Comparison of the exploitation of methane-derived carbon by tubicolous and non-tubicolous chironomid larvae in a temperate eutrophic lake

Carbon and nitrogen stable isotope ratios (δ¹³C and δ¹⁵N) in three sympatric species of larval chironomids were analyzed in a temperate eutrophic shallow lake in Japan. Markedly lower δ¹³C values were reported in Chironomus plumosus (?51.2 ‰) and Tanypus sp. (?43.5 ‰) than those in photoautotrophic carbon sources [particulate organic matter (POM) and sediment]. There were positive correlations between δ¹³C and δ¹⁵N in the two chironomid species. These results indicated that they assimilated carbon derived from biogenic methane by exploiting methane-oxidizing bacteria (MOB). In contrast, Propsilocerus akamusi exhibited similar δ¹³C values to those of POM or sediment. A δ¹³C-based isotope mixing model was used to estimate the dietary contributions of MOB to each chironomid species. The mean contributions ranged from 11 to 15 % in C. plumosus, 13 to 19 % in Tanypus sp., but only up to 5 % in P. akamusi. In an aquarium, we observed that individuals of C. plumosus and Tanypus sp., which exhibited low δ¹³C values, built U-shaped larval tubes in the sediment, and an oxidized layer developed around these tubes. Propsilocerus akamusi did not exhibit this behavior. These results suggest that tube building may provide larval chironomids with greater access to methane-derived carbon through increased opportunities to feed on MOB.     

Responses of entomopathogenic fungi to the mutagen 4-nitroquinoline 1-oxide

Survival of entomopathogenic fungi under solar ultraviolet (UV) radiation is paramount to the success of biological control of insect pests and disease vectors. The mutagenic compound 4-nitroquinoline 1-oxide (4-NQO) is often used to mimic the biological effects of UV radiation on organisms. Therefore, we asked whether tolerance to 4-NQO could predict tolerance to UV radiation in thirty isolates of entomopathogenic fungi and one isolate of a xerophilic fungus. A dendrogram obtained from cluster analyses based on the 50 and 90 % inhibitory concentrations (IC₅₀ and IC₉₀, respectively) divided the fungal isolates into six clusters numbered consecutively based on their tolerance to 4-NQO. Cluster 6 contained species with highest tolerance to 4-NQO (IC₅₀ > 4.7 μM), including Mariannaea pruinosa, Lecanicillium aphanocladii, and Torrubiella homopterorum. Cluster 1 contained species least tolerant to 4-NQO (IC₅₀ < 0.2 μM), such as Metarhizium acridum (ARSEF 324), Tolypocladium geodes, and Metarhizium brunneum (ARSEF 7711). With few exceptions, the majority of Metarhizium species showed moderate to low tolerances (IC₅₀ between 0.4 and 0.9 μM) and were placed in cluster 2. Cluster 3 included species with moderate tolerance (IC₅₀ between 1.0 and 1.2 μM). In cluster 4 were species with moderate to high tolerance (IC₅₀ between 1.3 and 1.6 μM). Cluster 5 contained the species with high tolerance (IC₅₀ between 1.9 and 4.0 μM). The most UV tolerant isolate of M. acridum, ARSEF 324, was the least tolerant to 4-NQO. Also, L. aphanocladii, which is very susceptible to UV radiation, showed high tolerance to 4-NQO. Our results indicate that tolerance to 4-NQO does not correlate with tolerance to UV radiation. Therefore this chemical compound is not a predictor of UV tolerance in entomopathogenic fungi.     

A comparative analysis of photosynthetic recovery from thermal stress: a desert plant case study

Our understanding of the effects of heat stress on plant photosynthesis has progressed rapidly in recent years through the use of chlorophyll a fluorescence techniques. These methods frequently involve the treatment of leaves for several hours in dark conditions to estimate declines in maximum quantum yield of photsystem II (F _V/F _M), rarely accounting for the recovery of effective quantum yield (ΔF/F _M′) after thermally induced damage occurs. Exposure to high temperature extremes, however, can occur over minutes, rather than hours, and recent studies suggest that light influences damage recovery. Also, the current focus on agriculturally important crops may lead to assumptions about average stress responses and a poor understanding about the variation among species’ thermal tolerance. We present a chlorophyll a fluorescence protocol incorporating subsaturating light to address whether species’ thermal tolerance thresholds (T ₅₀) are related to the ability to recover from short-term heat stress in 41 Australian desert species. We found that damage incurred by 15-min thermal stress events was most strongly negatively correlated with the capacity of species to recover after a stress event of 50 °C in summer. Phylogenetically independent contrast analyses revealed that basal divergences partially explain this relationship. Although T ₅₀ and recovery capacity were positively correlated, the relationship was weaker for species with high T ₅₀ values (>51 °C). Results highlight that, even within a single desert biome, species vary widely in their physiological response to high temperature stress and recovery metrics provide more comprehensive information than damage metrics alone.     

