Geraniol-a potential alternative to antibiotics for bovine mastitis treatment without disturbing the host microbial community or causing drug residues and resistance

Mastitis is one of the most prevalent diseases of dairy cows. Currently, mastitis treatment in dairy cows is mainly based on antibiotics. However, the use of antibiotics causes adverse effects, including drug resistance, drug residues, host-microbiome destruction, and environmental pollution. The present study sought to investigate the potentiality of geraniol as an alternative to antibiotics for bovine mastitis treatment in dairy cows. Additionally, the effectiveness of treatment, improvement in inflammatory factors, the influence on microbiome, presence of drug residues, and drug resistance induction were compared and analyzed comprehensively.Geraniol showed an equivalent therapeutic rate as antibiotics in the mouse infection model and cows with mastitis. Moreover, geraniol significantly inhibited the pathogenic bacteria and restored the microbial community while increasing the abundance of probiotics in milk. Notably, geraniol did not destroy the gut microbial communities in cows and mice, whereas antibiotics significantly reduced the diversity and destroyed the gut microbial community structure. Additionally, no geraniol residue was detected in milk four days after treatment discontinuation, but, antibiotic residues were detected in milk at the 7th day after drug withdrawal. In vitro experiments revealed that geraniol did not induce drug resistance in the Escherichia coli strain ATCC25922 and Staphylococcus aureus strain ATCC25923 after 150 generations of culturing, while antibiotics induced resistance after 10 generations. These results suggest that geraniol has antibacterial and anti-inflammatory effects similar to antibiotics without affecting the host-microbial community structure or causing drug residues and resistance. Therefore, geraniol can be a potential substitute for antibiotics to treat mastitis or other infectious diseases and be widely used in the dairy industry.

Genome Sequencing of Amomum tsao-ko Provides Novel Insight Into Its Volatile Component Biosynthesis

As an important economic and medicinal crop, Amomum tsao-ko is rich in volatile oils and widely used in food additives, essential oils, and traditional Chinese medicine. However, the lack of the genome remains a limiting factor for understanding its medicinal properties at the molecular level. Here, based on 288.72 Gb of PacBio long reads and 105.45 Gb of Illumina paired-end short reads, we assembled a draft genome for A. tsao-ko (2.70 Gb in size, contig N50 of 2.45 Mb). Approximately 90.07% of the predicted genes were annotated in public databases. Based on comparative genomic analysis, genes involved in secondary metabolite biosynthesis, flavonoid metabolism, and terpenoid biosynthesis showed significant expansion. Notably, the DXS, GGPPS, and CYP450 genes, which participate in rate-limiting steps for terpenoid backbone biosynthesis and modification, may form the genetic basis for essential oil formation in A. tsao-ko. The assembled A. tsao-ko draft genome provides a valuable genetic resource for understanding the unique features of this plant and for further evolutionary and agronomic studies of Zingiberaceae species.

Epidemiological and clinical characteristics of patients with COVID-19 from a designated hospital in Hangzhou City: a retrospective observational study

INTRODUCTION

The outbreak of coronavirus disease 2019 (COVID-19) has exerted a heavy burden on public health worldwide. We aimed to investigate the epidemiological and clinical characteristics of patients with COVID-19 in a designated hospital in Hangzhou, China.

METHODS

This was a retrospective study that included laboratory-confirmed cases of COVID-19 in XiXi Hospital of Hangzhou from 15 January 2020 to 30 March 2020. We reviewed and analysed the epidemiological, demographic, clinical, radiological, and laboratory features involving these cases. Age-tratification analysis was also implemented.

RESULTS

We analysed 96 confirmed cases. The patients had a mean age of 43 years, with six patients younger than 18 years and 14 patients older than 60 years. No significant gender difference was discovered. Co-morbidities were commonly observed in patients aged over 40 years. Twenty eight of the patients had travelled from Wuhan City, and 51 patients were infected through close contact. Familial clusters accounted for 48 of the cases. The mean incubation time was 7 days, and the symptoms were mainly fever, cough, fatigue, and sore throat. Lymphocytopenia was observed predominantly in patients aged over 60 years. Fifty five patients presented with bilateral pulmonary lesions. The radiological changes were typically distributed in the subpleural area, and pleural effusion rarely occurred. All patients were discharged successfully.

