Intact Tail Research Articles

Gene Expression Profiles Perturbed by Injury to the Mouse Intervertebral Disc.

Back pain subsequent to intervertebral disc (IVD) injury is a common clinical problem. Previous work examining early molecular changes post injury mainly used a candidate marker approach. In this study, gene expression in the injured and intact mouse tail IVDs was determined with a nonbiased whole transcriptome approach. Mouse tail IVD injury was induced by a needle puncture. Whole murine transcriptome was determined by RNASeq. Transcriptomes of injured IVDs were compared with those of intact controls by bioinformatic methods. Among the 18,078 murine genes examined, 592 genes were differentially expressed (P.adj < 0.01). Novel genes upregulated in injured compared with intact IVDs included Chl1, Lum, etc. Ontology study of upregulated genes revealed that leukocyte migration was the most enriched biological process, and network analysis showed that Tnfa had the most protein-protein interactions. Novel downregulated genes in the injured IVDs included 4833412C05Rik, Myoc, etc. The most enriched downregulated pathways were related to cytoskeletal organization. Novel genes highly regulated post disc injury were identified with an unbiased approach; they may serve as biomarkers of injury and response to treatments in future experiments. Enriched biological pathways and molecules with high numbers of connections may be targets for treatments post injury.

Structure of the intact tail machine of Anabaena myophage A-1(L)

The Myoviridae cyanophage A-1(L) specifically infects the model cyanobacteria Anabaena sp. PCC 7120. Following our recent report on the capsid structure of A-1(L), here we present the high-resolution cryo-EM structure of its intact tail machine including the neck, tail and attached fibers. Besides the dodecameric portal, the neck contains a canonical hexamer connected to a unique pentadecamer that anchors five extended bead-chain-like neck fibers. The 1045-Å-long contractile tail is composed of a helical bundle of tape measure proteins surrounded by a layer of tube proteins and a layer of sheath proteins, ended with a five-component baseplate. The six long and six short tail fibers are folded back pairwise, each with one end anchoring to the baseplate and the distal end pointing to the capsid. Structural analysis combined with biochemical assays further enable us to identify the dual hydrolytic activities of the baseplate hub, in addition to two host receptor binding domains in the tail fibers. Moreover, the structure of the intact A-1(L) also helps us to reannotate its genome. These findings will facilitate the application of A-1(L) as a chassis cyanophage in synthetic biology.

Molecular recognition of ITIM/ITSM domains with SHP2 and their allosteric effect.

Src homology 2-domain-containing tyrosine phosphatase 2 (SHP2) is a non-receptor protein tyrosine phosphatase that is widely expressed in a variety of cells and regulates the immune response of T cells through the PD-1 pathway. However, the activation mechanism and allosteric effects of SHP2 remain unclear, hindering the development of small molecule inhibitors. For the first time, in this study, the complex structure formed by the intact PD-1 tail and SHP2 was modeled. The molecular recognition and conformational changes of inactive/active SHP2 versus ITIM/ITSM were compared based on prolonged MD simulations. The relative flexibility of the two SH2 domains during MD simulations contributes to the recruitment of ITIM/ITSM and supports the subsequent conformational change of SHP2. The binding free energy calculation shows that inactive SHP2 has a higher affinity for ITIM/ITSM than active SHP2, mainly because the former's N-SH2 refers to the α-state. In addition, a significant decrease in the contribution to the binding energy of certain residues (e.g., R32, S34, K35, T42, and K55) of conformationally transformed SHP2 contributes to the above result. These detailed changes during conformational transition will provide theoretical guidance for the molecular design of subsequent novel anticancer drugs.

К вопросу о половых различиях метрических признаков у колхидской веретеницы Anguis colchica (Nordmann in Demidoff, 1840) (Anguidae, Reptilia)

The length of the body without a tail (L.) and the length of an intact tail (L. cd.) were measured in 91 males and 110 females of Anguis colchica from the Chamzinsky rayon of the Republic of Mordovia. A comparative analysis of three morphometric characters (L., L. cd., L. / L. cd.) of males and females was carried out with the construction of variation series and using the frequency approach. Range of variability of L. and L. cd. (from 120 to 279 mm) were divided into eight classes, of which, according to body length without the tail, males were represented in seven, females in eight classes; According to the length of the tail, males were represented in six, and females in eight classes. Tail length depended on body length in males (r = 0.903, p &lt; 0.001, R2 = 0.81) and females (r = 0.925, p &lt; 0.001, R2 = 0.857). The proportions of males and females with a body length of 159 mm and less in the sample did not differ (p = 0.337), in the average size classes (from 160 to 199 mm) males predominated (p = 0.05), in size classes greater than 220 mm – females (p = 0.021). In the size class 200–219 mm, long-tailed females predominated.

