Karyological study of four Japanese Myotis bats (Chiroptera,Mammalia)

Karyological investigations of four Japanese Myotis species were made based on Gand C-banding pattern analysis. It was revealed that the four species, M. nattereri, M. hosonoi, M. frater kaguyae and M. macrodactylus have all 2n=44 and their karyotypes are, excepting one chromosome pair, identical each other. The only difference in their karyotypes was found on the morphology of the chromosome no. 5. A minute acrocentric (A) was observed in M. nattereri, and a polymorphic (A) and an (M^h) which is a minute metacentric with totally heterochromatic arm was found in M. hosonoi. In M. f. kaguyae, pair no. 5 was a small submetacentric with a totally heterochromatic long arm (SM^h). Polymorphic (SM^h) and (M) which is a small metacentric derived from (SM^h) by a pericentric inversion was seen in M. macrodactylus. Such morphological differentiations of no. 5 were interpreted by assuming an increase of constitutive heterochromatin and also an inversion. The evolutionary pathway in the genus Myotis is assumed to be as follows: (A)(M^h)(SM^h)(M). This assumption was supported by the geographical evidence that the species with the (A) type no. 5 pair is widely distributed in the whole world but the others are restricted to Asia (M^h type) or only to Japan (SM^h and M types).     

Miocene divergence,phenotypically cryptic lineages,and contrasting distribution patterns in common lichen‐forming fungi (Ascomycota: Parmeliaceae)

Despite the recent advancements in recognizing diversity in lichen‐forming fungi, assessing the timing of diversification remains largely unexplored in these important fungal symbionts. To better understand the evolutionary processes driving diversification in common lichen‐forming fungi, we investigated the phylogeny and biogeography of the broadly distributed Melanelixia fuliginosa/M. glabratula group, using molecular data from six nuclear markers. Phylogenetic analyses of individual gene alignments and combined data provide strong evidence for five species‐level lineages within this species complex. Three of these lineages correspond to the previously described species M. fuliginosa, M. glabratula, and M. subaurifera. The remaining two lineages, ‘M. sp. 1’ and ‘M. sp. 2’, merit species recognition based on genealogical concordance. Both M. glabratula and M. subaurifera had broad intercontinental distributions, sharing identical haplotypes among intercontinental populations. Based on the current sampling, M. fuliginosa s.s. was represented exclusively by European material and was not collected in North America. ‘M. sp. 1’ was represented by collections from Scotland and Spain; and ‘M. sp. 2’ was represented by collections in California, USA. Environmental factors driving the contrasting distribution patterns in this group remain unknown. Divergence times estimated using a coalescence‐based multilocus species‐tree approach suggest that diversification within the M. fuliginosa/M. glabratula group occurred exclusively during the Miocene. The results of the present study indicate that phenotypically cryptic lichen‐forming fungal species‐level lineages may be relatively ancient and do not necessarily reflect recent divergence events. Furthermore, diagnosable phenotypic differences may be absent even millions of years after the initial divergence. © 2012 The Linnean Society of London, Biological Journal of the Linnean Society, 2012, ●●, ●●–●●.     

GABA Induces Functionally Active Low-Affinity GABA Receptors on Cultured Cerebellar Granule Cells

