Antimicrobial susceptibility profiles associated with bacterial meningitis among children: a referral hospital-based study in Iran

Bacterial meningitis continues to be associated with high morbidity and mortality rate worldwide, especially in the pediatric age group. This study was performed to identify the microbial etiologies of meningitis among 31 children, who were admitted in the Emergency Ward of a referral pediatric hospital in Iran. Culture identification showed that Streptococcus pneumoniae (12 subjects), Haemophilus influenzae (11 subjects) were the most common bacteria, followed by Escherichia coli (7 cases) and Neisseria meningitidis (only one case). Antibiotic susceptibility tests revealed that vancomycin had the best effect on S. pneumoniae in comparison with other antibiotics, whereas H. influenzae and E. coli were more susceptible to ceftriaxone, ceftazidime, and ceftizoxime than other antibiotics. In conclusion, despite the advances in antibiotic therapy and vaccine development, bacterial meningitis still is a health problem. S. pneumoniae, H. influenzae, and N. meningitidis are the main sources of bacterial meningitis, but other organisms such as E. coli should also be suspected, when a case is admitted to a referral pediatric hospital.     

Deciphering interactions used by the influenza virus NS1 protein to silence the host antiviral sensor protein RIG-I using a bacterial reverse two-hybrid system

The majority of biological processes are controlled and regulated by an intricate network of thousands of interacting proteins. Identifying and understanding the key components of these protein networks, especially those that play a critical role in disease, is a challenge that promises to dramatically alter our current approach to healthcare. To facilitate this process, we have developed a method for the rapid construction of a chromosomally integrated, bacterial reverse two-hybrid system (RTHS) that enables the identification of interacting protein partners. Chromosomal integration of the RTHS enables stable protein expression, free of plasmid copy-number effects, as well as eliminating false positives arising from plasmid ejection. We have utilized this approach to identify the interactions used by the influenza virus NS1 protein to silence the host's antiviral defences.     

Development of Human Recombinant Antibodies Against ROR1 Tumor Antigen

Background:Receptor tyrosine kinase-like orphan receptor 1 (ROR1) is an oncofetal antigen expressed on many types of cancer cells, but not normal adult cells. ROR1 antigen contributes to cancer development and progression by several signaling pathways. ROR1 expression has been associated with tumor growth, survival, and metastasis. In this study specific human recombinant antibodies were selected against ROR1 antigen for their use in cancer immunotherapy.Methods:Phage display technology was used to produce phage antibody from a human scFv library. Phage concentration was determined to confirm the phage rescue process. Panning procedure was performed to isolate specific scFv clones against ROR1 epitope. Phage ELISA was done to evaluate the reactivity of the selected scFvs.Results:Two specific human scFvs with frequencies of 20% and 25% were selected against ROR1 peptide. The antibodies showed specific reaction to the corresponding epitopes in phage ELISA.DiscussionCancer targeted therapy using human specific antibodies is a new strategy, which is used in cancer therapy. The selected specific scFvs that target ROR1 epitope are human antibodies that originated from a human library and have the potential to be used in clinic in cancer immunotherapy of ROR1 positive tumors without induction of human anti mouse antibody (HAMA) response.Key Words: ROR1, Phage display, scFV library, Cancer     

Metabolic control of cytosolic‐facing pools of diacylglycerol in budding yeast

Diacylglycerol (DAG) is a key signaling lipid and intermediate in lipid metabolism. Our knowledge of DAG distribution and dynamics in cell membranes is limited. Using live‐cell fluorescence microscopy we investigated the localization of yeast cytosolic‐facing pools of DAG in response to conditions where lipid homeostasis and DAG levels were known to be altered. Two main pools were monitored over time using DAG sensors. One pool was associated with vacuolar membranes and the other localized to sites of polarized growth. Dynamic changes in DAG distribution were observed during resumption of growth from stationary phase, when DAG is used to support phospholipid synthesis for membrane proliferation. Vacuolar membranes experienced constant morphological changes displaying DAG enriched microdomains coexisting with liquid‐disordered areas demarcated by Vph1. Formation of these domains was dependent on triacylglycerol (TAG) lipolysis. DAG domains and puncta were closely connected to lipid droplets. Lack of conversion of DAG to phosphatidate in growth conditions dependent on TAG mobilization, led to the accumulation of DAG in a vacuolar‐associated compartment, impacting the polarized distribution of DAG at budding sites. DAG polarization was also regulated by phosphatidylserine synthesis/traffic and sphingolipid synthesis in the Golgi.      

Human Gyrovirus Apoptin shows a similar subcellular distribution pattern and apoptosis induction as the chicken anaemia virus derived VP3/Apoptin

The chicken anaemia virus-derived protein Apoptin/VP3 (CAV-Apoptin) has the important ability to induce tumour-selective apoptosis in a variety of human cancer cells. Recently the first human Gyrovirus (HGyV) was isolated from a human skin swab. It shows significant structural and organisational resemblance to CAV and encodes a homologue of CAV-Apoptin/VP3. Using overlapping primers we constructed a synthetic human Gyrovirus Apoptin (HGyV-Apoptin) fused to green fluorescent protein in order to compare its apoptotic function in various human cancer cell lines to CAV-Apoptin. HGyV-Apoptin displayed a similar subcellular expression pattern as observed for CAV-Apoptin, marked by translocation to the nucleus of cancer cells, although it is predominantly located in the cytosol of normal human cells. Furthermore, expression of either HGyV-Apoptin or CAV-Apoptin in several cancer cell lines triggered apoptosis at comparable levels. These findings indicate a potential anti-cancer role for HGyV-Apoptin.     

Ancient whole genome duplications, novelty and diversification: the WGD Radiation Lag-Time Model

Many large and economically important plant groups (e.g. Brassicaceae, Poaceae, Asteraceae, Fabaceae and Solanaceae) have had ancient whole genome duplications (WGDs) occurring near or at the time of their origins, suggesting that WGD contributed to the origin of novel key traits and drove species diversification. However, these large clades show phylogenetic asymmetries with a species-rich crown group and a species-poor sister clade, suggesting significant 'lag-times' between WGDs and radiations. The species-poor sister groups share many key traits, but are often restricted to the hypothesized center of origin for the larger clade. Thus, the ultimate success of the crown group does not only involve the WGD and novel key traits, but largely subsequent evolutionary phenomena including later migration events, changing environmental conditions and/or differential extinction rates.     

3‐Aryl Coumarin Derivatives Bearing Aminoalkoxy Moiety as Multi‐Target‐Directed Ligands against Alzheimer's Disease

Two series of novel coumarin derivatives, substituted at 3 and 7 positions with aminoalkoxy groups, are synthesized, characterized, and screened. The effect of amine substituents and the length of cross‐linker are investigated in acetyl‐ and butyrylcholinesterase (AChE and BuChE) inhibition. Target compounds show moderate to potent inhibitory activities against AChE and BuChE. 3‐(3,4‐Dichlorophenyl)‐7‐[4‐(diethylamino)butoxy]‐2H‐chromen‐2‐one ( 4y ) is identified as the most potent compound against AChE (IC₅₀=0.27 μm ). Kinetic and molecular modeling studies affirmed that compound 4y works in a mixed‐type way and interacts simultaneously with the catalytic active site (CAS) and peripheral anionic site (PAS) of AChE. In addition, compound 4y blocks β‐amyloid (Aβ) self‐aggregation with a ratio of 44.11 % at 100 μm and significantly protects PC12 cells from H₂O₂‐damage in a dose‐dependent manner.