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International audience; Arbuscular mycorrhizal (AM) fungi play a key role in determining ecosystem functionality. Understanding how diversity in the fungal community affects plant productivity is therefore an important question in ecology. Current research has focused on understanding the role of functional complementarity in the fungal community when the host plant faces multiple stress factors. Fewer studies, however, have investigated how variation in traits affecting nutrient exchange can impact the plant growth dynamics, even in the absence of environmental stressors. Combining experimental data and a mathematical model based on ordinary differential equations, we investigate the role played by carbon sink strength on plant productivity. We simulate and measure plant growth over time when the plant is associated with two fungal isolates with different carbon sink strength, and when the plant is in pairwise association with each of the isolates alone. Overall, our theoretical as well as our experimental results show that co-inoculation with fungi with different carbon sink strength can induce positive non-additive effects (or synergistic effects) in plant productivity. Fungi with high carbon sink strength are able to quickly establish a fungal community and increase the nutrient supply to the plant, with a consequent positive impact on plant growth rate. On the other side, fungi with low carbon sink strength inflict lower carbon costs to the host plant, and support maximal plant productivity once plant biomass is large. As AM fungi are widely used as organic fertilizers worldwide, our findings have important implications for restoration ecology and agricultural management.

Background: This study was conducted to examine the development of the embryo during incubation and the composition, amount and consumption of the egg nutrients among Chukars (Alectoris chukar). Methods: A total of 1210 eggs were carefully separated into their components (albumen, yolk, shell, amniotic-allantoic fluid and embryo) on day 0 (fresh), in the first (day 7), second (day 14) and third (day 21) weeks of incubation and on the hatching date. The moisture, crude protein, crude fat, carbohydrate, crude ash and energy level were determined in egg components. Result: The albumen, yolk, shell, fluid and embryo rates were calculated to be 53.62, 34.84, 11.53, 0.0 and 0.0% in fresh egg, 16.74, 33.49, 16.22, 31.76 and 2.06% in the first week of incubation, 15.65, 28.32, 15.58, 23.35 and 17.10% in the second week of incubation and 0.0, 23.33, 19.38, 0.0 and 57.29% in the third week of incubation, respectively. The hatching weight of the chick was 16.16 g. The nutrients of the yolk, albumen, fluid and shell proportionally varied significantly in different periods of incubation. According to the nutrient changes calculated based on the weight differences of egg components, carbohydrates were mostly used for nutrients during incubation. It was found that even though the nutrients in all the egg components were used in the different periods of incubation, egg yolk was an important source for the embryo throughout the incubation period.

Bone defects caused by trauma and surgery are common clinical problems encountered by orthopedic surgeons. Thus, a hard-textured, natural-like biomaterial that enables encapsulated cells to obtain the much-needed biophysical stimulation and produce functional bone tissue is needed. Incorporating nanomaterials into cell-laden hydrogels is a straightforward tactic for producing tissue engineering structures that integrate perfectly with the body and for tailoring the material characteristics of hydrogels without hindering nutrient exchange with the surroundings. In this review, recent developments in inorganic nanocomposite hydrogels for bone tissue engineering that are of vital importance but have not yet been comprehensively reviewed are summarized.

Older melanoma patients (>50 years old) have poorer prognoses and response rates to targeted therapy compared to young patients (

