In mesoscale eddies, the chemical properties and biological composition are different from those in the surrounding water due to their unique physical processes. The mechanism of physical–biological ...coupling in warm-core eddies is unclear, especially because no studies have examined the effects of environmental factors on bacteria and viruses. The purpose of the present study was to examine the influence of an anticyclonic warm eddy on the relationship between bacterial and viral abundances, as well as viral activity (viral production), at different depths. At the core of the warm eddy, the bacterial abundance (0.48 to 2.82 × 105 cells mL−1) fluctuated less than that outside the eddy (1.12 to 7.03 × 105 cells mL−1). In particular, there was a four-fold higher viral–bacterial abundance ratio (VBR) estimated within the eddy, below the layer of the deep chlorophyll maximum, than outside the eddy. An anticyclonic warm eddy with downwelling at its center may contribute to viruses being transmitted directly into the deep ocean through adsorption on particulate organic matter while sinking. Overall, our findings provide valuable insights into the interaction between bacterial and viral abundances and their ecological mechanisms within a warm eddy.
Although we have gained insight into the biological and biochemical effects of natural sunlight exposure on prokaryotes, little is known about sunlight exposure on natural virus communities. To ...address this question, an investigation of the effects of sunlight and dark treatments on viral communities, viral production and decay rates in Kenting coastal waters was conducted. The average rate of net viral production in the sunlight and dark treatment was 0.010 and 0.018 × 10
6
viruses mL
–1
h
− 1
, respectively. Furthermore, averaged value for viral decay in the sunlight treatment was 0.016 × 10
6
viruses mL
− 1
h
− 1
, a significant decrease (ca. 60%=((0.83 − 0.33)/(0.83 × 100%)) was observed in sunlight conditions, whereas no significant changes occurred in dark conditions. The gross viral production under sunlight conditions was slightly higher, however, non-significantly higher than that in the dark treatment. As a result, we suggest that sunlight damages a large portion of the natural viral community, affecting the role viruses play in food webs.
Viral dynamics are the result of the balance between the rates of viral production and decay. Here, we have carried out independent measurements of viral production and decay rates in different ...depths of the southern East China Sea in summer (August and October 2021). In this study, the prevalence of viral abundance at the surface waters (14.2~27.6 × 105 viruses mL−1) was significantly higher than the bottom of the euphotic zone (2.9~12.6 × 105 viruses mL−1). As for viruses to bacteria ratio (VBR) values, we found a wide variability both at the surface (1.4 to 3.2) and bottom of the euphotic zone (2.1 to 16.2). The results of our study showed that at all stations examined, in the southern East China Sea, the values of gross viral production (GVP) were significantly higher in the sunlit surfaces compared to the bottom of the euphotic zone. In particular, our analysis indicates that no significant viral decay rates (VD) were observed in some regions at the bottom of the euphotic zone. Here, we also provide a budget for viral abundance and net viral production in different regions in the southern East China Sea. The GVP or VD is not applicable in our case to explain VBR is high at bottom of the euphotic zone. The mechanisms underlying VBR uncoupling, viral production, and viral loss in marine systems are still being investigated.
There is no doubt that seagrass beds constitute one of the most productive ecosystems in shallow coastal waters. Despite this, picoplankton in seagrass ecosystems has received relatively little ...attention. The purpose of this study was to compare picoplankton growth and mortality rates between seagrass and unvegetated habitats using chamber incubations. We tested two main hypotheses: (i) incubation with seagrass would result in higher bacterial growth rates due to increased DOM release from seagrass photosynthesis, and (ii) Synechococcus spp. would be lower in the presence of seagrass due to competition for inorganic nutrients. Bacterial growth rates were higher in seagrass chambers (2.44 d–1) than in non-seagrass chambers (2.31 d−1), respectively, suggesting that organic carbon coming from the seagrass community may support bacterial production. Furthermore, the growth rate of Synechococcus spp. was significantly lower in the seagrass treatment than in the non-seagrass treatment, likely reflecting nutrient competition with the seagrass. Small-scale chambers proved to be a useful tool for studying the factors controlling spatial and temporal patterns of picoplankton across different habitats. Furthermore, future studies should examine picoplankton growth over a wider range of spatial scales in seagrass beds and adjacent unvegetated sediment.
