Planetary Protection (PP) is the practice of safeguarding solar system bodies from terrestrial biological contamination and screening the Earth against potentially harmful extraterrestrial biological contamination. On Earth, cleanrooms and spacecraft surfaces are assayed using swabs and wipes that are then heat shocked for 15 min at 80°C to select for spores. The samples are further processed using the pour-plate method and Petri plates (TSA plates), with trypticase soy agar (TSA) serving as the growth medium. This sampling and processing procedure, called the NASA Standard Assay (NSA), is used by PP engineers around the world. Recent years have seen an increase in the incorporation of state-of-the-art technology, such as membrane filtration, into the NSA, with a push for implementing environmentally friendly technology into day-to-day activities. Dehydrated thin film media, such as Petrifilm Rapid Aerobic Count (RAC) plates, suit these goals as an alternative method to TSA plates. RAC plates show bacterial growth (and distinguish colonies from foreign particles such as bubbles) faster than TSA plates due to the incorporation of chromogenic colour indicators in the media. RAC plates also possess a much smaller environmental footprint than TSA plates, and are designed to evaluate even some of the challenging-to-detect environmental organisms, including spreaders that fill over 25% of the plate area in only a few hours. With these benefits in mind the PP Group at the NASA Jet Propulsion Laboratory took on the task of comparing RAC plates directly to TSA plates within the context of the NSA. Not only were the RAC plates able to detect surface environmental samples and in vitro spiked samples equivalent to NSA-processed TSA plates, but spreader organisms were countable on RAC plates at culture densities 10- to 100-fold greater than on TSA plates. In addition, RAC plates showed a robust, linear detection capability when challenged with membrane filter incorporation and organisms were easily acquired from RAC plates for archiving or post-processing experiments including MALDI-TOF bacterial identification. With their ease of use, small footprint, and both rapid and accurate bioburden measurements, RAC plates have the potential to overcome limitations posed by current PP culturing protocols.

Desiccation-tolerant (DT) plant germplasm (i.e. seeds, pollen and spores) survive drying to low moisture contents, when cytoplasm solidifies, forming a glass, and chemical reactions are slowed. DT germplasm may survive for long periods in this state, though inter-specific and intra-specific variation occurs and is not currently explained. Such variability has consequences for agriculture, forestry and biodiversity conservation. Longevity was previously considered in the context of morphological features, cellular constituents or habitat characteristics. We suggest, however, that a biophysical perspective, which considers the molecular organization – or structure – within dried cytoplasm, can provide a more integrated understanding of the fundamental mechanisms that control ageing rates, hence the variation of longevity among species and cell types. Based on biochemical composition and physical–chemical properties of dried materials, we explore three types of the interplay between structural conformations of dried cytoplasm and ageing: (1) cells that lack chlorophyll and contain few storage lipids may exhibit long shelf life, with ageing probably occurring through slow autoxidative processes within the glassy matrix as it relaxes; (2) cells with active chlorophyll may die quickly, possibly because they are prone to oxidative stress promoted by the photosynthetic pigments in the absence of metabolic water and (3) cells that lack chloroplasts but contain high storage lipids may die quickly during storage at −20°C, possibly because lipids crystallize and destabilize the glassy matrix. Understanding the complex variation in structural conformation in space and time may help to design strategies that increase longevity in germplasm with generally poor shelf life.

Pollen, spores, phytoliths, and microscopic charcoal from a sedimentary column in Hall's Cave, south-central Texas, provide information for local and regional vegetation change during the last deglaciation and the Holocene in the context of broader regional and global climatic changes. The combination of paleoenvironmental proxy data from the cave indicates that between about 18,000 and 16,500 cal yr BP the cave area was dominated by an open plant community consisting of herbaceous vegetation, dominated by C3 grasses, and scattered trees, primarily Quercus and Pinus species. After about 16,500 cal yr BP, the arboreal component fluctuated, attaining a peak between 14,000 and 13,000 cal yr BP with relatively equal proportions of C3 and C4 grasses, including a sizable proportion of Panicoideae grasses. The Younger Dryas is marked by a conspicuous decrease in arboreal pollen with an apparent increase of C4 grasses toward its termination. Early Holocene recovery of arboreal vegetation is followed by a drying trend marked by the increasing dominance of C4 drought-tolerant Chloridoideae grasses. Increasing human use of the cave in middle to late Holocene times creates noise in the climatic significance of pollen, phytolith, and other proxies, a factor to consider when interpreting paleoenvironmental proxies in other cave sedimentary records.

