Enumerasi Total Populasi Mikroba Tanah Gambut Di Teluk Meranti Kabupaten Riau

Teluk Meranti is one of the peatland area in Riau province. Most of these lands have beenchanged into palm oil plantation, timber plantation, agricultural area and settlement. Theaim of this research was to analyze the impact of land use changes on soil physical-chemical characteristics and microbial cell number. Soil samples were taken from eightdifferent locations, namely primary forest as control, secondary forest, rubber plantation(15 monthsyears old), rubber forest (40-60 years old), palm oil plantation (7-8 years old),acacia plantation (2-3 years old), corn field, and cassava field. Microbial cell number wasdetermined by spread plate method, employing appropriate media for the growth ofbacteria, fungi and actinomycetes. The results showed that the soil humidity, soiltemperature, percentage of soil dry weight, water content, soil bulk density and pH rangedfrom 29,63-55,88%, 27-31,5 o C, 14,9-35,5%, 64,9-85,1%, 0,16-0,39 g/cm 3 and 3,63-4,00,respectively. The copiotrophic bacterial cell number ranged from 0,6x10 5 -1,8x10 5 CFU/gsoil where the highest population was at the palm oil plantation,whereas the oligotrophicbacterial cell number ranged from 0,5x10 5 -1,4x10 5 CFU/g soil where the highest populationwas at the palm oil plantation. The population of fungi ranged from 0,4x10 5 -1,0x10 5 CFU/gsoil where the highest population was at the corn field. The population of actinomycetesranged from 0,4x10 5 -10,7x10 5 CFU/g soil where the highest population was at the palm oilplantation. Land use changes caused microbial cell number increased. The results indicatedthat land use changes influenced the microbial cell numbers

Synthesis of pH-Responsive Inorganic Janus Nanoparticles and Experimental Investigation of the Stability of Their Pickering Emulsions

Pickering emulsions exhibit outstanding stability, especially those prepared with Janus particles, whose desorption energy is expected to be up to 3-fold greater than emulsions of homogeneous particles from theoretical calculations. To the best of our knowledge, however, there remains no experimental proof of this behavior in practice. In this study, inorganic Janus nanoparticles were fabricated by regioselective modification of the separate side of SiO₂ nanoparticles with a judiciously selected mixture of trimethoxysilylpropyldiethylenetriamine and <i>n</i>-octyltrimethoxysilane. Janus nanoparticles demonstrated excellent interfacial activity, forming Pickering emulsions with oil phases at oil–water interfacial tensions ranging from 6.6–52.8 mN m^–1. Furthermore, as the interface of the Janus nanoparticles was regionally functionalized with −NH₂ groups, phase inversion could be realized by tuning pH. This is the first example for the Pickering emulsions stabilized with inorganic Janus particles. Importantly, based on the results of centrifugation experiment, the desorption energy of Janus nanoparticles at the interface was 3.2 times larger than that of homogeneous nanoparticles, which is in accordance with the result from theoretical calculations. These experimental results will substantially enrich our understanding of Janus nanoparticle Pickering emulsions and their interfacial assembly behavior

Aboveground biomass in different patches within heterogeneous soil

Aboveground biomass in different patches within heterogeneous soi

Aboveground biomass in pure soils

Aboveground biomass in pure soil

From Nonporous to Porous Doubly-Pillared-Layer Framework: Control over Interpenetration via Shape Alteration of Layer Apertures

By introducing an amino substituent group on the dicarboxylate ligand, a porous doubly pillared-layer framework [Co₂(abdc)₂(bpy)₂]·8DMF (<b>2</b>; abdc = 2-amino-1,4-benzene dicarboxylate, bpy = 4,4′-bipyridine) has been obtained, which represents a shape/size modulation of the layer apertures to control over 2-fold interpenetration arising from the nonporous structure of [Co₂(bdc)₂(bpy)₂] (<b>1</b>; bdc = 1,4-benzene dicarboxylate). The bulk-phase purity, framework robustness and permanent porosity of <b>2</b> have been confirmed by powder X-ray diffraction, thermogravimetric analysis, and gas adsorption isotherms

Cell Penetrating Peptide-Based Redox-Sensitive Vaccine Delivery System for Subcutaneous Vaccination

In immunotherapy, induction of potent cellular immunity by vaccination is essential to treat intracellular infectious diseases and tumors. In this work, we designed a new synthetic peptide carrier, Cys-Trp-Trp-Arg₈-Cys-Arg₈-Cys-Arg₈-Cys, for vaccine delivery by integrating a redox-responsive disulfide bond cross-linking and cell-penetrating peptide arginine octamer. The carrier peptide bound to the antigen protein ovalbumin (OVA) via electrostatic self-assembly to form peptide/OVA nanocomposites. Then, the spontaneous oxidization of the thiols of the cysteine residues induced interpeptide disulfide bond cross-linking to construct denser peptide/OVA condensates. The cell-penetrating peptides incorporated in the carrier peptide could increase antigen uptake by antigen presenting cells. After being internalized by antigen presenting cells, the antigen could be rapidly released in cytoplasm along with degradation of the disulfide bonds by intracellular glutathione, which could promote potent CD8⁺ T cell immunity. The cross-linked peptide/OVA condensates were used for subcutaneous vaccination. The results showed that the peptide carrier mediated potent antigen-specific immune response by significantly increasing IgG titer; splenocyte proliferation; the secretion level of cytokines INF-γ, IL-12, IL-4, and IL-10; immune memory function, and the activation and maturation of dendritic cells. From the results, the low-molecular weight vaccine-condensing peptide with definite chemical composition could be developed as a novel class of vaccine delivery systems

