The Effect of Shearing in the Thermo-mechanical Properties of Candelilla Wax and Candelilla Wax�CTripalmitin Organogels

We investigated the shearing effect in the thermo-mechanical properties of candelilla wax (CW) and candelilla wax–tripalmitin (CW-TP) organogels developed using safflower oil as the liquid phase. A shear rate of 600 s⁻¹ was applied during cooling (1 °C/min) of 3% CW and 3% CW-1% TP solutions, until reaching nucleation (i.e., 47 °C) or metastable conditions (i.e., 52 °C) then allowing the development of the organogel under quiescent conditions at 15 °C. The thermal and rheological properties of these organogels were compared with the ones of organogels developed under static conditions. The X-ray results showed that under static conditions the CW crystallized in an orthorhombic ( O _^ ) \left( {{{\hbox{O}}_{ \bot }}} \right) subcell packing with a lateral stacking with a length (L) equivalent to the hydrocarbon chain’s length. During organogelation of the 3% CW-1% TP solution, CW and TP co-crystallized in a O _^ {{\hbox{O}}_{ \bot }} subcell packing with TP in a 2L stacking organization. The application of shearing did not modify the molecular packing of the crystals or the melting properties of the organogels. However, the CW and CW-TP organogels developed with shearing showed the formation of larger crystals (i.e., fiber-like or plate-like) in comparison with the ones developed under static conditions. The presence of 1% TP increased the solid fat content, and thus the CW-TP organogels showed higher elasticity (G′) than CW organogels. The organogels developed with the application of shearing until reaching metastable conditions (i.e., CW 52 °C and CW-TP 52 °C) had the highest G′ and yield stress of all organogels investigated. In the same way, creep and recovery analyses showed that CW 52 °C and CW-TP 52 °C organogels had the highest resistance to deformation, lowest instantaneous recovery, and highest extended recovery of all organogels studied. We concluded that application of shear and the extent of its application as a function of supercooling determine crystal size and the proportion of transient to junction zones throughout the three-dimensional crystal network and, therefore, the organogels' rheological properties.     

Characterization of Halanaerobaculum tunisiense gen. nov., sp. nov., a new halophilic fermentative, strictly anaerobic bacterium isolated from a hypersaline lake in Tunisia

A new halophilic anaerobe was isolated from the hypersaline surface sediments of El-Djerid Chott, Tunisia. The isolate, designated as strain 6SANG, grew at NaCl concentrations ranging from 14 to 30%, with an optimum at 20–22%. Strain 6SANG was a non-spore-forming, non-motile, rod-shaped bacterium, appearing singly, in pairs, or occasionally as long chains (0.7–1 × 4–13 μm) and showed a Gram-negative-like cell wall pattern. It grew optimally at pH values between 7.2 and 7.4, but had a very broad pH range for growth (5.9–8.4). Optimum temperature for growth was 42°C (range 30–50°C). Strain 6SANG required yeast extract for growth on sugars. Glucose, sucrose, galactose, mannose, maltose, cellobiose, pyruvate, and starch were fermented. The end products from glucose fermentation were acetate, butyrate, lactate, H₂, and CO₂. The G + C ratio of the DNA was 34.3 mol%. Strain 6SANG exhibited 16S rRNA gene sequence similarity values of 91–92% with members of the genus Halobacteroides, H. halobius being its closest phylogenetic relative. Based on phenotypic and phylogenetic characteristics, we propose that this bacterium be classified as a novel species of a novel genus, Halanaerobaculum tunisiense gen. nov., sp. nov. The type strain is 6SANG^T (=DSM 19997^T = JCM 15060^T).     

Thermovorax subterraneus, gen. nov., sp. nov., a thermophilic hydrogen-producing bacterium isolated from geothermally active underground mine

