Entrance Size Research Articles

Single-Molecule-Based, Label-Free Monitoring of Molecular Glue Efficacies for Promoting Protein-Protein Interactions Using YaxAB Nanopores.

Modulating protein-protein interactions (PPIs) is an attractive strategy in drug discovery. Molecular glues, bifunctional small-molecule drugs that promote PPIs, offer an approach to targeting traditionally undruggable targets. However, the efficient discovery of molecular glues has been hampered by the current limitations of conventional ensemble-averaging-based methods. In this study, we present a YaxAB nanopore for probing the efficacy of molecular glues in inducing PPIs. Using YaxAB nanopores, we demonstrate single-molecule-based, label-free monitoring of protein complex formation between mammalian target of rapamycin (mTOR) and FK506-binding proteins (FKBPs) triggered by the molecular glue, rapamycin. Owing to its wide entrance and adjustable pore size, in combination with potent electro-osmotic flow (EOF), a single funnel-shaped YaxAB nanopore enables the simultaneous detection and single-molecule-level quantification of multiprotein states, including single proteins, binary complexes, and ternary complexes induced by rapamycin. Notably, YaxAB nanopores could sensitively discriminate between the binary complexes or ternary complexes induced by rapamycin and its analogues, despite the subtle size differences of ∼122 or ∼116 Da, respectively. Taken together, our results provide proof-of-concept for single-molecule-based, label-free, and ultrasensitive screening and structure-activity relationship (SAR) analysis of molecular glues, which will contribute to low-cost, highly efficient discovery, and rational design of bifunctional modality of drugs, such as molecular glues.

Binding kinetics of quaternary ammonium ions in Kcv potassium channels.

Kcv channels from plant viruses represent the autonomous pore module of potassium channels, devoid of any regulatory domains. These small proteins show very reproducible single-channel behavior in planar lipid bilayers. Thus, they are an optimum system for the study of the biophysics of ion transport and gating. Structural models based on homology modeling have been used successfully, but experimental structural data are currently not available. Here we determine the size of the cytosolic pore entrance by studying the blocker kinetics. Blocker binding and dissociation rate constants ranging from 0.01 to 1000 ms-1 were determined for different quaternary ammonium ions. We found that the cytosolic pore entrance of KcvNTS must be at least 11 Å wide. The results further indicate that the residues controlling a cytosolic gate in one of the Kcv isoforms influence blocker binding/dissociation as well as a second gate even when the cytosolic gate is in the open state. The voltage dependence of the rate constant of blocker release is used to test, which blockers bind to the same binding site.

Cave-roosting specialisation of an oceanic island endemic microbat elevates extinction risks as caves face multiple threats

Bats (Chiroptera) constitute one-fifth of the global mammalian diversity, with over 1,450 species. Yet, 16.5 % of them are threatened with extinction, a situation exacerbated on islands, underscoring an urgent need for conservation efforts there. However, effective conservation action can only be as sound as the understanding of the basic ecology of such insular species. Mauritius harbours one endemic Endangered cave-roosting insectivorous bat, in recent decline, whose ecology is poorly known, hampering its conservation. We used Mormopterus acetabulosus as a model species to inform insectivorous island bat conservation in highly transformed habitats. We compared the species’ historical and current known roost distribution and sizes and estimated any change in its Area of Occupancy (AOO) and Extent of Occurrence (EOO) using GeoCAT. We also compiled the physical characteristics, environmental and anthropogenic variables of caves that are occupied and unoccupied by the bats to identify potential factors influencing roost occupancy. We found roosts in 17 of the recorded 130 lava cave tunnels, up from the nine previously recorded, including 11 permanent and six seasonal roosts, mostly (∼71 %) on privately owned land. Compared to the last surveys in 2017, the EOO remained stable at 818.9 km2, while the AOO increased by 33.3 %. This expansion may reflect previously undetected roosts or recent colonisation events or both. Cave dimensions in terms of entrance size and height as well as the number of chambers, relative humidity and distance to water best explained roost occupancy by M. acetabulosus. Caves with larger entrances may be preferred for roosting as this characteristic eases manoeuvrability and predator avoidance, and larger caves may be preferred for enhanced microclimatic stability. Occupied and unoccupied caves were found to differ in terms of physical characteristics, although cave microclimate did not vary notably. Based on their characteristics and their potential contributions to increasing the species’ EOO and AOO, six currently unoccupied caves were identified as priority sites for future conservation efforts. Legal protection of all caves, regardless of current bat occupancy is necessary to mitigate extinction risks and preserve their associated ecological functions.

