Comparative aspects of the thermal biology of the short-tailed gerbil, Desmodillus auricularis, and the bushveld gerbil, Tatera leucogaster

1. 1. The response of oxygen consumption (VO₂), thermal conductance (C_d and C_min, body temperature (T_b), and evaporative water loss (EWL) of Tatera leucogaster and Desmodillus auricularis were measured over the range of ambient temperatures (T_a) from 5–35°C.

2. 2. Basal metabolic rate (BMR) of T. leucogaster was 0.841 ± 0.049 ml O₂ g⁻¹ h⁻¹ and lower than predicted, while that of D. auricularis was similar to the expected value (1.220 ± 0.058 ml O₂ g⁻¹ h⁻¹). D. auricularis had a high, narrow thermoneutral zone (TNZ) typical of nocturnal, xerophilic, burrowing rodents.

3. 3. D. auricularis and T. leucogaster regulated T_b over the range T_a = 5–35°C and kept EWL and dry thermal conductance at a minimum below the TNZ. However, the EWL of T. leucogaster increased rapidly above T_a = 30°C.

4. 4. After comparison with data from other species, it was concluded that there is an optimum size for xeric, nocturnal, burrowing rodents.

Photosynthetic response of Myriophyllum salsugineum A.E. orchard to photon irradiance, temperature and external free CO2

The photosynthetic capacity of Myriophyllum salsugineum A.E. Orchard was measured, using plants collected from Lake Wendouree, Ballarat, Victoria and grown subsequently in a glasshouse pond at Griffith, New South Wales. At pH 7.00, under conditions of constant total alkalinity of 1.0 meq dm⁻³ and saturating photon irradiance, the temperature optimum was found to be 30–35°C with rates of 140 μmol mg⁻¹ chlorophyll a h⁻¹ for oxygen production and 149 μmol mg⁻¹ chlorophyll a h⁻¹ for consumption of CO₂. These rates are generally higher than those measured by other workers for the noxious Eurasian water milfoil, Myriophyllum spicatum L., of which Myriophyllum salsugineum is a close relative. The light-compensation point and the photon irradiance required to saturate photosynthetic oxygen production were exponentially dependent on water temperature. Over the temperature range 15–35°C the light-compensation point increased from 2.4 to 16.9 μmol (PAR) m⁻² s⁻¹ for oxygen production while saturation photon irradiance increased from 41.5 to 138 μmol (PAR) m⁻² s⁻¹ for oxygen production and from 42.0 to 174 μmol (PAR) m⁻² s⁻¹ for CO₂ consumption. Respiration rates increased from 27.1 to 112.3 μmol (oxygen consumed) g⁻¹ dry weight h⁻¹ as temperature was increased from 15 to 35°C. The optimum temperature for productivity is 30°C.     

Germination, Radial Growth, and Sporulation of Beauveria bassiana and Metarhizium anisopliae Isolates and Their Virulence to Chilo partellus (Lepidoptera: Pyralidae) at Different Temperatures

The effect of temperature regimes on conidia germination, radial growth and virulence of Beauveriabassiana and Metarhizium anisopliae against the spotted stalk borer Chilo partellus was investigated with Ethiopian isolates. Conidia germination, radial growth and sporulation of all isolates were retarded at 15 and 35°C. A suitable temperature range for the isolates was between 20 to 30°C. Conidia germination was less tolerant of low temperature (15°C) than radial growth. Radial growth and sporulation reacted differently to temperature. At both 25 and 30°C, all isolates induced 100% mortality to C. partellus larvae in six days. The LT₅₀ decreased for the isolates with increasing temperature.     

