'Miracle tree' substance produces clean drinking water inexpensively and sustainably

Stephanie B. Velegol and colleagues explain that removing the disease-causing microbes and sediment from drinking water requires technology not always available in rural areas of developing countries. For an alternative approach, Velegol looked to Moringa oleifera, also called the "miracle tree," a plant grown in equatorial regions for food, traditional medicine and biofuel. Past research showed that a protein in Moringa seeds can clean water, but using the approach was too expensive and complicated. So Velegol's team sought to develop a simpler and less expensive way to utilize the seeds' power.

To do that, they added an extract of the seed containing the positively charged Moringa protein, which binds to sediment and kills microbes, to negatively charged sand. The resulting "functionalized," or "f-sand," proved effective in killing harmful E. coli bacteria and removing sediment from water samples. "The results open the possibility that ... f-sand can provide a simple, locally sustainable process for producing storable drinking water," the researchers say.

More information: Antimicrobial Sand via Adsorption of Cationic Moringa oleifera Protein, Langmuir, Article ASAP. DOI: 10.1021/la2038262

Abstract
Moringa oleifera (Moringa) seeds contain a natural cationic protein (MOCP) that can be used as an antimicrobial flocculant for water clarification. Currently, the main barrier to using Moringa seeds for producing potable water is that the seeds release other water-soluble proteins and organic matter, which increase the concentration of dissolved organic matter (DOM) in the water. The presence of this DOM supports the regrowth of pathogens in treated water, preventing its storage and later use. A new strategy has been established for retaining the MOCP protein and its ability to clarify and disinfect water while removing the excess organic matter. The MOCP is first adsorbed and immobilized onto sand granules, followed by a rinsing step wherein the excess organic matter is removed, thereby preventing later growth of bacteria in the purified water. Our hypotheses are that the protein remains adsorbed onto the sand after the functionalization treatment, and that the ability of the antimicrobial functionalized sand (f-sand) to clarify turbidity and kill bacteria, as MOCP does in bulk solution, is maintained. The data support these hypotheses, indicating that the f-sand removes silica microspheres and pathogens from water, renders adhered Escherichia coli bacteria nonviable, and reduces turbidity of a kaolin suspension. The antimicrobial properties of f-sand were assessed using fluorescent (live-dead) staining of bacteria on the surface of the f-sand. The DOM that can contribute to bacterial regrowth was shown to be significantly reduced in solution, by measuring biochemical oxygen demand (BOD). Overall, these results open the possibility that immobilization of the MOCP protein onto sand can provide a simple, locally sustainable process for producing storable drinking water.

Provided by American Chemical Society (news : web)

A substance from bacteria can lead to allergy-free sunscreen

"Unfortunately, several of the chemical UV filters used in sunscreens cause contact allergy, either of themselves or when they are exposed to sunlight. We have therefore studied a UV filter, scytonemin, that is found in certain bacteria. We have managed to produce this substance artificially in the laboratory", says Isabella Karlsson, research student in the Department of Chemistry at the University of Gothenburg.

Sunlight contains two types of UV radiation. The type known as "UVA" penetrates deeply into the skin and causes the pigment that we already have to darken. UVA, however, also causes the skin to age prematurely. The most common chemical UVA filter on the market is 4-tert-butyl-4'-methoxy dibenzoylmethane, BM-DBM, which is known to cause photocontact allergy when it reacts on the skin. Isabella Karlsson has shown that BM-DBM breaks down in UV light to form several different products. One of these, a group of substances known as "arylglyoxals", proved to be very potent contact allergens.

Isabella Karlsson also describes in her thesis studies of a relatively new UV filter, octocrylene. The popularity of octocrylene has increased a great deal since it is not broken down by sunlight, and it stabilises other substances such as, for example, BM-DBM. However, several reports of allergic reactions to octocrylene have appeared in recent years. Clinical studies and laboratory experiments have suggested that octocrylene can cause contact allergy, both of itself and when it is exposed to sunlight. Many patients who reacted by developing photocontact allergy to octocrylene developed photocontact allergy also to the drug ketoprofen.

