On self-similar finite-time blowups of the De Gregorio model on the real line

We show that the De Gregorio model on the real line admits infinitely many compactly supported, self-similar solutions that are distinct under rescaling and will blow up in finite time. These self-similar solutions fall into two classes: the basic class and the general class. The basic class consists of countably infinite solutions that are eigenfunctions of a self-adjoint compact operator. In particular, the leading eigenfunction coincides with the finite-time singularity solution of the De Gregorio model recently obtained by numerical approaches. The general class consists of more complicated solutions that can be obtained by solving nonlinear eigenvalue problems associated with the same compact operator.Comment: 33 page

Prevalence of the GJB2 IVS1+1G >A mutation in Chinese hearing loss patients with monoallelic pathogenic mutation in the coding region of GJB2

<p>Abstract</p> <p>Background</p> <p>Mutations in the GJB2 gene are the most common cause of nonsyndromic recessive hearing loss in China. In about 6% of Chinese patients with severe to profound sensorineural hearing impairment, only monoallelic <it>GJB2 </it>mutations known to be either recessive or of unclear pathogenicity have been identified. This paper reports the prevalence of the <it>GJB2 </it>IVS1+1G>A mutation in a population of Chinese hearing loss patients with monoallelic pathogenic mutation in the coding region of <it>GJB2</it>.</p> <p>Methods</p> <p>Two hundred and twelve patients, screened from 7133 cases of nonsyndromic hearing loss in China, with monoallelic mutation (mainly frameshift and nonsense mutation) in the coding region of <it>GJB2 </it>were examined for the <it>GJB2 </it>IVS1+1G>A mutation and mutations in the promoter region of this gene. Two hundred and sixty-two nonsyndromic hearing loss patients without <it>GJB2 </it>mutation and 105 controls with normal hearing were also tested for the <it>GJB2 </it>IVS1+1G>A mutation by sequencing.</p> <p>Results</p> <p>Four patients with monoallelic mutation in the coding region of <it>GJB2 </it>were found carrying the <it>GJB2 </it>IVS1+1G>A mutation on the opposite allele. One patient with the <it>GJB2 </it>c.235delC mutation carried one variant, -3175 C>T, in exon 1 of <it>GJB2</it>. Neither <it>GJB2 </it>IVS1+1G>A mutation nor any variant in exon 1 of <it>GJB2 </it>was found in the 262 nonsyndromic hearing loss patients without <it>GJB2 </it>mutation or in the 105 normal hearing controls.</p> <p>Conclusion</p> <p>Testing for the <it>GJB2 </it>IVS 1+1 G to A mutation explained deafness in 1.89% of Chinese <it>GJB2 </it>monoallelic patients, and it should be included in routine testing of patients with <it>GJB2 </it>monoallelic pathogenic mutation.</p

Streptomyces tirandamycinicus sp. nov., a Novel Marine Sponge-Derived Actinobacterium With Antibacterial Potential Against Streptococcus agalactiae

A novel actinobacterium, strain HNM0039T, 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 Streptomyces. Based on the 16S rRNA gene sequence analysis, strain HNM0039T was closely related to Streptomyces wuyuanensis CGMCC 4.7042T (99.38%) and Streptomyces spongiicola HNM0071T (99.05%). The organism formed a well-delineated subclade with S. wuyuanensis CGMCC 4.7042T and S. spongiicola HNM0071T in the Streptomyces 16S rRNA gene tree. Multi-locus sequence analysis (MLSA) based on five house-keeping gene alleles (atpD, gyrB, rpoB, recA, trpB) further confirmed their relationship. DNA–DNA relatedness between strain HNM0039T and its closest type strains, namely S. wuyuanensis CGMCC 4.7042T and S. spongiicola HNM0071T, were 46.5 and 45.1%, respectively. The average nucleotide identity (ANI) between strain HNM0039T and its two neighbor strains were 89.65 and 91.44%, respectively. The complete genome size of strain HNM0039T 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 HNM0039T. Among them, the tirandamycin biosynthetic gene cluster has been characterized completely. The crude extract of strain HNM0039T exhibited potent antibacterial activity against Streptococcus agalactiae 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 HNM0039T represents a novel species of the genus Streptomyces whose name was proposed as Streptomyces tirandamycinicus sp. nov. The type strain is HNM0039T (= CCTCC AA 2018045T = KCTC 49236T)