Nutrient removal by thermophilic Fischerella (Mastigocladus laminosus) in a simulated algaculture process

A novel nutrient removal/waste heat utilization process was simulated using semicontinuous cultures of the thermophilic cyanobacterium Fischerella. Dissolved inorganic carbon (DIC)-enriched cultures, maintained with 10 mg l⁻¹ daily productivity, diurnally varying temperature (from 55°C to 26–28°C), a 12:12 light cycle (200 μE sec⁻¹ m⁻²) and 50% biomass recycling into heated effluent at the beginning of each light period, removed > 95% of NO₃⁻ + NO₂⁻−N, 71% of NH₃-N, 82% of PO₄³⁻ −P, and 70% of total P from effluent water samples containing approximately 400 μg l⁻¹ combined N and 60 μg l⁻¹ P. Nutrient removal was not severely impaired by an altered temperature gradient, doubled light intensity, or DIC limitation. Recycling 75% of the biomass at the end of each light period resulted in unimpaired NO₃⁻ + NO₂⁻ removal, 38–45% P removal and no net NH₃ removal. Diurnally varying P removal, averaging 50–60%, and nearly constant > 80% N removal, are therefore projected for a full-scale process with continuous biomass recycling.     

Influence of phosphorus concentration on the growth kinetics and stoichiometry of the microalga Scenedesmus obliquus

The growth of the freshwater microalga Scenedesmus obliquus was studied at 30°C in a mineral culture medium with phosphorus concentrations of between 0 and 372 μ . The values for the specific growth rates, between and , fitted a semistructured substrate-limitation model with μ_m1 = 0·0466 h⁻¹, μ_m2 = 0·0256 h⁻¹ and . The specific uptake rate of phosphorus reached a maximum value of q_Sm1 = 658·01 × 10⁻⁴ μmol P mg⁻¹ biomass h⁻¹.     

The respiratory chain of Azotobacter vinelandii II. The effect of cyanide on cytochrome d

1. Cyanide causes a slow disappearance of the oxidized band (648 nm) of cytochrome d in particles of Azotobacter vinelandii and inhibits the appearance of the reduced band (631 nm). No effect of cyanide is found on the reduced band of cytochrome d.

2. The kinetics of the disappearance of the 648-nm band of cytochrome d with excess cyanide deviates from first-order kinetics at lower temperatures (22 °C) indicating that at least two conformations of the enzyme are involved. At higher temperatures (32 °C) the observed kinetics of the cyanide reaction are first order with a k_on = 0.7 M⁻¹·s⁻¹ and with an estimated k_off of approximately 5·10⁻⁵ s⁻¹.

3. The value of the k_off (7·10⁻⁴−14·10⁻⁴ s⁻¹ at 32 °C) determined from the rate of reduction of cyanocytochrome d by Na₂S₂O₄ or NADH is one order of magnitude larger than the k_off value found when the enzyme is in its oxidized state.

4. No effect of cyanide is found on the spectrum of cytochrome a₁.     

The reaction between the superoxide anion radical and cytochrome c

1. 1. The superoxide anion radical (O₂⁻) reacts with ferricytochrome c to form ferrocytochrome c. No intermediate complexes are observable. No reaction could be detected between O₂⁻ and ferrocytochrome c.

2. 2. At 20 °C the rate constant for the reaction at pH 4.7 to 6.7 is 1.4 · 10⁶ M⁻¹ · s⁻¹ and as the pH increases above 6.7 the rate constant steadily decreases. The dependence on pH is the same for tuna heart and horse heart cytochrome c. No reaction could be demonstrated between O₂⁻ and the form of cytochrome c which exists above pH ≈ 9.2. The dependence of the rate constant on pH can be explained if cytochrome c has pKs of 7.45 and 9.2, and O₂⁻ reacts with the form present below pH 7.45 with k = 1.4 · 10⁶ M⁻¹ · s⁻¹, the form above pH 7.45 with k = 3.0 · 10⁵ M⁻¹ · s⁻¹, and the form present above pH 9.2 with k = 0.

3. 3. The reaction has an activation energy of 20 kJ mol⁻¹ and an enthalpy of activation at 25 °C of 18 kJ mol⁻¹ both above and below pH 7.45. It is suggested that O₂⁻ may reduce cytochrome c through a track composed of aromatic amino acids, and that little protein rearrangement is required for the formation of the activated complex.

4. 4. No reduction of ferricytochrome c by HO₂ radicals could be demonstrated at pH 1.2–6.2 but at pH 5.3, HO₂ radicals oxidize ferrocytochrome c with a rate constant of about 5 · 10⁵–5 · 10⁶ M⁻¹ · s⁻¹

.     

