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At least 91 records · Page 5Linked to original sources

Deep learning-based annotation of plant abiotic stress resistance genes for crops.

The declining costs of DNA sequencing have expanded genomic data, crucial for understanding plant abiotic stress responses and crop improvement. However, accurate gene annotation remains challenging. To address this limitation, we propose the PASRGA, a deep learning approach that leverages transfer learning and contrastive learning to annotate genes related to drought, salt, cold, and UV resistance. PASRGA achieves high F1-scores, area under the receiver operating characteristic (AUROC), area under the precision-recall curve (AUPRC), and Matthews correlation coefficient (MCC) in annotating stress resistance genes, significantly outperforming the general protein annotation model CLEAN, the plant phosphatase gene annotation model PF-NET, the top-ranked model in the CAFA5 challenge NetGO 4.0, and four traditional machine learning methods. Its effectiveness was further validated with a salt stress treatment experiment in Eutrema salsugineum. To facilitate crop breeding practices, we utilized PASRGA to annotate the genomes of 17 major crops. To improve accessibility and utility, we incorporated both manually curated and PASRGA-predicted gene data, together with the PASRGA tool, into the PlantASRG database (https://bioinfor.nefu.edu.cn/PlantASRG/). This comprehensive resource aims to support crop breeding initiatives and ensure food security.

Crops, Agricultural↗

A present-day aminoacyl-tRNA synthetase with ancestral editing properties.

Leucyl-, isoleucyl-, and valyl-tRNA synthetases form a subgroup of related aminoacyl-tRNA synthetases that attach similar amino acids to their cognate tRNAs. To prevent amino acid misincorporation during translation, these enzymes also hydrolyze mischarged tRNAs through a post-transfer editing mechanism. Here we show that LeuRS from the deep-branching bacterium Aquifex aeolicus edits the complete set of aminoacylated tRNAs generated by the three enzymes: Ile-tRNA(Ile), Val-tRNA(Ile), Val-tRNA(Val), Thr-tRNA(Val), and Ile-tRNA(Leu). This unusual enlarged editing property was studied in a model of a primitive editing system containing a composite minihelix carrying the triple leucine, isoleucine, and valine identity mimicking the primitive tRNA precursor. We found that the freestanding LeuRS editing domain can edit this precursor in contrast to IleRS and ValRS editing domains. These results suggest that A. aeolicus LeuRS carries editing properties that seem more primitive than those of IleRS and ValRS. They suggest that the A. aeolicus editing domain has preserved the ambiguous editing property from the ancestral common editing domain or, alternatively, that this plasticity results from a specific metabolic adaptation.

Bacteria↗

Extended, strategic therapy for recalcitrant mind/body healing: an integrative model.

The development of the power therapies, behavioral medicine, and short term interventions have reported such success even with trauma cases that it is relevant to question the justification for lengthy psychotherapy. Yet some patients with complex mind/body conditions impervious to medical treatment/hypnosis may require extended, multi-modal, integrative therapy. This paper details a single complex case of paruresis as a prototype for illustrating a holographic treatment model for recalcitrant conditions: Component features of the proposed model presented include: 1) the sequential utilization of hypnobehavioral and analytic approaches; 2) uncovering work providing access to the somatic ego state associated with the illness condition; 3) the extended treatment time frame required for deep psycho-physiological change; and 4) the stages of counter-transference expectably evoked by such patients (e.g. urgency, exuberant optimism, frustration, discouragement), and the transformation of such reactions to achieve maximum therapeutic efficacy.

Adult↗

Does the effect of familiarity on proofreading change with encoding task and time?

The authors examined whether the beneficial effect of text familiarity on proofreading is dependent on the type of encoding operations performed on the text prior to proofreading (i.e., surface vs. deep), and on the time elapsed between encoding and proofreading. In the present study, familiarity, irrespective of the nature of the encoding operations and delay, improved proofreading times, whereas only surface encoding made proofreading more accurate. These results represent a challenge for the transfer-appropriate processing model of memory.

