Extracting a controllable subset from a large-scale dataset so that users can fully understand the entire dataset is a significant topic for multicriteria decision making. In recent years, this ...problem has been widely studied, and various query models have been proposed, such as top-
k
, skyline,
k
-regret and
k
-coverage queries. Among these models, the
k
-coverage query is an ideal query method; this model has stability, scale invariance and high traversal efficiency. However, current methods including
k
-coverage queries cannot deal with deleting some points from the dataset while providing an effective solution set efficiently. In this paper, we study the robustness of
k
-coverage queries in two cases involving the dynamic deletion of data points. The first case is when it is assumed that the whole dataset can be obtained in advance, while the second is when the data points arrive in a stream. For a centralized dataset, we introduce a
sieving
mechanism and use a precalculated threshold to filter a
coreset
from the entire dataset. Then, the
k
-coverage query can be carried out on this small
coreset
instead of the entire dataset, and we propose a threshold-based
k
-coverage query algorithm, which greatly accelerates query processing. For a streaming dataset, a special chain structure is adopted. Furthermore, a single-pass streaming algorithm named Robust-Sieving is proposed. Moreover, the coreset-based method is extended to answer the problem. In addition, sampling techniques are adopted to accelerate query processing under these two circumstances. Extensive experiments verify the effectiveness of our proposed Robust-Sieving algorithm and the coreset-based algorithms with or without sampling.
A novel actinobacterium, strain HNM0039
, was isolated from a marine sponge sample collected at the coast of Wenchang, Hainan, China and its polyphasic taxonomy was studied. The isolate had ...morphological and chemical characteristics consistent with the genus
. Based on the 16S rRNA gene sequence analysis, strain HNM0039
was closely related to
CGMCC 4.7042
(99.38%) and
HNM0071
(99.05%). The organism formed a well-delineated subclade with
CGMCC 4.7042
and
HNM0071
in the
16S rRNA gene tree. Multi-locus sequence analysis (MLSA) based on five house-keeping gene alleles (
D, gyrB, rpoB, recA, trpB) further confirmed their relationship. DNA-DNA relatedness between strain HNM0039
and its closest type strains, namely
CGMCC 4.7042
and
HNM0071
, were 46.5 and 45.1%, respectively. The average nucleotide identity (ANI) between strain HNM0039
and its two neighbor strains were 89.65 and 91.44%, respectively. The complete genome size of strain HNM0039
was 7.2 Mbp, comprising 6226 predicted genes with DNA G+C content of 72.46 mol%. Thirty-one putative secondary metabolite biosynthetic gene clusters were also predicted in the genome of strain HNM0039
. Among them, the tirandamycin biosynthetic gene cluster has been characterized completely. The crude extract of strain HNM0039
exhibited potent antibacterial activity against
in Nile tilapia. And tirandamycins A and B were further identified as the active components with MIC values of 2.52 and 2.55 μg/ml, respectively. Based on genotypic and phenotypic characteristics, it is concluded that strain HNM0039
represents a novel species of the genus
whose name was proposed as
sp. nov. The type strain is HNM0039
(= CCTCC AA 2018045
= KCTC 49236
).
Aim To describe the histopathology and etiology of an outbreak of respiratory disease at a Ptyas mucosus farm in Hainan, China. Methods and results The etiology was confirmed by gross examination and ...microscopic analysis. The bacterial isolates from blood and internal organs were identified by biochemical analysis and 16S rRNA gene sequencing. The virulence and antibiotic resistance characteristics of the isolates were further demonstrated by polymerase chain reaction (PCR), disk diffusion testing, and LD 50 analysis in Kunming mice. Histopathological analysis of the diseased P. mucosus revealed systemic lesions, including severe airway obstruction with large numbers of inflammatory cells and cellulose exudates in the lungs; severe multifocal hepatocyte vacuolar degeneration and necrosis in the liver with excessive inflammatory exudates and chronic granuloma; splenic hemorrhage and partial loss of splenic structure; and renal vascular and interstitial congestion. Providencia rettgeri was isolated from the blood and multiple internal organs (liver, spleen, kidneys, and lungs). All examined isolates (H1, H4, and H13) were multidrug-resistant but sensitive to four antibiotics—cefepime, imipenem, chloramphenicol, and ciprofloxacin. Both H1 and H4 carried five resistance genes bla OXA , tet (A), tet (B), tet (E), and aac (3)-IIa, whereas H13 only carried the tet (A) gene. The dominant virulence pattern of the three isolates was hly A + Zap A + lux S + rsb A. The virulence of H1 strain was tested, and its 50% lethal dose (LD 50 ) in mice was 2.29 × 10 8 CFU ml −1 . Conclusion To our knowledge, this is the first study to describe an outbreak of bacteremia caused by P. rettgeri in farmed rat snakes. Significance and impact of the study The results highlight that P. rettgeri is an emerging bacterial pathogen in farmed reptiles.