A thermophilic, rod-shaped, motile, Gram-positive, spore-forming bacterium strain 70B^T was isolated from a geothermally active underground mine in Japan. The temperature and pH range for growth was 50–81°C (optimum 71°C) and 6.2–9.8 (optimum pH 7–7.5), respectively. Growth occurred in the presence 0–2% NaCl (optimum 1% NaCl). Strain 70B^T could utilize glucose, fructose, mannose, mannitol, pyruvate, cellobiose and tryptone as substrates. Thiosulfate was used as electron acceptor. Major whole-cell fatty acids were iso-C_15:0, C_16:0 DMA (dimethyl acetal), C_16:0 and anteiso-C_15:0. The G+C mol% of the DNA was 44.2%. Phylogenetic analysis based on the 16S rRNA gene sequence revealed that the closest relatives of strain 70B^T were Thermosediminibacter oceani DSM 16646^T (94% similarity) and Thermosediminibacter litoriperuensis DSM 16647 (93% similarity). The phenotypic, chemotaxonomic and phylogenetic properties suggest that strain 70B^T represents a novel species in a new genus, for which the name Thermovorax subterraneus gen. nov., sp. nov. is proposed. The type strain of Thermovorax subterraneus is 70B^T (=DSM 21563 = JCM 15541).     

Relationship Between Molecular Structure and Thermo-mechanical Properties of Candelilla Wax and Amides Derived from (<Emphasis Type="Italic">R</Emphasis>)-12-Hydroxystearic Acid as Gelators of Safflower Oil

In this research, we studied the relationship between the molecular structure of (R)-12-hydroxyoctadecanamide, (R)-N-propyl-12-hydroxyoctadecanamide, and (R)-N-octadecyl-12-hydroxyoctadecanamide and the thermo-mechanical properties of their 2% (wt/wt) organogels developed using safflower oil high in oleic acid (HOSFO) as the liquid phase. Candelilla wax (CW), a well-known edible gelling additive whose main component is hentriacontane, also was studied for comparative purposes. The results obtained show that the attractive interactions (i.e., hydrogen bonding and dipolar interactions) between amide groups and between hydroxyl groups present in the amides resulted in organogels with higher melting temperature, heat of melting, and crystallization parameters than those found in the CW organogel. The rheological parameters associated to the strength of the amide or CW-based gels developed in HOSFO (i.e., yield stress and elastic modulus) seem to be associated with the nature of amide groups (i.e., primary or secondary amide) and the increase in the length of the self-assembly molecular unit (i.e., L value determined by X-ray diffraction) and therefore to the extent of London dispersion forces along the hydrocarbon chain. The creep and recovery measurements allowed an evaluation among the internal structures of the different organogels and demonstrated that independent of the hydrogen bonding and dipolar interaction provided by the amide and the hydroxyl groups, the increase in the hydrocarbon chain length results in higher organogel resistance to deformation and higher instant recovery capacity. However, the stabilization of the self-assembly unit through polar groups (i.e., –CONH₂ in HOA) reduces organogel elasticity but provides a higher extended recovery capacity. The results reported in this investigation showed some relationships between gelator structure and the thermo-mechanical properties of low-molecular-mass organic gelator amides. Our long-term objective is to understand the organogelation process to eventually develop trans-free vegetable oil-based food products with novel textures for the consumers.     

<Emphasis Type="Italic">Marinobacter zhanjiangensis</Emphasis> sp. nov., a marine bacterium isolated from sea water of a tidal flat of the South China Sea

A novel Gram-negative, catalase- and oxidase-positive, non-sporulating, rod-shaped, aerobic bacterium, designated strain JSM 078120^T, was isolated from sea water collected from a tidal flat of Naozhou Island, South China Sea. Growth occurred with 1–15% (w/v) total salts (optimum, 2–4%), at pH 6.0–10.0 (optimum, pH 7.5) and at 4–35°C (optimum, 25–30°C). The major cellular fatty acids were C_18:1 ω9c, C_16:0, C_12:0 3-OH and C_16:1 ω7c. The predominant respiratory quinone was ubiquinone Q-9, and the genomic DNA G + C content was 60.6 mol%. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain JSM 078120^T should be assigned to the genus Marinobacter, being related most closely to the type strains of Marinobacter segnicrescens (sequence similarity 98.2%), Marinobacter bryozoorum (97.9%) and Marinobacter gudaonensis (97.6%). The sequence similarities between the novel isolate and the type strains of other recognized Marinobacter species ranged from 96.7 (with Marinobacter salsuginis) to 93.3% (with Marinobacter litoralis). The levels of DNA–DNA relatedness between strain JSM 078120^T and the type strains of M. segnicrescens, M. bryozoorum and M. gudaonensis were 25.3, 20.6 and 18.8%, respectively. The combination of phylogenetic analysis, DNA–DNA relatedness, phenotypic characteristics and chemotaxonomic data supported the view that strain JSM 078120^T represents a novel species of the genus Marinobacter, for which the name Marinobacter zhanjiangensis sp. nov. is proposed. The type strain is JSM 078120^T (= CCTCC AB 208029^T = DSM 21077^T = KCTC 22280^T). The GenBank/EMBL/DDBJ accession number for the 16S rRNA gene sequence of strain JSM 078120^T is FJ425903.     

