Engineering of NEMO as calcium indicators with large dynamics and high sensitivity.

Genetically encoded calcium indicators (GECIs) are indispensable tools for real-time monitoring of intracellular calcium signals and cellular activities in living organisms. Current GECIs face the challenge of suboptimal peak signal-to-baseline ratio (SBR) with limited resolution for reporting subtle calcium transients. We report herein the development of a suite of calcium sensors, designated NEMO, with fast kinetics and wide dynamic ranges (>100-fold). NEMO indicators report Ca2+ transients with peak SBRs around 20-fold larger than the top-of-the-range GCaMP6 series. NEMO sensors further enable the quantification of absolution calcium concentration with ratiometric or photochromic imaging. Compared with GCaMP6s, NEMOs could detect single action potentials in neurons with a peak SBR two times higher and a median peak SBR four times larger in vivo, thereby outperforming most existing state-of-the-art GECIs. Given their high sensitivity and resolution to report intracellular Ca2+ signals, NEMO sensors may find broad applications in monitoring neuronal activities and other Ca2+-modulated physiological processes in both mammals and plants.

Advancing electrocatalytic reactions through mapping key intermediates to active sites via descriptors.

Descriptors play a crucial role in electrocatalysis as they can provide valuable insights into the electrochemical performance of energy conversion and storage processes. They allow for the understanding of different catalytic activities and enable the prediction of better catalysts without relying on the time-consuming trial-and-error approaches. Hence, this comprehensive review focuses on highlighting the significant advancements in commonly used descriptors for critical electrocatalytic reactions. First, the fundamental reaction processes and key intermediates involved in several electrocatalytic reactions are summarized. Subsequently, three types of descriptors are classified and introduced based on different reactions and catalysts. These include d-band center descriptors, readily accessible intrinsic property descriptors, and spin-related descriptors, all of which contribute to a profound understanding of catalytic behavior. Furthermore, multi-type descriptors that collectively determine the catalytic performance are also summarized. Finally, we discuss the future of descriptors, envisioning their potential to integrate multiple factors, broaden application scopes, and synergize with artificial intelligence for more efficient catalyst design and discovery.

T6SS nuclease effectors in Pseudomonas syringae act as potent antimicrobials in interbacterial competition.

Type VI secretion system (T6SS) is a potent weapon employed by various Pseudomonas species to compete with neighboring microorganisms for limited nutrients and ecological niches. However, the involvement of T6SS effectors in interbacterial competition within the phytopathogen Pseudomonas syringae remains unknown. In this study, we examined two T6SS clusters in a wild-type P. syringae MB03 and verified the involvement of one cluster, namely, T6SS-1, in interbacterial competition. Additionally, our results showed that two T6SS DNase effectors, specifically Tde1 and Tde4, effectively outcompeted antagonistic bacteria, with Tde4 playing a prominent role. Furthermore, we found several cognate immunity proteins, including Tde1ia, Tde1ib, and Tde4i, which are located in the downstream loci of their corresponding effector protein genes and worked synergistically to protect MB03 cells from self-intoxication. Moreover, expression of either Tde1 or C-terminus of Tde4 in Escherichia coli cells induced DNA degradation and changes in cell morphology. Thus, our results provide new insights into the role of the T6SS effectors of P. syringae in the interbacterial competition in the natural environment. IMPORTANCE: The phytopathogen Pseudomonas syringae employs an active type VI secretion system (T6SS) to outcompete other microorganisms in the natural environment, particularly during the epiphytic growth in the phyllosphere. By examining two T6SS clusters in P. syringae MB03, T6SS-1 is found to be effective in killing Escherichia coli cells. We highlight the excellent antibacterial effect of two T6SS DNase effectors, namely, Tde1 and Tde4. Both of them function as nuclease effectors, leading to DNA degradation and cell filamentation in prey cells, ultimately resulting in cell death. Our findings deepen our understanding of the T6SS effector repertoires used in P. syringae and will facilitate the development of effective antibacterial strategies.

A Fluorination Strategy and Low-Acidity Anchoring Group in Self-Assembled Molecules for Efficient and Stable Inverted Perovskite Solar Cells.

