Heat stress-activated, calcium-dependent nitric oxide synthase in sponges.

The presence of Ca(2+)-dependent, heat-stress-activated nitric oxide synthase (NOS) activity in peculiarly shaped, fusiform, and dendritic sponge cells is described for the first time. The NOS activity was evidenced evaluating the conversion of radioactive citrulline from [(14)C]arginine in intact cells from two different species that are phylogenetically unrelated in the class of Demospongiae: Axinella polypoides and Petrosia ficiformis. The production of nitrogen monoxide (NO) was confirmed by electron paramagnetic resonance analysis, and the histochemistry technique of NADPH diaphorase showed a specific localization of NOS activity in a particular network of dendritic cells in the sponge parenchyma. Sponges are the most primitive metazoan group; their evolution dates back 600 million years. The presence of environmental stress-activated NOS activity in these organisms may prove to be the most ancient NO-dependent signaling network in the animal kingdom.     

Nickel Uptake by Pseudomonas aeruginosa: Role of Modifying Factors

Pseudomonas aeruginosa cells growing in minimal medium were 40-fold more sensitive to Ni²⁺ than cells growing in enriched medium, suggesting a possible protective role of medium ingredients. Likewise, cells pre-grown in enriched medium showed a high K _m (6.15 mM) and increased Ni²⁺ uptake (950 nmol mg⁻¹ protein, 1h) over cells pre-sown in minimal medium (K _m , 0.48 mM; 146 nmol mg⁻¹ protein, 1 h). The overall pattern indicates that cells pre-grown in enriched medium were characterized by having lowered affinity towards Ni²⁺ than those with minimal medium background. The enhanced Ni²⁺ uptake by enriched medium-grown cells can be correlated with the improved metabolic state of the cells. Ni²⁺ uptake was optimum at neutrality (pH 7.0). A major Ni²⁺ transport system was competitively inhibited by Mg²⁺, Zn²⁺, Cd²⁺, or Co²⁺ (400 μM each). Noticeably, a minor Ni²⁺ transport pathway was still operative even in the higher concentration range of Mg²⁺ (4 mM and 40 mM). The stimulation of Ni²⁺ uptake monitored in the presence of different carbon sources (0.5% wt/vol, each) showed the sequence: glucose (1.6-fold) > phenol = gallic acid (1.5-fold). Succinate, in comparison, reduced Ni²⁺ uptake (0.5-fold) possibly because of its acting as a metal chelator as well. Sensitivity of Ni²⁺ transport towards methyl viologen, azide, 2-4 DNP, and DCCD suggested that transport was energy-linked. Received: 13 January 1998 / Accepted: 21 May 1998     

Homologs from sulfur oxidation (Sox) and methanol dehydrogenation (Xox) enzyme systems collaborate to give rise to a novel pathway of chemolithotrophic tetrathionate oxidation

The SoxXAYZB(CD)₂‐mediated pathway of bacterial sulfur‐chemolithotrophy explains the oxidation of thiosulfate, sulfide, sulfur and sulfite but not tetrathionate. Advenella kashmirensis, which oxidizes tetrathionate to sulfate, besides forming it as an intermediate during thiosulfate oxidation, possesses a soxCDYZAXOB operon. Knock‐out mutations proved that only SoxBCD is involved in A. kashmirensis tetrathionate oxidation, whereas thiosulfate‐to‐tetrathionate conversion is Sox independent. Expression of two glutathione metabolism‐related proteins increased under chemolithotrophic conditions, as compared to the chemoorganotrophic one. Substrate‐dependent oxygen consumption pattern of whole cells, and sulfur‐oxidizing enzyme activities of cell‐free extracts, measured in the presence/absence of thiol inhibitors/glutathione, corroborated glutathione involvement in tetrathionate oxidation. Furthermore, proteome analyses detected a sulfite:acceptor oxidoreductase (SorAB) exclusively under chemolithotrophic conditions, while expression of a methanol dehydrogenase (XoxF) homolog, subsequently named thiol dehydrotransferase (ThdT), was found to increase 3‐ and 10‐fold during thiosulfate‐to‐tetrathionate conversion and tetrathionate oxidation respectively. A thdT knock‐out mutant did not oxidize tetrathionate but converted half of the supplied 40 mM S‐thiosulfate to tetrathionate. Knock‐out of another thiosulfate dehydrogenase (tsdA) gene proved that both ThdT and TsdA individually converted ～ 20 mM S‐thiosulfate to tetrathionate. The overexpressed and isolated ThdT protein exhibited PQQ‐dependent thiosulfate dehydrogenation, whereas its PQQ‐independent thiol transfer activity involving tetrathionate and glutathione potentially produced a glutathione:sulfodisulfane adduct and sulfite. SoxBCD and SorAB were hypothesized to oxidize the aforesaid adduct and sulfite respectively.     

Colocalization of atrial natriuretic factor (ANF) and estradiol in hypothalamic neurons by combined autoradiography-immunohistochemistry

Summary The distribution of estrogen target neurons which contain atrial natriuretic factor (ANF) in female rat hypothalamus was investigated by thaw-mount autoradiography combined with immunocytochemistry using tritium-labeled estradiol and antibodies against ANF. Colocalization of the two hormones was found in the arcuate nucleus, periventricular nucleus, lateral ventromedial nucleus, ventral premammillar nucleus and lateral basal hypothalamus. The percentage of ANF containing cells which concentrate estradiol varies among the different hypothalamic nuclei with the highest number of ANF-positive cells showing nuclear concentration of ³H-estradiol (80–90%) in the nucleus premammillaris ventralis, but less (5–15%) in the other nuclei. These data, together with topographical correspondence in extrahypothalamic brain regions between sites of action of estradiol and production of ANF, suggest extensive interrelationships and modulatory effects of estradiol on ANF production and secretion in the brain, similar to the atrium of the heart.     