Recovery and Characterization of Spermatozoa in a Neotropical, Terrestrial, Direct-Developing Riparian Frog (Craugastor evanesco) through Hormonal Stimulation.

The Vanishing Rainfrog (Craugastor evanesco) is an endemic and critically endangered frog species of Panama. It is suspected that 90% of the population has disappeared from the wild. Frogs were collected from the wild and brought to a Captive Breeding Program; however, accomplishing regular reproductive events for this species has been difficult. The objective of this study was to determine the effect of hormonal stimulation on the production and quality of C. evanesco spermatozoa, aiming to develop an efficient and safe sperm collection protocol as a tool to help reproduce this endangered species. Mature males received intra-peritoneal injections with one of six hormone treatments, including des-Gly10, D-Ala6, Pro-NHEt9-GnRH-A, Amphiplex or hCG. Urine samples were collected at 10 different time points post-injection. Quality assessments included sperm concentration, percentage motility, percentage forward progressive motility (FPM), osmolality, pH and morphology analysis. Our results indicate that the optimal treatment for the collection of highly concentrated sperm samples of C. evanesco is 4 µg/gbw GnRH, followed by Amphiplex and 2 µg/gbw GnRH as sub-optimal treatments and finally, 6 µg/gbw GnRH and 5 and 10 IU/gbw hCG as non-optimal treatments. GnRH-A at 4 μg/gbw and Amphiplex stimulated the production of samples with the highest sperm concentrations and quality, despite Amphiplex producing lower percentages of intact acrosome and tail. In contrast, hCG concentrations were not reliable inducers of sperm production, consistently showing lower concentrations, higher percentages of sperm abnormalities and more acidic spermic urine than that induced by Amphiplex and GnRH-A. Morphological assessments revealed that C. evanesco spermatozoa have a filiform shape with a large acrosome on the anterior part of an elongated head, a small midpiece and a long tail with two filaments joined together by an undulating membrane.

Periostin modulates extracellular matrix behavior in tendons

Periostin, originally named osteoblast-specific factor 2 (OSF-2) has been identified primarily in collagen rich, biomechanically active tissues where its role has been implicated in mechanisms to maintain the extracellular matrix (ECM), including collagen fibrillogenesis and crosslinking. It is well documented that periostin plays a role in wound healing and scar formation after injury, in part, by promoting cell proliferation, myofibroblast differentiation, and/or collagen fibrillogenesis. Given the significance of periostin in other scar forming models, we hypothesized that periostin will influence Achilles tendon healing by modulating ECM production. Therefore, the objective of this study was to elucidate the effects of periostin during Achilles tendon healing using periostin homozygous (Postn−/−) and heterozygous (Postn+/-) mouse models. A second experiment was included to further examine the influence of periostin on collagen composition and function using intact dorsal tail tendons. Overall, Postn−/− and Postn+/- Achilles tendons exhibited impaired healing as demonstrated by delayed wound closure, increased type III collagen production, decreased cell proliferation, and reduced tensile strength. Periostin ablation also reduced tensile strength and stiffness, and altered collagen fibril distribution in the intact dorsal tail tendons. Achilles tendon outcomes support our hypothesis that periostin influences healing, while tail tendon results indicate that periostin also affects ECM morphology and behavior in mouse tendons.

