CYTOGEOGRAPHIC STUDIES ON NORTH AMERICAN ASTERS. I. RANGE SURVEYS OF VIRGULUS ADNATUS,V. CONCOLOR,V. GEORGIANUS,V. GRANDIFLORUS,V. NOVAE-ANGLIAE,V. OBLONGIFOLIUS,V. PATENS,AND V. WALTERI

Chromosome number determinations from 118 populations of eight species of the aster genus Virgulus are reported for the first time. Based on these counts and literature reports the geographic distributions of diploids and tetraploids in V. concolor, V. novae-angliae, V. oblongifolius, and V. patens have been determined. In the first three species, diploids were widely distributed, while tetraploids were more restricted. In V. patens, diploids were restricted to the southwestern portion of the species’ range, while tetraploids were found throughout the range. Both V. adnatus and V. walteri were found only at the tetraploid level throughout their ranges. Two other species with restricted distributions were consistently found to be high level polyploids: V. georgianus with 2n = 50, V. grandiflorus with 2n = 60. The following new combinations are listed: Virgulus georgianus (Alexander ex Small) Semple; Virgulus subsect. Brachyphylli (Torr. & Gray) Semple; and Virgulus sect. Polyliguli (Semple & Brouillet) Semple.     

Callus induction from protoplasts of V. unguiculata,V. sublobata and V. mungo

Summary Protoplasts were isolated from hypocotyl of V. mungo (L.) Hepper or hypocotyl-derived callus of V. sublobata (Phaseolus sublobata Roxb.) and V. unguiculata (L.) Walp (syn. V. sinensis (L.) Saviex Hassk) using an enzyme solution comprising Cellulase 2.5%, Macerozyme, Hemicellulase and Driselase each at a 0.5% level in 0.5 M sorbitol. Isolated protoplasts were cultured in Murashige and Skoog's (1962) basal liquid medium supplemented with BA, NAA, 2,4-D (1 mg/l each) and sucrose (14%). After four weeks, protoplast colonies were transferred to the same medium with a reduced level of sucrose (7%). Colonies proliferated into actively growing calli. Further attempts to regenerate plants from such calli were not successful. However, protoclones of V. unguiculata differentiated roots on auxin/cytokinin supplemented media. Alternative methods for shoot differentiation from protoplastderived cultures were tried by the use of Agrobacterium tumefaciens shooter strains pGV 2215 or pGV 2298 or wild type strain B6S3.     

Drosophila myosin V is required for larval development and spermatid individualization

Class V myosins are multifunctional molecular motors implicated in vesicular traffic, RNA transport, and mechanochemical coupling of the actin and microtubule-based cytoskeletons. To assess the function of the single myosin V gene in Drosophila (MyoV), we have characterized both deletion and truncation alleles. Mutant animals exhibit no detectable defects during embryogenesis but are delayed in larval development; most die prior to 3rd instar. MyoV protein is widely distributed; however, there are no obvious cytological defects in mutant larval tissues where MyoV was normally highly expressed. Of the few adult MyoV mutant escapers, females were fertile but males were not. We examined the expression of MyoV during spermatogenesis. MyoV was associated with membranes, microtubule, and actin structures required for spermatid maturation; MyoV was strongly associated with the sperm nuclei during the maturation of the actin-rich investment cones that package spermatids in individual membranes. In MyoV mutant escaper males, the early stages of spermatogenesis were normal; however, in the later stages, the investment cones stained weakly for actin and their registration was disrupted; no mature sperm were produced. Our results suggest that MyoV contributes to the formation of the actin-based investment cones and acts to coordinate and/or anchor these structures and other components of the individualization complex.     

Environmentally coupled hydrogen tunneling. Linking catalysis to dynamics.

Many biological C-H activation reactions exhibit nonclassical kinetic isotope effects (KIEs). These nonclassical KIEs are too large (kH/kD > 7) and/or exhibit unusual temperature dependence such that the Arrhenius prefactor KIEs (AH/AD) fall outside of the semiclassical range near unity. The focus of this minireview is to discuss such KIEs within the context of the environmentally coupled hydrogen tunneling model. Full tunneling models of hydrogen transfer assume that protein or solvent fluctuations generate a reactive configuration along the classical, heavy-atom coordinate, from which the hydrogen transfers via nuclear tunneling. Environmentally coupled tunneling also invokes an environmental vibration (gating) that modulates the tunneling barrier, leading to a temperature-dependent KIE. These properties directly link enzyme fluctuations to the reaction coordinate for hydrogen transfer, making a quantum view of hydrogen transfer necessarily a dynamic view of catalysis. The environmentally coupled hydrogen tunneling model leads to a range of magnitudes of KIEs, which reflect the tunneling barrier, and a range of AH/AD values, which reflect the extent to which gating modulates hydrogen transfer. Gating is the primary determinant of the temperature dependence of the KIE within this model, providing insight into the importance of this motion in modulating the reaction coordinate. The potential use of variable temperature KIEs as a direct probe of coupling between environmental dynamics and the reaction coordinate is described. The evolution from application of a tunneling correction to a full tunneling model in enzymatic H transfer reactions is discussed in the context of a thermophilic alcohol dehydrogenase and soybean lipoxygenase-1.     