Growth and photosynthesis of Hydrocotyle ranunculoides L. fil. in Central Europe

Floating Pennywort (Hydrocotyle ranunculoides L. fil.) is a worldwide distributed aquatic plant. The species is native to North America and quite common also in Central and South America. In Europe, Japan and Australia it is known as an alien plant, sometimes causing serious problems for affected ecosystems and human use of water bodies. Starting from Western Europe with an eastwards directed spread, Floating Pennywort was recorded in Germany in 2004 for the first time. Since then, the species spread out and got established in western parts of Central Europe. For a definite prediction of the potential of a further spread, data about biology, in particular growth and photosynthesis are needed. Here, regeneration capacity, growth at different nutrient availabilities and photosynthesis of H. ranunculoides were investigated. In addition biomass samples were taken in the field. Results show an enormous regeneration capacity (e.g., by forming new shoots from small shoot fragments), increasing growth rates under increasing nutrient availability and a maximum increase of biomass reaching 0.132±0.008 g g⁻¹ dw d⁻¹. Dense populations of H. ranunculoides growing in ponds and oxbows were found at high nutrient content of the substrate, the biomass reaching there up to 532.4±14.2 g dw m⁻². Gas exchange analysis showed a physiological optimum of H. ranunculoides CO₂ uptake at temperatures between 25 and 35 °C and high photon flux densities (PPFD) above 800 μmol photons m⁻² s⁻¹. In comparison, native Hydrocotyle vulgaris showed an optimum of net photosynthesis at 20–30 °C and a light saturation of CO₂ gas exchange at 350 μmol photons m⁻² s⁻¹.     

Application of the hydro(solvo)thermal technique to the synthesis of metal carbonyl chalcogenide clusters Part 3. Synthesis, structural characterization, and spectroscopic studies of the clusters [{M(CO)4}n(MS4)] (M = Mo, W; N=1, 2)

The methanothermal reactions of M(CO)₆ (M = Mo, W) with Na₂S₂ gave a series of homonuclear clusters [{M(CO)₄}_n(MS₄)]²⁻ (M=Mo, W; N=1, 2), i.e. (Ph₄P)₂[(CO)₄Mo(MoS₄)] (I), (Ph₄P)₂[(CO)₄W(WS₄)] (II), (Ph₄P)₂[(CO)₄Mo(MoS₄)Mo(CO)₄] (III) and (Ph₄P)₂[(CO)₄W(WS₄)W(CO)₄] (IV). The two dimers, I and II, as well as the two trimers, III and IV, are isostructural to each other, respectively. All compounds crystallize in the triclinic space group with Z=2. The cell dimensions are: a=12.393(8), b=19.303(9), c=11.909(6) Å, =102.39(5), β=111.54(5), γ=73.61(5)°, V=2522(3) ų at T=23 °C for I; a=12.390(3), b=19.314(4), c=11.866(2) Å, =102.66(2), β=111.49(1), γ=73.40(2)°, V=2511(1) ų at T=23 °C for II; a=11.416(3), b=22.524(4), c=10.815(4) Å, =91.03(2), β=100.57(3), γ=88.96(2)°, V=2733(1) ų at T=−100 °C for III, a=11.498(1), b=22.600(4), c=10.864(3) Å, =90.92(2), β=100.85(1), γ=88.58(1)°, V=2771(2) ų at T=23 °C for IV. The dimers are each formed by the coordination of the tetrathiometalate as a bidentate chelating ligand to an M(CO)₄ fragment while addition of another M(CO)₄ fragment to the dimers results in the trimers. All compounds contain both tetrahedral and octahedral metal centers with the formal 6+ and 0 oxidation states, respectively.     

