Iranian Journal of Biotechnology
Volume:9 Issue: 3, Summer 2011

Phenylketonuria (PKU) is the most common autosomal recessive disorder of amino acid metabolism. The disease is caused mainly by mutations in the phenylalanine hydroxylase (PAH) gene, encoding phenylalanine hydroxylase (PAH) enzyme. The PAH enzyme deficiency results in the elevation of phenylalanine in the blood, which may cause severe irreversible mental retardation in the affected individuals. More than 500 different disease causing mutations have been identified in the PAH gene. Direct and indirect molecular approaches have been developed for carrier detection and prenatal diagnosis of PKU disease. Population distribution of the PAH gene mutations and the PKU disease varies in different countries. In view of relatively high prevalence of the disease in Iranian population, investigations toward the elucidation of molecular aspects of the disease were required. In the present article, clinical and molecular basis of the PKU disease, with emphasis on the studies performed in Iranian population, were reviewed.

A total of twenty-two strict anaerobic and Gram-positive Bifidobacteria, identified as B. adolescentis, B. pseudocatenulatum, or B. longum, were isolated from healthy adult Koreans. We here investigated the cell morphology, antimicrobial resistance patterns to novel antibiotics and genotypic differentiation of Bifidobacteria assessing repetitive DNA element PCR (rep-PCR) fingerprinting using the BOXA1R primer at the species level. All Bifidobacterium spp., except B. adolescentis SPM1005 and B. longum SPM1205, formed round and convex colonies. All B. adolescentis, B. pseudocatenulatum, and B. longum were opaque white glossy in colony color, and short, long, and irregular rods in morphological shape. In addition, all B. adolescentis, B. pseudocatenulatum, and B. longum formed a variety of shapes ranging from rods to V-shaped, Y-shaped, clubbed rods, or irregular. All Bifidobacterium spp., except B. adolescentis SPM0214, were sensitive to daptomycin (DAP), linezolid (LIN), and tigecycline (TIG). B. adolescentis SPM0214 was resistant to DAP. Genomic fingerprinting patterns of B. adolescentis, B. pseudocatenulatum, and B. longum were diverse and different from those of the KCTC strain. The band size of B. adolescentis, B. pseududocatenulatum, and B. longum varied from 3.0 kb to 300 bp, 2.0 kb to 200 bp, and 2.0 kb to 500 bp, respectively. In conclusion, twenty-two strains of B. adolescentis, B. pseudocatenulatum, and B. longum isolated from healthy adult Koreans were very diverse in both phenotype and genotype. Moreover, this diversity of phenotype and genotype may support that health promoting effects of individual strain of Bifidobacterium spp. human isolates could be different and specific even within same species.

Clostridium Botulinum Type E neurotoxin heavy chain consists of two domains: the translocation domain as the N-terminal half and the binding domain as the C-terminal half (Hc). One effective way to neutralize botulinum neurotoxin is to inhibit binding of this toxin to neuromuscular synapses with antibodies against binding domain. Two synthetic genes, coding for Hc (the full length binding domain) and the c-terminal quarter of binding domain (HcQ), were cloned in pET-28a vector and over-expressed in E. coli BL21 (DE3) cells. These recombinant proteins were purified by affinity Ni-NTA column (under native condition). Mice were vaccinated with 2 mg of purified proteins, respectively; at step one with complete adjuvant, steps two and three with incomplete adjuvant and step four only with phosphate buffered saline (PBS). Enzyme-linked immunosorbent assay (ELISA) has been performed with mice serum samples 14 days following their third and final vaccination. Binding activity of the purified proteins to ganglioside and synaptotagmin II was analyzed by ELISA. The results showed that HcQ and Hc could bind with ganglioside. Based on challenge experiments it was revealed that HcQ, Hc and BoNT/E toxoid could give protections in mice challenged with 102, 104 and 105 minimum lethal dose (MLD) dose of BoNT/E.

This study investigates the production of crude Ca-independent and low pH active a-amylase by Bacillus sp. KR-8104 in submerged fermentation (SmF) and solid-state fermentation (SSF) systems. Different parameters were evaluated in each system using “one factor at a time” approach to improve the production of enzyme. The results showed that in the SmF the maximum enzyme production was achieved in culture medium that contained dextrin as a carbon source, as well as yeast extract and meat extract as nitrogen sources incubated at 37ºC and 180 rpm for 48 h. While SSF of Bacillus sp. KR-8104 using wheat bran (WB) as a substrate showed that using tap water or distilled water as a moisturizing agent, a substrate-water ratio of 1:1.5 (w/v) and incubation at 37ºC for 48 h gave the maximum a-amylase production. From different extraction medium examined in this study 0.1% (v/v) aqueous mixture of Tween 20 and distilled water illustrated maximum results (~100 U/g).

