Acute and subchronic effects of petroleum on the freshwater fish Hoplias aff. malabaricus

Petroleum water soluble fraction (WSF) impairs organisms, but damages may vary among cell and tissue levels. The aim of the present study was to evaluate the acute (24 h, 48 h, 72 h) and subchronic effects (36 days) of WSF (0%, 25% and 100%) in juveniles of the Neotropical top predator fish Hoplias aff. malabaricus. The effects of WSF were evaluated at a molecular level using the comet assay and micronucleus test for genome damage; and at a morphological level through histological identification of liver pathologic lesions. In both acute and subchronic exposure we found low levels of DNA damage (< 10% of comet tail) and non-significant frequency of micronucleus in WSF exposed fish. The most significant liver lesions in WSF exposed fish were fatty vacuolization, hypertrophy and focal necrosis. Since these tissue injuries were progressive and persistent, their irreversibility may negatively affect fish recruitment, even in a such resistant top predator.

Changes in chemical composition of cover crops residue during decomposition

ABSTRACT: Crop residues decomposition are controlled by chemical tissue components. This study evaluated changes on plant tissue components, separated by the Van Soest partitioning method, during cover crop decomposition. The Van Soest soluble fraction was the first to be released from the crop residues, followed by cellulose and hemicellulose. Lignin was the crop residue component that suffered the least degradation, and for certain crop residue types, lignin degradation was not detected. The degradation of the main components of crop residues (soluble fraction, cellulose, hemicellulose and lignin) is determined by the chemical and structural composition of each fraction.

Glycolytic flux-signaling controls mouse embryo mesoderm development

How cellular metabolic state impacts cellular programs is a fundamental, unresolved question. Here we investigated how glycolytic flux impacts embryonic development, using presomitic mesoderm (PSM) patterning as the experimental model. First, we identified fructose 1,6-bisphosphate (FBP) as an in vivo sentinel metabolite that mirrors glycolytic flux within PSM cells of post-implantation mouse embryos. We found that medium-supplementation with FBP, but not with other glycolytic metabolites, such as fructose 6-phosphate and 3-phosphoglycerate, impaired mesoderm segmentation. To genetically manipulate glycolytic flux and FBP levels, we generated a mouse model enabling the conditional overexpression of dominant active, cytoplasmic Pfkfb3 (cytoPfkfb3). Overexpression of cytoPfkfb3 indeed led to increased glycolytic flux/FBP levels and caused an impairment of mesoderm segmentation, paralleled by the downregulation of Wnt-signaling, reminiscent of the effects seen upon FBP-supplementation. To probe for mechanisms underlying glycolytic flux-signaling, we performed subcellular proteome analysis and revealed that cytoPfkfb3 overexpression altered subcellular localization of certain proteins, including glycolytic enzymes, in PSM cells. Specifically, we revealed that FBP supplementation caused depletion of Pfkl and Aldoa from the nuclear-soluble fraction. Combined, we propose that FBP functions as a flux-signaling metabolite connecting glycolysis and PSM patterning, potentially through modulating subcellular protein localization.

Modifikasi Medium Menggunakan Saline-Water Soluble Fraction (SSF) atau Fraksi Minyak Terlarut untuk Menumbuhkan Bakteri Pendegradasi Hidrokarbon

Isolasi bakteri pendegradasi hidrokarbon memerlukan teknik yang baik dan nutrisi optimal untuk pertumbuhannya. Kendala dalam pembuatan medium dan pengamatan isolat bakteri yang mengandung hidrokarbon sering terjadi di laboratorium, sehingga dibutuhkan teknik pengembangan metode dalam proses isolasi bakteri pendegradasi hidrokarbon. Penelitian ini bertujuan untuk mengetahui dan membandingkan jumlah dan jenis koloni bakteri yang tumbuh dalam medium Zobell+saline-water soluble fraction (SSF) dibandingkan dengan medium Zobell+minyak bumi. Metode penelitian yaitu mengisolasi bakteri menggunakan medium Zobell+SSF 6 jam (A), 12 jam (B), 24 jam (C) dan sebagai kontrol adalah medium Zobell+1% v/v minyak bumi (K), perhitungan bakteri menggunakan metode TPC dan mengidentifikasi bakteri dengan alat VITEK-MS. Hasil penelitian memperlihatkan bahwa jumlah bakteri yang tumbuh pada medium Zobell+SSF 24 jam (C) adalah 6.9 x 108 CFU/ml, hal ini menunjukkan lebih baik dibandingkan dengan Zobell+1% v/v minyak bumi (K)=5.2 x 108 CFU/ml, medium Zobell+SSF 12 jam (B)=6.6 x 107 CFU/ml dan medium Zobell+SSF 6 jam (A)=1.8 x 107 CFU/ml.Kesimpulan penelitian ini adalah bahwa dari segi jumlah total bakteri medium modifikasi Zobell+SSF pengadukan selama 24 jam (C) lebih baik dalam menumbuhkan bakteri pendegradasi hidrokarbon dibandingkan dengan pengadukan 6 jam (A), 12 jam (B), dan medium Zobell+1% v/v minyak bumi (K). Sedangkan apabila berdasarkan dengan keragaman bakteri, didapatkan hasil bahwa strain bakteri yang terisolasi pada medium modifikasi Zobell+SSF perlakuan pengadukan 6, 12, 24 jam sama dengan strain bakteri yang tumbuh pada kontrol (medium Zobell +1% v/v minyak bumi. Bakteri yang teridentifikasi sebagai bakteri pendegaradsi hidrokarbon adalah bakteri Klebsiella pneumoniae, Enterobacter asburiae/Enterobacter cloacae dan Pseudomonas aeruginosa.

Oxidation Characteristics of Water Soluble Fractions of Agro-Stalks with Focus on Function of Reactive Inorganics

In order to deepen the understanding of the thermochemical behavior of reactive inorganics, which play an important role in slagging and fouling during combustion of agro-stalks, the oxidation behavior of the water-soluble fraction of corn stover, wheat straw and rice straw was examined using a simultaneous thermogravimetric analyzer. The oxidation characteristics were discussed in combination with elemental analysis of water-soluble fractions. Results showed that reactive inorganics elements account for 30–40% in water-soluble fractions of the three agro-stalks and carbon was oxidized at two separate stages. Four stages were found during oxidation of water-soluble fractions – (1) devolatilisation of organics (100‒400 °C); (2) oxidation of char (400–650 °C); (3) oxidation of char with melting of salts or decomposition of carbonate (650–800 °C); (4) vaporization of KCl (800–1000 °C). This work provides a base study for an optimized design of combustion for agro-stalks and pharmaceutical waste.