Herein, we synthesized two donor-acceptor (D-A) type small organic molecules with self-assembly properties, namely MPA-BT-BA and MPA-2FBT-BA, both containing a low acidity anchoring group, benzoic acid. After systematically investigation, it is found that, with the fluorination, the MPA-2FBT-BA demonstrates a lower highest occupied molecular orbital (HOMO) energy level, higher hole mobility, higher hydrophobicity and stronger interaction with the perovskite layer than that of MPA-BT-BA. As a result, the device based-on MPA-2FBT-BA displays a better crystallization and morphology of perovskite layer with larger grain size and less non-radiative recombination. Consequently, the device using MPA-2FBT-BA as hole transport material achieved the power conversion efficiency (PCE) of 20.32 % and remarkable stability. After being kept in an N2 glove box for 116 days, the unsealed PSCs' device retained 93 % of its initial PCE. Even exposed to air with a relative humidity range of 30±5 % for 43 days, its PCE remained above 91 % of its initial condition. This study highlights the vital importance of the fluorination strategy combined with a low acidity anchoring group in SAMs, offering a pathway to achieve efficient and stable PSCs.

Travel Burden and Timely Linkage to Care Among People Newly Diagnosed with HIV Infection in South Carolina from 2005 to 2020.

This retrospective study explored the association between travel burden and timely linkage to care (LTC) among people with HIV (PWH) in South Carolina. HIV care data were derived from statewide all-payer electronic health records, and timely LTC was defined as having at least one viral load or CD4 count record within 90 days after HIV diagnosis before the year 2015 and 30 days after 2015. Travel burden was measured by average driving time (in minutes) to any healthcare facility visited within six months before and one month after the initial HIV diagnosis. Multivariable logistic regression models with the least absolute shrinkage and selection operator were employed. From 2005 to 2020, 81.2% (3,547 out of 4,366) of PWH had timely LTC. Persons who had longer driving time (adjusted Odds Ratio (aOR): 0.37, 95% CI: 0.14-0.99), were male versus female (aOR: 0.73, 95% CI: 0.58-0.91), had more comorbidities (aOR: 0.73, 95% CI: 0.57-0.94), and lived in counties with a higher percentage of unemployed labor force (aOR: 0.21, 95% CI: 0.06-0.71) were less likely to have timely LTC. However, compared to those aged between 18 and 24 years old, those aged between 45 and 59 (aOR:1.47, 95% CI: 1.14-1.90) or older than 60 (aOR:1.71, 95% CI: 1.14-2.56) were more likely to have timely LTC. Concentrated and sustained interventions targeting underserved communities and the associated travel burden among newly diagnosed PWH who are younger, male, and have more comorbidities are needed to improve LTC and reduce health disparities.

Single-cell transcriptome landscape of ovarian cells during primordial follicle assembly in mice.

Primordial follicle assembly in the mouse occurs during perinatal ages and largely determines the ovarian reserve that will be available to support the reproductive life span. The development of primordial follicles is controlled by a complex network of interactions between oocytes and ovarian somatic cells that remain poorly understood. In the present research, using single-cell RNA sequencing performed over a time series on murine ovaries, coupled with several bioinformatics analyses, the complete dynamic genetic programs of germ and granulosa cells from E16.5 to postnatal day (PD) 3 were reported. Along with confirming the previously reported expression of genes by germ cells and granulosa cells, our analyses identified 5 distinct cell clusters associated with germ cells and 6 with granulosa cells. Consequently, several new genes expressed at significant levels at each investigated stage were assigned. By building single-cell pseudotemporal trajectories, 3 states and 1 branch point of fate transition for the germ cells were revealed, as well as for the granulosa cells. Moreover, Gene Ontology (GO) term enrichment enabled identification of the biological process most represented in germ cells and granulosa cells or common to both cell types at each specific stage, and the interactions of germ cells and granulosa cells basing on known and novel pathway were presented. Finally, by using single-cell regulatory network inference and clustering (SCENIC) algorithm, we were able to establish a network of regulons that can be postulated as likely candidates for sustaining germ cell-specific transcription programs throughout the period of investigation. Above all, this study provides the whole transcriptome landscape of ovarian cells and unearths new insights during primordial follicle assembly in mice.