Extremely discrepant mutation spectrum of SLC26A4 between Chinese patients with isolated Mondini deformity and enlarged vestibular aqueduct

<p>Abstract</p> <p>Background</p> <p>Mutations in <it>SLC26A4 </it>cause Pendred syndrome (hearing loss with goiter) or DFNB4 (non-syndromic hearing loss with inner ear malformation, such as enlarged vestibular aqueduct or Mondini deformity). The relationship between mutations in <it>SLC26A4 </it>and Mondini deformity without enlarged vestibular aqueduct has not been studied in any Chinese deaf population. The purpose of this study was to assess whether mutations in the <it>SLC26A4 </it>gene cause Mondini deformity without an enlarged vestibular aqueduct (isolated Mondini deformity) in a Chinese population.</p> <p>Methods</p> <p>In total, 144 patients with sensorineural hearing loss were included and subjected to high-resolution temporal bone CT. Among them, 28 patients with isolated Mondini dysplasia (MD group), 50 patients with enlarged vestibular aqueduct with Mondini dysplasia (EVA with MD group), 50 patients with enlarged vestibular aqueduct without Mondini dysplasia (EVA group), and 16 patients with other types of inner ear malformations (IEM group) were identified. The coding exons of <it>SLC26A4 </it>were analyzed in all subjects.</p> <p>Results</p> <p>DNA sequence analysis of <it>SLC26A4 </it>was performed in all 144 patients. In the different groups, the detection rate of the <it>SLC26A4 </it>mutation differed. In the isolated MD group, only one single allelic mutation in <it>SLC26A4 </it>was found in one patient (1/28, 3.6%). In the EVA with MD group, biallelic and monoallelic <it>SLC26A4 </it>mutations were identified in 46 patients (46/50, 92.0%) and three patients (3/50, 6.0%), respectively. Also, in the EVA group, biallelic and monoallelic <it>SLC26A4 </it>mutations were identified in 46 patients (46/50, 92.0%) and three patients (3/50, 6.0%), respectively. These percentages were identical to those in the EVA plus MD group. Only two patients carried monoallelic mutations of the <it>SLC26A4 </it>gene in the IEM group (2/16, 12.5%). There were significant differences in the frequency of <it>SLC26A4 </it>mutation among the groups (P < 0.001). The detection rate of <it>SLC26A4 </it>mutation in the isolated MD group was significantly lower than in the EVA group (with or without MD; P < 0.001), and there was no significant difference in the detection rate of <it>SLC26A4 </it>between the MD group and IEM group (P > 0.5).</p> <p>Conclusion</p> <p>Although mutations in the <it>SLC26A4 </it>gene were frequently found in Chinese EVA patients with and without MD, there was no evidence to show a relationship between isolated MD and the <it>SLC26A4 </it>gene in the Chinese population examined. Hearing impairment in patients with isolated MD may be caused by factors other than mutations in the <it>SLC26A4 </it>gene.</p

Molecular Etiology of Hearing Impairment in Inner Mongolia: mutations in SLC26A4 gene and relevant phenotype analysis

