Molecular systematics of Solanum section Lycopersicum (Lycopersicon) using the nuclear ITS rDNA region

The phylogenetic relationships of all nine known tomato species of Solanum section Lycopersicum, together with other Solanum sections and species from several related genera, were investigated using parsimony analysis of the internal transcribed spacer (ITS) region of nuclear ribosomal DNA (rDNA). Most parsimonious reconstructions divided the section Lycopersicum into three clades, reflecting their mating behaviour and fruit colour. Data from sequencing studies were congruent with those from morphological and other molecular investigations, and provided detailed information concerning species relationships. Received: 11 July 2000 / Accepted: 17 April 2001     

A meta-analysis of elevated [CO2] effects on soybean (Glycine max) physiology, growth and yield

The effects of elevated [CO₂] on 25 variables describing soybean physiology, growth and yield are reviewed using meta‐analytic techniques. This is the first meta‐analysis to our knowledge performed on a single crop species and summarizes the effects of 111 studies. These primary studies include numerous soybean growth forms, various stress and experimental treatments, and a range of elevated [CO₂] levels (from 450 to 1250 p.p.m.), with a mean of 689 p.p.m. across all studies. Stimulation of soybean leaf CO₂ assimilation rate with growth at elevated [CO₂] was 39%, despite a 40% decrease in stomatal conductance and a 11% decrease in Rubisco activity. Increased leaf CO₂ uptake combined with an 18% stimulation in leaf area to provide a 59% increase in canopy photosynthetic rate. The increase in total dry weight was lower at 37%, and seed yield still lower at 24%. This shows that even in an agronomic species selected for maximum investment in seed, several plant level feedbacks prevent additional investment in reproduction, such that yield fails to reflect fully the increase in whole plant carbon uptake. Large soil containers (> 9 L) have been considered adequate for assessing plant responses to elevated [CO₂]. However, in open‐top chamber experiments, soybeans grown in large pots showed a significant threefold smaller stimulation in yield than soybeans grown in the ground. This suggests that conclusions about plant yield based on pot studies, even when using very large containers, are a poor reflection of performance in the absence of any physical restriction on root growth. This review supports a number of current paradigms of plant responses to elevated [CO₂]. Namely, stimulation of photosynthesis is greater in plants that fix N and have additional carbohydrate sinks in nodules. This supports the notion that photosynthetic capacity decreases when plants are N‐limited, but not when plants have adequate N and sink strength. The root : shoot ratio did not change with growth at elevated [CO₂], sustaining the charge that biomass allocation is unaffected by growth at elevated [CO₂] when plant size and ontogeny are considered.     

Birth weight of offspring and insulin resistance in late adulthood: cross sectional survey

ObjectiveTo investigate the association between birth weight of offspring and mothers'' insulin resistance in late adulthood.DesignCross sectional survey.SettingGeneral practitioner''s surgeries in 23 towns in Great Britain.Participants4286 women aged 60-79 years.ResultsBirth weight of offspring was inversely related to maternal insulin resistance in late adulthood. For each 1 kg higher birth weight of offspring, women had a 15% reduction in the odds of being in the fourth with highest insulin resistance, compared to other fourths (odds ratio 0.85; 95% confidence interval 0.71 to 1.00). This increased to 27% (0.73; 0.60 to 0.90) after adjusting data for potential confounders. A U shaped relation between birth weight of offspring and diabetes in older age was found; women with the lightest and heaviest offspring had the highest prevalence of diabetes.ConclusionsBirth weight of offspring is inversely related to the mother''s insulin resistance in late adulthood, despite the association of glucose intolerance during pregnancy with heavier offspring at birth. Common genetic factors contribute to the relation between birth weight and risk of cardiovascular disease and diabetes in adults.

What is already known on this topic

Small birth weight is related to increased risk of cardiovascular disease and diabetes in adulthood; the underlying mechanisms are unclearSmall birth weight of offspring is related to parental cardiovascular disease, suggesting that common genetic factors affect birth weight and the risk of disease in adulthoodGenetic factors associated with the metabolism of insulin are plausible in linking birth weight and cardiovascular disease (the fetal insulin hypothesis)

What this study adds

Birth weight of offspring is inversely related to maternal insulin resistance in older ageGenetic factors related to both insulin resistance and birth weight explain at least part of the association between birth weight and risk of cardiovascular disease and diabetes in adulthood     

Molecular cloning and nucleotide sequence of a new P450 gene, CYP319A1, from the cattle tick, Boophilus microplus.

