Publications

Multiple drug-resistant bacterial strains are showing new different mechanisms to overcome the antimicrobial action, which reduces the efficacy of conventional antibiotics. Therefore, drug discovery research has focused on developing fast, effective, and safe alternatives to prevent this multi-resistance. Phlorotannins are a diverse class of polyphenols, secondary metabolites described in brown algae, that are mainly constituted of polymers of phloroglucinol and, depending on their linkage and structure, can be classified mainly as fucols, fucophlorethols, eckols, and phloroethols. These polyphenols have been described in both macro- and microalgae, suggesting that they can be recovered from a great variety of sources. Phlorotannins have been extensively described to possess several biological properties, foremost as antioxidant and antimicrobial compounds. Several in vitro reports have described that phlorotannins showed growth inhibition and bactericidal effects against Gram+ (e.g., Bacillus cereus, Streptococcus epidermidis, Staphylococcus aureus) and Gram− bacteria (e.g., Salmonella sp., Campylobacter jejuni, Pseudomonas aeruginosa), also including antibiotic-resistant strains such as MRSA. Although the mechanisms of action of this group of compounds has not been fully elucidated, tannins could interact with membrane proteins and key metabolic enzymes, impeding bacterial growth and resulting in membrane lysis. Moreover, different phlorotannins were able to inhibit bacterial biofilm formation, production of quorum-sensing molecules, and also viral replication (e.g., influenza). Few in vivo studies support their effectiveness as antibiotics, whereas clinical trials studying other properties consistently report high bioavailability and null toxicity of phlorotannins. Considering current evidence, phlorotannins could be considered as interesting candidates for antibiotic therapy clinical trials. The diversity of these natural compounds provides a promising gateway for researchers and the pharmaceutical industry to develop novel nontoxic, cost-effective, and highly efficient antibacterial formulations with a broad scope of applications.

Image relaying is presented as a technique for aligning beams onto mm-sized target of high power laser. On the basis of summarizing the preceeding work on the near-field image relaying of multiple spatial filters, the far-filed image relaying is suggested firstly. The near-field and far-field image relaying properties of multiple spatial filters in laser beams automatic alignment system are analyzed. A geometrical optics approach and an ABCD ray matrix theory are used throughout. The reasonable and optimum scheme for automatically aligning multi-pass beam paths is presented and demonstrated on the multi-pass amplifier system of the SG-III prototype.

Metabolic syndrome includes a cluster of risk factors for many pathological conditions, including hyperglycemia, abdominal obesity, hyperlipidemia, and hypertension. Adansonia digitata L. (also known as baobab) is used in traditional African Medicine and recent studies showed that it improves the metabolism of carbohydrates and lipids. The aim of this study is to investigate the mechanisms of action associated with the beneficial effects of extracts from the edible parts of baobab (fruit pulp, leaves, raw and toasted seeds), evaluating their inhibitory activity against: alpha-amylase, alpha-glucosidase, angiotensin-converting enzyme, 3-hydroxy-3-methyl-glutaryl-coenzyme A reductase, and pancreatic lipase. Baobab fruit pulp and leaf extracts resulted to be the most active ones and were then tested on the differentiation process of SW-872 human liposarcoma cells to mature adipocytes. The addition of these latter extracts did not affect triglyceride accumulation, indicating a neutral impact on this parameter. The findings here reported help to explain the growing amount of evidence on the biological properties of baobab and provide suggestions about their use in food and nutraceutical fields.

The synergic effect of ultraviolet (UV) and ultrasound (US) radiation when used in combination has been exploited for efficient generation of Hg vapour in atomic absorption spectrometry. For this purpose, a batch reactor is designed and coupled to an atomic absorption spectrometer arranged with a quartz cell in the optical path. UV irradiation achieved a fast reduction of ionic Hg to elemental Hg in the presence of formic acid used as a precursor of reducing species, whereas high intensity ultrasound irradiation allowed a fast mass transfer from the liquid sample to the gas phase of the reactor. UV reduction times of 10 s and 30 s were needed for Hg(II) and CH3Hg+, respectively. A 5 s ultrasound irradiation time was enough to yield an atomic absorption signal integrable within 20 s. Formic acid was useful not only to assist the photoreduction but also to solubilize the biological tissues. The method was applied to the determination of total Hg in four certified reference materials corresponding to marine biological tissues following fast ultrasound-assisted solubilization with formic acid. LODs of Hg in the biological tissues ranged from 0.025 to 0.06 μg g−1. Within-batch precision was around 4%, whilst between-batch precision was in the range 6–11%.

Abstract Tropane alkaloids (TA) including hyoscyamine, anisodamine, scopolamine and anisodine, are used medicinally as anticholinergic agents with increasing market demand, so it is very important to improve TA production by metabolic engineering strategy. Here, we report the simultaneous introduction of genes encoding the branch-controlling enzyme tropinone reductase I (TRI, EU424321) and the downstream rate-limiting enzyme hyoscyamine-6β-hydroxylase (H6H, EF187826) involved in TA biosynthesis into Anisodus acutangulus hairy roots by Agrobacterium-mediated gene transfer technology. Transgenic hairy root lines expressing both TRI and H6H (TH lines) produced significantly higher (P < 0.05) levels of TA compared with the control and single gene transformed lines (T or H lines). The best double gene transformed line (TH53) produced 4.293 mg g−1 TA, which was about 4.49-fold higher than that of the control lines (0.96 mg g−1). As far as it is known, this is the first report on simultaneous introduction of TRI and H6H genes into TA-producing plant by biotechnological approaches. Besides, the content of anisodine was also greatly improved in A. acutangulus by over-expression of AaTRI and AaH6H genes. The average content of anisodine in TH lines was 0.984 mg g−1 dw, about 18.57-fold of BC lines (0.053 mg g−1 dw). This is the first time that this phenomenon has been found in TA-producing plants.

Figure representing the number of transcripts obtained after the assembly of increasing number of mapped reads. (XLSX 743 kb)