The effect of intrauterine inflammation on mTOR signaling in mouse fetal brain

Fetuses exposed to an inflammatory environment are predisposed to long‐term adverse neurological outcomes. However, the mechanism by which intrauterine inflammation (IUI) is responsible for abnormal fetal brain development is not fully understood. The mechanistic target of rapamycin (mTOR) signaling pathway is closely associated with fetal brain development. We hypothesized that mTOR signaling might be involved in fetal brain injury and malformation when fetuses are exposed to the IUI environment. A well‐established IUI model was utilized by intrauterine injection of lipopolysaccharide (LPS) to explore the effect of IUI on mTOR signaling in mouse fetal brains. We found that microglia activation in LPS fetal brains was increased, as demonstrated by elevated Iba‐1 protein level and immunofluorescence density. LPS fetal brains also showed reduced neuronal cell counts, decreased cell proliferation demonstrated by low Ki67‐positive density, and elevated neuron apoptosis evidenced by high expression of cleaved Caspase 3. Furthermore, we found that mTOR signaling in LPS fetal brains was elevated at 2 hr after LPS treatment, declined at 6 hr and showed overall inhibition at 24 hr. In summary, our study revealed that LPS‐induced IUI leads to increased activation of microglia cells, neuronal damage, and dynamic alterations in mTOR signaling in the mouse fetal brain. Our findings indicate that abnormal changes in mTOR signaling may underlie the development of future neurological complications in offspring exposed to prenatal IUI.     

Mild manifestations of COVID-19 in healthcare workers

Medical staff treating Coronavirus Disease 2019 (COVID-19) patients are at high risk for exposure to Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), and many have been infected, which may cause panic among medical workers, their relatives, health professionals, and government leaders. We report the epidemiologic and clinical characteristics of healthcare workers and that the majority of infected medical staff had milder symptoms/conditions with a better prognosis than admitted patients. Timely improvement to medical staff’s working conditions such as allowing adequate rest and providing sufficient medical protection is extremely important.     

Arabidopsis RING E3 ubiquitin ligase JUL1 participates in ABA‐mediated microtubule depolymerization,stomatal closure,and tolerance response to drought stress

Ubiquitination is a critical post‐translational protein modification that has been implicated in diverse cellular processes, including abiotic stress responses, in plants. In the present study, we identified and characterized a T‐DNA insertion mutant in the At5g10650 locus. Compared to wild‐type Arabidopsis plants, at5g10650 progeny were hyposensitive to ABA at the germination stage. At5g10650 possessed a single C‐terminal C3HC4‐type Really Interesting New Gene (RING) motif, which was essential for ABA‐mediated germination and E3 ligase activity in vitro. At5g10650 was closely associated with microtubules and microtubule‐associated proteins in Arabidopsis and tobacco leaf cells. Localization of At5g10650 to the nucleus was frequently observed. Unexpectedly, At5g10650 was identified as JAV1‐ASSOCIATED UBIQUITIN LIGASE1 (JUL1), which was recently reported to participate in the jasmonate signaling pathway. The jul1 knockout plants exhibited impaired ABA‐promoted stomatal closure. In addition, stomatal closure could not be induced by hydrogen peroxide and calcium in jul1 plants. jul1 guard cells accumulated wild‐type levels of H₂O₂ after ABA treatment. These findings indicated that JUL1 acts downstream of H₂O₂ and calcium in the ABA‐mediated stomatal closure pathway. Typical radial arrays of microtubules were maintained in jul1 guard cells after exposure to ABA, H₂O₂, and calcium, which in turn resulted in ABA‐hyposensitive stomatal movements. Finally, jul1 plants were markedly more susceptible to drought stress than wild‐type plants. Overall, our results suggest that the Arabidopsis RING E3 ligase JUL1 plays a critical role in ABA‐mediated microtubule disorganization, stomatal closure, and tolerance to drought stress.     

耐盐碱促生菌的筛选及性能

盐分是影响作物生长最重要的因素,使用能促进植物生长的耐盐碱促生菌减轻盐胁迫引起的损害是一种农业上的有效方法。文中从盐碱地筛选得到7株耐盐细菌,并考察筛选菌株的产胞外聚合物(EPS)能力、降碱能力和产吲哚-3-乙酸(IAA)能力。经综合评价选出1株优势菌株DB01,菌株DB01产EPS能力为0.21 g/g,降碱能力为8.7%,产IAA的能力为8.97 mg/L。菌株经16S rRNA鉴定为海水盐单胞菌Halomonas aquamarina,并且有抑制香蕉枯萎病、番茄早疫病、大豆疫霉病、小麦纹枯病病原菌的能力,同时能够在盐胁迫下促进小麦幼苗的发芽率和根长。海水盐单胞菌Halomonas aquamarina DB01可为土壤微生物资源开发利用和盐碱地改良提供理论依据。     

基于白刺个体大小的生态化学计量模型

生态化学计量的提出为认识C、N、P耦合循环特征、驱动力及机制等提供了新方法,但植物在生长过程中的生态化学计量变化尚缺乏相关报道。本研究以唐古特白刺为对象,通过对白刺分株2017年当年生枝、2年生枝、大于2年生枝、叶、根和压条生物量及营养元素的测定,拟合了基于构件大小的元素总量,并推导了白刺各构件及整株依赖于个体大小的生态化学计量模型。结果表明: 推导模型能够反映植物在生长过程中的生态化学计量动态,老枝和压条均具有较高的N∶P与C∶P,叶、当年生枝和根均具有较低的N∶P与C∶P,白刺整株3种元素含量在生长过程中的累积速率为P>N>C。本研究结果符合现有的生长速率假说和异速生长理论,同时也可从侧面印证养分重吸收现象,该方法可作为分析植物生长过程中元素计量动态特征的一种有效途径。     

