The quantity of blood ingested by various species of fleas in an experiment

Data are given on the blood amount engorged by the fleas Xenopsylla conformis, X. cheopis, Leptopsylla segnis, Nosopsyllus laeviceps, N. consimilis, Ctenophthalmus golovi, Neopsylla setosa, Citellophilus tesquorum and Coptopsylla lamellifer. The average weight of blood portion in females of different species engorged for the first time ranged from 0.05 mg (X. conformis) to 0.72 mg (C. lamellifer). Females of most species, which had multiple blood meals, engorge more blood. Males engorge less blood than females and blood portions do not increase with age. In all sex-age groups most ectoparasites cease feeding spontaneously after having incomplete blood meal. Indices are suggested for the estimation of saturation rate in fleas during feeding.     

Seroprevalence and risk factors associated to Mycobacterium bovis in wild artiodactyl species from southern Spain, 2006-2010

The control of bovine tuberculosis (bTB) is at a critical point in the last stage of eradication in livestock. Wildlife species recently have emerged infected with TB in Europe, particularly ungulates in the Iberian Peninsula. Epidemiological information regarding TB in wild ungulates including affected species, prevalence, associated risk factors and appropriate diagnostic methods need to be obtained in these countries. A cross-sectional study was carried out on wild artiodactyl species, including Eurasian wild boar (Sus scrofa) red deer (Cervus elaphus), roe deer (Capraelus capraelus), fallow deer (Dama dama), Spanish ibex (Capra pyrenaica hispanica) and mouflon (Ovis musimon), in Spain to assess the seroprevalence against Mycobacterium bovis or cross-reacting members of the Mycobcaterium tuberculosis complex (MTBC), and to provide information on associated risk factors. Previously, two in-house indirect enzyme linked immunosorbent assays (bPPD-ELISA and MPB83-ELISA) were developed using known TB status sera. Positive reference sera were selected from infected animals confirmed by culture. The M. bovis isolates belonged to spoligotypes SB0121, SB0120, SB0295, SB0265 and SB0134. Two hundred and two out of 1367 (7.5%; 95% CI: 6.1-8.9) animals presented antibodies against M. bovis by both bPPD-ELISA and MPB83-ELISA. Significantly higher TB seroprevalence was observed in wild boar compared to the other species analyzed. Interestingly, seropositivity against M. bovis was not found in any out of 460 Spanish ibex analyzed. The logistic regression model for wild boar indicated that the seropositivity to M. bovis was associated with age, location and year of sampling, while the only risk factor associated with M. bovis seroprevalence in red deer and fallow deer was the age. The seroprevalence observed indicates a widespread exposure to MTBC in several wild artiodactyl species in southern Spain, which may have important implications not only for conservation but also for animal and public health.     

The distribution frequency of Candida species in the genitourinary tract among symptomatic individuals in Nigerian cities

A clinical survey was carried out in seven cities in the southern part of Nigeria to determine the relative distribution of genitourinary Candida species in symptomatic patients reporting for diagnosis and treatment. Seven Candida species were identified using the CHROMagar Candida method and the API 20C System. Candida species were represented by Candida glabrata (33.7%), Candida albicans (20.1%), Candida tropicalis (18%), Candida guilliermondii (17.8%) Candida pseudotropicalis (5%), Candida parapsilosis (5%), and C. albicans var.stellatoidea (1.2%). The distribution of these species among the various age groups (15-20, 21-25, 26-30, 31-35, 36-40 and 41 plus years) was statistically insignificant. Out of the 517 positive samples, 182 (35%) were found in the age group 26-30 years, while age 41 plus had the lowest frequency (1.2%). The results presented show that C. albicans, usually reported to be the most frequently isolated species, is not the main species in the cities studied. With C. glabrata in preponderance, the finding supports recent studies reporting that several pathogenic non-C. albicans species are now being frequently isolated. The level of social activities, such as drug abuse and sexual promiscuity, may be important in the distribution frequency of Candida species in different age groups and locations.     

