Oligochitosan Synthesized by Cunninghamella elegans, a Fungus from Caatinga (The Brazilian Savanna) Is a Better Antioxidant than Animal Chitosan

Animal chitosan (Chit-A) is gaining more acceptance in daily activities. It is used in a range of products from food supplements for weight loss to even raw materials for producing nanoparticles and hydrogel drug carriers; however, it has low antioxidant activity. Fungal oligochitosan (OChit-F) was identified as a potential substitute for Chit-A. Cunninghamella elegans is a fungus found in the Brazilian savanna (Caatinga) that produces OligoChit-F, which is a relatively poorly studied compound. In this study, 4 kDa OChit-F with a 76% deacetylation degree was extracted from C. elegans. OChit-F showed antioxidant activity similar to that of Chit-A in only one in vitro test (copper chelation) but exhibited higher activity than that of Chit-A in three other tests (reducing power, hydroxyl radical scavenging, and iron chelation). These results indicate that OChit-F is a better antioxidant than Chit-A. In addition, Chit-A significantly increased the formation of calcium oxalate crystals in vitro, particularly those of the monohydrate (COM) type; however, OChit-F had no effect on this process in vitro. In summary, OChit-F had higher antioxidant activity than Chit-A and did not induce the formation of CaOx crystals. Thus, OChit-F can be used as a Chit-A substitute in applications affected by oxidative stress.

Evaluation of the antioxidant activity from bovine serum albumin protein fractions

Objective: Evaluate the antioxidant activity of protein fractions obtained from (bovine serum albumin) BSA protein hydrolysates. Design / methodology / approach: Bioinformatics tools, such as the NCBI database, were used to search for primary sequences of BSA proteins. The methodology included a prediction of peptides with antioxidant activity through various bioinformatics servers. The antioxidant activity was determined by different methods. Statistical analysis was performed to evaluate possible significant differences using the Student Newman Keulls test for group comparison. Results: Through in silica hydrolysis the following peptides were found: valine-alanine-phenylalanine (VAF), lysine-tryptophan (KW), phenylalanine-tyrosine (FY), alanine-proline (AP), among others that may have antioxidant activity. The results showed that the fraction <1 kDa hydrolyzed with chymotrypsin, this fraction showed 84% copper chelation, 61% iron chelation, while 75% inhibition of the DPPH radical. In the case of the fraction <1 kDa hydrolyzed with pepsin, it only showed 16% iron chelation, while in the other methods no value was detected. Study limitations / implications: The enzyme used for enzymatic hydrolysis generates low degrees of hydrolysis and generates oligopeptide dipeptides that may not be as like some of the tested methods, in addition to the protein concentration in the fraction <1 kDa with pepsin it had very low values that could not be detected by some antioxidant methods. Findings / conclusions: The antioxidant activity of the <1 kDa fraction obtained with chymotrypsin showed greater antioxidant and chelating activity, compared to the <1 kDa fraction obtained with pepsin. However, at the concentration of 2% and 5% fluctuations are observed in both fractions, because probably the composition of amino acids that is present in both fractions determines the activity in each of the tested methods

Insight Into the Role of PGPR in Sustainable Agriculture and Environment

A multitude of roles is played by microbes in food and agriculture that include nutrient cycling and management, organic matter decomposition and fermentation. Plant growth promoting rhizobacteria (PGPR), representing microbial groups and with ability of colonizing plant roots, influence plant growth through various indirect and direct modes in order to promote its growth and/or protect it from diseases or damage due to insect attack. Thus, PGPR research has received renewed interest worldwide. Increasing number of crop-specific PGPR are being commercialized these days. Approaches like seed-inoculation and soil application either alone or in combination with bacterial culture/product for increased nutrient availability through phosphate solubilisation, potassium solubilisation, sulfur oxidation, nitrogen fixation, iron, and copper chelation are gaining popularity. Arbuscular mycorrhizal fungi (AMF) are root fungal symbiont that improve management of abiotic stress such as phosphorus deficiency. PGPR involves roles like production of indole acetic acid (IAA), ammonia (NH3), hydrogen cyanide (HCN), catalase, etc. PGPR also improve nutrient uptake by altering the level of plant hormone that enhances root surface area by increasing its girth and shape, thereby helping in absorbing more nutrients. PGPR facilitate seed germination, seedling growth and crop yield. An array of microbes including Pseudomonas, Azospirillum, Azotobacter, Klebsiella, Enterobacter, Alcaligenes, Arthrobacter, Burkholderia, Bacillus, and Serratia enhance plant growth. Various Pseudomonas sp. have demonstrated significant increase in germination, seedling growth and yield in different agricultural crops, including wheat. Hence, developing a successful crop-specific PGPR formulation, the candidate should possess characteristics like high rhizosphere competence, extensive competitive saprophytic ability, growth enhancing ability, ease of mass production, broad-spectrum action, safety toward the environment and compatibility with other partnering organisms.