Divergence of water balance mechanisms in two sibling species (Drosophila simulans and D. melanogaster): effects of growth temperatures

Drosophila simulans is more abundant under colder and drier montane habitats in the western Himalayas as compared to its sibling D. melanogaster but the mechanistic bases of such climatic adaptations are largely unknown. Previous studies have described D. simulans as a desiccation sensitive species which is inconsistent with its occurrence in temperate regions. We tested the hypothesis whether developmental plasticity of cuticular traits confers adaptive changes in water balance-related traits in the sibling species D. simulans and D. melanogaster. Our results are interesting in several respects. First, D. simulans grown at 15 °C possesses a high level of desiccation resistance in larvae (~39 h) and in adults (~86 h) whereas the corresponding values are quite low at 25 °C (larvae ~7 h; adults ~13 h). Interestingly, cuticular lipid mass was threefold higher in D. simulans grown at 15 °C as compared with 25 °C while there was no change in cuticular lipid mass in D. melanogaster. Second, developmental plasticity of body melanisation was evident in both species. Drosophila simulans showed higher melanisation at 15 °C as compared with D. melanogaster while the reverse trend was observed at 25 °C. Third, changes in water balance-related traits (bulk water, hemolymph and dehydration tolerance) showed superiority of D. simulans at 15 °C but of D. melanogaster at 25 °C growth temperature. Rate of carbohydrate utilization under desiccation stress did not differ at 15 °C in both the species. Fourth, effects of developmental plasticity on cuticular traits correspond with changes in the cuticular water loss i.e. water loss rates were higher at 25 °C as compared with 15 °C. Thus, D. simulans grown under cooler temperature was more desiccation tolerant than D. melanogaster. Finally, desiccation acclimation capacity of larvae and adults is higher for D. simulans reared at 15 °C but quite low at 25 °C. Thus, D. simulans and D. melanogaster have evolved different strategies of water conservation consistent with their adaptations to dry and wet habitats in the western Himalayas. Our results suggest that D. simulans from lowland localities seems vulnerable due to limited acclimation potential in the context of global climatic change in the western Himalayas. Finally, this is the first report on higher desiccation resistance of D. simulans due to developmental plasticity of both the cuticular traits (body melanisation and epicuticular lipid mass) when grown at 15 °C, which is consistent with its abundance in temperate regions.     

Isolation of extremely halophilic <Emphasis Type="Italic">Archaea</Emphasis> from a saline river in the Lut Desert of Iran,moderately resistant to desiccation and gamma radiation

Admittedly, the Lut Desert of Iran has been remained as an unexplored region from a microbiological standpoint. Domain Archaea contains extremophiles that can live in harsh habitats. Extremely halophilic archaea are exposed to different environmental stresses in the hypersaline environments such as high solar irradiance and periodic desiccation. Haloarchaeal diversity in Shoor River, a saline river in the Lut Desert (a salinity of 134.3 g L^–1 of dissolved salts), was investigated by a culture-dependent method. A large number of extremely halophilic isolates were obtained and a subset of 59 isolates was considered distinct. Firstly, the isolates were screened for their resistance under desiccation stress in 35 days. Eleven of these strains remained viable during the period in a desiccator containing silica gel. Then, three of them were randomly selected and their resistance against desiccation and ionizing radiation were determined. The isolates MS2, MS17, and MS50 were still recovered after 8 weeks in a desiccator and were moderately resistant to gamma radiation with D₁₀ value between 2 and 3 kGy. Strains MS2, MS17, and MS50 were affiliated with three species in the family Halobacteriaceae using 16S rRNA gene sequence analysis as well as morphological and biochemical characteristics—Haloterrigena jeotgali A29^T (99.6% similarity), Natrialba aegyptia 40^T (99.4% similarity) and Natrinema pallidum NCIMB 777^T (99.3% similarity), respectively. Although resistance to desiccation did not follow the sigmoid survival curve pattern of Deinococcus radiodurans, apparently haloarchaea can show a more resistance to desiccation in more long-term periods of time. This is the first report on isolation of extremely halophilic archaea belonged to the family Halobacteriaceae and their radioresistance and desiccation tolerance properties isolated from the Shoor River.     

