The influence of growth rate on the size of migrating female eels in Lake Ellesmere, New Zealand

Lake Ellesmere, a large coastal lake in the South Island of New Zealand, supports an important commercial eel fishery, based mainly on migrating (silver) male Anguilla australis . Lengths of silver female eels from samples collected in 1942, 1974–1982 and 1998–1999 showed an initial decline between 1942 and 1974 but an increase from 1979 onwards. Back-calculated growth rates of 50 female silver eels caught in 1998 showed that most (90%) exhibited a period of accelerated linear growth commencing at lengths between 380 and 660 mm (mean 598 mm); this accelerated growth coincided with a change in diet to piscivory. The onset of maturity was more closely associated with length than age, condition, or growth rate. The increase in average length of female silver eels of 250 mm over the past 20 years is consistent with the hypothesis that female eels adopt a size-maximizing growth strategy to ensure maximum fecundity; this is the first time this hypothesis has been demonstrated from temporal changes within a single population.     

Immunohistochemical demonstration of renin in the juxtaglomerular apparatus of three Bufo species

Summary The cellular localization of renin was examined in the kidneys of some amphibians of the genus Bufo by immunoperoxidase and immunofluorescence techniques with an antiserum to renin isolated from the submandibular gland of the mouse. Immunoreactivity could be demonstrated in the media cells of the afferent arterioles (juxtaglomerular cells) close to as well as at great distance from the glomeruli. Occasionally, media cells of larger arterial vessels were also stained. The immunohistochemical data seem to be in accordance with earlier results obtained with a modified silver impregnation technique (Movat's staining procedure) used for the visualization of juxtaglomerular cells in non-mammalian vertebrates. Mouse kidney tissue, studied for purposes of comparison, showed renin-immunoreactivity as described by earlier investigators, i.e., immunoreactive staining in the afferent arterioles near the glomeruli and in the proximal tubule cells.     

Construction of a genetic linkage map for silver carp (Hypophthalmichthys molitrix)

For silver carp (Hypophthalmichthys molitrix), a combined microsatellite (or simple sequence repeat) and amplified fragment length polymorphism (AFLP) sex average linkage map was constructed. A total of 483 markers (245 microsatellites and 238 AFLPs) were assigned to 33 linkage groups. The map spanned 1352.2 cM, covering 86.4% of the estimated genome size of silver carp. The maximum and average spaces between 420 loci were 21.5 cM and 3.2 cM, respectively. The length of linkage groups ranged from 3.6 cM to 98.5 cM with an average of 41.0 cM. The number of markers per group varied from 2 to 44 with an average of 14.6. The AFLP markers significantly improved the integrity of microsatellite-based linkage groups and increased the genome coverage and marker evenness. A genome-wide recombination suppression was observed in male. In an extreme case, six microsatellites co-segregated in male, but spanned a 45.1 cM region in female.     

Ethylene inhibitors promote in vitro regeneration of cowpea (Vigna unguiculata L.)

Summary Ethylene is a plant growth regulator that is known to influence in vitro morphogenesis. This study investigated the effects of three ethylene inhibitors, silver nitrate (AgNO₃), 2,5-norbornadiene, and cobalt chloride (CoCl₂), on the regeneration of cowpea from cotyledon explants. Significant increases in the percentage of regeneration occurred as a result of adding either 50 μM AgNO₃ or 100 μM 2,5-norbornadiene. The number of shoots produced per explant was enhanced by adding 25 μM CoCl₂ or 100 μM norbornadiene. Maximum shoot elongation was obtained with 25 μM of either CoCl₂ or norbornadiene. The effect of the duration of exposure to AgNO₃ was also determined. The greatest percent regeneration was obtained with the addition of 60 μM AgNO₃ either to both the initiation and regeneration stages, or to only the regeneration stage. The promotive effects on organogenesis in response to ethylene inhibitors suggests an important role for ethylene in the process of in vitro morphogenesis of cowpea and may contribute to its normally low regeneration frequency.     

Gold Toning Improves the Visualization of Nucleolar Organizer Regions in Paraffin Embedded Tissues

A modification of the silver colloid technique for staining nucleolar organizer regions in paraffin embedded tissues is described. This modification involves the application of a gold toning step with subsequent gold reduction, if necessary, following incubation of sections in the standard silver colloid solution. Silver stained nucleolar organizer regions (AgNORs) in toned sections are more sharply delineated when compared to untoned controls. in high grade tumors the addition of the toning step results in significantly higher AgNOR counts due to the ability to discriminate more easily individual AgNORs in argyrophilic aggregates within the nucleus. It is recommended, because of enhanced visualization, that this modification of the silver colloid technique be used in studies involving quantification of AgNORs in tissue sections.     

All‐Solution‐Processed Silver Nanowire Window Electrode‐Based Flexible Perovskite Solar Cells Enabled with Amorphous Metal Oxide Protection

Silver nanowire (AgNW)‐based transparent electrodes prepared via an all‐solution‐process are proposed as bottom electrodes in flexible perovskite solar cells (PVSCs). To enhance the chemical stability of AgNWs, a pinhole‐free amorphous aluminum doped zinc oxide (a‐AZO) protection layer is deposited on the AgNW network. Compared to its crystalline counterpart (c‐AZO), a‐AZO substantially improves the chemical stability of the AgNW network. For the first time, it is observed that inadequately protected AgNWs can evanesce via diffusion, whereas a‐AZO secures the integrity of AgNWs. When an optimally thick a‐AZO layer is used, the a‐AZO/AgNW/AZO composite electrode exhibits a transmittance of 88.6% at 550 nm and a sheet resistance of 11.86 Ω sq^?1, which is comparable to that of commercial fluorine doped tin oxide. The PVSCs fabricated with a configuration of Au/spiro‐OMeTAD/CH₃NH₃PbI₃/ZnO/AZO/AgNW/AZO on rigid and flexible substrates can achieve power conversion efficiencies (PCEs) of 13.93% and 11.23%, respectively. The PVSC with the a‐AZO/AgNW/AZO composite electrode retains 94% of its initial PCE after 400 bending iterations with a bending radius of 12.5 mm. The results clearly demonstrate the potential of AgNWs as bottom electrodes in flexible PVSCs, which can facilitate the commercialization and large‐scale deployment of PVSCs.