De novo transcriptome profile of two earthworms Lampito mauritii and Drawida calebi during regeneration

Earthworms have remarkable ability to regenerate its tail and head region. However the list of genes expressed in this regeneration process has been less explored baring a few species. The current study involves the de novo transcriptome sequencing of intact tail and regenerating tail (15 day post amputation) of earthworms belonging to two different genera Lampito mauritii (Kinberg, 1867) and Drawida calebi (Gates, 1945). This study contains one de-novo and one reference based transcriptome analysis each from one genus of two earthworm genera. From a total of 119.92 million (150 × 2) reads, 112.95 million high quality adapter free reads were utilized in analysis. Assembly of high-quality reads was performed separately for Lampito mauritii (LM sample) and Drawida calebi (DC sample) that resulted in 66368 and 1,61,289 transcripts respectively. About 25.21% of transcripts were functionally annotated for DC sample and 38.27% for LM samples against Annelida sequences. A total of 239 genes were expressed exclusively in regenerated tissue compared to intact sample in DC whereas about 241 genes were exclusively expressed in regenerated tissue of LM compared to its intact sample. Majority of genes in Drawida and Lampito were dedicated to immune response, maintenance of cytoskeleton, resisting oxidative stress and promoting neuronal regeneration for cell-cell communication during tail regeneration.

Provision of straw and the presence of undocked lambs reduce the behavioural and physiological expressions of pain and stress associated with tail docking in lambs: a preliminary study

Aims The aim of this experiment was to determine if the provision of straw and the presence of undocked twins could be used to mitigate the pain experienced by lambs having their tails docked using rubber rings. Methods A total of 54 twin St. Croix 60-days-old weaned lambs were assigned to one of four treatments: (i) the presence of undocked twins and no provision of straw (U); (ii) the provision of straw and no presence of undocked twins (St); (iii) the provision of straw and the presence of undocked twins (StU); and (iv) no provision of straw and no presence of undocked twins (C). Straw was provided as bed material over the concrete floor; whereas the presence of undocked twins was achieved by leaving one twin intact within each pair. From the placement of the rubber rings, the behaviour of tail-docked twins was video recorded continuously for 60 min, and blood samples were taken from these lambs immediately before placing the rubber ring (time 0), and at 0.5, 1, 1.5, 24, 48 and 72 h after, for cortisol and physio-metabolic profiles determination, and at 168 h after, for cortisol determination. Key results Lambs in treatment C spent three times longer in abnormal lying postures (P = 0.002) compared with St and StU lambs (6.49 ± 4.73 vs 1.78 ± 1.26 and 1.83 ± 1.94 min respectively). Lambs in all treatments experienced an increase in cortisol levels 1 h after tail docking, except for StU lambs. In addition, 48 and 72 h after tail docking, lambs in treatments St and StU had lower concentrations of cortisol than C lambs. Conclusion This study shows that the provision of straw and the presence of undocked twins reduce the behavioural and physiological expressions of pain associated with tail docking in lambs. Implications In lambs raised under intensive conditions, the addition of straw as bedding material and the presence of intact tail lambs could be a practical strategy to improve the welfare of tail-docked lambs, whereas for those lambs raised under extensive conditions, leaving intact those lambs that will be sold might serve as social buffering for their tail-docked conspecifics that will remain in the farm.

Intact Tails as a Welfare Indicator in Finishing Pigs? Scoring of Tail Lesions and Defining Intact Tails in Undocked Pigs at the Abattoir.

Tail biting lesions are a potential measure of on-farm animal welfare, as a large range of stressors increase the risk for tail biting outbreaks. Further, tail biting is a major challenge, as lesions due to tail biting decrease animal welfare and health, as well as production efficiency and carcass quality. The aim of this study was to suggest a tail scoring system for use at slaughterhouses processing undocked pigs, and to link tail lesion scores to meat inspection data. A further aim was to suggest a definition for an intact enough tail. To validate the suggested scoring system we assessed tails before and after scalding and compared results to pathological examinations. In total, 14,433 tails were scored, and 117 tails were collected for pathological examination. After scalding, 49.2% of all tails were scored as fully intact. Of tails with lesions 2.5% were scored as having major acute wounds (>2 cm), while 11.6% had minor acute wounds (<2 cm), and 36.7% healed lesions. Intact tails were on average 31.5 cm (SD 2.5 cm) long. Lesion scored at the slaughter-line agreed well with the pathological assessment. Tail lesions were associated with several meat inspection findings: tails with more severe lesions and of shorter length increased the risk for meat inspection findings to a higher degree. A detailed lesion scoring method helps to identify carcasses at risk for condemnations, as well as being a potential method for on-farm welfare estimation. We suggest that a system for scoring tail lesions in undocked pigs should utilize a combination of scoring of the lesion and measuring the tail length. As bite marks or bruises on an otherwise intact tail were not a concern for meat hygiene, we suggest the definition of an intact enough tail could allow the inclusion of tails with these mild changes. Meat inspection findings in carcasses with tails scored as healed, but with no fresh lesions, and with more than 75% of the average intact length remaining were rather similar to those of fully intact tails. Based on these findings we suggest that a tail of this length, and with no visible fresh lesions could also be considered intact enough.

