Availability and use of molecular hydrogen as an energy substrate for Helicobacter species

Molecular hydrogen is produced in the large intestine of animals due to the fermentation reactions of sugar catabolism. The gastric pathogen Helicobacter pylori and the liver pathogen Helicobacter hepaticus have the capacity to use molecular hydrogen as a respiratory substrate. The amount of the gas within tissues colonized by these pathogens is ample, and use of H2 significantly increases the stomach colonization ability of H. pylori.     

Flavonoid evolution: an enzymic approach

Flavonoid evolution in land plants is discussed from an enzymic point of view, based on the present day distribution of the major subgroups of flavonoids in bryophytes, lower and higher vascular plants. The importance of varied functions in the origin of pathways with a series of sequential steps leading to end-products is considered; it is argued that the initial function is that of an internal regulatory agent, rather than as a filter against ultraviolet irradiation. The basic synthases, hydroxylases, and reductases of flavonoid pathways are presumed to have evolved from enzymes of primary metabolism. A speculative scheme is presented of flavonoid evolution within a primitive group of algae derived from a Charophycean rather than a Chlorophycean line, as a land environment was invaded. Flavonoid evolution was preceded by that of the phenylpropanoid and malonyl-coenzyme A pathways, but evolved prior to the lignin pathway.     

The use of smoke acid as an alternative coagulating agent for natural rubber sheets' production

A comparative study of rubber sheets obtained using formic, acetic, and smoke acid as coagulants is shown for latex obtained from native Amazonian trees and also from commercial cultivated trees. The evaluation of both processes of coagulation was carried out by spectroscopic and physical-chemical analysis, showing no differences in the rubber sheets obtained. This new method of rubber sheet preparation was introduced into Amazonian rainforest rubber tapper communities, which are actually producing in large scale. The physical-mechanical properties were similar among a large sheets made by different rubber tapper communities using this new method.     

Hybrid benzothiazole analogs as antiurease agent: Synthesis and molecular docking studies

Benzothiazole analogs (1–20) have been synthesized, characterized by EI-MS and ¹H NMR, and evaluated for urease inhibition activity. All compounds showed excellent urease inhibitory potential varying from 1.4 ± 0.10 to 34.43 ± 2.10 μM when compared with standard thiourea (IC₅₀ 19.46 ± 1.20 μM). Among the series seventeen (17) analogs 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 16, 17, and 18 showed outstanding urease inhibitory potential. Analogs 15 and 19 also showed good urease inhibition activity. When we compare the activity of N-phenylthiourea 20 with all substituted phenyl derivatives (1–18) we found that compound 15 showed less activity than compound 20 having 3-methoxy substituent. The binding interactions of these active analogs were confirmed through molecular docking.     

The use of psyllium (isubgol) as an alternative gelling agent for microbial culture media

Psyllium (Isubgol), the mucilage husk of Plantago ovata, was successfully used as an alternative gelling agent (5% w/v as ground husk for pouring medium and 4% w/v as ground husk in combination with 0.5% w/v agar for slant) for microbial culture. Most of the undesirable features of psyllium-gelled media (slant as well as pouring) were removed by adding the u.v.-treated (20min) or oven-sterilized (120^°C for 1h) psyllium as ground husk to autoclaved medium at 50–60^°C under aseptic condition just before pouring.     

The use of DPPD (N,N'-diphenyl-P-phenylenediamine) as an anti-inflammatory agent

The anti-oxidant compound, DPPD, was found to be an effctive anti-inflammatory compound by inhibiting carrageenin rat paw edema, adjuvant athritis and serum sickness expression of vascular and renal injury. It is proposed these effects are due to the inhibition of prostaglandin synthesis or fatty acid peroxide formation.     

Thalidomide as an anti-cancer agent

Thalidomide is a glutamic acid derivative initially introduced as a sedative hypnotic nearly forty years ago. It was withdrawn following numerous reports linking it to a characteristic pattern of congenital abnormalities in babies born to mothers who used the drug for morning sickness. It has gradually been re-introduced into clinical practice over the past two decades, albeit under strict regulation, since it was found to be useful in the management of erythema nodosum leprosum and HIV wasting syndrome. Recognition of its anti-angiogenic effect led to its evaluation in the treatment of various malignancies, where angiogenesis has been shown to play an important role. Numerous clinical trials done over the past four years have confirmed the significant anti-myeloma activity of this drug. It has also shown promise in preliminary trials in the treatment of a variety of different malignant diseases. The mechanisms of its antineoplastic effects continue to be the focus of ongoing research. It has become clear that even though its anti angiogenic effects play a significant role in the anti-tumor activity, there are other properties of this drug which are responsible as well. It also possesses anti-TNF alpha activity, which has led to its evaluation in several inflammatory states. In this concise review, we briefly describe the historical background and pharmacological aspects of this drug. We have concisely reviewed the current knowledge regarding mechanisms of its anti-neoplastic activity and the results of various clinical trials in oncology.     