<Emphasis Type="Italic">Halomonas sediminis</Emphasis> sp. nov., a new halophilic bacterium isolated from salt-lake sediment in China

A novel Gram-negative, slightly halophilic, catalase- and oxidase-positive, obligately aerobic bacterium, strain YIM-C248^T, was isolated from a sediment sample collected from a salt-lake in the Qaidam Basin in Qinghai, north-west China. Cells were non-sporulating short rods, occurring singly or as doublets, motile with peritrichous flagella. Growth occurred with 1–15% (w/v) NaCl [optimum 2–4% (w/v) NaCl], at pH 6.0–10.0 (optimum pH 7.5) and at 4–35°C (optimum 25–30°C). The major cellular fatty acids were C_18:1 ω7c, C_12:0 3-OH, cyclo C_19:0 ω8c, C_16:0 and C_16:1. The predominant respiratory quinone was Q-9 and the genomic DNA G + C content was 58.6 mol%. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain YIM-C248^T should be assigned to the genus Halomonas. The sequence similarities between the isolate and the type strains of members of the genus Halomonas were in the range of 92.5–97.5%. The combination of phylogenetic analysis, DNA–DNA hybridization data, phenotypic characteristics and chemotaxonomic differences supported the view that strain YIM-C248^T represents a new species of the genus Halomonas, for which the name Halomonas sediminis sp. nov. is proposed, with YIM-C248^T (=CCTCC AA 207031 = KCTC 22167) as the type strain. The GenBank/EMBL/DBBJ accession number for the 16S rRNA gene sequence of strain YIM-C248^T is EU135707.     

<Emphasis Type="Italic">Alteromonas halophila</Emphasis> sp. nov., a new moderately halophilic bacterium isolated from a sea anemone

A pale yellow-colored, moderately halophilic, Gram-negative, catalase- and oxidase-positive, non-sporulating, rod-shaped, motile, aerobic bacterium, designated strain JSM 073008^T, was isolated from a sea anemone (Anthopleura xanthogrammica) collected from Naozhou Island, Leizhou Bay, South China Sea. The organism was able to grow with 1–20% (w/v) total salts (optimum, 5–10%), at pH 6.0–10.0 (optimum, pH 7.5) and 10–40°C (optimum, 25–30°C). The major cellular fatty acids were C_16:0, C_16:1 ω7c/iso-C_15:0 2-OH and C_18:1 ω7c. The polar lipids consisted of phosphatidylethanolamine, phosphatidylglycerol and an unidentified phospholipid. The predominant respiratory quinone was Q-8 and the genomic DNA G + C content was 47.5 mol%. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain JSM 073008^T should be assigned to the genus Alteromonas, being most closely related to Alteromonas hispanica F-32^T (sequence similarity 96.9%), followed by Alteromonas genovensis LMG 24078^T (96.6%) and Alteromonas litorea TF-22^T (96.4%). The sequence similarities between the novel isolate and the type strains of other recognized Alteromonas species ranged from 95.9% (with Alteromonas stellipolaris ANT 69a^T) to 94.5% (with Alteromonas simiduii BCRC 17572^T). The combination of phylogenetic analysis, phenotypic characteristics and chemotaxonomic data supported the view that strain JSM 073008^T represents a new species of the genus Alteromonas, for which the name Alteromonas halophila sp. nov. is proposed. The type strain is JSM 073008^T (=CCTCC AA 207035^T = KCTC 22164^T). The authors Yi-Guang Chen and Huai-Dong Xiao have contributed equally to this work.     

