scholarly journals Improving the sorting efficiency of maize haploid kernels using an NMR-based method with oil content double thresholds

Plant Methods ◽  
2021 ◽  
Vol 17 (1) ◽  
Author(s):  
Yanzhi Qu ◽  
Zonghua Liu ◽  
Yazhou Zhang ◽  
Jiwei Yang ◽  
Haochuan Li
Keyword(s):  
Oil Content ◽  
High Efficiency ◽  
Lower Boundary ◽  
Kernel Weight ◽  
Breeding Cycle ◽  
Threshold Method ◽  
Discrimination Rate ◽  
Sorting Efficiency ◽  
Double Threshold

Abstract Background Maize haploid breeding technology can be used to rapidly develop homozygous lines, significantly shorten the breeding cycle and improve breeding efficiency. Rapid and accurate sorting haploid kernels is a prerequisite for the large-scale application of this technology. At present, the automatic haploid sorting based on nuclear magnetic resonance (NMR) using a single threshold method has been realized. However, embryo-aborted (EmA) kernels are usually produced during in vivo haploid induction, and both haploids and EmA kernels have lower oil content and are separated together using a single threshold method based on NMR. This leads to a higher haploid false discrimination rate (FDR) and requires secondary manual sorting to select the haploid kernels from the mixtures, which increases the sorting cost and decreases the haploid sorting efficiency. In order to improve the correct discrimination rate (CDR) in sorting haploids, a method to distinguish EmA kernels is required. Results Single kernel weight and oil content were measured for the diploid, haploid, and EmA kernels derived from three maize hybrids and nine inbred lines by in vivo induction. The results showed that the distribution of oil content showed defined boundaries between the three types of kernels, while the single kernel weight didn't. According to the distribution of oil content in the three types of kernels, a double-threshold method was proposed to distinguish the embryo-aborted kernels, haploid and diploid kernels based on NMR and their oil content. The double thresholds were set based on the minimum oil content of diploid kernels and the maximum content of EmA kernels as the upper and lower boundary values, respectively. The CDR of EmA kernels in different maize materials was > 97.8%, and the average FDR was reduced by 27.9 percent. Conclusions The oil content is an appropriate indicator to discriminate diploid, haploid and EmA kernels. An oil content double-threshold method based on NMR was first developed in this study to identify the three types of kernels. This methodology could reduce the FDR of haploids and improve the sorting efficiency of automated sorting system. Thus, this technique represents a potentially efficient method for haploid sorting and provides a reference for the process of automated sorting of haploid kernels with high efficiency using NMR.

Metabolism and Distribution of Novel Tumor Targeting Drugs In Vivo

2020 ◽  
Vol 21 (13) ◽  
pp. 996-1008
Author(s):  
Mengli Wang ◽  
Qiuzheng Du ◽  
Lihua Zuo ◽  
Peng Xue ◽  
Chao Lan ◽  
...  
Keyword(s):  
Monoclonal Antibodies ◽  
Small Molecule ◽  
High Efficiency ◽  
Tumor Therapy ◽  
Research Progress ◽  
Future Research ◽  
Pharmacokinetic Parameters ◽  
Molecular Characteristics ◽  
Targeted Drugs

Background: As a new tumor therapy, targeted therapy is becoming a hot topic due to its high efficiency and low toxicity. Drug effects of targeted tumor drugs are closely related to pharmacokinetics, so it is important to understand their distribution and metabolism in vivo. Methods: A systematic review of the literature on the metabolism and distribution of targeted drugs over the past 20 years was conducted, and the pharmacokinetic parameters of approved targeted drugs were summarized in combination with the FDA's drug instructions. Targeting drugs are divided into two categories: small molecule inhibitors and monoclonal antibodies. Novel targeting drugs and their mechanisms of action, which have been developed in recent years, are summarized. The distribution and metabolic processes of each drug in the human body are reviewed. Results: In this review, we found that the distribution and metabolism of small molecule kinase inhibitors (TKI) and monoclonal antibodies (mAb) showed different characteristics based on the differences of action mechanism and molecular characteristics. TKI absorbed rapidly (Tmax ≈ 1-4 h) and distributed in large amounts (Vd > 100 L). It was mainly oxidized and reduced by cytochrome P450 CYP3A4. However, due to the large molecular diameter, mAb was distributed to tissues slowly, and the volume of distribution was usually very low (Vd < 10 L). It was mainly hydrolyzed and metabolized into peptides and amino acids by protease hydrolysis. In addition, some of the latest drugs are still in clinical trials, and the in vivo process still needs further study. Conclusion: According to the summary of the research progress of the existing targeting drugs, it is found that they have high specificity, but there are still deficiencies in drug resistance and safety. Therefore, the development of safer and more effective targeted drugs is the future research direction. Meanwhile, this study also provides a theoretical basis for clinical accurate drug delivery.

