Navigating flower development with a new atlas

In this issue of Developmental Cell, a study presents a 4D atlas integrating live imaging data and expression patterns of 28 regulatory genes in early flower development, which can be used to test gene regulation networks, leading to new hypotheses about the interactions and growth control activities of regulatory genes.

[Clinical analysis of 11 cases of sub-acute arsenic poisoning]

Objective: To investigate the clinical manifestations, treatments and prognosis of subacute arsenic poisoning. Methods: In January 2020, a retrospective analysis was carried out on 11 patients hospitalized with subacute arsenic poisoning caused by arsenic contaminated drinking water. We observed manifestations, treatments and prognosis. Results: The main clinical presentations of subacute arsenic poisoningin were gastroenteritis in early phase, some of them had other organ damage, such as skin, blood, liver, kidney, cardiovascular and so on. The later phase was mainly peripheral nervous system damage. The treatment was mainly to chelate arsenic, protect target organs and treat toxic peripheral neuropathy. Most were significantly recoveried, but the recovery of severe toxic peripheral neuropathy was tardy. Conclusion: Acute gastroenteritis is the mainly early manifestation of subacute arsenic poisoning caused by digestive tract, and toxic peripheral neuropathy in the later phase. The prognosis is good, but the recovery of severe toxic peripheral neuropathy is tardy.

Primary Cell Wall Modifying Proteins Regulate Wall Mechanics to Steer Plant Morphogenesis

Plant morphogenesis involves multiple biochemical and physical processes inside the cell wall. With the continuous progress in biomechanics field, extensive studies have elucidated that mechanical forces may be the most direct physical signals that control the morphology of cells and organs. The extensibility of the cell wall is the main restrictive parameter of cell expansion. The control of cell wall mechanical properties largely determines plant cell morphogenesis. Here, we summarize how cell wall modifying proteins modulate the mechanical properties of cell walls and consequently influence plant morphogenesis.

Phthalyl starch nanoparticles as prebiotics enhanced nisin production in Lactococcus lactis through the induction of mild stress in probiotics

AIM OF THE STUDY

Effect of internalized phthalyl starch nanoparticles (PSNs) on the antimicrobial ability of Lactococcus lactis (LL) KCTC 2013.

METHODS AND RESULTS

Phthalyl starch nanoparticles were prepared by self-assembly of phthalyl starch and the amount of the hydrophobic phthalic moieties were characterized by nuclear magnetic resonance: PSN1 (DS: 14·3 mol.%), PSN2 (DS: 17·8 mol.%) and PSN3 (DS: 30·4 mol.%). The sizes of PSN1, PSN2 and PSN3 measured by dynamic light scattering were 364·7, 248·4 and 213·4 nm, respectively, and the surface charges of PSNs measured by electrophoretic light scattering were negative charges and PSNs were spherical in shape according to scanning electron microscope. It was found that when PSNs were treated with LL, the PSNs were internalized into LL through nanoparticle size-, energy- and glucose transporter-dependent mechanisms. The internalization was confirmed by confocal laser scanning microscopy and fluorescence-activated cell sorting. Nisin was isolated and identified by sodium dodecyl sulphate-polyacrylamide gel electrophoresis. Also, more nisin was produced from PSNs-treated LL than untreated- or starch-treated LL. Co-culture assay and agar diffusion test were performed to test the antimicrobial ability. Antimicrobial ability against Gram-negative Escherichia coli k88, Salmonella gallinarum and Gram-positive Listeria monocytogenes of LL treated with PSNs was higher than that of untreated or starch-treated group. Finally, it was found that the expression level of stress response genes dnaK, dnaJ and groES was significantly higher in PSNs-treated groups compared with starch-treated group or LL alone.

CONCLUSION

The internalization of PSNs into LL enhanced the production of nisin through mild intracellular stimulation, resulting in enhanced antimicrobial ability.

SIGNIFICANCE AND IMPACT OF THE STUDY

This study shows the promising potential of PSNs as new prebiotics for increasing the production of nisin, thus demonstrating a new method for the biological production of such antimicrobial peptides.

Childhood COVID-19: a multicentre retrospective study

Objectives

To investigate the clinical and epidemiological characteristics of paediatric patients with coronavirus disease-19 (COVID-19).

Methods

Paediatric patients diagnosed with COVID-19 between January 15 and March 15, 2020, from seven hospitals in Zhejiang Province, China, were collected retrospectively and analysed.