Many researchers are investigating the extreme resilience of bacterial endospores against chemical and physical inactivating agents. The presence of vegetative cells in spore suspensions can result in overly optimistic assessment of inactivating agents; therefore, various spore purification methods have been applied to separate spores from vegetative cells prior to testing. The present study was undertaken to evaluate the effect of two widely used spore purification methodologies on spore integrity and susceptibility to ultraviolet-A (UVA) radiation and free radicals generated from photocatalysts. Bacillus subtilis and Bacillus cereus spores were purified by procedures that involved heat shock alone or chemical washes, lysozyme treatment and heat shock (CLH). The purified spores were exposed to UVA radiation or free radicals generated by photocatalyst and susceptibility were evaluated in terms of survival ratio. The effect of purification procedure on the spore morphology was investigated with electron microscopy. The CLH purification process significantly damages spore coats and increases the susceptibility of Bacillus spores to UVA radiation and photocatalytic inactivation. It is therefore likely that the survival of CLH treated spores in extra-terrestrial environments would be less than that of the same spores purified by a less aggressive procedure.

Clostridia in the milk can lead to late blowing, a cheese defect. Clostridia are ubiquitous, deriving from both the farm environment and the feed ingested by the cows, and are transferred into the milk through faecal contamination. Our aim was to investigate the effect of different in-parlour practices on the content of anaerobic spore-forming bacteria in milk, and to monitor the variation in spore content in the feed and environment. The experiment, conducted in an experimental dairy during autumn, was repeated in exactly the same way for two consecutive years. The experimental design applied three different milking routines in three consecutive 7-d periods: forestripping alone (F); forestripping and post-dipping (F+Post); pre-dipping, wiping, forestripping and post-dipping (Pre+F+Post). Teat skin swabs and samples of feed, faeces, bedding materials and milk were collected for microbiological analyses. The dietary forage of the lactating cows included maize silage, which, in both years, was found to have the highest level of clostridial spore contamination. Pre-dipping with a detergent/emollient solution, and drying with a disposable paper towel, proved much more efficient in reducing spore contamination than forestripping alone, both on the teats (1·30 vs. 2·20 log10 MPN/swab; P < 0·001) and in the milk (1·82 vs. 2·47 log10 MPN/L, P < 0·02), while post-dipping had little influence on spore count. The standard plate count in milk was significantly lower with Pre+F+Post treatment than with F (3·80 vs. 4·51 log10 CFU/mL, P < 0·01). The teat preparation procedure did not influence the lactic acid bacterial levels in the milk, which is very positive in that decreased lactic acid bacterial content can lessen raw milk cheese quality.

Old World climbing fern (OWCF) is a highly invasive fern that disrupts natural communities in central and southern Florida. OCWF produces copious, wind-blown spores that have propelled its rapid invasion of Florida's natural areas over the last few decades. Current management of OWCF is limited to herbicides and natural resource managers in Florida have questioned if herbicides inhibit spore germination. This study compared spore germination rates of OWCF exposed to six herbicides and a surfactant from 1 to 24 h under laboratory conditions. Spores of OWCF were highly susceptible to metsulfuron, but exhibited tolerance to imazapyr, glyphosate, fluroxypyr, asulam, and triclopyr. Spore germination rates were 0.4% for spores exposed to 0.1 g ai L−1 of metsulfuron, but 0% for rates greater than or equal to 0.2 g ai L−1 at 30 d after treatment (DAT). Reduction in spore germination was observed with all other concentrations of herbicides tested, ranging from 10.4% with triclopyr (40 g ai L−1) to 42.6% with asulam (4.2 g ai L−1) compared to 47.9% germination for untreated checks 30 DAT. Spores were highly sensitive to metsulfuron with herbicide concentrations required for 50 and 95% inhibition of spore germination (I50 and I95) measuring 0.014 and 0.063 g ai L−1, respectively; spores were greater than 1,000-fold more sensitive to metsulfuron compared to I95 concentrations of any other herbicide tested. These results indicate that metsulfuron exhibits potential to control OWCF spore germination but spores are tolerant to the five other herbicides tested.

