RESUMO
BACKGROUND: The aim of this study was to evaluate the efficacy and safety of formula milk powder in the treatment of lactose intolerance in children, and to provide an evidence-based medicine basis for the rational use of drugs in children with lactose intolerance caused by various reasons by meta-analysis. METHODS: Use computers to search major databases, including Web of Science, PubMed, CNKI, Wanfang Data Knowledge Service Platform, and other databases, the retrieval time is from the establishment of the database to April 2023. The collected literatures were screened, data extracted and processed, and then meta-analysis was performed by Review-Manager 5.4 statistical software. RESULTS: A total of 10 randomized controlled trials were included, with 1112 patients, including 562 patients in the treatment group and 550 patients in the control group. The control group was treated with conventional therapy, and the treatment group was treated with lactose-free/low-lactose milk powder on the basis of conventional therapy. The results of the meta-analysis showed that the clinical efficacy of the treatment group was significantly better than that of the control group [odds ratio=6.01, 95% confidence interval (CI): 3.94-9.18, P<0.00001], the course of disease in the treatment group was shorter than that in the control group (mean difference=-1.45, 95% CI: -1.76 to -1.13, P<0.0001). The antidiarrhea time of the treatment group was shorter than that of the control group, and the difference between the 2 groups was statistically significant (mean difference=-1.41, 95% CI: -1.67 to -1.15, P<0.0001). CONCLUSION: Low/lactose-free milk powder can improve clinical efficacy and shorten the course of treatment in infants with lactose intolerance, which can be demonstrated by further large-scale clinical studies.
Assuntos
Intolerância à Lactose , Metanálise como Assunto , Revisões Sistemáticas como Assunto , Humanos , Intolerância à Lactose/dietoterapia , Lactente , Fórmulas Infantis , Lactose , Leite , Ensaios Clínicos Controlados Aleatórios como Assunto , Pós , Resultado do Tratamento , AnimaisRESUMO
α -Lactalbumin, an abundant protein present in the milk of most mammals, is associated with biological, nutritional and technological functionality. Its sequence presents N-glycosylation motifs, the occupancy of which is species-specific, ranging from no to full occupancy. Here, we investigated the N-glycosylation of bovine α-lactalbumin in colostrum and milk sampled from four individual cows, each at 9 time points starting from the day of calving up to 28.0 d post-partum. Using a glycopeptide-centric mass spectrometry-based glycoproteomics approach, we identified N-glycosylation at both Asn residues found in the canonical Asn-Xxx-Ser/Thr motif, i.e. Asn45 and Asn74 of the secreted protein. We found similar glycan profiles in all four cows, with partial site occupancies, averaging at 35% and 4% for Asn45 and Asn74, respectively. No substantial changes in occupancy occurred over lactation at either site. Fucosylation, sialylation, primarily with N-acetylneuraminic acid (Neu5Ac), and a high ratio of N,N'-diacetyllactosamine (LacdiNAc)/N-acetyllactosamine (LacNAc) motifs were characteristic features of the identified N-glycans. While no substantial changes occurred in site occupancy at either site during lactation, the glycoproteoform (i.e. glycosylated form of the protein) profile revealed dynamic changes; the maturation of the α-lactalbumin glycoproteoform repertoire from colostrum to mature milk was marked by substantial increases in neutral glycans and the number of LacNAc motifs per glycan, at the expense of LacdiNAc motifs. While the implications of α-lactalbumin N-glycosylation on functionality are still unclear, we speculate that N-glycosylation at Asn74 results in a structurally and functionally different protein, due to competition with the formation of its two intra-molecular disulphide bridges.
Assuntos
Colostro , Lactalbumina , Leite , Lactalbumina/metabolismo , Lactalbumina/química , Animais , Glicosilação , Colostro/química , Colostro/metabolismo , Bovinos , Leite/química , Leite/metabolismo , Feminino , Lactação/metabolismo , Amino Açúcares/química , Amino Açúcares/metabolismo , Glicopeptídeos/metabolismo , Glicopeptídeos/química , Glicopeptídeos/análise , Lactose/metabolismo , Lactose/químicaRESUMO
The quality of a cheese is determined by the balance of aroma compounds primarily produced by microorganisms during the transformation of milk into ripened cheese. The microorganisms, along with the technological parameters used in cheese production, influence aroma formation. The perception of these compounds is further influenced by the composition and structure of the cheese. This study aimed to characterize how cheese composition affects aroma compound production, release, and perception. Sixteen cheeses were produced under controlled conditions, followed by a quantitative descriptive analysis post ripening. Aroma composition was analyzed using HS-SPME-GC-MS, and a dynamic sensory evaluation (TCATA) was combined with nosespace analysis using PTR-ToF-MS. Image analysis was also conducted to characterize cheese structure. Cheese fat and whey lactose contents were identified as key factors in the variability of sensory attributes. GC-MS analyses identified 27 compounds correlated with sensory attributes. In terms of aroma compound release, 23 ions were monitored, with fat, salt, and lactose levels significantly affecting the release of most compounds. Therefore, cheese fat, salt, and whey lactose levels, as well as the types of microbial strains, play a role in influencing the composition, structure, release of aroma compounds, and sensory perception.