A seagrass meadow is one of the most important ecosystems around the world, both economically and ecologically. An important feature of this ecosystem is the presence of large coastal seagrass beds, ...which dominate the primary production and contribute to the secondary productivity of the ecosystem. The microbial loop (consuming bacterial biomass by grazers and using seagrass-derived detritus by bacteria) may be an important mechanism for transferring seagrass-derived organic matter to aquatic food chains. The goal of this study is to gain a better understanding of how bacterial growth and mortality (grazing and viral lysis rates) differ in unvegetated meadow habitats and seagrass habitats. According to this study, DOC levels were higher in seagrass habitats (1685 g L−1) than in unvegetated water surroundings. The instantaneous growth rate of bacteria in seagrass habitats was 2.05 d−1, higher than that of unvegetated water. In a seagrass environment during the summer, we have found that viral lysis and grazing both result in similar mortality rates of bacteria during the summer season. It has been found, however, that bacterial production is controlled by the availability of resources (bottom-up control) in adjacent unvegetated waters, and is thus cycled internally within the bacteria–virus–DOC loop within those waters.
There is no doubt that seagrass beds constitute one of the most productive ecosystems in shallow coastal waters. Despite this, picoplankton in seagrass ecosystems has received relatively little ...attention. The purpose of this study was to compare picoplankton growth and mortality rates between seagrass and unvegetated habitats using chamber incubations. We tested two main hypotheses: (i) incubation with seagrass would result in higher bacterial growth rates due to increased DOM release from seagrass photosynthesis, and (ii) Synechococcus spp. would be lower in the presence of seagrass due to competition for inorganic nutrients. Bacterial growth rates were higher in seagrass chambers (2.44 dsup.–1) than in non-seagrass chambers (2.31 dsup.−1), respectively, suggesting that organic carbon coming from the seagrass community may support bacterial production. Furthermore, the growth rate of Synechococcus spp. was significantly lower in the seagrass treatment than in the non-seagrass treatment, likely reflecting nutrient competition with the seagrass. Small-scale chambers proved to be a useful tool for studying the factors controlling spatial and temporal patterns of picoplankton across different habitats. Furthermore, future studies should examine picoplankton growth over a wider range of spatial scales in seagrass beds and adjacent unvegetated sediment.
Direct comparisons of human and non-human primate brains can reveal molecular pathways underlying remarkable specializations of the human brain. However, chimpanzee tissue is inaccessible during ...neocortical neurogenesis when differences in brain size first appear. To identify human-specific features of cortical development, we leveraged recent innovations that permit generating pluripotent stem cell-derived cerebral organoids from chimpanzee. Despite metabolic differences, organoid models preserve gene regulatory networks related to primary cell types and developmental processes. We further identified 261 differentially expressed genes in human compared to both chimpanzee organoids and macaque cortex, enriched for recent gene duplications, and including multiple regulators of PI3K-AKT-mTOR signaling. We observed increased activation of this pathway in human radial glia, dependent on two receptors upregulated specifically in human: INSR and ITGB8. Our findings establish a platform for systematic analysis of molecular changes contributing to human brain development and evolution.
•Brain organoids preserve gene expression networks despite elevated metabolic stress•Chimpanzee organoids enable studies of the evolution of human brain development•Primary and organoid samples reveal 261 human-specific gene expression changes•Human radial glia exhibit increased mTOR activation compared to non-human primates
Comparisons of cerebral organoids between chimpanzees, macaques, and humans reveal gene duplications and cell-signaling alterations that explain developmental evolutionary differences that are unique to us as a species.