Summary Associations formed between plants and arbuscular mycorrhizal (AM) fungi are characterized by the bi-directional exchange of fungal-acquired soil nutrients for plant-fixed organic carbon compounds. Mycorrhizal-acquired nutrient assimilation by plants may be symmetrically linked to carbon (C) transfer from plant to fungus or governed by sink-source dynamics. Abiotic factors, including atmospheric CO2 concentration ([CO2]), can affect the relative cost of resources traded between mutualists, thereby influencing symbiotic function. Whether biotic factors, such as insect herbivores that represent external sinks for plant C, impact mycorrhizal function remains unstudied. By supplying 33P to an AM fungus (Rhizophagus irregularis) and 14CO2 to wheat, we tested the impact of increasing C sink strength (i.e., aphid herbivory) and increasing C source strength (i.e., elevated [CO2]) on resource exchange between mycorrhizal symbionts. Allocation of plant C to the AM fungus decreased dramatically following exposure to the bird cherry-oat aphid (Rhopalosiphum padi), with high [CO2] failing to alleviate the aphid-induced decline in plant C allocated to the AM fungus. Mycorrhizal-mediated uptake of 33P by plants was maintained regardless of aphid presence or elevated [CO2], meaning insect herbivory drove asymmetry in carbon for nutrient exchange between symbionts. Here, we provide direct evidence that external biotic C sinks can limit plant C allocation to an AM fungus without hindering mycorrhizal-acquired nutrient uptake. Our findings highlight the context dependency of resource exchange between plants and AM fungi and suggest biotic factors—individually and in combination with abiotic factors—should be considered as powerful regulators of symbiotic function., Graphical Abstract, Highlights • We tested how aphid herbivory and increasing CO2 affects wheat mycorrhizal function • Aphids reduced wheat C supply to mycorrhizal fungi. High CO2 had no effect. • Transfer of fungal 33P to plant was maintained regardless of aphids or high CO2 • Mycorrhizal function is context dependent, affected by biotic and abiotic factors, Little is known about how mycorrhizal function is affected by insect herbivory and environment. Charters et al. show aphids reduce plant C allocation to mycorrhizas, although fungal P transfer to plants is maintained, suggesting high context dependency where resource exchange between symbionts is influenced by interacting biotic and abiotic factors.

Little is known about the establishment of symbioses. A new study finds that two independent protist-algae symbioses utilize convergent patterns of nutrient exchange, suggesting that certain complementary host and symbiont traits can increase the likelihood of establishing beneficial symbiotic interactions.

Low back pain is the leading cause of disability worldwide and in many patients the source of pain can be attributed to pathological changes within the intervertebral disc (IVD). As present treatment options fail to address the underlying biological problem, novel therapies are currently subject to intense research. The physiologic IVD microenvironment features a highly complex interaction of biochemical and mechanical factors influencing cell metabolism and extracellular matrix turnover and is therefore difficult to simulate for research purposes on IVD pathology. The first whole organ culture models were not able to sufficiently replicate human in vivo conditions as mechanical loading, the predominant way of IVD nutrient supply and waste exchange, remained disregarded. To mimic the unique IVD niche more realistically, whole organ culture bioreactors have been developed, allowing for dynamic loading of IVDs and nutrient exchange. Recent advancements on bioreactor systems have facilitated whole organ culture of various IVDs for extended periods. IVD organ culture bioreactors have the potential to bridge the gap between in vitro and in vivo systems and thus may give valuable insights on IVD pathology and/or potential novel treatment approaches if the respective model is adjusted according to a well-defined research question. In this review, we outline the potential of currently utilized IVD bioreactor systems and present suggestions for further developments to more reliably investigate IVD biology and novel treatment approaches.

