Quantum channel based on correlated twin laser beams

This work is the development and analysis of the recently proposed quantum cryptographic protocol, based on the use of the two-mode coherently correlated states. The protocol is supplied with the cyrptographic control procedures. The channel error properties and stability against eavesdropping are examined. State detection features are proposed.Comment: The Seventh International Conference on Quantum Communication, Measurement and Computing,Glasgow 200

Natural selection and genetic variation in a promising Chagas disease drug target: Trypanosoma cruzi trans-sialidase

Rational drug design is a powerful method in which new and innovative therapeutics can be designed based on knowledge of the biological target aiming to provide more efficacious and responsible therapeutics. Understanding aspects of the targeted biological agent is important to optimize drug design and preemptively design to slow or avoid drug resistance. Chagas disease, an endemic disease for South and Central America and Mexico is caused by Trypanosoma cruzi, a protozoan parasite known to consist of six separate genetic clusters or DTUs (discrete typing units). Chagas disease therapeutics are problematic and a call for new therapeutics is widespread. Many researchers are working to use rational drug design for developing Chagas drugs and one potential target that receives a lot of attention is the T. cruzi trans-sialidase protein. Trans-sialidase is a nuclear gene that has been shown to be associated with virulence. In T. cruzi, trans-sialidase (TcTS) codes for a protein that catalyzes the transfer of sialic acid from a mammalian host coating the parasitic surface membrane to avoid immuno-detection. Variance in disease pathology depends somewhat on T. cruzi DTU, as well, there is considerable genetic variation within DTUs. However, the role of TcTS in pathology variance among and within DTU’s is not well understood despite numerous studies of TcTS. These previous studies include determining the crystalline structure of TcTS as well as the TS protein structure in other trypanosomes where the enzyme is often inactive. However, no study has examined the role of natural selection in genetic variation in TcTS. In order to understand the role of natural selection in TcTS DNA sequence and protein variation, we sequenced 540 bp of the TcTS gene from 48 insect vectors. Because all 48 sequences had multiple polymorphic bases, we examined cloned sequences from two of the insect vectors. The data are analyzed to understand the role of natural selection in shaping genetic variation in TcTS and interpreted in light of the possible role of TcTS as a drug target

Construction and utilisation of a bidirectional reporter vector in the analysis of two nod-boxes in of Rhizobium loti : a thesis presented in partial fulfilment of the requirements for the Degree of Master of Science in Molecular Genetics at Massey University

The nod-box is a 47bp cis-acting regulatory region which has been conserved amongst every species of Rhizobium studied to date. In species such as R. meliloti and R. leguminosarum, the nod-box has been shown to promote constitutive activity towards the regulatory nodD gene, and flavonoid-inducible expression towards the divergently-transcribed nodABCIJ operon. This bidirectional regulation of the so-called common nod genes was not observed in R. loti. A previous analysis of this species had shown that its nod-box promoted inducible activity towards the truncated 'nodD' gene, as well as the nodACIJ operon. It was the unusual arrangement of these R. loti nod genes that had initially aroused interest in this bacteria. To further investigate the role of the nod-box in the regulation of the R. loti common nod genes, a bidirectional reporter vector (pSPV4) was constructed. This novel vector allowed the promoter activity of a cloned nod-box-containing fragment to be concurrently measured in either direction using the same culture of cells. To achieve this construct, the gusA gene from pRAJ260 was blunt-end ligated into pUC21. An in-frame ribosome binding site (rbs) was cloned upstream of the gusA coding sequence to facilitate transcriptional fusions. The rbs and gusA gene were later excised as a functional unit and blunt-end ligated into pMP220 alongside the B-galactosidase reporter gene but in the opposite orientation. Hence, both reporter genes could be divergently transcribed from a common regulatory region cloned into the multiple cloning site that separated the genes. The fragments of DNA that were eventually cloned into the bidirectional vector were generated through the polymerase chain reaction. Each DNA insert contained the nod-box bracketed by differing lengths of flanking region. Once these PCR-generated fragments had been sequenced in pUC118 and subcloned into pSPV4, the resulting constructs were transformed into R. loti cells by electroporation. As the electroporation of these cells had not previously been reported, the conditions for this procedure were established and optimised. The results obtained from the bidirectional reporter assays disagreed with those observed in the earlier assays by Teo (1990). Neither the nodACIJ nod-box of NZP2037 nor the nodB nod-box of NZP2213, showed bidirectional inducible expression. In fact, both nod-boxes showed constitutive expression in the 'nodD' direction and inducible expression in the opposite direction. This indicates that the control of the nod genes in R. loti is fundamentally the same as that seen in other fast-growing Rhizobium species. Three regulatory elements affecting the levels of nod gene expression have tentatively been identified outside the nod-box sequence, though the results indicating their presence may simply be·due to spacing differences between the nod-box and the reporter gene

Tissue-specific expression of calcium channels

The high-voltage-activated calcium channel is a multimeric protein complex containing 1, 2/δ, β, and γ subunits. The 1 subunit is the ion conduction channel and contains the binding sites for calcium channel blockers and toxins. Three genes code for distinct L-type, dihydropyridine-sensitive 1 subunits; one gene codes for the neuronal P-type (Purkinje) 1 subunit; and one gene codes for the neuronal N-type 1 subunit. The smooth and cardiac muscle L-type calcium channel 1 subunits are splice variants of the same gene. The 1 subunits are coexpressed with a common 2/δ subunit and tissue-specific β subunits (at least three genes). The γ subunit apparently is expressed only in skeletal muscle. The properties of these cloned and expressed calcium channels are discussed here

BCKDH: the missing link in apicomplexan mitochondrial metabolism is required for full virulence of Toxoplasma gondii and Plasmodium berghei

While the apicomplexan parasites Plasmodium falciparum and Toxoplasma gondii are thought to primarily depend on glycolysis for ATP synthesis, recent studies have shown that they can fully catabolize glucose in a canonical TCA cycle. However, these parasites lack a mitochondrial isoform of pyruvate dehydrogenase and the identity of the enzyme that catalyses the conversion of pyruvate to acetyl-CoA remains enigmatic. Here we demonstrate that the mitochondrial branched chain ketoacid dehydrogenase (BCKDH) complex is the missing link, functionally replacing mitochondrial PDH in both T. gondii and P. berghei. Deletion of the E1a subunit of T. gondii and P. berghei BCKDH significantly impacted on intracellular growth and virulence of both parasites. Interestingly, disruption of the P. berghei E1a restricted parasite development to reticulocytes only and completely prevented maturation of oocysts during mosquito transmission. Overall this study highlights the importance of the molecular adaptation of BCKDH in this important class of pathogens