Epstein-Barr Virus (EBV) is associated with potentially fatal lymphoproliferations such as post-transplant lymphoproliferative disorder (PTLD), a serious complication of transplantation. The viral ...mechanisms underlying the development and maintenance of EBV+ B cell lymphomas remain elusive but represent attractive therapeutic targets. EBV modulates the expression of host microRNAs (miRs), non-coding RNAs that regulate gene expression, to promote survival of EBV+ B cell lymphomas. Here, we examined how the primary oncogene of EBV, latent membrane protein 1 (LMP1), regulates host miRs using an established model of inducible LMP1 signaling. LMP1 derived from the B95.8 lab strain or PTLD induced expression of the oncogene miR-155. However, PTLD variant LMP1 lost the ability to upregulate the tumor suppressor miR-193. Small molecule inhibitors (SMI) of p38 MAPK, NF-κB, and PI3K p110α inhibited upregulation of miR-155 by B95.8 LMP1; no individual SMI significantly reduced upregulation of miR-155 by PTLD variant LMP1. miR-155 was significantly elevated in EBV+ B cell lymphoma cell lines and associated exosomes and inversely correlated with expression of the miR-155 target FOXO3a in cell lines. Finally, LMP1 reduced expression of FOXO3a, which was rescued by a PI3K p110α SMI. Our data indicate that tumor variant LMP1 differentially regulates host B cell miR expression, suggesting viral genotype as an important consideration for the treatment of EBV+ B cell lymphomas. Notably, we demonstrate a novel mechanism in which LMP1 supports the regulation of miR-155 and its target FOXO3a in B cells through activation of PI3K p110α. This mechanism expands on the previously established mechanisms by which LMP1 regulates miR-155 and FOXO3a and may represent both rational therapeutic targets and biomarkers for EBV+ B cell lymphomas.
Ectopic pregnancies are the leading cause of maternal mortality in the first trimester, with an incidence of 5%–10% of all pregnancy-related deaths. Diagnosis of ectopic pregnancies is difficult due ...to clinical mimics and non-specific symptoms of abdominal pain and vaginal bleeding. The current standard for ectopic pregnancy diagnosis includes ultrasound imaging and β-human chorionic gonadotropin (β-hCG) monitoring. In addition to β-hCG, serum markers are being explored as a potential for diagnosis, with activin-AB and pregnancy-associated plasma protein A specifically showing promise. Other diagnostic methods include endometrial sampling, with dilation and curettage showing the highest specificity; however, frozen section reduces the diagnostic timeline which may improve outcomes. Treatment options for confirmed ectopic pregnancies include medical, surgical, and expectant management. Chosen treatment methodology is based on β-hCG levels, hematologic stability, and risk of ectopic pregnancy rupture. Current innovations in ectopic pregnancy management aim to preserve fertility and include laparoscopic partial tubal resection with end-to-end anastomosis and uterine artery embolization with intrauterine infusion of methotrexate. Psychological interventions to improve patient mental health surrounding ectopic pregnancy diagnosis and treatment are also valuable innovations. This literature review aims to bring light to current ectopic pregnancy diagnostics, treatments, and future directions.
Inflammatory pain, such as hypersensitivity resulting from surgical tissue injury, occurs as a result of interactions between the immune and nervous systems with the orchestrated recruitment and ...activation of tissue-resident and circulating immune cells to the site of injury. Our previous studies identified a central role for Ly6C
myeloid cells in the pathogenesis of postoperative pain. We now show that the chemokines CCL17 and CCL22, with their cognate receptor CCR4, are key mediators of this response. Both chemokines are up-regulated early after tissue injury by skin-resident dendritic and Langerhans cells to act on peripheral sensory neurons that express CCR4. CCL22, and to a lesser extent CCL17, elicit acute mechanical and thermal hypersensitivity when administered subcutaneously; this response abrogated by pharmacological blockade or genetic silencing of CCR4. Electrophysiological assessment of dissociated sensory neurons from naïve and postoperative mice showed that CCL22 was able to directly activate neurons and enhance their excitability after injury. These responses were blocked using C 021 and small interfering RNA (siRNA)-targeting CCR4. Finally, our data show that acute postoperative pain is significantly reduced in mice lacking CCR4, wild-type animals treated with CCR4 antagonist/siRNA, as well as transgenic mice depleted of dendritic cells. Together, these results suggest an essential role for the peripheral CCL17/22:CCR4 axis in the genesis of inflammatory pain via direct communication between skin-resident dendritic cells and sensory neurons, opening therapeutic avenues for its control.
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