bluuebunny/crossref_metadata_2025 huggingface dataset:
Environmental filtering and spatial processes equally contributed to macroinvertebrate metacommunity dynamics in the highly urbanized river networks in Shenzhen, South China
Authors: Liu Zhenyuan , Zhou Tingting , Cui Yongde , Li Zhengfei , Wang Weimin , Chen Yushun , Xie Zhicai
Published: April 2021

Background

Disentangling the relative roles of environmental filtering and spatial processes in structuring ecological communities is a central topic in metacommunity ecology. Metacommunity ecology in the temperate river ecosystems has been well developed, while less attention has been paid to subtropical urban river networks. Here, we examined the ecological factors and seasonal difference in structuring macroinvertebrates metacommunity assembly in the subtropical urban river networks in Shenzhen, South China.

Results

Our results revealed that there was no significant distinction of macroinvertebrate community composition among seasons, with only the relative abundance of Mollusca and Odonata significantly differed in both wet and dry seasons. One possible explanation was that most macroinvertebrates are generally pollution-tolerant taxa characterized with nonseasonal life cycle. In addition, distance-based redundancy analysis and variation partitioning approach revealed that metacommunity was determined equally by the environmental and dispersal-related factors. Further, our results showed that, although a slight temporal variation of relative contribution, the identity and explanation power of ecological factors were different among seasons. Specifically, stronger environmental filtering structuring community dynamics was observed in the dry than wet seasons, which might be owing to higher environmental heterogeneity under a low water-flow condition. Moreover, we detected that the influence of spatial processes was stronger in the wet than dry seasons, indicating an obvious dispersal processes due to high connectivity among sites.

Conclusion

Overall, our results revealed that environmental and spatial factors equally explained variations of macroinvertebrate metacommunity, implying the necessity of considering dispersal-related processes structuring ecological communities in river bioassessment programs. Moreover, degraded habitat conditions and water quality were the predominant factors that affected macroinvertebrate communities, indicating the significance and feasibility of improving local abiotic conditions to sustain local biodiversity. Further, our findings revealed the importance of seasonal dynamics of these urban river networks in structuring macroinvertebrate metacommunity. Thereby, our study improves the understanding of ecological processes governing macroinvertebrate metacommunity and underlines the idea that community ecology studies should go beyond the single snapshot survey in river networks.
Determination of antioxidant activity and phenolic compounds for basic standardization of Turkish propolis
Authors: Özkök Aslı , Keskin Merve , Tanuğur Samancı Aslı Elif , Yorulmaz Önder Elif , Takma Çiğdem
Published: April 2021

This study aimed to determine the standard amount of antioxidant content and compounds of the propolis for the standardization of propolis. For this purpose, the total flavonoids, total phenolic, CUPRAC antioxidant capacity content and the diversity of phenolic and flavonoid components of these propolis samples were found by HPLC determined at the 23 propolis samples which were collected different regions of Turkey. Beside that, the similarities and differences of these 23 provinces to each other according to their antioxidant capacities were investigated by multidimensional scaling analysis. The total flavonoid content in the propolis samples were determined between 21.28 and 152.56 mg CE/g. The total phenolic content in the propolis samples was found between 34.53 mg and 259.4 mg GAE/g. CUPRAC antioxidant capacity of the propolis samples and antioxidant range was found from 95.35 to 710.43 mg TE/g. Also, 4 flavonoid [Quercetin (min.1.12–max.4.14 mg/g), Galangin (min.0.72–max.40.79 mg/g), Apigenin (min.1.07–max.17.35 mg/g), Pinocembrin (min.1.32–max.39.92 mg/g] and 6 phenolic acid [Caffeic acid (min.1.20–max.7.6 mg/g), p-Coumaric acid (min.1.26–max.4.47 mg/g), trans-Ferulic acid (min.1.28–max.4.92 mg/g), Protocatechuic acid (1.78 mg/g), trans-Cinnamic acid (min.1.05–max.3.83 mg/g), Caffeic Acid Phenethyl Ester (CAPE) (min.1.41–max.30.15 mg/g)] components were detected as mg/g, in different ratios in propolis samples collected from different regions. The feature of this study, so far, is to have the maximum number of samples representing the Turkish propolis, and so is thought to help to national and international propolis standard workings.
Dietary inclusion of a partially defatted black soldier fly (Hermetia illucens) larva meal in low fishmeal-based diets for rainbow trout (Oncorhynchus mykiss)
Authors: Caimi Christian , Biasato Ilaria , Chemello Giulia , Oddon Sara Bellezza , Lussiana Carola , Malfatto Vanda Maria , Capucchio Maria Teresa , Colombino Elena , Schiavone Achille , Gai Francesco , Trocino Angela , Brugiapaglia Alberto , Renna Manuela , Gasco Laura
Published: April 2021

Background

Recent investigations highlighted that Hermetia illucens (BSF) larva meal can be a valuable alternative protein source for aquafeed production. In this study, in substitution of fishmeal, we used increasing inclusion levels of a partially defatted BSF larva meal in low fishmeal-based diets for rainbow trout (Oncorhynchus mykiss Walbaum) and we evaluated the related implications in terms of growth performance, physical characteristics, proximate and fatty acid (FA) compositions of the fillets, gut and liver histology, and diet digestibility. In a 131-day trial, 576 fish (100.1 ± 9.29 g) were randomly allotted to 24 tanks (24 fish/tank, 4 replicates/treatment). Six experimental diets were produced to have partial replacement of fishmeal (0, 10%, 20%, 30%, 40% and 50%) by increasing levels of BSF meal (0% [BSF0], 3% [BSF3], 6% [BSF6], 9% [BSF9], 12% [BSF12] and 15% [BSF15] on as fed basis, respectively).

