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Two types of larval electroreceptors, type A and B, are described in the epidermis of the head of larvae of three mormyrid species, Campylomormyrus cassaicus, Mormyrus rume proboscirostris and Pollimyrus isidori, bred in captivity. In each of these electroreceptor organs, a single sensory cell is found inside an intraepidermal cavity, sitting on a platform of accessory cells. The cavity is filled with microvilli originating both from the sensory cell and from the epidermal covering cells lining the intraepidermal cavity. These two types of tuberous larval electroreceptors differ in their distribution in the epidermis of the head, in the composition of their accessory cells, and by their innervation. The innervation found in type B organs is similar to that already described for electroreceptors of adult mormyrids. The sensorineural junction is composed of primary afferent terminal boutons, which contact the base of the sensory cell. Opposite each terminal bouton, a ribbon-like synaptic bar surrounded by vesicles is found in the cytoplasm of the sensory cell. In contrast, the base of the sensory cell in type A larval electroreceptors is not contacted by nervous terminal boutons, but instead forms closed appositions with specialized prolongations of accessory cells of the platform. The base of the sensory cell presents membrane evaginations, with hemispheric synaptic structures and few synaptic vesicles. These two types of electroreceptor organs degenerate at the time of the degeneration of the larval electric organ and the functional differentiation of the adult electric organ. The functional role of two tuberous electroreceptor types is examined.

Background and Objective: With the emergence of antibiotic resistance and the hospital acquired infection, the interest for antimicrobial agents has recently increased again in public health. Copper is recommended as a supplementary method of increasing biological safety in the hospital environment. The objective of this study was to determine the antibacterial activity of copper sulfate salts on strains of bacterial pathogens isolated from different clinical pictures in different health establishment in Algeria. Methods: A total of 25 different bacterial isolates (16 Enterobacteriaceae, 5 Staphylococci, and 4 Pseudomonas) were tested for susceptibility to copper sulfate using minimum inhibitory concentration (MIC-Cu) and minimum bactericidal concentrations (MBC-Cu) determinations. All isolates were also tested for susceptibility to six antibiotics. Results: Antibiotic susceptibility studies revealed that 100% of isolates were resistant to one or more antibiotics. Fifty two percent of isolates were very susceptible to copper sulfate, with MICs ranging from 100 to 200 µg/ml. MBC-Cu = 1600 μg/ml showed the best bactericidal effect against the great majority of studied bacteria (52%). A good bactericidal activities of copper sulfate were recorded against Proteus vulgaris and Staphylococcus aureus (MBC/MIC=1). The Gram-negative bacteria isolates which were copper resistant also showed a high resistance to chloramphenicol (r=0.78) and Trimethoprime (r=0.61). Furthermore, the strains that were no-susceptible to three different antimicrobial classes (Escherichia coli, Staphylococcus saprophyticus) were not resistant to copper sulfate. Conclusion: Copper sulfate salts has significant antibacterial activity against multi-drug resistant nosocomial pathogens. doi: https://doi.org/10.12669/pjms.35.5.336 How to cite this:Benhalima L, Amri S, Bensouilah M, Ouzrout R. Antibacterial effect of copper sulfate against multi-drug resistant nosocomial pathogens isolated from clinical samples. Pak J Med Sci. 2019;35(5):---------.  doi: https://doi.org/10.12669/pjms.35.5.336 This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Succession in bloom-forming cyanobacteria belonging to distant functional groups in freshwater ecosystems is currently an undescribed phenomenon. However in the Hammam Debagh reservoir (Algeria), P. rubescens and Microcystis sp. co-occur and sometimes proliferate. With the aim of identifying the main factors and processes involved in this unusual cohabitation, water samples were collected monthly from February 2013 to June 2015 at the subsurface at four sampling stations and along the entire water column at one sampling station. In addition, the composition of the cyanobacterial communities was estimated by Illumina sequencing of a 16S rRNA gene fragment from samples collected over one year (October 2013-November 2014). This molecular approach showed that the Hammam Debagh reservoir displays high species richness (89 species) but very low diversity due to the high dominance of Microcystis in this community. Furthermore, it appears that Planktothrix rubescens and Microcystis sp. coexisted (from September to January) but proliferated alternately (Spring 2015 for P. rubescens and Spring 2014 and Autumn 2014/2015 for Microcystis). The main factors and processes explaining these changes in bloom-forming species seem to be related to the variation in the depth of the lake during the mixing period and to the water temperatures during the winter prior to the bloom season in spring.

The distribution and some immunohistochemical aspects of the taste buds and free neuromasts of the blind cave fish Astyanax jordani were investigated using serial sections of whole fish. Taste buds are restricted to the skin of the lips and the lower jaw. Neuromasts are widely distributed over the whole epidermis except the lips and are particularly numerous in the opercular region and the caudal fin; they are absent from all other fins. The histological structure of the taste buds and the free neuromasts is similar to that described in other fish. The former are composed of two types of cells. The free neuromast, as seen under the electron microscope, is also constituted by two types of cell: dark supporting cells and clear sensory cells whose basal cytoplasm contains presynaptic bodies. Immunohistochemical results obtained with the peroxidase antiperoxidase method revealed the presence of different peptides in the taste buds and the free neuromasts. The former contain substance P (SP) and enkephalins (leu- and metenkephalin); the latter contain SP and leuenkephalin, but no metenkephalin. These peptides are localized in the cytoplasm of the accessory and sensory cells but not in the nervous fibres. None of these peptides occur in the olfactory epithelium of A.jordani. These immunohistochemical results raise the question of whether SP, leuenkephalin or metenkephalin play a role in transmission between the sensory cells and the afferent fibre.

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