Tencel纤维与棉混纺纱的开发

为了开发出价格低、性能好的Tencel棉混纺纱线,根据Tencel纤维的特性,通过设置恰当的混纺比,选用成本较低、平均长度为30.35 mm的3级细绒棉与Tencel纤维混纺,采用条混工艺,合理配置各工序工艺参数,成功开发出Tn/CJ 60/40 18.3 tex、14.6 tex混纺纱,总结了提高成纱质量的技术措施.     

Characterization of the histidine mutants of Kluyveromyces lactis

Thirty-eight different histidine mutations of Kluyveromyces lactis were isolated and genetically characterized. All of the mutations were nuclear recessive alleles. They turned out to belong to seven different complementation groups, designated hisA1 to hisA7. Five of these genes have been cloned by in vivo complementation of the Klhis mutations. Their homology to some of the histidine genes of Saccharomyces cerevisiae was confirmed by heterologous complementation. However, one of these KlHIS genes did not complement any mutation in the seven known histidine biosynthetic enzymes encoding genes (his1-his7) of S. cerevisiae.     

Two mutations in Oryzaephilus surinamensis (L.) (Coleoptera: Silvanidae)

Clear eye (c) and dark body colour (d) mutations in Oryzaephilus surinamensis (L.) are described. The c mutation is phenotypically identical to “pearl” (Blackman, 1966), lacking pigment in the compound eyes and also in the larval ocelli and Malpighian tubules. These structures are deeply pigmented in the wild type. The d mutation appears as a blackish-brown coloration of the adult, pupa and larva; the wild type body colour is chestnut brown. Crosses made between clear-eyed and dark insects and also crosses of individuals, showing both mutations, with wild type insects showed that the mutations were characterised by recessive autosomal inheritance and were not linked. There was some evidence that the viability of insects homozygous for both mutations was slightly reduced.     

晒烟品种塘蓬烟抗白粉病基因的等位性测定和序列分析

[背景和目的]广东连江县晒烟品种"塘蓬烟"是我国特有的烟草隐性遗传白粉病抗性种质资源,但到目前为止对其抗病机制未见深入报道.[方法]利用塘蓬烟花粉与抗白粉病烟草品种Kutsaga E1及感病品种K326杂交进行抗病基因的等位性检测;利用等位基因分子标记检测塘蓬烟中感白粉病基因NtMLO1/2的突变情况;利用PCR克隆技...     

The effect of mutations in the insulin-like growth factor-II and ryanodine receptor-1 genes on biochemical and histochemical muscle fibre characteristics in pigs

Mutations in IGF-II (insulin-like growth factor-II) and RYR1 (ryanodine receptor-1) increase lean meat content in pigs but with different effects on meat quality. Differences in biochemical and histochemical muscle fibre characteristics between the two mutations can thus be suspected. Therefore, the aim of this study was to investigate the effect of the IGF-II mutation (Apat vs. Gpat) on biochemical and histochemical muscle fibre characteristics in relation to the RYR1 genotype (Nn vs. NN). A prenatal effect of the IGF-II mutation could not be excluded but the increased leanness in both mutations was clearly related to postnatal muscle hypertrophy due to an increase in muscle fibre diameter and a higher proliferative capacity in animals carrying the IGF-II mutation. No effect of the IGF-II or RYR1 mutation was found on fibre type composition and metabolic enzyme activities. Interactions between IGF-II and RYR1 genotypes suggest that the mechanism involved in increased leanness due to the impaired RYR1 receptor might influence the underlying mechanisms of the IGF-II mutation.     

