bluuebunny/crossref_metadata_2025 huggingface dataset:
Gregarine single-cell transcriptomics reveals differential mitochondrial remodeling and adaptation in apicomplexans
Authors: Salomaki Eric D. , Terpis Kristina X. , Rueckert Sonja , Kotyk Michael , Varadínová Zuzana Kotyková , Čepička Ivan , Lane Christopher E. , Kolisko Martin
Published: April 2021

Background

Apicomplexa is a diverse phylum comprising unicellular endobiotic animal parasites and contains some of the most well-studied microbial eukaryotes including the devastating human pathogens Plasmodium falciparum and Cryptosporidium hominis. In contrast, data on the invertebrate-infecting gregarines remains sparse and their evolutionary relationship to other apicomplexans remains obscure. Most apicomplexans retain a highly modified plastid, while their mitochondria remain metabolically conserved. Cryptosporidium spp. inhabit an anaerobic host-gut environment and represent the known exception, having completely lost their plastid while retaining an extremely reduced mitochondrion that has lost its genome. Recent advances in single-cell sequencing have enabled the first broad genome-scale explorations of gregarines, providing evidence of differential plastid retention throughout the group. However, little is known about the retention and metabolic capacity of gregarine mitochondria.

Results

Here, we sequenced transcriptomes from five species of gregarines isolated from cockroaches. We combined these data with those from other apicomplexans, performed detailed phylogenomic analyses, and characterized their mitochondrial metabolism. Our results support the placement of Cryptosporidium as the earliest diverging lineage of apicomplexans, which impacts our interpretation of evolutionary events within the phylum. By mapping in silico predictions of core mitochondrial pathways onto our phylogeny, we identified convergently reduced mitochondria. These data show that the electron transport chain has been independently lost three times across the phylum, twice within gregarines.

Conclusions

Apicomplexan lineages show variable functional restructuring of mitochondrial metabolism that appears to have been driven by adaptations to parasitism and anaerobiosis. Our findings indicate that apicomplexans are rife with convergent adaptations, with shared features including morphology, energy metabolism, and intracellularity.
MiR-126, IL-7, CXCR1/2 receptors, inflammation and circulating endothelial progenitor cells: The study on targets for treatment pathways in a model of subclinical cardiovascular disease (type 1 diabetes mellitus)
Authors: Coulson David J. , Bakhashab Sherin , Latief Jevi Septyani , Weaver Jolanta U.
Published: April 2021

Background

Type 1 diabetes (T1DM) is associated with premature cardiovascular disease (CVD) and a pro-inflammatory state whilst the proangiogenic miR-126-3p/-5p may play a role in CVD. Animal studies established miR-126 to be pro-angiogenic. We hypothesised miR-126-3p/-5p are reduced in T1DM whilst pro-inflammatory cytokines are increased.

Methods

29 well controlled, T1DM patients without CVD and 20 healthy controls (HCs) were studied. MiR-126-3p/-5p were assayed in plasma and peripheral blood mononuclear cells (PBMCs) whilst Chemokine C-X-C Receptor 1/2 (CXCR1/2) mRNA in PBMCs by real-time quantitative PCR. Cytokines were assayed by the Mesoscale Discovery. Ingenuity Pathway Analysis (IPA) was used to predict target genes, cellular functions and pathological states regulated by miR-126-3p/-5p. IPA generated both direct and indirect causations between different targets and analysed whether these effects would be inhibitory or stimulatory based on the published evidence.

Results

T1DM patients had a relatively good diabetic control (HbA1c = 7.4 ± 0.7% or 57.3 ± 7.6 mmol/mol). Homeostatic cytokine IL-7, pro-inflammatory cytokines IL-8 and TNF-α, and vascular endothelial growth factor-C (VEGF-C) were increased in T1DM, versus HCs; p = 0.008, p = 0.003, p = 0.041 and p = 0.013 respectively. MiR-126-5p was significantly upregulated in PBMCs in T1DM versus HCs; p = 0.01, but not in plasma. MiR-126-3p was unchanged. CXCR1/2 were elevated in T1DM versus HCs; p = 0.009 and p < 0.001 respectively. MiR-126-5p was positively correlated with CXCR1/2, and with HbA1c whilst negatively correlated with circulating endothelial progenitor cells (CD34+CD133+CD45dim) and fibronectin adhesion assay in a combined group of T1DM patients and HCs; p = 0.028 p = 0.049 p = 0.035 p = 0.047 and p = 0.004 respectively. IPA predicted miR-126-5p to be anti-inflammatory through the inhibition of chemokine C–C motif ligand 27, chymotrypsin-like elastase 2A and IL-7, whilst miR-126-3p had no direct anti-inflammatory effect. Simultaneously IPA predicted IL-7 as the most upstream cytokine target.

