Characterization of an Insoluble and Soluble Form of Melanin Produced by Streptomyces cavourensis SV 21, a Sea Cucumber Associated Bacterium

Melanin is a widely distributed and striking dark-colored pigment produced by countless living organisms. Although a wide range of bioactivities have been recognized, there are still major constraints in using melanin for biotechnological applications such as its fragmentary known chemical structure and its insolubility in inorganic and organic solvents. In this study, a bacterial culture of Streptomyces cavourensis SV 21 produced two distinct forms of melanin: (1) a particulate, insoluble form as well as (2) a rarely observed water-soluble form. The here presented novel, acid-free purification protocol of purified particulate melanin (PPM) and purified dissolved melanin (PDM) represents the basis for an in-depth comparison of their physicochemical and biological properties, which were compared to the traditional acid-based precipitation of melanin (AM) and to a synthetic melanin standard (SM). Our data show that the differences in solubility between PDM and PPM in aqueous solutions may be a result of different adjoining cation species, since the soluble PDM polymer is largely composed of Mg2+ ions and the insoluble PPM is dominated by Ca2+ ions. Furthermore, AM shared most properties with SM, which is likely attributed to a similar, acid-based production protocol. The here presented gentler approach of purifying melanin facilitates a new perspective of an intact form of soluble and insoluble melanin that is less chemical altered and thus closer to its original biological form.

Enhancing Uptake of K and Zn and Improving Yield of Groundnut by Application of K- and Zn- Solubilizing Bacteria

Background: Potassium and zinc are important with respect to mineral nutrition of groundnut and play a significant role in physiological and biochemical processes and thus affect productivity. To make these important minerals available to the growing plants in calcareous soil having fixation problem, the current investigation was undertaken to identify both K- and Zn-solubilizing bacteria for improving growth, nutrient uptake and yield of groundnut. Methods: Soil samples were collected from groundnut rhizosphere during 2018 for the isolation of Zn- and K- solubilizing bacteria. Estimation for Zn- and K-solubilization was done using zinc phosphate and potassium aluminosilicate as insoluble form of Zn and K, respectively. Promising Zn and K solubilizing bacterial isolates were selected and evaluated in pots. Result: Inoculation of different isolates of KSB and ZSB improved K and Zn contents of shoot and seed during summer and kharif 2019. Evaluation of KSB and ZSB isolates, in potted condition, resulted in improved pod yield upto 39.6% (KSB) and upto 37.1% (ZSB) during summer and upto 24.1% and 25.1% during kharif 2019, respectively. Therefore, uptake of Zn- and K- and yield of groundnut can be enhanced significantly by application of both potential ZSB and KSB.

A Method of Solubilizing and Concentrating Astaxanthin and Other Carotenoids

The valuable marine carotenoid, astaxanthin, is used in supplements, medicines and cosmetics. In this study, crustacyanin, an astaxanthin-binding protein, was used to solubilize and concentrate astaxanthin. The recombinant crustacyanin of European lobster spontaneously formed an inclusion body when it was over-expressed in Escherichia coli. In this study, fusing the NusA-tag to the crustacyanin subunits made it possible to express in a soluble fraction and solubilize astaxanthin in aqueous solution. By cutting off the NusA-tag, the crustacyanin subunits generated the pure insoluble form, and captured and concentrated astaxanthin. Overall, the attaching and releasing NusA-tag method has the potential to supply solubilized carotenoids in aqueous solution and concentrated carotenoids, respectively.

PENGARUH APLIKASI BAKTERI PELARUT FOSFAT DAN PUPUK ANORGANIK FOSFAT TERHADAP POPULASI BAKTERI PELARUT FOSFAT, P-TERSEDIA, DAN HASIL TANAMAN JAGUNG PADA ALFISOL

Fulfilment of nutrients for plants can be maximized when fertilization, but the application of inorganic fertilizers can cause damage to the soil if the dosage is excessive. The utilization of phosphate solubilizing bacteria is an effort to increase the efficiency of phosphate fertilization that can extract phosphate from an insoluble form that becomes available. This study aimed to obtain a combination of inorganic fertilization doses (SP-36 and NPK) and the application of biological fertilizers that utilize phosphate solubilizing bacteria (PSB) to increase the population of phosphate solubilizing bacteria and P-available in the soil, as well as corn crop yields. This study used a randomized block design with nine treatments and three replications. The result showed that the application of PSB and inorganic phosphate fertilizer shows a significant effect on the population of PSB, P-available, plant height, stover dry weight, cob weight with husk and cob weight without husk, but didn’t show a significant effect on 100 seeds weight and number of plant leaves. Based on the correlation analysis, the results show a positive correlation between soil chemical properties, P-available, and corn yield.