Results

No differences were observed among the treatments for all the considered growth performance parameters. The viscero and hepato-somatic indexes showed significant differences among the treatments, with the highest values observed in the BSF15 group. No differences were recorded in terms of fillet’s physical characteristics, dry matter (DM), crude protein (CP) and ether extract (EE) contents. Total saturated and monounsaturated FA increased, while polyunsaturated FA (particularly n-3 FA) decreased while increasing the HI meal inclusion in the diet. Histopathology of liver and gut was not affected, whereas, in posterior gut, villi were higher in BSF6 and BSF9 compared to BSF3 fish. The apparent digestibility of DM, CP, EE and gross energy did not vary among the treatments.

Conclusions

These results suggest that a partially defatted BSF meal could be included up to 15% in low fishmeal-based diets for rainbow trout with no adverse effects on growth performance, fillet’s physical characteristics, gut and liver health, and diet digestibility. On the contrary, the fillet FA composition worsened while increasing the level of BSF meal in the diet.
A novel mouse model of heatstroke accounting for ambient temperature and relative humidity
Authors: Miyamoto Kazuyuki , Suzuki Keisuke , Ohtaki Hirokazu , Nakamura Motoyasu , Yamaga Hiroki , Yagi Masaharu , Honda Kazuho , Hayashi Munetaka , Dohi Kenji
Published: April 2021

Background

Heatstroke is associated with exposure to high ambient temperature (AT) and relative humidity (RH), and an increased risk of organ damage or death. Previously proposed animal models of heatstroke disregard the impact of RH. Therefore, we aimed to establish and validate an animal model of heatstroke considering RH. To validate our model, we also examined the effect of hydration and investigated gene expression of cotransporter proteins in the intestinal membranes after heat exposure.

Methods

Mildly dehydrated adult male C57/BL6J mice were subjected to three AT conditions (37 °C, 41 °C, or 43 °C) at RH > 99% and monitored with WetBulb globe temperature (WBGT) for 1 h. The survival rate, body weight, core body temperature, blood parameters, and histologically confirmed tissue damage were evaluated to establish a mouse heatstroke model. Then, the mice received no treatment, water, or oral rehydration solution (ORS) before and after heat exposure; subsequent organ damage was compared using our model. Thereafter, we investigated cotransporter protein gene expressions in the intestinal membranes of mice that received no treatment, water, or ORS.

Results

The survival rates of mice exposed to ATs of 37 °C, 41 °C, and 43 °C were 100%, 83.3%, and 0%, respectively. From this result, we excluded AT43. Mice in the AT 41 °C group appeared to be more dehydrated than those in the AT 37 °C group. WBGT in the AT 41 °C group was > 44 °C; core body temperature in this group reached 41.3 ± 0.08 °C during heat exposure and decreased to 34.0 ± 0.18 °C, returning to baseline after 8 h which showed a biphasic thermal dysregulation response. The AT 41 °C group presented with greater hepatic, renal, and musculoskeletal damage than did the other groups. The impact of ORS on recovery was greater than that of water or no treatment. The administration of ORS with heat exposure increased cotransporter gene expression in the intestines and reduced heatstroke-related damage.

Conclusions

We developed a novel mouse heatstroke model that considered AT and RH. We found that ORS administration improved inadequate circulation and reduced tissue injury by increasing cotransporter gene expression in the intestines.
Population-level mortality burden from novel coronavirus (COVID-19) in Europe and North America
Authors: Soneji Samir , Beltrán-Sánchez Hiram , Yang Jae Won , Mann Caroline
Published: April 2021

As of 31 January 2021, 63.9 million cases and 1.4 million deaths had been reported in Europe and North America, which accounted for 62.5% and 62.4% of the global total, respectively. Comparing the level of mortality across countries has proven difficult because of inherent limitations in the most commonly cited measures (e.g., case-fatality rates). We collected the cumulative number of confirmed deaths from COVID-19 by age in 2020 from the L’Institut National d’études Démographiques (INED) database and Statistics Canada for 15 European and North American countries. We calculated age-specific death rates and age-standardized death rates (ASDR) for each country over a 1-year period from 6 February 2020 (date of first COVID-19 death in Europe and North America) to 5 February 2021 using established demographic methods. We estimated that COVID-19 was the second leading cause of death behind cancer in England and Wales and France and the third leading cause of death behind cancer and heart disease in nine countries including the US. Countries with higher all-cause mortality prior to the COVID-19 experienced higher COVID-19 mortality than countries with lower all-cause mortality prior to the pandemic. The COVID-19 ASDR varied substantially within country (e.g., a 5-fold difference among the highest and lowest mortality states in Germany). Consistently strong public health measures may have lessened the level of mortality for some European and North American countries. In contrast, many of the largest countries and economies in these regions may continue to experience a high mortality level because of poor implementation and adherence to such measures.
Molecular identification of three entomopathogenic fungi infecting the brown plant hopper pest in Indonesia
Authors: Minarni Endang Warih , Soesanto Loekas , Suyanto Agus , Rostaman
Published: April 2021

