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A test of sensory bias for long tails in the house finch.

The sensory bias model of sexual selection proposes that female preferences for certain male traits result from biases in the female sensory system that existed prior to the evolution of the preferred trait. Phylogenetic tests of the sensory bias hypothesis have provided evidence for pre-existing bias in several species, but the hypothesis has not been tested relative to elongated tail feathers, a widespread sexually selected trait in birds. Elongated tails occur sporadically across avian taxa, including cardueline finches (family Fringillidae), suggesting that long tails evolved independently in many lineages. To determine whether a female preference for longer tails predated the evolution of long tails in cardueline finches, we tested female preferences for artificially lengthened tail feathers in male house finches, Carpodacus mexicanus. The house finch is a cardueline finch species with a tail that does not appear to be elongated or sexually selected. In mate choice experiments, females did not demonstrate a preference for lengthened tails over controls. This negative result fails to support the hypothesis that elongation of tail feathers resulted from exploitation of a widespread sensory bias. Copyright 1998 The Association for the Study of Animal Behaviour.

Journal Article↗

Three amphioxus Wnt genes (AmphiWnt3, AmphiWnt5, and AmphiWnt6) associated with the tail bud: the evolution of somitogenesis in chordates.

The amphioxus tail bud is similar to the amphibian tail bud in having an epithelial organization without a mesenchymal component. We characterize three amphioxus Wnt genes (AmphiWnt3, AmphiWnt5, and AmphiWnt6) and show that their early expression around the blastopore can subsequently be traced into the tail bud; in vertebrate embryos, there is a similar progression of expression domains for Wnt3, Wnt5, and Wnt6 genes from the blastopore lip (or its equivalent) to the tail bud. In amphioxus, AmphiWnt3, AmphiWnt5, and AmphiWnt6 are each expressed in a specific subregion of the tail bud, tentatively suggesting that a combinatorial code of developmental gene expression may help generate specific tissues during posterior elongation and somitogenesis. In spite of similarities within their tail buds, vertebrate and amphioxus embryos differ markedly in the relation between the tail bud and the nascent somites: vertebrates have a relatively extensive zone of unsegmented mesenchyme (i.e., presomitic mesoderm) intervening between the tail bud and the forming somites, whereas the amphioxus tail bud gives rise to new somites directly. It is likely that presomitic mesoderm is a vertebrate innovation made possible by developmental interconversions between epithelium and mesenchyme that first became prominent at the dawn of vertebrate evolution.

Animals↗

Efficacy of pheromone-acaricide-impregnated tail-tag decoys for controlling the bont tick, Amblyomma hebraeum (Acari: Ixodidae), on cattle in Zimbabwe.

A large-scale field test using pheromone-acaricide-impregnated plastic tail-tag decoys demonstrated excellent efficacy of these devices for control of the bont tick, Amblyomma hebraeum, on cattle in Zimbabwe. The tail tags were impregnated with a mixture containing o-nitrophenol, methyl salicylate, 2,6-dichlorophenol and phenylacetaldehyde and one of three different acaricides (cyfluthrin, flumethrin or alphacypermethrin). o-Nitrophenol and methyl salicylate are components of the A. hebraeum attraction-aggregation-attachment pheromone, while 2,6-dichlorophenol and phenylacetaldehyde are proven attractants for this tick. Both o-nitrophenol and methyl salicylate were lost gradually from the tags over 12 and 14 week periods, respectively. In field trials, tick counts were compared between cattle that received tail tags either impregnated with pheromone mixture alone, cyfluthrin and pheromone mixture, flumethrin and pheromone mixture, alphacypermethrin and pheromone mixture or were left untreated. During the first 3 month trial period, control of adult bont ticks was 94.9% with cyfluthrin tail tags and 87.5% with flumethrin tail tags. In general, there was no significant difference in bont tick numbers on cattle without tags and those with tail tags containing pheromone only. When the trial was repeated for another 3 month period, control of bont ticks with tail tags containing cyfluthrin and flumethrin was 99.3 and 95.1%, respectively. However, control of bont ticks using alphacypermethrin was only 79.2%. Overall, retention of tail tags was excellent although some loss was encountered during the rainy season. In addition to controlling bont ticks, the tail tags provided moderate control of other tick species (Rhipicephalus evertsi evertsi, Rhipicephalus zambeziensis and Hyalomma spp.) simultaneously infesting cattle in the trials.