Attention↗

Mode of insertion of the signal sequence of a bacterial precursor protein into phospholipid bilayers as revealed by cysteine-based site-directed spectroscopy.

The interactions between a bacterial precursor protein and phospholipids in bilayer-based model membrane systems is addressed in this study. The precursor-lipid interactions were assessed from the side of the lipid phase by fluorescence and electron spin resonance spectroscopy, using the precursor of the Escherichia coli outer membrane protein PhoE. The role of the signal sequence, as part of the precursor, in this interaction was investigated by using cysteine-based site-directed spectroscopy. For this purpose, purified cysteine-containing mutants of prePhoE, which were made by site-directed mutagenesis of the signal sequence part and of the mature part, and defined lipids were used. The location of the fluorescently labeled cysteine residues was established by resonance energy transfer and quenching experiments and those of the corresponding spin-labeled cysteine residues by paramagnetic relaxation enhancement. It was demonstrated that precursor-phospholipid interactions exist in model membrane systems and also that these interactions were dependent on the presence of anionic phospholipids and resulted in a deep insertion of (parts of) the precursor into the lipid bilayer. Furthermore, the results with the cysteine mutations in the signal sequence of the precursor indicate that both termini of the signal sequence are located near or at the membrane surface, with only the fluorescence of the labeled cysteines in the signal sequence part being protected against aqueous quenchers. The results demonstrate that, when part of the intact precursor, the signal sequence experiences similar lipid-protein interactions as do isolated signal peptides. They also indicate that the signal sequence inserts entirely as a looped structure into the membrane. In addition, the data also indicate that the mature part of the precursor has an affinity for the membrane.

Amino Acid Sequence↗

A supermicrosurgical flap model in the rat: a free true abdominal perforator flap with a short pedicle.

BACKGROUND: Perforator flaps have recently gained considerable popularity in reconstructive surgery, and their importance and advantages over conventional flaps have been widely accepted. Given the improvements in microsurgical techniques, researchers have encouraged the search for further perforator flap sources, such as a perforator flap with a short pedicle only. The purpose of this study was to describe a true perforator flap model with a short vascular pedicle in the abdominal region in the rat. METHODS: Twenty-six adult Sprague-Dawley rats weighing 400 to 500 g were used. In 10 rats, the perforator vascular anatomy of the abdominal region was determined by anatomic dissection. In the remaining 16 rats, a true abdominal perforator-based flap was created based on a short segment of deep epigastric vessels. In eight rats, the flap was transferred to the groin region as a free flap, and anastomosis was performed between the artery and vein of the flap and the superficial inferior epigastric artery and vein of the recipient site. In addition, in two of these flaps, the long thoracic vein of the flap was anastomosed to the femoral vein. In the remaining eight rats, the flap was transferred to the groin region, but in this group anastomosis was not performed. The latter group was designated as the control group. RESULTS: The skin islands of seven free perforator flaps survived completely, and the one remaining flap was determined to be necrotic. All the flaps in the control group underwent complete necrosis. CONCLUSIONS: Not only is the free abdominal perforator flap a reliable and true perforator flap model for future physiological, biological, and pharmacological studies, it is also an excellent self-controlled supermicrosurgical training model for learning proper techniques, meticulous intramuscular dissection of true perforator flaps, and anastomosis of small-caliber vessels.

Anastomosis, Surgical↗

Formation of Millisecond Pulsars with Heavy White Dwarf Companions: Extreme Mass Transfer on Subthermal Timescales.

We have performed detailed numerical calculations of the nonconservative evolution of close X-ray binary systems with intermediate-mass (2.0-6.0 M middle dot in circle) donor stars and a 1.3 M middle dot in circle accreting neutron star. We calculated the thermal response of the donor star to mass loss in order to determine its stability and follow the evolution of the mass transfer. Under the assumption of the "isotropic reemission model," we demonstrate that in many cases it is possible for the binary to prevent a spiral-in and survive a highly super-Eddington mass transfer phase (1<<M&d2;&solm0;M&d2;Edd<105) on a subthermal timescale if the convective envelope of the donor star is not too deep. These systems thus provide a new formation channel for binary millisecond pulsars with heavy CO white dwarfs and relatively short orbital periods (3-50 days). However, we conclude that to produce a binary pulsar with a O-Ne-Mg white dwarf or Porb approximately 1 day (e.g., PSR B0655+64) the above scenario does not work, and a spiral-in phase is still considered the most plausible scenario for the formation of such a system.