集聚槽倾角对紧密纱质量的影响

探讨集聚槽倾角对紧密纱质量的影响。分析了紧密纺异形管集聚槽的形态与作用,并采用集聚槽倾角为5°、7°、9°3种不同的异形管,分别纺制5种不同线密度的紧密纱,进行纺纱质量对比试验。结果表明:随着集聚槽倾角的增大,单纱强力降低,有害毛羽数减少;集聚槽倾角的增大对29.2tex和19.4tex纱条干CV值影响规律不明显,但14.6tex、11.7tex与9.7tex纱线的条干CV值则随着集聚槽倾角的增大而升高。     

Quantity/intensity relations in soils and the potassium nutrition of the strawberry plant (Fragaria SP)

In glasshouse pot experiments over two years, the strawberry plant used potassium primarily from sources which were in instantaneous equilibrium with the soil solution. Leaf potassium concentration at flowering and fruiting was highly correlated with the initial equilibrium potassium activity ratio (AR) of the soil, and a linear relationship existed between 1/Leaf-K and 1/AR Yield of fruit was less well correlated with AR than with the quantity of labile potassium in the soil. the gradient of the straight line part of the quantity/intensity (Q/I) graph was increased for 2 of the 5 soils after the period of intensive cropping; this could be related to an increase in the amount of exchangeable calcium+magnesium in the soil.     

A pearl-eyed mutation in Oryzaephilus mercator (Fauv.) (Coleoptera,Silvanidae)

A pearl-eyed mutation in Oryzaephilus mercator (Fauv.) was observed in a culture of a strain obtained from a cargo of desiccated coconut imported into the U.K. in 1978. The mutation appears as an unpigmented compound eye bordered by an apparently pigmented region which is probably caused by the pigment of the underlying ocular diaphragm showing through the eye. The ocelli and Malpighian tubules of mutant larvae also lack pigment; in wild-type larvae these structures are deeply pigmented. Crosses between pearl-eye and wild-type beetles showed that in O. mercator the mutation is inherited as a sex-linked recessive gene. Observations on other pearl-eye mutants showed that although a number of phenotypic characters are similar there are, nevertheless, phenotypic differences and differences in the pattern of inheritance between them. It is possible that we may be observing parallel phenotypic effects from non-homologous mutations.     

Effect of root zone pH and form and concentration of nitrogen on accumulation of quality‐related components in green tea

Green tea quality is greatly influenced by concentrations of free amino acids, polyphenols (mainly catechins) and caffeine. The present study investigated the principal relationship between selected nutritional factors (form and concentration of N supply, root zone pH) and accumulation of these quality‐related components of tea (Camellia sinensis (L.)) plants. Tea plants were hydroponically cultured with NH , NO and NH NO at pH 4.0, 5.0 and 6.0 in one experiment and supplied with varying N concentrations (0.75, 2.0 and 4.5 mmol L^?1, NH /NO^?₃ = 3:1) in another experiment. Concentrations of free amino acids were considerably higher in NH ‐ than in NO ‐fed plants. This was attributed to the much greater absorption of NH compared with NO . Furthermore, the relative allocation of absorbed N to free amino acids, particularly theanine and glutamine, was substantially increased by NH nutrition, suggesting that NH was more readily assimilated than NO into theanine. The concentration of caffeine was increased in NH ‐ and (NH NO )‐supplied plants, whereas concentrations of catechins were reduced in (NH NO )‐fed plants. Root zone pH did not influence concentrations of most free amino acids in young shoots, with the exception of theanine, which increased at low pH (4.0) irrespective of N form; this likely stemmed from an accumulation effect, as growth decreased more strongly than N absorption. Raising the N supply increased plant N allocation to free amino acids. The increase was most striking for arginine, while theanine was only marginally affected. This may have adverse consequences for green tea quality, as less favourable taste characteristics have been attributed to arginine. Copyright © 2007 Society of Chemical Industry     

