Microbial Origin Research Articles

The Ballynoe Stratiform Barite Deposit, Silvermines, County Tipperary, Ireland

The Ballynoe barite deposit is a conformable, mineralised horizon of Lower Carboniferous age overlying a diastem and mass faunal extinction demarking the transition from a quiet water environment to one of dynamic sedimentation. The geometry of the barite orebody correlates with the palaeotopography of the footwall, which acted as an important control over the lateral extent, thickness, and nature of the mineralisation. Sedimentary features within the barite horizon suggest that it was precipitated in the form of a cryptocrystalline mud which underwent major diagenetic modification resulting in extensive stylolitisation, recrystallisation, and remobilisation. There is abundant and compelling geological and isotopic evidence for early local exhalation from the presence of a hydrothermal vent fauna consisting of delicately pyritised worm tubes and haematised filaments of apparent microbial origin. The worm tubes are remarkably similar to examples from modern and ancient volcanic-hosted massive sulphide deposits, and the filamentous microfossils have similarities to modern Fe-oxidising bacteria. Strontium in the barite has an 87Sr/86Sr ratio indistinguishable from seawater between 350 and 344 Ma whilst oxygen isotopes from barite and chert suggest a diagenetic origin in equilibrium with such seawater around 60–70 °C. Fluid inclusion studies have shown that, in general, low temperature inclusions are very saline (20%–25%) whilst at higher homogenisation temperatures they are more dilute (9%–12%).

Antimicrobial and Cytotoxic Naphthoquinones from Microbial Origin: An Updated Review.

Naphthoquinones (NQs) are small molecules bearing two carbonyl groups. They have been the subject of much research due to their significant biological activities such as antiproliferative, antimicrobial, anti-inflammatory, antioxidant, and antimalarial effects. NQs are produced mainly by bacteria, fungi and higher plants. Among them, microorganisms are a treasure of NQs with diverse skeletons and pharmacological properties. The purpose of the present study is to provide a comprehensive update on the structural diversity and biological activities of 91 microbial naphthoquinones isolated from 2015 to 2022, with a special focus on antimicrobial and cytotoxic activities. During this period, potent cytotoxic NQs such as naphthablin B (46) and hygrocin C (30) against HeLa (IC50=0.23 μg/ml) and MDA-MB-431 (IC50=0.5 μg/ml) cell lines was reported, respectively. In addition, rubromycin CA1 (39), exhibited strong antibacterial activity against Staphylococcus aureus (MIC of 0.2 μg/ml). As importance bioactive compounds, NQs may open new horizon for treatment of cancer and drug resistant bacteria. As such, it is hoped that this review article may stimulates further research into the isolation of further NQs from microbial, and other sources as well as the screening of such compounds for biological activity and beneficial uses.

Unveiling the anticancer potential of L-Asparaginase (ASNase) from novel Streptomyces isolate HB2AG: Purification and characterization study

L-asparaginase (ASNase) obtained from microbial origins is a significant enzyme in the commercial sphere, crucial for the treatment of acute lymphoblastic leukemia. In the current investigation, we isolated ASNase through techniques involving ammonium sulfate precipitation and DEAE sepharose anion exchange column chromatography, revealing a molecular weight of 35 kDa. The enzyme exhibited its peak activity at pH 8 and 40°C, maintaining approximately 99% of its enzymatic effectiveness. The Michaelis constant (Km) and maximum velocity (Vmax) were determined to be 0.0021 M and 714.3 µM/min, respectively. ASNase was found to be non-toxic on HEK293 cells and selectively effective against breast cancer, hepatocellular carcinoma cells, colorectal adenocarcinoma cells, Human lung cancer cell line, Neck squamous cells, and Human head carcinoma cells. Hepatocellular carcinoma cells exhibited remarkable responsiveness to ASNase, displaying an IC50 of 23 µg/mL. This led to observable changes in nuclear morphology indicative of apoptosis, as evidenced by DAPI and Annexin V-FITC staining. ASNase also showed cell migration potential on HEK293 cells. Streptomyces HB2AG ASNase’s dynamic functioning across pH and temperature ranges, as well as its stability at 40°C and cytotoxic potential, make it a promising pharmaceutical candidate for various applications.