Mosquito metallomics reveal copper and iron as critical factors for Plasmodium infection

Iron and copper chelation restricts Plasmodium growth in vitro and in mammalian hosts. The parasite alters metal homeostasis in red blood cells to its favor, for example metabolizing hemoglobin to hemozoin. Metal interactions with the mosquito have not, however, been studied. Here, we describe the metallomes of Anopheles albimanus and Aedes aegypti throughout their life cycle and following a blood meal. Consistent with previous reports, we found evidence of maternal iron deposition in embryos of Ae. aegypti, but less so in An. albimanus. Sodium, potassium, iron, and copper are present at higher concentrations during larval developmental stages. Two An. albimanus phenotypes that differ in their susceptibility to Plasmodium berghei infection were studied. The susceptible white stripe (ws) phenotype was named after a dorsal white stripe apparent during larval stages 3, 4, and pupae. During larval stage 3, ws larvae accumulate more iron and copper than the resistant brown stripe (bs) phenotype counterparts. A similar increase in copper and iron accumulation was also observed in the susceptible ws, but not in the resistant bs phenotype following P. berghei infection. Feeding ws mosquitoes with extracellular iron and copper chelators before and after receiving Plasmodium-infected blood protected from infection and simultaneously affected follicular development in the case of iron chelation. Unexpectedly, the application of the iron chelator to the bs strain reverted resistance to infection. Besides a drop in iron, iron-chelated bs mosquitoes experienced a concomitant loss of copper. Thus, the effect of metal chelation on P. berghei infectivity was strain-specific.

Hypopituitarism in Wilson’s disease resolved after copper-chelating therapy

Summary Wilson’s disease (WD) is a rare disorder of copper metabolism usually presenting with variable liver damage and neuropsychiatric symptoms. Here we report a 39-year-old Taiwanese female with late manifestation of WD presenting with gonadotroph, thyreotroph and corticotroph hypopituitarism. Molecular genetic testing revealed compound heterozygosity for two mutations in exons 12 and 14 (c.2828G>A and c.3140A>T). Copper-chelating therapy with D-penicillamine and zinc was initiated along with supplementation of hydrocortisone and L-thyroxine. Hypopituitarism resolved when urinary copper excretion returned to normal levels under copper chelation. This case should raise awareness of pituitary function in WD patients. Learning points Hypopituitarism can complicate Wilson’s disease (WD) and endocrinologists should be aware of it when caring for hypopituitary patients. Hepatologists should consider endocrinologic testing for hypopituitarism when WD patients present with symptoms of adrenal insufficiency, thyroid or gonadal dysfunction. Copper-chelating treatment is mandatory and may lead to the recovery of pituitary function in such patients.

Antioxidant activity, inhibition of angiotensin I converting enzyme (ACE) and antibacterial activity of buffalo caseinate protein hydrolysates and their fractions

In the present study, buffalo milk caseinate hydrolysates produced by bromelain, neutrase, papain and trypsin were ultra-filtered and different fractions were assessed for antioxidant, inhibition of angiotensin converting enzyme and antimicrobial activity. Biological potential was assessed by a number of metrics: ability to remove radicals of 2,2'-azino-bis (3-ethylbenzthiazoline-6-sulfonic acid), 2,2'-diphenyl-1-picrylhydrazyl (DPPH) and hydroxyls; copper and iron chelation; antidiabetic properties; antihypertensive assay; and antibacterial activity against Escherichia coli ATCC 25922, Listeria monocytogenes ATCC 19114, Salmonella typhimurium ATCC 14028 and Staphylococcus aureus ATCC 25923 strains. The tests for scavenging of hydroxyl radicals and DPPH revealed a greater potential in the 3–10 kDa fractions. Iron chelation activity >70% was observed in all the fractions, including <3 kDa. Copper chelation was >60% in fractions >10 kDa. α-Amylase inhibition and antihypertensive activity was optimal in the <3 kDa fraction. Antibacterial activity ranged between 3.28 and 100% inhibition against microorganisms tested, the fraction <3 kDa showed a greater inhibitory potential. The antihypertensive activity of fractions ranged between 39.35 and 89.58%. All treatments were able to produce hydrolysates and fractions with biological potential and, so the ultrafiltration method proved to be effective in the separation of peptides with different molar masses and potential use in the food or pharmaceutical industry.

Retromer retrieves the Wilson disease protein ATP7B from endolysosomes in a copper-dependent manner

ABSTRACTThe Wilson disease protein, ATP7B maintains copper (herein referring to the Cu+ ion) homeostasis in the liver. ATP7B traffics from trans-Golgi network to endolysosomes to export excess copper. Regulation of ATP7B trafficking to and from endolysosomes is not well understood. We investigated the fate of ATP7B after copper export. At high copper levels, ATP7B traffics primarily to acidic, active hydrolase (cathepsin-B)-positive endolysosomes and, upon subsequent copper chelation, returns to the trans-Golgi network (TGN). At high copper, ATP7B colocalizes with endolysosomal markers and with a core member of retromer complex, VPS35. Knocking down VPS35 did not abrogate the copper export function of ATP7B or its copper-responsive anterograde trafficking to vesicles; rather upon subsequent copper chelation, ATP7B failed to relocalize to the TGN, which was rescued by overexpressing wild-type VPS35. Overexpressing mutants of the retromer complex-associated proteins Rab7A and COMMD1 yielded a similar non-recycling phenotype of ATP7B. At high copper, VPS35 and ATP7B are juxtaposed on the same endolysosome and form a large complex that is stabilized by in vivo photoamino acid labeling and UV-crosslinking. We demonstrate that retromer regulates endolysosome to TGN trafficking of copper transporter ATP7B in a manner that is dependent upon intracellular copper.