Effects of temperature, irradiance, and daylength on the marine diatom Leptocylindrus danicus Cleve. IV. Growth

Growth and dark respiration rates of the marine diatom Leptocylindrus danicus Cleve were measured in axenic batch culture under 49 combinations of temperature (5, 10, 15, 20°C), daylength(15:9, 12:12, 9:15 LD), and irradiance (at least four irradiances per daylength). Cell division rates exhibited a temperature-dependent daylength effect. Optimal temperatures occurred between 15 and 20°C. Both the initial slope () and the growth rate at light saturation (μ_max) were strongly influenced by temperature; increased five-fold and μ_max by an order of magnitude between 5 and 20°C. The compensation irradiance (I_c) was independent of temperature. μ_max was 2.7 div day⁻¹ at 20°C, 2.6 at 15°C, 1.1 at 10°C, and 0.3 at 5 °C. Cells grown under 15:9 and 12:12 LD exhibited similar growth-light curves at 20°C and at 15°C. μ_max of cells grown under 9:15 LD at these temperatures were substantially lower than μ_max under longer daylengths. Growth at 10 and 5°C was independent of daylength.

Dark respiration rates were a linear function of cell division rates at 10, 15, and 20°C, and support the concept that growth rate is dependent on dark respiration rate. These relationships were not influenced by daylength. A detectable relationship between dark respiration and growth at 5°C was not observed.

Photosynthesis and excretion showed temperature-dependent curvilinear relationships with growth rate, reflecting the lower saturation irradiance for growth compared to light saturation of photosynthesis and excretion. The relationship between Chl a-specific photosynthesis and growth was controlled by the C:Chl a ratio, which showed a positive correlation with cell division rate. At 15 and 20°C, light saturation of growth was associated with C:Chl a ratios of 40 to 60; at 5 and 10°C, cells growing at μ_max contained C:Chl a in ratios of 80 to 110.     

Shifts in thermoregulatory patterns with pregnancy in the poikilothermic mammal—The naked mole-rat (Heterocephalus glaber)

1. 1. The naked mole-rat (Heterocephalus glaber) is a poikilothermic mammal. During gestation metabolic shifts that differ from both mammalian and reptilian thermoregulatory patterns occurred.

2. 2. Body temperature was directly dependent on ambient temperature. At low ambient temperatures the temperature differential (T_b − T_a) was approximately 3°C, whereas at higher ambient temperatures the temperature differential diminished.

3. 3. In early pregnancy (prior to week 3) oxygen consumption at low ambient temperatures was greater than that of non-reproductive animals. A maximal metabolic rate (3.2 ± 1.0 ml O₂ . g⁻¹ . h⁻¹) occurred at an ambient temperature of 27°C. Thereafter the endothermic pattern of metabolism with increasing ambient temperatures was evident. Oxygen consumption decreased with increasing ambient temperature to minimal rates of 1.2 ± 0.1 ml O₂ . g⁻¹ . h⁻¹ over the ambient temperature range of 31–34°C.

4. 4. Oxygen consumption in late pregnancy (1.8 ± 0.1 ml O₂ . g⁻¹ . h⁻¹) was not correlated with ambient temperature over the entire ambient temperature range measured (24–36°C).

5. 5. Differences in thermoregulation in early and late pregnancy may be attributed to different rates of heat loss as a consequence of (a) changes in surface area and body mass or (b) vascular changes. Furthermore the thermoregulatory changes in late pregnancy may indicate that maximal overall metabolic capacity had been reached, for peak resting metabolism (expressed per animal rather than per gram body mass) in early pregnancy was similar to observed metabolism in late pregnancy.

6. 6. The dissociation of metabolism from both ambient temperature and body temperature in late pregnancy could confer an energetic advantage to this arid dwelling underground inhabitant; for it may enable the breeding female to partition a greater portion of available energy into reproduction.