Homogeneous removal of heterogeneous CFRP composite via aluminum/polyimide laminate assisted femtosecond laser processing

Carbon fiber reinforced polymer (CFRP) composed of carbon fiber and polymer matrix has been used in extensive applications due to its light weight and superior strength. However, the distinct difference in physicochemical properties between two constituents poses a significant challenge for laser homogeneous processing of heterogeneous CFRP. Herein, an aluminum/polyimide laminate is introduced onto CFRP as an assisting layer during femtosecond laser processing, which prevents CFRP from direct energy deposition of low-energy edge of the Gaussian laser. Moreover, a synergetic mechanism of horizontal heat conduction of aluminum foil and vertical heat insulation of polyimide film is proposed and confirmed through temperature measurements and simulation calculations. The heat is dissipated through the aluminum foil and obstructed by the polyimide film, alleviating the detrimental heat transfer and accumulation on CFRP. Therefore, it significantly inhibits thermal damage and entrance size expansion. Compared with traditional femtosecond laser direct processing, the maximum reduction ratio of HAZ and taper are up to 98% and 83%, respectively. High-quality CFRP homogeneous processing with an ultra-low HAZ (0.7 μm), minimal taper (0.07°) and intact smooth sidewalls can be achieved. The method shows great potential to dramatically improve processing quality and broaden applications of heterogeneous composites.

Partial Water Intrusion and Extrusion in Hydrophobic Nanopores for Thermomechanical Energy Dissipation.

Forced wetting (intrusion) and spontaneous dewetting (extrusion) of hydrophobic/lyophobic nanoporous materials by water/nonwetting liquid are of great importance for a broad span of technological and natural systems such as shock-absorbers, molecular springs, separation, chromatography, ion channels, nanofluidics, and many more. In most of these cases, the process of intrusion-extrusion is not complete due to the stochastic nature of external stimuli under realistic operational conditions. However, understanding of these partial processes is limited, as most of the works are focused on an idealized complete intrusion-extrusion cycle. In this work, we show an experimental system operating under partial intrusion/extrusion conditions and present a simple model that captures its main features. We rationalize these operational conditions in terms of the pore entrance and cavity size distributions of the material, which control the range of intrusion/extrusion pressures.

Jet Electroforming of High-Aspect-Ratio Microcomponents by Periodically Lifting a Necked-Entrance Through-Mask.

High-aspect-ratio micro- and mesoscale metallic components (HAR-MMMCs) can play some unique roles in quite a few application fields, but their cost-efficient fabrication is significantly difficult to accomplish. To address this issue, this study proposes a necked-entrance through-mask (NTM) periodically lifting electroforming technology with an impinging jet electrolyte supply. The effects of the size of the necked entrance of the through-mask and the jet speed of the electrolyte on electrodeposition behaviors, including the thickness distribution of the growing top surface, deposition defect formation, geometrical accuracy, and electrodeposition rate, are investigated numerically and experimentally. Ensuring an appropriate size of the necked entrance can effectively improve the uniformity of deposition thickness, while higher electrolyte flow velocities help enhance the density of the components under higher current densities, reducing the formation of deposition defects. It was shown that several precision HAR-MMMCs with an AR of 3.65 and a surface roughness (Ra) of down to 36 nm can be achieved simultaneously with a relatively high deposition rate of 3.6 μm/min and thickness variation as low as 1.4%. Due to the high current density and excellent mass transfer effects in the electroforming conditions, the successful electroforming of components with a Vickers microhardness of up to 520.5 HV was achieved. Mesoscale precision columns with circular and Y-shaped cross-sections were fabricated by using this modified through-mask movable electroforming process. The proposed NTM periodic lifting electroforming method is promisingly advantageous in fabricating precision HAR-MMMCs cost-efficiently.