The effect of γ-aminobutyric acid (GABA) and its agonists muscimol and 4,5,6,7-tetrahydroisoxazolo[5-4-c]pyridin-3-ol (THIP) on the development of GABA receptors on cerebellar granule cells was studied by cultivation of the cells in media containing these substances. It was found that the presence of 50 μM GABA in the culture media led to the induction of low-affinity GABA receptors (K_D 546 ± 117 nM) in addition to the high-affinity receptors (K_D 7 ± 0.5 nM) which were present regardless of the presence of GABA in the culture media. The functional activity of the GABA receptors was tested by investigating the ability of GABA to modulate evoked glutamate release from the cells. It was found that GABA could inhibit evoked glutamate release (ED₅₀ 10 ± 3 (μM) only when the cells had been cultured in the presence of 50 νM GABA, 50 μM muscimol, or 150 μM THIP, i.e., under conditions where low-affinity GABA receptors were present on the cells. This inhibitory effect of GABA could be blocked by 120 μM bicuculline and mimicked by 50 μM muscimol or 150 μM THIP whereas 150 μM (-)-baclofen had no effect. It is concluded that GABA acting extracellularly induces formation of low-affinity receptors on cerebellar granule cells and that these receptors are necessary for mediating an inhibitory effect of GABA on evoked glutamate release. The pharmacological properties of these GABA receptors indicate that they belong to the so-called GABA_A receptors.     

Repellent activity of Cymbopogon citratus and Tagetes minuta and their specific volatiles against Megalurothrips sjostedti

Cowpea is an important source of protein for people in Africa. However, the crop suffers major damage and yield losses due to bean flower thrips, Megalurothrips sjostedti Trybom (Thysanoptera: Thripidae). Although companion plants are known to reduce the damage caused by insect pests, the role of their volatiles in repelling pests from target plants has been the subject of few investigations. Here, we used the Y‐tube olfactometer experiments and chemical analyses to investigate the effect of volatiles from cowpea flowers and two companion plants; lemongrass, Cymbopogon citratus and Mexican marigold, Tagetes minuta on the olfactory responses of M. sjostedti. The results revealed that M. sjostedti males and females were repelled by the volatiles from freshly cut leaves of C. citratus. The combination of freshly cut leaves of C. citratus and cowpea flower was repellent to females but not to males. The female thrips, but not males, were repelled by the volatiles from the vegetative stage of T. minuta. Fifty‐four compounds were identified in the volatiles from two herbal plants. Among the major compounds, citral and a 4‐component blend comprised of dihydrotagetone, (Z)‐3‐hexenyl acetate, limonene and (Z)‐β‐ocimene repelled females but dihydrotagetone alone attracted females. While myrcene combined with cowpea flower volatiles enhanced the attraction of females M. sjostedti, when tested alone was not attractive. These results highlight the potential of volatiles from C. citratus and T. minuta to repel M. sjostedti females. The use of these plants as companion plants in a cowpea cropping system could reduce M. sjostedti infestation.     

ATPase activity in plasmalemma-rich vesicles isolated by aqueous two-phase partitioning from Vicia faba mesophyll and epidermis: Characterization and influence of abscisic acid and fusicoccin

Plasmalemma-rich microsomal vesicles were prepared from whole leaf and acid-washed epidermal tissue of Vicia faba L. cv. Osnabrücker Markt by aqueous two-phase partitioning in dextran T-500 and polyethylenglycol 1350 aqueous phases. These vesicles were tightly sealed and predominantly right-side out, and contained a K⁺ -stimulated, mg²⁺-dependent and vanadate-sensitive ATPase. The enzyme from both tissues exhibited nearly identical properties: pH optimum 6.4, K_m for ATP 0.60 mM(whole leaf) and 0.67 mM (epidermis). V_max -480 nmol (mg protein)¹ min¹ (whole leaf) and 510 nmol (mg protein)¹ min¹ (epidermis), I₅₀ (Na₃,VO₄) 7.5 μM (whole leaf) and 15 μM (epidermis). The enzyme was not inhibited by NO₃(50 mM)or sodium azide (I mM). DCCD (20 μM) reduced enzyme activity to 50% (whole leaf) and 58% (epidermis), gramicidin S (20 μM) to 36% (whole leaf) and 41%(epidermis). Ca²⁺ inhibited the ATPase [I₅₀, C²⁺: 0.5 mM(whole leaf) and 0.8 mM(epidermis)]. Ca²⁺ inhibited the ATPase [I₅₀, C²⁺ 0.5 mM(whole leaf) und 0.8 (epidermis)]. The vanadate-sensitive ATPase from whole leaf and epidermal tissue was slightly but significantly stimulated by fusicoccin (FC) at a concentration (0.13 μM) promoting stomatal opening. The stimulation was not seen in the solubilized ATPase. Stomata of the cultivar used here were insensitive lo (±)ABA up to 2 μM level which is effective in most other cultivars and species. Likewise, at this concentration no effect of ABA on the activity of the epidermal ATPase was observed. The data are discussed with respect to the interaction of FC and ABA with the ATPase.     

