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1.
Tinde Van Andel 《Economic botany》2010,64(1):1-10
African Rice (
Oryza glaberrima
Steud.): Lost Crop of the Enslaved Africans Discovered in Suriname. African rice (Oryza glaberrima Steud.) was introduced to the Americas during the slave trade years and grown by enslaved Africans for decades before mechanical
milling devices facilitated the shift towards Asian rice (O. sativa L.). Literature suggests that African rice is still grown in Guyana and French Guiana, but the most recent herbarium voucher
dates from 1938. In this paper, evidence is presented that O. glaberrima is still grown by Saramaccan Maroons both for food and ritual uses. Saramaccan informants claim their forefathers collected
their first “black rice” from a mysterious wild rice swamp and cultivated these seeds afterwards. Unmilled spikelets (grains
with their husk still attached) are sold in small quantities for ancestor offerings, and even exported to the Netherlands
to be used by Maroon immigrants. Little is known of the evolution of O. glaberrima, before and after domestication. Therefore, more research is needed on the different varieties of rice and other “lost crops”
grown by these descendants of enslaved Africans who escaped from plantations in the 17th and 18th centuries and maintained
much of their African cultural heritage in the deep rainforest. 相似文献
2.
Summary Freshwater crabs (Potamonautes perlatus) are the largest naturally occurring invertebrates in southern African rivers. The ecology of these animals in South African riverine ecosystems is little understood. This study investigates some aspects of the population and feeding ecology of P. perlatus in the upper reaches of the Buffalo River. The densities of crabs (carapace width larger than 25 mm) at two sites in the river ranged between 1.72 and 5.25 crabs m2, higher than previously recorded for freshwater crabs in rivers in southern Africa and southern Italy. Twenty-four hour observations revealed that P. perlatus has a nocturnal habit. The diet of P. perlatus was established by examination of the contents of the fore-gut. Crabs with a carapace width smaller than 40 mm fed predominantly on aquatic invertebrates while larger crabs fed on allochthanous material (leaf litter), detritus and algae. Through feeding, crabs reduced the surface area of leaves in the stream by 99.95%. 相似文献
3.
J. A. Thornton 《African Journal of Aquatic Science》2013,38(2):49-53
SUMMARY In accordance with the Silver Jubilee theme of ‘reminisce and assess’, the editorial takes a critical look at the Journal of the Limnological Society of Southern Africa with the objective of examining its raison d'etre. After briefly examining the need for a journal in the context of southern African limnology and oceanography, an analysis of the strengths, weaknesses, opportunities and threats facing the Journal is conducted. As a result of this analysis, a mission statement and action plan for the continued development of a useful and relevant publication, reflecting the needs and concerns of the total membership of the Limnological Society of Southern Africa, are presented. This approach places the Journal on a sound strategic footing and gives substance to the extended scope of the Journal which, since 1986, has included contributions from freshwater, estuarine and coastal marine scientists. A change in title to the Southern African Journal of Aquatic Sciences is announced - the change will take effect in 1989 with volume 15. 相似文献
4.
C. BUDDE 《Bioacoustics.》2013,22(2-3):191-201
ABSTRACT This paper presents the acoustic features and the behavioural context of the unison call of the East African Crowned Crane Balearica regulorum gibbericeps. It speculates on the different functions of the unison call according to the situations where it is given. This is tested with the appeasement-threat hypothesis, which claims that the threatening acoustic characteristics of the unison call should be enhanced if it is given as a territorial call. In comparison, the appeasing acoustic characteristics should be stronger if the unison call is performed at flock sites where it possibly serves for mate assessment. 相似文献
5.
