100,820 research outputs found
Recent acquisition of Helicobacter pylori by Baka Pygmies
No full textBoth anatomically modern humans and the gastric pathogen Helicobacter pylori originated in Africa, and both species have been associated for at least 100,000 years. Seven geographically distinct H. pylori populations exist, three of which are indigenous to Africa: hpAfrica1, hpAfrica2, and hpNEAfrica. The oldest and most divergent population, hpAfrica2, evolved within San hunter-gatherers, who represent one of the deepest branches of the human population tree. Anticipating the presence of ancient H. pylori lineages within all hunter-gatherer populations, we investigated the prevalence and population structure of H. pylori within Baka Pygmies in Cameroon. Gastric biopsies were obtained by esophagogastroduodenoscopy from 77 Baka from two geographically separated populations, and from 101 non-Baka individuals from neighboring agriculturalist populations, and subsequently cultured for H. pylori. Unexpectedly, Baka Pygmies showed a significantly lower H. pylori infection rate (20.8%) than non-Baka (80.2%). We generated multilocus haplotypes for each H. pylori isolate by DNA sequencing, but were not able to identify Baka-specific lineages, and most isolates in our sample were assigned to hpNEAfrica or hpAfrica1. The population hpNEAfrica, a marker for the expansion of the Nilo-Saharan language family, was divided into East African and Central West African subpopulations. Similarly, a new hpAfrica1 subpopulation, identified mainly among Cameroonians, supports eastern and western expansions of Bantu languages. An age-structured transmission model shows that the low H. pylori prevalence among Baka Pygmies is achievable within the timeframe of a few hundred years and suggests that demographic factors such as small population size and unusually low life expectancy can lead to the eradication of H. pylori from individual human populations. The Baka were thus either H. pylori-free or lost their ancient lineages during past demographic fluctuations. Using coalescent simulations and phylogenetic inference, we show that Baka almost certainly acquired their extant H. pylori through secondary contact with their agriculturalist neighbors
Population demographic parameters for <i>H. pylori</i> from Baka Pygmies and non-Baka agriculturalists derived using an isolation-with-migration model and assuming two demographically explicit scenarios.
No full text<p>Population parameter theta (<i>θ</i>) = 4<i>N<sub>1</sub>μ</i>, where <i>N<sub>1</sub></i> is the effective population size of the reference population (non-Baka) and <i>μ</i> is the mutation rate. <i>t</i> is the timing parameter in coalescent units, and <i>T</i> the time to split between Baka and non-Baka (). <i>m</i> is the fraction of the population replaced by migrants per generation: of population 1 (non-Baka) are replaced per generation and of population 2 (Baka) are replaced per generation. The <i>θ</i> estimated by the software refers only to population 1. c.i., confidence interval; L, lower; U, upper.</p
Blood Press ure of Baka Pygmies Living in Southeastern Cameroon
No full textAfrican hunter-gatherers, Baka Pygmies (N = 276, ≥ 17 years of age) from the southeastern part of Cameroon participated in an assessment study of their blood pressure (BP) measurements. For comparison, data from 2 different Japanese populations (H with n = 632, and Y with n = 131 groups) were used. T here were no differences in systolic/diastolic BP in the Baka Pygmies with respect to the sex. A comparison of BP showed that neither systolic nor diastolic BP increased with age in Baka Pygmies, but it increased in the Y group (from 20 to 60 years). The average systolic/diastolic BP in Baka Pygmies (122.8 ± 10.9/71.2 ± 8.6 mmHg) was significantly lower than that of the H and the Y groups (126.1 ± 17.5/80.3 ± 11.3 and 131.6 ± 15.4/78.8 ± 9.9 mmHg, respectively). Most of the systolic and diastolic BP measurements in the H and the Y groups were classified high-normal or Grade 1 hypertension, whereas BP of most Baka Pygmies were classified as normal or optimal. These results revealed that an average BP of approximately 120/70 mmHg did not increase with age in Baka Pygmies living in the rainforest hunting and gathering for their living
Letter, [Author unclear] to Paulina T. Merritt
No full textHandwritten letter to Paulina Merritt from an unknown author, October 1, 1876.
