Small Spores Research Articles

The Investigation of Comparative Spore Morphologies of Acrocarpous and Pleurocarpous Two Mosses (Bryophyta)

Bryophyta members in the subkingdom Bryobiotina are distributed in a wide variety of habitats. Mosses are morphologically divided into two large groups: acrocarpous and pleurocarpous. Acrocarpic species have arid character and pleurocarpic species are distributed in more moist regions. The spores of the pleurocarpous Brachythecium salebrosum (Hoffm. ex F. Weber & D. Mohr) Schimp. and the acrocarpous Crossidium squamiferum var. pottioideum (De Not.) Mönk. were examined in comparison in this study. Spore slides were prepared using both Erdtman (acetolysis) and Wodehouse methods and examined under a light microscope (LM). As a result of the analyses, it was found that the spores of C. squamiferum var. pottioideum were oblate in both methods, while the spores of B. salebrosum were suboblate in the acetolysis method and oblate in the Wodehouse method. Spores of both taxa are classified as small spores. Furthermore, the equatorial axis is longer than the polar axis in the spores of both taxa and the thicknesses of the intine layer of the spores are almost identical at 0.50 µm (B. salebrosum) and 0.53 µm (C. squamiferum var. pottioideum). In addition, the thickness of the sclerine of B. salebrosum spores was about 0.70 µm in both methods, while it was 0.56 µm in acetolysed spores of C. squamiferum var. pottioideum and 0.78 µm in Wodehouse treated spores. Both taxa have monolete and trilete spores. On the other hand, SEM examinations revealed that B. salebrosum has gemmate ornamentation, while C. squamiferum var. pottioideum has verrucate ornamentation. The findings obtained as a result of the studies helped to reveal the differences between the spores of taxa in different morphological groups and brought a different perspective in their ecological evaluation.

Molecular and morphological evidence for a new seed-destroying smut fungus, Microbotryum graecum on Stellaria media from Greece

The group of seed-destroying Microbotryum species on caryophyllaceous hosts includes ten species, among which only M. alsines, on Stellaria nitens from USA, is known on Stellaria. Recently, a specimen of Stellaria media from Greece, infected by a seed-destroying Microbotryum species, was found in a phanerogam herbarium. Based on distinct morphology and phylogenetic evidence, this fungus was considered to represent an unknown species which is described and illustrated as Microbotryum graecum. It can be distinguished from M. alsines by having smaller spores, fewer meshes per spore diameter, a different spore ornamentation, wider meshes, and higher spore wall muri.

Burning Frequency Influences Plant Composition and Diversity and Mycorrhizal Spore Density in a Lateritic Dry Deciduous Sal Dominated Forest

Abstract: Burning in forest floor, specially, in deciduous forests is an annual practice of forest dwellers in some states of India to collect non timber forest produce at ease. Sometimes this springtime burning get out of control and damage the forest severely. Sal dominated mixed forest in Godapyasal range, Midnapore division, West Midnapore in south West Bengal, with different fire incidence histories was taken for the study. An intensive survey of sites with regular burning, occasional burning and no burning were done to study plant diversity and community composition and the results were compared within different sites. Severe burning regimes damaged the plant density drastically rendering the saplings of subdominants only near ground level as coppice. Mild fire frequencies, though not severely damaged plant community, differed from unburned area significantly. Fire hardy tree species are dominant and subdominant in both sites. In severe burned site, plant diversity increased with a number of invasive perennials and annuals and spiny undershrubs and show even distribution. Common plants in the three communities were observed to be affected in their community parameters with burning frequency. Frequent and occasional burning both reduced mycorrhizal population with larger spores drastically and not replaced even after nine months of burning. AMF with smaller spores are less affected.