Functional convergence underground? The scale‐dependency of community assembly processes in European cave spiders

AbstractAimQuantifying the relative contribution of environmental filtering versus limiting similarity in shaping communities is challenging because these processes often act simultaneously and their effect is scale‐dependent. Focusing on caves, island‐like natural laboratories with limited environmental variability and species diversity, we tested: (i) the relative contribution of environmental filtering and limiting similarity in determining community assembly in caves; (ii) how the relative contribution of these driving forces changes along environmental gradients.LocationEurope.Time periodPresent.Major taxa studiedSubterranean spiders.MethodsWe used data on distribution and traits for European cave spiders (n = 475 communities). We estimated the trait space of each community using probabilistic hypervolumes, and obtained estimations of functional richness independent of the species richness of each community via null modelling. We model functional diversity change along environmental gradients using generalized dissimilarity modelling.ResultsSixty‐three percent of subterranean spider communities exhibited a prevalence of trait underdispersion. However, most communities displayed trait dispersion that did not depart significantly from random, suggesting that environmental filtering and limiting similarity were both exerting equally weak or strong, yet opposing influences. Overdispersed communities were primarily concentrated in southern latitudes, particularly in the Dinaric karst, where there is greater subterranean habitat availability. Pairwise comparisons of functional richness across caves revealed these effects to be strongly scale‐dependent, largely varying across gradients of cave development, elevation, precipitation, entrance size and annual temperature range. Conversely, geographical distance weakly affected trait composition, suggesting convergence in traits among communities that are far apart.Main conclusionsEven systems with stringent environmental conditions maintain the potential for trait differentiation, especially in areas of greater habitat availability. Yet, the relative influence of environmental filtering and limiting similarity change with scale, along clear environmental gradients. The interplay of these processes may explain the assembly of species‐poor subterranean communities displaying high functional specialization.

FEATURES OF THE APPLICATION OF A MAGNET FOR THE SURGICAL TREATMENT OF THE FIRE FRAGMENT WOUNDS OF THE THIGH AND BUTTOCKS. CLINICAL CASE

Introduction. Before the start of hostilities in Ukraine, the use of surgical magnetic instruments for the removal of ferromagnetic foreign bodies in everyday surgical practice was quite limited. The use of magnetic instruments provides, first of all, the possibility of control and safety of inflicting additional injuries during surgical operations. Materials and methods. The actual clinical observation and the complexity of the case of using a surgical magnet during the removal of a metal fragment due to a gunshot wound to the hip and buttock are demonstrated. Results. The primary surgical treatment of an open gunshot wound of the thigh and buttock with the presence of a foreign body on the radiograph of the pelvis in the direct and lateral projection near the lesser trochanter of the femur 5 hours after the injury with the use of surgical magnetic and classical surgical instruments (Billroth clamp) was performed on a 50-year-old patient. The small size of the wound entrance limited the ability to maneuver the instrument in the wound. And the deep immersion of the fragment in the soft tissues of the buttock made visualization and its palpation impossible. A significant risk of damage to large vessels and nerves during maneuvering is determined by the exact location of the fragment, the density of the metal, and the difficulty of its capture and fixation with a surgical instrument, due to the fragment sliding and catching on the femur. Conclusions. In complex cases, classic surgical instruments can be used along with magnetic instruments. Preoperative diagnosis of a foreign body should include X-ray examination if it is impossible to visualize and palpate the fragments. The use of surgical magnetic instruments expands the possibility of performing primary surgical treatment of wounds, reduces the traumatic nature of the operation and the terms of inpatient treatment and rehabilitation.