Journal Article↗

Molecular modeling of protocellular functions.

The mechanisms of three protocellular functions have been studied using molecular modeling techniques. These functions are (1) the transport of ions across membranes, (2) the formation of photoactivated proton gradient that could drive chemical synthesis in the protocell, and (3) the organization of small peptides necessary for catalytic activity. In all these processes, membranes play an essential role. The transfer of ions across the barrier formed by protocellular walls is facilitated by the formation of deep, thinning defects in the membrane. Membranes also form a barrier to charged species that allows for retaining proton gradients. These gradients can be generated by a simple transmembrane proton pump consisting of a proton source and two acceptors. The directionality of the pump is ensured by a "gate-keeping" mechanism involving a water molecule, conformational change of the primary acceptor or tautomerization of a histidine. The pump can be formed by two transmembrane helices but not one helix. They provide surfaces at which organic molecules concentrate and small peptides can organize into ordered, amphiphilic structures. In general, valuable information about the origins and evolution of protocells can be obtained from the knowledge of physical and chemical principles that govern functioning of contemporary cells.

Amino Acid Sequence↗

Development of a new mini-invasive tumour hyperthermia probe using high-temperature water vapour.

A new mini-invasive hyperthermia probe using high-temperature water vapour for deep regional tumour treatment was developed in this paper. The vacuum insulation mechanism was incorporated into the probe to avoid heating damage to the normal tissues around the edge of the insertion path. To better understand the heat transfer behaviour in living tissues due to operation of the probe, theoretical models based on the Pennes' equation were established and two closed form analytical solutions under constant flux or temperature heating at the tip of probe were obtained. Parametric studies were performed to investigate the influence of various parameters on the temperature response of tissues heated by the probe. Further, several simulating experiments on the actual heating performance of the probe fabricated in this paper were conducted on the in vitro biological materials (fresh pork) and phantom gel. It was demonstrated that the probe can cause a high enough temperature over the treatment area to thermally destroy the tumour tissue in due time, while the temperature over the surrounding healthy tissues can be kept below a safe threshold value. This mini-invasive heating probe may have significant applications in future clinical tumour hyperthermia.

Animals↗

Theory and experiment for the effect of vascular microstructure on surface tissue heat transfer--Part I: Anatomical foundation and model conceptualization.

A new theoretical model supported by ultrastructural studies and high-spatial resolution temperature measurements is presented for surface tissue heat transfer in a two-part study. In this first paper, vascular casts of the rabbit thigh prepared by the tissue clearance method were serially sectioned parallel to the skin surface to determine the detailed variation of the vascular geometry as a function of tissue depth. Simple quantitative models of the basic vascular structures observed were then analyzed in terms of their characteristic thermal relaxation lengths and a new three-layer conceptual model proposed for surface tissue heat transfer. Fine wire temperature measurements with an 80-micron average diameter thermocouple junction and spatial increments of 20 micrometers between measurement sites have shown for the first time the detailed temperature fluctuations in the microvasculature and have confirmed the fundamental assumptions of the proposed three-layer model for the deep tissue, skeletal muscle and cutaneous layers.

Animals↗

Augmented, pulsating tactile feedback facilitates simulator training of clinical breast examinations.

