Insights to bioprocess and treatment competence of urban wetlands.

Wetlands play a major role in the recharge of groundwater resources, maintenance of water quality (remediation), moderate microclimate while supporting local livelihood through provision of fish, fodder, etc. The present study aims to investigate algal-bacterial consortium as a function of residence time with the water quality dynamics in two major wetlands in Bangalore city, India. Over thirty-two genera of algae were recorded with more than 40 species in the lakes and two dominant bacterial assemblages. The higher Ammonium-N content favoured the growth of these members. Significant correlation was observed between the nutrient concentrations and the community structure at the inflows and the outflows. The algal community showed negative correlation to filterable COD and high nutrients levels while bacterial abundance was observed under high loadings. The green algae Chlorophyceae (Chlorella blooms), which are indicators of nutrient enrichment were observed predominantly, that needs an immediate attention. Higher overall treatment efficiency was observed in terms of CNP removal during the Pre-monsoon season attributed to absence of macrophytes cover and rapid growth of algal assemblage's due to higher temperature regimes with adequate solar insolation.

Positron Emission Tomography and Magnetic Resonance Imaging of Cellular Inflammation in Patients with Abdominal Aortic Aneurysms.

OBJECTIVES: Inflammation is critical in the pathogenesis of abdominal aortic aneurysm (AAA) disease. Combined (18)F-fludeoxyglucose ((18)F-FDG) positron emission tomography with computed tomography (PET-CT) and ultrasmall superparamagnetic particles of iron oxide (USPIO)-enhanced magnetic resonance imaging (MRI) are non-invasive methods of assessing tissue inflammation. The aim of this study was to compare these techniques in patients with AAA. MATERIALS AND METHODS: Fifteen patients with asymptomatic AAA with diameter 46 ± 7 mm underwent PET-CT with (18)F-FDG, and T2*-weighted MRI before and 24 hours after administration of USPIO. The PET-CT and MRI data were then co-registered. Standardised uptake values (SUVs) were calculated to measure (18)F-FDG activity, and USPIO uptake was determined using the change in R2*. Comparisons between the techniques were made using a quadrant analysis and a voxel-by-voxel evaluation. RESULTS: When all areas of the aneurysm were evaluated, there was a modest correlation between the SUV on PET-CT and the change in R2* on USPIO-enhanced MRI (n = 70,345 voxels; r = .30; p < .0001). Although regions of increased (18)F-FDG and USPIO uptake co-localised on occasion, this was infrequent (kappa statistic 0.074; 95% CI 0.026-0.122). (18)F-FDG activity was commonly focused in the shoulder region whereas USPIO uptake was more apparent in the main body of the aneurysm. Maximum SUV was lower in patients with mural USPIO uptake. CONCLUSIONS: Both (18)F-FDG PET-CT and USPIO-MRI uptake identify vascular inflammation associated with AAA. Although they demonstrate a modest correlation, there are distinct differences in the pattern and distribution of uptake, suggesting a differential detection of macrophage glycolytic and phagocytic activity respectively.

Aortic stenosis, atherosclerosis, and skeletal bone: is there a common link with calcification and inflammation?

AIMS: The pathophysiology of aortic stenosis shares many similarities with atherosclerosis and skeletal bone formation. Using non-invasive imaging, we compared aortic valve calcification and inflammation activity with that measured in atherosclerosis and bone. METHODS AND RESULTS: Positron emission and computed tomography was performed using 18F-sodium fluoride (18F-NaF, calcification) and 18F-fluorodeoxyglucose (18F-FDG, inflammation) in 101 patients with calcific aortic valve disease (81 aortic stenosis and 20 aortic sclerosis). Calcium scores and positron emission tomography tracer activity (tissue-to-background ratio; TBR) were measured in the aortic valve, coronary arteries, thoracic aorta, and bone. Over 90% of the cohort had coexistent calcific atheroma, yet correlations between calcium scores were weak or absent (valve vs. aorta r(2) = 0.015, P = 0.222; valve vs. coronaries r(2) = 0.039, P = 0.049) as were associations between calcium scores and bone mineral density (BMD vs. valve r(2) = 0.000, P = 0.766; vs. aorta r(2) = 0.052, P = 0.025; vs. coronaries r(2) = 0.016, P = 0.210). 18F-NaF activity in the valve was 28% higher than in the aorta (TBR: 2.66 ± 0.84 vs. 2.11 ± 0.31, respectively, P < 0.001) and correlated more strongly with the severity of aortic stenosis (r(2) = 0.419, P < 0.001) than 18F-NaF activity outwith the valve (valve vs. aorta r(2) = 0.167, P < 0.001; valve vs. coronary arteries r(2) = 0.174, P < 0.001; valve vs. bone r(2) = 0.001, P = 0.806). In contrast, 18F-FDG activity was lower in the aortic valve than the aortic atheroma (TBR: 1.56 ± 0.21 vs. 1.81 ± 0.24, respectively, P < 0.001) and more closely associated with uptake outwith the valve (valve vs. aorta r(2) = 0.327, P < 0.001). CONCLUSION: In patients with aortic stenosis, disease activity appears to be determined by local calcific processes within the valve that are distinct from atherosclerosis and skeletal bone metabolism.

