bluuebunny/crossref_metadata_2025 huggingface dataset:
Targeting the metabolic vulnerability of acute myeloid leukemia blasts with a combination of venetoclax and 8-chloro-adenosine
Authors: Buettner Ralf , Nguyen Le Xuan Truong , Morales Corey , Chen Min-Hsuan , Wu Xiwei , Chen Lisa S. , Hoang Dinh Hoa , Hernandez Vargas Servando , Pullarkat Vinod , Gandhi Varsha , Marcucci Guido , Rosen Steven T.
Published: April 2021

Background

BCL‐2 inhibition through venetoclax (VEN) targets acute myeloid leukemia (AML) blast cells and leukemic stem cells (LSCs). Although VEN-containing regimens yield 60–70% clinical response rates, the vast majority of patients inevitably suffer disease relapse, likely because of the persistence of drug-resistant LSCs. We previously reported preclinical activity of the ribonucleoside analog 8-chloro-adenosine (8-Cl-Ado) against AML blast cells and LSCs. Moreover, our ongoing phase I clinical trial of 8-Cl-Ado in patients with refractory/relapsed AML demonstrates encouraging clinical benefit. Of note, LSCs uniquely depend on amino acid-driven and/or fatty acid oxidation (FAO)-driven oxidative phosphorylation (OXPHOS) for survival. VEN inhibits OXPHOS in LSCs, which eventually may escape the antileukemic activity of this drug. FAO is activated in LSCs isolated from patients with relapsed AML.

Methods

Using AML cell lines and LSC-enriched blast cells from pre-treatment AML patients, we evaluated the effects of 8-Cl-Ado, VEN and the 8-Cl-Ado/VEN combination on fatty acid metabolism, glycolysis and OXPHOS using liquid scintillation counting, a Seahorse XF Analyzer and gene set enrichment analysis (GSEA). Western blotting was used to validate results from GSEA. HPLC was used to measure intracellular accumulation of 8-Cl-ATP, the cytotoxic metabolite of 8-Cl-Ado. To quantify drug synergy, we created combination index plots using CompuSyn software. The log-rank Kaplan–Meier survival test was used to compare the survival distributions of the different treatment groups in a xenograft mouse model of AML.

Results

We here report that VEN and 8-Cl-Ado synergistically inhibited in vitro growth of AML cells. Furthermore, immunodeficient mice engrafted with MV4-11-Luc AML cells and treated with the combination of VEN plus 8-Cl-Ado had a significantly longer survival than mice treated with either drugs alone (p ≤ 0.006). We show here that 8-Cl-Ado in the LSC-enriched population suppressed FAO by downregulating gene expression of proteins involved in this pathway and significantly inhibited the oxygen consumption rate (OCR), an indicator of OXPHOS. By combining 8-Cl-Ado with VEN, we observed complete inhibition of OCR, suggesting this drug combination cooperates in targeting OXPHOS and the metabolic homeostasis of AML cells.

Conclusion

Taken together, the results suggest that 8-Cl-Ado enhances the antileukemic activity of VEN and that this combination represents a promising therapeutic regimen for treatment of AML.
Online questionnaire, clinical and biomechanical measurements for outcome prediction of plantar heel pain: feasibility for a cohort study
Authors: Gulle Halime , Prior Trevor , Miller Stuart , Birn‐Jeffery Aleksandra V. , Morrissey Dylan
Published: April 2021

Background

Plantar heel pain (PHP) accounts for 11–15% of foot symptoms requiring professional care in adults. Recovery is variable, with no robust prognostic guides for sufferers, clinicians or researchers. Therefore, we aimed to determine the validity, reliability and feasibility of questionnaire, clinical and biomechanical measures selected to generate a prognostic model in a subsequent cohort study.

Methods

Thirty‐six people (19 females & 17 males; 20–63 years) were recruited with equal numbers in each of three groups: people with PHP (PwPHP), other foot pain (PwOP) and healthy (H) controls. Eighteen people performed a questionnaire battery twice in a randomised order to determine online and face‐to‐face agreement. The remaining 18 completed the online questionnaire once, plus clinical measurements including strength and range of motion, mid‐foot mobility, palpation and ultrasound assessment of plantar fascia. Nine of the same people underwent biomechanical assessment in the form of a graded loaded challenge augmenting walking with added external weight and amended step length on two occasions. Outcome measures were (1) feasibility of the data collection procedure, measurement time and other feedback; (2) establishing equivalence to usual procedures for the questionnaire battery; known‐group validity for clinical and imaging measures; and initial validation and reliability of biomechanical measures.

Results

There were no systematic differences between online and face‐to‐face administration of questionnaires (p‐values all > .05) nor an administration order effect (d = − 0.31–0.25). Questionnaire reliability was good or excellent (ICC2,1_absolute)(ICC 0.86–0.99), except for two subscales. Full completion of the survey took 29 ± 14 min. Clinically, PwPHP had significantly less ankle‐dorsiflexion and hip internal‐rotation compared to healthy controls [mean (±SD) for PwPHP‐PwOP‐H = 14°(±6)‐18°(±8)‐28°(±10); 43°(±4)‐ 45°(±9)‐57°(±12) respectively; p < .02 for both]. Plantar fascia thickness was significantly higher in PwPHP (3.6(0.4) mm vs 2.9(0.4) mm, p = .01) than the other groups. The graded loading challenge demonstrated progressively increasing ground reaction forces.

