Different Stages Of Decomposition Research Articles

The Influence of Forest Litter Characteristics on Bacterial and Fungal Community Diversity in the Picea crassifolia Ecosystem on the Qinghai–Tibet Plateau

The biodiversity and activity of microorganisms are crucial for litter decomposition, but how litter traits at different stages of decomposition drive changes in microbial communities has yet to be thoroughly explored. In the typical alpine hilly area of the Qinghai–Tibet Plateau, three types of litter at different decomposition stages were selected under a natural Picea crassifolia (Picea crassifolia Kom.) forest: undecomposed (A-1), partially decomposed (A-2), and fully decomposed (A-3). By measuring physicochemical indicators, microbial diversity, and the composition of the litter at different decomposition stages, this study investigates the community changes and responses of bacteria to litter characteristic changes at different decomposition levels. The results show that with the increase in decomposition level, bacterial diversity increases, community structure changes, and network complexity gradually increases, while the changes in fungal communities are insignificant. Structural equation modeling indicates that the first principal component (PC1) of litter properties is significantly negatively correlated with bacterial diversity and positively correlated with bacterial community composition. There is no significant correlation between fungal diversity and community composition, indicating a closer relationship between bacteria and litter characteristics than fungi. In summary, with an increase in litter decomposition level, the diversity and network complexity of bacterial and fungal communities will significantly increase, which is related to the changes in various litter characteristics. This study provides a scientific basis for the regulatory mechanism of litter decomposition and turnover in the alpine hilly area of the Qinghai–Tibet Plateau, specifically in Picea crassifolia forests.

Changes and driving factors of microbial community composition and functional groups during the decomposition of Pinus massoniana deadwood.

Clarifying changes in the microbial community in deadwood at different stages of decomposition is crucial for comprehending the role of deadwood in the biogeochemical processes and the sustainability of forest development. However, there have been no reports on the dynamics of microbial community during the decomposition of Pinus massoniana. We used the "space-for-time" substitution to analyze the characteristics of microbial community changes and the key influencing factors in the P. massoniana deadwood during different decomposition stages by 16S and ITS rRNA gene sequencing. The results suggest that the microbial community structure of the early decomposition (decay class I) was significantly different from the other decay classes, while the diversity and richness of the microbial community were the highest in the late decomposition (decay class V). The Linear Discriminant Analysis Effect Size analysis revealed that most bacterial and fungal taxa were significantly enriched in decay classes I and V deadwood. During the initial stages of decomposition, the relative abundance of the bacterial functional group responsible for carbohydrate metabolism was greater than the later stages. As decomposition progressed, the relative abundance of saprophytic fungi gradually decreased, and there was a shift in the comparative abundance of mixed saprophytic-symbiotic fungi from low to high before eventually decreasing. Total organic carbon, total nitrogen, carbon-to-nitrogen ratio, total potassium, total phenol, condensed tannin, lignin, and cellulose were significantly correlated with microbial community structure, with the carbon-to-nitrogen ratio having the greatest effect. Our results indicate that the physicochemical properties of deadwood, microbial community structural composition and functional group changes were related to the decay class, among which the carbon-to-nitrogen ratio may be an important factor affecting the composition and diversity of microbial communities.

Catch me if you can-emission patterns of human bodies in relation to postmortem changes.

The present study examines for the first time the emission patterns and olfactory signatures of 9 complete human corpses of different stages of decomposition. Air sampling was performed inside the body bags with solid sorbents and analysed by coupled gas chromatography-mass spectrometry after thermal desorption (TD-GC-MS). Furthermore, odour-related substances were detected by gas chromatography-olfactometry (GC-O). Sulfurous compounds (mainly dimethyl di- and trisulfide) were identified as most important to the odour perception. Around 350 individual organic substances were detected by TD-GC-MS, notably sulfurous and nitrogenous substances as well as branched alkanes, aldehydes, ketones, alcohols, carboxylic acids, carboxylic acid esters and ethers. A range of terpenes was detected for the first time in a characteristic emission pattern over all decomposition stages. Concentrations of the substances varied greatly, and no correlation between the emission patterns, thestage of decomposition and the cause of deathcould be found. While previous studies often analysed pig cadavers or only parts of human tissue, the present study shows the importance of analysing complete human corpses over a range of decomposition stages. Moreover, it is shown that using body bags as a kind of "emission test chamber" is a very promising approach, also because it is a realistic application considering the usual transport and store of a body before autopsy.

