Mechanistic insight in the selective delignification of wheat straw by three white-rot fungal species through quantitative 13C-IS py-GC–MS and whole cell wall HSQC NMR

Background The white-rot fungi Ceriporiopsis subvermispora (Cs), Pleurotus eryngii (Pe), and Lentinula edodes (Le) have been shown to be high-potential species for selective delignification of plant biomass. This delignification improves polysaccharide degradability, which currently limits the efficient lignocellulose conversion into biochemicals, biofuels, and animal feed. Since selectivity and time efficiency of fungal delignification still need optimization, detailed understanding of the underlying mechanisms at molecular level is required. The recently developed methodologies for lignin quantification and characterization now allow for the in-depth mapping of fungal modification and degradation of lignin and, thereby, enable resolving underlying mechanisms. Results Wheat straw treated by two strains of Cs (Cs1 and Cs12), Pe (Pe3 and Pe6) and Le (Le8 and Le10) was characterized using semi-quantitative py-GC–MS during fungal growth (1, 3, and 7 weeks). The remaining lignin after 7 weeks was quantified and characterized using ¹³C lignin internal standard based py-GC–MS and whole cell wall HSQC NMR. Strains of the same species showed similar patterns of lignin removal and degradation. Cs and Le outperformed Pe in terms of extent and selectivity of delignification (Cs ≥ Le >> Pe). The highest lignin removal [66% (w/w); Cs1] was obtained after 7 weeks, without extensive carbohydrate degradation (factor 3 increased carbohydrate-to-lignin ratio). Furthermore, though after treatment with Cs and Le comparable amounts of lignin remained, the structure of the residual lignin vastly differed. For example, Cα-oxidized substructures accumulated in Cs treated lignin up to 24% of the total aromatic lignin, a factor two higher than in Le-treated lignin. Contrarily, ferulic acid substructures were preferentially targeted by Le (and Pe). Interestingly, Pe-spent lignin was specifically depleted of tricin (40% reduction). The overall subunit composition (H:G:S) was not affected by fungal treatment. Conclusions Cs and Le are both able to effectively and selectively delignify wheat straw, though the underlying mechanisms are fundamentally different. We are the first to identify that Cs degrades the major β-O-4 ether linkage in grass lignin mainly via Cβ–O–aryl cleavage, while Cα–Cβ cleavage of inter-unit linkages predominated for Le. Our research provides a new insight on how fungi degrade lignin, which contributes to further optimizing the biological upgrading of lignocellulose. Electronic supplementary material The online version of this article (10.1186/s13068-018-1259-9) contains supplementary material, which is available to authorized users

Variation in the solubilization of crude protein in wheat straw by different white-rot fungi

Besides their unique ability to depolymerize cell wall components, white-rot fungi are known to assimilate nitrogenous compounds from substrates. This modification may change protein solubility and fermentation in the rumen. To investigate this, the crude protein (CP) in fungal treated wheat straw (3 fungal species, 2 strains each) was fractioned according to the Cornell Net Carbohydrate and Protein System (CNCPS) and assessed for in vitro protein fermentation using a modified gas production technique (IVGPN). Results showed that fungi increased fraction A (instantaneously soluble CP; ∼2.6 times) and B1 (rapidly degradable; ∼1.2 times); and decreased the slowly degradable fraction B3 (∼41.6%) and unavailable fraction C (∼48.3%). The IVGPN of straw treated with Ceriporiopsis subvermispora strains were not different to the control, but increased by 30.2 to 47.1% in Pleurotus eryngii and Lentinula edodes strains. The IVGPN was significantly (P <  0.01) correlated to all fractions of CP, except fraction B1 and B2 (intermediately degradable). All fungi also increased the arginine (∼56%) and lysine (∼15%) contents. This study shows the importance of assessing the protein solubilization by different fungal strains, which can uncover unique mechanisms in the cell wall depolymerization

