Determination of DNA base compositions from melting profiles in dilute buffers

Equations were determined for the dependency of the melting temperature (T_m) of DNA upon the logarithm of the sodium ion concentration, for four DNA samples of widely different base compositions (θ_GC). The slopes of these T_m versus log M equations wore found to decrease with increasing θ_{G C}of the samples. An empirical equation relating T_m, log M (Na⁺) and θ_{G C} was derived, which also accounts for differences in T_m versus log M slopes. Data from the literature for some synthetic polynucleotides and for the crab(Cancer pagarus) satellite poly AT are discussed in relation to the above finding. The changes in T_m versus log M slopes with θ_{G C} are interpreted in terms of changes in the thermodynamic parameters ΔS and ΔH with base composition.     

The structure of triple-stranded G-2C polynucleotide helices.

The thermal stability of a new polynucleotide complex has been used to establish the hydrogen-bonding structure of three-stranded C-G·CH⁺ helices. In the Hoogsteen structure, the 8NH₂ group of 8NH₂GMP can form a third hydrogen bond to the CH⁺ strand, but in the alternative structure, the 8NH₂ group can form no interbase hydrogen bonds. For the new complex, 8NH₂GMP·2 poly(C), a transition temperature of 80°C is observed under conditions in which the corresponding complex formed with 5′-GMP has a T_m of 20°C. We conclude from this 60° elevation of transition temperature that a third hydrogen bond is formed by the 8NH₂ group and that the structure must have Hoogsteen bonding. In order to be compatible with this structure in regular helices formed by U,C copolymers, A·2U bonding would also have to have a Hoogsteen structure.     

Cooperative nonenzymic base recognition II. thermodynamics of the helix-coil transition of oligoadenylic + oligouridylic acids

The properties of oligonucleotide helices of adeuylic- and uridylic acid oligomers have been investigated by measurements of hypo-and hyperchromieity. High ionic strengths favor the formation of triple helices. Thus, the double helix-coil transition can be studied (without interference by triple helices) only at low ionic-strength. A “phase diagram” is given representing the T_m-values of the various transitions at different ionic strengths for the system A(pA)₁₇ + U(pU)₁₇. Oligonucleolides of chain lengths <8 always form both double and triple helices at the nucleotide concentrations required for base pairing. For this reason the double helix-coil transition without coupling of the triple helix equilibrium can only be measured for chain lengths higher than 7. Melting curves corresponding to this transition have been determined for chain lengths 8, 9, 10, 11, 14 and 18 at different concentrations. An increase in nucleotide concentration leads to an increase in melting temperature. The shorter the chain length the lower the T_m-value and the broader the helix-coil transition. The experimental transition curves have been analysed according to a staggering zipper model with consideration of the stacking of the adeuylic acid single strands and the electrostatic repulsion of tlip phosphate charges on opposite strands. The temperature dependence of the nucleation parameter has been accounted for by a slacking factor x. The stacking factor expresses the magnitude of the stacking enthalpy. By curve fitting xwas computed to be 0.7, corresponding to a stacking enthalpy of about S kcal/mole. The model described allows the reproduction of the experimental transition curves with relatively high accuracy. In an appendix the thermodynamic parameters of the stacking equilibrium of poly A and of the helix-coil equilibria of poly A + poly U at neutral pH are calculated (ΔH_A = ?7.9 kcal/mole for the poly A stacking and ΔH₁₂ = ?10.9 kcal/mole for the formation of the double helix from the randomly coiled single strands). A formula for the configurational entropy of polymers derived by Flory on the basis of a liquid lattice model is adapted to calculate the stacking entropies of adenylic oligomers.     

Foam behavior of biological media

Summary The concentration dependence of the foaming of aqueous bovine serum albumin (BSA) solutions with and without salt additives and that of the turbidity temperature, T_T, of p-isononylphenol-10-glycolether in presence of KCl, MgSO₄, or K₄ [Fe(CN)₆] were determined. The differences between the turbidity temperatures of the solutions with and without salt additives were used to calculate the apparent concentration BSA in the salt solutions and to estimate their foaming. The measured and calculated foaminesses agree well.Symbols BSA Bovine Serum Albumin - C concentration - C_BSA concentration of BSA - C_salt salt concentration - C_O actual protein concentration in the absence of a salt - C₁ apparent protein concentration in the presence of a salt - C' NP-10 concentration - k constant in Eq. (4) - T_corr correction for T_TO of the salt-free NP-10 solution - T_T turbidity temperature - V_s equilibrium volume of the foam above the liquid layer - V_tg volumetric gas flow rate - foaminess - NP-10 p-isononylphenol-10-glycolether     

