scholarly journals II. On the histology of uredo dispersa , erikss., and the "mycoplasm" hypothesis

1904 ◽  
Vol 196 (214-224) ◽  
pp. 29-46 ◽  
Keyword(s):  
Royal Society ◽  
Rust Fungus ◽  
Rust Fungi ◽  
Pure Cultures ◽  
The One ◽  
Microscopic Investigations

There are still so many and such important gaps in our knowledge of the biology of the Uredineæ, that no one will expect an apology for a serious attempt to fill any of them, and the less so in the particular case of the Rust-fungi of the Gramineæ and cereals, because, notwithstanding the numerous researches which have succeeded each other since De Bary’s classical investigations, the whole question of the origin and spread of epidemics of rust has been raised again owing to the remarkable discovery of the specialised parasitism exhibited by certain adapted races of these fungi, and to the still more remarkable assumptions published by Eriksson in what is known as the “Mycoplasm” hypothesis. I have from time to time brought before the notice of the Royal Society and elsewhere, the results of my own investigations into the biology of that particular form of Rust-fungus known as Puccinia dispersa , Erikss., more especially with reference to its peculiar parasitism on the grasses of the genus Bromus , and have treated successively of the questions of predisposition and immunity, of the relations between the host and the parasite, of the method of pure cultures of such a Uredine as the one in question, and of the effects of mineral starvation on its parasitism. In all these cases, however, the studies were chiefly experimental, dealing with the physiology of infection, and the publication of the results of the extensive and far more laborious microscopic investigations was reserved, a few remarks only being made here and there showing the directions in which these were leading from time to time.

scholarly journals Description of a new barometer, recently fixed up in the apart­ments of the Royal Society; with remarks on the mode hitherto pursued at various periods, and an account of that which is now adopted, for correcting the observed height of the mercury in the society’s barometer

1843 ◽  
Vol 4 ◽  
pp. 1-3
Keyword(s):  
Royal Society ◽  
The Other ◽  
Chemical Effect ◽  
The Absolute ◽  
The One ◽  
And Control ◽  
Usual Scale

The barometer, here alluded to, may in some measure be consi­dered as two separate and independent barometers, inasmuch as it is formed of two distinct tubes dipping into one and the same cistern of mercury. One of these tubes is made of flint glass, and the other of crown glass, with a view to ascertain whether, at the end of any given period, the one may have had any greater chemical effect on the mercury than the other, and thus affected the results. A brass rod, to which the scale is attached, passes through the framework, between the two tubes, and is thus common to both : one end of which is furnished with a fine agate point, which, by means of a rack and pinion moving the whole rod, may be brought just to touch the surface of the mercury in the cistern, the slightest contact with which is immediately discernible; and the other end of which bears the usual scale of inches, tenths, &c.; and there is a separate vernier for each tube. A small thermometer, the bulb of which dips into the mercury in the cistern, is inserted at the bottom : and an eye­piece is also there fixed, so that the agate point can be viewed with more distinctness and accuracy. The whole instrument is made to turn round in azimuth, in order to verify the perpendicularity of the tubes and the scale. It is evident that there are many advantages attending this mode of construction, which are not to be found in the barometers as usu­ally formed for general use in this country. The absolute heights are more correctly and more satisfactorily determined ; and the per­manency of true action is more effectually noticed and secured. For, every part is under the inspection and control of the observer; and any derangement or imperfection in either of the tubes is imme­diately detected on comparison with the other. And, considering the care that has been taken in filling the tubes, and setting off the scale, it may justly be considered as a standard barometer . The pre­sent volume of the Philosophical Transactions will contain the first register of the observations that have been made with this instru­ment.

scholarly journals XXII.—Observations on the Phonograph

1897 ◽  
Vol 38 (4) ◽  
pp. 765-785
Author(s):  
John G. M'Kendrick
Keyword(s):  
Royal Society ◽  
Good Deal ◽  
American Model ◽  
Spiral Line ◽  
The One ◽  
Spiral Grooves ◽  
Special Meeting

1. Since I had the honour of showing the phonograph to the Royal Society of Edinburgh, at a special meeting in November 1894, the instrument has occupied a good deal of my time and attention, and I now venture to give the general results of the investigation.2. The instrument chiefly studied has been the machine used in this country known as the “Commercial Phonograph.” Any records taken by myself have been obtained with the ordinary apparatus forming part of the “commercial” speaker arm, but I have always reproduced these with the aid of the so-called “musical” arm. The commercial machine, or, to give it a better name, the English model, is so geared that the wax cylinder, inch (197 mm.) in circumference, makes two revolutions in one second, while the spiral grooves described on the cylinder are inch (⅛ mm.) apart. A spiral line about 136 yards in length may be described on the cylinder, and the recording or reproducing point travels over this distance in about six minutes.3. I have also used the American model, which resembles in all essential particulars the one just described, except that the grooves on the cylinder are inch (¼ mm.) instead of .

