The virtue of training: extending phage host spectra against vancomycin-resistant Enterococcus faecium strains using the Appelmans method.

Phage therapy has (re)emerged as a serious possibility for combating multidrug-resistant bacterial infections, including those caused by vancomycin-resistant Enterococcus faecium strains. These opportunistic pathogens belong to a specific clonal complex 17, against which relatively few phages have been screened. We isolated a collection of 21 virulent phages growing on these vancomycin-resistant isolates. Each of these phages harbored a typical narrow plaquing host range, lysing at most 5 strains and covering together 10 strains of our panel of 14 clinical isolates. To enlarge the host spectrum of our phages, the Appelmans protocol was used. We mixed four out of our most complementary phages in a cocktail that we iteratively grew on eight naive strains from our panel, of which six were initially refractory to at least three of the combined phages. Fifteen successive passages permitted to significantly improve the lytic activity of the cocktail, from which phages with extended host ranges within the E. faecium species could be isolated. A single evolved phage able to kill up to 10 of the 14 initial E. faecium strains was obtained, and it barely infected nearby species. All evolved phages had acquired point mutations or a recombination event in the tail fiber genetic region, suggesting these genes might have driven phage evolution by contributing to their extended host spectra.

Extension of Operating Range in Hybrid Cascaded H-Bridge Inverters with Capacitor Voltage Balancing Capability.

In this article, a generalized control scheme is proposed to extend the operating range of three-phase hybrid cascaded H-bridge (HCHB) inverters into various voltage levels without necessitating alterations to the core structure or the integration of additional H-bridge submodules. This study addresses a critical challenge related to capacitor voltage drift at various modulation indices and power factors, which is a serious impediment to various applications. To overcome this challenge, a novel balancing control scheme has been developed based on the injection of two independent offset voltages to simultaneously control the DC-link and flying capacitors. A distinctive aspect of the proposed technique involves adjusting the common reference voltage to attain the nearest level in the same cluster, thereby mitigating the insufficiency of redundant switching states. The effectiveness of the proposed technique to regulate the capacitor voltages at various operating conditions has been verified through simulation and experimental results.

Occurrence of tripletail Lobotes surinamensis (Bloch, 1790) in the inner Bristol Channel, UK.

A specimen of tripletail Lobotes surinamensis (total length: 402 mm, total mass: 1262 g) was caught in the shallow waters of the inner Bristol Channel on September 2, 2019, with this only the second known capture of this species from the British Isles. Given the cosmopolitan distribution of this species, the potential origin of this specimen is uncertain.

New shark in the park: Tiger shark Galeocerdo cuvier observations in the remote South Pacific.

We present the first photographic records of the tiger shark (Galeocerdo cuvier) at the remote Rapa Nui (Easter Island) in the south-east Pacific. Previous anecdotal sightings exist for tiger sharks in this region; however these records have not been reported within the scientific domain. The present sighting occurred in a period of unusually warm sea surface temperature, which has been shown to influence tiger shark range extensions elsewhere. Novel and historic species occurrence records are valuable for determining and predicting species' environmental tolerances, migratory routes, and distributional limits.

Wildfire facilitates upslope advance in a shade-intolerant but not a shade-tolerant conifer.

Wildfires may facilitate climate tracking of forest species moving upslope or north in latitude. For subalpine tree species, for which higher elevation habitat is limited, accelerated replacement by lower elevation montane tree species following fire may hasten extinction risk. We used a dataset of postfire tree regeneration spanning a broad geographic range to ask whether the fire facilitated upslope movement of montane tree species at the montane-to-subalpine ecotone. We sampled tree seedling occurrence in 248 plots across a fire severity gradient (unburned to >90% basal area mortality) and spanning ~500 km of latitude in Mediterranean-type subalpine forest in California, USA. We used logistic regression to quantify differences in postfire regeneration between resident subalpine species and the seedling-only range (interpreted as climate-induced range extension) of montane species. We tested our assumption of increasing climatic suitability for montane species in subalpine forest using the predicted difference in habitat suitability at study plots between 1990 and 2030. We found that postfire regeneration of resident subalpine species was uncorrelated or weakly positively correlated with fire severity. Regeneration of montane species, however, was roughly four times greater in unburned relative to burned subalpine forest. Although our overall results contrast with theoretical predictions of disturbance-facilitated range shifts, we found opposing postfire regeneration responses for montane species with distinct regeneration niches. Recruitment of shade-tolerant red fir declined with fire severity and recruitment of shade-intolerant Jeffrey pine increased with fire severity. Predicted climatic suitability increased by 5% for red fir and 34% for Jeffrey pine. Differing postfire responses in newly climatically available habitats indicate that wildfire disturbance may only facilitate range extensions for species whose preferred regeneration conditions align with increased light and/or other postfire landscape characteristics.

