Cytogenetic, morphometry and RAPD analyses were performed on trees of wild and cultivated olives in Iran. For morphometric analysis 20 morphological characters based on International Olive Council descriptors, including 6 quantitative and 14 qualitative characters, were studied. Clustering and ordination plots showed the presence of 2 wild olive forms (subspecies) in Iran which were identified as Olea europaea subsp. cuspidata and Olea europaea subsp. ferruginae. Cytogenetic study of O. europaea subsp. cuspidata showed presence of 2n=46 chromosome number and normal bivalent formation as well as chromosome segregation. Wild olives were separated from cultivated cultivars in clustering and ordination plots both in morphological and cytogenetical characteristics studied. RAPD analysis showed genetic differences of the 2 subspecies identified, revealing the occurrence of specific loci in each subsp. O. europaea subsp. cuspidata showed a relatively higher level of intra-population genetic diversity compared to that of O. europaea subsp. ferruginae. This is the first report of wild olives in Iran.
A novel polymorphism of nucleolar organizer regions (NORs) and complex inversion chromosome 8 of the white-handed gibbon (Hylobates lar) in Thailand was found after standard whole blood lymphocyte culture and G-banding technique were applied to stain the chromosomes. The results showed that 2n of H. lar was 44. The type of autosomes were 28 metacentric, 12 submetacentric and 2 acrocentric chromosomes, with the X and Y-chromosome being submetacentric and acrocentric chromosome, respectively. In addition, a pair of the long arm of chromosome 13 showed clearly observable NORs. This is the first report on polymorphism of NORs in H. lar. The result indicated the presence of heteromorphism of chromosome 13 (13a13b) in female; NORs were found in 13a and not in 13b. There is homomorphism of chromosome 13 (13a13a) in male, there are NORs in both chromosomes. We also found the complex inversion chromosome 8 that presence homomorphism (8b8b) in both male and female.
The present paper reports a case of spontaneous occurrence of an abnormal spindle behaviour during male meiosis in the tetraploid (2n=28) cytotype of Papaver dubium from the cold regions of India. In the affected accessions, meiotic course is perfectly normal up to MI resulting into normal oriented 14 bivalents. But during AI/TI and AII/TII spindle activity is abnormal resulting into variable number of laggards, chromatin bridges, unoriented chromosomes, micronuclei, tetrads with microcytes, and polyads. Examination of 1280 PMCs during microsporogenesis reveal that 13.28% tetrads were abnormal resulting into some pollen sterility (6.76%) and variable sized apparently fertile pollen grains. Although the cytological status of these apparently fertile pollen grains could not be ascertained but there role in producing variants in the species can not be ruled out.
We report an efficient protocol for in vitro direct plant regeneration via multiple shoot induction in Stylosanthes seabrana. Stylosanthes is an important range legume for humid to semi-arid tropics. It is very good fodder for animals, containing about 15% crude protein with 61% in vitro dry matter digestibility. S. seabrana, in particular, is rich in lysine and sulphur-containing amino acids, which are limiting amino acids in ruminants' feed. Limited genetic variability in the germplasm and susceptibility to anthracnose disease are major challenges in Stylosanthes improvement. S. seabrana, being a self-pollinated and diploid species, has been identified as a candidate species for improvement through genetic transformation. In vitro plant regeneration is one of the pre-requisites for development of transgenic Stylosanthes with desirable traits. In the present study, we used apical meristematic axis from in vitro grown seedlings as explant for multiple shoot induction. MS medium supplemented with BAP, Kn and TDZ, in different concentrations and combinations, were used for apical meristem culture. Best response, in terms of the number of shoots (4) per apical meristem, was observed on MS medium supplemented with 3.0 mg/l BAP. Shoot elongation was achieved on MS medium containing 2.0 mg/l GA and best rooting was induced on MS medium supplemented with 2.0 mg/l IAA. Tissue cultured plants showed normal growth, flowering and seed setting. To the best of our knowledge, this is the first report on plant regeneration via multiple shoot induction in S. seabrana. A standardized protocol would be very useful for Agrobacterium-mediated genetic transformation of Stylosanthes with the gene(s) of interest.
Mitochondrial DNA (mtDNA) is highly organized into a compact structure, the mitochondrial nucleoid (mt-nucleoid). To facilitate our understanding of the regulation of mtDNA genetic activity within the mt-nucleoid structure, we have identified a novel mt-nucleoid protein Pmn34 (Physarum polycephalummitochondrial nucleoid protein 34), having a molecular weight of 34 kDa, from pure mt-nucleoids isolated from the true slime mold, Physarum polycephalum. The Pmn34 protein is composed of 326 amino acids with mitochondrial transit peptides and its primary sequence contains a conserved 3′ to 5′ exonuclease motif of the “DEDD” superfamily. DNA mobility shift assays demonstrated that recombinant Pmn34 binds weakly to both mtDNA and λDNA with no apparent sequence specificity. Furthermore, immunoblotting and immunostaining analyses revealed that Pmn34 localizes specifically in the peripheral region of mt-nucleoids. These results indicate that Pmn34 functions in the peripheral region of mt-nucleoids, suggesting that the mt-nucleoid is compartmentalized into functional domains.