Küresel ısınmayla birlikte sukaynaklarında ciddi azalmalar meydana gelmiştir. Küresel ısınmanın sonucuortaya çıkan kuraklık stresi üretimi büyük oranda etkilemiştir. Kuraklık stresiverim ve kaliteyi azaltmasının yanı sıra üreticilere de maddi sıkıntılaryaşatmaktadır. Kuraklık stresinin etkisine bağlı olarak oluşan hasarların enaza indirgenmesi amacıyla alınacak önlemlerden bir tanesi de kuraklığa tolerantçeşitlerin belirlenmesidir. Bu nedenle mevcut çalışmada kuraklığa toleransgösteren domates genotiplerinin belirlenmesi amaçlanmıştır. Çalışmada üç adethibrit, üç adet standart ve üç adet mahalli domates çeşidi kullanılmıştır. Domates tohumları 1:1 oranında torf + perlitkarışımı içeren 2 litrelik saksılara ekilmiştir. Gerçek yapraklar oluştuktansonra fideler, Hoagland besin çözeltisiyle sulama yapılmıştır. Sulama, kontrolbitkilerinde çalışma bitirilinceye kadar devam ederken, kuraklık uygulananbitkilerde ise fide döneminde sulama tamamen kesilmiştir. Sulama kesildikten 12gün sonra domates genotiplerindekatalaz(CAT), süperoksitdismutaz (SOD), askorbatperoksidaz (APX), potasyum (K),kalsiyum (Ca) ve magnezyum (Mg) içeriklerindekideğişimlerincelenmiştir. Kuraklık stresine tolerant veduyarlı domates genotiplerinin belirlenmesinde incelenen bu parametrelerdebariz farklar oluştuğu gözlemlenmiştir., Along with global warming, seriousreductions occurred in water resources. The drought stress resulting fromglobal warming has greatly affected production. As well as reducing yield andquality in production, drought also reduces farmer's income. One of themeasures to be taken in order to minimize the damage caused by the effect ofdrought stress is to determine the tolerance of the genotypes to drought.Accordingly, three hybrids varieties, three standards varieties and threelandraces of tomatoes were used in the present study. Tomato seeds were sown ina 2 liters-pot that contains 1:1 mixture of peat + perlite. After the trueleaves emerged, the seedlings were irrigated with the Hoagland nutrientsolution. While irrigation was carried on the control plants until the end ofthe application, irrigation was completely terminated during the seedlingperiod in the plants that are exposed to drought. 12 days after the irrigationcut in tomato genotypes, the changes in the level of catalase (CAT), superoxidedismutase (SOD), ascorbate peroxidase (APX), potassium (K), calcium (Ca) and magnesium were examined. It was observed that there were significantdifferences in these parameters examined for the determination of tomatogenotypes that are tolerant and sensitive to drought stress.

Coastal shelf seas are zones of intense nutrient cycling, where a strong coupling between the sediment and the water column enhances primary productivity. To identify factors that control the strength of this benthic-pelagic coupling we measured sediment characteristics, solute fluxes, and porewater nutrient profiles in spring along a south - north transect in the North Sea crossing distinct regions: the shallow Oyster Grounds closest to the Dutch shore, the shallow Dogger Bank, the 80-m deep central North Sea, and the 150-m deep Fladen Grounds between the north of Scotland and Norway. The data were used to constrain rates of different mineralization processes with the 1-D diagenetic model (OMEXDIA). Surprisingly, we found no major differences in the biogeochemical signature along the 670 km long North Sea transect, despite sediments ranging in median grainsize from 25 to 217 μm, and a permeability range >3 orders of magnitude. Total carbon mineralization ranged between 4 and 13.5 mmol C m−2 d−1, and decreased significantly northward. Oxic mineralization was the dominant mineralization process in all studied sites. Finest, least permeable sediments were found in the Fladen Grounds where highest denitrification rates were recorded, linked to high nitrate concentrations in the overlying water. The coarsest, most permeable sediments of the shallow Dogger Bank represented a transition area between the Oyster Grounds, where oxic mineralization was highest (75–90%), and the central North Sea samples, where anoxic mineralization increased relative to oxic mineralization due to higher bioturbation rates (oxic: 59–72%, anoxic: 27–39%). Overall, denitrification rates increased, while phosphorus removal tended to decrease northward. This contrasting behaviour in nitrogen and phosphorus removal was identified as a possible cause for decreasing DIN:DIP ratios in the water column towards the north

