Leptomeningeal metastases (LM) are more frequent in non-small-cell lung cancer (NSCLC) with epidermal growth factor receptor (EGFR) mutations. Due to limited access to leptomeningeal lesions, the ...purpose of this study was to explore the potential role of cerebrospinal fluid (CSF) as a source of liquid biopsy in patients with LM.
Primary tumor, CSF, and plasma in NSCLC with LM were tested by next-generation sequencing. In total, 45 patients with suspected LM underwent lumbar puncture, and those with EGFR mutations diagnosed with LM were enrolled.
A total of 28 patients were enrolled in this cohort; CSF and plasma were available in 26 patients, respectively. Driver genes were detected in 100% (26/26), 84.6% (22/26), and 73.1% (19/26) of samples comprising CSF cell-free DNA (cfDNA), CSF precipitates, and plasma, respectively; 92.3% (24/26) of patients had much higher allele fractions in CSF cfDNA than the other two media. Unique genetic profiles were captured in CSF cfDNA compared with those in plasma and primary tissue. Multiple copy number variations (CNVs) were mainly identified in CSF cfDNA, and MET copy number gain identified in 47.8% (11/23) of patients was the most frequent one, while other CNVs included ERBB2, KRAS, ALK, and MYC. Moreover, loss of heterozygosity (LOH) of TP53 was identified in 73.1% (19/26) CSF cfDNA, which was much higher than that in plasma (2/26, 7.7%; P<0.001). There was a trend towards a higher frequency of concomitant resistance mutations in patients with TP53 LOH than those without (70.6% versus 33.3%; P=0.162). EGFR T790M was identified in CSF cfDNA of 30.4% (7/23) of patients who experienced TKI progression.
CSF cfDNA could reveal the unique genetic profiles of LM and should be considered as the most representative liquid biopsy medium for LM in EGFR-mutant NSCLC.
Aims
We aimed to explore Yarrowia lipolytica carbonyl reductases as effective biocatalysts and to develop efficient asymmetric reduction systems for chiral alcohol synthesis.
Methods and Results
...Yarrowia lipolytica carbonyl reductase genes were obtained via homologous sequence amplification strategy. Two carbonyl reductases, YaCRI and YaCRII, were identified and characterized, and used to catalyse the conversion of 2‐hydroxyacetophenone (2‐HAP) to optically pure (S)‐1‐phenyl‐1,2‐ethanediol. Enzymatic assays revealed that YaCRI and YaCRII exhibited specific activities of 6·96 U mg−1 (99·8% e.e.) and 7·85 U mg−1 (99·9% e.e.), respectively, and showed moderate heat resistance at 40–50°C and acid tolerance at pH 5·0–6·0. An efficient whole‐cell two‐phase system was established using reductase‐expressing recombinant Escherichia coli. The conversion of 2‐HAP (20·0 g l−1) conversion with the solvent of dibutyl phthalate was approximately 70‐fold higher than in water. Furthermore, the two recombinant E. coli displayed biocatalyst activity and enantioselectivity towards several different carbonyl compounds, and E. coli BL21 (DE3)/pET‐28a‐yacrII showed a broad substrate spectrum.
Conclusions
A new whole‐cell recombinant E. coli‐based bioreduction system for enantiopure alcohol synthesis with high enantioselectivity at high substrate concentrations was developed.
Significance and Impact of the Study
We proposed a promising approach for the efficient preparation of enantiopure chiral alcohols.
Both inflammatory processes and glutamatergic systems have been implicated in the pathophysiology of mood-related disorders. However, the role of caspase-1, a classic inflammatory caspase, in ...behavioral responses to chronic stress remains largely unknown. To address this issue, we examined the effects and underlying mechanisms of caspase-1 on preclinical murine models of depression. We found that loss of caspase-1 expression in Caspase-1
knockout mice alleviated chronic stress-induced depression-like behaviors, whereas overexpression of caspase-1 in the hippocampus of wild-type (WT) mice was sufficient to induce depression- and anxiety-like behaviors. Furthermore, chronic stress reduced glutamatergic neurotransmission and decreased surface expression of glutamate receptors in hippocampal pyramidal neurons of WT mice, but not Caspase-1
mice. Importantly, pharmacological inhibition of caspase-1-interleukin-1β (IL-1β) signaling pathway prevented the depression-like behaviors and the decrease in surface expression of α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors (AMPARs) in stressed WT mice. Finally, the effects of chronic stress on both depression- and anxiety-like behaviors can be mimicked by exogenous intracerebroventricular (i.c.v.) administration of IL-1β in both WT and Caspase-1
mice. Taken together, our findings demonstrate that an increase in the caspase-1/IL-1β axis facilitates AMPAR internalization in the hippocampus, which dysregulates glutamatergic synaptic transmission, eventually resulting in depression-like behaviors. These results may represent an endophenotype for chronic stress-induced depression.
Trans‐4‐Hydroxy‐l‐proline (trans‐Hyp) is a valuable chiral building block for the synthesis of pharmaceutical intermediates. Bioconversion of l‐proline using recombinant strain with ...proline‐4‐hydroxylase (P4H) is a preferred biocatalytic process in the economical production of trans‐Hyp. In this study, a recombinant E. coli overexpressing hydroxylase (P4H), γ‐glutamyl kinase and glutamate‐semialdehyde dehydrogenase (ProBA) genes were constructed by knocking out the key genes in the metabolism. These key genes contained putA encoding proline dehydrogenase (PutA) in the l‐proline metabolism and other catalytic enzyme genes, sucAB encoding α‐ketoglutarate dehydrogenase (SucAB), aceAK encoding isocitratelyase (AceA) and isocitrate dehydrogenase kinase/phosphatase (AceK) in the TCA cycle. This recombinant strain coupled the synthetic pathway of trans‐Hyp with TCA cycle of the host strain. It inhibited the consumption of l‐proline completely and promoted the accumulation of 2‐oxoglutarate (2‐OG) as a co‐substrate, which realized the highest conversion of glucose to trans‐Hyp. A fed‐batch strategy was designed, capable of producing 31·0 g l−1 trans‐Hyp from glucose. It provided a theoretical basis for commercial conversion of glucose to trans‐Hyp.