Conclusion

Online questionnaire administration was valid therefore facilitating large cohort recruitment and being relevant to remote service evaluation and research. The physical and ultrasound examination revealed the expected differences between groups, while the graded loaded challenge progressively increases load and warrants future research. Clinician and researchers can be confident about these methodological approaches and the cohort study, from which useful clinical tools should result, is feasible.

Level of evidence

IV
The characteristics of insoluble softwood substrates affect fungal morphology, secretome composition, and hydrolytic efficiency of enzymes produced by Trichoderma reesei
Authors: Novy Vera , Nielsen Fredrik , Cullen Daniel , Sabat Grzegorz , Houtman Carl J. , Hunt Christopher G.
Published: April 2021

Background

On-site enzyme production using Trichoderma reesei can improve yields and lower the overall cost of lignocellulose saccharification by exploiting the fungal gene regulatory mechanism that enables it to continuously adapt enzyme secretion to the substrate used for cultivation. To harness this, the interrelation between substrate characteristics and fungal response must be understood. However, fungal morphology or gene expression studies often lack structural and chemical substrate characterization. Here, T. reesei QM6a was cultivated on three softwood substrates: northern bleached softwood Kraft pulp (NBSK) and lodgepole pine pretreated either by dilute-acid-catalyzed steam pretreatment (LP-STEX) or mild alkaline oxidation (LP-ALKOX). With different pretreatments of similar starting materials, we presented the fungus with systematically modified substrates. This allowed the elucidation of substrate-induced changes in the fungal response and the testing of the secreted enzymes’ hydrolytic strength towards the same substrates.

Results

Enzyme activity time courses correlated with hemicellulose content and cellulose accessibility. Specifically, increased amounts of side-chain-cleaving hemicellulolytic enzymes in the protein produced on the complex substrates (LP-STEX; LP-ALKOX) was observed by secretome analysis. Confocal laser scanning micrographs showed that fungal micromorphology responded to changes in cellulose accessibility and initial culture viscosity. The latter was caused by surface charge and fiber dimensions, and likely restricted mass transfer, resulting in morphologies of fungi in stress. Supplementing a basic cellulolytic enzyme mixture with concentrated T. reesei supernatant improved saccharification efficiencies of the three substrates, where cellulose, xylan, and mannan conversion was increased by up to 27, 45, and 2800%, respectively. The improvement was most pronounced for proteins produced on LP-STEX and LP-ALKOX on those same substrates, and in the best case, efficiencies reached those of a state-of-the-art commercial enzyme preparation.

Conclusion

Cultivation of T. reesei on LP-STEX and LP-ALKOX produced a protein mixture that increased the hydrolytic strength of a basic cellulase mixture to state-of-the-art performance on softwood substrates. This suggests that the fungal adaptation mechanism can be exploited to achieve enhanced performance in enzymatic hydrolysis without a priori knowledge of specific substrate requirements.
Unilateral and bilateral training competitive archers differ in some potentially unhealthy neck-shoulder region movement behaviour characteristics
Authors: Schmitt Mareike , Vogt Lutz , Wilke Jan , Niederer Daniel
Published: April 2021

Background

Excessive unilateral joint loads may lead to overuse disorders. Bilateral training in archery is only performed as a supportive coordination training and as a variation of typical exercise. However, a series of studies demonstrated a crossover transfer of training-induced motor skills to the contralateral side, especially in case of mainly unilateral skills. We compared the cervical spine and shoulder kinematics of unilateral and bilateral training archers.

Methods

In this cross-sectional study, 25 (5 females, 48 ± 14 years) bilaterally training and 50 age-, sex- and level-matched (1:2; 47.3 ± 13.9 years) unilaterally training competitive archers were included. Cervical range of motion (RoM, all planes) and glenohumeral rotation were assessed with an ultrasound-based 3D motion analysis system. Upward rotation of the scapula during abduction and elevation of the arm were measured by means of a digital inclinometer and active shoulder mobility by means of an electronic caliper. All outcomes were compared between groups (unilaterally vs. bilaterally) and sides (pull-hand- vs. bow-hand-side).

Results

Unilateral and bilateral archers showed no between group and no side-to-side-differences in either of the movement direction of the cervical spine. The unilateral archers had higher pull-arm-side total glenohumeral rotation than the bilateral archers (mean, 95% CI), (148°, 144–152° vs. 140°, 135°-145°). In particular, internal rotation (61°, 58–65° vs. 56°, 51–61°) and more upward rotation of the scapula at 45 degrees (12°, 11–14° vs. 8°, 6–10°), 90 degrees (34°, 31–36° vs. 28°, 24–32°), 135 degrees (56°, 53–59° vs. 49°, 46–53°), and maximal (68°, 65–70° vs. 62°, 59–65°) arm abduction differed. The bow- and pull-arm of the unilateral, but not of the bilateral archers, differed in the active mobility of the shoulder (22 cm, 20–24 cm vs. 18 cm, 16–20 cm).