The extraction of radiolabelled inorganic sulphate from blood plasma

A study was conducted into factors governing the efficiency of the ion exchange method for extracting ³⁵S-labelled inorganic sulphate (SO) from blood plasma, using Dowex′1-X8 ion exchange resin. The study compared effects of trichloroacetic acid (TCA) strength as protein precipitant, different HCl strengths as resin eluent, sodium citrate/HCl (SC/HCl) versus HCl as eluents, and evaluated ultrafiltrated (UF) plasma upon the adsorption and recovery of added ³⁵SO. Both adsorption and release of ³⁵SO from the resin were inhibited by the presence of TCA, and HCl was not as effective as 1 M SC/2 M HCl in releasing ³⁵SO adsorbed to resin. The rates of ³⁵SO adsorbed onto resin and recovered were markedly increased by using UF plasma and 1 M SC/2 M HCl as eluent, with the values being 96.3 ± 0.11% and 91.1 ± 0.39%, respectively, where 1 g resin was used. Therefore, the use of UF for deproteinising and 1 M SC/2M HCl as eluent are recommended for extracting ³⁵SO from blood plasma when Dowex′1-X8 resin is used as the ion exchanger.     

Glucan structure in a fragile mutant of Saccharomyces cerevisiae

The phenotype of VY1160 fragile Saccharomyces cerevisiae mutant is characterized by cell lysis upon transfer to hypotonic solutions and increased permeability of cells growing in osmotically stabilized media. Two mutations, srb1 and ts1, have been identified in VY1160 cells and previous studies have shown that the increased permeability is due to the ts1 mutation which causes a shortening of mannan side-chains. Here we report that the srb1 mutation, which is the genetic determinant of cell lysis, is responsible for quantitative and structural changes of glucans. Experiments with isogenic single mutation strains, genetic studies coupled with quantitative measurements of glucan content per cell, and methylation analysis of glucans provide evidence that srb1 mutation leads to i) formation of mechanically unstable cell wall network made of insoluble glucan fibrils which are shorter and contain beta(1-6) inter-residue linkages and ii) insufficient filling of the space between the fibrils due to a shortage of the alkali-soluble glucan. Although growing exponentially in osmotically stabilized media, the srb1 cells cannot resist an osmotic shock and, hence, burst immediately.     

The relative merits of the presence of hull on the nutritional qualities of the African yam bean flour

The flour from three colour cultivars of hulled and dehulled seeds of the African yam bean (AYB) (Sphenostylis stenocarpa) was analysed for anatomical fractions; proximate, mineral, fatty and amino acids composition. The seed hull varied between 8.25% and 9.14%. Na, K. Ca, Mn, Fe, Zn are preferably found in the hulled samples. Essential fatty acids as well as essential amino acids are more enriched in the hulled samples than in the endosperm. Correlation coefficient results showed that proximate composition (r, r, r), mineral composition (r, r, r), fatty acids (r, r, r), fatty acids saturation (r, r, r) and amino acids (r, r, r) were significant at α = 0.05 in the samples shown in parentheses with values having high positive correlation coefficients ranging from 0.82 to 1.00. These results showed that dehulling of African yam bean seeds will lead to reduction in the nutritional qualities of the AYB.     

Newly identified mutations at the CSN1S1 gene in Ethiopian goats affect casein content and coagulation properties of their milk

