The influence of storage on the physiology and productivity of Kennebec seed potatoes

Kennebec seed potatoes were stored in various atmospheres of O₂ and CO₂ at 32 and 41 F (0 and 5 C). Samples were removed every 6 weeks for measurement of bud and parenchyma tissue respiration, rate of ion loss from tissue sections and reducing sugar content. Potatoes remaining at the end of the storage period were warmed, cut and planted immediately in a randomized complete block design for yield evaluation. Intact tuber respiratory rates were higher at 32 F than 41 F. Increasing CO₂ increased respiratory rates and decreasing O₂ decreased respiratory rates at both temperatures. Decreasing O₂ concentration significantly decreased reducing sugar at both 32 and 41 F. Increasing CO₂ significantly increased reducing sugar at 41 F but not at 32 F. Kennebec potatoes did not tolerate added CO₂ at 32 F but did survive 4% CO₂ at 41 F. Reducing oxygen decreased the tolerance to CO₂. The onset of carbon dioxide injury was not clearly evident from changes in bud and parenchyma tissue respiration or in loss of electrolytes from cut tissue sections. However, CO₂ accelerated tuber breakdown by unidentifiedFusarium Spp. No significant differences in yield were observed between treatments that survived the storage period.     

Shedding of Coxiella burnetii in ewes in two pregnancies following an episode of Coxiella abortion in a sheep flock.

Coxiella burnetii infection in pregnant sheep typically causes abortion or the birth of weak lambs. Two C. burnetii-related abortions in a group of 34 pregnant ewes were reported at their first lambing in our research institute. The seroprevalence of C. burnetii infection and bacteria shedding were investigated using an ELISA and PCR, respectively, during the course of two subsequent pregnancies. None of the ewes examined seroconverted from negative to positive at the time of the second and the third parturition and most of the ewes that were seropositive at the abortion episode remained positive throughout the investigation. The two successive pregnancies resulted in the birth of healthy lambs without PCR evidence of Coxiella infection from placenta and vaginal swabs taken postpartum. PCR assay performed on vaginal swabs taken from all animals 1, 5 or 12 days after the second lambing were also negative for Coxiella. However, one ewe that had previously experienced C. burnetii shedding at the first lambing excreted the bacteria in the genital tract after the third parturition. The bacteria could not be detected by PCR in milk and faecal samples taken up to 12 days after both parturitions.     

Relationship of glycaemic index with cardiovascular risk factors: analysis of the National Diet and Nutrition Survey for people aged 65 and older

OBJECTIVE: To identify associations between dietary glycaemic index (GI) and weight, body mass index and other risk factors for cardiovascular disease (CVD) - waist-to-hip ratio (WHR), lipoprotein fractions, triacylglycerols (TAG) and blood pressure (BP) - in an older British population. DESIGN: Cross-sectional dietary, anthropometric and biochemical data from the National Diet and Nutritional Survey for adults aged over 65 years were reanalysed using a hierarchical regression model. Associations between body weight, CVD risk factors, and dietary factors including GI and fibre intakes were explored among 1152 healthy older people living in the UK between 1994 and 1995. RESULTS: In the unadjusted model, GI was significantly and directly associated with TAG (beta = 0.008 +/- 0.003) and diastolic BP (beta = 0.325 +/- 0.164) in males. These relationships were attenuated and non-significant after adjustment for potential confounding factors. WHR (beta = 0.003 +/- 0.001) and TAG (beta = 0.005 +/- 0.002) were significantly predicted by GI in males and females combined. The association with WHR was attenuated by adjustment for sex, age, region and social class; the relationship with TAG was non-significant after adjustment for other potential dietary confounders. CONCLUSION: After controlling for potential confounders, no clear links were detected between GI and body weight or other CVD risk factors. This study provides little evidence for advising the consumption of a low-GI diet in the elderly to prevent weight gain or improve other CVD risk factors.     

Reproductive dynamics and nursery habitat preferences of two commercially important Indo-Pacific red snappers <Emphasis Type="Italic">Lutjanus erythropterus</Emphasis> and <Emphasis Type="Italic">L. malabaricus</Emphasis>

Red snappers were examined for reproductive biology and age-0 habitat preferences. Spawning in red snappers occurred throughout the year in northern Australia and eastern Indonesia; at least 10–30% of females and 40–80% of males were in ripe or spawning condition in most months. Northern Australian populations showed a spawning peak from July to December (L. erythropterus) and September to March (L. malabaricus). Eastern Indonesian L. malabaricus had a less defined pattern with two peaks: January–March and October. Size at first maturity was 240 mm for males and 250–300 mm for females. L ₅₀ estimates were similar between species in northern Australia: 270–280 mm (males) and 350–370 mm (females). Maximum batch fecundity was 676,100 oocytes for L. erythropterus and 997,000 oocytes for L. malabaricus. Higher mean abundances of age-0 L. erythropterus were found in silty and coarse sand/rubble estuarine habitats of northern Australia (456 ± 119 fish/km²) compared with sandy coastal habitats (5 ± 3 fish/km²). Most age-0 snapper caught at Sape (eastern Indonesia) were L. malabaricus (91%) with mean abundances of 312 ± 14 fish/km². The similarities in the reproductive characteristics of red snappers suggest that successful management approaches adopted in northern Australia should be considered in eastern Indonesia.