Correlation of Tm,sequence, and ΔH of complementary RNA helices and comparison with DNA helices

T_m values of 16 fully complementary RNA duplexes with repeating base sequence have been employed as the empirical basis for developing a reliable and practical method for computing apparent enthalpies (ΔH _calc) for their helix → coil transitions. The approach taken is the same as in the accompanying investigation of DNA duplexes, although some of the computational variables of the “best-fit” function are necessarily different due to the distinguishing structural properties of the RNA-type helix. An excellent linear correlation was thus obtained between experimental T_m and ΔH _calc values. An equally good fit was obtained between T_m and ΔH _calc for five unrelated (to the 16 RNAs) decaribonucleotide duplexes. The differences in computational variables between the best-fit methods for RNA and DNA duplexes are shown to be a reflection of differences in cation binding and the effective local dielectric. The greater T_m dependence on G·C content of RNA helices than of DNA helices is shown to be due to a greater latitude of stacking stabilities of complementary dinucleotide fragments containing A·T than A·U base pairs.     

Characterization of the hidden glass transition of amorphous cyclomaltoheptaose

An amorphous solid of cyclomaltoheptaose (β-cyclodextrin, β-CD) was formed by milling its crystalline form using a high-energy planetary mill at room temperature. The glass transition of this amorphous solid was found to occur above the thermal degradation point of the material preventing its direct observation and thus its full characterization. The corresponding glass transition temperature (T_g) and the ΔC_p at T_g have, however, been estimated by extrapolation of T_g and ΔC_p of closely related amorphous compounds. These compounds include methylated β-CD with different degrees of substitution and molecular alloys obtained by co-milling β-CD and methylated β-CD (DS 1.8) at different ratios. The physical characterization of the amorphous states have been performed by powder X-ray diffraction and differential scanning calorimetry, while the chemical integrity of β-CD upon milling was checked by NMR spectroscopy and mass spectrometry.     

Estimating heat tolerance among plant species by two chlorophyll fluorescence parameters

The heat tolerance of 8 temperate- and 1 subtropical-origin C₃ species as well as 17 tropical-origin ones, including C₃, C₄, and CAM species, was estimated using both F₀-T curve and the ratio of chlorophyll fluorescence parameters, prior to and after high temperature treatment. When leaves were heated at the rate of ca. 1 °C min⁻¹ in darkness, the critical temperature (T_c) varied extensively among species. The T_c's of all 8 temperate-origin species ranged between 40–46 °C in winter (mean temperature 16–19 °C), and between 32–48 °C in summer (mean temperature ca. 30 °C). Those for 1 subtropical- and 12 tropical-origin C₃ species ranged between 25–44 °C and 35–48 °C, and for 1 CAM and 4 C₄ species were 41–47 and 45–46 °C, respectively. Acclimating three C₃ herbaceous plants at high temperature (33/28 °C, day/night) for 10 d in winter caused their T_c's rising to nearly the values measured in summer. When leaves were exposed to 45 °C for 20 min and then kept at room temperature in darkness for 1 h, a significant correlation between RF_v/m (the ratio of F_v/F_m before and after 45 °C treatment) and T_c was observed for all tested temperate-origin C₃ species as well as tropical-origin CAM and C₄ species. However, F₀ and F_v/F_m of the tropical-origin C₃ species were less sensitive to 45 °C treatment, regardless of a large variation of T_c; thus no significant correlation was found between their RF_v/m and T_c. Thus T_c might not be a suitable index of heat tolerance for plants with wide range of environmental adaptation. Nevertheless, T_c's of tropical origin C₃ species, varying and showing high plasticity to seasonal changes and temperature treatment, appeared suitable for the estimation of the degree of temperature acclimation in the same species.     

A new class of clear mutants from coliphage 434 hy not complementing CII and C3 mutants for lysogenization

Summary Clear mutants which differ from regular C _I , C _II , CIIIand y mutants have been isolated from phage 434 hy. These mutants resemble C _I mutants in plaque and spot phenotype but efficiently complement C _I mutants for lysogenization. Like C _II mutants, they do not complement authentic C _II mutants for lysogenization but in contrast to C _II mutants they also fail to complement C _III mutants. They map between the lambda-434 non-homology region and Co ₁ (aC _II mutant). On account of this map position adjacent to C _II the mutants of the new type are called C _IIa . They arise from phage 434 hy with a frequency comparable to that of C _I and C _II mutants. Such mutants are also obtained from phage lambda but apparently not from phage b₅. C _IIa mutants would not fit into a picture of three independently acting cistrons C _I , C_II, and C _III . The hypothesis is presented that C _IIa and C _II mutants are in the same structural gene. Two possibilities are discussed that would account for the complementation patterns: 1. C _IIa mutants may block the expression of gene C _III in cis position; or 2. the products of genes C _II and C _III function through an oligomeric complex they form.     