Critical interpretation and analysis to correlate the canopy height to collector diameter ratio for optimized design of solar chimney power plants

The collector's periphery height determines the entrance size to the solar chimney power plant. There is inconsistency in the published experimental and numerical results on the optimum collector inlet height for different collector diameters. This paper aims to analyze the available data to identify the best collector inlet height-to-diameter ratio and to introduce a design guide for an optimized performance of solar chimney power plants. The experimental data reported in previous works have been clustered and manipulated to produce a comparative argument on the collector inlet height-to-diameter. In addition, a numerical model is developed to support the literature conclusions and to produce further data to decide the optimum collector inlet height-to-diameter ratio. For a 6.6-m collector diameter, four different inlets have been investigated, namely, 0.05, 0.1, 0.15, and 0.2 m. The best performance in terms of air velocity and temperature rise is obtained with the 0.05-m inlet height, where it shows an improvement of up to 35.35% compared to the larger inlet heights. The lower collector inlet height allows a more effective heat transfer from the ground and the collector to the air. It is concluded that the optimum collector inlet height-to-diameter design ratio for solar chimneys with collector diameters larger than 3 m is 0.0075±0.0005. For small-scale solar chimney models with less than 3 m collector diameter, the best collector inlet height-to-diameter ratio ranges between 0.015 and 0.03.

Ancient, veteran and other listed trees as nest sites for wild-living honey bee, Apis mellifera, colonies

Wild-living honey bee (Apis mellifera) colonies naturally nest in old cavity-bearing trees throughout their range, but this important nesting habitat is in global decline. Here we determine the use of ancient, veteran and other listed trees as nest sites by wild-living honey bee colonies in Britain and investigate the effect of tree size, genus and management on occupancy. Over 1,000 trees of special interest (TSIs) were surveyed in southeast England using the Ancient Tree Inventory (ATI) of the Woodland Trust, a charity that protects and promotes trees in Britain. 2% of all TSIs and 4.4% of TSIs with cavities were occupied by wild-living honey bee colonies (n = 21). Occupancy positively correlated with tree diameter, which is surprising given that the overall sample already had a large mean diameter of 1.3 m. Wild-living colonies occupied sweet chestnut (Castanea sativa) more frequently than expected (7% versus 2% overall), probably due to their large mean diameter (1.6 m) and proportion of trees with cavities (73%). Heights of occupied tree cavities (including non-ATI trees) ranged from 0 to 18.2 m with a median of 6.8 m, entrance size ranged from 2.2 to 322 cm2 with a median of 33.8 cm2 and entrance orientation was not significantly different from random.

Enhanced activity of Candida antarctica lipase B in cholinium aminoate ionic liquids: a combined experimental and computational analysis

As a class of ionic liquids with higher biocompatibility, cholinium aminoates ([Cho][AA]) hold potential as solvation media for enzymatic bioprocessing. Herein, solvation effect of [Cho][AA] on structural stability and enzymatic activity of Candida antarctica lipase B (CALB) was evaluated using experimental and computational approaches. Influence of [Cho][AA] on CALB stability was investigated using amino acid anions ([AA]-) with varying hydrophobicity levels. Choline phenylalaninate ([Cho][Phe]) resulted in 109.1% and 110.4% of relative CALB activity to buffer medium at 25 °C and 50 °C, respectively. Simulation results revealed the improvement of CALB’s enzymatic activities by [AA]- with a strong hydrophobic character. Shielding of CALB from water molecules by [AA]- was observed. The level of CALB activity was governed by accumulation level of [AA]- at CALB’s first hydration layer. The stronger interaction between His224 and Asp187 was postulated to be driven by [Cho][AA], resulting in the activity enhancement of CALB. The slight improvement of CALB activity in 0.05 M [Cho][Phe] at 50 °C could be due to the larger size of entrance to the catalytic site and the stronger interaction between the catalytic residues. The promising effect of [Cho][Phe] on CALB activation may stimulate research efforts in designing a ‘fully green’ bioreaction for various industrial applications. Communicated by Ramaswamy H. Sarma

Effects of morphological characteristics of patent foramen ovale by transesophageal echocardiography on minimalist transcatheter closure in southern China.