Background

Brown plant hopper(Nilaparvata lugensStal.) a very damaging pest to rice crops. One of the efforts to control it is the use of entomopathogenic fungi (EPF). Three fungal local isolates found in Indonesia were effective in controlling the brown plant hopper pest. This study aimed to molecularly identify the 3 fungal isolates. Molecular identification is very important to get the exact identity of these fungi. The accuracy of EPF identification will greatly determine the success of control. Molecular identification is based on a partial genetic analysis of the internal transcribed spacer (ITS) locus of ribosomal fungal DNA.

Result

Morphology of the local isolates named J22 and J60 were identified asPaecilomycessp., while the isolate J34 was identified asBeauveriasp. The results of molecular identification of the isolates J22 and J60 were identified as the fungiLecanicillium saksenaeandSimplicilliumsp., while isolate J34 was identified asMyrotheciumsp. The results of literature search showed that the 3 fungi have never been previously reported to infect the brown plant hopper.

Conclusion

In Indonesia, 3 types of EPF, namelyL. saksenae,Simplicilliumsp., andMyrotheciumsp., were found having the potential to control the brown plant hopper pest.
Microbial community structure and composition is associated with host species and sex in Sigmodon cotton rats
Authors: Strickland Britton A. , Patel Mira C. , Shilts Meghan H. , Boone Helen H. , Kamali Arash , Zhang Wei , Stylos Daniel , Boukhvalova Marina S. , Rosas-Salazar Christian , Yooseph Shibu , Rajagopala Seesandra V. , Blanco Jorge C. G. , Das Suman R.
Published: April 2021

Background

The cotton rat (genus Sigmodon) is an essential small animal model for the study of human infectious disease and viral therapeutic development. However, the impact of the host microbiome on infection outcomes has not been explored in this model, partly due to the lack of a comprehensive characterization of microbial communities across different cotton rat species. Understanding the dynamics of their microbiome could significantly help to better understand its role when modeling viral infections in this animal model.

Results

We examined the bacterial communities of the gut and three external sites (skin, ear, and nose) of two inbred species of cotton rats commonly used in research (S. hispidus and S. fulviventer) by using 16S rRNA gene sequencing, constituting the first comprehensive characterization of the cotton rat microbiome. We showed that S. fulviventer maintained higher alpha diversity and richness than S. hispidus at external sites (skin, ear, nose), but there were no differentially abundant genera. However, S. fulviventer and S. hispidus had distinct fecal microbiomes composed of several significantly differentially abundant genera. Whole metagenomic shotgun sequencing of fecal samples identified species-level differences between S. hispidus and S. fulviventer, as well as different metabolic pathway functions as a result of differential host microbiome contributions. Furthermore, the microbiome composition of the external sites showed significant sex-based differences while fecal communities were not largely different.

Conclusions

Our study shows that host genetic background potentially exerts homeostatic pressures, resulting in distinct microbiomes for two different inbred cotton rat species. Because of the numerous studies that have uncovered strong relationships between host microbiome, viral infection outcomes, and immune responses, our findings represent a strong contribution for understanding the impact of different microbial communities on viral pathogenesis. Furthermore, we provide novel cotton rat microbiome data as a springboard to uncover the full therapeutic potential of the microbiome against viral infections.
Essais de cultures in vitro d’organes embryonnaires en milieux synthétiques
Authors: Wolff Etienne , Haffen Katy , Kieny Madeleine , Wolff Emilienne
Published: April 2021

Many embryonic organs have been cultivated in the ‘standard’ medium of E. Wolff and K. Haffen which contains glucose and embryo extract as nutrients. The researches reported in this paper give the first results of experiments designed to find out whether it is possible to replace this extract by definite mixtures of amino-acids and thus to realize the culture of organs in synthetic media. Several mixtures, containing a greater or lesser number of amino-acids (solutions B, C, and C1, see pp. 58-59), were added to a substrate consisting of agar, saline, and glucose. Vitamins and one stimulating substance (novocaine) were added to the media in some cases. The results of these experiments were compared with those in which the standard medium was used and with those in which organs were explanted on the basic substrate. Three kinds of organ were explanted: gonad, syrinx, and tibia from chick embryos of from 6 to 10 days’ incubation. The efficiency of the synthetic media was tested by three criteria: survival, differentiation, and growth of the explant. Gonads explanted in synthetic media either before or after the stage of sex differentiation begin or continue their differentiation. Morphogenesis and histogenesis are similar to those observed in the standard medium. Clear-cut evidence of growth is given by mitoses and by an increase in total N, estimated by an ultra-micro-Kjeldahl method, which indicates an assimilation of amino-acids by the explanted organs. Syrinxes were explanted both before and after the formation of the first pre-cartilaginous nodules of the tracheo-bronchial arches. They begin, or if already begun they complete, this first differentiation. Four to five pairs of arches are formed in latero-median succession. Growth of the organs was demon-strated by the presence of mitoses and by the increase in total N. Tibias explanted at the 8th day of incubation as cartilaginous rods continue to differentiate morphologically and histologically in synthetic media to which novocaine had been added as a stimulatory substance. Considerable growth in length and weight occurred, but no increase in total N was associated with it. Nevertheless in the presence of novocaine the catabolism of N is partly compensated for by the assimilation of amino-acids. Different organs, cultured in synthetic media, do not have the same needs for amino-acids, for vitamins, or for growth-promoting substances. Growth and differentiation are not necessarily correlated. One or the other of these phenomena may be favoured by certain changes in the medium. From the results reported in this paper it may be concluded that organs isolated in vitro are able to assimilate amino-acids from a synthetic medium for a limited period of growth and development.
Development and Structure of the Saccus Vasculosus of Scylliorhinus caniculus (L.)
Authors: Kamer J. C. Van de , Schuurmans A. J.
Published: April 2021