Detection of cucumber downy mildew spores based on improved YOLOv5s

Cucumber downy mildew is caused by the infection of leaves with downy mildew spores. However, research on the prevention and control of cucumber downy mildew often focuses on the stage after symptoms have appeared on the leaves, that is, once disease spots have already formed. Since the occurrence of downy mildew is closely related to the quantity of spores, early-stage research on the quantity of downy mildew spores is of great significance for the prevention and control of cucumber downy mildew. Consequently, developing a rapid, accurate, and efficient method for detecting cucumber downy mildew spores is critical for advancing disease control. This study introduces an improved YOLOv5s model for spore detection. The model incorporates a transformer module into YOLOv5s’s backbone, enhancing global feature information extraction. It also adds a small object detection head to counter YOLOv5s’s extensive down-sampling and difficulty in learning features of small objects. Integration with the Convolutional Block Attention Module (CBAM) further refines detection precision for small objects like mildew spores. Upon evaluation with an image dataset collected through a microscope, the improved YOLOv5s model demonstrated superior performance metrics across various resolutions. At a resolution of 1440px × 1440px, it achieved the highest mean Average Precision (mAP@.5) of 95.4 %, a precision (P) score of 89.1 %, and a recall (R) rate of 90.3 %. These metrics surpassed the original YOLOv5s model at the same 1440px × 1440px resolution by 1.6 % in mAP@.5, 1.6 % in P, and 0.5 % in R. Additionally, the model’s mAP@.5 across various resolution scales indicates superior detection precision compared to other leading models like YOLOv7. In the context of microscopic images with small spores and complex backgrounds, the improved YOLOv5s model effectively detects cucumber downy mildew spores, offering valuable insights and technical support for advancing the prevention and control measures against cucumber downy mildew.

The Use of the Internal Transcribed Spacer Region for Phylogenetic Analysis of the Microsporidian Parasite Enterocytozoon hepatopenaei Infecting Whiteleg Shrimp (Penaeus vannamei) and for the Development of a Nested PCR as Its Diagnostic Tool.

The increasing economic losses associated with growth retardation caused by Enterocytozoon hepatopenaei (EHP), a microsporidian parasite infecting penaeid shrimp, require effective monitoring. The internal transcribed spacer (ITS)-1 region, the non-coding region of ribosomal clusters between 18S and 5.8S rRNA genes, is widely used in phylogenetic studies due to its high variability. In this study, the ITS-1 region sequence (~600-bp) of EHP was first identified, and primers for a polymerase chain reaction (PCR) assay targeting that sequence were designed. A newly developed nested-PCR method successfully detected the EHP in various shrimp (Penaeus vannamei and P. monodon) and related samples, including water and feces collected from Indonesia, Thailand, South Korea, India, and Malaysia. The primers did not cross-react with other hosts and pathogens, and this PCR assay is more sensitive than existing PCR detection methods targeting the small subunit ribosomal RNA (SSU rRNA) and spore wall protein (SWP) genes. Phylogenetic analysis based on the ITS-1 sequences indicated that the Indonesian strain was distinct (86.2% nucleotide sequence identity) from other strains collected from Thailand and South Korea, and also showed the internal diversity among Thailand (N = 7, divided into four branches) and South Korean (N = 5, divided into two branches) samples. The results revealed the ability of the ITS-1 region to determine the genetic diversity of EHP from different geographical origins.

The use of the internal transcribed spacer region for phylogenetic analysis of the microsporidian parasite Enterocytozoon hepatopenaei infecting whiteleg shrimp (Penaeus vannamei) and for the development of a nested PCR as its diagnostic tool.

The increasing economic losses associated with growth retardation caused by Enterocytozoon hepatopenaei (EHP), a microsporidian parasite infecting penaeid shrimp, require effective monitoring. The internal transcribed spacer (ITS)-1 region, the non-coding region of ribosomal clusters between 18S and 5.8S rRNA genes, is widely used in phylogenetic studies due to its high variability. In this study, the ITS-1 region sequence (~600-bp) of EHP was first identified, and primers for a polymerase chain reaction (PCR) assay targeting that sequence were designed. A newly developed nested-PCR method successfully detected the EHP in various shrimp (Penaeus vannamei and P. monodon) and related samples, including water and feces collected from Indonesia, Thailand, South Korea, India, and Malaysia. The primers did not cross-react with other hosts and pathogens, and this PCR assay is more sensitive than existing PCR detection methods targeting the small subunit ribosomal RNA (SSU rRNA) and spore wall protein (SWP) genes. Phylogenetic analysis based on the ITS-1 sequences indicated that the Indonesian strain was distinct (86.2%) from other strains collected from Thailand and South Korea, and also showed the internal diversity among Thailand (N = 7, divided into four branches) and South Korean (N = 5, divided into two branches) samples. The results revealed the ability of the ITS-1 region to determine the genetic diversity of EHP from different geographical origins.