Vibrational analysis of nucleic acids. V. Force field and conformation-dependent modes of the phosphodiester backbone modeled by diethyl phosphate.

A generalized valence force field is derived for the diethyl phosphate anion [(CH3CH2O)2PO2-] and its deuterium [(CH3CD2O)2PO2-, (CD3CH2O)2PO2- and (CD3CD2O)2PO2-] and carbon-13 [(CH3 13CH2O)2PO2-] derivatives in the stable trans-gauche-gauche-trans conformation. Normal coordinate analysis of the trans-gauche-gauche-trans conformer, which serves as a structural analog of the nucleic acid phosphodiester group, is based on comprehensive infrared and Raman spectroscopic data and vibrational assignments obtained for the diethyl phosphate anion. The generalized valence force field is in good agreement with the scaled ab initio force field of diethyl phosphate and represents significant improvement over earlier modeling of the phosphodiester moiety with dimethyl phosphate. The conformational dependence of skeletal C-C-O-P(O2-)-O-C-C stretching vibrations is also explored. Starting with the trans-gauche-gauche-trans conformation, the frequency dependence of skeletal stretching modes has been obtained by stepwise rotation of the torsion angles of the P-O and C-O bonds corresponding to nucleic acid torsions alpha (P-O5'), beta (O5'-C5'), epsilon (C3'-O3'), and zeta (O3'-P). Both symmetric and antisymmetric phosphoester stretching modes are highly sensitive to P-O and C-O torsions, whereas symmetric and antisymmetric phosphodioxy (PO2-) stretching modes are less sensitive. The present results provide an improved structural basis for understanding previously developed empirical correlations between vibrational marker bands and nucleic acid backbone conformation.     

V. Ya. Pyatigorskii

Translated from Neirofiziologiya, Vol. 24, No. 6, p. 756, November–December, 1992.     

CHROMOSOME NUMBERS IN COMPOSITAE V. ASTEREAE II.

Reports of 100 new chromosome counts are made for the tribe Astereae of Compositae, mostly based on determinations of meiotic material, including first counts for 9 genera and 53 species. Counts are now available for 58 of the approximately 100–120 genera and 431 of the approximately 2000 species in the tribe. Comparisons are made between chromosome number and habit and also between chromosome number and geographical distribution. Species and genera with a basic number of x = 9 are the most abundant. Within different phyletic lines x = 9 is also the most abundant number. On the other hand, many species with x = 4 and 5, belonging to a number of small, largely annual genera, are concentrated in southwestern North America. The low chromosome number in these plants is probably correlated with the dry habitat they occupy, and is most likely a specialized condition.     

L'azione dei raggi U.V. sul Grano

Summary

In order to study a side of the influence of ultra-violet light on plants, the A. has harvested, 10 days after fertilisation, 1040 plants of Triticum vulgare Vill. and made many groups of them; then he sheared differently the ears and screened them partially from light so as to obtain, from the same subject, treated and untreated grains. Such ears he treated for different times of exposure with the light of a quarzlamp giving almost only ultra-violet rays. For the present, are here reported only results concerning the influence of ultra-violet light upon both germinating energy and power:

• ultra-violet light stimulates the germinating power of grains, born from subjects treated no longer than 240 hours at a distance of 1 m from the lamp; longer treatments abate germinating power;

• ultra-violet light stimulates, the germinating energy of grains born from subjects treated no longer than 120 hours; treatments during 120–240 hours don't notably modify it; treatments of over 240 hours reduce it very much;

• according to the conditions in which this work has been done, a 10 days-irradiation seems to be, under every point of view, for the best. A 71/2 — days irradiation seems to be insufficient, a 121/2 — days one excessive, and hence prejudicial;

• glumes are strong screening-organ for ultra-violet light;

• ultra-violet light gives late appearing effects.