In Scylliorhinus caniculus the saccus vasculosus develops as an infundibular évagination. From an early stage of development there is a close contact between the tissue of Rathke’s pouch and the most caudal part of the infundibular evagination. During development the region of close contact shifts laterally to either side of the midline. The ventral wall of the évagination develops into neurohypophyseal tissue, the dorsal into saccus vasculosus epithelium. It is suggested that a process of continuing induction is responsible for the progressive transformation of the ventral wall into neurohypophyseal tissue; the dorsal wall on the contrary is free to follow its own tendency to develop into saccus epithelium. On the basis of developmental criteria, the homology of the saccus vasculosus with the processus infundibuli of mammals is suggested. It is suggested that in Teleosts the broad infundibular wall is homologous with the saccus évagination of Selachii and the processus infundibuli of mammals; and that it depends on the size of the region of contact between orohypophysis and infundibulum whether a large or a small saccus, or none at all, develops.
The Yolk-sacs of Erinaceus europea and Putorius furo
Authors: Morris B.
Published: April 2021

In Erinaceus, the hedgehog, a close relationship between the maternal blood and the embryonic tissues is established soon after implantation by the organization of vascular channels between the trophoblast and adjacent decidua. No comparable organization of vascular channels occurs in the uterine mucosa of Putorius, the ferret. In Putorius the omphaloidean placenta is avascular, and its probable inefficiency as an absorptive organ is reflected in the extremely low concentration of protein in the yolk-sac fluid. Fibrinogen was absent from the yolk-sac fluid in all the stages of pregnancy that were tested. In Erinaceus the omphaloidean placenta, like the allantochorionic placenta, is haemochorial in character. At its optimum development it is highly vascular. The concentration of protein in the yolk-sac fluid of the hedgehog is considerably higher than that in the ferret, but fibrinogen is absent except in very late stages of pregnancy, when the omphaloidean placenta is in an advanced stage of retrogression. It is probable that in these late stages the fibrinogen is of foetal origin. Despite the structural similarity which exists between the early omphaloidean placenta of the hedgehog and that of the rabbit, which is also haemochorial, there is no comparable rapid build up in the concentration of protein in the yolksac fluid of the former such as occurs in that of the latter. The permeability of the membranes must be very different in the two forms. Reichert’s membrane is formed late in development in the hedgehog, and it increases in thickness in very late stages of pregnancy. It appears to be of trophoblastic origin. Reichert’s membrane is absent in the ferret.
A Note on Abnormalities induced in Mouse Embryos by Trypan Blue
Authors: Waddington C. H. , Carter T. C.
Published: April 2021

Females of an inbred CBA strain of mice, kept in the presence of males, were injected with c.c. of 1 per cent, trypan blue solution 7 days after the detection of a copulation plug. In one series of experiments the animals were killed and the embryos recovered 1,2,3, ‘c., days after the injection; in another series the females were allowed to bring their embryos to term. The injected dye soon becomes accumulated in the yolk-sac, and a little later is visible in the region of the placenta. In many -day embryos the rate of development has been slowed down; the closure of the neural tube is abnormal, and the tube itself may show bends and kinks. Sub-epidermal blebs may be found in various regions. The rolling up of the embryo into a right-handed spiral, which normally occurs at about days, is very often affected, the posterior part of the body being deflected to the right. At the same time, the pericardium begins to be very markedly inflated; and it seems probable that the abnormal turning of the embryo is caused by the mechanical impediment presented by the hypertrophied pericardium. There is often a considerable dilation of the embryonic blood-vessels, particularly in the head; and fluids tend to escape from the vessels. There are often haematomata in the tail region. There is a high death-rate of embryos at 12-13 days. Those which survive to term usually show few abnormalities other than shortening or kinking of the tail. There is a marked shortage of females in the surviving young. This is presumably due to a differential death-rate, and since many deaths occur by 12 days, the females must be more sensitive than the males at a still earlier period, well before the time at which sexual differentiation takes place. It is suggested that the main effects of the dye are firstly a general inhibition of development and secondly a more specific effect on the body fluids and circulatory organs.
Axial abnormalities following disturbed growth in Mitomycin C-treated mouse embryos
Authors: Gregg B. C. , Snow M. H. L.
Published: April 2021