Assuntos
Queijo , Cromatografia Gasosa-Espectrometria de Massas , Odorantes , Compostos Orgânicos Voláteis , Queijo/análise , Queijo/microbiologia , Odorantes/análise , Compostos Orgânicos Voláteis/análise , Lactose/análise , Humanos , AnimaisRESUMO
Responsible use of natural resources and waste reduction are key concepts in bioeconomy. This study demonstrates that agro-food derived-biomasses from the Italian food industry, such as crude glycerol and cheese whey permeate (CWP), can be combined in a high-density fed-batch culture to produce a recombinant ß-galactosidase from Marinomonas sp. ef1 (M-ßGal). In a small-scale process (1.5 L) using 250 mL of crude glycerol and 300 mL of lactose-rich CWP, approximately 2000 kU of recombinant M-ßGal were successfully produced along with 30 g of galactose accumulated in the culture medium. The purified M-ßGal exhibited high hydrolysis efficiency in lactose-rich matrices, with hydrolysis yields of 82 % in skimmed milk at 4 °C and 94 % in CWP at 50 °C, highlighting its biotechnological potential. This approach demonstrates the effective use of crude glycerol and CWP in sustainable and cost-effective high-density Escherichia coli cultures, potentially applicable to recombinant production of various proteins.
Assuntos
Biotecnologia , Queijo , Escherichia coli , Glicerol , Soro do Leite , beta-Galactosidase , Glicerol/metabolismo , beta-Galactosidase/metabolismo , Escherichia coli/metabolismo , Biotecnologia/métodos , Proteínas Recombinantes/metabolismo , Hidrólise , Técnicas de Cultura Celular por Lotes , Lactose/metabolismoRESUMO
The frequent mutations of influenza A virus (IAV) have led to an urgent need for the development of innovative antiviral drugs. Glycopolymers offer significant advantages in biomedical applications owing to their biocompatibility and structural diversity. However, the primary challenge lies in the design and synthesis of well-defined glycopolymers to precisely control their biological functionalities. In this study, functional glycopolymers with sulfated fucose and 6'-sialyllactose were successfully synthesized through ring-opening metathesis polymerization and a postmodification strategy. The optimized heteropolymer exhibited simultaneous targeting of hemagglutinin and neuraminidase on the surface of IAV, as evidenced by MU-NANA assay and hemagglutination inhibition data. Antiviral experiments demonstrated that the glycopolymer displayed broad and efficient inhibitory activity against wild-type and mutant strains of H1N1 and H3N2 subtypes in vitro, thereby establishing its potential as a dual-targeted inhibitor for combating IAV resistance.
Assuntos
Antivirais , Fucose , Vírus da Influenza A Subtipo H1N1 , Lactose , Antivirais/farmacologia , Antivirais/química , Antivirais/síntese química , Lactose/análogos & derivados , Lactose/química , Lactose/farmacologia , Fucose/química , Fucose/análogos & derivados , Fucose/farmacologia , Vírus da Influenza A Subtipo H1N1/efeitos dos fármacos , Vírus da Influenza A Subtipo H3N2/efeitos dos fármacos , Farmacorresistência Viral/efeitos dos fármacos , Humanos , Neuraminidase/antagonistas & inibidores , Neuraminidase/metabolismo , Vírus da Influenza A/efeitos dos fármacos , Células Madin Darby de Rim Canino , Animais , Cães , Polímeros/farmacologia , Polímeros/químicaRESUMO
The use of lactose and cow milk protein (CMP) as potential allergens in pharmaceuticals and their ability to cause allergic reactions remains a significant concern in medicine. Lactose, a common pharmaceutical excipient due to its inert, inexpensive, and stable properties, is found in many prescription-only and over-the-counter medications. However, despite their widespread use, individuals with lactose intolerance (LI) or cow milk protein allergy (CMPA) may experience adverse reactions to these excipients. This study investigated the prevalence of lactose and other dairy-derived ingredients in pharmaceuticals marketed in Portugal. Using the Summary of Product Characteristics (SmPC) from the INFOMED database, various medications, including analgesics, antipyretics, non-steroidal anti-inflammatory drugs (NSAIDs), and antiasthmatics, were analyzed. Results showed a high prevalence of dairy-derived excipients, particularly in antiasthmatic drugs (62.6%) and NSAIDs (39%). Although CMP are not explicitly mentioned in SmPCs, the presence of lactose as an ingredient poses a risk of cross-contamination. The findings emphasize the need for healthcare professionals to be aware of potential allergens in medications and the importance of developing lactose-free alternatives to ensure the safety of patients with LI and CMPA. Further research is required to assess the safety and implications of lactose in medicines for these populations.
