A new role for PGRP-S (Tag7) in immune defense: lymphocyte migration is induced by a chemoattractant complex of Tag7 with Mts1

PGRP-S (Tag7) is an innate immunity protein involved in the antimicrobial defense systems, both in insects and in mammals. We have previously shown that Tag7 specifically interacts with several proteins, including Hsp70 and the calcium binding protein S100A4 (Mts1), providing a number of novel cellular functions. Here we show that Tag7–Mts1 complex causes chemotactic migration of lymphocytes, with NK cells being a preferred target. Cells of either innate immunity (neutrophils and monocytes) or acquired immunity (CD4⁺ and CD8⁺ lymphocytes) can produce this complex, which confirms the close connection between components of the 2 branches of immune response.     

Healing of "wire tunnels" in tibial diaphysis: data of local X-ray study and densitometry

Fifteen pelvic extremities from adult dogs were used to perform 60 cross tunnelization of tibial diaphysis with a wire having a pointed groove, 1.8-mm in diameter, at 1,500 rpm. Thirty five leg X-ray films in the lateral projection, which show changes on days 30, 60, 90, 120, 520 after the experiment, were studied. Bony diaphysis tunnelization was found to give rise to a regeneration focus wherein an area of tissue element degradation and an area of introduction of bony fragments into soft tissues were detectable. Changes in the regeneration focus were determined by a response to osseous fragments, which involved the formation of an bony regenerate during a month and to the resorption of the bony matter of an osseous regenerate and osseous fragments in future. Healing of diaphysis defects began with the resorption of a damaged cortical layer. Osteogenesis prevailed at month 2 and ensured healing of cortical layer defects following 4-6 months.     

Changes in hemodynamics of the long bone due to tunnelization under pulsing and non-pulsing pressure in a shaft cavity

In 25 dogs, it was revealed that the pressure in a long bone shaft cavity (IBP) pulsed at relatively high values. According to rheovasography data, the pulse changes of the vascular blood filling of a shaft cavity caused the IBP. The blood filling changes at pulsing IBP produced pulse changes in interstitial fluid amount, at non-pulsing IBP they provided for fluid coming into the interstitial space of the shaft cavity without pulsations. Tunnelization led to appearance of compact substance defect, at the size of which, coming to 2.4% of shaft area, IBP always decreased, remained decreased during 2 months and restored during the third month. The IBP decrease changed the bone hemodynamics.     

Identification of signature and primers specific to genus <Emphasis Type="Italic">Pseudomonas</Emphasis> using mismatched patterns of 16S rDNA sequences

Background

Pseudomonas, a soil bacterium, has been observed as a dominant genus that survives in different habitats with wide hostile conditions. We had a basic assumption that the species level variation in 16S rDNA sequences of a bacterial genus is mainly due to substitutions rather than insertion or deletion of bases. Keeping this in view, the aim was to identify a region of 16S rDNA sequence and within that focus on substitution prone stretches indicating species level variation and to derive patterns from these stretches that are specific to the genus.

Results

Repeating elements that are highly conserved across different species of Pseudomonas were considered as guiding markers to locate a region within the 16S gene. Four repeating patterns showing more than 80% consistency across fifty different species of Pseudomonas were identified. The sub-sequences between the repeating patterns yielded a continuous region of 495 bases. The sub-sequences after alignment and using Shanon's entropy measure yielded a consensus pattern. A stretch of 24 base positions in this region, showing maximum variations across the sampled sequences was focused for possible genus specific patterns. Nine patterns in this stretch showed nearly 70% specificity to the target genus. These patterns were further used to obtain a signature that is highly specific to Pseudomonas. The signature region was used to design PCR primers, which yielded a PCR product of 150 bp whose specificity was validated through a sample experiment.

Conclusions

The developed approach was successfully applied to genus Pseudomonas. It could be tried in other bacterial genera to obtain respective signature patterns and thereby PCR primers, for their rapid tracking in the environmental samples.

     

Meiotic analysis of four cross-pollinated generations in a synthetic autotetraploid population of husk tomato (<i>Physalis ixocarpa</i>)

The cultivated husk tomato (Physalis ixocarpa) (2n = 2x = 24) is native from Mexico and Central America and shows a wide genetic variation. Presently, it is the fourth horticultural crop in cultivation surface in Mexico. The working team of this research previously developed an autotetraploid population by using colchicine. The objectives of the present work were to analyze the ploidy level and meiotic behavior of the subsequent generations (C3, C4, C5, C6) from the original (C2) composed only by plants with the duplicated genome from the Rendidora cultivar, and to determine pollen viability. As a diploid control the cultivar Rendidora of P. ixocarpa was used. Ploidy level was determined by flow citometry and meiotic analysis. For the meiotic study, the microsporocytes were prepared by the squash method, stained with carmin and analyzed in diakinesis. Pollen viability was evaluated through 0.01% Buffalo Black staining. The tetraploid condition prevailed through four cross-pollinating generations, maintaining a constant chromosome number 2n = 4x = 48. In diakinesis, the chromosomes of the diploid cultivar were associated into bivalents, whereas in tetraploid plants the chromosomes associated into univalents, bivalents and trivalents. Highly significant differences in bivalent pairing were detected between autotetraploid plants and between generations. Pollen viability did not show significant differences between generations and allowed reproduction. These results indicate that it is possible to develop an autotetraploid cultivar, because the polyploid state is naturally maintained and the plants are fertile. Furthermore, given the differences in bivalent pairing between plants and generations, a response to selection toward meiotic stability is expected.     

