Natural selection and gynodioecy in Thymus vulgaris L.

Thymus vulgaris L. is a gynodioecious species with hermaphrodites (mF) and females (mS) widely distributed in southern France and in which reproduction of which is exclusively sexual. Numerous samples have been collected in the French Mediterranean region and the percentage of mS varies from 5 to 95% in different populations. By studying environmental conditions—the area covered at ground level by vegetation, stones and rocks—high percentages of mS are found to be related to a high vegetation cover and an absence or a scarcity of stones. Grasslands and old fields favour mS, while rocky sites favour mF. This relationship, which has been found both on the plains and on a mountain, is related to the most important reproductive characteristics of T. vulgaris —genetic control of male sterility, mode of pollination, percentage of selling and seed production. These relationships agree with the assumption that unstable environmental conditions such as grasslands or old fields in southern France favour maximum seed production and outcrossing. The greater stability of uncultivated areas such as rocky sites allows for the maintenance of autogamy. Consequently, it is natural selection which adjusts the percentage of male sterility in natural populations of Thymus vulgaris.     

Effects of Diurnal Changes in the Salinity of the Nutrient Solution on the Accumulation of Calcium by Tomato Fruit

Tomato fruit grown in diurnally fluctuating salinities (8 mScm^–1 during the day and 3 mS cm^–1 at night; 8/3mS cm^–1), accumulated the same amount of dry matter andmagnesium (Mg) as those in constant 3 or 8 mS cm^–1, butan intermediate amount of calcium (Ca). Raising the salinityof the nutrient solution by enriching with macronutrients orby adding NaCl had similar effects. The uptake of ⁴⁵Ca by tomato plants during the day was greaterthan at night and was reduced by salinity in both periods. Whilethe uptake of ⁴⁵Ca by 8/3 mS plants at night was similar tothat of 3 mS plants, the daily uptake was less than that in3 and 5.5 mS plants. The Ca content of tomato fruit increased with truss number at3 and 5.5 mS cm^–1 but not at 8/3 and 8 mS cm^–1.Within the same truss, the distal fruit had a lower Ca contentbut higher Mg content than the proximal fruit. The reductionin Ca content of the distal fruit at 8/3 mS cm^–1 was similarto that at 5.5 mS cm^–1. The Ca content of the tissue atthe distal end of the 8/3 mS fruit was lower than that of the5.5 mS fruit. Similarly, the distribution of ⁴⁵Ca to the distalhalf of the detached 8/3 mS fruit was less than that of 5.5mS fruit. A reduced uptake and inadequate distribution of Cato the truss and to the distal end of the 8/3 mS fruit werethe main causes of these differences. Lycopersicon esculentum(Mill.), tomato, fruit, calcium, magnesium, diurnal salinity     

The consequences of gynodioecy in natural populations of Thymus vulgaris L.

Summary Gene flow between the two sexual forms is asymmetrical in gynodioecious species: genes are transferred from male-fertile individuals (mF, hermaphrodites) to male-sterile individuals (mS, females) by pollen but from mS to MF individuals by diploid seeds. This situation is expected to cause differences in the genetic make up of mF and mS individuals. The expected differences were found in an experiment on a natural population of the gynodioecious species, Thymus vulgaris L. (thyme). The effectiveness of gynodioecy as a means of regulating heterozygosity and adaptability to various conditions of the environment is discussed.     

A unified model describing the role of hydrogen in the growth of desulfovibrio vulgaris under different environmental conditions

A unified model for the growth of Desulfovibrio vulgaris under different environmental conditions is presented. The model assumes the existence of two electron transport mechanisms functioning simultaneously. One mechanism results in the evolution and consumption of hydrogen, as in the hydrogen-cycling model. The second mechanism assumes a direct transport of electrons from the donor to the acceptor, without the participation of H2. A combination of kinetic and thermodynamic conditions control the flow of electrons through each pathway. The model was calibrated using batch experiments with D. vulgaris grown on lactate, in the presence and absence of sulfate, and was verified using additional batch experiments under different conditions. The model captured the general trends of consumption of substrates and accumulation of products, including the transient accumulation and consumption of H2. Furthermore, the model estimated that 48% of the electrons transported from lactate to sulfate involved H2 production, indicating that hydrogen cycling is a fundamental process in D. vulgaris. The presence of simultaneous electron transport mechanisms might provide D. vulgaris with important ecological advantages, because it facilitates a rapid response to changes in environmental conditions. This model increases our ability to study the microbial ecology of anaerobic environments and the role of Desulfovibrio species in a variety of environments. Copyright 1998 John Wiley & Sons, Inc.     