Introducing Russula subgen. Cremeo-ochraceae, a new and very small lineage sharing with Multifurca (Russulaceae) an identical, largely circum-Pacific distribution pattern

The application of DNA data on a worldwide sampling has revolutionized the infrageneric classification of the highly diverse ectomycorrhizal genus Russula. Based on collections made in New Zealand, East Asia and North America,this study describes a new subgenus Cremeo-ochraceae, the ninth subgenus of Russula. Even though BLASTn of the ITSsequences suggested affinities with species of subgenera Russula and Heterophyllidiae, the phylogenetic analysis based on a five-locus DNA dataset placed the target samples in an independent major clade that is taxonomically equivalent to subgenus. This multilocus analysis also obtained support for the recognition of two superclades in Russula, opposing subgenera Glutinosae, Archaeae and Compactae to the rest of the genus. The type species of the new subgenus is R. cremeo-ochracea from New Zealand, which is here epitypified, and the authors describe a new variety for it: R. cremeoochraceavar. myrtacearum. The new subgenus also harbors a North American R. cf. inopina and its Asian counterpart,discovered from southwestern China, described here as R. estriata sp. nov. Two environmental ITS sequences, onefrom Japan and one from Malaysia may represent two more undescribed taxa. The new subgenus shares with subgen.Brevipedum subsect. Pallidosporinae the general field habit, the unequal lamellae and the relatively small spores with inamyloid suprahilar spot and similar spore ornamentation. It differs from the latter subsection principally in the poorcontents of all types of cystidioid cells and the often areolate-scurfy pileus surface composed of slender, undulating hyphal terminations with frequent subcapitate apices. Biogeographically, subgen. Cremeo-ochraceae shares with Multifurca, another small relict lineage of Russulaceae, a circum-Pacific distribution pattern except for South America. Both lineages lack representatives in Europe and Africa. The hypothesis proposing an African origin for the genus is considered unlikely.

Mycena fragosa (Mycenaceae), a new species from the fragas in northwestern Spain

A new species of Mycena from northwestern Spain is described, illustrated and morphologically and molecularly compared to related species. The new species belongs to M. sect. Viscipelles, presenting as tiny in stature, with small spores, claviform to subglobose cheilocystidia with short excrescences, and a small disc at the base of the stipe, which is made up of long cystidia. Currently, it has been only found at three localities of Atlantic forest, where it grows on dead leaves of Alnus lusitanica, Acer pseudoplatanus, Salix atrocinerea, and Quercus robur acorn cupules. In addition, a key to the taxa of M. sect. Viscipelles, which are known in the Northern Hemisphere, is provided

Two new species of smut fungi from the Neotropics: Ustanciosporium bulbostylidis-truncatae and Ustanciosporium bulbostylidis-coniferae

Two new species of Ustanciosporium, U. bulbostylidis-truncatae and U. bulbostylidis-coniferae, are described and illustrated. These are the first records of species of this genus on hosts in Bulbostylis (Cyperaceae). Both species are known only from their type localities, in the savannas of Suriname (Sipaliwini Savanna Nature Reserve, for U. bulbostylidis-truncatae) and Guyana (near Manari, for U. bulbostylidis-coniferae). Ustanciosporium bulbostylidis-truncatae is distinguished from U. bulbostylidis-coniferae by having smaller spores, (9.5–)10–12.5(–13.5) μm long vs. (12–)12.5–15.5(–16.5) μm long for U. bulbostylidis-coniferae, and thinner spore wall, 0.5–0.9(–1.2) μm thick vs. 0.6–1.7(–2.0) μm thick for U. bulbostylidis-coniferae.