Conclusions

Unilaterally training archers display no unphysiologic movement behaviour of the cervical spine, but show distinct shoulder asymmetris in the bow- and pull-arm-side when compared to bilateral archers in glenohumeral rotation, scapula rotation during arm abduction, and active mobility of the shoulder. These asymmetries in may exceed physiological performance-enhancing degrees. Bilateral training may seems appropriate in archery to prevent asymmetries.
PCJ Java library as a solution to integrate HPC, Big Data and Artificial Intelligence workloads
Authors: Nowicki Marek , Górski Łukasz , Bała Piotr
Published: April 2021

With the development of peta- and exascale size computational systems there is growing interest in running Big Data and Artificial Intelligence (AI) applications on them. Big Data and AI applications are implemented in Java, Scala, Python and other languages that are not widely used in High-Performance Computing (HPC) which is still dominated by C and Fortran. Moreover, they are based on dedicated environments such as Hadoop or Spark which are difficult to integrate with the traditional HPC management systems. We have developed the Parallel Computing in Java (PCJ) library, a tool for scalable high-performance computing and Big Data processing in Java. In this paper, we present the basic functionality of the PCJ library with examples of highly scalable applications running on the large resources. The performance results are presented for different classes of applications including traditional computational intensive (HPC) workloads (e.g. stencil), as well as communication-intensive algorithms such as Fast Fourier Transform (FFT). We present implementation details and performance results for Big Data type processing running on petascale size systems. The examples of large scale AI workloads parallelized using PCJ are presented.
A vacuum-driven rubber-band gripper
Authors: Yamada Ko , Mitsuda Takashi
Published: April 2021

Robotic grippers that gently handle objects of various shapes are required for various applications these days. Conventional finger-shaped grippers are multifunctional and can grip various objects; however, grasping an item without slippage requires planning the positioning of the fingers at appropriate locations on the item. Hence, a ring-shaped soft gripper that coils itself around objects like a rubber band is suggested in this paper. The proposed gripper comprises a soft tube containing laminated sponges interleaved with plastic sheets. Evacuation of the air within the sponges shrinks them and decreases the diameter of the ring, thereby allowing the gripper to firmly hold objects. The gripper is therefore flexible enough to coil around objects of various shapes without gaps. Furthermore, the rigidity of the compressed sponges inside the gripper prevents wobbling of the gripped objects. The air within the gripper can be used to adjust the gripping force. The minimum diameter of the gripper after evacuating the air within the sponges is approximately one-fourth of the original diameter. Thus, the proposed gripper is expected to be used in various applications as it automatically conforms to the different shapes while simply gripping objects gently and securely.
Qualitative study: burden of menopause-associated vasomotor symptoms (VMS) and validation of PROMIS Sleep Disturbance and Sleep-Related Impairment measures for assessment of VMS impact on sleep
Authors: English Marci , Stoykova Boyka , Slota Christina , Doward Lynda , Siddiqui Emad , Crawford Rebecca , DiBenedetti Dana
Published: April 2021

Purpose

We evaluated the impact of menopause-associated vasomotor symptoms (VMS) on sleep. We also sought to establish the content validity of Patient-Reported Outcomes Measurement Information System (PROMIS) short form Sleep-Related Impairment and Sleep Disturbance measures in postmenopausal women with moderate to severe VMS.

Methods

Cross-sectional, in-person, qualitative interviews were conducted in the United States (Texas, Illinois) and European Union (UK, France) with women aged 40–64 years experiencing moderate to severe VMS (≥35/wk). Main outcomes were impact of VMS on sleep based on concept elicitation and content validity of PROMIS Sleep-Related Impairment and Sleep Disturbance short forms via cognitive debriefing.

Results

Thirty-two women (US: n = 16; EU: n = 16) participated. A majority (US: 93.8%; EU: 93.8%) said VMS affected sleep; specifically, they had sleep interrupted by sweating or overheating and had difficulty returning to sleep. Sleep disturbance was the most bothersome aspect of VMS (US: 75%; EU: 50%). VMS-associated sleep disturbance affected next-day work productivity, mood, relationships, daily activities, concentration, social activities, and physical health. Participants found both PROMIS sleep measures relevant and easy to answer; the Sleep Disturbance measure was considered the most relevant. Participants had no difficulty remembering their experiences over the 7-day recall period and found the response options to be distinct.

Conclusion

VMS associated with menopause significantly interferes with sleep and next-day functioning (e.g., work productivity), supporting assessment of sleep outcomes in studies evaluating treatment of VMS. Women with moderate to severe VMS found that the PROMIS Sleep-Related Impairment and Sleep Disturbance short forms assessed constructs important to understanding sleep in the context of menopause-associated VMS.
Using dried kitchen food wastes as untraditional feed in growing rabbit's diets
Authors: Helal Farouk Imam Saad , El Badawi Alaa Eldin Yehia , Basyony Mohamed Mohamed , El Sabaawy Eman , El Naggar Soad
Published: April 2021

Background

Kitchen food wastes (KFW) are food lost from human especially from hotels, hospitals, cafeterias and home, could be alternative feed resources and create the attention of researchers to process these wastes and recycling it as animal feeding not only to reduce the use of expensive feed ingredients but also to decrease the environmental pollution. The main objective of this study was conducted to investigate the effect of dietary KFW inclusion on growth performance, digestibility, carcass traits, and some blood biochemical parameters of growing New Zealand White rabbits.

Results

The results showed that rabbits fed on diets containing 30% KFW achieved significantly (P < 0.05) higher daily weight gain (22.61 g) than the control (20.79 g) and there were no difference between diets 10% and 20%, and the lowest daily gain was with diet 40%. The highest organic matter (OM) and crude protein (CP) digestibility were recorded in rabbits fed on a diet containing 30% KFW (64.08 and 64.29%, respectively), while the lowest was observed in 40% group (61.11 and 55.54%, respectively). Diets containing KFW decreased caecal ammonia nitrogen (NH3–N) and increased propionate up to 30% substitution. The addition of KFW to rabbits diets had no significant effect (P < 0.05) on serum globulin, glucose, ALT, and AST values and increased significantly (P < 0.05) serum total protein, albumin, triglycerides, cholesterol and creatinine.