Desiccation tolerance in diapausing spider mites Tetranychus urticae and T. kanzawai (Acari: Tetranychidae)

We investigated the effects of changes in vapor pressure deficit (VPD) on the survival of diapausing (winter form) and non-diapausing (summer form) spider mites Tetranychus urticae Koch and Tetranychus kanzawai Kishida (Acari: Tetranychidae). Adult females of both species were kept without food at VPDs of 0.0, 0.4, 0.7, 1.5, 1.9, or 2.7 kPa for 3, 6, 9, 12, or 15 days at 25 °C. Diapausing females of both species kept at a VPD of ≥0.4 kPa for ≥6 days clearly tolerated desiccation. Under water-saturated conditions (VPD = 0.0 kPa), in which no desiccation occurred, diapausing females showed high starvation tolerance: 90 % survived for up to 15 days. No interspecific differences in tolerance to desiccation or starvation were observed under most conditions. These results indicate that diapause functions increase tolerance to desiccation and starvation. Such multiple tolerances to harsh environments might support winter survival in spider mites.     

Emergence of Chironomidae from the shallow eutrophic Lake Kasumigaura,Japan

Seasonal chironomid emergence was monitored in the shallow eutrophic Lake Kasumigaura and 18 species were collected with a battery-operated light trap fixed on a floating stage and with surface emergence traps. During October–December, samples in the light trap comprised exclusively Tokunagayusurika akamusi (Tokunaga) and small numbers of one or two other species. T. akamusi, Procladuis (Holotanypus) culiciformis (L.), and Chironomus plumosus (L.) constituted 91.6% of the annual catch of chironomid adults. The predominance of T. akamusi (75.3 % of chironomid catch) and the high ratio (13) of T. akamusi to C. plumosus was more marked in this lake than other Japanese eutrophic lakes. Glyptotendipes tokunagai Sasa and Dicrotendipes pelochloris (Kieffer) were also caught abundantly with the light trap, but not with surface traps, indicating these were littoral species. The dry weight of emerging adults during May–December 1982 was 2.87 g m^–2, of which 1.92 gm^–2 (67%) was T. akamusi and 0.67 gm^–2 (23%) C. plumosus and 0.23 g m^–2 (8%) Clinotanypus sugiyamai Tokunaga and 0.03 gm^–2 (1%) P. (H.) culiciformis. The weight of emerging Tanypodinae was much higher than the annual mean larval biomass or estimated larval production, which have been due to underestimating the population density using an Ekman-Birge dredge. High numbers of individuals and species of chironomids were caught during April–July, presumably as a result of the high food supply for chironomid communities.     

Functional Genetic Diversity Analysis and Identification of Associated Simple Sequence Repeats and Amplified Fragment Length Polymorphism Markers to Drought Tolerance in Lentil (<Emphasis Type="Italic">Lens culinaris</Emphasis> ssp. <Emphasis Type="Italic">culinaris</Emphasis> Medicus) Landraces

Genetic diversity of 70 Mediterranean lentil (Lens culinaris ssp. culinaris Medicus) landraces was assessed using simple sequence repeats (SSRs) and amplified fragment length polymorphisms (AFLPs). These landraces were also assessed for variation in root and shoot traits and drought tolerance as estimated by relative water content (RWC), water losing rate (WLR) and wilting score (WS). Genetic diversity and clear differentiation of Moroccan landraces from those from northern Mediterranean regions (Italy, Turkey and Greece) were found. High genetic variation in root and shoot traits and traits related to drought tolerance was also observed. No relationship was found between drought tolerance of landraces and their geographic origin. Landraces with higher dry root biomass, chlorophyll content and root–shoot ratio were drought tolerant as evidenced by higher RWC and lower WLR and wilting severity. Kruskal–Wallis non-parametric test (K-W) was used to find SSRs and AFLPs associated with RWC, WLR and WS. Regression analysis showed six SSR and AFLP alleles explaining the highest phenotypic variation of RWC, WLR and WS (ranging from 21 to 50 % for SSRs and from 14 to 33 % for AFLPs). Functional genetic diversity analysis showed relationships between drought response of landraces and linked SSR and AFLP alleles to RWC, WLR and WS according to K-W test using canonical discriminant analysis. Our results confirm the feasibility of using association mapping to find DNA markers associated with drought tolerance in larger numbers of lentil landraces.     

