Background:Kiwi(Apteryx spp.)are flightless ratites from New Zealand whose numbers and distributions have declined following human arrival.Some of the kiwi species are known to hybridise but the extent of hybridizatio...Background:Kiwi(Apteryx spp.)are flightless ratites from New Zealand whose numbers and distributions have declined following human arrival.Some of the kiwi species are known to hybridise but the extent of hybridization is unknown.Methods:We reviewed hybridisation in kiwi(Apteryx spp.)and present new genetic data examining the extent of hybridisation between Rowi(A.rowi)and Little Spotted Kiwi(A.owenii)at Okarito,the location of the only remaining natural population of the threatened Rowi.We also genetically examined the syntype specimens of A.haastii Potts,1872,collected from near Okarito in the 1870s,which have unusual morphologies.Results:We found evidence of recurrent hybridisation between Rowi and Little Spotted Kiwi over the last 150 years,including one F1 hybrid found in the last 15 years,despite Little Spotted Kiwi’s likely extinction on the mainland in the 1970s.However,we found little evidence of introgression of Little Spotted Kiwi alleles into the extant Rowi popula-tion.The syntype specimens of A.haastii were also found to be hybrids between Little Spotted Kiwi and Rowi.Conclusions:Our genetic analyses indicate that,although we detected multiple instances of hybridisation between Rowi and Little Spotted Kiwi,it does not appear to be an ongoing threat to Rowi.Because the syntype specimens of A.haastii are hybrids and therefore not representative of the prevailing usage of the name for the Great Spotted Kiwi(A.haastii),we resurrect the nomen oblitum A.maxima Sclater and Hochstetter,1861 for the large spotted kiwi species.展开更多
Based on dynamometer test cycles or plain motorway operation, heavy truck hybridisation must be considered as uneconomic if only the kinetic vehicle energy can be recuperated. In mountainous regions, micro hybridizati...Based on dynamometer test cycles or plain motorway operation, heavy truck hybridisation must be considered as uneconomic if only the kinetic vehicle energy can be recuperated. In mountainous regions, micro hybridization by a 48V-belt generator or mild parallel hybridisation by a large high voltage electric drive can result in considerable fuel consumption savings as well as additional benefits for heavy load utility vehicles. Additional electric power and battery size are still critical design parameters as well as critical cost factors considering the limited space and depreciation time as well as the need for maximum payload. Based on vehicle model simulations, this contribution quantifies fuel consumption savings, recuperation energy harvesting and battery requirements for different truck sizes with test cycles based on realistic route topography. The main route topography parameter for the recuperation benefit is the effective incline that integrates all downhill sections that overcompensates the vehicle resistance by tire friction and air resistance. The simulation parameter studies lead to an analytical benefit estimation, based on load cycle parameters like effective velocity, effective incline as well as the vehicle parameters mass, drag coefficient and cross sectional area. Thus, the return on investment can be assessed by an analytic rule of thumb, based on tracked cycles of existing vehicles.展开更多
Dot-blot hybridization was applied in this paper to detect five viruses infecting cucurbitaceous crops, Zuccini yellow mosaic virus （ZYMV）, Watermelon mosaic virus （WMV）, Cucumber mosaic virus （CMV）, Papaya ring...Dot-blot hybridization was applied in this paper to detect five viruses infecting cucurbitaceous crops, Zuccini yellow mosaic virus （ZYMV）, Watermelon mosaic virus （WMV）, Cucumber mosaic virus （CMV）, Papaya ringspot viruswatermelon strain （PRSV-W） and Squash mosaic virus （SqMV）, as a good alternative assay in seed health test and epidemiological and transgenic research. Digoxigenin-labelled cDNA probes of the five viruses were synthesized by PCR with the specific primers and applied in dot-blot hybridization to detect five viruses in crude extraction of the infected leaves. And three SqMV probes of different lengths （0.55, 1.6, and 2.7 kb, respectively） were designed to investigate the effect of hybridization. The results showed that the sensitivity for detecting the crude extraction of infected leaves by ZYMV, WMV, CMV, PRSV-W, and SqMV was down to 1：160, 1：160, 1：320, 1：160, and 1：320, respectively. Three SqMV probes of different length showed no differences on the sensitivity and specificity. The digoxigenin-labelled probes prepared by PCR could be used for accurate and rapid identification of 5 viruses infecting cucurbitaceous crops with good stabilities, sensitivities, specificity, and reproducibilifies.展开更多
