Effect of boundary type and season on predatory arthropods associated with field margins on New Zealand farmland

Pitfall traps were used to monitor predatory arthropod numbers along two types of field boundary, a post and wire fence line and a Cupressus macrocarpa hedge, along the same paddock margin in Canterbury, New Zealand, over 24 months. The seven most abundant predator groups recorded were: Araneae > Phalangiidae > Staphylinidae > Coccinellidae > Chilopoda > Hemerobiidae > Carabidae. Araneae, Phalangiidae, Staphylinidae, Chilopoda and Hemerobiidae were found in larger numbers at the wire fence than at the hedge site, whereas the numbers of Carabidae and Coccinellidae adults exhibited no field margin preference. However, more species of Araneae and Staphylinidae were caught at the hedge site, whereas species richness of carabid beetles was greatest at the wire fence. Principal component analysis clearly separated the samples collected from the two habitats based on the assemblages of Araneae, Staphylinidae and Carabidae, and certain species in each of these taxonomic groups appeared to be particularly associated with one boundary type or the other. All the main taxonomic groups exhibited clear seasonal patterns, with distinct peaks in abundance occurring at certain times of the year. The results of the study reinforce the idea that management of field boundaries can be used to manipulate the type and abundance of particular groups of predatory arthropods, and that seasonal patterns should be taken into account in schemes of integrated pest management so that any adverse effects of biocide application on these beneficial species may be minimised.     

Automated and assisted RNA resonance assignment using NMR chemical shift statistics

The three-dimensional structure determination of RNAs by NMR spectroscopy relies on chemical shift assignment, which still constitutes a bottleneck. In order to develop more efficient assignment strategies, we analysed relationships between sequence and ¹H and ¹³C chemical shifts. Statistics of resonances from regularly Watson–Crick base-paired RNA revealed highly characteristic chemical shift clusters. We developed two approaches using these statistics for chemical shift assignment of double-stranded RNA (dsRNA): a manual approach that yields starting points for resonance assignment and simplifies decision trees and an automated approach based on the recently introduced automated resonance assignment algorithm FLYA. Both strategies require only unlabeled RNAs and three 2D spectra for assigning the H2/C2, H5/C5, H6/C6, H8/C8 and H1′/C1′ chemical shifts. The manual approach proved to be efficient and robust when applied to the experimental data of RNAs with a size between 20 nt and 42 nt. The more advanced automated assignment approach was successfully applied to four stem-loop RNAs and a 42 nt siRNA, assigning 92–100% of the resonances from dsRNA regions correctly. This is the first automated approach for chemical shift assignment of non-exchangeable protons of RNA and their corresponding ¹³C resonances, which provides an important step toward automated structure determination of RNAs.     

Hspa4l-deficient mice display increased incidence of male infertility and hydronephrosis development

The Hspa4l gene, also known as Apg1 or Osp94, belongs to the HSP110 heat shock gene family, which includes three genes encoding highly conserved proteins. This study shows that Hspa4l is expressed ubiquitously and predominantly in the testis. The protein is highly expressed in spermatogenic cells, from late pachytene spermatocytes to postmeiotic spermatids. In the kidney, the protein is restricted to cortical segments of distal tubules. To study the physiological role of this gene in vivo, we generated mice deficient in Hspa4l by gene targeting. Hspa4l-deficient mice were born at expected ratios and appeared healthy. However, approximately 42% of Hspa4l(-/-) male mice suffered from fertility defects. Whereas the seminiferous tubules of Hspa4l(-/-) testes contained all stages of germ cells, the number of mature sperm in the epididymis and sperm motility were drastically reduced. The reduction of the sperm count was due to the elimination of a significant number of developing germ cells via apoptosis. No defects in fertility were observed in female mutants. In addition, 12% of null mutant mice developed hydronephrosis. Concentrations of plasma and urine electrolytes in Hspa4l(-/-) mice were similar to wild-type values, suggesting that the renal function was not impaired. However, Hspa4l(-/-) animals were preferentially susceptible to osmotic stress. These results provide evidence that Hspa4l is required for normal spermatogenesis and suggest that Hspa4l plays a role in osmotolerance.     