The time sequence of the relation between mean crowding and mean density with some population processes

Summary The theories of the stochastic processes are applied to construct mathematical models for describing the processes of population change as an ever changing the distribution of individuals in a space. These models consist of two mathematical expressions which are named the spatial distribution probability function (Q _n (t)) and the transition probability function (P _i,n (t)), respectively. The former gives the spatial distribution at any future time. Given an actual spatial distribution at any time, the latter function converts it to the spatial distribution at any future time. According to these models, we discussed the time sequence of the mean crowding-mean density relation (Iwao andKuno, 1971) in some population processes such as mortality, birth, immigration, growth, and their combined processes.     

Cyclosporin A Rescues Thymocytes from Apoptosis Induced by Very Low Concentrations of Thapsigargin: Effects on Mitochondrial Function

Raising intracellular calcium levels can induce apoptosis or programmed cell death in many cells. While early rises in intracellular calcium are not universally associated with apoptotic cell death, calcium clearly plays a key role in many of the biochemical events which occur during apoptosis. In this paper we have determined intracellular calcium rises induced by 2, 10, and 100 nMthapsigargin in mouse thymocytes. These concentrations cause increases in cytosolic calcium of 100–250, 400–600, and >1000 nM,respectively. These rises are sustained for at least 85 min and the ratio between the maximum rise caused by 10 nMcompared to 2 nMthapsigargin is 2.1 ± 0.4 (n= 6). Both 2 and 10 nMthapsigargin cause apoptosis at 24 h as shown by DNA fragmentation and morphology when examined by electron microscopy. Cyclosporin A (CsA) inhibits apoptosis caused by 2 nMthapsigargin but not that caused by 10 nMthapsigargin. Electron microscopy of thymocytes treated with 2 nMthapsigargin at 24 h shows intact mitochondria although with altered morphology. There is no loss of ATP or decrease in the ATP/ADP ratio in these cells over 12 h. Mitochondria in cells treated with 10 nMthapsigargin, however, are swollen by 6 h and many are lost by 24 h. These cells show greatly diminished ATP content by 12 h and a decrease in ATP/ADP ratio. Examination of the effects of PMA, an activator of the plasma membrane calcium ATPase pump, on cells treated with 10 nMthapsigargin suggests that two pools of calcium may be responsible for the differential effects of the two calcium levels in the cells. Probing of the mitochondrial membrane potential (MMP) by rhodamine 123 staining of live cells shows that the collapse of the MMP caused by 10 nMthapsigargin is unaffected by CsA. The MMP is also reduced in cells treated with 2 nMthapsigargin but this is restored by CsA. Cells are also rescued from apoptosis caused by 2 nMthapsigargin by incubation with FK506. This immunosuppressive agent has no effect on the membrane permeability transition induced in isolated mitochondria. These results suggest that very low rises in intracellular calcium in thymocytes cause activation-induced cell death inhibited by CsA and FK506 and are without effect on ATP levels and therefore do not involve irreversible mitochondrial damage. Exceeding these calcium levels by only twofold results in apoptosis accompanied by reduced ATP levels and mitochondrial damage, although apoptotic cell death in this instance is unaffected by the classic inhibitor of mitochondrial permeability transition, CsA.     