scholarly journals A novel dephosphorylation targeting chimera selectively promoting tau removal in tauopathies

2021 ◽  
Vol 6 (1) ◽  
Author(s):  
Jie Zheng ◽  
Na Tian ◽  
Fei Liu ◽  
Yidian Zhang ◽  
Jingfen Su ◽  
...  
Keyword(s):  
Neurodegenerative Disorders ◽  
Protein Phosphatase ◽  
High Efficiency ◽  
Microtubule Assembly ◽  
Hyperphosphorylated Tau ◽  
Phosphatase 2A ◽  
Dependent Learning ◽  
The Brain

AbstractIntraneuronal accumulation of hyperphosphorylated tau is a hallmark pathology shown in over twenty neurodegenerative disorders, collectively termed as tauopathies, including the most common Alzheimer’s disease (AD). Therefore, selectively removing or reducing hyperphosphorylated tau is promising for therapies of AD and other tauopathies. Here, we designed and synthesized a novel DEPhosphorylation TArgeting Chimera (DEPTAC) to specifically facilitate the binding of tau to Bα-subunit-containing protein phosphatase 2A (PP2A-Bα), the most active tau phosphatase in the brain. The DEPTAC exhibited high efficiency in dephosphorylating tau at multiple AD-associated sites and preventing tau accumulation both in vitro and in vivo. Further studies revealed that DEPTAC significantly improved microtubule assembly, neurite plasticity, and hippocampus-dependent learning and memory in transgenic mice with inducible overexpression of truncated and neurotoxic human tau N368. Our data provide a strategy for selective removal of the hyperphosphorylated tau, which sheds new light for the targeted therapy of AD and related-tauopathies.

scholarly journals In vivo genome editing in mouse restores dystrophin expression in Duchenne muscular dystrophy patient muscle fibers

2021 ◽  
Vol 13 (1) ◽  
Author(s):  
Menglong Chen ◽  
Hui Shi ◽  
Shixue Gou ◽  
Xiaomin Wang ◽  
Lei Li ◽  
...  
Keyword(s):  
Duchenne Muscular Dystrophy ◽  
Muscular Dystrophy ◽  
Mouse Model ◽  
Genome Editing ◽  
Large Scale ◽  
Gene Editing ◽  
High Efficiency ◽  
Muscle Fibers ◽  
Muscle Cells

Abstract Background Mutations in the DMD gene encoding dystrophin—a critical structural element in muscle cells—cause Duchenne muscular dystrophy (DMD), which is the most common fatal genetic disease. Clustered regularly interspaced short palindromic repeat (CRISPR)-mediated gene editing is a promising strategy for permanently curing DMD. Methods In this study, we developed a novel strategy for reframing DMD mutations via CRISPR-mediated large-scale excision of exons 46–54. We compared this approach with other DMD rescue strategies by using DMD patient-derived primary muscle-derived stem cells (DMD-MDSCs). Furthermore, a patient-derived xenograft (PDX) DMD mouse model was established by transplanting DMD-MDSCs into immunodeficient mice. CRISPR gene editing components were intramuscularly delivered into the mouse model by adeno-associated virus vectors. Results Results demonstrated that the large-scale excision of mutant DMD exons showed high efficiency in restoring dystrophin protein expression. We also confirmed that CRISPR from Prevotella and Francisella 1(Cas12a)-mediated genome editing could correct DMD mutation with the same efficiency as CRISPR-associated protein 9 (Cas9). In addition, more than 10% human DMD muscle fibers expressed dystrophin in the PDX DMD mouse model after treated by the large-scale excision strategies. The restored dystrophin in vivo was functional as demonstrated by the expression of the dystrophin glycoprotein complex member β-dystroglycan. Conclusions We demonstrated that the clinically relevant CRISPR/Cas9 could restore dystrophin in human muscle cells in vivo in the PDX DMD mouse model. This study demonstrated an approach for the application of gene therapy to other genetic diseases.