It has been a long-standing question as to whether the interaction between gall-forming insects and their host plants is merely parasitic or whether it may also benefit the host. On its host Rhus chinensis, the aphid Schlechtendalia chinensis induces the formation of closed galls, referred to as horned galls. Typically, mature aphid populations comprise thousands of individuals, which is sufficient to cause the accumulation of high CO2 levels in galls (on average 8-fold higher and up to 16 times than atmospheric levels). Large aphid populations also excrete significant amounts of honeydew, a waste product high in sugars. Based on 13C isotope tracing and genomic analyses, we showed that aphid-derived carbon found in CO2 and honeydew was recycled in gall tissues via photosynthesis and glycometabolism. These results indicated that the aphid-gall system evolved in a manner that allowed nutrient recycling, where the gall provides nutrients to the growing aphid population, and in turn, aphid-derived carbon metabolites provide a resource for the growth of the gall. The metabolic efficiency of this self-circulating system indicates that the input needed from the host plant to maintain aphid population growth less than previously thought and possibly minimal. Aside from the recycling of nutrients, we also found that gall metabolites were transported to other parts of the host plant and is particularly beneficial for leaves growing adjacent to the gall. Taken together, galls in the S. chinensis-Rhus chinensis system are highly specialized structures that serve as a metabolic and nutrient exchange hub that benefits both the aphid and its host plant. As such, host plants provide both shelter and nutrients to protect and sustain aphid populations, and in return, aphid-derived metabolites are channeled back to the host plant and thus provide a certain degree of "metabolic compensation" for their caloric and structural needs.

Microbial eukaryotes (protists) are important contributors to marine biogeochemistry and play essential roles as both producers and consumers in marine ecosystems. Among protists, mixotrophs—those ...

Plants rely on the symbiosis with arbuscular mycorrhizal (AM) fungi to efficiently obtain mineral nutrients, especially phosphate, from the soil. In addition of their role in plant mineral nutrition, AM fungi can offer a range of benefits to their plant hosts in return for photosynthates. Most knowledge on the molecular aspects of this key symbiosis have been obtained from the plant side. However, with the recent availability of AM fungal genome sequences and transcriptomes major progress has been made to get insight into the fungal components that control this interaction. In this review we summarize these recent molecular insights, especially from the AM fungus Rhizophagus irregularis, with a focus on plant-fungus communication, (reciprocal) nutrient exchange, and the genetic make-up of AM fungi.

Pisolithus tinctorius (Pers.) Coker and Couch (Syn.p P. arhizus [Scop.: Pers.] Rauschert) is an ectomycorrhizal fungus that interacts with some of the most important tree genera from temperate forests. In this chapter, we focus on the current knowledge about the beneficial role of P. tinctorius on its host plants. P. tinctorius has an overall positive effect on plant performance, which is often translated into increased shoot growth (height and weight), higher photosynthetic capacity, and mineral nutrient acquisition. Under environmental stress conditions, such as water deficit or soil chemical contamination, plant inoculation with P. tinctorius can afford some degree of tolerance, with mycorrhizal plants showing lower growth decline and less stress symptoms. However, the mechanisms involved in this tolerance have not yet been elucidated.

The nutrient exchange mutualism between arbuscular mycorrhizal fungi (AMFs) and their host plants qualifies as a biological market, but several complications have hindered its appropriate use. First, fungal ‘trading agents’ are hard to identify because AMFs are potentially heterokaryotic, that is, they may contain large numbers of polymorphic nuclei. This means it is difficult to define and study a fungal ‘individual’ acting as an independent agent with a specific trading strategy. Second, because nutrient exchanges occur via communal structures (arbuscules), this temporarily reduces outbidding competition and transaction costs and hence resembles exchanges among divisions of firms, rather than traditional trade on markets. We discuss how fungal nuclei may coordinate their trading strategies, but nevertheless retain some independence, similar to human co-operatives (co-ops).