Significance and Impact of the Study:Trans‐4‐Hydroxy‐l‐proline (trans‐Hyp) is a valuable chiral building block for the synthesis of pharmaceutical intermediates. Unsatisfactory microbial bioconversion resulted in a low yield of trans‐Hyp. In this study, we blocked the unwanted blunting pathways of host strain and make the cell growth couple with the trans‐Hyp synthesis from glucose. Finally, a recombinant Escherichia coli with short‐cut and efficient trans‐Hyp biosynthetic pathway was obtained. It provided a theoretical basis for commercial production of trans‐Hyp.
Significance and Impact of the Study:Trans‐4‐Hydroxy‐l‐proline (trans‐Hyp) is a valuable chiral building block for the synthesis of pharmaceutical intermediates. Unsatisfactory microbial bioconversion resulted in a low yield of trans‐Hyp. In this study, we blocked the unwanted blunting pathways of host strain and make the cell growth couple with the trans‐Hyp synthesis from glucose. Finally, a recombinant Escherichia coli with short‐cut and efficient trans‐Hyp biosynthetic pathway was obtained. It provided a theoretical basis for commercial production of trans‐Hyp.
Abstract
The water octamer with its cubic structure consisting of six four-membered rings presents an excellent cluster system for unraveling the cooperative interactions driven by subtle changes in ...the hydrogen-bonding topology. Despite prediction of many distinct structures, it has not been possible to extract the structural information encoded in their vibrational spectra because this requires size-selectivity of the neutral clusters with sufficient resolution to identify the contributions of the different isomeric forms. Here we report the size-specific infrared spectra of the isolated cold, neutral water octamer using a scheme based on threshold photoionization using a tunable vacuum ultraviolet free electron laser. A plethora of sharp vibrational bands features are observed. Theoretical analysis of these patterns reveals the coexistence of five cubic isomers, including two with chirality. The relative energies of these structures are found to reflect topology-dependent, delocalized multi-center hydrogen-bonding interactions. These results demonstrate that even with a common structural motif, the degree of cooperativity among the hydrogen-bonding network creates a hierarchy of distinct species. The implications of these results on possible metastable forms of ice are speculated.
Infrared spectroscopic study of neutral water clusters is crucial to understanding of the hydrogen-bonding networks in liquid water and ice. Here we report infrared spectra of size-selected neutral ...water clusters, (H₂O)n (n = 3–6), in the OH stretching vibration region, based on threshold photoionization using a tunable vacuum ultraviolet free-electron laser. Distinct OH stretch vibrational fundamentals observed in the 3,500–3,600-cm−1 region of (H₂O)₅ provide unique spectral signatures for the formation of a noncyclic pentamer, which coexists with the global-minimum cyclic structure previously identified in the gas phase. The main features of infrared spectra of the pentamer and hexamer, (H₂O)n (n = 5 and 6), span the entire OH stretching band of liquid water, suggesting that they start to exhibit the richness and diversity of hydrogenbonding networks in bulk water.
With the aim of gathering temporal trends on bacterial epidemiology and resistance from multiple laboratories in China, the CHINET surveillance system was organized in 2005. Antimicrobial ...susceptibility testing was carried out according to a unified protocol using the Kirby-Bauer method or automated systems. Results were analyzed according to Clinical and Laboratory Standards Institute (CLSI) 2014 definitions. Between 2005 and 2014, the number of bacterial isolates ranged between 22 774 and 84 572 annually. Rates of extended-spectrum β-lactamase production among Escherichia coli isolates were stable, between 51.7 and 55.8%. Resistance of E. coli and Klebsiella pneumoniae to amikacin, ciprofloxacin, piperacillin/tazobactam and cefoperazone/sulbactam decreased with time. Carbapenem resistance among K. pneumoniae isolates increased from 2.4 to 13.4%. Resistance of Pseudomonas aeruginosa strains against all of antimicrobial agents tested including imipenem and meropenem decreased with time. On the contrary, resistance of Acinetobacter baumannii strains to carbapenems increased from 31 to 66.7%. A marked decrease of methicillin resistance from 69% in 2005 to 44.6% in 2014 was observed for Staphylococcus aureus. Carbapenem resistance rates in K. pneumoniae and A. baumannii in China are high. Our results indicate the importance of bacterial surveillance studies.
Cross-resonance (CR) gates have emerged as a promising scheme for fault-tolerant quantum computation with fixed-frequency qubits. We experimentally implement an entangling CR gate by using a ...microwave-only control in a tunable coupling superconducting circuit, where the tunable coupler provides extra degrees of freedom to verify optimal conditions for constructing a CR gate. By developing a three-qubit Hamiltonian tomography protocol, we systematically investigate the dependency of gate fidelities on spurious qubit interactions and present the first experimental approach to the evaluation of the perturbation impact arising from spectator qubits. Our results reveal that the spectator qubits lead to reductions in CR gate fidelity dependent on Z Z interactions and particular frequency detunings between spectator and gate qubits. The target spectator demonstrates a more serious impact than the control spectator under a standard echo pulse scheme, whereas the degradation of gate fidelity is observed up to 22.5% as both the spectators are present with a modest ZZ coupling to the computational qubits. Our experiments uncover an optimal CR operation regime, and the method we develop here can readily be applied to improving other kinds of two-qubit gates in large-scale quantum circuits.
PDF