Electrolyte transport across rabbit late proximal colon in vitro

The second part of rabbit proximal colon was investigated in vitro under short circuit conditions. Unidirectional sodium and chloride fluxes were measured during the soft faeces period and during the hard faeces period. Rabbit late proximal colon has a potential difference (psi mS) of 4 mV, a tissue conductance (GT) of 10-11 mS/cm2 and a short circuit current (Isc) of 1.5 mueq/cm2 X hr. Under control conditions sodium (2.65 mueq/cm2 X hr) and chloride (0.67 mueq/cm2 X hr) are absorbed. Ouabain abolished psi ms,Isc and the net sodium flux totally, whereas 0.1 mM amiloride only slightly decreased the net sodium flux. No differences in electrical properties and Na,Cl-fluxes were found between the faeces periods. Removal of sodium abolished psi ms and Isc totally, and a high potassium solution depolarized the preparation (psi ms = 0). A linear current-voltage relation characterizes the tissue as an ohmic resistor between -40 and +50 mV, and reveals a slope conductance of 14 mS/cm2 under KCl conditions. We conclude that the transport functions under in vitro conditions differ markedly from the in vivo situation, and that the diurnal differences of electrolyte transport in vivo occur mainly by the involvement of ionic gradients.     

Effect of the C-terminus of murine S100A9 protein on experimental nociception

Calcium-binding protein S100A9 induces antinociception in mice evaluated by the writhing test. Similarly, a peptide identical to the C-terminus of murine S100A9 (mS100A9p) inhibits the hyperalgesia induced by jararhagin, a metalloprotease. Thus, we investigated the effect of mS100A9p on different models used to evaluate nociception. mS100A9p induced a dose-dependent inhibitory effect on the writhing test, and on mechanical hyperalgesia induced by carrageenan. mS100A9p inhibited thermal hyperalgesia induced by carrageenan. mS100A9p did not modify the nociceptive response in hot plate or tail-flick tests. These data demonstrate that the C-terminus of S100A9 protein interferes with control mechanisms of inflammatory pain.     

Antinociceptive effect of the C-terminus of murine S100A9 protein on experimental neuropathic pain

The synthetic peptide identical to the C-terminus of murine S100A9 protein (mS100A9p) has antinociceptive effect on different acute inflammatory pain models. In this study, the effect of mS100A9p was investigated on neuropathic pain induced by chronic constriction injury (CCI) of the sciatic nerve in rats. Hyperalgesia, allodynia, and spontaneous pain were assessed to evaluate nociception. These three signs were detected as early as 2 days after sciatic nerve constriction and lasted for over 14 days after CCI. Rats were treated with different doses of mS100A9p by intraplantar, oral, or intrathecal routes on day 14 after CCI, and nociception was evaluated 1h later. These three routes of administration blocked hyperalgesia, allodynia and spontaneous pain. The duration of the effect of mS100A9p depends on the route used and phenomenon analyzed. Moreover, intraplantar injection of mS100A9p in the contralateral paw inhibited the hyperalgesia on day 14 days after CCI. The results obtained herein demonstrate the antinociceptive effect of the C-terminus of murine S100A9 protein on experimental neuropathic pain, suggesting a potential therapeutic use for it in persistent pain syndromes, assuming that tolerance does not develop to mS100A9p.     

The C-terminus of murine S100A9 inhibits hyperalgesia and edema induced by jararhagin

The effect of a synthetic peptide (H92-G110) identical to the C-terminus of murine S100A9 (mS100A9p) was investigated on hyperalgesia and edema induced by either jararhagin or papain in the rat paw. mS100A9p not only reverted hyperalgesia and edema induced by jararhagin, but also the highest concentration induced antinociception. Hemorrhage induced by jararhagin and its hydrolytic activity were inhibited by mS100A9p. These data suggest that mS100A9p might block jararhagin-induced hyperalgesia and edema by inhibiting jararhagin catalytic activity, since papain-induced hyperalgesia and edema were not inhibited by mS100A9p.     

