Biology subjects

Tang, A.

Publications and source records attributed to Tang, A..

4 recordsLinked to original sources

bioRxiv2018

Potential PGPR properties of cellulolytic, nitrogen-fixing, and phosphate-solubilizing bacteria of a rehabilitated tropical forest soil

In the midst of major soil degradation and erosion faced by tropical ecosystems, rehabilitated forests are established to avoid further deterioration of forest land. In this context, cellulolytic, nitrogen-fixing (N-fixing), and phosphate-solubilizing bacteria are very important functional groups in regulating the elemental cycle and plant nutrition, hence replenishing the nutrient content in forest soil. As other potential plant growth-promoting (PGP) rhizobacteria, these functional bacteria could have cross-functional abilities or beneficial traits that are essential for plants and improve their growths. This study was conducted to isolate, identify, and characterize selected PGP properties of these 3 functional groups of bacteria from tropical rehabilitated forest soils at Universiti Putra Malaysia Bintulu Sarawak Campus, Malaysia. Isolated cellulolytic, N-fixing and phosphate-solubilizing bacteria were characterized for respective functional activities, biochemical properties, molecularly identified, and assessed for PGP assays based on seed germination and indole-3-acetic acid (IAA) production. Out of 15 identified bacterial isolates exhibiting beneficial phenotypic traits, a third belong to genus Burkholderia and a fifth to Stenotrophomonas sp. with both genera consisting of members from two different functional groups. Among the tested bacterial strains, isolate Serratia nematodiphila C46d, Burkholderia nodosa NB1, and Burkholderia cepacia PC8 showed outstanding cellulase, N-fixing, and phosphate-solubilizing activities, respectively. The results of the experiments confirmed the multiple PGP traits of selected bacterial isolates based on respective high functional activities, root, shoot lengths, and seedling vigour improvements when bacterized on mung bean seeds, as well as presented some significant IAA productions. The results of this study indicated that these functional bacterial strains could potentially be included in future biotechnological screenings to produce beneficial synergistic effects via their versatile properties on improving soil fertility and possible crop growth stimulation.

microbiology↗

bioRxiv2018

Epigenome-wide study uncovers tau pathology-driven changes of chromatin organization in the aging human brain

Accumulation of tau and amyloid-{beta} are two pathologic hallmarks of Alzheimers disease (AD). Here, we conducted an epigenome-wide association study using the H3K9 acetylation (H3K9Ac) mark in 669 aged human prefrontal cortices: in contrast to amyloid-{beta}, tau protein burden had a broad effect on the epigenome, affecting 5,590 out of 26,384 H3K9Ac domains. Tau-related alterations aggregated in large genomic segments reflecting spatial chromatin organization, and the magnitude of these effects correlated with the segments nuclear lamina association. We confirmed the functional relevance of these chromatin changes by demonstrating (1) consistent transcriptional changes in three independent datasets and (2) similar findings in two AD mouse models. Finally, we found that tau overexpression in iPSC-derived neurons disrupted chromatin organization and that these effects could be blocked by a small molecule predicted to reverse the tau effect. Thus, we report large-scale tau-driven chromatin rearrangements in the aging human brain that may be reversible with HSP90 inhibitors.

neuroscience↗

bioRxiv2018

A multi-omic atlas of the human frontal cortex for aging and Alzheimer's disease research

We initiated the systematic profiling of the dorsolateral prefrontal cortex obtained from a subset of autopsied individuals enrolled in the Religious Orders Study (ROS) or the Rush Memory and Aging Project (MAP), which are jointly designed and belong to a very few prospective studies of aging and dementia with detailed, longitudinal cognitive phenotyping during life and a quantitative, structured neuropathologic examination after death for >3,322 subjects. Here, we outline the first generation of data including genome-wide genotypes (n=2,090), whole genome sequencing (n=1,179), DNA methylation (n=740), chromatin immunoprecipitation with sequencing using an anti-Histone 3 Lysine 9 acetylation (H3K9Ac) antibody (n=712), RNA sequencing (n=638), and miRNA profile (n=702). Generation of other omic data including ATACseq, proteomic and metabolomics profiles is ongoing. Thanks to its prospective design and recruitment of older, non-demented individuals, these data can be repurposed to investigate a large number of syndromic and quantitative neuroscience phenotypes. The many subjects that are cognitively non-impaired at death also offer insights into the biology of the human brain in older non-impaired individuals.

cell biology↗

bioRxiv2016

Dissecting the role of non-coding RNAs in the accumulation of amyloid and tau neuropathologies in Alzheimer’s disease

BackgroundGiven multiple studies of brain microRNA (miRNA) in relation to Alzheimers disease (AD) with few consistent results and the heterogeneity of this disease, the objective of this study was to explore their mechanism by evaluating their relation to different elements of Alzheimers disease pathology, confounding factors and mRNA expression data from the same subjects in the same brain region.\n\nResultsWe report analyses of expression profiling of miRNA (n=700 subjects) and lincRNA (n=540 subjects) from the dorsolateral prefrontal cortex of individuals participating in two longitudinal cohort studies of aging. Evaluating well-established (miR-132, miR-129), we confirm their association with pathologic AD in our dataset, and then characterize their in disease role in terms of neuritic {beta}-amyloid plaques and neurofibrillary tangle pathology. Additionally, we identify one new miRNA (miR-99) and four lincRNA that are associated with these traits. Many other previously reported associations of microRNA with AD are associated with the confounders quantified in our longitudinal cohort. Finally, by performing analyses integrating both miRNA and RNA sequence data from the same individuals (525 samples), we characterize the impact of AD associated miRNA on human brain expression: we show that the effects of miR-132 and miR-129-5b converge on certain genes such as EP300 and find a role for miR200 and its target genes in AD using an integrated miRNA/mRNA analysis.\n\nConclusionsOverall, miRNAs play a modest role in human AD, but we observe robust evidence that a small number of miRNAs are responsible for specific alterations in the cortical transcriptome that are associated with AD.

neuroscience↗