Microbially induced fabrics in the Upper Ediacaran coated grain dolostone, Northeast Sichuan Basin, SW China: Implications for reconstruction of the paleoceanic environment

In the Upper Ediacaran Dengying Formation of the Sichuan Basin, the presence of abundant, well-preserved microbial carbonates provides a unique opportunity to study Precambrian paleoceanography and microbial carbonate origins. Particularly, the underexplored coated grain dolostones of this formation, characterized by distinct microbially induced fabrics and intragranular dissolution, offer crucial insights for understanding late Ediacaran microbial mineralization and diagenetic sequences. Utilizing selected typical samples, we conducted detailed petrographic and geochemical analyses, revealing a dynamic interplay between microbial processes and sedimentary dynamics. We observe the coexistence of constructive micrite envelopes with microbially induced fabrics such as clots and laminations, highlighting microbial biomineralization's key role in fabric formation. The sedimentary dynamics critically determines the formation processes of the coated grains: low-energy settings foster grain agglomeration and consolidation through clot precipitation between grains, while high-energy settings favor smaller grains binding to microbial mats. Geochemically, micrite envelopes play an essential role in preserving distinct rare earth element (REE) signatures. The weak negative Ce anomalies and positive Eu anomalies within these envelopes point to a suboxic to anoxic depositional environment, directly indicative of the microenvironmental conditions conducive to microbial mineralization processes. Furthermore, our study sheds light on the structural evolution of coated grains with hollow nuclei, proposing that their internal pore formations are influenced by both mineral instability and selective dissolution by meteoric freshwater. These findings not only provide fresh insights into complex diagenetic processes in the Dengying Formation but also substantially advance our understanding of early microbial life and environmental adaptations during the Precambrian.

Consequential LCA of NPK fertilizers from microbial, animal, plant, and mineral origin highlights resource constraints and environmental impacts

The production and use of mineral fertilizers lead to severe environmental impacts, therefore initiatives such as the European Green Deal promote organic farming and nutrient circularity. However, many organic fertilizers (those containing organic carbon and nutrients of exclusively biological origin) face constraints due to resource availability, and it is paramount to understand their environmental impacts to prevent unforeseen effects. This study employed a consequential life cycle assessment (LCA) to compare the environmental impact of mineral fertilizer to three types of organic fertilizers: animal-, plant-, and innovative microbe-based, considering market constraints and marginal suppliers. Organic fertilizers were complemented with mineral products to yield NPK compound fertilizers containing 1 t of nitrogen, 0.44 t of phosphorus, and 0.83 t of potassium (multi-substance functional unit). The findings reveal that 9 out of the 17 studied organic fertilizers are constained products, and that their demand is met through the supply of mineral fertilizers, soybean meal, and maize or barley grain. Consequently, for the transition to a circular and organic agrifood system, the focus should shift toward untapped resources like microbial fertilizers sourced from food and beverage industry wastewater, and sewage sludge. Constrained markets vary with time and geographical location, emphasizing the importance of context-specific decision-making. The impact of mineral fertilizers is relatively low across impact categories, but the gap between them and energy-intensive organic fertilizers narrows in an industrial symbiosis scenario where waste heat is available. An additional assessment of soil organic carbon estimated the contribution of organic fertilizers to the “4 per 1000" initiative's goal for soil carbon storage. Organic fertilizer application alone only achieves this goal in one scenario (rapeseed meal), but combining it with other management practices like crop rotation offers a promising strategy. The scenario that included fertilizer transport showed the potential for reduced environmental impacts by applying locally available by-products as organic fertilizer instead of imported mineral fertilizers. Overall, the results call for caution when transitioning from mineral to organic fertilizers as their availability and environmental impact are not self-evident.

Development of dye-sensitized solar cells using pigment extracts produced by Talaromyces atroroseus GH2

The identification of more efficient, clean, secure, and competitive energy supply is necessary to align with the needs of sustainable devices. For this reason, a study for developing innovative dye-sensitized solar cells (DSSCs) based on microbial pigments is reported starting from Talaromyces atroroseus GH2. The fungus was cultivated by fermentation and the extracellular pigment extract was characterized by HPLC-DAD-ESI-MS analyses. The most abundant compound among the 22 azaphilone-type pigments identified was represented by PP-O. The device’s behavior was investigated in relation to electrolyte and pH for verifying the stability on time and the photovoltaic performance. Devices obtained were characterized by UV–vis measurements to verify the absorbance intensity and transmittance percentage. Moreover, photovoltaic parameters through photo-electrochemical measurements (I–V curves) and impedance characteristics by Electrochemical Impedance Spectroscopy (EIS) were determined. The best microbial device showed a short-circuit current density (Jsc) of 0.69 mA/cm2, an open-circuit photo-voltage (Voc) of 0.27 V and a Fill Factor (FF) of 0.60. Furthermore, the power conversion efficiency (PCE) of the device was 0.11%. Thus, the present study demonstrated the potential of microbial origin pigments for developing DSSCs.Graphical abstract

