Evolution of uni- and bifactorial sexual compatibility systems in fungi.

Mating systems, that is, whether organisms give rise to progeny by selfing, inbreeding or outcrossing, strongly affect important ecological and evolutionary processes. Large variations in mating systems exist in fungi, allowing the study of their origin and consequences. In fungi, sexual incompatibility is determined by molecular recognition mechanisms, controlled by a single mating-type locus in most unifactorial fungi. In Basidiomycete fungi, however, which include rusts, smuts and mushrooms, a system has evolved in which incompatibility is controlled by two unlinked loci. This bifactorial system probably evolved from a unifactorial system. Multiple independent transitions back to a unifactorial system occurred. It is still unclear what force drove evolution and maintenance of these contrasting inheritance patterns that determine mating compatibility. Here, we give an overview of the evolutionary factors that might have driven the evolution of bifactoriality from a unifactorial system and the transitions back to unifactoriality. Bifactoriality most likely evolved for selfing avoidance. Subsequently, multiallelism at mating-type loci evolved through negative frequency-dependent selection by increasing the chance to find a compatible mate. Unifactoriality then evolved back in some species, possibly because either selfing was favoured or for increasing the chance to find a compatible mate in species with few alleles. Owing to the existence of closely related unifactorial and bifactorial species and the increasing knowledge of the genetic systems of the different mechanisms, Basidiomycetes provide an excellent model for studying the different forces that shape breeding systems.

Accuracy of out-of-field dose calculation of tomotherapy and cyberknife treatment planning systems: A dosimetric study.

PURPOSE: Late toxicities such as second cancer induction become more important as treatment outcome improves. Often the dose distribution calculated with a commercial treatment planning system (TPS) is used to estimate radiation carcinogenesis for the radiotherapy patient. However, for locations beyond the treatment field borders, the accuracy is not well known. The aim of this study was to perform detailed out-of-field-measurements for a typical radiotherapy treatment plan administered with a Cyberknife and a Tomotherapy machine and to compare the measurements to the predictions of the TPS. MATERIALS AND METHODS: Individually calibrated thermoluminescent dosimeters were used to measure absorbed dose in an anthropomorphic phantom at 184 locations. The measured dose distributions from 6 MV intensity-modulated treatment beams for CyberKnife and TomoTherapy machines were compared to the dose calculations from the TPS. RESULTS: The TPS are underestimating the dose far away from the target volume. Quantitatively the Cyberknife underestimates the dose at 40cm from the PTV border by a factor of 60, the Tomotherapy TPS by a factor of two. If a 50% dose uncertainty is accepted, the Cyberknife TPS can predict doses down to approximately 10 mGy/treatment Gy, the Tomotherapy-TPS down to 0.75 mGy/treatment Gy. The Cyberknife TPS can then be used up to 10cm from the PTV border the Tomotherapy up to 35cm. CONCLUSIONS: We determined that the Cyberknife and Tomotherapy TPS underestimate substantially the doses far away from the treated volume. It is recommended not to use out-of-field doses from the Cyberknife TPS for applications like modeling of second cancer induction. The Tomotherapy TPS can be used up to 35cm from the PTV border (for a 390 cm(3) large PTV).

Agri-environmental evaluation of traditional and alternative corn production systems in Chiapas, Mexico

This study evaluates the effects of environmental variables on traditional and alternative agroecosystems in three Ejidos (communal lands) in the Chiapas rainforest in Mexico. The tests occurred within two seasonal agricultural cycles. In spring-summer, experiments were performed with the traditional slash, fell and burn (S-F-B) system, no-burn systems and rotating systems with Mucuna deeringiana Bort., and in the autumn-winter agricultural cycle, three no-burn systems were compared to evaluate the effect of alternative sowing with corn (no-burn and topological modification of sowing). The results show a high floristic diversity in the study area (S_S = 4 - 23%), with no significant differences among the systems evaluated. In the first cycle, the analysis of the agronomical variables of the corn indicated better properties in the fallowing systems, with an average yield of 1950 kg ha^‑1, but there was variation related to the number of years left fallow. In the second cycle, the yields were positive for the alternative technology (average yield 3100 kg ha^‑1). The traditional S-F-B systems had reduced pests and increased organic matter and soil phosphorous content. These results are the consequence of fallow periods and adaptation to the environment; thus, this practice in the Chiapas rainforest constitutes an ethnocultural reality, which is unlikely to change in the near future if the agrosystems are managed based on historical principles.

