Enzyme Changes in Relation to Cell Growth in Excised Root Tissues1

Serial sections 10 mm. in length taken from the tip towardsthe base of the bean root have been cultured on 2 per cent,sucrose. At various time-intervals, length, invertase, phosphatase,and protein content of the sections have been determined. Alterationsin the enzyme complement of the sections have been related togrowth and protein content. The relation of changes occurringin excised fragments to those in the intact root have been discussed.     

Fat and body condition in migrating Redwings Turdus iliacus

During the night of 29–30 October 1995, over 600 Redwings Turdus iliacus died as a result of flying into the lighthouse at Bardsey, Gwynedd, North Wales. These migrating birds were used to investigate fat levels in relation to age, sex, biometrics and pectoral muscle mass. Wing length was the best single linear measure of size and mean wing length of males was 2.5 mm greater than that of females. Body mass of the casualties declined during the night and the mean body mass of birds arriving towards the end of the night was 1.5 g lower than that of the first arrivals. Fat deposits at different body sites were significantly correlated with each other and with body mass, and, by extrapolation, the mass of intra-abdominal fat remaining would be significant when other fat deposits have been depleted. Fat in the tracheal pit (the claviculo-coracoid fat body) demonstrated the best correlation with body mass and was linearly correlated with visual fat scores. Fat was also present in the pectoral muscle but did not make a significant contribution to overall body mass. Two-thirds of the variation in body mass was accounted for by wing length, the mass of claviculo-coracoid fat and the lean-dry mass of pectoral muscle. Claviculo-coracoid fat and lean pectoral-muscle mass contributed independently to overall body mass. These data support the view that increase in fat in relation to migration is accompanied by an increase in protein or lean muscle mass, but suggest that these are controlled independently.     

Ulteriori Osservazioni Sulla Variabilità Del Legno Secondario in Prunus Persica Stokes

Abstract

Further observations on the variability of the secondary wood of PRUNUS PERSICA Stokes. — The length of both fibres and vessel members and the age of cambium in the trunk of a wild specimen of Prunus persica are positively correlated; no relation exists between the length of the above mentioned elements and the width of growth layers.

The relation between the intrasive growth of fibres and either age of cambium or width of growth layers has been also calculated but no significant relation has been attained.

The results have been compared with those obtained in the previous study of a trunk of a grafted Prunus persica, which are very different and quite peculiar mainly as to a decrease in length of fibres and vessel members with aging of cambium. The growing practice to which the tree may have been subjected is regarded as the possible cause of this peculiarity.     

Damage to different motor units from active lengthening of the medial gastrocnemius muscle of the cat.

Slow-twitch motor units in the medial gastrocnemius muscle of the anesthetized cat were found to have an average optimum length for active tension that was 0.8 +/- 0.5 (SE) mm longer than the whole muscle optimum. For fast-twitch units (time to peak < 50 ms), the average optimum was 1.3 +/- 0.3 mm shorter than the whole muscle optimum. After the muscle had been subjected to 10 stretches while maximally activated, beginning at the whole muscle optimum length, the optimum lengths of the 27 fast-twitch motor units shifted significantly further in the direction of longer muscle lengths (mean 4.3 +/- 0.3 mm) than for the eight slow-twitch units (2.1 +/- 0.4 mm). A shift in the muscle's length-tension relation was interpreted as being due to sarcomere disruption. Statistical analysis showed that a motor unit's optimum length for a contraction, relative to the whole muscle optimum, was a better indicator of the unit's susceptibility to damage from active lengthenings than was motor unit type.     

Parental influence on growth rate, smolting rate and survival in hatchery reared juvenile Atlantic salmon, Salmo salar

The proportion of potential 1-year smolts, their mean length, the mean length of potential 2-year smolts, and the mortality rate in four half-sib families of Atlantic salmon, reared under four contrasted conditions of overhead cover, is shown to be inffuenced primarily by genetic factors (89.9%, 86.1 %, 82.7% and 80.2% of total variance respectively). Variation between families in smolting rate and mortality rate is influenced by both parents, but more by the male than the female. Variation in mean length is influenced almost entirely by the female parent. These results are discussed in relation to previous findings on bimodality of size distribution and inheritance of growth and mortality characteristics in Atlantic salmon.     

