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PubMed2006

Lipid fluorination enables phase separation from fluid phospholipid bilayers.

To probe the effect of lipid fluorination on the formation of lipid domains in phospholipid bilayers, several new fluorinated and non-fluorinated synthetic lipids were synthesised, and the extent of phase separation of these lipids from phospholipid bilayers of different compositions was determined. At membrane concentrations as low as 1% mol/mol, both fluorinated and non-fluorinated lipids were observed to phase separate from a gel-phase (solid ordered) phospholipid matrix, but bilayers in a liquid disordered state caused no phase separation; if the gel-phase samples were heated above the transition temperature, then phase separation was lost. We found incorporation of perfluoroalkyl groups into the lipid enhanced phase separation, to such an extent that phase separation was observed from cholesterol containing bilayers in the liquid ordered phase.

Hydrocarbons, Fluorinated↗
PubMed1977

The separation and characterization of bronchial glycoproteins by density-gradient methods.

1. Sputum samples from a total of 18 asthmatic and chronic bronchitic patients were examined by analytical density-gradient ultracentrifugation. CsBr was used as the dispersal agent and dense electrolyte. 2. The patterns show two main groups of components, banding at about 1.3g/ml and 1.5g/ml; in addition, a few samples showed a further zone at approx. 1.65g/ml. These components were identified as protein, secretory glycoprotein and DNA respectively. The glycoprotein zone was frequently hypersharp, and usually contained two or more partially resolved bands; it was always well resolved from the protein. 3. The glycoprotein components were isolated from nine representative sputum samples by density-gradient ultracentrifugation on a preparative scale. Analytical density-gradient ultracentrifugation was used to monitor the efficiency of the separations. 4. Some sputum samples separated cleanly under these conditions, the glycoprotein being essentially devoid of free protein; in others, separation was apparently incomplete, although computer simulation indicated that the conditions were adequate to ensure separation. Further density-gradient separations in CsCl were necessary with several samples before satisfactory products were obtained; mixtures of CsCl with guanidinium chloride were no more effective than CsCl alone. The reluctance to separate indicates a very strong, but non-covalent, interaction between protein and glycoprotein, probably associated with the gelatinous character of the secretion. 5. The purified glycoprotein components were characterized analytically and physicochemically. They contained N-acetylgalactosamine, N-acetylglucosamine, galactose, fucose and N-acetylneuraminic acid, and had an amino acid composition in which serine, threonine and proline predominated; however, aspartic acid, glutamic acid and cystine were also appreciable. The glycoproteins were of very high molecular weight, and usually showed more than one component in sedimentation velocity; their distribution in a density gradient indicated a substantial, but largely monotonic, density heterogeneity. 6. Thiol reduction decreased the molecular weight very substantially, but the products were relatively more homogeneous than the native materials. The amino acid composition was changed significantly and a small and variable proportion of protein or peptide was liberated. It is concluded that the native materials are disulphide-linked aggregates, probably through a cross-linking peptide, in confirmation of earlier studies.

Amino Acids↗
PubMed2003

Talker separation and sequential stream segregation in listeners with hearing loss: patterns associated with talker gender.

The purpose of this paper was to examine the relations between the ability to separate simultaneous sentences spoken by talkers of different gender and the ability to separate pitch patterns in a sequential stream segregation task. Simultaneous sentence pairs consisting of 1 sentence spoken by a male talker and 1 sentence spoken by a female talker were presented to 11 listeners with sensorineural hearing loss. Listeners were asked to repeat both sentences and were scored on the number of words repeated correctly. Separate scores were obtained for the male and female sentences. Sequential stream segregation was then measured using series of tones consisting of a fixed frequency (A) and a varying frequency tone (B). Tone series were presented in an ABA_ABA_... pattern starting at a varying frequency either below (ascending pattern) or above (descending pattern) the frequency of the fixed 1000 Hz tone. Fusion thresholds, defined as the frequency separation at which listeners could no longer perceptually separate the tones A and B, were obtained for both ascending and descending patterns. There was no significant difference between ascending and descending fusion thresholds based on the group data, but substantial individual differences were observed. Speech recognition scores for the male talker were strongly related to ascending fusion thresholds, but not descending thresholds. In contrast, speech recognition scores for the female talker were strongly related to the descending thresholds, but not the ascending thresholds. For both the male and female talkers, better recognition scores were associated with lower (nearer to normal) fusion thresholds. Results suggest that the importance of streaming in the perceptual separation of talkers may depend on the nature of the information provided by the changing pitch stream.

