Degradation of the neolignan, burchellin in the hemolymph of the bloodsucking insect Rhodnius prolixus

The neolignan, burchellin, a natural compound that reduces urine excretion in larvae of the bloodsucking bug, Rhodnius prolixus, a vector of Chagas' disease, is rapidly degraded in the hemolymph of the insect. The main product that accumulates in this tissue has been shown to be piperonyl alcohol. Other catabolites have been identified by GC-MS analysis.     

Dose–response relationships between wood moisture content,wood temperature and fungal decay determined for 23 European field test sites

Scots pine sapwood (Pinus sylvestris L.) and Douglas fir heartwood (Pseudotsuga menziesii Franco) specimens were exposed in double layer field trials at 23 different European test sites under different exposure conditions (in total 27 test sets). The material climate in terms of wood moisture content (MC) and wood temperature was automatically monitored over a period of up to 7 years and compared with the progress of decay. The overall aim of this study was to establish dose–response relationships between climate factors and decay as a basis for the service life prediction of wood. The “Scheffer Climate Index” based on weather data collected at official meteorological stations at the different test sites poorly correlated with the corresponding decay progress and was therefore not a suitable tool for estimating site-specific decay potential. In contrast, the use of the combined material climatic parameters MC and wood temperature led to a feasible dose–response function and turned out to be a useful basis for service life prediction of wood.     

Colostrum yield and litter performance in multiparous sows subjected to farrowing induction

The consumption of colostrum at a low level can compromise the survival and growth of piglets. Therefore, this study aimed to evaluate the effect of farrowing induction on colostrum yield, IgG concentration and the survival and performance of piglets until the weaning. Sows of parity 3 to 7 were assigned into two groups: Control (n = 48), sows with spontaneous farrowing; and induction (n = 48), sows induced to farrow on day 114 of gestation with a PGF₂ analogue. Colostrum and blood samples were collected from the sows, at farrowing and 24 hr later. Blood samples from the piglets were collected at 24 hr after birth. The performance of the piglets was evaluated in a subsample of 28 litters from each group. All piglets were weighed at 7, 14 and 20 days of age. The farrowing length, the number of piglets born alive, stillborn piglets, weight at birth, litter weight at birth and colostrum yield were not significantly affected (p > .05) by farrowing induction. There was no difference between the groups (p > .05) in the percentage of sows with obstetric interventions. Serum IgG concentration, in both sows and piglets, and colostrum IgG concentration were similar between the groups (p > .05). Furthermore, survival rate, piglet weight and litter weight at 7, 14 and 20 days of age were also similar between the groups (p > .05). Therefore, it can be concluded that the farrowing induction performed on day 114 of gestation does not affect the colostrum yield, the IgG concentration in colostrum and serum of piglets, and the litter performance until the weaning.     

Protein adsorption on and swelling of polyelectrolyte brushes: A simultaneous ellipsometry-quartz crystal microbalance study

With a coupled spectroscopic ellipsometry-quartz crystal microbalance with dissipation (QCM-D) experimental setup, quantitative information can be obtained about the amount of buffer components (water molecules and ions) coupled to a poly(acrylic acid) (PAA) brush surface in swelling and protein adsorption processes. PAA Guiselin brushes with more than one anchoring point per single polymer chain were prepared. For the swollen brushes a high amount of buffer was found to be coupled to the brush-solution interface in addition to the content of buffer inside the brush layer. Upon adsorption of bovine serum albumin the further incorporation of buffer molecules into the protein-brush layer was monitored at overall electrostatic attractive conditions [below the protein isolectric poimt (IEP)] and electrostatic repulsive conditions (above the protein IEP), and the shear viscosity of the combined polymer-protein layer was evaluated from QCM-D data. For adsorption at the "wrong side" of the IEP an incorporation of excess buffer molecules was observed, indicating an adjustment of charges in the combined polymer-protein layer. Desorption of protein at pH 7.6 led to a very high stretching of the polymer-protein layer with additional incorporation of high amounts of buffer, reflecting the increase of negative charges on the protein molecules at this elevated pH.     