Influence of Glycerophosphate Salt Solubility on the Gelation Mechanism of Colloidal Chitosan Systems

Recently, thermosensitive chitosan systems have attracted the interest of many researchers due to their growing application potential. Nevertheless, the mechanism of the sol-gel phase transition is still being discussed, and the glycerophosphate salt role is ambiguous. The aim of the work is to analyze the possibility of the exclusive use of a non-sodium glycerophosphate salt and to determine its impact on the gelation conditions determined by rheological and turbidimetric measurements as well as the stability of the systems by measuring changes in the Zeta potential value. It was found that ensuring the same proportions of glycerophosphate ions differing in cation to amino groups present in chitosan chains, leads to obtaining systems significantly different in viscoelastic properties and phase transition conditions. It was clearly shown that the systems with the calcium glycerophosphate, the insoluble form of which may constitute additional aggregation nuclei, undergo the gelation the fastest. The use of magnesium glycerophosphate salt delays the gelation due to the heat-induced dissolution of the salt. Thus, it was unequivocally demonstrated that the formulation of the gelation mechanism of thermosensitive chitosan systems based solely on the concentration of glycerophosphate without discussing its type is incorrect.

Purification of recombinant human interleukin-3 expressed as inclusion bodies in Escherichi coli

Human interleukin-3 (IL-3) is a hematopoietic growth factor involved in the survival, proliferation and differentiation of multipotent hematopoietic cells. However, recombinant IL-3 is usually expressed as insoluble form (inclusion bodies) in Escherichia coli cells. This state of protein often shows no bioactivity. Herein, we report a simple method for solubilization, refolding and purification of recombinant human IL-3 expressed in E. coli cells. First, IL-3 was expressed in E. coli JM109 (DE3) after being induced with 0.05 mM IPTG at 25 oC. Under these conditions, IL-3 was produced as inclusion bodies with molecular weight of approximately 15 kDa on SDS-PAGE gel (14%). Next, IL-3 pellet was separated from the host soluble proteins using sonication followed centrifugation. Then, two strong denaturants such as urea or guanidine hydrochloride were used to test solubilization of the insoluble IL-3. After that, the resulting soluble IL-3 was renatured and subjected to gel filtration chromatography to collect purified IL-3 protein. Our results showed that fractionates contained a single band of IL-3 with recovery rate of about 30%. Several characteristics of recombinant IL-3 were then analyzed. The cytokine IL-3 showed its high purity with a sharp peak on RP-HPLC chromatagram. The Western blot showed a clear signal band on PVDF membrane to demonstrate its right antigenecity against human IL-3 antibody. Besides, amino acid sequence of this cytokine was confirmed by mass spectrophotometry method. The purified IL-3 cytokine is a potential material for further tests.

Prussian Blue: A Safe Pigment with Zeolitic-Like Activity

Prussian blue (PB) and PB analogues (PBA) are coordination network materials that present important similarities with zeolites concretely with their ability of adsorbing cations. Depending on the conditions of preparation, which is cheap and easy, PB can be classified into soluble PB and insoluble PB. The zeolitic-like properties are mainly inherent to insoluble form. This form presents some defects in its cubic lattice resulting in an open structure. The vacancies make PB capable of taking up and trapping ions or molecules into the lattice. Important adsorption characteristics of PB are a high specific area (370 m2 g−1 determined according the BET theory), uniform pore diameter, and large pore width. PB has numerous applications in many scientific and technological fields. PB are assembled into nanoparticles that, due to their biosafety and biocompatibility, can be used for biomedical applications. PB and PBA have been shown to be excellent sorbents of radioactive cesium and radioactive and nonradioactive thallium. Other cations adsorbed by PB are K+, Na+, NH4+, and some divalent cations. PB can also capture gaseous molecules, hydrocarbons, and even luminescent molecules such as 2-aminoanthracene. As the main adsorptive application of PB is the selective removal of cations from the environment, it is important to easily separate the sorbent of the purified solution. To facilitate this, PB is encapsulated into a polymer or coats a support, sometimes magnetic particles. Finally, is remarkable to point out that PB can be recycled and the adsorbed material can be recovered.