Conclusions

T1DM without apparent CVD or diabetic complications is an inflammatory state characterised not only by raised pro-inflammatory cytokines but also by increased receptor CXCR1/2 and miR-126-5p. MiR-126-5p upregulation may represent a compensatory response. Pro-miR-126-5p therapies or anti-IL-7 therapies may be a new option to reduce both inflammation and CVD risk in T1DM. Further research is required in a large prospective study in patients with T1DM.
Susceptibility to chronic immobilization stress‐induced depressive-like behaviour in middle‐aged female mice and accompanying changes in dopamine D1 and GABAA receptors in related brain regions
Authors: Cao Guofen , Meng Gaili , Zhu Li , Zhu Jie , Dong Nan , Zhou Xiaolan , Zhang Sumei , Zhang Yongai
Published: April 2021

Background

Middle-aged females, especially perimenopausal females, are vulnerable to depression, but the potential mechanism remains unclear. Dopaminergic and GABAergic system dysfunction is involved in the pathophysiology of depression. In the current study, we used 2-month-old and 11-month-old C57BL/6 mice as young and middle-aged mice, respectively. Chronic immobilization stress (CIS) was used to induce depressive-like behaviour, and the sucrose preference test (SPT), tail suspension test (TST) and forced swim test (FST) were used to assess these behaviours. We then measured the mRNA levels of dopamine receptor D1 (DRD1) and the GABAA receptors GABRA1, GABRB2 and GABRG2 in the nucleus accumbens (NAc) and prefrontal cortex (PFC).

Results

We found that immobility time in the FST was significantly increased in the middle-aged mice compared with the middle-aged control mice and the young mice. In addition, the preference for sucrose water was reduced in the middle-aged mice compared with the middle-aged control mice. However, CIS did not induce obvious changes in the performance of the young mice in our behavioural tests. Moreover, the middle-aged mice exhibited equal immobility times as the young mice in the absence of stress. Decreases in the mRNA levels of DRD1, GABRA1, and GABRB2 but not GABRG2 were found in the NAc and PFC in the middle-aged mice in the absence of stress. Further decreases in the mRNA levels of DRD1 in the NAc and GABRG2 in the NAc and PFC were found in the middle-aged mice subjected to CIS.

Conclusions

Our results suggested that ageing could not directly induce depression in the absence of stress. However, ageing could induce susceptibility to depression in middle-aged mice in the presence of stress. CIS-induced decreases in DRD1 and GABRG2 levels might be involved in the increase in susceptibility to depression in this context.
Biomarkers mining for spinal cord injury based on integrated multi-transcriptome expression profile data
Authors: Gong Chongcheng , Liu Lin , Shen Yang
Published: April 2021

Background

This study was aimed to discover more biomarkers associated with spinal cord injury (SCI) by constructing a competing endogenous RNA (ceRNA) network.

Methods

The transcriptome expression profile data related to SCI (GSE45006 GSE20907) were downloaded from GEO database. The differentially expressed RNAs (DERs), including lncRNAs, miRNAs, and mRNAs, between SCI and control groups were selected, which were then performed function enrichment analyses. Following that, a SCI-related ceRNA regulatory network was constructed. PCA analysis was performed on the genes constituting the ceRNA regulatory network directly related to SCI.

Results

In GSE45006 and GSE20907 datasets, there were respectively 3336 and 1453 DERs. Venn analysis showed that there were 429 DERs which had consistent differential expression direction. RGD1564534-miR-29b-5p relation pair and 103 miRNA-target regulatory pairs were integrated to construct the ceRNA regulatory network. Then a SCI-related ceRNA regulatory network including 8 mRNAs ofIFNGR1,STAT2,CYBB,NFATC1,FCGR2B,HMOX1,TLR4, andHK2, a lncRNA of RGD1564534, and a miRNA of miR-29b-5p was constructed. Additionally, two pathways, osteoclast differentiation, and HIF-1 signaling pathway, were involved in this network. PCA indicated the samples before and after injury can be significantly distinguished based on the genes in the ceRNA network.

Conclusion

A total of 8 SCI-related mRNAs have been identified in the ceRNA network, includingIFNGR1,STAT2,CYBB,NFATC1,FCGR2B,HMOX1,TLR4, andHK2.Moreover, RGD1564534 may serve as ceRNA by competitively binding to miR-29b-5p to regulate the expression of 8 SCI-related mRNAs. Therefore, these genes may serve as key biomarkers of SCI.
Characteristics associated with clinical response to Comano thermal spring water balneotherapy in pediatric patients with atopic dermatitis
Authors: Geat Davide , Giovannini Mattia , Barlocco Ezio Gabriele , Pertile Riccardo , Farina Stefania , Pace Manuela , Filippeschi Cesare , Girolomoni Giampiero , Cristofolini Mario , Baldo Ermanno
Published: April 2021

Background

Several studies have investigated the efficacy of balneotherapy in atopic dermatitis (AD), including a pediatric open randomized clinical trial conducted at the Comano thermal spring water center, which showed a significant reduction in AD severity and an improvement of the quality of life. However, so far many studies on balneotherapy in pediatric AD have included relatively small populations without identifying patients’ characteristics associated with their response. The aim of the present study was to identify any features associated with the clinical response to the Comano thermal spring water balneotherapy in a large cohort of pediatric AD patients.

Methods

An observational study was conducted on 867 children aged ≤16 years (females 50.5%, mean patient’s age 5.9 years, standard deviation ±3.6 years) with mild to severe AD who underwent balneotherapy at the Comano thermal spring water center (Comano, Trentino, Italy) from April to October 2014. Patients were stratified according to their disease severity, which was evaluated using five SCORing Atopic Dermatitis (SCORAD) categories before and immediately after a thermal spring water balneotherapy course. Potential characteristics associated with the patients’ clinical response to Comano thermal spring water balneotherapy were investigated.

Results

A statistically significant improvement in AD severity was observed after Comano thermal spring water balneotherapy (p < 0.0001). A significantly higher percentage of patients achieving improvement in AD severity was reported among children ≤4 years old (p < 0.0001) with early-onset AD (p < 0.0001), severe AD (p < 0.0001) or coexistent reported food allergies (p < 0.01). The therapy was well tolerated, and no relevant adverse effects were reported during the treatment course.