CONCLUSION

During the early stage of the COVID-19 outbreak, half of the patients from a designated hospital in Hangzhou City were discovered as familial clusters. Therefore, strict prevention and control measures during self-isolation should be implemented. Patients aged over 60 years who had underlying co-morbidities were prone to lymphocytopenia and severe infection.

Transcatheter aortic valve replacement in atypical valve anatomy using the Lotus valve : A Chinese single-center experience

BACKGROUND

In the West, the safety and efficacy of the Lotus valve have been demonstrated; however, data in the Chinese population are still lacking. Few studies have compared the clinical outcomes of transcatheter aortic valve replacement (TAVR) with the Lotus valve in patients with bicuspid or tricuspid aortic valve stenosis. Our aim was to assess TAVR outcomes with the Lotus aortic valve in a Chinese patient cohort.

METHODS

In total, 23 symptomatic, high-surgical risk patients with severe aortic valve stenosis were enrolled. Among them, nine patients (39%) had bicuspid aortic valves, and three patients had a large annulus dimension. The Lotus valve was successfully implanted in all patients. To facilitate accurate positioning, partial re-sheathing was attempted in ten patients (43.5%), while one patient had a full retrieval. One-year clinical follow-up was completed in all patients.

RESULTS

There were no deaths, strokes, or major adverse cardiac and cerebrovascular events in 22 of the 23 patients at 30 days; the all-cause mortality rate at 1 year was 4.4% (1 of 23 patients). The mean aortic valve gradient decreased from 51.5 ± 8.8 mm Hg at baseline to 13.4 ± 4.9 mm Hg (p < 0.001) and the valve area increased from 0.6 ± 0.2 cm² to 1.5 ± 0.4 cm² (p < 0.001) at 30 days. Paravalvular leakage was absent or mild (22%), and no patient had severe paravalvular leakage. Six patients (26.1%) required a postprocedural pacemaker. There was no difference regarding the procedural and the 1‑year outcomes between patients with bicuspid and tricuspid aortic valve stenosis.

CONCLUSION

Our single-center experience demonstrated that the Lotus valve is feasible and effective for Chinese patients with aortic valve stenosis, including atypical cases with bicuspid aortic valves or large aortic annulus size.

Prevalence and natural course of occult hepatitis B virus infection in residents of 2 communities of Wuwei City, Gansu Province, China

Occult hepatitis B infection (OBI) is characterized by serum hepatitis B surface antigen (HBsAg) negative and hepatitis B virus (HBV) DNA positive (HBsAg-/HBV DNA+). Occult hepatitis B infection in community-based populations has been scarcely investigated, and OBI outcomes remain unclear, especially in Wuwei, a region located in Northwest China. This region is one of the areas in China that has the highest prevalence of chronic HBV infection. A prospective study was performed in the general population of 2 towns of Wuwei from June 2011 to May 2014. A questionnaire was used to collect demographic and medical data, and serum samples were collected from the participants and stored until analysis. DNA was detected using quantitative PCR (qPCR) or nested PCR, the HBV DNA from HBV DNA-positive or possible positive (below the detection limit) subjects was extracted and amplified by nested PCR, and the PCR products were sequenced. Sequence analysis was performed using the Mega 6.0 program and CLC sequence viewer software. Hepatitis B virus DNA was detected in 90 of 3,080 HBsAg-negative subjects, and the prevalence of OBI in the study population was 2.92% (90/3,080, 95% CI: 2.33%-3.51%). Hepatitis B virus genomes in 51 of 80 objects (63.75%) contained mutations in the "a" determinant of HBsAg. After 2 years follow-up, 42 of 90 HBV DNA of OBI subjects remained positive, and the natural clearance rate of OBI subjects was 53.3%. Occult hepatitis B infection prevalence in this cohort was much lower than chronic HBV infection in the same region. HBV DNA was cleared in most OBI subjects during the 2 year period. Our data suggest that some OBI may represent a late stage of resolving the HBV infection process.