Place Visitation Data Reveals the Geographic and Racial Disparities of COVID-19 Impact on HIV Service Utilization in the Deep South.

BACKGROUND: The COVID-19 pandemic has posed unprecedented pressure to health care systems, and interrupted health care delivery and access including HIV care in the United States' Deep South, which endures a double epidemic of HIV and COVID-19. Ryan White programs cover HIV care services for over half of PLWH in the Deep South. Given the important role of Ryan White programs, examining the visitation changes to Ryan White facilities during the pandemic offers insights into the impact of the pandemic on HIV healthcare utilization. OBJECTIVES: Analyze the geographic distribution of HIV facility visitors at the county level before and during the pandemic in the nine US states of Deep South (Alabama, Florida, Georgia, Louisiana, Mississippi, North Carolina, South Carolina, Tennessee, Texas) to reveal the geographic and racial disparity in visitation disruption caused by the pandemic. METHODS: We first extracted mobile device-based visitation data for Ryan White HIV facilities in the Deep South during 2019 and 2020. To quantify the disruption in visitations during 2020, we calculated the visitation reduction rate (VRR) for each county, using 2019 data as the baseline. Next, we conducted a spatial analysis of the VRR values to uncover geographical disparities in visitation interruptions. To investigate racial disparities, we performed spatial regression analyses with VRR as the dependent variable, and the percentages of Black, Hispanic, and Asian populations as the independent variables. In this analysis, we controlled for potential confounders. RESULTS: Geographic disparities in visitation reduction were observed, with all nine Deep South states experiencing significant drops. Georgia experienced the highest visitation loss (VRR = -0.58), followed by Texas (-0.47), Alabama (0.47), and Tennessee (-0.46), while South Carolina had the smallest reductions (-0.11). All the regression models consistently revealed racial disparities in visitation interruption. That is, counties with a higher proportion of Black population tended to have higher RW facility visitation reductions. CONCLUSIONS: Our analysis revealed distinct geographic disparities in visitation interruptions at Ryan White HIV facilities in the Deep South during the COVID-19 pandemic in 2020. Furthermore, we found that the Black/African American population experienced a greater disruption at the county level in the Deep South during this period.

Understanding social risk factors of county-level disparities in COVID-19 tests per confirmed case in South Carolina using statewide electronic health records data.

BACKGROUND: COVID-19 testing is essential for pandemic control, and insufficient testing in areas with high disease burdens could magnify the risk of poor health outcomes. However, few area-based studies on COVID-19 testing disparities have considered the disease burden (e.g., confirmed cases). The current study aims to investigate socioeconomic drivers of geospatial disparities in COVID-19 testing relative to disease burden across 46 counties in South Carolina (SC) in the early (from April 1, 2020, to June 30, 2020) and later (from July 1, 2020, to September 30, 2021) phases of the pandemic. METHODS: Using SC statewide COVID-19 testing data, the COVID-19 testing coverage was measured by monthly COVID-19 tests per confirmed case (hereafter CTPC) in each county. We used modified Lorenz curves to describe the unequal geographic distribution of CTPC and generalized linear mixed-effects regression models to assess the association of county-level social risk factors with CTPC in two phases of the pandemic in SC. RESULTS: As of September 30, 2021, a total of 641,201 out of 2,941,227 tests were positive in SC. The Lorenz curve showed that county-level disparities in CTPC were less apparent in the later phase of the pandemic. Counties with a larger percentage of Black had lower CTPC during the early phase (ß = -0.94, 95%CI: -1.80, -0.08), while such associations reversed in the later phase (ß = 0.28, 95%CI: 0.01, 0.55). The association of some other social risk factors diminished as the pandemic evolved, such as food insecurity (ß: -1.19 and -0.42; p-value is < 0.05 for both). CONCLUSIONS: County-level disparities in CTPC and their predictors are dynamic across the pandemic. These results highlight the systematic inequalities in COVID-19 testing resources and accessibility, especially in the early stage of the pandemic. Counties with greater social vulnerability and those with fewer health care resources should be paid extra attention in the early and later phases, respectively. The current study provided empirical evidence for public health agencies to conduct more targeted community-based testing campaigns to enhance access to testing in future public health crises.