First records of the Pacific sleeper shark Somniosus cf. pacificus in the western tropical Pacific.

Technological advances have enabled the expansion of ocean exploration to include the deep ocean, providing new species observations. Here, the authors present two new observations, captured by deep-sea cameras, of the sleeper shark Somniosus cf. pacificus from the Solomon Islands and Palau. This presents the first observation of S. cf. pacificus in the western Pacific tropics and extends its range about 2000 nautical miles south. The observations presented here provide much-needed information on the range of this species which can help guide future management and conservation actions.

First record of Boulenger's anthias Sacura boulengeri (Heemstra 1973) in the Red Sea.

In November 2020, we observed several individuals and collected one juvenile of an unidentified anthiadine fish (Serranidae) between depths of 250 and 307 m near vertical walls of rocky reefs in the northern Red Sea. Further morphological and molecular analyses revealed that the collected specimen matches Sacura boulengeri, a species previously reported only from the Gulf of Oman to India.

Ocean warming and acidification degrade shoaling performance and lateralization of novel tropical-temperate fish shoals.

Gregarious behaviours are common in animals and provide various benefits such as food acquisition and protection against predators. Many gregarious tropical species are shifting poleward under current ocean warming, creating novel species and social interactions with local temperate taxa. However, how the dynamics of these novel shoals might be altered by future ocean warming and acidification remains untested. Here we evaluate how novel species interactions, ocean acidification and warming affect shoaling dynamics, motor lateralization and boldness of range-extending tropical and co-shoaling temperate fishes under controlled laboratory conditions. Fishes were exposed to 1 of 12 treatments (combinations of three temperature levels, two pCO2  levels and two shoal type levels: mixed species or temperate only) for 38 days. Lateralization (a measure of asymmetric expression of cognitive function in group coordination and predator escape) of tropical and temperate species was right-side biased under present-day conditions, but side bias significantly diminished in tropical and temperate fishes under ocean acidification. Ocean acidification also decreased shoal cohesion irrespective of shoaling type, with mixed-species shoals showing significantly lower cohesion than temperate-only shoals irrespective of climate stressors. Tropical fish became bolder under ocean acidification (after 4 weeks), and temperate fish became bolder with increasing temperature, while ocean acidification dampened temperate fish boldness. Our findings highlight the direct effect of climate stressors on fish behaviour and the interplay with the indirect effects of novel species interactions. Because strong shoal cohesion and lateralization are key determinants of species fitness, their degradation under ocean warming and acidification could adversely affect species performance in novel assemblages in a future ocean, and might slow down tropical species range extensions.

Linear-Range Extension for Linear Variable Differential Transformer Using Hyperbolic Sine Function.

In this paper, a circuit technique to extend the measuring range of a linear variable differential transformer (LVDT) is proposed. The transfer characteristic of the LVDT contains the odd function form of the cubic polynomial. Therefore, the measuring range of a commercial LVDT is linear in a narrow range compared to its physical dimensions. The wide measuring range of the LVDT requires a large structure of the LVDT, which increases the scale and the cost of the measurement system. The measuring range of the LVDT can be linearly extended to the maximum of the stroke range using the proposed technique. The realization of the proposed technique is based on the use of the hyperbolic sine (sinh) function of the electronic circuit building block, named the class AB bipolar amplifier. The class AB bipolar amplifier can be obtained by the current feedback operational amplifier (CFOA). The circuit of the proposed technique requires two CFOAs and an operational transconductance amplifier (OTA) as the active devices and all devices used in the proposed technique to synthesize the sinh function are commercially available. The proposed technique exhibits an ability to compensate for the nonlinear characteristic of the LVDT without digital components. The proposed technique is attractive in terms of its simple circuit configuration, small size, and low cost. The linear range extension of the LVDT used in this paper is significantly increased with a maximum error of about 18.3 µm of 6.2 mm at the full stroke range or the full-scale percentage error of about 0.295%. The results indicate that the proposed technique provides excellent performance to extend the measuring range of the LVDT without modifying the LVDT structure.