Salt glands of recretohalophyte Tamarix under salinity: Their evolution and adaptation

Here, we studied the evolution of salt glands in 11 species of Tamarix and determined their role in adaptation to saline environments by measuring the effect of NaCl on plant growth and salt gland characteristics. Cluster analysis divided Tamarix species into three types (types I–III) according to salt‐gland characteristics. A phylogenetic tree based on ITS sequences indicated an evolutionary relationship consistent with the geographical distribution of Tamarix. We measured growth under different NaCl conditions (0, 100, 200, and 300 mM) for 40 days in three species (T. gallica, T. ramosissima, and T. laxa) representing the three Tamarix types. With increasing NaCl concentration, the biomass of all species was significantly reduced, especially that of T. gallica. Salt secretion ability and salt‐gland density showed similar trends in three types. The order of salt tolerance was type I > type II > type III. We conclude that during Tamarix adaptation to salinity, salt‐gland evolution followed two directions: one increasing salt‐gland density, and the other increasing salt secretion rate per salt‐gland. This study provides a basis for potential mechanisms of recretohalophyte adaptation to salinity.     

On the hydration of DNA. I. Preferential hydration and stability of DNA in concentrated trifluoroacetate solution

The hydration of DNA is an important factor in the stability of its secondary structure. Methods for measuring the hydration of DNA in solution and the results of various techniques are compared and discussed critically. The buoyant density of native and denatured T-7 bacteriophage DNA in potassium trifluoroacetate (KTFA) solution has been measured as a function of temperature between 5 and 50°C. The buoyant density of native DNA increased linearly with temperature, with a dependence of (2.3 ± 0.5) × 10^?4 g/cc-°C. DNA which has been heat denatured and quenched at 0°C in the salt solution shows a similar dependence of buoyant density on temperature at temperatures far below the T_m, and above the T_m. However, there is an inflection region in the buoyant density versus T curve over a wide range of temperatures below the T_m. Optical density versus temperature studies showed that this is due to the. inhibition by KTFA of recovery of secondary structure on quenching. If the partial specific volume is assumed to be the same for native and denatured DNA, the loss of water of hydration on denaturation is calculated to be about 20% in KTFA at a water activity of 0.7 at 25°C. By treating the denaturation of DNA as a phase transition, an equation has immmi derived relating the destabilizing effect of trifluoroacetate to the loss of hydration on denaturation. The hydration of native DNA is abnormally high in the presence of this anion, and the loss of hydration on denaturation is greater than in CsCl. In addition, trifluoroacetate appears to decrease the ΔHof denaturation.     

Nisaea sediminum sp. nov., a heavy metal resistant bacterium isolated from marine sediment in the East China Sea

A Gram-negative, rod-shaped, motile and strictly aerobic bacterium, designated NBU1469^T, was isolated from marine sediment sampled on Meishan Island located in the East China Sea. Strain NBU1469^T grew optimally at temperature of 40 °C, NaCl concentration of 2.0% (w/v) and pH 7.5. Catalase and oxidase activities, H₂S production, nitrate reduction and hydrolysis of Tween 20 were positive. Indole, methyl red reaction, urease, hydrolysis of gelatin, starch, casein, Tweens 40, 60 and 80 were negative. The major cellular fatty acids were C_16:0, C_19:0 cyclo ω8c and summed feature 8 (C_18:1 ω7c and/or C_18:1 ω6c). The only respiratory quinone was ubiquinone-10 (Q-10). The major polar lipids were phosphatidylglycerol, two unidentified amino-phospholipids and two unidentified phospholipids. Comparative analysis of the 16S rRNA gene sequence showed highest similarities to the species with validated name Nisaea nitritireducens DR41_18^T (98.1%) and Nisaea denitrificans DR41_21^T (97.6%). Phylogenetic analyses indicated that strain NBU1469^T formed a distinct lineage with strains Nisaea nitritireducens DR41_18^T and Nisaea denitrificans DR41_21^T within the genus Nisaea. The average nucleotide identity and digital DNA-DNA hybridization values between strain NBU1469^T and related species of genus Nisaea were well below the threshold limit for prokaryotic species delineation. The DNA G?+?C content was 63.6%. Based on its phenotypic, chemotaxonomic and genotypic data, strain NBU1469^T is considered to be a representative of a novel species in the genus Nisaea, for which the name Nisaea sediminum sp. nov. is proposed. The type strain is NBU1469^T (=KCTC 82224 ^T?=MCCC 1K04763^T).