Na+ transport and impedance properties of cultured renal (A6 and 2F3) epithelia

Previous impedance analysis studies of intact epithelia have been complicated by the presence of connective tissue or smooth muscle. We now report the first application of this method to cultured epithelial monolayers. Impedance analysis was used as a nondestructive method for deducing quantitative morphometric parameters for epithelia grown from the renal cell line A6, and its subclonal cell line 2F3. The subclonal 2F3 cell line was chosen for comparison to A6 because of its inherently higher Na+ transport rate. In agreement with previous results, 2F3 epithelia showed significantly higher amiloride-sensitive short-circuit currents (Isc) than A6 epithelia (44 +/- 2 and 27 +/- 2 microA/cm2, respectively). However, transepithelial conductances (GT) were similar for the two epithelia (0.62 +/- 0.04 mS/cm2 for 2F3 and 0.57 +/- 0.04 mS/cm2 for A6) because of reciprocal differences in cellular (Gc) and paracellular (Gj) conductances. Significantly lower Gj and higher Gc values were observed for 2F3 epithelia than A6 (Gj = 0.23 +/- 0.02 and 0.33 +/- 0.04 mS/cm2 and Gc = 0.39 +/- 0.16 and 0.26 +/- 0.10 mS/cm2, respectively). Nonetheless, the cellular driving force for Na+ transport (Ec) and the amount of transcellular Na+ current under open-circuit conditions (Ic) were similar for the two epithelia. Three different morphologically-based equivalent circuit models were derived to assess epithelial impedance properties: a distributed model which takes into account the resistance of the lateral intercellular space and two models (the "dual-layer" and "access resistance" models), which corrected for impedance of small fluid-filled projections of the basal membrane into the underlying filter support. Although the data could be fitted by the distributed model, the estimated value for the ratio of apical to basolateral membrane resistances was unreasonably large. In contrast, the other models provided statistically superior fits and reasonable estimates of the membrane resistance ratio. The dual-layer model and access resistance models also provided similar estimates of apical and basolateral membrane conductances and capacitances. In addition, both models provided new information concerning the conductance and area of the basolateral protrusions. Estimates of the apical membrane conductance were significantly higher for 2F3 (0.79 +/- 0.23 mS/cm2) than A6 epithelia (0.37 +/- 0.07 mS/cm2), but no significant difference could be detected for apical membrane capacitances (1.4 +/- 0.04 and 1.2 +/- 0.1 microF/cm2 for 2F3 and A6, respectively) or basolateral membrane conductances (3.48 +/- 1.67 and 2.95 +/- 0.40 mS/cm2). The similar basolateral membrane properties for the two epithelia may be explained by their comparable transcellular Na+ currents under open-circuit conditions.     

The effect of pH on feeding behaviour in newt larvae (Triturus: Amphibia)

The feeding responses of three species of newt larvae were compared under circumneutral and sublethal acid conditions. Under acid conditions (pH 4.5) feeding behaviour was suppressed in palmate newts, Triturus helveticus, and smooth newts. T. vulgaris , but not in crested newts, T. cristatus. At low pH, approach and orientation towards food occurred in T. helveticus and T. vulgaris , but snapping was inhibited; T. cristatus snapped and consumed food immediately it was offered under the same conditions. These differences are not consistent with the apparent greater tolerance of T helveticus for acidified ponds. The observations suggest that the chemosensory system of T. helveticus and T. vulgaris may be impaired at low pH.     

Inhibition of the catalase activity from Phaseolus vulgaris and Medicago sativa by sodium chloride.

Changes in catalase activity during the development of the Rhizobium-legume symbiosis as well as its response in salinized plants of Phaseolus vulgaris and Medicago sativa, was studied. Besides, it was examined the behavior of the enzyme, isolated from leaves and root nodules, during in vitro incubation with NaCl doses. Nodule catalase activities of both legumes were assayed with several enzyme inhibitors and also purified. Leaf catalase activity of Phaseolus vulgaris and Medicago sativa decreased and increased respectively throughout the ontogeny, but root nodule catalase kept a high and stable value. This last result suggests that both legumes require the maintenance of high nodule catalase in nitrogen-fixing nodules. Under salt stress conditions leaf and nodule catalase activity decreased in both, grain and pasture legumes. Because catalase from leaf of Medicago sativa and nodules of Phaseolus vulgaris were relatively sensitive to NaCl during in vitro experiments, the detoxifying role of this enzyme for H(2)O(2) should be limited in such conditions. Both catalases, from determinate and indeterminate nodules, were affected neither by oxygen nor superoxide radicals but showed a strong (Phaseolus vulgaris) or partial (Medicago sativa) inhibition with dithiothreitol, dithionite and beta-mercaptoethanol. Besides, cyanide was the most potent inhibitor of nodule catalases. Finally, catalases partially purified by immobilized metal ion affinity chromatography migrated at 42 (Phaseolus vulgaris) and 46kDa (Medicago sativa) on SDS-PAGE, whereas native forms on sephacryl S-300 columns exhibited a molecular mass of 59 and 48kDa (Phaseolus vulgaris) and 88 and 53kDa (Medicago sativa).     