Engineered dimer interface mutants of triosephosphate isomerase: the role of inter-subunit interactions in enzyme function and stability.

The role of inter-subunit interactions in maintaining optimal catalytic activity in triosephosphate isomerase (TIM) has been probed, using the Plasmodium falciparum enzyme as a model. Examination of subunit interface contacts in the crystal structures suggests that residue 75 (Thr, conserved) and residue 13 (Cys, variable) make the largest number of inter-subunit contacts. The mutants Cys13Asp (C13D) and Cys13Glu (C13E) have been constructed and display significant reduction in catalytic activity when compared with wild-type (WT) enzyme (∼ 7.4-fold decrease in k(cat) for the C13D and ∼ 3.3-fold for the C13E mutants). Analytical gel filtration demonstrates that the C13D mutant dissociates at concentrations <1.25 µM, whereas the WT and the C13E enzymes retain the dimeric structure. The order of stability of the mutants in the presence of chemical denaturants, like urea and guanidium chloride, is WT > Cys13Glu > Cys13Asp. Irreversible thermal precipitation temperatures follow the same order as well. Modeling studies establish that the Cys13Asp mutation is likely to cause a significantly greater structural perturbation than Cys13Glu. Analysis of sequence and structural data for TIMs from diverse sources suggests that residues 13 and 82 form a pair of proximal sites, in which a limited number of residue pairs may be accommodated.

Identification of putative regulatory motifs in the upstream regions of co-expressed functional groups of genes in Plasmodium falciparum.

BACKGROUND: Regulation of gene expression in Plasmodium falciparum (Pf) remains poorly understood. While over half the genes are estimated to be regulated at the transcriptional level, few regulatory motifs and transcription regulators have been found. RESULTS: The study seeks to identify putative regulatory motifs in the upstream regions of 13 functional groups of genes expressed in the intraerythrocytic developmental cycle of Pf. Three motif-discovery programs were used for the purpose, and motifs were searched for only on the gene coding strand. Four motifs -- the 'G-rich', the 'C-rich', the 'TGTG' and the 'CACA' motifs -- were identified, and zero to all four of these occur in the 13 sets of upstream regions. The 'CACA motif' was absent in functional groups expressed during the ring to early trophozoite transition. For functional groups expressed in each transition, the motifs tended to be similar. Upstream motifs in some functional groups showed 'positional conservation' by occurring at similar positions relative to the translational start site (TLS); this increases their significance as regulatory motifs. In the ribonucleotide synthesis, mitochondrial, proteasome and organellar translation machinery genes, G-rich, C-rich, CACA and TGTG motifs, respectively, occur with striking positional conservation. In the organellar translation machinery group, G-rich motifs occur close to the TLS. The same motifs were sometimes identified for multiple functional groups; differences in location and abundance of the motifs appear to ensure different modes of action. CONCLUSION: The identification of positionally conserved over-represented upstream motifs throws light on putative regulatory elements for transcription in Pf.