Primitive-streak and early-organogenesis-stage mouse embryos were treated with Mitomycin C (MMC) by intraperitoneal injection of pregnant females. Skeletal preparations of newborn pups were made and the axial skeleton examined. The treated animals showed a high incidence of:- (1) changed vertebral numers, (2) malformation of the vertebral column, (3) changed rib numbers and (4) rib abnormalities. These skeletal disturbances tend to be located more posteriorly with later MMC treatment. There is regional variation in the susceptibility of vertebrae to abnormal development. Extra elements may occur in any region of the spinal column and several unique combinations of numbers are reported. The possible origin of these abnormalities and their similarity to some human syndromes is discussed. It is suggested that they may be the consequence of altered growth profiles in interacting tissues during the restorative growth following MMC treatment.
Establishment of pluripotential cell lines from haploid mouse embryos
Authors: Kaufman M. H. , Robertson E. J. , Handyside A. H. , Evans M. J.
Published: April 2021

Eggs from 129 SvE and (C57BL × CBA)F1 hybrid female mice were activated partheno-genetically following their exposure to a 7 % solution of ethanol in PBS. Only the haploid class which developed a single pronucleus following second polar body extrusion was examined further. These eggs were transferred to suitable recipients and ‘delayed’ blastocysts subsequently recovered. The ‘delayed’ blastocysts were explanted into tissue culture and a total of four haploid-derived pluripotent cell lines established from individual embryos. Chromosome analysis of morulae revealed that over 80% contained only haploid mitoses. However, chromosome analysis of early passage cell lines revealed that all were diploid with a modal number of 40 chromosomes. When transplanted into syngeneic hosts, all lines formed well-differentiated teratocarcinomas. This technique provides a source of homozygous diploid cell lines of parthenogenetic origin.
Evidence that protein ingested by the rat visceral yolk sac yields amino acids for synthesis of embryonic protein
Authors: Freeman Stuart J. , Lloyd John B.
Published: April 2021

[3H]Leucine-labelled haemoglobin was prepared from rat reticulocytes incubated in the presence of [3H]leucine.

Conceptuses from 9-5-day pregnant rats were incubated in vitro for 48 h, with [3H]leucinelabelled haemoglobin present for the final 12, 8, 4, 2 or 0-5 hours. Radioactivity accumulated in visceral yolk sac and in embryonic tissue. When exposure to labelled haemoglobin was for only a short period before harvesting, all the radioactivity found in the embryo and most of that found in the visceral yolk sac was trichloroacetic acid-soluble (i.e. associated with free amino acid rather than with protein). After longer exposures the proportion of radioactivity that was acid-soluble decreased to minimum values of about 20 %.

SDS-polyacrylamide gel electrophoresis of the protein-associated radioactivity in visceral yolk sac and embryo was performed. After exposure to labelled haemoglobin for 1 h only prior to harvesting, the yolk sac contained a single peak of radioactivity coincident in mobility with haemoglobin. The embryo contained no protein-associated radioactivity. After exposure to labelled haemoglobin for 12 h, many protein bands in both yolk sac and embryo were radiolabelled.

Thus a single radiolabelled protein pinocytically captured by the visceral yolk sac can give rise to the presence of many labelled proteins in embryo and visceral yolk sac. These results indicate that the source protein underwent proteolytic digestion and that the amino acids generated were re-utilized for protein synthesis in both embryonic and visceral yolk-sac cells.
In vivo induction of granulopoiesis in visceral yolk-sac cells by foetal hepatic factors
Authors: Anckaert M. A. , Symann M.
Published: April 2021

In order to evaluate the hypothetical activity of foetal hepatic factors on putative yolk-sac haemopoietic stem cells we used the Double Diffusion Chamber (DDC) technique. The DDC were made of a regulator compartment, where foetal hepatic tissue was introduced and a test compartment where visceral yolk-sac cells were cultured. In this system a hepatic signal induced the yolk-sac stem cells to differentiate along the granulocytic pathway but did not stimulate yolk-sac CFUs growth. Contrary to CFUs originating from foetal liver or adult bone marrow, yolk-sac CFUs do not increase numerically in diffusion chamber culture.
Artificial heterokaryons of animal cells from different species
Authors: Harris H. , Watkins J. F. , Ford C. E. , Schoefl G. I.
Published: April 2021

