Mining the genetic diversity of Ehrlichia ruminantium using map genes family

Understanding bacterial genetic diversity is crucial to comprehend pathogenesis. Ehrlichia ruminantium (E. ruminantium), a tick-transmitted intracellular bacterial pathogen, causes heartwater disease in ruminants. This model rickettsia, whose genome has been recently sequenced, is restricted to neutrophils and reticulo-endothelial cells of its mammalian host and to the midgut and salivary glands of its vector tick. E. ruminantium harbors a multigene family encoding for 16 outer membrane proteins including MAP1, a major antigenic protein. All the 16 map paralogs are expressed in bovine endothelial cells and some are specifically translated in the tick or in the mammalian host.In this study, we carried out phylogenetic analyses of E. ruminantium using sequences of 6 MAP proteins, MAP1, MAP1-2, MAP1-6, MAP1-5, MAP1+1 and MAP1-14, localized either in the center or at the borders of the map genes cluster.We show that (i) map1 gene is a good tool to characterize the genetic diversity among Africa, Caribbean islands and Madagascar strains including new emerging isolates of E. ruminantium; (ii) the different map paralogs define different genotypes showing divergent evolution; (iii) there is no correlation between all MAP genotypes and the geographic origins of the strains; (iv) The genetic diversity revealed by MAP proteins is conserved whatever is the scale of strains sampling (village, region, continent) and thus was not related to the different timing of strains introduction, i.e. continuous introduction of strains versus punctual introduction (Africa versus Caribbean islands).These results provide therefore a significant advance towards the management of E. ruminantium diversity. The differential evolution of these paralogs suggests specific roles of these proteins in host–vector–pathogen interactions that could be crucial for developing broad-spectrum vaccines.     

In vitro mechanical comparison of screwed, bolted, and novel interlocking nail systems to buttress plate fixation in torsion and mediolateral bending

Objective— To compare standard interlocking nails (ILN) with a newly designed ILN featuring an angle-stable locking mechanism (ILNn).
Study design— Six experimental groups.
Sample population— Bone models (n=48) treated with 6 and 8 mm nails locked with screws or bolts (ILN6s, ILN8s, ILN6b, ILN8b, respectively), ILNn, and a 3.5 mm broad-DCP (br-DCP); n=4/testing mode.
Methods— Specimens were tested in torsion or 4-point bending. Construct compliance, deformation, and slack were statistically compared ( P <.05).
Results— Regardless of testing mode, construct compliance was greater with smaller ILN. Screwed constructs were more compliant than bolted ones, with a significant difference between ILN6s and ILN6b in torsion. Plated constructs were significantly more compliant than the ILNn. Angular deformation was consistently greater with smaller ILN. Screwed ILN constructs sustained ∼2 × the torsional deformation of the bolted ones (∼36° [ILN6s] versus ∼18° [ILN6b]). Comparatively, ILNn constructs had significantly less torsional (∼8°) and bending (∼4°) deformation than other constructs. Whereas standard ILN constructs had slack in both modes, ILNn and br-DCP construct deformations consistently occurred without slack.
Conclusions— Use of bolts rather than screws improved ILN mechanical behavior, but neither locking mechanism completely counteracted torsion and bending forces. Conversely, the ILNn angle-stable locking system eliminated torsional and bending slack, resulting in comparable mechanical performances between ILNn and plated constructs.
Clinical Relevance— The angle-stable locking mechanism of the new ILN eliminates all slack in the system; thus, interfragmentary motion will likely be reduced compared with standard ILN, which may improve the local environment for fracture healing.     

Tibial plateau symmetry and the effect of osteophytosis on tibial plateau angle measurements

A novel technique was developed to estimate the caudal medial tibial plateau landmark in the face of osteophytosis to improve accuracy in tibial plateau angle measurements. Using this technique, tibial plateau angles were evaluated in 31 normal dogs before and 8 months after right cranial cruciate ligament transection. There was no significant difference in mean tibial plateau angle before or after induction of osteophytosis. Additionally, it was determined that 90% of dogs had a difference of =2 degrees between right and left tibial plateau angles, which was considered symmetrical.     

Laser-induced ferroelectric structural order in an organic charge-transfer crystal

We report the direct observation by x-ray diffraction of a photoinduced paraelectric-to-ferroelectric structural phase transition using monochromatic 100-picosecond synchrotron pulses. It occurs in tetrathiafulvalene-p-chloranil, a charge-transfer molecular material in which electronic and structural changes are strongly coupled. An optical 300-femtosecond laser pulse switches the material from a neutral to an ionic state on a 500-picosecond time scale and, by virtue of intrinsic cooperativity, generates self-organized long-range structural order. The x-ray data indicate a macroscopic ferroelectric reorganization after the laser irradiation. Refinement of the structures before and after laser irradiation indicates structural changes at the molecular level.     