Humic fractions of soil carbon under agroforestry system in altitude swamp Pernambucano

MOS (soil organic matter) is a natural carbon reservoir, and divided into different stages of decomposition according to its solubility and structural complexity. In view of this context, this work aimed to quantify the carbon content in the humic fractions of the soil organic matter under an agroforestry system in three toposequences in the swamp of altitude in Pernambuco, Brazil. The study was carried out on the Yaguara farm, and the studied areas were native forest and three toposequences of agroforestry system. Soil samples were collected in trenches 1.5 x 1.5 m, at depths 0-20, 20-40 and 40-60 cm, with four replications. The carbon concentrations in the humic fractions of the soil decreased with increasing depth. The area with agroforestry system had the highest concentrations of carbon in the humic fractions. The stocks of humic fractions found in the agroforestry system area showed higher average values in the top area 5.62, 9.72 and 22.53 Mg ha-1 in relation to native forest 4.84, 8.28 and 19.20 Mg ha-1, respectively for fulvic acid, humic acid and humine. Among the evaluated areas, the soil with agroforestry system top area has great potential to increase the carbon storage in the humic fractions of the soil.

Metagenomics reveals the underestimated role of bacteria in the decomposition of downed logs in forest ecosystems

Downed logs are important structural and functional elements in the material flow of global forest ecosystems. They provide a rich natural substrate resource for microorganisms; however, current laboratory-based methods cannot fully elucidate the complex process of microbial decomposition of downed logs. Therefore, our study investigated the microbial community structure, succession patterns, and underlying environmental factors controlling the decomposition of Pinus tabulaeformis and Quercus aliena var. acuteserrata downed logs at different stages of decomposition in Chinese forest ecosystems. The genomes of the microorganisms present on the logs during different stages were therefore sequenced, and functional genes were annotated and analyzed using the Kyoto Encyclopedia of Genes and Genomes and Carbohydrate-Active enZYmes databases. We found that bacterial abundance was always higher than fungal abundance throughout the decomposition process, reflecting their strong competitive ability. Microbial community structure and function were similar in the early stage (I) and late stages (IV, V) of log decomposition, but those of the middle stages (II, III) differed. With the decomposition of downed logs of Q. aliena var. acuteserrata, there was a fungal succession pattern from Ascomycota to Basidiomycota to Mucoromycetes, but this trend did not occur for P. tabulaeformis. The density, moisture and elemental content of downed logs were the main factors affecting the microbial community. Finally, microbially mediated functions were mainly related to the metabolism of amino acids, carbohydrates and various small molecule carbohydrate enzymes, cellulases, and chitinases in glycoside hydrolases; the taxa sources of the main functions were primarily Proteobacteria and Firmicutes bacteria, reflecting the functional importance of bacteria in the process of downed log decomposition. We conclude that bacteria always play an important role in the process of downed log decomposition and that their role may be far underestimated. Therefore, we believe that the next step should be to expand the study of downed log bacteria, to further clarify the ecological functions of the bacteria on downed logs in natural environments and their relationship with fungi, which may help shed light on the complex decomposition process of downed logs.

New Ethynylphenylborasilsesquioxanes-Their Reactivity and Behavior during Thermal Decomposition.

