Chemical composition and antibacterial activities of seven Eucalyptus species essential oils leaves

Background

In this paper, we have studied the essential oils chemical composition of the leaves of seven Eucalyptus species developed in Tunisia. Eucalyptus leaves were picked from trees growing in different arboretums in Tunisia. Choucha and Mrifeg arboretums located in Sedjnene, region of Bizerte (Choucha: E. maideni, E. astrengens et E. cinerea; Mrifeg : E. leucoxylon), Korbous arboretums located in the region of Nabeul, North East Tunisia with sub-humid bioclimate, (E. lehmani), Souiniet-Ain Drahem arboretum located in region of Jendouba (E. sideroxylon, E. bicostata). Essential oils were individually tested against a large panel of microorganisms including Staphylococcus aureus (ATCC 6539), Escherichia coli (ATCC 25922), Enterococcus faecalis (ATCC29212), Listeria ivanovii (RBL 30), Bacillus cereus (ATCC11778).

Results

The yield of essential oils ranged from 1.2% to 3% (w/w) for the different Eucalyptus species. All essential oils contain α-pinene, 1,8-cineol and pinocarveol-trans for all Eucalyptus species studied. The 1,8-cineol was the major compound in all species (49.07 to 83.59%). Diameter of inhibition zone of essential oils of Eucalyptus species varied from 10 to 29 mm. The largest zone of inhibition was obtained for Bacillus cereus (E. astrengens) and the lowest for Staphylococcus aureus (E. cinerea). The essential oils from E. maideni, E. astrengens, E. cinerea (arboretum of Bizerte), E. bicostata (arboretum of Aindraham) showed the highest antibacterial activity against Listeria ivanovii and Bacillus cereus.

Conclusion

The major constituents of Eucalyptus leaves essential oils are 1,8-cineol (49.07 to 83.59%) and α-pinene (1.27 to 26.35%). The essential oils from E. maideni, E. astrengens, E. cinerea, E. bicostata showed the highest antibacterial activity against Listeria ivanovii and Bacillus cereus, they may have potential applications in food and pharmaceutical products.     

Potential Zoonotic Trematodes Recovered in Stray Cats from Kuwait Municipality,Kuwait

Stray cats are a common feature roaming the streets and alleys of Kuwait; they could be a source of parasites, including trematodes, that affect humans. A survey was conducted to identify feline trematodes and throw the light on their public health significance in Kuwait. Out of 240 stray cats trapped from different localities of Kuwait from June 2011 to May 2012, 59 (24.6%) were found to be infected with 14 species of trematodes. The most common were trematodes of the genus Heterophyes, particularly H. heterophyes and H. dispar that were found in respectively 15.8% and 10.8% of the cats examined. Other trematodes recorded, with lower prevalences, were Heterophyes nocens (2.9%), Haplorchis taichui (3.8%), Stictodora sawakinensis (2.1%), Stellantchasmus falcatus (1.6%), Echinochasmus japonicus (1.6%), and Mesostephanus dottrensi (1.3%). Centrocestus cuspidatus, Galactosomum fregatae, Ascocotyle sp., Mesostephanus appendiculatus, Haplorchis yokogawai, and Pygidiopsis genata showed the lowest prevalence (0.4%) and intensity. The majority of the trematodes are recorded for the first time in Kuwait and even in the Gulf region. The study reveals that stray cats are good indicators of fish-borne trematodes in the environment. As all trematodes recovered are zoonotic, their significance to public health should be considred.     

Reproductive biology of the Suez Canal spider crab Schizophrys aspera (H. Milne Edwards, 1834: Crustacea: Brachyura: Majidae)

A reproductive biology study of the spider crab Schizophrys aspera (H. Milne Edwards, 1834) was conducted in the Suez Canal from July 2012 to June 2013. The annual sex ratio (Male:Female) of S. aspera was female biased with values of 1:1.25. Out of the four ovarian development stages of this crab, two stages were observed in the Suez Canal throughout the whole year. The ovigerous crab’s carapace width varied from 28 to 52 mm. This crab species can spawn during most of the year in the canal water, with a peak during late spring and early winter. The fecundity of ovigerous females ranged between 2349 and 13600 eggs with a mean of 5494 ± 1486 eggs. Female crabs that reached sexual maturity exhibited a minimum carapace width varying between 22 and 46 mm, and fifty percentage of all ovigerous females showed a carapace width of 36 mm.     

