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B. Dasgupta

Bio: B. Dasgupta is an academic researcher from Government College. The author has contributed to research in topics: Petaurista magnificus. The author has an hindex of 1, co-authored 1 publications receiving 7 citations.

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B. Dasgupta1
TL;DR: The tissue stages and the erythrocytic stages of a malarial parasite infecting a flying squirrel of Darjeeling ( Petaurista magnificus) are described and a new genus, Rayella, is proposed to receive this parasite.
Abstract: The tissue stages and the erythrocytic stages of a malarial parasite infecting a flying squirrel of Darjeeling ( Petaurista magnificus ) are described. It is shown that this parasite cannot be accommodated in the existing genera of the malarial parasites of mammals ( Plasmodium, Hepatocystis and Nycteria ). A new genus, Rayella , is proposed to receive this parasite, which is named Rayella rayi (synonym: Plasmodium sp., Ray, 1949; Hepatocystis rayi , Tokura & Wu, 1961). The tissue stages of the parasite are represented by the groups of small schizonts in the form of cystic bodies, which occur in association with the smaller blood-vessels of the liver. The author is grateful to Professor P. C. C. Garnham of the London School of Hygiene and Tropical Medicine, London, for his interest and valuable advice. The author wishes to record his special thanks to Professor H. N. Ray who kindly placed the relevant literature and his slides and drawings at the disposal of the author. Professor Ray's unpublished drawings of the erythrocytic stages of the malarial parasite of the flying squirrel ( Petaurista inornatus ) are reproduced here with his special permission.

7 citations


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TL;DR: Polychromophilus' ancestor was most likely a bird- or reptile-infecting Plasmodium before it switched to bats, and the invasion of mammals as hosts has not been a unique event in the evolutionary history of Haemosporida, despite the suspected costs of adapting to a new host.
Abstract: The majority of Haemosporida species infect birds or reptiles, but many important genera, including Plasmodium, infect mammals. Dipteran vectors shared by avian, reptilian and mammalian Haemosporida, suggest multiple invasions of Mammalia during haemosporidian evolution; yet, phylogenetic analyses have detected only a single invasion event. Until now, several important mammal-infecting genera have been absent in these analyses. This study focuses on the evolutionary origin of Polychromophilus, a unique malaria genus that only infects bats (Microchiroptera) and is transmitted by bat flies (Nycteribiidae). Two species of Polychromophilus were obtained from wild bats caught in Switzerland. These were molecularly characterized using four genes (asl, clpc, coI, cytb) from the three different genomes (nucleus, apicoplast, mitochondrion). These data were then combined with data of 60 taxa of Haemosporida available in GenBank. Bayesian inference, maximum likelihood and a range of rooting methods were used to test specific hypotheses concerning the phylogenetic relationships between Polychromophilus and the other haemosporidian genera. The Polychromophilus melanipherus and Polychromophilus murinus samples show genetically distinct patterns and group according to species. The Bayesian tree topology suggests that the monophyletic clade of Polychromophilus falls within the avian/saurian clade of Plasmodium and directed hypothesis testing confirms the Plasmodium origin. Polychromophilus' ancestor was most likely a bird- or reptile-infecting Plasmodium before it switched to bats. The invasion of mammals as hosts has, therefore, not been a unique event in the evolutionary history of Haemosporida, despite the suspected costs of adapting to a new host. This was, moreover, accompanied by a switch in dipteran host.

34 citations

Journal ArticleDOI
01 Jun 2016
TL;DR: A thorough review on biology and conservation status of flying squirrels in India is provided in this paper, where a total of 13 flying squirrel species are present in India i.e., Belomys pearsonii, Biswamoyopterus biswasi, Eupetaurus cinereus, Eoglaucomys fimbriatus, Hylopetes alboniger, Petaurista elegans, P. magnificus and Petinomys fuscocapillus.
Abstract: Flying squirrels are capable of gliding and one of the least known mammals of the world. Work on these animals is less and sporadic due to their crepuscular and cryptic habits. At the present scenario, a complete pilot study is in an urgent need to formulate conservation strategies and policies to conserve them in India. Therefore, a thorough review on biology and conservation status of flying squirrels in India is provided here. A total of 13 species of flying squirrels present in India i.e., Belomys pearsonii, Biswamoyopterus biswasi, Eupetaurus cinereus, Eoglaucomys fimbriatus, Hylopetes alboniger, Petaurista elegans, P. mishmiensis, P. magnificus, P. mechukaensis, P. nobilis, P. petaurista, P. philippensis and Petinomys fuscocapillus, wherein three are endemic to the country. P. philippensis has broader distribution and is found to be more studied than others. Eastern part of the country contains the highest species number (n = 10) follows three in northern part, two in southern part and one in western part subsequently. All species are facing threat to their population due to native habitat loss, degradation and hunting. Harmonization, alliances and partnership between various stakeholders along with better application of standard techniques would be strengthen to develop conservation strategies and implementing their coordinated actions could preserve flying squirrels’ future in the country landscape.