In this paper, a new type of borasilsesquioxanes was synthesized through a condensation process, and its reactivity in catalytic hydrosilylation reactions with silanes, siloxanes, and silsesquioxanes was investigated. The obtained compounds were mostly obtained in >90% yield. They were fully characterized using spectroscopic (1H, 13C, 29Si NMR) and spectrometric (MALDI-TOF-MS) methods. The next stage of the research involved studying the thermogravimetric properties of the borasilsesquioxanes. By analyzing the different stages of decomposition using spectroscopic techniques (NMR, ATR-FTIR, Raman) and microscopic imaging, it was found that the structure of the borasilsesquioxanes changed during the pyrolysis process and polymer compounds were formed.

Analysis of Exhumations Carried Out in Three Divisions of Sindh

Aim: To determine the causes of death on exhumation in three divisions of Sindh, Pakistan Study Design: Cross-sectional Place and Duration of Study: Department of Pathology, Chandka Medical College, Larkana Methods: 131 exhumations carried over 1 year were included in the study. In accordance with protocol, the graves were first identified and body was removed from it. Routine autopsy was carried out. Written consent for obtaining data was taken from the relatives present and a standard proforma was used to note findings. Samples for histopathology were also taken and cause of death was evaluated. After taking relevant information, the bodies were buried in accordance with the religious and cultural norms of the relatives. Data was entered and analyzed using SPSS 22.0. Results: Males were more commonly exhumed. 21-40 years age group was most commonly involved. Most exhumations were carried out in Larkana. Most common weapon used was forced blunt trauma. Almost all bodies were at different stages of decomposition. We then observed the type of weapon/medium used. All 131 cases were of unnatural death. We observed that the most common weapon used was a hard blunt object (n=41; 31.29%), water causing drowning (n=34; 25.95%), sharp forced trauma (n=21; 16.03%) and strangulation (n=19:14.50%) were commonly used. Whereas, the least commonly used were firearms (n=16; 12.21%). According to our observation, 57.25% (n=75) were partially decomposed, 40.45% (n=53) had advanced decomposition whereas 2.29% (n=3) had no decomposition at all. Practical Implication: Analysis of exhumations is crucial for uncovering forensic evidence, resolving criminal cases, and providing closure to families. It helps ascertain causes of death, identify potential foul play, and contribute to the justice system's integrity. Additionally, exhumation analysis aids in refining investigative techniques and advancing forensic science. Conclusion: We recommend exhumation when required be carried out in females as well. We also recommend early exhumation in cases of suspected foul-play. Our data may help in future planning of policies regarding exhumation. Keywords: Exhumation; 3 Divisions of Sindh; Decomposition, Causes of Death, Drowning, Firearm Injuries, Weapon

Dead Wood Elements Composition in Different Tree Species and Stages of Decay in the Broad-Leaved Forests of the Kaluzhskie Zaseki Reserve

The content and mass concentration of eight chemical elements Al, Ca, Cu, K, Mg, Mn, P, and Zn were analysed in dead wood of eight tree species at five stages of decomposition. Wood samples were taken at the site of the mass windfall of 2006 in a multispecies broadleaved forest in the Kaluzhskie Zaseki nature reserve. Deadwood of seven deciduous trees species was studied: maple (Acer platanoides), birch (Betula pendula), common ash (Fraxinus excelsior), common aspen (Populus tremula), English oak (Quercus robur), linden (Tilia cordata), rough elm (Ulmus glabra), as well as one coniferous tree species – Norway spruce (Picea abies). A series of one-way analyses of variance was carried out to assess the influence of the species and the stage of deadwood decomposition (including the zero stage for control samples) on the density, content of elements and their mass concentration. Tree species most clearly differed in the content and mass concentration of Mn, Zn, Mg, Ca, and K: R2 varied from 50 to 23% for the content and from 53 to 19% for the mass concentration of elements of the indicated series. The leaders in the content of these elements were the following species: Mn – maple, birch, spruce, linden; Zn – birch and aspen; Mg – maple, elm; Ca – elm; K – linden, elm. The stages of wood decomposition turned out to be a significant factor of variation for the content of Mn, P, Cu, Zn and Ca: R2 varied from 22 to 16%. During the destruction of wood trunks, a significant increase in the content of these elements occurred. Maintenance of cycles of biophilic elements is more successfully implemented in the presence of deadwood of different species at different stages of decomposition.