Morphological and molecular information of a new species of Geleia (Ciliophora, Karyorelictea), with redescriptions of two Kentrophoros species from China

The morphology and infraciliature of three karyorelictean ciliates, Geleia sinica spec. nov. and two poorly known Kentrophoros species, K. flavus and K. gracilis, isolated from the intertidal zone of a beach at Qingdao, China, were investigated. Geleia sinica spec. nov. is distinguished from its congeners by the following combination of characters: body medium-sized and slender-cylindrical; with a conspicuous prebuccal fossa; 28–34 somatic kineties; about 40 short adoral polykineties; intrabuccal kinety composed of 25–34 dikinetids; paroral kineties composed of closely spaced dikinetids. The comparison with similar congeners clearly supports the validity of this new species based on morphological and small subunit (SSU) rRNA gene sequence data. In light of these new data the “well-known” morphotype, Geleia simplex (Fauré-Fremiet, 1951), is redefined. Two Kentrophoros species are redescribed and improved diagnoses are supplied. Kentrophoros flavus Raikov and Kovaleva, 1968 is mainly characterized by having about 33 macronuclei and 12 micronuclei forming a row that extends along the cell meridian, and 12–19 ciliary rows on the right side of the cell. Kentrophoros gracilis Raikov, 1963 is characterized by having about 14 macronuclei, 13 micronuclei and 10–13 kineties on the right side of the cell.     

Strategies for bacterial expression of protein-peptide complexes: application to solubilization of papillomavirus E6

E6 is a small oncoprotein involved in tumorigenesis induced by papillomaviruses (PVs). E6 often recognizes its cellular targets by binding to short motifs presenting the consensus LXXLL. E6 proteins have long resisted structural analysis. We found that bovine papillomavirus type 1 (BPV1) E6 binds the N-terminal LXXLL motif of the cellular protein paxillin with significantly higher affinity as compared to other E6/peptide interactions. Although recombinant BPV1 E6 was poorly soluble in the free state, provision of the paxillin LXXLL peptide during BPV1 E6 biosynthesis greatly enhanced the protein's solubility. Expression of BPV1 E6/LXXLL peptide complexes was carried out in bacteria in the form of triple fusion constructs comprising, from N- to C-terminus, the soluble carrier protein maltose binding protein (MBP), the LXXLL motif and the E6 protein. A TEV protease cleavage site was placed either between MBP and LXXLL motif or between LXXLL motif and E6. These constructs allowed us to produce highly concentrated samples of BPV1 E6, either covalently fused to the C-terminus of the LXXLL motif (intra-molecular complex) or non-covalently bound to it (inter-molecular complex). Heteronuclear NMR measurements were performed and showed that the E6 protein was folded with similar conformations in both covalent and non-covalent complexes. These data open the way to novel structural and functional studies of the BPV1 E6 in complex with its preferential target motif.     

Pancreatic lipase inhibition activity of trilactone terpenes of Ginkgo biloba

The prevalence of obesity is increasing at an alarming rate, but, unfortunately, only a few drugs are currently available on the market. In the present study, the methanolic extract of Ginkgo biloba L. (Ginkgoaceae) was investigated as an inhibitor of pancreatic lipase (PL) in an attempt to explain its hypolipidaemic activity. In vitro assay of G. biloba leaves extract revealed a substantial PL inhibition activity (IC(50)?=?16.5 μg/mL). Further investigation was performed by employing theoretical docking simulations and experimental testing to uncover the active constituents responsible for G. biloba anti-lipase activity. Virtually, terpene trilactones, including ginkgolides and bilobalide, were found to fit within the binding pocket of PL via several attractive interactions with key amino acids. Experimentally, ginkgolides A, B, and bilobalide were found to inhibit PL significantly (IC(50)?=?22.9, 90.0, and 60.1 μg/mL, respectively). Our findings demonstrated that the hypolipidaemic effects of G. biloba extract can be attributed to the inhibition of PL by, at least in part, terpene trilactones. In conclusion, this work can be considered a new step towards the discovery of new natural safe hypolipidaemic PL inhibitors.     

