Cytotoxicity and Inhibition of Lymphocyte Proliferation of Fasciculatin,a Linear Furanosesterterpene Isolated from Ircinia variabilis Collected from the Atlantic Coast of Morocco

Fasciculatin, a furanosesterterpene isolated from the marine sponge Ircinia variabilis from the Atlantic Coast of Morocco, has been evaluated for its influence on a mitogen-induced proliferation of human lymphocytes and growth of human tumor cell lines.     

Anti-Osteoclastogenic and Antibacterial Effects of Chlorinated Polyketides from the Beibu Gulf Coral-Derived Fungus Aspergillus unguis GXIMD 02505

One new depsidone derivative, aspergillusidone H (3), along with seven known biosynthetically related chlorinated polyketides, were obtained from the Beibu Gulf coral-derived fungus Aspergillus unguis GXIMD 02505. Their structures were determined by comprehensive physicochemical and spectroscopic data interpretation. Notably, the X-ray crystal structure of 2 and the previously unknown absolute configuration of 8, assigned by ECD calculations, are described here for the first time. Compounds 1–5, 7 and 8 exhibited inhibition of lipopolysaccharide (LPS)-induced NF-κB in RAW 264.7 macrophages at 20 μM. In addition, the two potent inhibitors (2 and 7) dose-dependently suppressed RANKL-induced osteoclast differentiation without any evidence of cytotoxicity in bone marrow macrophages cells (BMMs). This is the first report of osteoclastogenesis inhibitory activity for the metabolites of these kinds. Besides, compounds 1, 2, 4, and 6–8 showed inhibitory activity against marine biofilm-forming bacteria, methicillin-resistant Staphylococcus aureus, Microbulbifer variabilis, Marinobacterium jannaschii, and Vibrio pelagius, with their MIC values ranging from 2 to 64 μg/mL. These findings provide a basis for further development of chlorinated polyketides as potential inhibitors of osteoclast differentiation and/or for use as anti-fouling agents.     

Sensitivity of Neurospora crassa to a Marine-Derived Aspergillus tubingensis Anhydride Exhibiting Antifungal Activity That Is Mediated by the MAS1 Protein

The fungus Aspergillus tubingensis (strain OY907) was isolated from the Mediterranean marine sponge Ircinia variabilis. Extracellular extracts produced by this strain were found to inhibit the growth of several fungi. Among the secreted extract components, a novel anhydride metabolite, tubingenoic anhydride A (1) as well as the known 2-carboxymethyl-3-hexylmaleic acid anhydride, asperic acid, and campyrone A and C were purified and their structure elucidated. Compound 1 and 2-carboxymethyl-3-hexylmaleic acid anhydride inhibited Neurospora crassa growth (MIC = 330 and 207 μM, respectively) and affected hyphal morphology. We produced a N. crassa mutant exhibiting tolerance to 1 and found that a yet-uncharacterized gene, designated mas-1, whose product is a cytosolic protein, confers sensitivity to this compound. The ∆mas-1 strain showed increased tolerance to sublethal concentrations of the chitin synthase inhibitor polyoxin D, when compared to the wild type. In addition, the expression of chitin synthase genes was highly elevated in the ∆mas-1 strain, suggesting the gene product is involved in cell wall biosynthesis and the novel anhydride interferes with its function.     

Palyosulfonoceramides A and B: Unique Sulfonylated Ceramides from the Brazilian Zoanthids Palythoa caribaeorum and Protopalyhtoa variabilis

The zoanthids Palythoa caribaeorum and Protopalythoa variabilis are among the most abundant marine species along the Brazilian coast. We now report the isolation and structure elucidation of two unprecedented sulfonylated ceramides, palyosulfonoceramide A (1) and palyosulfonoceramide B (2) from specimens collected off Brazil’s northeastern coast. The structures of 1 and 2 were established using a combination of NMR analyses, including: evaluation of ¹H, ¹³C, ¹H–¹H COSY, ¹H–¹³C HSQC, ¹H–¹³C HMBC, and ¹H–¹⁵N HMBC NMR spectra, high-resolution mass spectrometry and chemical degradation. In addition, we also isolated the corresponding known ceramides, N-((2S,3R,4E,8E)-1,3-dihydroxyoctadeca-4,8-dien-2-yl)-hexadecanamide (3) and N-((2S,3R,4E)-1,3-dihydroxyoctadeca-4-en-2-yl)-hexadecanamide (4), which provided further support for the assignments of 1 and 2.     