Assuntos
Excipientes , Intolerância à Lactose , Lactose , Hipersensibilidade a Leite , Humanos , Excipientes/efeitos adversos , Excipientes/química , Hipersensibilidade a Leite/epidemiologia , Animais , Lactose/efeitos adversos , Lactose/análise , Lactose/química , Bovinos , Proteínas do Leite/efeitos adversos , Anti-Inflamatórios não Esteroides/efeitos adversos , Anti-Inflamatórios não Esteroides/análise , Alérgenos/análise , Portugal , Laticínios/análise , Laticínios/efeitos adversosRESUMO
BACKGROUND: The milk's nutritional value is determined by its constituents, including fat, protein, carbohydrates, and minerals. The mammary gland's ability to produce milk is controlled by a complex network of genes. Thereby, the fat, protein, and lactose synthesis must be boost in milk to increase milk production efficiency. This can be accomplished by fusing genetic advancements with proper management practices. Therefore, this study aimed to investigate the association between the Lipoprotein lipase (LPL), kappa casein CSN3, and Glucose transporter 1 (GLUT1) genes expression levels and such milk components as fat, protein, and lactose in different dairy breeds during different stages of lactation. METHODS: To achieve such a purpose, 94 milk samples were collected (72 samples from 36 multiparous black-white and red-white Holstein-Friesian (HF) cows and 22 milk samples from 11 Egyptian buffaloes) during the early and peak lactation stages. The milk samples were utilized for milk analysis and genes expressions analyses using non- invasive approach in obtaining milk fat globules (MFGs) as a source of Ribonucleic acid (RNA). RESULTS: LPL and CSN3 genes expressions levels were found to be significantly higher in Egyptian buffalo than Holstein-Friesian (HF) cows as well as fat and protein percentages. On the other hand, GLUT1 gene expression level was shown to be significantly higher during peak lactation than early lactation. Moreover, lactose % showed a significant difference in peak lactation phase compared to early lactation phase. Also, fat and protein percentages were significantly higher in early lactation period than peak lactation period but lactose% showed the opposite pattern of Egyptian buffalo. CONCLUSION: Total RNA can be successfully obtained from MFGs. The results suggest that these genes play a role in glucose absorption and lactose synthesis in bovine mammary epithelial cells during lactation. Also, these results provide light on the differential expression of these genes among distinct Holstein-Friesian cow breeds and Egyptian buffalo subspecies throughout various lactation phases.
Assuntos
Caseínas , Glicolipídeos , Glicoproteínas , Lactação , Gotículas Lipídicas , Glândulas Mamárias Animais , Leite , RNA Mensageiro , Animais , Bovinos/genética , Lactação/genética , Feminino , Gotículas Lipídicas/metabolismo , Leite/química , Leite/metabolismo , Glicolipídeos/metabolismo , Caseínas/genética , Caseínas/metabolismo , Glicoproteínas/genética , Glicoproteínas/metabolismo , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Glândulas Mamárias Animais/metabolismo , Lipase Lipoproteica/genética , Lipase Lipoproteica/metabolismo , Transportador de Glucose Tipo 1/genética , Transportador de Glucose Tipo 1/metabolismo , Búfalos/genética , Búfalos/metabolismo , Lactose/metabolismo , Lactose/análise , Proteínas do Leite/análise , Proteínas do Leite/metabolismo , Proteínas do Leite/genética , Regulação da Expressão GênicaRESUMO
Galectins are multifunctional effectors in cellular homeostasis and dysregulation. Oxidation of human galectin-1 (Gal-1) with its six sulfhydryls produces a disulfide-bridged oxidized form that lacks normal lectin activity yet gains new glycan-independent functionality. Nevertheless, the mechanistic details as to how Gal-1 oxidation occurs remain unclear. Here, we used 15N and 13C HSQC NMR spectroscopy to gain structural insight into the CuSO4-mediated path of Gal-1 oxidation and identified a minimum two-stage conversion process. During the first phase, disulfide bridges form slowly between C16-C88 and/or C42-C66 to produce a partially oxidized, conformationally flexible intermediate that retains the ability to bind lactose. Site-directed mutagenesis of C16 to S16 impedes the onset of this overall slow process. During the second phase, increased motional dynamics of the intermediate enable the relatively distant C2 and C130 residues to form the third and final disulfide bond, leading to an unfolded state and consequent dimer dissociation. This fully oxidized end state loses the ability to bind lactose, as shown by the hemagglutination assay. Consistent with this model, we observed that the Gal-1 C2S mutant maintains intermediate-state structural features with a free sulfhydryl group at C130. Incubation with dithiothreitol reduces all disulfide bonds and allows the lectin to revert to its native state. Thus, the sequential, non-random formation of three disulfide bridges in Gal-1 in an oxidative environment acts as a molecular switch for fundamental changes to its functionality. These data inspire detailed bioactivity analysis of the structurally defined oxidized intermediate in, e.g., acute and chronic inflammation.