The root–soil system of Norway spruce subjected to turning moment: resistance as a function of rotation

The reactions of trees to wind, rockfall, and snow and debris flow depend largely on how strong and deformable their anchorage in the soil is. Here, the resistive turning moment M of the root–soil system as a function of the rotation ϕ at the stem base plays the major role. M(ϕ) describes the behavior of the root–soil system when subject to rotational moment, with the maximum M(ϕ) indicating the anchorage strength M _a of the tree. We assessed M(ϕ) of 66 Norway spruce (Picea abies L. Karst) by pulling them over with a winch. These 45- to 170-year-old trees grew at sites of low and high elevation, with a diameter at breast height DBH = 14–69 cm and a height H = 9–42 m. M(ϕ) displayed a strong nonlinear behavior. M _a was reached at a lower ϕ for large trees than for small trees. Thus overhanging tree weight contributed less to M _a for the large trees. Overturning also occurred at a lower ϕ for the large trees. These observations show that the rotational ductility of the root–soil system is higher for small trees. M _a could be described by four monovariate linear regression equations of tree weight, stem weight, stem volume and DBH ² ·H (0.80 < R ² < 0.95), and ϕ at M _a, ϕ _a, by a power law of DBH²·H (R ² = 0.85). We found significantly higher M _a for the low-elevation spruces than for the high-elevation spruces, which were more shallowly anchored, but no significant difference in ϕ _a. The 66 curves of M(ϕ), normalized (_n) by M _a in M-direction and by ϕ _a in ϕ-direction, yielded one characteristic average curve: . Using and the predictions of M _a and ϕ _a, it is shown that M(ϕ) and the curves associated with M(ϕ) can be predicted with a relative standard error ≤25%. The parameterization of M(ϕ) by tree size and weight is novel and provides useful information for predicting with finite-element computer models how trees will react to natural hazards.     

The association of proctolin with a ventral abdominal muscle of Locusta migratoria

The association of proctolin with the external ventral protractor muscle of the VIIth abdominal segment (M234) of Locusta migratoria was investigated using immunohistochemistry and RP-HPLC in conjunction with the sensitive locust oviduct bioassay. Immunohistochemistry of whole-mount tissues revealed two proctolin-like immunoreactive axons in N2B_2b1 (the nerve branch which innervates M234) as well as immunoreactive processes and varicosities on the surface of M234. Immunogold staining of M234 demonstrated that the proctolin-like immunoreactivity was present in electron-dense granules in its motor terminals. A material indistinguishable from proctolin and with proctolin-like bioactivity co-eluted with authentic proctolin on two different RP-HPLC systems. Bath application of proctolin at concentrations greater than 10^-11 M resulted in a dose-dependent increase in the neurally-evoked fast twitch amplitude and duration of M234. Concentrations greater than 10^-9 M resulted in a dose-dependent increase in basal tonus of M234. These results indicate that proctolin, or a peptide very similar to proctolin, is present in the motor innervation of M234 and acts as a cotransmitter and/or neuromodulator at this typical fast skeletal muscle.Abbreviations M234 external ventral protractor muscle of the Vllth abdominal segment - RP-HPLC reverse-phase high pressure liquid chromatography - TFA trifluoroacetic acid     

AnO(N 2 logN) restriction map comparison and search algorithm

We present anO(R logP) time,O(M+P ² ) space algorithm for searching a restriction map withM sites for the best matches to a shorter map withP sites, whereR, the number of matching site pairs, is bounded byMP. As first proposed by Watermanet al. (1984,Nucl. Acids Res. 12, 237–242) the objective function used to score matches is additive in the number of unaligned sites and the discrepancies in the distances between adjacent aligned sites. Our algorithm is basically a sparse dynamic programming computation in which “candidate lists” are used to model the future contribution of all previously computed entries to those yet to be computed. A simple modification to the algorithm computes the distance between two restriction maps withM andN sites, respectively, inO(MN(logM+logN)) time. This author’s work was supported in part by National Library of Medicine Grant R01-LM4960. This author’s work was supported in part by National Library of Medicine Grant R01-LM5110.     