Functional characteristics of a fruticose type of lichen, Stereocaulon foliolosum Nyl. in response to light and water stress

Stereocaulon foliolosum a fruticose type of lichen under its natural habitat is subjected to low temperature, high light conditions and frequent moisture stress due its rocky substratum. To understand as to how this lichen copes up with these stresses, we studied the reflectance properties, light utilization capacity and the desiccation tolerance under laboratory conditions. S. foliolosum showed light saturation point for photosynthesis at 390 μmol CO₂ m^?2 s^?1 and the light compensation point for photosynthesis at 64 μmol CO₂ m^?2 s^?1. Our experiments show that S. foliolosum has a low absorptivity (30–35 %) towards the incident light. The maximum rates of net photosynthesis and apparent electron transport observed were 1.9 μmol CO₂ m^?2 s^?1 and 45 μmol e^? m^?2 s^?1, respectively. The lichen recovers immediately after photoinhibition under low light conditions. S. foliolosum on subjecting to desiccation results in the decrease of light absorptivity and the reflectance properties associated with water status of the thalli show a change. During desiccation, a simultaneous decrease in photosynthesis, dark respiration and quenching in the fluorescence properties was observed. However, all the observed changes show a rapid recovery on rewetting the lichen. Our study shows that desiccation does not have a severe or long-term impact on S. foliolosum and the lichen is also well adapted to confront high light intensities.     

Roseovarius marisflavi sp. nov., isolated from an amphioxus breeding zone in the coastal region of the Yellow Sea, China

A novel Gram stain-negative, catalase- and oxidase-positive, strictly aerobic bacterium, designated strain H50^T, was isolated from an amphioxus breeding zone in the coastal region of the Yellow Sea, China. Cells were observed to be ovoid or short rods, lacked flagella and were found to contain bacteriochlorophyll a. Poly-beta-hydroxybutyrate was found to be accumulated. The temperature range for growth was determined to be 0–37 °C (optimum 28–37 °C). The halotolerance range for growth is 1–15 % NaCl (optimum 2–7 %). The pH range for growth is 6.0–8.0 (optimum 7.0). The major fatty acids were identified as C_18:1ω7c and C_16:0. The following polar lipids were found to be present: diphosphatidylglycerol, phosphatidylglycerol and a lipid. The predominant respiratory quinone was determined to be Q-10. DNA G+C content was determined to be 57.7 mol%. Strain H50^T exhibited the highest 16S rRNA gene sequence similarity to Pelagicola litoralis DSM 18290^T (96.1 %), Roseovarius mucosus DSM 17069^T (95.8 %) and Roseovarius tolerans DSM 11457^T (95.7 %). In the phylogenetic trees, strain H50^T was clustered with the genus Roseovarius but not Pelagicola. On the basis of phenotypic, chemotaxonomic and genotypic data, strain H50^T is considered to represent a novel species in the genus Roseovarius, for which the name Roseovarius marisflavi sp. nov. is proposed. The type strain is H50^T (=CGMCC 1.10799^T=JCM 17553^T).     

A Sunflower Lectin with Antifungal Properties and Putative Medical Mycology Applications