Exploring postmortem succession of rat intestinal microbiome for PMI based on machine learning algorithms and potential use for humans

The microbial communities may undergo a meaningful successional change during the progress of decay and decomposition that could aid in determining the post-mortem interval (PMI). However, there are still challenges to applying microbiome-based evidence in law enforcement practice. In this study, we attempted to investigate the principles governing microbial community succession during decomposition of rat and human corpse, and explore their potential use for PMI of human cadavers. A controlled experiment was conducted to characterize temporal changes in microbial communities associated with rat corpses as they decomposed for 30 days. Obvious differences of microbial community structures were observed among different stages of decomposition, especially between decomposition of 0–7d and 9–30d. Thus, a two-layer model for PMI prediction was developed based on the succession of bacteria by combining classification and regression models using machine learning algorithms. Our results achieved 90.48% accuracy for discriminating groups of PMI 0–7d and 9–30d, and yielded a mean absolute error of 0.580d within 7d decomposition and 3.165d within 9–30d decomposition. Furthermore, samples from human cadavers were collected to gain the common succession of microbial community between rats and humans. Based on the 44 shared genera of rats and humans, a two-layer model of PMI was rebuilt to be applied for PMI prediction of human cadavers. Accurate estimates indicated a reproducible succession of gut microbes across rats and humans. Together these results suggest that microbial succession was predictable and can be developed into a forensic tool for estimating PMI.

Mulching vs. organic soil amendment: Effects on adsorption-desorption of herbicides

Mulching and organic soil amendment are two agricultural practices that are being increasingly used to preserve soil from degradation, although they may modify the fate of herbicides when applied in soils subjected to these practices. This study has set out to compare the impact of both agricultural practices on the adsorption-desorption behaviour of the herbicides S-metolachlor (SMOC), foramsulfuron (FORAM), and thiencarbazone-methyl (TCM) involving winter wheat mulch residues at different stages of decomposition and particle size, and unamended soils or those amended with mulch. The Freundlich Kf adsorption constants of the three herbicides by mulches, and unamended and amended soils ranged between 1.34 and 65.8 (SMOC), 0–34.3 (FORAM), and 0.01–1.10 (TCM). The adsorption of the three compounds was significantly higher in mulches than in soils (unamended and amended). The adsorption of SMOC and FORAM increased significantly with mulch decomposition, with this positive impact also being observed on the adsorption of FORAM and TCM after mulch milling. Simple and multiple correlations between mulches, soils, and herbicide properties, and adsorption-desorption constants (Kf, Kd, Kfd) reflected the organic carbon (OC) content and/or dissolved organic carbon (DOC) content of the adsorbents as main variables controlling the adsorption and/or desorption of each herbicide. The statistic R2 revealed that >61 % of the variability in the adsorption-desorption constants could be explained by jointly considering the OC of mulches and soils and the hydrophobicity (for Kf) or water solubility of herbicides (for Kd or Kfd). The same trend observed for Kfd desorption constants as for Kf adsorption ones resulted in higher percentages of herbicide remaining adsorbed after desorption in amended soils (33 %–41 % of SMOC, 0 %–15 % of FORAM, and 2 %–17 % of TCM) than in mulches (< 10 %). The results reveal a higher efficiency of organic soil amendment than mulching as an agricultural practice for immobilising the herbicides studied when winter wheat mulch residues are used as a common adsorbent, and as a better strategy for avoiding groundwater contamination.

Estimation of Late Postmortem Interval: Where Do We Stand? A Literature Review.