Drug sensitivity testing to establish resistance to TB drugs takes many months to arrive at. Public health physicians have difficulties with such an approach due to long wait periods and cannot use it to establish com...Drug sensitivity testing to establish resistance to TB drugs takes many months to arrive at. Public health physicians have difficulties with such an approach due to long wait periods and cannot use it to establish community wide prevalence as a way to understand where resistance may be emerging faster and to limit its spread. The objective of this study was to use the dot-blot hybridization technique in the detection of resistance to rifamycin (RIF) and streptomycin (SM) in South- Western Cameroon and to compare the technique with the routine culture and drug susceptibility testing for detecting resistance in a resource poor country, Cameroon. A hospital-based study was conducted at the Regional hospitals of Buea and Limbe and Tiko Central Clinic. Tuberculosis (TB) patients aged 15 to 50 (mean age: 30.50 ± 8.33 standard deviation) were recruited for the study between December 2006 and April 2007. Cultures from 59 patients were tested for rifampicin and streptomycin sensitivity by the modified proportion method and mutational analysis for rpoB codon 516 and rrs codon 513 was performed by the dot-blot hybridization technique. Of the 59 sputum samples collected (36 were males and 23 were females) came from Buea 19 (32.2%), Limbe 20 (33.9%) and Tiko 20 (33.9%) towns respectively. Amplification for the gene showed that there was (59) 100% amplification with primers used for rpoB genes and 43 (72.9%) amplification with primers used for the rrs gene. Mutational analysis demonstrated that resistance to RIF was common in females (52.1%) than males (41.7%) while 6% of the samples were indeterminate. 12 (20.3%) samples showed phenotypic and genotypic resistance to RIF compared to 34 samples (58.1%) for SM. Phenotypic resistance and genotypic susceptibility were found in 5 (8.5%) RIF and 3 (4.7%) SM compared to phenotypic susceptibility and genotypic resistance that were found in 2 (3.5%) RIF and 3(4.7%) SM. Double mutation on rpoB and rrs genes occurred in 8 (13.6%) DNA samples. Resistance to RIF and SM due to mutations on the rpoB and rrs genes respectively in the SW region was found to be high and comparable to the drug susceptibility testing by 92%, (95% CI: 75.7 - 99.1). The Dot-blot technique will be useful in rapidly assessing the effectiveness of national TB control programs in limiting the spread of resistance strains in Cameroon.展开更多
基金KR was supported by the Allan Wilson Centre for Molecular Ecology and Evolution,the Bank of New Zealand Save the Kiwi Trust,and the New Zealand Department of Conservation.LS was funded by a Rutherford Discovery Fellowship from the Royal Society of New Zealand(contract number RDF-MNZ1201).
文摘Background:Kiwi(Apteryx spp.)are flightless ratites from New Zealand whose numbers and distributions have declined following human arrival.Some of the kiwi species are known to hybridise but the extent of hybridization is unknown.Methods:We reviewed hybridisation in kiwi(Apteryx spp.)and present new genetic data examining the extent of hybridisation between Rowi(A.rowi)and Little Spotted Kiwi(A.owenii)at Okarito,the location of the only remaining natural population of the threatened Rowi.We also genetically examined the syntype specimens of A.haastii Potts,1872,collected from near Okarito in the 1870s,which have unusual morphologies.Results:We found evidence of recurrent hybridisation between Rowi and Little Spotted Kiwi over the last 150 years,including one F1 hybrid found in the last 15 years,despite Little Spotted Kiwi’s likely extinction on the mainland in the 1970s.However,we found little evidence of introgression of Little Spotted Kiwi alleles into the extant Rowi popula-tion.The syntype specimens of A.haastii were also found to be hybrids between Little Spotted Kiwi and Rowi.Conclusions:Our genetic analyses indicate that,although we detected multiple instances of hybridisation between Rowi and Little Spotted Kiwi,it does not appear to be an ongoing threat to Rowi.Because the syntype specimens of A.haastii are hybrids and therefore not representative of the prevailing usage of the name for the Great Spotted Kiwi(A.haastii),we resurrect the nomen oblitum A.maxima Sclater and Hochstetter,1861 for the large spotted kiwi species.