Hydnum pallidum Raddi, the Correct Name for H. albidum Peck in the Sense of European Authors and the Recently Described H. reginae Kibby, Liimat. & Niskanen.

The systematics of the genus Hydnum have undergone important advances, and many new species have been described with the aid of molecular data. A revision of old names that refer to Hydnum s. str., considering the knowledge now available, might reveal prioritary names of recently described species. This study focuses on the study of names that refer to white Hydnum in Europe, among which earlier synonyms of Hydnum reginae (=Hydnum albidum s. auct. pl. eur.) are potentially found, a species characterized by producing white basidiomata and smaller spores than any other European species. Our revision revealed the existence of three earlier names based on European material, namely H. pallidum Raddi, H. album Fr. and H. heimii Maas Geest. The earliest of those, Hydnum pallidum, is epitypified using material from Tuscany (Italy), from where it was originally described, and hence, it becomes the correct name for H. albidum s. auct. pl. eur. A full description and photographs of H. pallidum are provided, and further comments on other names that refer to white Hydnum based on European material are made.

Two new species of Cyclocybe (Agaricales, Tubariaceae) from China

Cyclocybe encompasses 12 species which are distributed worldwide. In this study, two new species named C. suberebia and C. dinggyensis are introduced from China. Phylogenetic analyses based on nrITS, nrLSU, tef1-α, and rpb2 data show their placement within Cyclocybe in two distinct lineages. Cyclocybe suberebia is characterized by its dark brown to light brown pileus, smaller spore size, clampless hyphae. Cyclocybe dinggyensis is characterized by a slender basidioma, tetrasporic basidia and clampless hyphae. Descriptions, colour photographs and line drawings of both new species are presented.

Proteomics-based analysis of the stress response of Bacillus cereus spores under ultrasound and electrolyzed water treatment

Ultrasound is a green nonthermal technology with promising applications in microbial inactivation. Electrolyzed water has been investigated and found to have a synergistic inactivation effect of ultrasound on spores. This study used a data-independent-acquisition method to analyze the stress response of Bacillus cereus spores following ultrasound combined with electrolyzed water treatment. We identified 197 differentially expressed proteins under ultrasound combined with an electrolyzed water treatment for which the ratio in the metabolic pathway was the highest. Spores downregulated key proteins in energy metabolic and transportation pathways, in particular in phosphotransferase systems and ATP synthase under ultrasound, electrolyzed water, and combined stress. The results of this study revealed that the key proteins in intracellular metabolism decreased after ultrasound treatment, and the expression of small acid-soluble spore protein and cell wall biosynthesis protein increased. Meanwhile, DNA integration, recombination, and inversion protein and small acid-soluble spore protein were upregulated after electrolyzed water treatment. In general, the spores exhibited stress resistance under external stress. The inactivation of spores by further stress was reduced, which we called “cross-protection.”

Altitudinal Gradient and Soil Depth as Sources of Variations in Fungal Communities Revealed by Culture-Dependent and Culture-Independent Methods in the Negev Desert, Israel.

We examined fungal communities in soil profiles of 0-10 cm depth along the altitudinal gradient of 250-530-990 m.a.s.l. at the Central Negev Desert, Israel, which benefit from similar annual precipitation (95 mm). In the soil samples collected in the summer of 2020, a mycobiota accounting for 169 species was revealed by both culture-dependent and culture-independent (DNA-based) methodologies. The impact of soil depth on the variations in fungal communities was stronger than the impact of altitude. Both methodologies displayed a similar tendency in the composition of fungal communities: the prevalence of melanin-containing species with many-celled large spores (mainly Alternaria spp.) in the uppermost layers and the depth-wise increase in the proportion of light-colored species producing a high amount of small one-celled spores. The culturable and the DNA-based fungal communities had only 13 species in common. The differences were attributed to the pros and cons of each method. Nevertheless, despite the drawbacks, the employment of both methodologies has an advantage in providing a more comprehensive picture of fungal diversity in soils.

