Human Mitochondrial tRNA Mutations in Maternally Inherited Deafness

AbstractMutations in mitochondrial tRNA genes have been shown to be associated with maternally inherited syndromic and non-syndromic deafness. Among those, mutations such as tRNALeu(UUR)3243A>G associated with syndromic deafness are often present in heteroplasmy, and the non-syndromic deafness-associated tRNA mutations including tRNASer(UCN)7445A>G are often in homoplasmy or in high levels of heteroplasmy. These tRNA mutations are the primary factors underlying the development of hearing loss. However, other tRNA mutations such as tRNAThr15927G>A and tRNASer(UCN)7444G>A are insufficient to produce a deafness phenotype, but always act in synergy with the primary mitochondrial DNA mutations, and can modulate their phenotypic manifestation. These tRNA mutations may alter the structure and function of the corresponding mitochondrial tRNAs and cause failures in tRNAs metabolism. Thereby, the impairment of mitochondrial protein synthesis and subsequent defects in respiration caused by these tRNA mutations, results in mitochondrial dysfunctions and eventually leads to the development of hearing loss. Here, we summarized the deafness-associated mitochondrial tRNA mutations and discussed the pathophysiology of these mitochondrial tRNA mutations, and we hope these data will provide a foundation for the early diagnosis, management, and treatment of maternally inherited deafness

Cavernous Transformation of the Portal Vein Might Increase the Risk of Liver Abscess

Cavernous transformation of the portal vein (CTPV) is not quite common in adults, and cases with CTPV and acute liver abscess are lacking. We report a patient with CTPV inducing extrahepatic and intrahepatic obstruction, finally leading to acute liver abscess due to bile duct infection. We aim to find out the possible relationship between CTPV and acute liver abscess. A 45-year-old female patient was admitted to our hospital for recurrent upper abdominal pain and distension for one year, aggravated with fever for three years. A diagnosis of CTPV and liver abscess was made by 16-slice computed tomography. Effective antibiotics and drainage were used for this patients, and she was eventually cured. When treating patients with CTPV, extrahepatic and intrahepatic obstruction, one should be aware of the presence of acute liver abscess, and empirical antibiotics might be valuable

Novel and Neuroprotective Tetranortriterpenoids from Chinese Mangrove Xylocarpus granatum Koenig

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Cloning and expression profiling of the VLDLR gene associated with egg performance in duck (Anas platyrhynchos)

<p>Abstract</p> <p>Background</p> <p>The very low density lipoprotein receptor gene (<it>VLDLR</it>), a member of the low density lipoprotein receptor (<it>LDLR</it>) gene family, plays a crucial role in the synthesis of yolk protein precursors in oviparous species. Differential splicing of this gene has been reported in human, rabbit and rat. In chicken, studies showed that the VLDLR protein on the oocyte surface mediates the uptake of yolk protein precursors into growing oocytes. However, information on the <it>VLDLR </it>gene in duck is still scarce.</p> <p>Methods</p> <p>Full-length duck <it>VLDLR </it>cDNA was obtained by comparative cloning and rapid amplification of cDNA ends (RACE). Tissue expression patterns were analysed by semi-quantitative reverse-transcription polymerase chain reaction (RT-PCR). Association between the different genotypes and egg performance traits was investigated with the general linear model (GLM) procedure of the SAS^®software package.</p> <p>Results</p> <p>In duck, two <it>VLDLR </it>transcripts were identified, one transcript (variant-a) containing an O-linked sugar domain and the other (variant-b) not containing this sugar domain. These transcripts share ~70 to 90% identity with their counterparts in other species. A phylogenetic tree based on amino acid sequences showed that duck VLDLR proteins were closely related with those of chicken and zebra finch. The two duck <it>VLDLR </it>transcripts are differentially expressed i.e. <it>VLDLR-a </it>is mainly expressed in muscle tissue and <it>VLDLR-b </it>in reproductive organs. We have localized the duck <it>VLDLR </it>gene on chromosome Z. An association analysis using two completely linked SNP sites (T/C at position 2025 bp of the ORF and G/A in intron 13) and records from two generations demonstrated that the duck <it>VLDLR </it>gene was significantly associated with egg production (P < 0.01), age of first egg (P < 0.01) and body weight of first egg (P < 0.05).</p> <p>Conclusions</p> <p>Duck and chicken <it>VLDLR </it>genes probably perform similar function in the development of growing oocytes and deposition of yolk lipoprotein. Therefore, <it>VLDLR </it>could be a candidate gene for duck egg performance and be used as a genetic marker to improve egg performance in ducks.</p

