The survey of ectoparasites on two species of Triakids (Mustelus mustelus and M. punctulatus) sharks from Tunisian coasts

Between 2018 and 2020, 696 fish belonging to two species of sharks from the Family Triakidae (Mustelus mustelus and M. punctulatus) were collected from the coasts of Tunisia and inspected for parasites. Six copepod taxa (Perissopus dentatus Steenstrup & Lütken, 1861, Eudactylinella alba Wilson, 1932, Kroyeria lineata Van Beneden, 1853, Nesippus orientalis Heller, 1865 and Lernaeopoda galei Krøyer, 1837, Kroyeria sp.), four isopod species (Anilocra physodes (Linnaeus, 1758), Emetha audouini (H. Milne Edwards, 1840), Ceratothoa parallela (Otto, 1828) and Ceratothoa oestroides (Risso, 1816)) and two monogenean species (Erpocotyle sp1. And Erpocotyle sp2) were collected. A large number of global host records was reported, including the occurrence of E. audouini on M. mustelus and of Erpocotyle sp.2 on M. punctulatus. The study of the diversity of parasites per host species revealed that M. mustelus had a higher parasitic richness compared to M. punctulatus. In this study, it was provided for the first records on ectoparasites on Triakidae sharks from Tunisian coasts and their infection indices.     

In Situ Biosurfactant Production by Bacillus Strains Injected into a Limestone Petroleum Reservoir

Biosurfactant-mediated oil recovery may be an economic approach for recovery of significant amounts of oil entrapped in reservoirs, but evidence that biosurfactants can be produced in situ at concentrations needed to mobilize oil is lacking. We tested whether two Bacillus strains that produce lipopeptide biosurfactants can metabolize and produce their biosurfactants in an oil reservoir. Five wells that produce from the same Viola limestone formation were used. Two wells received an inoculum (a mixture of Bacillus strain RS-1 and Bacillus subtilis subsp. spizizenii NRRL B-23049) and nutrients (glucose, sodium nitrate, and trace metals), two wells received just nutrients, and one well received only formation water. Results showed in situ metabolism and biosurfactant production. The average concentration of lipopeptide biosurfactant in the produced fluids of the inoculated wells was about 90 mg/liter. This concentration is approximately nine times the minimum concentration required to mobilize entrapped oil from sandstone cores. Carbon dioxide, acetate, lactate, ethanol, and 2,3-butanediol were detected in the produced fluids of the inoculated wells. Only CO₂ and ethanol were detected in the produced fluids of the nutrient-only-treated wells. Microbiological and molecular data showed that the microorganisms injected into the formation were retrieved in the produced fluids of the inoculated wells. We provide essential data for modeling microbial oil recovery processes in situ, including growth rates (0.06 ± 0.01 h⁻¹), carbon balances (107% ± 34%), biosurfactant production rates (0.02 ± 0.001 h⁻¹), and biosurfactant yields (0.015 ± 0.001 mol biosurfactant/mol glucose). The data demonstrate the technical feasibility of microbial processes for oil recovery.     

Mise en évidence d’une flore oxfordienne dans le Sud-Est de la Tunisie : intérêts stratigraphique et paléoécologique

The Late Jurassic - Early Cretaceous series encountered in South-East Tunisia, formely considered globally as Purbecko-Wealdian in age, has the most complete palaeobotanical record of all North-Gondwana. Thanks to the stratigraphical results of the last years and to new field researches, it was possible, for the first time, to evidence an Oxfordian flora at the base of this series (Bir Miteur Formation). This flora, constituted of impressions and axes of Pteridophytes and Gymnosperms, is encountered within different types of plant-bearing levels. The study of deposit facies and sequential analysis of this Oxfordian formation allowed the identification of corresponding sedimentary environments and to infer their palaeoecological meaning. The discovery of exceptional specimens provided new informations about the general morpho-anatomy of Alstaettia, a very peculiar tree fern of a now extinct type. This Oxfordian flora is an interesting key-point in the evolution of North-Gondwanian flora at the Jurassic/Cretaceous transition.     

Malyngamide 4, a new lipopeptide from the Red Sea marine cyanobacterium Moorea producens (formerly Lyngbya majuscula)

In our continuing effort to discover new drug leads from Red Sea marine organisms, a sample of the marine cyanobacterium Moorea producens (previously Lyngbya majuscula) was investigated. Bioassay-directed purification of a tumor cell-growth inhibitory fraction of the organic extract of the Red Sea cyanobacterium afforded a new compound, malyngamide 4 (1), together with five previously reported compounds, malyngamide A (2) and B (3), (S)-7-methoxytetradec-4(E)-enoic acid (lyngbic acid, 4), aplysiatoxin (5) and debromoaplysiatoxin (6). Assignment of the planar structures of these compounds was based on extensive analysis of one- and two-dimensional NMR spectra and high-resolution mass spectrometric data. The isolated compounds were evaluated for their inhibitory activity against three cancer cell lines. In addition, the antibacterial activity of the compounds against Mycobacterium tuberculosis H₃₇Rv ATCC 27294 (H₃₇Rv) was evaluated. Lyngbic acid (4) was the most active against M. tuberculosis, while malyngamides 4 (1) and B (3) moderately inhibited the cancer cell lines. The other compounds were deemed inactive at the test concentrations.     