<p>Abstract</p> <p>Background</p> <p>The molecular etiology of hearing impairment in Chinese has not been thoroughly investigated. Study of <it>GJB2 </it>gene revealed that 30.4% of the patients with hearing loss in Inner Mongolia carried <it>GJB2 </it>mutations. The <it>SLC26A4 </it>gene mutations and relevant phenotype are analyzed in this study.</p> <p>Methods</p> <p>One hundred and thirty-five deaf patients were included. The coding exons of <it>SLC26A4 </it>gene were sequence analyzed in 111 patients, not including 22 patients carrying bi-allelic <it>GJB2 </it>mutations or one patient carrying a known <it>GJB2 </it>dominant mutation as well as one patient with <it>mtDNA </it>1555A>G mutation. All patients with <it>SLC26A4 </it>mutations or variants were subjected to high resolution temporal bone CT scan and those with confirmed enlarged vestibular aqueduct and/or other inner ear malformation were then given further ultrasound scan of thyroid and thyroid hormone assays.</p> <p>Results</p> <p>Twenty-six patients (19.26%, 26/135) were found carrying <it>SLC26A4 </it>mutation. Among them, 17 patients with bi-allelic <it>SLC26A4 </it>mutations were all confirmed to have EVA or other inner ear malformation by CT scan. Nine patients were heterozygous for one <it>SLC26A4 </it>mutation, including 3 confirmed to be EVA or EVA and Mondini dysplasia by CT scan. The most common mutation, IVS7-2A>G, accounted for 58.14% (25/43) of all <it>SLC26A4 </it>mutant alleles. The shape and function of thyroid were confirmed to be normal by thyroid ultrasound scan and thyroid hormone assays in 19 of the 20 patients with EVA or other inner ear malformation except one who had cystoid change in the right side of thyroid. No Pendred syndrome was diagnosed.</p> <p>Conclusion</p> <p>In Inner Mongolia, China, mutations in <it>SLC26A4 </it>gene account for about 12.6% (17/135) of the patients with hearing loss. Together with <it>GJB2 </it>(23/135), <it>SLC26A4 </it>are the two most commonly mutated genes causing deafness in this region. Pendred syndrome is not detected in this deaf population. We established a new strategy that detects <it>SLC26A4 </it>mutations prior to the temporal bone CT scan to find EVA and inner ear malformation patients. This model has a unique advantage in epidemiologic study of large deaf population.</p

Comprehensive molecular etiology analysis of nonsyndromic hearing impairment from typical areas in China

<p>Abstract</p> <p>Background</p> <p>Every year, 30,000 babies are born with congenital hearing impairment in China. The molecular etiology of hearing impairment in the Chinese population has not been investigated thoroughly. To provide appropriate genetic testing and counseling to families, we performed a comprehensive investigation of the molecular etiology of nonsyndromic deafness in two typical areas from northern and southern China.</p> <p>Methods</p> <p>A total of 284 unrelated school children with hearing loss who attended special education schools in China were enrolled in this study, 134 from Chifeng City in Inner Mongolia and the remaining 150 from Nangtong City in JiangSu Province. Screening was performed for <it>GJB2</it>, <it>GJB3</it>, <it>GJB6</it>, <it>SLC26A4</it>, <it>12S rRNA</it>, <it>and tRNA</it>^{<it>ser</it>(<it>UCN</it>)}genes in this population. All patients with <it>SLC26A4 </it>mutations or variants were subjected to high-resolution temporal bone CT scan to verify the enlarged vestibular aqueduct.</p> <p>Results</p> <p>Mutations in the <it>GJB2 </it>gene accounted for 18.31% of the patients with nonsyndromic hearing loss, 1555A>G mutation in mitochondrial DNA accounted for 1.76%, and <it>SLC26A4 </it>mutations accounted for 13.73%. Almost 50% of the patients with nonsyndromic hearing loss in these typical Chinese areas carried <it>GJB2 </it>or <it>SLC26A4 </it>mutations. No significant differences in mutation spectrum or prevalence of <it>GJB2 </it>and <it>SLC26A4 </it>were found between the two areas.</p> <p>Conclusion</p> <p>In this Chinese population, 54.93% of cases with hearing loss were related to genetic factors. The <it>GJB2 </it>gene accounted for the etiology in about 18.31% of the patients with hearing loss, <it>SLC26A4 </it>accounted for about 13.73%, and <it>mtDNA </it>1555A>G mutation accounted for 1.76%. Mutations in <it>GJB3, GJB6</it>, and <it>mtDNA tRNA</it>^{<it>ser</it>(<it>UCN</it>)}were not common in this Chinese cohort. Conventionally, screening is performed for <it>GJB2</it>, <it>SLC26A4</it>, and mitochondrial <it>12S rRNA </it>in the Chinese deaf population.</p