文摘Based on dynamometer test cycles or plain motorway operation, heavy truck hybridisation must be considered as uneconomic if only the kinetic vehicle energy can be recuperated. In mountainous regions, micro hybridization by a 48V-belt generator or mild parallel hybridisation by a large high voltage electric drive can result in considerable fuel consumption savings as well as additional benefits for heavy load utility vehicles. Additional electric power and battery size are still critical design parameters as well as critical cost factors considering the limited space and depreciation time as well as the need for maximum payload. Based on vehicle model simulations, this contribution quantifies fuel consumption savings, recuperation energy harvesting and battery requirements for different truck sizes with test cycles based on realistic route topography. The main route topography parameter for the recuperation benefit is the effective incline that integrates all downhill sections that overcompensates the vehicle resistance by tire friction and air resistance. The simulation parameter studies lead to an analytical benefit estimation, based on load cycle parameters like effective velocity, effective incline as well as the vehicle parameters mass, drag coefficient and cross sectional area. Thus, the return on investment can be assessed by an analytic rule of thumb, based on tracked cycles of existing vehicles.
文摘Dot-blot hybridization was applied in this paper to detect five viruses infecting cucurbitaceous crops, Zuccini yellow mosaic virus （ZYMV）, Watermelon mosaic virus （WMV）, Cucumber mosaic virus （CMV）, Papaya ringspot viruswatermelon strain （PRSV-W） and Squash mosaic virus （SqMV）, as a good alternative assay in seed health test and epidemiological and transgenic research. Digoxigenin-labelled cDNA probes of the five viruses were synthesized by PCR with the specific primers and applied in dot-blot hybridization to detect five viruses in crude extraction of the infected leaves. And three SqMV probes of different lengths （0.55, 1.6, and 2.7 kb, respectively） were designed to investigate the effect of hybridization. The results showed that the sensitivity for detecting the crude extraction of infected leaves by ZYMV, WMV, CMV, PRSV-W, and SqMV was down to 1：160, 1：160, 1：320, 1：160, and 1：320, respectively. Three SqMV probes of different length showed no differences on the sensitivity and specificity. The digoxigenin-labelled probes prepared by PCR could be used for accurate and rapid identification of 5 viruses infecting cucurbitaceous crops with good stabilities, sensitivities, specificity, and reproducibilifies.
文摘Drug sensitivity testing to establish resistance to TB drugs takes many months to arrive at. Public health physicians have difficulties with such an approach due to long wait periods and cannot use it to establish community wide prevalence as a way to understand where resistance may be emerging faster and to limit its spread. The objective of this study was to use the dot-blot hybridization technique in the detection of resistance to rifamycin (RIF) and streptomycin (SM) in South- Western Cameroon and to compare the technique with the routine culture and drug susceptibility testing for detecting resistance in a resource poor country, Cameroon. A hospital-based study was conducted at the Regional hospitals of Buea and Limbe and Tiko Central Clinic. Tuberculosis (TB) patients aged 15 to 50 (mean age: 30.50 ± 8.33 standard deviation) were recruited for the study between December 2006 and April 2007. Cultures from 59 patients were tested for rifampicin and streptomycin sensitivity by the modified proportion method and mutational analysis for rpoB codon 516 and rrs codon 513 was performed by the dot-blot hybridization technique. Of the 59 sputum samples collected (36 were males and 23 were females) came from Buea 19 (32.2%), Limbe 20 (33.9%) and Tiko 20 (33.9%) towns respectively. Amplification for the gene showed that there was (59) 100% amplification with primers used for rpoB genes and 43 (72.9%) amplification with primers used for the rrs gene. Mutational analysis demonstrated that resistance to RIF was common in females (52.1%) than males (41.7%) while 6% of the samples were indeterminate. 12 (20.3%) samples showed phenotypic and genotypic resistance to RIF compared to 34 samples (58.1%) for SM. Phenotypic resistance and genotypic susceptibility were found in 5 (8.5%) RIF and 3 (4.7%) SM compared to phenotypic susceptibility and genotypic resistance that were found in 2 (3.5%) RIF and 3(4.7%) SM. Double mutation on rpoB and rrs genes occurred in 8 (13.6%) DNA samples. Resistance to RIF and SM due to mutations on the rpoB and rrs genes respectively in the SW region was found to be high and comparable to the drug susceptibility testing by 92%, (95% CI: 75.7 - 99.1). The Dot-blot technique will be useful in rapidly assessing the effectiveness of national TB control programs in limiting the spread of resistance strains in Cameroon.
