Molecular Basis of Aluminium Toxicity in Plants: A Review

Aluminium toxicity in acid soils having pH below 5.5, affects the production of staple food crops, vegetables and cash crops worldwide. About 50% of the world’s potentially arable lands are acidic. It is trivalent cationic form i.e. Al3+ that limits the plant’s growth. Absorbed Aluminium inhibits root elongation and adversely affects plant growth. Recently researches have been conducted to understand the mechanism of Aluminium toxicity and resistance which is important for stable food production in future. Aluminium resistance depends on the ability of the plant to tolerate Aluminium in symplast or to exclude it to soil. Physiological and molecular basis of Aluminium toxicity and resistance mechanism are important to understand for developing genetically engineered plants for Al toxicity resistance. This paper provides an overview of the state of art in this field.

Intraoperative magnetic resonance imaging in neurosurgery and anesthetic considerations

Currently, magnetic resonance imaging(MRI) is the only imaging modality available which is capable of acquiring intra-operative images frequently with acceptable spatial and contrast resolution. However, the incorporation of MRI technology into the operating room requires special anesthetic considerations. It may include various aspects such as transport, remote location anesthesia, strong electromagnetic field, use of approved items, equipment counts, possible emergencies, and surgery in awake patients. The patient safety may be compromised by health-related, equipment-related, and procedure-related risks. Direct patient observation may be compromised by acoustic noise, darkened environment, obstructed line of sight, and distractions along with difficult access to the patient for airway management. Most often, the patient's head will be 180° away from the anesthesiologist during the procedure. Several monitors exist that are designed for conditional use in a MR environment. The general design criterion in these monitors is to eliminate conductors that carry electrical signals for monitoring physiologic parameters of the patient. General anesthesia requires an extended anesthetic circuit for ventilation maintenance and drug administration because the patient is located farther from the anesthesia machine than in traditional operating room settings. Dead space creates a time delay before the volatile anesthetic and drugs are administered and when expected effects can be observed. Therefore, the attending anaesthesiologists must understand the above aspects for safe conduct of neurosurgical procedures by minimizing MRI associated accidents while assuring optimal patient vigilance.

The Molecular and Structural Basis of HBV-resistance to Nucleos(t)ide Analogs

Infection with hepatitis B virus(HBV)is a worldwide health problem.Chronic hepatitis B can lead to fibrosis,liver cirrhosis,and hepatocellular carcinoma(HCC).Management of the latter two conditions often requires liver transplantation.Treatment with conventional interferon or pegylated interferon alpha can clear the virus,but the rates are very low.The likelihood,however,of viral resistance to interferon is minimal.The main problems with this therapy are the frequency and severity of side effects.In contrast,nucleos(t)ide analogs(NAs)have significantly lower side effects,but require long term treatment as sustained virological response rates are extremely low.However,long term treatment with NAs increases the risk for the development of anti-viral drug resistance.Only by understanding the molecular basis of resistance and using agents with multiple sites of action can drugs be designed to optimally prevent the occurrence of HBV antiviral resistance.

Secondary Structural Elements of the HCV X-region Involved in Viral Replication

Background and Aims:The noncoding regions in the 3'-untranslated region (UTR) of the hepatitis C virus (HCV)genome contain secondary structures that are important for replication.The aim of this study was to identify detailed conformational elements of the X-region involved in HCV replication.Methods:Ribonucleic acid (RNA) structural analogs X94,X12,and X12c were constructed to have identical conformation but 94%,12%,and 0% sequence identity,respectively,to the X region of HCV genotype 2a.Effects of structural analogs on replication of HCV genotypes 1b and 2a HCV RNA were studied by quantitative reverse transcriptase polymerase chain reaction.Results:In replicon BB7 cells,a constitutive replication model,HCV RNA levels decreased to 55%,52%,53%,and 54% after transfection with expression plasmids generating RNA structural analogs 5B-46,X-94,X-12,and X-12c,respectively (p<0.001 for all).In an HCV genotype 2a infection model,RNA analogs 5B-46,X-94,and X-12 in hepatic cells inhibited replication to 11%,9%,and 12%,respectively.Because the X-12 analog was only 12% identical to the corresponding sequence of HCV genotype 2a,the sequence per se,or antisense effects were unlikely to be involved.Conclusions:The data suggest that conformation of secondary structures in 3'-UTR of HCV RNA genome is required for HCV replication.Stable expression of RNA analogs predicted to have identical stem-loop structures might inhibit HCV infection of hepatocytes in liver and may represent a novel approach to design anti-HCV agents.