Consolidated bioprocessing for cellulosic ethanol conversion by cellulase-xylanase cell-surfaced yeast consortium.

Consolidated bioprocessing (CBP) strategy was developed to construct a cell-surface displayed consortium for heterologously expressing functional lignocellulytic enzymes. The reaction system composed of two engineered yeast strains: Y5/XynII-XylA (co-displaying two types of xylanases) and Y5/EG-CBH-BGL (co-displaying three types of cellulases). The immobilization of recombinant fusion proteins and their cell-surface accessibility of were analyzed by flow cytometry and immunofluorescence. The feasibility of consolidated bioprocessing by using pretreated corn stover (CS) as substrate for direct bioconversion was further investigated, and the synergistic activity and proximity effect between cellulases and xylanases on lignocelluloses degradation were also discussed in this work. Without any commercial enzyme addition, the combined yeast consortium produced 1.61 g/L ethanol which achieved 64.7% of the theoretical ethanol yield during 144 h from steam-exploded CS. The results indicated that the assembly of cellulases and xylanases using a synthetic consortium capable of combined displaying lignocellulytic enzymes is a promising approach for simultaneous saccharification and fermentation to ethanol from lignocellulosic biomass.

[Clinical observation of placement of tympanostomy microtube to treat middle ear atelectasis].

OBJECTIVE: To investigate the treatment efficacy of tympanostomy microtube placement surgery for middle ear atelectasis. METHODS: A retrospective analysis was conducted on 26 patients (28 ears) with middle ear atelectasis, who complained fullness or pressure in the ears.Otoscope showed tympanic membrane invagination, scattered or disappeared cone of light, tympanic membrane was pale and dull. The pure tone audiometry air-bone gap >10 dB. Acoustic immittance showed tympanic negative pressure. All the ears had atelectasis of I-III grade. Patients were performed tympanic membrane microtube placement under local anesthesia, and were followed up for 6-12 months. RESULTS: Twenty-five ears recovered from the fullness after operation, in which, 23 ears reverted from type "C" to type "A" in acoustic immittance tests and the pure-tone average (PTA) of hearing thresholds were decreasing from 5 to 20 dB, while 2 ears relapse after removal of the microtube. Three ears with middle ear atelectasis of III grade were ineffectiveness. All the 26 cases had no complications including middle ear infection, tympanosclerosis, and permanent perforation after removal of the microtubes. CONCLUSIONS: The placement of tympanostomy microtube can be used to treat middle ear atelectasis, especially to the patients with middle ear atelectasis of I-II grade as it is effective on elimination of middle ear negative pressure and remission of fullness.

Sustained and cancer cell targeted cytosolic delivery of Onconase results in potent antitumor effects.

The unfavorable pharmacokinetics and low tumor specificity hampered the potential clinical utility of Onconase, a promising modality in anticancer treatment with unique targets and novel mechanism of action. In this study, a modular and multi-stage drug delivery system (DDS) that can break down organ (renal accumulation), cellular (cancer cell specific uptake) and sub-cellular (endosomal escape) level barriers encountered by Onconase during its long journey from injection site to the cytoplasm of cancer cell was designed. Human serum albumin fusion extended the half-life of Onconase and significantly decreased its kidney accumulation. Epithelial cell adhesion molecular (EpCAM) specific antibody fragment appending enhanced binding and internalization of Onconase toward EpCAM positive cancer cell and increased its tumor accumulation and retention. Tethering Onconase to its carrier by cleavable disulfide linker prompted endosomal escape and restored its cytotoxicity. In vivo antitumor efficacy assay in human tumor xenograft model revealed that only when the entire organ, cellular and sub-cellular level barriers had been broken down, will Onconase turn into a potent antitumor agent.

Balancing the pharmacokinetics and pharmacodynamics of interferon-α2b and human serum albumin fusion protein by proteolytic or reductive cleavage increases its in vivo therapeutic efficacy.

Human serum albumin (HSA) fusion (Albufusion) technology has evolved to be a general strategy to increase the in vivo half-lives of therapeutic proteins. However, because of the steric hindrance effect of HSA, conventional Albufusion technology improves the pharmacokinetics (PK) at the cost of pharmacodynamics (PD). To achieve balanced PK and PD of interferon-α2b (IFN-α2b) and HSA fusion protein, protease cleavage sites or disulfide linkage that enabled releasing of intact IFN-α2b with full activity was introduced between these two moieties. Nonreleasable and releasable fusion proteins showed similar cell surface receptor binding affinities; however, releasable fusion proteins exhibited release efficiency proportional increase of in vitro antiviral and antiproliferative activities. The release rate also had a profound impact on the in vivo pharmaceutical properties of fusion proteins. Releasable fusion proteins with intermediate release rate had the most balanced PK and PD, which translated into improved therapeutic efficacy in the HT29 human colon cancer xenograft model. Releasable Albufusion (rAlbufusion) allows tailored design of the PK/PD profile and greatly extends the utility of conventional Albufusion technology.