Functions of Fun30 Chromatin Remodeler in Regulating Cellular Resistance to Genotoxic Stress

The Saccharomyces cerevisiae Fun30 chromatin remodeler has recently been shown to facilitate long-range resection of DNA double strand break (DSB) ends, which proceeds homologous recombination (HR). This is believed to underlie the role of Fun30 in promoting cellular resistance to DSB inducing agent camptothecin. We show here that Fun30 also contributes to cellular resistance to genotoxins methyl methanesulfonate (MMS) and hydroxyurea (HU) that can stall the progression of DNA replication. We present evidence implicating DNA end resection in Fun30-dependent MMS-resistance. On the other hand, we show that Fun30 deletion suppresses the MMS- and HU-sensitivity of cells lacking the Rad5/Mms2/Ubc13-dependent error-free DNA damage tolerance mechanism. This suppression is not the result of a reduction in DNA end resection, and is dependent on the key HR component Rad51. We further show that Fun30 negatively regulates the recovery of rad5Δ mutant from MMS induced G2/M arrest. Therefore, Fun30 has two functions in DNA damage repair: one is the promotion of cellular resistance to genotoxic stress by aiding in DNA end resection, and the other is the negative regulation of a Rad51-dependent, DNA end resection-independent mechanism for countering replicative stress. The latter becomes manifest when Rad5 dependent DNA damage tolerance is impaired. In addition, we find that the putative ubiquitin-binding CUE domain of Fun30 serves to restrict the ability of Fun30 to hinder MMS- and HU-tolerance in the absence of Rad5.     

Biodegradation of alkali lignin by a newly isolated Rhodococcus pyridinivorans CCZU-B16

Bioprocess and Biosystems Engineering - Based on the Prussian blue spectrophotometric method, one high-throughput screening strategy for screening lignin-degrading microorganisms was built on...     

Complete Genome Sequence of the Bacteriophage YMC01/01/P52 PAE BP,Which Causes Lysis of Verona Integron-Encoded Metallo-β-Lactamase-Producing,Carbapenem-Resistant Pseudomonas aeruginosa

Multidrug-resistant Pseudomonas aeruginosa commonly causes serious nosocomial infections. In this study, a novel lytic bacteriophage belonging to a member of the family Podoviridae, YMC01/01/P52 PAE BP, which infects carbapenem-resistant Pseudomonas aeruginosa, was isolated and characterized. YMC01/01/P52 PAE BP genome was analyzed by whole-genome sequencing and putative function identification. The bacteriophage genome consists of a double-stranded linear DNA genome of 49,381 bp with a GC content of 62.16%.     

Synthesis of novel nitric oxide (NO)-releasing esters of timolol

A novel class of timolol derivatives with nitric oxide (NO)-donating moieties achieved chemical stability yet under physiologically relevant conditions released timolol and NO. Hindered esters A were designed and synthesized, whose ‘triggered’ release relied on enzymatic hydrolysis of the nitrate ester in A to B, that in turn cyclized to liberate timolol.     

Analysis of the structure and expression of the c-myc oncogene in cervical tumor and in cervical tumor-derived cell lines

The structure of the c-myc oncogene in 17 cervical tumors and patient-matched nontumor tissues from Chinese patients residing in Taiwan was analysed. In contrast to recent reports on Mexican patients, none of the samples showed rearrangements and sequence amplification in the c-myc gene. The discrepancy may be explained by different carcinogenesis mechanisms being in operation in different geographic regions. Although no structural alterations in the c-myc gene were found in seven cervical carcinoma cell lines analysed, Northern blot analysis indicated different levels of c-myc gene expression which may be related to the presence of human papillomavirus (HPV) sequence in the cell and suggests a possible c-myc-hpv interaction in some stages of the transformation process.     

Species interactions between estuarine detritivores: inhibition or facilitation?

Native Hawaiian estuarine detritivores; the prawn Macrobrachium grandimanus, and the neritid gastropod Neritina vespertina, were maintained in flow-through microcosms with conditioned leaves from two riparian tree species, Hau (Hibiscus tiliaceus) and guava (Psidium guajava). Their ability to beak down leaf detritus was determined when alone and when they were together. In single-species treatments, N. vespertina processed leaves from both trees at higher rates than M. grandimanus, but in combined treatments, facilitation occurred when the substrate consisted of Hau leaves, and interference occurred when the substrate consisted of guava leaves. From this, we conclude that whether detritivore species are functionally redundant, facilitating or inhibiting in their processing of detritus depends not only on the detritivore species, but also on the species composition of the detritus food source.