Assuntos
Cisteína , Galectina 1 , Oxirredução , Galectina 1/metabolismo , Galectina 1/química , Galectina 1/genética , Humanos , Cisteína/metabolismo , Cisteína/química , Dissulfetos/metabolismo , Dissulfetos/química , Dobramento de Proteína , Desdobramento de Proteína , Modelos Moleculares , Lactose/metabolismo , Lactose/química , Mutagênese Sítio-DirigidaRESUMO
The cholecystokinin type 2 receptor (CCK2-R) represents an ideal target for cancer therapy since it is overexpressed in several tumors and is associated with poor prognosis. Nastorazepide (Z-360), a selective CCK2-R antagonist, has been widely investigated as a CCK2-R ligand for targeted therapy; however, its high hydrophobicity may represent a limit to cell selectivity and optimal in vivo biodistribution. Here, we present three new fluorescent Z-360 derivatives (IP-002G-Rho, IP-002L-Rho, and IP-002M-Rho) in which nastorazepide was linked, through spacers bearing different saccharides (glucose (G), lactose (L), and maltotriose (M)), to sulforhodamine B. A fourth compound (IP-002H-Rho) with no pendant sugar was also synthesized as a control. Through two-dimensional (2D) and three-dimensional (3D) in vitro studies, we evaluated the compound association with and selectivity for CCK2-R-overexpressing cells (A431-CCK2-R+) vs CCK2-R-underexpressing cells (A431 WT). 2D in vitro studies highlighted a progressive increase of IP-002x-Rho association with A431-CCK2-R+ cells according to the linker hydrophilicity, that is, maltotriose > lactose > glucose > hydrogen, with IP-002M-Rho showing a 2.4- and a 1.36-fold higher uptake than IP-002G-Rho and IP-002L-Rho, respectively. Unexpectedly, IP-002H-Rho showed a similar cell association to that of IP-002L-Rho but with no difference between the two tested cell lines. On the contrary, association with A431-CCK2-R+ cells as compared to the A431 WT was found to be 1.08-, 1.14-, and 1.37-fold higher for IP-002G-Rho, IP-002L-Rho, and IP-002M-Rho, respectively, proving IP-002M-Rho to be the best-performing compound, as also confirmed by competition studies. Trafficking studies on A431-CCK2-R+ cells incubated with IP-002M-Rho suggested the coexistence of receptor-mediated endocytosis and simple diffusion. On the contrary, a high and selective uptake of IP-002M-Rho by A431-CCK2-R+ cells only was observed on 3D scaffolds embedded with cells, underlining the importance of 3D models in in vitro preliminary evaluation.
Assuntos
Receptor de Colecistocinina B , Humanos , Receptor de Colecistocinina B/antagonistas & inibidores , Receptor de Colecistocinina B/metabolismo , Linhagem Celular Tumoral , Trissacarídeos/química , Lactose/análogos & derivados , Lactose/química , Glucose/metabolismoRESUMO
Negative energy balance (NEB) is a serious problem in most dairy cows. It occurs most frequently after calving, when cows are unable to consume sufficient DM to meet their energy requirements during early lactation. During NEB, the breakdown of fat stores releases non-esterified fatty acids (NEFAs) into the bloodstream. High blood concentrations of NEFAs cause health problems such as ketosis, fatty liver syndrome, and enhanced susceptibility to infections. These issues may substantially increase premature culling from the herd. Serum NEFA concentrations are often used as a direct marker of energy metabolism. However, because the direct measurement of serum NEFAs is difficult under commercial conditions, alternative indicators, such as milk components, have been increasingly investigated for their use in estimating energy balance. The objectives of this study were to (1) evaluate the relationships between serum NEFA concentrations and selected milk components in cows from two farms during the first 5 weeks of lactation, and to (2) develop a model valid for both herds for predicting serum NEFA concentrations using milk components. A total of 121 lactating Holstein cows from two different farms were included in the experiment. Blood samples were collected for NEFA analysis on days 7 (± 3), 14 (± 3), 21 (± 3), and 35 (± 3) after calving. Composite milk samples were collected during afternoon milking on the same days as blood sampling. Concentrations of fat, protein, lactose, and milk fatty acids (FAs) were determined using Fourier-transform IR spectroscopy analysis. The strongest correlations (r > 0.43) were recorded between serum NEFAs and milk long-chain FAs, monounsaturated FAs, C18:0, and C18:1 within each farm and for both farms combined. Two prediction models for serum log(NEFA) using milk components as predictors were developed by stepwise regression. The prediction model with the best fit (R2 = 0.52) included days in milk, fat-to-protein ratio, and C18:1, C18:12 and C14:0 expressed as g/100 g of milk fat. An essential finding is that, despite different concentrations of NEFAs, and of most milk components observed in the evaluated herds, there were no significant interactions between farm and any of the FAs, so the same regression coefficients could be used for the prediction models in both farms. Validation of these findings in a greater number of herds would allow for the use of milk FAs to identify energy-imbalanced cows in herds under different farm conditions.