     

Effects of temperature on the properties of primary auditory fibres of the spectacled caiman,Caiman crocodilus (L.)

Summary The effect of temperature on the response properties of primary auditory fibres in caiman was studied. The head temperature was varied over the range of 10–35 ° C while the body was kept at a standard temperature of 27 °C (T_s). The temperature effects observed on auditory afferents were fully reversible. Below 11 °C the neural firing ceased.The mean spontaneous firing rate increased nearly linearly with temperature. The slopes in different fibres ranged from 0.2–3.5 imp s^–1 °C^–1. A bimodal distribution of mean spontaneous firing rate was found (<20 imp s^–1 and >20 imp s^–1 at T_s) at all temperatures.The frequency-intensity response area of the primary fibres shifted uniformly with temperature. The characteristic frequency (CF) increased nearly linearly with temperature. The slopes in different fibres ranged from 3–90 Hz °C^–1. Expressed in octaves the CF-change varied in each fibre from about O.14oct °C^–1 at 15 °C to about 0.06 oct °C^–1 at 30 °C, irrespective of the fibre's CF at T_s. Thresholds were lowest near T_s. Below T_s the thresholds decreased on average by 2dB°C^–1, above T_s the thresholds rose rapidly with temperature. The sharpness of tuning (Q_10db) showed no major change in the temperature range tested.Comparison of these findings with those from other lower vertebrates and from mammals shows that only mammalian auditory afferents do not shift their CF with temperature, suggesting that a fundamental difference in mammalian and submammalian tuning mechanisms exists. This does not necessarily imply that there is a single unifying tuning mechanism for all mammals and another one for non-mammals.Abbreviations BF best frequency: frequency of maximal response at an intensity 10 dB above the CF-threshold - CF characteristic frequency - FTC frequency threshold curve, tuning curve - T _s standard temperature of 27 °C     

Capacity for sustained terrestrial locomotion in an insect: Energetics,thermal dependence,and kinematics

Summary The capacity for sustained, terrestrial locomotion in the cockroach. Blaberus discoidalis, was determined in relation to running speed, metabolic cost, aerobic capacity, and ambient temperature (T _a=15, 23, and 34°C; acclimation temperature=24°C). Steady-state thoracic temperature (T _tss) increased linearly with speed at each T _a.The difference between T _tss and T _awas similar at each experimental temperature with a maximum increase of 7°C. Steady-state oxygen consumption (VO_2ss) increased linearly with speed at each T _aand had a low thermal dependence (Q₁₀=1.0-1.4). The minimum cost of locomotion (the slope of the VO_2ss versus speed function) was independent of T _a.Cockroaches attained a maximal oxygen consumption (VO_2max). increased with T _afrom 2.1 ml O₂·g^-1·h^-1 at 15°C to 4.9 ml O₂·g^-1·h^-1 at 23°C, but showed no further increase at 34°C, VO_2max increased 23-fold over resting VO₂ at 23°C, 10-fold at 34°C, and 15-fold at 15°C. Endurance correlated with the speed at which VO_2max was attained (MAS, maximal aerobic speed). Temperature affected the kinematics of locomotion. compared to cockroaches running at the same speed, but higher temperatures (23–34°C), low temperature (15°C) increased protraction time, reduced stride frequency, and reduced stability by increasing body pitching. The thermal independence of the minimum cost of locomotion (C_min), the low thermal dependence of VO_2ss (i.e., y-intercept of the VO_2ss versus speed function), and a typical Q₁₀ of 2.0 for VO_2max combined to increase MAS and endurance in B. discoidalis when T _awas increased from 15 to 23°C. Exerciserelated endothermy enabled running cockroaches to attain a greater VO_2max, metabolic scope, and endurance capacity at 23°C than would be possible if T _tss remained equal to T _a. The MAS of B. discoidalis was similar to that of other arthropods that use trachea, but was 2-fold greater than ectotherms, such as salamanders, frogs, and crabs of a comparable body mass.Abbreviations T _a ambient temperature - T _t thoracic temperature - T _tss steady state thoracic temperature during exercise - T _trest thoracic temperature during rest - VO₂ oxygen consumption - VO_2rest oxygen consumption during rest - VO_2ss steady-state oxygen consumption during exercise - VO_2max maximal oxygen consumption; MAS maximum aerobic speed - C _min minimum cost of locomotion - t _end endurance time     

