Chromosome cycle in the gregarine Stylocephalus mesomorphi Dev.

Parasitology ◽  
1966 ◽  
Vol 56 (2) ◽  
pp. 199-208
Author(s):  
R. N. Desai

The gregarine Stylocephalus mesomorphi has a diploid chromosome number of 8. The diploid stage is represented only by the zygote nucleus before the metagamic divisions start. The other stages in the entire life history of this gregarine are haploid.The mitotic chromosomes are four in number, one being the longest, two of medium size and the fourth the smallest.I am grateful to Professor J. C. Uttangi, Head of the Zoology Department, Karnatak Science College, Dharwar, for the encouragement he gave me throughout this work. I am also greatly indebted to my colleague Dr M. J. Devadhar, for having given me many valuable suggestions.

1898 ◽  
Vol 63 (389-400) ◽  
pp. 56-61

The two most important deviations from the normal life-history of ferns, apogamy and apospory, are of interest in themselves, but acquire a more general importance from the possibility that their study may throw light on the nature of alternation of generations in archegoniate plants. They have been considered from this point of view Pringsheim, and by those who, following him, regard the two generations as homologous with one another in the sense that the sporophyte arose by the gradual modification of individuals originally resemblin the sexual plant. Celakovsky and Bower, on the other hand, maintaint the view tha t the sporophyte, as an interpolated stage in the life-history arising by elaboration of the zygote, a few thallophytes.


2007 ◽  
Vol 59 (3) ◽  
pp. 227-231 ◽  
Author(s):  
S. Zivkovic ◽  
M. Devic ◽  
B. Filipovic ◽  
Z. Giba ◽  
D. Grubisic

The influence of high NaCl concentrations on seed germination in both light and darkness was examined in the species Centaurium pulchellum, C. erythraea, C. littorale, C. spicatum, and C. tenuiflorum. Salt tolerance was found to depend on the life history of the seeds. To be specific, seeds of all five species failed to complete germination when exposed to continuous white light if kept all the time in the presence of 100-200 mM and greater NaCl concentrations. However, when after two weeks NaCl was rinsed from the seeds and the seeds were left in distilled water under white light for an additional two weeks, all species completed germination to a certain extent. The percent of germination not only depended on NaCl concentration in the prior medium, but was also species specific. Thus, seeds of C. pulchellum, C. erythraea, and C. littorale completed germination well almost irrespective of the salt concentration previously experienced. On the other hand, seeds of C. tenuiflorum completed germination poorly if NaCl concentrations in the prior media were greater than 200 mM. When seeds after washing were transferred to darkness for an additional 14 days, they failed to complete germination if previously imbibed on media containing NaCl concentrations greater than 400 mM. However, the seeds of all species, even if previously imbibed at 800 mM NaCl, could be induced to complete germination in darkness by 1 mM gibberellic acid. .


Author(s):  
Patricia M. Lambert

In 1989, a pioneer cemetery associated with the 19th-century Latter-Day Saints colony in San Bernardino, California, was discovered during the construction of a baseball field. Among the remains of 12 individuals recovered from the cemetery were those of a young man of about 22 years, whose burial treatment differed notably from the other intact interments at the site. Unlike these coffin burials, Burial 5 was found in a sprawling position, apparently tossed unceremoniously into the grave pit. Dental morphological traits identified the genetic affinities of this man as Native American, perhaps a member of the local Cahuilla or Serrano tribes, whereas the other individuals appeared to be of European ancestry, an interpretation consistent with records kept by community members. A possible identity for this individual came from a journal account describing the shooting of an “Indian” by the local sheriff, who was then brought to the fort, died, and was buried before his fellow tribesmen arrived to determine what had transpired and perhaps to claim his remains. This chapter explores the identity and life history of this young man in the context of the history of the valley and the pioneer community in which he met his death.


1902 ◽  
Vol 23 ◽  
pp. 319-358
Author(s):  
R. Stewart MacDougall

In the case of any harmful insect of economic importance, in order to war against it, or apply remedial measures at all intelligently, a knowledge of the life-history of the pest is necessary. This proposition will, I think, meet with such ready acceptance as to render proof unnecessary, but I might in illustration mention two cases which came under my own observation, where in the one case a knowledge of the round of life of the attacking insect saved a whole forest, and in the other proved of great importance.


1976 ◽  
Vol 54 (24) ◽  
pp. 2903-2906 ◽  
Author(s):  
J. P. van der Meer

Palmaria palmata from a region of the Atlantic coast of Canada has been examined cytologically. Plants bearing tetrasporangia were found to be diploid with meiosis occurring in the tetrasporangia. Spermatangial plants and sporelings growing from tetraspores were haploid. The haploid chromosome number appears to be 22–23.