Results

Thirty-two children with COVID-19, ranging in age from 3 months to 18 years, were enrolled. Family aggregation occurred in 87.5% of infant and preschool-aged children (7/8), and also school-aged children (14/16), but in only 12.5% (1/8) of adolescents (p < 0.05, p < 0.001). Most of these patients had mild symptoms: mainly fever (20/32) followed by cough (10/32) and fatigue (4/32). The average durations of viral RNA in respiratory samples and gastrointestinal samples were 15.8 d and 28.9 d, respectively. Detox duration in faeces decreased with age: 39.8 d, 27.5 d and 20.4 d in infants and preschool children, school children, and adolescents respectively (p_{0–6, –18} <0.01, p_{0–6, –14} <0.05). Pneumonia was found in 14 children, but there was no statistical significance in the incidence of pneumonia between different age groups. Thirty patients were treated with antiviral drugs, and all patients were stable and gradually improved after admission.

Conclusions

Most children with COVID-19 had a mild process and a good prognosis. More attention should be paid to investigation of household contact history in the diagnosis of COVID-19 in young children. Viral RNA lasts longer in the gastrointestinal system than in the respiratory tract, especially in younger children.

Viral kinetics and factors associated with rapid viral clearance during lopinavir/ritonavir-based combination therapy in non-severe COVID-19 patients

OBJECTIVE

Lopinavir/ritonavir has modest antiviral activity against severe acute respiratory syndrome coronavirus 2. The aim was to investigate the viral kinetics and factors associated with viral clearance during lopinavir/ritonavir-based combination treatment in non-severe patients.

PATIENTS AND METHODS

Sixty-four patients were retrospectively enrolled. Viral RNA was detected by real-time RT-PCR assay from sputum or throat swab samples at different time points. The patterns of viral kinetics were characterized, and factors associated with rapid viral clearance, which was defined as viral RNA undetectable within two weeks, were analyzed using multivariate logistic regression analyses.

RESULTS

All patients achieved viral RNA negativity and were discharged from the hospital. Furthermore, 48 (75%) and 16 (25%) patients achieved rapid and delayed viral clearance, respectively. The lymphocyte counts of rapid viral clearance patients (1.40 [1.20-1.80] × 109/L) were higher, when compared to delayed viral clearance patients (1.00 [0.70-1.47] × 109/L) (p=0.024). The multivariate logistic analysis revealed that high lymphocyte count (≥1.3×109/L) is an independent factor associated with rapid viral clearance (OR=7.62, 95% CI=1.15-50.34, p=0.035).

CONCLUSIONS

The viral shedding exhibited different patterns during treatment. Immune insufficiency is responsible for the delayed viral clearance, suggesting that an immunomodulator should be considered to promote viral clearance in patients with low lymphocyte counts.

Robust organ size requires robust timing of initiation orchestrated by focused auxin and cytokinin signalling

Organ size and shape are precisely regulated to ensure proper function. The four sepals in each Arabidopsis thaliana flower must maintain the same size throughout their growth to continuously enclose and protect the developing bud. Here we show that DEVELOPMENT RELATED MYB-LIKE 1 (DRMY1) is required for both timing of organ initiation and proper growth, leading to robust sepal size in Arabidopsis. Within each drmy1 flower, the initiation of some sepals is variably delayed. Late-initiating sepals in drmy1 mutants remain smaller throughout development, resulting in variability in sepal size. DRMY1 focuses the spatiotemporal signalling patterns of the plant hormones auxin and cytokinin, which jointly control the timing of sepal initiation. Our findings demonstrate that timing of organ initiation, together with growth and maturation, contribute to robust organ size.

Correlation between MRAS gene polymorphism and atherosclerosis

OBJECTIVE

The aim of this study was to explore the correlation between muscle RAS oncogene homolog (MRAS) gene polymorphism and the onset risk of atherosclerosis (AS).

PATIENTS AND METHODS

A total of 135 AS patients diagnosed and treated in our hospital from November 2017 to October 2018 were randomly enrolled in the observation group. Meanwhile, 150 healthy adults were selected as control group. Venous blood was withdrawn from all the subjects, and DNAs were extracted. MRAS gene loci rs9818870 and rs3755751 were analyzed by the multiplex SNaPshot method, and their correlations with the onset risk of AS were explored.