Variation of the parental genome contribution in segregating populations derived from biparental crosses and its relationship with heterosis of their Design III progenies

The variation of the parental genome contribution (PGC) and its relationship with the genetic architecture of heterosis have received little attention. Our objectives were to (1) derive formulas for the variance of PGC in selfing, backcross (BC) or intermated generations produced from biparental crosses of homozygous parents, (2) investigate the correlation r(Z₂ ,\Uppsi_M ) r(Z_{2} ,\Uppsi_{M} ) of the PGC (\Uppsi_M ) (\Uppsi_{M} ) estimated by a set M of markers, with Z ₂ (half the trait difference between each pair of BC progenies) in the Design III, and (3) interpret experimental results on this correlation with regard to the genetic basis of heterosis. Under all mating systems, the variance of PGC is smaller in species with a larger number and more uniform length of chromosomes. It decreases with intermating and backcrossing but increases under selfing. The ratio of variances of PGC in F₁DH (double haploids), F₂ and BC₁ populations is 4:2:1, but it is smaller in advanced selfing generations than expected for quantitative traits. Thus, altering the PGC by marker-assisted selection for the genetic background is more promising (i) in species with a smaller number and/or shorter chromosomes and (ii) in F₂ than in progenies of later selfing generations. The correlation r(Z₂ ,\Uppsi_M ) r(Z_{2} ,\Uppsi_{M} ) depends on the linkage relationships between M and the QTL influencing Z₂ as well as the augmented dominance effects d_i^* d_{i}^{*} of the QTL, which include dominance and additive × additive effects with the genetic background, and sum up to mid-parent heterosis. From estimates of r(Z₂ ,\Uppsi_M ) r(Z_{2} ,\Uppsi_{M} ) as well as QTL studies, we conclude that heterosis for grain yield in maize is caused by the action of numerous QTL distributed across the entire genome with positive d_i^* d_{i}^{*} effects.     

Characterization ofl-leucine transport in the opportunistic yeastsMalassezia furfur andMalassezia pachydermatis

The lipophilic yeastsMalassezia furfur andM. pachydermatis show an initial rapid uptake ofl-leucine followed by slower steady-state rates. At least two independent transport systems forl-leucine were present in both species. The high-affinity system forM. furfur had a K_T of 0.047 µM with a J_max of 222 fM/min/10⁶ cells (65 pM/min/mg dry weight), whereas forM. pachydermatis the K_T was 0.067 µM with a J_max of 709 fM/min/10⁶ cells (89 pM/min/dry weight). The low-affinity system forM. furfur had a K_T of 646 µM with a J_max of 1.62 pM/min/10⁶ cells (0.5 nM/min/mg dry weight) and that ofM. pachydermatis had a K_T of 3.3 µM with a J_max of 9.97 pM/min/10⁶ cells (1.3 nM/min/mg dry weight). Both transport systems were energy-dependent. Cells incubated with Tween 80 showedl-leucine uptake via both transport systems. Cells incubated with a combination of glucose (1%) and Tween 80 (0.01%) showed decreased transport rates for the high-affinity system for both species as compared with cells incubated only with glucose. The low-affinity transport system of both species in the presence of glucose plus Tween 80 showed an initial rapid uptake followed by greater efflux than influx ofl-leucine.l-Leucine demonstrated binding to Tween 80, but the major effect of Tween 80 on membrane transport inMalassezia appears to be on the efflux of transported molecules.     