Conclusion

It can be concluded that the best growth performance and economical feed efficiency was observed in rabbits fed on a diet containing 30% KFW and surpassing all treated groups and achieved the best body weight gain.
Drug target ranking for glioblastoma multiforme
Authors: Saraf Radhika , Agah Shaghayegh , Datta Aniruddha , Jiang Xiaoqian
Published: April 2021

Background

Glioblastoma Multiforme, an aggressive primary brain tumor, has a poor prognosis and no effective standard of care treatments. Most patients undergoing radiotherapy, along with Temozolomide chemotherapy, develop resistance to the drug, and recurrence of the tumor is a common issue after the treatment. We propose to model the pathways active in Glioblastoma using Boolean network techniques. The network captures the genetic interactions and possible mutations that are involved in the development of the brain tumor. The model is used to predict the theoretical efficacies of drugs for the treatment of cancer.

Results

We use the Boolean network to rank the critical intervention points in the pathway to predict an effective therapeutic strategy for Glioblastoma. Drug repurposing helps to identify non-cancer drugs that could be effective in cancer treatment. We predict the effectiveness of drug combinations of anti-cancer and non-cancer drugs for Glioblastoma.

Conclusions

Given the genetic profile of a GBM tumor, the Boolean model can predict the most effective targets for treatment. We also identified two-drug combinations that could be more effective in killing GBM cells than conventional chemotherapeutic agents. The non-cancer drug Aspirin could potentially increase the cytotoxicity of TMZ in GBM patients.
Green synthesis of silver nanoparticles using Omani pomegranate peel extract and two polyphenolic natural products: characterization and comparison of their antioxidant, antibacterial, and cytotoxic activities
Authors: Saad Pasent Gharib , Castelino Rohan Daniel , Ravi Vimal , Al-Amri Issa Sulaiman , Khan Shah Alam
Published: April 2021

Background

Green synthesis of silver nanoparticles (AgNPs) has gained popularity due to the economical and eco-friendly approach associated with it. The aim of the study was to biosynthesize silver nanoparticles using pomegranate peel extract (PPE), quercetin (Q), and gallic acid (GA) and to evaluate their antioxidant, antimicrobial, and cytotoxic activities.

Results

A sharp color change from yellow to brown, appearance of a peak in a UV spectrum around 413–425 nm, and four intense peaks in XRD spectra matching with the reference silver crystal confirmed the formation of AgNPs. SEM and TEM analysis revealed particles to be mostly spherical with few aggregates. Average particle size distribution and zeta potential was found to be 43.6 nm and −18.01mV, 31.6 nm and −21.5 mV, and 21.7 nm and −27.9 mV for Q-AgNPs, P-AgNPs, and GA-AgNPs, respectively. P-AgNPs showed excellent in vitro antioxidant activity (84.85–89.20%) and cytotoxic activity (100% mortality). P-AgNPs and GA-AgNPs exhibited good antimicrobial activity against the four bacterial strains comparable to the reference antibiotics but Q-AgNPs failed to inhibit the growth of P. vulgaris.

Conclusions

Omani pomegranate peel extract seems to be a potential and alternative source for the simple, one pot, eco-friendly green synthesis of extracellular stable AgNPs. The synthesized nanoparticles have the potential to be developed as possible antimicrobial agents and antioxidants.

Graphical abstract
Teaching to Live, Finally
Authors: Kamuf Peggy
Published: April 2021

This article aligns moments from three of Derrida’s seminars and seeks to characterize the signature gesture of his teaching, which may be described as putting his teaching body, or corps enseignant, on an indivisible line supposed to divide mortal bodies from the bodies of institutions. It is a gesture that puts before us and on the line the mortal face of the “glorious body” sublated by philosophy and its teaching.
Regulation and Differentiation within Field-districts in Imaginal Discs of Drosophila
Authors: Hadorn E.
Published: April 2021

Genital imaginal discs of third instar larvae of Drosophila have been cut into medial, paramedial, or transverse parts of different sizes. The fragments were then implanted into the body cavity of a host larva. This medium provides the implants with ample nutritional material and hormones. The fragments thus differentiate their imaginal structures simultaneously with the metamorphosing host. A detailed analysis of the respective differentiations of the various parts has led to the following results and revealed the following properties of the different blastemata which are embodied in a genital disc (Hadorn et al., 1946, 1949,1950).
La Teneur des noyaux en acide désoxyribonucléique (DNA) au cours du développement, de la différenciation et de la croissance
Authors: Pasteels J.
Published: April 2021

Un des plus grands paradoxes de la cytologie actuelle est de pressentir le rôle fondamental que doit jouer le DNA dans le fonctionnement cellulaire et d’être incapable de l’exprimer de façon concrète.
Sea-urchin Development in the Light of Enzymic and Mitochondrial Studies
Authors: Gustafson Tryggve
Published: April 2021

The sea-urchin egg is characterized by a very high morphogenetic plasticity. Its trend in differentiation can in fact be controlled by means of various chemical agents. The development of the entoderm is thus favoured at the expense of that of the ectoderm by adding lithium ions to the sea-water (Herbst, 1892; Lindahl, 1936). Iodosobenzoic acid (Runnström & Kriszat, 1952) and thiocyanate (Herbst, 1892; Lindahl, 1936) have an opposite effect, i.e. they favour ectodermal development. The mechanism of segregation of the egg into the primary germ-layers might be elucidated if we knew more about the biochemical mode of action of these agents. A series of biochemical studies on lithium-treated and normal eggs and larva was therefore undertaken. The studies began on the level of amino acids and peptides and continued on the levels of enzymes and intracellular inclusions.