RESULTS

No statistically significant differences in the frequencies at gene loci were observed between the two groups (p>0.05). Subjects with genotype TT at rs9818870 exhibited significantly higher risk of AS (p=0.041<0.05). The recessive model of rs9818870 (GG + AG/AA) in AS patients with coronary heart disease was correlated with AS (p=0.048<0.05). Similarly, the dominant model of rs3755751 (TT/TC+CC) in those with hypertension was associated with AS (p=0.027<0.05).

CONCLUSIONS

MRAS gene is correlated with the onset of AS to a certain degree.

Clinical efficacy of lopinavir/ritonavir in the treatment of Coronavirus disease 2019

OBJECTIVE

The Coronavirus disease 2019 (COVID-19) which outbroke in December 2019 is highly contagious with a low cure rate. In view of this, there is an urgent need to find a more appropriate therapeutic scheme against COVID-19. The study aimed to investigate whether lopinavir/ritonavir (LPV/r) in combination with other pneumonia-associated adjuvant drugs has a better therapeutic effect on COVID-19.

PATIENTS AND METHODS

Totally 47 patients with COVID-19 infection who were admitted to Rui'an People's Hospital between January 22 and January 29, 2020 were collected. The patients were divided into the test group and the control group according to whether they had been treated with LPV/r or not during hospitalization. Patients in the test group were treated with LPV/r combined with adjuvant medicine, while those in the control group were just treated with adjuvant medicine. The changes of body temperature, blood routine and blood biochemistry between the two groups were observed and compared.

RESULTS

Both groups achieved good therapeutic effect with the body temperature of patients decreased gradually from admission to the 10th day of treatment. But the body temperature of patients in the test group decreased faster than that of the control group. Blood routine indexes showed that compared with the control group, the abnormal proportion of white blood cells, lymphocytes and C-reactive protein of the test group could be reduced to some extent. Blood biochemical indexes exhibited that the proportion of patients with abnormal alanine aminotransferase and aspartate aminotransferase in the test group were lower than the control group. The number of days for nCoV-RNA turning negative after treatment was significantly decreased in the test group than that in the control group.

CONCLUSIONS

Compared with the treatment of pneumonia-associated adjuvant drugs alone, the combination treatment with LPV/r and adjuvant drugs has a more evident therapeutic effect in lowering the body temperature and restoring normal physiological mechanisms with no evident toxic and side effects. In view of these conclusions, we suggested that the use of LPV/r combined with pneumonia-associated adjuvant drugs in the clinical treatment for patients with COVID-19 should be promoted.

Mesoporous TiO2/carbon catalytic ozonation for degradation of p-chloronitrobenzene

In this study, a mesoporous TiO₂/carbon catalyst (TiO₂/C) was prepared by a facile impregnation-carbonization approach to catalyze ozonation of p-chloronitrobenzene (p-CNB). The catalyst was well characterized and the catalytic efficiency under various conditions was systematically evaluated. TiO₂/C has a disordered mesostructure with a high specific surface area. 92.8% of p-CNB (2 μmol/L) can be degraded within 20 min in the TiO₂/C/O₃ system in the presence of 1 mg/L O₃, 100 mg/L catalyst, at pH = 5. Based on the evaluation of the effect of basic parameters, it could be deduced that the removal of p-CNB relied on the synthetic effect of catalysis by TiO₂/C and the autocatalytic induction of p-CNB. The removal efficiency of p-CNB, the structure change and the leaching of Ti ions were also evaluated in five cycles, indicating TiO₂/C is stable and recyclable for catalytic ozonation in water treatment.

Crystallization-induced refractive index modulation on sapphire-derived fiber for ultrahigh temperature sensing

We have demonstrated crystallization-induced refractive index (RI) modulation on sapphire-derived fiber (SDF) showing superheat resistance and developed the SDF based Fabry-Perot interferometers (FPIs) for ultrahigh temperature sensing. The SDF is a special fiber with high concentration of alumina to silica in the fiber core region. Reheating and cooling the SDF by arc discharge generates mullite particles in the core region, which achieves RI modulation up to ~0.015. Such crystallized region in the SDF is explored as mirrors for FPI, showing a good linear response to temperature with sensitivity of ~13.2 pm/°C. Benefiting from superheat resistance of the crystallized SDF being mirrors, the developed SDF-FPI sensor is capable to withstand high temperature up to 1600°C, which is the highest working temperature for amorphous fiber. Moreover, the SDF-FPI sensor exhibits 6-hour stability at 1200°C. The crystallized SDF-FPIs with compactness, wide temperature working range, high sensitivity, and robustness show great potential application in harsh environment such as turbine engines, power plants, petrochemical, gas industry, etc.