Coumarin or benzoxazinone based novel carbonic anhydrase inhibitors: synthesis,molecular docking and anticonvulsant studies

Among many others, coumarin derivatives are known to show human carbonic anhydrase (hCA) inhibitory activity. Since hCA inhibition is one of the underlying mechanisms that account for the activities of some antiepileptic drugs (AEDs), hCA inhibitors are expected to have anti-seizure properties. There are also several studies reporting compounds with an imidazole and/or benzimidazole moiety which exert these pharmacological properties. In this study, we prepared fifteen novel coumarin-bearing imidazolium and benzimidazolium chloride, nine novel benzoxazinone-bearing imidazolium and benzimidazolium chloride derivatives and evaluated their hCA inhibitory activities and along with fourteen previously synthesized derivatives we scanned their anticonvulsant effects. As all compounds inhibited purified hCA isoforms I and II, some of them also proved protective against Maximal electroshock seizure (MES) and ScMet induced seizures in mice. Molecular docking studies with selected coumarin derivatives have revealed that these compounds bind to the active pocket of the enzyme in a similar fashion to that previously described for coumarin derivatives.     

Trends in Malaria in Odisha,India—An Analysis of the 2003–2013 Time-Series Data from the National Vector Borne Disease Control Program

Background

Although Odisha is the largest contributor to the malaria burden in India, no systematic study has examined its malaria trends. Hence, the spatio-temporal trends in malaria in Odisha were assessed against the backdrop of the various anti-malaria strategies implemented in the state.

Methods

Using the district-wise malaria incidence and blood examination data (2003–2013) from the National Vector Borne Disease Control Program, blood examination-adjusted time-trends in malaria incidence were estimated and predicted for 2003–2013 and 2014–2016, respectively. An interrupted time series analysis using segmented regression was conducted to compare the disease trends between the pre (2003–2007) and post-intensification (2009–2013) periods. Key-informant interviews of state stakeholders were used to collect the information on the various anti-malaria strategies adopted in the state.

Results

The state annual malaria incidence declined from 10.82/1000 to 5.28/1000 during 2003–2013 (adjusted annual decline: -0.54/1000, 95% CI: -0.78 to -0.30). However, the annual blood examination rate remained almost unchanged from 11.25% to 11.77%. The keyinformants revealed that intensification of anti-malaria activities in 2008 led to a more rapid decline in malaria incidence during 2009–2013 as compared to that in 2003–2007 [adjusted decline: -0.83 (-1.30 to -0.37) and -0.27 (-0.41 to -0.13), respectively]. There was a significant difference in the two temporal slopes, i.e., -0.054 (-0.10 to -0.002, p = 0.04) per 1000 population per month, between these two periods, indicating almost a 200% greater decline in the post-intensification period. Although, the seven southern high-burden districts registered the highest decline, they continued to remain in that zone, thereby, making the achievement of malaria elimination (incidence <1/1000) unlikely by 2017.

Conclusion

The anti-malaria strategies in Odisha, especially their intensification since 2008, have helped improve its malaria situation in recent years. These successful measures need to be sustained and perhaps intensified further for eliminating malaria from Odisha.     

Meiofauna associated with vermetid reefs: the role of macroalgae in increasing habitat size and complexity

Coral Reefs - We present the first dataset of meiofauna associated with vermetid reefs (biogenic constructions of Mediterranean intertidal habitat) in two areas along the northern coast of Sicily,...     

A multiscale model to predict current absolute risk of femoral fracture in a postmenopausal population

Osteoporotic hip fractures are a major healthcare problem. Fall severity and bone strength are important risk factors of hip fracture. This study aims to obtain a mechanistic explanation for fracture risk in dependence of these risk factors. A novel modelling approach is developed that combines models at different scales to overcome the challenge of a large space–time domain of interest and considers the variability of impact forces between potential falls in a subject. The multiscale model and its component models are verified with respect to numerical approximations made therein, the propagation of measurement uncertainties of model inputs is quantified, and model predictions are validated against experimental and clinical data. The main results are model predicted absolute risk of current fracture (ARF0) that ranged from 1.93 to 81.6% (median 36.1%) for subjects in a retrospective cohort of 98 postmenopausal British women (49 fracture cases and 49 controls); ARF0 was computed up to a precision of 1.92 percentage points (pp) due to numerical approximations made in the model; ARF0 possessed an uncertainty of 4.00 pp due to uncertainties in measuring model inputs; ARF0 classified observed fracture status in the above cohort with AUC = 0.852 (95% CI 0.753–0.918), 77.6% specificity (95% CI 63.4–86.5%) and 81.6% sensitivity (95% CI 68.3–91.1%). These results demonstrate that ARF0 can be computed using the model with sufficient precision to distinguish between subjects and that the novel mechanism of fracture risk determination based on fall dynamics, hip impact and bone strength can be considered validated.