Using a new culture method for unculturable soil bacteria, we discovered a novel species, NHI-38^T, from the forest soil of Kyonggi University campus, South Korea. It was a Gram-positive, rod-shaped, and endospore-forming bacterial strain. It grew over a wide pH range (6.5–9.5), with an optimum range of pH 7–9, and in a wide range of temperatures (15–60 °C), with an optimum range of 35–45 °C. Growth was possible at 0–2 % NaCl concentration, and the optimal range was between 0.5 and 1.5 % NaCl. Phylogenetic analysis based on 16S rRNA gene sequences showed that this new species clustered within the genus Bacillus; it was closely related to “Bacillus abyssalis” SCSIO 15042^T (98.86 %), B. methanolicus NCIMB 13113^T (95.97 %), B. vietnamensis 15-1^T (95.8 %), B. seohaeanensis BH724^T (95.5 %), B. timonensis MM10403188^T (95.33 %), and B. subtilis subsp. subtilis NCIB 3610^T (94.87 %). The main fatty acid components of this bacterium were iso-C_15:0 (35.92 %), summed feature 3 (C_16:1ω7c/C_16:1ω6c; 16.92 %), and anteiso-C_15:0 (14.19 %). The predominant quinone in this bacterial strain was MK-7. The polar lipid profile primarily comprised phosphatidylethanolamine, phosphatidylglycerol, and diphosphatidylglycerol. The genomic DNA G+C composition of the isolate was 40.7 mol%. The DNA–DNA hybridization results indicated that this strain was distinct from other Bacillus species, the degree of similarity being 50 % with “B. abyssalis”, 56 % with B. methanolicus, 47 % with B. vietnamensis, 43 % with B. seohaeanensis, 46 % with B. timonensis, and 32 % with B. subtilis. Based on our results, we regard strain NHI-38^T as a novel member of the Bacillus genus, and we propose the name Bacillus thaonhiensis (=KACC 17216^T = KEMB 9005-019^T = JCM 18863^T).     

Interactions between soluble sugars and POPC (1-palmitoyl-2-oleoylphosphatidylcholine) during dehydration: vitrification of sugars alters the phase behavior of the phospholipid

The phase behavior of 1-palmitoyl-2-oleoylphosphatidylcholine (POPC) was characterized as a function of hydration in the presence of combinations of sugars representative of sugars found in seed embryos having differing degrees of desiccation tolerance. The tendency of the sugar mixes to vitrify was also monitored as a function of hydration. Using differential scanning calorimetry, it was found that all sugars diminished the increase in the gel-to-fluid phase transition temperature (T_m) of POPC that occurred upon dehydration of the pure lipid. These results are analyzed in terms of the osmotic and volumetric properties of sugars. Also, it was found that in those samples for which the glass transition temperature (T_g) was greater than the (T_m) of POPC, T_m was lowered by approx. 20 C° from the value for the fully hydrated lipid. X-ray diffraction data confirmed that acyl chain freezing was deferred to a lower temperature during cooling of vitrified samples. The significance of these results is discussed in terms of the ability of many organisms to tolerate desiccation.     

Exiguobacterium himgiriensis sp. nov. a novel member of the genus Exiguobacterium, isolated from the Indian Himalayas

The taxonomic position of an orange coloured bacterium, strain K22–26^T isolated from a soil sample was studied using a polyphasic approach. The organism had phenotypic and chemotaxonomic properties consistent with its allocation into the genus Exiguobacterium. Phylogenetic analysis of the 16S rRNA gene sequence showed that strain K22–26^T belongs to the genus Exiguobacterium and was related to Exiguobacterium aurantiacum DSM 6208^T (99.0 %) Exiguobacterium mexicanum DSM 16483^T (98.6 %), Exiguobacterium aquaticum (98.6 %), Exiguobacterium aestuarii DSM 16306^T (98.1 %), Exiguobacterium profundum DSM 17289^T (98.1 %) and Exiguobacterium marinum DSM 16483^T (97.9 %), whereas sequence similarity values with respect to other Exiguobacterium species with validly published names were between 92.5–94.0 %. The major polar lipids detected were phosphatidylglycerol, diphosphatidylglycerol and phosphatidylethanolamine. The major menaquinone was determined to be MK-7 (83 %) whereas MK-8 (11 %) and MK-6 (6 %) occur in smaller amounts. The peptidoglycan of the strain was found to contain l-lysine as the diagnostic diamino acid. The major fatty acids detected were iso C_13:0 (11.2 %), anteiso C_13:0 (15.4 %), iso C_15:0 (13.2 %) and iso C_17:0 (16.1 %). However, analysis of the DNA–DNA relatedness confirmed that strain K22–26^T belongs to a novel species. The G + C content of the strain K22–26^T was determined to be 50.1 mol %. The novel strain was distinguished from closely related type species of the genus Exiguobacterium using DNA–DNA relatedness and phenotypic data. Based on these differences, the strain K22–26^T should be classified as a novel species of the genus Exiguobacterium, for which the name Exiguobacterium himgiriensis sp. nov. strain K22–26^T (= MTCC 7628^T = JCM 14260^T) is proposed.     