Sublethal effect of avermectin and acetamiprid on the mortality of different life stages of Brontispa longissima (Gestro) (Coleoptera: Hispidae) and its larvae parasitoid Asecodes hispinarum Bouček (Hymenoptera: Eulophidae)

The beneficial parasitoid Asecodes hispinarum Bouček plays an important role in integrated pest management (IPM) of the coconut leaf beetle, Brontispa longissima (Gestro), in China. A. hispinarum females parasitize 3rd to 4th instars B. longissima larvae. Hatched parasitoid larvae develop within the host, and parasitoid adults emerge through holes that they chew through the cuticle of the host. Although chemicals serve as the main short term control agents, the compatibility of biological and chemical control has never been investigated for this system. This study examined the responses of immature and adult B. longissima and its larval parasitoid A. hispinarum to avermectin and acetamiprid. Avermectin caused complete mortality of 2nd to 4th instar larvae, and of adults of B. longissima at 10, 15 and 2 d after treatment, respectively. However, 26.7% of the 2nd instar larvae, 55.3% of the 4th instar larvae, and 74%, of adult B. longissima were still alive 40 d after acetamiprid application. Following avermectin exposure, 17.5%, 9.2% and 23% of mummified B. longissima larvae contained viable adult parasitoids for the parasitoid egg, larva and pupa treatments, respectively, and the numbers of dead parasitoids per mummy were 3.3, 7.2 and 13.3 for the egg, larva and adult treatments, respectively. However, for acetamiprid treatment, 70–75.9% of mummified B. longissima larvae contained viable adult parasitoids in all three stage treatments, and the number of dead parasitoids per mummy was 2.8, 2 and 3.4 in egg, larva and adult treatments, respectively. This study showed that a sublethal dose of avermectin is more toxic than acetamiprid to B. longissima and A. hispinarum. Therefore, direct contact of the parasitoid with avermectin should be avoided when this insecticide is used to control B. longissima.     

Pyrethroid synergism by esterase inhibition in Spodoptera littoralis (Boisduval) larvae

The susceptibility of cotton leafworm, Spodoptera littoralis (Boisduval) larvae to poisoning by trans-permethrin and cis-cypermethrin was increased when these pyrethroids were applied topically after the larvae had ingested profenofos, monocrotophos or azinphos-methyl for 24 h. An ingested dose of 4 nmol profenofos per larva gave a synergism factor of about threefold for both trans-permethrin and cis-cypermethrin. These pyrethroids were not synergized by oxidase inhibitors such as piperonyl butoxide, SV-1 and MPP ingested at 80 nmol/larva. Esterase preparations of larval gut hydrolysed trans-permethrin two to three times more rapidly than cis-permethrin, deltamethrin, trans- or cis-cypermethrin. Integument esterase(s) are less active but show a similar preference for trans-permethrin. The gut esterase(s) hydrolysing trans-permethrin are more sensitive in vitro and in vivo to inhibition by profenofos than by azinphos-methyl or monocrotophos. The susceptibility of S. littoralis larvae to pyrethroids appears to be limited by pyrethroid esterases in the gut. Organophosphorous compounds inhibiting these detoxifying enzymes serve as synergists.     