Spectrofluorimetric Determination of Second Critical Micellar Concentration of SDS and SDS/Brij 30 Systems

Potentially useful stead-state fluorimetric technique was used to determine the critical micellar concentrations (CMC(1) and CMC(2)) for two micellar media, one formed by SDS and the other by SDS/Brij 30. A comparative study based on conductimetric and surfacial tension measurements suggests that the CMC(1) estimated by the fluorimetric method is lower than the value estimated by these other techniques. Equivalent values were observed for SDS micelles without Brij 30 neutral co-surfactant. The use of acridine orange as fluorescent probe permitted to determine both CMC(1) and CMC(2). Based on it an explanation on aspects of micelle formation mechanism is presented, particularly based on a spherical and a rod like structures.

Effects of Silicon and Drought Stress on Tuber Yield and Leaf Biochemical Characteristics in Potato

Silicon has beneficial effects on many crops, mainly under biotic and abiotic stresses. Silicon can affect biochemical, physiological, and photosynthetic processes and, consequently, alleviates drought stress. However, the effects of Si on potato (Solanum tuberosum L.) plants under drought stress are still unknown. The objective of this study was to evaluate the effect of Si supply on some biochemical characteristics and yield of potato tubers, either exposed or not exposed to drought stress. The experiment was conducted in pots containing 50 dm(3) of a Typic Acrortox soil (33% clay, 4% silt, and 63% sand). The treatments consisted of the absence or presence of Si application (0 and 284.4 mg dm(-3)), through soil amelioration with dolomitic lime and Ca and Mg silicate, and in the absence or presence of water deficit (-0.020 MPa and -0.050 MPa soil water potential, respectively), with eight replications. Silicon application and water deficit resulted in the greatest Si concentration in potato leaves. Proline concentrations increased under lower water availability and higher Si availability in the soil, which indicates that Si may be associated with plant osmotic adjustment. Water deficit and Si application decreased total sugars and soluble proteins concentrations in the leaves. Silicon application reduced stalk lodging and increased mean tuber weight and, consequently, tuber yield, especially in the absence of water stress.

In vitro evaluation of conventional and locking miniplate/screw systems for the treatment of mandibular angle fractures

This in vitro study evaluated the influence of the type of miniplate and the number of screws installed in the proximal and distal segments on the stability and resistance of Champy's osteosynthesis in mandibular angle fractures. Sixty polyurethane hemimandibles with bone-like consistency were randomly assigned to four groups (n = 15) and sectioned in the mandibular angle region to simulate fracture. The bone segments were fixed by different osteosynthesis methods using 2.0 mm miniplates and 2.0 mm x 6 mm rnonocortical screws. In groups 1 and 2, two conventional (G1) or locking (G2) screws were installed in each bone segment using a conventional (G1) or a locking (02) straight miniplate; in groups 3 and 4, three conventional (03) or locking (04) screws were installed in the proximal segment and four conventional (G3) or locking (04) screws were installed in the distal segment using a conventional (G3) or a locking (G4) seven-hole straight miniplate. The hemimandibles were loaded in compressive strength until a 4 mm displacement occurred between the segments, vertically or horizontally. Locking plate/screw systems provided significantly greater resistance to displacement than conventional ones (p < .01). Locking miniplates offered more resistance than conventional miniplates. Long locking miniplates provided greater stability than short ones.

In Vitro Biomechanical Evaluation of the Use of Conventional and Locking Miniplate/Screw Systems for Sagittal Split Ramus Osteotomy

Purpose: The aim of this in vitro study was to assess the biomechanical stability of 9 different osteosynthesis methods after sagittal split ramus osteotomy by simulating the masticatory forces and using a 3-point biomechanical test method.Materials and Methods: Forty-five polyurethane hemimandibles with bone-like consistency were randomly assigned to 9 groups (n = 5) and subjected to sagittal split ramus osteotomy. After 4-mm advancement of the distal segment, the bone segments were fixed by different osteosynthesis methods using 2.0-mm miniplate/screw systems: group A, one 4-hole conventional straight miniplate; group B, one 4-hole locking straight miniplate; group C, one 4-hole conventional miniplate and one bicortical screw; group D, one 4-hole locking miniplate and 1 bicortical screw; group E, one 6-hole conventional straight miniplate; group F, one 6-hole locking straight miniplate; group (3: two 4-hole conventional straight miniplates; group H. two 4-hole locking straight miniplates; and group 1, 3 bicortical screws in an inverted-L. pattern. All models were mounted on a base especially constructed for this purpose. Using a 3-point biomechanical test model, the hemimandibles were loaded in compressive strength in an Instron machine (Norwood, MA) until a 3-mm displacement occurred between segments vertically or horizontally. Data were analyzed by analysis of variance and Tukey test (alpha = 1%).Results: The multiparametric comparison of the groups showed a statistically significant difference (P<.01) between groups that used 2 miniplates (groups G and H), 1 miniplate and 1 bicortical screw (groups C and D), and only bicortical screws (group D compared with groups that used only 1 miniplate with 2 screws per segment (groups A and B) and 3 screws per segment (groups E and F).Conclusion: The placement of 2.0-mm-diameter bicortical screws in the retromolar region, associated or not with conventional and locking miniplates with monocortical screws, promoted a better stabilization of bone segments. Locking miniplates presented a better performance in bone fixation in all groups. (C) 2010 American Association of Oral and Maxillofacial Surgeons J Oral Maxillofac Surg 68:724-730, 2010