Animals↗

Mineralogical and geochemical characterization of arsenic in an abandoned mine tailings of Korea.

The mineralogical and chemical characteristics of As solid phases in arsenic-rich mine tailings from the Nakdong As-Bi mine in Korea was investigated. The tailings generated from the ore roasting process contained 4.36% of As whereas the concentration was up to 20.2% in some tailings from the cyanidation process for the Au extraction. Thin indurated layers and other secondary precipitates had formed at the surfaces of the tailings piles and the As contents of the hardened layers varied from 2.87 to 16.0%. Scorodite and iron arsenate (Fe3AsO7) were the primary As-bearing crystalline minerals. Others such as arsenolamprite, bernardite and titanium oxide arsenate were also found. The amorphous As-Fe phases often showed framboidal aggregates and gel type textures with desiccation cracks. Sequential extraction results also showed that 55.7-91.1% of the As in tailings were NH(4)-oxalate extractable As, further confirmed the predominance of amorphous As-Fe solid phases. When the tailings were equilibrated with de-ionized water, the solution exhibited extremely acidic conditions (pH 2.01-3.10) and high concentrations of dissolved As (up to 29.5 mg L(-1)), indicating high potentials for As to be released during rainfall events. The downstream water was affected by drainage from tailings and contained 12.7-522 microg L(-1) of As. The amorphous As-Fe phases in tailings have not entirely been stabilized through the long term natural weathering processes. To remediate the environmental harms they had caused, anthropogenic interventions to stabilize or immobilize As in the tailings pile should be explored.

Arsenates↗

Chloride current observed as calcium-gated tail current in trigeminal root ganglion neurons of the marine catfish, Plotosus.

Isolated trigeminal ganglion (TRG) neurons of Plotosus in primary culture were studied with patch electrodes in a whole-cell recording configuration. When Ca currents were isolated using electrodes filled with CsCl and Ca buffer in Na- and K-free saline, a large tail current was induced. Both Ca and tail currents were blocked by 2 mM Co2+ in the bath. Reversal potential of the tail current was close to the equilibrium potential for Cl-. The reversal potential was altered by substitution of external Cl- with Br- or methanesulphonate- (MSA-). The anion permeability ratios were estimated as PBr/PCl = 1.95 and PMSA/PCl < 0.05. These results suggested that the tail current was the Ca-gated Cl current. In Plotosus neurons, two types of Ca current, high- and low-voltage activated (HVA and LVA), have been described. Both types of Ca currents were able to induce a tail current. Ba currents through both HVA and LVA channels proved to be ineffective. Upon repetitive activation, the tail current progressively increased in the presence of a nearly constant peak Ca current, and showed a more prolonged complex decay phase. When the electrode was filled with 20 mM EGTA, no tail current was induced, not even after repetitive stimulation. Therefore, the tail current seemed to be regulated by local Ca activity in the vicinity of the membrane. The Ca-gated Cl tail current may regulate the membrane excitability of TRG neurons during repetitive firing.

Animals↗

Fluid migration through the tail of the Dalkon shield intrauterine device.

X-ray radiographs were used to monitor the migration of Renouve -dip radiopaque tracer through the multifilament tail of Dalkon Shield intrauterine devices (IUDs). The movement of the tracer was more rapid and migrated a greater distance through the long end of the tail than through the short end of the tail. The double knot serves as at least a temporary barrier to the migration of tracer from the long end of the tail, but this barrier was circumvented when drops of Renouve -dip radiotracer were placed at both ends of the tail. Migration of Renouve -dip radiotracer was prevented when the end of the Dalkon Shield tail was fused by heating. No migration of this tracer occurred on the tails of commonly used IUDs which possessed monofilament tails, thus demonstrating that fluid migration occurs within and not on the surface of the multifilament tail.

Capillary Action↗

On the characteristics of the inward tail current induced by calcium overload.

