Recent advances on prebiotic lactulose production

Lactulose, a synthetic disaccharide, has received increasing interest due to its role as a prebiotic. The production of lactulose is important in the dairy industry, as it is regarded as a high value-added derivative of whey or lactose. The industrial production of lactulose is still mainly done by chemical isomerization. Due to concerns on the environmental and tedious separation processes, the enzymatic-based lactulose synthesis has been regarded as an interesting alternative. This work aims at comparing chemical and enzyme-catalyzed lactulose synthesis. With an emphasis on the latter one, this review discusses the influences of the critical operating conditions and the suited operation mode on the transgalactosylation of lactulose using microbial enzymes. As an update and supplement to other previous reviews, this work also summarizes the recent reports that highlighted the enzymatic isomerization of lactose using cellobiose 2-epimerase to produce lactulose at elevated yields.     

Size-dependent predation risk in cryptic prey

Journal of Ethology - Visual crypsis of prey is determined by the interaction between an individual’s physical appearance to their predators and visual aspects of their environment. Physical...     

Population diversity of yeasts and lactic acid bacteria in pig feed fermented with whey, wet wheat distillers' grains, or water at different temperatures

The diversity of populations of yeast and lactic acid bacteria (LAB) in pig feeds fermented at 10, 15, or 20 degrees C was characterized by rRNA gene sequencing of isolates. The feeds consisted of a cereal grain mix blended with wet wheat distillers' grains (WWDG feed), whey (W feed), or tap water (WAT feed). Fermentation proceeded for 5 days without disturbance, followed by 14 days of daily simulated feed outtakes, in which 80% of the contents were replaced with fresh feed mixtures. In WWDG feed, Pichia galeiformis became the dominant yeast species, independent of the fermentation temperature and feed change. The LAB population was dominated by Pediococcus pentosaceus at the start of the fermentation period. After 3 days, the Lactobacillus plantarum population started to increase in feeds at all temperatures. The diversity of LAB increased after the addition of fresh feed components. In W feed, Kluyveromyces marxianus dominated, but after the feed change, the population diversity increased. With increasing fermentation temperatures, there was a shift toward Pichia membranifaciens as the dominant species. L. plantarum was the most prevalent LAB in W feed. The WAT feed had a diverse microbial flora, and the yeast population changed throughout the whole fermentation period. Pichia anomala was the most prevalent yeast species, with increasing occurrence at higher fermentation temperatures. Pediococcus pentosaceus was the most prevalent LAB, but after the feed change, L. plantarum started to proliferate. The present study demonstrates that the species composition in fermented pig feed may vary considerably, even if viable cell counts indicate stable microbial populations.     

Osteoactivin is a novel osteoclastic protein and plays a key role in osteoclast differentiation and activity

This study presents gene expression, protein expression, and in situ immunohistochemical evidence that osteoclasts express high levels of osteoactivin (OA), which had previously been reported to be an osteoblast-specific protein in bone. OA expression in osteoclasts was up-regulated upon receptor activator of NFkappaB ligand-induced differentiation. Suppression of functional activity of OA with neutralizing antibody reduced cell size, number of nuclei, fusion, and bone resorption activity of osteoclasts. OA was co-immunoprecipitated with integrin beta3 and beta1, indicating that OA co-localizes with integrin beta3 and/or beta1 in a hetero-polymeric complex in osteoclasts. These findings indicate that OA is a novel osteoclastic protein and plays a role in osteoclast differentiation and/or activity.     

Optimisation of pharmacokinetic properties to afford an orally bioavailable and selective V1A receptor antagonist

The previously described lead compound 5 is a potent and selective V_1A antagonist with affinity at both the rat and human receptor, but displays poor oral bioavailability and moderate clearance. We report herein the successful optimisation of the pharmacokinetic (PK) properties to afford the potent, selective, orally bioavailable and CNS penetrant compound 15f. A custom optimisation approach was required which demonstrated the value of using early, rapid in vivo PK studies to show improvements in oral exposure. Such assays may be of particular value where low oral bioavailability is anticipated to be multifactorial (e.g., permeability, gut wall metabolism and/or transport) where satisfactory modelling of in vitro data is likely to be difficult within a drug discovery context.