Structural variations in dinuclear model hydrolases and hydroxamate inhibitor models: synthetic, spectroscopic and structural studies

Reactions of the structural model hydrolases [M₂(OAc)₄(H₂O)(Im)₄]; M=Mn (E^′); M=Co (D^′); M=Ni (B^′) and [M₂(OPiv)₄(H₂O)(tmen)₂]; M=Mn (E″); M=Co (D″); M=Ni (B″) with a number of hydroxamic acids, RHA (aceto- (R=CH₃), benzo- (R = C₆H₅) and N-phenylacetohydroxamic acid (NPhAHA)) gave a series of hydroxamate dibridged complexes [M₂(OAc)(RA)₂(Im)₄][OTf] and [M₂(OPiv)(RA)₂(tmen)₂][OTf]; M=Co, Ni, in which the bridging hydroxamates exhibit a novel bonding mode in which the deprotonated hydroxamate hydroxyl bridges the two metal centres only. The formation of this type of structure by NPhAHA is the first example involving a secondary hydroxamic acid. These complexes are good structural models of the acetohydroxamate-inhibited C³¹⁹A variant of Klebsiella aerogenes urease (KAU) and their structures are close to those previously reported for complexes containing tmen capping ligands. Reaction with glutarodihydroxamic acid leads to hydroxylamine elimination and formation of a dimer containing deprotonated N-hydroxyglutarimide as bridging ligand but in this case the structure contains pentacoordinated Co(II) and only one bridging acetate in contrast to the tmen-based series where the analogous complex contains hexacoordinated Co(II) and two bridging acetates. Reaction of [Mn₂(OAc)₂(μ-OAc)₂(μ-H₂O)(tmen)₂] with acetohydroxamic acid (AHA) gave the first structurally characterized manganese hydroxamate, [Mn₂(OAc)₃(AA)(tmen)₂] with the same bridging/chelating mode of hydroxamate bonding as in the analogous cobalt and nickel complexes, although only one bridging hydroxamate occurs in the manganese complex in contrast to the two bridging hydroxamates in the cobalt and nickel complexes. The isolation of the dimanganese hydroxamate bridged complex suggests that hydroxamic acids may also inhibit the dimanganese based metallohydrolase, arginase.     

Cumulative Damage Survival Models for the Randomized Complete Block Design

A continuous time discrete state cumulative damage process {X(t), t ≥ 0} is considered, based on a non‐homogeneous Poisson hit‐count process and discrete distribution of damage per hit, which can be negative binomial, Neyman type A, Polya‐Aeppli or Lagrangian Poisson. Intensity functions considered for the Poisson process comprise a flexible three‐parameter family. The survival function is S(t) = P(X(t) ≤ L) where L is fixed. Individual variation is accounted for within the construction for the initial damage distribution {P(X(0) = x) | x = 0, 1, …,}. This distribution has an essential cut‐off before x = L and the distribution of L – X(0) may be considered a tolerance distribution. A multivariate extension appropriate for the randomized complete block design is developed by constructing dependence in the initial damage distributions. Our multivariate model is applied (via maximum likelihood) to litter‐matched tumorigenesis data for rats. The litter effect accounts for 5.9 percent of the variance of the individual effect. Cumulative damage hazard functions are compared to nonparametric hazard functions and to hazard functions obtained from the PVF‐Weibull frailty model. The cumulative damage model has greater dimensionality for interpretation compared to other models, owing principally to the intensity function part of the model.     

Baseline levels in muscle relaxation training

Variations in the baseline levels of physiological measures, a familiar problem in psychophysiological research, can affect the results of clinical applications and research in the self-control of bodily processes. In this presentation, the problem is illustrated within the context of skeletal muscle relaxation training using continuous biofeedback(BF) based on surface electromyographic(EMG) activity. In terms of the Law of Initial Values(LIV), higher EMG levels are expected to be associated with greater decreases during training. The combined results of two studies documented an LIV-like effect for pretraining baseline levels with greater EMG decreases after training for subjects with the higher pretraining baselines. Left uncorrected, such baseline differences were shown to lead to discrepant results between two identical studies, and therefore to conflicting conclusions about the effectiveness of these procedures. The available methods suggested to correct for the biasing effect of baseline differences in research are described, with particular emphasis on the analysis of covariance.This research was supported in part by NIH Grants MH24222 and AI-10398. The authors would like to thank Miss Sharon Robinson for supervising the collection of data and for her constructive comments regarding the training procedures of the studies described.     