scholarly journals On some circumstances relating to the economy of bees

1833 ◽  
Vol 2 ◽  
pp. 346-347
Keyword(s):  
Royal Society ◽  
The State ◽  
The Other ◽  
Compact Mass ◽  
Whole Number ◽  
Permanent Settlement ◽  
The One ◽  
Hollow Tree ◽  
As If

The author had already stated, in a former communication to the Royal Society, his having noticed that for several days previous to the settling of a swarm of bees in the cavity of a hollow tree adapted to their reception, a considerable number of these insects were incessantly employed in examining the state of the tree, and particularly of every dead knot above the cavity which appeared likely to admit water. He has since had an opportunity of observing that the bees who performed this task of inspection, instead of being the same individuals as he had formerly supposed, were in fact a continual succession of different bees; the whole number in the course of three days being such as to warrant the inference that not a single labouring bee ever emigrates in a swarm without having seen its proposed future habitation. He finds that the same applies not only to the place of permanent settlement, but also to that where the bees rest temporarily, soon after swarming, in order to collect their numbers. The swarms, which were the subjects of Mr. Knight’s experiments, showed a remarkable disposition to unite under the same queen. On one occasion a swarm, which had arisen from one of his hives, settled upon a bush at a distance of about twenty-five yards; but instead of collecting together into a compact mass, as they usually do, they remained thinly dispersed for nearly half an hour; after which, as if tired of waiting, they singly, one after the other, and not in obedience to any signal, arose and returned home. The next morning a swarm issued from a neighbouring hive, and proceeded to the same bush upon which the other bees had settled on the preceding day; collecting themselves into a mass, as they usually do when their queen is present. In a few minutes afterwards a very large assemblage of bees rushed from the hive from which the former swarm had issued, and proceeded directly to the one which had just settled, and instantly united with them. The author is led from these and other facts to conclude that such unions of swarms are generally, if not always, the result of previous concert and arrangement.

scholarly journals Further note on the influence of a magnetic field of radiation frequency

1897 ◽  
Vol 61 (369-377) ◽  
pp. 413-415
Keyword(s):  
Magnetic Field ◽  
Royal Society ◽  
Ruled Surface ◽  
Radius Of Curvature ◽  
Radiation Frequency ◽  
The Subject ◽  
The One

Referring to a former communication of mine, on the subject of Zeeman’s discovery, printed on page 513 of the ‘Proceedings of the Royal Society ’for February 11 this year, vol. 60, No. 367, I wish to add an observation to those previously recorded, as I have recently acquired a concave Rowland grating (3½ X 1½-inch ruled surface, 14,438 lines to inch, 10 feet radius of curvature, being the one used by Mr. George Higgs), of which the spectra of the first and third orders on one side are very satisfactory.

XXIV.—On the Temperature Coefficient of Concentration Cells, in which the same salt is dissolved in two different solvents

1912 ◽  
Vol 31 ◽  
pp. 375-396
Author(s):  
A. P. Laurie
Keyword(s):  
Temperature Coefficient ◽  
Potassium Iodide ◽  
Royal Society ◽  
Platinum Electrode ◽  
The Other ◽  
Absolute Alcohol ◽  
Concentration Cell ◽  
New Type ◽  
The One ◽  
Concentration Cells

In a paper read before the Royal Society of Edinburgh (Proc. Roy. Soc. Edin., xxviii., part v., p. 382 (1908); Zeit. phys. Chem., lxiv. 5) I described a new type of concentration cell, in which the one platinum electrode was surrounded by a solution of ·025 molecules of KI containing ·001 molecules of iodine dissolved in absolute alcohol, and the other electrode was surrounded by ·025 molecules of KI and ·001 molecules of iodine, dissolved in water. This cell developed a considerable E.M.F. of ·198 volts at 25° C. in the direction which would transfer the iodine from water to alcohol and potassium iodide from alcohol to water.

scholarly journals VII.—On the Motion of a Heavy Body along the Circumference of a Circle

1865 ◽  
Vol 24 (1) ◽  
pp. 59-71
Author(s):  
Edward Sang
Keyword(s):  
Royal Society ◽  
Elliptic Functions ◽  
The Other ◽  
Philosophical Magazine ◽  
Circular Arc ◽  
Heavy Body ◽  
Great Ease ◽  
Fourth Volume ◽  
The Common ◽  
The One