scholarly journals Tissue-Specific Transcriptional Targeting of a Replication-Competent Retroviral Vector

2002 ◽  
Vol 76 (24) ◽  
pp. 12783-12791 ◽  
Author(s):  
Christopher R. Logg ◽  
Aki Logg ◽  
Robert J. Matusik ◽  
Bernard H. Bochner ◽  
Noriyuki Kasahara
Keyword(s):  
Tumor Cells ◽  
Viral Vectors ◽  
High Efficiency ◽  
Leukemia Virus ◽  
Transduction Efficiency ◽  
Promoter Strength ◽  
Cell Type ◽  
Cell Type Specificity ◽  
Tissue Specific

ABSTRACT The inability of replication-defective viral vectors to efficiently transduce tumor cells in vivo has prevented the successful application of such vectors in gene therapy of cancer. To address the need for more efficient gene delivery systems, we have developed replication-competent retroviral (RCR) vectors based on murine leukemia virus (MLV). We have previously shown that such vectors are capable of transducing solid tumors in vivo with very high efficiency. While the natural requirement of MLV infection for cell division imparts a certain degree of specificity for tumor cells, additional means for confining RCR vector replication to tumor cells are desirable. Here, we investigated the parameters critical for successful tissue-specific transcriptional control of RCR vector replication by replacing various lengths of the MLV enhancer/promoter with sequences derived either from the highly prostate-specific probasin (PB) promoter or from a more potent synthetic variant of the PB promoter. We assessed the transcriptional specificity of the resulting hybrid long terminal repeats (LTRs) and the cell type specificity and efficiency of replication of vectors containing these LTRs. Incorporation of PB promoter sequences effectively restricted transcription from the LTR to prostate-derived cells and imparted prostate-specific RCR vector replication but required the stronger synthetic promoter and retention of native MLV sequences in the vicinity of the TATA box for optimal replicative efficiency and specificity. Our results have thus identified promoter strength and positioning within the LTR as important determinants for achieving both high transduction efficiency and strict cell type specificity in transcriptionally targeted RCR vectors.

Gastric cancer is the world's second-largest death cause. Peptides can be used to deliver radiation or other fatal chemicals to tumors

2021 ◽  
Author(s):  
Moataz Dowaidar
Keyword(s):  
Gastric Cancer ◽  
High Efficiency ◽  
Specific Activity ◽  
High Specific Activity ◽  
Systemic Circulation ◽  
Efficient Delivery ◽  
Liver And Kidney ◽  
Targeting Ability ◽  
Therapeutic Research

