The r-X1 deletion induces terminal deficiencies in the maize B chromosome.

In addition to causing the nondisjunction of maize B and normal A chromosomes at the second megaspore division during embryo sac development, the r-X1 deletion results in terminal deficiencies (TDs) in various A chromosomal arms, but whether the r-X1 deletion also induces TDs of the maize B chromosome remains unknown. To answer this question, the chromosomal composition in the r-X1-containing progeny of r-X1/R-r female parents carrying two standard B chromosomes was determined. Nine of 104 (8.

The maize B chromosome is capable of expressing microRNAs and altering the expression of microRNAs derived from A chromosomes.

Supernumerary B chromosomes (Bs) are nonessential chromosomes that are considered genetically inert. However, the maize B carries control elements that direct its behavior, such as that of nondisjunction, during the second pollen mitosis, and affects normal A chromosomes during cell division. Recently, the maize B has been found to contain transcriptionally active sequences and to affect the transcription of genes on A chromosomes.

Development and In Vitro Evaluation of Linear PEI-Shelled Heparin/Berberine Nanoparticles in Human Osteosarcoma U-2 OS Cells.

Berberine (BBR), a natural isoquinoline alkaloid derived from Chinese herbs, exerts many biological effects, including antiviral, antimicrobial, antidiarrhea, anti-inflammatory, and antitumor effects. In this study, a novel berberine nanoparticle (NP) consisting of heparin (HP) and BBR with or without being shelled with linear polyethyleneimine (LPEI) was developed to enhance its antitumor activity on osteosarcoma U-2 OS cells. With varying ratios of HP to BBR, HP/BBR NPs had a size ranging from 218.

Analysis of B chromosome nondisjunction induced by the r-X1 deficiency in maize.

The maize B chromosome typically undergoes nondisjunction during the second microspore division. For normal A chromosomes, the r-X1 deficiency in maize can induce nondisjunction during the second megaspore and first microspore divisions. However, it is not known whether the r-X1 deficiency also induces nondisjunction of the maize B chromosome during these cell divisions.

Re-emergence of Lilium callosum Sieb. et Zucc. in Taiwan after a fire allows propagation and renews the possibility of conservation.

Background: Lilium callosum is native to Taiwan, but little is known about it since it has been considered extinct since 1915. After the rediscovery of this rare species after a fire in 2011 in Tunghsiao Township, intensive work has been conducted to count the number in the wild population, to develop a conservation strategy, and to understand its reproductive characteristics and even economic potential.

Results: To conserve the germplasm of this population, three scales from a wild L.

Novel PEI/Poly-γ-Gutamic Acid Nanoparticles for High Efficient siRNA and Plasmid DNA Co-Delivery.

The efficient delivery of sufficient amounts of nucleic acids into target cells is critical for successful gene therapy and gene knockdown. The DNA/siRNA co-delivery system has been considered a promising approach for cancer therapy to simultaneously express and inhibit tumor suppressor genes and overexpressed oncogenes, respectively, triggering synergistic anti-cancer effects. Polyethylenimine (PEI) has been identified as an efficient non-viral vector for transgene expression.

Cytomolecular characterization and origin of de novo formed maize B chromosome variants.

B chromosomes are dispensable elements that occur in many species, including maize. The maize B chromosome is acrocentric and highly heterochromatic and undergoes nondisjunction during the second pollen mitosis. In this study, we determined the genetic behavior and organization of two naturally occurring B chromosome variants (designated B(ta) and B(tb)).

Development and mapping of CL-repeat display markers on the maize B chromosome.

The CL-repeat is a repetitive sequence that is unique to the maize B chromosome, where it resides in the centromeric knob and the first 3 distal heterochromatic regions of the long arm. Given this organization, it would be desirable to identify molecular markers that are specifically distributed in the B chromosome. In this report, the CL-repeat has been used to develop a class of molecular markers for the maize B chromosome.

Characterization of four B-chromosome-specific RAPDs and the development of SCAR markers on the maize B-chromosome.

Understanding the molecular organization of the maize B-chromosome is hindered by its high homology with A-chromosomes. Recently, various approaches have been employed to overcome this hindrance, and several B-chromosome-specific sequences have been identified. Here, we cloned and characterized four previously published B-chromosome-specific RAPD fragments in detail.