Surface and Aggregation Properties of Rhamnolipids in Water–Bioethanol Mixtures: A Step toward Green Formulation Design

Water–ethanol mixtures are largely exploited for many different applications, from industrial processes to pharmaceutical formulations. Surfactants are often added to tune their interfacial properties. Sustainability concerns require redesigning such blends to minimize their environmental impact. A successful approach is to replace synthetic oil-based components with affordable unpurified bio-derived alternatives. In this respect, we have characterized aqueous mixtures of bioethanol, obtained by the fermentation of algae, and rhamnolipids, biosurfactants of microbial origin. The physico-chemical characterization of water–bioethanol binary mixtures in terms of refractive index, density, viscosity, and surface tension indicates that bioethanol behaves like pure ethanol with negligible effects of impurities. Analysis of tensiometric titrations shows that, at bioethanol contents higher than 20–30% bioethanol mass percent, rhamnolipid aggregation is impaired, whereas surface adsorption at the water–air interface remains poorly affected. Overall, bio-derived components can be proposed as a promising alternative to oil-derived chemicals in eco-sustainable formulations.

Microbiological indicators of cottage cheese using different rennet leavens

Rennet cheeses occupy an important place in the diets of the population of Ukraine. The technology of cheese production depends both on the quality of raw materials and on the quality of the enzymes used to curdle milk. Therefore, the study of the effect of rennet enzymes obtained by improved biotechnology on the microbial state of the finished product is of scientific and practical importance. III groups of samples (n = 3) were formed to conduct the experiment. Cow's milk for research was collected from clinically healthy cows during the calving period. In the control group of samples, rennet enzyme of microbial origin was used for curdling milk. In the 1st experimental group of samples, an enzyme preparation was used, extracted from the rennet of dairy calves according to the method of Yu. Ya. Svyridenko In the II experimental group, an enzyme preparation obtained by the method of extraction according to the method of was used. S. V. Merzlova. Laboratory research was carried out in the conditions of the Research Institute of Food Technologies and Technologies of Processing Livestock Products and the Laboratory of Microbiological Research Methods of the Department of Microbiology of the Bilotserk National Agrarian University, which is certified according to (DSTU ISO 10012:2005). To determine the qualitative and quantitative microbial composition, culture was carried out from cheeses obtained with the help of various enzyme preparations. Microbiological research was carried out using the methods defined by DSaNPiN 4.4.5-078-2001 “Microbiological standards and methods of control of food products”. To determine bacterial insemination, two nutrient media such as Lees agar and Streptococcus thermophilus agar were used. The method of serial dilutions was used for seeding the suspension. Sowing was carried out by applying 1.0 cm³ of suspension (dilutions from 1 to 10-5) in melted and cooled agar in Petri dishes, followed by thermostating for 48 hours at 37 °.

Developing Green Sorbents Derived from Natural Materials for Microextraction and Determination of Emerging Contaminants

Developing Green Sorbents Derived from Natural Materials for Microextraction and Determination of Emerging Contaminants

Changes in the composition of the gut microbiota and content of microbial-derived uremic toxins in patients undergoing hemodialysis