Partial nitrification was reported to be technically feasible and economically favorable, especially for wastewater with high ammonium concentration or low C/N ratio. In this study, the effect of dissolved oxygen (DO) and influent ratio of chemical oxygen demand to nitrogen (COD/N) ratio on biological nitrogen removal from synthetic wastewater was investigated. Experiments were conducted in moving bed biofilm reactors (MBBRs) on partial nitrification process in pilot-plant configuration for 300 days. DO levels were changed from 0.04 to 0.12 and 0.42 to 3.4 mg/l in the anoxic (R1) and aerobic (R2) reactors, respectively. The optimum DO for partial nitrification was between 1-1.5 mg/l in the aerobic reactor (R2). Influent COD/N ratios between 20 and 2 g COD/g-N were tested by changing the nitrogen loading rate (NLR) supplied to the pilot plant. During operational conditions when the DO concentration in aerobic reactor was above 1 mg/l, near complete organic carbon removal occurred in the total MBBRs system. The effluent total nitrogen concentration in the operational conditions (1.7-2.1 mg O2/l and NH+4-N=35.7 mg N/l) was obtained in the range of 0.85-2 mg/l. The highest nitrite accumulation (50%-52%) took place at the DO concentration of 1-1.5 mg/l and increased with decreasing COD/N ratio in aerobic reactor (R2). This study showed that the average nitrification rate at various COD/N ratios is about 0.96 gN/m2 per day while the maximum nitrification rate is about 2 gN/m2 per day at COD/N ratios lower than 6. The experimental COD/N ratio for denitrification was close to complete sum of NO2- and NO3- (NOx) removal efficiency (about 99%) at COD/N ratio equal 14 in the operational conditions in the anoxic reactor (R1).

A rapid in vitro propagation system has been established from mature shoot tip and nodal segments of a highly valuable medicinal plant Alternanthera sessilis (L.). The explants were cultured on Murashige and Skoog’s medium augmented with different concentrations and combinations of plant growth regulators for shoot bud initiation and multiplications. For shoot tip, highest frequency of shoot proliferation (94.3 ± 0.43) and maximum number per explants (23.4 ± 0.38) was observed in Murashige and Skoog’s medium augmented with 2.0 mg/l of 6-Benzyl Amino Purine. For nodal segments, highest frequency of shoot proliferation (90.4 ± 0.82) and maximum number (15.2 ± 0.63) per node was observed in Murashige and Skoog’s medium augmented with 1.5 mg/l of 6-Benzyl Amino Purine. Maximum percentage of callus formation (Leaves- 92.4 ± 0.61; Inter-nodal -88.9 ± 0.83) was obtained on Murashige and Skoog’s basal medium supplemented with 3% and 2, 4-Dichlorophenoxy acetic acid 2.0 mg/l. Highest efficiency (97.4 ± 1.36) of rooting and maximum number (6.3 ± 0.42) of rootlet per shoot let was achieved on half strength Murashige and Skoog’s medium fortified with 3 mg/l of Indole-3-Butyric acid. Regenerated plants were successfully transferred to field (78%).

The full-length coat protein gene of Grapevine fanleaf virus (GFLV) isolates from Iran was characterized by reverse transcription polymerase chain reaction (RT-PCR) and sequencing. The expected 1515 bp coat protein (CP) gene amplicon was obtained for 16 isolates out of 89 that were identified by double antibody sandwich enzyme-linked immunesorbent assay (DAS-ELISA) in a population of 330 symptomatic grapevine leaf samples. CP products of eight isolates were cloned and nucleotide sequences were determined. Parsimonious trees indicated that GFLV isolates from Iran formed a distinct cluster, suggesting an independent evolution.

Based on the purpose of conservation planning for native species, sixteen populations of cattle, goat and sheep were analyzed by amplification of genomic DNA using inter-simple sequence repeat (ISSR) markers to estimate of genetic structure. DNA samples of 275 animals were collected to Paccess their genetic content. The polymorphism information content (PIC) values and genetic diversity in sheep populations were higher than the others. The mean coefficient of gene differentiation (Gst) was 0.3615, indicating that 19.42% of the genetic diversity resided within the population. In total, 60 fragments in PCR products were indicated by using ISSR primers and generally most of the fragments were common in all populations, but differed in their frequency. A cluster analysis was carried out using unweighed pair group method with arithmetic averages (UPGMA) and dendrogram illustrated genetic relationships among 275 individuals in three species. Haplotypes were constructed computationally and frequencies were compared in each species. The results of this study can provide basic molecular information for future research on native livestock using ISSR markers.

Ethylene plays an important role in wide-ranging aspects of plant growth and development, including fruit ripening, leaf and flower senescence. In this study, the expression patterns of two genes involved in the ethylene signal transduction pathway (RhCTR1 and RhCTR2) were investigated during the flower opening stages in two Rosa hybrida cultivars, ‘Black magic’ and ‘Maroussia’, which are characterized by short and long vase lives, respectively. RhCTR1 expression increased significantly during flower opening in both cultivars, but its expression level in cv. Maroussia was significantly higher than that in cv. Black magic. No variation in gene expression was detected for RhCTR2 in both cultivars. Therefore, this study showed that the vase life of the two cultivars correlated with the expression of RhCTR1, but not with that of RhCTR2, the behavior of which is typical of a constitutive gene.