Method adjustment and equation set of maximum rainfall intensity, duration and frequency in the Mato Grosso do Sul State

Due to the lack of information concerning maximum rainfall equations for most locations in Mato Grosso do Sul State, the alternative for carrying out hydraulic work projects has been information from meteorological stations closest to the location in which the project is carried out. Alternative methods, such as 24 hours rain disaggregation method from rainfall data due to greater availability of stations and longer observations can work. Based on this approach, the objective of this study was to estimate maximum rainfall equations for Mato Grosso do Sul State by adjusting the 24 hours rain disaggregation method, depending on data obtained from rain gauge stations from Dourado and Campo Grande. For this purpose, data consisting of 105 rainfall stations were used, which are available in the ANA (Water Resources Management National Agency) database. Based on the results we concluded: the intense rainfall equations obtained by pluviogram analysis showed determination coefficient above 99%; and the performance of 24 hours rain disaggregation method was classified as excellent, based on relative average error WILMOTT concordance index (1982).

Detection of Pneumocystis in lungs of bats from Brazil by PCR amplification

Pneumocystis has been isolated from a wide range of unrelated mammalian hosts, including humans, domestic and wild animals. It has been demonstrated that the genome of Pneumocystis of one host differs markedly from that of other hosts. Also, variation in the chromosome and DNA sequence of Pneumocystis within a single host species has been observed. Since information about the occurrence and nature of infections in wild animals is still limited, the objective of this work was to detect the presence of Pneumocystis sp. in lungs of bats from two states from Brazil by Nested-PCR amplification. The bats, captured in caves and in urban areas, were obtained from the Program of Rabies Control of two States in Brazil, Mato Grosso and Rio Grande do Sul, located in the Mid-Western and Southern regions of the country, respectively. DNAs were extracted from 102 lung tissues and screened for Pneumocystis by nested PCR at the mtLSU rRNA gene and small subunit of mitochondrial ribosomal RNA (mtSSU rRNA). Gene amplification was performed using the mtLSU rRNA, the primer set pAZ102H - pAZ102E and pAZ102X - pAZY, and the mtSSU rRNA primer set pAZ102 10FRI - pAZ102 10R-RI and pAZ102 13RI - pAZ102 14RI. The most frequent bats were Tadarida brasiliensis (25), Desmodus rotundus (20), and Nyctinomops laticaudatus (19). Pneumocystis was more prevalent in the species Nyctinomops laticaudatus (26.3% = 5/19), Tadarida brasiliensis (24% = 6/25), and Desmodus rotundus (20% = 4/20). Besides these species, Pneumocystis also was detected in lungs from Molossus molossus (1/11, 9.1%), Artibeus fimbriatus (1/1, 100%), Sturnira lilium (1/3, 33.3%), Myotis levis (2/3, 66.7%)and Diphylla ecaudata (1/2, 50%). PCR products which could indicate the presence of Pneumocystis (21.56%) were identified in DNA samples obtained from 8 out of 16 classified species from both states (5 bats were not identified). This is the first report of detection of Pneumocystis in bats from Brazil.

Phenology, fruit set and dispersal of Cordia multispicata Cham., an important weed shrub of abandoned pastures in eastern Amazonia

ABSTRACT - (Phenology, fruit set and dispersal of Cordia multispicata Cham., an important weed shrub of abandoned pastures in eastern Amazonia). The reproductive ecology of the distylous tropical shrub Cordia multispicata was studied in an abandoned pasture in Paragominas County , Pará state, Brazil. It is a common species in the Amazon basin where it occurs as a weed in open and disturbed habitats. C. multispicata has many flowers per inflorescence (85 ± 12) but 84% abort before fertilization. Flowering occurs throughout the year. Fruits are small, with a red fleshy pericarp (skin-pulp) attractive to birds. Fruit set is lower during the dry season (less than 30%) and higher during the rainy season when there are many visits of insects to the flowers. Fruiting has a peak between the end of the dry season and the middle of the rainy season. Nineteen bird species were observed foraging for the fruits of C. multispicata, and 79% of those species can be considered as potential dispersal agents. The efficient seed dispersal and aggregated spatial distribution associated with some characteristics of the dispersors greatly contributed to the success of this species in abandoned pastures of eastern Amazonia.