A comparative study of the physical properties of conventional and Grander-modified adhesive systems

Purpose: The objective of this study was to evaluate the influence of the Grander technology in reducing the surface tension and contact angle of a self-etch adhesive system. Methods: Distilled water and Xeno III self-etch adhesive system (Dentsply) were modified by physical contact with the Flexible unit Grander system to revitalize water, for 48 hours, resulting in four groups: Group 1 - Xeno III under normal conditions; Group 2 - Xeno III modified by Grander; Group 3 - distilled water under normal conditions; Group 4 - distilled water system modified by the Grander system;. Surface tension and contact angle (dentin substrate and titanium plate) of the adhesive system and water in normal and Grander-modified conditions was measured with a goniometer. Data were analyzed by ANOVA and Tukey test (5%). Results: Grander technology reduced the surface tension of water but not of the adhesive system Xeno III. The contact angle property of the adhesive ystem was not affected. Conclusion: Grander technology did not interfere with the surface tension and contact angle physical properties of the Xeno III self-etch adhesive system. Copyright: © 2011 Gonçalves et al.;.

Perspectives on the use of lakes and ponds as model systems for macroecological research

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Down-regulation of ANAPC13 and CLTCL1: Early Events in the Progression of Preinvasive Ductal Carcinoma of the Breast

Alterations in the gene expression profile in epithelial cells during breast ductal carcinoma (DC) progression have been shown to occur mainly between pure ductal carcinoma in situ (DCIS) to the in situ component of a lesion with coexisting invasive ductal carcinoma (DCIS-IDC) implying that the molecular program for invasion is already established in the preinvasive lesion. For assessing early molecular alterations in epithelial cells that trigger tumorigenesis and testing them as prognostic markers for breast ductal carcinoma progression, we analyzed, by reverse transcription-quantitative polymerase chain reaction, eight genes previously identified as differentially expressed between epithelial tumor cells populations captured from preinvasive lesions with distinct malignant potential, pure DCIS and the in situ component of DCIS-IDC. ANAPC13 and CLTCL1 down-regulation revealed to be early events of DC progression that anticipated the invasiveness manifestation. Further down-regulation of ANAPC13 also occurred after invasion appearance and the presence of the protein in invasive tumor samples was associated with higher rates of overall and disease-free survival in breast cancer patients. Furthermore, tumors with low levels of ANAPC13 displayed increased copy number alterations, with significant gains at 1q (1q23.1-1q32.1), 8q, and 17q (17q24.2), regions that display common imbalances in breast tumors, suggesting that down-regulation of ANAPC13 contributes to genomic instability in this disease.

A 5-year comparison of performance of sentinel and mandatory notification surveillance systems for measles in Switzerland

A sensitive, specific and timely surveillance is necessary to monitor progress towards measles elimination. We evaluated the performance of sentinel and mandatory-based surveillance systems for measles in Switzerland during a 5-year period by comparing 145 sentinel and 740 mandatory notified cases. The higher proportion of physicians who reported at least one case per year in the sentinel system suggests underreporting in the recently introduced mandatory surveillance for measles. Accordingly, the latter reported 2-36-fold lower estimates for incidence rates than the sentinel surveillance. However, these estimates were only 0.6-12-fold lower when we considered confirmed cases alone, which indicates a higher specificity of the mandatory surveillance system. In contrast, the sentinel network, which covers 3.5% of all outpatient consultations, detected only weakly and late a major national measles epidemic in 2003 and completely missed 2 of 10 cantonal outbreaks. Despite its better timeliness and greater sensitivity in case detection, the sentinel system, in the current situation of low incidence, is insufficient to perform measles control and to monitor progress towards elimination.

Chemistry of pyrrocorphins: C-methylations at the periphery of pyrrocorphins and related corphinoid ligand systems

Various corphinoid model systems bearing a methyl group at the position C-20 have been found to undergo regioselective chemical -methylation at the ligand periphery, mimicking enzymic -methylation occurring in vitamin-B biosynthesis.