"We tested 172 patients with suspected skin reactions to sunscreen creams and/or the drug ketoprofen in one of our studies. It turned out that 23 of these patients reacted to the UV filter octocrylene. Five of them were diagnosed with contact allergy and the other 18 with photocontact allergy."

So Isabella Karlsson is placing her hopes onto the natural product scytonemin. She has managed to produce this substance artificially, in collaboration with Chalmers University of Technology. Scytonemin is produced by certain cyanobacteria that live in habitats exposed to very strong sunlight. Scytonemin absorbs UV light and thus protects the bacteria from being damaged by the sun's radiation. More research will be required, however, before it can be added to sunscreen creams.

Provided by University of Gothenburg (news : web)

New substance may allow successful transplantation of 'marginal' livers

New research raises the possibility that the critically short supply of livers for organ donation could be expanded by treating so-called "marginal" livers with a substance that protects them from damage after being connected to recipients' blood supplies. The report appears in ACS' journal Molecular Pharmaceutics.

Ram Mahato and colleagues note that the need for liver transplants has grown over the years, though the number of available livers has not. Currently, more than 16,000 people are waiting for a liver in the U.S., but less than 7,000 liver transplants were performed during the entire year of 2010. This shortage has led organ transplant teams to consider using marginal, or damaged, livers, such as those with cholestasis — a build-up of bile. But transplanting a damaged liver has risks, including a higher risk that the organ will fail. To overcome this challenge, the researchers utilized a hedgehog-signaling inhibitor to increase the odds of a successful liver transplant.

They found that a compound called cyclopamine prevented further injury to cholestatic livers after the blood supply was cut off then returned — a situation similar to what transplanted livers undergo. The research was performed in rats, which are stand-ins for humans in the laboratory. It provided "convincing evidence" that cyclopamine may protect cholestatic livers from additional damage after a transplant procedure and improve clinical outcomes for the patients.

More information: “Cyclopamine attenuates acute warm ischemia reperfusion injury in cholestatic rat liver: Hope for marginal livers”, Mol. Pharmaceutics, Article ASAP DOI: 10.1021/mp200115v

Abstract
Cholestasis is a significant risk factor for immediate hepatic failure due to ischemia reperfusion (I/R) injury in patients undergoing liver surgery or transplantation. We recently demonstrated that inhibition of Hedgehog (Hh) signaling with cyclopamine (CYA) before I/R prevents liver injury. In this study we hypothesized that Hh signaling may modulate I/R injury in cholestatic rat liver. Cholestasis was induced by bile duct ligation (BDL). Seven days after BDL, rats were exposed to either CYA or vehicle for 7 days daily before being subjected to 30 min of ischemia and 4 h of reperfusion. Expression of Hh ligands (Sonic Hedgehog, Patched-1 and Glioblastoma-1), assessment of liver injury, neutrophil infiltration, cytokines, lipid peroxidation, cell proliferation and apoptosis were determined. Significant upregulation of Hh ligands was seen in vehicle treated BDL rats. I/R injury superimposed on these animals resulted in markedly elevated serum alanine transaminase (ALT), aspartate transaminase (AST), total bilirubin accompanied with increased neutrophil recruitment and lipid peroxidation. Preconditioning with CYA reduced the histological damage and serum liver injury markers. CYA also reduced neutrophil infiltration, proinflammatory cytokines such as TNF-? and IL-1ß expression of ?-smooth muscle actin and type 1 collagen resulting in reduced fibrosis. Furthermore CYA treated animals showed reduced cholangiocyte proliferation, and apoptosis. Hepatoprotection by CYA was conferred by reduced activation of protein kinase B (Akt) and extracellular signal regulated kinase (ERK). Endogenous Hh signaling in cholestasis exacerbates inflammatory injury during liver I/R. Blockade of Hh pathway represents a clinically relevant novel approach to limit I/R injury in cholestatic marginal liver.

Provided by American Chemical Society (news : web)