The total changes in the amino-acid composition of the egg were found to be rather small (Gustafson & Hjelte, 1951).
Influence of Implanted Micromeres on Reduction Gradients and Mitochondrial Distribution in developing Sea-urchin Eggs
Authors: Hörstadius Sven
Published: April 2021

Child (1936) has described reduction gradients in different stages of developing sea-urchin and starfish larvae. His results concerning the gradients in seaurchin mesenchyme blastulae and early gastrulae have been confirmed with Janus green. There exists a stronger vegetal (acropetal) reduction gradient and a weaker animal one, appearing later, in the normal whole larva. Isolated vegetal halves show a similar vegetal reduction gradient, but in most cases no animal gradient. In isolated animal halves the reduction starts in the thick plate of the enlarged apical tuft and no vegetal gradient appears. Micromeres implanted laterally in the animal part of a whole egg induce there a reduction centre. Four micromeres implanted into an isolated animal half induce a new vegetal reduction gradient and restrict the animal gradient, so that the reduction gradient system now resembles that of a normal egg. A comparison of isolated animal and vegetal halves shows that the reduction seems to start at the same time and to proceed simultaneously in both kinds of halves. We can, therefore, state that the metabolism in isolated animal halves is not identical with that of the same material when forming the animal part of a normal larva. A comparison of the reduction gradients in these different cases shows a remarkable conformity with the animal and vegetal morphogenetic gradients known from the analysis by fragmentation and transplantation experiments. (These results have been published in full, Horstadius, 1952.)
Changes in the Differentiation Level of Transplanted Tumours
Authors: Klein George
Published: April 2021

It has been well established that the serial transplantation of an originally highly differentiated mammalian neoplasm leads regularly to a gradual loss of most or all visible expressions of histological differentiation within the tumour tissue. In a tumour that has undergone many years of serial transplantation there can usually be detected no resemblance to the tissue of origin, but rather a similarity to early embryonic tissue. Simultaneously with these morphological changes a gradual increase in growth rate takes place. The completely anaplastic tumour with a long transplantation history grows usually at a very rapid rate as compared to the original spontaneous tumour. The growth rate of such tumours is, however, still inferior to, or, at its maximum, equal to the growth rate of embryos of the same species (Schrek, 1936; Klein & Révész, 1953), but has never been found to exceed it. These changes in growth rate and level of differentiation are usually coincident with a gradual decrease in the number of histocompatibility factors the presence of which in the implanted host is necessary for the progressive growth of the tumour. This decrease has been interpreted as somatic mutation (Strong, 1926), antigenic simplification (Gorer, 1948), or, more recently, as immunological selection from among the antigenic variants in a population of malignant cells, where the antigenic variants arise mainly as a consequence of disturbances in chromosome number (Hauschka, 1952).
Developmental Morphology of the Skin and Hair Follicles in Normal and in “Ragged” Mice
Authors: Slee J.
Published: April 2021

Ragged (Ra) is a semi-dominant mutant gene which was first reported by Carter & Phillips (1954). The adult morphology, the genetics, and the embryology of the mutant mice were described by Slee (1957 a, b). It was found that adult ragged heterozygotes (Ra+) had sparser coats than normal, many of their hair follicles being incompletely developed and non-functional. Ragged homozygotes (RaRa) were almost naked. Most of their pelage hair follicles were either absent, or abnormal and non-functional. Ra+ embryos could be identified from 16 days’ gestation by the retardation of their sinus hair-growth. RaRa embryos were characterized from 13 days’ gestation by the occurrence of a generalized subcutaneous oedema which persisted until birth, and also by retardation in the development of their sinus hairs and follicles. Pelage follicle primordia appeared at the normal time (14 days’ gestation) in Ra+ and RaRa embryos but subsequently developed slowly in RaRa embryos, especially when the oedema was pronounced.
An Experimental Study on the Relationships between Limb and Spinal Cord in the Embryo of Eleutherodactylus martinicensis
Authors: Hughes Arthur
Published: April 2021

A technique for grafting limb-buds in Eleutherodactylus is outlined, and the early development of the limb-nerves and of the ventral horns of the cord is described. Limb ablation of 6-day embryos results in marked reduction after 24 hours of the number of cells in the related ventral horn. Axon severance by amputation after 8 days first leads to chromatolysis of ventral horn cells followed by a period of degeneration some 10 days after the operation. If another limb-bud is grafted in place of a forelimb and becomes in-nervated, the loss in number of neurones in the related ventral horn is checked, mainly through the differentiation of fresh cells. When grafted at 5 days, a transplanted limb can maintain the number of ventral horn cells at 80 per cent, of the normal level. This effect declines with increasing age of operation, especially with hind limbs transplanted in the place of forelimbs. The proportion of innervations in batches of embryos bearing grafted limbs decreases with advancing age of the embryo at the time of operation. The host neurones lose their ability to innervate fresh territory as their axons become capable of regeneration along a previous path. When a hind limb bud is grafted above an undisturbed forelimb, it may be innervated from collaterals of the brachial nerve, fibres of which have already made contact with the ipsilateral limb. With such transplants, the frequency of innervation for operations at six days is much higher for autografts than for homografts when the animals are kept at 30° C. At a lower temperature, both types of graft are innervated equally readily. At the higher temperature, some degree of hypertrophy of the sympathetic system of the host is occasionally seen with transplanted hind limbs, or with homografts of front limbs.
The Developmental Capacity of Nuclei taken from Intestinal Epithelium Cells of Feeding Tadpoles
Authors: Gurdon J. B.
Published: April 2021

