A mathematical model for the light affected system in the drosophila eclosion rhythm

This paper describes some analytical models for the system which regulates the daily eclosion rhythm of the drosophila. A general topological model is described which can simulate practically all the known experimental results about the behavior of the system under various light stimuli. From that a more specific model is proposed which can shortly be described as follows: The system contains a basic oscillator whose output is a substances. This is produced in the presence of an enzymer. During part of the cycler is deactivated ands dissipates until it reaches a lower level whenr is reactivated again. Light has the effect of deactivatingr immediately. The substances causes the production of a second substanceq which triggers a series of reactions leading to eclosion when it exceeds a threshold. The main oscillator (s—r) is temperature-compensated, but the production ofq is accelerated in the presence of light or higher temperature.     

Genetic changes in a barley population analyzed in terms of some life cycle components of selection

A bulk-hybrid population of barley (CC-XXI) was investigated for changes over a period of six generations, in (1) generation means and variances for three quantitative characters (2) phenotypic and genotypic frequencies at several marker loci and (3) the components of selection at several life cycle stages (germination and seedling survival, fertility, fecundity) for the dominant-recessive phenotypic classes at three of the above loci. The changes in mean and variance for the quantitative characters appeared to be due to both directional and stabilizing types of selection. The estimates of selective values from frequency data suggested heterozygote advantage along with unequal homozygote fitnesses at locuss and heterozygote disadvantage at locibl, r andv, from computations based on higher outcrossing rates in the presence of male-steriles.Of the components studied, fertility and fecundity appeared to account for a larger portion of the total selective differential than the pre-adult stages (germination and seedling establishment). Net selective values based on component analysis approximated the selective values obtained from the frequency data for locusr. For locis, andv, however, the two estimates were often quite different, although they generally agreed in direction. The discrepancies between the two sets of estimates were discussed in terms of the complexity of overall measures of fitness.     

Deduction of pulmonary microvascular hematocrit from indicator dilution curves

We have developed a new model describing the relationship between plasma and red cell tracers flowing through the lung. The model is the result of an analysis of the transport of radiolabeled plasma albumin between two flowing phases and shows that differences between red cell and plasma tracer curves are related to microvascular hematocrit. The model was tested in an isolated, blood-perfused dog lung preparation in which we injected⁵¹Cr-labeled red cells and¹²⁵I-labeled plasma albumin into the pulmonary artery. From the tracer concentration-time curves at the venous outflow, we calculatedh _r, the ratio of microvascular hematocrit to large-vessel hematocrit. In 18 baseline experiments,h _r=0.92±0.01 (mn±sem) at a blood flow rate of 10.7±0.3 ml s⁻¹. We determined the effects of (a) glass bead embolization, (b) alloxan, and (c) lobe ligation onh _r. Embolization attenuated the separation between plasma and red cells (increasedh _r), probably as a consequence of passive vasodilation. Alloxan enhanced separation of plasma and red cells (decreasedh _r), possibly as a result of arteriolar vasoconstriction. Ligation of a fraction of the perfused tissue at constant flow did not cause significant change inh _r in the remaining perfused tissue. The model assumes that large-vessel transit times are uniform and that all dispersion occurs in the microvasculature. A theoretical analysis apportioning dispersion between large and small vessels disclosed that the error associated with these assumptions is likely to be less than 15% of the measuredh _r. We conclude from this study that the microvascular hematocrit model describes experimental plasma and red cell curves. The results imply thath _r can be readily deduced from tagged red cells and plasma and can be accounted for in calculating permeability-surface area in diffusing tracer experiments.     

Contribution to the linkage theory of autopolyploids: I

A theory of linkage of autopolyploids is developed under consideration ofm loci andr alleles. The simplifying assumption of chromosome segregation, which may be considered as an approximation to the more adequate theory of chromatid segregation, is made throughout. Random mating and distinct, non-overlapping generations are assumed. Under these assumptions the problem is determined by three basic probability distributions—the distributions of genotypes and of gametes, and the segregation distribution. The segregation distribution is assumed to be the same for males and for females. The aim of the paper is to establish recurrence formulas (which allow to find the distributions of gametes and of genotypes from generation to generation, if the distribution of genotypes for an initial generation is known) and to investigate the limit behavior of these distributions as the number of generations increases indefinitely. In the present paper (hereafter referred to as I) the problem is explained, and the three characteristic distributions are introduced for the general case of a 2s-ploid,m loci, andr alleles. Recurrence relations are established for tetraploids,s=2 andm=2 loci, while the recurrence relations for the general case as well as the limit theorems will be given in the second part of this paper (hereafter referred to as II).     