Genetic Diversity of Four Populations of Silver Carp (Hypophthalmichthys molitrix) Based on Mitochondrial Sequences.

Three mitochondrial DNA sequences (COI, ATP 8&6, and D-loop) were employed to assess the genetic diversity of four populations of silver carp from three main drainages in China, including the Yangtze River, the Amur River, and the Pearl River. As a result, 98 haplotypes were identified in combined sequences of COI, ATP8&6, and D-loop. A total of 196 variable sites and 116 parsimony-informative sites were observed. AMOVA based on assembled sequences indicated that 12.12% of the variation was among populations, while 87.88% of the variation was within populations. Additionally, the phylogenetic relationships of populations were depicted in a phylogenetic tree based on assembled sequences. Mismatch distribution analysis and the negative significant Fu's Fs values supported population expansion in all populations. Despite the high level of genetic diversity, the establishment of a state-level original breeding farm in the Amur River basin and the Pearl River basin may be an effective conservation strategy for the protection of local unique haplotypes.

In Situ Photoisomerization of an Azobenzene-Based Triple Helicate with a Prolonged Thermal Relaxation Time.

The phosphate-coordination triple helicates A2 L3 (A=anion) with azobenzene-spaced bis-bis(urea) ligands (L) have proven to undergo a rare in situ photoisomerization (without disassembly of the structure) rather than the typically known, stepwise "disassembly-isomerization-reassembly" process. This is enabled by the structural self-adaptability of the "aniono" assembly arising from multiple relatively weak and flexible hydrogen bonds between the phosphate anion and bis(urea) units. Notably, the Z→E thermal relaxation rate of the isomerized azobenzene unit is significantly decreased (up to 20-fold) for the triple helicates compared to the free ligands. Moreover, the binding of chiral guest cations inside the cavity of the Z-isomerized triple helicate can induce optically pure diastereomers, thus demonstrating a new strategy for making light-activated chiroptical materials.

ROS-NLRP3 signaling pathway induces sterile inflammation after thulium laser resection of the prostate.

The sterile inflammation (SI) of the urinary tract is a common problem requiring serious consideration after prostatectomy. This study mainly focuses on the role of the reactive oxygen species-NLR family, pyrin domain-containing 3 (ROS-NLRP3) signaling pathway in SI after thulium laser resection of the prostate (TmLRP). Urinary cytokines were determined in patients who received TmLRP, and heat shock protein 70 (HSP70) was detected in the resected tissues. The involvement of ROS signaling in HSP70-induced inflammation was explored in THP-1 cells with or without N-acetyl- l-cysteine (NAC) pretreatment. The function of NLRP3 and Caspase-1 was determined by Western blot analysis, enzyme-linked immunosorbent assay (ELISA), and polymerase chain reaction. These phenomena and mechanisms were verified by the beagle models that received TmLRP. Clinical urine samples after TmLRP showed high expression of inflammatory factors and peaked 3-5 days after surgery. The high expression of HSP70 in the resected tissues was observed. After HSP70 stimulation, the expression of ROS, NLRP3, Caspase-1, and interleukin-18 (IL-18) increased significantly and could be reduced by ROS inhibitor NAC. The expression of IL-1ß and IL-18 could be inhibited by NLRP3 or Caspase-1 inhibitors. In beagle models that received TmLRP, HSP70, NLRP3, Caspase-1, IL-1ß, and IL-18 were highly expressed in the wound tissue or urine, and could also be reduced by NAC pretreatment. Activation of the ROS-NLRP3 signaling pathway induces SI in the wound after prostatectomy. Inhibition of this pathway may be effective for clinical prevention and treatment of SI and related complications after prostatectomy.

Population Mobility and Aging Accelerate the Transmission of Coronavirus Disease 2019 in the Deep South: A County-Level Longitudinal Analysis.