Perbandingan tahap jangkitan Endoparasitedan rintangan terhadap Anthelmintic pada kambing baka Katjang dan kacukan Boer
No full textKajian ini dijalankan adalah untuk mengkaji tahap jangkitan endoparasite dan kesan rawatan athelmentics yang diberikan terhadap kambing baka Katjang dan Kacukan Boer yang terdapat di Ladang Kambing Fakulti Pertanian Lestari, Universiti Malaysia Sabah, Sandakan. Kajian ini dijalankan dengan menggunakan kaeclah Fecal Egg Count (FEC) laitu dengan mengkaji kekuatan jangkitan parasit yang berada dan membiak di dalam sistem pencemaan kambing baka Katjang dan Kacukan Boer. Kajian pertama, dijalankan bagl mengenal pasti tahap serangan parasit dalarnan terhadap kambing yang mempunyai baka yang berbeza iaitu Katjang dan Kacukan Boer. Dalam kajian ini, terdapat satu rawatan yang diberikan iaitu pengunaan ubat cacing, Albendazole 25 mg/L yang diberikan kepada kambing kedua-dua baka dengan menggunakan kaedah drenching. Berdasarkan hasil kajian, Boer menunjukkan tahap jangkitan yang lebih tinggi berbanding Katjang dengan jumlah purata Telur Per Gram (EPG) 345 ± 114, 290 ± 98 dan 278 ± 79 untuk 3 minggu berturut-turut berbanding Katjang dengan jumlah purata EPG 135 ± 77, 162 ± 75 DAN 208 ± 123. T-test yang dijalankan keatas keduadua jumlah pnilai purata diatas menunjukkan tiada menunjukkan tiada perbezaan ketara antara tahap jangkitan kambing katjang dan kacukan Boer. Hal ini jelas dilihat daripada nilai t stat < t crtitical two tail, -0.29< 12.71. Kajian keclua , dijalankan bagi mengenal pasti perbezaan kesan rawatan althelmenticsterhadap kambing Katjang dan kacukan Boer. Kajian ini dijalankan selama 12 minggu bagi melihat perjalanan tumbesaran dan bilangan telur cacing yang berada di dalam dalaman kambing keduadua baka. Kajian ini mendapati, kambing Katjang memberikan tindakbalas yang positif terhadap anthelmentics (Albendazole 25mg/L) yang diberikan dengan menunjukkan jumlah purata Telur Per Gram (EPG) yang sedikit dari minggu pertama sehingga minggu terakhir dengan jumlah purata keseluruhan 164 ± 85 berbanding kambing kacukan Boer dengan purata keseluruhan sebanyak 233 ± 82 EPG. Kawalan kepada penyakit endoparasite terhadap kambing ini disyorkan dijalankan secara berkala bagi mengelakkan sebarang penyakit kronik yang mungkin akan merosakkan system dalaman badan kambing sekali gus membawa kepada kematian. Inl juga adalah bagi mengurangkan keberjangkitan yang tinggi terhadap kambing di Ladang Kambing Fakulti Pertanian Lestari, Universiti Malaysia Sabah
En bordure de route (espace social, dynamisme et relation à l'environnement chez les pygmées Baka du sud-est Cameroun)
No full textAu tournant des années 1960, les Pygmées baka du Sud-Est Cameroun se regroupent massivement en bordure des routes et adoptent l'agriculture. Preuve d'un remarquable dynamisme, l'auteur entreprend l'analyse de ce double mouvement en questionnant deux caractéristiques ancestrales : quelle place la mobilité spatiale occupe-t-elle aujourd'hui dans l'organisation sociale et économique des Baka ? Pourquoi ces derniers, en venant s'établir en bordure de route, ont-ils constitué des groupes de dimension jamais encore observée auparavant ? Pour répondre a ces questions, l'auteur compare, en ayant recours à des quantifications précises, l'agriculture et la mobilité des Baka et celles de leur voisin, des Villageois depuis longtemps spécialisé en agriculture. Les limites de la typologie classique opposant agriculteur et chasseur-cueilleur sont révélées. L'analyse se recentre ensuite sur la société baka elle-même, en l'appréhendant comme une totalité. Pour ce faire, la mythologie, l'aménagement des espaces habités et cultivés, ainsi que les voies d'accès au village et les modalités de partage du gibier sont minutieusement décrits. Nous constatons alors que la représentations que le groupe se fait de lui-même et les observations faites de l'extérieur s'éclairent mutuellement, de sorte qu'il est possible d'identifier une cause qui serait à l'origine du regroupement des Baka en bordure de route. Les Baka illustrent ainsi non seulement leur remarquable capacité d'adaptation, mais encore nous révèlent la nécessité de considérer comme solidaire la relation des hommes à leur environnement matériel et spirituel, si l'on veut rendre compte du dynamisme des sociétés.In the 1960s, the Baka Pygmies from the South-Eastern Cameroon, massively, came to live on the border of the roads where they began agriculture. To analyse this double movement, two ancestral caracteristics are questioned : what is the importance of spatial mobility today ? On the road, why Baka Pygmies formed large groups never seen before ? To answer these questions, the autor compare the agriculture and the mobility of Baka as well as those of villagers, which are old specialists with agriculture. The limits of classical typology are reveled. After that, the Baka society itself, conceved as a whole, receive full attention : mythology, spatial organization of housing and culture, trails in forest and meat sharing modalities are described. We note that the own representation of the group, and the observations by outsiders are mutually completed. We can identify one important factor at the origin of the regroupment of the Baka. As a hunter and gatherer society, the Baka are an illustration not only of remarkable adaptation capacities, but also they reavel the necessity to consider jointly the relation of man to material environment and of man to spirits, if we want to analyse the dynamism of the societiesNANTERRE-BU PARIS10 (920502102) / SudocPARIS-Museum-Bib. ethnobiologie (751055206) / SudocSudocFranceF