Mating ecology of beluga (Delphinapterus leucas) and narwhal (Monodon monoceros) as estimated by reproductive tract metrics

Narwhal and beluga whales are important species to Arctic ecosystems, including subsistence hunting by Inuit, and little is understood about their mating ecology. Reproductive tract metrics vary across species in relation to mating strategy, and have been used to infer mating ecology. Reproductive tracts from beluga and narwhal were collected between 1997 and 2008 from five beluga stocks and two narwhal stocks across the Canadian Arctic. Tract length for males and females, relative testes mass for males, and tusk length for male narwhal were measured. We assessed variation relative to species, body size, stock, maturity, and season. Significant variation was found in testes mass across month and stock for beluga, and no significant difference between stock or date of harvest for narwhal. Beluga had significantly larger testes relative to body size than narwhal, suggesting they were more promiscuous than narwhal. A significant relationship was found between narwhal tusk length and testes mass, indicating the tusk may be important in female mate choice. No significant differences were found between narwhal and beluga reproductive tract length for males or females. The mating systems suggested for narwhal and belugas by our results mean the two species may respond differently to climate change.     

Electrical and hydrodynamical properties of polypeptides in solution. I. Poly(L-glutamic acid) in methanol-water mixtures

The electric birefringence of poly(L -glutamic acid) (PLGA) in methanol–water mixtures has been measured by the use of the rectangular pulse technique at 25°C. The permanent dipole moment, the anisotropy of electrical polarizability, and the optical anisotropy factor of PLGA in solution were obtained from the dependence of the steady-state birefringence on the electric field strength. Further, the mean length of PLGA in solution was calculated by a parameter method developed for analyzing the decay curve of electric birefringence. The permanent dipole moment per unit length obtained from these studies was 2.9₆, 2.4₈, 2.3₀, 2.6₆ D/Å in pure methanol, 10, 30, and 50 vol-% water, respectively. The increase of water content caused the decrease of the mean length and broadened the length distribution of PLGA. These results are discussed in relation to the viscosity and the electrical conductivity of PLGA solutions.     

Relation between upper airway volume and hyoid muscle length

Previous studies have suggested that the geniohyoid and sternohyoid muscles act to enlarge the upper airway. If correct, there should be an inverse relation between upper airway volume and the length of hyoid muscles. To test this, known volumes of air were injected into or removed from the isolated sealed upper airway of eight pentobarbital sodium-anesthetized cats, and the resultant changes in geniohyoid and sternohyoid length were measured using sonomicrometry. Increases in upper airway volume shortened the geniohyoid in all cats (P less than 0.001) and shortened the sternohyoid in seven of eight cats (P less than 0.01); mean geniohyoid shortening (as a % of resting length) exceeded that of the sternohyoid. Decreases in upper airway volume lengthened the geniohyoid in all cats (P less than 0.001) but caused variable changes in sternohyoid length. Extension of the neck increased the resting lengths of both the geniohyoid (P less than 0.001) and sternohyoid (P less than 0.002). Neck flexion shortened the resting length of both hyoid muscles (P less than 0.001 for both), with the geniohyoid shortening more (as a % of resting length) than the sternohyoid (P less than 0.005). Progressive flexion of the neck from 180 to 90 degrees caused progressive increases in the ratio of changes in muscle length to changes in upper airway volume during airway inflation but did not affect this relation during airway deflation.(ABSTRACT TRUNCATED AT 250 WORDS)     

Size variation and orientation of the human Y chromosome

Summary The material consists of 84 metaphase plates from 17 individuals with clearly distinguishable Y chromosomes. The plates were obtained from leucocyte cultures. In making the preparations, exactly the same procedure was employed in all cases, including among other things, air-drying and light flaming.It was found that the size of the Y chromosome is subject to interindividual variation. The size of the Y chromosome has been expressed in relation to the mean length of the other small acrocentric chromosomes. The chromosomes have been tentatively classified into the following main groups:1. Y/G = 1.8; 2. Y/G =1.5; 3. Y/G is somewhat larger than G or 1.1, and 4. Y/G equals the mean of the small acrocentric chromosomes, or Y/G = 1. In the long Y chromosome two secondary constrictions have been observed.The location of the Y chromosome has been determined as peripheral or non-peripheral. The proband material has been divided into three main groups. The first comprises the individuals with a large Y chromosome (Y/G = 1.8). The second group includes individuals showing Down's syndrome and having 47 chromosomes, and the third comprises individuals with 46 chromosomes and possessing a Y/G sized 1 to 1.5. Preferential peripheral location of the Y chromosome has not been statistically verified in any one of these groups.     

A method for estimating the proportion of sieve tubes in the phloem of higher plants

Summary A statistical method has been developed for the estimation of the proportion of phloem area occupied by sieve tube lumen which is applicable to most higher plants. By simple probability, the number of sieve tubes in a given area of phloem is equal to the number of sieve plates present in a series of transverse sections whose total thickness equals the mean sieve element length. The case of oblique sieve plates, where the plate is divided and occurs in more than one section, has also been dealt with and a solution obtained. Estimates of the proportion of phloem area occupied by sieve tubes have been made by this method in willow (Salix viminalis L.), sugar beet (Beta vulgaris L.) and a cucurbit (Ecballium elaterium L.) and the values obtained discussed in relation to estimates made previously by other methods.     

