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951.
The use of hypothermia as a means to save energy is well documented in birds. This energy‐saving strategy is widely considered to occur exclusively at night in diurnally active species. However, recent studies suggest that facultative hypothermia may also occur during the day. Here, we document the use of daytime hypothermia in foraging Black‐capped Chickadees Poecile atricapillus wintering in eastern Canada. We measured the body temperature (Tb) of 126 individuals (plus 48 repeated measures) during a single winter and related values to ambient temperature (Ta) at the time of capture. We also tested whether daytime hypothermia was correlated with the size of body reserves (residuals of mass on structural size and fat score) and levels of metabolic performance (basal metabolic rate and maximum thermogenic capacity). We found that Tb of individual birds was lower when captured at low Ta, reaching values as low as 35.5 °C in actively foraging individuals. Tb was unrelated to metabolic performance or measures of body reserves. Therefore, daytime hypothermia does not result from individuals being unable to maintain Tb during cold spells or to a lack of body reserves. Our data also demonstrated a high level of individual variation in the depth of hypothermia, the causes of which remain to be explored. 相似文献
952.
Zübeyde Kumbiçak 《Biologia》2014,69(5):644-650
Karyotypes, sex chromosome systems and meiotic characteristics are reported for ten spider species belonging to the families Gnaphosidae, Philodromidae, Salticidae, Oxyopidae and Sicariidae by using standard Giemsa staining. The male diploid numbers (2n) and sex chromosome systems are as follows: Berinda hakani 2n = 22 (X1X2), Berinda ensigera 2n = 22 (X1X2), Trachyzelotes lyonneti 2n = 22 (X1X2), Trachyzelotes malkini 2n = 22 (X1X2), Zelotes caucasius 2n = 22 (X1X2) (Gnaphosidae); Thanatus pictus 2n = 28 (X1 X2), Tibellus macellus 2n = 24 (X1 X2) (Philodromidae); Neon reticulatus 2n = 21 (X0) (Salticidae); Peucetia virescens 2n = 28 (X1X2) (Oxyopidae) and Loxosceles rufescens 2n = 21 (X1 X2Y) (Sicariidae). All species have monoarmed chromosomes with the exception of L. rufescens that has biarmed (metacentric and submetacentric) chromosomes. The obtained data are the first results for the genera Berinda, Trachyzelotes and Neon. Additionally, with the exception of L. rufescens, all species are being chromosomally analyzed for the first time. 相似文献
953.
Ana Z. Gonçalves Fernando L. Hoffmann Helenice Mercier Paulo Mazzafera Gustavo Q. Romero 《Biotropica》2014,46(2):170-174
Many plant species have evolved special adaptations for acquiring nitrogen in nutrient‐poor soils. In Brazilian savannas, the bromeliad Bromelia balansae (Bromeliaceae) is inhabited by mutualistic spiders (Psecas chapoda, Salticidae), which provide nutrients to the plant through their debris (feces, prey carcasses). In this study, we tested if bacteria present on the B. balansae phyllosphere improves plant nutrition and growth by mineralizing complex organic N compounds from spider debris that accumulate on the phyllosphere into simple compounds that may be absorbed easily by leaves. We conducted a greenhouse experiment by manipulating bacteria abundance on the bromeliad phyllosphere using antibiotics. Using isotopic mixed model equations, we demonstrated that debris from spiders contributed 10.7 ± 1.9 percent (mean ± standard error) of the N in bromeliads that had their bacterial abundance reduced. In contrast, spider feces contributed 27.1 ± 4.4 percent of bromeliad N in the presence of the entire bacterial assemblage. These bromeliads accumulated 57 percent more soluble protein and grew 13 percent more than bromeliads that were grown under reduced bacterial density. These results highlight the importance of mineralizing bacteria on phyllosphere as a mechanism of N uptake by bromeliads. 相似文献
954.
