Refined mapping of the Pierce's disease resistance locus, PdR1, and Sex on an extended genetic map of Vitis rupestris x V. arizonica

A framework genetic map based on genomic DNA-derived SSR, EST-derived SSR, EST-STS and EST-RFLP markers was developed using 181 genotypes generated from D8909-15 (female) x F8909-17 (male), the '9621' population. Both parents are half siblings with a common female parent, Vitis rupestris 'A. de Serres', and different male parents (forms of V. arizonica). A total of 542 markers were tested, and 237 of them were polymorphic for the female and male parents. The female map was developed with 159 mapped markers covering 865.0 cM with an average marker distance of 5.4 cM in 18 linkage groups. The male map was constructed with 158 mapped molecular markers covering 1055.0 cM with an average distance of 6.7 cM in 19 linkage groups. The consensus '9621' map covered 1154.0 cM with 210 mapped molecular markers in 19 linkage groups, with average distance of 5.5 cM. Ninety-four of the 210 markers on the consensus map were new. The 'Sex' expression locus segregated as single major gene was mapped to linkage group 2 on the consensus and the male map. PdR1, a major gene for resistance to Pierce's disease, caused by the bacterium Xylella fastidiosa, was mapped to the linkage group 14 between markers VMCNg3h8 and VVIN64, located 4.3 and 2.7 cM away from PdR1, respectively. Differences in segregation distortion of markers were also compared between parents, and three clusters of skewed markers were observed on linkage groups 6, 7 and 14.

Gastro-ileal stenosis and gastroparesis after a biliopancreatic diversion

Biliopancreatic diversion (BPD) is a very effective bariatric operation particularly for super-obese patients (BMI > or = 50 kg/m(2)). We present the development of a stricture at the gastro-ileal anastomotic site, with subsequent dilatation and aperistalsis of the stomach in a female patient who had undergone a standard open Scopinaro BPD. The patient remained symptomatic and persisted in losing weight, despite endoscopic balloon dilatations of the stricture and surgical revision of the anastomosis. She finally underwent conversion to a standard Roux-en-Y proximal gastric bypass. We describe the development of the stricture after the use of the stapling gun, subsequent gastric dilatation and dysmotility.

Can WHO therapy failure criteria for non-severe pneumonia be improved in children aged 2-59 months?

SETTING

In the recent past, there have been reports of rising treatment failure rates for non-severe pneumonia. It is felt that World Health Organization (WHO) criteria for therapy failure are too sensitive and that many children are unnecessarily classified as failures. We studied alternative, less sensitive therapy failure criteria.

METHODS

In this nested study we followed the clinical course of non-severe pneumonia in children aged 2-59 months using alternative therapy failure criteria. All children received amoxicillin and were followed up on days 3, 5 and 14 after enrollment. On day 3, children were labelled as therapy failure only if their condition had deteriorated. These failure rates were compared with those using WHO definitions.

RESULTS

During the study period, 876 children with non-severe pneumonia were followed up until day 14. On day 3, using alternative therapy failure criteria, 31 (3.5%) children were labelled as therapy failure compared to 95 (10.8%) using current WHO criteria. The difference was statistically significant (P = 0.001).

CONCLUSIONS

The alternative therapy failure criteria work reasonably well, without causing any higher risk to children with non-severe pneumonia. Antibiotics should be changed only in those children who show signs of deterioration on day 3. This would prevent unnecessary changes in antibiotic treatment in many children.

An integrated SSR map of grapevine based on five mapping populations

A grapevine (mainly Vitis vinifera L., 2n = 38) composite genetic map was constructed with CarthaGene using segregation data from five full-sib populations of 46, 95, 114, 139 and 153 individuals, to determine the relative position of a large set of molecular markers. This consensus map comprised 515 loci (502 SSRs and 13 other type PCR-based markers), amplified using 439 primer pairs (426 SSRs and 13 others) with 50.1% common markers shared by at least two crosses. Out of all loci, 257, 85, 74, 69 and 30 were mapped in 1, 2, 3, 4 and 5 individual mapping populations, respectively. Marker order was generally well conserved between maps of individual populations, with only a few significant differences in the recombination rate of marker pairs between two or more populations. The total length of the integrated map was 1,647 cM Kosambi covering 19 linkage groups, with a mean distance between neighbour loci of 3.3 cM. A framework-integrated map was also built, with marker order supported by a LOD of 2.0. It included 257 loci spanning 1,485 cM Kosambi with a mean inter-locus distance of 6.2 cM over 19 linkage groups. These integrated maps are the most comprehensive SSR-based maps available so far in grapevine and will serve either for choosing markers evenly scattered over the whole genome or for selecting markers that cover particular regions of interest. The framework map is also a useful starting point for the integration of the V. vinifera physical and genetic maps.