Unraveling interactions: do temperature and competition with native species affect the performance of the non-indigenous sun coral Tubastraea coccinea?

Coral Reefs - The impact of invasive species has been increasing in recent decades due to globalization, threatening marine biodiversity. Tubastraea spp. (sun corals) have been spreading worldwide,...     

Sources of fish in the ephemeral western iishana region of the Cuvelai–Etosha Basin in Angola and Namibia

The triangle between the Kavango and Kunene rivers is drained by the Cuvelai, an ephemeral and deltaic drainage system covering more than 100 000 km². In good rainfall years, the area becomes populated by fish communities dominated by five species migrating southward towards the endorheic Etosha Pan, the basin’s terminal sump. When water dries up, fish subsequently die-off and their sudden appearance in rainy years has captivated scientists for decades. The current study was prompted by hitherto untapped indigenous knowledge through narratives of opportunistic fish harvesting of migrating fish at temporary connections between the Kunene River and the Cuvelai- Etosha Basin. A reconnaissance fish survey in 2017 was complemented by digital satellite images and elevation data analyses. Results support the presence of at least three major ephemeral fish migration routes. The dominant fish genera migrating upstream in Kunene tributaries comprise Enteromius, Oreochromis and Clarias, all eurytopic and known to undertake upstream, lateral and downstream migrations on floodplains. Although other notable fish refugia in the Cuvelai–Etosha Basin are yet to be identified, there is a necessity for the protection and management of these migration routes in tandem with studies on the nature and extent of this inter-basin fish migration under climate change and variability.     

Agrivoltaics—The Perfect Fit for the Future of Organic Photovoltaics

This Essay presents a possible pathway for the advancement of organic photovoltaics toward broader commercial success and enlarged market size. This vision aims at broad scale applications in photovoltaic greenhouses and polytunnels, which harvest those portions of the solar spectrum that are not used or required by plants. Based on the assumptions of the Shockley–Queisser–Limit, respectively detailed balance, and the additional postulation of using no absorption in the visible part of the AM 1.5G solar spectrum a power conversion efficiency of ≈17% is theoretically predicted. The suggestion is supported by the existence of a number of organic compounds, which already exhibit a good spectral compatibility with the typical photosynthetic action spectrum of chloroplasts. It is hoped that more suitable materials development shall be triggered and fertilized as a result of this Essay.     

PHOTOINHIBITION IN RED ALGAL SPECIES WITH DIFFERENT CAROTENOID PROFILES1

Members of the Rhodophyta present different carotenoid profiles. In a majority of the species, lutein constitutes >50% of the total carotenoid content, while in other species, it is replaced by zeaxanthin or antheraxanthin. Given that carotenoids have specific roles in photoprotection, different carotenoid profiles of red algae species could be related to their capacity to cope with photoinhibitory stress. Therefore, in the present work, the sensitivity to light stress of red algal species with different carotenoid profiles was investigated. Photoinhibition of photosynthesis induced by high‐light stress and the subsequent recovery in dim‐light conditions was measured using maximal PSII quantum efficiency (F_v/F_m). The degree of decrease and recovery of F_v/F_m and their respective kinetics were related to the carotenoid profile of the species. Although no relationship between sensitivity to high‐light stress and the carotenoid profile was observed, there were clear carotenoid profile‐related differences in the decrease and recovery kinetics. In species with zeaxanthin or antheraxanthin as the major carotenoid, F_v/F_m reduction and recovery was principally associated with slowly activated and relaxed processes. In contrast, in species with lutein as the major carotenoid, rapidly activated processes appear to play a major role in the down‐regulation of photosynthesis during light‐stress conditions. In these species, the repair of D1 is also important during light‐stress conditions. This finding could imply differential expression of mechanisms involved in photoprotection in red algae that seems to be related to the carotenoid profile of the species.