Effects of geometry on transmission and sensing potential of tapered fiber sensors

Geometry of tapered fiber sensors critically affects the response of an evanescent field sensor to cell suspensions. Single-mode fibers (nominally at 1300 nm) were tapered to symmetric or asymmetric tapers with diameters in the range of 3–20 μm, and overall lengths of 1–7 mm. Their transmission characteristics in air, water and in the presence of Escherichia coli (JM101 strain) at concentrations of 100, 1000, 7000 and 7 million cells/mL were measured in the 400–800 nm range and gave rich spectral data that lead to the following conclusions. (1) No change in transmission was observed due to E. coli with tapers that showed no relative change in transmission in water compared to air. (2) Tapers that exhibited a significant difference in transmission in water compared to air gave weak response to the presence of the E. coli. Of these, tapers with low waist diameters (6 μm) showed sensitivity to E. coli at 7000 cells/mL and higher concentration. (3) Tapers that showed modest difference in water transmission compared to air, and those that had small waist diameters gave excellent response to E. coli at 100–7000 cells/mL. In addition, mathematical modeling showed that: (1) at low wavelength (470 nm) and small waist diameter (6 μm), transmission with water in the waist region is higher than in air. (2) Small changes in waist diameter (0.05 μm) can cause larger changes in transmission at 470 nm than at 550 nm at waist diameter of 6 μm. (3) For the same overall geometry, a 5.5 μm diameter taper showed larger refractive index sensitivity compared to a 6.25 μm taper at 470 nm.     

Synthesis and appetite suppressant activity of 1-aryloxy-2-substituted aminomethyltetrahydronaphthalenes as conformationally rigid analogues of fluoxetine

Several 1-aryloxy-2-substituted aminomethyltetrahydronaphthalenes (7-21) as conformationally rigid analogues of fluoxetine were synthesized and evaluated for their anorexigenic and antidepressant activities. For SAR studies the related acyclic analogues (22-27) were also prepared. Out of the 21 synthesized compounds, 10 compounds (9, 10, 11, 15, 16, 18, 21, 22, 23 and 27) exhibited significant anorexigenic activity (at 75 micromol/kg). Interestingly, all the compounds (7-20, 22-26) were devoid of antidepressant effect, except for compounds 21 and 27 in which the antidepressant activity was retained. Compound 16 emerged as the most active compound of the series with better anorexigenic activity (97.92%) compared to fluoxetine (76.25%) and even with a clinically used drug sibutramine, thus providing a new structural lead for appetite suppressants.     

Insufficient rest or sleep and its relation to cardiovascular disease, diabetes and obesity in a national, multiethnic sample

Background

A new question on insufficient rest/sleep was included in the 2008 Behavioral Risk Factor Surveillance System (BRFSS) for the 50 states, District of Columbia, and three US territories. No previous study, however, has examined perceived insufficient rest/sleep in relation to cardiovascular disease (CVD) or diabetes mellitus. We examined the association between self-reported insufficient rest/sleep and CVD, diabetes, and obesity in a contemporary sample of US adults.

Methods

Multiethnic, nationally representative, cross-sectional survey (2008 BRFSS) participants were >20 years of age (n = 372, 144, 50% women). Self-reported insufficient rest/sleep in the previous month was categorized into four groups: zero, 1–13, 14–29, and 30 days. There were five outcomes: 1) any CVD, 2) coronary heart disease (CHD), 3) stroke, 4) diabetes mellitus, and 5) obesity (body mass index≥30 kg/m²). We employed multivariable logistic regression to calculate odds ratio (OR), (95% confidence interval (CI), of increasing categories of insufficient rest/sleep, taking zero days of insufficient rest/sleep as the referent category.

Principal Findings

Insufficient rest/sleep was found to be associated with 1) any CVD, 2) CHD, 3) stroke, 4) diabetes mellitus, and 5) obesity, in separate analyses. Compared to those reporting zero days of insufficient sleep (referent), the OR (95% CI) associated with all 30 days of insufficient sleep was 1.67 (1.55–1.79) for any cardiovascular disease, 1.69(1.56–1.83) for CHD, 1.51(1.36–1.68) for stroke, 1.31(1.21–1.41) for diabetes, and 1.51 (1.43–1.59) for obesity.

Conclusions

In a multiethnic sample of US adults, perceived insufficient rest/sleep was found to be independently associated with CHD, stroke, diabetes mellitus and obesity.     