Assuntos
Metabolismo Energético , Ácidos Graxos não Esterificados , Lactação , Leite , Animais , Bovinos , Feminino , Ácidos Graxos não Esterificados/sangue , Ácidos Graxos não Esterificados/análise , Leite/química , Leite/metabolismo , Indústria de Laticínios , Proteínas do Leite/análise , Lactose/análise , FazendasRESUMO
In this study, the cellobiose 2-epimerase gene csce from Caldicellulosiruptor saccharolyticus was expressed in Escherichia coli using TB medium containing yeast extract Oxoid and tryptone Oxoid. Interesting, it was found that when the concentration of isopropyl-beta-d-thiogalactopyranoside (IPTG) and lactose was 0 (no addition), the activity of cellobiose 2-epimerase reached 5.88 U/mL. It was 3.70-fold higher than the activity observed when 1.0 mM IPTG was added. When using M9 medium without yeast extract Oxoid and tryptone Oxoid, cellobiose 2-epimerase gene could not be expressed without IPTG and lactose. However, cellobiose 2-epimerase gene could be expressed when yeast extract Oxoid or tryptone Oxoid was added, indicating that these supplements contained inducers for gene expression. In the absence of IPTG and lactose, the addition of soy peptone Angel-1 or yeast extract Angel-1 to M9 medium significantly upregulated the expression of cellobiose 2-epimerase gene in E. coli BL21 pET28a-csce, and these inductions led to higher expression levels compared to tryptone Oxoid or yeast extract Oxoid. The relative transcription level of csce was consistent with its expression level in E. coli BL21 pET28a-csce. In the medium TB without IPTG and lactose and containing yeast extract Angel-1 and soy peptone Angel-1, the activity of cellobiose 2-epimerase reached 6.88 U/mL, representing a 2.2-fold increase compared to previously reported maximum activity in E. coli. The significance of this study lies in its implications for efficient heterologous expression of recombinant enzyme proteins in E. coli without the need for IPTG and lactose addition.
Assuntos
Carboidratos Epimerases , Celobiose , Escherichia coli , Lactose , Escherichia coli/genética , Escherichia coli/metabolismo , Lactose/metabolismo , Carboidratos Epimerases/genética , Carboidratos Epimerases/metabolismo , Carboidratos Epimerases/biossíntese , Celobiose/metabolismo , Proteínas Recombinantes/genética , Proteínas Recombinantes/biossíntese , Proteínas Recombinantes/metabolismo , Isopropiltiogalactosídeo/farmacologia , Regiões Promotoras Genéticas , Expressão Gênica , Proteínas de Bactérias/genética , Proteínas de Bactérias/biossíntese , Proteínas de Bactérias/metabolismoRESUMO
6'-Sialyllactose (6'-SL), the most abundant sialylated human milk oligosaccharide, has attracted attention for its potential application in supplementary infant formulas. Herein, we report a facile strategy to construct a cascade bioreactor for the enzymatic synthesis of 6'-SL by co-immobilizing an enzymatic module consisting of CMP-sialic acid synthase and α-2,6-sialyltransferase into hierarchically porous MIL-53 (HP-MIL-53). The as-prepared HP-MIL-53 showed high enzyme immobilization capacity, reaching 226 mg g-1. Furthermore, the co-immobilized enzymes exhibited higher initial catalytic efficiency, and thermal, pH and storage stability than the free ones. Finally, the 6'-SL yield remained >80% after 13 cycles of use. We expect that HP-MIL-53 would have potential industrial applications in the enzymatic modular synthesis of 6'-SL and other glycans.