Estimating time since death can be challenging for forensic experts, and is one of the most challenging activities concerning the forensic world. Various methods have been assessed to calculate the postmortem interval on dead bodies in different stages of decomposition and are currently widely used. Nowadays, the only well-recognized dating technique is carbon-14 radioisotope measurement, whereas other methods have been tested throughout the years involving different disciplines with different and sometimes not univocal results. Today, there is no precise and secure method to precisely determine time since death, and late postmortem interval estimation remains one of the most debated topics in forensic pathology. Many proposed methods have shown promising results, and it is desirable that with further studies some of them might become acknowledged techniques to resolve such a difficult and important challenge. The present review aims at presenting studies about the different techniques that have been tested in order to find a valuable method for estimating time since death for skeletal remains. By providing a comprehensive overview, the purpose of this work is to offer readers new perspectives on postmortem interval estimation and to improve current practice in the management of skeletal remains and decomposed bodies.

Drone-Based Thermal Imaging in the Detection of Wildlife Carcasses and Disease Management

Because animal carcasses often serve as reservoirs for pathogens, their location and removal are crucial in controlling the spread of diseases. During carcass decomposition, heat is emitted due to microbial activity and the development of maggots. Recent studies have shown that infrared sensors can be used to locate animal carcasses, but little is known about the factors influencing detection success. In this study, we investigated the potential of infrared technology to locate wild boar carcasses, as they play an important role in the spread of African swine fever. Specifically, we tested the effects of environmental and carcass conditions on the detection probability. A drone-based thermal camera was used to collect data during 379 flyovers of 42 wild boar carcasses in different stages of decomposition between September 2020 and July 2021. Generalized mixed-effect models and conditional inference trees were used to identify the environmental and carcass conditions that influenced the detection probability. Our results showed that the thermal camera accurately measured carcass temperature (R2 = 0.75, RMSE = 5.89°C). The probability of finding carcasses was higher in open habitats with air temperatures &gt;3.0°C and thus conducive to maggot development (detection rate ≤80%). A forest canopy openness &gt;29.3% and cloudy conditions or flights at dawn increased the detection rate. Moreover, carcasses infested with large amounts of maggots could be detected even in habitats with a more extensive canopy cover, whereas in dense forests, the detection probability was limited (&lt;25%). Carcasses in an advanced stage of decomposition could still be detected as long as the difference between the carcass temperature and the air temperature was &gt;6.4°C (≤62%). Our study demonstrates the utility of thermal imaging in searching for wild boar carcasses under specific environmental and carcass conditions and thus its use in supporting ground searches.

An interdisciplinary forensic approach for human remains identification and missing persons investigations

AbstractThe resolution of unidentified human remains (UHR) and long‐term missing persons (LTMP) cases is paramount for administrative, legal, and humanitarian reasons. There are various forensic profiling methods for human identification; however, their utility is dependent on several factors. First, UHR can be found in different stages of decomposition, so the availability and diversity of post‐mortem (PM) information will differ. Second, the availability and totality of the LTMP's ante‐mortem (AM) information will differ. Therefore, the suitability of existing methods will be dependent on the quality and quantity of PM and/or AM data available for comparison. Visual recognition is the simplest and quickest method, but typically not practiced or possible, owing to the altered, fragmented, or skeletonized state of UHR. Primary forensic profiling methods involve the comparison of fingerprint, dental, DNA, and medical data. Secondary forensic profiling methods from anthropology, radiology, geochemistry, and anatomy disciplines can provide supplementary evidence to support comparative identification approaches. Emerging forensic molecular technologies such as genomics, microbiomics, epigenetics, and proteomics, together with individual digital footprints from personal devices, offer new investigative leads for establishing identity. However, despite the success of these individual methods, their limitations must be considered when used in isolation. Through the development of a guiding forensic examination framework, this review endorses an interdisciplinary response to unidentified and missing persons investigations, where various forensic specialists collaboratively examine UHR using a suite of contemporary forensic profiling methods to produce multiple and/or different lines of evidence to link them effectively, efficiently, comprehensively, and systematically to LTMP.This article is categorized under:Forensic Science in Action/Crime Scene Investigation &gt; Special Situations and InvestigationsForensic Biology &gt; DNA Testing in Disaster Victim and Missing Persons IdentificationForensic Medicine &gt; Medicolegal Death Investigation SystemsJurisprudence and Regulatory Oversight &gt; Interdisciplinary Collaboration

