The degree of intergradation between two species of Sulawesi macaques,Macaca tonkeana andM. hecki, was studied by examining the diagnostic external characteristics of more than 100 monkeys kept as pets by natives. Two possible
hybrid monkeys were found and both originated from the borderland between the two species, located in the most proximal region
of the northern peninsula of Sulawesi. The previously postulated wide area of integradation between the two species at the
possible contact zone was, however, not recognized, and typical examples oftonkeana orhecki were found to be present on the two sides of a narrow “hybrid” zone which was defined by direct observations. Furthermore,
despite considerable individual variations, we were able to allocate most monkeys to one or other of the species. Each of
ten external characteristics of the members of both species more or less encompassed the individual variations, but may undergo
changes with the development of the monkeys. The mechanisms of reproduction of hybrid monkeys and the maintenance of differences
between the species are discussed. 相似文献
Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is a rare hereditary stroke caused by mutations in NOTCH3 gene. We report the first case of CADASIL in an indigenous Rungus (Kadazan-Dusun) family in Kudat, Sabah, Malaysia confirmed by a R54C (c.160C>T, p.Arg54Cys) mutation in the NOTCH3. This mutation was previously reported in a Caucasian and two Korean cases of CADASIL. We recruited two generations of the affected Rungus family (n = 9) and found a missense mutation (c.160C>T) in exon 2 of NOTCH3 in three siblings. Two of the three siblings had severe white matter abnormalities in their brain MRI (Scheltens score 33 and 50 respectively), one of whom had a young stroke at the age of 38. The remaining sibling, however, did not show any clinical features of CADASIL and had only minimal changes in her brain MRI (Scheltens score 17). This further emphasized the phenotype variability among family members with the same mutation in CADASIL. This is the first reported family with CADASIL in Rungus subtribe of Kadazan-Dusun ethnicity with a known mutation at exon 2 of NOTCH3. The penetrance of this mutation was not complete during the course of this study. 相似文献
As the world population grows, the demand for food increases. Although vegetable oils provide an affordable and rich source
of energy, the supply of vegetable oils available for human consumption is limited by the “fuel vs food” debate. To increase
the nutritional value of vegetable oil, metabolic engineering may be used to produce oil crops of desirable fatty acid composition.
We have isolated and characterized β-ketoacyl ACP-synthase II (KASII) cDNA from a high-oleic acid palm, Jessenia bataua. Jessenia KASII (JbKASII) encodes a 488-amino acid polypeptide that possesses conserved domains that are necessary for condensing activities.
When overexpressed in E. coli, recombinant His-tagged JbKASII was insoluble and non-functional. However, Arabidopsis plants expressing GFP-JbKASII fusions had elevated levels of arachidic acid (C20:0) and erucic acid (C22:1) at the expense of stearic acid (C18:0)
and oleic acid (C18:1). Furthermore, JbKASII failed to complement the Arabidopsis KASII mutant, fab1-2. This suggests that the substrate specificity of JbKASII is similar to that of ketoacyl-CoA synthase (KCS), which preferentially elongates stearic and oleic acids, and not palmitic
acid. Our results suggest that the KCS-like JbKASII may elongate C18:0 and C18:1 to yield C20:0 and C22:1, respectively. JbKASII may, therefore, be an interesting candidate gene for promoting the production of very long chain fatty acids in transgenic
oil crops. 相似文献
The objective of this study was to assess whether and how coping strategies affect the welfare of African catfish Clarias gariepinus housed at low and high densities. Group composition influenced feed intake; re‐active groups (comprised of 100% re‐active fish) had a lower specific growth rate (G) and feed intake and a higher feed conversion ratio (RFC) than pro‐active groups. Furthermore, re‐active groups had a lower energy retention than pro‐active groups. The latter was fully due to differences in feed intake, since energy partitioning (on % total gross energy intake basis) was similar among the group composition treatments. Fish held at high stocking density showed a higher RFC and feeding speed and a lower energy retention and agonistic behaviour. None of the measured variables was influenced by the interaction effect. In mixed groups, G and number of skin lesions seemed to be affected by different behavioural phenotypes at low stocking density, but not at high density. These results indicate that both stocking density and group composition affect physical and behavioural responses of C. gariepinus. Furthermore, physical and behavioural data of individual fish housed in mixed groups suggest that coping strategy affects the fitness of different behavioural phenotypes at low, but not at high, stocking density. 相似文献
Response surface methodology (RSM) based on central composite rotatable design was used to investigate the effects of operating
variable, mainly, pH, weight of biomass, and initial lead ion concentration on the lead adsorption capacity at ambient temperature
using dried cells of Lactobacillius bulgaricus. Using RSM, quadratic polynomial equation was obtained for predicting the percent of lead ion removal. Analysis of variance
showed that the effects of pH and weight of dried biomass were concluded to be the key factors influencing the capacity of
lead ion removal. At pH lower than 2 (high acidic condition) and in alkaline condition, there is no significant biosorption.
The optimum percent of lead ion removal was found at pH of 6.78, biomass concentration of 6.58 g/l and initial lead concentration
36.22 ppm. In this condition, percent of lead ion removal was 86.21%. This study showed RSM effectiveness for modeling of
biosorption process. 相似文献
The present study focused on developing a wild-type actinomycete isolate as a model for a non-pathogenic filamentous producer of biosurfactants. A total of 33 actinomycetes isolates were screened and their extracellular biosurfactants production was evaluated using olive oil as the main substrate. Out of 33 isolates, 32 showed positive results in the oil spreading technique (OST). All isolates showed good emulsification activity (E24) ranging from 84.1 to 95.8%. Based on OST and E24 values, isolate R1 was selected for further investigation in biosurfactant production in an agitated submerged fermentation. Phenotypic and genotypic analyses tentatively identified isolate R1 as a member of the Streptomyces genus. A submerged cultivation of Streptomyces sp. R1 was carried out in a 3-L stirred-tank bioreactor. The influence of impeller tip speed on volumetric oxygen transfer coefficient (kLa), growth, cell morphology and biosurfactant production was observed. It was found that the maximum biosurfactant production, indicated by the lowest surface tension measurement (40.5 ± 0.05 dynes/cm) was obtained at highest kLa value (50.94 h−1) regardless of agitation speed. The partially purified biosurfactant was obtained at a concentration of 7.19 g L−1, characterized as a lipopeptide biosurfactant and was found to be stable over a wide range of temperature (20–121 °C), pH (2–12) and salinity [5–20% (w/v) of NaCl].