Assuntos
Enzimas Imobilizadas , Sialiltransferases , Enzimas Imobilizadas/química , Enzimas Imobilizadas/metabolismo , Sialiltransferases/metabolismo , Porosidade , Humanos , Oligossacarídeos/química , Oligossacarídeos/metabolismo , Oligossacarídeos/biossíntese , N-Acilneuraminato Citidililtransferase/metabolismo , N-Acilneuraminato Citidililtransferase/química , Reatores Biológicos , Leite Humano/química , Leite Humano/metabolismo , Lactose/química , Lactose/análogos & derivados , Lactose/metabolismo , Concentração de Íons de Hidrogênio , beta-D-Galactosídeo alfa 2-6-SialiltransferaseRESUMO
Sialylation during N-glycosylation plays an important role in the half-life of therapeutic glycoproteins in vivo and has sparked interest in the production of therapeutic proteins using recombinant Chinese hamster ovary (rCHO) cells. To improve the sialylation of therapeutic proteins, we examined the effect of sialyllactose supplementation on sialylation of Fc-fusion glycoproteins produced in rCHO cells. Two enzymatically-synthesized sialyllactoses, 3'-sialyllactose (3'-SL) and 6'-sialyllactose (6'-SL), were administered separately to two rCHO cell lines producing the same Fc-fusion glycoprotein derived from DUKX-B11 and DG44, respectively. Two sialyllactoses successfully increased sialylation of Fc-fusion glycoprotein in both cell lines, as evidenced by isoform distribution, sialylated N-glycan formation, and sialic acid content. Increased sialylation by adding sialyllactose was likely the result of increased amount of intracellular CMP-sialic acid (CMP-SA), the direct nucleotide sugar for sialylation. Furthermore, the degree of sialylation enhanced by sialyllactoses was slightly effective or nearly similar compared with the addition of N-acetylmannosamine (ManNAc), a representative nucleotide sugar precursor, to increase sialylation of glycoproteins. The effectiveness of sialyllactose was also confirmed using three commercially available CHO cell culture media. Taken together, these results suggest that enzymatically-synthesized sialyllactose represents a promising candidate for culture media supplementation to increase sialylation of glycoproteins in rCHO cell culture.
Assuntos
Cricetulus , Fragmentos Fc das Imunoglobulinas , Lactose , Animais , Células CHO , Lactose/análogos & derivados , Lactose/metabolismo , Fragmentos Fc das Imunoglobulinas/genética , Fragmentos Fc das Imunoglobulinas/metabolismo , Cricetinae , Glicosilação , Proteínas Recombinantes de Fusão/metabolismo , Proteínas Recombinantes de Fusão/genética , Glicoproteínas/metabolismo , Glicoproteínas/genética , Meios de Cultura/química , Ácidos Siálicos/metabolismo , Ácido N-Acetilneuramínico/metabolismo , OligossacarídeosRESUMO
Structural variation of N-glycans is essential for the regulation of glycoprotein functions. GalNAcß1-4GlcNAc (LacdiNAc or LDN), a unique subterminal glycan structure synthesized by B4GALNT3 or B4GALNT4, is involved in the clearance of N-glycoproteins from the blood and maintenance of cell stemness. Such regulation of glycoprotein functions by LDN is largely different from that by the dominant subterminal structure, N-acetyllactosamine (Galß1-4GlcNAc, LacNAc). However, the mechanisms by which B4GALNT activity is regulated and how LDN plays different roles from LacNAc remain unclear. Here, we found that B4GALNT3 and four have unique domain organization containing a noncatalytic PA14 domain, which is a putative glycan-binding module. A mutant lacking this domain dramatically decreases the activity toward various substrates, such as N-glycan, O-GalNAc glycan, and glycoproteins, indicating that this domain is essential for enzyme activity and forms part of the catalytic region. In addition, to clarify the mechanism underlying the functional differences between LDN and LacNAc, we examined the effects of LDN on the maturation of N-glycans, focusing on the related glycosyltransferases upstream and downstream of B4GALNT. We revealed that, unlike LacNAc synthesis, prior formation of bisecting GlcNAc in N-glycan almost completely inhibits LDN synthesis by B4GALNT3. Moreover, the presence of LDN negatively impacted the actions of many glycosyltransferases for terminal modifications, including sialylation, fucosylation, and human natural killer-1 synthesis. These findings demonstrate that LDN has significant impacts on N-glycan maturation in a completely different way from LacNAc, which could contribute to obtaining a comprehensive overview of the system regulating complex N-glycan biosynthesis.
Assuntos
N-Acetilgalactosaminiltransferases , Polissacarídeos , Humanos , Polissacarídeos/metabolismo , N-Acetilgalactosaminiltransferases/metabolismo , N-Acetilgalactosaminiltransferases/genética , Domínios Proteicos , Glicoproteínas/metabolismo , Glicoproteínas/genética , Glicoproteínas/química , Lactose/análogos & derivadosRESUMO
ß-D-galactosidase is a hydrolase enzyme capable of hydrolyzing lactose in milk-based foods. Its free form can be inactivated in solution during the production of low-dosage lactose foods. Then, it is important to study strategies for avoiding the free enzyme inactivation with the aim of circumventing this problem. The stabilization of ß-D-galactosidase in aqueous solution after interactions with chitosan/eucalyptus sawdust composite membrane proved to be a potential strategy when optimized by central composite rotatable (CCR) design. In this case, the best experimental conditions for ß-D-galactosidase partitioning and stability in an aqueous medium containing the chitosan-based composite membrane reinforced with eucalyptus sawdust were i) enzyme/buffer solution ratio of 0.0057, ii) pH 5.6, iii) membrane mass of 50 mg, and iv) temperature lower than 37 °C. Significance was found for the linear enzyme/buffer solution ratio, linear temperature, and quadratic pH (p < 0.05) in the interval between 0 and 60 min of study. In the interval between 60 and 120 min, there was significance (p < 0.12) for linear temperature, the temperature-enzyme/buffer solution ratio interaction and the interaction between linear pH and linear enzyme/buffer solution ratio. The Pareto charts and response surfaces clearly showed all the effects of the experimental variables on the stabilization of ß-D-galactosidase in solution after interactions with the chitosan composite membrane. In this case, industrial food reactors covered with chitosan/eucalyptus sawdust composite membrane could be a strategy for the hydrolysis of lactose during milk-producing processes.