Effect of high zinc concentrations on the growth of Stichococcus bacillaris and Chlorella vulgaris

The effect of concentrations of zinc from 50 to 400 mg/l on the growth of Stichococcus bacillaris and Chlorella vulgaris under laboratory conditions was examined. The growth of both species was inhibited in proportion to the concentration of the metal in the medium. S. bacillaris was more tolerant to high zinc concentrations than C. vulgaris. Microscopical examination of cells growing in medium with zinc did not reveal any significant changes compared to the control cultures.     

毛乌素沙地沙地柏(Sabina vulgaris)的水分生态初步研究

对毛乌素沙地沙地柏群落的水分状况作了初步研究。在典型的沙地柏群落中选取位于丘顶（水分条件较差）和丘间低地（水分条件较好）的两个样地作为研究对象,观测了植物叶子的蒸腾速率、气孔阻力及水势等生理生态指标,并结合群落特征和土壤水分状况,探讨了水分亏缺对沙地柏的影响。研究结果表明：１）虽然沙地柏具有比多数沙生灌木较小的蒸腾速率和更强的抗旱性,但是在不能利用地下水的情况下,其过大的密度可引起大量蒸腾耗水,并使植物处于严重的水分亏缺之中;２）在沙地柏群落的退化乃至于成片枯死过程中,水分胁迫是重要的因素之一;３）为了防风固沙,人工栽植沙地柏的适宜地段应选择水分条件较好的沙地（如滩地覆沙）,而在高大的沙丘或梁地栽植沙地柏,应该注意规模和密度。     

PHYSIOLOGICAL CHARACTERIZATION OF SIX LIPID-PRODUCING DIATOMS FROM THE SOUTHEASTERN UNITED STATES1

Six strains of diatoms from intertidal waters were isolated as part of the SERI Aquatic Species Program collection and screening effort: Amphiprora hyalina Greville, Cyclotella cryptica Reimann, Lewin & Guillard, Navicula acceptata Hustedt (two strains, NAVIC6 and NAVIC8), Navicula saprophila Lange-Bertalot & Bonik, and Nitzschia dissipata (Kütz.) Grunow. Among numerous algal strains isolated as part of this collection effort, these six strains showed rapid growth and elevated lipid content in preliminary screening experiments and were chosen for further physiological characterization. N. dissipata grew most rapidly at 25°C, whereas the other five strains grew best at 30–35°C. Salinity tolerance varied among strains, with maximal growth occurring at the following conductivities: 10–60 mS.cm^?1 (A. hyalina and N. acceptata NAVIC8), 10–35 mS.cm^?1 (C. cryptica), 20–45 mS.cm^?1 (N. acceptata NAVIC6), 10 mS.cm^?1 (N. saprophila), and 20–35 mS.cm^?1 (N. dissipata). The diatoms also differed in their utilization of nitrogen sources with A. hyalina growing optimally with either nitrate or urea; N. acceptata NAVIC6, with either nitrate or ammonium; C. cryptica, N. acceptata NAVIC8, and N. dissipata, with nitrate; and N. saprophila, with urea. Under optimal conditions, A. hyalina grew at 2.0 doublings. day^?1; C. cryptica grew at 3.0 doublings. day^?1. Each Navicula strain had a growth rate of 3.8 doublings. day^?1, and N. dissipata grew at 2.6 doublings.day^?1. All six strains had lipid contents in excess of 37% ashfree dry weight (AFDW) under nutrient-limited conditions, with N. saprophila having the highest lipid content at 48% AFDW.     

Biochemical characterization of the murine S100A9 (MRP14) protein suggests that it is functionally equivalent to its human counterpart despite its low degree of sequence homology.