In vitro excystment of the metacercaria of Plagiorchis species 1 (Trematoda, Plagiorchiidae)

1986. In vitro excystrnent of the metacercaria of Plagiorchis species 1 (Trematoda, Plagiorchiidae). International Journal for Parasitology 16: 641–645. An optimal hatching success of Plagiorchis species 1 metacercariae (100% excystment, active metacercariae, mean hatching speed 2–10 min, lowest variance of the mean speed) was observed after pretreatment in an HCl-pepsin solution at pH 2.0 and 42°C for 60–70 min, and incubation in a hatching medium at 42 °C and pH 7.3–8.0 with a bile salt (Nacholate), NaHCO₃, and a reductant (cysteine with 100% N₂). The minimum conditions for nearly 100% excystment with lower hatching speeds and higher variances were the presence of NaHCO₃, an oxygen concentration reduced to about 3% in the gas phase, pH> 7.3 and a temperature near 30°C if Na-cholate was absent, or in the presence of the bile salt, a phosphate buffer at pH> 5.0 and room temperature only. Obviously some hatching factors acted interchangeably with compensation for missing stimuli by others. The effect of the bile salt was comparable with that of other surfactants. The metacercariae excysted in nonenzymatic media, which implies an active hatching mechanism.     

Freezing resistance improvement of Lactobacillus reuteri by using cell immobilization

Lactobacillus reuteri shows certain beneficial effects to human health and is recognized as a probiotic. However, its application in frozen foods is still not popular because of its low survival during freezing and frozen storage. Cell immobilization technique could effectively exert protection effects to microbial cells in order to enhance their endurance to unfavorable environmental conditions as well as to improve their viability and cell concentration. Ca-alginate and κ-carrageenan were used to immobilize L. reuteri in this research, and the immobilized cells were exposed to different freezing temperatures, i.e. − 20 °C, − 40 °C, − 60 °C, − 80 °C, and stored at − 40 °C and − 80 °C for 12 weeks. The objectives were to study the protection effects of cell immobilization against the adverse conditions of freezing and frozen storage, and the effects of freezing temperatures to the immobilized cells. Cell immobilization was used to raise the survival of L. reuteri during freezing and frozen storage in order to develop frozen foods with the probiotic effects of L. reuteri. Results indicated that immobilized L. reuteri possessed better survival in both freezing and frozen storage. The survival of immobilized L. reuteri was higher than that of free cells, and the effects of lower freezing temperature were better than higher freezing temperature. The immobilization effects of Ca-alginate were found to be superior to κ-carrageenan. Cell immobilized L. reuteri exhibits potential to be used in frozen foods.     

Ultraviolet-B irradiation-induced freezing tolerance in relation to antioxidant system in winter wheat (Triticum aestivum L.) leaves

Seven-day-old seedlings of winter wheat (Triticum aestivum L.) in a growth chamber were exposed to ultraviolet-B (UV-B) irradiation for 20 days with daily biologically effective (BE) UV-B irradiation (UV-B_BE) at low (4.2 kJ m⁻² day⁻¹, L_UVB) and high (7.0 kJ m⁻² day⁻¹, H_UVB) levels. The UV-B irradiated seedlings and the control without UV-B irradiation were then subjected to freezing stress at −6 °C for 6 h and recovered to 20 °C with gradually increased temperature, to investigate the effects of UV-B irradiation on freezing tolerance. During the UV-B exposure, both L_UVB and H_UVB irradiated seedlings had lower half lethal temperature (LT₅₀) values in comparison with the control, and L_UVB more effectively decreased the LT₅₀ values than H_UVB. Moreover, foliar concentrations of thiobarbituric acid reactive substances (TBARS) in the UV-B irradiated seedlings were lower than that of control after recovery from freezing stress. Hydrogen peroxide (H₂O₂) rapidly increased after UV-B exposure, as did activity of superoxide dismutase (SOD). After recovery from freezing stress, activities of catalase (CAT), guaiacol peroxidase (GPX) and glutathione reductase (GR) increased in both L_UVB and H_UVB leaves, whereas activities of ascorbate peroxidase (APX) and monodehydroascorbate reductase (MDHAR) significantly increased only in the L_UVB leaves. Furthermore, the ascorbic acid (AsA) concentration and reduced-to-oxidized ascorbate ratio (AsA/DHA) increased in the L_UVB leaves both at the end of UV-B exposure and after recovery from freezing stress. However, the reduced glutathione (GSH) concentration, together with reduced-to-oxidized glutathione ratio (GSH/GSSG) increased in both L_UVB and H_UVB leaves after recovery from freezing stress. UV-B irradiation increased freezing tolerance in winter wheat seedlings, and this response appears to involve the scavenging enzymes and compounds in the antioxidant defense systems, particularly the ascorbate–glutathione cycle.     

