Development of a method for the identification, using the polymerase chain reaction, of Aspergillus fumigatus isolated from ostriches

Objective To develop a method for identifying DNA of Aspergillus fumigatus from ostriches, using the polymerase chain reaction (PCR). A fumigatus is the principal causative agent of avian aspergillosis.
Design A biochemical trial.
Sample population Twelve Aspergillus fumigatus isolates and three other Aspergillus species.
Procedure PCR primers that were based on the sequence of the alkaline protease gene from human isolates of A fumigatus were used.
Results We successfully tested the method on ostrich isolates from five states and showed that the test is specific for A fumigatus.
Conclusions In most cases the DNA sequence of A fumigatus isolates from ostriches is similar to that of human isolates. DNA sequences vary significantly among A fumigatus isolates, including those from affected ostriches in the same flock. The genetic variation may be used to trace aspergillus infections in ostrich flocks and determine if the disease is transmitted by contact with infected birds.     

山羊乳镉向乳产品的转移

通过对3只泌乳山羊连续服用镉,研究了镉从全乳向乳产品的转移。试验羊摄入镉之前,乳镉浓度为<0.2～0.2μg/L,摄入镉期间,乳镉浓度为1.2～4.6μg/L,在奶油中镉的浓度是原始乳镉的3.1±0.7倍,在用酸化法和加酶法制作的奶酪中的镉分别是原始乳镉的3.3±0.3倍和5.7±0.7倍。原始乳中的镉,大约25％分布在奶油中(23.9±5.4％),大约60％分布在奶酪中(61.6±5.4％分布在用加酶法制作的奶酪中,56.8±4.8％分布在用酸化法制作的奶酪中),分布在两种乳清中的镉分别为12.9±2.8％和16.3±5.3％。从原始乳向全部乳产品转移的镉为99.2～100.4％。     

Microglial activation resulting from CD40-CD40L interaction after beta-amyloid stimulation

Alzheimer's disease (AD) has a substantial inflammatory component, and activated microglia may play a central role in neuronal degeneration. CD40 expression was increased on cultured microglia treated with freshly solublized amyloid-beta (Abeta, 500 nanomolar) and on microglia from a transgenic murine model of AD (Tg APPsw). Increased tumor necrosis factor alpha production and induction of neuronal injury occurred when Abeta-stimulated microglia were treated with CD40 ligand (CD40L). Microglia from Tg APPsw mice deficient for CD40L demonstrated reduction in activation, suggesting that the CD40-CD40L interaction is necessary for Abeta-induced microglial activation. Finally, abnormal tau phosphorylation was reduced in Tg APPsw animals deficient for CD40L, suggesting that the CD40-CD40L interaction is an early event in AD pathogenesis.     

Multiple allelism at a major locus affecting fruit coloration in Cucurbita pepo

The l-2 (light coloration-2) locus in Cucurbita pepo (pumpkin, squash, gourd) has a major effect on fruit color intensity through its complementary interactions with at least three other loci. From a sixth-generation backcross progeny of which a wild gourd having striped fruits was the donor parent and a cultigen having ‘plain light’-colored fruits(genotype l-2/l-2) was the recurrent parent, a true-breeding line was isolated that had a fruit color phenotype that differed from both parents. The fruits of this line were not striped and had a color pattern resembling‘light type 2’ (genotype L-2/–-), but of weaker expression. This newly established line was then crossed with near-isogenic lines of genotypes l-2/l-2 and L-2/L-2 and the resulting filial and backcross progenies were observed under field conditions. The results indicated that the new phenotype is recessive to ‘light type 2’ but dominant to ‘plain light’ and that it is conferred by a single gene. The results of a testcross for allelism indicated that this gene is an allele at the l-2 locus and it is herein designated L-2 ^w. Dominance relationships at the l-2 locus are L-2 > L-2 ^w >l-2. This revised version was published online in July 2006 with corrections to the Cover Date.     

Advances in pasture plant breeding for animal productivity and health

Plant breeding has had a substantial effect on the productivity and health of ruminant animals in New Zealand by improving the quantity, quality and reliability of grazed temperate pastures. Genetic changes have affected annual pasture productivity, seasonal growth, digestibility, protein/energy balance, level of rumen undegradable protein, leaf properties affecting intake, resistance to foliar diseases, and reductions in compounds that have an adverse impact on the health, welfare and reproductive fertility of ruminant animals. Most plant improvement programmes have achieved genetic gains in excess of 1% per year for a variety of target traits, and these gains are likely to continue given the high genetic variation available within forage plants. Significant heritable variation exists to improve forage quality, particularly for soluble carbohydrate and fibre fractions in grasses, and in the rate at which these change during the season. Deleterious animal health and welfare effects can be alleviated through the use of non-toxic endophytes in grasses, that do not produce lolitrem B and ergovaline. Use of improved cultivars, with the appropriate management, can add value to animal products.     

Blue-light-activated histidine kinases: two-component sensors in bacteria

Histidine kinases, used for environmental sensing by bacterial two-component systems, are involved in regulation of bacterial gene expression, chemotaxis, phototaxis, and virulence. Flavin-containing domains function as light-sensory modules in plant and algal phototropins and in fungal blue-light receptors. We have discovered that the prokaryotes Brucella melitensis, Brucella abortus, Erythrobacter litoralis, and Pseudomonas syringae contain light-activated histidine kinases that bind a flavin chromophore and undergo photochemistry indicative of cysteinyl-flavin adduct formation. Infection of macrophages by B. abortus was stimulated by light in the wild type but was limited in photochemically inactive and null mutants, indicating that the flavin-containing histidine kinase functions as a photoreceptor regulating B. abortus virulence.     

Minimal External Masculinization in a SRY-negative XX Male Podenco Dog

Normal mammalian sex differentiation takes place in three genetically controlled steps: chromosomal sex determination (XX or XY), gonadal differentiation and development of the phenotypic sex. Animals are considered to be sex reversed if chromosomal sex determination and gonadal development are not in agreement. In this report, sex reversal is described in a 1.5-year-old Podenco dog that was referred because of suspected recurrent growth of a previously removed os clitoridis in the vulva. With that exception the dog was phenotypically female, but had never been in oestrus and exhibited male behaviour. Abdominal ultrasonography showed a small tubular structure dorsal to the bladder, consistent with a uterus. An ovoid structure resembling a gonad was visible between the right kidney and inguinal canal. Plasma testosterone concentrations before and after GnRH administration indicated the presence of functional testicular tissue. Two testes, each with its epididymis and ductus deferens, and a complete bicornuate uterus were removed surgically. Cytogenetic analysis of peripheral blood lymphocytes showed a normal female karyotype (78, XX). These findings are consistent with the diagnosis of an XX male. PCR analysis of genomic DNA revealed that the SRY gene was absent. In summary, this report describes the first SRY-negative XX male Podenco dog with an almost complete female phenotype despite high basal and stimulated plasma testosterone concentrations. It is hypothesized that the clinical observations in this dog may have been caused by reduced and delayed Müllerian-inhibiting substance secretion and the absence of conversion of testosterone to dihydrotestosterone due to 5α-reductase deficiency.