Factors influencing the radiative surface temperature of grey seal (<Emphasis Type="Italic">Halichoerus grypus</Emphasis>) pups during early and late lactation

The aim of this study was to examine the variation in body surface temperature of grey seal (Halichoerus grypus) pups throughout lactation in response to different environmental conditions. Radiative surface temperatures (T _r, °C) of pups were measured on the Isle of May (56°11′N, 02°33′W), southeast Scotland from 29 October to 25 November 2003. Records were obtained from a total of 60 pups (32 female and 28 male) from three different pupping sites during early and late lactation. Pups were sheltered from high wind speeds but air temperature, humidity and solar radiation at pupping sites were similar to general meteorological conditions. The mean T _r of all pups was 15.8°C (range 7.7–29.7°C) at an average air temperature of 10.2°C (range 6.5–13.8°C). There was no difference in the mean T _r of pups between early and late lactation. However, the T _r varied between different regions of the body with hind flippers on average 2–6°C warmer than all other areas measured. There was no difference in mean T _r of male and female pups and pup body mass did not account for the variation in T _r during early or late lactation. Throughout the day there was an increase in the T _r of pups and this explained 20–28% of the variation in T _r depending on stage of lactation. There was no difference in the mean T _r of pups between pupping sites or associated with different substrate types. Wind speed and substrate temperature had no effect on the T _r of pups. However, solar radiation, air temperature and relative humidity accounted for 48% of the variation in mean T _r of pups during early lactation. During late lactation air temperature and solar radiation alone accounted for 43% of the variation in T _r. These results indicate that environmental conditions explain only some of the variation in T _r of grey seal pups in natural conditions. Differences in T _r however indicate that the cost of thermoregulation for pups will vary throughout lactation. Further studies examining intrinsic factors such as blubber thickness and activity levels are necessary before developing reliable biophysical models for grey seals.     

Impact of two different types of heat stress on chloroplast movement and fluorescence signal of tobacco leaves

Although the chloroplast movement can be strongly affected by ambient temperature, the information about chloroplast movement especially related to high temperatures is scarce. For detailed investigation of the effects of heat stress (HS) on tobacco leaves (Nicotiana tabacum L. cv. Samsun), we used two different HS treatments in dark with wide range of elevated temperatures (25–45°C). The leaf segments were either linearly heated in water bath at heating rate of 2°C min⁻¹ from room temperature up to maximal temperature (T _m) and then linearly cooled down to 25°C or incubated for 5 min in water bath at the same T _m followed by 5 min incubation at 25°C (T-jump). The changes in light-induced chloroplast movement caused by the HS pretreatment were detected after the particular heating regime at 25°C using a method of time-dependent collimated transmittance (CT) and compared with the chlorophyll O–J–I–P fluorescence rise (FLR) measurements. The inhibition of chloroplast movement started at about 40°C while the fluorescence parameters responded generally at higher T _m. This difference in sensitivity of CT and FLR was higher for the T-jump than for the linear HS indicating importance of applied heating regime. A possible influence of chloroplast movement on the FLR measurement and a physiological role of the HS-impaired chloroplast movement are discussed.     

Characterization of Microaerobacter geothermalis gen. nov., sp. nov., a novel microaerophilic, nitrate- and nitrite-reducing thermophilic bacterium isolated from a terrestrial hot spring in Tunisia

A novel thermophilic anaerobic and microaerophilic bacterium (optimal growth in the presence of 5–10% O₂), strain Nad S1^T was isolated from the terrestrial hot spring of Hammam Sidi Jdidi, Nabeul, Tunisia. Cells were motile rods having a Gram-positive cell wall structure. Strain Nad S1^T grew optimally at 55°C (range 37–70°C). Optimum pH for growth was 6.5–7.0. It was halotolerant growing with NaCl up to 7% (optimum concentration 1.5–3.0%). It grew chemoorganotrophically on various carbohydrates, organic-acids and amino-acids as energy sources, or chemolithotrophically on H₂ using nitrate, as terminal electron acceptor. Beside oxygen (under microaerobic conditions) and nitrate, nitrite was also used. Nitrate was completely reduced to N₂. No fermentation occurred. The genomic DNA G + C content was 41.8 mol%. Based on 16S rRNA gene sequence analysis, strain Nad S1^T belongs to the Bacillaceae family within the class ‘Bacilli’. Because of its phylogenetic and phenotypic characteristics, we propose this isolate to be assigned as a novel genus and a novel species within the domain Bacteria, Microaerobacter geothermalis gen. nov., sp. nov. The type strain is Nad S1^T (=DSM 22679^T =JCM 16213^T).     