2017 ◽  
Vol 11 (3) ◽  
Author(s):  
Mark Gamsa

AbstractThis article has two goals. It reflects on the recent developments and agenda of an approach to historical writing that is now becoming known by the name global microhistory, and it analyses the attention which this approach pays to individual lives. It also explores some of the challenges in writing the biography of a city alongside the life history of a person. The city is Harbin, a former Russian-managed railway hub in Manchuria, today a province capital in Northeast China. The person is Baron Roger Budberg (1867–1926), a physician of Baltic German origin who arrived in Harbin during the Russo-Japanese war and remained there until his death, leaving published works and unpublished correspondence in German and Russian. My forthcoming book about Budberg and Harbin challenges the distinction between writing “biography”, on the one hand, and “history”, on the other, while navigating between the “micro” and “macro” layers of historical enquiry.


1993 ◽  
Vol 6 (5) ◽  
pp. 377 ◽  
Author(s):  
AK Wells ◽  
RS Hill

It is known that epiphyllous microorganisms have the potential to provide important information about palaeoclimates and palaeohabitats. Previous studies have shown one of the major candidates, fungal 'germlings', to be possibly climatically sensitive. In this study we demonstrate that at least two organisms are present as germlings, one an epiphyte and the other a saprophyte. While there is some evidence to support the hypothesis that grades of germlings represent a sequence of developmental steps, most data either refute this hypothesis or neither refute nor support it. We show that grade 1 and 2 germlings are unlikely to be reliable for predictive purposes, since their presence is not consistent among host species, and they may represent saprophytes as well as epiphytes. The ecology and life history of germlings is complex, and more data are required on these factors before they can be used for predictive purposes.


Parasitology ◽  
1963 ◽  
Vol 53 (1-2) ◽  
pp. 201-215 ◽  
Author(s):  
Gwendolen Rees

1. A plerocercoid of ‘Acanthotaenia’ has been found in large numbers in ‘cysts’ in the pancreas of Rana occipitalis (Günther) in Ghana.2. ‘Cysts’ containing plerocercoids were fed to Varanus niloticus (L.). Adults of Proteocephalus niloticus (Beddard) were recovered from the intestine 3 weeks later.3. It is suggested that the life cycle involves three hosts, the first being a copepod.4. The morphology of the larva and adult is described.I wish to express my sincere gratitude to the authorities of the University of Ghana for inviting me to spend some time in the Zoology Department there. I am most grateful, also, to Professor R. D. Purchon for his kindly interest and for the facilities which he placed at my disposal. It is a pleasure to thank Dr J. D. Thomas and the technical staff for their assistance in the collection of material.


2019 ◽  
Vol 8 ◽  
Author(s):  
Susan M Kenyon

Drawing on long-term ethnographic research in the Blue Nile town of Sennar, supported by archival and historical documentation, this article explores the history of Zar spirit possession in Sudan, and the light this throws on the interplay of religions over the past 150 years. Life history data supports the argument that contemporary Zar is grounded in forms and rituals derived from the ranks of the ninteenth-century Ottoman army, and these remain the basis of ritual events, even as they accommodate ongoing changes in this part of Africa. Many of these changes are linked to the dynamic interplay of Zar with forms of Islam, on the one hand, and Christianity, on the other. In the former colonial periods, political power resided with the British, and Khawaja (European) Christian Zar spirits are remembered as far more important. Today that authority in Zar has shifted to spirits of foreign Muslims and local holy men, on the one hand, and to subaltern Blacks, on the other. These speak to concerns of new generations of adepts even as changes in the larger political and religious landscapes continue to transform the context of Zar.


Author(s):  
Vincent Joos

Abstract This article explores the life history of Ulrick Rosarion, a Haitian federal prosecutor who built his career during the Duvalier dictatorship. Rosarion lived his entire life in a small house of downtown Port-au-Prince, in a neighborhood formerly inhabited by the Black middle-classes that gained prominence in the political and administrative sphere during the dictatorship (1957-1986). Rosarion was also a writer who produced four books of nationalist poetry. Based on interviews and readings of his literary production, and beyond, through an exploration of architectural forms and material remnants echoing the dictatorship, this paper explores how an idealized version of the dictatorship today haunts the political landscape of Haiti. Moreover, this article argues that the state takes on a sensual form that allows for the diffusion and/or rupture of past ideologies.


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