Nuclei from differentiated intestinal epithelium cells of feeding tadpoles and from control blastulae of Xenopus have been transplanted into enucleated recipient eggs. The differentiated state of the intestinal epithelium cells was shown by their possession of a striated border. The cleavage and embryonic development resulting from the intestinal epithelium cell nuclei was much more abnormal than that resulting from control blastula transfers. per cent. (10 out of 726) of the first transfers of intestine nuclei resulted in normal feeding tadpoles. The serial transplantation of nuclei and of their mitotic products showed that some of the intestine nuclei which promoted abnormal development after first transfer could nevertheless promote the formation of normal feeding tad-poles after serial transfer. The combined results of first transfers and of serial transfers demonstrated that at least 7 per cent, of the intestine nuclei possessed the genetic information required for the formation of normal feeding tadpoles. The cytological examination of eggs fixed soon after receiving transplanted nuclei indicated that the lack of cleavage and abortive cleavage following trans-plantation result from nuclei which were not effectively exposed to the recipient egg cytoplasm or which were transplanted at an unsuitable stage in their mitotic cycle. If these cases are excluded from the results, the intestine nuclei capable of promoting the formation of feeding tadpoles then constitute 24 per cent, of the remaining successful transfers. A similar interpretation of the experimental results shows that 70 per cent, of the successfully transplanted intestine nuclei have the genetic information required to form muscular response stage tadpoles with functional muscle- and nerve-cells. These results show that a nucleus can promote the formation of a differentiated intestine cell and at the same time contain the genetic information necessary for the formation of all other types of differentiated somatic cell in a normal feeding tadpole. It is concluded that the differentiation of a cell cannot be dependent upon the incapacity of its nucleus to give rise to other types of differentiated cell.
The effect of dimethylsulphoxide on the microtubular system of the mouse oocyte
Authors: Johnson Martin H. , Pickering Susan J.
Published: April 2021

The effect of dimethylsulphoxide (DMSO) on the organization of the microtubular system of the mouse oocyte has been examined. Exposure to DMSO causes the immediate appearance of multiple, cold-resistant microtubular asters associated with the foci of peri-centriolar material (PCM) normally present in the oocyte. More prolonged exposure to DMSO leads to progressive disassembly of the spindle, and as a result dispersal of the chromosomes and polar PCM foci occurs, and tubulin polymerization becomes confined to PCM-organized asters. Those astral microtubules located between the PCM foci and the cortex of the oocyte appear to be particularly stable, resulting in the development of lengthening radial bundles of microtubules between the PCM and the surface and the progressive movement of the PCM′foci towards the centre of the cell. In contrast, after activation of the oocyte the microtubules generated in the presence of DMSO remain located in a cortical mesh. The effects of DMSO do not appear to be fully reversible in most oocytes. We discuss the implications of these results both for the cytoplasmic organization of the oocyte and zygote, and for the attempts at cryopreservation of human oocytes for therapeutic use in infertility programmes.
An ECM substratum allows mouse mesodermal cells isolated from the primitive streak to exhibit motility similar to that inside the embryo and reveals a deficiency in the T/T mutant cells
Authors: Hashimoto Koichiro , Fujimoto Hirokazu , Nakatsuji Norio
Published: April 2021

The mesodermal cell layer is created by ingression and migration of the cells from the primitive streak region in mouse embryos on day 7 of pregnancy. In order to study the mechanisms of mesodermal cell migration during development, the mesodermal cells isolated from the primitive streak were cultured on various substrata, and cell behaviour and motility were analysed with a time-lapse video system. The mesodermal cells on the surface of extracellular matrix (ECM)-coated dishes (ECM produced by bovine corneal endothelial cells) showed extensive migration at a mean rate of approx. 50μmh-1. They also showed frequent cell division and exhibited contact paralysis of lamellipodia and contact inhibition of movement. On plastic or glass surfaces, however, the mesodermal cells became more flattened and less motile (approx. 20–30μm h-1). Cell shape and mean rate of movement on the ECM were very similar to those in situ, as investigated in a previous study (Nakatsuji, Snow & Wylie, 1986). Therefore, this culture condition could provide a useful experimental system for analysing the cellular basis of normal and abnormal morphogenetic movements in mouse embryos.