Kinetics and mechanism of the stoichiometric oxygenation of [Cu(fla)(idpa)]ClO4 [fla=flavonolate, IDPA=3,3′-imino-bis(N,N-dimethylpropylamine)] and the [Cu(fla)(idpa)]ClO4-catalysed oxygenation of flavonol

Oxygenation of [Cu^II(fla)(idpa)]ClO₄ (fla=flavonolate; IDPA=3,3′-iminobis(N,N-dimethylpropylamine)) in dimethylformamide gives [Cu^II(idpa)(O-bs)]ClO₄ (O-bs=O-benzoylsalicylate) and CO. The oxygenolysis of [Cu^II(fla)(idpa)]ClO₄ in DMF was followed by electronic spectroscopy and the rate law −d[{Cu^II(fla)(idpa)}ClO₄]/dt=k_obs[{Cu^II(fla)(idpa)}ClO₄][O₂] was obtained. The rate constant, activation enthalpy and entropy at 373 K are k_obs=6.13±0.16×10⁻³ M⁻¹ s⁻¹, ΔH^‡=64±5 kJ mol⁻¹, ΔS^‡=−120±13 J mol⁻¹ K⁻¹, respectively. The reaction fits a Hammett linear free energy relationship and a higher electron density on copper gives faster oxygenation rates. The complex [Cu^II(fla)(idpa)]ClO₄ has also been found to be a selective catalyst for the oxygenation of flavonol to the corresponding O-benzoylsalicylic acid and CO. The kinetics of the oxygenolysis in DMF was followed by electronic spectroscopy and the following rate law was obtained: −d[flaH]/dt=k_obs[{Cu^II(fla)(idpa)}ClO₄][O₂]. The rate constant, activation enthalpy and entropy at 403 K are k_obs=4.22±0.15×10⁻² M⁻¹ s⁻¹, ΔH^‡=71±6 kJ mol⁻¹, ΔS^‡=−97±15 J mol⁻¹ K⁻¹, respectively.     

Synthesis and characterization of SrCu2(O2CR)3(bdmap)3 and Bi2(O2CCH3)4(bdmap)2(H2O) (R = CH3, CF3; bdmap = 1,3-bis(dimethylamino)-2-propanolato)

New mixed metal complexes SrCu₂(O₂CR)₃(bdmap)₃ (R = CF₃ (1a), CH₃ (1b)) and a new dinuclear bismuth complex Bi₂(O₂CCH₃)₄(bdmap)₂(H₂O) (2) have been synthesized. Their crystal structures have been determined by single-crystal X-ray diffraction analyses. Thermal decomposition behaviors of these complexes have been examined by TGA and X-ray powder diffraction analyses. While compound 1a decomposes to SrF₂ and CuO at about 380°C, compound 1b decomposes to the corresponding oxides above 800°C. Compound 2 decomposes cleanly to Bi₂O₃ at 330°C. The magnetism of 1a was examined by the measurement of susceptibility from 5–300 K. Theoretical fitting for the susceptibility data revealed that 1a is an antiferromagnetically coupled system with g = 2.012(7), −2J = 34.0(8) cm⁻¹. Crystal data for 1a: C₂₇H₅₁N₆O₉F₉Cu₂Sr/THF, monoclinic space group P2₁/m, A = 10.708(6), B = 15.20(1), C = 15.404(7) Å, β = 107.94(4)°, V = 2386(2) ų, Z = 2; for 1b: C₂₇H₆₀N₆O₉Cu₂Sr/THF, orthorhombic space group Pbcn, A = 19.164(9), B = 26.829(8), C = 17.240(9) Å, V = 8864(5) ų, Z = 8; for 2: C₂₂H₄₈O₁₁N₄Bi₂, monoclinic space group P2₁/c, A = 17.614(9), B = 10.741(3), C = 18.910(7) Å, β = 109.99(3)°, V = 3362(2) ų, Z = 4.     