Cell fusion sites of the gametes relative to the flagella and eyespot occupy different positions between the opposite mating types in several green algae. This phenomenon has been found by light microscopy in Chlamydomonas reinhardtii and later confirmed by a computer-aided 3D-reconstruction of serial sections viewed with transmission electron microscopy (TEM). In this study, we determined this spatial relationship in the gametes and planozygotes of C. reinhardtii using field emission scanning electron microscopy (FE-SEM). This technique is very easy, straightforward, and enables the observation of numerous cells with high resolution comparable to TEM. In addition to flagella and fertilization tubules, FE-SEM visualized the eyespot and their lipid globules that has not been detected in C. reinhardtii gametes using conventional SEM. Using the eyespot as a positional marker, it was shown that mt− gamete fusion site is located on the same side of the plane bisecting the flagellar beat as the eyespot whereas the mt+ site is located in the opposite position. After cell fusion, 2 eyespots aligned on the same side of the quadriflagellate planozygote. The 2 no. 1 and 2 no. 2 flagella each from the mt+ and mt− gamete became a pair and pointed to the same direction. These results are consistent with the previous observations. Therefore, it is suggested that FE-SEM is an ideal technique for the visualization of topographical images of the flagella-eyespots-cell fusion sites in the mating gametes and planozygotes in C. reinhardtii.
Cefotaxime is a semisynthetic broad-spectrum bactericidal antibiotic derived from cephalosporin C. The aim of this work is to evaluate the genotoxic effect induced by intraperitoneal (i.p.) administration of cefotaxime at different doses (260, 520 and 1040 mg/kg b.wt.). The induction of sister chromatid exchanges “SCE's” in mouse bone marrow cells, chromosomal aberrations in mouse primary spermatocytes after repeated treatment (4, 7 and 10 d), and morphological sperm abnormalities were determined. The 3 tested doses of cefotaxime induced significant increase in the frequency of sister chromatid exchanges with dose-dependent relationship. A significant increase in the percentage of structural and numerical chromosomal aberrations in mouse spermatocytes was observed after treatment with the doses 520 and 1040 mg/kg b.wt. Cefotaxime also induced different types of head and tail sperm abnormalities. The results showed that cefotaxime has clastogenic and aneugenic effect.
Robertsonian translocation (centric fusion) has been well documented in domestic cattle, with the most commonly occurring fusion involving chromosomes 1 and 29. Fifty conventional staining, G-banding, C-banding and NOR-banding metaphase spreads derived from lymphocyte cultures were analyzed for each animal. The Thai banteng has diploid chromosome number of 2n=57 in males and females instead of the normal 2n=60. The chromosomes presence of an extra acrocentric chromosome and 2 submetacentric chromosome while the loss of 6 telocentric chromosomes was observed [57, rob(1/29)(4/28)]. Results from G-banding analysis confirm that 6 autosomes involved in the translocation are bovine homologues 1/29 and 4/28. This is the first report on polymorphism of nucleolar organizer regions (NORs) of Thai banteng. It indicated the presence of heteromorphism of telocentric chromosomes in both male and female, there are NORs in 1 telocentric chromosome but it dose not exist in another telocentric chromosome.
Karyotype study was performed in 23 populations of nine Silene species belonging to the section Sclerocalycinae growing in Iran. The species studied were diploid (2n=2x=24) and tetraploid (2n=4x=48). The highest value of total and mean haploid chromosome length occurred in the Kerman 2 population of S. stapfii, while the lowest value of the same parameters occurred in the Kerman population of S. shahrudensis. ANOVA and LSD tests showed a significant difference for total size of the chromosomes and size of the short and long arms among the species studied, indicating the role of quantitative genomic changes in the Silene species diversification. A positive significant correlation was observed between total chromosome length, mean chromosome length, size of the longest chromosome, size of the shortest chromosome and A1 index of Romero-Zarco, while total chromosome length showed negative significant correlation with TF%, indicating that lower values of total chromosome length occur in the species having more symmetrical karyotypes (higher TF%), while higher values occur in asymmetric karyotypes (higher A1 values). The species studied differed in their karyotype formulae, indicating the occurrence of structural changes in their chromosomes
Chromosome counts of 6 populations of 4 species in the genus Artemisia from the family Asteraceae are reported. All taxa were collected from west provinces of Iran. Three species, Artemisia fragrance, A. spicigera and A. scoparia, were not accordance with previous counts. The most of studied taxa had the basic number x=9 with ploidy levels ranging from 2x to 8x, but A. incana had x=8. Both diploidy and triploidy were found for A. incana that can be regarded as the sign of new species generation. This is the first report for ploidy level 2n=8x=72 for A. spicigera.