Recent data highlight a significant role of the gut microbiota in the pathogenesis of chronic kidney disease, particularly in its terminal stage. However, little is known about the features of intestinal dysbiosis in people undergoing programed hemodialysis. Changes in the intestinal microbiota and blood levels of uremic toxins of microbial origin in patients with terminal renal insufficiency receiving hemodialysis were analyzed. This cross-sectional study included 80 patients receiving hemodialysis and 20 individuals with normal kidney function. The state of the microbiocenosis of the colon was studied using a polymerase chain reaction with a commercial set Colonoflor 16 (premium) manufactured by Alfalab (Russia). Serum levels of trimethylamine and its metabolite trimethylamine-N-oxide were determined by liquid chromatography/mass spectrometry. The concentrations of indoxyl sulfate and p-cresyl sulfate were evaluated by enzyme immunoassay according to the instructions of a commercial kit. In patients undergoing programed hemodialysis, increased colonization of enterococci was combined with the reduction of lacto and bifidophlora, E. coli, ruminococci, bacteria producing short-chain fatty acids (Faecalibacterium prausnitzii, Eubacterium rectale, Roseburia inulinivorans, and Blautia spp.) and microorganisms involved in maintaining the integrity of the intestinal barrier (Bacteroides thetaomicron and Akkermansia muciniphila). In addition, high titer levels of representatives of opportunistic and even pathogenic flora were often found in this group. Intestinal dysbiosis in patients undergoing programed hemodialysis was accompanied by a significant increase in the concentration of uremic toxins in the blood. Compared with individuals with normal renal function, the trimethylamine level in patients undergoing programed hemodialysis was increased 22 times; trimethylamine-N-oxide, 23 times; indoxyl sulfate, 21 times; and p-cresyl sulfate, 5 times. Thus, patients receiving hemodialysis exhibited pronounced pathological changes in intestinal microbiocenosis, accompanied by a significant increase in serum levels of uremic toxins of microbial origin.

Response of heterologously expressed pressure sensor-actuator-modulator macromolecule to external mechanical stress

Cells from different organs in the body experience a range of mechanical and osmotic pressures that change in various diseases, including neurological, cardiovascular, ophthalmological, and renal diseases. Here, we demonstrate the use of an engineered Sensor-Actuator-Modulator (SAM) of microbial origin derived from a mechanosensitive channel of large conductance (MscL) for sensing external mechanical stress and modulating activities of mammalian cells. SAM is reliably expressed in the mammalian cell membrane and acts as a tension-activated pressure release valve. Further, the activities of heterologously expressed SAM in mammalian cells could be modulated by osmotic pressure. A comparison of the mechanosensitive activities of SAM-variants from different microbial origins shows differential inward current and dye uptake in response to mechanical stress exerted by hypo-osmotic shock. The use of SAM channels as mechanical stress-activated modulators in mammalian cells could provide new therapeutic approaches for treating disorders related to mechanical or osmotic pressure.

Microbially conjugated bile salts found in human bile activate the bile salt receptors TGR5 and FXR.

Bile salts of hepatic and microbial origin mediate interorgan cross talk in the gut-liver axis. Here, we assessed whether the newly discovered class of microbial bile salt conjugates (MBSCs) activate the main host bile salt receptors (Takeda G protein-coupled receptor 5 [TGR5] and farnesoid X receptor [FXR]) and enter the human systemic and enterohepatic circulation. N-amidates of (chenodeoxy) cholic acid and leucine, tyrosine, and phenylalanine were synthesized. Receptor activation was studied in cell-free and cell-based assays. MBSCs were quantified in mesenteric and portal blood and bile of patients undergoing pancreatic surgery. MBSCs were activating ligands of TGR5 as evidenced by recruitment of Gsα protein, activation of a cAMP-driven reporter, and diminution of lipopolysaccharide-induced cytokine release from macrophages. Intestine-enriched and liver-enriched FXR isoforms were both activated by MBSCs, provided that a bile salt importer was present. The affinity of MBSCs for TGR5 and FXR was not superior to host-derived bile salt conjugates. Individual MBSCs were generally not detected (ie, < 2.5 nmol/L) in human mesenteric or portal blood, but Leu-variant and Phe-variant were readily measurable in bile, where MBSCs comprised up to 213 ppm of biliary bile salts. MBSCs activate the cell surface receptor TGR5 and the transcription factor FXR and are substrates for intestinal (apical sodium-dependent bile acid transporter) and hepatic (Na+ taurocholate co-transporting protein) transporters. Their entry into the human circulation is, however, nonsubstantial. Given low systemic levels and a surplus of other equipotent bile salt species, the studied MBSCs are unlikely to have an impact on enterohepatic TGR5/FXR signaling in humans. The origin and function of biliary MBSCs remain to be determined.

