scholarly journals Polyploidy and its implications in plants breeding – A review

2021 ◽  
Vol 8 (3) ◽  
pp. 1-9
Author(s):  
Masreshaw Yirga
Keyword(s):  
Crop Breeding ◽  
Improvement Program ◽  
Consecutive Generation ◽  
Homologous Chromosomes ◽  
Major Mechanism ◽  
New Crops ◽  
Seedless Fruits ◽  
Cytological Characteristics ◽  
Is Development ◽  
Bridge Crossing

Polyploidy is a prominent force of shaping the evolution of in most of ferns and flowering plants. Polyploidy has tremendous contribution in plants improvement program. It is the polyploidy breeding through which new crops can be developed and interspecific genes can be transferred and also the origin of crops can be traced. It is now an interesting field of study to reveal the evolution of crop plants and utilizing their variability in the field of crop breeding. Polyploidy generally differ markedly from their progenitors in morphological, ecological, physiological and cytological characteristics that can contribute both to exploitation of a new niche and to reproductive isolation. As a result, polyploidy is a major mechanism of adaptation and speciation in plants. Another implication of polyploidy is development heterosis in plant breeding. Unlike diploids which may lose heterosis with each consecutive generation due to segregation, polyploidy imposes pairing of homologous chromosomes, thus preventing intergenomic recombination. In this way, heterozygosity is maintained throughout generations. One of the immediate and obvious consequences of polyploidy in plants is an increase in cell size which in turn leads to enlarged plant organs relative to diploids. It is also used in bridge crossing, development of seedless fruits like watermelon and production of apomictic crops.

scholarly journals CRISPR targeting of MEIOTIC-TOPOISOMERASE VIB-dCas9 to a recombination hotspot is insufficient to increase crossover frequency in Arabidopsis

2021 ◽  
Author(s):  
Nataliya E. Yelina ◽  
Sabrina Gonzalez-Jorge ◽  
Dominique Hirsz ◽  
Ziyi Yang ◽  
Ian R. Henderson
Keyword(s):  
Meiotic Recombination ◽  
Crop Improvement ◽  
Double Strand Breaks ◽  
Crossover Frequency ◽  
Dna Double Strand Breaks ◽  
Crop Breeding ◽  
Catalytic Subunits ◽  
Strand Breaks ◽  
Homologous Chromosomes ◽  
Meiotic Crossover

AbstractDuring meiosis, homologous chromosomes pair and recombine, which can result in reciprocal crossovers that increase genetic diversity. Crossovers are unevenly distributed along eukaryote chromosomes and show repression in heterochromatin and the centromeres. Within the chromosome arms crossovers are often concentrated in hotspots, which are typically in the kilobase range. The uneven distribution of crossovers along chromosomes, together with their low number per meiosis, creates a limitation during crop breeding, where recombination can be beneficial. Therefore, targeting crossovers to specific genome locations has the potential to accelerate crop improvement. In plants, meiotic crossovers are initiated by DNA double strand breaks (DSBs) that are catalysed by SPO11 complexes, which consist of two catalytic (SPO11-1 and SPO11-2) and two non-catalytic subunits (MTOPVIB). We used the model plant Arabidopsis thaliana to target a dCas9-MTOPVIB fusion protein to the 3a crossover hotspot via CRISPR. We observed that this was insufficient to significantly change meiotic crossover frequency or pattern within 3a. We discuss the implications of our findings for targeting meiotic recombination within plant genomes.