Very high casein content and good coagulation properties previously observed in some Ethiopian goat breeds led to investigating the α_s1-casein (CSN1S1) gene in these breeds. Selected regions of the CSN1S1 gene were sequenced in 115 goats from 5 breeds (2 indigenous: Arsi-Bale and Somali, 1 exotic: Boer, and 2 crossbreeds: Boer × Arsi-Bale and Boer × Somali). The DNA analysis resulted in 35 new mutations: 3 in exons, 3 in the 5′ untranslated region (UTR), and 29 in the introns. The mutations in exons that resulted in an amino acid shift were then picked to evaluate their influence on individual casein content (α_s1-, α_s2-, β-, and κ-CN), micellar size, and coagulation properties in the milk from the 5 goat breeds. A mutation at nucleotide 10657 (exon 10) involved a transversion: CAG→CCG, resulting in an amino acid exchange Gln₇₇→Pro_77. This mutation was associated with the indigenous breeds only. Two new mutations, at nucleotide 6072 (exon 4) and 12165 (exon 12), revealed synonymous transitions: GTC→GTT in Val₁₅ and AGA→AGG in Arg₁₀₀ of the mature protein. Transitions G→A and C→T at nucleotides 1374 and 1866, respectively, occurred in the 5′ UTR, whereas the third mutation involved a transversion T→G at nucleotide location 1592. The goats were grouped into homozygote new (CC), homozygote reference (AA), and heterozygote (CA) based on the nucleotide that involved the transversion. The content of α_s1-CN (15.32 g/kg) in milk samples of goats homozygous (CC) for this newly identified mutation, Gln₇₇→Pro₇₇ was significantly higher than in milks of heterozygous (CA; 9.05 g/kg) and reference (AA; 7.61 g/kg) genotype animals. The α_s2-, β-, and κ-CN contents showed a similar pattern. Milk from goats with a homozygous new mutation had significantly lower micellar size. Milk from both homozygote and heterozygote new-mutation goats had significantly shorter coagulation rate and stronger gel than the reference genotype. Except the transversion, the sequence corresponded to allele A and presumably derived from it. Therefore, this allele is denoted by A₃. All goats from the reference genotype (AA) were homozygous for the allele at nucleotide position 1374 and 1866, whereas all mutations in the 5′ UTR existed in a heterozygous form in both heterozygous (CA) and the new mutation (CC) genotype. The newly identified mutation (CC) detected in some of the goat breeds is, therefore, important in selection for genetic improvement and high-quality milk for the emerging goat cheese-producing industries. The finding will also benefit farmers raising these goat breeds due to the increased selling price of goats. Further studies should investigate the effect of this amino acid exchange on the secondary and tertiary structure of the α_s1-CN molecule and on the susceptibility of peptide hydrolysis by digestive enzymes.     

Intrinsic viscosities and apparent specific volumes of amino acids and sugars. ‘Effective size’ and taste of sapid molecules

Intrinsic viscosities ([η]) and apparent specijic volumes (V) are compared for a number of amino acids and simple sugars and their derivatives. While the sugars and their derivatives fit within a narrow range for both parametevs ([η])=2.27–2.61 cm³ g^?1; V=0.60–4.69 cm³ g^?1), the amino acids cover a much wider band ([η]) = 1.29–4.20 cm³ g^?1; V=0.562–0.712 cm³ g^?1). The intrinsic viscosity value of any particular amino acid is always greater than the corresponding apparent specijc volume, and ranges (at 10 mg g^?1) between two and seven times the value of the apparent specific volume. For the sugars and sugar derivatives, on the other hand, the intrinsic viscosities are always three to four times greater than the values of the corresponding apparent specijic volumes. When concentration is increased, all apparent specific volumes increase but they remain relatively constant if they are expressed as parachors (Vγ^1/4). Differences between the sugars and amino acids originate in the greater structural diversification of the latter molecules which in turn accords with their greater range of taste qualities.     

UVS112—A gene involved in excision repair of yeast

In this study we show that the previously described uvs112 (uvs12) mutation blocks one of the steps of the excision repair pathway. The properties of this mutation permit the assignment of the UVS112 gene to the RAD3 epistasis group. It was established that the uvs112 mutation caused a 2·5-fold reduction in the number of recombinants produced by conversion and also significantly increased the frequency of mitotic crossing-over in interplasmid recombination. Tetrad analysis placed the UVS112 gene on the left arm of chromosome IX, approximately 20 cM from HIS5. The analysis of mitotic recombination revealed that UVS112 lies between HIS6 and HIS5, and is an allele of the RAD25 gene.     

Implication of Complex Vertebral Malformation and Bovine Leukocyte Adhesion Deficiency DNA-Based Testing on Disease Frequency in the Holstein Population