Conclusions

Comano thermal spring water balneotherapy is a safe complementary treatment for pediatric patients with AD, as it was able to reduce the disease severity, especially in children ≤4 years old, with early onset AD, severe AD or concomitant food allergies.
Assessing patients’ characteristics and treatment patterns among children with atopic dermatitis
Authors: Geat Davide , Giovannini Mattia , Barlocco Gabriele , Pertile Riccardo , Pace Manuela , Mori Francesca , Novembre Elio , Girolomoni Giampiero , Cristofolini Mario , Baldo Ermanno
Published: April 2021

Background

Atopic dermatitis (AD) is the most common immune-mediated skin disease in childhood. Several treatment options for pediatric AD, both topical and systemic, are currently available. We carried out a single-center observational study with the aim of describing characteristics and treatment patterns in pediatric AD patients.

Methods

The study included 867 patients aged ≤16 years (females 50.5%, mean patient’s age 5.9 years, standard deviation ±3.6 years) with a previous doctor-confirmed diagnosis of AD who underwent balneotherapy at the Comano Thermal Spring Water Center (Comano, Trentino, Italy) from April to October 2014.

Results

Among the patients included in the study, 41.2% had mild (SCORing Atopic Dermatitis, SCORAD 0-15), 43.6% moderate (SCORAD 16–40) and 15.2% severe AD (SCORAD > 40). A higher occurrence of reported food allergy was observed among children with more severe AD(p < 0.0001), while no association was found between AD severity and reported inhalant allergy or passive smoking (p = 0.15 and 0.92, respectively). Emollients (55.1%) and topical corticosteroids (TCS; 45.7%) were the main treatment options used in the previous month. The use of oral steroids and topical calcineurin inhibitors (TCI) was considerably less common (6.3 and 4.5%, respectively), while no patients were on systemic agents other than steroids. Among patients with severe AD, 9.8% had not used TCS, TCI or any systemic treatments. Moreover, 20.0% of the patients in the study population had followed elimination diets, although only 27.2% of them had a reported food allergy.

Conclusions

A significant difference in the prevalence of reported food allergy emerged across the different AD severity categories. Furthermore, although further data are necessary to confirm our findings, undertreatment in children with AD appeared to be very common, at least among those attending the Comano Thermal Spring Water Center. Moreover, many patients followed elimination diets in the absence of reported food allergy.
Correction to: Persistent left superior vena cava: clinical importance and differential diagnoses
Authors: Azizova Aynur , Onder Omer , Arslan Sevtap , Ardali Selin , Hazirolan Tuncay
Published: April 2021

An amendment to this paper has been published and can be accessed via the original article.
Bifurcation analysis in a diffusive phytoplankton–zooplankton model with harvesting
Authors: Wang Yong
Published: April 2021

A diffusive phytoplankton–zooplankton model with nonlinear harvesting is considered in this paper. Firstly, using the harvesting as the parameter, we get the existence and stability of the positive steady state, and also investigate the existence of spatially homogeneous and inhomogeneous periodic solutions. Then, by applying the normal form theory and center manifold theorem, we give the stability and direction of Hopf bifurcation from the positive steady state. In addition, we also prove the existence of the Bogdanov–Takens bifurcation. These results reveal that the harvesting and diffusion really affect the spatiotemporal complexity of the system. Finally, numerical simulations are also given to support our theoretical analysis.
Linear stability of blowup solution of incompressible Keller–Segel–Navier–Stokes system
Authors: Yan Yan , Li Hengyan
Published: April 2021

In this paper, we consider the linear stability of blowup solution for incompressible Keller–Segel–Navier–Stokes system in whole space$\mathbb{R}^{3}$R3. More precisely, we show that, if the initial data of the three dimensional Keller–Segel–Navier–Stokes system is close to the smooth initial function$(0,0,\textbf{u}_{s}(0,x) )^{T}$(0,0,us(0,x))T, then there exists a blowup solution of the three dimensional linear Keller–Segel–Navier–Stokes system satisfying the decomposition$$ \bigl(n(t,x),c(t,x),\textbf{u}(t,x) \bigr)^{T}= \bigl(0,0, \textbf{u}_{s}(t,x) \bigr)^{T}+\mathcal{O}(\varepsilon ), \quad \forall (t,x)\in \bigl(0,T^{*}\bigr) \times \mathbb{R}^{3}, $$(n(t,x),c(t,x),u(t,x))T=(0,0,us(t,x))T+O(ε),∀(t,x)∈(0,T∗)×R3,in Sobolev space$H^{s}(\mathbb{R}^{3})$Hs(R3)with$s=\frac{3}{2}-5a$s=32−5aand constant$0< a\ll 1$0<a≪1, where$T^{*}$T∗is the maximal existence time, and$\textbf{u}_{s}(t,x)$us(t,x)given in (Yan 2018) is the explicit blowup solution admitted smooth initial data for three dimensional incompressible Navier–Stokes equations.
Home range characteristics and diel patterns in space use of mutton snapper, Lutjanus analis, in St. Thomas, US Virgin Islands
Authors: Heidmann Sarah L. , Jossart Jonathan , Kimble Melissa , Nemeth Richard S.
Published: April 2021

Background

The movement ecology of mutton snapper Lutjanus analis is poorly understood despite their ecological and economic importance in the Caribbean. Passive acoustic telemetry was used to determine home ranges of six adult L. analis, including diel patterns, in Brewers Bay, St. Thomas, US Virgin Islands. Understanding long-term space use, including site fidelity and habitat usage, is necessary to implement effective and appropriate management actions for a species with extensive space and resource needs.

