Genome sequence of the Lotus corniculatus microsymbiont Mesorhizobium loti strain R88B

Mesorhizobium loti strain R88B was isolated in 1993 in the Rocklands range in Otago, New Zealand from a Lotus corniculatus root nodule. R88B is an aerobic, Gram-negative, non-spore-forming rod. This report reveals the genome of M. loti strain R88B contains a single scaffold of size 7,195,110 bp which encodes 6,950 protein-coding genes and 66 RNA-only encoding genes. This genome does not harbor any plasmids but contains the integrative and conjugative element ICEMlSym(R7A), also known as the R7A symbiosis island, acquired by horizontal gene transfer in the field environment from M. loti strain R7A. It also contains a mobilizable genetic element ICEMladh(R88B), that encodes a likely adhesin gene which has integrated downstream of ICEMlSym(R7A), and three acquired loci that together allow the utilization of the siderophore ferrichrome. This rhizobial genome is one of 100 sequenced as part of the DOE Joint Genome Institute 2010 Genomic Encyclopedia for Bacteria and Archaea-Root Nodule Bacteria (GEBA-RNB) project.

Genome sequence of the Lotus spp. microsymbiont Mesorhizobium loti strain NZP2037

Mesorhizobium loti strain NZP2037 was isolated in 1961 in Palmerston North, New Zealand from a Lotus divaricatus root nodule. Compared to most other M. loti strains, it has a broad host range and is one of very few M. loti strains able to form effective nodules on the agriculturally important legume Lotus pedunculatus. NZP2037 is an aerobic, Gram negative, non-spore-forming rod. This report reveals that the genome of M. loti strain NZP2037 does not harbor any plasmids and contains a single scaffold of size 7,462,792 bp which encodes 7,318 protein-coding genes and 70 RNA-only encoding genes. This rhizobial genome is one of 100 sequenced as part of the DOE Joint Genome Institute 2010 Genomic Encyclopedia for Bacteria and Archaea-Root Nodule Bacteria (GEBA-RNB) project.

Genome sequence of the Lotus spp. microsymbiont Mesorhizobium loti strain R7A

Mesorhizobium loti strain R7A was isolated in 1993 in Lammermoor, Otago, New Zealand from a Lotus corniculatus root nodule and is a reisolate of the inoculant strain ICMP3153 (NZP2238) used at the site. R7A is an aerobic, Gram-negative, non-spore-forming rod. The symbiotic genes in the strain are carried on a 502-kb integrative and conjugative element known as the symbiosis island or ICEMlSym(R7A). M. loti is the microsymbiont of the model legume Lotus japonicus and strain R7A has been used extensively in studies of the plant-microbe interaction. This report reveals that the genome of M. loti strain R7A does not harbor any plasmids and contains a single scaffold of size 6,529,530 bp which encodes 6,323 protein-coding genes and 75 RNA-only encoding genes. This rhizobial genome is one of 100 sequenced as part of the DOE Joint Genome Institute 2010 Genomic Encyclopedia for Bacteria and Archaea-Root Nodule Bacteria (GEBA-RNB) project.

Expansion of human hematopoietic stem/progenitor cells on decellularized matrix scaffolds

Umbilical cord blood (UCB) is one of the richest sources for hematopoietic stem/progenitor cells (HSPCs), with more than 3000 transplantations performed each year for the treatment of leukemia and other bone marrow, immunological, and hereditary diseases. However, transplantation of single cord blood units is mostly restricted to children, due to the limited number of HSPC per unit. This unit develops a method to increase the number of HSPCs in laboratory conditions by using cell-free matrices from bone marrow cells that mimic 'human-body niche-like' conditions as biological scaffolds to support the ex vivo expansion of HSPCs. In this unit, we describe protocols for the isolation and characterization of HSPCs from UCB and their serum-free expansion on decellularized matrices. This method may also help to provide understanding of the biochemical organization of hematopoietic niches and lead to suggestions regarding the design of tissue engineering-based biomimetic scaffolds for HSPC expansion for clinical applications.

Modular synthesis of linear Bis- and Tris-monodentate fused [6]Polynorbornane-Based Ligands and their assembly into coordination cages

A modular approach has been developed for the synthesis of rigid linear di- and tritopic ligands based on a fused [6]polynorbornane scaffold. The design provides up to three sites for installing functionality, including both "ends" and a "central" position with the advantage that each region can be independently addressed during synthesis. To illustrate the utility of the approach, both pyridyl and picolyl units were incorporated to provide six new ligands, with centers and ends either matched or mismatched. Indeed, both [M2 L4 ] cages with endohedral functionality and [M3 L4 ] complexes were cleanly produced from these ligands with assembled structures confirmed by using (1) H NMR spectroscopy, HRMS, and molecular modelling.

Tuning the mechanical and morphological properties of self-assembled peptide hydrogels via control over the gelation mechanism through regulation of ionic strength and the rate of pH change

Hydrogels formed by the self-assembly of peptides are promising biomaterials. The bioactive and biocompatible molecule Fmoc-FRGDF has been shown to be an efficient hydrogelator via a π-β self-assembly mechanism. Herein, we show that the mechanical properties and morphology of Fmoc-FRGDF hydrogels can be effectively and easily manipulated by tuning both the final ionic strength and the rate of pH change. The increase of ionic strength, and consequent increase in rate of gelation and stiffness, does not interfere with the underlying π-β assembly of this Fmoc-protected peptide. However, by tuning the changing rate of the system's pH through the use of glucono-δ-lactone to form a hydrogel, as opposed to the previously reported HCl methodology, the morphology (nano- and microscale) of the scaffold can be manipulated.