High levels of polyandry, but limited evidence for multiple paternity, in wild populations of the western rock lobster (Panulirus cygnus)

Polyandry, where multiple mating by females results in the temporal and spatial overlap of ejaculates from two or more males, is taxonomically widespread and occurs in varying frequencies within and among species. In decapods (crabs, lobsters, crayfish, and prawns), rates of polyandry are likely to be variable, but the extent to which patterns of multiple paternity reflect multiple mating, and thus are shaped by postmating processes that bias fertilization toward one or a subset of mated males, is unclear. Here, we use microsatellite markers to examine the frequency of multiple mating (the presence of spermatophores from two or more males) and patterns of paternity in wild populations of western rock lobster (Panulirus cygnus). Our data confirm that >45% of females had attached spermatophores arising from at least two males (i.e., confirming polyandry), but we found very limited evidence for multiple paternity; among 24 clutches sampled in this study, only two arose from fertilizations by two or more males. Single inferred paternal genotypes accounted for all remaining progeny genotypes in each clutch, including several instances when the mother had been shown to mate with two or more males. These findings highlight the need for further work to understand whether polyandry is adaptive and to uncover the mechanisms underlying postmating paternity biases in this system.

Sample-to-answer on molecular diagnosis of bacterial infection using integrated lab--on--a--disc

Sepsis by bacterial infection causes high mortality in patients in intensive care unit (ICU). Rapid identification of bacterial infection is essential to ensure early appropriate administration of antibiotics to save lives of patients, yet the present benchtop molecular diagnosis is time-consuming and labor-intensive, which limits the treatment efficiency especially when the number of samples to be tested is extensive. Therefore, we hereby report a microfluidic platform lab-on-a-disc (LOAD) to provide a sample-to-answer solution. Our LOAD customized design of microfluidic channels allows automation to mimic sequential analytical steps in benchtop environment. It relies on a simple but controllable centrifugation force for the actuation of samples and reagents. Our LOAD system performs three major functions, namely DNA extraction, isothermal DNA amplification and real-time signal detection, in a predefined sequence. The disc is self-contained for conducting sample heating with chemical lysis buffer and silica microbeads are employed for DNA extraction from clinical specimens. Molecular diagnosis of specific target bacteria DNA sequences is then performed using a real-time loop-mediated isothermal amplification (RT-LAMP) with SYTO-9 as the signal reporter. Our LOAD system capable of bacterial identification of Mycobacterium tuberculosis (TB) and Acinetobacter baumanii (Ab) with the detection limits 103cfu/mL TB in sputum and 102cfu/mL Ab in blood within 2h after sample loading. The reported LOAD based on an integrated approach should address the growing needs for rapid point-of-care medical diagnosis in ICU.

Loss mitigation in plasmonic solar cells: aluminium nanoparticles for broadband photocurrent enhancements in GaAs photodiodes

We illustrate the important trade-off between far-field scattering effects, which have the potential to provide increased optical path length over broad bands, and parasitic absorption due to the excitation of localized surface plasmon resonances in metal nanoparticle arrays. Via detailed comparison of photocurrent enhancements given by Au, Ag and Al nanostructures on thin-film GaAs devices we reveal that parasitic losses can be mitigated through a careful choice of scattering medium. Absorption at the plasmon resonance in Au and Ag structures occurs in the visible spectrum, impairing device performance. In contrast, exploiting Al nanoparticle arrays results in a blue shift of the resonance, enabling the first demonstration of truly broadband plasmon enhanced photocurrent and a 22% integrated efficiency enhancement.

Peptide-functionalized microfabricated structures for improved on-chip neuronal adhesion

Extracellular, high signal-to-noise ratio recordings from electrogenic cells require a tight coupling between the cellular membrane and the recording electrode. Self assembled monolayers (SAMs) of alkanethiols functionalized with peptides were used in combination with micro- and nano-structured features on the sensor surface. This combination of surface chemistry and topography triggers a phagocytosis-like engulfment and ensures tight coupling. In this paper we report the results concerning usage of different SAMs and the influence of the peptide concentration towards cell adhesion and outgrowth. Later on, the optimized peptide functionalized SAMs were applied on micro- and nano-structured sensor surfaces. As a result, phagocytosis-like events could be shown using focused ion beam SEM and confocal fluorescence imaging.