10 citations

Journal ArticleDOI
TL;DR: The results of this study failed to determine the duration of the asexual cycle of the parasite, and further attempts were unsuccessful because of the high mortality of the flying squirrels in captivity.
Abstract: A new species of malaria Plasmodium watteni has been found in the Formosan giant flying squirrel, Petaurista petaurista grandis. It is similar to P. booliati from the Malayan flying squirrel except that the trophozoites and schizonts do not exhibit a vacuolated or foamy appearance; the pigment in the trophozoites and gametocytes is more conspicuous and abundant; the mature schizont nearly fills the host cell and has a maximum of 18 merozoites; and the gametocytes fill the host cell. Laboratory rats, mice, hamsters, guinea pigs, the Taiwan monkey (Macaca cyclopis) as well as splenectomized rats and guinea pigs were resistant to experimental transfusion infections. Periodicity studies in the flying squirrel carried out over a 9-day period failed to show synchronism in the asexual cycle of the parasite. During the course of field investigations for parasites of the blood of lower animals in Taiwan, an undescribed species of Plasmodium was found in the Formosan giant flying squirrel, Petaurista petaurista grandis. The senior author first found the parasite in four animals in November 1964 and January 1965 (Sandosham et al., 1965). In further studies since December 1966 additional specimens have been obtained from a number of flying squirrels and the present paper describes the erythrocytic stages of this new species of malaria. MATERIALS AND METHODS Petaurista petaurista grandis (Swinhoe, 1862) is one of the commonest species of the subfamily Petauristainae of the family Sciuridae found on the island of Taiwan. According to Horikawa (1931) this animal inhabits forested hilly areas with elevations of 100 to 2,500 m. It is nocturnal and seen more frequently at night in the tops of trees. In the daytime it retires into large tree holes. Its diet consists of fruits and young leaves. Blood smears were obtained from captured animals or from animals shot from treetops. Thick and thin blood smears were stained with buffered Giemsa at pH 7. Heparinized blood containing the parasite was obtained from one flying squirrel and inoculated into another squirrel in which preinoculation blood smears were found to be negative. Attempts were made to determine the asexual cycle of the parasite by obtaining blood smears at Received for publication 31 May 1968. * The opinions and assertions contained herein are those of the authors and are not to be construed as official or reflecting the views of the Navy Department or the Naval Service at large. This study was supported in part by funding under Public Law 480, Section 104(c), and in part through funds provided by the Bureau of Medicine and Surgery, Navy Department, for Work Unit MF022.03.07-2018. 4-hr intervals for 9 days. The results of this study failed to determine the duration of the asexual cycle of the parasite, and further attempts were unsuccessful because of the high mortality of the flying squirrels in captivity. In an effort to find exoerythrocytic stages of the parasite, serial sections of the livers of five squirrels were examined histologically. No exoerythrocytic stages were found. In other studies parasitized blood was inoculated into 3to 4-week-old laboratory rats, mice, hamsters, guinea pigs and one adult Taiwan monkey (Macaca cyclopis). In addition, experimental infections were attempted in splenectomized rats and guinea pigs. Infection failed to develop in any of these laboratory animals. Plasmodium (Vinckeia) watteni sp. n. (Figs. 1-35) Vertebrate host: Petaurista petaurista grandis (Swinhoe, 1862). Invertebrate host: Not known. Locality: Peiyuan, Tungho Township, Taitung Hsien, Taiwan Province, Republic of China. Date of collection of type host: 1 February 1967. Type material: The morphological description of this species is based on a study of Giemsa-stained blood films obtained at 4-hr intervals for 9 days from a flying squirrel which received a secondary passage of the parasitized blood. The type slides will be deposited in the Department of Medical Ecology, U. S. Naval Medical Research Unit No. 2, Taipei, Taiwan, Republic of China. This malaria parasite is named in honor of Captain R. H. Watten, MC, U. S. Navy, Commanding Officer of the U. S. Navy Medical Research Unit No. 2, Taipei, Taiwan, for his encouragement and interest in parasitology. Description of the erythrocytic stages Host cell (Fig. 1): Uninfected host erythrocytes 4.6 to 7.0 ,L in diameter, average 5.4 Au. Parasitized

5 citations

Journal ArticleDOI
TL;DR: The merocysts found in the two different species of flying squirrels are considered to belong to two separate parasites, one of which is identified as H. inornatus and the other is designated H. magnificus, a new subspecies named in honour of Dr Wu Chen-Lan who worked on flying squirrel malaria in Formosa.
Abstract: Merocysts in P. inornatus are found in the liver, spleen and lungs, while in P. magnificus the liver is the only site. In the former the protoplasmic rim is narrow and the merozoites are sparsely distributed within it; in the latter the protoplasmic rim is irregular, quite thick and broken in places. In the former, the colloidal mass is scanty, and is in the form of tenuous matrix enclosing irregular interspaces; in the latter form, the colloidal mass is in the form of homogeneous substance with little vacuolation. In view of the wide differences in the structure and the site of occurrence, the merocysts found in the two different species of flying squirrels are considered to belong to two separate parasites. The parasite occurring in P. inornatus is identified as H. rayi rayi Tokura & Wu, sensu stricto, while the other parasite occurring in P. magnificus is designated H. rayi wui, a new subspecies, named in honour of Dr Wu Chen-Lan who worked on flying squirrel malaria in Formosa.

2 citations