Identification and molecular mapping of PdR1, a primary resistance gene to Pierce's disease in Vitis

A major quantitative trait locus (QTL) controlling resistance to Pierce's disease (PD) of grape, caused by the bacterium Xylella fastidiosa (Xf), was identified on a Vitis linkage map and denoted as 'Pierce's disease resistance 1' (PdR1). Placement of the locus was accomplished by evaluating a family of full-sib progeny from a cross of two PD-resistant interspecific hybrids with resistance inherited from Vitis arizonica. Resistance was measured under greenhouse conditions by direct quantification of Xf numbers in stem tissues as well as by evaluation of disease symptoms based on leaf scorch and a cane maturation index (CMI). A large QTL (LOD 17.2) accounting for 72% of the phenotypic variance in bacterial numbers was localized to linkage group 14 of the male parent F8909-17. The approximate 95% confidence interval around the QTL peak extended 5.7 cM when using composite interval mapping. The other disease evaluation methods (leaf scorch and CMI, respectively) placed the resistance QTL to the same region on linkage group 14, although at wider 95% confidence intervals (6.0 and 7.5 cM), lower peak LOD scores (11.9 and 7.7) and accounting for less phenotypic variance (59 and 42%). This is the first report of an Xf resistance QTL mapped in any crop species. The relevance of the markers located in the region spanning the QTL will be discussed, addressing their usefulness for the development of PD-resistant grape cultivars.

A genetic linkage map of grape, utilizing Vitis rupestris and Vitis arizonica

A genetic linkage map of grape was constructed, utilizing 116 progeny derived from a cross of two Vitis rupestris x V. arizonica interspecific hybrids, using the pseudo-testcross strategy. A total of 475 DNA markers-410 amplified fragment length polymorphism, 24 inter-simple sequence repeat, 32 random amplified polymorphic DNA, and nine simple sequence repeat markers-were used to construct the parental maps. Markers segregating 1:1 were used to construct parental framework maps with confidence levels >90% with the Plant Genome Research Initiative mapping program. In the maternal (D8909-15) map, 105 framework markers and 55 accessory markers were ordered in 17 linkage groups (756 cM). The paternal (F8909-17) map had 111 framework markers and 33 accessory markers ordered in 19 linkage groups (1,082 cM). One hundred eighty-one markers segregating 3:1 were used to connect the two parental maps' parents. This moderately dense map will be useful for the initial mapping of genes and/or QTL for resistance to the dagger nematode, Xiphinema index, and Xylella fastidiosa, the bacterial causal agent of Pierce's disease.

A microsatellite marker based framework linkage map of Vitis vinifera L

We have constructed a framework linkage map based on microsatellite markers for Vitis vinifera L., the European wine grape. The mapping population consisted of 153 progeny plants from a cross of Vitis vinifera cvs. Riesling x Cabernet Sauvignon. One hundred fifty-two microsatellite markers and one polymorphic EST marker have been mapped to 20 linkage groups (2 n=38). The map covers 1,728 cM with an average distance between markers of 11.0 cM. Estimates of genome size, expected genome coverage, and observed genome coverage were determined with 135-140 markers. Genome length estimates differed between paternal and maternal data sets. Observed approximate genome coverage was 65% versus an expected coverage of 90%. Meiotic recombination rates were not significantly different between maternal and paternal parents. This map has been adopted as a reference map for the International Grape Genome Program.

Genetic mapping of grapevine ( Vitis vinifera L.) applied to the detection of QTLs for seedlessness and berry weight

Parental and consensus genetic maps of Vitis vinifera L. (2n = 38) were constructed using a F(1) progeny of 139 individuals from a cross between two partially seedless genotypes. The consensus map contained 301 markers [250 amplification fragment length polymorphisms (AFLPs), 44 simple sequence repeats (SSRs), three isozymes, two random amplified polymorphic DNAs (RAPDs), one sequence-characterized amplified region (SCAR), and one phenotypic marker, berry color] mapped onto 20 linkage groups, and covered 1,002 cM. The maternal map consisted of 157 markers covering 767 cM (22 groups). The paternal map consisted of 144 markers covering 816 cM (23 groups). Differences in recombination rates between these maps and another unpublished map are discussed. The major gene for berry color was mapped on both the paternal and consensus maps. Quantitative trait loci (QTLs) for several quantitative subtraits of seedlessness in 3 successive years were searched for, based on parental maps: berry weight, seed number, seed total fresh and dry weights, seed percent dry matter, and seed mean fresh and dry weights. QTLs with large effects (R(2) up to 51%) were detected for all traits and years at the same location on one linkage group, with some evidence for the existence of a second linked major QTL for some of them. For these major QTLs, differences in relative parental effects were observed between traits. Three QTLs with small effects (R(2) from 6% to 11%) were also found on three other linkage groups, for berry weight and seed number in a single year, and for seed dry matter in 2 different years.