Telomere Length Dynamics in Telomerase-Positive Immortal Human Cell Populations

It has been proposed that the progressive shortening of telomeres in somatic cells eventually results in senescence. Previous experiments have demonstrated that many immortal cell lines have acquired telomerase activity leading to stabilization of telomere length. Telomere dynamics and telomerase activity were examined in the telomerase-positive immortal cell lines HeLa and 293 and subclones derived from them. A mass culture of HeLa cells had a stable mean telomere length over 60 population doublings (PD)in vitro.Subclones of this culture, however, had a range of mean telomere lengths indicating that telomeric heterogeneity exists within a population with a stable mean telomere length. Some of the subclones lacked detectable telomerase activity soon after isolation but regained it by PD 18, suggesting that at least some of the variation in telomere length can be attributed to variations in telomerase activity levels. 293 subclones also varied in telomere length and telomerase activity. Some telomerase-positive 293 subclones contained long telomeres that gradually shortened, demonstrating that factors other than telomerase also act to modulate telomere length. Fluctuations in telomere length in telomerase-positive immortalized cells may contribute to chromosomal instability and clonal evolution.     

Validity of the Force-Velocity Relation for Muscle Contraction in the Length Region, l ≤ l0

Considerable attention has been directed to the characteristic force-velocity relation discovered by A. V. Hill in the study of muscle kinematics. Models of contractile process were tested on the basis of their compatibility with the Hill equation. However, almost all the isotonic data have been restricted to one length, l₀, the maximum length with almost no resting tension; the velocities measured are those initial values when the load begins to move. The force-velocity curve extrapolates to zero velocity for isometric tension, but only for the tension at that one length. Very few efforts have been made to study the profiles of the curves throughout the range of lengths over which shortening takes place. In examining the length region, l ≤ l₀, for an isotonically contracting muscle, not only is the force-velocity relation valid for the initial reference length, l₀, but also for any other length. The analysis in this report indicates that the constants a/P₀ and b/l₀ remain fixed throughout the length change of afterloaded isotonic shortening in the Rana pipiens sartorius muscles.     

Staying in plastic containers interferes with the orientation of clock-shifted homing pigeons

Staying in plastic containers ventilated with natural air during transport and while waiting at the release site was found to affect the initial orientation of pigeons, Columba livia f. domestica, that were exposed to a 6-h clock-shift. The deflection from the mean direction of controls was significantly smaller, and the mean vector length was significantly shorter, than that of clock-shifted pigeons transported in conventional wooden cages. This effect was most pronounced when the birds stayed in plastic containers for the first and second time. Nonshifted control birds seemed to be largely unaffected by plastic containers. There was no influence on homing performance, which suggests a transient nature of the effect. Since the clock-shifted birds had access to the same orientational cues as the controls, we suggest that their sun compass was impaired by stress. We discuss general implications of this container effect, particularly in relation to some cases of olfactory deprivation where containers have been used and stress-induced side-effects cannot be excluded. Copyright 1999 The Association for the Study of Animal Behaviour.     

The membrane potentials of fibroblasts in different environments

The membrane potentials of human embryonic lung fibroblasts have been measured in different cellular environments. Sparse cells on plastic have a mean membrane potential of ?8.5 mV. As the cells progress to dense culture, the mean membrane potential rises to ?14.7 mV. The mean membrane potential of fibroblasts in human embryonic lung fragments by comparison was found to be ?16.5 mV. Sparse cells on collagen, at the same density as the sparse cells on plastic, have mean membrane potentials of ?10.8 mV. Sparse cells on plastic migrating from dense cellular areas, following a cut being made in a thick sheet of cells, have mean membrane potentials of ?5.9 mV. The significance of these results in relation to cellular environments has been discussed.     