Two inherited lethal disorders, bovine leukocyte adhesion deficiency (BLAD) and complex vertebral malformation (CVM), play a major role in breeding of Holstein cattle. Both inherited diseases are based on single nucleotide polymorphisms that have been known for 12 and 7 yr, respectively. A total of 25,753 cattle were genotyped for BLAD (18,200 tests) and CVM (14,493 tests) in our laboratory since the beginning of the genotyping programs for these diseases. Based on founder effects, the CVM mutation is thought to be linked to milk production. The BLAD was genotyped using RFLP until 2001; then a fluorescence resonance energy transfer assay on a LightCycler was used, as for CVM genotyping. By using single nucleotide polymorphism-aided breeding, the allelic frequency of the BLAD and CVM mutations in the active sire population was reduced from 9.4% in 1997 to 0.3% in 2007 (BLAD) and from 8.3% in 2002 to 2.3% in 2007 (CVM), with calculated half-life of the mutant allele of 2.1 yr for BLAD and 3.6 yr for CVM. An observed increase of BLAD frequency in 1999 could be attributed to the massive use of a BLAD-positive sire tested falsely negative in another laboratory. These data show that marker-assisted selection is capable of substantially reducing the frequency of a mutation within a period of not more than 5 yr. The different selection strategies against the lethal recessive allele in CVM and BLAD are reflected in the different reduction rates of the specific allele frequencies.     

Relationship of thermal status to productivity in heat-stressed dairy cows given recombinant bovine somatotropin

The responses of lactating Holstein cows to daily administration of bovine somatotropin (bST) were measured at thermoneutrality (Tn) and under both constant and cycled heat-stress conditions to determine the relationship between thermal status and bST-induced shifts in milk production. All tests included a 5-d acclimation period at Tn (18°C), followed by a 2-d increase in ambient temperature to 28.5°C. After d 3, ambient temperature was cycled between 28.5 (day) and 25.5°C (night) for 4 d. Daily injections with either 31 mg of bST or saline began on d 1 of the experiment. Milk production, feed intake, and respiratory rate (RR) were measured daily. Intraperitoneal, telemetric temperature transmitters were used for a continuous measure of core body temperature (T_core). Blood samples were collected during each phase to evaluate the changes in serum chemistry in response to bST and heat stress. Following a 15-d recovery, cows were switched across injection treatments and the study was repeated. Milk production decreased by ∼18.4% below the initial yield at Tn by the end of 7 d of heat challenge. Although a reduction in milk production occurred during heat stress in both groups, milk production was higher in bST-treated cows compared with control cows during periods of constant and cyclic heat. Likewise, bST treatment during the entire period increased the milk-to-feed ratio over the control level by ∼11.3%. Plasma insulin-like growth factor 1 and serum nonesterified fatty acids accompanied the increased growth hormone level with bST treatment (∼122.0 and 88.8%, respectively), whereas plasma urea nitrogen was reduced by ∼13.3% to reflect the shift to lipid metabolism. There was no difference in T_core of the treatment and control groups at Tn. Both bST and control cows increased RR and T_core above the Tn level by ∼94.8 and 2.9%, respectively, during constant heat, with a greater increase in T_core of bST-treated compared with control cows (∼0.6%). The increase in RR during heat stress preceded T_core by 1 d for both groups. During cyclic heat, T_core decreased by ∼0.4% compared with constant heat in both the control and bST-treated groups. Bovine somatotropin treatment increased milk production similarly during the Tn and heat-stress periods, ∼8.3% over the control; however, the bST-induced increase in milk-to-feed ratio was greatest during the continuous and cyclic heat-stress phases, ∼16.2%. This increase occurred together with the elevation in T_core.     

EXTRACELLULAR PROTEASE ACTIVITY IN A STRAIN OF SACCHAROMYCES CEREVISIAE

The isolation and analysis of a strain of laboratory yeast with extracellular protease activity is described. The proteolytic activity found in culture supernatants exceeded the parental strain by at least an order of magnitude and apparently was due neither to cell lysis nor to increased cell wall permeability. The extracellular proteases were heterogeneous in composition, consisting of possibly 3 aberrantly secreted intracellular proteinases. This extracellular protease activity was conferred by a single recessive mutation (epr1.1) in a gene displaying classical Mendelian inheritance. EPR1 was tentatively assigned to chromosome XV with loose linkage to the HIS3 gene. Strains carrying the mutant epr1.1) allele also possessed increased levels of secreted invertase activity and it is proposed that EPR1 is closely involved in the intracellular protein translocation pathway of yeast.