Validity of Global Physical and Emotional SUDS

Despite the wide-spread use of Subjective Units of Discomfort Scales, or SUDS, to measure anxiety to specific stimuli, little information has been published on the validity of such scales and even less on their use as global measures of emotional and physical discomfort. Data was examined for 182 consecutive admissions to a psychology clinic to determine the relationship of self-rating of emotional and physical discomfort to one another and of the emotional self-rating to the clinician rating of general functioning (GAF). As expected, patients’ ratings of their emotional discomfort were significantly higher than ratings of their physical discomfort (t = 9.077, p < .001). Emotional SUDS were significantly and negatively related to clinicians’ GAF ratings (r = − 0.439, p < .001), indicating that the two ratings measured related global constructs. Data for the 53 patients who also completed the MMPI-2 was drawn from the larger sample to determine the nature of the relationship between SUDS and two measures of general emotional distress, with patients’ SUDS significantly related to both the A scale (r = 0.351, p < .05) and the neurotic index (r = 0.366, p < .01). Finally, there was a significant decrease in the emotional SUDS (t = 4.686, p < .001) but not the physical SUDS (t = 0.788, p = .434) after 3 months of psychotherapy. The data supports SUDS as global measures of both physical and emotional discomfort.     

Morphometric relationships for some species of elasmobranch from tropical eastern Pacific

This study proposes length relationship equations to determine total length of four species of sharks (Carcharhinus falciformis, Mustelus lunulatus, Sphyrna lewini and Carcharhinus limbatus) based on trunk lengths (TrL) and interdorsal lengths (IL) caught in Colombia and Central America Pacific Ocean. In Central American Pacific, data were recorded for C. falciformis, C. limbatus and S. lewini between 2006 and 2012. In the Colombian Pacific, data was recorded in 1994–1995 and from 2006 to 2012 for C. falciformis, S. lewini and M. lunulatus. In the Central American Pacific the IL – TL relationship was acceptable for C. falciformis (r² = .69) and C. limbatus which presented a good relationship (r² = .81) where most specimens were juveniles; the same trend was found for S. lewini (r² = .96). The TL‐TrL relationship estimated for species caught in the Colombian Pacific was significant for C. falciformis (r² = .98) and for M. lunulatus (r² = .84); however, for S. lewini this relationship was low (r² = .55). Results indicate this is a useful tool for fishery statistics and fishery management for elasmobranch species of the Eastern Tropical Pacific.     

Surface energy fluxes and control of evapotranspiration from a <Emphasis Type="Italic">Carex lasiocarpa</Emphasis> mire in the Sanjiang Plain,Northeast China

Data from four components of the radiation balance were used to investigate the surface energy budgets for a Carex lasiocarpa mire in the Sanjiang Plain, Northeast China, and the controlling factors of the evapotranspiration (ET) were discussed in detail. During the growing season 2006, the shortwave radiation (SW↓) reaching the mire surface added up to 2,854.3 MJ m⁻² and the net radiation (Rn) was 1,637.4 MJ m⁻² in total, with an average of 9.86 MJ m⁻² day⁻¹. G was the smallest flux at the water-atmosphere interface, with an average of about 0.91 MJ m⁻² day⁻¹, but showed high relative variability, even changing its sign. The latent and sensible heat fluxes (LE and H) amounted to 787.48 and 476.26 MJ m⁻², respectively, and the total sum of LE and H accounted for 77.18% of Rn. By conversion from LE, the average value of ET from the mire was 1.84 mm day⁻¹, amounting to 298.8 mm. The total ET was almost 60% of the total rainfall in the same period, proving that ET is the primary water consumer in the mire. The growth of C. lasiocarpa was related closely with surface resistance (r _s), and analysis of partial correlation indicated that r _s correlated negatively with leaf area index (LAI) when the interference of the available energy, Rn-G, was removed. There was a strong linkage between r _s and the evaporative fraction [LE/(LE + H)] as well as Bowen ratio (β). r _s was the key factor in controlling the variation of ET and regulating energy partitioning between LE and H. During the whole growing season, r _s and R _n−G were the two main factors coupled in ET processes. In spring, r _s dominated ET processes, and the increase in LAI led to a decrease in r _s, which in turn accelerated ET as vegetation developed until late August. After August, the available energy controlled the process of ET completely until ET reached an equilibrium in mid-October.     