Employing such a culture system, we studied motility of the mesodermal cells from embryos homozygous for Brachyury (T) mutation, which are lethal at the midgestation stage in utero. Histological observations have suggested that anomalous morphogenesis of the T/T embryos may be brought about by defects in migration of the mesodermal cells derived from the primitive streak. When mesodermal cells from the primitive streak of the T/T mutant embryos on days 8–9 were cultured on the ECM substratum, mean rate of cell migration was significantly reduced compared to cells from normal embryos. Results support the idea of retarded migration by the mutant mesodermal cells as an important factor causing abnormalities in morphogenesis.
Changes in the distribution of tenascin during tooth development
Authors: Thesleff Irma , Mackie Eleanor , Vainio Seppo , Chiquet-Ehrismann Ruth
Published: April 2021

Tenascin is an extracellular matrix molecule that was earlier shown to be enriched in embryonic mesenchyme surrounding the budding epithelium in various organs including the tooth. In the present study tenascin was localized by immunohistology throughout the course of tooth development in the mouse and rat using polyclonal antibodies against chick tenascin. The results indicate that tenascin is expressed by the lineage of dental mesenchymal cells throughout tooth ontogeny. The intensity of staining with tenascin antibodies in the dental papilla mesenchyme was temporarily reduced at cap stage when the tooth grows rapidly and undergoes extensive morphogenetic changes. During the bell stage of morphogenesis, the staining intensity increased and tenascin was accumulated in the dental pulp even after completion of crown development and eruption. Tenascin was present in the dental basement membrane at the time of odontoblast differentiation. The dental papilla cells ceased to express tenascin upon differentiation into odontoblasts and tenascin was completely absent from dentin. It can be speculated that the remarkable expression of tenascin in the dental mesenchymal cells as compared to other connective tissues is associated with their capacity to differentiate into hard-tissue-forming cells.
Posterior apical ectodermal ridge removal in the chick wing bud triggers a series of events resulting in defective anterior pattern formation
Authors: Todt William L. , Fallon John F.
Published: April 2021

The ability of the anterior apical ectodermal ridge to promote outgrowth in the chick wing bud when disconnected from posterior apical ridge was examined by rotating the posterior portion of the stage-19/20 to stage-21 wing bud around its anteroposterior axis. This permitted contact between the anterior and posterior mesoderm, without removing wing bud tissue. In a small but significant number of cases (10/54), anterior structures (digit 2) formed spatially isolated from posterior structures (digits 3 and 4). Thus, continuity with posterior ridge is not a prerequisite for anterior-ridge function in the wing bud. Nevertheless, posterior-ridge removal does result in anterior limb truncation. To investigate events leading to anterior truncation, we examined cell death patterns in the wing bud following posterior-ridge removal. We observed an abnormal area of necrosis along the posterior border of the wing bud at 6-12 h following posterior-ridge removal. This was followed by necrosis in the distal, anterior mesoderm at 48 h postoperatively and subsequent anterior truncation. Clearly, healthy posterior limb bud mesoderm is needed for anterior limb bud survival and development. We propose that anterior truncation is the direct result of anterior mesodermal cell death and that this may not be related to positional specification of anterior cells. In our view, cell death of anterior mesoderm, after posterior mesoderm removal, should not be used as evidence for a role in position specification by the polarizing zone during the limb bud stages of development. We suggest that the posterior mesoderm that maintains the anterior mesoderm need not be restricted to the mapped polarizing zone, but is more extensively distributed in the limb bud.
Cytokeratin filament assembly in the preimplantation mouse embryo
Authors: Chisholm Julia C. , Houliston Evelyn
Published: April 2021

The timing, spatial distribution and control of cytokeratin assembly during mouse early development has been studied using a monoclonal antibody, TROMA-1, which recognizes a 55 000 Mr trophecto-dermal cytokeratin (ENDO A). This protein was first detected in immunoblots at the 4-cell stage, and became more abundant at the 16-cell stage and later. Immunofluorescence analysis revealed assembled cytokeratin filaments in some 8-cell blastomeres, but not at earlier stages. At the 16-cell stage, filaments were found in both polarized (presumptive trophecto-derm; TE) and apolar (presumptive inner cell mass; ICM) cells in similar proportions, although polarized cells possessed more filaments than apolar cells. By the late 32-cell, early blastocyst, stage, all polarized (TE) cells contained extensive filament networks whereas cells positioned inside the embryo tended to have lost their filaments. The presence of filaments in inside cells at the 16-cell stage and in ICM cells was confirmed by immunoelectron microscopy. Lineage tracing techniques demonstrated that those cells in the ICM of early blastocysts which did possess filaments were almost exclusively the progeny of polar 16-cell blastomeres, suggesting that these filaments were directly inherited from outside cells at the 16- to 32cell transition. Inhibitor studies revealed that proximate protein synthesis but not mRNA synthesis is required for filament assembly at the 8-cell stage. These results demonstrate that there are quantitative rather than qualitative differences in the expression of cytokeratin filaments in the inner cell mass and trophectoderm cells of the mouse embryo.
The wall of the chick embryo aorta harbours M-CFC, G-CFC, GM-CFC and BFU-E
Authors: Cormier Françoise , Dieterlen-Lièvre Françoise
Published: April 2021

In the 3-to 4-day avian embryo, after the first wave of haemopoiesis which derives in the yolk sac from haemopoietic stem cells formed in situ, haemopoietic cells emerge in an intraembryonic site, the wall of the aorta. In this paper, we demonstrate that this site harbours M-CFC, G-CFC, GM-CFC and late and early BFU-E. In serum-free medium, the growth of M-CFC and GM-CFC was strictly dependent on CSF present in fibroblast-conditioned medium (FCM). The growth of G-CFC was improved when FCM was replaced by a minute quantity of chicken and fetal calf serum. Like erythroid progenitors from bone marrow, BFU-E detected here required anaemic chicken serum to differentiate into haemoglobinized cells. The frequency of the different types of haemopoietic progenitors in the aortic population was very high: 80 M-CFC, 25 G-CFC, 4 GM-CFC and 70 BFU-E for 12 500 aorta cells, i.e. two to eight times more frequent than in the bone marrow population, depending on the type of progenitors.