Population mobility and aging at local areas contributed to the geospatial disparities in the coronavirus disease 2019 (COVID-19) transmission among 418 counties in the Deep South. In predicting the incidence of COVID-19, a significant interaction was found between mobility and the proportion of older adults. Effective disease control measures should be tailored to vulnerable communities.

Cloning and functional characterization of the geranylgeranyl diphosphate synthase(GGPPS)from Elizabethkingia meningoseptica sp.F2.

To date, there is no functional characterization of EmGGPPS (from Elizabethkingia meningoseptica sp.F2) as enzymes catalyzing GGPP. In this research, maltose-binding protein (MBP), disulfide bond A (DbsA), disulfide bond C (DbsC), and two other small protein tags, GB1 (Protein G B1 domain) and ZZ (Protein A IgG ZZ repeat domain), were used as fusion partners to construct an EmGGPPS fusion expression system. The results indicated that the expression of MBP-EmGGPPS was higher than that of the other four fusion proteins in E. coli BL21 (DE3). Additionally, using EmGGPPS as a catalyst for the production of GGPP was verified using a color complementation assay in Escherichia coli. In parallel with it, the enzyme activity experiment in vitro showed that the EmGGPPS protein could produce GGPP, GPP and FPP. Finally, we successfully demonstrated MK-4 production in engineered E. coli by overexpression of EmGGPPS.

The correlation between Demodex infestation and meibomian gland dysfunction at different ages.

BACKGROUND: This study aimed to explore the associations between Demodex infestation and the ocular surface characteristics of meibomian gland dysfunction (MGD) in different age groups, to further understand the effect of Demodex on MGD. METHODS: A total of 202 consecutive MGD patients aged 18 to 70 years were randomly recruited. All patients were divided into two groups based on their age: young patients (18-40 years) and elderly patients (41-70 years). The main observations were the different relationship between Demodex infestation and ocular surface and meibomian gland (MG) parameters in two age groups. We also compared ocular surface and MG parameters between the young and the elderly groups. Demodex infestation was diagnosed based on expert consensus in China. RESULTS: Our results indicated significant differences among young Demodex-positive, suspicious-positive, and negative patients in MG dropout (P = 0.000), plugging of MG orifices (P = 0.000), lid margin abnormality (P = 0.000), and meibum quality (P = 0.000). In elderly patients, there were significant differences among the Demodex-positive, suspicious-positive, and negative groups in terms of ocular surface disease index (OSDI) (P = 0.037), fluorescein tear film break-up time (FBUT) (P = 0.002), corneal fluorescein staining (CFS) (P = 0.036), MG dropout (P = 0.000), plugging of MG orifices (P = 0.008), lid margin abnormality (P = 0.000), and MG expression (P = 0.037). The mean number of mites in elderly Demodex-positive patients (10.64 ± 7.50) was greater than that of in young patients (7.60 ± 4.71) (P = 0.014). MG dropout (P = 0.000), plugging of MG orifices (P = 0.006), lid margin abnormality (P = 0.000), MG expression(P = 0.001), and meibum quality (P = 0.032) were more severe in elderly Demodex-positive patients. Additionally, FBUT (P = 0.005) was lower and tear film lipid layer thickness (LLT) (P = 0.001) was higher in the elderly. CONCLUSION: The effect of Demodex infestation on the ocular surface and MG parameters of MGD was different in patients of different ages. It is necessary to pay more attention to the diagnosis and treatment of Demodex infestation in MGD.

Transcriptional profiling of microglia in the injured brain reveals distinct molecular features underlying neurodegeneration.

Neurotrauma has been recognized as a risk factor for neurodegenerative diseases, and sex difference of the incidence and outcome of neurodegenerative diseases has long been recognized. Past studies suggest that microglia could play a versatile role in both health and disease. So far, the microglial mechanisms underlying neurodegeneration and potentially lead to sex-specific therapies are still very open. Here we applied whole transcriptome analysis of microglia acutely isolated at different timepoints after a cortical stab wound injury to gain insight into genes that might be dysregulated and transcriptionally different between males and females after cortical injury. We found that microglia displayed distinct temporal and sexual molecular signatures of transcriptome after cortical injury. Hypotheses and gene candidates that we presented in the present study could be worthy to be examined to explore the roles of microglia in neurotrauma and in sex-biased neurodegenerative diseases.