Purification and Biochemical Characterization of Phytase Enzyme from Lactobacillus brevis Isolated from Fresh Kashar Cheese

In the last 20 years, phytase enzyme has attracted the attention of scientists in the fields of environmental protection, nutrition and biotechnology. Myo-inositol hexaphosphate phosphohydrolase (phytase), which is a type of phosphatase enzyme, catalyzes the hydrolysis of phytate into less phosphorylated inorganic phosphates and phytate. Phytases of microbial origin are widely used in biotechnological applications (paper industry, feed industry, food industry and soil improvement).&#x0D; In the present study, phytase enzyme was partially purified from Lactobacillus brevis NM-34 strain isolated from fresh kashar cheese and the pH and temperature values at which the enzyme showed optimum activity were determined. L. brevis NM-34 showed a phytase activity of 243.80 U/mL as a result of ammonium sulfate precipitation. In the ammonium sulfate range (40-60%), where the highest phytase activity was observed, the protein concentration was measured as 0.989 mg/mL. Km and Vmax values of phytase enzyme were determined as 0.0146 mM and 1.6 µmol/min, respectively. The pH and temperature values at which the partially purified phytase showed optimum activity were found to be pH 5 and 50 °C, respectively. Based on the findings from our research, the enzyme purified from this bacterium was found to have unique properties that make it suitable for use in industrial applications.

Entomopathogenic fungi, Metarhizium anisopliae as a chemical substitute for termite pest management in sugarcane

Aim: The present research study was undertaken to assess the efficacy of microbial and natural origin bio-pesticides in comparison to chemical control against termites infesting sugarcane. Methodology: Field trials were executed for a period of three successive seasons i.e., 2019-20, 2020-21 and 2021-22 at Sugarcane Research Station, Vuyyuru, Krishna district, Andhra Pradesh. The experiment was laid out in randomized block design with seven treatments replicated thrice and imposed the treatments as per protocol. A set of four bio-pesticides (Beauveria bassiana, Metarhizium anisopliae, Bacillus thuringiensis and Azadirachtin) and two insecticides (Imidacloprid and Bifenthrin) were evaluated for their efficacy against termite infestation in terms of both mean number of sugarcane setts infested and mean portion of setts infested by termites. Results: The chemicals imidacloprid and bifenthrin had registered highest per cent reduction of termite infestation over control. However, the biopesticides, Metarhizium anisopliae had registered least per cent reduction of mean number of setts infested with 59.95 at 60 DAP, 62.85 at 90 DAP and 56.03 at 120 DAP and mean portion of setts infested with termite was 56.20 per cent. With respect to yield also the chemical treatments viz., imidacloprid and bifenthrin had recorded higher yields with pooled mean of 77.33 and 76.78 t ha-1, followed by M. anisopliae with 73.94 t ha-1. Interpretation: Even though the chemical based treatments were found superior in reducing termite infestation, entomopathogenic fungi, M. anisopliae as biopesticide also attributed better results with regard to suppression of termite infestation and can be suggested as alternative or substitution to chemical based management. Key words: Chemical control, Entomopathogenic fungi, Metarhizium, Sugarcane, Termites

Effect of long-term compost fertilization on the distribution of organic carbon and nitrogen in soil aggregates

Soil fertility is mainly related to soil total organic carbon (C) that should be preserved in order to optimize soil quality and functionality. Consequently, the use of organic amendments could be a possible strategy to increase soil C and nitrogen (N) storage particularly in orchard systems where the disturbance of soil is reduced thus making favorable conditions for C and N stabilization.The aim of this study was to evaluate the distribution and stabilization of organic C and total N in aggregate fractions after a 14-years-period of compost application to a peach orchard. The trial was conducted in the south-eastern Po valley, on a commercial nectarine orchard and the following treatments were compared in a complete randomized block design with four replicates: 1. unfertilized control; 2. mineral fertilization; 3. compost at a rate of 10 Mg dry weight ha−1 yr−1. At the end of orchard lifetime, soil was sampled from the row at four depths (0–0.15, 0.16–0.25, 0.26–0.45, and 0.46–0.65 m) and physically fractionated to separate macroaggregates (> 250 μm), microaggregates (250–50 μm) and silt and clay (< 50 μm) that were analyzed for organic C, total N, δ13C, and δ15N.Compost addition induced a significant increase of macroaggregates (66%), no changes in microaggregates and a decrease of silt and clay (22%) compared to control and mineral fertilization. With compost the accumulation of organic C and total N content in the macroaggregates was four-five times higher than the other two treatments in all the depths, therefore almost 50% of the soil organic C was in this fraction, compared to 20–24% in the control and mineral. In the micro-aggregates more C and N accumulated only in the two top layers, while no effect was observed in the silt and clay fraction. From macro-to microaggregates to the silt and clay fraction, the C/N ratio shifted from 9 to 7.5 to 6 on average indicating that the C and N stabilized in the finer fractions is mainly of microbial origin. The enrichment in C and N isotopic composition from macro-to micro to silt and clay is also indicative of the isotopic fractionation due to microbial metabolism and the consequent stabilization of microbial residues in the finer fractions. In the control and mineral, only receiving orchard litter, this change was observed in all the layers, on the contrary, with compost similar δ13C and δ15N values characterized the fractions in the top soil layer suggesting the occlusion of compost in all the fraction. With depth the macroaggregates maintained the same δ13C and δ15N values indicating consistent redistribution of compost in deep soil layers, while the finest fractions showed a progressive enrichment of δ13C due to the presence of C fractionated during microbial metabolism and progressively stabilized. In conclusion, compost supply leads to positive effects on C and N accumulation and stabilization also in the deeper layers favoring the increase of long-term soil fertility and C storage.