In the year 1861 I laid before the Royal Society of Edinburgh a theorem concerning the time of descent in a circular arc, by help of which that time can be computed with great ease and rapidity. A concise statement of it is printed in the fourth volume of the Society's Proceedings at page 419.The theorem in question was arrived at by the comparison of two formulæ, the one being the common series and the other an expression given in the “Edinburgh Philosophical Magazine” for November 1828, by a writer under the signature J. W. L. Each of these series is reached by a long train of transformations, developments, and integrations, which require great familiarity with the most advanced branches of the infinitesimal calculus; yet the theorem which results from their comparison has an aspect of extreme simplicity, and seems as if surely it might be attained to by a much shorter and less rugged road. For that reason I did not, at the time, give an account of the manner in which it was arrived at, intending to seek out a better proof. On comparing it with what is known in the theory of elliptic functions, its resemblance to the beautiful theorem of Halle became obvious; but then the coefficients in Halle's formulæ are necessarily less than unit, whereas for this theorem they are required to be greater than unit.

scholarly journals An Investigation into the Involvement of Defense Signaling Pathways in Components of the Nonhost Resistance of Arabidopsis thaliana to Rust Fungi Also Reveals a Model System for Studying Rust Fungal Compatibility

2003 ◽  
Vol 16 (5) ◽  
pp. 398-404 ◽  
Author(s):  
Denny G. Mellersh ◽  
Michèle C. Heath
Keyword(s):  
Arabidopsis Thaliana ◽  
Rust Fungus ◽  
Fungal Growth ◽  
Rust Fungi ◽  
Nonhost Resistance ◽  
Wild Type ◽  
Pr Genes ◽  
Hypersensitive Cell Death ◽  
Defense Signaling ◽  
Infection Hypha

Seventeen accessions of Arabidopsis thaliana inoculated with the cowpea rust fungus Uromyces vignae exhibited a variety of expressions of nonhost resistance, although infection hypha growth typically ceased before the formation of the first haustorium, except in Ws-0. Compared with wild-type plants, there was no increased fungal growth in ndr1 or eds1 mutants defective in two of the signal cascades regulated by the major class of Arabidopsis host resistance genes. However, in the Col-0 background, infection hyphae of U. vignae and two other rust fungi were longer in sid2 mutants defective in an enzyme that synthesizes salicylic acid (SA), in npr1 mutants deficient in a regulator of the expression of SA-dependent pathogenesis related (PR) genes, and in NahG plants containing a bacterial salicylate hydroxylase. Infection hyphae of U. vignae and U. appendiculatus but not of Puccinia helianthi were also longer in jar1 mutants, which are defective in the jasmonic acid defense signaling pathway. Nevertheless, haustorium formation increased only for the Uromyces spp. and only in sid2 mutants or NahG plants. Rather than the hypersensitive cell death that usually accompanies haustorium formation in nonhost plants, Arabidopsis typically encased haustoria in calloselike material. Growing fungal colonies of both Uromyces spp., indicative of a successful biotrophic relationship between plant and fungus, formed in NahG plants, but only U. vignae formed growing colonies in the sid2 mutants and cycloheximide-treated wild-type plants. Growing colonies did not develop in NahG tobacco or tomato plants. These data suggest that nonhost resistance of Arabidopsis to rust fungi primarily involves the restriction of infection hypha growth as a result of defense gene expression. However, there is a subsequent involvement of SA but not SA-dependent PR genes in preventing the Uromyces spp. from forming the first haustorium and establishing a sufficient biotrophic relationship to support further fungal growth. The U. vignae-Arabidopsis combination could allow the application of the powerful genetic capabilities of this model plant to the study of compatibility as well as nonhost resistance to rust fungi.

scholarly journals Leaf Cuticle Can Contribute to Non-Host Resistance to Poplar Leaf Rust

Forests ◽  
2019 ◽  
Vol 10 (10) ◽  
pp. 870 ◽  
Author(s):  
Yu ◽  
Shen ◽  
Newcombe ◽  
Fan ◽  
Chen
Keyword(s):  
Host Resistance ◽  
Populus Deltoides ◽  
Rust Fungus ◽  
Trimethylsilyl Ether ◽  
Populus Tomentosa ◽  
Rust Fungi ◽  
Mesophyll Cells ◽  
Defense Compounds ◽  
Leaf Cuticle ◽  
Poplar Leaf