Assuntos
Quitosana , Estabilidade Enzimática , beta-Galactosidase , Quitosana/química , beta-Galactosidase/química , beta-Galactosidase/metabolismo , Concentração de Íons de Hidrogênio , Membranas Artificiais , Soluções , Temperatura , Lactose/químicaRESUMO
Lactulose is a semisynthetic nondigestive sugar derived from lactose, with wide applications in the food and pharmaceutical industries. Its biological production routes which use cellobiose 2-epimerase (C2E) as the key enzyme have attracted widespread attention. In this study, a set of C2Es from different sources were overexpressed in Escherichia coli to produce lactulose. We obtained a novel and highly efficient C2E from Clostridium disporicum (CDC2E) to synthesize lactulose from lactose. The effects of different heat treatment conditions, reaction pH, reaction temperature, and substrate concentrations were investigated. Under the optimum biotransformation conditions, the final concentration of lactulose was up to 1.45â¯M (496.3â¯g/L), with a lactose conversion rate of 72.5â¯%. This study provides a novel C2E for the biosynthesis of lactulose from low-cost lactose.
Assuntos
Clostridium , Escherichia coli , Lactose , Lactulose , Lactulose/metabolismo , Lactulose/biossíntese , Lactose/metabolismo , Clostridium/enzimologia , Clostridium/genética , Escherichia coli/genética , Escherichia coli/metabolismo , Proteínas de Bactérias/metabolismo , Proteínas de Bactérias/genética , Carboidratos Epimerases/genética , Carboidratos Epimerases/metabolismo , Concentração de Íons de Hidrogênio , Proteínas Recombinantes/metabolismo , Proteínas Recombinantes/genética , Celobiose/metabolismo , TemperaturaRESUMO
Unexpected cross-contamination by foreign components during the manufacturing and quality control of pharmaceutical products poses a serious threat to the stable supply of drugs and the safety of customers. In Japan, in 2020, a mix-up containing a sleeping drug went undetected by liquid chromatography during the final quality test because the test focused only on the main active pharmaceutical ingredient (API) and known impurities. In this study, we assessed the ability of a powder rheometer to analyze powder characteristics in detail to determine whether it can detect the influence of foreign APIs on powder flow. Aspirin, which was used as the host API, was combined with the guest APIs (acetaminophen from two manufacturers and albumin tannate) and subsequently subjected to shear and stability tests. The influence of known lubricants (magnesium stearate and leucine) on powder flow was also evaluated for standardized comparison. Using microscopic morphological analysis, the surface of the powder was observed to confirm physical interactions between the host and guest APIs. In most cases, the guest APIs were statistically detected due to characteristics such as their powder diameter, pre-milling, and cohesion properties. Furthermore, we evaluated the flowability of a formulation incorporating guest APIs for direct compression method along with additives such as microcrystalline cellulose, potato starch, and lactose. Even in the presence of several additives, the influence of the added guest APIs was successfully detected. In conclusion, powder rheometry is a promising method for ensuring stable product quality and reducing the risk of unforeseen cross-contamination by foreign APIs.
Assuntos
Contaminação de Medicamentos , Pós , Reologia , Pós/química , Reologia/métodos , Contaminação de Medicamentos/prevenção & controle , Excipientes/química , Acetaminofen/química , Celulose/química , Preparações Farmacêuticas/química , Controle de Qualidade , Aspirina/química , Química Farmacêutica/métodos , Lactose/química , Composição de Medicamentos/métodos , Lubrificantes/química , Princípios AtivosRESUMO
Approximately 30% of milk protein is ß-casein. We aimed to determine whether lactose maldigesters who chronically consumed two cups of A1/A2 milk (containing 75% A1 ß-casein and 25% A2 ß-casein) would adapt to have fewer intolerance symptoms, lower serum inflammatory markers, and/or altered glutathione levels similar to those consuming A2 milk (containing 100% A2 ß-casein). A double-blinded, randomized, crossover trial was conducted. Sixteen confirmed lactose maldigesters consumed 250 mL of A1/A2 milk and A2 milk twice daily with meals for two weeks. At the end of the adaptation period on day 15, lactose maldigestion was measured after a challenge with the same milk used for adaptation (0.5 g of lactose per kg of body weight) with a hydrogen breath test. Fecal urgency was higher during the two-week consumption of A1/A2 milk compared to A2 milk (p = 0.04, n = 16). Bloating (p = 0.03, n = 16) and flatulence (p = 0.02, n = 16) were also higher on the 15th day with A1/A2 milk compared to A2 milk challenge. However, day-to-day symptoms, hydrogen, serum inflammatory markers, and antioxidant concentrations were not different after A1/A2 and A2 milk consumption adaptation periods. Adaptation over two weeks did not improve lactose digestion or tolerance of A1/A2 milk to match that of A2 milk.