First Report of Diaporthe fusicola Causing Postharvest Fruit Rot of Peach (Prunus persica) in China.

In May 2022, rot symptoms were observed on postharvest peach (Prunus persica [L.] Batsch) fruits in a market in Nanchang, Jiangxi province (28°44' N; 115°50' E), China. A total of 80 samples were collected from three different fruit stalls through the market survey. The incidence of this disease was 10 to 15%, and severity varies from approximately 30 to 50% of fruit surface coverage. The symptom of infected fruits was circular, pale brown to brown, rotten, necrotic lesions, covered with white hyphae and small spore masses. Eight symptomatic peach fruits were surface disinfected with 75% ethanol for 30 sec and incisions were made with a sterile scalpel. Small pieces from symptomatic tissues were placed on a potato dextrose agar (PDA) medium and incubated at 25℃ for 7 days. Six isolates were obtained in total. Colonies on PDA were initially white, aerial, fluffy at first, and darkened with age. Alpha conidia were fusoid, hyaline, aseptate, guttulate, tapering towards ends, and ranged in size from 9.8 to 5.1 µm × 3.2 to 2.1 µm (x ̅=7.1 ± 1.0 × 2.6 ± 0.3 µm, n=60). Beta conidia were not seen. For further confirmation, genomic DNA was extracted from three isolates (04-10, 04-11, and 04-12), the internal transcribed spacer (ITS) region, beta-tubulin (TUB), calmodulin (CAL), partial translation elongation factor 1-alpha (TEF1-α) and histone H3 (HIS) genes were amplified by using primers ITS1/ITS4, Bt2a/Bt2b, CAL228F/CAL737R, EF1-728F/EF1-986R, CYLH3F/H3-1b (Udayanga et al. 2015), respectively. Sequences were deposited in GenBank (Accession Nos. ON994257 to ON994259 for ITS, OP076824 to OP076826 for TUB, OP076827 to OP076829 for CAL, OP076821 to OP076823 for TEF1-α, OP076830 to OP076832 for HIS). BLAST results showed that ITS and TEF1-α have 99.8% pairwise identity to Diaporthe fusicola (MN816432, KF576256), and the TUB, CAL, and HIS sequences also have 100% pairwise identity to D. fusicola (KF576287, MT978147, MT978142). Phylogenetic analyses of concatenated sequences using Bayesian inference and the maximum likelihood confirmed the identity. To verify Koch's postulates, the pathogenicity of three isolates was tested on harvested healthy peach fruits. Five surface-sterilized fruits were wounded by a sterile scalpel and inoculated with 5-mm-diameter mycelial plugs from 10-day-old PDA plates. Another set of five fruits was inoculated with sterilized PDA plugs as controls. All fruits were incubated at 26℃ with 80% relative humidity. The experiment was repeated three times. After 5 days, the fruit inoculated with mycelial plugs showed pale brown lesions with whitish mycelium mass, similar to the previous rot symptoms, whereas the control fruit remained symptomless. The same pathogen was reisolated from the inoculated fruit with symptoms and identified as D. fusicola by molecular techniques, but never from the control. Diaporthe fusicola (Diaporthe amygdali complex) was first described on leaves of Lithocarpus glabra in China (Gao et al. 2015) and reported as an agent causing leaf blotch on Osmanthus fragrans (Si et al. 2020) and pear shoot canker (Guo et al. 2020). However, this is the first report of D. fusicola causing postharvest fruit rot on peach. The managers involved must consider the impact of this disease and develop an effective fruit storage strategy.

New Species of Entoloma Subgenera Cubospora and Leptonia (Agaricales, Basidiomycota) from Central Vietnam.