Molecular cytogenetic evidence for a high level of chromosome pairing among different genomes in Triticum aestivum–Thinopyrum intermedium hybrids

Intergeneric hybrids (ABDJJ^sS genomes) were made between Triticum aestivum cv. Chinese Spring (CS) and Thinopyrum intermedium. Genomic in situ hybridization (GISH) using genomic DNA probes from Pseudoroegneria libanotica (Hackel) D.R. Dewey (genome S, 2n = 14) was used to study chromosome pairing among J, J^s, S and wheat ABD genomes in the hybrids. It was shown that in the hexaploid (ABDJJ^sS) hybrids, high pairing occurred among wheat chromosomes and among Thinopyrum chromosomes. A closer relationship was observed among the three genomes of Th. intermedium than among the three genomes of T. aestivum. It was further discerned that S genome chromosomes paired with J- and J^s-genome chromosomes at a high frequency. The frequency of heterologous pairing between S and J or S and J^s chromosomes was higher than those between J and J^s chromosomes, indicating that the S-genome was more closely related with these two genomes. Our results provided direct molecular cytogenetic evidence for the hypothesis that S-genome chromosomes are genetically similar to the J-genome chromosomes and, therefore, genetic exchange between these genomes is possible. The discovery of a close relationship among S, J and J^s genomes provides valuable markers for molecular cytogenetic analyses using S-genomic DNA probes in monitoring the transfer of useful traits from Thinopyrum species into wheat. Received: 23 August 2000 / Accepted: 5 September 2000     

Weak relationship between ionized and total magnesium in serum of patients requiring magnesium status

Measurement and monitoring of magnesium (Mg) are important to prevent the development of serious and potentially fatal complications in critically ill patients. Although ion-selective electrodes are available and earlier reports suggest that free ionized magnesium (iMg²⁺) is the most useful test to estimate Mg status, most clinical laboratories still only measure total Mg. To compare the relationship among iMg²⁺, total Mg, and albumin in serum, samples were collected from 48 consecutive patients admitted to an intensive care unit or a primary health center. The mean serum level of iMg²⁺ in 44 patients was 0.53 mmol/L, the total Mg was 0.06 mmol/L, and the albumin was 34.93 g/L. The correlation between iMg²⁺ and total Mg in serum was r=0.585; the correlation between iMg²⁺ and albumin in serum was r=378; and the correlation between total Mg and albumin in serum was r=0.340. The mean percent iMg²⁺ in relation to total Mg in serum was calculated to be 55% in the patient samples. The important level of biologically active iMg²⁺ was not reflected upon analysis of total Mg in 25% of consecutive patients. This report shows that the correlation of iMg²⁺ and total Mg is weak, not only in critically ill patients but also in patients in whom Mg status is inquired as a whole.     

Proteomic profiling and characterization of differential allergens in the nematodes Anisakis simplex sensu stricto and A. pegreffii