Overt and occult hepatitis B virus infection among community children in Northwest China

Although a universal newborn hepatitis B (HB) immunization programme has been implemented in China, hepatitis B virus (HBV) breakthrough infection, including HB surface antigen (HBsAg)-positive infection and occult HBV infection (OBI), still occurs during infancy or childhood. Obtaining the actual prevalence of HBV infection in general children is important for preventing and controlling the spread of HB. Accordingly, we investigated the prevalence of overt infection and OBI in community children and compared the serological and virological characteristics of OBI and HBsAg carrier children to clarify the mechanisms related to OBI. In total, 6 706 community children <12 years of age were included from a population-based HBV seroepidemiological investigation in Northwest China. The HBsAg carrier rate in community children was 1.60% (107/6706), and the anti-HBs positive rate was 57.35% (3846/6706). Additionally, 1192 HBsAg-negative children were examined for OBI using nested PCR. The prevalence of OBI in local children was 1.26% (15/1192), and the predominant OBI genotypes were C and D. The 15 OBI children and 29 HBsAg-positive children from the same population did not have a statistical significant difference in age, gender, alanine aminotransferase (ALT), proportion of anti-HBs or anti-HBc, viral genotypes or mutations. Children with chronic overt infection had higher viral loads than OBI children (P=.004). These results suggested that HBV overt and occult infection of children was more serious in underdeveloped north-west regions. HBV neonatal immunization and catch-up programmes should be strengthened and supplemented. None of specific viral mutations or genotypes related to OBI were found. OBI may be a specific stage of HBV infection.

Epidemiological characteristics of the carriers with coexistence of HBsAg and anti-HBs based on a community cohort study

The coexistence of HBsAg and anti-HBs is an atypical serological pattern in HBV infection. There is no epidemiological characteristics of this serological pattern in the community and there is controversy over the molecular mechanisms underlying this pattern. We investigated the epidemiological characteristics of the carriers with HBsAg and anti-HBs in a longitudinal community cohort study. The prevalence of this atypical serological pattern was 2.93% (122/4169) in HBsAg-positive populations. The prevalence progressively increased with age from 40 to 70 years old. The rate of HBeAg positive and detectable HBV DNA were both significantly higher in carriers with this pattern than in carriers who were HBsAg positive but anti-HBs negative (26/122 verse 598/4047, P = 0.046; 86/122 verse 275/529,P < 0.001). After 1 year of follow-up, 85.19% of the carriers still had coexistence HBsAg and anti-HBs, 14.81% of the carriers lost their anti-HBs. Viral sequencing showed that carriers with coexistence of HBsAg and anti-HBs had higher numbers of residue changes within the S gene than carriers who were HBsAg positive but anti-HBs negative (2.42 verse 1.33 changes per 100 residues, P < 0.05). Hence, the coexistence of HBsAg and anti-HBs is a unique serological pattern which may be associated with an increased risk of adverse clinical outcome and may be related to HBsAg immune variants which have genotypic heterogeneity.

Ultrafast-laser-induced backward stimulated Raman scattering for tracing atmospheric gases

By combining tunable broadband pulse generation with the technique of nonlinear spectral compression we demonstrate a prototype scheme for highly selective detection of air molecules by backward stimulated Raman scattering. The experimental results allow to extrapolate the laser parameters required for standoff sensing based on the recently demonstrated backward atmospheric lasing.

Extended magnetic reconnection across the dayside magnetopause

The extent of where magnetic reconnection (MR), the dominant process responsible for energy and plasma transport into the magnetosphere, operates across Earth's dayside magnetopause has previously been only indirectly shown by observations. We report the first direct evidence of X-line structure resulting from the operation of MR at each of two widely separated locations along the tilted, subsolar line of maximum current on Earth's magnetopause, confirming the operation of MR at two or more sites across the extended region where MR is expected to occur. The evidence results from in-situ observations of the associated ion and electron plasma distributions, present within each magnetic X-line structure, taken by two spacecraft passing through the active MR regions simultaneously.

