Infusions and concoctions of Ilex paraguariensis are used as medicinal, nutritional and stimulant beverages in southern South America. Crop production is about 300,000 tons/year in Argentina, where the consumption rate reaches 5–9 kg/capita/year. In this study, we assessed the cytotoxicity of aqueous extracts of I. paraguariensis in the Allium test and Artemia salina microwell test. The extracts were prepared from commercial and “home processed” (laboratory) and were tested at concentrations of 5–40 g/l. Both extracts significantly decreased root growth and the mitotic index (MI). These effects were greater for the commercial material for which concentrations ≥10 g/l virtually abolished mitosis. The disturbance of mitotic behaviour was significant at 5–10 g/l of the “home-processed” product and included c-mitotic phenomena (over-condensed and disorganized metaphases, sticky metaphases, arrested anaphases, binucleated interphases) which could contribute to the increase in metaphase and anaphase indexes. None of the extracts were cytotoxic in the Artemia salina test. It is concluded that the Allium test is adequate for a preliminary screening of genotoxicity of medicinal plants and that genotoxic effects can be increased by the commercial manipulation of the raw product.
Cytological effects of some (Pb, Cu, Zn, Hg) heavy metals were tested on meiotic studies of Helianthus annuus. The used heavy metals did not show much variations in the type of induced abnormal PMCs. The abundant meiotic irregularities stickiness, lagging, bridges, unequal separation, fragmentation etc. were observed. Mercury was the most toxic of all used heavy metals since it produced highest percentage of abnormal PMCs. Lead nitrate is a mutagen which induce tetraploidy.
Random amplified polymorphic DNA (RAPD) markers were used to study the genetic relationships among 10 species belonging to 2 sections of the genus Dalbergia. Of the 20 primers initially screened for polymorphism, only 10 amplified genomic DNA across all the 10 species. A total of 224 RAPD bands were observed with an average of 22.4 bands per primer, of which 99% were polymorphic. Pair wise genetic distances were calculated between species according to Jaccard, then used to construct UPGMA dendrogram. Cluster analysis based on the genetic similarities placed 10 species of Dalbergia in 2 clusters, with D. latifolia, D. sissoides, D. horrida and D. melanoxylon in Cluster A, and D. lanceolaria, D. paniculata, D. volubilis, D. rubiginosa, D. malabarica and D. sissoo in cluster B. These 2 clusters corresponds to sections: Sissoa and Dalbergia respectively. The results show that D. paniculata is very closely related to D. lanceolaria and suggested that D. paniculata can be considered as a subspecies of D. lanceolaria. The results of the present investigation distinguished the D. sissoides from D. latifolia, which was considered as a variety of D. latifolia. RAPD data supports the independent species status of the 2 species. The relationship between other species of Dalbergia in each cluster is discussed. This is the first report on genetic relationships among some species of Dalbergia using PCR based DNA markers.
Genomic DNA from 6 representative individuals of Acanthus ilicifolius from 6 mangrove ecotypes of north-easten India was analyzed for RAPDs using 10 primers. A total of 158 amplification products were observed with an average 15.8 amplicons per primer out of which 51.89% were polymorphic. The polymorphic RAPDs were pooled and clustering was carried out based on mean similarities for individual populations. The dendogram showed group of ecotypes, which are near to each other into specific clusters. These results demonstrated that considerable inter-ecotype genetic variation exists in A. ilicifolius and this lack of genetic variation is not the reason for the morphological uniformity observed across the range of the species. At the inter-ecotype level ∼17 of RAPD loci (56.66%) detected through the use of 10 primers. The somatic cells of the species displayed 44 chromosomes, with no numerical changes at inter-ecotype levels with few alterations in chromosome type. The genome size further added a significant variability in the context of inter-ecotype divergence.
In the present study, 30 seeds of Vicia faba (2n=12) treated with 0.005% colchicine for 8 h produced 15 polyploids. The success of induction of polyploidy by this method was 50%, which is very high as compared to any other methods used so far in this species. Presoaking the seeds in distilled water for ∼20 h proved more effective in inducing the polyploidy. Typical polyploid characters like gigantism, bigger leaves, flowers and pods etc. were exhibited by the induced colchitetraploids, however, they had reduced pollen fertility and number of seeds/pod and plant as compared to diploids. Polyploidy was confirmed by chromosome counts (2n=4x=24) at meiosis as well as at root tip mitosis. The method is easy and reliable for successful induction of polyploidy with colchicine in this species. We also recommend this method for induction of polyploids in other leguminous crops.
Oxalis corniculata var. atropurpurea Planch. reported from Malaysia is a shade preferring variety of the cosmopolitan weed, O. corniculata. Differences in karyotype and in floral and vegetative morphology along with the strong post-pollination reproductive barriers suggest that the variety atropurpurea merits consideration for species status.