Oxidative damage induced by chromium (VI) in rat erythrocytes: protective effect of selenium

Excess chromium (Cr) exposure is associated with various pathological conditions including hematological dysfunction. The generation of oxidative stress is one of the plausible mechanisms behind Cr-induced cellular deteriorations. The efficacy of selenium (Se) to combat Cr-induced oxidative damage in the erythrocytes of adult rats was investigated in the current study. Female Wistar rats were randomly divided into four groups of six each: group I served as controls which received standard diet, group II received in drinking water K₂Cr₂O₇ alone (700 ppm), group III received both K₂Cr₂O₇ and Se (0.5 Na₂SeO₃ mg/kg of diet), and group IV received Se (0.5 mg/kg of diet) for 3 weeks. Rats exposed to K₂Cr₂O₇ showed an increase of malondialdehyde and protein carbonyl levels and a decrease of sulfhydryl content, glutathione, non-protein thiol, and vitamin C levels. A decrease of enzyme activities like catalase, glutathione peroxidase, and superoxide dismutase activities was also noted. Co-administration of Se with K₂Cr₂O₇ restored the parameters cited above to near-normal values. Therefore, our investigation revealed that Se was a useful element preventing K₂Cr₂O₇-induced erythrocyte damages.     

Morphologic and molecular data suggest that Lynnella semiglobulosa n. g., n. sp. represents a new family within the subclass Choreotrichia (Ciliophora, Spirotrichea)

The morphology, morphogenesis, and phylogeny of an undescribed oligotrich sensu lato (s. lat.) ciliate, Lynnella semiglobulosa n. g., n. sp., found in Daya Bay, southern China, were investigated. This species shares some features with both oligotrichs sensu stricto and choreotrichs, but most morphological and morphogenetic characters as well as the phylogenetic analysis suggest that it should be assigned into subclass Choreotrichia temporarily. Lynnella semiglobulosa is distinguished from members of all known genera and families of the subclass Choreotrichia by a unique combination of characteristics of the buccal and somatic ciliatures. Thus, a new family Lynnellidae n. fam. and a new genus Lynnella n. g. are proposed for it. The new family is distinguished by an open adoral zone of membranelles (AZM) in which, however, there are no ventral membranelles; the distal and proximal portions of the new adoral zone lie close to each other forming an open circle in stomatogenesis. The new genus Lynnella is characterized by possessing two longitudinally oriented somatic kineties, one dorsal and one ventral, several proximal membranelles progressively lengthened toward the proximal end of adoral zone, and two macronuclear nodules. In phylogenetic analyses based on small subunit rRNA gene sequences, L. semiglobulosa clustered basally to all choreotrichs, but with relatively weak support; nevertheless, the possibility of a relationship with the subclass Oligotrichia was not rejected by the approximately unbiased nor Shimodaira-Hasegawa test. Based on morphological, morphogenetic, and molecular evidence of L. semiglobulosa, it is confirmed that the open AZM should be a plesiomorphic character of oligotrichs s. lat. as suggested previously.     

Synthesis and in vitro behavior of β-TCP zirconia/polymeric biocomposites for bio-applications

Novel biocomposites were fabricated by impregnating β-tricalcium phosphate (β-TCP)/zirconia particles into the polymers matrix. The composite materials were characterized using thermo-gravimetric analysis (TGA), X-ray diffraction (XRD), Fourier Transform Infrared (FT-IR) analyzes and Scanning Electron Microscopy (SEM). The results confirmed the conversion of hydroxyapatite (HA) to β-TCP at a sintering temperature of 1150 °C with or without zirconia powder. The in vitro behavior was assessed via measurement of calcium and phosphorus ions in SBF (simulated body fluid). FT-IR and SEM of the composites were performed pre and post immersion in SBF. The results prove that the bone like apatite layer formation was enhanced on the β-TCP-Z20/polymeric composite surface more than that on the β-TCP-Z10/polymeric composite. Therefore, the data confirmed that zirconia plays an important role in the enhancement of the apatite formation. The conclusions proved that the β-TCP-Z20/polymeric biocomposites, containing 20% of zirconia, are promising for bone remodeling applications.