Reconnection at high latitudes: antiparallel merging

New investigations have renewed the debate on the occurrence of magnetic reconnection of Earth's dayside magnetopause. Here, we show for the first time strong evidence for a high-latitude reconnection site, located on initially closed field lines, where the magnetic field orientations inside and outside the magnetopause are close to antiparallel. The evidence centers on repeated sampling of the ion diffusion region and associated null magnetic field by four spacecraft in formation, together with simultaneous monitoring of the local magnetosheath behavior by a fifth spacecraft.

Glucocorticoid receptor activation selectively hampers N-methyl-d-aspartate receptor dependent hippocampal synaptic plasticity in vitro

Corticosterone and exposure to stressful experiences have been reported to decrease hippocampal synaptic plasticity, in particular when relatively mild stimulation paradigms-presumably activating predominantly N-methyl-d-aspartate receptors-are being used. Using various stimulation paradigms and pharmacological approaches we tested therefore the hypothesis that elevated corticosterone levels, by activating glucocorticoid receptors, predominantly hamper N-methyl-D-aspartate receptor dependent synaptic plasticity in vitro. To address this, mouse hippocampal slices were treated for 20 min with corticosterone (100 nM) or vehicle and synaptic efficacy was examined 1-6 h later. First, we found that primed burst potentiation and synaptic potentiation after 10 Hz stimulation are predominantly N-methyl-D-aspartate receptor dependent, and are significantly suppressed after corticosterone treatment. Second, these latter effects were prevented by treating slices with the glucocorticoid receptor antagonist mifepristone prior to and during corticosterone administration. Third, theta burst potentiation, which was shown to involve activation of both N-methyl-D-aspartate receptors, voltage-dependent calcium channels and possibly other mechanisms, was not affected by corticosterone. However, theta-burst potentiation in the presence of nifedipine-singling out primarily the N-methyl-D-aspartate receptor dependent component-was reduced by corticosterone. These results indicate that corticosterone, via glucocorticoid receptor activation, selectively hampers N-methyl-D-aspartate receptor dependent synaptic plasticity in vitro and leaves more complex forms of long term potentiation unaffected. We speculate that these effects are involved in the impairment of cognitive performance by corticosteroid hormones after exposure to stressful and traumatic experiences.

Structural studies of the glycopeptides of B-chain of cinnamomin--a type II ribosome-inactivating protein by nuclear magnetic resonance

Cinnamomin is a plant type II ribosome-inactivating protein (RIP) isolated from the seeds of Cinnamomum camphora. It consists of two nonidentical polypeptide chains (A- and B-chain) held together through one disulfide linkage. Its A- and B-chain contain 0.3% and 3.9% sugars respectively. The B-chain of cinnamomin was digested by pronase E and then the liberated glycopeptides were separated from non-glycopeptides by gel filtration chromatography on a Bio-Gel P-4 column. Three crude glycopeptides were obtained by continuing chromatography over anion-exchange resin (AG1-X2) in the buffer of 2% pyridine-acetic acid (pH 8.3) with a polygradient elution system. Through further purification by the gel filtration chromatography and HPLC, three major glycopeptides, GP1, GP2 and GP3 were obtained. Mainly by two-dimensional Nuclear Magnetic Resonance (NMR) including TOCSY, DQF-COSY, NOESY, HMQC and HMBC, their primary structures were analyzed as: Man\balpha1,3Man\balpha1,6(Man\balpha1,3)(Xyl\bbeta1,2)Man\bbeta1,4GlcNAc\bbeta1,4GlcNAc\bbeta1-(Gly-)Asn-Asn-Thr(GP1), Man\balpha1,6(Man\balpha1,3)(Xyl\bbeta1,2)Man\bbeta1,4GlcNAc\bbeta1,4(Fuc\balpha1,3)GlcNAc\bbeta1-Asn-Ala-Thr(GP2),Man\balpha1,6(Man\balpha1,3)Man\balpha1,6(Man\balpha 1,2 Man\balpha1,3)Man\bbeta1,4GlcNAc\bbeta1,4GlcNAc\bbeta1-(Ala-)Asn-Gly-Thr(GP3).