Results

Individual L. analis were tracked over an average period of 316 days (range 125–509 days) and showed high site fidelity to relatively small home ranges (mean ± SD: 0.103 ± 0.028 km2, range 0.019–0.190 km2) and core use areas with low overlap among individuals. Most home ranges had a habitat composition dominated by seagrass and to a lesser degree, coral reef and/or pavement. Nighttime activity spaces were distinct from but contained within daytime areas.

Conclusions

Mutton snapper showed strong site fidelity to home ranges in Brewers Bay. Two individuals that were absent from the array for more than a few hours were detected at separate arrays at spawning aggregation sites. This study expands upon knowledge of mutton snapper home range characteristics, highlights the importance of maintaining adjacent high-quality habitat types in any spatial management plan, and encourages the adoption of other types of management strategies, particularly for transient-aggregating species.
Intra-patient comparison of physiologic 68Ga-PSMA-11 and 18F-DCFPyL PET/CT uptake in ganglia in prostate cancer patients: a pictorial essay
Authors: Osman Medhat M. , Iravani Amir , Hofman Michael S. , Hicks Rodney J.
Published: April 2021

Background

Recent studies reported metabolic uptake in at least one of the evaluated ganglia in 98.5% of patients undergoing 68Ga -PSMA-11 and in 96.9% of patients undergoing 18F-DCFPyL PET/CT examination. We have observed different patterns of ganglion visualization with 18F-DCFPyL compared to 68Ga-PSMA-11. This includes more frequent visualization of cervical and sacral ganglia, which may be attributable to better imaging characteristics with 18F PET imaging.

Case presentation

This pictorial essay is to illustrate and compare, in the same patient, various representative cases of 68Ga-PSMA-11 and 18F-DCFPyL PET/CT uptake in ganglia at different anatomic locations, with different patterns and distribution of metabolic activity.

Conclusion

Reading physicians should be aware of the frequently encountered and occasionally different physiologic uptake of 68Ga-PSMA-11 and 18F DCFPyL in different ganglia.
Pain management in inflammatory bowel disease: feasibility of an online therapist-supported CBT-based self-management intervention
Authors: Sweeney Louise , Moss-Morris Rona , Czuber-Dochan Wladyslawa , Norton Christine
Published: April 2021

Background

Chronic pain is a poorly managed symptom of inflammatory bowel disease (IBD). Cognitive behavioural therapy (CBT) has an evidence base in functional gastrointestinal conditions and chronic pain. This study aimed to test the feasibility and acceptability of a 9-week online facilitator-supported CBT intervention, tailored for people with chronic IBD-related pain.

Design

A single-arm pre-post design with nested qualitative interviews was used. Twenty individuals with IBD and chronic pain were recruited through an online IBD charity and had consented to research in a previous survey or responded to an online charity advert. Individuals who indicated a pain-interference score of ≥ 4/10 (Brief Pain Inventory) and met inclusion criteria were invited to take part. Outcomes included recruitment and retention rates, pain interference and severity, quality of life (QoL) and psychosocial measures.

Results

Of 145 individuals contacted, 55 (37.9%) responded. Two individuals were recruited from the study advertisement. Twenty out of 57 (35.1%) met screening and eligibility criteria. Eighty-five percent of the sample engaged with intervention sessions and 55% completed at least 5/9 sessions. Eighty percent of recruited participants completed the post-intervention questionnaire at week 9. The mean score for overall acceptability was 43.4 (0–70). Qualitative feedback demonstrated the value of thought monitoring and facilitator support. Scores improved for QoL and pain self-efficacy and reduced for depression, anxiety, pain catastrophising and avoidance resting behaviour.

Conclusions

Online CBT for chronic IBD-related pain appears feasible and acceptable. The study suggests positive effects for improving QoL and reducing psychological distress; however, online and face-to-face recruitment methods are recommended and establishing efficacy through larger randomised controlled trials is required.
Bioinformatic analysis identifies potential biomarkers and therapeutic targets of septic-shock-associated acute kidney injury
Authors: Tang Yun , Yang Xiaobo , Shu Huaqing , Yu Yuan , Pan Shangwen , Xu Jiqian , Shang You
Published: April 2021

Background

Sepsis and septic shock are life-threatening diseases with high mortality rate in intensive care unit (ICU). Acute kidney injury (AKI) is a common complication of sepsis, and its occurrence is a poor prognostic sign to septic patients. We analyzed co-differentially expressed genes (co-DEGs) to explore relationships between septic shock and AKI and reveal potential biomarkers and therapeutic targets of septic-shock-associated AKI (SSAKI).

Methods

Two gene expression datasets (GSE30718 and GSE57065) were downloaded from the Gene Expression Omnibus (GEO). The GSE57065 dataset included 28 septic shock patients and 25 healthy volunteers and blood samples were collected within 0.5, 24 and 48 h after shock. Specimens of GSE30718 were collected from 26 patients with AKI and 11 control patents. AKI-DEGs and septic-shock-DEGs were identified using the two datasets. Subsequently, Gene Ontology (GO) functional analysis, Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis, and protein-protein interaction (PPI) network analysis were performed to elucidate molecular mechanisms of DEGs. We also evaluated co-DEGs and corresponding predicted miRNAs involved in septic shock and AKI.

