Fungal-bacterial biofilm mediated heavy metal rhizo-remediation

Heavy metal pollution due to excessive use of chemical fertilizers (CF) causes a major damage to the environment. Microbial consortia, closely associated with the rhizosphere are able to remediate heavy metal-contaminated soil by reducing plant toxicity. Thus, this study was undertaken to examine the remedial effects of microbial biofilms against contaminated heavy metals. Fungi and bacteria isolated from soil were screened for their tolerance against Cd2+, Pb2+ and Zn2+. Fungal-bacterial biofilms (FBBs) were developed with the highest tolerant isolates and were further screened for their bioremediation capabilities against heavy metals. The best biofilm was evaluated for its rhizoremediation capability with different CF combinations using a pot experiment conducted under greenhouse conditions with potato. Three bacterial and two fungal isolates were selected to develop FBBs upon the tolerance index (TI) percentage. Significantly (P < 0.05) the highest metal removal percentage was observed in Trichoderma harzianum and Bacillus subtilis biofilm under in situ condition. The biofilm with 50% of recommended CF (50CB) significantly (P < 0.05) reduced the soil available Pb2+ by 77%, Cd2+ by 78% and Zn2+ by 62% compared to 100% recommended CF (100C). In comparison to initial soil, it was 73%, 76% and 57% lower of Pb2+, Cd2+ and Zn2+, respectively. In addition, 50CB treatment significantly (P < 0.05) reduced the metal penetration into the tuber tissues in comparison with 100C. Thus, it is concluded that T. harzianum–B. subtilis biofilm is an ideal combination to remediate soil contaminated with Cd2+, Pb2+ and Zn2+.

Synergistic and concentration-dependent toxicity of multiple heavy metals compared with single heavy metals in Conocarpus lancifolius

While heavy metals (HMs) naturally occur in soil, anthropogenic activities can increase the level of these toxic elements. Conocarpus lancifolius Engl. (Combretaceae) was investigated as a potential phytoremediator of soils contaminated with HM containing crude oil. This study assessed the potential of C. lancifolius (CL), a locally available plant species in Kuwait, for resolving local issues of the HM-contaminated soils. The absorption, accumulation, and distribution of three toxic HMs (Cd, Ni, and Pb) and essential metals (Fe, Mg, and metalloid Se) were examined, and their role in plant toxicity and tolerance was evaluated. Conocarpus lancifolius plants were exposed to two different concentrations of single and mixed HMs for 30 days. The accumulation of HMs was determined in the roots, leaves, stems, and the soil using ICP/MS. Biomass, soil pH, proline and protein content, and bioaccumulation, extraction, and translocation factors were measured. The bioaccumulation, extraction, and transcription factors were all >1, indicating CC is a hyperaccumulator of HM. The HM accumulation in CL was concentration-dependent and depended on whether the plants were exposed to individual or mixed HMs. The C.C leaves, stems, and roots showed a significant accumulation of antioxidant constituents, such as proline, protein, Fe, Mg, and Se. There was an insignificant increase in the soil pH, and a decrease in plant biomass and a significant increase in protein, and osmoprotective-proline as a result of the interaction of mixed heavy metals that are more toxic than single heavy metals. This study indicates that C. lancifolius is a good candidate for phytoremediation of multiple HM-contaminated soils. Further studies to establish the phyto-physiological effect of multiple heavy metals are warranted.

Discovery of (meth)acrylate polymers that resist colonization by fungi associated with pathogenesis and biodeterioration

Fungi have major, negative socioeconomic impacts, but control with bioactive agents is increasingly restricted, while resistance is growing. Here, we describe an alternative fungal control strategy via materials operating passively (i.e., no killing effect). We screened hundreds of (meth)acrylate polymers in high throughput, identifying several that reduce attachment of the human pathogen Candida albicans, the crop pathogen Botrytis cinerea, and other fungi. Specific polymer functional groups were associated with weak attachment. Low fungal colonization materials were not toxic, supporting their passive, anti-attachment utility. We developed a candidate monomer formulation for inkjet-based 3D printing. Printed voice prosthesis components showed up to 100% reduction in C. albicans biofilm versus commercial materials. Furthermore, spray-coated leaf surfaces resisted fungal infection, with no plant toxicity. This is the first high-throughput study of polymer chemistries resisting fungal attachment. These materials are ready for incorporation in products to counteract fungal deterioration of goods, food security, and health.

IDENTIFIKASI FITOKIMIA, UJI AKTIVITAS ANTIOKSIDAN DENGAN METODE 1.1-diphenyl-2-picrylhydrazyl (DPPH), DAN TOKSISITAS DENGAN METODE Brine Shrimp Lethality Test (BSLT) DARI EKSTRAK ETANOL TANGKAI BUAH PINANG YAKI (Areca vestiaria Giseke)

ABSTRACT Pinang Yaki (Areca vestiaria Giseke) which is a kind of wild palm, is a multi-functional plant. The people of North Sulawesi empirically use this plant to cure various diseases. In a previous study that said leaves, seeds and even the seed skin of areca nut have very high antioxidant content. Because of the large amount of antioxidants contained in Pinang Yaki plants, the study wanted to examine the compound content of the stalks of this plant. This study aims to determine the phytochemical content, ability of antioxidant activity, and plant toxicity, so that later it can be used as medicine. The results of this study indicate that the ethanol extract of areca fruit stalk has flavonoids, saponins, triterpenoids which have the potential as antioxidants and have a strong Inhibition Concetration 50 (IC50) value, ie, 16.52 μg / mL based on the 1.1-diphenyl-2-picrylhydrazyl method (DPPH), and the level of toxicity, namely the value of Lethality Concetration 50 (LC50) of 602 μg / mL which was carried out by the Brine Shrimp Lethality Test (BSLT) method. Keywords: Areca vestiaria Giseke, Antioxidants, Toxicity, DPPH, BSLT ABSTRAK Pinang Yaki (Areca vestiaria Giseke) yang merupakan sejenis palem liar, merupakan tanaman yang multi fungsi. Masyarakat Sulawesi Utara secara empiris menggunakan tanaman ini untuk menyembuhkan berbagai macam penyakit. Pada penelitian yang sebelumnya mengatakan bahwa daun, biji bahkan kulit biji dari Pinang Yaki mempunyai kandungan antioksidan yang sangat tinggi. Oleh karena banyaknya kandungan antioksidan yang terkandung dalam tanaman Pinang Yaki maka peneliti ingin meneliti kandungan senyawa dari tangkai buah tanaman ini. Penelitian ini bertujuan untuk mengetahui kandungan fitokimia, kemampuan aktivitas antioksidan, dan toksisitas tanaman, agar nantinya bisa digunakan sebagai obat. Hasil penelitian ini menunjukkan bahwa ekstrak etanol tangkai buah Pinang Yaki memiliki kandungan flavonoid, saponin, triterpenoid yang berpotensi sebagai antioksidan dan memiliki nilai Inhibisi Concetration 50 (IC50) yang sangat kuat yakni, 16.52 μg/mL berdasarkan pengujian dengan metode 1.1-diphenyl-2-picrylhydrazyl (DPPH), dan kadar toksisitas yakni nilai Lethality Concetration 50 (LC50) sebesar 602 μg/mL yang dilakukan dengan metode pengujian Brine Shrimp Lethality Test (BSLT). Kata kunci: Pinang Yaki, Antioksidan, Toksisitas, DPPH, BSLT