Aged↗
PubMed2001

Separation between the digestive and the respiratory lumina during the human embryonic period: morphometric study along the tracheo-oesophageal septum.

An isolated tracheo-oesophageal fistula could be caused by close proximity of the epithelia of both organs (O'Rahilly & Müller, 1984; Kluth et al. 1987) at certain embryonic stages, the most frequent location being the tracheal bifurcation. Thus the relative position and degree of separation between the digestive and the respiratory tubes throughout their development may be relevant to the origin of this anomaly. The aim of this study was to analyse along the different segments of the tracheo-oesophageal septum (TES) where the closest relationship between both lumina occurred and what degree of separation was present at each segment. Computer imaging techniques were applied on cross sections of a graded series of normal human embryos (Carnegie stages (CS) 13-23). In addition, the differentiation of the primitive TES was also studied (from CS 12) by light microscopy. Between CS 13 and 16 both tubes tended to separate (phase of separation), principally at the proximal segments of the laryngopharyngeal and the tracheo-oesophageal portions of the TES. During this phase the separation between the trachea and oesophagus was wider than between the larynx and pharynx. From CS 17 to CS 23 the digestive and respiratory lumina reached their widest separation at different levels of the laryngopharyngeal portion. Below these levels they tended to come closer together, principally at the proximal segment of the tracheo-oesophageal portion, but also at the distal part of the laryngopharyngeal portion. During this phase of approximation they reached their closest relationship at the proximal (CS 17) and the distal (from CS 18) segments of the tracheo-oesophageal portion. When finally the distal segment of the trachea (which includes the bifurcation) comes closest to the oesophagus, the coats of both organs have already undergone an appreciable differentiation. According to these observations, the origin of the most frequent isolated tracheo-oesophageal fistula at the bifurcation region could not be explained from the normal development of the TES.

Embryonic and Fetal Development↗
PubMed2000

An evaluation of preoperative ibuprofen for treatment of pain associated with orthodontic separator placement.

Patients undergoing orthodontic treatment can experience significant levels of pain. This study assessed the effectiveness of preoperative ibuprofen in reducing the incidence and the severity of pain after orthodontic separator placement. Sixty-three adolescent patients (mean age, 13 years) were included in this randomized, double-blind, placebo-controlled, prospective study. Patients were randomly assigned to 1 of 3 experimental conditions: (1) 400 mg of ibuprofen taken orally 1 hour before separator placement and a lactose placebo taken orally immediately after the appointment, (2) a lactose placebo taken orally 1 hour before separator placement and 400 mg of ibuprofen taken orally immediately after the appointment, or (3) a lactose placebo taken orally 1 hour before separator placement and again immediately after the appointment. The patient's level of discomfort was assessed with a visual analog scale at 2, 6, and 24 hours, as well as at 2, 3, and 7 days after placement of the orthodontic separators. An analysis of variance and Duncan's multiple range test revealed that 2 hours after their orthodontic appointment the patients who had taken ibuprofen 1 hour before separator placement had significantly less pain with chewing than did the patients who received either ibuprofen postoperatively or a placebo. Additional measures suggest a trend for less pain for this group of patients. These results support the use of pretreatment ibuprofen for patients requiring analgesics for orthodontic discomfort. Future study of the use of preemptive analgesics in orthodontics is warranted.

Adolescent↗
PubMed2006

Pds1/Esp1-dependent and -independent sister chromatid separation in mutants defective for protein phosphatase 2A.

Spindle disruption or DNA damage prevents sister chromatid separation through the activation of checkpoint pathways that inhibit anaphase entry by stabilizing the anaphase inhibitor Pds1. Mutation of CDC55, which encodes a B regulatory subunit of protein phosphatase 2A (PP2A), results in precocious sister chromatid separation when spindle is disrupted. Here we report that decreased Pds1 levels in Deltacdc55 mutants contribute to sister chromatid separation in the presence of nocodazole, a microtubule-depolymerizing drug. However, in the presence of DNA damage, Deltacdc55 mutant cells separate sister chromatids without noticeable decrease of Pds1 or cohesin Mcd1/Scc1 levels. Further analysis demonstrates that Deltacdc55 mutants lose cohesion along the entire chromosomes when the spindle is disrupted. In contrast, separation of sister chromatids is limited to the centromeric regions in Deltacdc55 cells after DNA damage. Moreover, mutation of TPD3, which encodes the A regulatory subunit of PP2A, also results in sister chromatid separation in DNA- or spindle-damage-arrested cells. These data suggest that PP2A regulates sister chromatid cohesion in Pds1-dependent and -independent manners.