Effect of tail fin loss on swimming capability and tail beat frequency of juvenile black carp Mylopharyngodon piceus

Fin clipping is a common practice in fisheries management, and hatchery fish are often marked this way. In the wild, the tail (caudal) fin may be damaged or lost to predation or disease. Because the tail fin is important to fish swimming behavior and ability, this study was designed to examine the effects of partial and complete loss of the tail fin on the swimming ability of juvenile black carpMylopharyngodon piceus. Swimming speed and tail beat frequency were measured for 3 groups (intact tail fin, partial tail fin, no tail fin) using a stepped velocity test conducted in a fish respirometer. We found that critical swimming speed (Ucrit) and burst speed (Uburst) decreased slightly in the partial fin group and significantly in the no fin group. In the group with no tail fin, Uburstdecreased more than Ucrit, clearly reducing the ability to avoid predators. Moreover, mean tail beat frequency (TBFmean), Ucritand Uburstall decreased slightly in the partial fin group and significantly in the no fin group. A decrease in tail beat force and TBF both reduce swimming capability. These findings contribute to developing our understanding of the relationship between fish tail fins and swimming.

Effects of tail docking and/or teeth clipping on behavior, lesions, and physiological indicators of sows and their piglets

To evaluate effects of tail docking and/or teeth clipping on sows and their piglets, a total of 24 sows and their 302 piglets at 3days of age were randomly allocated to one of four treatments: teeth clipping and tail docking (TCTD), teeth clipping (TC), tail docking (TD), or intact teeth and tail (Intact). Behavior of piglets and sows, lesions on the body and tail of piglets and sows' teats were inspected. Heart rates of processed piglets were increased (p<.01) during the procedures. Teeth clipping decreased body surface temperature (p<.01) of piglets during and after the procedures but tail docking did not (p>.01). Processed piglets spent more (p<.05) time lying alone and playing/fighting than sham-processed piglets. Tail docked piglets spent less (p<.01) time standing than tail sham-docked piglets. Intact teeth increased (p<.05) the avoidance behaviors of sows. Teeth clipping decreased (p<.05) the lesion scores on the anterior, middle, and posterior teats. Taken together, piglet teeth clipping had more impact on sows and their piglets than tail docking did in the lactation period based on our findings.

Experimental study on submerged supersonic gaseous jet induced tail cavity

Multiphase jets and cavitation problems are inevitable for high-speed underwater vehicles propelled by jet engines. Unlike being injected into stagnant water, the gaseous jet behind a underwater vehicle is usually conjugated with a tail cavity. The pulsation and collapse of such cavities can seriously affect the vehicle performance. In this study, the shape character, forming mechanism and control conditions for the supersonic gaseous jet induced tail cavity at the wake of a revolution body are experimentally investigated in a water tunnel. The induced cavity is ventilated only by a convergent-divergent nozzle with a designed Mach number of 2.45. The form of the cavity is recorded through two high-speed cameras both horizontally and vertically under different Froude numbers and ventilation rates. The time averaged form is thus obtained through digital image processing to eliminate the transient characteristics of the cavity. The experiment is conducted with the Froude number ranging from 3.2 to 16.2, and the ventilation rate 0 to 0.5. Due to the high density and velocity ratio between water and gas, the structure of such flow is usually very complicated. Many novel phenomena of the jet-cavity interaction are observed. With increasing stagnation pressure of the central jet, the induced cavities evolves form foamy, intact, partially break, to pulsating foamy closure type. The foamy and intact tail cavities share the same profile and characteristics that of a supercavity. And the pulsating foamy closure type was never observed before in a traditional supercavitating flow. The outline of the pulsating foamy cavity is the same as the foamy cavity's, indicating that they have the similar forming mechanism. A comparison with the jet-cavity interaction model is made and the following conclusions are obtained:the real ventilation rate, which corresponds to the re-entrant jet gas blocked by the cavity boundary, is the key factor in controlling the cavity form. When the gaseous jet is completely blocked by the water-gas interface, an intact or foamy cavity will be formed. A partially break cavity appears only when some fraction of the jet is blocked and this is when some of the strongest interactions between jet and cavity occurs. When little gas was blocked by the interface, a pulsating foamy cavity forms. With the structure of gaseous jet considered, the transition of the induced cavity closure between different types is in favour of the prediction from Paryshev's model of cavity closure to a central jet. The variation of the cavity form, thus the interaction strength between jet and cavity, coincides with the real ventilation rate estimated through the theoretical model.