Conformational and sequence signatures in beta helix proteins.

beta helix proteins are characterized by a repetitive fold, in which the repeating unit is a beta-helical coil formed by three strand segments linked by three loop segments. Using a data set of left- and right-handed beta helix proteins, we have examined conformational features at equivalent positions in successive coils. This has provided insights into the conformational rules that the proteins employ to fold into beta helices. Left-handed beta helices attain their equilateral prism fold by incorporating "corners" with the conformational sequence P(II)-P(II)-alpha(L)-P(II), which imposes sequence restrictions, resulting in the first and third P(II) residues often being G and a small, uncharged residue (V, A, S, T, C), respectively. Right-handed beta helices feature mid-sized loops (4, 5, or 6 residues) of conserved conformation, but not of conserved sequence; they also display an alpha-helical residue at the C-terminal end of L2 loops. Backbone conformational parameters (phi,psi) that permit the formation of continuous, loopless beta helices (Perutz nanotubes) have also been investigated.

Patterns of tree growth in relation to environmental variability in the tropical dry deciduous forest at Mudumalai, southern India.

Tree diameter growth is sensitive to environmental fluctuations and tropical dry forests experience high seasonal and inter-annual environmental variation. Tree growth rates in a large permanent plot at Mudumalai, southern India, were examined for the influences of rainfall and three intrinsic factors (size, species and growth form) during three 4-year intervals over the period 1988-2000. Most trees had lowest growth during the second interval when rainfall was lowest, and skewness and kurtosis of growth distributions were reduced during this interval. Tree diameter generally explained less than 10% of growth variation and had less influence on growth than species identity or time interval. Intraspecific variation was high, yet species identity accounted for up to 16% of growth variation in the community. There were no consistent differences between canopy and understory tree growth rates; however, a few subgroups of species may potentially represent canopy and understory growth guilds. Environmentally-induced temporal variations in growth generally did not reduce the odds of subsequent survival. Growth rates appear to be strongly influenced by species identity and environmental variability in the Mudumalai dry forest. Understanding and predicting vegetation dynamics in the dry tropics thus also requires information on temporal variability in local climate.

Use of atomic force microscopy to reveal sperm ultrastructure in HIV-patients on highly active antiretroviral therapy.

Atomic force microscopy (AFM) has been employed to examine morphological and topographical changes caused by human immunodeficiency virus (HIV) and the effects of highly active antiretroviral therapy (HAART) on spermatozoon of HIV infected patients. This powerful technique has allowed us to visualize morphological alterations present in the spermatozoa of patients either with or without treatment. In addition to this, even the minute details, such as viral particles, located on the membrane of the spermatozoa, and the merging of such particles on the surface of the spermatozoa were detected with precision. The most important aspect is that AFM, unlike electron microscopy, permits to image virions in their nearly natural environment. Excess of damage of spermatozoon is due to the chemicals involved in HAART rather than the damage made by virus.

Morphological investigation of Toxoplasma gondii in vivo by a multiple beam interference microscope.

A recently developed technique, namely multiple beam interference microscopy, has been applied to investigate the morphology of the parasite Toxoplasma gondii for the first time. The interference pattern obtained from the multiple internal reflection of a T. gondii, sandwiched between a glass plate and a cover plate, was focused on the objective of a conventional microscope. Because of the enhance contrast, several details of sub cellular structure and separating compartments are clearly visible. Details reveal the presence of a nucleus, lipid body, dense granule, rhoptry and amylopectin. The wall thickness of the membrane of the lipid body and the amylopectin is of the order of 0.02 microm and can be clearly distinguished with the help of the present technique. The same parasite has also been examined with the help of atomic force microscopy, and because of its thick membrane, the inner structural details were not observed at all. Sub cellular details of T. gondii observed with the present technique have been reported earlier only by low amplification transmission electron microscopy and not by any optical microscopic technique.

Ultrastructural pathology of varicocele spermatozoa by using atomic force microscopy (AFM).

Ultrastructural investigation of pathological spermatozoa of patients having varicocele (grades I and III) in its natural environment (without fixation, dehydration, embedding, sectioning, etc.) was carried out by using Atomic Force Microscope (AFM) in tapping mode. This is a unique technique to examine the topographical structure with precision and to obtain 3-D images. It revealed structural alterations caused by the presence of varicocele. Not only neckpieces and flagella were defective, but also the head; particularly, dimensions and heights are altered.