Results

We identified 62 DEGs in AKI specimens and 888, 870, and 717 DEGs in septic shock blood samples within 0.5, 24 and 48 h, respectively. The hub genes of EGF and OLFM4 may be involved in AKI and QPCT, CKAP4, PRKCQ, PLAC8, PRC1, BCL9L, ATP11B, KLHL2, LDLRAP1, NDUFAF1, IFIT2, CSF1R, HGF, NRN1, GZMB, and STAT4 may be associated with septic shock. Besides, co-DEGs of VMP1, SLPI, PTX3, TIMP1, OLFM4, LCN2, and S100A9 coupled with corresponding predicted miRNAs, especially miR-29b-3p, miR-152-3p, and miR-223-3p may be regarded as promising targets for the diagnosis and treatment of SSAKI in the future.

Conclusions

Septic shock and AKI are related and VMP1, SLPI, PTX3, TIMP1, OLFM4, LCN2, and S100A9 genes are significantly associated with novel biomarkers involved in the occurrence and development of SSAKI.
Correction to: A study protocol for the development of a multivariable model predicting 6- and 12-month mortality for people with dementia living in residential aged care facilities (RACFs) in Australia
Authors: Bicknell Ross , Lim Wen Kwang , Maier Andrea B. , LoGiudice Dina
Published: April 2021

An amendment to this paper has been published and can be accessed via the original article.
Preoperative oral melatonin can reduce preoperative anxiety and postoperative analgesia in a dose-dependent manner
Authors: Lotfy Mohamed , Ayaad Mohamad
Published: April 2021

Background

Preoperative anxiety has deleterious effects on patients’ outcome through its influence on intraoperative requirements of anesthetics and analgesics (Bayrak et al., J Coll Physicians Surg Pak 29:868–873, 2019), postoperative (PO) pain intensity, and analgesia requirement, and may even increase PO morbidity and mortality after certain types of surgery. Melatonin is a methoxyindole synthesized and secreted principally by the pineal gland at night under control of an endogenous rhythm of secretion generated by the suprachiasmatic nuclei. The current study hypothesized that preoperative melatonin could reduce patients’ anxiety and reduce intraoperative (IO) and postoperative (PO) analgesic in a dose-dependent manner.

Results

Preoperative consultation was, to some extent, effective in reducing patients’ anxiety and apprehension. At 1 h after receiving premedication, Anxiety Specific to Surgery Questionnaire (ASSQ) scores were significantly lower in study groups in comparison to baseline scores and at 1 h scores of P group patients (patients who received 3 ml of plain distilled water), and this significant effect extended for 3-h PO. The reported ∆∆ASSQ between study groups was 25.9% between M2 (melatonin) and Z (midazolam) groups and 36.9% between groups M1 (received melatonin in a dose of 3 mg) and M2 (received melatonin in a dose of 6 mg). Preoperative anxiolytic therapy allowed reduction of PO pain scores and analgesia consumption with prolongation of duration till 1st request of rescue analgesia, and these effects were more pronounced with melatonin 6 mg in comparison to placebo, melatonin 3mg, or midazolam.

Conclusion

Preoperative melatonin is an appropriate policy for reduction of preoperative anxiety and provided reduction of PO anxiety, pain scores, and consumption of analgesia thus promoting early recovery and short PO hospital stay. Dose dependency was evident, and preoperative melatonin 6-mg dose provided satisfactory effect.
Enhancing the resolving ability of electrical resistivity tomography for imaging saltwater intrusion through improvements in inversion methods: A laboratory and numerical study
Authors: Goebel Meredith , Knight Rosemary , Kang Seogi
Published: April 2021

Mapping and monitoring saltwater intrusion are critical for the sustainable management of groundwater in coastal aquifers around the world. Increasingly, geophysical methods, such as electrical resistivity tomography (ERT), have been used to address these needs. We identify methods for the inversion of ERT data that would most accurately map the location and geometry of an intrusion wedge. This is accomplished using laboratory and synthetic experiments, with the classic representation of an intrusion wedge perpendicular to the coast. The laboratory experiments allow us to collect ERT data on a saltwater intrusion wedge in an environment in which we have supporting data that provided (1) the distribution of salinity within the tank with which to verify our inversion results, (2) the resistivity, porosity, and permeability of the porous medium, and (3) the transform between resistivity and salinity. The synthetic experiments allow exploration of issues of specific interest related to the presence of lithologic heterogeneity at a field site: the role of lithologic heterogeneity in introducing complexity into the resistivity-salinity relationship and the geometry of the saltwater intrusion wedge. We find that using a reference model with a good approximation of the wedge to inform the inversion greatly improves the ability of the resulting resistivity profile to map the wedge. Where there is no, or limited, lithologic heterogeneity, a parametric approach, which constrains the range of possible solutions by solving for a sharp interface between the saltwater and freshwater regions, is very effective at capturing the wedge location and geometry. Where there is lithologic heterogeneity, a hybrid between the parametric and informed inversion approaches is most effective, resolving the wedge with a high level of accuracy with little a priori information.
Distribution of Antigens in the Developing Newt Embryo
Authors: Clayton R. M.
Published: April 2021