Migrated prawn tail presenting as neck swelling

Accidental ingestion of food-based foreign body such as fish bones and meat boluses are common among adults. Cases of migrated foreign bodies particularly the sharp-edged ones are also frequently encountered. The presentations of migrated foreign bodies in the neck can initially be asymptomatic and subsequently patients will come with complaint of foreign body or sharp pricking sensation on swallowing, odynophagia, fever or neck swelling. We report a case of a 61-year-old Chinese gentleman who presented with painful left neck swelling with history of eating prawn including its tail 2months prior to presentation. He was symptoms free after eating few boluses of rice since then. With positive findings on imaging studies, the neck lesion was successfully excised under local anesthesia. It contained a migrated intact prawn tail. In conclusion, accidental foreign body ingestion is not uncommon among adults. It is very important to elicit history of foreign body ingestion even in a patient presenting with neck swelling. Besides, oral and neck examination, other investigation modalities such as plain neck radiograph, ultrasonography or computed tomography scan can confirm the diagnosis of migrating foreign bodies and appropriate treatment can be instituted.

Application of a handheld Pressure Application Measurement device for the characterisation of mechanical nociceptive thresholds in intact pig tails

The assessment of nociceptive thresholds is employed in animals and humans to evaluate changes in sensitivity potentially arising from tissue damage. Its application on the intact pig tail might represent a suitable method to assess changes in nociceptive thresholds arising from tail injury, such as tail docking or tail biting. The Pressure Application Measurement (PAM) device is used here for the first time on the tail of pigs to determine the reliability of the methods and to provide novel data on mechanical nociceptive thresholds (MNT) associated with four different age groups (9, 17, 24 and 32weeks) and with proximity of the target region to the body of the animal. We recorded an overall acceptable level of intra-individual reliability, with mean values of CV ranging between 30.1 and 32.6%. Across all age groups, the first single measurement of MNT recorded at region 1 (proximal) was significantly higher (P<0.05) than the following two. This was not observed at tail regions 2 and 3 (more distal). Age had a significant effect (P<0.05) on the mean thresholds of nociception with increasing age corresponding to higher thresholds. Furthermore, a significant effect of proximity of tail region to the body was observed (P<0.05), with MNT being higher in the proximal tail region in pigs of 9, 17 and 24weeks of age. There was also a significant positive correlation (P<0.05) between mechanical nociceptive thresholds and age/body size of the animals.To the best of our knowledge, no other investigation of tail nociceptive thresholds has been performed with the PAM device or alternative methods to obtain mechanical nociceptive thresholds in intact tails of pigs of different age/body size. The reliability of the data obtained with the PAM device support its use in the measurement of mechanical nociceptive threshold in pig tails. This methodological approach is possibly suitable for assessing changes in tail stump MNTs after tail injury caused by tail docking and biting.

Annulus Fibrosus Repair using Genetically Engineered Silk and Genipin-Enhanced Fibringel