Since great difficulties usually occur whenever tests such as the present one are undertaken, the A. proposes some leading ways to previously settle the U.V.-rays dosimetry fit for every plant, in order to avoid wast of time and to get data of general value.     

Phycocyanin synthesis and degradation in the blue-green bacterium Anacystis nidulans.

Cellular content and rates of synthesis of the apoprotein subunits of phycocyanin in Anacystis nidulans cultures undergoing, and recovering from, nitrate starvation were measured by sodium dodecyl sulfate-polyacrylamide gel electrophoresis of total and immunoprecipitable soluble proteins. Results indicated that (i) nitrate starvation provokes coordinate degradation of apoprotein subunits: (ii) de novo synthesis of these subunits is selectively depressed during starvation; (iii) nitrate restoration provokes coordinate increases in the rates of synthesis of these subunits, although maximal rates are not achieved for 6 to 10 h after readdition of nitrate; and (iv) illumination affects both relative and absolute rates of apoprotein formation.     

THE RHEOLOGY OF THE BLOOD. V

A study has been made of those proteins which might offer exceptions to the law that the fluidity of a protein solution is a linear function of the volume concentration; viz., egg albumin, serum albumin, pseudoglobulin, euglobulin, gelatin, and sodium caseinogenate. Solutions of egg albumin below 20 per cent by weight obey the above law but somewhat below 30 per cent the fluidities begin to be too high, presumably due to the contribution to the fluidity made by the deformation of the particles as they come into contact, as the fluidity approaches zero. The fluidity of serum albumin solutions shows a similar behavior, being exceptional above 15 per cent in weight. Pseudoglobulin and euglobulin give fluidity-concentration curves (Fig. 4) which are linear up to about 2.5 per cent each in a total range of 20 and 14 per cent respectively. From this singular point both compounds show a second range which is linear. Pseudoglobulin is the only substance whose solutions seem to show a third linear range. We have also used the data of Chick and Martin for sodium caseinogenate and found evidence for two linear régimes. It is desirable at this time to call attention to the measurements of the flow of glycogen solutions by Botazzi and d''Errico (14) which in Fluidity and See PDF for Structure plasticity, page 207, are expressed in rhes. The data show two linear fluidity curves of different slopes. In this case it was definitely known that the data for each curve were measured with different viscometers which suggested the possibility of an error in viscometry entering in to confuse the issue. We have no suspicions as to the reliability of the data studied in this paper; we only wish to caution the readers that our hypotheses based on these data must be regarded with due reserve until confirmed. We have found a formula (11) based on the supposed linear relation between logarithmic fluidities and concentration which is convenient to use within the range, but close examination reveals that it does not reproduce the data for the higher concentrations at 25° nor does it permit extrapolation to pure water It is not realistic enough because it does not contemplate any change of régime in going from viscous to non-Newtonian or plastic flow. The formula does not apply to any other of the proteins studied in this paper nor to the great majority of proteins already reported as following the linear law. These are serious objections. We have therefore offered as an alternative a simple formula (24) according to which the fluidities are additive in the viscous régime. When the emulsoid particles approach close packing, they are deformed and this deformation contributes to the flow and the fluidity volume concentration curve is again linear. In fact, there may be one or more additional changes of régime.     

Nest thermoregulation in Vespa simillima, V.tropica and V.analis

Abstract. 1. Nest thermoregulation follows a similar pattern in Vespa simillima Smith and V. tropica L. There is a gradual decline in the daily fluctuations of nest temperature to a constant steady state which is maintained during the production of the first sexuals, followed by a sudden loss of stability at the end of the colony cycle.
2. The larvae are not major producers of heat, as they are unable to raise their body temperature by more than 1–2°C above ambient. However, they act as heat reservoirs and providers of food in the form of larval secretions. This feeding may allow workers to raise their body temperature during non-foraging periods.
3. The adults are capable of raising their body temperature many degrees above ambient and the presence of even one adult, in this case a V.analis F. mother queen, was able to raise the nest temperature.
4. Supplementary carbohydrate food promotes thermogenesis and enhances colony development.     