Species on the move around the Australian coastline: A continental-scale review of climate-driven species redistribution in marine systems.

Climate-driven changes in the distribution of species are a pervasive and accelerating impact of climate change, and despite increasing research effort in this rapidly emerging field, much remains unknown or poorly understood. We lack a holistic understanding of patterns and processes at local, regional and global scales, with detailed explorations of range shifts in the southern hemisphere particularly under-represented. Australian waters encompass the world's third largest marine jurisdiction, extending from tropical to sub-Antarctic climate zones, and have waters warming at rates twice the global average in the north and two to four times in the south. Here, we report the results of a multi-taxon continent-wide review describing observed and predicted species redistribution around the Australian coastline, and highlight critical gaps in knowledge impeding our understanding of, and response to, these considerable changes. Since range shifts were first reported in the region in 2003, 198 species from nine Phyla have been documented shifting their distribution, 87.3% of which are shifting poleward. However, there is little standardization of methods or metrics reported in observed or predicted shifts, and both are hindered by a lack of baseline data. Our results demonstrate the importance of historical data sets and underwater visual surveys, and also highlight that approximately one-fifth of studies incorporated citizen science. These findings emphasize the important role the public has had, and can continue to play, in understanding the impact of climate change. Most documented shifts are of coastal fish species in sub-tropical and temperate systems, while tropical systems in general were poorly explored. Moreover, most distributional changes are only described at the poleward boundary, with few studies considering changes at the warmer, equatorward range limit. Through identifying knowledge gaps and research limitations, this review highlights future opportunities for strategic research effort to improve the representation of Australian marine species and systems in climate-impact research.

The experimental range extension of guppies (Poecilia reticulata) influences the metabolic activity of tropical streams.

The ecological consequences of biological range extensions reflect the interplay between the functional characteristics of the newly arrived species and their recipient ecosystems. Teasing apart the relative contribution of each component is difficult because most colonization events are studied retrospectively, i.e., after a species became established and its consequences apparent. We conducted a prospective experiment to study the ecosystem consequences of a consumer introduction, using whole-stream metabolism as our integrator of ecosystem activity. In four Trinidadian streams, we extended the range of a native fish, the guppy (Poecilia reticulata), by introducing it over barrier waterfalls that historically excluded it from these upper reaches. To assess the context dependence of these range extensions, we thinned the riparian forest canopy on two of these streams to increase benthic algal biomass and productivity. Guppy's range extension into upper stream reaches significantly impacted stream metabolism but the effects depended upon the specific stream into which they had been introduced. Generally, increases in guppy biomass caused an increase in gross primary production (GPP) and community respiration (CR). The effects guppies had on GPP were similar to those induced by increased light level and were larger in strength than the effects stream stage had on CR. These results, combined with results from prior experiments, contribute to our growing understanding of how consumers impact stream ecosystem function when they expand their range into novel habitats. Further study will reveal whether local adaptation, known to occur rapidly in these guppy populations, modifies the ecological consequences of this species introduction.

Range Extension of Mesophotic Kelps (Ochrophyta: Laminariales and Tilopteridales) in the Central North Atlantic: Opportunities for Marine Forest Research and Conservation.