Postegression Feeding Enhances Growth,Survival, and Nutrient Acquisition in the Endoparasitoid Toxoneuron nigriceps (Hymenoptera: Braconidae)

Toxoneuron nigriceps Viereck (Hymenoptera: Braconidae), a koinobiont endoparasitoid of the tobacco budworm, Heliothis virescens F. (Lepidoptera: Noctuidae), derives nutrition from the host hemolymph during the internal portion of its larval development but feeds destructively on host tissues externally after egression. To investigate the importance of this tissue-feeding phase, and to evaluate the behaviors associated with postegression feeding, T. nigriceps larvae were subjected to one of four treatments: 1) allowed to carry out normal tissue feeding, 2) deprived of tissue feeding, 3) presented with tissues scraped away from the host remains, and 4) fed tissues scraped from an unparasitized H. virescens larva. Additionally, total carbohydrates, lipids, and proteins were quantified from pre and posttissue feeding T. nigriceps larvae to examine the effect of postegression feeding on parasitoid nutritional physiology. Parasitoids that received no tissues after egression, or that received tissue from an unparasitized H. virescens larva, had significantly smaller body masses at all stages than those allowed to feed naturally or fed tissues scraped from a parasitized host. Parasitoids that underwent normal host feeding after egression also reached larger masses then those fed scraped host tissue. Parasitoids that received no tissue after egression survived to adulthood significantly less often than those that were presented with any H. virescens tissue. This suggests that postegression tissue feeding is a vital developmental step for T. nigriceps, and that T. nigriceps will not only feed when normal postegression behavior is disrupted, but will also feed on unparasitized tissue. The quantification of macronutrients in the tissues of pre and posttissue feeding T. nigriceps larvae showed significantly elevated proportions of proteins, lipids, and carbohydrates in the tissues of larvae that had completed feeding, with the greatest difference being in total lipids.     

Influence of Dietary Lipids and Environmental Salinity on the n-3 Long-Chain Polyunsaturated Fatty Acids Biosynthesis Capacity of the Marine Teleost Solea senegalensis

Fish vary in their ability to biosynthesise long-chain polyunsaturated fatty acids (LC-PUFA) depending upon the complement and function of key enzymes commonly known as fatty acyl desaturases and elongases. It has been reported in Solea senegalensis the existence of a Δ4 desaturase, enabling the biosynthesis of docosahexaenoic acid (DHA) from eicosapentaenoic acid (EPA), which can be modulated by the diet. The present study aims to evaluate the combined effects of the partial replacement of fish oil (FO) with vegetable oils and reduced environmental salinity in the fatty acid composition of relevant body compartments (muscle, hepatocytes and enterocytes), the enzymatic activity over α-linolenic acid (ALA) to form n-3 LC-PUFA through the incubation of isolated hepatocytes and enterocytes with [1-¹⁴C] 18:3 n-3, and the regulation of the S. senegalensis fads2 and elovl5 in the liver and intestine. The presence of radiolabelled products, including 18:4n-3, 20:4n-3 and EPA, provided compelling evidence that a complete pathway enabling the biosynthesis of EPA from ALA, establishing S. senegalensis, has at least one Fads2 with ∆6 activity. Dietary composition prevailed over salinity in regulating the expression of fads2, while salinity did so over dietary composition for elovl5. FO replacement enhanced the proportion of DHA in S. senegalensis muscle and the combination with 20 ppt salinity increased the amount of n-3 LC-PUFA in hepatocytes.     

A New Dibenz[b,e]oxepine Derivative, 1-Hydroxy-10-methoxy-dibenz[b,e]oxepin-6,11-dione,from a Marine-Derived Fungus,Beauveria bassiana TPU942

1-Hydroxy-10-methoxy-dibenz[b, e]oxepin-6,11-dione (1) was obtained from the culture broth of a marine-derived fungus, Beauveria bassiana TPU942, isolated from a marine sponge collected at Iriomote Island in Okinawa, together with two known compounds, chrysazin (2) and globosuxanthone A (3). The structure of 1 was elucidated on the basis of its spectroscopic data (HREIMS, 1D and 2D NMR experiments including ¹H–¹H COSY, HMQC and HMBC spectra). Dibenz[b, e]oxepines are rare in nature, and only six natural products have been reported. Therefore, compound 1 is the seventh natural product in this class. Compounds 2 and 3 showed an antifungal activity against Candida albicans, and 3 inhibited the cell growth against two human cancer cell lines, HCT-15 (colon) and Jurkat (T-cell lymphoma). Compound 1 did not show an apparent activity in the same bioassays.     