Microbacterium suwonense sp. nov., isolated from cow dung

An actinomycete strain, designated M1T8B9^T, was isolated from cow dung in Suwon, Republic of Korea. The isolate was a Gram-positive, nonmotile, and non-spore-forming bacterium. Phylogenetic evaluation based on 16S rRNA gene sequence similarity showed that this isolate belongs to the genus Microbacterium, with its closest neighbors being Microbacterium soli DCY17^T (98.2%) and Microbacterium esteraromaticum DSM 8609^T (98.0%). The polar lipid pattern consisted of diphosphatidylglycerol, phosphatidylglycerol, and one unknown glycolipid. Strain M1T8B9^T contained the major fatty acids C_15:0 anteiso, C_16:0 iso, C _17:0 anteiso, and C_15:0 iso, and the cell-wall peptidoglycan was of type B2β. According to DNA-DNA hybridization studies, strain M1T8B9^T showed 42% and 26% relatedness with M. soli DCY17^T and M. esteraromaticum DSM 8609^T, respectively. On the basis of the data presented, strain M1T8B9^T is considered to represent a novel species of the genus Microbacterium, for which the name Microbacterium suwonense sp. nov. is proposed. The type strain is M1T8B9^T (=KACC 14058^T =NBRC 106310^T).     

Enhanced resistance to stripe rust disease in transgenic wheat expressing the rice chitinase gene RC24

Stripe rust is a devastating fungal disease of wheat worldwide which is primarily caused by Puccinia striiformis f. sp tritici. Transgenic wheat (Triticum aestivum L.) expressing rice class chitinase gene RC24 were developed by particle bombardment of immature embryos and tested for resistance to Puccinia striiformis f.sp tritici. under greenhouse and field conditions. Putative transformants were selected on kanamycin-containing media. Polymease chain reaction indicated that RC24 was transferred into 17 transformants obtained from bombardment of 1,684 immature embryos. Integration of RC24 was confirmed by Southern blot with a RC24-labeled probe and expression of RC24 was verified by RT-PCR. Nine transgenic T₁ lines exhibited enhanced resistance to stripe rust infection with lines XN8 and BF4 showing the highest level of resistance. Southern blot hybridization confirmed the stable inheritance of RC24 in transgenic T₁ plants. Resistance to stripe rust in transgenic T₂ and T₃ XN8 and BF4 plants was confirmed over two consecutive years in the field. Increased yield (27–36 %) was recorded for transgenic T₂ and T₃ XN8 and BF4 plants compared to controls. These results suggest that rice class I chitinase RC24 can be used to engineer stripe rust resistance in wheat.     

Protein-restricted maternal diet during lactation decreases type I and type III tropocollagen synthesis in the skin of mice offspring

We investigated the effects of a low protein (LP) maternal diet during lactation on type I and III tropocollagen synthesis in infant mouse skin. The LP diet decreased the levels of type I and III tropocollagen proteins and COL1A1 and COL3A1 mRNA. Thus, the protein composition of the maternal perinatal diet may influence the skin health of offspring.     

Dynamics of a truncated prion protein,PrP(113–231), from 15N NMR relaxation: Order parameters calculated and slow conformational fluctuations localized to a distinct region

Prion diseases are associated with the misfolding of the prion protein (PrP^C) from a largely α‐helical isoform to a β‐sheet rich oligomer (PrP^Sc). Flexibility of the polypeptide could contribute to the ability of PrP^C to undergo the conformational rearrangement during PrP^C–PrP^Sc interactions, which then leads to the misfolded isoform. We have therefore examined the molecular motions of mouse PrP^C, residues 113–231, in solution, using ¹⁵N NMR relaxation measurements. A truncated fragment has been used to eliminate the effect of the 90‐residue unstructured tail of PrP^C so the dynamics of the structured domain can be studied in isolation. ¹⁵N longitudinal (T₁) and transverse relaxation (T₂) times as well as the proton‐nitrogen nuclear Overhauser effects have been used to calculate the spectral density at three frequencies, 0, ω_N, and 0.87ω_H. Spectral densities at each residue indicate various time‐scale motions of the main‐chain. Even within the structured domain of PrP^C, a diverse range of motions are observed. We find that removal of the tail increases T₂ relaxation times significantly indicating that the tail is responsible for shortening of T₂ times in full‐length PrP^C. The truncated fragment of PrP has facilitated the determination of meaningful order parameters (S²) from the relaxation data and shows for the first time that all three helices in PrP^C have similar rigidity. Slow conformational fluctuations of mouse PrP^C are localized to a distinct region that involves residues 171 and 172. Interestingly, residues 170–175 have been identified as a segment within PrP that will form a steric zipper, believed to be the fundamental amyloid unit. The flexibility within these residues could facilitate the PrP^C–PrP^Sc recognition process during fibril elongation.     

