Genome-wide analyses of light-regulated genes in Aspergillus nidulans reveal a complex interplay between different photoreceptors and novel photoreceptor functions

Fungi sense light of different wavelengths using blue-, green-, and red-light photoreceptors. Blue light sensing requires the “white-collar” proteins with flavin as chromophore, and red light is sensed through phytochrome. Here we analyzed genome-wide gene expression changes caused by short-term, low-light intensity illumination with blue-, red- or far-red light in Aspergillus nidulans and found that more than 1100 genes were differentially regulated. The largest number of up- and downregulated genes depended on the phytochrome FphA and the attached HOG pathway. FphA and the white-collar orthologue LreA fulfill activating but also repressing functions under all light conditions and both appear to have roles in the dark. Additionally, we found about 100 genes, which are red-light induced in the absence of phytochrome, suggesting alternative red-light sensing systems. We also found blue-light induced genes in the absence of the blue-light receptor LreA. We present evidence that cryptochrome may be part of this regulatory cue, but that phytochrome is essential for the response. In addition to in vivo data showing that FphA is involved in blue-light sensing, we performed spectroscopy of purified phytochrome and show that it responds indeed to blue light

Citrobacter spp. (6.67%), Salmonella spp. (6.67%), Serratia spp. (6.67%), Bacillus spp

Abstract This research determined the microbial counts, antibiotics susceptibility and plas mid profile of the isolated bacteria of water samples fro m Arinta waterfall Ipole-Iloro Ekiti, Ekit i State, Nigeria. The total bacterial and colifo rm counts were done using pour plating technique while the susceptibility of the isolated microbes were determined using disc diffusion technique the plasmid profile of the isolates was determine using alkaline lysis method and agar gel electrophoresis. The mean total bacterial count of the water sample ranged 106 X 10 2 -15.5 X 10 3 CFU/ ml, wh ile the mean coliform count ranged 97.5 X 10 2 -6.50 X 10 3 CFU/ ml. The identified bacteria isolates and their percentage distribution are Escherichia coli which have the highest percentage (31.1%), Klebsiella spp. A mong these ten species, multip le antibiotics resistant bacteria were identified. The most active antibiotics were oflo xacin (14%), ciproflo xacin (28%) and gentamicin (17%). 99.6% of the isolates exh ibited multip le antibiotic resistances. Eight bacterial isolates harbored plasmids all o f wh ich were not less than 2.51kbp in mo lecular weight. Hence, it showed that the gene coding for the isolates were located on the plasmid DNA while the remaining isolates which have no plasmid might showed gene coding for antibiotic resistance being located on chromosomal DNA. The occurrence of plasmid mediated mu ltidrug resistant in bacteria in this surface water lightens the public health concern

Impact of agricultural technology adoption on asset ownership: the case of improved cassava varieties in Nigeria

Published online: 28 September 201