Mohammad Abdul Rahmman Al-Maeni Mohammad Abdul Rahmman Al-Maeni

Abstract

Alteration of repeat tract length within the SSR of phase variable genes may enhance the persistence of isolates within their host for a long time (a period of months) (Alamro et al.,2014). Alamro et al. (2014) showed there was trend towards selection for OFF state or low expression for five phase variable genes (opc, hmbr, nadA, nalP, hpuAB) in three carriers (V54, V124 and V64) within strains belonging into CC174 and CC167 in first, second and third time points. He concluded that the selection for low or OFF state helped N. meningitidis to persist for a long time (Alamro et al., 2014). The current study aimed to detect the alteration in the repeat tracts of the same five variable genes within the previous three carriers (V54, V124, and V64) but for other strains belonging to CC22, CC269, and CC198 at the fourth time point. There was also a trend towards selection for an OFF state or low expression for three genes which are (opc, hpuAb, nalP) with 2/3 (66.6%) carriers while hmbr gene showed ON state in all carriers (100%). This indicates that antibodies formed against (opc, HpuAb, nalP) genes in strains belonging to CC174 and CC167 in first, second and third time points were able to enhance immunization against the isolates in the current study for CC269 and CC22 resulting in the selection for the OFF state or low expression. Conversely, antibodies formed against hmbr gene in the previous time points on isolates within the CC167 may not show immunization against hmbr gene in the isolates of current study CC22, CC198 and CC269 and so the gene stayed in the ON state. Interestingly, the nadA gene was missing from isolates under the current study. These results may reflect important aspects in the vaccination program especially as nadA is one of the component of Bexsero vaccine. Keywords: Phase variation, SSR, Neisseria meningitides.

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Abstract

Important points were concluded from this analysis related with the presence of the same variable CEs within multiple isolates with different time points being under the selection and the location of SNPs within the conserved functional pattern of CEs. In the 40 isolates, 9 out of 39 variable CEs conducted with multiple isolates, each one affected around 20% or more of population. In the same way, the presence same variable CEs within multiple isolates belonging to same CCs or different CCs of 25 pair isolates detected in 12 out of 137 variable CEs, each one affected around 10% or more out of 25 pair isolates. Interestingly, some CEs showed variation within promoters or IHF patterns or were inserted inside the genes, and were associated with genes that coded mainly for different enzymes within metabolism scheme or transporters within outer membrane scheme in both 40 and 25 pair isolates. This variation may change the level of transcription of genes belonging into previous mentioned schemes and this altered expression may help N. meningitidis to resist the immune system. There were 6 out of 39 and 15 out of 137 variable CEs that showed variation within the conserved functional pattern in 40 isolates and 25 pair isolates respectively. Another function of CEs is as a source of variation in N. meningitidis. Keywords: CEs, N. meningitidis, Genome variation.

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Abstract

A crucial area of research in nanotechnology is the formation of environmentally benign nanoparticles. Both unicellular and multicellular play an important role in synthesis nanoparticles through the production of inorganic materials either intracellularly or extracellularly. The agents (pigments, siderophores, cell extracted metabolites and reducing compounds) were used to prepare silver nanparticles with different sizes and shapes. The color variations (dark yellow, slightly dark yellow and golden yellow) arising from changes in the composition, size, and shape of nanoparticles, surrounding medium can be monitored using UV-visible spectrophotometer. These effects are due to the phenomena called surface plasmon resonance. The silver nanoparticles have Plasmon resonances ranged between (390, 383 and 365) nm which they are among the limitation of silver nanoparticles (360 – 420 nm). AFM analysis of Ag NP’s showed partially purified big triangular Ag NP having edge length around ~1. mm. Hexagonal particles on the background of a matrix made up of some molecules which may be metabolites products are found. Small spherical nanoparticles embedded in some kind of matrix indicate that this molecule acts as capping agent, which inhibits further growth of nanoparticles. Also ribbons like structures of width around 50 nm which are intertwined are the noble and rare structures which are synthesized by this method. MIC of silver Nanoparticles for. E coli, ranges between 80-90 µg/ml.., Serrtia, ranges between 50-60 µg/ml and Shagilla, ranges between 90-100 µg/ml. Keywords: Metabolites product of microorganisms, silver nanoparticles.

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