Probing the breadth of macrolide glycosyltransferases: in vitro remodeling of a polyketide antibiotic creates active bacterial uptake and enhances potency

The glycan portion of macrolide antibiotics modulates their efficacy. High-level expression of three macrolide GTs and kinetic analysis has revealed a highly selective synthetic "tool kit" with such plasticity that 12 glycan-modified macrolide antibiotics have been readily created. One of these (1-Gal) is enhanced over its parent oleandomycin (1) by "glycotargeting", allowing higher uptake through active internalization by virtue of the attachment of a glycan (Gal) not normally found on 1. Subsequent release of the targeting glycan by endogenous galactosidase activity releases 1.     

Adjustably Bioresorbable Sol-Gel Derived SiO<Subscript>2</Subscript> Matrices for Release of Large Biologically Active Molecules

Amorphous, sol-gel derived SiO₂ are known to biocompatible and bioresorbable materials. Bioresorbable materials have potential applications as implants or injectable matrices in the controlled delivery of biologically active agents in the living tissue. Bioresorbable matrices provide desirable properties, e.g., extra removal operations that have to be done with biostable matrices are avoided and the release of large therapeutic molecules can be controlled by matrix degradation rather than by diffusion. New important groups of drugs, such as biotechnically-produced peptides and proteins, are potential to be encapsulated in bioresorbable SiO₂, because they are typically larger in size and their direct oral administration without protecting matrix is difficult due to digestion. The methods to achieve a wide range of SiO₂ bioresorption rates (from days to months) are introduced in this study. This is done by a “conventional” alkoxy-based sol-gel method at protein-friendly conditions by adjusting the precursor ratios, aging of the sol and by using different preparation methods (casting, spray-drying and freeze-drying). The prepared morphologies include implantable monolithic sticks and injectable microspheres. The importance of chemical structure is shown in comparison with the specific surface area and pore volume.     

Vibronisches Spektralverhalten von Molekülen, 10. Mitt. Theoretische Molekülgeometrien und Spektrumstruktur der S0-S1-Absorption und Fluoreszenz des 2,5-Diphenylfurans

Summary Completely-optimized S₀ and S₁ molecular geometries of 2,5-diphenylfurane and the theoretical vibronic line spectra for its absorption and fluorescence are presented. The experimental spectroscopic peaks are reasonably reproduced by the calculated vibronic transitions.

     

Quasimartingales on partially ordered sets

The concept of a quasimartingale, and therefore also of a function of bounded variation, is extended to processes with a regular partially ordered index set V and with values in a Banach space. We show that quasimartingales can be described by their associated measures, defined on an inverse limit space $\text{S × Ω}$ containing $\text{V × Ω}$, furnished with the σ-algebra $\text{P}$ of the predictable sets. With the help of this measure, a Rao-Krickeberg and a Riesz decomposition is obtained, as well as a convergence theorem for quasimartingales. For a regular quasimartingale X it is proven that the spaces ($\text{S × Ω}$, $\text{P}$) and the measures associated with X are unique up to isomorphisms. In the case V = $\text{R}$₊ⁿ we prove a duality between classical (right-) quasimartingales and left-quasimartingales.     

Classical probability and the quantum mechanical trace formulation for expectations

The trace formulation of quantum mechanical expectations is derived in a classical deterministic setting by averaging over an assembly of states. Interference of probabilities is discussed and its usual Hilbert space formulation is questioned. Nevertheless, it is shown that the observable predictions of quantum statics remain unchanged in the framework developed here.     

On the possible existence of stable four-quark scalar mesons with charm and strangeness

We observe that the existence of the S¹ and δ just below K$\text{K}$ threshold has a natural interpretation in the four-quark model for these states, and we apply this interpretation to predict the possible existence of stable four-quark scalar mesons with charm and strangeness.