Niabella thaonhiensis sp. nov., Isolated From the Forest Soil of Kyonggi University in Korea

Strain NHI-24^T was isolated from forest soil by a polycarbonate membrane transwell plate. It is a Gram-negative, rod-shaped, non-motile, non-spore-forming bacterium. Phylogenetic analysis based on 16S rRNA gene sequence data indicated that strain NHI-24^T is closely related to members of the genus Niabella: N. drilacis E90^T (97.7 %), N. tibetensis 15-4^T (96.7 %), N. aurantiaca R2A15-11^T (96.5 %), N. hirudinis E96^T (95.8 %), N. soli JS13-8^T (94.7 %), N. ginsengisoli NBRC106414^T (94.4 %), and N. yanshanensis CCBAU 05354^T (94.2 %). Growth temperatures range widely, from 15 to 37 °C, with 30 °C as the optimum. Salt tolerance ranges from 0 to 2 %. The strain grows at pH 6.5–11.0, with an optimal range of pH 7.0–9.5. Cells produce flexirubin-type pigments, and the predominant menaquinone is MK-7. The major fatty acids of strain NHI-24^T are iso-C_15:0 (36.72 %), iso-C_15:1 G (20.8 %), and summed feature 3 (C_16:1 ω7c/C_16:1 ω6c; 15.2 %). DNA–DNA hybridization values between strain NHI-24^T and members of the genus Niabella range from 37 to 53 %. Based on these results, it is proposed that strain NHI-24^T represents a novel species of the genus Niabella with the name Niabella thaonhiensis (= KACC 17215^T = KEMB 9005-018^T = JCM 18864^T).     

Haloplanus litoreus sp. nov. and Haloplanus ruber sp. nov., from a marine solar saltern and an aquaculture farm,respectively

Two halophilic archaea, strains GX21^T and R35^T, were isolated from a marine solar saltern and an aquaculture farm in China, respectively. Cells of the two strains were observed to be pleomorphic, flat, to contain gas vesicles, stain Gram-negative and produce red-pigmented colonies. Strain GX21^T was found to be able to grow at 25–50 °C (optimum 37 °C), at 2.6–4.8 M NaCl (optimum 3.4 M NaCl), at 0.05–1.0 M MgCl₂ (optimum 0.1 M MgCl₂) and at pH 6.0–8.5 (optimum pH 6.5) while strain R35^T was found to be able to grow at 25–45 °C (optimum 37 °C), at 2.1–4.8 M NaCl (optimum 3.1 M NaCl), at 0–0.7 M MgCl₂ (optimum 0.03 M MgCl₂) and at pH 5.5–9.5 (optimum pH 6.5–7.0). The cells of both isolates were observed to lyse in distilled water. The minimum NaCl concentrations that prevented cell lysis were determined to be 15 % (w/v) for strain GX21^T and 12 % (w/v) for strain R35^T. The major polar lipids of the two strains were identified as phosphatidylglycerol, phosphatidylglycerol phosphate methyl ester, phosphatidylglycerol sulfate, one major glycolipid and a minor lipid chromatographically identical to sulfated mannosyl glucosyl diether and mannosyl glucosyl diether, respectively. 16S rRNA gene sequence analysis revealed that strains GX21^T and R35^T show 97.1 % sequence similarity to each other and are closely related to Haloplanus aerogenes TBN37^T (96.8 and 95.8 %), Haloplanus vescus RO5-8^T (96.7 and 96.1 %), Haloplanus salinus YGH66^T (96.4 and 95.8 %) and Haloplanus natans JCM 14081^T (96.3 and 95.4 %). The rpoB′ gene similarity between strains GX21^T and R35^T is 90.5 % and show 88.5–90.8 % similarity to the Haloplanus species with validly published names. The DNA G+C content of strain GX21^T and R35^T were determined to be 65.8 and 66.0 mol%, respectively. The DNA–DNA hybridization values between strain GX21^T and strain R35^T, and the two strains with the Haloplanus species with validly published names, showed less than 50 % DNA–DNA relatedness. It was concluded that strain GX21^T (=CGMCC 1.10456^T = JCM 17092^T) and strain R35^T (=CGMCC 1.10594 ^T = JCM 17271^T) represent two new species of Haloplanus, for which the names Haloplanus litoreus sp. nov. and Haloplanus ruber sp. nov. are proposed.     