Evidence is presented that a synthesis of antigenic material occurs in Triturus alpestris between the blastula and gastrula stage, before neurulation, and between neurulation and the formation of the tail-bud. During early morphogenesis and well before organogenesis the tissues exhibit a lack of antigenic uniformity. The behaviour of six antigenic fractions found in the gastrula have been studied both in their ontogeny and distribution up to the stage of the neurula. Three of these are to be found only after gastrulation. Ectoderm and archenteron roof contain fractions specific to themselves as well as containing some antigens in common. The ectoderm and neural plate of the neurula have some specificity relative to each other. An antigenic fraction specific to a given tissue type may be detected at a stage earlier than that at which this tissue first appears. Two antigenic fractions later characteristic of distinct tissues may coexist in their common precursor. A possible case of in vitro antigenic transformation is described. Antisera exhibit an irregularly cytotoxic effect when used in culture media. Partially absorbed antisera tend to cause abnormalities rather than death of whole embryos. There are indications that a certain degree of specificity in action of absorbed antisera occurs when used in culture media. Such specificity is more definite in the case of isolates of ectoderm and archenteron roof. A difference is found between the susceptibilities of blastulae and gastrulae to antisera which cannot be attributed to their difference in antigenic constitution but must depend on a change in the location of certain antigens or a change in permeability.
Rate of Regeneration in Planarians after Starvation
Authors: Brøndsted H. V.
Published: April 2021

Experiments with four planarian species, Dugesia tigrina, Planaria vitta, Dendrocoelum lacteum, and Bdellocephala punctata, indicate that starvation retards the rate of regeneration.
The Acceleration of Regeneration in Starved Planarians by Ribonucleic Acid
Authors: Agnes  , Brøndsted H. V.
Published: April 2021

Experiments indicate that RNA in concentrations of the order of 1:10,000 accelerates the rate of regeneration in starved planarians.
Les Effets de la centrifugation sur la blastula et la gastrula des Amphibiens : II. Étude comparative de la sensibilité en fonction des stades et des espèces
Authors: Pasteels J.
Published: April 2021

Dans le premier mémoire de cette série nous avons analysé le mécanisme par lequel des organes surnuméraires ou des axes embryonnaires secondaires peuvent apparaître aux dépens de l’ectoblaste, à la suite d’une centrifugation de la blastula ou de la gastrula.
Changes in Deoxyribonucleic Acid and Total Nitrogen in Planarian Worms during Starvation
Authors: Hoff-Jørgensen E. , Løvtrup Ebba , Løvtrup S.
Published: April 2021

The changes in total nitrogen and in deoxyribosides (DNA) have been followed during starvation of the planarian worm, Polycelis nigra. It was found that total nitrogen content after 60 days had been reduced to about 14 per cent, of its initial value. It is not possible to exclude with certainty the occurrence of any DNA loss, but it is clear that the loss, if any, is much smaller than the loss in nitrogen. The implications of these results for previous morphological investigations of the effects of starvation on planarian worms are discussed.
An Experimental Study of the Development of the Notochordal Sheath
Authors: Mookerjee Sivatosh
Published: April 2021

Pieces of presumptive notochord of amphibian embryos, carefully cleaned of other mesodermal cells, fail to form notochordal sheath when cultivated in isolation, but a sheath is formed around them when they are transplanted to any other site in the embryo in which they come in contact with mesoblastic cells. The sheath is absent from those regions of transplanted notochords which are in contact with non-mesodermal tissues such as endoderm. No sheath is formed around pieces of human hair placed in the position from which the notochord has been excised. If the presumptive notochord material is excised from late gastrulae of Trituras, a new notochord may be formed by regulation from the more lateral mesoderm. The regulated notochords are always provided with a sheath, and conversely the sheath is absent whenever the notochord is missing. It is concluded that the sheath is laid down by extra-chordal mesoblastic cells, which are induced to carry out this secretion by contact with the notochord. It is pointed out that this contradicts the conventional view held by most comparative anatomists, who have attributed the secretion of the sheath to the external layer of notochord cells (the ‘notochordal epithelium’).
The Development in vitro of the Embryonic Pineal Body of the Fowl
Authors: Vidmar Biserka
Published: April 2021

The pineal bodies of 4 and of 9-12 days old chick embryos were cultivated by Fell’s watchglass technique. The rate of differentiation was almost normal, but the growth-rate was retarded in vitro. The pineal body of 4 and of 9-12 days old embryonic fowl therefore possesses a capacity for self-differentiation which is independent of either bloodsupply or of endocrine stimulation.
The role of the Wolffian ducts in the formation of the sinus vagina: an organ culture study
Authors: Bok Gabriele , Drews Ulrich
Published: April 2021

In mammals formation of a sinus vagina is inhibited in the male by endogenous testosterone from the embryonic testes. To answer the question which morphogenetic events during formation of the vagina are influenced by testosterone, we explanted genital tracts of mouse embryos in the indifferent stage of development in organ culture. Half of the explants were treated with testosterone and therefore developed in male direction. The other half was kept without testosterone and developed constitutively in female direction. Since the antiMüller factor was not present, in both types of cultures the Müllerian ducts were preserved.

During female development the Müllerian ducts fused with the dorsolaterally apposed caudal segments of the Wolffian ducts. Thus the caudal segments of the Wolffian ducts were incorporated in the vaginal plate, while cranially the Wolffian ducts degenerated as expected.

During male development fusion between Müllerian and Wolffian ducts did not occur. Under the influence of testosterone the respective caudal segments of the Wolffian ducts were surrounded by dense mesenchyme and further male differentiation took place.