Introduction Almost 80% of the population suffers from low back pain at least once in their life causing a high socio economic burden. Often these pains originate from a trauma resulting in disc herniation and /or disc degeneration. Despite this high prevalence and associated costs, a satisfying treatment method is not yet on the market. Here we aimed to develop a new method to seal and repair annulus fibrosus (AF) injuries by using genetically engineered silk carrying GDF-6 a growth factor known to lead stem cells toward an intervertebral disc (IVD)-like phenotype and a genipin-enhanced fibrin hydrogel.1 Materials and Methods Bovine IVDs of 14–17 month old animals were harvested under aseptic conditions.2 After inducing an injury by a circular 2mm biopsy punch (Polymed, Switzerland) the defect was filled up with a commercial human based fibrin hydrogel (Baxter Tisseel, Switzerland) enhanced with 4.2mg/ml of the cross linker genipin (Wako Chemicals GmbH, Germany). For closure and acceleration of repair a silk membrane-fleece composite (Spintec Engineering GmbH, Germany) was put on the defect and hold in place by the hydrogel. After 15 minutes allowing for cross linking in vitro organ culture of bIVDs started for 14 days under three different loading schemes 1) dynamic load 0.2MPa load and ±2° torsion at 0.2Hz for 8h/day 2) static diurnal load of 0.2MPa or 3) free swelling. For dynamic loading a custom built two-degree of freedom bioreactor was used.3 At the end of culture discs were checked for seal failure by the eye, disc height, metabolic activity (alamar blue), cell death by necrosis (LDH assay) and apoptosis (Caspase 3/7), DNA, GAG and collagen content (via hydroxyl proline = HYP) and RT-qPCR was performed. Results Throughout the 14 days of culture the silk composite maintained its position under all three loading schemes. Although repaired discs performed slightly lower in alamar blue, DNA and GAG content were in the range of the control. Also LDH resulted in similar values compared with control discs. Height loss in repaired discs was in the same range of static diurnal loaded control samples. Dynamically loaded discs decrease to the level of injured, unrepaired discs. In general discs suspended to dynamic loading showed slightly higher expression of inflammation marker genes measured relative to control discs when compared with free swelling samples. Conclusion Silk-genipin-fibrin reinforced hydrogel is a promising approach to close AF defects as instant loading was possible and composite remained on its position. Further experiments focus on cytocompatibility of genipin-enhanced fibrin hydrogel and organ culture of silk containing covalently linked growth factors. Acknowledgments This project is funded by the Gebert Rüf Stiftung project # GRS-028/13. References Clarke LE, McConnell JC, Sherratt MJ, Derby B, Richardson SM, Hoyland JA. Growth differentiation factor 6 and transforming growth factor-beta differentially mediate mesenchymal stem cell differentiation, composition, and micromechanical properties of nucleus pulposus constructs. Arthritis Res Ther 2014;16(2):R67 Chan SC, Gantenbein-Ritter B. Preparation of intact bovine tail intervertebral discs for organ culture. J Vis Exp 2012;60(60):e3490 Walser J, Ferguson SJ, Gantenbein-Ritter B. Design of a mechanical loading device to culture intact bovine caudal motional segments of the spine under twisting motion. In: Davies J, ed. Replacing Animal Models: A Practical Guide to Creating and Using Biomimetic Alternatives. Chichester, UK: John Wiley &amp; Sons Ltd.; 2012:89–105

Non-invasive measurement of melanin-derived radicals in living mouse tail using X-band EPR.

The aim of this experiment is to measure in vivo generation of melanin-derived radicals non-invasively, as a quantifiable index of radio-biological effect. Melanin-derived radicals in a living intact mouse tail tip were non-invasively measured in very simple way using an X-band electron paramagnetic resonance spectrometer. Colored mouse strains, C57BL/6NCr, BDF1, and C3H/He, have clear EPR signal corresponding to melanin-derived radicals in the tail tip; however, albino mouse strains, BALB/cCr, ddY, ICR, have no EPR signals. An X-ray fraction of 2 Gy/day (1 Gy/min) was repeatedly irradiated to a C3H/He mouse tail skin every Monday to Friday for 4 weeks. In comparison to before starting irradiation, the C3H/He mouse tail skin became darker, like a suntan. The melanin-derived radicals in C3H/He mouse tail skin were increased in association with X-ray fractions. Melanin-derived radicals in mouse tail skin can be readily and chronologically measurable by using X-band EPR spectrometer, and can be a marker for a radiobiological effect in the skin.

Functional role of the C-terminal tail of the archaeal ribosomal stalk in recruitment of two elongation factors to the sarcin/ricin loop of 23S rRNA.