Anaphase↗
PubMed1979

Cytoplasmic phase separation in formation of galactosemic cataract in lenses of young rats.

We have determined the age dependence of the characteristics of the cytoplasmic phase separation of lenses from normal and galactosemic young rats. In the normal lens, the temperature at which the phase separation occurs decreases monotonically with age. In the lenses of rats fed with a high galactose diet, the phase separation temperature becomes increasingly higher with the development of galactosemia. When the phase separation temperature becomes higher than the ocular temperature, the nuclear opacity appears in vivo. The opacity is the result of light scattering by spatial fluctuations of the refractive index formed by interspersed regions of two separated phases in the fiber cell cytoplasm. This shows that the nuclear opacity that develops in the lens of galactosemic rats is the manifestation of phase separation of the lens fiber cytoplasm.

Journal Article↗
PubMed1982

Immunochemical analysis of the glucocorticoid receptor: identification of a third domain separate from the steroid-binding and DNA-binding domains.

The glucocorticoid-receptor complex can be subdivided into three separate domains by limited proteolysis with trypsin or alpha-chymotrypsin. The following characteristics can be separated: steroid-binding activity (domain A), DNA-binding activity (domain B), and immunoactivity (domain C). We have previously reported the separation of the steroid-binding domain from the DNA-binding domain by limited proteolysis of the receptor with trypsin. In this paper, we report the detection by immunochemical analysis of a third domain of the glucocorticoid receptor, which does not bind hormone. Immunoactivity was detected by using specific antiglucocorticoid receptor antibodies raised in rabbits against purified rat liver glucocorticoid receptor and the assay used was an enzyme-linked immunosorbent assay. After digestion with alpha-chymotrypsin, the immunoactive region of the receptor (domain C) was separated from the other two domains (A and B). The immunoactive fragment was found to have a Stokes radius of 2.6 nm. Further digestion with alpha-chymotrypsin resulted in separation of the immunoactive fragment to give a fragment having a Stokes radius of 1.4 nm. The immunoactive domain could be separated from the half of the glucocorticoid receptor containing the steroid-binding and the DNA-binding domains (Stokes radius, 3.3 nm), by limited proteolysis of the receptor by alpha-chymotrypsin followed by gel filtration or chromatography on DNA-cellulose.

Animals↗
PubMed1986

Post-separation detection of nucleic acids and proteins by neutron activation.

We describe approaches to neutron activation analysis and their application to post-separation autoradiographic detection of biological compounds. Specifically, we have extended the use of a "direct-labeling" method to the post-separation detection of DNA after gel electrophoresis and to the detection of nucleotides separated by TLC. In addition, we describe a more generally applicable "indirect-labeling" method in which separated compounds of interest are selectively bound to ligands containing highly neutron-activatable elements, such as manganese (55Mn), europium (151Eu), or dysprosium (164Dy), and then irradiated with thermal neutrons. This method is illustrated with nucleotides separated by TLC and with proteins separated by polyacrylamide gel electrophoresis. In contrast to the direct-labeling approach, the indirect-labeling method can be adapted to detect any class of substances for which a highly neutron-activatable, selectively binding ligand is available. The theoretically achievable sensitivity of the indirect-labeling method is in the attomole (10(-18) mol) range.

Activation Analysis↗
PubMed2004

A 50-A separation of the integrin alpha v beta 3 extracellular domain C termini reveals an intermediate activation state.