We conclude that the ‘sinus protrusions’ or ‘sinovaginal bulbs’ observed during development of the vagina, are in fact the caudal segments of the Wolffian ducts. They serve as a link between Müllerian ducts and urogenital sinus. Formation of a sinus vagina is prevented by testosterone simply by induction of male development in this area.
Time-dependent effects of α-amanitin on nuclear maturation and protein synthesis in mammalian oocytes
Authors: Osborn J. C. , Moor R. M.
Published: April 2021

The addition of α-amanitin to extrafollicular, cumulus-enclosed ovine oocytes at explantation inhibits meiotic maturation and prevents many of the changes in protein synthesis that normally accompany maturation. By contrast, these inhibitory effects are considerably reduced by either delaying the addition of the drug for 1-4 h or by denuding the oocytes of all associated cumulus cells at the onset of culture. The observations that the inhibitory effect of cordycepin on nuclear maturation is also time-dependent and cumulus-cell-dependent and that the oocyte is susceptible to cordycepin for longer than its sensitivity to α-amanitin are consistent with the differential effects of these drugs on RNA synthesis.

It is concluded that a transcriptional event at the onset of maturation is essential for the initiation of those changes in protein synthesis required for the regulation of nuclear and cytoplasmic maturation. It is uncertain, however, whether this transcriptional event occurs within the cumulus cells or within the oocyte.
Growth pattern of the sex ducts in foetal mouse hermaphrodites
Authors: Andersen C. Yding , Byskov A. G. , Grinsted J.
Published: April 2021

In this report the morphology of the gonads and the growth of the Wolffian and Müllerian duct in foetal mouse true hermaphrodites (16 days p.c.) have been studied and compared to that of normal mice. The ducts from the hermaphrodites were placed in one of five groups according to the proportion of male and female characteristic of the gonad.

When more than 85 % of the gonadal tissue was masculine, the Wolffian ducts showed the same percentage of cells in mitosis (mitotic index, MI) as normal males. The MI of the Wolffian ducts was lower, but constant, if the gonad contained between 0 and 85 % of testicular tissue. The number of Leydig cells in the gonads showed a linear relationship with the percentage of testicular tissue. Apparently, the MI of the Wolffian duct does not increase with increasing ‘maleness’ and with the number of Leydig cells. Four possibilities are put forward to explain the constant level of MI: (1) The Leydig cells of hermaphrodites may be deficient in producing testosterone. (2) The Leydig cells may produce testosterone at a normal rate but the epithelial cells of the Wolffian duct may not respond to increasing levels of testosterone by increasing their mitotic activity. (3) The presence of female gonadal tissue may directly or indirectly inhibit the mitotic activity of the epithelial cells of the Wolffian duct. (4) The epithelial cells of the Wolffian duct may respond to a low threshold level of testosterone, but maximal response is only triggered by a critical higher hormone level present only in group V.

In hermaphrodites, the Wolffian duct attached to a gonad without testicular tissue and without Leydig cells, has a MI which is significantly higher than in normal females. It is suggested that circulating testosterone from the contralateral gonad is responsible for this high MI.

In the Müllerian duct a mitotic index similar to that of the normal females was only found when the gonad contained from 0 to 15 % of testicular tissue. If a gonad contained more than 15 % of testicular tissue, the MI of the attached Müllerian duct was much lower equalizing that of normal males. No influence on the growth of the Müllerian duct could be observed from the contralateral gonad.
Lentoidogenesis from neural retina cells in culture is affected by interactive relationships between different cell types
Authors: Takagi Shin , Kondoh Hisato , Nomura Kazuya , Okada T. S.
Published: April 2021

By centrifugation in a Percoll gradient, two cell fractions were separated from cell populations harvested from 8-day cultures of neural retina cells of 3-5-day-old quail embryos. The heavy (H-) fraction contained mostly N-cells, which are considered to be putative neuronal cells, while the light (L-) fraction contained both E-cells, putative retinal glial cells, and N-cells. Determination of choline acetyltransferase activity in both fractions suggested that this enzyme is predominantly localised in N-cells. After replating the separated L-fraction for further culturing, frequent lentoidogenesis occurred from clusters of N-cells which, though few in number, were included in this fraction. Addition of H-fraction to L-fraction cells caused a significant increase in lentoidogenesis up to a ratio of N- to E-cells of 3:1. However, addition of excess H-fraction cells beyond this ratio inhibited lens differentiation. This difference in the expression of lens phenotypes resulting from the different ratios of H- and L-fraction was confirmed by monitoring the level of δ-crystallin in cultures. These results are discussed in the light of interactive relationships between N- and E-cells in the transdifferentiation of neural cells into lens in cell culture.
The organization and myofilament array of insect visceral muscles
Authors: Smith D. S. , Gupta B. L. , Smith Una
Published: April 2021

The cytological organization of three insect visceral muscles has been examined in the electron microscope. In each instance, the fibres were found to be striated, and the striation pattern has been shown to reflect the distribution along the sarcomere of two sets of myofilaments. In transverse sections of the fibre at the level of the A band, these muscles have been found to exhibit an unusual myofilament array in which each thick (myosin) filament is surrounded by twelve thin (actin) filaments rather than six, as in insect flight muscle and vertebrate skeletal muscle. The distribution of T-system tubules and cisternae of the sarcoplasmic reticulum in these visceral fibres is described, and compared with the corresponding membrane systems in other striated muscles.
Observations on the secretory processes in the corpus cardiacum of the stick insect, carausius morosus
Authors: Smith Una , Smith D. S.
Published: April 2021

The organization of the corpora cardiaca and of the nerve tracts linking these with the brain of the stick insect has been examined in the electron microscope. Particular attention has been paid to the appearance of neurosecretory products within the axons of the nervi corporis cardiaci, and within the cell processes of the intrinsic secretory neurons of the corpus cardiacum; these observations are considered to be an essential preliminary to a consideration of the mechanism of release of secreted products from the organ into the ambient haemolymph.