Assuntos
Caseínas , Estudos Cross-Over , Intolerância à Lactose , Leite , Humanos , Caseínas/administração & dosagem , Leite/química , Feminino , Método Duplo-Cego , Adulto , Animais , Masculino , Lactose , Pessoa de Meia-Idade , Biomarcadores/sangue , Flatulência/etiologia , Testes Respiratórios , Adaptação FisiológicaRESUMO
In individuals with hearing loss, protection of residual hearing is essential following cochlear implantation to facilitate acoustic and electric hearing. Hearing preservation requires slow insertion, atraumatic electrode and delivery of the optimal quantity of a pharmacological agent. Several studies have reported variable hearing outcomes with osmotic pump-mediated steroid delivery. New drugs, such as sialyllactose (SL) which have anti-inflammatory effect in many body parts, can prevent tissue overgrowth. In the present study, the positive effects of the pharmacological agent SL against insults were evaluated in vitro using HEI-OC1 cells. An animal model to simulate the damage due to electrode insertion during cochlear implantation was used. SL was delivered using osmotic pumps to prevent loss of the residual hearing in this animal model. Hearing deterioration, tissue fibrosis and ossification were confirmed in this animal model. Increased gene expressions of inflammatory cytokines were identified in the cochleae following dummy electrode insertion. Following the administration of SL, insertion led to a decrease in hearing threshold shifts, tissue reactions, and inflammatory markers. These results emphasize the possible role of SL in hearing preservation and improve our understanding of the mechanism underlying hearing loss after cochlear implantation.
Assuntos
Implante Coclear , Perda Auditiva , Lactose , Animais , Lactose/análogos & derivados , Lactose/farmacologia , Perda Auditiva/prevenção & controle , Perda Auditiva/tratamento farmacológico , Audição/efeitos dos fármacos , Cóclea/efeitos dos fármacos , Cóclea/metabolismo , Camundongos , Modelos Animais de Doenças , Linhagem Celular , Citocinas/metabolismo , Masculino , Ácidos SiálicosRESUMO
Listeria monocytogenes, a widespread food-borne pathogen, utilizes diverse growth substrates including mono- and di-saccharides via PEP-phosphotransferase (PTS) systems. We evaluated a collection of L. monocytogenes isolates of different origins for their ability to utilize lactose, a disaccharide composed of galactose and glucose and the main carbon source in milk and dairy products. Notably, the dairy-associated outbreak strain F2365 could not utilize lactose efficiently, conceivably due to a frameshift mutation (lacR887del) resulting in a truncated LacR. Transcriptional activator LacR is involved in the expression of two PTS systems, encoded by the lpo operon lmo1718-1720 in combination with lmo2708 and the lmo2683-2685 operon, and linked to lactose and/or cellobiose metabolism in L. monocytogenes. Via experimental evolution of the ancestral strain F2365, an evolved isolate F2365 EV was obtained which showed enhanced growth and metabolism of lactose. Using the lactose-positive model strain L. monocytogenes EGDe as a control, HPLC experiments showed that EGDe and F2365 EV could consume lactose and utilize the glucose moiety, while the galactose moiety was exported from the cells. Genome sequencing of F2365 EV found the original lacR887del mutation was still present but an additional point mutation lmo2766C415T had occurred, resulting in an amino acid substitution in the putative regulator Lmo2766. The lmo2766 gene is located next to operon lmo2761-2765 with putative PTS genes in the genome. Notably, comparative RNAseq analysis confirmed that the lmo2761-2765 operon was strongly upregulated in F2365 EV in the presence of lactose but not in EGDe and F2365. Conversely, the LacR-regulated lpo operon, lmo2708, and lmo2683-2685 operon were only upregulated in EGDe. Additional growth and HPLC experiments, using mutants constructed in lactose-positive L. monocytogenes EGDe, showed reduced growth of the EGDe lacR887del mutant with no utilization of lactose, while the double mutant EGDe lacR887dellmo2766C415T showed enhanced growth and lactose utilization. Hence, these results demonstrate that an amino acid substitution in the Lmo2766 regulator activates a previously silent lactose utilization pathway encoded by PTS operon lmo2761-2765, facilitating the growth and metabolism of L. monocytogenes with lactose as a substrate. This finding enhances our understanding of the metabolic capabilities and adaptability of L. monocytogenes, offering a broader view of the lactose utilization capacity of this pathogen.