Energetic contributions for the formation of TAT/TAT, TAT/CGC(+), and CGC(+)/CGC(+) base triplet stacks

We used a combination of spectroscopic and calorimetric techniques to determine complete thermodynamic profiles accompanying the folding of a set of triple helices and control duplexes. Specifically, we studied the sequences: d(A(7)C(5)T(7)C(5)T(7)), d(A(6)C(5)T(6)C(5)T(6)), d(A(6)C(5)T(6)), d(AGAGAGAC(5)TCTCTCTC(5)TCTCTCT), d(AGAGAC(5)TCTCTC(5)TCTCT), d(AGAGAC(5)TCTCTC(2)), d(AAGGAC(5)TCCTTC(5)TTCCT), d(AGGAAC(5)TTCCTC(5)TCCTT), and d(GAAAGC(5)CTTTCC(5)CTTTC). Circular dichroism spectroscopy indicated that all triplexes and duplexes are in the "B" conformation. DSC melting experiments revealed that the formation of triplexes is accompanied by a favorable free energy change, which arises from the compensation of a large and favorable enthalpic contribution with an unfavorable entropic contribution. Comparison of the thermodynamic profiles of these triplexes yielded enthalpic contributions of -24 kcal/mol, -23 kcal/mol, and -22 kcal/mol for the formation of TAT/TAT, TAT/CGC(+), and CGC(+)/CGC(+) base triplet stacks, respectively. UV melts as a function of sodium concentration show sodium ions stabilize the triplexes that contain only TAT triplets but destabilize the triplexes that contain CGC(+) triplets. UV melts as a function of pH indicate that the protonation of the third strand and loop cytosines stabilizes the triplexes that contain CGC(+) and TAT triplets, respectively. Our overall results suggest that the triplex to duplex transition of triplexes that contain CGC(+) triplets is accompanied by a release of protons and an uptake of sodium, while their duplex to random coil transition is accompanied by a release of sodium ions. A consequence of this opposite sodium dependence is that their coupled transitions are nearly independent of sodium concentration but are dependent on the experimental pH.

Disposition of the antipsychotic agent CI-1007 in rats, monkeys, dogs, and human cytochrome P450 2D6 extensive metabolizers. Species comparison and allometric scaling

The disposition of CI-1007 (I), an antipsychotic dopamine agonist, was studied after iv or po administration to rats, monkeys, and dogs and po administration to human cytochrome P450 2D6 extensive metabolizers (EMs). I was extensively metabolized after po administration, with high hepatic clearance (CL) values and negligible urinary excretion. Values for systemic plasma CL (28-40 ml/min/kg) suggested hepatic plasma flow-limited CL. The oral CL of I was similar among the species. Strong correlation was achieved in interspecies scaling for CL. After oral administration of [14C]I, the major route of 14C elimination in rats was in the bile (64%), followed by feces (29%) and urine (3.2%). Fecal excretion (64%) was the major route of 14C elimination in monkeys, followed by urine (14%). Three hydroxy metabolites, i.e. PD 147693 (II), PD 149394 (III), and PD 155144 (IV), and two sulfates, i.e. PD 163637 (VI) and PD 163639 (VIII), were identified in monkey plasma, urine, or feces. VIII was the major metabolite excreted in monkey urine, and VI was the major component in feces. Trace amounts of II, VI, and VIII were detected in the plasma and urine of human EMs but not in rats or dogs. II is an active metabolite that was present in all species. After oral administration, observed maximal plasma concentration and AUC values for II were higher than the corresponding values for I in dog plasma, approximately 20-40% of the values for I in monkeys and human EMs, and <5% of the values for I in rat plasma. Although the metabolic profiles differ among species, strong correlation was achieved in allometric scaling because the elimination of I from the body is mainly limited by hepatic blood flow.

2,2'-Dithiobisbenzamides and 2-benzisothiazolones, two new classes of antiretroviral agents: SAR and mechanistic considerations

Substituted 2,2'-dithiobisbenzamides and 2-benzisothiazolones were prepared and shown to possess low microM activity with high therapeutic indices against HIV-1, HIV-2 and SIV in cell culture. The mechanism of antiviral action was determined to be directed toward the nucleocapsid protein (NCp7), which contains two zinc fingers and plays vital roles in the viral life cycle. The "active sulfides" of this study cause the extrusion of zinc from these zinc fingers. Structure-activity relationships of the 2,2'-dithiobisbenzamides reveal that the disulfide bond and the ortho benzamide functional groups are essential for activity, with the best compounds having a carboxylic acid, carboxamide, or sulfonamide substituent. The 2-benzisothiazolones are formed from the disulfides both chemically and in vivo and their SAR mimics that of the 2,2'-dithiobisbenzamides. The antiviral activity of the disulfides may require cyclization to the isothiazolones. Two agents, PD 159206 and PD 161374, which showed good antiviral activity, physical properties, and excellent pharmacokinetics in mice, were selected for advanced studies.