High‐Performance Electrocatalytic Conversion of N2 to NH3 Using Oxygen‐Vacancy‐Rich TiO2 In Situ Grown on Ti3C2Tx MXene

To achieve the energy‐effective ammonia (NH₃) production via the ambient‐condition electrochemical N₂ reduction reaction (NRR), it is vital to ingeniously design an efficient electrocatalyst assembling the features of abundant surface deficiency, good dispersibility, high conductivity, and large surface specific area (SSA) via a simple way. Inspired by the fact that the MXene contains thermodynamically metastable marginal transition metal atoms, the oxygen‐vacancy‐rich TiO₂ nanoparticles (NPs) in situ grown on the Ti₃C₂T_x nanosheets (TiO₂/Ti₃C₂T_x) are prepared via a one‐step ethanol‐thermal treatment of the Ti₃C₂T_x MXene. The oxygen vacancies act as the main active sites for the NH₃ synthesis. The highly conductive interior untreated Ti₃C₂T_x nanosheets could not only facilitate the electron transport but also avoid the self‐aggregation of the TiO₂ NPs. Meanwhile, the TiO₂ NPs generation could enhance the SSA of the Ti₃C₂T_x in return. Accordingly, the as‐prepared electrocatalyst exhibits an NH₃ yield of 32.17 µg h^?1 mg^?1_cat. at ?0.55 V versus reversible hydrogen electrode (RHE) and a remarkable Faradaic efficiency of 16.07% at ?0.45 V versus RHE in 0.1 m HCl, placing it as one of the most promising NRR electrocatalysts. Moreover, the density functional theory calculations confirm the lowest NRR energy barrier (0.40 eV) of TiO₂ (101)/Ti₃C₂T_x compared with Ti₃C₂T_x or TiO₂ (101) alone.     

Studies on the biosynthesis of TMV

Summary Heating of the TMV replicative form (RF) above a certain temperature (T _m)causes a sharp shift from RNase resistance to sensitivity. The T _mwas determined at different salt concentrations and in the presence of formamide.The kinetics of the annealing reaction between TMV RNA and its complementary RNA was studied, and the rate constant was estimated. Under the chosen conditions which are appropriate for annealing, no dissociation of double-stranded TMV RNA was detected. The kinetic data permitted a maximum estimate of the equilibrium constant of the annealing (or dissociation) reaction.     

<Emphasis Type="Italic">Oceanicoccus sagamiensis</Emphasis> gen. nov., sp. nov., a gammaproteobacterium isolated from sea water of Sagami Bay in Japan

A gram-negative, motile, coccoid- and amorphous-shaped, non-pigmented chemoheterotrophic bacterium, designated strain PZ-5^T, was isolated from sea water of Sagami Bay in Japan and subjected to a polyphasic taxonomic study. Phylogenetic analysis based on 16S rRNA gene sequences revealed that the novel isolate could be affiliated with the class Gammaproteobacteria. Strain PZ-5^T showed below 93.9% similarity with validly published bacteria and demonstrated the highest sequence similarity to Dasania marina KOPRI 20902^T (93.9%). Strain PZ-5^T formed a monophyletic group with D. marina KOPRI 20902^T. The DNA G+C content of strain PZ-5^T was 49.8 mol%. The major isoprenoid quinone was Q-8 and predominant cellular fatty acids were C_15:0 ISO 20H (19%), C_16:1 ω7c (17.4%), C_17;1 ω8c (16.2%), C_11:0 3OH (7.5%), and C_15:1 ω8c (6.5%). Based on evidence from a polyphasic taxonomical study, it was concluded that the strain should be classified as representing a new genus and species of the class Gammaproteobacteria, for which the name Oceanicoccus sagamiensis gen. nov., sp. nov., (type strain PZ-5^T =NBRC 107125^T =KCTC 23278^T) is proposed.