Identification of novel genetic variants associated with short stature in a Baka Pygmies population
No full textHuman growth is a complex trait determined by genetic factors in combination with external stimuli, including environment, nutrition and hormonal status. In the past, several genome-wide association studies (GWAS) have collectively identified hundreds of genetic variants having a putative effect on determining adult height in different worldwide populations. Theoretically, a valuable approach to better understand the mechanisms of complex traits as adult height is to study a population exhibiting extreme stature phenotypes, such as African Baka Pygmies. After phenotypic characterization, we sequenced the whole exomes (WES) of a cohort of Baka Pygmies and their non-Pygmies Bantu neighbors to highlight genetic variants associated with the reduced stature. WES data analysis revealed 29 single nucleotide polymorphisms (SNPs) significantly associated with the reduced height in the Baka group. Among these variants, we focused on SNP rs7629425, located in the 5'-UTR of the Hyaluronidase-2 (HYAL2) gene. The frequency of the alternative allele was significantly increased compared to African and non-African populations. In vitro luciferase assay showed significant differences in transcription modulation of by rs7629425 C/T alleles. In conclusion, our results suggested that the HYAL2 gene variants may play a role in the etiology of short stature in Baka Pygmies population
Forest hunter-gatherers and their world: a study of the Mbendjele Yaka pygmies of Congo-Brazzaville and their secular and religious activities and representations
No full textThis thesis is about a forest hunter-gatherer people, the Mbendjele Yaka Pygmies of northern Congo-Brazzaville. The thesis is based on field research carried out between 1994 and 2001.
I begin by examining certain key terms used in the thesis and by situating my research within the existing literature. Research methodologies are presented and the fieldwork experience described. I provide an overview of the historical, political and economic context of the research including an outline assessment of the main historical reconstructions of regional history.
Conservationist and loggers' models of the forest are juxtaposed with Mbendjele ways of representing landscape and the forest environment. I discuss the significance of the forest in Mbendjele social experience and its role as the ideal environment for social life. I examine the way the Mbendjele classify animals and the cosmological significance of hunting and killing. This theme is continued with a presentation of ekila, a complex set of practices and beliefs that regulate the interactions of people with animals and express a complex relationship between human fertility and the correct handling of prey animals.
I continue the analysis of Mbendjele collective representations with a presentation of the activity of massana. The link between children's play and adult rituals implicit in the use of this term is analysed. I then build on this understanding to present an analysis of aspects of two ritual associations, Ejengi and Ngoku, central to men's and women's power in society.
The thesis is brought to a close by moving beyond the forest to examine Mbendjele relations with and conceptualisations of outsiders and property rights. New technological developments and financial incentives are increasingly transforming the Mbendjele forest into faunal and floral assets for distribution to international organizations
Handwritten biographical information on Paulina T. McClung Merritt
No full textA handwritten biography of Paulina T. McClung Merritt by an unknown author, 1892.
Heterogeneous and tissue-specific regulation of effector T cell responses by IFN-gamma during Plasmodium berghei ANKA infection.
No full textIFN-γ and T cells are both required for the development of experimental cerebral malaria during Plasmodium berghei ANKA infection. Surprisingly, however, the role of IFN-γ in shaping the effector CD4(+) and CD8(+) T cell response during this infection has not been examined in detail. To address this, we have compared the effector T cell responses in wild-type and IFN-γ(-/-) mice during P. berghei ANKA infection. The expansion of splenic CD4(+) and CD8(+) T cells during P. berghei ANKA infection was unaffected by the absence of IFN-γ, but the contraction phase of the T cell response was significantly attenuated. Splenic T cell activation and effector function were essentially normal in IFN-γ(-/-) mice; however, the migration to, and accumulation of, effector CD4(+) and CD8(+) T cells in the lung, liver, and brain was altered in IFN-γ(-/-) mice. Interestingly, activation and accumulation of T cells in various nonlymphoid organs was differently affected by lack of IFN-γ, suggesting that IFN-γ influences T cell effector function to varying levels in different anatomical locations. Importantly, control of splenic T cell numbers during P. berghei ANKA infection depended on active IFN-γ-dependent environmental signals--leading to T cell apoptosis--rather than upon intrinsic alterations in T cell programming. To our knowledge, this is the first study to fully investigate the role of IFN-γ in modulating T cell function during P. berghei ANKA infection and reveals that IFN-γ is required for efficient contraction of the pool of activated T cells
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