Due to the low degree of sequence similarity it has been speculated that murine and human S100A9 (MRP14), an inflammatory marker protein belonging to the S100 protein family, may have different cellular functions in mouse and man. The present study was undertaken to investigate the murine S100A9 protein (mS100A9) biochemically. We demonstrate that in murine peripheral CD11b+ cells up to 20% of the protein of the cytosolic fraction consists of mS100A9 and that several minor mS100A9 isoforms are present. Cell fractionation experiments with CD11b+ murine leukocytes showed that mS100A9 is found in the cytosol as well as in the insoluble fraction. Transient expression of a green fluorescence protein-mS100A9 fusion in mammalian cells revealed that mS100A9 is localized in neither the nucleus nor the vesicles. Recombinantly expressed murine S100A9 interacts in vitro with murine and human S100A8 in an in vitro glutathione S-transferase pull-down assay. Homodimerization was not observed. For further biochemical analysis the myeloid 32D cell line is presented as a suitable model, to study murine myeloid expressed S100 proteins. Both murine S100A9 and its dimerization partner mS100A8 are expressed at the onset of granulocyte-colony stimulating factor induced myeloid differentiation. Substantial amounts of this complex are constitutively secreted by granulocytic 32D cells into the medium. In summary, these data suggest, that the human and murine S100A9 may share a higher degree of functional homology than of sequence similarity.     

寄主大豆对根结瘤的控制

我国９个大豆（ＧｌｙｃｉｎｅｍａｘＬ．Ｍｅｒｒ．）品种感染根瘤菌ＵＳＤＡ１１０后,产生不同的结瘤数,低者在２０个以下．高者在６０个以上。赤豆、绿赤豆也可被感染结瘤,而豇豆、扁豆则不能。超结瘤大豆ｎｔｓ３８２作为接穗时能诱导我国大豆原结瘤数有４５个的开育１０号、原结瘤数有１２个的大黄分别发生高结瘤。ｎｔｓ３８２作为砧木时,则不能表现超结瘤．表明超结瘤因子能传给我国大豆,反之存在于我国大豆中的限制超结瘤的因子也能传给ｎｔｓ３８２。ｎｔｓ３８２于ＮＯ３－环境中仍表现超结瘤的特点也能导入开育１０号、大黄及赤豆根部,并使之在ＮＯ３－环境中结瘤。在ＮＯ３－环境中不能结瘤的开育１０号作为接穗,ｎｔｓ３８２作为砧木的嫁接植株,于子叶生长阶段接受ＮＯ３－时,仍能结瘤,于真对生长时接受ＮＯ３－时．则不能结瘤,表明限制结瘤因子于真叶细胞中被诱导形成。     

普通小球藻对养殖污水脱氮除磷的效果研究

随着我国养殖业的不断发展,养殖污水排放量的日益增加,养殖污水的高氮、磷含量导致水体富营养化问题日趋严重。小球藻是光能自养生物,能有效同化氮、磷,使污水中的氮、磷减少。本研究通过在实验室模拟不同氮、磷含量的养殖污水环境,分析小球藻对氮、磷的去除效果;在此基础上,用小球藻处理某养殖场污水;并联合膨润土与小球藻,探究两者脱氮除磷的协同作用能力及膨润土对小球藻细胞沉降的效果。结果表明,小球藻对模拟污水的氨氮去除率可达80%,对磷酸根的最高去除率接近100%;对养殖污水中的氮、磷也有一定的去除效果;但养殖污水成分复杂,小球藻的生长被抑制。膨润土与小球藻的结合,能够提高污水中的氮磷去除率并帮助藻细胞快速沉降,为污水处理后藻细胞的收集处理提供了有效方法。     

Amide 1 Expression in Psoriasis and Lichen Planus using Synchrotron Infrared Microspectroscopy

Psoriasis vulgaris and, Lichen planus are cutaneous inflammatory conditions that usually exhibit distinctive morphology. Ten psoriasis vulgaris and, ten Lichen planus patients (mean age, 45 ± 10.27 years) with confirmed histopathological diagnoses were analyzed. In the current study synchrotron infrared (IR) microspectroscopy was used to differentiate between these two conditions based on their lymphocytic proteins analyses. It was found that β-sheets protein structure, known to represent cell apoptosis, were expressed significantly in Lichen planus conditions than that of the psoriasis vulgaris when analyzed against the established normal control groups of five patients of comparable age and, genders (P = 0.001, 0.03 respectively). Also, the amide 1 protein type within the epidermis of Lichen planus were expressed in significant proportions as compared to psoriasis vulgaris (P < 0.001). On the contrary, the amide 1 protein structural types were found clustered in psoriasis vulgaris in different IR spectra than that in Lichen planus as observed in a number of patients during this study. These observations indicated that the concentration of amide 1 protein in psoriasis vulgaris varies to that of Lichen planus. In conclusion, both psoriasis vulgaris and, Lichen planus have different types of epidermal and, dermal protein structures and, this information can be of clinical diagnostic and therapeutic use for these cutaneous inflammatory conditions in near future.