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Leishmania infantum is responsible for human and canine leishmaniasis in the Mediterranean basin, where the major vector is Phlebotomus perniciosus. Because isolation of sufficient parasites from the sand fly gut is technically challenging, axenic cultivation of promastigotes is routinely used to obtain material for biochemical and genetic analyses. Here, we report the use of Spliced Leader RNA-seq (SL-seq) to compare transcript abundance in cultured promastigotes and those obtained from the whole midgut of the sand fly 5 days after infection. SL-seq allows for amplification of RNA from the parasite avoiding contamination with RNA from the gut of the insect. The study has been performed by means of a single technical replicate comparing pools of samples obtained from sand fly-derived (sfPro) and axenic culture promastigotes (acPro). Although there was a moderate correlation (R2 = 0.83) in gene expression, 793 genes showed significantly different (≥2-fold, p <0.05) mRNA levels in sand fly-derived promastigotes and in culture, of which 31 were up-regulated ≥8-fold (p < 10-8 in most cases). These included several genes that are typically up-regulated during metacyclogenesis, suggesting that sand fly-derived promastigotes contain a substantial number of metacyclics, and/or that their differentiation status as metacyclics is more advanced in these populations. Infection experiments and studies evaluating the proportion of metacyclic promastigotes in culture and within the sand fly gut, previously reported by us, support the last hypothesis.

Background Trypanosoma brucei is a unicellular parasite which multiplies in mammals (bloodstream form) and Tsetse flies (procyclic form). Trypanosome RNA polymerase II transcription is polycistronic, individual mRNAs being excised by trans splicing and polyadenylation. We previously made detailed measurements of mRNA half-lives in bloodstream and procyclic forms, and developed a mathematical model of gene expression for bloodstream forms. At the whole transcriptome level, many bloodstream-form mRNAs were less abundant than was predicted by the model. Results We refined the published mathematical model and extended it to the procyclic form. We used the model, together with known mRNA half-lives, to predict the abundances of individual mRNAs, assuming rapid, unregulated mRNA processing; then we compared the results with measured mRNA abundances. Remarkably, the abundances of most mRNAs in procyclic forms are predicted quite well by the model, being largely explained by variations in mRNA decay rates and length. In bloodstream forms substantially more mRNAs are less abundant than predicted. We list mRNAs that are likely to show particularly slow or inefficient processing, either in both forms or with developmental regulation. We also measured ribosome occupancies of all mRNAs in trypanosomes grown in the same conditions as were used to measure mRNA turnover. In procyclic forms there was a weak positive correlation between ribosome density and mRNA half-life, suggesting cross-talk between translation and mRNA decay; ribosome density was related to the proportion of the mRNA on polysomes, indicating control of translation initiation. Ribosomal protein mRNAs in procyclics appeared to be exceptionally rapidly processed but poorly translated. Conclusions Levels of mRNAs in procyclic form trypanosomes are determined mainly by length and mRNA decay, with some control of precursor processing. In bloodstream forms variations in nuclear events play a larger role in transcriptome

Background Trypanosoma brucei is a unicellular parasite which multiplies in mammals (bloodstream form) and Tsetse flies (procyclic form). Trypanosome RNA polymerase II transcription is polycistronic, individual mRNAs being excised by trans splicing and polyadenylation. We previously made detailed measurements of mRNA half-lives in bloodstream and procyclic forms, and developed a mathematical model of gene expression for bloodstream forms. At the whole transcriptome level, many bloodstream-form mRNAs were less abundant than was predicted by the model. Results We refined the published mathematical model and extended it to the procyclic form. We used the model, together with known mRNA half-lives, to predict the abundances of individual mRNAs, assuming rapid, unregulated mRNA processing; then we compared the results with measured mRNA abundances. Remarkably, the abundances of most mRNAs in procyclic forms are predicted quite well by the model, being largely explained by variations in mRNA decay rates and length. In bloodstream forms substantially more mRNAs are less abundant than predicted. We list mRNAs that are likely to show particularly slow or inefficient processing, either in both forms or with developmental regulation. We also measured ribosome occupancies of all mRNAs in trypanosomes grown in the same conditions as were used to measure mRNA turnover. In procyclic forms there was a weak positive correlation between ribosome density and mRNA half-life, suggesting cross-talk between translation and mRNA decay; ribosome density was related to the proportion of the mRNA on polysomes, indicating control of translation initiation. Ribosomal protein mRNAs in procyclics appeared to be exceptionally rapidly processed but poorly translated. Conclusions Levels of mRNAs in procyclic form trypanosomes are determined mainly by length and mRNA decay, with some control of precursor processing. In bloodstream forms variations in nuclear events play a larger role in transcriptome