Ultrastructure of primary spermatocyte in fish (Tilapia: Oreochromis niloticus): The synaptonemal complex

1986 ◽  
Vol 44 ◽  
pp. 288-289
Author(s):  
T. Guha ◽  
A. Q. Siddiqui ◽  
P. F. Prentis
Keyword(s):  
Fine Structure ◽  
Electron Microscope ◽  
Synaptonemal Complex ◽  
Oreochromis Niloticus ◽  
Short Communication ◽  
Primary Spermatocyte ◽  
Mitotic Division ◽  
Meiotic Cell ◽  
Electron Microscope Level ◽  
Homologous Chromosomes

The Primary Spermatocytes represent a stage in spermatogenesis when the first meiotic cell division occurs. They are derived from Spermatogonium or Stem cell through mitotic division. At the zygotene phase of meiotic prophase the Synaptonemal complex appears in these cells in the space between the paired homologous chromosomes. Spermatogenesis and sperm structure in fish have been studied at the electron microscope level in a few species? However, no work has yet been reported on ultrastructure of tilapia, O. niloticus, spermatozoa and spermatogenetic process. In this short communication we are reporting the Ultrastructure of Primary Spermatocytes in tilapia, O. niloticus, and the fine structure of synaptonemal complexes seen in the spermatocyte nuclei.

Residency Training and Hand Surgery Practice Patterns: A National Surgical Quality Improvement Program Database Analysis

2020 ◽  
Author(s):  
James J. Drinane ◽  
Brian Drolet ◽  
Ashit Patel ◽  
Joseph A. Ricci
Keyword(s):  
Quality Improvement ◽  
Residency Training ◽  
Practice Patterns ◽  
Hand Surgery ◽  
Soft Tissue Coverage ◽  
Improvement Program ◽  
Surgical Quality ◽  
Orthopedic Surgeons ◽  
Procedural Volume ◽  
General Surgeons

Abstract Introduction Fellowship-trained hand surgeons may have residency training in either orthopedic, plastic, or general surgery, generating significant variability in education background. To study the effect of different training backgrounds on practice pattern variations, we utilized the NSQIP (National Surgical Quality Improvement Database) database to assess hand surgery volumes and case variety by specialty. Materials and Methods NSQIP years 2008 to 2017 was queried with hand surgery current procedural terminology codes defined by the American Board of Orthopedic Surgery. Procedures were grouped according to type and specialty, and relative rates calculated. Hand society membership data were used to determine if procedural volume for each specialty in each category and overall contribution to the volume of hand surgery performed nationally was distributed in accordance with membership data. Results A total of 145,015 hand surgeries were performed; 13,267 (9.1%) by general surgeons, 28,402 (19.6%) by plastic surgeons, and 103,346 (71.3%) by orthopedic surgeons. Orthopedic surgeons performed significantly more bone, fracture, joint, and tendon cases. General surgeons and plastic surgeons performed higher than expected numbers of soft tissue coverage and cases overall with respective excesses of 183 and 22%. Conclusion Hand surgery is an available fellowship pathway from multiple residencies. Fellowship training does not level the field of real-world practice patterns. Residency training experiences significantly impact practice.

Upper Extremity Free Flap Transfers: An Analysis of the National Surgical Quality Improvement Program Database

2020 ◽  
Author(s):  
George A. Beyer ◽  
Karan Dua ◽  
Neil V. Shah ◽  
Joseph P. Scollan ◽  
Jared M. Newman ◽  
...  
Keyword(s):  
Quality Improvement ◽  
Upper Extremity ◽  
Free Flap ◽  
Quality Improvement Program ◽  
Readmission Rates ◽  
Improvement Program ◽  
Surgical Quality ◽  
Flap Transfer ◽  
Free Flap Transfer ◽  
Reoperation Rates