Identifying the dominant process (physical versus biological) in pelagic marine ecosystems from field estimates of chlorophyll a and phytoplankton production

A new approach is described to identify the dominant process (physical versus biological) in a pelagic marine ecosystem, from simple biological oceanographic field variables. The approach is based on quantification of the matching (M) between phytoplankton production (P) and losses, from field estimates of chlorophyll a(Chl) and P. Coefficient M is estimated for a wide range of oceanic and coastal environments and of trophic characteristics, using dat from the literature. Results show that M characterizes the dominance of physical versus biological processes in pelagic systems. The coefficient may be especially useful as a means for extracting process information on pelagic marine ecosystems from large data sets of Chl and P, e.g. recorded by moored instruments or provided by satellite images of ocean colour.      

Molecular phylogeny of Macrolycus (Coleoptera: Lycidae) with description of new species from China

Macrolycus is a genus of net‐winged beetles with 69 species distributed in the eastern Palearctic and northernmost part of the Oriental region. The first molecular phylogeny of Macrolycus was produced using an rrnL + tRNA‐Leu + nad1 mtDNA fragment. The major lineages and species limits were identified with morphology and molecular data. We propose that Cerceros is a subgenus of Macrolycus to enable identification of all adult specimens in the genus without DNA sequencing. Two species groups are proposed in Macrolycus s. str. and six in Cerceros. Additionally, twelve Macrolycus species are newly described from China: M. aquilinus, M. baihualingensis, M. bicolor, M. guangxiensis, M. jianfenglingensis, M. kuatunensis, M. lizipingensis, M. parvus, M. phoeniceus, M. rhodoneurus, M. rosaceus and M. sichuanensis. Macrolycus holzschuhi is proposed to be a junior subjective synonym of M. jeanvoinei. The highest diversity of Macrolycus is found in southern China. The species from the main islands of Japan are placed in two species groups: M. excellens is a sister to remaining species of the M. murzini group and the M. flabellatus group is a monophylum of closely related species in a sister position to the M. bicolor group.     

Interactions between Symbiotic Nitrogen Fixation, Combined-N Application, and Photosynthesis in Pisum sativum

The effect of photosynthetic photon flux density (PPFD) on nitrogen utilization was determined in peas (Pisum sativum L. cv. Alaska) inoculated with Rhizobium leguminosarum and treated with nutrient solutions containing no combined nitrogen, 16 mM NO₃^?, or 16 mM NH₄⁺. Plants were grown under controlled conditions at three PPFD values ranging from severely limiting to nearly saturating. Carboxylation efficiencies and CO₂-exchange rates were highest in the N₂-fixing plants and lowest in plants supplied with NH₄⁺, and they generally increased with increasing PPFD. Photoefficiencies increased with PPFD but did not differ appreciably with the form of nitrogen applied. Nitrogen fixation, calculated from C₂H₂-reduction and H₂-evolution data, was inhibited more by NH₄⁺ than by NO₃^?application. Inhibition was counteracted by increasing PPFD. Percentage nitrogen decreased with increasing PPFD in plants treated with combined nitrogen and increased in the plants dependent on N₂ fixation. The data reveal that photosynthetic efficiency and the capacity to fix N₂ in peas are functions of PPFD and the availability of combined nitrogen and that these two factors are interrelated.     