Isosteric ramatroban analogs: selective and potent CRTH-2 antagonists

The chemoattractant receptor-homologous molecule expressed on T(H)2 cells (CRTH-2), also found on eosinophils and basophils, is a prostaglandin D2 receptor involved in the recruitment of these cell types during an inflammatory response. In this report, we describe the synthesis and optimization of a ramatroban isostere that is a selective and potent antagonist of CRTH-2 which may be useful in the treatment of certain diseases.     

Expression, purification, and characterization of His-tagged Staphylococcus xylosus lipase wild-type and its mutant Asp 290 Ala

The gene encoding the extracellular lipase of Staphylococcus xylosus (SXL) was cloned using PCR technique. The sequence corresponding to the mature lipase was subcloned in the pET-14b expression vector, with a strong T7 promoter, to construct a recombinant lipase protein containing six histidine residues at the N-terminal. High level expression of the lipase by Escherichia coli BL21 (DE3) cells harbouring the lipase gene containing expression vector was observed upon induction with 0.4 mM IPTG at 37 degrees C. One-step purification of the recombinant lipase was achieved with Ni-NTA resin. The specific activity of the purified His-tagged SXL was 1500 or 850 U/mg using tributyrin or olive oil emulsion as substrate, respectively. It has been proposed that the region near the residue Asp290 could be involved in the selection of the substrate. Therefore, we also mutated the residue Asp 290 by Ala using site-directed mutagenesis. The mutant SXL-D290A was overexpressed in E. coli BL21 (DE3) and purified with the same nickel metal affinity column. The specific activity of the purified His-tagged SXL-D290A mutant was 1000 U/mg using either tributyrin or olive oil emulsion as substrate. A comparative study of the wild type (His(6)-SXL) and the mutant (His(6)-SXL-D290A) proteins was carried out. Our results confirmed that Asp290 is important for the chain length specificity and catalytic efficiency of the enzyme.     

Theoretical investigations on the mechanistic pathway of the thermal rearrangement of substituted N-acyl-2,2-dimethylaziridines

The mechanism of the thermal rearrangement of substituted N-acyl-2,2-dimethylaziridines 1 has been studied using quantum chemistry methods. Geometries of reactants, transition states and products have been optimized at the B3LYP/6-311++G(2d,2p) level. Relative energies for various stationary points have been determined and reaction identified by IRC calculations. The results show that thermal rearrangements occur in three ways. Firstly, the transition state TS ₁ in which a hydrogen atom of methyl groups migrates from primary carbon to oxygen of amid group to give the N-methallylamide 2. The second is via the transition state TS ₂ in which the attack of oxygen to the tertiary carbon yields the oxazoline 3. The third is via the transition state TS ₃ in which a hydrogen migrate from the secondary carbon to oxygen to give the vinylamide 4. In order to get insights into the factors determining the exact nature of its interactions with electrophiles, the application of reactivity parameters derived from density functional theory in a local sense, in particular the softness and Fukui function, to interpret and predict the mechanisms of the thermal decomposition of the N-acyl-2,2-dimethylaziridines 1, has been discussed.     

Endoscopic Management of Genitourinary Foreign Bodies

Retrieval of foreign bodies from the genitourinary system, most commonly inserted for sexual satisfaction or as a result of a psychiatric illness, can pose a significant surgical challenge. Due to their breadth of size, shape, and location within the genitourinary system, endoscopic management can be difficult. Here, we review the management of four cases of foreign object insertion into the genitourinary system and their outcomes and management.Key words: Foreign body insertion, Sounding, Genitourinary foreign object, Endoscopic extractionForeign objects within the genitourinary tract present a challenging urologic finding due to the diversity and breadth of presentation. Although many objects are easily removed, more complex approaches may be required depending on the size, shape, and location of the object.^1,2 In this case series, we discuss the endoscopic management of four patients who presented with foreign bodies in the urethra. Two patients inserted beads into their genitourinary tract for the purpose of sexual stimulation and two patients had a history of psychiatric illness with multiple insertions of a diverse range of foreign objects. In all four cases, endoscopic management was successful in removing the objects, with no need for an open approach such as perineal urethrotomy or open cystostomy. In case 2, in which an open approach was attempted at an outside hospital, this open approach was associated with intraoperative complications.     

Synthesis and DNA Binding Properties of a New Benzo[f]Imidazo[1,5b]-Isoquinoline-Butan-1,2-Diol Derivative

A benzo[f]imidazo[1,5b]-isoquinoline derivative 4 with a 1,2-butandiol linker was prepared by reaction of a trimethylsilylated 5-naphthylidenehydantoin 3 with a 2,3-dideoxy-D-glycero-pentafuranoside 2 in 22% yield. After deprotection, the resulting compound 5 was converted to a DMT protected phosphoramidite building block 7 for standard DNA synthesis. DNA/DNA, DNA/RNA duplexes with 5 inserted as bulges were destabilized, except when the new amidite was used for the synthesis of a zipping duplex.