Canopy Gaps Control Litter Decomposition and Nutrient Release in Subtropical Forests

The formation of a canopy gap results in changes to the microenvironment which, in turn, affect litter decomposition and nutrient release. However, the mechanisms underlying these effects in differently sized gaps and non-gaps remain poorly understood. To address this gap in knowledge, we selected three large gaps (above 150 m2), three medium gaps (50–100 m2), three small gaps (30–50 m2), and three non-gaps with basically the same site conditions. We then used the litter bag method to investigate leaf and branch litter decomposition over a year in a Castanopsis kawakamii natural forest with the aim of characterizing the litter mass remaining and the nutrient release in canopy gaps and non-gaps. Our results revealed that the remaining litter mass of leaf and branch litter was lower in medium gaps compared to other gaps, and leaf litter decomposed faster than branch litter. Environmental factors were identified as the primary drivers of total carbon and nitrogen release during litter decomposition. Gap size (canopy openness), taxonomic Margalef index, the Brillouin index of soil microbes, soil total nitrogen content, soil pH value, and average air temperature were identified as the main factors driving carbon and nitrogen release from branch litter. In the late decomposition stage, the taxonomic Pielou index, soil total potassium content, soil water content, and average relative air humidity were the main drivers of nutrient release from branch litter. The soil water content and average relative air humidity were also found to be the main factors affecting the nutrient release from leaf litter throughout the different stages of decomposition. Overall, our study highlights the impact of canopy gaps on microenvironmental variation, taxonomic community diversity, and soil microbial functional diversity and how these factors ultimately influence litter decomposition and nutrient release. Our findings provide an important foundation for further research into soil nutrient cycling in subtropical natural forests.

Assessment of Earthworm Services on Litter Mineralisation and Nutrient Release in Annual and Perennial Energy Crops (Zea mays vs. Silphium perfoliatum)

Abundant and functionally diverse earthworm communities in perennials deliver ecosystem services like increasing nutrient availability by incorporating organic matter. This study aimed to analyse the decomposition of annual and perennial energy crop residues, and the subsequent nutrient release, depending on earthworm functional diversity. In a laboratory experiment, two ecological earthworm groups—anecics (detritivorous Lumbricus terrestris (L.)) and endogeics (geophagous Aporrectodea caliginosa and A. rosea)—were incubated with wilted cup plant (Silphium perfoliatum) and maize (Zea mays) litter for 4 or 8 weeks. Decomposition and consumption rates were calculated. The C, N and P in litter and casts were analysed. Mineralisation was a function of earthworm biomass and the number of individuals. Functional diversity had no beneficial effect. Decomposition was found to be highest in treatments with detritivorous earthworms, i.e., higher earthworm biomass, yet consumption and nutrient turnover in relation to earthworm biomass were higher in treatments with geophages indicating enhanced competition. N limitation became apparent in both litter treatments and was predominant with cup plant litter. N limitation and recalcitrant cell wall compounds affected consumption rates and the egestion of total C and P. While N in casts was lower than expected, P was increased. We observed that the effects manifested at different stages of decomposition of maize and cup plant, highlighting differences in temporal development of decomposition and nutrient turnover between litter types. Our results indicate that earthworms promote decomposition of recalcitrant litter and nutrient turnover, but N limitation may hamper nutrient release. Cup plant systems offer a suitable habitat for soil-dwelling organisms, but management approaches must consider the adequate input of organic matter as an energy and nutrient source to enhance ecosystem service provision.