Degree of awareness and practices on urinary tract infections: A study of Sri Lankan school teachers selected from a chronic kidney disease high-prevalent setting.

As key stakeholders in educational settings, teachers' awareness on Urinary Tract Infections (UTI) will ultimately enhance its management in schools and community. This study aimed to assess the level of knowledge, attitudes, and practices (KAP) on UTIs among teachers in Sri Lanka. Conveniently selected 373 school teachers were assessed using a pre-tested questionnaire. Each of the individual was scored and categorized as either satisfactory or poor. Descriptive statistics and chi-square tests were performed to describe the outcomes. Around 80% of respondents demonstrated awareness regarding the microbial origin of UTIs, while 42% possessed knowledge of women's increased susceptibility to UTIs. Over 90% of participants had favorable attitudes toward drinking adequate amounts of water, personal hygiene, and consulting doctors for UTI symptoms. Each inquiry demonstrated significant disparities between individuals with satisfactory and poor attitudes (p = 0.000), with over 95% adhered to effective hygiene practices as a preventive measure against UTIs. The demographics of the participants did not show any significance over the KAP results of the study (p < 0.05). The study revealed satisfactory levels of awareness and favorable attitudes among respondents on UTIs. However, there is a further need for increased awareness, specifically regarding the risk factors associated with UTIs.

Engineered Saccharomyces cerevisiae as a Biosynthetic Platform of Nucleotide Sugars.

Glycosylation of biomolecules can greatly alter their physicochemical properties, cellular recognition, subcellular localization, and immunogenicity. Glycosylation reactions rely on the stepwise addition of sugars using nucleotide diphosphate (NDP)-sugars. Making these substrates readily available will greatly accelerate the characterization of new glycosylation reactions, elucidation of their underlying regulation mechanisms, and production of glycosylated molecules. In this work, we engineered Saccharomyces cerevisiae to heterologously express nucleotide sugar synthases to access a wide variety of uridine diphosphate (UDP)-sugars from simple starting materials (i.e., glucose and galactose). Specifically, activated glucose, uridine diphosphate d-glucose (UDP-d-Glc), can be converted to UDP-d-glucuronic acid (UDP-d-GlcA), UDP-d-xylose (UDP-d-Xyl), UDP-d-apiose (UDP-d-Api), UDP-d-fucose (UDP-d-Fuc), UDP-l-rhamnose (UDP-l-Rha), UDP-l-arabinopyranose (UDP-l-Arap), and UDP-l-arabinofuranose (UDP-l-Araf) using the corresponding nucleotide sugar synthases of plant and microbial origins. We also expressed genes encoding the salvage pathway to directly activate free sugars to achieve the biosynthesis of UDP-l-Arap and UDP-l-Araf. We observed strong inhibition of UDP-d-Glc 6-dehydrogenase (UGD) by the downstream product UDP-d-Xyl, which we circumvented using an induction system (Tet-On) to delay the production of UDP-d-Xyl to maintain the upstream UDP-sugar pool. Finally, we performed a time-course study using strains containing the biosynthetic pathways to produce five non-native UDP-sugars to elucidate their time-dependent interconversion and the role of UDP-d-Xyl in regulating UDP-sugar metabolism. These engineered yeast strains are a robust platform to (i) functionally characterize sugar synthases in vivo, (ii) biosynthesize a diverse selection of UDP-sugars, (iii) examine the regulation of intracellular UDP-sugar interconversions, and (iv) produce glycosylated secondary metabolites and proteins.