Salinity and Temperature Effects on Germination for Three Salt-resistant Euhalophytes, Halostachys caspica, Kalidium foliatum and Halocnemum strobilaceum

The effects of three salinities (0, 100 and 500 mM NaCl) and four constant temperatures (10, 20, 30 and 35 °C) on seed germination of Halostachys caspica (M. B.) C. A. Mey., Kalidium foliatum (Pall.) Mop. and Halocnemum strobilaceum (Pall.) Bieb. were investigated. After seeds were treated with different concentrations of NaCl at constant temperatures of 10–35 °C for 16 days, ungerminated seeds were transferred to distilled water for 10 days to investigate the total germination; after this time, the ungerminated seeds from the 10 and 20 °C treatments were then moved to 35 °C for another 5 days to determine the final germination. The three plant species in the present experiment are salt-resistant euhalophytes growing in high saline soils in the Zhungur Basin in Xinjiang, a northwest province of China.Compared with germination under control conditions, germination percentages of all three species were not affected by 100 mM NaCl at 10–35 °C, while severely inhibited by 500 mM NaCl; germination percentages were very low at 10 °C up to 100 mM NaCl for all species; the optimum temperature for germination of H. caspica and K. foliatum was 20–30 °C, while 35 °C for H. strobilaceum, up to 100 mM NaCl; seeds did not suffer ion toxicity for all species, as evidenced by the high total germination after ungerminated seeds pretreated with 500 mM NaCl were transferred to distilled water at constant temperatures of 10–35 °C for 10 days, and the high final germination after the ungerminated seeds from the 10 and 20 °C treatments were subsequently moved to 35 °C for another 5 days; Halostachys caspica had greater sensitivity to increasing temperatures from 10 and 20 °C to 35 °C compared with the other two species.     

<Emphasis Type="Italic">Arthrobacter halodurans</Emphasis> sp. nov., a new halotolerant bacterium isolated from sea water

A novel Gram-positive, halotolerant, non-sporulating, non-motile, catalase-positive, oxidase-negative and aerobic bacterium, designated strain JSM 078085^T, was isolated from sea water collected from the South China Sea. Strain JSM 078085^T exhibited a rod-coccus growth cycle and produced a yellow pigment. The strain was able to grow in the presence of 0–12% (w/v) NaCl and at pH 6.0–9.5 and 4–35°C; optimum growth was observed at pH 7.0 and 25–30°C in the absence of NaCl. The peptidoglycan type was A4α (l-Lys–l-Ala–l-Glu). Cell-wall sugars contained galactose and glucose. Strain JSM 078085^T contained menaquinone MK-9(H₂) as the major respiratory quinone and diphosphatidylglycerol, phosphatidylglycerol and phosphatidylinositol as the major polar lipids. The major cellular fatty acids were anteiso-C_15:0, iso-C_15:0 and anteiso-C_17:0 and the DNA G + C content was 63.3 mol%. Phylogenetic analysis based on 16S rRNA gene sequence comparisons revealed that strain JSM 078085^T should be assigned to the genus Arthrobacter, being most closely related to the type strain of Arthrobacter rhombi (sequence similarity 97.1%), and the two strains formed a distinct lineage in the phylogenetic tree. The level of DNA–DNA relatedness between strain JSM 078085^T and the type strain of Arthrobacter rhombi was 10.6%. The combination of phylogenetic analysis, DNA–DNA relatedness, phenotypic characteristics and chemotaxonomic data supported the view that strain JSM 078085^T represents a novel species of the genus Arthrobacter, for which the name Arthrobacter halodurans sp. nov. is proposed. The type strain is JSM 078085^T (=DSM 21081^T=KCTC 19430^T). The GenBank/EMBL/DDBJ accession number for the 16S rRNA gene sequence of strain JSM 078085^T is EU583729.     

Oceanibacterium hippocampi gen. nov., sp. nov., isolated from cutaneous mucus of wild seahorses (Hippocampus guttulatus)

A Gram-negative, aerobic, motile and slightly curved rod-shaped bacterium (BFLP-8^T) was isolated from cutaneous mucus of wild long-snouted seahorses (Hippocampus guttulatus) captured in northwest Spain (Toralla, Galicia). Strain BFLP-8^T grew at 10–35 °C and pH 5–9 (optimally at 25 °C and pH 7.0) and with 1–6 % (w/v) NaCl (optimally with 2 % NaCl). The predominant respiratory quinone (90 %) was ubiquinone with ten isoprene units (Q-10) and the major fatty acids identified were C_18:1 ω7c (54.8 % of the total), C_19:0 cyclo ω8c (11.6 %), C_16:0 (9.5 %), C_18:1 2-OH (7.1 %) and C_16:1 ω11c (6.7 %). The G+C content of the DNA was 57.8 mol%. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain BFLP-8^T formed a distinct clade within the family Sneathiellaceae but is not specifically associated with any species in the family. On the basis of phenotypic, chemotaxonomic and phylogenetic data, strain BFLP-8^T represents a novel species within a new genus, for which the name Oceanibacterium hippocampi gen. nov., sp. nov. is proposed. The type strain is BFLP-8^T (=CECT 7691^T = DSM 23444^T).     