The characterization of an inward tail current (Iex) induced by calcium overload and often associated with the oscillatory current (Ios) was studied by means of a two-microelectrode voltage clamp method in sheep cardiac Purkinje fibers. It was found that: (1) the inward tail current requires a prior depolarization to about -25 mV (or less negative values) in order to appear; (2) after depolarization to those values, the membrane needs to be repolarized to about -45 mV (or to more negative values) for the inward tail current to be initiated; (3) the inward tail current becomes larger after larger or longer clamp steps and increases progressively at more negative potentials; (4) the inward tail current can be separated from other known currents, notably from the pacemaker current; (5) the inward tail current is reduced by quinacrine, a blocker of Na-Ca exchange; (6) the inward tail current does not reverse at less negative potentials; (7) the membrane conductance does not increase during the inward tail current. Thus, the inward tail current shows similarities and dissimilarities with the oscillatory current, probably in relation to a common final pathway and to a different mode of onset of the two currents, respectively.

Animals↗

The human tail and spinal dysraphism.

Recent publications have endeavoured to differentiate between the true, or vestigial tail, and the pseudotail by clinical and pathological examination, and have indicated the benign nature of the true tail. The true tail arises from the most distal remnant of the embryonic tail, contains adipose, connective, muscle, and nerve tissue, and is covered by skin. Pseudotails represent a variety of lesions having in common a lumbosacral protrusion and a superficial resemblance to vestigial tails. A review of the case reports indicates spina bifida to be the most frequent coexisting anomaly with both. A review of occult spinal dysraphism shows it to be associated with cutaneous signs in more than 50% of instances. Three cases of spinal dysraphism with tail-like cutaneous structures are described and their radiological, operative, and pathological findings presented. The classification of each of the appendages into true tail or pseudotail remains obscure. Although the finding of these three tails was the subject of much curiosity, surgical treatment was clearly designed to adequately deal with the associated dysraphic state. The presence of a tail-like appendage in the lumbosacral region should alert the clinician to the possibility of underlying spinal dysraphism. Preoperative assessment must include a complete neurological history and examination as well as computed tomographic or magnetic resonance imaging.

Bone Neoplasms↗

Mechanisms behind tailing in the pressure inactivation curve of a clinical isolate of Escherichia coli O157:H7.

The tailing in pressure inactivation curve of clinically isolated Escherichia coli O157:H7 was investigated. A typical tailing was observed after the treatment period for 30min when 10(7) CFU/ml of the cell suspension was subjected to pressure treatment at 300MPa and 25 degrees Celsius. There was no effect on the tailing profiles by the addition of pressure-killed cells and released cellular components. When cells survived at a tail portion were re-propagated (tail-culture) and subjected to second pressure treatment, the cells of the tail-culture exhibited eminently higher barotolerance compared to those of the original-culture, suggesting that the presence of genetically pressure-resistant subpopulation was responsible for the tailing. The cytoplasmic membrane of the tail-culture cells had higher stability to a pressure treatment at 100MPa for 10min than that of the original-culture, which was evidenced by lower permeability to ethidium bromide. The addition of non-ionic surfactants including 0.5microl/ml polyoxyethylene p-t-octylphenyl ester (Triton X-100) and 0.53mg/ml lauric sugar ester dramatically reduced the level of tailing and made the inactivation curve linear.

Colony Count, Microbial↗

The N-terminal tails of the H2A-H2B histones affect dimer structure and stability.

The histone proteins of the core nucleosome are highly basic and form heterodimers in a "handshake motif." The N-terminal tails of the histones extend beyond the canonical histone fold of the hand-shake motif and are the sites of posttranslational modifications, including lysine acetylations and serine phosphorylations, which influence chromatin structure and activity as well as alter the charge state of the tails. However, it is not well understood if these modifications are signals for recruitment of other cellular factors or if the removal of net positive charge from the N-terminal tail plays a role in the overall structure of chromatin. To elucidate the effects of the N-terminal tails on the structure and stability of histones, the highly charged N-terminal tails were truncated from the H2A and H2B histones. Three mutant dimers were studied: DeltaN-H2A/WT H2B; WT H2A/DeltaN-H2B, and DeltaN-H2A/DeltaN-H2B. The CD spectra, stabilities to urea-denaturation, and the salt-dependent stabilization of the three truncated dimers were compared with those of the wild-type dimer. The data support four conclusions regarding the effects of the N-terminal tails of H2A and H2B: (1) Removal of the N-terminal tails of H2A and H2B enhance the helical structure of the mutant heterodimers. (2) Relative to the full-length WT heterodimer, the DeltaN-H2A/WT H2B dimer is destabilized, while the WT H2A/DeltaN-H2B and DeltaN-H2A/DeltaN-H2B dimers are slightly stabilized. (3) The truncated dimers exhibit decreased m values, relative to the WT dimer, supporting the hypothesis that the N-terminal tails in the isolated dimer adopt a collapsed structure. (4) Electrostatic repulsion in the N-terminal tails decreases the stability of the H2A-H2B dimer.