Transcatheter closure has become one of the main treatment methods for patent foramen ovale (PFO). However, the population in southern China is generally thin and the size of PFO is small, so the application of minimalist surgery is challenging. This study aimed to analyze the morphological characteristics of PFOs in southern China by transesophageal echocardiography (TEE), and to explore the influence on minimalist transcatheter closure. About 110 patients with PFO closure in our hospital were selected. All cases were examined by TEE including the PFO size, length, septum secundum thickness, color characteristic and surrounding structures, and morphologically classified. During the operation, the procedure time, number of times for the guidewire attempting to pass the interatrial septum and the success rate of simply using J guidewire to cross the interatrial septum were recorded. About 110 cases of PFO were classified into two categories and four subtypes, including 55 cases with Uniform Channel Type (UCT, 50.0%), 16 cases with Irregular Channel Type (ICT, 14.6%), 15 cases with Right Funnel Type (RFT, 13.6%), and 24 cases with Left Funnel Type (LFT, 21.8%). According to the complexity of the procedure, they were divided into simple procedure (n=73) and complex procedure (n=37). Multivariate logistic regression showed that the anatomical types of PFO, the tunnel entrance size, and the tunnel entrance size <2mm were independent factors affecting the complexity of procedure [OR=2.819, 95% CI (1.124, 7.066), p=.027; OR=.027, 95% CI (.004, .208), p=.001; OR=4.715, 95% CI (1.028, 21.619), p=.046]. With ICT and LFT groups, the procedure duration was relatively long (p<.001), number of times for the guidewire attempting to pass the interatrial septum was significantly increased (p<.001), and the success rate of simply using J guidewire to cross the interatrial septum was relatively low (p<.001). The PFO size in southern China was relatively small and characterized by large tunnel tension. It was concluded that TEE could clearly show the morphological characteristics of PFO, which could provide guidance for making more reasonable surgical plans in clinical practice, shorten the procedure time and improve the success rate of PFO closure.

Does size matter? Bat diversity and the use of rock shelters in Brazil

A positive correlation between cave size and bat diversity has been recorded by some authors for different cave areas in South America. We analyzed published and otherwise available data from three Brazilian karst areas and phytogeography domains, including NE and SE Atlantic Forest and Cerrado (savannah-like vegetation), encompassing a wide range of cave sizes. We found no such correlation, as expected in view of previous observations by researchers and speleologists. We discuss the ecological implications of different ways to measure bat diversity, i.e. the accumulative number of species (sequential use of caves) vs. the number of species at a given occasion (species in actual cohabitation) vs. bat abundance (numbers of individuals), as well as speleological topics related to the concept of caves (based on an anthropomorphic definition, not applicable to other species), the problems of estimating topographic variables such as cave area and volume, and the value of including cave temperatures in the analyses. Multiple interacting variables may influence the composition of cave bat communities and bat species richness and abundance. The most important ones would be the density of caves in a given area (related to lithology – calcareous vs. siliciclastic caves), regional climates, and degree of preservation of epigean habitat. Cave morphology, number and size of entrances, and presence of water bodies, as well as interactions with other species, must also be considered. In conclusion, as a general statement for tropical and subtropical bats, cave size (in the human sense) by itself does not matter, except perhaps for one-off situations. Finally, a brief overview of the diversity of cave bats in Brazil is presented.

Simple pot modification improves catch efficiency and species composition in a tropical estuary mud crab (Scylla serrata) fishery

Pots are widely used fishing gear type for targeting different crustacean and fish species. Pot entrance size and design are among the most important technical parameters that influence the catch efficiency of certain species. An optimal pot entrance design should allow an efficient entry for the target species while preventing subsequent escape. The tropical estuary pot fishery targeting mud crab (Scylla serrata) in Vembanad Lake, India, employs rectangular pots with rectangular-shaped entrances. Low catch rates for target species and high bycatch rates are observed in this fishery. This study was carried out to investigate if a simple pot modification by extending the entrance of the traditional pots, can improve the catch efficiency of mud crab. Further, we estimated and compared the catch composition in this small-scale fishery using the traditional and modified entrance pots. The results showed that the catch efficiency for all sizes of mud crab is on average more than six times higher with the modified entrance pots compared to the traditional pots (622% (CI: 344–1867%)). However, significant quantities of juvenile crabs are caught in modified pots. Further, the bycatch ratio was significantly reduced for modified compared to the standard entrance pots in this fishery. These results show that such pot modifications have potential to significantly improve the catches in mud crab pot fisheries without increase in capture of bycatch species. However, additional mechanisms for excluding undersized crabs from pot catches should be investigated.