Four new species of Entoloma from Kon Chu Rang Nature Reserve and Ta Dung National Park were discovered during an investigation of the diversity of the mycobiota of Central Vietnam and are described here on the base of the molecular and morphological data. Phylogenetic analysis was based on nrITS1-5.8S-ITS2, nrLSU and tef1α regions. Illustrated descriptions of their macro- and microscopic features and discussion on similar taxa are given. Entoloma cycneum and E. peristerinum belong to the subgenus Cubospora. They are morphologically similar species and are characterized by white or whitish basidiomata with yellowish or beige tinges and with mainly smooth, glabrous, and hygrophanous pileus, longitudinally fibrillose or fibrillose-scaly white stipe, cuboid spores, and more or less cylindrical cheilocystidia, arising from hymenophoral trama. Entoloma peristerinum posseses initially more coloured beige conical pileus, discolouring to white with age and drying. The pileus of E. cycneum is initially white, hemisphaerical to convex, usually with thin pubescence near the margin. The species can be recognized also by the cheilocystidia form: serrulatum-type in E. cycneum vs. porphyrogriseum-type in E. peristerinum. Another two species belong to the subgenus Leptonia. Entoloma tadungense is close to E. percoelestinum from which it differs by smaller spores with pronounced angles, presence of the cheilocystidia, and the lilac discolouration of the stipe. E. dichroides is named after its similarity to E. dichroum, a dark blue coloured species with pronouncedly angled basidiospores. It is distinguished by the basidiospores form-irregularly 5(-6) angled with elongated apiculus, as well as by absence of the cheilocystidia and darker basidiomata with conical pileus. The article also describes the history of the study of the genus Entoloma in Vietnam with a list of 29 species mentioned in the publications for this country.

Lyophyllum deqinense (Lyophyllaceae, Agaricales), a new species from southwestern China

Lyophyllum deqinense sp. nov. is described and illustrated from Yunnan Province, China, based on morphological features and molecular (ITS and LSU) data. The species can be distinguished by a greyish brown to light brown pileus and obtuse central umbo of the pileus, inrolled margin, globose to subglobose basidiospores (5.7–7.2 × 5.5–6.8 µm), clavate basidia (24–34 × 7–10 µm), cespitose and gregarious habit in soil. L. pallidofumosum is similar to the new species in pileus and stipe color, and shape and size of the basidia, but it lacks an obtuse central umbo, has smaller spores (4.5–5.6 × 4.3–5.4 µm), and sometimes is solitary or subcespitose. The combination of morphological characteristics and phylogenetic analyses indicates that the species belongs to the L. decastes complex.

Structure of Microbial Communities and Biological Activity in Tundra Soils of the Euro-Arctic Region (Rybachy Peninsula, Russia).

The relevance of the Arctic regions' study is rapidly increasing due to the sensitive response of fragile ecosystems to climate change and anthropogenic pressure. The microbiome is an important component that determines the soils' functioning and an indicator of changes occurring in ecosystems. Rybachy Peninsula is the northernmost part of the continental European Russia and is almost completely surrounded by Barents Sea water. For the first time, the microbial communities of the Entic Podzol, Albic Podzol, Rheic Histosol and Folic Histosol as well as anthropogenically disturbed soils (chemical pollution and human impact, growing crops) on the Rybachy Peninsula were characterized using plating and fluorescence microscopy methods, in parallel with the enzymatic activity of soils. The amount and structure of soil microbial biomass, such as the total biomass of fungi and prokaryote, the length and diameter of fungal and actinomycete mycelium, the proportion of spores and mycelium in the fungal biomass, the number of spores and prokaryotic cells, the proportion of small and large fungal spores and their morphology were determined. In the soils of the peninsula, the fungal biomass varied from 0.121 to 0.669 mg/g soil. The biomass of prokaryotes in soils ranged from 9.22 to 55.45 μg/g of soil. Fungi predominated, the proportion of which in the total microbial biomass varied from 78.5 to 97.7%. The number of culturable microfungi ranged from 0.53 to 13.93 × 103 CFU/g in the topsoil horizons, with a maximum in Entic Podzol and Albic Podzol soils and a minimum in anthropogenically disturbed soil. The number of culturable copiotrophic bacteria varied from 41.8 × 103 cells/g in a cryogenic spot to 5551.3 × 103 cells /g in anthropogenically disturbed soils. The number of culturable oligotrophic bacteria ranged from 77.9 to 12,059.6 × 103 cells/g. Changes in natural soils because of anthropogenic impact and a change in vegetation types have led to a change in the structure of the community of soil microorganisms. Investigated tundra soils had high enzymatic activity in native and anthropogenic conditions. The β-glucosidase and urease activity were comparable or even higher than in the soils of more southern natural zone, and the activity of dehydrogenase was 2-5 times lower. Thus, despite the subarctic climatic conditions, local soils have a significant biological activity upon which the productivity of ecosystems largely depends. The soils of the Rybachy Peninsula have a powerful enzyme pool due to the high adaptive potential of soil microorganisms to the extreme conditions of the Arctic, which allows them to perform their functions even under conditions of anthropogenic interference.