A measure of species diversity related to the lognormal distribution of individuals among species

An investigation has been made of the relation between species diversity and the lognormal distribution of individuals among species, using phytoplankton samples from the Indian Ocean. The area under the truncated lognormal curve representing a sample gives the total number of species, S, while the logarithmic standard deviation, σ, gives a measure of the scatter of distribution of individuals among species, the other factor affecting diversity. Using a method described by Hald, truncated lognormal curves were fitted to the phytoplankton data and estimates obtained for the mean, ξ, the logarithmic standard deviation, σ, the number of species in the modal octave, N_o, and the number of species in the population universe, N. Since one is interested in a sample only in so far as it reflects the properties of the population from whence it came, estimated population parameters were used to define measures of diversity by which means it was hoped to obtain a diversity index independent of sample size, i.e., a diversity value related more to the population than to the sample.     

Comparative analysis of rDNA distribution in chromosomes of various species of Brassicaceae

BACKGROUND AND AIMS: The Brassicaceae family encompasses numerous species of great agronomic importance, belonging to such genera, as Brassica, Raphanus, Sinapis and Armoracia. Many of them are characterized by extensive intraspecific diversity of phenotypes. The present study focuses on the polymorphism of number, appearance and chromosomal localization of ribosomal DNA (rDNA) sites and, when possible, in relation to polyploidy, in 42 accessions of Brassica species and ten accessions of Diplotaxis, Eruca, Raphanus and Sinapis species. METHODS: Chromosomal localization of ribosomal DNA was carried out using dual colour fluorescence in situ hybridization (FISH) with 5S rDNA and 25S rDNA sequences as probes on enzymatically digested root-tip meristematic cells. KEY RESULTS: Loci for 5S and 18S-5.8S-25S rDNA were determined for the first time in six taxa, and previously unreported rDNA constellations were described in an additional 12 accessions. FISH revealed frequent polymorphism in number, appearance and chromosomal localization of both 5S and 25S rDNA sites. This phenomenon was most commonly observed in the A genome of Brassica, where it involves exclusively pericentromeric sites of 5S and 25S rRNA genes. The intraspecific polymorphism was between subspecies/varieties or within a variety or cultivar (i.e. interindividual). CONCLUSIONS: The number of rDNA sites can differ up to 5-fold in species with the same chromosome number. In addition to the eight previously reported chromosomal types with ribosomal genes, three new variant types are described. The extent of polymorphism is genome dependent. Comparing the A, B and C genomes revealed the highest rDNA polymorphism in the A genome. The loci carrying presumably inactive ribosomal RNA genes are particularly prone to polymorphism. It can also be concluded that there is no obvious polyploidization-related tendency to reduce the number of ribosomal DNA loci in the allotetraploid species, when compared with their putative diploid progenitors. The observed differences are rather caused by the prevailing polymorphism within the diploids and allotetraploids. This would make it difficult to predict expected numbers of rDNA loci in natural polyploids.     

The influence of climatic factors on the distribution of C4 species in Europe

A checklist of the currently-known C4 species which occur in Europe was compiled, and the number of these found in European territories was ascertained. Their contribution to the local floras range from 4.35% in the Azores to 0% in Svalbard. Subsequently, a stepwise multiple regression analysis was used to correlate the relative abundances of four subdivisions of C4 species with climatic variables derived for each territory from meteorological tables. The four subdivisions were: (a) total number of C4 species; (b) number of native C4 species; (c) C4 monocots and (d) C4 dicots. These values were expressed as percentages of either the total flora, (a), or the native flora ((b), (c) and (d)) for the regressions. The abundance of each C4 subdivision was found to be strongly correlated with temperature, and to a lesser extent, negatively with precipitation. Habitat information about the European C4 species was also analysed and it was concluded that their apparent preference for maritime and ruderal habitats indicates some form of competitive advantage of the pathway under saline or disturbed conditions. A small number of European C4 species was identified whose distribution appears to be anomalous with respect to temperature and/or soil moisture content.Nomenclature follows Tutin et al. Flora Europaea.     