Whole‐genome resequencing reveals the pleistocene temporal dynamics of Branchiostoma belcheri and Branchiostoma floridae populations

Global climatic fluctuations governed the ancestral demographic histories of species and contributed to place the current population status into a more extensive ecological and evolutionary context. Genetic variations will leave unambiguous signatures in the patterns of intraspecific genetic variation in extant species since the genome of each individual is an imperfect mosaic of the ancestral genomes. Here, we report the genome sequences of 20 Branchiostoma individuals by whole‐genome resequencing strategy. We detected over 140 million genomic variations for each Branchiostoma individual. In particular, we applied the pairwise sequentially Markovian coalescent (PSMC) method to estimate the trajectories of changes in the effective population size (N_e) of Branchiostoma population during the Pleistocene. We evaluated the threshold of sequencing depth for proper inference of demographic histories using PSMC was ≥25×. The PSMC results highlight the role of historical global climatic fluctuations in the long‐term population dynamics of Branchiostoma. The inferred ancestral N_e of the Branchiostoma belcheri populations from Zhanjiang and Xiamen (China) seawaters was different in amplitude before the first (mutation rate = 3 × 10^?9) or third glaciation (mutation rate = 9 × 10^?9) of the Pleistocene, indicating that the two populations most probably started to evolve in isolation in their respective seas after the first or third glaciation of the Pleistocene. A pronounced population bottleneck coinciding with the last glacial maximum was observed in all Branchiostoma individuals, followed by a population expansion occurred during the late Pleistocene. Species that have experienced long‐term declines may be especially vulnerable to recent anthropogenic activities. Recently, the industrial pollution and the exploitation of sea sand have destroyed the harmonious living environment of amphioxus species. In the future, we need to protect the habitat of Branchiostoma and make full use of these detected genetic variations to facilitate the functional study of Branchiostoma for adaptation to local environments.     

Colonization Characteristics and Diversity of Arbuscular Mycorrhizal Fungi in the Rhizosphere of <i>Iris lactea</i> in Songnen Saline-alkaline Grassland

To understand arbuscular mycorrhizal (AM) fungi resources and develop AM fungal species in ornamental plants with saline-alkaline tolerances, Iris lactea, which grows in the Songnen saline-alkaline grassland with a high ornamental value, was selected as the experimental material, and the colonization characteristics of its roots and the AM fungal diversity in its rhizosphere were explored. The results of the observations and calculations of mycorrhizae from ten different samples showed that AM fungi colonized the roots of I. lactea and formed Arum-type mycorrhizal structures. There was a significant correlation between soil spore density and pH value, while the colonization rate showed a fluctuating trend with increasing pH values. The observed colonization intensities were of Levels II (1%–10%) or III (11%–50%), and the vesicle abundances were of grades A₂ or A₃ among different sites. AM fungi produced a large number of mycelia and vesicles in the roots of I. lactea after colonization. Thirty-seven species belonging to 15 genera of AM fungi were isolated from the rhizosphere of I. lactea and identified by morphological identification. Funneliformis and Glomus were the dominant genera, accounting for 21.79% and 20.85% of the total number, respectively. F. mosseae and Rhizophagus intraradices were isolated in all samples with importance values of 58.62 and 51.19, respectively. These results are expected to provide a theoretical basis for the analysis of the salt tolerance mechanism of I. lactea and for the discovery, exploration and further screening of AM fungal resources with salinity tolerances in saline-alkaline soils.     

At3g53630 encodes a GUN1-interacting protein under norflurazon treatment

Chloroplasts are semi-autonomous organelles, with more than 95% of their proteins encoded by the nuclear genome. The chloroplast-to-nucleus retrograde signals are critical for the nucleus to coordinate its gene expression for optimizing or repairing chloroplast functions in response to changing environments. In chloroplasts, the pentatricopeptide-repeat protein GENOMES UNCOUPLED 1 (GUN1) is a master switch that senses aberrant physiological states, such as the photooxidative stress induced by norflurazon (NF) treatment, and represses the expression of photosynthesis-associated nuclear genes (PhANGs). However, it is largely unknown how the retrograde signal is transmitted beyond GUN1. In this study, a protein GUN1-INTERACTING PROTEIN 1 (GIP1), encoded by At3g53630, was identified to interact with GUN1 by different approaches. We demonstrated that GIP1 has both cytosol and chloroplast localizations, and its abundance in chloroplasts is enhanced by NF treatment with the presence of GUN1. Our results suggest that GIP1 and GUN1 may function antagonistically in the retrograde signaling pathway.

     

Astragaloside IV alleviates atherosclerosis through targeting circ_0000231/miR-135a-5p/CLIC4 axis in AS cell model in vitro

Molecular and Cellular Biochemistry - Non-coding RNAs (ncRNAs) have shown to act as crucial mediators in atherosclerosis (AS) development. The purpose of our study was to explore the role of...