Notes on the genus Quekettia (Orchidaceae) with descriptions of two new species from Colombia and Guyana

Two new species of the orchid genus Quekettia are described. Colombian Quekettia aureliae is distinguished from similar Q. microscopica by the pandurate lip with a pair of small, flap‐like calli in the isthmus between hypo‐ and epichile, and deeply emarginated epichile apex. Quekettia senghasiana found in Guyana resembles Q. papillosa but it is characterized by the free lateral sepals, oblanceolate, obtuse petals and much larger lip which is oblong–obovate in outline and with lip disc being papillate only near the base.     

Quantification of Alternaria,Cladosporium, Fusarium and Penicillium verrucosum in Conventional and Organic Grains by qPCR

We analysed the levels of Alternaria, Cladosporium, Fusarium and Penicillium verrucosum in grain samples harvested in 2011 and 2012 from conventional and organic farms using qPCR. In general, both Alternaria and Cladosporium occurred in all cereal grains in the highest quantities, followed by P. verrucosum and Fusarium. Alternaria, Cladosporium and P. verrucosum had the highest levels in crop mixtures, barley and rye and lower levels in wheat, while Fusarium levels were the highest in crop mixtures and wheat. The levels of Alternaria and P. verrucosum were higher in organic rye and wheat than conventional grains. Although the level of Fusarium was higher in conventional than organic rye, opposite results were obtained for crop mixtures. A positive correlation was found between Alternaria, Cladosporium and P. verrucosum, indicating that similar factors might affect the distribution of these fungi in grains.     

Predation-mediated coexistence of large- and small-bodied Daphnia at different food levels

Using an individual-based age-structured population model (a combination of O'Brien's apparent-prey-size approach, Eggers's reactive-field-volume model, and Holling's disk equation), we could predict that (1) a Daphnia population could be kept at low density by fish predation irrespective of food level, with greater recruitment at higher food being instantly compensated for by raised mortality reflecting increased predation, and (2) Daphnia density levels are species specific and inversely related to both body size at first reproduction and the reaction distance at which a foraging fish sees its Daphnia prey. These two hypotheses were experimentally tested in outdoor mesocosms with two Daphnia species of different body sizes grown in the absence or presence of fish that were allowed to feed for 2-3 h each evening. While each Daphnia quickly reached high density with reproduction halted by food limitation in the absence of fish, the populations stayed at much lower species-specific density levels, similar in low and high food concentrations, in the presence of fish. This suggests that our model offers a reasonable mechanistic explanation for the coexistence of large- and small-bodied zooplankton in proportions reflecting their body sizes throughout habitats comprising a wide productivity spectrum, with each species at a density level at which it becomes included in a predator's diet.     

A method for developing high-density SNP maps and its application at the type 1 angiotensin II receptor (AGTR1) locus

Evaluating the potential genetic components of complex disease will likely be aided through the use of dense polymorphism maps. Previously, we reported evidence for linkage with diabetic nephropathy on chromosome 3q in a region encompassing the type 1 angiotensin II receptor (AGTR1) gene. To further investigate any role for this gene in disease onset, we set out to design a dense polymorphism map spanning the AGTR1 locus for the purpose of association studies. Toward this goal, we have developed a technique for rapid identification of polymorphisms in long stretches of genomic DNA. This approach uses long-range PCR, DNA pooling, and transposon-based DNA sequencing. Using this technique, we efficiently validated and genotyped 18 polymorphisms spanning the 60.5-kb AGTR1 locus. Our panel of polymorphisms has an average spacing of 3.2 kb and an average minor allele frequency of 24%.     

Bone marrow angiogenesis and proliferation in B-cell chronic lymphocytic leukemia