Binding of the gestagens norethisterone and levonorgestrel in blood of various species

This study investigates the binding of 2 widely used contraceptive steroids, levonorgestrel and norethisterone, by plasma from various animal species and compares the results to those obtained with human plasma. Equilibrium dialysis of plasma samples and polyacrylamide gel electrophoresis were performed as previously described. The plasma samples were diluted with phosphate-buffered saline on the percentage of levonorgestrel and norethisterone bound in comparison to human plasma. The concentration of total protein and albumin was measured colorimetrically in each sample. An ammonium sulphate precipitation technique measured the level of sex-hormone binding globulin (SHBG). Results of the equilibrium dialysis show that binding of levonorgestrel and norethisterone in plasma was similar in adult female rhesus monkeys and baboons to that of humans with both high-affinity and low-affinity classes of binding sites. The dissociation constants of the high-affinity class for levonorgestrel was 4-fold lower than that for norethisterone in all 3 primates, indicating levonorgestrel was more tightly bound. Total protein and albumin concentrations were also the same in all 3 primates. SHBG levels in female monkeys and baboons however were 3-4 times those found in normal human females. Although differences exist in the binding of the 2 gestagens between human, baboon, and rhesus monkey plasma, there are no significant differences in the metabolism of the gestagens in the 3 primates. Overall, the results indicate that in the human, baboon, and rhesus monkey, binding of norgestrel and norethisterone occur mainly to SHBG, which had a greater affinity for norgestrel than for norethisterone, and to a lesser extent, albumin. Differences in the binding of gestagens between human and nonprimate species (rat, dog, rabbit) studied suggest that only baboon and rhesus monkeys may be considered appropriate animal models for extrapolation of results of contraceptive studies to humans.     

The fate of benzoic acid in various species

1. The urinary excretion of orally administered [¹⁴C]benzoic acid in man and 20 other species of animal was examined. 2. At a dose of 50mg/kg, benzoic acid was excreted by the rodents (rat, mouse, guinea pig, golden hamster, steppe lemming and gerbil), the rabbit, the cat and the capuchin monkey almost entirely as hippuric acid (95–100% of 24h excretion). 3. In man at a dose of 1mg/kg and the rhesus monkey at 20mg/kg benzoic acid was excreted entirely as hippuric acid. 4. At 50mg/kg benzoic acid was excreted as hippuric acid to the extent of about 80% of the 24h excretion in the squirrel monkey, pig, dog, ferret, hedgehog and pigeon, the other 20% being found as benzoyl glucuronide and benzoic acid, the latter possibly arising by decomposition of the former. 5. On increasing the dose of benzoic acid to 200mg/kg in the ferret, the proportion of benzoyl glucuronide excreted increased and that of hippuric acid decreased. This did not occur in the rabbit, which excreted 200mg/kg almost entirely as hippuric acid. It appears that the hedgehog and ferret are like the dog in respect to their metabolism of benzoic acid. 6. The Indian fruit bat produced only traces of hippuric acid and possibly has a defect in the glycine conjugation of benzoic acid. The main metabolite in this animal (dose 50mg/kg) was benzoyl glucuronide. 7. The chicken, side-necked turtle and gecko converted benzoic acid mainly into ornithuric acid, but all three species also excreted smaller amounts of hippuric acid.     

云雾山天然草地物种分布与环境因子的关系

应用数量生态学中的梯度分析方法研究了云雾山天然草地群落类型、物种分布以及与环境因子的关系.研究结果表明,作为重要的人为管理措施,封育通过改善草地的水分、养分等环境条件,显著影响了云雾山草地的物种分布和群落类型.在封育草地,植被类型为本氏针茅群落,未封育草地为铁杆蒿群落.本氏针茅、百里香、大针茅、直茎点地梅、阿尔泰狗哇花等中旱生植物在封育草地中占优势,铁杆蒿、硬质早熟禾、星毛委菱菜等在退化草地中占优势.除封育措施以外,20～100cm 的土壤含水量对物种分布影响显著.同时,养分作为一个重要的环境因素对物种的分布也具有重要影响,特别是速效钾和NO-3-N.海拔、坡位、坡向等地形因素对植物分布的影响不明显.