The integrin alpha(v)beta(3) has been shown to exist in low and high affinity conformations. Activation to the high affinity state is thought to depend on the "switchblade-like" opening, from a low affinity bent conformation with a closed headpiece to an extended form of the integrin with an open headpiece. Activation has been shown to depend on separation of the cytoplasmic domains. How cytoplasmic domain separation is related to separation of the transmembrane domains is unknown, and the distance of separation of the transmembrane domains required for activation has not been defined. A constrained secreted form of alpha(v)beta(3) was engineered that introduced a 50-A separation of the integrin C-terminal tails of the extracellular domains of the alpha(v) and beta(3) subunits. Receptor binding and recognition by ligand-induced binding state (LIBS) monoclonal antibodies demonstrated that the mutant receptor was locked into a low affinity state that was likely in a partially extended conformation but with a closed headpiece. In the presence of RGD peptide, the constrained receptor was able to fully extend, as determined by full exposure of LIBS epitopes. In the presence of the appropriate LIBS antibody, high affinity ligand binding of the constrained receptor was achieved. The results support the existence of transient intermediate activation states of secreted alpha(v)beta(3). Furthermore, these results with the secreted alpha(v)beta(3) receptor support a model for the full-length membrane-bound form of alpha(v)beta(3), whereby a 50-A lateral separation of the integrin alpha(v) and beta(3) transmembrane domains would be sufficient to enforce the switchblade-like opening to the extended conformation but insufficient for full receptor activation.

Alkaline Phosphatase↗
PubMed2005

The role of Polo-like kinase 1 in the inhibition of centrosome separation after ionizing radiation.

Activation of the G2/M cell cycle checkpoint by DNA damage prevents cells from entering mitosis. Centrosome separation is initiated in G2 phase and completed in M phase. This critical process for cell division is targeted by G2/M checkpoint. Here we show that Plk1 signaling plays an important role in regulation of centrosome separation after DNA damage. Constitutively active Plk1 overrides the inhibition of centrosome separation induced by DNA damage. This inhibition is dependent on ATM, but not on Chk2 or Chk1. Nek2 is a key regulator of centrosome separation and is a target of Plk1 in blocking centrosome separation. We found that Plk1 can phosphorylate Nek2 in vitro and interacts with Nek2 in vivo. Down-regulation of Plk1 with RNA interference prevents Nek2-induced centrosome splitting. DNA damage is known to inhibit Plk1 activity. We propose that the DNA damage-induced inhibition of Plk1 leads to inhibition of Nek2 activity and thus prevents centrosome separation.

Cell Cycle Proteins↗
PubMed2005

Multidimensional liquid chromatography separation of intact proteins by chromatographic focusing and reversed phase of the human serum proteome: optimization and protein database.

In biomarker discovery, the detection of proteins with low abundance in the serum proteome can be achieved by optimization of protein separation methods as well as selective depletion of the higher abundance proteins such as immunoglobins (e.g. IgG) and albumin. A relative newcomer to the proteomic separation arena is the commercial instrument PF2D from Beckman Coulter that separates proteins in the first dimension using chromatofocusing followed in line by reversed phase chromatography in the second dimension, thereby separating intact proteins based on pI and hydrophobicity. In this study, assessment and optimization of serum separation (undepleted serum and albumin-IgG-depleted serum) by the PF2D is presented. Protein databases were created for serum obtained from a healthy individual under traditional and optimized methods and under different sample preparation protocols. Separation of the doubly depleted serum using the PF2D with 20% isopropanol present in the first dimension running buffer allowed us to unambiguously identify 150 non-redundant serum proteins (excluding all immunoglobulin and albumin, a minimum of two peptide matches with acceptable Mascot score) in which 81 have not been identified previously in serum. Among them, numerous cellular proteins were identified to be specifically the skeletal muscle isoform, such as skeletal muscle fast twitch isoforms of troponin T, myosin alkali light chain 1, and sarcoplasmic/endoplasmic reticulum calcium ATPase. The detection of specific skeletal muscle protein isoforms in the serum from healthy individuals reflects the physiological turnover that occurs in skeletal muscle, which will have an impact on the ability to use generic "cellular" proteins as biomarkers without further characterization of the precise isoforms or post-translational modifications present.

Albumins↗
PubMed2001

Differences in the method by which plasma is separated from whole blood influences amphotericin B plasma recovery and distribution following amphotericin B lipid complex incubation within whole blood.

