Current Issue : April - June Volume : 2012 Issue Number : 2 Articles : 8 Articles
The cells that retain their proliferative capacity thought out life are regarded as stem cells.According to differentiation potential they can be classified as pluripotent, multipotent, unipotent cells. Major potential sources of stem cells are blastocyst embryos, foetal tissues, umbilical cord blood, and adult tissues. ES cells are an extra ordinary class of stem cells that can proliferate indefinitely in culture, as they posses very high developmental potential. Cord blood, donated by mothers after the birth of their children, has become an accepted source of related and unrelated hematopoietic stem cells for marrow reconstitution. Adult stem cells also referred to as somatic stem cells or mesenchymal stem cells are those mature, adult cells that are undifferentiated and found in a specific tissue or organ. Stem cells derived from adipose tissue and bone marrow show great promise as an alternate source of cells for adipose tissue engineering. The purified muscle-derived cells can differentiate into osteogenic lineages and proceed to mineralization and possible bone tissue formation. This concluded that the muscle tissue may become a valuable resource for the isolation of osteoprogenitor cells capable of improving bone healing. Adult neural stem cells (aNSCs) represent an attractive source for the production of specific types of neurons in degenerative CNS diseases and for the development of new regenerative gene therapies. Embryonic and adult stem cells also appear to be the precursors of hair cells the bone marrow derived mesenchymal stem cells/cord blood stem cells may also differentiate into hair cells when grown in suitable medium condition to restore the nearly normal hearing. A potential problem with stem cell therapy is immune rejection of transplanted stem cells. It has been suggested that this might be avoided using therapeutic cloning....
Fungi can cause severe invasive infections especially in the immunocompromised host. Patient populations at risk are increasing due to ongoing developments in cancer treatment and transplantation medicine. Only limited diagnostic tools and few antifungals are available, rendering a significant number of invasive fungal infections life threatening. To reduce mortality rates, a better understanding of the infection processes is urgently required. Bioluminescence imaging (BLI) is a powerful tool for such purposes, since it allows visualisation of temporal and spatial progression of infections in real time. BLI has been successfully used to monitor infections caused by various microorganisms, in particular bacteria. However, first studies have also been performed on the fungi Candida albicans and Aspergillus fumigatus. Although BLI was, in principle, suitable to study the infection process, some limitations remained. Here, different luciferase systems are introduced, and current approaches are summarised. Finally, suggestions for further improvements of BLI to monitor fungal infections are provided....
The antimicrobial activity of the oil extracted with n-hexane from the seeds of\r\nMoringa peregrina was tested against Staphylococcus aureus, S. epidermidis,\r\nPseudomonas aeruginosa, Escherichia coli, Enterobacter cloacae, Klebsiella pneumoniae,\r\nCandida albicans, C. tropicalis and C. glabrata. The oil proved effective against all of the\r\ntested microorganisms. Standard antibiotics (netilmycin, 5-flucytocine, intraconazole and\r\n7-amino-4-methylcoumarin-3-acetic acid) were used for comparison. The resistance to\r\noxidation of the extracted seed oil was also determined....
Cryptococcosis is a life-threatening fungal disease that infects around one million people each year. Establishment and progression\r\nof disease involves a complex interplay between the fungus and a diverse range of host cell types. Over recent years, numerous\r\ncellular, tissue, and animal models have been exploited to probe this host-pathogen interaction. Here we review the range of\r\nexperimental models that are available for cryptococcosis research and compare the relative advantages and limitations of the\r\ndifferent systems....
Staphylococcus aureus possesses three MsrA enzymes (MsrA1, MsrA2, MsrA3) that reduce the S-epimer of methionine sulfoxide\n(MetO) and an MsrB enzyme that reduces R-MetO. The four msr genes are expressed from three different promoters. The\nmsrA1/msrB genes are coexpressed. To determine the expression pattern of msr genes, three independent reporter strains were\nconstructed where msr promoter was cloned in front of a promoterless lacZ and the resulting construct was integrated in the\nchromosome. Using these strains, it was determined that the msrA1/B expression is significantly higher in S. aureus compared to\nmsrA2 or msrA3. Expression of msrA1/B was highest during stationary phase growth, but the expression of msrA2 and msrA3 was\nhighest during the early to midexponential growth phase. Expression of msrA1/B was induced by oxacillin and the expression of\nmsrA3 was upregulated by salt. Expression of msrA2 remained unchanged under all tested conditions....
Most of the fungal species that infect humans can grow in more than one morphological form but only a subset of pathogens produce\r\nfilamentous hyphae during the infection process. This subset is phylogenetically unrelated and includes the commonly carried\r\nyeasts, Candida albicans, C. dubliniensis, andMalassezia spp., and the acquired pathogens, Aspergillus fumigatus and dermatophytes\r\nsuch as Trichophyton rubrum and T. mentagrophytes. The primary function of hypha formation in these opportunistic pathogens is\r\nto invade the substrate they are adhered to, whether biotic or abiotic, but other functions include the directional translocation between\r\nhost environments, consolidation of the colony, nutrient acquisition and the formation of 3-dimensional matrices. To support\r\nthese functions, polarised hyphal growth is co-regulated with other factors that are essential for normal hypha function in vivo....
Amphipathic a-helical antimicrobial peptides comprise a class of broad-spectrum agents that are used against pathogens. We\r\ndesigned a series of antimicrobial peptides, CP-P (KWKSFIKKLTSKFLHLAKKF) and its derivatives, and determined their\r\nminimum inhibitory concentrations (MICs) against Pseudomonas aeruginosa, their minimum hemolytic concentrations (MHCs)\r\nfor human erythrocytes, and the Therapeutic Index (MHC/MIC ratio). We selected the derivative peptide K11, which had the\r\nhighest therapeutic index (320) among the tested peptides, to determine the MICs against Gram-positive and Gram-negative\r\nbacteria and 22 clinical isolates including Acinetobacter baumannii, methicillin-resistant Staphylococcus aureus, Pseudomonas\r\naeruginosa, Staphylococcus epidermidis, and Klebsiella pneumonia. K11 exhibited low MICs (less than 10 �µg/mL) and broadspectrum\r\nantimicrobial activity, especially against clinically isolated drug-resistant pathogens. Therefore, these results indicate\r\nthat K11 is a promising candidate antimicrobial peptide for further studies....
The objective of this study was to investigate the in vivo activity of the lantibiotic lacticin 3147 against the luminescent\nStaphylococcus aureus strain Xen 29 using a murine model. Female BALB/c mice (7 weeks old, 17 g) were divided into groups\n(n = 5) and infected with the Xen 29 strain via the intraperitoneal route at a dose of 1 Ã?â?? 106 cfu/animal. After 1.5 hr, the animals\nwere treated subcutaneously with doses of phosphate-buffered saline (PBS; negative control) or lacticin 3147. Luminescent imaging\nwas carried 3 and 5 hours postinfection.Mice were then sacrificed, and the levels of S. aureus Xen 29 in the liver, spleen, and kidneys\nwere quantified. Notably, photoluminescence and culture-based analysis both revealed that lacticin 3147 successfully controlled\nthe systemic spread of S. aureus in mice thus indicating that lacticin 3147 has potential as a chemotherapeutic agent for in vivo\napplications....
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