Structural Analysis of Interactions between Epidermal Growth Factor Receptor (EGFR) Mutants and Their Inhibitors

People’s lives and health are gravely threatened by non-small-cell lung cancer (NSCLC). Mutations in epidermal growth factor receptor (EGFR), a transmembrane receptor tyrosine kinase, are considered one of the causes of NSCLC. Tyrosine kinase inhibitors (TKIs) are typically used to treat patients with EGFR mutations. In this study, Gefitinib, a member of the first generation of TKIs, was used to treat an EGFR single-point mutation (single mutant, SM). Patients harboring additional T790M mutations in the kinase domain of the EGFR were resistant to Gefitinib. Then, the L858R/T790M double mutation (double mutant, DM) was treated with the second generation of TKIs, such as Afatinib. Here, we constructed four computational models to uncover the structural basis between EGFR mutants (SM and DM) and corresponding inhibitors (Gefitinib and Afatinib). The binding energy in the G-SM (representing Gefitinib in complex with SM) system was larger than that in the G-DM (Representing Gefitinib in complex with DM) system. Gefitinib’s affinity with L792 and M793 was drastically reduced by the longer side chain of M790 in the G-DM system, which pushed Gefitinib outside of the pocket. Additionally, the A-DM system’s binding energy was higher than the G-DM system’s. Afatinib, unlike Gefitinib, induced the P-loop region to move downwards to decrease the pocket entrance size to accommodate Afatinib properly and stably in the A-DM (Afatinib in complex with DM) system. These results uncover the details of interactions between EGFR and its inhibitors and shed light on the design of new tyrosine kinase inhibitors.

A case report of an Eurasian jay (Garrulus glandarius) attacking an incubating adult and depredating the eggs of the Japanese tit (Parus minor).

In May 2021, we opportunistically observed one Eurasian jay (Garrulus glandarius) attacking an adult incubating Japanese tit (Parus minor) and depredating nine tit eggs at a nest box where a woodpecker had greatly enlarged the entrance. After the predation event, the Japanese tits abandoned the nest. We recommend that when using artificial nest boxes to protect hole-nesting birds, the appropriate entrance size should be proportional to the body size of the target species. This observation gives us a better understanding of the potential predators of secondary hole-nesting birds.

Analysis of the alveolar shape in 3-D.

Mechanical forces affect the alveolar shape, depending on location and tissue composition, and vary during the respiratory cycle. This study performs alveolar morphomics in different lobes of human lungs using models generated from three-dimensional (3-D) micro-computed tomography (microCT) images. Cylindrical tissue samples (1.6 cm × 2 cm) were extracted from two nontransplantable donor lungs (one ex-smoker and one smoker, 3 samples per subject) that were air-inflated and frozen solid in liquid nitrogen vapor. Samples were scanned with microCT (11 µm/voxel). Within representative cubic regions of interest (5.5 mm edge length), alveoli were segmented to produce corresponding 3-D models from which quantitative data were obtained. The surface of segmented alveoli (n_alv_total = 23,587) was divided into individual planar surfaces (facets) and angles between facet normals were calculated. Moreover, the number of neighboring alveoli was estimated for every alveolus. In this study, we examined intraindividual differences in alveolar morphology, which were reproducible in the lungs of two subjects. The main aspects are higher mean alveolar volumes (v_alv: 6.64 × 106 and 6.63 × 106 µm3 vs. 5.78 × 106 and 6.29 × 106 µm3) and surface sizes (s_alv: 0.19 and 0.18 mm2 vs. 0.17 mm2 in both lower lobes) in both upper lung lobes compared with the lower lobes. An increasing number of facets (f_alv) from top to bottom (12 and 14 in the upper lobes; 14 and 15 in the lower lobes), as well as a decreasing number of alveolar neighbors (nei_alv: 9 and 8 in the upper lobes; 8 and 7 in the lower lobes) from the upper lobes to the lower lobes were observed. We could observe an increasing ratio of alveolar entrance size to the surface size of the alveoli from top to bottom (S_ratio_alv: 0.71 and 0.64 in the upper lobes, 0.73 and 0.70 in the lower lobes). The angles between facet normals (ang_alv) were larger in the upper lobes (67.72° and 62.44°) of both lungs than in the lower lobes (66.19° and 61.30°). By using this new approach of analyzing alveolar 3-D data, which enables the estimation of facet, neighbor, and shape characteristics, we aimed to establish the baseline measures for in-depth studies of mechanical conditions and morphology.