Tetrodotoxin concentrations in Pleurobranchaea maculata: temporal, spatial and individual variability from New Zealand populations

Tetrodotoxin (TTX) is a potent neurotoxin that has been identified in a range of phylogenetically unrelated marine and terrestrial organisms. Tetrodotoxin was recently detected in New Zealand in Pleurobranchaea maculata (the grey side-gilled sea slug). From June 2010 to June 2011 wild specimens were collected from 10 locations around New Zealand. At one site (Narrow Neck Beach, Auckland) up to 10 individuals were collected monthly for 6 months. Attempts were also made to rear P. maculata in captivity. Tetrodotoxin was detected in samples from eight of the ten sites. The highest average (368.7 mg kg⁻¹) and maximum (1414.0 mg kg⁻¹) concentrations were measured in samples from Illiomama Rock (Auckland). Of the toxic populations tested there was significant variability in TTX concentrations among individuals, with the highest difference (62 fold) measured at Illiomama Rock. Tetrodotoxin concentrations in samples from Narrow Neck Beach varied temporally, ranging from an average of 184 mg kg⁻¹ in June 2010 to 17.5 mg kg⁻¹ by December 2010. There was no correlation between TTX levels and mass. The highest levels correspond with the egg laying season (June–August) and this, in concert with the detection of high levels of TTX in eggs and early larval stages, suggests that TTX may have a defensive function in P. maculata. Only one larva was successfully reared to full maturation and no TTX was detected.     

First Total Syntheses and Antimicrobial Evaluation of Penicimonoterpene,a Marine-Derived Monoterpenoid,and Its Various Derivatives

The first total synthesis of marine-derived penicimonoterpene (±)-1 has been achieved in four steps from 6-methylhept-5-en-2-one using a Reformatsky reaction as the key step to construct the basic carbon skeleton. A total of 24 new derivatives of 1 have also been designed and synthesized. Their structures were characterized by analysis of their ¹H NMR, ¹³C NMR and HRESIMS data. Some of them showed significant antibacterial activity against Aeromonas hydrophila, Escherichia coli, Micrococcus luteus, Staphylococcus aureus, Vibrio anguillarum, V. harveyi and/or V. parahaemolyticus, and some showed activity against plant-pathogenic fungi (Alternaria brassicae, Colletotrichum gloeosporioides and/or Fusarium graminearum). Some of the derivatives exhibited antimicrobial MIC values ranging from 0.25 to 4 μg/mL, which were stronger than those of the positive control. Notably, Compounds 3b and 10 showed extremely high selectively against plant-pathogenic fungus F. graminearum (MIC 0.25 μg/mL) and pathogenic bacteria E. coli (MIC 1 μg/mL), implying their potential as antimicrobial agents. SAR analysis of 1 and its derivatives indicated that modification of the carbon-carbon double bond at C-6/7, of groups on the allylic methylene unit and of the carbonyl group at C-1, effectively enhanced the antimicrobial activity.     

Effects of Ethanol Extracts from Grateloupia elliptica,a Red Seaweed,and Its Chlorophyll Derivative on 3T3-L1 Adipocytes: Suppression of Lipid Accumulation through Downregulation of Adipogenic Protein Expression