An asymmetric approach to preserve common intervals while sorting by reversals

Background  

The reversal distance and optimal sequences of reversals to transform a genome into another are useful tools to analyse evolutionary scenarios. However, the number of sequences is huge and some additional criteria should be used to obtain a more accurate analysis. One strategy is searching for sequences that respect constraints, such as the common intervals (clusters of co-localised genes). Another approach is to explore the whole space of sorting sequences, eventually grouping them into classes of equivalence. Recently both strategies started to be put together, to restrain the space to the sequences that respect constraints. In particular an algorithm has been proposed to list classes whose sorting sequences do not break the common intervals detected between the two inital genomes A and B. This approach may reduce the space of sequences and is symmetric (the result of the analysis sorting A into B can be obtained from the analysis sorting B into A).     

Study of the mitotic and meiotic chromosomes of sotol (<i>Dasylirion cedrosanum</i> Trel.)

The genus Dasylirion is a group of plants typically present in the Chihuahuan Desert, perennial, with a dioecious sexual behavior and commonly called sotoles. This genus has been little studied from the biological point of view, and the bases of its reproductive response remain unknown. In this work we studied the chromosome number and meiotic response of Dasylirion cedrosanum in the county of Saltillo, Coahuila, located at the North East of Mexico. For the preparation of mitotic chromosomes, we used a technique based on enzymatic treatment with pectolyase and cellulase, as well as staining with acetocarmin dye. For the study of meiosis, male flower buds were collected, fixed and stained for analysis with the same dye. As a result, the gametic (n = x = 19) and somatic chromosome (2n = 38) numbers of D. cedrosanum are reported for the first time, being consistent with previous findings in other Dasylirion species, which points to a constant ploidy level across the genus. Variation was observed in the morphology and size of the somatic chromosomes, with types ranging from submetacentric to subtelocentric, and sizes oscillating in a range of 4.43 µm, with an average total length of 112.38 µm for the diploid chromosome complement. This shows that the chromosome complement of D. cedrosanom would belong to a 3B classification of Stebins, with a medium variation between chromosome lengths and low chromosome asymmetry. This variation indicates the feasibility of constructing a chromosome ideotype for this species. The meiotic chromosome pairing showed a chromosome behavior consistent with a disomic inheritance characteristic of a diploid species, with prevalence of ring and chain bivalents, typically without pairing abnormalities. Bivalent configurations in all cases were symmetrical.The normal and symmetrical meiotic pairing indicates a balanced production of gametes, and suggests the absence of heteromorphic sex determination.     

The interrelationship between compact tissue defect and bone shaft cavity circulation

The intraosseous pressure of tissue fluid, the electrical resistance between electrodes and the parameters of hemodynamics in tibial shaft cavity were measured experimentally. It was established that the occurrence and increase of compact defects led to the enhancement of fluid filtration from capillaries and tissue blood filling, whereas the reduction of compact defects led to hemodynamics parameter decrease. The shunting influence of newly formed regenerate bone capillaries cause an arterial wall elasticity increase and volumetric circulation rate limitation. The filtration-and-resorption balance of bone shaft cavity restored and circulation enhanced after compact defect healing.     

Effect of Ilizarov tibial lengthening on limb blood flow

The experiment in 23 adult dogs was based on the study of volumetric blood flow velocity in the superficial femoral artery and femoral vein, pulse changes in blood filling of the m. gastrocnemius in the conditions of tibial lengthening to 17.5-23% from the initial length. Complex changes in the blood flow parameters were revealed after surgical intervention and within 7 distraction days. When the distraction ended, the volumetric blood flow velocity in the femoral artery was reduced by 19% and the blood flow out of the vessel was improved by 17%. When fixation was over, the volumetric blood flow velocity in the vessel increased by 37% and the improved outflow preserved. At each experimental stage, there was an increased volumetric blood flow velocity in the femoral vein as compared to its value in the control group, its correspondence to the superficial femoral artery as well as similar dynamics in blood flow changes in the femoral vessels and m. gastrocnemius. The findings show that the vascular system of bone regeneration provides accelerated arterial blood transportation into the venous system during organotypical bone area formation.     

The timing of alpha-gustducin expression during cell renewal in rat vallate taste buds

The G protein subunit alpha-gustducin is expressed in a subset of light (Type II) but not in dark (Type I) cells in rat vallate taste buds. The thymidine analogue 5-bromo-2'-deoxyuridine (BrdU) is incorporated into DNA during the S-phase of the cell cycle and can be used to determine the time of origin of a cell. In this study, 31 rats were injected with BrdU (50 mg/kg i.p.) and perfused at various times, from 2.5 to 10.5 days, following BrdU administration. Vallate papillae were embedded in polyester wax, cut into 4 microm transverse sections, and characterized with antibodies to BrdU and alpha-gustducin. Sections were processed for indirect immunofluorescence or with an immunoperoxidase procedure. From immunoperoxidase material on 21 rats, counts of alpha-gustducin- and BrdU-labeled cells were obtained from 300-800 taste bud profiles at each survival time; a total of 4122 taste bud profiles were examined. Cells with nuclei immunoreactive for BrdU occurred within the taste buds at 2.5 days and double-labeled cells were clearly evident at 3.5 days; a small number of double-labeled cells were seen as early as 2.5 days. Double-labeled cells reached a peak at 6.5 days and did not decline significantly by 10.5 days. Cells labeled for BrdU but not alpha-gustducin peaked at 5.5 days and showed a significant decline by 8.5 days. These latter cells included light cells not expressing alpha- gustducin and dark cells, which have previously been shown to have a shorter life span than light cells. These data suggest that expression of alpha-gustducin appears very early in a cell's life span and that these cells are longer lived than many of the cells that do not express this G protein.