Abbreviations: ACS, anaemic chicken serum; ANAE, alpha-naphthyl acetate esterase; BFU-E, burst-forming unit, erythroid; CAE, naphthol AS-D chloro-acetate esterase; CFU-E, colony-forming unit, erythroid; CFU-GEMM, colony-forming unit, granulocytic, erythroid, monocytic, megakaryocytic; CSF, colony-stimulating factor; FCM, fibroblast-conditioned medium; G-CFC, granulocytic, colony-forming cell; GM-CFC, granulocytic monocytic, colony-forming cell; M-CFC, monocytic, colony-forming cell.
Tectal pathways of regenerating goldfish optic axons after nasal or temporal half retinal removal
Authors: Humphrey Martin F. , Stuermer Claudia A. O.
Published: April 2021

The tectal pathways of regenerating goldfish optic axons are abnormal but not random. The relative proportion of temporal axons is highest in rostral tectum (65 %) drops in midtectum (31 %) and is very low in caudal tectum (4%). By contrast, nasal axons proceed into caudal tectum and are therefore relatively evenly distributed throughout the tectum. In this study, we have tested whether temporal axons are confined to rostral tectum by the presence of nasal axons in caudal tectum or whether they have a preference for rostral tectum regardless of other axons. We similarly tested whether nasal axons would grow preferentially into caudal tectum in the absence of temporal axons.

At the time of optic nerve section either the nasal or temporal half retina was removed. Either 35 or 70 days after nerve section, the regenerating optic axons were labelled with HRP and both their pathways and distribution determined in DAB-reacted tectal wholemounts.

In the absence of nasal axons, the relative density of temporal axons in rostral, mid and caudal tectum was 70 %, 28 % and 2 %, respectively. The corresponding values for nasal axons, in the absence of temporal axons, were 30 %, 40 % and 30 %, respectively. Thus, the overall distribution of nasal and temporal axons in the half retinal regenerates was similar to that of whole retinal regenerates, demonstrating that the retinotopic preferences of the axons were not dependent upon interaxonal interactions.

Thus, nasal and temporal axons obviously discriminate between rostral and caudal tectum despite pathway disorganization and the absence of axons from the opposite hemiretina. This is consistent with axonal growth being under the influence of positional markers in tectum.
Meiosis reinitiation in the mollusc Patella vulgata. Regulation of MPF, CSF and chromosome condensation activity by intracellular pH, protein synthesis and phosphorylation
Authors: Néant I. , Guerrier P.
Published: April 2021

The dependency of some key events of the cell cycle upon pH, phosphorylation and protein synthesis was investigated during meiosis reinitiation of Patella vulgata oocytes stimulated by ammonia. In this report, we show, through heterologous microinjection experiments, that a stable maturation promoting factor (MPF) is actually produced under these conditions. This factor, which may be amplified in recipient germinal vesicle (GV)-blocked oocytes of the starfish Asterias rubens, but not of Patella, remains present in the metaphase-1-blocked oocytes for at least 2·5 h. Using effective concentrations of the protein synthesis inhibitor emetine, we further demonstrate that the appearance of this factor does not depend on newly made proteins, whereas the maintenance of metaphase-1 conditions and chromosome condensation activity (CCA), which has been related to the simultaneous presence of a cytostatic factor (CSF), requires a continuous supply of new short-lived proteins.

Without this, the chromosomes decondense and the nuclear envelope reforms. Finally, we show that the entry into M-phase is accompanied by extensive protein phosphorylation, while the drug 6-dimethylami-nopurine (6-DMAP), which induces protein déphosphorylation without affecting protein synthesis or phosphoprotein phosphatase activity, produces the same cytological effects as emetine. The fact that the effect of 6-DMAP, both on protein phosphorylation and chromosome structure, is perfectly reversible indicates that Patella CSF activity must also be controlled at the posttranslational level, possibly through the activation of relevant protein kinases.
The appearance of glycoconjugates associated with cortical granule release during mouse fertilization
Authors: Lee S. H. , Ahuja K. K. , Gilburt D. J. , Whittingham D. G.
Published: April 2021

For the first time, we have shown with appropriately labelled lectins that fucosyl- and sialyl-rich glycoconjugates are released into the perivitelline space of the mouse oocyte after activation by the fertilizing spermatozoon or artificial activation by the calcium ionophore A23187 or ethanol. The glycoconjugates show a punctate distribution over the oocyte surface except for the microvilli-free area overlying the second meiotic spindle from which they are absent. Their appearance in the perivitelline space is associated with the release of the cortical granules suggesting that they represent part of the cortical granule exudate. Soon after the glycoconjugates appear, they begin to aggregate. The process continues until the beginning of cytokinesis at first cleavage when a single large aggregate is found within the cleavage furrow. Most of the labelled glycoconjugates disappear by the late 2-cell stage and no evidence was found for their presence during the later preimplantation period. This technique is suitable for monitoring the kinetics of the cortical reaction in mammalian oocytes and investigating the importance of the glycoconjugates in early preimplantation period.