An X1X2Y sex chromosome system is reported for the first time in Gymnotus sp. The chromosome number observed was 2n=40 (14 M-SM+26 ST-A) in females and 2n=39 (15 M-SM+24 ST-A) in males, with the same fundamental number in both sexes (FN=54). The multiple sex chromosome system might have been originated by a Robertsonian translocation of an ancestral acrocentric Y-chromosome with an acrocentric autosome, resulting in a metacentric neo-Y chromosome observed in males. Single NORs were detected on the short arm of a middle-sized acrocentric chromosome pair. Constitutive heterochromatin was observed in the pericentromeric regions of several chromosome pairs, including the neo-Y chromosome and the NOR carrier chromosomes. The DAPI/CMA3 stain revealed that all the pericentromeric heterochromatin are A+T rich whereas the NORs were associated with G+C rich base composition. The possible ancestral condition characterized by an undifferentiated Y- chromosome from all the Gymnotiformes fishes is discussed.
The chromosome number of 25 Bromeliaceae species from the genera Dyckia, Vriesea, Aechmea, Ananas, Billbergia, Nidularium, Neoregelia, Neoglaziovia, Orthophytum, Portea, Quesnelia and Wittrockia were assessed. All are diploid 2n=50, except for Orthophytum albopictum and Neoglaziovia variegata, both tetraploids, 2n=100. The chromosome counts are the first report for 19 of the 25 species evaluated. All chromosome counts reinforce x=25 as the basic number for the family.
The non-banded and C-banded karyotypes of 10 species of South Indian short horned grasshoppers of the family Acrididae with diploid number 23 in males and 24 in females were studied. All the species except Dociostaurus species A. and Leva indica have shown telocentric chromosomes. Interspecific non-banded and banded karyotypic comparison and its evolutionary implications are discussed.
In the present study, fluorescence in situ hybridization (FISH) was employed to determine the chromosomal location of genes 18S rDNA and 5S rDNA in four rainbow trout stocks. In specimens from the stocks of Núcleo Experimental de Salmonicultura de Campos do Jordão and Gavião river, 18S genes were located at a subterminal position in the long arms of two submetacentric chromosomes, whereas in specimens from stocks of Mount Shasta and Teresópolis they were found in the short arms. In all analyzed stocks, 5S genes were located in two chromosome pairs. In a subtelocentric pair, 5S genes were present in the short arms and, in the other submetacentric pair, 5S genes were at an interstitial position. In the latter, 18S and 5S genes were contiguous. Taking into account that both 18S and 5S rDNA genes have been localized in the short arm of a submetacentric chromosome in almost all rainbow trout samples so far studied, the presence of such genes in the long arm, as seen in the samples from Núcleo Experimental de Salmonicultura de Campos do Jordão and Gavião river, supports the hypothesis of a pericentric inversion involving this chromosome segment in the ancestor line of these stocks. The observed polymorphism allowed the identification of a very useful genomic marker, and may therefore constitute an important tool in the genetic management of rainbow trout stocks.
Different cytogenetic techniques were used to analyze the chromosomes of Characidium gomesi with the main objective of comparing the base composition of ZZ/ZW sex-chromosomes, B-chromosomes and the heterochromatin of A-chromosomes. The results of digestion of chromosomes with AluI restriction endonuclease (RE), silver and CMA3 staining, C-banding and fluorescence in situ hybridization (FISH) with the 18S rDNA probe suggested the existence of compositional differences between the heterochromatin of ZZ/ZW sex-chromosomes, A- and B-chromosomes, and indicated the presence of different numbers and morphology of B-chromosomes in the samples of this population.
The present work was conducted to evaluate the effects of Tributilin (TBT) on chromosomes of the Neotropical fish Astyanax sp. Twenty nine individual fishes (8 females and 21males) were divided into two groups. Within 15 fishes in one group, 7 fishes were treated with TBT for 19 d, while other 8 fishes were without, and were sacrificed for the observation. Another 14 fishes (8 for treatment, and 6 as control) were treated for 37d. Chromosomal aberration was detected in both group of treated and of non-treated fishes. However, the frequency of aberration of chromosome was significantry higher in the treated fishes. These data represent the first evidence of the effects of TBT on chromosomes of a Neotropical fish species.
Morphology was characterized among 40 samples of Broussonetia papyrifera Vent. from 40 areas in 10 provinces of Thailand. Meiotic behavior from pollen mother cells was prepared using the standard aceto-orcein staining technique. The somatic prometaphase chromosomes were splashed on glass slides and stained with Giemsa solution. According to meiosis and mitosis, all samples were diploid. Chromosome length and condensation pattern (CP) were analysed using the CHIAS III software. An idiogram based on CP was generated which is the first reported idiogram of paper mulberry.