Tumor-Penetrating Peptide-Functionalized Redox-Responsive Hyperbranched Poly(amido amine) Delivering siRNA for Lung Cancer Therapy

Biosafety and the targeting ability of gene delivery systems are critical aspects for gene therapy of cancer. In this study, we report the synthesis and use of redox-responsive poly­(amido amine) (PAA) with good biocompatibility and biodegradation as a gene carrier material. A tumor-specific tissue penetration peptide, internalizing-RGD (iRGD) was then conjugated to PAA with an amidation reaction. In experiments using H1299 cells, PAA-iRGD was found to have a lower cytotoxicity and higher cellular uptake efficiency compared to PAA. An siRNA, specific to epidermal growth factor receptor (EGFR) that is overexpressed on the lung cancer cell surface and often targeted in lung cancer treatment, was designed to silence EGFR (i.e., siEGFR) for delivery by the gene carrier PAA-iRGD. <i>EGFR</i> gene silencing, apoptosis, antiproliferation, and antitumor effects of PAA-iRGD/siEGFR were evaluated <i>in vitro</i> and <i>in vivo</i>. PAA-iRGD/siEGFR displayed a much higher gene silencing ability compared to PAA and polyethylenimine (25 kDa), significantly inhibited the proliferation and migration of H1299 cells, and elicited significant cell apoptosis. Moreover, intravenously injected PAA-iRGD/siEGFR inhibited lung tumor growth <i>in vivo</i>. These results suggest that PAA-iRGD with good biocompatibility, biodegradation, and targeting ability could be a promising gene delivery system for gene therapy of cancers

Self-Assembly of Single-Virus SERS Hotspots for Highly Sensitive <i>In Situ</i> Detection of SARS-CoV‑2 on Solid Surfaces

Microbial surface transmission has aroused great attention since the pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Developing a simple in situ detection method for viruses on solid surfaces is of great significance for timely public health surveillance. Taking advantage of the natural structure of SARS-CoV-2, we reported the assembly of Au@AgNPs on the surface of a single virus by the specific aptamer–spike protein interaction. Multiple hotspots can be created between the neighboring Au@AgNPs for the highly sensitive surface-enhanced Raman scattering (SERS) detection of SARS-CoV-2. Using two different aptamers labeled with Cy3 and Au@AgNPs, in situ SERS detection of pseudotyped SARS-CoV-2 (PSV) on packaging surfaces was achieved within 20 min, with a detection limit of 5.26 TCID50/mL. For the blind testing of 20 PSV-contaminated packaging samples, this SERS aptasensor had a sensitivity of 100% and an accuracy of 100%. This assay has been successfully applied to in situ detection of PSV on the surfaces of different packaging materials, suggesting its potential applicability

Combined Chemo-photothermal Antitumor Therapy Using Molybdenum Disulfide Modified with Hyperbranched Polyglycidyl

In the treatment of cancers, molybdenum disulfide (MoS₂) has shown great potential as a photoabsorbing agent in photothermal therapy and also as an antitumor drug delivery system in chemotherapy. However, the poor dispersibility and stability of MoS₂ in aqueous solutions limit its applications in cancer therapy. To overcome the shortcomings, MoS₂ was modified mainly by surface adsorption of linear polymers, such as chitosan and poly­(ethylene glycol). As reported, the linear polymers could be more rapidly cleared from blood circulation than their branched counterparts. Herein, we developed hyperbranched polyglycidyl (HPG)-modified MoS₂ (MoS₂–HPG) by absorbing HPG on the MoS₂ surface. The MoS₂–HPG as a novel photoabsorbing agent was also used as a nanoscaled carrier to load antitumor drug doxorubicin hydrochloride (DOX) (MoS₂–HPG–DOX) for combined chemo-photothermal therapy. The physicochemical and photothermal properties of MoS₂–HPG were measured, and the results indicate that MoS₂–HPG had good dispersion and stability in aqueous solutions and also high photothermal conversion efficiency. MoS₂–HPG displayed good biocompatibility in hemocompatibility and cytotoxicity evaluations in vitro. Furthermore, the combined chemo-photothermal therapy using MoS₂–HPG–DOX demonstrated better anticancer effect than the individual chemotherapy or photothermal therapy alone. From the results, MoS₂–HPG with combined chemo-photothermal therapy could be developed as a promising therapeutic formulation for clinical cancer treatment

Polyethylenimine-Induced Alterations of Red Blood Cells and Their Recognition by the Complement System and Macrophages

In practical applications, biomedical materials introduced in vivo may interact with various host cells and/or biomacromolecules and alter their physiological characteristics. Biomaterial-altered cells and/or biomacromolecules may be recognized as “non-self” by the host immune system and may consequently cause further immune responses. In the present work, the gene carrier material branched polyethylenimine (1.8 kDa) (BPEI-1.8k) induced a series of alterations of human red blood cells (RBCs), such as a morphological transition from biconcave disks to spheroechinocytes, vesiculation, a size decrease, a change in surface charge from negative to positive, a cell density reduction, membrane oxidation, and PS externalization. Furthermore, BPEI-1.8k-treated RBCs caused autologous complement activation and were recognized by autologous macrophages. This implies that the biomedical material BPEI-1.8k changed the identity of the RBCs, leading to their recognition by the autologous immune system. This study provides novel insights for the biocompatibility evaluation and clinical application of biomedical materials