Effect of surfactants and inducers on increased uricase production under submerged fermentations by Bacillus cereus

Uricase is a clinical enzyme used for the oxidation of uric acid crystals in gout disease. The present study aimed to increase the suitable surfactant-mediated uricase production on induction by different concentrations of inducers. The efficiency of Bacillus cereus to produce extracellular uricase enzyme was studied in uric acid-containing agar plates. Among the studied inducers, uric acid is the potential inducer for uricase production under submerged fermentations (SMF), which induced 19.41?U/ml uricase in medium containing 2.0?g/L of uric acid, however further increase in the uric acid concentration decreased uricase production, which could be because of substrate inhibition. The physical parameters including agitation speed (rpm) and time duration (h) of uricase production were optimized and found to produce optimum uricase at 150?rpm in 26?h of SMF. Among the studied surfactants, nonionic surfactant, polyvinyl alcohol has shown a remarkable increase in the uricase production of 31.58?U/ml, which is a 61% increase under optimized conditions in SMF. The stability of produced uricase was found at pH 7.5 and temperature 30°C. Also the effects of various metal ions (1?mM) on the uricase activity were studied and observed to be inhibitory in nature in the descending order K⁺?>?Ca²⁺?>?Zn²⁺?>?Fe³⁺?>?Ni²⁺?>?Mg²⁺?>?Mn²⁺?>?Cu²⁺.     

Xanthoferrin,the α‐hydroxycarboxylate‐type siderophore of Xanthomonas campestris pv. campestris,is required for optimum virulence and growth inside cabbage

Xanthomonas campestris pv. campestris causes black rot, a serious disease of crucifers. Xanthomonads encode a siderophore biosynthesis and uptake gene cluster xss (Xanthomonas siderophore synthesis) involved in the production of a vibrioferrin‐type siderophore. However, little is known about the role of the siderophore in the iron uptake and virulence of X. campestris pv. campestris. In this study, we show that X. campestris pv. campestris produces an α‐hydroxycarboxylate‐type siderophore (named xanthoferrin), which is required for growth under low‐iron conditions and for optimum virulence. A mutation in the siderophore synthesis xssA gene causes deficiency in siderophore production and growth under low‐iron conditions. In contrast, the siderophore utilization ΔxsuA mutant is able to produce siderophore, but exhibits a defect in the utilization of the siderophore–iron complex. Our radiolabelled iron uptake studies confirm that the ΔxssA and ΔxsuA mutants exhibit defects in ferric iron (Fe³⁺) uptake. The ΔxssA mutant is able to utilize and transport the exogenous xanthoferrin–Fe³⁺ complex; in contrast, the siderophore utilization or uptake mutant ΔxsuA exhibits defects in siderophore uptake. Expression analysis of the xss operon using a chromosomal gusA fusion indicates that the xss operon is expressed during in planta growth and under low‐iron conditions. Furthermore, exogenous iron supplementation in cabbage leaves rescues the in planta growth deficiency of ΔxssA and ΔxsuA mutants. Our study reveals that the siderophore xanthoferrin is an important virulence factor of X. campestris pv. campestris which promotes in planta growth by the sequestration of Fe³⁺.     

Lipid classification, structures and tools

The study of lipids has developed into a research field of increasing importance as their multiple biological roles in cell biology, physiology and pathology are becoming better understood. The Lipid Metabolites and Pathways Strategy (LIPID MAPS) consortium is actively involved in an integrated approach for the detection, quantitation and pathway reconstruction of lipids and related genes and proteins at a systems-biology level. A key component of this approach is a bioinformatics infrastructure involving a clearly defined classification of lipids, a state-of-the-art database system for molecular species and experimental data and a suite of user-friendly tools to assist lipidomics researchers. Herein, we discuss a number of recent developments by the LIPID MAPS bioinformatics core in pursuit of these objectives.     

A LIN28-dependent structural change in pre-let-7g directly inhibits dicer processing

Several recent studies have provided evidence that LIN28, a cytoplasmic RNA-binding protein, inhibits the biogenesis of members of the let-7 microRNA family at the Dicer step in both mammals and Caenorhabditis elegans. However, the precise mechanism of inhibition is still poorly understood. Here we report on an in vitro study, which combined RNase footprinting, gel shift binding assays, and processing assays, to investigate the molecular basis and function of the interaction between the native let-7g precursor (pre-let-7g) and LIN28. We have mapped the structure of pre-let-7g and identified some regions of the terminal loop of pre-let-7g that physically interact with LIN28. We have also identified a conformational change upon LIN28 binding that results in the unwinding of an otherwise double-stranded region at the Dicer processing site of pre-let-7g. Furthermore, we showed that a mutant pre-let-7g that displays an open upper stem inhibited pre-let-7g Dicer processing to the same extent as LIN28. The data support a mechanism by which LIN28 can directly inhibit let-7g biogenesis at the Dicer processing step.     