CAFs-derived MFAP5 promotes bladder cancer malignant behavior through NOTCH2/HEY1 signaling.

Cancer-associated fibroblasts (CAFs) are an important component of the tumor microenvironment and contribute to tumor cell proliferation and metastasis. Microfibrillar-associated protein 5 (MFAP5), a component of elastic microfibers and an oncogenic protein in several types of tumors, is secreted by CAFs. However, the role of MFAP5 in the bladder cancer remains unclear. Here, we report that MFAP5 is upregulated in bladder cancer and is associated with poor patient survival. Downregulation of MFAP5 in CAFs led to an impairment in proliferation and invasion of bladder cancer cells. Luciferase reporter assays and electrophoretic mobility shift assays (EMSA) showed QKI directly downregulates MFAP5 in CAFs. In addition, CAFs-derived MFAP5 led to an activation of the NOTCH2/HEY1 signaling pathway through direct interaction with the NOTCH2 receptor, thereby stimulating the N2ICD release. RNA-sequencing revealed that MFAP5-mediated PI3K-AKT signaling activated the DLL4/NOTCH2 pathway axis in bladder cancer. Moreover, downregulation of NOTCH2 by short hairpin RNA or the inactivating anti-body NRR2Mab was able to reverse the adverse effects of MFAP5 stimulation in vitro and in vivo. Together, these results demonstrate CAFs-derived MFAP5 promotes the bladder cancer proliferation and metastasis and provides new insight for targeting CAFs as novel diagnostic and therapeutic strategy.

A simple pillar[5]arene assembled multi-functional material with ultrasensitive sensing, self-healing, conductivity and host-guest stimuli-responsive properties.

Multi-functional materials have received wide attention due to their potential applications in various fields; therefore, developing a simple and easy strategy for the preparation of multi-functional materials is an interesting issue. In this work, a novel supramolecular gel, TP-QG, has been successfully constructed via the assembly of a simple methoxyl-pillar[5]arene host (TP) and a tripodal (tri-pyridine-4-yl)-amido-benzene guest (Q). Interestingly, TP-QG could act as a multi-functional material and showed strong fluorescence, good self-healing, host-guest stimuli-responsiveness and conductive properties. Due to these properties, TP-QG shows a fascinating application prospect. For instance, TP-QG could exhibit ultrasensitive fluorescence response for Fe3+ and F- in water via the fluorescence "ON-OFF-ON" pathway; the lowest detection limit (LOD) of TP-QG for Fe3+ was 2.32 × 10-10 M and the LOD of TP-QG-Fe for F- was 4.30 × 10-8 M. These properties permit TP-QG to act as not only a Fe3+ and F- sensor, but also an "ON-OFF-ON" fluorescence display material and an efficient logic gate. Meanwhile, the xerogel of TP-QG could remove Fe3+ from water, and the adsorption ratio was 98.68%; the xerogel of TP-QG-Fe could also remove F- from water; the removal ratio was about 87.92%. This work provides a feasible way to construct multi-functional smart materials by host-guest assembly.

Nematicidal effects of 2-methyl-aconitate isomerase from the phytopathogen Pseudomonas syringae MB03 on the model nematode Caenorhabditis elegans.

The pathogenicity of a common phytopathogenic bacterium, Pseudomonas syringae, against animal model hosts, such as mice and Caenorhabditis elegans, has been recently revealed. However, most of the virulence determinants associated with pathogenesis remain elusive. In the current study, we performed predictive analysis of virulence factors against C. elegans in the genome of the wild-type P. syringae strain MB03. Nine predicted nematicidal proteins were expressed and purified in recombinant Escherichia coli strains and were evaluated to define their toxicity against C. elegans in liquid killing assays. Next, we focused on one essential 2-methyl citrate cycle protein, PrpF03, which showed the highest lethal activity against C. elegans compared to the other tested proteins with a half lethal concentration (LC50) of 155.3 (123.4-176.6) µg mL-1 and a half lethal time (LT50) of 3.72 (1.64-4.85) days. Purified PrpF03 also caused adverse effects on the brood size, growth, and motility of C. elegans. Moreover, the PrpF03 protein exhibited pathological activity towards the intestinal tract of C. elegans. We surmise that the PrpF03 protein functions as a virulence factor when it blocks the average circulation of the 2-methyl citrate cycle of C. elegans by accumulating 2-methyl citrate in the gut of C. elegans, which damages and restrains the growth of intestinal tissues that ultimately kill C. elegans. The discovery of specific nematicidal activities of PrpF03 provides a better understanding of the mechanisms of phytopathogenic P. syringae against nematodes and could aid in developing nematode pest-controlling agents in agriculture.