Flowering phenology, seed set and arthropod guilds in Trichogoniopsis adenantha (DC) (Asteraceae) in south-east Brazil

and glades. This species blooms throughout the year, attracting arthropods of various guilds, including herbivores, pollinators and predators. In this study, done over a two year period, we described the phenology of T. adenantha and assessed the seasonal variation in arthropod numbers of different guilds. We also determined the periods of lowest and highest seed set. T. adenantha population showed a peak in flowering in March-April (rainy season) with greater production of achenes in December-April. April and October had respectively highest and lowest number of fertilized, undamaged ovules, and this pattern is possibly related with population dynamics of pollinators and herbivores. In August, which was the period of greatest damage to the stigma (by geometrid larvae), there was a positive relationship between the proportion of unfertilized ovules and flowers with damaged stigma, suggesting that floral herbivory may affect reproduction in T. adenantha. We discuss the complex dynamics of the beneficial and harmful interactions between arthropods and the host plant.

Pollination and fruit set in pumpkin (Cucurbita pepo) by honey bees

Species of Cucurbitaceae are cultivated worldwide and are depend on bee pollination for fruit set. Field and lab experiments were conducted at Cornell University, Ithaca, NY, during 1996 and 1997 to determine "Howden" pumpkin (Cucurbita pepo L.) pollen removal and deposition by honeybees and factors relating to male flower attractiveness. Several parameters were evaluated in flowers at anthesis: (1) removal of pollen from anthers by honey bees, (2) pollen deposition on the stigma by honey bees, (3) amount of pollen on the body of honey bees, (4) fruit set after bee pollination, and (5) male flower nectary's pores and flower attractiveness. Honey bees carried between 1,050 to 3,990 pollen grains and 13,765 were removed from an anther after one visit. The amount of pollen deposited on the stigma by the honey bees varied according to the number of visits, from 53 grains with one visit, to 1,253 grains with 12 visits, and the mean number of grains in each visit varied from 53 to 230 grains. The percentage of established fruits was higher (100%) when the flowers received 12 visits of Apis mellifera, corresponding to a load 1,253 pollen grains. The attractiveness of the male flower for pollen and nectar collection was increased by the degree of opening of the access pore to the nectary in the flower.

Occurrence of Akodon cursor (Rodentia, Cricetidae) with 14, 15 and 16 chromosome cytotypes in the same geographic area in Southern Brazil

The karyotype of Akodon cursor (initially identified as A. arviculoides) had been reported with chromosomal numbers 14 and 15 in the South and Southeast and 16 in Northeastern Brazil. We found the three cytotypes in a region of Southern Brazil. The G-band patterns of these specimens were the same as those from southeastern and northeastern regions. Seventeen different combinations of chromosomes due to a complex rearrangement in pair 1 and pericentric inversions in pairs 2 and 3 were identified. Seven of these combinations are new to in the literature.

Chromosome damage in underground coal miners: detection by conventional cytogenetic techniques and by submitting lymphocytes of unexposed individuals to plasma from at-risk groups

Chromosome abnormalities and the mitotic index in lymphocyte cultures and micronuclei in buccal mucosa cells were investigated in a sample of underground mineral coal miners from Southern Brazil. A decreased mitotic index, an excess of micronuclei and a higher frequency of chromosome abnormalities (fragments, polyploidy and overall chromosome alterations) were observed in the miners when compared to age-paired normal controls from the same area. An alternative assay for clastogenesis in occupational exposition was tested by submitting lymphocytes from non-exposed individuals to a pool of plasmas from the exposed population. This assay proved to be very convenient, as the lymphocytes obtained from the same individuals can be used as target as well as control cells. Also, it yielded a larger number of metaphases and of successful cultures than with common lymphocyte cultures from miners. A significantly higher frequency of chromatid gaps, fragments and overall alterations were observed when lymphocytes from control subjects were exposed to miner plasma pools. Control plasma pools did not significantly induce any type of chromosome alterations in the cultures of normal subjects, thus indicating that the results are not due to the effect of the addition of plasma pools per se.

TP53 mutations and loss of heterozygosity of chromosome 17 in colorectal tumors

The incidence of TP53 point mutations and loss of heterozygosity (LOH) of chromosome 17 in colorectal tumors was determined in a group of Brazilian patients. We screened DNA samples from tumors and distal normal mucosa of 39 patients with colorectal cancer, for TP53 mutations by PCR-SSCP (single-strand conformation polymorphism) analysis. Chromosome 17 LOH was investigated using six PCR-based polymorphic markers and one VNTR probe. TP53 mutations were demonstrated in 15/39 of the cases. Mutations were distributed among all exons examined (five to eight), the majority of them being G/C to A/T transitions. LOH of chromosome 17p and 17q was detected in 70 and 46% of the tumors, respectively. There was a significant association between TP53 mutations and LOH in chromosome 17p (P = 0.0035) and 17q (P = 0.03). Although no correlation was observed between TP53 genetic alterations and clinical/ pathological characteristics, the association of TP53 mutations with loss of both chromosome 17 arms may indicate that TP53 inactivation provokes an unstable phenotype in tumor cells in colorectal tumors.