Heterobimetallic aggregates of copper(I) with thiotungstates and thiomolybdates. Synthesis and characterization of polymeric (NEt4)3[Cu4(NCS)5WS4], (NEt4)2[(CuNCS)3WS4] and (NEt4)2[(CuNCS)4WS4], M = Mo, W

Reaction of (NEt₄)₂MS₄ (M = Mo, W) with CuCl and KSCN (or NH₄SCN) in acetone or acetonitrile affords a new set of mixed metal–sulfur compounds: infinite anionic chains Cu₄(NCS)₅MS_4³⁻ (1,2), (CuNCS)₃WS_4²⁻ (3) and two dimensional polymeric dianions (CuNCS)₄MS_4²⁻ (4,5). Crystal of 1 (M = W) and 3 are triclinic, space group P1(1:a = 10.356(2),b = 15.039(1),c = 17.356(2)Å, = 78.27(1)°, β = 88.89(2)° and γ = 88.60(1)°,Z = 2,R = 0.04 for 3915 independent data;3:a = 8.449(2),b = 14.622(4),c = 15.809(8)Å, = 61.84(3)°, β = 73.67(3)° and γ = 78.23(2)°,Z = 2,R = 0.029 for 6585 independent data). Crystals of 4 (M = W) and 5 (M = Mo) are monoclinic, space group P2₁/m,Z = 2 (4:a = 12.296(4),b = 14.794(4),c = 10.260(3)Åand β = 101.88(3)°,R = 0.034 for 4450 independent data;5:a = 12.306(2),b = 14.809(3),c = 10.257(2)Åand β = 101.99(3)°,R = 0.043 for 3078 independent data). The crystal structure determinations of 4 and 5 show that four edges of the tetrahedral MS_4²⁻ core are coordinated by copper atoms forming WS₄Cu₄ aggregates linked by eight-membered Cu(NCS)₂Cu rings. A two-dimensional network is thus formed in the diagonal (101) plane. The space between the anionic two-dimensional networks is filled with the NEt_4⁺ cations. Additional NCS groups lead to the [Cu₄(NCS)₅WS₄]³⁻ (1) trianion connected by NCS bridges forming pseudo-dimers. These latter are held together by weak CuS(NCS) interactions giving rise to infinite chains along a direction parallel to [100]. In contrast complex3 develops infinite chains from WS₄Cu₃ aggregates with the same Cu(NCS)₂Cu bridges as in 4 and 5. These chains are running along a direction parallel to [010]. The structural data of the different types of polymeric compounds containing MS_4²⁻ and CuNCS have been used to interpret vibrational spectroscopic data of the thiocyanate groups.     

Mitochondrial respiratory chain of Tetrahymena pyriformis The properties of submitochondrial particles and the soluble b and c type pigments

Submitochondrial particles isolated from Tetrahymena pyriformis contain essentially the same redox carriers as those present in parental mitochondria: at pH 7.2 and 22 °C there are two b-type pigments with half-reduction potentials of −0.04 and −0.17 V, a c-type cytochrome with a half reduction potential of 0.215 V, and a two-component cytochrome a₂ with E_m7.2 of 0.245 and 0.345 V.

EPR spectra of the aerobic submitochondrial particles in the absence of substrate show the presence of low spin ferric hemes with g values at 3.4 and 3.0, a high spin ferric heme with g = 6, and a g = 2.0 signal characteristic of oxidized copper. In the reduced submitochondrial particles signals of various iron-sulfur centers are observed.

Cytochrome c₅₅₃ is lost from mitochondria during preparation of the submitochondrial particles. The partially purified cytochrome c₅₅₃ is a negatively charged protein at neutral pH with an E_m7.2 of 0.25 V which binds to the cytochrome c-depleted Tetrahymena mitochondria in the amount of 0.5 nmol/mg protein with a K_D of 0.8 · 10⁻⁶ M. Reduced cytochrome c₅₅₃ serves as an efficient substrate in the reaction with its own oxidase. The EPR spectrum of the partially purified cytochrome c₅₅₃ shows the presence of a low spin ferric heme with the dominant resonance signal at g = 3.28.