Grateloupia elliptica (G. elliptica) is a red seaweed with antioxidant, antidiabetic, anticancer, anti-inflammatory, and anticoagulant activities. However, the anti-obesity activity of G. elliptica has not been fully investigated. Therefore, the effect of G. elliptica ethanol extract on the suppression of intracellular lipid accumulation in 3T3-L1 cells by Oil Red O staining (ORO) was evaluated. Among the eight red seaweeds tested, G. elliptica 60% ethanol extract (GEE) exhibited the highest inhibition of lipid accumulation. GEE was the only extract to successfully suppress lipid accumulation among ethanol extracts from eight red seaweeds. In this study, we successfully isolated chlorophyll derivative (CD) from the ethyl acetate fraction (EA) of GEE by high-performance liquid chromatography and evaluated their inhibitory effect on intracellular lipid accumulation in 3T3-L1 adipocytes. CD significantly suppressed intracellular lipid accumulation. In addition, CD suppressed adipogenic protein expression such as sterol regulatory element-binding protein-1 (SREBP-1), peroxisome proliferator-activated receptor-γ (PPAR-γ), CCAAT/enhancer-binding protein-α (C/EBP-α), and fatty acid binding protein 4 (FABP4). Taken together, our results indicate that CD from GEE inhibits lipid accumulation by suppressing adipogenesis via the downregulation of adipogenic protein expressions in the differentiated adipocytes. Therefore, chlorophyll from G. elliptica has a beneficial effect on lipid metabolism and it could be utilized as a potential therapeutic agent for preventing obesity.     

Determination of (1→3),(1→4)-β-D-Glucanase Activity by a Calcofluor-Flow Injection Analysis Method

A new methodology for the determination of (1→3),(1→4)-β-d-glucanase activity has been developed. The concentration decay curves corresponding to the depolymerisation of high molecular weight barley (1→3),(1→4)-β-d-glucan by pure (1→3),(1→4)-β-d-glucanase (E.C. 3.2.1.73) fromBacillus subtilisand by crude (1→3),(1→4)-β-d-glucanase from different malts were monitored by the Calcofluor-FIA method. In all cases, the high molecular weight (17Instituto de Agroquı́mica y Tecnologı́a de Alimentos (CSIC)rarr;3),(1→4)-β-d-glucan decay curves fitted very well to an empirical formula describing the change in substrate concentration with time. The curves possess an inflexion point at which the depolymerisation rate of the substrate reaches a maximum. This maximum depolymerisation rate correlates with the initial concentrations of enzyme and substrate,E_oandS_o, and the enzyme kinetic constantsV_mandK_mthrough a hyperbola similar to that of Michaelis-Menten. TheK_mdetermined forB. subtilisβ-glucanase was rather low, about 0·99 g β-glucan/l, when compared with those corresponding to (1→3),(1→4)-β-d-glucanase from different malts, which were, in turn, practically identical at about 2·92 g β-glucan/l. Experiments with barley (1→3),(1→4)-β-d-glucans of different high initial molecular weights showed that initial molecular weight had no influence on the kinetics. Thus, this new methodology permits the determination of (1→3),(1→4)-β-d-glucanase activity in a direct way, i.e. the amount of (1→3),(1→4)-β-d-glucan degraded per amount of enzyme (or malt) per unit of time. Moreover, since it is insensitive to the initial molecular weight of the substrate, it seems to be well-suited for inter-laboratory comparisons of (1→3),(1→4)-β-d-glucanase activities.     

Red Algae (Rhodophyta) from the Coast of Madagascar: Preliminary Bioactivity Studies and Isolation of Natural Products

Several species of red algae (Rhodophyta) from the coastal regions of Madagascar have been investigated for their natural products. The most abundant compound was cholesterol (5) in combination with a series of oxidized congeners. The brominated indoles 1–3 along with the sesquiterpene debilone (4) have been isolated from Laurencia complanata. For the first time, debilone (4) has been obtained from a marine plant. From the methanol extract of Calloseris sp., we have achieved the second isolation of the unusual A-ring contracted steroids (−)-2-ethoxycarbonyl-2β-hydroxy-A-nor-cholest-5-en-4-one (9) and phorbasterone B (10). The crude extracts of Laurencia complanata exhibited antimicrobial activity against Bacillus cereus, Staphylococcus aureus, Streptococcus pneumoniae, and Candida albicans.     