Mutational robustness of ribosomal protein genes

The distribution of fitness effects (DFE) of mutations is of fundamental importance for understanding evolutionary dynamics and complex diseases and for conserving threatened species. DFEs estimated from DNA sequences have rarely been subject to direct experimental tests. We used a bacterial system in which the fitness effects of a large number of defined single mutations in two ribosomal proteins were measured with high sensitivity. The obtained DFE appears to be unimodal, where most mutations (120 out of 126) are weakly deleterious and the remaining ones are potentially neutral. The DFEs for synonymous and nonsynonymous substitutions are similar, suggesting that in some genes, strong fitness constraints are present at the level of the messenger RNA.     

Effect of the thin cell layer technique in the induction of somatic embryos in Pinus patula Schl. et Cham

Pinus patula is a species commonly used for reforestation in Mexico.However,efficient methods for the mass production seedlings are required.Micropropagation particularly by somatic embryogenesis provides an option for the rapid multiplication of high-quality,genetically improved material.This study induces somatic embryogenesis in this species using the thin cell layer(TCL)technique.Two sources of explants(complete immature embryos;lTCL segments from immature embryos)were evaluated.The efficiency of TCL from longitudinal sections[lTCL]and transverse[tTCL]was evaluated.The results show using thin cell layers from immature embryos cultivated in 16 light/8 dark hours achieves induction of somatic embryos.A higher percentage of embryogenic callus was obtained when tTCL segments were used as an explant source.These results produced somatic embryos from tTCL segments of an immature embryo without germinating the seed,making the process more time efficient.In addition,this technique can be used to generate somatic embryogenesis in forest species that have low germination rates.     

A Biomechanical Comparison of Screw and Wire Fixation With and Without Polymethylmethacrylate Re-Enforcement for Acetabular Osteotomy Stabilization in Dogs

Objective— Compare the biomechanical characteristics of screw and wire fixation with and without polymethylmethacrylate (PMMA) re-enforcement for acetabular osteotomy stabilization in dogs. Animals— Pelves removed from 8 adult mixed breed dogs weighing between 25 and 30 kg. Procedure— The pubic symphysis of each pelvis was split and a central transverse acetabular osteotomy was performed. One hemipelvis from each dog was stabilized with the composite fixation (interfragmentary Kirschner wire, two screws and a figure-of-eight orthopedic wire with PMMA). The contralateral hemipelves was stabilized with an interfragmentary Kirschner wire, two screws, and a figure-of-eight orthopedic wire without PMMA. All hemipelves were tested in bending by using a materials testing machine at a cross head speed of 5 mm/min. An extensometer was placed on the dorsomedial surface of the hemipelves centered over acetabular osteotomy to record distraction of the osteotomy during loading. A load/deformation curve and a load/distraction curve was produced for each hemipelvis. The slope for the initial linear portion of the load/deformation curve and the load/distraction curve, yield load and maximum load sustained were compared between repair groups using a paired t-test with P < .05 considered significant. Results— The slope of the load/deformation curve was significantly greater (P= .001 ) for hemipelves stabilized with the composite fixation (mean ± SD: 69 ± 18 N/mm) compared with hemipelves stabilized without PMMA (mean ± SD: 39 ± 8 N/mm). There was no significant difference (P= .593 ) between repair groups in the slope of the load/distraction curves as measured on the extensometer. Yield load was significantly greater (P= .0002 ) for hemipelves stabilized with the composite fixation (mean ± SD: 184 ± 25 N) compared to hemipelves stabilized without PMMA (mean ± SD: 74 ± 12 N). Maximum load sustained was also significantly greater (P= .013 ) for hemipelves stabilized with the composite fixation (mean ± SD: 396 ± 71 N) compared to hemipelves stabilized without PMMA (mean ± SD: 265 ± 94 N). Failure of hemipelves stabilized with the composite fixation occurred primarily by ventrolateral bending of the cranial and caudal pelvic segments at the osteotomy site. Failure of hemipelves stabilized without PMMA occurred by ventrolateral bending of the cranial and caudal pelvic segments at the osteotomy site with pronounced concurrent ventrolateral rotation of the cranial pelvic segment. Conclusion— PMMA improves the mechanical characteristics of acetabular fracture fixation, at least in part by neutralization of rotational forces. The results of this study justify use of PMMA as a component of the composite fixation when repairing acetabular fractures.     

Heuschreckenplage in Ostafrika und ihre Bekämpfung

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