Abstract Introduction We evaluated the demographics, flap types, and 30-day complication, readmission, and reoperation rates for upper extremity free flap transfers within the National Surgical Quality Improvement Program (NSQIP) database. Materials and Methods Upper extremity free flap transfer patients in the NSQIP from 2008 to 2016 were identified. Complications, reoperations, and readmissions were queried. Chi-squared tests evaluated differences in sex, race, and insurance. The types of procedures performed, complication frequencies, reoperation rates, and readmission rates were analyzed. Results One-hundred-eleven patients were selected (mean: 36.8 years). Most common upper extremity free flaps were muscle/myocutaneous (45.9%) and other vascularized bone grafts with microanastomosis (27.9%). Thirty-day complications among all patients included superficial site infections (2.7%), intraoperative transfusions (7.2%), pneumonia (0.9%), and deep venous thrombosis (0.9%). Thirty-day reoperation and readmission rates were 4.5% and 3.6%, respectively. The mean time from discharge to readmission was 12.5 days. Conclusion Upper extremity free flap transfers could be performed with a low rate of 30-day complications, reoperations, and readmissions.

Blood Management in Total Knee Arthroplasty: A Nationwide Analysis from 2011 to 2018

2020 ◽  
Author(s):  
Jared A. Warren ◽  
John P. McLaughlin ◽  
Robert M. Molloy ◽  
Carlos A. Higuera ◽  
Jonathan L. Schaffer ◽  
...  
Keyword(s):  
Total Knee Arthroplasty ◽  
Platelet Count ◽  
Knee Arthroplasty ◽  
Categorical Variables ◽  
Bleeding Disorders ◽  
Blood Management ◽  
Improvement Program ◽  
Preoperative Anemia ◽  
High Incidence ◽  
Total Knee

AbstractBoth advances in perioperative blood management, anesthesia, and surgical technique have improved transfusion rates following primary total knee arthroplasty (TKA), and have driven substantial change in preoperative blood ordering protocols. Therefore, blood management in TKA has seen substantial changes with the implementation of preoperative screening, patient optimization, and intra- and postoperative advances. Thus, the purpose of this study was to examine changes in blood management in primary TKA, a nationwide sample, to assess gaps and opportunities. The American College of Surgeons National Surgical Quality Improvement Program database was used to identify TKA (n = 337,160) cases from 2011 to 2018. The following variables examined, such as preoperative hematocrit (HCT), anemia (HCT <35.5% for females and <38.5% for males), platelet count, thrombocytopenia (platelet count < 150,000/µL), international normalized ration (INR), INR > 2.0, bleeding disorders, preoperative, and postoperative transfusions. Analysis of variances were used to examine changes in continuous variables, and Chi-squared tests were used for categorical variables. There was a substantial decrease in postoperative transfusions from high of 18.3% in 2011 to a low of 1.0% in 2018, (p < 0.001), as well as in preoperative anemia from a high of 13.3% in 2011 to a low of 9.5% in 2016 to 2017 (p < 0.001). There were statistically significant, but clinically irrelevant changes in the other variables examined. There was a HCT high of 41.2 in 2016 and a low of 40.4 in 2011 to 2012 (p < 0.001). There was platelet count high of 247,400 in 2018 and a low of 242,700 in 201 (p < 0.001). There was a high incidence of thrombocytopenia of 5.2% in 2017 and a low of low of 4.4% in 2018 (p < 0.001). There was a high INR of 1.037 in 2011 and a low of 1.021 in 2013 (p < 0.001). There was a high incidence of INR >2.0 of 1.0% in 2012 to 2015 and a low of 0.8% in 2016 to 2018 (p = 0.027). There was a high incidence of bleeding disorders of 2.9% in 2013 and a low of 1.8% in 2017 to 2018 (p < 0.001). There was a high incidence of preoperative transfusions of 0.1% in 2011 to 2014 and a low of <0.1% in 2015 to 2018 (p = 0.021). From 2011 to 2018, there has been substantial decreases in patients receiving postoperative transfusions after primary TKA. Similarly, although a decrease in patients with anemia was seen, there remains 1 out 10 patients with preoperative anemia, highlighting the opportunity to further improve and address this potentially modifiable risk factor before surgery. These findings may reflect changes during TKA patient selection, optimization, or management, and emphasizes the need to further advance multimodal approaches for perioperative blood management of TKA patients. This is a Level III study.

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