Stages of Microspore Development in Eggplant (Solanum melongena L.)

Background: Microspores are small haploid spores that develop into the male gametophyte. Microsporocytes undergo meiotic division to form microspores. Microspores can be found in seedless and seed plants. The microspores in each flowering plant are different. This study aims to observe microspores on eggplant flowers. Method: Microspore observations were carried out on different flower bud sizes until the flower buds bloomed. Result: The results showed microspores in eggplant had different stages of development for each flower bud size. The stages of microspore development observed were Early uninucleate (Young microspore), Mid-uninucleate, Late uninucleate (Vacuolate microspore), early binucleate (Young bicellular pollen), mid-binucleate, and mature pollen. Conclusion: In eggplant microspore culture, anther length is a strong parameter to predict the stage of microspore development contained there in.

New dark species of Cribraria (Myxomycetes) from wetland ecosystem in Tatarstan (Russia)

Fruiting bodies of a grey-coloured Cribraria were found in moist chambers on dead wood of Salix from a wetland ecosystem in Kazan (Tatarstan, Russia). Morphological analysis showed that the species, described as Cribraria gothica, probably belongs to a group with C. tenella and C. languescens, but differs in many respects. Most vivid factors are plumbeous colour of sporocysts, small grey spores and creamy-coloured top of stalk. The comparative characteristic and a key to these related species are given.

New Thoughts on an Old Topic: Secrets of Bacterial Spore Resistance Slowly Being Revealed.

The quest for bacterial survival is exemplified by spores formed by some Firmicutes members. They turn up everywhere one looks, and their ubiquity reflects adaptations to the stresses bacteria face. Spores are impactful in public health, food safety, and biowarfare. Heat resistance is the hallmark of spores and is countered principally by a mineralized gel-like protoplast, termed the spore core, with reduced water which minimizes macromolecular movement/denaturation/aggregation. Dry heat, however, introduces mutations into spore DNA. Spores have countermeasures to extreme conditions that are multifactorial, but the fact that spore DNA is in a crystalline-like nucleoid in the spore core, likely due to DNA saturation with small acid-soluble spore proteins (SASPs), suggests that reduced macromolecular motion is also critical in spore dry heat resistance. SASPs are also central in the radiation resistance characteristic of spores, where the contributions of four spore features-SASP; Ca2+, with pyridine-2,6-dicarboxylic acid (CaDPA); photoproduct lyase; and low water content-minimize DNA damage. Notably, the spore environment steers UV photochemistry toward a product that germinated spores can repair without significant mutagenesis. This resistance extends to chemicals and macromolecules that could damage spores. Macromolecules are excluded by the spore coat which impedes the passage of moieties of ≥10 kDa. Additionally, damaging chemicals may be degraded or neutralized by coat enzymes/proteins. However, the principal protective mechanism here is the inner membrane, a compressed structure lacking lipid fluidity and presenting a barrier to the diffusion of chemicals into the spore core; SASP saturation of DNA also protects against genotoxic chemicals. Spores are also resistant to other stresses, including high pressure and abrasion. Regardless, overarching mechanisms associated with resistance seem to revolve around reduced molecular motion, a fine balance between rigidity and flexibility, and perhaps efficient repair.