Long-term field observations of nitrogen [N] and phosphorus [P] concentrations were used to construct nutrient budgets for the western Dutch Wadden Sea between 1976 and 2012. Nutrients come into the western Dutch Wadden Sea via river runoff, through exchange with the coastal zone of the North Sea, neighbouring tidal basins and through atmospheric deposition (for N). The highest concentrations in phosphorus and nitrogen were observed in the mid-1980s. Improved phosphorus removal at waste water treatment plants, management of fertilization in agriculture and removal of phosphates from detergents led to reduced riverine nutrient inputs and, consequently, reduced nutrient concentrations in the Wadden Sea. The budgets suggest that the period of the initial net import of phosphorus and nitrogen switched to a net export in 1981 for nitrogen and in 1992 for phosphorus. Such different behaviour in nutrient budgets during the rise and fall of external nutrient concentrations may be the result of different sediment-water exchange dynamics for P and N. It is hypothesized that during the period of increasing eutrophication (1976–1981) P, and to a lesser degree N, were stored in sediments as organic and inorganic nutrients. In the following period (1981–1992) external nutrient concentrations (especially in the North Sea) decreased, but P concentrations in the Wadden Sea remained high due to prolonged sediment release, whilst denitrification removed substantial amounts of N. From 1992 onwards, P and N budgets were closed by net loss, most probably because P stores were then depleted and denitrification continued. Under the present conditions (lower rates of sediment import and depleted P stores), nutrient concentrations in this area are expected to be more strongly influenced by wind-driven exchange with the North Sea and precipitation-driven discharge from Lake IJssel. This implies that the consequences of climate change will be more important, than during the 1970s and 1980s.

Multiple ectomycorrhizal fungi (EMF) compete to colonise the roots of a host plant, but it is not known whether their success is under plant or fungal control, or a combination of both. We assessed whether plants control EMF colonisation by preferentially allocating more carbon to more beneficial partners in terms of nitrogen supply or if other factors drive competitive success. We combined stable isotope labelling and RNA-sequencing approaches to characterise nutrient exchange between the plant host Eucalyptus grandis and three Pisolithus isolates when growing alone and when competing either indirectly (with a physical barrier) or directly. Overall, we found that nitrogen provision to the plant does not explain the amount of carbon that an isolate receives nor the number of roots that it colonises. Differences in nutrient exchange among isolates were related to differences in expression of key fungal and plant nitrogen and carbon transporter genes. When given a choice of partners, the plant was able to limit colonisation by the least cooperative isolate. This was not explained by a reduction in allocated carbon. Instead, our results suggest that partner choice in EMF could operate through the upregulation of defence-related genes against those fungi providing fewer nutrients.

A laboratory experiment was conducted, to examine how feeding, siphon activity and movement behaviours of a tellinid bivalve, Macomona liliana (Iredale, 1915), were affected by thin surface layers of mud (1–4 mm) and the incorporation of mud into surface (0–2 cm) sediment. Time-lapse photography and porewater pressure sensors were used to characterise changes in behaviour before and after mud addition. Mud addition modified the sediment matrix which had an immediate effect on M. liliana behaviour; significantly affecting the rates of feeding and the degree of porewater pressurisation during feeding events. Surface activity indicated maintenance and clearance of established burrow structures and increased ventilation. Ultimately, subtle modifications in behaviour and sediment hydraulic conductivity may have consequences for nutrient exchange and benthic-pelagic coupling. Our results emphasise the need to consider the impacts of low level stressors when they affect the behaviour of structurally impo...

Surface sediments were collected from the main path of Kuroshio Current (KC) off eastern Taiwan (ETW), and laboratory incubation was conducted for the study of the nutrient exchange at the sediment-water interface. Exchange fluxes of NO3--N, NO2--N, NH4+-N, PO43--P and SiO32--Si under simulated site condition were -0.0866, 0.00146, 0.0634, -0.00812 and -0.181mmolm-2d-1, respectively. This indicated that sediments in the studied area might act as a source of NO2--N and NH4+-N and a sink of NO3--N, PO43--P and SiO32--Si. Factors affecting nutrient exchange fluxes were studied by changing incubation conditions. Compared with some coastal areas in China, the main path of KC off ETW showed relatively low nutrient exchange fluxes at the sediment-water interface. It could be inferred that the sediment-water exchange of nutrients in the main path of KC off ETW had little influence on the downstream nutrient transportation by KC year-round based on the results of this research.

The utero-placental circulation links the maternal and fetal circulations during pregnancy, ensuring adequate gas and nutrient exchange, and consequently fetal growth. However, our understanding of this circulatory system remains incomplete. Here, we discuss how the utero-placental circulation is established, how it changes dynamically during pregnancy, and how this may impact on pregnancy success, highlighting how we may address knowledge gaps through advances in imaging and computational modeling approaches.