Animals↗

Protein anatomy: C-tail region of human tau protein as a crucial structural element in Alzheimer's paired helical filament formation in vitro.

Tau is a microtubule-associated protein in mammalian brain. In Alzheimer's disease, this protein is present in the somatodendritic compartment of certain nerve cells, where it forms a portion of paired helical filament, the major constituent of the neurofibrillary tangle. For clarification of the mechanism of this formation, recombinant human tau and its fragments (N-terminal half, C-terminal half, and 4-repeats) expressed in Escherichia coli were prepared, eight peptide fragments (C-tails 1-8) of the C-tail region were synthesized, and the conformation and capacity for aggregation essential for filamentous structure formation in vitro were examined. Recombinant full-length tau, the N-terminal half, 4-repeats, and the C-terminal half did not form filamentous structures in aqueous solution after standing at 20 degrees C. Peptides corresponding to the C-tail region of tau, C-tail 5, C-tail 7, and C-tail 8, produced the paired filament or single straight filament in acidic solution. The rate of filament formation by each peptide was followed by circular dichroism, which showed the C-tails to have predominantly random coil structures immediately following dissolution in aqueous solution and be gradually converted to the beta-sheet structure. The kinetics of aggregation were characterized by a delay period during which the solution remained clear, followed by a nucleation event which led to a growth phase, whose negative peak intensity at 218 nm in circular dichroism increased due to filamentous structure formation. This delay was eliminated by seeding supersaturated solution of preformed filaments. C-tails interacted with recombinant full-length tau to form definite single straight filament. The C-tail region of tau is thus shown indispensable to the formation of paired helical filament and nucleation to reduce the rate of paired helical filament formation in amyloidogenesis in vitro. These findings may provide some clarification of the pathogenesis of Alzheimer's disease.

Alzheimer Disease↗

Characteristics of iron ore tailing slime in India and its test for required pond size.

The physical and chemical nature of the tailing slime depends on milling operations and water content in the effluent. The characteristics of the tailings dictate the type of disposal facility required. Characteristics of the tailings, transportation from beneficiation plants and disposal system are described. Studies on tailing slime have been carried out at iron ore mines in Orissa and the results are discussed. The tailings contain toxic elements and find their way into the water environment. Sedimentation test was carried out on tailings and the area required for tailing pond was found to be 3155 m2 in comparison to 10000 m2 obtained from the use of an empirical equation. Provision of tailing pond for the disposal of tailings is a conservation of resources in addition to pollution control, and sedimentation test is essential for required pond size calculation.

India↗

Evidence for in vivo modulation of chloroplast RNA stability by 3'-UTR homopolymeric tails in Chlamydomonas reinhardtii.

Polyadenylation of synthetic RNAs stimulates rapid degradation in vitro by using either Chlamydomonas or spinach chloroplast extracts. Here, we used Chlamydomonas chloroplast transformation to test the effects of mRNA homopolymer tails in vivo, with either the endogenous atpB gene or a version of green fluorescent protein developed for chloroplast expression as reporters. Strains were created in which, after transcription of atpB or gfp, RNase P cleavage occurred upstream of an ectopic tRNA(Glu) moiety, thereby exposing A(28), U(25)A(3), [A+U](26), or A(3) tails. Analysis of these strains showed that, as expected, polyadenylated transcripts failed to accumulate, with RNA being undetectable either by filter hybridization or reverse transcriptase-PCR. In accordance, neither the ATPase beta-subunit nor green fluorescent protein could be detected. However, a U(25)A(3) tail also strongly reduced RNA accumulation relative to a control, whereas the [A+U] tail did not, which is suggestive of a degradation mechanism that does not specifically recognize poly(A), or that multiple mechanisms exist. With an A(3) tail, RNA levels decreased relative to a control with no added tail, but some RNA and protein accumulation was observed. We took advantage of the fact that the strain carrying a modified atpB gene producing an A(28) tail is an obligate heterotroph to obtain photoautotrophic revertants. Each revertant exhibited restored atpB mRNA accumulation and translation, and seemed to act by preventing poly(A) tail exposure. This suggests that the poly(A) tail is only recognized as an instability determinant when exposed at the 3' end of a message.