The parasite species complex Anisakis simplex sensu lato (Anisakis simplex sensu stricto; (A. simplex s.s.), A. pegreffii, A. simplex C) is the main cause of severe anisakiasis (allergy) worldwide and is now an important health matter. In this study, the relationship of this Anisakis species complex and their allergenic capacities is assessed by studying the differences between the two most frequent species (A. simplex s.s., A. pegreffii) and their hybrid haplotype by studying active L3 larvae parasiting Merluccius merluccius. They were compared by 2D gel electrophoresis and parallel Western blot (2DE gels were hybridized with pools of sera from Anisakis allergenic patients). Unambiguous spot differences were detected and protein assignation was made by MALDI‐TOF/TOF analysis or de novo sequencing. Seventy‐five gel spots were detected and the corresponding proteins were identified. Differentially expressed proteins for A. simplex s.s., A. pegreffii, and their hybrid are described and results are statistically supported. Twenty‐eight different allergenic proteins are classified according to different families belonging to different biological functions. These proteins are described for the first time as antigenic and potentially new allergens in Anisakis. Comparative proteomic analyses of allergenic capacities are useful for diagnosis, epidemiological surveys, and clinical research. All MS data have been deposited in the ProteomeXchange with identifier PXD000662 ( http://proteomecentral.proteomexchange.org/dataset/PXD000662 ).     

克里雅河流域荒漠-绿洲交错带3种不同生活型植物的光合特性

利用LI-6400光合仪测定新疆克里雅河流域荒漠-绿洲交错带自然生长的芦苇、柽柳、胡杨叶片的气体交换参数及环境影响因子,通过对比3种植物光合特性的差异及其与环境因子间的关系,探讨3种植物对荒漠环境的适应特性和机制。结果表明:(1)3种植物叶片Pn日变化均呈不对称的双峰曲线,"午休"现象明显,Pn日均值的大小依次为胡杨芦苇柽柳,种间差异不显著。(2)Tr、PAR和Gs与3种植物Pn的日变化存在极显著或显著的相关关系,其中影响芦苇Pn的主要因子是Tr、PAR和Gs,作用效应为TrGsPAR;影响柽柳Pn的主要因子是Tr、Gs,作用效应为TrGs;影响胡杨Pn的主要因子是Tr。(3)3种植物的光合作用对光强和CO2的响应特征可用二次方程描述;光补偿点和饱和点均为柽柳胡杨芦苇;CO2补偿点为胡杨柽柳芦苇,饱和点为胡杨芦苇柽柳。(4)3种植物的表观量子效率在0.0341—0.0411 mol/mol之间,羧化效率在0.0480—0.0546 mol m-2s-1之间。综合比较表明,3种干旱区植物在自然条件下日均净光合速率、光能利用率和CO2同化能力差异不显著,气孔限制是光合"午休"现象产生的主要原因;影响3种植物光合作用的主导因子各不相同,但Tr与Pn间的关系较其它因子更为密切。     

Assignment of the complement serine protease genes C1r and C1s to chromosome 12 region 12p13

Summary C1r and C1s are distinct, but structurally and functionally similar, serine protease zymogens responsible for the enzymatic activity of the first component of complement (C1). Recent comparisons indicate a significant degree of sequence similarity between C1r and C1s and support the hypothesis that they are related by gene duplication. Complementary DNA probes for human C1r and C1s do not cross-hybridize even at mild stringency conditions and are therefore genespecific. Using a panel of 25 human-rodent cell hybrids, we have independently assigned the C1r and the C1s genes to chromosome 12. In situ hybridization analyses were consistent with these assignments, showing in addition that both C1r and C1s are located on the short arm of the chromosome in the region p13. These data suggest that the homologous C1r and C1s genes have remained closely linked after duplication of a common ancestor. The C1r and C1s loci also provide useful polymorphic DNA markers for the short arm of chromosome 12.     

Enantioselective autocatalysis. III. Configurational and conformational studies on a 1,4-benzodiazepinooxazole derivative

We report here on configurational and conformational studies undertaken on the bromofluoro-1,4-benzodiazepinooxazole derivative I, which has previously been found capable of undergoing total spontaneous resolution under racemizing conditions. Due to its bridgehead N-atom I may exist in any of four diastereomeric forms,C _r N _r (orC _s N _s ) andC _r N _s (orC _s N _r ). Molecular mechanics calculations revealed that in their lowest energy conformations theC _r N _r (orC _s N _s ) diastereomers were favored over theC _r N _s (orC _s N _r ) diastereomers by some 3.42 kcal/mol, while semi-empirical quantum mechanical calculations indicated heats of formation also favoring theC _r N (orC _s N _s ) diastereomers by 3.83 kcal/mol. The¹H NMR spectra of the three crystalline modifications (, and) of I were examined in acetone, and found to be identical. These data, combined with the results of the above calculations, suggest that I exists in methanol or methanol-acetone solutions as theC _r N (orC _s N _s ) enantiomer prior to its racemization.     