A porous tough hydrogel (alginate–polyacrylamide) is successfully synthesized using a photo-gelling polymer as a templating agent. Unlike current porous hydrogels, we present a useful pore-enhancing strategy without sacrificing the mechanical properties of the parent matrix. These porous tough hydrogels, as 3D cell culture scaffolds, can mimic the extracellular matrix and allow maximum nutrient exchange.

Traditionally, the most popular sentences used to describe the arbuscular mycorrhizal symbiosis sound like: “AM fungi form one of the most widespread root symbioses, associating with 80% of land plants. In this symbiosis, the fungus provides the plant host with mineral nutrients, especially phosphate, receiving in turn carbohydrates.” In the last years, the mycorrhiza research field has witnessed a big step forward in the knowledge of the physiology and the mechanisms governing this important symbiosis, that helped plants colonizing the lands more than 400 MYA. The huge expansion of the -omics studies produced the first results on the fungal side, with genomes and transcriptomes of AM fungi being published. In parallel, the need for more sustainable agricultural practices has boosted the research in the field of the plant symbioses, with the final aim of improving plant productivity employing symbiotic microbes as bioinoculants. Beside all the other (positive) effects that mycorrhizal fungi exert on plants, the nutrient exchange is considered as the keystone, and the core mechanism governing this symbiosis. This review will focus on the molecular determinants underneath this exchange, both on the fungal and the plant side. Coming back to the sentence that claims this symbiosis as based on phosphate provided to the plant in return to carbohydrate, we will find that some concepts of this view still stand, while some others have been partly revolutionized.

Bone defects caused by trauma and surgery are common clinical problems encountered by orthopedic surgeons. Thus, a hard-textured, natural-like biomaterial that enables encapsulated cells to obtain the much-needed biophysical stimulation and produce functional bone tissue is needed. Incorporating nanomaterials into cell-laden hydrogels is a straightforward tactic for producing tissue engineering structures that integrate perfectly with the body and for tailoring the material characteristics of hydrogels without hindering nutrient exchange with the surroundings. In this review, recent developments in inorganic nanocomposite hydrogels for bone tissue engineering that are of vital importance but have not yet been comprehensively reviewed are summarized.

Mechanistic models of the impacts of climate change on insects can be seen as very specific hypotheses about the connections between microclimate, ecophysiology and vital rates. These models must adequately capture stage-specific responses, carry-over effects between successive stages, and the evolutionary potential of the functional traits involved in complex insect life-cycles. Here we highlight key considerations for current approaches to mechanistic modelling of insect responses to climate change. We illustrate these considerations within a general mechanistic framework incorporating the thermodynamic linkages between microclimate and heat, water and nutrient exchange throughout the life-cycle under different climate scenarios. We emphasise how such a holistic perspective will provide increasingly robust insights into how insects adapt and respond to changing climates.

Regenerating the diseased tissue is one of the foremost concerns for the millions of patients who suffer from tissue damage each year. Local delivery of cell-laden hydrogels offers an attractive approach for tissue repair. However, due to the typical macroscopic size of these cell constructs, the encapsulated cells often suffer from poor nutrient exchange. These issues can be mitigated by incorporating cells into microscopic hydrogels, or microgels, whose large surface-to-volume ratio promotes efficient mass transport and enhanced cell-matrix interactions. Using microfluidic technology, monodisperse cell-laden microgels with tunable sizes can be generated in a high-throughput manner, making them useful building blocks that can be assembled into tissue constructs with spatially controlled physicochemical properties. In this review, we examine microfluidics-generated cell-laden microgels for tissue regeneration applications. We provide a brief overview of the common biomaterials, gelation mechanisms, and microfluidic device designs that are used to generate these microgels, and summarize the most recent works on how they are applied to tissue regeneration. Finally, we discuss future applications of microfluidic cell-laden microgels as well as existing challenges that should be resolved to stimulate their clinical application.