FRANÇOISE DOWSETT-LEMAIRE 《Ibis》1979,121(4):453-468
This paper presents the first extensive evidence of vocal imitations of African birds by a Palaearctic migrant, the Marsh Warbler Acrocephalus palustris. Nearly 30 individual tape recorded repertoires have been analysed, most of them from Belgium; imitations of each identified species were compared to models by spectrographic analysis. A list of 113 African species (33 non-passerines, 80 passerines) was thus established (Appendix), which, added to the list of 99 European species, gives a total imitative range of 212 species. The low-pitched voices of many non-passerines exclude them from imitation. Vocal imitations of some rather local species in East Africa provide information on the localization of the autumn and winter quarters of A. palustris. In particular, the frequency of imitations of such species as Vinaceous Dove Streptopelia vinacea, Boran Cisticola Cisticola bodessa and Red-pate Cisticola C. ruficeps lends support to the idea of the existence of autumn quarters in northeastern Africa. Individual repertoires contain an average of 76.2 different imitated species (extremes 63–84), the number of African species (average 45.0) exceeding that of European species (average 31.2). About a fifth of the complete song remains unidentified and probably corresponds to imitations of African birds whose voices have not yet been recorded. The most recurrent imitations are those of noticeably noisy species, widespread in Africa. A. palustris appears not to be selective in its repertoire. Imitations of different species can, to some extent, be combined and alternated into original motifs. Circumstantial evidence indicates that the young A. palustris are still learning song motifs when on their way to their winter quarters and probably stop learning soon after their arrival there, most of them in January, at the age of 6–7 months. There is a temporal separation between the sensitive phase and the motor phase of song learning. No conclusion as to the possible functions of the imitative element of the song can be drawn at present. 相似文献
6.
Detection and characterization of the African citrus greening Liberobacter by amplification,cloning, and sequencing of the rplKAJL-rpoBC operon 总被引:2,自引:0,他引:2
Pascale Planet Sandrine Jagoueix Joseph M. Bové Monique Garnier 《Current microbiology》1995,30(3):137-141
Greening disease of citrus is caused by a phloem-restricted, uncultured bacterium, recently characterized and named Liberobacter. As shown previously, a probe encoding ribosomal protein genes (rplKAJL-rpoBC operon) from an Asian liberobacter could detect all Asian liberobacter strains tested, but not African strains. Using the sequence of the rplKAJL-rpoBC operon of the Asian liberobacter strain from Poona (India), we have defined primers for PCR amplification of the equivalent genes of an African liberobacter strain. The amplified fragment was cloned in pUC18 and successfully used as a probe to detect African liberobacter strains by Southern and dot hybridizations. Sequence comparisons of the African and Asian liberobacter operons indicate that they represent two different species in the proposed genus Liberobacter. 相似文献
7.
Gervas Clay 《Ostrich》2013,84(2):76-97
Dean, W. R. J. 1978. Moult seasons of some Anatidae in the western Transvaal. Ostrich 49:76-84. Spurwinged Geese Plectropterus gambensis, Egyptian Geese Alopochen aegyptiacus, Yellow-billed Ducks Anas undulata, Redbilled Teal A. erythrorhyncha and Southern Pochard Netta erythrophthalma have a flightless moult mainly during the dry season, from April to August, in the western Transvaal. South African Shelduck Tadorna cana moult during October to February after breeding during July and August. The Cape Shoveller Anas smithii has two main flightless periods, April-May and October-January. Cape Teal A. capensis have been recorded in flightless moult in October, December and January. The duration of the flightless period correlates with wing length; larger and longer winged Anatidae require proportionally more time for wing moult than do smaller and shorter winged Anatidae. Geese and shelducks moult on large open lakes with an open shore. Ducks have been recorded flightless on lakes and dams, with or without emergent vegetation. 相似文献
8.
《Journal of bryology》2013,35(2):199-209
AbstractA new species, Nanobryum thorsbornei, is described from northern Queensland, Australia, and compared with N. dummeri, an African species to which it seems most closely allied. They both have a remarkable persistent protonema which is partly pseudothallose but the leaves of the Australian species are trilobate, a feature lacking in the African species. The relationship of Nanabryum with Fissidens, particularly F. gladiolus, is discussed. 相似文献
9.
《Endocrine practice》2012,18(6):947-953
ObjectivesVitamin D deficiency is more common in African Americans than in the general population or other ethnicities. Vitamin D deficiency also occurs more frequently in patients with primary hyperparathyroidism (PHPT) than in the general population. Currently, the limited data on vitamin D deficiency in African Americans with primary hyperparathyroidism (PHPT) is inconsistent as to whether the vitamin D deficiency observed in PHPT is yet even more pronounced in Africans with PHPT relative to non-African Americans with PHPT.MethodsOn the basis of biochemical, radiological, and surgical (adenoma weight) parameters, African Americans have been reported to have a more severe form of PHPT than non-African Americans. However, comparative clinical manifestations of PHPT in African Americans have not been well described.ResultsCurrent guidelines recommend vitamin D repletion in mild, asymptomatic PHPT when levels of 25-hydroxyvitamin D are less than 20 ng/mL. Studies that reported vitamin D repletion with ergocalciferol or cholecalciferol in PHPT have not stratified data according to ethnicity. Discrepancies therefore exist between repleting vitamin D in African Americans who may potentially have a more severe PHPT profile, but simultaneously a more pronounced vitamin D deficiency.ConclusionEffectively designed clinical trials are necessary to evaluate the indications, efficacy, and safety of vitamin D in African Americans with PHPT. (Endocr Pract. 2012;18:947-953) 相似文献
10.