Dwelling as the life basis of Ukrainians

На прикладі містечок Батурина, Глухова, Борзни та Кролевця у статті розглядається інтер’єр жител населення Чернігово-Сіверщини (друга половина ХVІІІ – середина ХІХ ст.). На основі значного описового матеріалу, стосовно звичаїв і побуту українців, який накопичився в середині і особливо в другій половині ХІХ ст. можна зробити науково-вивірені узагальнення з приводу порівняльної характеристики українців і росіян. Дослідженням цієї теми займалися М. Маркевич, І. Срезнєвський, П. Куліш та ін. Значний внесок до вивчення даної проблематики належить історику М. Костомарову, який виокремив український культурний і традиційно-буттєвий комплекс із загальноросійського, що утрадиційнилось як спільне за понад сторіччя співжиття в рамках однієї імперії. Також у даній статті характеризується поділ оселі на умовні частини та визначаються основні сакральні центри хати. Автор наголошує на глибокому символічному обрядово-ритуальному значенні, яке українці надавали всім предметам хатнього інтер’єру та наголошує на ліричній прив’язаності їх до місця свого проживання.На примере городков Батурина, Глухова, Борзны и Кролевца в статье рассматривается интерьер жилищ населения Чернигово-Северщины во второй половине XVIII – середине XIX вв. На основе материалов, описывающих украинские обычаи и быт, накопившихся в средине, а особенно во второй половине XIX в., можно сделать обобщения по поводу сравнительной характеристики украинцев и русских. Исследованием этой темы занимались Н. Маркевич, И. Срезневский, П. Кулиш и другие ученые. Значительный вклад в изучение данной проблематики принадлежит историку Н. Костомарову, который выделил украинский культурный и традиционно- бытейный комплекс из общероссийского, которые сосуществовали более столетия в границах одной империи. Также в данной статье характеризируется разделение жилища на условные части и определяются основные сакральные центры дома (хаты). Автор отмечает глубокое символическое ритуально-обрядовое значение, которое украинцы придавали всем предметам домашнего интерьера, а также подчеркивает лирическую привязанность населения к месту его проживания.Article deals with the interior of dwellings in Chernihiv-Siverskyi region (in the 2nd half of the ХVІІІ – 1st half of the ХІХ cent.). On the example of towns Baturyn, Glukhiv, Borzna and Krolevets the article deals with the house interiors of the population of Chernihovo-Sivershchyna (the second half of the XVIII – mid. XIX cent.). The analysis is based on considerable descriptive material concerning Ukrainian customs and way of life that has accumulated in the middle and especially in the second half of the XIX cent. and led to scientific adjusted conclusion about the comparative characteristics of Ukrainians and Russians. This topic was researched by M. Markevych, I. Sreznevskyi, P. Kulish and others. A significant contribution to the study of this subject belongs to historian M. Kostomarov, who singled Ukrainian cultural and traditional existential complex out of all-Russian complex, that was considered unified for more than three centuries of coexistence within a single empire. Also, this article characterizes the division of the house on special parts and identifies the main sacred centres of the house. The attention is given to the fact that the Ukrainian housing is associated with many beliefs and rituals. It indicates that the dwelling-house reflects not only people’s ideological and artistic heritage, but also a pragmatic idea. After all, the house seemed a model of nature and the universe, which protected both physically and spiritually. We know that house was not only a place where the family spent most of its life, but it was the family hearth around which ancient and beautiful traditions were preserved. The author emphasizes the deep symbolic ritual value that Ukrainians gave to all subjects of domestic interior and the lyrical attachment to their place of residence. After all, the house had a kind of sacred meaning for its tenants, that is why, to the house and all domestic things people gave some philosophical content. Complexity of representations of the world for humans began from the dwelling and was a dominant through all life. It is revealed that a Ukrainian house with its aesthetic appearance and its interior in particular, is an important factor in the understanding of the Ukrainian people and makes the character unique, and one that is very different from the characteristics of other nations. The author concluded that this topic needs a further study

Multi-messenger observations of a binary neutron star merger

On 2017 August 17 a binary neutron star coalescence candidate (later designated GW170817) with merger time 12:41:04 UTC was observed through gravitational waves by the Advanced LIGO and Advanced Virgo detectors. The Fermi Gamma-ray Burst Monitor independently detected a gamma-ray burst (GRB 170817A) with a time delay of ~1.7 s with respect to the merger time. From the gravitational-wave signal, the source was initially localized to a sky region of 31 deg2 at a luminosity distance of 40+8-8 Mpc and with component masses consistent with neutron stars. The component masses were later measured to be in the range 0.86 to 2.26 Mo. An extensive observing campaign was launched across the electromagnetic spectrum leading to the discovery of a bright optical transient (SSS17a, now with the IAU identification of AT 2017gfo) in NGC 4993 (at ~40 Mpc) less than 11 hours after the merger by the One- Meter, Two Hemisphere (1M2H) team using the 1 m Swope Telescope. The optical transient was independently detected by multiple teams within an hour. Subsequent observations targeted the object and its environment. Early ultraviolet observations revealed a blue transient that faded within 48 hours. Optical and infrared observations showed a redward evolution over ~10 days. Following early non-detections, X-ray and radio emission were discovered at the transient’s position ~9 and ~16 days, respectively, after the merger. Both the X-ray and radio emission likely arise from a physical process that is distinct from the one that generates the UV/optical/near-infrared emission. No ultra-high-energy gamma-rays and no neutrino candidates consistent with the source were found in follow-up searches. These observations support the hypothesis that GW170817 was produced by the merger of two neutron stars in NGC4993 followed by a short gamma-ray burst (GRB 170817A) and a kilonova/macronova powered by the radioactive decay of r-process nuclei synthesized in the ejecta