A previous investigation suggested that the use of plasma as the biological fluid for measurement of amphotericin B (AmpB) concentrations greatly underestimates the concentrations of AmpB in the total blood circulation following amphotericin B lipid complex (ABLC) administration to humans. The purpose of this study was to determine if differences in the method used to obtain plasma from whole blood influences the percentage of AmpB recovered in plasma following ABLC incubation in whole blood. ABLC (5 microg AmpB/ml; peak blood concentration observed in rabbits following intravenous bolus of ABLC at a dose of 1 mg/kg) was incubated in whole blood for 5 min at 25 degrees C. These conditions were used to mimic the sample retrieval conditions used when blood is obtained from animals and human patients. Following incubation, plasma was obtained from whole blood using five different methods: (A) Whole blood was centrifuged for 5 min at 23 degrees C, and the plasma was separated; (B) whole blood was stored at 4 degrees C for 18 h, and the plasma was separated by gravity; (C) whole blood was stored at 23 degrees C for 18h, and the plasma was separated by gravity; (D) whole blood was stored at 37 degrees C for 18 h in a water bath, and the plasma was separated by gravity; and (E) whole blood was stored at 30 degrees C for 18 h in a water bath, and the plasma was separated by gravity. All samples were protectedfrom light throughout the duration of the experiment. AmpB concentration in each plasma sample was determined by high-performance liquid chromatography (HPLC) using an external calibration curve. The whole blood:plasma Amp B concentration ratio and the percentage of AmpB partitioned into plasma following incubation of ABLC in whole blood for each plasma separation procedure was as follows: (A) 6.5:1 blood:plasma AmpB concentration ratio, 15.4% +/- 1.6% AmpB in plasma; (B) 2.98:1 blood:plasma AmpB concentration ratio, 33.6% +/- 7.7% AmpB in plasma; (C) 1.5:1 blood:plasma AmpB concentration ratio, 67.6% +/- 10.3% AmpB in plasma; (D) 1.5:1 blood : plasma concentration ratio, 68.1% +/- 1.1% AmpB in plasma; and (E) 1.2 : 1 blood:plasma AmpB concentration ratio; 83.4% +/- 5.5% AmpB in plasma. These findings suggest that when measurement of AmpB in plasma is required following ABLC administration, incubation of whole blood at 30 degrees C for 18 h appears to be the most effective method.

Amphotericin B↗
PubMed1982

Epidermal growth factor-induced centrosomal separation: mechanism and relationship to mitogenesis.

Using a rabbit antibody to MAP1 to stain centrosomes we have studied the mechanism by which epidermal growth factor (EGF) induces centrosomal separation in HeLa cells. The response is rapid, being detectable within 20 min after EGF (100 ng/ml) addition and by 4 h 40% of logarithmically growing cells and greater than 70% of cells synchronized at G1/S with 1 mM hydroxyurea show centrosomes separated by more than one diameter. A concentration of 0.05 ng/ml of EGF induces significant separation in synchronized cells (5-9% control vs. 20% with EGF at 0.05 ng/ml) and 0.1 to 0.5 ng/ml induces a half maximal response. Centrosomal separation is blocked by energy inhibitors, trifluoperazine, chlorpromazine, and W-7, cytochalasins B and D, and taxol, and is stimulated or enhanced by A23187, colchicine, and oncodazole. Trifluoperazine, W-7, cytochalasin D, and taxol also block DNA synthesis in response to EGF as measured by autoradiography using [3H]thymidine. Our hypothesis based upon these results is that EGF, by raising the free calcium level, activates calmodulin, which stimulates contraction of microfilaments attached to the centrosome, pulling the daughter centrosome apart. EGF may also induce depolymerization or detachment of microtubules in the vicinity of the centrosome which ordinarily serve to maintain its position and inhibit separation. Centrosomal separation may be a key event in triggering DNA synthesis in response to EGF and colchicine.

Calcium↗
PubMed2005

Separation of spinal cord motor signals using the FastICA method.

Evoked motor signals descending down the corticospinal tract can be recorded selectively with multi-contact electrodes from the spinal cord surface. This method of extracting motor signals from the spinal cord may provide a means of communication for people with spinal cord injury. The information rate obtained with such an interface will improve if the separation of neural channels can be increased. In this study, the feasibility of increasing the channel separation was investigated using the blind source separation (BSS) technique. Neural signals recorded with multi-contact surface electrodes were treated as a linear mixture of independent neural sources located inside the spinal cord. Principal component analysis (PCA) was applied to estimate the dimensionality of the raw signals, and then the fixed-point FastICA algorithm was used to separate the primary neural sources from the secondary (smaller) ones. In all trials but one, the separation between the neural channels has increased by eliminating the secondary sources. These results suggest that the information rate of a spinal cord interface can be improved by separating the neural recordings into their independent components and selecting the ones with the largest distance between them. Comparison of independent component analysis (ICA) and PCA reveals that ICA performs better in this application.