3' Untranslated Regions↗

The cytoplasmic tail of the human somatostatin receptor type 5 is crucial for interaction with adenylyl cyclase and in mediating desensitization and internalization.

We have investigated the role of the cytoplasmic tail (C-tail) of the human somatostatin receptor type 5 (hSSTR5) in regulating receptor coupling to adenylyl cyclase (AC) and in mediating agonist-dependent desensitization and internalization responses. Mutant receptors with progressive C-tail truncation (Delta347, Delta338, Delta328, Delta318), Cys320 --> Ala substitution (to block palmitoylation), or Tyr304 --> Ala substitution of a putative NPXXY internalization motif were stably expressed in Chinese hamster ovary K1 cells. Except for the Tyr304 --> Ala mutant, which showed no binding, all other mutant receptors exhibited binding characteristics (Kd and Bmax) and G protein coupling comparable with wild type (wt) hSSTR5. The C-tail truncation mutants displayed progressive reduction in coupling to AC, with the Delta318 mutant showing complete loss of effector coupling. Agonist pretreatment of wt hSSTR5 led to uncoupling of AC inhibition, whereas the desensitization response of the C-tail deletion mutants was variably impaired. Compared with internalization (66% at 60 min) of wt hSSTR5, truncation of the C-tail to 318, 328, and 338 residues reduced receptor internalization to 46, 46, and 23%, respectively, whereas truncation to 347 residues slightly improved internalization (72%). Mutation of Cys320 --> Ala induced a reduction in AC coupling, desensitization, and internalization. These studies show that the C-tail of hSSTR5 serves a multifunctional role in mediating effector coupling, desensitization, and internalization. Whereas coupling to AC is dependent on the length of the C-tail, desensitization and internalization require specific structural domains. Furthermore, internalization is regulated through both positive and negative molecular signals in the C-tail and can be dissociated from the signaling and acute desensitization responses of the receptor.

Adenylyl Cyclases↗

Phytostabilization of gold mine tailings, New Zealand. Part 1: Plant establishment in alkaline saline substrate.

Tailings from the Macraes mine, southern New Zealand, are prone to wind erosion. Use of a vegetation cover for physical stabilization is one potential solution to this environmental problem. This study used field trials contained in lysimeters to 1), test the ability of different plant species to grow in un/amended tailings and 2), provide background information on the nutrient and chemical content of waters in tailings. Barley (Hordeum vulgare), blue lupin (Lupinus angustifolius), and rye corn (Secale cereale) were trialed, using Superphosphate fertilizer and sewage sludge as amendments. Rye corn grew well in fertilizer-amended tailings, but poorly in unamended tailings; barley growth was similar in amended and unamended tailings; blue lupins grew poorly overall The tailings had alkaline pH (7-8.5) and water rapidly (< 1 mo) interacted with the tailings to become strongly saline. Minor acid generation was neutralized by calcite, with associated release of calcium and carbonate ions. Leachate waters were supersaturated with respect to calcite and dolomite. Dissolved sodium concentrations were up to 1000 mg L(-1), but elevated Ca2+ calcium and Mg2+ ensured that sodicity was lower than plant-toxic levels. Rye corn is a potentially useful plant for rapid phytostabilization of tailings, with only minor phosphate amendment required.

Biomass↗

Blood lead surveys of communities in proximity to lead-containing mill tailings.