Characterization of maize B-chromosome-related transcripts isolated via cDNA-AFLP.

The maize B-chromosome consists mainly of heterochromatin and is considered to be genetically inert. However, the B-chromosome contains euchromatin that carries control elements that direct its behaviors during cell division, such as nondisjunction during the second pollen mitosis. To determine the transcriptional activity of the B-chromosome, complementary DNA-amplified fragment length polymorphism analysis was applied to five inbred maize lines with and without B-chromosomes.

Using ITS2 PCR-RFLP to generate molecular markers for authentication of Sophora flavescens Ait.

Background: Dried root of Sophora flavescens Ait. is a medicinal material occasionally misused or adulterated by other species similar in appearance. In this study the internal transcribed spacer (ITS) regions of DNA samples of S.

Characterization of satellite CentC repeats from heterochromatic regions on the long arm of maize B-chromosome.

The B-chromosome of maize contains an A-chromosome centromere-specific satellite CentC repeat in its centromere region (CENB) and at multiple locations in its distal heterochromatic regions (BDHs). Because CentC is highly repetitive, it is a challenge to study CentC sequences within individual centromeres or chromosome regions. The combined structure of CentC and a BDH-specific CL-repeat has allowed us to isolate CentC sequences from BDHs.

Evolution of the heterochromatic regions on maize B long arm based on the sequence structure of CL-repeat variants.

Evolution of heterochromatic regions in the B long arm was studied in two directions: construction of a phylogenetic tree from mutational variants of CL-repeat and analysis of the XbaI fragments carrying CL-repeat and the repeat structural variants. Using tertiary trisomes and hypoploids of a set of B-10L translocations, the fragments associated with CL-repeat and the variants in each of the three distal heterochromatic (DH) regions were identified. Twenty fragments comprising the CL-repeat were observed in the B-chromosome, and each was assigned to an individual DH region.

Complex genomic organization of Indian muntjac centromeric DNA.

A 69-kb Indian muntjac bacterial artificial chromosome (BAC) clone that screened positive for Cervid satellites I and IV was selected for complete sequence analysis and further characterization. The sequences of this BAC clone were found in the centromeres and in some interstitial sites of Indian muntjac chromosomes. Sequence analyses showed that the BAC clone contained a 14.

Localization and transcription of a retrotransposon-derived element on the maize B chromosome.

Dispensable chromosomes in addition to the normal complement in diverse taxa are called B chromosomes. The maize B chromosome is discernible in mitotic chromosome spreads as a small compact chromosome composed mainly of heterochromatin. Although much of this chromosome consists of repetitive elements common to the A chromosomes, several sequences specific to the B chromosome have been identified.

Expression and functional analysis of pituitary tumor transforming gene-1 [corrected] in uterine leiomyomas.

Pituitary tumor-transforming gene-1 (PTTG-1) is a novel protooncogene overexpressed in numerous cancer cell lines and cancers. In this study we elucidate the expression of PTTG-1 in uterine leiomyomas and its functional role in the development of this disease. By comparing 23 pairs of leiomyomas and matched pairs of myometria, we found that the expression of PTTG-1 is significantly elevated in leiomyoma.

Molecular organization of large fragments in the maize B chromosome: indication of a novel repeat.

The supernumerary B chromosome has no apparent effects on plant growth, and its molecular makeup is difficult to unravel, due to its high homology to the normal complement, which prevents conventional cloning. This difficulty was overcome previously by microdissecting the B chromosome under the microscope to result in 19 B clones, one of which is B specific and highly repetitive, dispersing over one-third of the B long arm and most regions of the centromeric knob. To gain insights into the molecular structure of the B chromosome, this sequence was used to screen a genomic library constructed from W22 carrying 16 B's.

Cloning and characterization of maize B chromosome sequences derived from microdissection.

Isolation of sequences from the maize B chromosome is always hampered by its high homology with the normal complements. In this study, this handicap was overcome by cloning the sequences from the pachytene B chromosomes dissected out of a slide by a micromanipulator followed by degenerate oligonucleotide-primed PCR. The isolated sequences were found to hybridize with genomic DNA in a B-dosage-dependent manner and with the pachytene B chromosome by fluorescence in situ hybridization (FISH), corroborating their B origin.