Ribotoxins and their applications in probing the topographical structure of ribosomes

Ribotoxins are a group of ribosome-inactivating proteins (RIPs) isolated mostly from plants. They inactivate ribosomes by a mechanism as RNA N-glycosidase that removes a specific adenine base from the highly conserved "S/R domain" in the largest ribosomal RNA. In this review, we introduce the major results from our laboratory in recent years on the study of the structure and function of RIPs and ribosomes: [1] Purification and characterization of the enzymatic mechanism of RIPs. Several new RIPs were purified and their RNA N-glycosidase and supercoil-dependent DNA endonuclease activities were studied. [2] The topographical structure of ribosomes. The relationship between the structure and function of ribosomes, especially of the "S/R domain" in rat 28S rRNA, were investigated by means of RIPs and other chemical probes. [3] The cytotoxicity of two RIPs to carcinoma cells. [4] Several new methods for studying RIPs and probing the structure of ribosomes were developed, i.e., radioassays for RNA N-glycosidase, glycoprotein detection by fluorescent labeling on SDS-polyacrylamide gels, and methods for small RNA sequencing.

Purification and characterization of trichomaglin--a novel ribosome-inactivating protein with abortifacient activity

Trichomaglin, a novel ribosome-inactivating protein, has been isolated from root tuber of a plant Maganlin (Trichosanthes Lepiniate, Cucurbitaceae). The isolation and purification procedure included ammonium sulfate precipitation, Sephadex G-75 chromatography and CM-Sephadex C-50 chromatography. The protein was identified to be homogeneous by SDS-PAGE and FPLC analysis. Its molecular weight is 24,673 dalton and isoelectric point is 5.8, determined by electrospray ionization mass spectroscopy and isoelectric focusing gel electrophoresis respectively. Trichomaglin can inhibit protein synthesis in rabbit reticulocyte lysate with ID50 of 10.1 nM. When rat ribosome was incubated with trichomaglin, a diagnostic RNA fragment appeared on polyacrylamide gel after ribosomal RNAs were treated with acidic aniline. It was concluded that trichomaglin is an RNA N-glycosidase. In addition, it has been verified to be an abortifacient protein.

Purification and activity study of the A- and B-chains of cinnamomin, a type II ribosome-inactivating protein

The strong hydrophobic interaction between the A- and B-chains of cinnamomin, a type II ribosome-inactivating protein, makes it difficult to separate A- and B-chains after the disulfide bond is broken. We failed to separate the A-chain from B-chain of cinnamomin using methods under usual conditions. A convenient method for purification of the A- and B-chains of cinnamomin on a large scale has been developed. We chose urea to weaken the non-covalent interaction between the A- and B-chains. In the presence of 4M urea, the A- and B-chains of the reduced cinnamomin are separated effectively by DEAE-cellulose chromatography. The purified A-chain still displays the RNA N-glycosidase activity and the B-chain loses the lectin activity. After refolding in vitro in the presence of lactose, the B-chain is renatured and the active B-chain with lectin activity can be further purified by Sepharose 4B affinity chromatography. From 80 mg of cinnamomin, 10 mg of A-chain (25%) and 38 mg of the B-chain (95%) were obtained. In addition, the intrinsic fluorescence spectra of the A- and B-chains were employed to study the structural changes in the active and the non-active forms of cinnamomin A- and B-chains.

[Scanning electron microscope observation and image quantitative analysis of Hippocampi]

The "scale-like projects" on the derma of 3 species of Hippocampi, H. kuda Bleerer, H. trimaculatus Leach and H. japonicus Kaup were observed by scanning electron microscope (SEM). Results showed that some characteristics such us size, shape and type of arrangement of the "scale-like projects" can be considered as the evidence for microanalysis. Image quantitative analysis of the "scale-like project" was carried out on 45 pieces of photograph using area, long diameter, short diameter and shape factor as parameters. No difference among the different parts of the same species was observed, but significant differences were found among the above 3 species.

[The SEM observation of the medicinal materials "hailong"]

The SEM observation of the medicinal meterials "Hailong" have been carried out. The results showed there are significantly difference among 7 species "Hailong".