Environmental sustainability is the modern scientific-field keyword, as a result of the novel awareness about environmental safety that occurred since the “Rio Declaration on Environment and Development” in 1992. For this reason, new and environmentally sustainable analytical techniques have been (and still are being) produced. The main focus of these techniques is not only the use of “green” chemicals (i.e. chemical compounds with a low environmental impact), but also waste reduction through the simplification of analytical procedures such as extractions and purifications. In particular, the modern analytical trend is to find procedures that allow the investigation of complex systems as a whole. Fast field-cycling (FFC) NMR relaxometry is becoming a very reliable technique for the evaluation of the molecular dynamics in soils, sediments and water. It may allow the understanding of the fate of environmental contaminants, and also the mechanisms of nutrient exchange between soils and plant roots. This chapter reports the latest findings in FFC-NMR relaxometry applied to samples from the aforementioned environmental compartments, and the main mathematical models used for data elaboration in environmental field applications.

Brain organoids are an emerging technique for studying human neurodevelopment in vitro, with biomedical implications. However, three-dimensional tissue culture poses several challenges, including lack of nutrient exchange at the organoid core and limited imaging accessibility of whole organoids. Here we present a method for culturing organoids in a micro-fabricated device that enables in situ real-time imaging over weeks with efficient nutrient exchange by diffusion. Our on-chip approach offers a means for studying the dynamics of organoid development, cell differentiation, cell cycle, and motion. © 2018 by John Wiley & Sons, Inc.

Fiber-based materials with microchannels have drawn considerable attention in recent years owing to their ability to mimic intrinsic morphologies of living tissues. Folded morphologies, which are common in vivo, such as in skeletal muscle capillaries and intestine luminal endoderm, play important roles in the achievement of tissue functions. Here, microfibers with folded hollow channels are fabricated. Channel morphologies, such as straight-folded, double-folded and double-helical channels, can be regulated by adjusting flow conditions in the microfluidic devices. To further demonstrate the potential to be used in tissue engineering, intestine and skeletal muscle constructs are fabricated using these microfibers as building blocks. Furthermore, the properties of perfusability, permeability, cytocompatibility and weavability of the microfibers are evaluated. The asymmetric molecular distributions in the microfibers provide promising platforms for the study of nutrient exchange and energy supplement between normal and tortuous tissues. The new features of biofibers and proof-of-concept of tissue constructs with folded morphologies may contribute to the development of regenerative medicine and drug screening in the future.

Microalgae undertake a wide range of mutualistic interactions with bacteria. Here we consider how transcriptomic, metagenomic and metabolomic approaches have been combined with microbiological and biochemical analyses to expand our understanding of algal-bacterial interactions. Identification of the major bacterial species associated with algae indicates that specific bacterial groups, particularly the alpha-Proteobacteria, are found more frequently, suggesting that these may have the means to initiate and maintain symbiotic relationships. Nutrient exchange is frequently the basis of algal-bacterial mutualism, and as the compounds involved are characterised, evidence is accumulating that these are complex and specific molecules, offering opportunities for signalling processes and regulation rather than merely passive diffusion. At the same time, it is clear that the interactions are not static, but can be initiated and broken in response to environmental and developmental cues.

Reciprocal nutrient exchange between the majority of land plants and arbucular mycorrhizal (AM) fungi is the cornerstone of a stable symbiosis. To date, a dogma in the comprehension of AM fungal nourishment has been delivery of host organic carbon in the form of sugars. More recently a role for lipids as alternative carbon source or as a signalling molecule during AM symbiosis was proposed. Here we review the symbiotic requirement for carbohydrates and lipids across developmental stages of the AM symbiosis. We present a role for carbohydrate metabolism and signalling to maintain intraradical fungal growth, as opposed to lipid uptake at the arbuscule as an indispensible requirement for completion of the AM fungal life cycle., Ronelle Roth is supported by the BBSRC grant BB/N008723/1 to Uta Paszkowski.