Application of the Biolog EcoPlate™ technique for assessing the microbial metabolic diversity in moss profiles of continental Antarctica

Little is known about metabolic capabilities of microbial assemblages in continental Antarctic to utilize diverse carbon sources within moss profiles consisting of live, senescent, and dead moss tissues in different stages of decomposition. In the present study, microbial metabolic diversity was determined using Biolog EcoPlate™ for samples of Bryum pseudotriquetrum/B. archangelicum complex collected at five sites located in coastal outcrops of the Lützow-Holm Bay area (Queen Maud Land), East continental Antarctica, and effects of chemical, biological, and physical properties of the moss tissues were explored. The average well-color development, the number of substrates utilized, Simpson's diversity index and equitability of the microbial substrate utilization, and the utilization of carbohydrates, amino acids/amines, carboxylic acids, and polymers varied significantly among the five sites and among four layers of moss profiles. Principal component analysis showed that the utilization of L-asparagine, L-arginine, D-galacturonic acid, Tween 40, Tween 80, and D-mannitol mainly contributed to the variance in the microbial metabolic diversity between sites and moss profiles. The linear mixed models indicated that the relative content of recalcitrant organic components, the number of fungal species, and the water content of moss tissues affected the diversity of microbial utilization of carbon sources.

Effects of Fungi on Soil Organic Carbon and Soil Enzyme Activity under Agricultural and Pasture Land of Eastern Türkiye

Soil organic matter (SOM) is a heterogeneous mixture of materials ranging from fresh plant tissues to highly decomposed humus at different stages of decomposition. Soil organic carbon (SOC) status is directly related to the amount of organic matter in soil and therefore is generally used to measure it. Soil carbon sequestration refers to the removal of carbon (C) containing substances from the atmosphere and its storage in soil C pools. The soil microbial community (SMC) plays an important role in the C cycle, and its activity is considered to be the main driver of differences in C storage potential in soil. The composition of SMC is crucial for maintaining soil ecosystem services, as the structure and activity of SMC also regulate the turnover and distribution of nutrients, as well as the rate of soil organic matter (SOM) decomposition. Here, we applied fungi on the soils taken from two fields, one used as a pasture and one for agriculture (wheat cultivation), in a histosol in the eastern part of Türkiye and investigated the changes in the organic carbon and enzyme activity contents of the soils at the end of the 41-day incubation period. In the study, four different fungal species (Verticillium dahliae (SOR-8), Rhizoctonia solani (S-TR-6), Fusarium oxysporum (HMK2-6), and Trichoderma sp.) were used and catalase, urease, and alkaline phosphatase activities were examined. Results showed that the values of SOC were V. dahliae (7.46%), Trichoderma sp. (7.27%), R. solani (7.03%), Control (6.97%), and F. oxysporum (6.7%) in pastureland and were V. dahlia (4.72%), control (4.69%), F. oxysporum (4.65%), R. solani (4.37%), and Trichoderma sp. (4.14%) in agricultural land, respectively. SOC and soil enzyme activities were significantly affected by land use types (p &lt; 0.05). The higher SOC and enzyme activities were observed in pastureland. Finally, it was determined that soil organic carbon and soil enzyme activities were affected by fungi. This study is important in terms of revealing that the effects of fungi on soil organic carbon and enzyme activities are different in various land types.

Fungi in the litter of Andreadoxa flava and Nectandra membranacea in Southern Bahia

Abstract In the present research were studied fungi on the litter of Andreadoxa flava and Nectandra membranacea, in a remaining area of the Atlantic Forest in Ilhéus, BA. The mycota of those plants had not been studied. Samples were obtained in three collections between October 2018 and July 2019, during which 20 leaves at different stages of decomposition were collected per plant species. The leaves were washed and stored in wet chambers. Fungal preparations were used for microscopic analysis and identification of species. A total of 25 genera and 32 fungal species were found, 26 in the litter of A. flava and 22 of N. membranacea. Sixteen genera were associated with both plants. Microcallis was identified for the first ever associated with A. flava, a species native to the Atlantic Forest, and the taxon Thozetella falcata, was found for the first time in Bahia in the same plant. This is the first report of Parasympodiella lauri on N. membranacea in Brazil. The mycota found was analyzed taxonomically and for its diversity. Further studies on the mycota associated with the two plants must be carried out, particularly for A. flava as it is nearly extinct in nature.