Study of the Structure–Activity Relationship of an Anti-Dormant Mycobacterial Substance 3-(Phenethylamino)Demethyl(oxy)aaptamine to Create a Probe Molecule for Detecting Its Target Protein

The current tuberculosis treatment regimen is long and complex, and its failure leads to relapse and emergence of drug resistance. One of the major reasons underlying the extended chemotherapeutic regimen is the ability of Mycobacterium tuberculosis to attain a dormant state. Therefore, the identification of new lead compounds with chemical structures different from those of conventional anti-tuberculosis drugs is essential. The compound 3-(phenethylamino)demethyl(oxy)aaptamine (PDOA, 1), isolated from marine sponge of Aaptos sp., is known as an anti-dormant mycobacterial substance, and has been reported to be effective against the drug resistant strains of M. tuberculosis. However, its target protein still remains unclear. This study aims to clarify the structure–activity relationship of 1 using 15 synthetic analogues, in order to prepare a probe molecule for detecting the target protein of 1. We succeeded in creating the compound 15 with a photoaffinity group that retained antimicrobial activity, which proved to be a suitable probe molecule for identifying the target protein of 1.     

Effect of Salicornia herbacea on Osteoblastogenesis and Adipogenesis in Vitro

Bone-related complications are among the highest concerning metabolic diseases in the modern world. Bone fragility and susceptibility to fracture increase with age and diseases like osteoporosis. Elevated adipogenesis in bone results in osteoporosis and loss of bone mass when coupled with lack of osteoblastogenesis. In this study the potential effect of Salicornia herbacea extract against osteoporotic conditions was evaluated. Adipogenesis inhibitory effect of S. herbacea has been evidenced by decreased lipid accumulation of differentiating cells and expression levels of crucial adipogenesis markers in 3T3-L1 pre-adipocytes. S. herbacea treatment reduced the lipid accumulation by 25% of the control. In addition, mRNA expression of peroxisome proliferator-activated receptor (PPAR)γ, CCAAT/enhancer-binding protein (C/EBP)α and sterol regulatory element binding protein (SREBP)1c were inhibited by the presence of S. herbacea. Bone formation enhancement effect of S. herbacea was also confirmed in MC3T3-E1 pre-osteoblasts. The presence of S. herbacea significantly elevated the alkaline phosphatase (ALP) activity by 120% at a concentration of 100 μg/mL in differentiating osteoblasts. S. herbacea also significantly increased the expression of osteoblastogenesis indicators, ALP, bone morphogenetic protein (BMP)-2, osteocalcin and collagen type I (collagen-I). In conclusion, S. herbacea possess potential to be utilized as a source of anti-osteoporotic agent that can inhibit adipogenesis while promoting osteoblastogenesis.     

Antimicrobial Diterpene Alkaloids from an Agelas citrina Sponge Collected in the Yucatán Peninsula

Three new diterpene alkaloids, (+)-8-epiagelasine T (1), (+)-10-epiagelasine B (2), and (+)-12-hydroxyagelasidine C (3), along with three known compounds, (+)-ent-agelasine F (4), (+)-agelasine B (5), and (+)-agelasidine C (6), were isolated from the sponge Agelas citrina, collected on the coasts of the Yucatán Peninsula (Mexico). Their chemical structures were elucidated by 1D and 2D NMR spectroscopy, HRESIMS techniques, and a comparison with literature data. Although the synthesis of (+)-ent-agelasine F (4) has been previously reported, this is the first time that it was isolated as a natural product. The evaluation of the antimicrobial activity against the Gram-positive pathogens Staphylococcus aureus, Streptococcus pneumoniae, Enterococcus faecalis showed that all of them were active, with (+)-10-epiagelasine B (2) being the most active compound with an MIC in the range of 1–8 µg/mL. On the other hand, the Gram-negative pathogenes Acinetobacter baumannii, Pseudomonas aeruginosa, and Klebsiella pneumoniae were also evaluated, and only (+)-agelasine B (5) showed a moderate antibacterial activity with a MIC value of 16 μg/mL.     

