Functionalized calcium carbonate microparticles for the delivery of proteins.

The recently introduced functionalized calcium carbonate (FCC), a porous microparticle with a nano-structured, lamellar surface, shows promising properties in the field of oral drug delivery. In this work, FCC was loaded with biomolecules e.g. lysozyme (Lys) and bovine serum albumin (BSA) in order to investigate its suitability to deliver protein based drugs. Loading efficiency for our model proteins was >90% and enzyme activity was preserved as demonstrated by Michaelis-Menten enzyme kinetic experiments. Circular dichroism analysis confirmed, that neither the structure of both model substances, nor the activity of Lys was affected by the loading process or the interaction with the surface of FCC. Electron microscopy (SEM) and mercury porosimetry were indicative of protein deposition on the particle surface as well as within the particle pores. Release properties were investigated in a customized flow cell, which simulates the conditions in the oral cavity. Depending on the isoelectric point of the investigated proteins, complete release was obtained within 1.5h. This work shows, that FCC is a suitable pharmaceutical excipient for delivery of proteins.

Microbial population dynamics in the faeces of wood-eating loricariid catfishes.

UNLABELLED: Catfishes of the genus Panaque are known for their ability to feed on wood and hence to process cellulose fibres in their digestive systems. The paper industry uses cellulose fibres and thus has an interest in exploiting this property biomimetically: it could be employed as a pretreatment to lessen the energy required by the mechanical production stage of manufacturing nanocellulose fibres. Here, we characterize the diet-associated in situ microbial diversity and population dynamic in the faeces of catfish (Panaque sp.) exposed to consecutive diets of pellet food and then wood. Fish faeces samples were collected and investigated by parallel DNA deep amplicon sequencing of the bacterial 16S rRNA SSU for both diet conditions. The most frequently occurring bacterium in the faeces was Cetobacterium sp. The dominant cellulolytic bacterial genera found in ascending relative abundance were as follows: Aeromonas sp., Flavobacterium sp., Bacteroides sp., Pseudomonas sp. and Cellvibrio sp. Diet-associated changes in the faeces microbiome were noted for Flavobacterium sp. Extensive microbial diversity was found in catfish faeces, evidenced using culture-independent molecular techniques. No significant diet-associated effects on the microbiome in terms of biodiversity were observed in the catfish faeces, but diet-associated changes in the microbial population structure were observed. SIGNIFICANCE AND IMPACT OF THE STUDY: Although catfishes are not classified as true xylivores, inhabiting their faeces are bacteria that may provide a novel source of cellulolytic enzyme. Based on this first microbiology study, the faeces and thus the gastrointestinal microbiome of Panaque catfishes are an unexplored reservoir of microbial extracts with enhanced polysaccharide transforming enzyme activity. The biomimetical exploitation of this cellulolytic activity in the form of novel enzymes or by applying a mixture of cellulolytic micro-organisms could accomplish a pretreatment to the mechanical production process of nanocellulose fibres, thus could reduce the energy consumption costs significantly.

Measurement and Network Modeling of Liquid Permeation into Compacted Mineral Blocks.

A microbalance has been used to measure the rate of uptake of a wetting fluid, 1,3-propandiol, into a cube of compacted calcium carbonate. The cube had sides 12 mm long, with a wax band applied to the outer perpendicular edges of one basal plane to prevent external surface uptake, and the liquid was applied in a highly controlled manner at this single face only. The percolation characteristics of an identical sample were measured by mercury porosimetry. A three-dimensional void structure was generated with the same percolation characteristics using a software package called "Pore-Cor." The wetting of 1,3-propandiol into this model structure was then calculated using an extended Lucas-Washburn equation, developed by Bosanquet, which includes viscous, inertial, and capillary force effects. Neither the experimental nor the simulated wetting can be explained in terms of an "hydraulic stream tube" or "effective hydraulic radius" model. A mathematical function is presented which compensates for the differences in the boundary conditions between the simulation and the experiment. The wetting is found to be initially slowed by inertial flow, then speeded up to a t(0.8) dependence by the connectivity of the three-dimensional void network. The effect of the inertial flow is most pronounced for larger pores. Copyright 2000 Academic Press.

Ethnic intermarriage and its consequences for cystic fibrosis carrier screening.

Cystic fibrosis gene mutations can vary in frequency between different ethnic populations. However, there is a rising trend of ethnic intermarriage in the United States, a situation suggesting that differences in specific mutation frequencies currently apparent in Europe may not persist for long in this country. Therefore, limited mutation screens targeted at specific ethnic groups and risk calculations based on data from more homogeneous European populations may not be appropriate in the United States. The genetic consequences of ethnic admixture are also likely to extend to other recessive diseases (e.g., Tay-Sachs, thalassemia), which, in the past, have been limited largely to particular ethnic, racial, or religious subgroups, with implications for public health agencies overseeing newborn screening programs for genetic diseases and for clinical genetics programs offering population-based carrier-detection programs, carrier risk assessment, and counseling.