Xylanase,beta-glucanase,and other side enzymatic activities have greater effects on the viscosity of several feedstuffs than xylanase and beta-glucanase used alone or in combination

This study was carried out to evaluate the effects of a pure xylanase, a pure beta-glucanase, a mix of the two pure enzymes, and a commercial enzyme preparation (Quatrazyme HP, Nutri-Tomen Les Ulis, France) on the viscosity exhibited by water-soluble nonstarch polysaccharides of several feedstuffs (Rialto wheat, Sidéral wheat, Isengrain wheat, triticale, rye, barley, oats, corn, wheat bran, rice bran, wheat screenings, soybean meal, rapeseed meal, sunflower meal, and peas). The viscosity depended on the feedstuffs and varieties of the same feedstuff. There was a correlation (R (2) = 0.86) between viscosity of cereals and their arabinoxylan and beta-glucan contents. The correlation was greater (R (2) = 0.99) when the type of cereal was taken into account. The addition of pure xylanase significantly decreased the viscosity of all feedstuffs except sunflower meal (P < or = 0.05). However, pure beta-glucanase was unable significantly to decrease the viscosity of Isengrain wheat, corn, rice bran, wheat screenings, soybean meal, and sunflower meal. There was a greater decrease in viscosity with the combination of xylanase and beta-glucanase than with addition of xylanase or beta-glucanase alone. This synergistic action of xylanase and beta-glucanase was observed only in Rialto wheat, Sidéral wheat, triticale, rye, barley, oats, and peas. Finally, the commercial enzyme preparation produced a greater reduction (P < or = 0.05) in viscosity for all feedstuffs compared to xylanase or beta-glucanase used alone or in combination. The greater effectiveness of the commercial enzyme preparation was due to the presence of side enzymatic activities (arabinofuranosidase, xylosidase, glucosidase, galactosidase, cellulase, and polygalacturonase).     

Tibiotarsal fracture repair in a bald eagle (Haliaeetus leucocephalus) using an interlocking nail.

A 14-yr-old, 5.13-kg bald eagle (Haliaeetus leucocephalus) was hit by a car and presented to the Michigan State University Small Animal Clinic with an open, grade II, transverse, midshaft, Winquist-Hansen type-II-comminuted left tibiotarsal fracture. The fracture was reduced and fixation established with a 4.7-mm-diameter, 112-mm-long, four-hole veterinary intramedullary interlocking nail maintained in position by single 2-mm transcortical screws placed in the main proximal and distal fragments. The bird was weight bearing on the bandaged limb 48 hr postoperatively. Radiographs obtained 4 wk postoperatively revealed bridging callus over three of four cortices. The bird was released after 5 mo of rehabilitation.     

Effect of some repetitive factors on turbot stress response

The stress response of the turbot, Scopthalmus maximus (L.), to repetitive factors including netting, air exposure, blood sampling and hand-stripping, were tested using two different tank sizes as well as two blood sampling techniques. Exposure of juvenile fish to air for 1-4 min had no immediate effect on plasma cortisol concentrations or haematocrit values. Similarly, the serial netting of immature fish from tanks did not significantly modify plasma cortisol concentrations, haematocrit or osmolarity values. Hand-stripping of mature males was more disturbing than air exposure. The cumulative effect on plasma cortisol levels and osmolarity of stress factors such as netting, air exposure, blood sampling and stripping applied simultaneously to mature males in a 16 m3 tank and repeated twice daily for several days was recorded. The level of cortisol increased from 5 ng ml-1 to 300 ng ml-1 after 10 days of treatment, while an osmoregulatory imbalance and fish death were observed. Moreover, adaptation of fish to smaller tanks seemed to improve the increased plasma cortisol levels and death rate. Reduction in the number of stress factors applied greatly decreased both the range of physiological responses and the death rate. In order to avoid a cumulative stress response, handling of fish should therefore be reduced to a minimum.     

In vitro mechanical evaluation on the use of an intramedullary pin-plate combination for pantarsal arthrodesis in dogs

OBJECTIVE: To compare the biomechanical properties of pantarsal arthrodesis achieved with a dorsal bone plate-alone (BPA) or pin-plate combination (PPC). SAMPLE POPULATION: 8 pairs of cadaver canine tarsi. PROCEDURE: Within a pair, 1 tarsus was arthrodesed by use of a 13-hole 3.5-mm broad dynamic compression bone plate applied to the dorsal aspect of the tarsus; the paired tarsus received an identical plate similarly applied, with the addition of an intramedullary pin filling approximately 40% of the tibial medullary canal, spanning the tibiotarsal joint. Plates were instrumented with strain gauges proximal and distal to the solid portion of the plate. Specimens were mounted on a servo-hydraulic testing machine and loaded at 20%, 40%, and 80% of body weight for 10 cycles at 1 Hz. Construct compliance, angular deformation, and plate strain were determined during the 10th cycle. RESULTS: PPC specimens were less compliant than BPA specimens at all loads and had significantly less angular deformation than BPA specimens at loads of 40% and 80% of body weight. Tibiotarsal gauge microstrain was significantly less in PPC specimens, compared with BPA specimens, regardless of loads. Maximal strains were 33.5% to 40.5% less in PPC than BPA specimens. CONCLUSIONS AND CLINICAL RELEVANCE: For pantarsal arthrodesis in dogs, our results indicate that the PPC construct is biomechanically superior to the BPA construct. By improving construct stability, addition of an intramedullary pin to the traditional BPA technique may lessen implant-related complications and improve plate fatigue life. A subsequent decrease in postoperative morbidity may occur with little addition of time or complexity to the surgical procedure.