Effect of agitation intensities on fungal morphology of submerged fermentation

Both parallel fermentations with Aspergillus awamori (CBS 115.52) and a literature study on several fungi have been carried out to determine a relation between fungal morphology and agitation intensity. The studied parameters include hyphal length, pellet size, surface structure or so-called hairy length of pellets, and dry mass per-wet-pellet volume at different specific energy dissipation rates. The literature data from different strains, different fermenters, and different cultivation conditions can be summarized to say that the main mean hyphal length is proportional to the specific energy dissipation rate according to a power function with an exponent of -0.25 +/- 0.08. Fermentations with identical inocula showed that pellet size was also a function of the specific energy dissipation rate and proportional to the specific energy dissipation rate to an exponent of -0.16 +/- 0.03. Based on the experimental observations, we propose the following mechanism of pellet damage during submerged cultivation in stirred fermenters. Interaction between mechanical forces and pellets results in the hyphal chip-off from the pellet outer zone instead of the breakup of pellets. By this mechanism, the extension of the hyphae or hair from pellets is restricted so that the size of pellets is related to the specific energy dissipation rate. Hyphae chipped off from pellets contribute free filamentous mycelia and reseed their growth. So the fraction of filamentous mycelial mass in the total biomass is related to the specific energy dissipation rate as well.To describe the surface morphology of pellets, the hyphal length in the outer zone of pellets or the so-called hairy length was measured in this study. A theoretical relation of the hairy length with the specific energy dissipation rate was derived. This relation matched the measured data well. It was found that the porosity of pellets showed an inverse relationship with the specific energy dissipation rate and that the dry biomass per-wet-pellet volume increased with the specific energy dissipation rates. This means that the tensile strength of pellets increased with the increase of specific energy dissipation rate. The assumption of a constant tensile strength, which is often used in literature, is then not valid for the derivation of the relation between pellet size and specific energy dissipation rate. The fraction of free filamentous mycelia in the total biomass appeared to be a function of the specific energy dissipation in stirred bioreactors. (c) 1997 John Wiley & Sons, Inc. Biotechnol Bioeng 55: 715-726, 1997.     

Quantitative studies on the neuron structure of the rat fascia dentata]

1. In 6 month old male rats the structure of dendrites and the distribution of spines on the apical dendrites of granular cells of the dentate gyrus were investigated by light microscopy and statistical methods. 2. The number of dendrites of the first, second and third order of granular cells increases in this sequence in a ratio of 1:2:3; the total length of the dendrites increases correspondently in a ratio of 1:4:5. 3. The mean number of origin points of dendritic branches is 10, the mean number of free dendritic endings is 12. 4. The number of spines per a 25 mum dendritic segment near to the pericaryon (dendritic segment A), in the middle of the dendrite (dendritic segment B) and in the peripheral dendritic part (dendritic segment C) as well as the distribution of spines in the whole apical dendrite was evaluated. The total mean of spines of granular cell apical dendrites of the dentate gyrus (superior respectively inferior) is 12 respectively 10 for the dendritic segment A, 18 respectively 17 for the dendritic segment B and 17 respectively 15 for the dendritic segment C calculated for a dendritic length of 25 mum. 5. The spine density in each case depends upon the distance pericaryondendritic segment and is in close relation to the adjacent layers with their specific afferents. 6. The averaged total number of spines per 1 mum of dendritic length is 0,62 spines/mum for the dentate gyrus (superior) and 0,57 spines/mum for the dentate gyrus (inferior). 7. The granular cells of the dentate gyrus (superior) have a mean dendritic length of a total of 357 mum with a total of 226 visible spines; the granular cells of the dentate gyrus (inferior) have a mean dendritic length of a total of 450 mum with a total of 258 visible spines.     

Electric and hydrodynamic properties of polypeptides in solution. IV. A new conformational change of poly(L-glutamic acid) in dimethylsulfoxide–methanol mixtures

The electric birefringence of poly(L -glutamic acid) (PLGA) in dimethylsulfoxide (DMSO)–methanol mixtures has been measured by use of the rectangular pulse technique. The length distribution curve, the mean molecular length, and the mean apparent permanent dipole moment of PLGA in solution have been obtained from the decaycurve and field strength dependence of the steady-state birefringence according to the method developed for analyzing the electric birefringence of a polydisperse system. The length distribution curve exhibits one or two peaks. The length corresponding to a high peak and the mean length of PLGA undergo an abrupt change in the vicinity of 50 to 60 vol % DMSO at 30°C. Moreover, a sharp change of the Moffitt b₀ parameter with the solvent composition is observed. These results provide evidence for the existence of a solvent-induced transition from a helical conformation (presumably α-helix) to another helical conformation with shorter length per amino acid residue. Further, the temperature dependence of the length distribution of PLGA in 50 vol % DMSO suggests the existence of a temperature-induced helix ? helix transition.     

Passage time,resilience, and structure of compartmental models

The relation between the graphical structure and two measures of stability of a compartmental model is studied. The two are resilience as measured by deviation from equilibrium throughout the history of the system and mean first passage time from a central compartment back to itself. A number of examples are studied and a theory developed for models whose graphical structure is in the form of an advanced rosette. The resilience, known to increase with complexity, is shown to increase as well with uneveness in length of food chains. The mean first passage time, on the other hand, depends only on the number of food chains and their average length.     

Maternal blood pressure and fetal ultrasonography in normal baboon pregnancies

Pregnancy in baboons is characterized by lower systolic, diastolic, and mean blood pressures than in the nonpregnant state. As pregnancy progresses, diastolic and mean pressures tend to increase whereas systolic pressure remains low. Sonographic measurements of fetal growth follow a sigmoid pattern, but their increase in relation to length of gestation approximates a straight line between 6 and 21 weeks of gestation (23 to 84% of term).