Spatial-Temporal Relationship Between Population Mobility and COVID-19 Outbreaks in South Carolina: Time Series Forecasting Analysis.

BACKGROUND: Population mobility is closely associated with COVID-19 transmission, and it could be used as a proximal indicator to predict future outbreaks, which could inform proactive nonpharmaceutical interventions for disease control. South Carolina is one of the US states that reopened early, following which it experienced a sharp increase in COVID-19 cases. OBJECTIVE: The aims of this study are to examine the spatial-temporal relationship between population mobility and COVID-19 outbreaks and use population mobility data to predict daily new cases at both the state and county level in South Carolina. METHODS: This longitudinal study used disease surveillance data and Twitter-based population mobility data from March 6 to November 11, 2020, in South Carolina and its five counties with the largest number of cumulative confirmed COVID-19 cases. Population mobility was assessed based on the number of Twitter users with a travel distance greater than 0.5 miles. A Poisson count time series model was employed for COVID-19 forecasting. RESULTS: Population mobility was positively associated with state-level daily COVID-19 incidence as well as incidence in the top five counties (ie, Charleston, Greenville, Horry, Spartanburg, and Richland). At the state level, the final model with a time window within the last 7 days had the smallest prediction error, and the prediction accuracy was as high as 98.7%, 90.9%, and 81.6% for the next 3, 7, and 14 days, respectively. Among Charleston, Greenville, Horry, Spartanburg, and Richland counties, the best predictive models were established based on their observations in the last 9, 14, 28, 20, and 9 days, respectively. The 14-day prediction accuracy ranged from 60.3%-74.5%. CONCLUSIONS: Using Twitter-based population mobility data could provide acceptable predictions of COVID-19 daily new cases at both the state and county level in South Carolina. Population mobility measured via social media data could inform proactive measures and resource relocations to curb disease outbreaks and their negative influences.

Gradient radiation breeding and culture domestication of menaquinone producing strains.

By comparing the survival rate and positive mutation rate of the primary mutagenic strain and progeny mutagenic strain under different radiation doses, the results showed that the tolerance of the mutagenic strain to radiation dose increased with the increase of the mutagenic generations. We adopted an improved gradient radiation breeding strategy to improve the breeding efficiency. The strains were treated with radiation in four stages. The first stage was low energy N+ ion implantation (ion energy 15 keV, dose 80 × 2.6 × 1013 cm-2). In the second stage, the energy and dose of N+ ion reached to 20 keV, 90 × 2.6 × 1013 cm-2. In the third stage, 60Co-γ radiation (dose of 1.56 kGy) was used. In the fourth stage, the radiation dose of 60Co-γ increased to 1.82 kGy. After each stage of radiation, the MK (Menaquinone) precursor 1, 4-dihydroxy-2-naphthalate (DHNA) was used as the stress factor to domesticate the mutant strains. By gradually increasing the concentration of DHNA in the culture medium, the substrate tolerance of Flavobacterium sp. was effectively improved. By measuring SOD (superoxide dismutase) activity and malondialdehyde, it showed that the cell damage caused by radiation mutagenesis to the offspring mutant was less than that of the primary mutant. Changes in membrane permeability and membrane potential of the mutant strains were reflected in changes in fluorescence intensity of luciferin diacetate and rhodamine 123, which could explain the enhanced substrate tolerance of strain F-2. After gradient radiation breeding and culture acclimation, the biomass of mutant Strain F-2 was 6.59 g/L, and the MK yield was 9.59 mg/L.