Monte carlo simulations of protein folding. II. Application to protein A,ROP, and crambin

The hierarchy of lattice Monte Carlo models described in the accompanying paper (Kolinski, A., Skolnick, J. Monte Carlo simulations of protein folding. I. Lattice model and interaction scheme. Proteins 18:338–352, 1994) is applied to the simulation of protein folding and the prediction of 3-dimensional structure. Using sequence information alone, three proteins have been successfully folded: the B domain of staphylococcal protein A, a 120 residue, monomeric version of ROP dimer, and crambin. Starting from a random expanded conformation, the model proteins fold along relatively well-defined folding pathways. These involve a collection of early intermediates, which are followed by the final (and rate-determining) transition from compact intermediates closely resembling the molten globule state to the native-like state. The predicted structures are rather unique, with native-like packing of the side chains. The accuracy of the predicted native conformations is better than those obtained in previous folding simulations. The best (but by no means atypical) folds of protein A have a coordinate rms of 2.25 Å from the native Cα trace, and the best coordinate rms from crambin is 3.18 Å. For ROP monomer, the lowest coordinate rms from equivalent Cαs of ROP dimer is 3.65 Å. Thus, for two simple helical proteins and a small α/β protein, the ability to predict protein structure from sequence has been demonstrated. © 1994 John Wiley & Sons, Inc.     

Studies on plasmid replication. V Replicative intermediates.

A procedure has been developed for the study of rapidly labeled intermediates in plasmid replication in normally growing bacteria. Pulse-labeled cells are enzymatically lysed on top of a neutral sucrose gradient and centrifuged so that the chromosomal DNA forms a pellet and the plasmids (and other smaller DNA molecules) form bands in the gradient. Analysis of penicillinase plasmid replication in Staphylococcus aureus has revealed that although pulse-labeled intermediates sediment faster than the 60 S circular duplex monomeric plasmid molecules, they do not have stable superhelical structure. The conversion of partially polymerized molecules, having a sedimentation coefficient of about 58 S, to fully polymerized terminal forms appears to involve a progressive change in sedimentation rate from 58 S to 67 S. Conversion of the presumably dimeric terminal forms to mature closed circular monomers is a slow and rate-limiting multi-step process (taking some 3 to 4 min at 37 °C).     

Myosin V attachment to cargo requires the tight association of two functional subdomains

The myosin V carboxyl-terminal globular tail domain is essential for the attachment of myosin V to all known cargoes. Previously, the globular tail was viewed as a single, functional entity. Here, we show that the globular tail of the yeast myosin Va homologue, Myo2p, contains two structural subdomains that have distinct functions, namely, vacuole-specific and secretory vesicle-specific movement. Biochemical and genetic analyses demonstrate that subdomain I tightly associates with subdomain II, and that the interaction does not require additional proteins. Importantly, although neither subdomain alone is functional, simultaneous expression of the separate subdomains produces a functional complex in vivo. Our results suggest a model whereby intramolecular interactions between the globular tail subdomains help to coordinate the transport of multiple distinct cargoes by myosin V.     

Tissue culture studies. V. Analogues for nicotinic acid

The use of acetyl-3-pyridine and pyridine-3-sulfonic acid as analogues for nicotinic acid has been tested with tissue cultures of embryonic chick heart. Both roller tube and Carrel flask cultures were employed. Cell migration, appearance of the cells, and the uptake of tracer P³² were used as criteria for the action of the analogues. Migration of the cells could be inhibited by both compounds, but at different levels. Both produced abnormal types of cells, but not the same type of abnormality. Uptake of P³² was inhibited by both compounds. Addition of nicotinic acid failed to reverse the effects of the analogues at the concentrations used.     

The effect of using different coordinate systems on in-vivo hip angles can be estimated from computed tomography images

Measurements of hip kinematics inherently depend on the coordinate system in which they are derived, yet the effect of the coordinate system definition on calculations of hip angles is not well-understood. Herein, hip angles calculated during dynamic activities were compared using coordinate systems described in the literature. In-vivo kinematic data of 24 participants (13 males) were analyzed during gait and the anterior impingement test using dual fluoroscopy and model-based tracking. Two coordinate systems for the pelvis (anterior pelvic plane, International Society of Biomechanics [ISB]) and three coordinate systems for the femur (table top plane with two definitions of the superior-inferior axis, ISB) were evaluated. Bony landmarks visible on computed tomography (CT) images were identified to establish each coordinate system and used as the basis to calculate differences in hip angles between coordinate system pairs. In the analysis during gait, the maximum differences derived from various coordinate system definitions were 6.7° ± 5.5° for flexion, 7.7° ± 2.1° for rotation, and 5.5° ± 0.7° for adduction. For the anterior impingement test, the differences were 8.1° ± 5.9°, 7.1° ± 1.2°, and 5.3° ± 0.7°, respectively. Landmark-based analysis using CT images could estimate these dynamic differences with errors less than 1.0°. Our results indicate that hip angles can be accurately transformed to angles calculated in different coordinate systems by accounting for the inherent bony anatomy. This information may aid in the interpretation of results across biomechanical studies of the hip.     