Haptic training devices can facilitate tactile skill development by providing repeatable exposures to rare stimuli. Extant haptic training simulator research primarily emphasizes realistic stimuli representation; however, the experiments reported herein suggest that providing augmented feedback can improve training effectiveness, even when the feedback is not natural. A novel clinical breast examination training device uses inflated balloons embedded in silicone to simulate breast lumps. Oscillating the balloon water pressure makes the lumps pulsate. The pulsating lumps are easier to detect than the static lumps used in current simulators, and this manipulation seems to effectively introduce trainees to small, deep lumps that are initially difficult to perceive. A study of 48 medical students indicates that training with the dynamic breast model increased the number of lumps detected, F(1, 47) = 9.34, p = .004, decreased the number of false positives, F(1, 47) = 5.78, p = .020, and improved intersimulator skill transfer, F(1, 47) = 26.56, p < .001. The results suggest that at least in this case, augmented, tactile feedback increases training effectiveness, despite the fact that the feedback does not attempt to mimic any physical phenomenon present in the natural stimulus. Applications of this research include training techniques and tools for improved detection of palpable cancers.

Adult↗

Magnetic resonance imaging with implanted neurostimulators: numerical calculation of the induced heating.

Magnetic resonance imaging (MRI) is still contraindicated in patients with implanted active medical devices, as the applied radiofrequency (RF) fields can lead to significant heating of the implants and the electrodes. A head model with an implanted deep brain stimulation electrode (DBS) was exposed to a continuous RF-field similar to the excitational field used in MRI at a frequency of 64 MHz. In this study a two-step procedure for the accurate estimation of electrode-heating during MRI is presented. First the energy loss was calculated in the frequency domain during an applied RF-pulse. Then a thermodynamic algorithm taking heat transfer mechanisms into account was used. The applied method showed to be numerically stable and gave more accurate results than first calculated using a simple worst-case approximation.

Algorithms↗

Transplantation of adenovirally transduced allogeneic chondrocytes into articular cartilage defects in vivo.

Gene transfer to chondrocytes followed by intra-articular transplantation may allow for functional modulation of chondrocyte biology and enhanced repair of damaged articular cartilage. We chose to examine the loss of chondrocytes transduced with a recombinant adenovirus containing the gene for Escherichia coli beta-galactosidase (Ad.RSVntlacZ), followed by transplantation into deep and shallow articular cartilage defects using New Zealand White rabbits as an animal model. A type I collagen matrix was used as a carrier for the growth of the transduced chondrocytes and to retain the cells within the surgically created articular defects. Histochemical analysis of matrices recovered from the animals 1, 3 and 10 days after implantation showed the continued loss of lacZ positive chondrocytes. The number of cells recovered from the matrices was also compared with the initial innoculum of transduced cells present within the matrices at the time of implantation. The greatest loss of transduced cells was observed in the first 24 h after implantation. The numbers of transduced cells present within the matrices were relatively constant between 1 and 3 days postimplantation, but had progressively declined by 10 days postimplantation. These results suggest that transduction of chondrocytes followed by intra-articular transplantation in this rabbit model may enable us to examine the biological effects of focal transgenic overexpression of proteins involved in cartilage homeostasis and repair.

Adenoviridae↗

Central mechanisms of visceral pain.

Deep pain arising from muscle, joints, connective tissue, and the viscera is different in character and quality from pain arising from cutaneous structures. Deep pains, particularly visceral pain, are poorly localized, typically referred or transferred to a cutaneous site, and generally produce strong emotional and autonomic responses and tonic muscle contractions. Despite the prevalence and clinical importance of deep pains, it is only relatively recently that investigative efforts have begun to focus on the mechanisms of deep pain. The present report briefly reviews the development and use of a model of visceral pain that employs constant pressure distension of the colon and rectum as a noxious stimulus. Converging behavioral, pharmacological, and physiological evidence that colorectal distension is a valid, reliable, noxious, visceral stimulus is presented.

Animals↗

Diffusion and perfusion limitation in alveolar O2 exchange: shape of the blood O2 equilibrium curve.

