Search results for "Lactase"
showing 10 items of 13 documents
Development of enzymatically-active bacterial cellulose membranes through stable immobilization of an engineered beta-galactosidase
2018
Enzymatically-active bacterial cellulose (BC) was prepared by non-covalent immobilization of a hybrid enzyme composed by a β-galactosidase from Thermotoga maritima (TmLac) and a carbohydrate binding module (CBM2) from Pyrococcus furiosus. TmLac-CBM2 protein was bound to BC, with higher affinity at pH 6.5 than at pH 8.5 and with high specificity compared to the non-engineered enzyme. Both hydrated (HBC) and freeze-dried (DBC) bacterial cellulose showed equivalent enzyme binding efficiencies. Initial reaction rate of HBC-bound enzyme was higher than DBC-bound and both of them were lower than the free enzyme. However, enzyme performance was similar in all three cases for the hydrolysis of 5% l…
The evolution of lactase persistence in Europe. A synthesis of archaeological and genetic evidence
2012
Lactase persistence, the ability to digest the milk sugar lactose in adulthood, is highly associated with a T allele situated 13,910 bp upstream from the actual lactase gene in Europeans. The frequency of this allele rose rapidly in Europe after transition from hunter–gatherer to agriculturalist lifestyles and the introduction of milkable domestic species from Anatolia some 8000 years ago. Here we first introduce the archaeological and historic background of early farming life in Europe, then summarize what is known of the physiological and genetic mechanisms of lactase persistence. Finally, we compile the evidence for a co-evolutionary process between dairying culture and lactase persisten…
Evolution of lactase persistence: an example of human niche construction
2011
Niche construction is the process by which organisms construct important components of their local environment in ways that introduce novel selection pressures. Lactase persistence is one of the clearest examples of niche construction in humans. Lactase is the enzyme responsible for the digestion of the milk sugar lactose and its production decreases after the weaning phase in most mammals, including most humans. Some humans, however, continue to produce lactase throughout adulthood, a trait known as lactase persistence. In European populations, a single mutation (−13910*T) explains the distribution of the phenotype, whereas several mutations are associated with it in Africa and the Middle …
Low Prevalence of Lactase Persistence in Bronze Age Europe Indicates Ongoing Strong Selection over the Last 3,000 Years
2020
Lactase persistence (LP), the continued expression of lactase into adulthood, is the most strongly selected single gene trait over the last 10,000 years inmultiple human populations. It has been posited that the primary allele causing LP among Eurasians, rs4988235-A [1], only rose to appreciable frequencies during the Bronze and Iron Ages [2, 3], long after humans started consuming milk from domesticated animals. This rapid rise has been attributed to an influx of people from the Pontic-Caspian steppe that began around 5,000 years ago [4, 5]. We investigate the spatiotemporal spread of LP through an analysis of 14 warriors from the Tollense Bronze Age battlefield in northern Germany ( 3,20…
The genomic history of the Aegean palatial civilizations
2021
Summary The Cycladic, the Minoan, and the Helladic (Mycenaean) cultures define the Bronze Age (BA) of Greece. Urbanism, complex social structures, craft and agricultural specialization, and the earliest forms of writing characterize this iconic period. We sequenced six Early to Middle BA whole genomes, along with 11 mitochondrial genomes, sampled from the three BA cultures of the Aegean Sea. The Early BA (EBA) genomes are homogeneous and derive most of their ancestry from Neolithic Aegeans, contrary to earlier hypotheses that the Neolithic-EBA cultural transition was due to massive population turnover. EBA Aegeans were shaped by relatively small-scale migration from East of the Aegean, as e…
The Origins of Lactase Persistence in Europe
2009
Lactase persistence (LP) is common among people of European ancestry, but with the exception of some African, Middle Eastern and southern Asian groups, is rare or absent elsewhere in the world. Lactase gene haplotype conservation around a polymorphism strongly associated with LP in Europeans (−13,910 C/T) indicates that the derived allele is recent in origin and has been subject to strong positive selection. Furthermore, ancient DNA work has shown that the −13,910*T (derived) allele was very rare or absent in early Neolithic central Europeans. It is unlikely that LP would provide a selective advantage without a supply of fresh milk, and this has lead to a gene-culture coevolutionary model w…
Lactase persistence and milk consumption in Europe: an interdisciplinary approach involving genetics and archeology:
2013
The ability to digest milk during adulthood (lactase persistence) is a genetically determined trait present only in humans. Its origin and diffusion are correlated with the development of pastoralism and the consumption of fresh milk. This work will present the genetic and archaeologi- cal data that allow the reconstruction of the co-evolutionary process between dairying culture and lactase persistence, as well as a discussion of the chronology and the way lactase persistence spread in Europe. Sposobnost presnavljanja mleka v odrasli dobi (laktazna persistenca) je genetsko pogojena značilnost, navzoča le pri ljudeh. Njen izvor in razširitev sta povezana z razvojem pastirstva in uživanjem sv…
Revalorization of cellulosic wastes from Posidonia oceanica and Arundo donax as catalytic materials based on affinity immobilization of an engineered…
2020
Catalytic materials obtained by enzyme immobilization have multiple potential applications in the food industry. The choice of the immobilization method and support may be critical to define the properties of the immobilized enzyme compared to the soluble form. Although the use of immobilized enzymes shows multiple advantages, their catalytic efficiency is compromised in many instances. Molecular engineering techniques have been used to generate hybrid proteins where the enzyme of interest is fused to a module with affinity to a specific biopolymer. Binding of the hybrid TmLac-CBM2 protein, in which the β-galactosidase from Thermotoga maritima is fused to a carbohydrate-binding module from …
Association of the rs4988235 in the lactase gene with obesity and its modulation by dairy products in a Mediterranean population
2011
The -13910C>T polymorphism (rs4988235) upstream from the lactase (LCT) gene, strongly associated with lactase persistence (LP) in Europeans, is emerging as a new candidate for obesity. We aimed to analyze the association of this polymorphism with obesity-related variables and its modulation by dairy product intake in an elderly population. We studied 940 high-cardiovascular risk Spanish subjects (aged 67 ± 7 years). Dairy product consumption was assessed by a validated questionnaire. Anthropometric variables were directly measured, and metabolic syndrome-related variables were obtained. Prevalence of genotypes was: 38.0% CC (lactase nonpersistent (LNP)), 45.7% CT, and 16.3% TT. The CC genot…
Associations of the MCM6-rs3754686 proxy for milk intake in Mediterranean and American populations with cardiovascular biomarkers, disease and mortal…
2016
Controversy persists on the association between dairy products, especially milk, and cardiovascular diseases (CVD). Genetic proxies may improve dairy intake estimations, and clarify diet-disease relationships through Mendelian randomization. We meta-analytically (n T (nonpersistence>persistence), dairy intake, and CVD biomarkers in American (Hispanics, African-American and Whites) and Mediterranean populations. Moreover, we analyzed longitudinal associations with milk, CVD and mortality in PREDIMED), a randomized Mediterranean diet (MedDiet) intervention trial (n = 7185). The MCM6-rs3754686/MCM6-rs309180 (as proxy), LP-allele (T) was strongly associated with higher milk intake, but inconsis…