11.
P. A. R. Hockey 《Ostrich》2013,84(4):244-247
Summary Hockey, P. A. R. 1981. Morphometries and sexing of the African Black Oystercatcher. Ostrich 52: 244–247. 109 African Black Oystercatchers Haematopus moquini were caught, measured and sexed by cloacal examination during the 1979/1980 breeding season. Six standard taxonomic variables were measured. Females were larger than males in all dimensions considered. The most dimorphic characters were mass and exposed culmen length. The data were subjected to stepwise discriminant analysis and a linear function was derived which allowed birds of unknown sex to be sexed. The function is D = ?0,391x1 ?0,016 x2 +0,218 x3 +0,714 x4 +15,946 where x1 = exposed culmen length (mm), x2 = body mass (g), x3 = length of tarsometatarsus (mm) and x4 = culmen depth at the gonys. Values of D from the above equation less than zero indicate a female while those greater than zero indicate a male. The greater the divergence of D from zero, the higher the probability of correctly sexing an unknown individual: once D> ± 1,2, p>0,99. 相似文献
12.
R. K. Owen 《African Journal of Aquatic Science》2013,38(1-2):148-152
Summary The ocypodid genus Paratylodiplax was described in 1974 and contains four species, three of which are endemic to southern Africa where they form an important component of the estuarine benthic fauna. However, very little is known about the biology and ecology of the genus, with discrepancies existing between the commonly quoted distributions and actual records of the species. This comment outlines the current taxonomic status of the genus and attempts to resolve the discrepancies in the distributions of the southern African species Paratylodiplax blephariskios has been recorded from the Morrumbene estuary in Mozambique to the Mngazana estuary in the eastern Cape, while the distributions of P. algoensis and P. edwardsii are given as being from the Mngazana to the Eerste estuary and Langebaan Lagoon in the western Cape respectively. 相似文献
13.
P. A. Clancey 《Ostrich》2013,84(1):23-24
Summary Hustler, K. &; Marshall, B.E. 1996. The abundance and food consumption of piscivorous birds on Lake Kariba, Zimbabwe-Zambia. Ostrich 67:23-32. About 40 species of piscivorous birds have been recorded on Lake Kariba (Zimbabwe-Zambia) but only 26 were observed during this study, carried out in 1986–87. The Reed Cormorant Phalacrocorax africanus was the most numerous and made up 51.4% of all the birds seen, followed by the Whitewinged Black Tern Chlidonias leucoptera (26.7%), and the Darter Anhinga melanogaster (10.8%). Several species roosted or bred in the drowned trees which project above the lake surface but gently sloping shores were the most important feeding grounds. Relatively few birds were seen on steeply sloping shores or in open water. There was a distinct pattern of seasonal abundance, with birds being most numerous in the rainy season (November-April). The relative abundance of some fish species also was greatest during this period. There was a positive relationship between the numbers of some bird species and the relative abundance of these fish. The mean density of piscivores (0.05 ha?1) was low compared to some other African waters. This is attributed to the fact that Lake Kariba is relatively deep and its shoreline is mostly steep. The mean population of 25 000 birds consumed less than 1000 t of fish per annum, compared to almost 40000 t taken by the commercial fisheries. A considerable portion of the birds' diet was fish that were not taken commercially. 相似文献
14.
Revel Iyer Enrico M. Tronchin John J. Bolton Vernon E. Coyne 《Journal of phycology》2005,41(3):672-684
Southern Africa has economically exploited populations of terete gracilarioids on the cool temperate west coast and numerous species of endemic and Indo‐Pacific tropical Gracilariaceae on the south and east coasts. Gross morphological characters have been the main means of identification, and incorrect applications have led to a number of misidentifications. In this study, small subunit rDNA and RUBISCO spacer sequences were used to determine phylogenetic relationships. Whereas rDNA sequences successfully differentiate major groups within the family as well as species belonging to the Gracilariopsis and the Curdiea/Melanthalia clade, RUBISCO spacer sequencing was required to distinguish between species of Gracilaria. The southern African gracilarioid complex (stringy, terete, elongate members of the Gracilariaceae) was resolved into three species: Gracilaria gracilis, Gracilariopsis longissima, and Gracilariopsis funicularis. South African Gracilaria protea was shown to be conspecific with tropical Indian Ocean G. corticata. Apart from G. gracilis and G. corticata, South African Gracilaria species were differentiated into a temperate‐tropical terete grouping and a temperate‐tropical flattened grouping. 相似文献
15.