A virus, inactivated by ultraviolet light, was used to fuse together cells from different species of vertebrate, and the resulting heterokaryons were examined by autoradiographic and cytological techniques. Heterokaryons could be made with both differentiated and undifferentiated cells: HeLa and Ehrlich ascites cells were studied as examples of undifferentiated cells; rabbit macrophages, rat lymphocytes and hen erythrocytes as examples of differentiated cells. These last three cells were chosen because in them, in varying degrees, the process of differentiation has resulted in suppression of the synthesis of DNA or of both DNA and RNA. This suppression was in all cases found to be reversible: the dormant nuclei could be induced to resume the synthesis of RNA or DNA or both when the differentiated cells were fused with a cell which normally synthesizes RNA and DNA. Observations on heterokaryons in which differentiated cells were fused with HeLa cells and with each other permitted certain general conclusions to be drawn about the regulation of nucleic acid synthesis in the heterokaryon. It was found that if either one of the parent cells normally synthesized RNA, RNA synthesis took place in both types of nuclei in the heterokaryon. If either of the parent cells normally synthesized DNA, DNA synthesis took place in both types of nuclei in the heterokaryon. If neither of the parent cells synthesized DNA, no DNA synthesis took place in the heterokaryon. In all cases where a cell which synthesized a particular nucleic acid was fused with one which did not, the active cell initiated the synthesis of this nucleic acid in the inactive partner. In no case did the inactive cell suppress synthesis in the active partner.

The nuclei of heterokaryons in which DNA synthesis took place underwent mitosis, and those nuclei which entered mitosis synchronously usually fused together. This process resulted in the progressive formation of mononucleate hybrid cells, which might thus contain within a single nucleus chromosomal complements derived from different species. These mononucleate hybrid cells were also capable of RNA and DNA synthesis, and many of them in turn underwent mitosis. At metaphase these cells showed, in various combinations, the chromosomal complements of the two parent cells. Mononucleate hybrid cells formed by the fusion of a large number of single cells did not appear to be capable of continued multiplication; but mononucleate cells containing one chromosomal set from each parent cell were still found to be undergoing mitosis many days after cell fusion.
A histochemical analysis of the proteins in the larval fat body of Sarcophaga bullata
Authors: Benson Katherine A. , Benson D. G.
Published: April 2021

A comparison has been made between the basic proteins of the nucleus and the cytoplasm in the larval fat body cell of Sarcophaga bullata. Basic protein was found in four regions of the cell: in the nucleolus, in association with the DNA of the nucleus, as a diffuse reticulum extending throughout the cytoplasm, and as a complement of granules distributed throughout the cytoplasm. Of these four regions only the nucleolar basic protein was apparently unaffected by the blocking reactions of deamination and acetylation when stained with alkaline fast green. The proteins of the other regions were seen to be arginine-rich, but contained a sufficient amount of lysine to be slightly affected by control procedures. The cytoplasmic granular basic protein, lysosomal in nature, and the diffuse basic protein of the cytoplasm, RNA-associated, stained in exactly the same manner as did the nuclear histone with the three techniques used for histone demonstration and with the Sakaguchi reaction. Control procedures had no effect on the intensity of the Sakaguchi reaction in any region of the cell where arginine was demonstrable. It is suggested that the term histone be reserved for DNA-associated basic protein, and that some of the non-specificity of histone staining may be resolved by applying auxiliary methods for the demonstration of acid hydrolases or associated nucleic acids.
The ultrastructure of the cement gland in xenopus laevis
Authors: Perry Margaret M. , Waddington C. H.
Published: April 2021

Alterations which occur during differentiation in the fine structure of the cement gland of the embryo of Xenopus laevis have been investigated. The organ anlage at the late neurula stage is composed of cuboidal cells of comparatively simple cytoplasmic structure. Coincident with the subsequent cellular elongation there is a formation of extensive arrays of functionally interrelated membrane systems, leading to the production of a mucin-like secretory substance. Although there is no direct structural continuity between the membranes of the endoplasmic reticulum and the Golgi apparatus, small vesicles which seem to originate from areas of agranular reticulum appear to transport material synthesized in the endoplasmic reticulum to the Golgi zone. Further elaboration of the product at the site of the Golgi material is suggested by the progressive increase in the quantity of the contents as the cisternae enlarge to form secretory granules.

Other notable features of the differentiating cells are microtubules and cytoplasmic filaments, many of which are oriented in the direction of cellular elongation. In suitably preserved specimens, large numbers of glycogen granules are present. The degenerating gland is characterized by the appearance of large autolytic vacuoles within the cytoplasm. Traces of the membrane systems are present and, in many cells, there remain large numbers of secretory granules.
An electron-microscopical and histochemical study of the oocyte periphery in bombus terrestris during vitellogenesis
Authors: Hopkins C. R. , King P. E.
Published: April 2021

The developing ovarian oocyte of Bombus terrestris has been studied using electron-microscopical, histochemical and autoradiographical techniques. In this publication only the events taking place in the peripheral ooplasm and in the surrounding follicular epithelium are described.

During vitellogenesis three forms of yolk arise. Most of the lipid yolk, together with large numbers of cytoplasmic organelles, is derived from the accompanying trophocyte cells during the earlier phases of yolk synthesis. Later, the larger albuminous yolk spheres which form the major part of the yolk arise at the oocyte periphery as a result of micropinocytotic activity. Yolk precursor materials taken up in this way are probably derived from the haemolymph. Glycogen yolk particles appear in the ooplasm in large numbers during thé later phases of yolk synthesis and arise from groups of small vesicles that have been derived largely from the trophocytes.

Two kinds of follicular epithelial cells occur. All the evidence suggests that the larger, more common form is extremely active during synthesis of albuminous yolk, although its precise role remains unclear. The narrower, less common form of follicular epithelial cell occurs only before albuminous yolk synthesis when its protein secretion is probably transferred to the oocyte.