In former mining communities tailings containing up to 2% (20,000 ppm) lead (Pb), frequently as galena (lead sulfide), may be present in large piles near residences, as landfill under homes, or mixed with residential soils. The impact of tailings on blood lead was assessed by comparing blood lead values obtained from residents and environmental lead measured in soils and tailings piles. Data from 13 communities were compiled. Approximately 2995 blood lead measurements were available from persons residing on or near tailings, with the majority of samples from children. Blood lead levels were compared to 1806 controls from nearby communities, national norms, and communities with active smelters. Data comparisons indicated that blood lead values in tailings residents were usually comparable to controls. These data suggest that lead present in mill tailings is not readily bioavailable, even to children who played in dirt or tailings piles. Consequently, the hazard of lead in soils appears to be site-specific and influenced by bioavailability; the bioavailability of galena tailings to humans is low. When health risks of lead soils are predicted, factors affecting the bioavailability of lead present in tailings need to be taken into account.

Biological Availability↗

Vertical distribution and mobility of arsenic and heavy metals in and around mine tailings of an abandoned mine.

In the present study, the vertical distributions (0-220 cm) of arsenic and heavy metals in mine tailings and nearby paddy fields, and their mobility through water-leach experiments were investigated. For the study, the area of Jingok mine located in Bongwha, Korea has been selected. The concentrations of arsenic and heavy metals in the mine tailings were extremely high compared to the paddy fields and control sites, i.e., up to 6675 mg/kg for As, 25 mg/kg for Cd, 22 mg/kg for Cr, 383 mg/kg for Cu, 11,135 mg/kg for Pb, 3600 mg/kg for Zn, 5.73 wt% for Fe, and 3.05 wt% for Mn. The concentrations of As and heavy metals in the paddy fields decreased sharply with increasing distance from the mine tailings, with values still higher than those in the control sites, indicating the contamination of the paddy fields by heavy metals released from the mine tailings. The vertical distributions of Cd, Cu, Pb, Al, Fe, and Mn showed the following common pattern: the highest values in the upper part of mine tailings (0-20 cm), rapid decrease with increasing depth, and then nearly constant values below the depth of 50 cm. Significant correlations were found between total Fe and heavy metals (Cd, Cu, and Pb), and between total Mn and heavy metals (Cd, Cu, Pb, and Zn) in the mine tailings, indicating that minerals containing Fe and Mn play an important role in the mobility of heavy metals such as Cd, Cu, Pb, and Zn. The fraction of As(V) ranged from 63 to 100% of total arsenic in the samples of the mine tailings. The high concentrations of total As, heavy metals, sulfate. hydrogen ion, and As(V) in the leachates of mine tailings suggest that sulfide minerals containing arsenic and heavy metals in the mine tailings were actively oxidized.

Agriculture↗

Efficacy of human islet isolation from the tail section of the pancreas for the possibility of living donor islet transplantation.

BACKGROUND: Islet transplantation is on the rise for the treatment of type 1 diabetes. Apparent donor shortages could be alleviated through use of living donor pancreata. A critical issue for using a section of pancreas from living donors is whether islet yields would be sufficient for transplantation. METHODS: After obtaining human pancreata, islets were isolated from the head section (n=20, head group), tail section (n=23, tail group) or whole pancreas (n=24, whole group). Islets were isolated by enzymatic digestion followed by purification, then assessed for yields, purity, morphology, functionality, and insulin content. RESULTS: Fifteen of twenty cases (75%) in the head group, all cases (100%) in the tail group, and 23 of 24 cases (96%) in the whole group were successfully completed for islet isolation. Islet yield per gram pancreas was significantly higher in the tail group compared with both the head and whole groups (head, 1,472+/-326 IE/g; tail, 4,256+/-574 IE/g; whole, 2,424+/-506 IE/g). Total islet yield from the head group was significantly lower compared with both tail and whole groups (head, 75,016+/-18,933 IE; tail, 197,469+/-28,236 IE; whole, 208,207+/-43,414 IE), and the tail group showed similar islet yield to the whole group. The whole group showed significantly lower purities and the head group showed significantly lower morphologic scores. There were no significant differences in viability, function, and insulin content among the three groups. CONCLUSIONS: The tail section of the human pancreas is suitable for islet isolation. The living donor islet transplantation may be feasible using only this section of the pancreas for the first transplantation to reduce hypoglycemic unawareness for small recipients, which might be followed by the second islet transplantation from cadaveric donor.

Adult↗