Expression and Isolation of N-Terminal Truncated Human Recombinant Renalase in Prokaryotic Cells

Renalase (RNLS) is a flavoproteinin which its N-terminal peptide (residues 1-17) has several important functions. In cells, it participates in the formation of the so-called Rossmanfold (residues 2-35), needed for «accommodation» of the FAD cofactor and for performing the catalytic functions of RNLS as a FAD-dependent oxidoreductase (EC 1.6.3.5). RNLS secretion into the extracellular space is accompanied by cleavage of this peptide. The resultant truncated extracellular RNLS cannot bind FAD and therefore performs various noncatalytic functions. In this work, we have performed expression the genetic construct encoding RNLS lacking its N-terminal signal peptide (tRNLS) in E. coli Rosetta (DE3) cells. The recombinant protein was accumulated in inclusion bodies in an insoluble form, which could be solubilized in the presence of a high concentration of urea or guanidine chloride. In contrast to full-length RNLS, which was effectively solubilized in the presence of 8 M urea, tRNLS was preferentially solubilized in the presence of 6 M guanidine chloride.

Cloning and expression of Neospora caninum rhoptry 2 and its potential as an immunobiological for neosporosis control

ABSTRACT: The protozoan Neospora caninum is known worldwide as one of the main causes of abortion in cattle. During infection, rhoptry proteins present in the apical complex of the parasite play important roles in adhesion and parasitophorous vacuole formation. The use of N. caninum ROP2 in experimental vaccines has shown promising protective results. In our study we performed cloning and expression in Escherichia coli of an antigenic portion of N. caninum ROP2. The recombinant protein (rROP2) was obtained in insoluble form, and the purified protein showed a size of approximately 18kDa. Even being a small truncate NcROP2 region, it was possible to conserve the antigenic epitopes which were recognized by bovine serum naturally infected with N. caninum. Vaccination with rROP2 on aluminum hydroxide adjuvant induced high levels of rROP2-specific IgG antibodies capable of recognizing native protein in tachyzoite lysates. In conclusion, our approaches were effective in obtaining the rROP2 protein, which induced specific mouse immune response and was also recognized by sera from N. caninum naturally infected cattle. These results suggest that it is a promising antigen for the development of neosporosis subunit vaccines as well as a suitable antigen for use in immunodiagnosis.

Changes in Feed Proanthocyanidin Profiles during Silage Production and Digestion by Lamb

Proanthocyanidins are plant specialized metabolites which are beneficial to animal nutrition and health. This study determined how proanthocyanidin profiles of sainfoin (Onobrychis viciifolia) and birdsfoot trefoil (Lotus corniculatus) change during the forage conservation process and along the digestive tract of lamb. We determined soluble, protein- and fiber-bound proanthocyanidins by spectrophotometric methods and soluble proanthocyanidin profiles by UPLC-MS/MS. During the conservation process, the total proanthocyanidin contents reduced in both forages and the relative proportion of insoluble proanthocyanidins increased, especially in sainfoin. The soluble proanthocyanidins, their mean degree of polymerization and the relative prodelphinidin share declined in both feed species. In the abomasum of lambs fed sainfoin silage, most of the proanthocyanidins were in insoluble form bound to proteins and fibers, but in the small and large intestines, the proportion of soluble proanthocyanidins increased again. For lambs fed birdsfoot trefoil, the trend was not so clear as proanthocyanidins were already mainly soluble in the abomasum. Nevertheless, a large part of soluble proanthocyanidins was recovered in the digestive tract but could not be detected by the UPLC-MS/MS method used. This study suggests that proanthocyanidins have probably been metabolized in the digestive tract by the resident microbiota.