Reserpine as an uncoupling agent

1. Reserpine, like the uncoupling agent, 2,4-dinitrophenol prevents oxidative phosphorylation but stimulates the rate at which oxygen is reduced.

2. Both reserpine and 2,4-dinitrophenol fail to stimulate oxygen uptake by isolated mitochondria in the presence of arginine.

3. Both 2,4-dinitrophenol and reserpine induce proton permeability in the mitochondrial membrane so that H⁺ is absorbed from the suspending medium.

4. When the reaction system contains reserpine, accumulation of Ca²⁺ by mitochondria is inhibited.

5. Reserpine decreases both ADP:O and P:O ratios which strongly suggest that reserpine is an uncoupling agent.     

Purification, molecular and enzymic characterization of an acid RNase from the insect Ceratitis capitata

An acid ribonuclease has been purified from the insect Ceratitis capitata. The specific activity of the purified enzyme is 580 units/mg. This enzyme is a single polypeptide chain of about 35.5 kDa, containing only one disulfide bridge and no free -SH groups. The A0.1%1cm at 280 nm is 1.90. The hydrodynamic radius of the native enzyme is 2.5 nm. The secondary structure of this RNase is composed of 10% alpha-helix, 31% beta-structure and 59% aperiodic conformation with an average number of residues per helical segment of 10, based on circular dichroic measurements. Optimum parameters for the enzyme activity are pH 5.5, 0.15 M ionic strength and 40 degrees C. Divalent cations are not required for the enzymic catalysis. This enzyme has been characterized as cyclizing endoribonuclease.     

Encapsulated boron as an osteoinductive agent for bone scaffolds

The aim of this study was to develop boron (B)-releasing polymeric scaffold to promote regeneration of bone tissue. Boric acid-doped chitosan nanoparticles with a diameter of approx. 175 nm were produced by tripolyphosphate (TPP)-initiated ionic gelation process. The nanoparticles strongly attached via electrostatic interactions into chitosan scaffolds produced by freeze-drying with approx. 100 μm pore diameter. According to the ICP-OES results, following first 5 h initial burst release, fast release of B from scaffolds was observed for 24 h incubation period in conditioned medium. Then, slow release of B was performed over 120 h. The results of the cell culture studies proved that the encapsulated boron within the scaffolds can be used as an osteoinductive agent by showing its positive effects on the proliferation and differentiation of MC3T3-E1 preosteoblastic cells.     

Alginate as an antiglycating agent for human serum albumin

Hyperglycemia and the accumulation of advanced glycation endproducts (AGEs) in tissues and serum have important roles in diabetic complications. Therefore, the identification of anti-glycation compounds is attracting considerable interest. In this study, the interaction of human serum albumin (HSA) with fructose, in the absence and presence of alginate, was studied by circular dichroism, absorbance and fluorescence techniques. The characterization study of AGEs was performed using autofluorescence, fibrillar formation, the increase in absorbance and the quantification of free lysine side chains. The results indicate that alginate inhibits the fructation of HSA as observed by a reduction in the formation of fluorescent AGEs and fibrils. Furthermore, alginate reduces the amount of modified lysine side chains, signified by the lack of increase in absorbance, and increases the helicity of this protein.     

Curcumin as an anti-inflammatory agent: Implications to radiotherapy and chemotherapy

Cancer is the second cause of death worldwide. Chemotherapy and radiotherapy are the most common modalities for the treatment of cancer. Experimental studies have shown that inflammation plays a central role in tumor resistance and the incidence of several side effects following both chemotherapy and radiotherapy. Inflammation resulting from radiotherapy and chemotherapy is responsible for adverse events such as dermatitis, mucositis, pneumonitis, fibrosis, and bone marrow toxicity. Chronic inflammation may also lead to the development of second cancer during years after treatment. A number of anti-inflammatory drugs such as nonsteroidal anti-inflammatory agents have been proposed to alleviate chronic inflammatory reactions after radiotherapy or chemotherapy. Curcumin is a well-documented herbal anti-inflammatory agents. Studies have proposed that curcumin can help management of inflammation during and after radiotherapy and chemotherapy. Curcumin targets various inflammatory mediators such as cyclooxygenase-2, inducible nitric oxide synthase, and nuclear factor κB (NF-κB), thereby attenuating the release of proinflammatory and profibrotic cytokines, and suppressing chronic production of free radicals, which culminates in the amelioration of tissue toxicity. Through modulation of NF-κB and its downstream signaling cascade, curcumin can also reduce angiogenesis, tumor growth, and metastasis. Low toxicity of curcumin is linked to its cytoprotective effects in normal tissues. This protective action along with the capacity of this phytochemical to sensitize tumor cells to radiotherapy and chemotherapy makes it a potential candidate for use as an adjuvant in cancer therapy. There is also evidence from clinical trials suggesting the potential utility of curcumin for acute inflammatory reactions during radiotherapy such as dermatitis and mucositis.