Pollen, spore, macrofossil and stable isotope (C and N) analyses from a 266-cm sediment core collected from a swamp on the Eastern Arc Mountains, Tanzania, are used to reconstruct vegetation and environmental history. An estimated time scale based on five14C ages records approximately 38,000 yr. This palaeorecord is the first from this biodiversity hotspot and importantly extends through the last glacial maximum (LGM). The altitudinal transition from montane to upper montane forest shifted from 1700–1800 m (38,00014C yr BP) to 1800–1900 m (35,000–29,00014C yr BP). From 29,000 to 10,00014C yr BP, it shifted from 1850–1950 m across the LGM to 1750–1800 m (during 10,000–350014C yr BP), and to present-day elevations at 2000 m during the last 350014C yr BP. The relative ecosystem stability across the LGM may be explained by the Indian Ocean's influence in maintaining continuous moist forest cover during a period of East African regional climate aridity. During the late Holocene, presence of abundant coprophilous fungi and algal blooms demonstrates increasing human impact.Neurospora spores indicate frequent fires, coinciding with clear signals of decline inPodocarpus and Psychotria trees that possibly represent selective logging.

Although it has long been acknowledged that seed characteristics are of major importance to the conquest of tree crowns by vascular epiphytes, there is surprisingly little quantitative evidence on the aerodynamic properties of their diaspores. We used a custom-built device to determine the terminal velocity (Vterm) of falling seeds, a parameter that has been shown to have high predictive power for the wind dispersal potential of diaspores under natural conditions. We determined Vterm of 45 species of epiphytic and terrestrial Orchidaceae, which almost doubles the currently available database for this family. Although varying by a factor of five with values of 0.09–0.4 m s−1, Vterm was invariably very slow compared to plants in general. For each species, we also took morphological data and determined seed mass. None of these parameters was linearly correlated with Vterm and neither did the average Vterm differ between species found in the two habitats, although seeds of terrestrial taxa were significantly larger and heavier. Finally, we demonstrate the potential of our device to measure Vterm of even smaller diaspores by successfully quantifying Vterm of fern spores. This tool has much potential for the quantitative study of dispersal of plants with tiny diaspores, particularly in a conservation context in fragmented landscapes.

Bacterial endospores are resistant to many environmental factors from temperature extremes to ultraviolet irradiation and are generally more difficult to inactivate or kill than vegetative bacterial cells. It is often considered necessary to treat spores or samples containing spores with chemical fixative solutions for prolonged periods of time (e.g., 1–21 days) to achieve fixation/inactivation to enable electron microscopy (EM) examination outside of containment laboratories. Prolonged exposure to chemical fixatives, however, can alter the ultrastructure of spores for EM analyses. This study was undertaken to determine the minimum amount of time required to inactivate/sterilize and fix spore preparations from several bacterial species using a universal fixative solution for EM that maintains the ultrastructural integrity of the spores. We show that a solution of 4% paraformaldehyde with 1% glutaraldehyde inactivated spore preparations of Bacillus anthracis, Bacillus cereus, Bacillus megaterium, Bacillus thuringiensis, and Clostridium perfringens in 30 min, and Bacillus subtilis in 240 min. These results suggest that this fixative solution can be used to inactivate and fix spores from several major groups of bacterial spore formers after 240 min, enabling the fixed preparations to be removed from biocontainment and safely analyzed by EM outside of biocontainment.

The sunbleak (Leucaspius delineatus), a cyprinid fish native to continental Europe and now established in the UK, is experiencing population decline which appears to be linked to the spread of the invasive Asian cyprinid (Pseudorasbora parva). A population of sunbleak in the UK has previously been identified as infected with S. destruens at low prevalence. Because Sphaerothaecum destruens has, on occasion, caused severe disease in cultured and wild salmonids the aim of this work was to establish laboratory cultures of S. destruens from sunbleak in the UK and use these cultures in challenge experiments to determine if the UK isolate of S. destruens from cyprinid species is a potential threat to Atlantic salmon (Salmo salar). The first isolation and culture of S. destruens in the UK and from a cyprinid species is described. Cultured S. destruens spores from sunbleak are infective to EPC, CHSE and FHM cells, replicating most rapidly in FHM and EPC cells. Spores can be induced to zoosporulate in water forming motile, uni-flagellated zoospores. Challenge experiments indicated the spores are able to replicate and disperse in Atlantic salmon and are associated with increased mortality (up to 90%) when injected intraperitonealy.