Characterization of the enzymatic mechanism of gamma-momorcharin, a novel ribosome-inactivating protein with lower molecular weight of 11,500 purified from the seeds of bitter gourd (Momordica charantia)

The enzymatic mechanism of a small ribosome-inactivating protein, gamma-momorcharin, purified from the seeds of Momordica charantia, has been characterized. By SDS-polyacrylamide and electrospray ionization mass spectrometry, its molecular weight was measured to be 11,500 daltons which is much lower than other RIPs known to date. It can inhibit the protein synthesis in the rabbit reticulocyte cell-free system with ID50 of 55 nM. When rat liver ribosome was incubated with gamma-momorcharin, a diagnostic RNA fragment appeared on the gel after rRNAs were treated with acid aniline. Sequencing of the RNA fragment indicates that the action site of gamma-momorcharin in 28S ribosomal RNA of rat liver is at a specific adenosine (position 4324), which is in a highly conserved loop of 28S rRNA.

[Effect of tetramethyl pyrazine on coronary vasoconstriction induced by endothelin-1 in dogs]

The purpose of this study was to determine the antagonistic effect of tetramethyl pyrazine (TMP), a sort of chinese herbal medicine, on coronary vasoconstriction induced by endothelin-1 (ET-1) in closed chest dogs. ET-1 at doses of 50, 75 and 100 pmol was selectively administered into left main coronary artery and coronary angiogram was performed in 1, 3 and 10 minutes after intracoronary administration of ET-1. After a 60 minute interval ET-1 administration and coronary angiogram were repeated in two groups in group A with 5 dogs intravenous infusion of saline solution was administered while in group B with 4 dogs TMP was infused at a dose of 80 mg/kg. Blood pressure of intra-femoral artery, heart rate and ECG were monitored during the experiment. The study demonstrated that coronary vessel diameter significantly decreased by 17% (P < 0.02) in group A and 20% (P < 0.02) in group B, associated with ischemia in ECG (4/5 in group A and 3/4 in group B) after intracoronary administration of ET-1. Endothelin-1 induced coronary vasoconstriction and ischemic changes in ECG were significantly inhibited by intravenous TMP. The coronary diameter increased by 20% (P < 0.03) after administration of TMP, comparing with the control group. Heart rate had an increased response to TMP. In conclusion this study demonstrated that intracoronary administration of ET-1 caused significant myocardial ischemia through coronary vasoconstriction, which was inhibited by TMP. TMP significantly dilated coronary artery.

Stimulation of thymidine kinase activity in baculovirus infected cells is not due to a virus-coded enzyme

A polyhedrin-positive recombinant autographa californica nuclear polyhedrosis virus (AcNPV) carrying a herpes simplex virus thymidine kinase gene under the control of the SynXIV promoter, a fusion of synthetic and linker-modified polyhedrin promoters, has been constructed. When this recombinant baculovirus was used to infect a variant of Spodoptera frugiperda cells deficient in thymidine kinase (TK-), a high level of TK activity was detected. These results, in conjunction with the demonstration that AcNPV could replicate in TK- S. frugiperda cells and no TK activity was found throughout infection, imply that the wild type virus-stimulated TK activity observed in S. frugiperda (TK+) cells is not contributed by a virus-coded enzyme.

Conjunctival immunity: compared effects of ocular or intestinal immunization in rats

The ability to induce a conjunctival antitoxin response by conjunctival or enteric administration of cholera toxin antigen was studied in rats. Repeated enteric immunization caused a vigorous jejunal antitoxin response, but none in the conjunctiva. Enteric immunization did, however, prime for a conjunctival antitoxin response to locally applied antigen, as did direct ocular administration of cholera toxin. Vigorous conjunctival antitoxin responses occurred only after ocular challenge, and were localized to the challenged eye. These results agree with the notions that (1) specific memory cells migrate to the conjunctiva after enteric immunization, or arise locally after ocular immunization; and (2) specific antibody-producing plasma cells arise almost entirely within the immunized conjunctiva, and few if any migrate to the conjunctiva from distant mucosae or from the conjunctiva of the immunized eye to that of the nonimmunized eye.