Kelp was first recorded for the remote warm-temperate Azores archipelago (central North Atlantic) in 1971, when a few Laminaria specimens were collected on the Formigas Bank at depths beyond conventional SCUBA diving reach. A shortage of technical means and projects targeting mesophotic environments has since kept this offshore marine protected area as the single known kelp occurrence site. Here, we present new kelp records collected on previously unexplored mesophotic reefs using remote imaging systems, open- and closed-circuit SCUBA diving, and fisheries bycatch information. The new data extend the known distribution range of kelp in the Azores 350 km to the west and 25 km to the southwest, henceforth including several island shelves in the eastern and central Azores. In addition to the previously recorded Laminaria ochroleuca, kelp specimens with a morphology akin to Phyllariopsis brevipes subsp. brevipes are also reported. For the first time, seabed imagery is used to document the depth-wise diversity of the Azores kelp beds and their associated biota. Our findings emphasize the poor knowledge that persists in regard to Macaronesia's mesophotic environments located beyond conventional SCUBA diving limits. The new on-shelf kelp occurrences add conservation value to coastal areas and should facilitate island-based research. However, their greater proximity to land-based impacts and exposure to climate change also raise management needs.

First record of Gorgona guitarfish (Pseudobatos prahli) off the Baja California peninsula with updated key to the guitarfishes of the North Eastern Pacific.

The Gorgona guitarfish is a poorly documented ray found in the Eastern Pacific. It can be distinguished from its congeners due to its distinctive coloration and rostral cartilages. Here I document an extensive northern range expansion of almost 2000 km based on a juvenile specimen caught off the Baja California Peninsula. This specimen also represents the smallest documented individual of this species, along with the first quantitative morphometric data reported since the 1995 description. Additionally, an updated key to the guitarfishes of the North Eastern Pacific is included.

Heterotrimeric G-protein shuttling via Gip1 extends the dynamic range of eukaryotic chemotaxis.

Chemotactic eukaryote cells can sense chemical gradients over a wide range of concentrations via heterotrimeric G-protein signaling; however, the underlying wide-range sensing mechanisms are only partially understood. Here we report that a novel regulator of G proteins, G protein-interacting protein 1 (Gip1), is essential for extending the chemotactic range ofDictyosteliumcells. Genetic disruption of Gip1 caused severe defects in gradient sensing and directed cell migration at high but not low concentrations of chemoattractant. Also, Gip1 was found to bind and sequester G proteins in cytosolic pools. Receptor activation induced G-protein translocation to the plasma membrane from the cytosol in a Gip1-dependent manner, causing a biased redistribution of G protein on the membrane along a chemoattractant gradient. These findings suggest that Gip1 regulates G-protein shuttling between the cytosol and the membrane to ensure the availability and biased redistribution of G protein on the membrane for receptor-mediated chemotactic signaling. This mechanism offers an explanation for the wide-range sensing seen in eukaryotic chemotaxis.

Genetic and historical evidence of common sawsharks Pristiophorus cirratus in the waters of southern Queensland.

In 2011, a male pristiophorid was caught by a prawn trawler north east of Cape Moreton, Queensland, Australia. Molecular analyses confirmed the specimen to be the common sawshark Pristiophorus cirratus. Historical catch data indicate the occurrence of the species in the region but this is the first verified record of P. cirratus occurring in the waters of southern Queensland. Together, these records extend the recognised northern limit of P. cirratus by c. 500 km, which suggests that further investigation of its distribution is warranted.

Chemoattractant receptors activate, recruit and capture G proteins for wide range chemotaxis.

The wide range sensing of extracellular signals is a common feature of various sensory cells. Eukaryotic chemotactic cells driven by GPCRs and their cognate G proteins are one example. This system endows the cells directional motility towards their destination over long distances. There are several mechanisms to achieve the long dynamic range, including negative regulation of the receptors upon ligand interaction and spatial regulation of G proteins, as we found recently. However, these mechanisms are insufficient to explain the 105-fold range of chemotaxis seen in Dictyostelium. Here, we reveal that the receptor-mediated activation, recruitment, and capturing of G proteins mediate chemotactic signaling at the lower, middle and higher concentration ranges, respectively. These multiple mechanisms of G protein dynamics can successfully cover distinct ranges of ligand concentrations, resulting in seamless and broad chemotaxis. Furthermore, single-molecule imaging analysis showed that the activated Gα subunit forms an unconventional complex with the agonist-bound receptor. This complex formation of GPCR-Gα increased the membrane-binding time of individual Gα molecules and therefore resulted in the local accumulation of Gα. Our findings provide an additional chemotactic dynamic range mechanism in which multiple G protein dynamics positively contribute to the production of gradient information.