The plant leaf cuticle is a chemically complex but largely waxy outer shell that limits water loss and also prevents some pathogens from gaining access to internal mesophyll. Rust fungi are obligate parasites, and most bypass the cuticle by thigmotropically locating stomata, growing through the stomatal openings, and then parasitizing mesophyll cells with haustoria. It is thought that even non-hosts of a given rust fungus do not resist until their mesophyll cells are contacted in this way. In other words, it is thought that the cuticle plays no role in non-host resistance. Here, we tested the hypothesis that poplar leaf cuticles might contribute to non-host resistance to rust fungi by chemically impeding the germination and growth of urediniosporelings of Melampsora larici-populina. Following an initial survey in China of the resistance of 36 genotypes of various species and interspecific hybrids of Populus to M. larici-populina, we selected three genotypes for the initial test of hypothesis: (1) A Populus purdomii genotype that is fully susceptible; (2) a Populus deltoides cv. ‘I-69′ that is incompletely resistant (i.e., a resistant host); and (3) a Populus tomentosa genotype that is a non-host to M. larici-populina. Urediniospores were assayed for germination in extracts of the cuticles of the three genotypes. Germination was most reduced by the P. tomentosa non-host cuticular extracts that also reduced the growth of germ tubes to 36 times less than that in controls or in the extract of the susceptible P. purdomii. Four cuticular components were identified as putative defense compounds given greater concentrations in P. tomentosa than in P. purdomii: Aucubin, hexakis(trimethylsilyl) ether, catechol, 7,9-Di-tert-buty l-1-oxaspiro (4,5) deca-6, 9-diene-2,8-dione and trifluoroacetamide. These four compounds were then tested, and they reduced urediniospore germination and uredinial density in inoculations of normally susceptible P. purdomii with Melampsora larici-populina. Thus, the cuticle of P. tomentosa can contribute to pre-haustorial, non-host resistance to M. larici-populina.

scholarly journals Putative Rust Fungal Effector Proteins in Infected Bean and Soybean Leaves

2016 ◽  
Vol 106 (5) ◽  
pp. 491-499 ◽  
Author(s):  
Bret Cooper ◽  
Kimberly B. Campbell ◽  
Hunter S. Beard ◽  
Wesley M. Garrett ◽  
Nazrul Islam
Keyword(s):  
Plant Cell ◽  
Crop Production ◽  
Rust Fungus ◽  
Fungal Spores ◽  
Pathogenic Fungi ◽  
Rust Fungi ◽  
Effector Proteins ◽  
Glycoside Hydrolases ◽  
Data Set ◽  
Soybean Leaves

The plant-pathogenic fungi Uromyces appendiculatus and Phakopsora pachyrhizi cause debilitating rust diseases on common bean and soybean. These rust fungi secrete effector proteins that allow them to infect plants, but their effector repertoires are not understood. The discovery of rust fungus effectors may eventually help guide decisions and actions that mitigate crop production loss. Therefore, we used mass spectrometry to identify thousands of proteins in infected beans and soybeans and in germinated fungal spores. The comparative analysis between the two helped differentiate a set of 24 U. appendiculatus proteins targeted for secretion that were specifically found in infected beans and a set of 34 U. appendiculatus proteins targeted for secretion that were found in germinated spores and infected beans. The proteins specific to infected beans included family 26 and family 76 glycoside hydrolases that may contribute to degrading plant cell walls. There were also several types of proteins with structural motifs that may aid in stabilizing the specialized fungal haustorium cell that interfaces the plant cell membrane during infection. There were 16 P. pachyrhizi proteins targeted for secretion that were found in infected soybeans, and many of these proteins resembled the U. appendiculatus proteins found in infected beans, which implies that these proteins are important to rust fungal pathology in general. This data set provides insight to the biochemical mechanisms that rust fungi use to overcome plant immune systems and to parasitize cells.

scholarly journals XIX. On the specific heat and other physical characters of mixtures of ethylic alcohol and water

1869 ◽  
Vol 159 ◽  
pp. 591-614 ◽  
Keyword(s):  
Specific Heat ◽  
Royal Society ◽  
Unexpected Result ◽  
The One ◽  
Alcoholic Strength

The authors, having recently had occasion to estimate carefully the specific heat of mixtures of alcohol and water, came in the course of these experiments to the unexpected result that the specific heat of such mixtures, up to an alcoholic strength of about 36 per cent., is sensibly higher than the specific heat of water itself. These experiments, to the best of their knowledge, furnish the first example of a liquid having a higher specific heat than water, which has always been considered to possess the highest specific heat of any substance solid or liquid. They therefore beg leave to lay their results before the Royal Society. Two methods were employed for the estimation of the specific heat. The first method, and the one chiefly used, consisted in heating a metallic weight to a certain temperature, and then plunging it into the liquid whose specific heat was to be estimated; the rise in temperature thus produced in different liquids will, after the necessary corrections, be inversely proportional to the specific heat of these liquids.

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