Expression of Tau Pathology-Related Proteins in Different Brain Regions: A Molecular Basis of Tau Pathogenesis

Microtubule-associated protein tau is hyperphosphorylated and aggregated in affected neurons in Alzheimer disease (AD) brains. The tau pathology starts from the entorhinal cortex (EC), spreads to the hippocampus and frontal and temporal cortices, and finally to all isocortex areas, but the cerebellum is spared from tau lesions. The molecular basis of differential vulnerability of different brain regions to tau pathology is not understood. In the present study, we analyzed brain regional expressions of tau and tau pathology-related proteins. We found that tau was hyperphosphorylated at multiple sites in the frontal cortex (FC), but not in the cerebellum, from AD brain. The level of tau expression in the cerebellum was about 1/4 of that seen in the frontal and temporal cortices in human brain. In the rat brain, the expression level of tau with three microtubule-binding repeats (3R-tau) was comparable in the hippocampus, EC, FC, parietal-temporal cortex (PTC), occipital-temporal cortex (OTC), striatum, thalamus, olfactory bulb (OB) and cerebellum. However, the expression level of 4R-tau was the highest in the EC and the lowest in the cerebellum. Tau phosphatases, kinases, microtubule-related proteins and other tau pathology-related proteins were also expressed in a region-specific manner in the rat brain. These results suggest that higher levels of tau and tau kinases in the EC and low levels of these proteins in the cerebellum may accounts for the vulnerability and resistance of these representative brain regions to the development of tau pathology, respectively. The present study provides the regional expression profiles of tau and tau pathology-related proteins in the brain, which may help understand the brain regional vulnerability to tau pathology in neurodegenerative tauopathies

Odor, Not Performance, Dictates \u3cem\u3eBemisia tabaci\u3c/em\u3e\u27s Selection Between Healthy and Virus Infected Plants

Although, insect herbivores are generally thought to select hosts that favor the fitness of their progeny, this “mother-knows-best” hypothesis may be challenged by the presence of a plant virus. Our previous study showed that the whitefly, Bemisia tabaci, the obligate vector for transmitting Tomato yellow leaf curl virus (TYLCV), preferred to settle and oviposit on TYLCV-infected rather than healthy host plant, Datura stramonium. The performances of B. tabaci larvae and adults were indeed improved on virus-infected D. stramonium, which is consistent with “mother-knows-best” hypothesis. In this study, B. tabaci Q displayed the same preference to settle and oviposit on Tomato spotted wilt virus (TSWV)-infected host plants, D. stramonium and Capsicum annuum, respectively. As a non-vector of TSWV, however, insect performance was impaired since adult body size, longevity, survival, and fecundity were reduced in TSWV infected D. stramonium. This appears to be an odor-mediated behavior, as plant volatile profiles are modified by viral infection. Infected plants have reduced quantities of o-xylene and α-pinene, and increased levels of phenol and 2-ethyl-1-hexanol in their headspace. Subsequent behavior experiments showed that o-xylene and α-pinene are repellant, while phenol and 2-ethyl-1-hexanol are attractive. This indicates that the preference of B. tabaci for virus-infected plants is modulated by the dynamic changes in the volatile profiles rather than the subsequent performances on virus-infected plants