Gastric cancer is the world's second-largest death cause. Developing suitable medical therapies can help individuals live longer. So far, GC treatment has depended on several pharmaceutical techniques. Chemotherapy and surgery are GC patients' most frequent treatment choices. The most major hurdles to effective GC therapy are chemotherapeutic resistance and non-selective targeting. Recent GC-targeted therapeutic research has focused on building more selective and effective anti-GC pharmacological approaches. Because molecular focused therapy can greatly exacerbate the current inefficacy of normal GC therapy procedures, peptide base synthesis can be used as a carrier to deliver radiation or other fatal chemicals to tumor locations with precise protein overexpression. Different types of peptides with special binding affinity to GC overexpressed receptors have been identified for targeted therapy and imaging. Although some of these peptides have excellent GC targeting ability, they also need great GC penetration capacity and no systemic in vivo toxicity before they can be employed in clinical studies. One of these peptides' most notable limitations is their short plasma half-life, limiting their efficient delivery to tumor locations. Sluggish binding pharmacokinetics, along with in vivo instability, can produce targeted treatment failure. Using an appropriate modification strategy to boost blood circulation time may be advantageous.The key to producing successful, innovative anti-cancer targeting drugs with specific targeting capabilities is to mark the peptide with distinct diagnostic and therapeutic radioisotopes. Although a peptide's radiolabeling or enzymatic degradation may not affect its targeting capabilities, the radiation dose delivery impact on it is obvious. Selecting an appropriate type of radionuclide to achieve high-specific activity, using a simple and high-efficiency radiolabeling process, and selecting an adequate spacer and chelator to manage peptide biodistribution are all important considerations when designing a peptide-based radiopharmaceutical. High internalization and significant systemic circulation washout are other essential tumor targeting needs. Many of the peptides described in this work lack these critical features. The radiolabeled peptide should also remain intact and have a short blood washout period, allowing targeted imaging and therapy. SPECT and PET are the most extensively used technologies in nuclear medicine. Although PET has a greater resolution, SPECT technology gives a comparable sensitivity at a lesser cost. Combining fast binding pharmacokinetics with suitable stability in vivo can result in efficient tumor contrast. Non-target liver and kidney accumulation is required when employing radiolabeled peptides to target GC. When a radiolabeled peptide accumulates more in the liver and intestine than in the GC tumor, the image quality degrades. However, using the proper chelator and spacer can assist decrease non-target accumulation in the kidneys. Finally, considering all these conditions and being positive, it is conceivable to produce a unique peptide with avid binding to GC cells.

Combinatorial Synthesis of Novel 3/5(3,5)-(Di)nitro/chloropaeonol Carbonyl Hydrazone Derivatives as Nematicidal Agents

2021 ◽  
Vol 24 ◽  
Author(s):  
Genqiang Chen ◽  
Lina Zhu ◽  
Yanfei Xia ◽  
Jinming Yang ◽  
Song Zhang ◽  
...  
Keyword(s):  
High Efficiency ◽  
Biological Activities ◽  
Science Research ◽  
Nematicidal Activity ◽  
Effective Control ◽  
Root Bark ◽  
Naturally Occurring ◽  
Whole Plant ◽  
Wide Range

Background: Developing the high-efficiency and low-risk small-molecule green-nematocide is the key of effective control of the nematodes. Paeonol, is a naturally occurring phenolic compound, isolated from the root bark of Paeonia suffruticosa and the whole plant of Cynanchum paniculatum. Due to its crucial phenolic ketone skeleton, modern biological science research has indicated that paeonol has a wide range of biological activities. The structural modification of paeonol into paeonol carbonyl hydrazone derivatives is a potential approach for the development of novel nematodes, which showed more toxicity than paeonol. However, there are no reports on the nematicidal activity of paeonol carbonyl hydrazone derivatives to control Heterodera glycines. Results: We always endeavor to discover and develop biorational natural products-based pesticidal agents, 4 significant intermediates and 21 novel 3/5(3,5)-(di)nitro/chloropaeonol carbonyl hydrazone derivatives were prepared, and their structures well characterized by 1H NMR, HRMS, MS, and mp. Due to the steric hindrance, the substituents on the C=N double bond of all hydrazine compounds adopted E configuration. Results of nematicidal activity revealed that, among all compounds, especially 5-nitropaeonol (5) and 3,5-dinitropaeonol (7) displayed the most potent nematicidal activity H. glycines in vivo with LC50 values of 0.0323 and 0.0367 mg/mL, respectively. Conclusion: It suggested that for the 3/5(3,5)-(di)nitro/chloropaeonol carbonyl hydrazone derivatives, a nitro group introduced at C5 position of 1 was necessary for obtaining the potent compound as nematicidal agents. These preliminary results will pave the way for further modification of paeonol in the development of potential new nematicides.