First record of the Pacific seahorse Hippocampus ingens in Guadalupe Island, Mexico.

This is the first record of the Pacific seahorse Hippocampus ingens at a northern oceanic island from the eastern Pacific Ocean. The photographic record of the juvenile female H. ingens was made in November 2015 during a cage diving trip at Guadalupe Island, Mexico. The presence of H. ingens in this area could be related to long distance dispersal mechanisms, as has been observed in other species of seahorses.

Range Extension and Behavioural Observations of the Recently Described Sheth's Dwarf Lemur (Cheirogaleus shethi).

Sheth's dwarf lemur, Cheirogaleus shethi, is a small, recently discovered nocturnal primate endemic to northern Madagascar. Unlike many other nocturnal lemurs, C. shethi lives sympatrically with morphologically similar species of its cryptic genus, making it difficult for biologists to determine its population density and distribution. Here, we present new data and observations of this species. During a series of rapid biodiversity assessments in the SAVA region of north-eastern Madagascar, we observed C. shethi in 10 different sites, 9 of which were not previously known to harbour C. shethi populations. More significantly, 2 of these sites, in Analamanara, were situated approximately 20 km south of the previously known southern extremity of this species' distribution. This represents a large increase in the previously limited geographic range of this species. Moreover, our relatively high encounter rates at these sites suggest that C. shethi population densities may be high. We also observed C. shethi in human-altered (e.g., vanilla plantations) and non-forest, savannah environments, suggesting that this species can tolerate disturbed habitats. Our findings therefore provide important additional information on the distribution of C. shethi populations and highlight the necessity of further study for the conservation of this species.

Novel biodiversity baselines outpace models of fish distribution in Arctic waters.

During a recent marine biological expedition to the Northeast Greenland shelf break (latitudes 74-77 °N), we made the first discovery of Atlantic cod (Gadus morhua), beaked redfish (Sebastes mentella) and capelin (Mallotus villosus). Our novel observations shift the distribution range of Atlantic cod >1000 km further north in East Greenland waters. In light of climate change, we discuss physical forcing and putative connections between the faunas of the Northeast Greenland shelf and the Barents Sea. We emphasise the importance of using real data in spread scenarios for understudied Arctic seas.

Is the threatened land crab Cardisoma guanhumi conquering human-dominated systems?

Land use changes are heralded as a major driver of biodiversity loss. However, recent findings show that cities, perhaps the most radical habitat transformation, sustain increasing numbers of threatened species. This emerging trend has been mostly chronicled for vertebrates from landlocked cities, although loss of biodiversity and rates or urbanization are higher in coastal marine systems. To advance our understanding on how threatened species may conquer human-dominated systems, we studied the threatened edible crab Cardisoma guanhumi and assessed how it is proliferating in croplands and urban systems at different spatial scales and whether populations show consequences of long-term exploitation. We gathered the data on crab populations covering the whole distribution range, including three countries reporting this as a threatened species. The abundance, distribution, and size structure of crab populations among different land uses at local scales were compared and published data for populations thriving in different habitats throughout their distribution range were compiled. We found that at local scale this species is able to thrive in natural and human-disturbed habitats, where food sources are heavily altered. At larger scales, the species showed no differences in abundance and size structure among natural and anthropogenic habitats. In areas near the southern distribution edge, crab populations were more abundant and composed of larger animals in urban areas and croplands than those in natural habitats, suggesting that human-disturbed systems are stepping stones to extend the geographic range. However, we found a long-term reduction in maximum body size, exacerbated by land use changes, that likely reflects exploitation regimes consistently targeting larger crabs. Despite its status as a threatened species, the long history of human exploitation combined with livestock farming practices may explain the proliferation of this crab in human-dominated systems, which emphasize the need to consider conservation in human-dominated systems.