Two types of elongation factors alternate in their binding to the factor-binding center of the ribosome. Both binding events are accompanied by GTP hydrolysis and drive the translation elongation cycle. The multicopy ribosomal protein family, termed the stalk, contributes actively to the elongation process. Recent evidence indicates that the mobile C-terminal tail of archaeal stalk aP1 directly interacts with both the elongation factors aEF1A and aEF2. To investigate the functional significance of these interactions in recruitment of elongation factors to the factor-binding center of the ribosome, we substituted the archaeal stalk complex aL10•aP1 for the bL10•bL12 stalk complex in the Escherichia coli 50S subunit. The resultant hybrid ribosome accessed archaeal aEF1A and aEF2 in a manner dependent on the C-terminal tail containing the hydrophobic residues Leu103, Leu106 and Phe107. Bases G2659 and A2660 in the sarcin/ricin loop (SRL) of 23S rRNA were protected against DMS modification by both factors as was A1067 by aEF2. Mutagenesis indicated that this protection was dependent on the intact C-terminal tail of aP1. The results suggest a crucial role for the interactions between the stalk C-terminal tail and elongation factors in their recruitment to the SRL of 23S rRNA within the ribosome.

Coherent X-Ray Imaging of Collagen Fibril Distributions within Intact Tendons

The characterization of the structure of highly hierarchical biosamples such as collagen-based tissues at the scale of tens of nanometers is essential to correlate the tissue structure with its growth processes. Coherent x-ray Bragg ptychography is an innovative imaging technique that gives high resolution images of the ordered parts of such samples. Herein, we report how we used this method to image the collagen fibrillar ultrastructure of intact rat tail tendons. The images show ordered fibrils extending over 10–20 μm in length, with a quantifiable D-banding spacing variation of 0.2%. Occasional defects in the fibrils distribution have also been observed, likely indicating fibrillar fusion events.

Locomotor performance of sand lizards (Lacerta agilis): effects of predatory pressure and parasite load

Locomotor performance affects foraging efficiency, predator avoidance and consequently fitness. Agility and speed determine the animal's social status and reflect its condition. In this study, we test how predatory pressure and parasite load influences locomotor performance of wild specimens of the sand lizard Lacerta agilis. Animals were chased on a 2-metre racetrack. Lizards with autotomy ran significantly faster than lizards with an intact tail, but there was no significant difference in running speed between individuals with fresh caudal autotomy and regenerated tails. Parasite presence and load, age and sex had no significant effect on speed. Our results indicate that autotomy either alters locomotory behaviour or that individuals with autotomised tails were those that previously survived contact with predators, and therefore represented a subgroup of the fastest individuals. Therefore, in general, predatory pressure but not parasites affected locomotor performance in lizards.

Spatial and temporal characteristics of Ca2+ signaling in endothelial cells of intact rat tail artery

Very few studies have described briefly the spatial and temporal characteristics of Ca2+ signaling using ATP, bradykinin, histamine and thrombin in cultured endothelium. However so far, the spatial and temporal characteristics in intact endothelium have not been elucidated.The aim of this work was to increase the understanding of characteristics of Ca2+ signaling in endothelial cells using real time confocal imaging of Fluo-4 loaded intact rat tail arteries. Of all the three agonist used i.e. histamine, bradykinin and carbachol; only CCh produced strong dose dependent stimulant action on the endothelial cells of intact rat tail artery. Local endothelial heterogeneity was observed in fresh intact cells in response to the three agonist used which was absent upon culture.In agreement with the previous studies, each of the three agonists produced complex Ca2+ signaling consisting of initial fast followed by sustained component with Ca2+ oscillations superimposing it. The data supports the following conclusions: (i) Ca2+ puffs were evoked in 18% and 14% of cells by low concentrations of CCh (0.1 μM and 1 μM), respectively. The average diameter and width of Ca2+ puffs initiation sites was 1.9 ± 0.4 μm, 1.6 ± 0.1 μm, respectively. Length varied between 2 and 6 μm (n = 25 vessels). (ii) ECs responding with Ca2+ waves and oscillations were dependent on concentration of CCh: 0.1 μM (20%), 1 μM (65%) and 10 μM (99%). Speed of wave propagation and frequency of Ca2+ oscillations varied among different cells even at the same agonist concentration. (iii) Ca2+ waves were regenerative; initiated by one or both ends of the cell and propagated across the cell at a speed of 14–44 μm/s (iv) With increasing concentrations of CCh (0.1–10 μM), the frequency of Ca2+ oscillations ranged from 0.02 to 0.3 Hz with optimal frequency being about 0.2 ± 0.02 Hz (n = 15 vessels). In conclusions, this data shows the morphology, heterogeneity and detailed characteristics of Ca2+ signal in intact endothelial cells.