Leaf development has been extensively studied on a genetic level. However, little is known about the inter- play between the developmental regulators and the cell cycle machinery--a link that ultimately affects leaf f...Leaf development has been extensively studied on a genetic level. However, little is known about the inter- play between the developmental regulators and the cell cycle machinery--a link that ultimately affects leaf form and size. miR319 is a conserved microRNA that regulates TCP transcription factors involved in multiple developmental pathways, including leaf development and senescence, organ curvature, and hormone biosynthesis and signaling. Here, we analyze the participation of TCP4 in the control of cell proliferation. A small increase in TCP4 activity has an immediate impact on leaf cell number, by significantly reducing cell proliferation. Plants with high TCP4 levels have a strong reduction in the expression of genes known to be active in G2-M phase of the cell cycle. Part of these effects is mediated by induction of miR396, which represses Growth-Regulating Factor （GRF） transcription factors. Detailed analysis revealed TCP4 to be a direct regulator of MIR396b. However, we found that TCP4 can control cell proliferation through additional pathways, and we identified a direct connection between TCP4 and ICK1/KRP1, a gene involved in the progression of the cell cycle. Our results show that TCP4 can activate different pathways that repress cell proliferation.展开更多
The use of filamentous fungi in bioremediation of heavy metal contamination has been developed recently. This research aims to observe the capability of filamentous fungi isolated from forest soil for bioremediation o...The use of filamentous fungi in bioremediation of heavy metal contamination has been developed recently. This research aims to observe the capability of filamentous fungi isolated from forest soil for bioremediation of mercury contamination in a substrate. Six fungal strains were selected based on their capability to grow in 25 mg/L Hg2＋-contaminated potato dextrose agar plates. Fungal strain KRP1 showed the highest ratio of growth diameter, 0.831, thus was chosen for further observation. Identification based on colony and cell morphology carried out by 18S rRNA analysis gave a 98% match to Aspergillusflavus strain KRP1. The fungal characteristics in mercury（II） contamination such as range of optimum pH, optimum temperature and tolerance level were 5.5-7 and 25-35℃ and 100 mg/L respectively. The concentration of mercury in the media affected fungal growth during lag phases. The capability of the fungal strain to remove the mercury（II） contaminant was evaluated in 100 mL sterile 10 mg/L Hg2＋-contaminated potato dextrose broth media in 250 mL Erlenmeyer flasks inoculated with 108 spore/mL fungal spore suspension and incubation at 30℃ for 7 days. The mercury（II） utilization was observed for flasks shaken in a 130 r/min orbital shaker （shaken） and non- shaken flasks （static） treatments. Flasks containing contaminated media with no fungal spores were also provided as control. All treatments were done in triplicate. The strain was able to remove 97.50% and 98.73% mercury from shaken and static systems respectively. A.flavus strain KRPI seems to have potential use in bioremediation of aqueous substrates containing mercury（II） through a biosorption mechanism.展开更多
文摘Leaf development has been extensively studied on a genetic level. However, little is known about the inter- play between the developmental regulators and the cell cycle machinery--a link that ultimately affects leaf form and size. miR319 is a conserved microRNA that regulates TCP transcription factors involved in multiple developmental pathways, including leaf development and senescence, organ curvature, and hormone biosynthesis and signaling. Here, we analyze the participation of TCP4 in the control of cell proliferation. A small increase in TCP4 activity has an immediate impact on leaf cell number, by significantly reducing cell proliferation. Plants with high TCP4 levels have a strong reduction in the expression of genes known to be active in G2-M phase of the cell cycle. Part of these effects is mediated by induction of miR396, which represses Growth-Regulating Factor （GRF） transcription factors. Detailed analysis revealed TCP4 to be a direct regulator of MIR396b. However, we found that TCP4 can control cell proliferation through additional pathways, and we identified a direct connection between TCP4 and ICK1/KRP1, a gene involved in the progression of the cell cycle. Our results show that TCP4 can activate different pathways that repress cell proliferation.
基金High gratitude to Directorate General of Higher Education, Ministry of Education and Culture, Republic of Indonesia for the full support through DIKTI Scholarship, Brawijaya University, and Yamaguchi University
文摘The use of filamentous fungi in bioremediation of heavy metal contamination has been developed recently. This research aims to observe the capability of filamentous fungi isolated from forest soil for bioremediation of mercury contamination in a substrate. Six fungal strains were selected based on their capability to grow in 25 mg/L Hg2＋-contaminated potato dextrose agar plates. Fungal strain KRP1 showed the highest ratio of growth diameter, 0.831, thus was chosen for further observation. Identification based on colony and cell morphology carried out by 18S rRNA analysis gave a 98% match to Aspergillusflavus strain KRP1. The fungal characteristics in mercury（II） contamination such as range of optimum pH, optimum temperature and tolerance level were 5.5-7 and 25-35℃ and 100 mg/L respectively. The concentration of mercury in the media affected fungal growth during lag phases. The capability of the fungal strain to remove the mercury（II） contaminant was evaluated in 100 mL sterile 10 mg/L Hg2＋-contaminated potato dextrose broth media in 250 mL Erlenmeyer flasks inoculated with 108 spore/mL fungal spore suspension and incubation at 30℃ for 7 days. The mercury（II） utilization was observed for flasks shaken in a 130 r/min orbital shaker （shaken） and non- shaken flasks （static） treatments. Flasks containing contaminated media with no fungal spores were also provided as control. All treatments were done in triplicate. The strain was able to remove 97.50% and 98.73% mercury from shaken and static systems respectively. A.flavus strain KRPI seems to have potential use in bioremediation of aqueous substrates containing mercury（II） through a biosorption mechanism.
