Field performance of transgenic Russet Burbank and Lemhi Russet potatoes

Transformed Russet Burbank and Lemhi Russet clones which contained three different transgene constructs were evaluated for performance under field conditions in Idaho. The transgenic lines were characterized over two growing seasons, using plants grown from both greenhouse produced minitubers (first year) and field grown seed (second year). Individual clones were evaluated for a variety of agronomic and quality properties. Many of the transformed clones showed reduced yield and increases in percent malformed and undersized tubers. Other characteristics, such as specific gravity and fry color, showed less variability. The variation observed in non-transgenic clones regenerated from tissue culture was less than that of the transformed lines. Out of an original population of 57 transgenic lines in tissue culture, maintenance of key agronomic and quality properties of the parental material was observed in only four clones. These results suggest that experiments designed to generate transgenic lines for the marketplace should be initiated with a large number of transgenic clones.     

Uterine Infection Influences Size and Follicular Fluid Composition of the Largest Follicle in Buffalo (Bubalus bubalis)

The effect of uterine infection on size and follicular fluid composition of the largest follicle was studied in buffalo. Reproductive tracts were collected from 102 graded Murrah buffaloes at an abattoir. Uterine infection was diagnosed by physical examination of uterine mucus, white side test and uterine cytology. Samples with pus‐containing mucus, positive reaction on white side test and/or >5% neutrophils were considered to be positive for uterine infection. Diameter of the largest follicle was measured, and follicular fluid was aspirated and assayed for nitric oxide (NO), ascorbic acid (AA), cholesterol, oestradiol (E₂) and progesterone (P₄). Infected buffaloes had smaller‐sized (p < 0.0001) largest follicles than non‐infected buffaloes. Follicular fluid collected from the largest follicle in infected buffaloes had greater (p < 0.0001) NO and P₄ concentrations coincident with lesser AA (p < 0.001), cholesterol (p < 0.0001) and E₂ (p < 0.0001) concentrations. Results indicated that uterine infection has an inhibitory effect on growth of the largest follicle in buffalo. The changes in follicular fluid composition in infected buffaloes suggest that the direct effect of uterine infection on ovarian function may be mediated through an alteration in the follicular microenvironment. Greater NO and lesser AA concentrations in the follicular fluid of infected animals are novel findings.     

Proinflammatory Cytokine and Chemokine Gene Expression Profiles in Subcutaneous and Visceral Adipose Tissue Depots of Insulin‐Resistant and Insulin‐Sensitive Light Breed Horses

Background: Insulin resistance has been associated with risk of laminitis in horses. Genes coding for proinflammatory cytokines and chemokines are expressed more in visceral adipose tissue than in subcutaneous adipose tissue of insulin‐resistant (IR) humans and rodents. Hypothesis/Objectives: To investigate adipose depot‐specific cytokine and chemokine gene expression in horses and its relationship to insulin sensitivity (SI). Animals: Eleven light breed mares. Methods: Animals were classified as IR (SI = 0.58 ± 0.31 × 10^?4 L/min/mU; n = 5) or insulin sensitive (IS; SI = 2.59 ± 1.21 × 10^?4 L/min/mU; n = 6) based on results of a frequently sampled intravenous glucose tolerance test. Omental, retroperitoneal, and mesocolonic fat was collected by ventral midline celiotomy; incisional nuchal ligament and tail head adipose tissue biopsy specimens were collected concurrently. The expression of tumor necrosis factor‐α (TNF‐α), interleukin (IL)‐1β, IL‐6, plasminogen activator inhibitor‐1 (PAI‐1), and monocyte chemoattractant protein‐1 (MCP‐1) in each depot was measured by real‐time quantitative polymerase chain reaction. Data were analyzed by 2‐way analysis of variance for repeated measures (P < .05). Results: No differences in TNF‐α, IL‐1β, IL‐6, PAI‐1, or MCP‐1 mRNA concentrations were noted between IR and IS groups for each depot. Concentrations of mRNA coding for IL‐1β (P= .0005) and IL‐6 (P= .004) were significantly higher in nuchal ligament adipose tissue than in other depots. Conclusions and Clinical Importance: These data suggest that the nuchal ligament depot has unique biological behavior in the horse and is more likely to adopt an inflammatory phenotype than other depots examined. Visceral fat may not contribute to the pathogenesis of obesity‐related disorders in the horse as in other species.     

Modification of Potato Steroidal Glycoalkaloids with Silencing RNA Constructs

Steroidal glycoalkaloids (SGAs), while found in many solanaceous plants, can accumulate to unacceptably high levels in potato tubers. The two primary SGAs that occur in potatoes are the tri-glycosylated alkaloids, α-solanine and α-chaconine. The first glycosylation steps in their biosynthetic pathways are performed by the regulated enzymes SGT1, the UDP-galactose:solanidine galactosyltransferase, and SGT2, the UDP-glucose:solanidine glucosyltransferase, respectively. Using fragments of the Sgt1 and Sgt2 genes to produce small inhibitory RNAs (siRNA), we have been able to down-regulate each branch of the pathway. The use of the siRNA approach increases the efficiency of producing transgenic plant lines with reductions in individual SGAs but further research is required to achieve reductions in levels of total SGA accumulation.