Transmission of Bacteriocinogenicity by Conjugation in Group D Streptococci

Seventy-seven out of eighty-one group D streptococcal strains isolated from humans and animals were found to produce bacteriocins that were active on other streptococcal strains of gorup A and D, but inactive on their own cells. On the bases of the spectra of indicator strains, and the sensitivities to heat, chloroform, and trypsin, seven types of bacteriocins were classified. Streptococcus faecalis var. liquefaciens strain 4532 or strain A (liq-A) was UV-irradiated, and mutants which lost bacteriocin- as well as the β-hemolysin-forming activities (Bact^–.Hem^–) were obtained. Cells of the type I bacteriocin producer (SM^r.TC^r.Bact-I⁺.Hem⁺) and nonproducer 2025 (PC^r.Bact-I^–.Hem^–), both belonging to S. faecalis var. liquefaciens, were mixed and incubated in broth. Recombinants (PC^r.-SM^s.TC^s.Bact-I⁺.Hem⁺) were obtained at a high frequency (5.8% preinoculum size of PC^r.-Bact-I^–.Hem^–), and the character was stable for at least ten transfers. In the mixed culture, a marked decrease in the recipient 2025 cell number was observed. The occurrence of recombinants was not inhibited by deoxyribonuclease. A cell-free filtrate of Bact⁺.Hem⁺ cells mixed with Bact^–.Hem^– cells did pot cause a mutation of the latter combined characters. The transfer of a genetic marker is discussed as an event of the cell-to-cell contact.     

A vegetative instability inAspergillus nidulans

A proportion of segregants from a cross between strainsbi ₁w₃s₅ andy pyro ₄s₁₂ were found to be unstable. The sectors to which they gave rise during vegetative growth, made up about 30% of all segregants from such crosses. Only thes ₁₂ alleles appeared to be genetically affected. From the pattern of inheritance, and the range of sectors observed, the probable cause of the instability is a chromosomal aberration. p-fluorophenylalanine, which is used to haploidise diploid strains, induces potentially unstable segregants to sector with great efficiency. Since the instability is probably due to an aberration, this amino acid analogue must also be an inducer, either of aberrations or, under certain circumstances, recombination.This work was completed at Trinity College, Dublin in the Summer of 1966.     

长三角典型水稻土有机碳组分构成及其主控因子

准确把握水稻土有机碳组分构成特征及其主控因子,对定量化评价土壤有机碳质量和未来演变趋势具有重要意义。通过室内土壤呼吸培养实验结合有机碳三库一级动力学方程,模拟得到长三角地区典型水稻土剖面(0—100 cm)各土层有机碳组分含量及其分布特征;并利用主成分分析获取主控因子,建立有机碳组分回归预测模型。结果表明:水稻土活性碳、慢性碳和惰性碳含量随剖面深度增加而降低,上层土壤(0—40 cm)有机碳组分含量下降速度明显快于下层土壤(40—100 cm);水稻土活性碳构成比例不超过5.3%,惰性碳构成比例大于活性碳与慢性碳比例之和,达到60%以上,水稻土有机碳总量变异主要取决于慢性碳和惰性碳组分变异。因此,水稻土固碳重点在于慢性和惰性组分。同时,研究还发现水稻土类型和剖面深度主要在表层对有机碳组分含量和比例构成产生显著影响,土壤有机碳量、全氮和pH是影响水稻土有机碳组分含量分异的主控因子,利用主控因子可较好预测水稻土有机碳组分含量。     

Role of interspecific competition in the coexistence ofApodemus argenteus andA. speciosus (Rodentia: Muridae)