We have isolated and sequenced a novel P450 gene (CYP319A1) from the cattle tick, Boophilus microplus. The CYP319A1 cDNA encodes a protein of 531 amino acids with an estimated molecular weight of 60.9k. It contains all highly conserved motifs characteristic of P450 enzymes. Comparison of deduced amino acid sequence with other CYP members shows that the CYP319A1 is more closely related to CYP4 family, but its overall identity to the CYP4 family is less than 40%. Therefore, it was assigned to a new P450 family by the P450 nomenclature committee. A pseudogene which shares high homology with the CYP319A1 was identified. Analysis of genomic sequence of the pseudogene indicated that the pseudogene contains two additional DNA inserts in the coding region, which disrupt the open reading frame. RT-PCR analysis showed that CYP319A1 is expressed in both susceptible and acaricide-resistant ticks.     

Semipreparative isolation of individual cyanobacterial heterocyst-type glycolipids by reverse-phase high-performance liquid chromatography.

Procedures are described for the quantitative, semi-preparative isolation of individual cyanobacterial heterocyst-type glycolipids (HGs) by reverse-phase HPLC (RP-HPLC) and the modifications to conventional techniques necessary to prevent significant HG losses during sample preparation. Total lipids are obtained from cultures of nitrogen-fixing cyanobacteria by triplicate extraction with 200 packed-cell volumes of chloroform/methanol (1/1, v/v), filtered, and redissolved in chloroform for loading onto a short disposable column of acid-washed silica. After removal of neutral lipids, pigments, and the majority of monogalactosyldiacylglycerol with chloroform and chloroform/acetone, HGs are eluted along with other complex lipids in methanol. The complex lipids are then fractionated by TLC and the HGs isolated as two classes of differing mobilities. The individual components of each class are then resolved by isocratic elution with methanol/water (91/9, v/v) from a C18 RP-HPLC column with refractive index detection. Samples of up to approximately 1.0 mg lipid can be completely separated and the major components isolated in high purity from a single run. Structural studies on the major HG of Nostoc azollae show it to be the glycosylated hexacosane-1,3,25-triol found by others in Anabaena cylindrica.     

SOME FACTORS AFFECTING SEXUAL REPRODUCTION OF APHANOMYCES EUTEICHES

Papavizas , G. C, and C. B. Davey . (USDA, ARS, Crops Res. Div., Beltsville, Maryland.) Some factors affecting sexual reproduction of Aphanomyces euteiches. Amer. Jour. Bot. 47(10) : 884–889. Illus. 1960.—Oospores of Aphanomyces euteiches Drechsler were consistently formed in abundance on a medium (SM–2) consisting of mineral salts, D-glucose, thioglycolic acid, Difco “Special Agar-Noble,” and a mixture of amino acids added in proportions found in powdered yeast extract. The isolates of A. euteiches studied differed in their nutritional requirements for sexual reproduction. Isolates 4 and 7 formed oospores abundantly on SM–1 which was smiliar to SM–2 except that DL-glutamic acid was substituted for the amino acid mixture. Isolate 572 did not form oospores on medium SM–1 except when DL-methionine was substituted for thioglycolic acid. Sexual reproduction of isolates 4 and 7 was observed at a wider concentration range of reduced-sulfur-containing compounds than that of isolate 572. Sexual reproduction of the 3 isolates studied was influenced in a dissimilar way by varying concentrations of D-glucose and DL-glutamic acid, or by varying concentrations of D-glucose and of the amino acid mixture. The optimal sugar carbon/amino nitrogen ratio range for sexual reproduction of isolate 572 was about 5–22, whereas that of isolates 4 and 7 was 15–180. The pH range for sexual reproduction was as wide as that for growth. An acid reaction was more favorable than a neutral or alkaline one. The optimal pH range was 4.9–5.4. Vitamins were not essential.