The analysis, in marine ecology, of three-dimensional data matrices with one dimension of variable length

A method of defining a distance-measure is described for the case of a three-dimensional data-matrix with one dimension of variable length, e.g., sites by species by a variable number of specimens of each species in each site. Four independent distance-matrices are defined, concerning

1. (1) presence or absence,

2. (2) frequency,

3. (3) total quantity, and

4. (4) quantity of individual specimens of species when present.

Any or all of the four measures can be combined additively in any proportions the user wishes. The four separate measures, and the two combinations (1:1:1:1) and (1:2:3:4), are applied to a set of data from Bahamian coral reefs. It is shown that the (1:2:3:4) combination effectively summarizes, in a single analysis, the results of a number of separate exploratory analyses undertaken previously. The usefulness of such an analysis is briefly discussed.     

Some physical properties of pot-plant composts and their effect on plant growth

Summary The effect of peat and grit on the physical properties of composts made from soils of different structural properties has been examined. Peat was beneficial in giving improved physical properties to the composts, better vegetative growth of tomato and Antirrhinum and also earlier flowering with tomato. It had, however, no significant effect on the total yield of tomato fruit. Peat also eliminated a sterilizing toxicity in a chalky boulder clay.Measurement of macro-pore volume gave the best physical assessment of the mixtures with respect to vegetative growth, but the extent to which the improved growth was dependent on the physical property or to some inherent property of the peat has not been determined.Grit was not such a good physical conditioner from either a plant growth or physical point of view as peat. The size of the grit over the range 0.5–1.0 to 3.0–5.0 mm did not cause any significant change in the physical properties of mixtures when used in the proportions 60 soil, 25 well-granulated peat, 15 grit.     

Lysis of Lactococcus lactis subsp. cremoris SK110 and Its Nisin-Immune Transconjugant in Relation to Flavor Development in Cheese

To develop a nisin-producing cheese starter, Lactococcus lactis subsp. cremoris SK110 was conjugated with transposon Tn5276-NI, which codes for nisin immunity but not for nisin production. Cheese made with transconjugant SK110::Tn5276-NI as the starter was bitter. The muropeptide of the transconjugant contained a significantly greater amount of tetrapeptides than the muropeptide of strain SK110, which could have decreased the susceptibility of the cells to lysis and thereby the release of intracellular debittering enzymes.     

脑电信号数据压缩及棘波识别的小波神经网络方法

本文在对小波神经网络及其算法研究的基础上,提出了一种对脑电信号压缩表达和痫样脑电棘波识别的新方法。实验结果显示,小波网络在大量压缩数据的同时,能够较好的恢复原有信号,另外,在脑电信号的时频谱等高线图上,得到了易于自动识别的棘波和棘慢复合波特征,说明此方法在电生理信号处理和时频分析方面有着光明的应用前景。     

14-3-3 proteins double the number of outward-rectifying K+ channels available for activation in tomato cells

Outward-rectifying K+ channels are modulated in response to environmental stimuli by a range of intracellular factors, such as cytoplasmic Ca2+, pH, kinases and phosphatases. Here we report that voltage-dependent outward-rectifying K+ channels in tomato cells are also targets for modulation by 14-3-3 proteins. In whole-cell patch-clamp experiments, recombinant 14-3-3 protein (tomato isoform TFT7) was introduced into tomato cell protoplasts via the patch pipette. As a result the steady-state outward K+ current increased twofold and this increase was not dependent upon the presence of cytoplasmic ATP. A phosphorylated peptide that contained a phosphorylated 14-3-3 target-binding motif (RSTS*TP), derived from nitrate reductase, blocked the effect of 14-3-3, thus showing the specific nature of 14-3-3 action. Kinetic parameters of the conductance, like (de)activation kinetics, voltage dependence of gating and activation potential, were not significantly different between control and 14-3-3 infused cells. Analysis of single-channel activity and whole-cell noise indicated that the single-channel conductance was not affected by 14-3-3 infusion. We conclude that 14-3-3 proteins recruit 'sleepy' channels into a voltage-activatable state. The molecular mechanism underlying the 1 : 1 ratio of constitutively active and 14-3-3 recruited channels is discussed in the light of known functions of 14-3-3 dimers.     

Longitudinal proxy measurements in multiple sclerosis: patient-proxy agreement on the impact of MS on daily life over a period of two years

Background  

The use of self-report measurements in clinical settings is increasing. However, in patients with limitations that interfere with reliable self-assessment such as cognitive impairment or mood disturbances, as may be the case in multiple sclerosis (MS), data collection might be problematic. In these situations, information obtained from proxy respondents (e.g. partners) may replace self-ratings. The aim of this study was to examine the value of proxy ratings at separate points in time and to assess patient-proxy agreement on possible changes in disease impact of MS.     