Planetary protection regulations are in place to control the contamination of planets and moons with terrestrial micro-organisms in order to avoid jeopardizing future scientific investigations relating to the search for life. One environmental chemical factor of relevance in extraterrestrial environments, specifically in the moons of the outer solar system, is ammonia (NH3). Ammonia is known to be highly toxic to micro-organisms and may disrupt proton motive force, interfere with cellular redox reactions or cause an increase of cell pH. To test the survival potential of terrestrial micro-organisms exposed to such cold, ammonia-rich environments, and to judge whether current planetary protection regulations are sufficient, soil samples were exposed to concentrations of NH3 from 5 to 35% (v/v) at −80°C and room temperature for periods up to 11 months. Following exposure to 35% NH3, diverse spore-forming taxa survived, including representatives of the Firmicutes (Bacillus, Sporosarcina, Viridibacillus, Paenibacillus, Staphylococcus and Brevibacillus) and Actinobacteria (Streptomyces). Non-spore forming organisms also survived, including Proteobacteria (Pseudomonas) and Actinobacteria (Arthrobacter) that are known to have environmentally resistant resting states. Clostridium spp. were isolated from the exposed soil under anaerobic culture. High NH3 was shown to cause a reduction in viability of spores over time, but spore morphology was not visibly altered. In addition to its implications for planetary protection, these data show that a large number of bacteria, potentially including spore-forming pathogens, but also environmentally resistant non-spore-formers, can survive high ammonia concentrations.

The Châteaupanne Unit belongs to the South Armorican domain of the Armorican Massif (France), which is part of the Variscan belt. This unit includes two Lower Devonian plant levels and one of them corresponds to the Basal Member of the Chalonnes Formation. A sedimentological and palaeontological analysis of these fossiliferous deposits from the Châteaupanne quarry (Montjean/Loire, Maine et Loire, France) is presented here for the first time. The age determination based on palynology indicates that the locality records the earliest occurrence of plant megafossils in the Armorican Massif. Their presence suggests an emergence event that has never been described before. Our study highlights the promising potential of the Basal Member of the Chalonnes Formation to aid in understanding these occurrences, and provides new insights into the history of the Variscan belt.

Study of additional collections of Selaginella chiquitana M.Kessler, A.R.Sm. & M.Lehnert shows it to be conspecific with S. arroyoana M.Kessler & A.R.Sm. The apparent relationships of Selaginella arroyoana, its ecology and conservation status are discussed more fully. Scanning electron micrographs of spores and a map of its distribution are provided.

Since the late 1980s an extensive programme of trenching/borehole drilling has been undertaken in order to study the Lower Devonian ‘Lower Old Red Sandstone’ deposits of the Rhynie outlier in the Grampian Highlands of Scotland. The boreholes have provided new information on the stratigraphical succession and geological structure of the Rhynie outlier, both of which were hitherto poorly understood due to the paucity of good surface exposure and the complex geological relationships of the deposits. One hundred and eighteen palynological samples were collected, representing much of the stratigraphical sequence of the inlier, of which 106 were productive. Productive samples yield assemblages of well preserved palynomorphs, dominated by spores and phytodebris, but also containing arthropod cuticle and rare freshwater algal remains. The spore assemblages are systematically described and two new genera and six new species proposed. They are similar throughout the sequence and the spores belong to the polygonalis–emsiensis Spore Assemblage Biozone of Richardson & McGregor (1986) and the PoW Oppel Zone (possibly Su Interval Zone) of Streel et al. (1987), indicating an early (but not earliest) Pragian–?earliest Emsian age range, that may possibly be restricted to latest Pragian–?earliest Emsian. The palynomorph assemblages contain only terrestrial forms, supporting sedimentological interpretation of the deposits as ‘Lower Old Red Sandstone’ fluviatile and lacustrine deposits, with occasional extrusive volcanics and volcaniclastic sediments intercalated. The palynomorphs are of variable thermal maturity (within and between samples), probably reflecting differential heating associated with the complex volcanic/hydrothermal system. The new palynological data provide, for the first time, a reliable biostratigraphical age for the deposits, and suggest that they accumulated relatively rapidly. Spore biostratigraphy and thermal maturity studies facilitate correlation of the tectonically complex deposits, and shed light on other aspects of the geological history of the outlier. The palynomorph assemblages also aid interpretation of the biota of the Rhynie basin, including the exceptionally preserved biotas of the Rhynie and Windyfield cherts.

Spores of the biocontrol agent, Streptomyces melanosporofaciens EF-76, were entrapped by complex coacervation in beads composed of a macromolecular complex (MC) of chitosan and polyphosphate. A proportion of spores entrapped in beads survived the entrapment procedure as shown by treating spores from chitosan beads with a dye allowing the differentiation of live and dead cells. The spore-loaded chitosan beads could be digested by a chitosanase, suggesting that, once introduced in soil, the beads would be degraded to release the biocontrol agent. Spore-loaded beads were examined by optical and scanning electron microscopy because the release of the biological agent depends on the spore distribution in the chitosan beads. The microscopic examination revealed that the beads had a porous surface and contained a network of inner microfibrils. Spores were entrapped in both the chitosan microfibrils and the bead lacuna.