Multi-messenger Observations of a Binary Neutron Star Merger

On 2017 August 17 a binary neutron star coalescence candidate (later designated GW170817) with merger time 12:41:04 UTC was observed through gravitational waves by the Advanced LIGO and Advanced Virgo detectors. The Fermi Gamma-ray Burst Monitor independently detected a gamma-ray burst (GRB 170817A) with a time delay of ∼ 1.7 {{s}} with respect to the merger time. From the gravitational-wave signal, the source was initially localized to a sky region of 31 deg2 at a luminosity distance of {40}-8+8 Mpc and with component masses consistent with neutron stars. The component masses were later measured to be in the range 0.86 to 2.26 {M}ȯ . An extensive observing campaign was launched across the electromagnetic spectrum leading to the discovery of a bright optical transient (SSS17a, now with the IAU identification of AT 2017gfo) in NGC 4993 (at ∼ 40 {{Mpc}}) less than 11 hours after the merger by the One-Meter, Two Hemisphere (1M2H) team using the 1 m Swope Telescope. The optical transient was independently detected by multiple teams within an hour. Subsequent observations targeted the object and its environment. Early ultraviolet observations revealed a blue transient that faded within 48 hours. Optical and infrared observations showed a redward evolution over ∼10 days. Following early non-detections, X-ray and radio emission were discovered at the transient’s position ∼ 9 and ∼ 16 days, respectively, after the merger. Both the X-ray and radio emission likely arise from a physical process that is distinct from the one that generates the UV/optical/near-infrared emission. No ultra-high-energy gamma-rays and no neutrino candidates consistent with the source were found in follow-up searches. These observations support the hypothesis that GW170817 was produced by the merger of two neutron stars in NGC 4993 followed by a short gamma-ray burst (GRB 170817A) and a kilonova/macronova powered by the radioactive decay of r-process nuclei synthesized in the ejecta.</p

Data from: The scope for nuclear selection within Termitomyces fungi associated with fungus-growing termites is limited

Background: We investigate the scope for selection at the level of nuclei within fungal individuals (mycelia) of the mutualistic Termitomyces cultivated by fungus-growing termites. Whereas in most basidiomycete fungi the number and kind of nuclei is strictly regulated to be two per cell, in Termitomyces mycelia the number of nuclei per cell is highly variable. We hypothesised that natural selection on these fungi not only occurs between mycelia, but also at the level of nuclei within the mycelium. We test this hypothesis using in vitro tests with five nuclear haplotypes of a Termitomyces species. Results: First, we studied the transition from a mixture of five homokaryons (mycelia with identical nuclei) each with a different nuclear haplotype to heterokaryons (mycelia with genetically different nuclei). In vitro cultivation of this mixture for multiple asexual transfers led to the formation of multiple heterokaryotic mycelia, and a reduction of mycelial diversity over time. All heterokaryotic mycelia contained exactly two types of nucleus. The success of a heterokaryon during in vitro cultivation was mainly determined by spore production and to a lesser extent mycelial growth rate. Second, heterokaryons invariably produced more spores than homokaryons implying that homokaryons will be outcompeted. Third, no homokaryotic ‘escapes’ from a heterokaryon via the formation of homokaryotic spores were found, despite extensive spore genotyping. Fourth, in contrast to most studied basidiomycete fungi, in Termitomyces sp. no nuclear migration occurs during mating, limiting the scope for nuclear competition within the mycelium. Conclusions: Our experiments demonstrate that in this species of Termitomyces the scope for selection at the level of the nucleus within an established mycelium is limited. Although ‘mate choice’ of a particular nuclear haplotype is possible during mating, we infer that selection primarily occurs between mycelia with two types of nucleus (heterokaryons)

Genetic variation and combining ability analysis of bruising sensitivity in Agaricus bisporus.

Advanced button mushroom cultivars that are less sensitive to mechanical bruising are required by the mushroom industry, where automated harvesting still cannot be used for the fresh mushroom market. The genetic variation in bruising sensitivity (BS) of Agaricus bisporus was studied through an incomplete set of diallel crosses to get insight in the heritability of BS and the combining ability of the parental lines used and, in this way, to estimate their breeding value. To this end nineteen homokaryotic lines recovered from wild strains and cultivars were inter-crossed in a diallel scheme. Fifty-one successful hybrids were grown under controlled conditions, and the BS of these hybrids was assessed. BS was shown to be a trait with a very high heritability. The results also showed that brown hybrids were generally less sensitive to bruising than white hybrids. The diallel scheme allowed to estimate the general combining ability (GCA) for each homokaryotic parental line and to estimate the specific combining ability (SCA) of each hybrid. The line with the lowest GCA is seen as the most attractive donor for improving resistance to bruising. The line gave rise to hybrids sensitive to bruising having the highest GCA value. The highest negative SCA possibly indicates heterosis effects for resistance to bruising. This study provides a foundation for estimating breeding value of parental lines to further study the genetic factors underlying bruising sensitivity and other quality-related traits, and to select potential parental lines for further heterosis breeding. The approach of studying combining ability in a diallel scheme was used for the first time in button mushroom breeding

data on mycelial growth, nodulation and genotyping

The file contains data on Termitomyces mycelial growth rate and asexual spore yield, and on genotyping data from the mixing experiment