Tripartite Symbiotic Digestion of Lignocellulose in the Digestive System of a Fungus-Growing Termite.

Fungus-growing termites are efficient in degrading and digesting plant substrates, achieved through the engagement of symbiotic gut microbiota and lignocellulolytic Termitomyces fungi cultivated for protein-rich food. Insights into where specific plant biomass components are targeted during the decomposition process are sparse. In this study, we performed several analytical approaches on the fate of plant biomass components and did amplicon sequencing of the 16S rRNA gene to investigate the lignocellulose digestion in the symbiotic system of the fungus-growing termite Odontotermes formosanus (Shiraki) and to compare bacterial communities across the different stages in the degradation process. We observed a gradual reduction of lignocellulose components throughout the process. Our findings support that the digestive tract of young workers initiates the degradation of lignocellulose but leaves most of the lignin, hemicellulose, and cellulose, which enters the fresh fungus comb, where decomposition primarily occurs. We found a high diversity and quantity of monomeric sugars in older parts of the fungus comb, indicating that the decomposition of lignocellulose enriches the old comb with sugars that can be utilized by Termitomyces and termite workers. Amplicon sequencing of the 16S rRNA gene showed clear differences in community composition associated with the different stages of plant biomass decomposition which could work synergistically with Termitomyces to shape the digestion process. IMPORTANCE Fungus-farming termites have a mutualist association with fungi of the genus Termitomyces and gut microbiota to support the nearly complete decomposition of lignocellulose to gain access to nutrients. This elaborate strategy of plant biomass digestion makes them ecologically successful dominant decomposers in (sub)tropical Old World ecosystems. We employed acid detergent fiber analysis, high-performance anion-exchange chromatography (HPAEC), high-performance liquid chromatography (HPLC), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), pyrolysis gas chromatography-mass spectrometry (Py-GC-MS), and amplicon sequencing of the 16S rRNA gene to examine which lignocellulose components were digested and which bacteria were abundant throughout the decomposition process. Our findings suggest that although the first gut passage initiates lignocellulose digestion, the most prominent decomposition occurs within the fungus comb. Moreover, distinct bacterial communities were associated with different stages of decomposition, potentially contributing to the breakdown of particular plant components.

Soil Amendments with Spearmint, Peppermint and Rosemary Enhance the Community of Free-Living Nematodes and Improve Soil Quality, While Having Strikingly Different Effects on Plant Growth.

Sustainable farming practices aim to replace agrochemicals with plant-based alternatives to increase productivity and soil quality. To evaluate the potential use of aromatic plants as soil amendments in tomato seedbeds, in a greenhouse experiment, we used spearmint, peppermint, and rosemary, separately, as soil amendments, in pots sown with tomato, and studied their effect on seedling growth, soil nutrients, and the soil nematode community in terms of trophic and functional structure, metabolic footprint, and genera composition. Non-amended soil was used in the control pots. We further explored the dynamics of the plant–soil–nematode interactions by using aromatic plants at different stages of decomposition (0, 28, and 56 days). Incorporating aromatic plants into the soil led to the proliferation of free-living nematodes, especially of the opportunistic kind, resulting in vigorous and enriched soil. This was more pronounced in the case of the spearmint and peppermint, which also increased the tomato growth. The high soil nutritional status and enhanced plant growth were most prominent when the aromatic plants were left for 28 days to decompose in the soil before sowing. Compared with the mint plants, the rosemary had similar, yet less intense, effects on the soil community, but completely inhibited the growth of the tomato seedlings. Therefore, it is not recommended for use as a soil amendment in tomato seedbeds.