Use of essential oil of Laurus nobilis obtained by means of a supercritical carbon dioxide technique against post harvest spoilage fungi

The aspects of the antifungal activity of essential oil of laurel (Laurus nobilis) obtained by means of a supercritical carbon dioxide (SFE-CO₂) technique against post harvest spoilage fungi, have been studied in this research work by tests performed under in vitro and in vivo conditions. The measurement of antifungal activity of the oil, for its potential application as botanical fungicide, is very useful to find alternatives to synthetic fungicides. The present paper reports, for the first time, the results about the antifungal activity of laurel oil, obtained by a semi-industrial process that utilize a SFE-CO₂ technique, against three plant pathogenic fungi. The determination of the main active substances was carried out by gas chromatography analysis: laurel oil was characterized by high content (≥10%) of 1.8-cineole, linalool, terpineol acetate, methyl eugenol and a low content (<10%) of linalyl acetate, eugenol, sabinene, β-pinene, α-terpineol. The inhibition of the mycelial growth of Botrytis cinerea, Monilinia laxa and Penicillium digitatum was evaluated in vitro at the concentration range of 200, 400, 600, 800 and 1000 μg/mL. M. laxa was totally inhibited by application of the oil at the lowest concentration, B. cinerea was completely inhibited at the highest concentration, and a fungistatic action was observed in both cases. P. digitatum was only partially inhibited at all the concentration ranges. The activity of the oil, placed in the form of spray on the fruit skin at the concentration range of 1, 2 and 3 mg/mL, was studied by biological tests. Both curative and protective activities of the oil have been evaluated on peaches, kiwifruits, oranges and lemons artificially inoculated with M. laxa, B. cinerea and P. digitatum, respectively. A very good antifungal activity has been found on kiwifruits and peaches when the oil was placed before the inoculation at a concentration of 3 mg/mL (68 and 91% of decay inhibition respectively). The same activity has been found on peaches when the oil was placed after the infection (76% of decay inhibition). The application of the oil did not caused any phytotoxic effect and kept any fruit flavour, fragrance or taste. This study has demonstrated that the essential oil of L. nobilis extracted by a SFE-CO₂ technique, is one potential and promising antifungal agent which could be used as botanical fungicide in the postharvest protection of peaches and kiwifruits against M. laxa and B. cinerea.     

Characterization of Neoagarooligosaccharide Hydrolase BpGH117 from a Human Gut Bacterium Bacteroides plebeius

α-Neoagarobiose (NAB)/neoagarooligosaccharide (NAO) hydrolase plays an important role as an exo-acting 3,6-anhydro-α-(1,3)-L-galactosidase in agarose utilization. Agarose is an abundant polysaccharide found in red seaweeds, comprising 3,6-anhydro-L-galactose (AHG) and D-galactose residues. Unlike agarose degradation, which has been reported in marine microbes, recent metagenomic analysis of Bacteroides plebeius, a human gut bacterium, revealed the presence of genes encoding enzymes involved in agarose degradation, including α-NAB/NAO hydrolase. Among the agarolytic enzymes, BpGH117 has been partially characterized. Here, we characterized the exo-acting α-NAB/NAO hydrolase BpGH117, originating from B. plebeius. The optimal temperature and pH for His-tagged BpGH117 activity were 35 °C and 9.0, respectively, indicative of its unique origin. His-tagged BpGH117 was thermostable up to 35 °C, and the enzyme activity was maintained at 80% of the initial activity at a pre-incubation temperature of 40 °C for 120 min. K_m and V_max values for NAB were 30.22 mM and 54.84 U/mg, respectively, and k_cat/K_m was 2.65 s⁻¹ mM⁻¹. These results suggest that His-tagged BpGH117 can be used for producing bioactive products such as AHG and agarotriose from agarose efficiently.