Michael Garratt Robert C Brooks Jean‐François Lemaître Jean‐Michel Gaillard 《Evolution; international journal of organic evolution》2014,68(4):1207-1215
Conflicts between family members are expected to influence the duration and intensity of parental care. In mammals, the majority of this care occurs as resource transfer from mothers to offspring during gestation and lactation. Mating systems can have a strong influence on the severity of familial conflict—where female promiscuity is prevalent, conflict is expected to be higher between family members, causing offspring to demand more resources. If offspring are capable of manipulating their mothers and receive resources in proportion to their demands, resource transfer should increase with elevated promiscuity. We tested this prediction, unexplored across mammals, using a comparative approach. The total durations of gestation and lactation were not related to testes mass, a reliable proxy of female promiscuity across taxa. Offspring growth during gestation, however, and weaning mass, were positively correlated with testes mass, suggesting that offspring gain resources from their mothers at faster rates when familial conflict is greater. During gestation, the relationship between offspring growth and testes mass was also related to placenta morphology, with a stronger relationship between testes mass and growth observed in species with a less invasive placenta. Familial conflict could have a pervasive influence on patterns of parental care in mammals. 相似文献
955.
Extraction of extracellular polymeric substances (EPS) from anaerobic granular sludges: comparison of chemical and physical extraction protocols 总被引:9,自引:0,他引:9
Paul D’Abzac François Bordas Eric Van Hullebusch Piet N. L. Lens Gilles Guibaud 《Applied microbiology and biotechnology》2010,85(5):1589-1599
The characteristics of the extracellular polymeric substances (EPS) extracted with nine different extraction protocols from
four different types of anaerobic granular sludge were studied. The efficiency of four physical (sonication, heating, cationic
exchange resin (CER), and CER associated with sonication) and four chemical (ethylenediaminetetraacetic acid, ethanol, formaldehyde
combined with heating, or NaOH) EPS extraction methods was compared to a control extraction protocols (i.e., centrifugation).
The nucleic acid content and the protein/polysaccharide ratio of the EPS extracted show that the extraction does not induce
abnormal cellular lysis. Chemical extraction protocols give the highest EPS extraction yields (calculated by the mass ratio
between sludges and EPS dry weight (DW)). Infrared analyses as well as an extraction yield over 100% or organic carbon content
over 1 g g−1 of DW revealed, nevertheless, a carry-over of the chemical extractants into the EPS extracts. The EPS of the anaerobic granular
sludges investigated are predominantly composed of humic-like substances, proteins, and polysaccharides. The EPS content in
each biochemical compound varies depending on the sludge type and extraction technique used. Some extraction techniques lead
to a slightly preferential extraction of some EPS compounds, e.g., CER gives a higher protein yield. 相似文献
956.
Arlindo C. Motta-Silva Natanael A. Aleva Jorge K. Chavasco Mônica C. Armond Julieta P. França Luciano José Pereira 《Mycopathologia》2010,169(3):215-223
Diabetes mellitus (DM) is a systemic condition characterized by a deficient sugar metabolism, which affects the immune system
and favors the development of yeasts. The aim of the present study was to perform biochemical, morphological, exoenzyme analyses
of Candida species and the molecular identification (DNA) of C. albicans in patients with type II diabetes mellitus. The exoenzyme quantification was compared to non-diabetic patients as controls.
Two hundred and seventy-four patients who make use of complete dentures were evaluated, 28 of whom had diabetes and erythematous
oral candidiasis. Other thirty patients presented the same clinical feature but without diabetes. Samples were isolated for
biochemical identification (auxonogram), morphological identification (production of germ tubes) and PCR molecular identification
(DNA). The capability of the Candida samples in producing phospholipases and proteinases was also determined. The diabetic patients had a greater diversity of
Candida species (Fischer’s exact test, P = 0.04). The production of proteinases by C. albicans in patients with diabetes was greater than in the control group (unpaired “t” test P < 0.003). However, there was no difference between groups for phospholipase production (unpaired “t” test P > 0.05). It was concluded that patients with controlled DM exhibited systemic conditions predisposing C. albicans proteinase increased production. 相似文献
957.