Asistiendo a la reintroducción de vizcachas (Lagostomus maximus): ¿Cómo aumentar el área de pastoreo seguro?

The reintroduction of fossorial mammals could be limited by the availability of satellite burrows that provide refuge from predators while foraging away from their permanent burrows, and by availability of short grasses. In order to generate information to assist in the reintroduction of vizcachas (Lagostomus maximus), we asked: 1) what type of satellite burrow do they accept based on burrow complexity, entrance size and distance from permanent burrows?, and 2) how did the provision of burrows and mowing affect their foraging range? We carried out the study in the Sierras of Cordoba, Argentina, with 13 vizcachas transferred to two adaptation pens equipped with permanent burrows. We mowed part of the vegetation around the pens and we dug 14 satellite burrows of two types: simple with only a tunnel, and complex with a tunnel and underground chamber. Burrows were situated between 1 and 16 m from the pens. For six months we evaluated satellite burrow occupancy. We also counted feces, estimated bare soil, and height of the vegetation in 15-m-long transects originating in the entrances of highly used burrows, which were distributed in two sectors. Occupancy was 2 and 67% for simple and complex satellite burrows, respectively, and was negatively related to burrow entrance size. There was no relationship between burrow occupancy and distance to adaptation pens. Transect sampling showed that 91% of the pellets were within 4 m of the pens or satellite burrows, and that they preferred cut to uncut grass. We conclude that building complex satellite burrows and mowing vegetation will increase secure foraging range for translocated vizcachas.

Correlated expression of phenotypic and extended phenotypic traits across stingless bee species: worker eye morphology, foraging behaviour, and nest entrance architecture

Stingless bees are the most species-rich group of eusocial bees and show great diversity in behaviour, ecology, nest architecture, colony size, and worker morphology. How this variation relates to varying selection pressures and constraints is not well understood. Variation can be caused by selection acting on behavioural or morphological traits, both alone and in correlation across traits. Here we tested whether behavioural and morphological traits important for foraging and defence are linked to nest-entrance architecture, an extended phenotype relevant to both foraging and nest defence. Using 23 species we investigated whether eye size, nest entrance size, landing behaviour and foraging method show cross-species correlations. A phylogenetically-controlled comparative analysis revealed that species with relatively smaller eyes build relatively larger entrances, which in turn are associated with faster landing approaches and fewer landing errors by foragers, both of which could reduce predation risk. Concerning foraging, mass-recruiting species have c. 10-times larger entrance holes than species with a solitary foraging strategy. Larger entrances could help species with mass recruitment to rapidly increase forager traffic or mount a strong defensive response when under attack. Our results show that studying correlations among different traits helps understand phenotypic diversity in species rich groups.

Engineering the Entrance of a Flavonoid Glycosyltransferase Promotes the Glycosylation of Etoposide Aglycone.

Enzyme entrances, which function as the first molecular filters, influence substrate selectivity and enzymatic activity. Because of low binding affinities, engineering enzyme entrances that recognize non-natural substrates is a major challenge for artificial biocatalyst design. Here, the entrance of flavonoid glycosyltransferase UGT78D2 was engineered to promote the recognition of the aglycone of etoposide, a chemotherapeutic agent. We found that Q258, S446, R444, and R450, the key residues surrounding the substrate entrance, specifically guide the flux of etoposide aglycone, which has a high steric hindrance, into the active site; this activity was inferred to be determined by the entrance size and hydrophobic and electrostatic interactions. Engineering the coordination of Q258 and S446 to increase the entrance size and hydrophobic interaction between UGT78D2 and etoposide aglycone increased the affinity by 10.10-fold and the conversion by 10%. The entrance-engineering strategy applied in this study can improve the design of artificial biocatalysts.