The internal rotenone‐insensitivae NADPH dehydrogenase contributes to malate oxidation by potato tuber and pea leaf mitochondria

Inside-out submitochondrial particles from both potato (Solanum tuberosum L. cv. Bintje) tubers and pea (Pisum sativum L. cv. Oregon) leaves possess three distinct dehydrogenase activities: Complex I catalyzes the rotenone-sensitive oxidation of deamino-NADH, ND_in(NADPH) catalyzes the rotenone-insensitive and Ca²⁺-dependent oxidation of NADPH and ND_in(NADH) catalyzes the rotenone-insensitive and Ca²⁺-independent oxidation of NADH. Diphenylene iodonium (DPI) inhibits complex I, ND_in(NADPH) and ND_in (NADH) activity with a K_i of 3.7, 0.17 and 63 µM, respectively, and the 400-fold difference in K_i between the two ND_in made possible the use of DPI inhibition to estimate ND_in (NADPH) contribution to malate oxidation by intact mitochondria. The oxidation of malate in the presence of rotenone by intact mitochondria from both species was inhibited by 5 µM DPI. The maximum decrease in rate was 10–20 nmol O₂ mg^?1 min^?1. The reduction level of NAD(P) was manipulated by measuring malate oxidation in state 3 at pH 7.2 and 6.8 and in the presence and absence of an oxaloacetate-removing system. The inhibition by DPI was largest under conditions of high NAD(P) reduction. Control experiments showed that 125 µM DPI had no effect on the activities of malate dehydrogenase (with NADH or NADPH) or malic enzyme (with NAD⁺ or NADP⁺) in a matrix extract from either species. Malate dehydrogenase was unable to use NADP⁺ in the forward reaction. DPI at 125 µM did not have any effect on succinate oxidation by intact mitochondria of either species. We conclude that the inhibition caused by DPI in the presence of rotenone in plant mitochondria oxidizing malate is due to inhibition of ND_in(NADPH) oxidizing NADPH. Thus, NADP turnover contributes to malate oxidation by plant mitochondria.     

Die verteilung der Propriorezeptoren im spinnenbein

Every joint of the walking legs and the pedipalps of the tarantula is equipped with at least 2 groups of proprioceptors. There is a total of 18 groups containing around 135 neurones. They lie at the most strategic points, i.e. right at the pivots, where stress and strain are maximal during movements. The greatest number, namely 5 groups, is to be found at the coxotrochanteral joint, a ball and socket joint that permits movements in nearly every plane. At least some of the receptor cells are multipolar.

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Verzeichnis der Abkürzungen Co Coxa - Fe Femur - Tr Trochanter - Pa Patella - T _i Tibia - M ₂ M. promoter trochanteris major (Bezeichnungen nach Dillon, 1952) - M ₄ M. levator trochanteris anticus - M ₅ M. depressor trochanteris medius - M ₇ M. depressor trochanteris obliquus - M ₈ M. remotor trochanteris ventralis - M ₉ M. remotor trochanteris dorsalis - M ₁₀ M. flexor femoris bilobatus - M ₁₁ M. flexor femoris longus - M ₁₂ M. flexor femoris dorsalis - M ₁₄ M. flexor patellae major - M ₁₅ M. flexor patellae robustus - M ₁₈ M. extensor femoris princeps - M ₁₉ M. flexor patellae minor - M ₂₀ M. extensor femoris posticus - M ₂₁ M. promotor tibiae - M ₂₂ M. remotor tibiae - M ₂₃ M. depressor tibiae anticus - M ₂₄ M. depressor tibiae posticus - M ₂₇ M. flexor tarsi anticus - M ₂₃ M. flexor tarsi posticus - M ₂₉ M. depressor praetarsi - S ₂₉ Sehne des M. depressor praetarsi - S ₃₀ Sehne des M. levator praetarsi Mit dankenswerter Unterstützung durch die Deutsche Forschungsgemeinschaft. Herrn Priv.-Doz. Dr. Hölldobler danken wir fur die Durchsicht des Manuskriptes, Herrn Dr. K. E. Linsenmair für die Überlassung einer Walzenspinne und Frau T. Hölldobler für die Hilfe bei der Ausführung der Zeichnungen.