Skeletal muscle myosin heavy chain isoforms and energy metabolism after clenbuterol treatment in the rat

Prolonged treatment with the beta(2)-adrenoceptor agonist clenbuterol (1-2 mg. kg body mass(-1). day (-1)) is known to induce the hypertrophy of fast-contracting fibers and the conversion of slow- to fast-contracting fibers. We investigated the effects of administering a lower dose of clenbuterol (250 microgram. kg body mass(-1). day (-1)) on skeletal muscle myosin heavy chain (MyHC) protein isoform content and adenine nucleotide (ATP, ADP, and AMP) concentrations. Male Wistar rats were administered clenbuterol (n = 8) or saline (n = 6) subcutaneously for 8 wk, after which the extensor digitorum longus (EDL) and soleus muscles were removed. We demonstrated an increase of type IIa MyHC protein content in the soleus from approximately 0.5% in controls to approximately 18% after clenbuterol treatment (P < 0.05), which was accompanied by an increase in the total adenine nucleotide pool (TAN; approximately 19%, P < 0.05) and energy charge [E-C = (ATP + 0.5 ADP)/(ATP + ADP + AMP); approximately 4%; P < 0.05]. In the EDL, a reduction in the content of the less prevalent type I MyHC protein from approximately 3% in controls to 0% after clenbuterol treatment (P < 0.05) occurred without any alterations in TAN and E-C. These findings demonstrate that the phenotypic changes previously observed in slow muscle after clenbuterol administration at 1-2 mg. kg body mass(-1). day(-1) are also observed at a substantially lower dose and are paralleled by concomitant changes in cellular energy metabolism.

A vitamin D(3) derivative (CB1093) induces nerve growth factor and prevents neurotrophic deficits in streptozotocin-diabetic rats

AIMS/HYPOTHESIS

Streptozotocin-diabetic rats show impaired neurotrophic support by deficient nerve growth factor (NGF) in muscle and skin. We, therefore, examined a novel agent (CB1093; 1(S), 3(R)-Dihydroxy-20(R)-(1-ethoxy-5-ethyl-5-hydroxy-2-heptyn-1-yl)-9, 10-seco-pregna-5(Z),7(E),10(19)-triene), which induces expression of endogenous nerve growth factor.

METHODS

We gave CB1093 orally followed by measurements of mechanical nociception, nerve growth factor, neuropeptides (immunoassay) and nerve growth factor receptors (western blots).

RESULTS

In non-diabetic rats CB1093 caused dose-dependent increases in nerve growth factor production (140 % in soleus muscle and 190 % in sciatic nerve) and a mechanical hyperalgesia in the foot. There was also increased sciatic nerve expression of neuronal NGF target gene products, substance P (16 %) and calcitonin gene-related peptide (CGRP; 52 %). Depletions of nerve growth factor, substance P and CGRP in sciatic nerves of diabetic rats were prevented by CB1093, which also increased soleus nerve growth factor concentrations to 30 % over those seen in non-diabetic rats and increased its mRNA expression in skin. The CB1093 did not affect expression of nerve growth factor receptors (trkA and p75(NTR)) in dorsal root ganglia in control or diabetic rats, though the p75(NTR) expression was reduced by diabetes. The mechanical hyperalgesia seen in diabetic rats treated with vehicle was not exacerbated by CB1093.

CONCLUSION/INTERPRETATION

These findings show that in animal models of diabetes it is possible to prevent depletions of nerve growth factor and the products of its neuronal target genes by oral treatment of a highly potent inducer of NGF gene expression. Pain is a possible side-effect, though this was a function of dose and was manifest more in controls than in diabetic rats. [Diabetologia (1999) 42: 1308-1313]

Diagnostic problems in multiple sclerosis: overreliance on neuroimaging

Atypical manifestations of multiple sclerosis (MS) can mislead the physician into misdiagnosis. The correct diagnosis of MS depends on a combination of clinical and laboratory evidence. The introduction of newer neuroimaging studies has decreased the proportion of overdiagnoses of MS. Overreliance on either clinical or laboratory (currently neuroimaging) data can lead to underdiagnosis. The physician should consider the possibility of an atypical clinical presentation of MS in the differential diagnosis of patients with disease of the central nervous system.