Early Triassic (Griesbachian) spheroids in Beibei, Chongqing, Southwestern China: Characteristics, cause and implications for palaeo‐oceanic conditions

Following the latest Permian mass extinction (LPME), abundant unusual sedimentary features and fabrics were widely distributed in Early Triassic carbonate platforms. As a unique type of carbonate grain, spheroids from the Lower Triassic are infrequently reported, yet differ significantly from giant ooids and oncoids. Griesbachian micritic spheroids are well preserved in the Lower Triassic Feixianguan Formation at the Baimiaozi (BMZ) outcrop in Beibei, Chongqing, southwestern China. These spheroids (diameter: 3.9–10.8 mm) were in a marl layer interbedded with massive oolites. They were deposited in the wave troughs of ripple marks comprising micritic clots, sparry calcite, clay minerals, organic matter and pyrite. A microbial spheroid origin is implied based on the coccoidal microbes (coccoid‐like microspherules and bacterial clump‐like microspherules), numerous pyrite framboids (indications suggest the presence of many sulphate‐reducing bacteria and the high iron content in seawater can promote nitrogen‐fixing cyanobacteria proliferation) and microbial‐derived microspherules. The dark‐coloured matrix between the spheroids primarily included microcrystalline calcite, clay minerals, organic matter and metazoan fossils. The spherical and ellipsoidal shapes of the spheroids suggested rapid accretion and lithification. As a unique carbonate depositional mode, Greisbachian spheroids may have been recorded for a palaeo‐ocean with dysoxic and calcium carbonate supersaturation shortly after the LPME.

Exploring fungal bioemulsifiers: insights into chemical composition, microbial sources, and cross-field applications.

The demand for emulsion-based products is crucial for economic development and societal well-being, spanning diverse industries such as food, cosmetics, pharmaceuticals, and oil extraction. Formulating these products relies on emulsifiers, a distinct class of surfactants. However, many conventional emulsifiers are derived from petrochemicals or synthetic sources, posing potential environmental and human health risks. In this context, fungal bioemulsifiers emerge as a compelling and sustainable alternative, demonstrating superior performance, enhanced biodegradability, and safety for human consumption. From this perspective, the present work provides the first comprehensive review of fungal bioemulsifiers, categorizing them based on their chemical nature and microbial origin. This includes polysaccharides, proteins, glycoproteins, polymeric glycolipids, and carbohydrate-lipid-protein complexes. Examples of particular interest are scleroglucan, a polysaccharide produced by Sclerotium rolfsii, and mannoproteins present in the cell walls of various yeasts, including Saccharomyces cerevisiae. Furthermore, this study examines the feasibility of incorporating fungal bioemulsifiers in the food and oil industries and their potential role in bioremediation events for oil-polluted marine environments. Finally, this exploration encourages further research on fungal bioemulsifier bioprospecting, with far-reaching implications for advancing sustainable and eco-friendly practices across various industrial sectors.

Physiological and molecular insights into the allelopathic effects on agroecosystems under changing environmental conditions.

Allelopathy is a natural phenomenon of competing and interfering with other plants or microbial growth by synthesizing and releasing the bioactive compounds of plant or microbial origin known as allelochemicals. This is a sub-discipline of chemical ecology concerned with the effects of bioactive compounds produced by plants or microorganisms on the growth, development and distribution of other plants and microorganisms in natural communities or agricultural systems. Allelochemicals have a direct or indirect harmful effect on one plant by others, especially on the development, survivability, growth, and reproduction of species through the production of chemical inhibitors released into the environment. Cultivation systems that take advantage of allelopathic plants' stimulatory/inhibitory effects on plant growth and development while avoiding allelopathic autotoxicity is critical for long-term agricultural development. Allelopathy is one element that defines plant relationships and is involved in weed management, crop protection, and microbial contact. Besides, the allelopathic phenomenon has also been reported in the forest ecosystem; however, its presence depends on the forest type and the surrounding environment. In the present article, major aspects addressed are (1) literature review on the impacts of allelopathy in agroecosystems and underpinning the research gaps, (2) chemical, physiological, and ecological mechanisms of allelopathy, (3) genetic manipulations, plant defense, economic benefits, fate, prospects and challenges of allelopathy. The literature search and consolidation efforts in this article shall pave the way for future research on the potential application of allelopathic interactions across various ecosystems.