Objective
To investigate the preventive effect of hydration combined with reduced glutathione on contrast-induced nephropathy (CIN) after coronary intervention therapy in elderly Chinese patients ...with diabetes.
Methods
Patients with diabetes aged ≥65 years, who received percutaneous coronary intervention (PCI) between 1 August 2016 and 31 December 2018, were enrolled and randomized into two groups: patients treated with hydration combined with reduced glutathione (treatment group) and patients who received hydration alone (controls). Serum creatinine and creatinine clearance levels were measured in all patients before PCI and then daily for 3 days after PCI. Occurrence of CIN (the primary endpoint) was defined as serum creatinine value 25% or 44.2 mmol/l (0.5 mg/dl) above baseline at 72 h after an exposure to contrast medium.
Results
A total of 396 patients were included (treatment group, n = 204; and controls, n = 192). The CIN occurrence rate in the treatment and control group was 5.88% and 6.77%, respectively, with no statistically significant between-group difference.
Conclusion
In elderly patients with diabetes receiving PCI, the risk of CIN was not effectively lowered by hydration combined with reduced glutathione.
Pseudomonas aeruginosa
is a common infectious agent associated with respiratory diseases in boas and pythons, however, the histopathology, resistance and virulence are yet described for this species. ...In this study, we investigated a dying Burmese python rescued from tropical rainforest in Hainan. Clinical signs were open-mouthed breathing, abnormal shedding and anorexia. Abundant yellow mucopurulent secretions were observed in highly ectatic segmental bronchi by postmortem. Histopathological lesions included systemic pneumonia, enteritis, nephritis and carditis.
P. aeruginosa
was the only species isolated from heart blood, kidney, trachea and lung. The phenotype analysis demonstrated that the isolates had strong biofilm, and were sensitive to amikacin, spectinomycin, ciprofloxacin, norfloxacin and polymyxin B, moreover, the LD
50
of the most virulent isolate was 2.22×10
5
cfu/mL in a zebrafish model. Molecular epidemiological analysis revealed that the isolates belonged to sequence type 3495, the common gene patterns were
tox
A +
exo
SYT +
phz
IM +
plc
HN in virulence and
cat
B +
bla
TEM
+
ant
(3'')-I+
tet
A in resistance. This study highlights that
P. aeruginosa
should be worth more attention in wildlife conservation and raise the public awareness for the cross infection and cross spread between animals and human.
Highlights
• Epidermal cells of multiple organs were invaded by Pseudomonas aeruginosa in the wild Burmese python.
• Common gene patterns in the isolates were toxA + exoSYT + phzIM + plcHN for virulence and catB + blaTEM + ant (3'')-I + tetA for resistance.
• Biofilm was necessary for virulence of the isolates infection in a zebrafish model.
We present a 26-year-old woman with ST-segment elevation myocardial infarction in the 14th week of pregnancy. Coronary angiography revealed no abnormalities in the coronary arteries. She had no ...history of coronary risk factors such as smoking, diabetes mellitus, hypertension, or dyslipidemia. Although we do not have direct evidence of coronary spasm in this patient, several factors suggest that coronary spasm is the most likely cause of myocardial infarction. We suspect that hyperthyroidism may have played an important role in coronary spasm in this patient. Early use of coronary angiography is helpful to identify the types of coronary artery lesions.
Essential thrombocythemia (ET) can cause arterial embolism. Patients with arterial thrombosis usually have additional risk factors, such as smoking and hypertension. We report a 70-year-old woman ...with ET who had no risk factors, except for age. Cranial magnetic resonance imaging showed fresh lacunar infarction in several lobes. Electrocardiography showed ST-segment elevation in leads II, III, and aVF. Coronary angioplasty and stenting were successfully performed. We checked the bone marrow and performed genetic testing. The Janus kinase 2 (JAK2) V617F gene mutation was found. This case was a rare initial presentation of previously undiagnosed ET with embolism of cardiovascular and cerebral vessels. Anti-platelet drugs and hydroxyurea were used to prevent further thrombosis in the coronary and cerebral arteries.