Reading the human Y chromosome: the emerging DNA markers and human genetic history

Reading the human Y chromosome: the emerging DNA markers and human genetic history.

Chromosome polymorphism in Ctenomys minutus (Rodentia-Octodontidae)

A sample of 101 specimens of Ctenomys minutus was collected along its geographic range. Eight karyotypes (2n = 42, 45, 46a, 46b, 47, 48, 49 and 50) were found. The chromosome polymorphisms were due to Robertsonian rearrangements and tandem fusions. The distribution of polymorphisms indicated three population blocks: northern (2n = 49 and 50), central (2n = 46a, 47, and 48) and southern (2n = 42, 45, and 46b). These findings suggest that this species is undergoing a speciation process due to geographic isolation.

Recuperation and improvement of chromosome preparations stained with silver nitrate

Both periodic acid and photographic reagents have been used to remove the silver nitrate residues from cytological preparations. We used potassium ferricyanide to remove AgNO3 salts in cases of excessive chromosome impregnation. This method produced partial decolorization, with contrast enhancement. Counterstaining with Giemsa also promoted a better contrast between chromosome arms and NORs, which were preserved and retained a dark color. Application of this procedure to chromosome preparations treated sequentially for CBG banding/AgNO3 staining promoted complete decolorization of C+ regions, leading to "reverse" C-banding, generally with high contrast.

Chromosome number in germplasm accessions of Paspalum notatum (Gramineae)

Chromosome numbers are reported for 127 germplasm accessions of Paspalum notatum maintained by EMBRAPA (Empresa Brasileira de Pesquisa Agropecuária) in two research centers in Brazil. Most accessions were collected in their natural habitats in Southern Brazil. Tetraploidy (2n = 40 chromosomes) was predominant (91% of the accessions studied), confirming previous reports for the species. Eleven accessions with 2n = 20 chromosomes, although collected in the wild, are possibly derived from 'Pensacola' bahiagrass, commonly cultivated in the area since its introduction from the United States in the 60's, for the establishment of permanent pastures.

Chromosome sensitivity to bleomycin in G2 lymphocytes from Down syndrome patients

Several studies have demonstrated that lymphocytes from patients with Down syndrome (DS) exhibit an increased frequency of chromosome aberrations when they are exposed to ionizing radiation or to chemicals at the G0 or G1 phases of the cell cycle, but not at G2, when compared to normal subjects. To determine the susceptibility of DS lymphocytes at G2 phase, bleomycin, a radiomimetic agent, was used to induce DNA breaks in blood cultures from 24 Down syndrome patients. All the patients with DS showed free trisomy 21 (47,XX + 21 or 47,XY + 21). Individuals that showed an average number of chromatid breaks per cell higher than 0.8 were considered sensitive to the drug. No control child showed susceptibility to bleomycin, and among the 24 patients with DS, only one was sensitive to the drug. No significant difference was observed between the two groups, regarding chromatid break frequencies in treated G2 lymphocytes. The distribution of bleomycin-induced breaks in each group of chromosomes was similar for DS and controls. No significant difference was found in the response to bleomycin between male and female subjects. Probably, the main factor involved in chromosome sensitivity of lymphocytes from patients with DS is the phase of the cell cycle in which the cell is treated.

Family names and the length of the Y chromosome in Brazilian blacks

The variability of the lengths of the heterochromatic and euchromatic segments of the human Y chromosome was studied by a quantitative method of densitometric measurement in 60 normal and unrelated black individuals (30 with and 30 without devotional surnames), living in Salvador, Bahia, northeastern Brazil. Thirty normal and unrelated Caucasian individuals of European origin, living in Curitiba, Paraná, south Brazil, were included as controls. The heterochromatic segment and total Y chromosome lengths were greater in caucasians than in blacks without devotional surnames, and these were greater than in blacks with devotional surnames. These findings are in agreement with previous reports of a higher percentage of black ancestry in blacks carrying devotional surnames than those carrying non-devotional ones.