After yolk synthesis the vitelline membrane is laid down in the intercellular space between the follicular epithelium and the oocyte, both of which contribute towards its formation. Next the chorion is laid down. Although only the earlier stages of its formation have been studied, it is apparent that the chorion is laid down in the intercellular space immediately adjacent to the vitelline membrane, and that it is formed by the follicular epithelium alone.
Formalin perfusion for correlative light- and electron-microscopical studies of the nervous system
Authors: Westrum L. E. , Lund R. D.
Published: April 2021

The formalin perfusion technique of Pease has been shown to be a satisfactory fixation method for both light and electron microscopy of the nervous system of rat and goldfish, so allowing correlative studies to be made on tissue from the same region of one brain.

Immediate post-osmication is not necessary for good ultrastructural preservation and even if it is delayed for 1 week, neuronal structure is adequate for all but detailed cytological work. Unosmicated tissue stained with uranyl acetate and lead citrate showed protein-like structures but not lipids, with membranes appearing as unstained bands. ‘Dark’ glial cells occurred near the surface of the cortex and could not be eliminated by prolonged fixation in situ. ‘ Dark’ neurons were found rarely.

It is suggested that, with this method of fixation, any poor preservation of tissue in direct light- and electron-microscopical correlative studies is due to the subsequent processing rather than the initial fixation. Preliminary results on material stained by a new Golgi-Kopsch modification and by reduced silver methods and subsequently examined with the electron microscope suggest that such damage is not extensive.
Studies on the Sex-Ratio and Related Phenomena
Authors: Parkes A. S.
Published: April 2021

(1) The sex-ratio of over 1000 albino mice born in 157 litters worked out at 118 males per 100 females. In the records which I was able to secure of 255 other mice the ratio was 133.8. Both these ratios are above other experimental determinations of the sex-ratio in mice. (2) The seasonal variation in the new breeding records here presented is quite in keeping with work on other mammals, i.e. the ratio is lowest in the height of the breeding season and highest at the extreme end. (3) The data relating to size of litter and sex-ratio show that abnormally small litters have a very low ratio compared with the average, and that abnormally large litters have a sex-ratio rather higher than the average. (4) The sex-ratio is known in some cases to fall with each successive pregnancy, but in the present case the ratio of first births is lower than in subsequent ones. (5) The interpretation of these facts, on the dual basis of the chromosome theory of sex determination and the sexually selective pre-natal mortality which is known to occur, is attempted.
On The Males and an Intersex-Like Specimen of The Parthenogenetic Saw-FlyPristiphora Pallipes, LEP
Authors: Peacock A. D.
Published: April 2021

Whilst conducting biological experiments on parthenogenesis in saw-flies during the year 1923, the writer obtained two males and an intersex-like specimen of the species Pristiphora pallipes, Lep., under somewhat peculiar circumstances. As this species appears almost completely thelytokous—the males being exceedingly rare—and as sexual abnormalities in it have never been observed before, and indeed, have only been recorded eight times previously among the Tenthredinidæ, opportunity is here taken of describing and discussing these special appearances. It will be necessary first to dwell upon the experimental conditions as it is not improbable that they may have had a direct bearing upon the results obtained, but in any circumstances the results are of interest in themselves.
Safety of image-guided radiotherapy in definitive radiotherapy for localized prostate cancer: a population-based analysis
Authors: Kuo Yao-Hung , Liang Ji-An , Chen Guan-Heng , Li Chia-Chin , Chien Chun-Ru
Published: April 2021

Objectives:

Image-guided radiotherapy (IGRT) is a recommended advanced radiation technique that is associated with fewer acute and chronic toxicities. However, one Phase III trial showed worse overall survival in the IGRT arm. The purpose of this observational study is to evaluate the impact of IGRT on overall survival.

Methods:

We used the Taiwan Cancer Registry Database to enroll cT1-4N0M0 prostate cancer patients who received definitive radiotherapy between 2011 and 2015. We used inverse probability treatment weighting (IPW) to construct balanced IGRT and non-IGRT groups. We compared the overall survival of those in the IGRT and non-IGRT groups. Supplementary analyses (SA) were performed with alternative covariates in propensity score (PS) models and PS approaches. The incidence rates of prostate cancer mortality (IPCM), other cancer mortality (IOCM), and cardiovascular mortality (ICVM) were also evaluated.

Results:

There were 360 patients in the IGRT arm and 476 patients in the non-IGRT arm. The median follow-up time was 50 months. The 5-year overall survival was 88% in the IGRT arm and 86% in the non-IGRT arm (adjusted hazard ratio [HR] of death = 0.93; 95% CI, 0.61–1.45; p = 0.77). The SA also showed no significant differences in the overall survival between those in the IGRT and non-IGRT arms. Both groups did not significantly differ in terms of IPCM, IOCM, and ICVM.

Conclusions:

The overall survival of localized prostate cancer patients who underwent IGRT was not inferior to those who did not.