Parvoviruses are a diverse group of viruses that are capable of infecting a wide range of animals. In this study, we report the discovery of a novel parvovirus, tilapia parvovirus HMU-HKU, in the ...fecal samples of crocodiles and intestines of tilapia in Hainan Province, China. The novel parvovirus was firstly identified from crocodiles fed with tilapia using next-generation sequencing (NGS). Screening studies revealed that the prevalence of the novel parvovirus in crocodile feces samples fed on tilapia (75-86%) was apparently higher than that in crocodiles fed with chicken (4%). Further studies revealed that the prevalence of the novel parvovirus in tilapia feces samples collected at four areas in Hainan Province was between 40 and 90%. Four stains of the novel parvovirus were identified in this study based on sequence analyses of NS1 and all the four strains were found in tilapia in contrast only two of them were detected in crocodile feces. The nearly full-length genome sequence of the tilapia parvovirus HMU-HKU-1 was determined and showed less than 45.50 and 40.38% amino acid identity with other members of
in NS1 and VP1 genes, respectively. Phylogenetic analysis based on the complete helicase domain amino acid sequences showed that the tilapia parvovirus HMU-HKU-1 formed a relatively independent branch in the newly proposed genus
in the subfamily
according to the ICTV's most recent taxonomic criteria for
classification. Tilapia parvovirus HMU-HKU-1 likely represented a new species within the new genus
. The identification of tilapia parvovirus HMU-HKU provides further insight into the viral and genetic diversity of parvoviruses and its infections in tilapia populations need to be evaluated in terms of pathogenicity and production losses in tilapia farming.
Genetic instability, a hallmark of cancer, can occur when the replication machinery encounters a barrier. The intra-S-phase checkpoint maintains stalled replication forks in a replication-competent ...configuration by phosphorylating replisome components and DNA repair proteins to prevent forks from catastrophically collapsing. Here, we report a novel function of the core Schizosaccharomyces pombe checkpoint sensor kinase, Rad3 (an ATR orthologue), that is independent of Chk1 and Cds1 (a CHK2 orthologue); Rad3(ATR) regulates the association of recombination factors with collapsed forks, thus limiting their genetic instability. We further reveal antagonistic roles for Rad3(ATR) and the 9-1-1 clamp - Rad3(ATR) restrains MRN- and Exo1-dependent resection, whereas the 9-1-1 complex promotes Exo1 activity. Interestingly, the MRN complex, but not its nuclease activity, promotes resection and the subsequent association of recombination factors at collapsed forks. The biological significance of this regulation is revealed by the observation that Rad3(ATR) prevents Exo1-dependent genome instability upstream of a collapsed fork without affecting the efficiency of recombination-mediated replication restart. We propose that the interplay between Rad3(ATR) and the 9-1-1 clamp functions to fine-tune the balance between the need for the recovery of replication through recombination and the risk of increased genome instability.
Objective
To develop a convenient double-locus scarless genome editing system in
Escherichia coli
, based on the type II
Streptococcus pyogenes
CRISPR/Cas9 and λ Red recombination cassette.
Results
A ...two-plasmid genome editing system was constructed. The large-sized plasmid harbors the
cas
9 and λ Red recombination genes (
gam
,
bet
, and
exo
), while the small-molecular plasmid can simultaneously express two different gRNAs (targeting genome RNAs). The recombination efficiency was tested by targeting the
gal
K,
lac
Z, and
dbp
A genes in
E. coli
with ssDNA or dsDNA. Resulting concurrent double-locus recombination efficiencies were 88 ± 5.5% (point mutation), 39.7 ± 4.3% (deletion/insertion), and 57.8 ± 3.4%–58.5 ± 4.1% (mixed point and deletion/insertion mutation), depending on 30 (ssDNA) or 40 bp (dsDNA) homologous side arms employed. In addition, the curing efficiency of the guide plasmid expressing gRNAs for negative selection was higher (96 ± 3% in 4 h) than the help plasmid carrying
cas
9 and λ Red (92 ± 2% in 9 h).
Conclusions
The new editing system is convenient and efficient for simultaneous double-locus recombination in the genome and should be favorable for high-throughput multiplex genome editing in synthetic biology and metabolic engineering.
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