified Presumption of Safety (QPS) approach to safety assessment and as no other issues of concern were identified, the Panel considered that toxicological tests were not needed for the assessment of this food enzyme. The food enzyme is intended to be used for lactose hydrolysis in milk processing (including infant formulae), production of fermented milk products and manufacture of galacto-oligosaccharides (GOS). The dietary exposure to the food enzyme-total organic solids (TOS) was estimated to be up to 7.933 mg TOS/kg body weight (bw) per day in European populations. A search for similarity of the amino acid sequence of the food enzyme to known allergens was made and no match was found. The Panel considered that, under the intended conditions of use, the risk of allergic reactions by dietary exposure cannot be excluded, but the likelihood for this to occur is considered to be low. Based on the QPS status of the production strain and the data provided, the Panel concluded that this food enzyme does not give rise to safety concerns, under the intended conditions of use.

Safety evaluation of the food enzyme ß-galactosidase from the genetically modified Aspergillus niger strain TOL.

The food enzyme ß-galactosidase (ß-D-galactoside galactohydrolase; EC 3.2.1.23) is produced with the genetically modified Aspergillus niger strain TOL by DSM Food Specialties B.V. The genetic modifications did not give rise to safety concerns. The food enzyme was considered free from viable cells of the production organism and recombinant DNA. The food enzyme is intended to be used in whey processing. Dietary exposure to the food enzyme total organic solids (TOS) was estimated to be up to 0.197 mg TOS/kg body weight (bw) per day in European populations. The toxicity studies were carried out with an asparaginase from A. niger strain ASP. The Panel considered this food enzyme as a suitable substitute for the ß-galactosidase to be used in the toxicological studies, because the genetic differences between the production strains are not expected to result in a different toxigenic potential and the raw materials and manufacturing processes of both food enzymes are comparable. Genotoxicity tests did not raise a safety concern. The systemic toxicity was assessed by means of a repeated dose 90-day oral toxicity study in rats. The Panel identified a no observed adverse effect level of 1,038 mg TOS/kg bw per day, the highest dose tested. This results in a margin of exposure of at least 5,269. A search for similarity of the amino acid sequence of the food enzyme to known allergens was made and no match was found. The Panel considered that, under the intended conditions of use, the risk of allergic reactions by dietary exposure cannot be excluded, but the likelihood for this to occur is considered low. Based on the data provided, the Panel concluded that this food enzyme does not give rise to safety concerns under the intended conditions of use.