A pigment with an absorption maximum at 560 nm can be solubilized from the Tetrahymena cells with butanol. This pigments has a molecular weight of approx. 18 000, and E_m7.2 of −0.17 V and exhibits a high spin ferric heme signal at g = 6.     

The influence of temperature on respiration of diapausing pupae of Pieris brassicae (Lepidoptera)

The respiration of diapausing Pieris pupae has been measured at different temperatures between 5 and 35°C in animals maintained at 20°C, either 14 or 74 days after larvo-pupal ecdysis or at 5°C for 30 or 60 days.

The sudden transfer of animals from 5 to 15, 20, 25, 30, 35°C or from 20 to 30, 35°C results in a respiratory overshoot whose characteristics (duration, height, extra-respiration) depend on experimental conditions.

After a certain period of acclimation, overshoots are eliminated. The respiratory rate except for animals maintained during 74 days at 20°C can then be represented as an exponential function of temperature.

The Q₁₀ values change according to the treatment given to pupae.

The respiratory rate of male pupae is higher than that of female ones.

The following points are discussed:

1. 1.|The meaning of overshoots is analysed according to economy and metabolic homeostasis, showing the existence of acclimation.

2. 2.|Exponential curves which are not relevant to non-diapausing pupae or to the diapausing ones taken at larvo-pupal molting are characteristic of steady metabolism. These curves can be interpreted as the result of the temperature effect on a master respiratory reaction which would then be rate limiting.

3. 3.|Wintering leads to gradual and slow adaptation to cold temperatures which brings both a respiratory increase, a decrease of the Q₁₀ and of the activation energy of the master reaction.

Temperature and growth in Carcinus maenas L. (Decapoda: Portunidae) larvae reared in the laboratory from hatching through metamorphosis

Larvae of Carcinus maenas L. were reared in the laboratory from hatching through metamorphosis at 9, 12, and 18°C. Dry weight (DW) and elemental contents of carbon (C), nitrogen (N), and hydrogen (H) were analysed at short intervals through successive larval moulting cycles (four zoea-stages, megalopa), and newly metamorphosed crabs. C. maenas larvae grew significantly during all instars, at all temperatures tested. Biomass (DW, C, N, H) and energy (Joule) slightly declined shortly before ecdysis in zoea stages. This terminal decrease was more distinct in the megalopa stage, where ≈39 and 83% of the maximum energy attained, was lost at 12 and 18°C, respectively. Changes of biomass and energy in successive moult cycles showed best fits to quadratic equations, whereas their maximum in successive larval instars formed exponential sequences with time. Due to parabolic growth curves, biomass and energy accumulation within single instars were discussed as maximum (MG) and effective growth (EG), considering gain both at times of maximum biomass, and shortly before ecdysis. Metamorphosing larvae achieved EG with 1137% (DW), 1195% (C), 1108% (N), 1395% (H), 1339% (Joule) at 12°C, and 1140% (DW), 1099% (C), 1133% (N), 1225% (H), 1107% (Joule) at 18°C, relative to newly hatched zoea-1. Ash content and inorganic C in newly hatched zoea-1, were 29.4% and 5.5% ash, respectively. The stoichiometric C H N method of Gnaiger & Bitterlich was used to assess protein, lipid, and carbohydrate compositions. Obviously proteins formed the major part of larval biomass (>50% DW). C: N ratios indicate that more lipid than protein was built up shortly after moulting, but relatively more protein was subsequently accumulated. Temperature effects on larval growth (MG, EG), growth rates (GR), and gross growth efficiencies (K₁) were discussed. C. maenas zoea stages accumulated energy and biomass with higher efficiencies at 18 than at 12°C. Megalopa growth seemed to be limited at 18°C, showing lower K₁ values than at 12°C. N was accumulated with higher efficiencies than C in all larval stages. Characteristic variations in larval K₁ values between premoult and ecdysis were discussed. Cumulative gross growth efficiencies (MG-related) were calculated as ≈11 and 10%, at 12 and 18°C, respectively.