A series of machining experiments on the Oil Palm Empty-Fruit Bunch (OPEFB) particle board were carried out using tungsten carbide tools, to ascertain the predominant mechanism of tool wear when machining this material. The experiments were carried out using a high speed lathe, which machined a rotating disc of the OPEFB particle board. It was found that mechanical abrasion and micro-fracture was the primary mode of tool failure when machining OPEFB particle board. The low cutting temperature recorded during the machining experiments provides compelling evidence to eliminate any significant effect of electrochemical and oxidation mechanisms on the wear of tungsten carbide tools. Therefore, the wear of cemented tungsten carbide tools when machining OPEFB particle board was predominantly by mechanical wear mechanisms. The results of this study implies that the high tool wear experienced during the machining of OPEFB particle board, may limit its use in the manufacture of value-added products, unless the boards are priced competitively in the market.

A series of machining experiments on the Oil Palm Empty-Fruit Bunch (OPEFB) particle board were carried out using tungsten carbide tools, to ascertain the predominant mechanism of tool wear when machining this material. The experiments were carried out using a high speed lathe, which machined a rotating disc of the OPEFB particle board. It was found that mechanical abrasion and micro-fracture was the primary mode of tool failure when machining OPEFB particle board. The low cutting temperature recorded during the machining experiments provides compelling evidence to eliminate any significant effect of electrochemical and oxidation mechanisms on the wear of tungsten carbide tools. Therefore, the wear of cemented tungsten carbide tools when machining OPEFB particle board was predominantly by mechanical wear mechanisms. The results of this study implies that the high tool wear experienced during the machining of OPEFB particle board, may limit its use in the manufacture of value-added products, unless the boards are priced competitively in the market.

Because of severe restrictions placed by the National Authority, no authentic data on subsoil details below Taj Mahal - a protected monument - is available. For the first time, an attempt has been made to fill in gaps that exist in our knowledge of subsoil profile below the structure and present a plausible appraisal of foundation performance during the existence of the structure. Since details of foundations cited in literature on Taj Mahal really fall into the realms of architectural conjecture, in the present analysis, engineering intuition and judgement have gone into making certain premises regarding the probable type, dimensions and the depth of the existing foundations of Taj Mahal. These premises, complimented by borehole data and laboratory tests have enabled the assessment of the foundation performance to be made in as realistic a manner as is practically possible.

Foundations of 8 Steel Oil storage tanks and two fire water tanks were proportioned limiting total settlement to 100 mm. The soil at the site consists of alternating layers of cohesive and cohesionless soils. Settlement estimates were based on currently available methods with suitable modifications to the situation met with. The tanks were load tested (Hydrotest) and settlements observed at nine locations along the periphery on tank shell base. These observed settlements are compared with the estimated values.

A Lecture cum-cinema hall was constructed on a terrace developed at the top of a hillock at a site located in the north-eastern part of India. At the time of development of the site, excavated soil was dumped on the slopes and retaining walls were constructed to retain the earth. After the first monsoon, the retaining walls gave way. Further distress in the vicinity of the building was noticed in the subsequent three years. The paper describes the details of the above failure, the investigations carried out and the remedial measures suggested.

Oil and Natural Gas Commission of India plans to construct a multi-storeyed building in Dehradun city at the foothills of Himalayas. The geotechnical investigations were carried out at site to determine soil parameters for foundation design. It was found that it was not possible to provide a raft foundation for the building and hence alternatively the pile foundation was suggested. The pile load capacity was predicted on the basis of soil parameters determined and a comparison was then made with the results obtained by carrying out load tests on constructed piles.