The palynological content of randomly collected sedimentary rock clasts from the till on the south-east slope of the Basen nunatak in northern Vestfjella in western Dronning Maud Land indicate that these sedimentary rocks were derived from strata of Middle Permian age. The palynological content and preservation is similar to palynofloras described from the sedimentary rocks that crop out at the Fossilryggen nunatak to the south-east, therefore, it seems likely that the Fossilryggen area represents the source of the sedimentary rock samples in the Basen till. This is further supported by known ice flow directions obtained from striations and clast fabric measurements in the area.

The red algae generally are considered to have no motile stages. We have confirmed sporadic reports of motile spores in a few red algae by recording freshly released live spores with time-lapse videomicroscopy. Of the 25+ species investigated, only a few had spores that appeared to be immobile. Cells of unicellular species often displayed active movement although were otherwise indistinguishable from nearby immobile cells, and these may be equivalent to the motile spores released after differentiation in more complex multicellular species. There was considerable variation among members of the Bangiophycidae. Cells of Porphyridium often moved at around 0·66 μm s-1 and had conspicuous mucilage tails. Flintiella and Rhodospora showed no cellular movement. Rhodosorus sometimes moved a little and all four strains displayed continuous cytoplasmic rotation within the wall. Glaucosphaera was inert but displayed formation and transport of vesicles from the perinuclear region to the surface where they were discharged. Spores (whether monospores, tetraspores or carpospores) of almost all other species or strains available displayed various forms of motility. Some (e.g. Batrachospermum-Chantransia monospores) showed smooth, directional and continuous gliding (c. 2·2 μm s-1) for shorter or longer distances, clearly detectable to the naked eye through the microscope. In others, movement could be almost as fast or slower, non-continuous and undirectional. Certain spores (e.g. monospores of the filamentous Audouinella sp.) were amoeboid, and in some cases (e.g. Sahlingia) cells actively squeezed through the irregular interstices of a crustose colony. The mechanism of movement is unknown; polysaccharide secretion may be involved in some cases. These forms of motility may be significant as dispersal mechanisms, by moving spores out of the stagnant boundary layer, and in settling processes, by allowing spores limited ability to optimize their site of germination.

Abuscular mycorrhizal fungi are thought to survive adverse environmental conditions primarily as spores. Extraradical mycelia of two Glomus species were produced in fine mesh pouches which excluded roots but not hyphae. The mycelia in these pouches were exposed to freezing conditions, either in the field or in a controlled-temperature chamber. Bioassay plants were grown directly in the pouches and mycorrhizal colonization was assessed after 1 month. The mycelia remained infective in frozen soil over winter. This survival was not dependent on either the presence of root pieces or on the connection of mycelia to roots. Spores were not an effective inoculum in these bioassays. Overwinter survival of mycelia would enable plants to become incorporated into functional mycorrhizal associations early in spring.

In the SW part of the Southern Uplands of Scotland the relatively thin Moffat Shale Group (late Ordovician–early Silurian) is succeeded by a thick development of Silurian greywackes, of variable turbiditic facies. This includes late Llandovery (Telychian) quartzose greywackes with interbedded thin graptolitic shales of the turriculatus and crispus biozones, in the upper part of the Gala Group, a sequencewhich is laterally equivalent to the basal part of the Hawick Group. The age of the finer-grained calcareous Hawick Group, which here includes 1. the Ross Formation, ranges from late Llandovery (turriculatus Biozone) to early Wenlock (riccartonensis Biozone). The Riccarton Group, which contains thick units of thinly-bedded siltstones and mudstones, is of Wenlock age (riccartonensis to lundgreni biozones). Within this sequence, all the biozones of the standard graptolite zonal scheme have been recognised in the area, with the exception of the crenulata Biozone of the late Llandovery (Telychian Stage) and the murchisoni and ellesae biozones of the Wenlock (Sheinwoodian Stage). Details of the graptolite biostratigraphy areclosely comparable with those of the markedly thinner sequences of northern England. Acritarchs occur throughout the sequence but are most numerous and best preserved in the Gala Group. Poorly preserved chitinozoa and spores are also present, the former occurring sporadically throughout the succession but the latter become common only in the Riccarton Group.