scholarly journals Gene Transfer to the Desiccation-Tolerant CyanobacteriumChroococcidiopsis

2001 ◽  
Vol 183 (7) ◽  
pp. 2298-2305 ◽  
Author(s):  
Daniela Billi ◽  
E. Imre Friedmann ◽  
Richard F. Helm ◽  
Malcolm Potts
Keyword(s):  
High Efficiency ◽  
Genetic Manipulation ◽  
Recipient Cell ◽  
Conjugative Transfer ◽  
Lower Efficiency ◽  
Genetic Studies ◽  
Variable Regions ◽  
Multiple Cycles ◽  
Experimental Strain

ABSTRACT The coccoid cyanobacterium Chroococcidiopsisdominates microbial communities in the most extreme arid hot and cold deserts. These communities withstand constraints that result from multiple cycles of drying and wetting and/or prolonged desiccation, through mechanisms which remain poorly understood. Here we describe the first system for genetic manipulation ofChroococcidiopsis. Plasmids pDUCA7 and pRL489, based on the pDU1 replicon of Nostoc sp. strain PCC 7524, were transferred to different isolates of Chroococcidiopsisvia conjugation and electroporation. This report provides the first evidence that pDU1 replicons can be maintained in cyanobacteria other than Nostoc and Anabaena. Following conjugation, both plasmids replicated inChroococcidiopsis sp. strains 029, 057, and 123 but not in strains 171 and 584. Both plasmids were electroporated into strains 029 and 123 but not into strains 057, 171, and 584. Expression of P psbA-luxAB on pRL489 was visualized through in vivo luminescence. Efficiencies of conjugative transfer for pDUCA7 and pRL489 into Chroococcidiopsissp. strain 029 were approximately 10−2 and 10−4 transconjugants per recipient cell, respectively. Conjugative transfer occurred with a lower efficiency into strains 057 and 123. Electrotransformation efficiencies of about 10−4electrotransformants per recipient cell were achieved with strains 029 and 123, using either pDUCA7 or pRL489. Extracellular deoxyribonucleases were associated with each of the five strains. Phylogenetic analysis, based upon the V6 to V8 variable regions of 16S rRNA, suggests that desert strains 057, 123, 171, and 029 are distinct from the type species strain Chroococcidiopsis thermalis PCC 7203. The high efficiency of conjugative transfer of Chroococcidiopsis sp. strain 029, from the Negev Desert, Israel, makes this a suitable experimental strain for genetic studies on desiccation tolerance.

scholarly journals Recombinogenic Flap Ligation Pathway for Intrinsic Repair of Topoisomerase IB-Induced Double-Strand Breaks

2000 ◽  
Vol 20 (21) ◽  
pp. 8059-8068 ◽  
Author(s):  
Chonghui Cheng ◽  
Stewart Shuman
Keyword(s):  
High Efficiency ◽  
Strand Break ◽  
Strand Transfer ◽  
Strand Breaks ◽  
Genomic Deletions ◽  
Topoisomerase Ib ◽  
Dna Strand ◽  
Recombination Pathway

ABSTRACT Topoisomerase IB catalyzes recombinogenic DNA strand transfer reactions in vitro and in vivo. Here we characterize a new pathway of topoisomerase-mediated DNA ligation in vitro (flap ligation) in which vaccinia virus topoisomerase bound to a blunt-end DNA joins the covalently held strand to a 5′ resected end of a duplex DNA containing a 3′ tail. The joining reaction occurs with high efficiency when the sequence of the 3′ tail is complementary to that of the scissile strand immediately 5′ of the cleavage site. A 6-nucleotide segment of complementarity suffices for efficient flap ligation. Invasion of the flap into the duplex apparently occurs while topoisomerase remains bound to DNA, thereby implying a conformational flexibility of the topoisomerase clamp around the DNA target site. The 3′ flap acceptor DNA mimics a processed end in the double-strand-break-repair recombination pathway. Our findings suggest that topoisomerase-induced breaks may be rectified by flap ligation, with ensuing genomic deletions or translocations.

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