《Journal of bryology》2013,35(4):257-263
AbstractSouth African populations of Bryobartramia have been treated as B. novae-valesiae, a species otherwise restricted to Australia. However, material from the two regions differs in a number of traits, and the African populations are here described as a new species, B. schelpei. The Cape species differs most obviously from B. novae-valesiae in the markedly prorate-papillose, narrow, thick-walled cells of the calyptra. Nested analysis of variance reveals further morphometric differences, including the relatively narrower, more cylindrical, calyptra with a longer rostrum, and the smaller leaf cells and spores. Bryobartramia schelpii is known only from arid portions of the winter rainfall region in the Northern and Western Cape Provinces of South Africa. 相似文献
16.
Rauscher GM Smart CD Simko I Bonierbale M Mayton H Greenland A Fry WE 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2006,112(4):674-687
Phytophthora infestans, the causal agent of late blight, threatens potato production worldwide. An important tool in the management of the disease
is the use of resistant varieties. Eleven major resistance genes have been identified and introgressed from Solanum demissum. However, new sources of resistance are continually sought. Here, we report the characterization and refined genetic localization
of a resistance gene previously identified as Rber in a backcross progeny of Solanum tuberosum and Solanum berthaultii. In order to further characterize Rber, we developed a set of P. infestans isolates capable of identifying each of the 11 R-genes known to confer resistance to late blight in potato. Our results indicate
that Rber is a new resistance gene, different from those recognized in S. demissum, and therefore, it has been named R
Pi-ber
according to the current system of nomenclature. In order to add new molecular markers around R
Pi-ber
, we used a PCR-based mapping technique, named MASP-map, which located R
Pi-ber
in a 3.9 cM interval between markers CT240 and TG63 on potato chromosome X. The location of R
Pi-ber
coincides with an area involved in resistance to different pathogens of potato and tomato. 相似文献
17.
Abstract The morphology of a new species of Hyphomorpha, Borzi, collected from 3,300 metres above sea level underneath a rock in Singalila Range along Eastern Himalayas, has been studied and named as Hyphomorpha borzii. The relationship, affinities and taxonomy of the alga have been critically discussed at the end. 相似文献
18.
C. BUDDE 《Bioacoustics.》2013,22(2-3):161-173
ABSTRACT The study describes the vocal repertoire of the Grey Crowned Crane Balearica regulorum gibbericeps and speculates on the purpose the calls serve. The repertoire consists of 4 tonal and 7 non-harmonic calls. Chicks have 3 different vocalizations. 相似文献
19.
【背景】斑鸠霉素及其氧化衍生物属于多环特特拉姆酸大环内酰胺类化合物,具有良好的生物活性,挖掘更多新颖斑鸠霉素类似物具有重要意义。细胞色素P450氧化酶CftA被认为能催化斑鸠霉素的氧化反应,但未有相关体外实验数据的报道。【目的】通过体外生化实验鉴定氧化酶CftA的功能,并探索其催化斑鸠霉素氧化反应的机制。【方法】利用基因合成的方法直接克隆斑鸠霉素氧化酶基因cftA,于大肠杆菌中诱导表达后,纯化蛋白进行体外酶反应,利用高效液相色谱与高分辨质谱联用技术鉴定酶反应产物。【结果】在体外,氧化酶CftA催化斑鸠霉素生成一个新的氧化衍生物Hydroxyikarugamycin D和一个已知氧化衍生物Clifednamide A。【结论】进行了细胞色素P450氧化酶CftA的体外生化研究,证实其能特异性催化斑鸠霉素C29位的两步氧化反应,为进一步探索斑鸠霉素P450氧化酶的催化机制,以及通过生物酶催化拓展斑鸠霉素类多环特特拉姆酸大环内酰胺化合物的结构多样性奠定了基础。 相似文献