Elif Şahin Horasan Gülden Ersöz Musa Göksu Feza Otag Ahmet Oner Kurt Sevim Karaçorlu Ali Kaya 《Mycopathologia》2010,170(4):263-268
Objectives
We aimed to asses possible clinically significant differences between C. parapsilosis and other candida species candidemia receiving care in the intensive care unit (ICU) setting.Methods
The study included 118 adult patients diagnosed as candidemia after admission to the ICU of a university hospital between January 2004 and December 2009. Data about demographic characteristics, underlying diseases, and risk factors for ICU-related candidemia were collected.Results
During the study period, 118 patients with candidemia were identified among 2,853 patients admitted into the ICU. Candidemia was seen in 41.4 cases per 1,000 ICU admissions. The overall incidence of candidemia in ICU patients during the study period was 2.09 per 1,000 hospital admissions. Of the isolates, 18.6% were C. albicans and 81.4% were C. non-albicans. The species most frequently isolated was C. parapsilosis (66.1%, 78/118). The distribution of other Candida spp. was as follows: 15 had C. tropicalis (12.7%) and 3 had C. glabrata (2.5%). By Statistical analysis, when patients with candidemia who had C. parapsilosis were compared with other Candida spp., the following factors were found to be significantly associated with C. parapsilosis fungemia; intravascular catheters (p = 0.008), malignity (p = 0.049) and age (p = 0.039). Relationship was found between C. tropicalis and hematologic malignancies (p = 0.001).Conclusions
When infections with a high mortality such as candidemia is suspected in critically ill patients, it is important to know local risk factors and epidemiological distributions of causative agents in selection of empirical and effective antifungal treatment. 相似文献958.
Jean-Marc Bertho Sonia Louiba Marie-Cécile Faure Elie Tourlonias Johanna Stefani Baptiste Siffert François Paquet Isabelle Dublineau 《Radiation and environmental biophysics》2010,49(2):239-248
The aim of this work was to define the possible occurrence of hematological changes during the course of a chronic ingestion
of 137Cs. A mouse model was used, with ingestion through drinking water with a cesium concentration of 20 kBq l−1. Ingestion started in parent animals before mating, and 137Cs intake and its effect on the hematopoietic system was studied in offspring at various ages between birth and 20 weeks.
137Cs content was measured in various organs, indicating that 137Cs was distributed throughout the organism including lympho-hematopoietic organs, i.e., femurs, spleen and thymus. However,
we did not observe any effect on the hematopoietic system, whatever the parameter used. In fact, blood cell counts, mononuclear
cell counts and progenitor frequency in bone marrow and spleen, and Flt3-ligand, Erythropoietin, G-CSF and SDF-1 concentration
in plasma remained unchanged when compared to control animals. Moreover, phenotypic analysis did not show any change in the
proportions of bone marrow cell populations. These results indicate that, although 137Cs was found in all organs implicated in the hematopoietic system, this did not induce any changes in bone marrow function. 相似文献
959.
960.
Maurício Papa de Arruda Evonnildo Costa Gonçalves Maria Paula Cruz Schneider Artur Luiz da Costa da Silva Eliana Morielle-Versute 《Molecular biology reports》2010,37(4):2031-2036
We proposed a modification the procedure of genotyping based in labeled universal primer and tailed primer. In the standard
protocol, three primers are used in the same PCR reaction, a forward primer with tail added at the 5′ end of the identical
sequence to labeled universal primer with dye-fluorescent and a reverse primer. Unfortunately, the choice of a labeled primer
characterized by a large number of complementary sequences in target genomes (which is more probable in larger genomes) result
in unspecific amplifications (false positive) can cause absence or decrease amplification of the locus of interest and also
false interpretation of the analysis. However, identification of possible homologies between the primer chosen for labelling
and the genome is rarely possible from the available DNA data bases. In our approach, cycling is interrupted for the addition
of the labeled primer only during the final cycles, thus minimizing unspecific amplification and competition between primers,
resulting in the more fidelity amplification of the target regions. 相似文献