Advances in knowledge:

We demonstrated that the overall survival for prostate cancer patients with IGRT was not worse than those who did not undergo IGRT; this important outcome comparison has not been previously examined in the general population.
Top health research funders’ guidance on selecting journals for funded research
Authors: Shamseer Larissa , Cobey Kelly D. , Page Matthew J. , Brehaut Jamie C. , Grimshaw Jeremy M. , Straus Sharon E. , Stewart Lesley A. , Moher David
Published: April 2021

Background: Funded health research is being published in journals that many regard as “predatory”, deceptive, and non-credible. We do not currently know whether funders provide guidance on how to select a journal in which to publish funded health research.

Methods: We identified the largest 46 philanthropic, public, development assistance, public-private partnership, and multilateral funders of health research by expenditure, globally as well as four public funders from lower-middle income countries, from the list at https://healthresearchfunders.org. One of us identified guidance on disseminating funded research from each funders’ website (August/September 2017), then extracted information about selecting journals, which was verified by another assessor. Discrepancies were resolved by discussion. Results were summarized descriptively. This research used publicly available information; we did not seek verification with funding bodies.

Results: The majority (44/50) of sampled funders indicated funding health research. 38 (of 44, 86%) had publicly available information about disseminating funded research, typically called “policies” (29, 76%). Of these 38, 36 (95%) mentioned journal publication for dissemination of which 13 (36.11%) offer variable guidance on selecting a journal, all of which relate to the funder’s open access mandate. Six funders (17%) outlined publisher requirements or features by which to select a journal. One funder linked to a document providing features of journals to look for (e.g. listed in the Directory of Open Access Journals) and to be wary of (e.g., no journal scope statement, uses direct and unsolicited marketing).

Conclusions: Few funders provided guidance on how to select a journal in which to publish funded research. Funders have a duty to ensure that the research they fund is discoverable by others. This research is a benchmark for funder guidance on journal selection prior to the January 2021 implementation of Plan S (a global, funder-led initiative to ensure immediate, open access to funded, published research).
eLabFTW as an Open Science tool to improve the quality and translation of preclinical research
Authors: Hewera Michael , Hänggi Daniel , Gerlach Björn , Kahlert Ulf Dietrich
Published: April 2021

Reports of non-replicable research demand new methods of research data management. Electronic laboratory notebooks (ELNs) are suggested as tools to improve the documentation of research data and make them universally accessible. In a self-guided approach, we introduced the open-source ELN eLabFTW into our lab group and, after using it for a while, think it is a useful tool to overcome hurdles in ELN introduction by providing a combination of properties making it suitable for small preclinical labs, like ours. We set up our instance of eLabFTW, without any further programming needed. Our efforts to embrace open data approach by introducing an ELN fits well with other institutional organized ELN initiatives in academic research.
Expanding the Chemical Information Science gateway
Authors: Medina-Franco José L.
Published: April 2021

As chemical information evolves, impacting many chemistry areas, effective ways to disseminate results by the scientific community are also changing. Thus, publication schemes adapt to meet the needs of researchers across disciplines to share high-quality data, information, and knowledge. Since 2015, the F1000Research Chemical Information Science (CIS) gateway has offered an open and unique model to disseminate science at the interface of chemoinformatics, bioinformatics, and several other informatic-related disciplines. In response to the evolution of chemical information science, the F1000Research CIS gateway has incorporated new members to the advisory board. It is also reinforcing and expanding the gateway areas with a particular focus on machine learning and metabolomics. The range of available article types, availability of data, exposure within complementary multidisciplinary F1000Research gateways, and indexing in major bibliographic databases increases the visibility of all contributions. As part of progressing open science in this field, we look forward to your high-quality contributions to the CIS gateway.
A pandemia e o pandemônio: uma análise sobre os desdobramentos de informações falsas em tempos de Covid-19.
Authors: Cordeiro Manfrin Bianca , Mastella Veronice
Published: April 2021

O presente artigo discute a fragilidade comunicacional na era da desinformação em uma crise humanitária, neste caso, a pandemia global da Covid-19. O estudo foi desenvolvido por meio de análise de conteúdo de notícias que relatam a circulação de informações inverídicas ou manipuladas sobre o coronavírus e que causaram desdobramentos negativos no período de março a dezembro de 2020. Para tanto, foram abordados conceitos comunicacionais, princípios deontológicos, contextos e reflexões sociais para melhor compreensão da problemática. A análise realizada neste estudo centrou-se em três episódios específicos: (1) a morte de mais de 700 pessoas no Irã por ingestão de álcool adulterado em decorrência do boato que a substância era a cura para a Covid-19; (2) o aumento de casos de ingestão e intoxicação por produtos de limpeza nos EUA após o presidente Donald Trump sugerir que as substâncias poderiam ser um possível tratamento para o coronavírus; (3) e a omissão de dados sobre o SARS-CoV-2 pela China no início da pandemia. Ambos os episódios serviram para ilustrar os perigos da desinformação, os tipos de desinformação existentes e a produção de danos a longo prazo que uma informação falsa pode causar. Com isso, o estudo reforça a importância de informações verificadas, bem como a pertinência do jornalismo nos tempos atuais e, assim, tem como pretensão contribuir para sua ressignificação.