The limitations imposed by diffusion (Ldiff) and perfusion (Lperf) on alveolar gas exchange can be estimated using a simple model of alveolar-capillary gas transfer (Piiper and Scheid (1981) Respir, Physiol. 46: 193-208). These limitations indicate the fractional increase of gas exchange that would occur by raising pulmonary conductances for diffusion or perfusion to functionally infinite values. The (simple) model assumes linear relations between concentration and partial pressure for the gases studied. We have investigated in this study the effects of this assumption for estimating Ldiff and Lperf for O2 whose blood equilibrium curve is particularly non-linear in normoxia. The calculations suggest that Lperf is only slightly overestimated by the assumption of linear blood O2 binding. For Ldiff, there is a significant overestimation in normoxia, but in hypoxia the linear equilibrium curve yields sufficiently accurate estimates. Calculations for data estimated for man on the summit of Mt. Everest suggest that alveolar O2 uptake in deep hypoxia at rest is mainly limited by perfusion and to a lesser degree by diffusion (Lperf greater than Ldiff). For the sustained exercise of climbing, on the other hand, diffusion limitation is more prominent than perfusion limitation (Ldiff greater than Lperf). Large values of Ldiff are estimated for normoxic O2 uptake across the skin of the gill-less and lung-less salamander, and here, the effects of the alinearity of the O2 equilibrium curve are pronounced. It is concluded that the simplified model of alveolar-capillary gas transfer, with linear O2 equilibrium curve, can be very useful to estimate diffusion and perfusion limitations from experimental data.

Altitude↗

A free flap system in sheep.

Five successful free flap transfers have been performed using the deep circumflex iliac artery system in sheep. The system is capable of providing cutaneous, myocutaneous, or osteomyocutaneous flaps, and details regarding these flaps are described.

Animals↗

Minimization of polypeptide energy. 8. Application of the deflation technique to a dipeptide.

In minimizing the energy of a polypeptide, it is necessary to be able to move out of local minima in the search for the global minimum of the energy. For this purpose, the standard technique of deflation (in solving systems of nonlinear equations) is described and applied to the calculation of various stationary points on the energy surface of the "dipeptide" glycyl-L-alanine. The results compare favorably with a detailed contour map of the energy surface. Of special interest is a deep minimum near (varphi,Psi) approximately (240 degrees , 120 degrees ) which was found by the deflation technique but which had usually been overlooked in previous investigations.

Energy Transfer↗

Locomotion on the water surface: propulsive mechanisms of the fisher spider

Using kinematic and mechanical experiments, we have shown how fisher spiders, Dolomedes triton (Araneae, Pisauridae), can generate horizontal propulsive forces using their legs. This horizontal thrust is provided primarily by the drag of the leg and its associated dimple as both move across the water surface. Less important sources of resistance are surface tension and bow waves. The relative contributions of drag, surface tension and bow waves were examined in several different ways. In one experiment, we measured the forces acting on a leg segment as water flowed past it in non-turbulent flow; the bow wave was not present at leg relative velocities below 0.2ms-1 and thus cannot play a role in thrust production at low leg speeds. In a second experiment, we varied the surface tension by altering the concentration of ethanol from 0% to 9% in the experimental water tank. At a constant dimple depth, force varied little with changes in surface tension, a result consistent with the hypothesis that drag is the primary source of resistance. In addition, however, as surface tension decreased from 0.072 to 0.064Nm-1, the power exponent of the relationship between force and velocity (as measured by the exponent of the power function relating the two variables) increased; at lower surface tensions, down to 0.054Nm-1, the power exponent of the relationship between force and velocity decreased. These results suggest an influence of surface tension (albeit still secondary to drag) in generating horizontal resistance to leg movement. We also measured flow disturbance in the water downstream from a leg segment and confirmed that, even at velocities well below 0.2ms-1, the leg-cum-dimple transferred momentum to the water, which is a clear indication that drag is a contributor to the resistance encountered by a spider's leg. Finally, modeling the leg-cum-dimple as a circular cylinder generates values of drag that account for 75&shy;98% of the measured leg force when the dimple is 0 or 1mm deep. These results not only elucidate the primary mechanism of propulsion for D. triton and other similar-sized arthropods, such as adult water striders (Gerridae), but also suggest that the formerly enigmatic locomotion of very small water-walking organisms (e.g. first-instar water striders) can be understood in the same way.

Journal Article↗