Effect of an electric field on the motility of Entamoeba histolytica examined by multiple-beam interference microscopy.

A recently developed multiple-beam interference microscopic technique has been used to visualize submicroscopic structures of Entamoeba histolytica and their movements in applied external electric fields. The movements were videorecorded and it was found that at low current (120 microA) pseudopods are filled with hyaline ectoplasm. At slightly higher current (about 150 microA), the amoeba stops extending the pseudopods and loosens its attachment to the surface. At higher currents (200 microA), it forms a cyst and remains immobile for a time. Before this stage is reached a narrow ring is formed around the nucleus due to alterations in the proteins to protect it.

Ultrastructural investigation of human sperm using atomic force microscopy.

Ultrastructural investigation of human sperm in its natural environment (without fixation, dehydration, embedding, sectioning, etc.) was carried out by using atomic force microscope (AFM) in its tapping mode. This technique permits the examination of fine structural details of undamaged sperm and its topography with precision. Moreover, it allows 3D reconstruction of images and enhances the contrast to resolve details such as mitochondria that surround the axoneme at the sperm middle piece. An organized structure has been found in the flageller axoneme region. Ultrastructure also reveals folding and details of the depression of the membrane that cannot be examined with conventional techniques.

Correlates of the desired family size among Indian communities.

The People of India database of the Anthropological Survey of India documents 631 cultural, ecological, and economic traits of the 4635 communities to which the entire Indian population is assigned. Focusing on 1342 communities of South India, we looked for correlates of low (1 or 2 children) and high (4 or more children) desired family size (DFS) reported as the norm for any given community by key informants. We found 10 cultural and 18 economic traits to be significantly correlated to high DFS and 21 cultural and 9 economic traits to low DFS. The economic traits so identified are compatible with high family size being desired by parents who have little capability of investing in quality of offspring, but whose children contribute economically from an early age. In contrast, communities desiring low family size are part of the modern intensive agriculture/organized industry/services sector and invest heavily in educating their children. A composite index based on 27 economic traits (CEI) has a high predictive value with respect to the DFS for the entire set of 4635 Indian communities. The 31 cultural traits highly correlated to high or low DFS constitute 5 clusters that can be identified as characterizing scheduled tribes, scheduled castes, rural and landless lower castes, urban upper castes, and Moslems. Whereas economic traits have similar influence on DFS within each of these ethnic categories, Moslems demonstrate a significantly higher DFS for lower values of CEI.

On the relationship between bird and woody plant species diversity in the Uttara Kannada district of south India.

Bird species richness is inversely related to woody plant species diversity and vertical stratification in the natural vegetation of Uttara Kannada, the district with the largest contiguous tract of humid tropical forest in peninsular India. This inverse relationship may be explained by the fact that although the peninsular Indian evergreen forests are rich in woody plant species when compared with the drier vegetation, they harbor an impoverished bird fauna due to their smaller overall extent and greater isolation. Much of this impoverishment is accounted for by the absence of many species of understory timaliids characteristic of the humid evergreen forests of the Eastern Himalayas and Southeast Asia. The plantations of Uttara Kannada largely derive their bird fauna from the drier vegetation and exhibit the commoner trend of a positive correlation between bird species richness and vertical stratification of the vegetation.

Photoconductivity study of ZnSiP(2) and CdSe:Cu by a computer-controlled spectrometer.

Instead of scanning the photoconductivity spectra continuously, a special computer-controlled experimental setup has been designed that enables step by step scanning and allows the photoresponse to be measured for a desired amount of time at each wavelength. With the help of this technique, it is possible to detect the contribution from the slow component of photoconductivity. This helps to resolve the finer details of the spectrum. Photoconductivity spectra of ternary compound ZnSiP(2) and commercially available CdSe:Cu were obtained using this technique. The results reveal structural details not reported before.

A four-variable model for the pattern-forming mechanism in Hydra.

A generalized Gierer-Meinhardt model has been used to account for the transplantation experiments in Hydra. In this model, a cross inhibition between the two organizing centres (namely, head and foot) are assumed to be the only mode of interaction in setting up a stable morphogen distribution for the pattern formation in Hydra.