Organellar DNA in mitochondria and plastids are organized with proteins into a compact structure known as the nucleoid. As the nucleoid is supposed to be the unit of inheritance for the organellar genome, it is important to understand its cytological behavior. Like plants, malaria parasites carry two organelles, the mitochondrion and the apicoplast–a non-photosynthetic plastid. However, probably because of the small size of the genome in each, visualizing the nucleoid in the Plasmodium organelles by regularly-used fluorescent dye such as DAPI, has been difficult. Here, we developed new, effective methods to visualize the organellar nucleoid in the human malaria parasite Plasmodium falciparum. With our methods using SYBR Green I or PicoGreen, nucleoids were observed in ring-stage parasites. Analyzing transfectant parasites carrying a DsRed-labelled organelle, we concluded that the parasite's mitochondrion has 1 nucleoid which is visualized with our methods. The parasite has a second nucleoid in the apicoplast, but higher concentration of the dye was required to visualize it. Our new methods would be useful for further cytological analysis of the nucleoids in the mitochondrion and the apicoplast of the malaria parasite.
The ploidy level of Cyclamen rohlfsianum was analyzed through the measurement of the relative fluorescent intensity (RFI) of nuclei stained with 6-diamidino-2-phenylindole (DAPI) using flow cytometry (FCM), and through the observation of mitotic and meiotic chromosomes, as compared with those of C. persicum (2n=2x=48, Cpe2x), C. rohlfsianum (Cro2, 2n=96), C. purpurascens (2n=2x=34, Cpu3) and a hybrid (2n=65) of C. rohlfsianum (Cro2, 2n=96)×C. purpurascens (2n=2x=34, Cpu3). The mean chromosome pairing at diakinesis and/or metaphase I of PMCs in Cro2, Cpu3 and their hybrid was 0.65I+47.07II+0.03III+0.28IV, 0.16I+16.92II and 17.00I+24.00II, respectively. These findings suggest that Cro2 is an autotetraploid (2n=4x=96) and the Cro2×Cpu3 hybrid is an allotriploid (2n=3x=65), produced by crossing an autotetraploid and diploid. The chromosome number of Cro3 was 2n=144, equal to 1.5 times that of Cro2 (2n=4x=96) and the DNA content of Cro3 estimated by the RFI value corresponded to approximately 1.5 times that of Cro2, suggesting that Cro3 is an autohexaploid (2n=6x=144). Twelve C. rohlfsianum plants of uncertain chromosome number were classified into 3 autotetraploids and 9 autohexaploids by FCM analysis, suggesting intraspecific differentiation concerning the ploidy level in C. rohlfsianum.
The chromosomal positions of 5S and 25S rRNA genes, as well as of DAPI (4′,6-diamidino-2-phenylindole) bands are described for 5 Vicia species (Vicia macrocarpa, Vicia sativa, Vicia narbonensis, Vicia ervilia and Vicia faba) to find out the phylogenetic relationships among studied species. From the results, it was concluded that the phylogenetic relationships among the studied species are as follows: Vicia ervilia is closely related to Vicia narbonensis and Vicia narbonensis is related to Vicia macrocarpa. However, the degree of relation between Vicia narbonensis, and Vicia macrocarpa is less than the relation between Vicia narbonensis and Vicia ervilia, while Vicia sativa is closely related to Vicia macrocarpa, but Vicia faba is far from all studied species.
Two F1 hybrids namely TIA and PARROT and an open pollinated cultivar viz. TAJ-88 of Momordica charantia L. (bitter gourd) were cytogenetically investigated. The 3 cultivars were found to possess 2n=22 metacentric chromosomes. However, a plant specimen of cultivar TIA had 2n=44 chromosomes. The extreme symmetric karyotypes revealed these cultivars as primitive. Three CMA positive bands were found in TIA and PARROT whereas 4 were found in TAJ-88. On the other hand, a plant specimen of TIA had 6 CMA positive bands. The distribution, location and intensity of CMA positive bands were different among the 3 cultivars. A number of DAPI positive bands were found in TIA and PARROT. It was possible to identify some marker chromosomes with CMA and DAPI staining specific to each cultivar. Fluorescent banding indicated the occurrence of minute deletion and paracentric inversion in the genomes of these cultivars. The overall karyotypic features revealed that a plant specimen of cultivar TIA was actually an auto-tetraploid. With the help of fluorescent banding, the karyotype diversity among these 3 cultivars was determined.