Influence of temperature on the in vitro pollen germination and pollen tube growth of various native Iranian almonds (Prunus L. spp.) species

Pollen germination and pollen tube growth was quantified among various native Iranian wild almonds (P. dulcis (Mill.) D. A. Webb, P. eleaegnifolia Mill., P. orientalis Mill., P. lycioides Spach, P. reuteri Bioss. et Bushe, P. arabica Olivier, P. glauca Browick and P. scoparia Spach in order to identify differences in the tolerance of pollen to temperature variations. Pollen germination and pollen tube growth were observed after incubation in darkness in a germination medium for 24?h at 10?C50°C at 5°C intervals. Maximum pollen germination of the wild almond species and specify that 60% was obtained for P. orientalis pollen and 98% for P. scoparia. Pollen tube length ranged from 860???m was obtained in P. lycioides and 1490???m in P. scoparia. A modified bilinear model best described the response to temperature of pollen germination and pollen tube length. Almond species variation was found for cardinal temperatures (T _min, T _opt and T _max) of pollen germination percentage and pollen tube growth. Mean cardinal temperatures averaged over eight almond species were 14.7, 24.2, and 43.7°C for maximum percentage pollen germination and 14.48, 25.3, and 44.4 °C for maximum pollen tube length. The principal component analysis (PCA) identified maximum percentage pollen germination and pollen tube length of the species, and T _max for the two processes as the most important pollen parameters in describing a species tolerance to high temperature. PCA also classified Prunus L. spp. into four groups according to the tolerance of pollen to temperature variations. The T _min and T _opt for pollen germination and tube growth, rate of pollen tube growth were less predictive in discriminating species for high temperature tolerance.     

Critical moisture content for successful cryopreservation of embryonic axes of <Emphasis Type="Italic">Fortunella polyandra</Emphasis> determined by differential scanning calorimetry (DSC)

The relationships between water content of desiccated embryonic axes (using different methods of desiccation), the availability of water determined by differential scanning calorimetry (DSC) analysis and recovery percentage after liquid nitrogen (LN) exposure of Fortunella polyandra embryonic axes were investigated. The objectives were to understand thermal properties of desiccated embryonic axes during cryopreservation and to determine the critical moisture contents for successful cryopreservation of the embryonic axes. Excised embryonic axes were desiccated under laminar air flow (0, 10, 15, 30 and 45 min), over silica gel (0, 5, 15, 30 and 60 min), and ultra-rapidly (0, 5, 10, 20 and 25 min). Desiccation under laminar air flow resulted in an optimal water content of 0.150 gH₂O g^?1 dw and a survival of 50 % after cryopreservation, while the unfrozen water content (WC_u) was 0.126 gH₂O g^?1 dw. After drying over silica gel, the optimal water content was 0.190 gH₂O g^?1 dw, where the survival was 40 % after cryopreservation and the WC_u was determined as 0.177 gH₂O g^?1 dw. Using the flash-drying method, the optimal water content was found to be 0.145 gH₂O g^?1 dw, the survival was 50 % after cryopreservation and the WC_u was 0.133 gH₂O g^?1 dw. Embryonic axes of F. polyandra showed low-to-moderate tolerance to desiccation. The results of the freezing transitions for all the desiccation times and methods showed that the onset temperature and the peak of the mean enthalpy decreased in size with decreasing water content. DSC elucidated the critical moisture contents and the cooling and melt enthalpies for successful cryopreservation of F. polyandra embryonic axes.     

Parvularcula oceanus sp. nov., isolated from deep-sea water of the Southeastern Pacific Ocean

A Gram-negative, aerobic, motile by single polar flagellum, short rod-shaped bacterium was isolated from a deep-seawater sample of the Southeastern Pacific Ocean. Growth was found to occur at 10–40 °C, at pH 4.0–10.0 and in the presence of 0–9.0 % (w/v) NaCl. The phylogenetic tree based on 16S rRNA gene sequences showed that strain JLT2013^T fell within a clade comprising species of the genus Parvularcula and formed a coherent cluster with Parvularcula lutaonensis CC-MMS-1^T (neighbour-joining phylogenetic tree) or Parvularcula dongshanensis SH25^T (maximum-likelihood and maximum-parsimony phylogenetic trees). Sequence similarity analyses based on 16S rRNA gene sequences revealed that strain JLT2013^T shows high sequence similarity to P. lutaonensis CC-MMS-1^T (96.7 %), P. dongshanensis SH25^T (96.0 %) and Parvularcula bermudensis HTCC2503^T (95.2 %). The major cellular fatty acids were identified as C_12:0 (34.3 %), summed feature 8 (C_18:1 ω7c and/or C_18:1 ω6c) (10.9 %), C_16:0 (10.0 %) and C_17:1 ω6c (7.2 %). The polar lipids were found to include diphosphatidylglycerol, phosphatidylglycerol, three sphingoglycolipids and three unknown glycolipids. Strain JLT2013^T was found to contain Q-10 as the predominant quinone. The DNA G+C content was determined to be 66.3 mol%. In the light of the phenotypic characteristics, chemotaxonomic features and phylogenetic evidence gathered in this study, strain JLT2013^T (=LMG 27362^T = CGMCC 1.12400^T) should be classified as a novel species in the genus Parvularcula, for which the name Parvularcula oceanus sp. nov. is proposed.     

