14 research outputs found
Lego DNA assembling, a simple in vitro method for constructing DNA molecule
Digestion-ligation based and recombination based methods for constructing recombinant DNA are the basic techniques in molecular biology and thus built one of the foundations for the modern life sciences. Here we describe a new strategy that can radically simplify some of the same task. The lego DNA assembling, based on strand annealing, allows in vitro assembly of multi DNA fragments in one step with precise junctions and excludes the need for any enzyme. As a proof of concept, we rapidly constructed plasmids from 4, 6 and 8 fragments with very high efficiencies (100%). And we found this method a powerful tool for synthetic biology, constructing a partial isoprene biosynthesis pathway (consisting of four genes) in 2 days. We also assembled a customized expression vector to show its modularity
SAM-Med3D
Although the Segment Anything Model (SAM) has demonstrated impressive
performance in 2D natural image segmentation, its application to 3D volumetric
medical images reveals significant shortcomings, namely suboptimal performance
and unstable prediction, necessitating an excessive number of prompt points to
attain the desired outcomes. These issues can hardly be addressed by
fine-tuning SAM on medical data because the original 2D structure of SAM
neglects 3D spatial information. In this paper, we introduce SAM-Med3D, the
most comprehensive study to modify SAM for 3D medical images. Our approach is
characterized by its comprehensiveness in two primary aspects: firstly, by
comprehensively reformulating SAM to a thorough 3D architecture trained on a
comprehensively processed large-scale volumetric medical dataset; and secondly,
by providing a comprehensive evaluation of its performance. Specifically, we
train SAM-Med3D with over 131K 3D masks and 247 categories. Our SAM-Med3D
excels at capturing 3D spatial information, exhibiting competitive performance
with significantly fewer prompt points than the top-performing fine-tuned SAM
in the medical domain. We then evaluate its capabilities across 15 datasets and
analyze it from multiple perspectives, including anatomical structures,
modalities, targets, and generalization abilities. Our approach, compared with
SAM, showcases pronouncedly enhanced efficiency and broad segmentation
capabilities for 3D volumetric medical images. Our code is released at
https://github.com/uni-medical/SAM-Med3D
Enhancing Production of Bio-Isoprene Using Hybrid MVA Pathway and Isoprene Synthase in E. coli
The depleting petroleum reserve, increasingly severe energy crisis, and global climate change are reigniting enthusiasm for seeking sustainable technologies to replace petroleum as a source of fuel and chemicals. In this paper, the efficiency of the MVA pathway on isoprene production has been improved as follows: firstly, in order to increase MVA production, the source of the “upper pathway” which contains HMG-CoA synthase, acetyl-CoA acetyltransferase and HMG-CoA reductase to covert acetyl-CoA into MVA has been changed from Saccharomyces cerevisiae to Enterococcus faecalis; secondly, to further enhance the production of MVA and isoprene, a alanine 110 of the mvaS gene has been mutated to a glycine. The final genetic strain YJM25 containing the optimized MVA pathway and isoprene synthase from Populus alba can accumulate isoprene up to 6.3 g/L after 40 h of fed-batch cultivation
Comparison of isoprene production from different recombinant strains.
<p>The experiment was conducted under flask conditions in triplicate.</p
Strains, plasmids and Oligonucleotide primers used in this study.
<p>Strains, plasmids and Oligonucleotide primers used in this study.</p
MVA production by strains with or without mutation of <i>mvaS</i> gene.
<p>The MVA isolated from cultural broth as described in “MVA quantification by gas chromatography (GC)”. The experiment was performed in triplicate.</p
The time course of isoprene production by YJM25.
<p>Isoprene accumulation (▪) and cell growth (Δ) in YJM25, Induction was carried out at an OD<sub>600</sub> of 12. Other experiment conditions were described in ‘Fed-batch fermentation’.</p