Purification and biochemical characterization of a native invertase from the hydrogen-producing Thermotoga neapolitana (DSM 4359)

This is the first report describing the purification and enzymatic properties of a native invertase (β-D-fructosidase) in Thermotogales. The invertase of the hydrogen-producing thermophilic bacterium Thermotoga neapolitana DSM 4359 (hereby named Tni) was a monomer of about 47 kDa having an amino acid sequence quite different from other invertases studied up to now. Its properties and substrates specificity let us classify this protein as a solute-binding protein with invertase activity. Tni was specific for the fructose moiety and the enzyme released fructose from sucrose and raffinose and the fructose polymer inulin was hydrolyzed in an endo-type fashion. Tni had an optimum temperature of 85°C at pH 6.0. At temperatures of 80–85°C, the enzyme retained at least 50% of its initial activity during a 6 h preincubation period. Tni had a K _m and k _cat /K _m values (at 85°C and pH 6.0) of about 14 mM and 5.2 × 10⁸ M⁻¹ s⁻¹, respectively. Dedicated to the memory of Prof. R. A. Nicolaus, founder of the Institute (1968).     

<Emphasis Type="Italic">Halobacillus naozhouensis</Emphasis> sp. nov., a moderately halophilic bacterium isolated from a sea anemone

A moderately halophilic, Gram-positive, catalase- and oxidase-positive, rod-shaped, aerobic bacterium, designated strain JSM 071068^T, was isolated from a sea anemone (Anthopleura xanthogrammica) collected from the Naozhou Island on the Leizhou Bay in the South China Sea. Cells were motile by means of peritrichous flagella and formed ellipsoidal endospores lying in subterminal swollen sporangia. Strain JSM 071068^T was able to grow with 1–20% (w/v) total salts (optimum, 6–9%), at pH values of 6.0–10.0 (optimum, pH 7.5) and a temperature range of 10–35°C (optimum, 25°C). meso-Diaminopimelic acid was present in the cell-wall peptidoglycan. The predominant menaquinone was MK-7 and the major cellular fatty acids were anteiso-C_15:0, anteiso-C_17:0 and iso-C_15:0. The genomic DNA G + C content was 42.8 mol%. Phylogenetic analysis based on 16S rRNA gene sequence comparisons revealed that strain JSM 071068^T belonged to the genus Halobacillus. The 16S rRNA gene sequence similarities between strain JSM 071068^T and the type strains of the recognized Halobacillus species ranged from 97.9% (with Halobacillus alkaliphilus) to 95.3% (with Halobacillus kuroshimensis). The levels of DNA–DNA relatedness between the new isolate and the type strains of H. alkaliphilus, Halobacillus campisalis, Halobacillus halophilus and Halobacillus seohaensis were 25.6, 22.1, 10.8 and 13.2%, respectively. The combination of phylogenetic analysis, DNA–DNA relatedness, phenotypic characteristics and chemotaxonomic data supported the view that strain JSM 071068^T represents a new species of the genus Halobacillus, for which the name Halobacillus naozhouensis sp. nov. is proposed, with JSM 071068^T (=DSM 21183^T =KCTC 13234^T) as the type strain. The GenBank/EMBL/DDBJ accession number for the 16S rRNA gene sequence of strain JSM 071068^T is EU925615.     