The Xenon Test Chamber Q-SUN® for testing realistic tolerances of fungi exposed to simulated full spectrum solar radiation

The low survival of insect-pathogenic fungi when used for insect control in agriculture is mainly due to the deleterious effects of ultraviolet radiation and heat from solar irradiation. In this study, conidia of 15 species of entomopathogenic fungi were exposed to simulated full-spectrum solar radiation emitted by a Xenon Test Chamber Q-SUN XE-3-HC 340S (Q-LAB^® Corporation, Westlake, OH, USA), which very closely simulates full-spectrum solar radiation. A dendrogram obtained from cluster analyses, based on lethal time 50 % and 90 % calculated by Probit analyses, separated the fungi into three clusters: cluster 3 contains species with highest tolerance to simulated full-spectrum solar radiation, included Metarhizium acridum, Cladosporium herbarum, and Trichothecium roseum with LT₅₀ > 200 min irradiation. Cluster 2 contains eight species with moderate UV tolerance: Aschersonia aleyrodis, Isaria fumosorosea, Mariannaea pruinosa, Metarhizium anisopliae, Metarhizium brunneum, Metarhizium robertsii, Simplicillium lanosoniveum, and Torrubiella homopterorum with LT₅₀ between 120 and 150 min irradiation. The four species in cluster 1 had the lowest UV tolerance: Lecanicillium aphanocladii, Beauveria bassiana, Tolypocladium cylindrosporum, and Tolypocladium inflatum with LT₅₀ < 120 min irradiation. The QSUN Xenon Test Chamber XE3 is often used by the pharmaceutical and automotive industry to test light stability and weathering, respectively, but it was never used to evaluate fungal tolerance to full-spectrum solar radiation before. We conclude that the equipment provided an excellent tool for testing realistic tolerances of fungi to full-spectrum solar radiation of microbial agents for insect biological control in agriculture.     

A comparison of partial dehydration and hydrated storage-induced changes in viability,reactive oxygen species production,and glutathione metabolism in two contrasting recalcitrant-seeded species

This study compared the responses of Avicennia marina and Trichilia dregeana seeds, both of which are recalcitrant, to partial dehydration and storage. Seeds of A. marina exhibited a faster rate of water and viability loss (± 50% viability loss in 4 days) during partial dehydration, compared with T. dregeana (± 50% viability loss in 14 days). In A. marina embryonic axes, reactive oxygen species (ROS) production peaked on 4 days of dehydration and was accompanied by an increase in the GSH:GSSG ratio; it appears that the glutathione system alone could not overcome dehydration-induced oxidative stress in this species. In A. marina, ROS and axis water content levels increased during hydrated storage and were accompanied by a decline in the GSH:GSSG ratio and rapid viability loss. In T. dregeana embryonic axes, ROS production (particularly hydrogen peroxide) initially increased and thereafter decreased during both partial dehydration and hydrated storage. Unlike in A. marina embryonic axes, this reduced ROS production was accompanied by a decline in the GSH:GSSG ratio. While T. dregeana seeds may have incurred some oxidative stress during storage, a delay in and/or suppression of the ROS-based trigger for germination may account for their significantly longer storage longevity compared with A. marina. Mechanisms of desiccation-induced seed viability loss may differ across recalcitrant-seeded species based on the rate and extent to which they lose water during partial drying and storage. While recalcitrant seed desiccation sensitivity and, by implication, storage longevity are modulated by redox metabolism, the specific ROS and antioxidants that contribute to this control may differ across species.