Action Potentials↗
PubMed2003

Separation of aliphatic and aromatic acids, aromatic sulfonates, quaternary ammonium compounds, and chelating agents on a reversed-phase column without ion pairing.

Cleaning products contain a wide variety of components. These include inorganic materials, weak acids, anionic surfactants, cationic surfactants, amphoteric compounds, and nonionic materials. The separation of these generally requires the use of multichromatographic modes. A system is developed that would give the maximum information for a cleaning product in a single chromatographic run. With the use of a hydrophobic, high-carbon-loading, and a relatively hydrophobic surface reversed-phase packing, such compounds as aromatic sulfonates, quaternary ammonium compounds, weak acids, nitrilotriacetic acid, ethylenediaminetetraacetic acid, and nonionic materials may be separated in a single run. The mode of separation is considered to be a combination of reversed-phase, ion-suppression reversed-phase, and adsorption chromatography. The separation is made on a YMC-Packl ODS-AQl column (4.6 x 250 mm, 120 angstroms). The separation employs a gradient run starting with 0.01 N H2SO4 for 10 min followed by a gradient for 15 min to 100% acetonitrile and continuing for an additional 5 min with 100% acetonitrile. The flow rate is 1 mL/min, and the separation is monitored at 210 nm.

Journal Article↗
PubMed2004

Effect of temperature on enantiomer separation of oxzepam and lorazepam by high-performance liquid chromatography on a beta-cyclodextrin derivatized bonded chiral stationary phase.

A reversed-phase high-performance liquid chromatography (HPLC) method with beta-cyclodextrin (beta-CD) derivatized as chiral stationary phase is used to directly separate oxazepam (Oxa) and lorazepam (Lor) enantiomers. The effect of temperature on the direct HPLC separation of Oxa and Lor enantiomers is studied for the commercially available beta-CD derivatized bonded chiral stationary phase. Chromatographic peak coalescence, appearing as a plateau between the resolved peaks, is observed at column temperatures of above 13 degrees C. Peak coalescence on the beta-CD derivatized bonded column is attributable to racemization of the Oxa enantiomer. By reducing the column temperature to 13 degrees C, the enantiomeric composition of Oxa and Lor could be determined on the chiral column. This method is expected to be useful for the resolution of 3-hydroxybenzodiazepines. At the same time, the separation mechanism is studied by calculating the thermodynamic parameters. The results reveal that the separation of Oxa and Lor enantiomer is a case of enthalpy-controlled separation, inclusion mechanism does not control the separation. The interaction between Oxa and beta-CD is an additionally strong pi-pi interaction or hydrogen bonding, but that between Lor or beta-CD derivatized is a weak pi-pi interaction or hydrogen bonding.

Anti-Anxiety Agents↗
PubMed1987

Sequence of centromere separation: a possible role for repetitive DNA.

The centromeres of a mitotic cell at the meta-anaphase junction separate in a non-random, genetically controlled sequence before anaphase migration ensues. In several, but not all, of the organisms studied so far it appears that the timing of separation of a centromere into two visible units depends upon the quantity of pericentric heterochromatin. A critical analysis of this parameter of cell cycle suggests that the sequence of centromere separation is influenced by repetitive DNA present in the pericentric region. In those cases with qualitatively uniform repetitive DNA in centromeric regions, the chromosomes carrying lesser quantities separate earlier than those with greater amounts. However, the overall pattern of separation may be determined by interactions between both quantitative and qualitative parameters of the repetitive DNA. It has been suggested that repetitive DNA has no transcriptional properties. It is probably only a structural component which acts as a site for the accumulation of protein molecules synthesized by some locus not present in the centromeric region. These proteins accumulate to saturate the centromeric repetitive DNA resulting in a (trilaminar) structure called the kinetochore. The longer the stretch to be saturated, the larger would be the kinetochore-like structure. Once saturated, the centromere splits into two subunits. Premature separation results in a lack of saturation and formation of an 'immature' kinetochore. This may lead to chromosome malsegregation. Thus, indirectly, one property of repetitive DNA in the centromeric region appears to be the maintenance of diploidy.

Anaphase↗