Sesquiterpene lactones from two newly-described species of Vernonia: V. jonesii and V. pooleae

Two novel, non-glaucofide, germacrolide sesquiterpene lactones, 8α-methacryloyloxycostunolide-1(10),4(5)-diepoxide and 1-oxo-10α-OH-8α-methacryloyloxycostunolide (not fully characterized), were isolated from Vernonia jonesii and the previously described glaucolide B was identified from V. pooleae. This is one of the few reports of non-glaucolide type germacrolides in a New World species of Vernonia, although members of this class of sesquiterpene lactones are common constituents of Old World species of the genus. The chemical evidence supports the suggestion that V. jonesii may be part of a relictual, isolated group of the New World Vernonia, closely related to some of the Old World taxa.     

Hybridization of cultivated Vitis vinifera with wild V. californica and V. girdiana in California

Hybridization of introduced domesticates and closely related natives is well documented in annual crops. The widespread introduction of the domesticated grapevine, Vitis vinifera, into California where it overlaps with two native congenerics, with which it is interfertile, provides opportunity to investigate hybridization between woody perennials. Although geographically widespread, the introduction over the past two centuries has been limited to a few elite clonal cultivars, providing a unique opportunity to study the effects of hybridization on the native species. The amount of hybridization with V. vinifera and the genetic diversity of wild‐growing Vitis californica and Vitis girdiana were examined using nineteen microsatellite markers. STRUCTURE analysis was used to define hybrid and introgressed individuals and to analyze genetic structure of the native species. FAMOZ software was used to identify which V. vinifera cultivars served as parents of F₁ hybrids. The three species were clearly distinguished by STRUCTURE analysis. Thirty percent of 119 V. californica vines were hybrids. The domesticated parent was identified for 16 F₁ hybrid vines; the original California cultivar, ‘Mission’, was the parent of eight. Backcrosses were also found, showing introgression into subsequent generations. Similar results were obtained for a small sample of V. girdiana. Removing hybrids greatly reduced the genetic variation of the presumed pure species, among which there was essentially no genetic structure. Limited genetic variability indicates the California natives may be threatened by genetic erosion. The discovery of F₁ hybrids of ‘Mission’, a cultivar not grown in the areas for ~100 years, suggests long generation times for wild vines that, often, grow into expansive liana and propagate by layering, all factors that limit recruitment in populations already disjunct by habitat lose. Hermaphroditic flowers and fruit that is more attractive to birds may favor the production of backcross seed and establishment of introgressed individuals.     

V. Beitr?ge zur Biologie papuanischer V?gel

Ohne ZusammenfassungOrnithologische Ergebnisse der Expedition Stein 1931–1932.I. Die Vögel von Waigeu; II. Die Vögel von Numfor; III. Die Vögel von Japen (= Jobi), in: Novit. Zoologicae 38, 1932, p. 127 bis 247. — IV. Die Vögel des Weyland-Gebirges und seines Vorlandes, in: Mitt. Zoolog. Mus. Berlin Bd. 21.     

A mechanistic model for morphogenesis and regeneration of limbs and imaginal discs.

When an amphibian limb, cockroach leg or Drosophila imaginal disc is subjected to a surgical operation, it is capable of regenerating or duplicating certain parts. Although the structure of the regenerated tissue varies depending on the location and mass of the amputated or transplanted part, it can be predicted from a set of formal rules, called the polar coordinate model [French et al., (1976) Science 193, 969-983; Bryant et al., (1981) Science 212, 993-1002]. In the polar coordinate model, it is assumed (and experimentally proven) that the juxtaposition of normally non-adjacent cells stimulates cell proliferation locally, which implies that the underlying mechanism which gives positional values to each cell, is also responsible for the control of cell growth. Because locally activated proliferation alters the shape and size of the developmental field, the question of how to control the cell growth is the central problem in the regeneration of the limbs and imaginal discs. In this paper, I propose a possible underlying mechanism for the 'polar coordinate rules', and show how this mechanistic model explains the experimental results using computer simulation. The proposed mechanism is an extension of Turing's model (1952). In addition to the reaction-diffusion of the molecules, cell proliferation is taken into consideration. With appropriate initial conditions, the computer simulation shows that a small mass of cells grows up to form a mature limb, and that the mature limb is able to respond to surgical operations as predicted by the polar coordinate model.