Winter body temperature patterns in free-ranging Cape ground squirrel, Xerus inauris: no evidence for torpor

The body temperature (T _b) of Cape ground squirrels (Xerus inauris, Sciuridae) living in their natural environment during winter has not yet been investigated. In this study we measured abdominal T _b of eight free-ranging Cape ground squirrels over 27 consecutive days during the austral winter. Mean daily T _b was relatively stable at 37.0 ± 0.2°C (range 33.4 to 40.2°C) despite a marked variation in globe temperature (T _g) (range −7 to 37°C). Lactating females (n = 2) consistently had a significantly higher mean T _b (0.7°C) than non-lactating females (n = 3) and males. There was a pronounced nychthemeral rhythm with a mean active phase T _b of 38.1 ± 0.1°C and a mean inactive phase T _b of 36.3 ± 0.3°C for non-lactating individuals. Mean daily amplitude of T _b rhythm was 3.8 ± 0.2°C. T _b during the active phase closely followed T _g and mean active phase T _b was significantly correlated with mean active phase T _g (r ² = 0.3–0.9; P < 0.01). There was no evidence for daily torpor or pronounced hypothermia during the inactive phase, and mean minimum inactive phase T _b was 35.7 ± 0.3°C for non-lactating individuals. Several alternatives (including nocturnal huddling, an aseasonal breeding pattern and abundant winter food resources) as to why Cape ground squirrels do not employ nocturnal hypothermia are discussed.     

Selection and characterization of mannanase-producing bacteria useful for the formation of prebiotic manno-oligosaccharides from copra meal

In order to select bacterial strains effectively secreting mannanase activity for the production of prebiotic mannooligosaccharides, a two-step screening procedure was performed. Enriched cultures from isolation medium containing copra meal were primary screened on an isolation agar medium containing 1% locust bean gum (LBG), which resulted in 48 mannanase-producing bacterial isolates with significant clearing zones on the mannan-containing agar. However, only nine isolates showed appreciable mannanase activities against copra meal in their culture supernatants (0.054–0.185 U/mg of protein) as determined in a standard assay based on the detection of reducing sugars released from this substrate. The isolates CW2-3 and ST1-1 displayed the highest activity against LBG and copra meal, respectively. Copra mannan hydrolysates that were obtained by using crude mannanase from these nine isolates were further used for a secondary screening towards a growth-enhancing activity on Lactobacillus reuteri and inhibitory activity against Escherichia coli as well as Salmonella Enteritidis, resulting in 0.09–2.15 log CFU/ml enhancing activity and low inhibitory activity of 0.46–1.78 log CFU/ml as well as 0.37–1.72 log CFU/ml, respectively. The hydrolysate of CW2-3 mannanase showed the highest enhancing activity of 2.15 log CFU/ml while isolate ST1-1 was most effective with respect to growth inhibition against E. coli E010 and S. Enteritidis S003 with 0.76 and 1.61 log CFU/ml, respectively. Based on morphological, physical, biochemical and genetics properties, isolates CW2-3 and ST1-1 were identified as Klebsiella oxytoca and Acinetobacter sp., respectively. Crude mannanase activity from these two strains was characterized preliminarily. The pH optima of mannanase activity from Klebsiella oxytoca CW2-3 and Acinetobacter sp. ST1-1 were 7 and 6, respectively. The enzymes were stable at 4°C over a pH range of 3–6 and 3–10, respectively.     

Hemoglobin senses body temperature

When aspirating human red blood cells (RBCs) into 1.3 μm pipettes (ΔP = −2.3 kPa), a transition from blocking the pipette below a critical temperature T _c = 36.3 ± 0.3°C to passing it above the T _c occurred (micropipette passage transition). With a 1.1 μm pipette no passage was seen which enabled RBC volume measurements also above T _c. With increasing temperature RBCs lost volume significantly faster below than above a T _c = 36.4 ± 0.7 (volume transition). Colloid osmotic pressure (COP) measurements of RBCs in autologous plasma (25°C ≤ T ≤ 39.5°C) showed a T _c at 37.1 ± 0.2°C above which the COP rapidly decreased (COP transition). In NMR T₁-relaxation time measurements, the T₁ of RBCs in autologous plasma changed from a linear (r = 0.99) increment below T _c = 37 ± 1°C at a rate of 0.023 s/K into zero slope above T _c (RBC T₁ transition). In conclusion: An amorphous hemoglobin–water gel formed in the spherical trail, the residual partial sphere of the aspirated RBC. At T _c, a sudden fluidization of the gel occurs. All changes mentioned above happen at a distinct T _c close to body temperature. The T _c is moved +0.8°C to higher temperatures when a D₂O buffer is used. We suggest a mechanism similar to a “glass transition” or a “colloidal phase transition”. At T _c, the stabilizing Hb bound water molecules reach a threshold number enabling a partial Hb unfolding. Thus, Hb senses body temperature which must be inscribed in the primary structure of hemoglobin and possibly other proteins. This article is dedicated to Ludwig Artmann who died on July 21, 2001 on a beautiful summer day during which we performed experiments far away. Ludwig Artmann was a man who encouraged us to be strong and to study hard no matter what were the costs.     