Flagellar movement and mating behavior of the biflagellate gametes of the marine green alga, Ulva arasakii was studied using high-speed video microscopy to clarify the rapid fertilization process of marine green algae. Discharged male and female gametes always swing their flagella backward during forward swimming. The beat pattern is flagellar beat with undulatory waves produced at the flagellar base being propagated toward the tip. One beat cycle takes 15 ms in both male and female gametes. When the male gamete encountered the female gamete, initial contact between the two gametes took place at one flagellar tip and at the anterior end of the cell body. Although attachment and detachment of flagellar tips occurred during the fertilization process, the male gamete kept in contact with the female gamete. Then male and female gametes adhered respectively at the anterior side of the cell body and at the flagellar tips. Nevertheless, they continued to move their flagella with a flagellar beat and oscillated their cell bodies. Finally, the gamete pair lay side by side with their longitudinal axes nearly parallel to one another within 30–100 ms after initial contact of the two gametes.
Two F1 hybrids one between wild C. annuum var glabrisculum and C. frutescens (H1) and another between wild C. annuum var antigua and C. frutescens (H2) were obtained. Cytogenetic analysis of F1 hybrids showed that the parental genomes differ from each other by 2 or 1 translocations, 1 inversion and some minor structural alterations leading to reduced homologies between the respective parental genomes. Meiotic irregularities pollen and seed sterilities were higher in H2 than in H1. Probable reasons for the differences in respect of their crossability relationships, chromosome pairing and fertilities in non-rearing of reciprocal hybrids are suggested. The role of chromosome structural changes in genome differentiation is suggested. Isolating mechanisms viz., hybrid inviability and hybrid weakness in the reciprocal cross and hybrid sterility in the F1 hybrids are in operation.
Meiotic studies of A. chiquitana, A. matiensis, A. subcoriacea (Sect. Procumbentes), A. triseminata (Sect. Triseminatae), A. benensis, A. diogoi, A. herzogii and A. kempff-mercadoi (Sect. Arachis) are reported for the first time. Meiotic behaviour was essentially regular in most of the species, with 10 II at diakinesis-metaphase I, except in A. benensis which presented 8 II+1 IV in 2% of the pollen mother cells. Most of the bivalents were of the ring type, and only one or two bivalents were usually of the rod type. Chiasmata were always located in distal to terminal position even at diplotene and diakinesis. Normal segregation of bivalents is in accordance with the recorded high meiotic indexes and pollen stainability. Only one pair of chromosomes was easily recognized, that being the very small “A” pair in the species with A genome of Arachis section. This small pair can be used at meiosis to distinguish between the A and B genomes species and may be a useful marker to detect allopolyploids involving both genomes.
Method of rooting in petioles was developed for leaves of Arachis plants. The objective was the development of methodology that allows the chromosome number determination for evaluation of the ploidy level in colchicine-treated branches. In order to obtain a high frequency of metaphases and chromosomes with clear morphology, roots were pretreated with 8-hydroxyquinoline combined to cycloheximide for 2 h. Root tips were stained using Feulgen dye for chromosome analysis. This method can be applied also for cytological studies of materials in which seeds are not available or cutting is not feasible.
Chromosome numbers of 7 species belonging to Polytrichum, Pogonatum and Atrichum in Polytrichaceae were studied. Except in Atrichum undulatum, the chromosome number was n=7. A. undulatum was proved to be triploid with n=21.
Insect mandibular glands are always associated to the mandibles; they are part of the salivary glandular system. The mandibular glands are composed by a reservoir associated to the secretory cells, with each secretory cell connected to the reservoir by means of individual canaliculi. These glands play an important role in the production of pheromones, which are compounds involved in defense, communication, and reproduction of the colony. Mandibular glands of soldiers and major and minor workers of the ant Atta sexdens rubropilosa were processed for different histochemical tests, total protein content, and protein electrophoretic profile determination. The histochemical tests detected the presence of lipids, DNA/RNA, polysaccharides, and proteins at different regions of the gland. The protein electrophoretic profiles showed that the total protein content as well as the number of peptides of each caste follow a progressive order in relation to the size of the individual. Thus, we suggest that the production of secretion is directly linked to the task that the individual performs in the colony.
A part of chromosome 5 from Arabidopsis thaliana, which has 36 genes, on yeast artificial chromosome (YAC) was transferred into tobacco BY-2 cells using a bio-active beads method. The YAC was constructed using the chromosome-splitting technique. The GFP gene located on the YAC showed repeated transient expression after transformation. Molecular analyses confirmed that 1 (At5g57980) of the 5 genes checked had transcribed in the tobacco BY-2 cells. This demonstrates that the promoter of this gene could work in both A. thaliana and tobacco BY-2 cells.