Coordination polymers and monomers based on new aminocarboxylate ligands: A cadmium(II) polymer containing dimeric aqua-bridged cadmium complex governed by polymeric chain

The synthesis and characterization of novel coordination polymers [Co(HCCB)(H₂O)₂]_n (1), [Zn(HCCB)(H₂O)₂]_n (2), {[Cd(HCCB)₂]·0.5[Cd(μ-H₂O)(H₂O)₄]₂}_n (3) and [Cu(HCCB)(H₂O)₂]_n (4) based on 3-(carboxymethylamino)-4-chlorobenzoic acid (H₃CCB) and mononuclear complexes [Cu(HBCCB)(H₂O)]·H₂O (5), [Co(HBCCB)(H₂O)]·H₂O (6), [Zn(HBCCB)(H₂O)] (7) and [Cd(HBCCB)(H₂O)] (8) containing 3-bis(carboxymethylamino)-4-chlorobenzoic acid (H₃BCCB) have been described. The compounds under investigation have been characterized by elemental analyses, spectral studies and structures of 1-3 and 5 determined crystallographically. Structural data of 1 and 2 revealed that the deprotonated HCCB²⁻ bridges metal centers leading to a double stranded 1D chain. On the other hand, the HCCB²⁻ coordinated thorough carboxylate oxygen and amino nitrogen in 3 to afford a 1D chain whose charge neutrality is maintained by inclusion of aqua-bridged dimer [{Cd(μ-H₂O)(H₂O)₄}₂]⁴⁺. Strong Cu?Cl interaction (2.754 Å) in 5 imposes a coordination geometry that is half-way between the square planar and square pyramidal. The H₃CCB, H₃BCCB and 1-3 and 5 are fluorescent at rt. Thermal studies (TG and DSC) on 1-3 suggested higher stability of 2 relative to 1 and 3 [ΔH_f (kcal/mol), ΔS_f = 152.17, 0.60, 1; 195.56: 0.86, 2; 69.33:0.36, 3].     

Changes in biochemical composition of follicular fluid during reproductive acyclicity in water buffalo (Bubalus bubalis)

This study describes the changes in biochemical composition of follicular fluid during reproductive acyclicity in buffalo. A total of 73 pairs of ovaries collected from 26 reproductively acyclic and 47 reproductively cyclic buffaloes were used in the investigation. Ovarian follicles were classified into small (5.0-6.9 mm), medium (7.0-9.9 mm) and large (≥10.0 mm) sized categories depending upon their diameter. Follicular fluid was aspirated, processed and assayed for glucose, cholesterol, total protein, acid phosphatase and alkaline phosphatase. Glucose concentration was lesser in reproductively acyclic compared to cyclic buffaloes (19.3 ± 2.59 mg/dl compared to 32.6 ± 2.60 mg/dl; P<0.05), mainly due to difference in concentration between small sized follicles (12.4 ± 2.59 mg/dl compared to 28.0 ± 3.32 mg/dl; P<0.05). Cholesterol concentration was also lesser in reproductively acyclic compared to cyclic buffaloes (32.2 ± 2.14 mg/dl compared to 35.5 ± 2.16 mg/dl; P<0.05) and this was related to the lesser concentration found in large follicles (13.8 ± 3.45 mg/dl compared to 37.2 ± 4.10mg/dl; P<0.001). Total protein and acid phosphatase levels were not affected by either the reproductive cyclicity status or the follicular size (4.9 ± 1.07 g/dl to 6.0 ± 0.28 g/dl and 1.2 ± 0.17 U/dl to 2.5 ± 1.22 U/dl, respectively). An increased alkaline phosphatase activity was, however, observed in reproductively acyclic compared to cyclic buffaloes (27.5 ± 3.08 U/dl compared to 14.0 ± 1.09 U/dl; P<0.0001). In conclusion, results of the present study indicate an alteration in the biochemical composition of follicular fluid during reproductive acyclicity in buffalo. The findings provide further support to the notion that poor nutrition is an important factor triggering reproductive acyclicity in buffalo.