OBJECTIVE: To assess angiogenesis and the proliferative activity of bone marrow in patients with chronic lymphocytic leukemia (CLL) in relation to the bone marrow infiltration pattern. STUDY DESIGN: Bone marrow samples were obtained by trephine biopsy from 46 patients with B-cell CLL (B-CLL). Infiltration pattern was diffuse in 20 patients and nondiffuse--i.e., nodular, interstitial or mixed--in the remaining 26 patients. Ten normal bone marrow samples were used as a control group. Studies were carried out by immunohistochemical staining of paraffin-embedded bone marrow samples. Angiogenesis was assessed in the zones of highest vascular density (hot spots), visualized by the expression of endothelial antigen CD34 and expressed as a number of microvessels per high-powerfield (hpf) (final magnification, 400x). Proliferative activity was estimated by the expression of nuclear protein Ki-67, cyclin A and mean number of nucleolar organizer regions (AgNORs). RESULTS: Microvessel density was higher in B-CLL marrow than in normal marrow (30.1 and 16.44 per hpf, respectively) and was higher in the diffuse than nondiffuse pattern (33.6 and 27.5 per hpf, respectively). B-CLL bone marrow also showed higher proliferative activity, as assessed by mean number of AgNORs, than did normal marrow (1.52 and 1.25, respectively) and a higher mean percentage of cyclin A-positive cells (7.5 and 6.8, respectively). In contrast, mean Ki-67 expression was similar in B-CLL and the control group. Mean AgNORs number, Ki-67 and cyclin A-positive cell percentage were significantly higher in B-CLL marrow with a diffuse as compared to nondiffuse involvement pattern (AgNORs, 1.75 and 1.35; cyclin A, 9.27% and 3.95%; Ki-67, 34.9% and 23.3%, respectively). CONCLUSION: Our results indicate enhancement of bone marrow angiogenesis in B-CLL and a relationship between microvessel density and the bone marrow infiltration pattern. The study points also to a possible relationship between the bone marrow infiltration pattern and proliferative activity of bone marrow cells.     

A sensitive and specific HPLC method for the determination of total pentosidine concentration in plasma

Pentosidine is an advanced glycation end-product (AGE) appearing when arginine and lysine residues in proteins are cross-linked with carbonyl derivatives. This paper presents an improved method for the synthesis of pentosidine and reversed-phase chromatography of this substance with fluorometric detection that enables sensitive (0.01 pmol/mg protein) and specific determination of pentosidine in plasma. Separation is done twice on the same C(18) Vydac 218TP54 column, first with trifluoroacetic acid and next with heptafluorobutyric acid as ion pair. The inter-day coefficient of variation is 6.4% at pentosidine concentration in plasma of 25 pmol/mg protein and 8% at 1.7 pmol/mg protein. Spectral properties of pentosidine exploited during identification of the substance with UV absorption and fluorescence detectors are described. Maximum of absorbance was observed at 325 nm, maximum fluorescence at lambda(ex)/lambda(em)=330/373 nm. The method may prove useful for the study of processes associated with generation and accumulation of pentosidine in the body as a marker of AGE production in healthy subjects and patients with chronic renal failure.     

Attractiveness of men's faces in relation to women's phase of menstrual cycle

In between-subjects studies on two groups of women of the same age, we show that women assess male's facial attractiveness differently in the follicular (F) and luteal (L) phases. In the high conception risk phase (F), women tended to give higher scores to male faces than when they were in the luteal phase. During the five first days of the cycle, i.e. when the estrogen level is still low, women assessed men's facial attractiveness relatively highly. We suggest that it is progesterone in the luteal phase that is responsible for lower attractiveness assigned then to male faces. We also tested which anthropometric facial traits or indices influence male attractiveness. We found that assessments of attractiveness were correlated only with mouth height (positively) and the angle between the middle of the mouth and the middle of the eyes (negatively). The results are compared with those from other studies and discussed in the light of evolutionary biology.     

Excitation energy transfer kinetics and efficiency in phototrophic green sulfur bacteria

A series of spectroscopic measurements were performed on membrane fractions and detergent-solubilized complexes from the green sulfur bacterium (GSB) Chlorobaculum (Cba.) tepidum. The excitation migration through the entire GSB photosynthetic apparatus cannot be observed upon excitation of membranes in the chlorosome region at 77?K. In order to observe energy transfer from the Fenna-Matthews-Olson (FMO) protein to the reaction center (RC), FMO was directly excited at ~800?nm in transient absorption experiments. However, interpretation of the results is complicated by the spectral overlap between FMO and the RC. The availability of the Y16F FMO mutant, whose absorption spectrum is drastically different from that of the WT, has enabled the selection of spectral regions where either only FMO or the RC contributes. The application of a directed kinetic modeling approach, or target analysis, revealed the various decay and energy transfer pathways within the pigment-protein complexes. The calculated FMO-to-RC excitation energy transfer efficiencies are approximately 25% and 48% for the Y16F and WT samples, respectively.