The corpus cardiacum contains cells of three main categories: axons of neurons located in the brain, intrinsic secretory neurons, and glial cells. Within the organ the cellular components form a loosely knit tissue incorporating ramifying extracellular spaces confluent with the haemolymph via the peripheral basement-membrane sheath of the organ. The present electron-microscopic account relates particularly to the mode of release of neurosecretory products into the extracellular milieu. This evidence indicates that the corpus cardiacum is the site of release of both extrinsic and intrinsic secretions, but does not support the suggestion that intrinsic neurosecretory materials synthesized within the corpus cardiacum are discharged via axon terminals at sites outside the corpus cardiacum. It is suggested that release of both extrinsic and intrinsic material takes place by fusion of the membrane surrounding the neurosecretory droplet with the plasma membrane of the nerve cell in regions where the glial sheath is absent.

The evidence on the mechanism of extrusion of materials initially secreted and sequestered within nerve cells and their processes is described and discussed in terms of present concepts of the passage of neural and other materials across plasma membrane boundaries.

It is stressed that, in this functionally versatile organ, the electron microscope may reveal the mechanism of release of active neurohumoral materials, but is at present unable to differentiate between the rich variety of these pharmacologically active products which affect numerous target organs throughout the body.
Chromosomes and nucleoli of the axolotl, Ambystoma mexicanum
Authors: Callan H. G.
Published: April 2021

Amongst the axolotl’s haploid complement of fourteen mitotic chromosomes, one of the four largest, with a greater arm asymmetry than the other three, shows a nucleolar constriction subterminally in its shorter arm. Low-temperature treatment causes further secondary constrictions to appear; these constrictions enable most of the mitotic chromosomes to be identified; the constrictions occur at similar sites in the chromosomes of tail-fin epithelial cells, hepatocytes, and brain cells.

Homology between the mitotic and oocyte (lampbrush) nucleolar organizers has been established, and thus the several hundred free nucleoli in oocytes are genetically related to the two nucleoli of diploid somatic interphases. During oocyte development the free nucleoli transform from solid structures to rings and back to solid structures again without detectable increase in number. During the contraction and aggregation of the lampbrush chromosomes within the oocyte nucleus as maturity approaches, in most axolotls the free ring-shaped nucleoli become stretched between the nuclear periphery and central chromosome group, and take on a characteristic beaded appearance. These transformations of the free nucleoli are largely paralleled by forms which nucleoli attached subterminally to the shorter arm of lampbrush chromosome III concurrently assume.

The question as to whether fully developed nucleoli detach from the organizer loci and add to the population of free nucleoli in oocytes remains undecided. It may well be that virtually all the DNA-generators of free nucleoli detach from the organizer loci before starting to carry out nucleolar functions, and before there is any significant accumulation of protein and RNA around them. If so, the variability in quantity of attached nucleolar material may not reflect different states in a nucleolar synthesis and detachment cycle, but rather variation in the number of nucleolar DNA Anlagen which happen to remain attached to the organizer loci after the synthesis and detachment of the great majority of the Anlagen has ceased.

In occasional oocytes the only chromosomal continuity maintained across the organizer locus consists of a nucleolar ‘ double bridge ‘; this indicates that the genetically persistent (i.e. chromosomal) organizer DNA bears the same structural relationship to neighbouring parts of a lampbrush chromosome as any other chromomere with its attendant pair of lateral loops.

The lampbrush chromosomes of the axolotl have been provisionally mapped. The centromeres are represented by short portions of chromosome axis without lateral loops, and there are two spheres close to the centromeres of both chromosome VI and chromosome XIII. Other recognition characters are inconspicuous or not very reliable, and features of the lampbrush chromosomes related to the low-temperature induced secondary constrictions of mitotic chromosomes have not been identified.
Some studies on the chromatin and cell wall of the mycetomal micro organisms of Sitophilus granarius (L.) (Coleoptera)
Authors: Singh S. B. , Musgrave A. J.
Published: April 2021

Cytochemical studies of the outer membranes and chromatinic material in the inherited, supposedly symbiotic mycetomal micro-organisms of Sitophilus granarius have revealed the presence of considerable amounts of DNA occurring as either consolidated dots or a spongy network. There is also evidence that, at times, the organisms are surrounded by cell walls.
Demonstration of extracellular space by freeze-drying in the cerebellar molecular layer
Authors: Harreveld A. Van , Malhotra S. K.
Published: April 2021

In electron micrographs of the molecular layer of the mouse cerebellum frozen within 30 sec of circulatory arrest and subsequently dried at − 79 °C an appreciable extracellular space was found between the axons of the granular cells. Tight junctions were regularly observed between pre- and postsynaptic structures and the enveloping glia cells. In micrographs of cerebellum frozen 8 min after decapitation the space between the axons was absent and tight junctions between the nerve fibres were almost exclusively encountered. The extracellular space of asphyxiated and non-asphyxiated tissue in electron micrographs of frozen-dried material is similar to the space in comparable tissues treated by freeze-substitution. These observations suggest that there is an appreciable amount of extracellular material in oxygenated, living tissue which is taken up by cellular elements during asphyxiation.