<Emphasis Type="Italic">Halomonas qijiaojingensis</Emphasis> sp. nov. and <Emphasis Type="Italic">Halomonas flava</Emphasis> sp. nov., two moderately halophilic bacteria isolated from a salt lake

Two moderately halophilic, Gram-negative, rod-shaped bacteria, designated YIM 93003^T and YIM 94343^T, were isolated from a salt lake in Xinjiang province, north-west China. The two strains YIM 93003^T and YIM 94343^T grew at 20–40°C, pH 6–9, 0.5–24% (w/v) NaCl and at 20–40°C, pH 6–9, 0.5–23% (w/v) NaCl, respectively. No growth occurred in absence of NaCl. Phylogenetic analyses based on 16S rRNA gene sequences showed that strains YIM 93003^T and YIM 94343^T were phylogenetically affiliated to the genus Halomonas and exhibited sequence similarity of 97.5% and 97.4% to the type strain Halomonas anticariensis DSM 16096^T, respectively. The strains possessed chemotaxonomic markers that were consistent with their classification in the genus Halomonas (Q-9 as predominant respiratory quinine; C18:1ω7c, C16:0 and C16:1 ω7c/iso-C15:02-OH as the major fatty acids). The DNA–DNA hybridization values for strains YIM 93003^T and YIM 94343^T, YIM 93003^T and DSM 16096^T, YIM 94343^T and DSM 16096^T were 38.1 ± 3.0, 18.3 ± 4.7, and 20.8 ± 4.6%, respectively. The G+C contents of the strains YIM 93003^T and YIM 94343^T were 63.4 and 64.0 mol%, respectively. Based on comparative analysis of physiological, biochemical and chemotaxonomic data, including low DNA–DNA hybridization results, two novel species, Halomonas qijiaojingensis sp. nov., and Halomonas flava sp. nov., are proposed. The type strains are YIM 93003^T (=CCTCC AB 208133^T =KCTC 22228^T) and YIM 94343^T (=CCTCC AB 2010382^T =KCTC 23356^T), respectively.     

Zhihengliuella salsuginis sp. nov., a moderately halophilic actinobacterium from a subterranean brine

A novel moderately halophilic, alkaliphilic, non-motile, non-sporulating, catalase-positive, oxidase-negative, aerobic, coccus-shaped, Gram-positive bacterium, designated strain JSM 071043^T, was isolated from a subterranean brine sample collected from a salt mine in Hunan Province, China. Growth occurred with 0.5–20% (w/v) NaCl (optimum 5–10%) at pH 6.5–10.5 (optimum pH 8.5) and at 10–40°C (optimum 25–30°C). Good growth also occurred in the presence of 0.5–20% (w/v) KCl (optimum 5–8%) or 0.5–25% (w/v) MgCl₂·6H₂O (optimum 5–10%). The peptidoglycan type was A4α (l-Lys–l-Ala–l-Glu) and major cell-wall sugars were tyvelose and mannose. The major cellular fatty acids were anteiso-C_15:0, iso-C_16:0 and anteiso-C_17:0. Strain JSM 071043^T contained MK-9 and MK-8 as the predominant menaquinones and diphosphatidylglycerol, phosphatidylglycerol and phosphatidylinositol as the major polar lipids. The DNA G + C content was 67.8 mol%. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain JSM 071043^T was a member of the suborder Micrococcineae, and was most closely related to Zhihengliuella halotolerans YIM 70185^T (sequence similarity 98.9%) and Zhihengliuella alba YIM 90734^T (98.2%), and the three strains formed a distinct branch in the phylogenetic tree. The combination of phylogenetic analysis, DNA–DNA relatedness values, phenotypic characteristics and chemotaxonomic data supports the proposal that strain JSM 071043^T represents a novel species of the genus Zhihengliuella, for which the name Z. salsuginis sp. nov. is proposed. The type strain is JSM 071043^T (= DSM 21149^T = KCTC 19466^T).