Benthic freshwater nematode community dynamics under conditions of Tilapia aquaculture in Egypt

Studies of the influence of fish aquaculture on benthic freshwater nematode assemblages are scarce, but could provide a way of gauging environmental effects. The abundance and diversity of nematode assemblages in response to Oreochromis niloticus aquaculture were investigated in Kafr El-Sheikh Governorate, Egypt, from July to November 2014 under conditions of irrigation (reference), fish farm pond with high Tilapia density, and fish farm pond effluent canal without fish. The nematode genera Adoncholaimus, Punctodora, Labronema, Oncholaimus and Odontolaimus were present at all sites. Environmental factors were not related to nematode distribution patterns. Tilapia predation and/or disturbance may explain reduced nematode abundance, especially of the largest genera, Adoncholaimus, Punctodora and Labronema at the fish farm site. The absence of fish from the drainage site allowed intergeneric nematode competitive exclusion, benefitting the largest nematodes and reducing diversity indices.     

Synthesis,characterization and solution structure of tethered oligonucleotides containing an internal 3'-phosphoglycolate, 5'-phosphate gapped lesion

Bleomycins (BLMs) are antitumor antibiotics that in the presence of iron and oxygen mediate DNA damage by 4′-hydrogen atom abstraction of pyrimidines 3′ to guanines. The resulting 4′-deoxyribose radicals can be trapped by O₂ and ultimately result in the formation of base-propenal and gapped DNA with 3′-phosphoglycolate (3′-PG) and 5′-phosphate (5′-P) ends. The role of this lesion in triggering double-strand cleavage of duplex DNA by a single BLM molecule and the mechanism by which this lesion is repaired in vivo remain unsolved problems. The structure of these lesions is an essential step in addressing both of these problems. Duplex DNAs (13mers containing tethered hexaethylene glycol linkers) with GTAC and GGCC cleavage sites have been synthesized in which gaps containing 3′-PG and 5′-P ends at the sites of BLM cleavage have been inserted. The former sequence represents a hot spot for double-strand cleavage, while the latter is a hot spot for single-strand cleavage. Analytical methods to characterize the lesioned products have been developed. These oligonucleotides have been examined using 2D NMR methods and molecular modeling. The studies reveal that the lesioned DNAs are B-form and the 3′-PG and 5′-P are extrahelical. The base opposite the gap and the base pairs adjacent to the gap remain well stacked in the DNA duplex. Titrations of the lesioned GGCC oligomer with HOO-CoBLM leads to a mixture of complexes, in contrast to results of a similar titration with the lesioned GTAC oligomer.     

Some physical properties of pot plant composts and their effect on plant growth

Summary The growth and development of tomato, Potentate, in sand and soil separates having a range of air capacities has been studied.With the sand separates, an air capacity of 25 per cent gave optimum growth. Both the number of days to anthesis and the number of leaves produced before the first infloresence were negatively correlated with air capacity.Tomatoes grown in soil separates with base fertilizer added before prickingout showed an optimum air capacity requirement of 5 per cent. Plants in similar substrates and receiving a nutrient solution at each irrigation were less responsive to differences in air capacity over the range 1.9 to 20 per cent. Differences in the air capacity of the substrate had no effect on the number of leaves produced before the first inflorescence and little effect on the number of days to anthesis.     

Regulation of cytosolic phospholipase A(2) in a new perspective: recruitment of active monomers from an inactive clustered pool

cPLA(2) plays a key role in many signal transduction cascades by hydrolyzing arachidonic acid from membrane phospholipids. Tight control of cPLA(2) activity by a number of regulatory mechanisms is essential to its cellular function. We recently described the localization of cPLA(2) in clusters in fibroblasts and now propose that these clusters reflect a localized inactive pool from which active monomers can be recruited to keep cPLA(2) activity under control on the subcellular level. Using an electron microscopic in vitro approach, we show that cPLA(2) monomers, but not the clusters, bind to membranes in a Ca(2+)-dependent manner. This binding is accompanied by hydrolytic activity. The present data combined with our previous observation of a relative abundance of clusters over monomers in fixed fibroblasts [Bunt, G., de Wit, J., van den Bosch, H., Verkleij, A., and Boonstra, J. (1997) J. Cell Sci. 110, 2449-2459] gives rise to a concept of cPLA(2) regulation in which small amounts of active monomers are recruited to fulfill their function upon stimulation. This is in contrast to processes described for inflammatory cells, where a substantial part of the cytoplasmically localized cPLA(2) translocates to the perinuclear region upon stimulation to become active. Small-scale regulation of cPLA(2) by the proposed cluster-monomer cycle allows local and strictly confined control of cPLA(2) activity, apparently necessary for its cellular role in fibroblasts.