Reciprocal-removal experiments with two replicates were conducted to test for the role of interspecific competition in the coexistence ofApodemus argenteus andA. speciosus. Population density, rate of appearance of new (unmarked) individuals, reproduction, survival rate and habitat use were monitored during pre- and removal periods. In both removal experiments, the removal ofA. argenteus had little effect onA. speciosus, while that ofA. speciosus affected several population characteristics ofA. argenteus. Namely, the removal ofA. speciosus shifted the distribution ofA. argenteus to the habitat with a denser shrub cover in one experiment. Also, the removal increased the population densities and appearance rates of new individuals ofA. argenteus in another experiment. Interspecific interactions between the two species appeared to be a one-way action fromA. speciosus toA. argenteus. In removal periods in both experiments, the rates of appearance of new individuals in each species were the highest on the grid where that species was removed. These results suggest that, though interspecific competition occurred between the two species, intraspecific competition had greater effects than interspecific competition on the abundance and habitat use ofA. argenteus andA. speciosus. This implies that the fundamental niches ofA. argenteus andA. speciosus differ potentially, which may play an important role in the coexistence of the two species.     

Analytical solutions for distributions of chemotactic bacteria

This paper reports general and specialized results on analytical solutions to the governing phenomenological equations for chemotactic redistribution and population growth of motile bacteria. It is shown that the number of bacteria cells per unit volume,b, is proportional to a certain prescribed function ofs, the concentration of the critical substrate chemotactic agent, for steady-state solutions through an arbitrary spatial region with a boundary that is impermeable to bacteria cell transport. Moreover, it is demonstrated that the steady-state solution forb ands is unique for a prescribed total number of bacteria cells in the spatial region and a generic Robin boundary condition ons. The latter solution can be approximated to desired accuracy in terms of the Poisson-Green's function associated with the spatial region. Also, as shown by example, closed-form exact steady-state solutions are obtainable for certain consumption rate functions and geometrically symmetric spatial regions. A solutional procedure is formulated for the initialvalue problem in cases for which significant population growth is present and bacteria cell redistribution due to motility and chemotactic flow proceeds slowly relative to the diffusion of the chemoattractant substrate. Finally, a remarkably simple exact analytical solution is reported for a stradily propagating plane-wave which features motility, chemotactic motion and bacteria population growth regulated by substrate diffusion.     

Metabolic rates during rest and activity in differently tracheated spiders (Arachnida,Araneae):<Emphasis Type="Italic"> Pardosa lugubris</Emphasis> (Lycosidae) and<Emphasis Type="Italic"> Marpissa muscosa</Emphasis> (Salticidae)

With flow-through respirometry under video tracking, the CO₂ release of adult male and female Pardosa lugubris (wolf spider) and Marpissa muscosa (jumping spider) was measured during rest and activity. Activity metabolism was measured in phases in which the animals were spontaneously active and during forced exercise. Standard metabolic rates (V_CO2/t) were 1.43 nmol s^–1 g^–1 in M. muscosa and 1.7–1.8 nmol s^–1 g^–1 in P. lugubris. Egg production caused higher resting rates in females compared with the males in P. lugubris. Maximum mass-specific CO₂ release, the additional amount of CO₂ released after activity and the factorial aerobic scope were higher in M. muscosa. Additionally, half-time recovery and the lag between end of activity and maximum CO₂ release were lower in the jumping spider. The results are consistent with the hypothesis that the well-developed tracheal system in jumping spiders increases the efficiency of the respiratory system in comparison with wolf spiders, which possess similarly developed lungs but only a simple tracheal system that is restricted to the opisthosoma.Communicated by G. Heldmaier     

Age and growth of spiny dogfish <Emphasis Type="Italic">Squalus acanthias</Emphasis> (Squalidae,Chondrichthyes) in pacific waters off the Kuril Islands

On the basis of materials collected from catches of drift salmon nets in Pacific waters off the Kuril Islands from 2005 to 2006, the age and rate of growth of spiny dogfish Squalus acanthias are considered. Individuals with a length of 67–123 cm and weight of 1140–5970 g aged 10–26 years were represented in catches. In almost all age classes, the length of males was greater and the weight smaller than in females. The lifespan of females is slightly higher as compared to males-26 and 25 years, respectively. The values of K coefficient of the Bertallanffi equation of growth in males and females comprised 0.10 and 0.05 and the calculated values of the asymptotic body length comprised 116.3 cm and 147.2 cm. A relationship was found between the age of spiny dogfish and the spine size: its length (r _s = 0.693), base width (r _s = 0.815), and base length (r _s = 0.823).