Immunofluorescent localization of a substance immunologically related to insulin in the protocerebral neurosecretory cells of the European corn borer

Summary A substance immunologically related to mammalian insulin was demonstrated by immunofluorescence in one of five types of neurosecretory cells in the protocerebrum of the European corn borer, Ostrinia nubilalis. This A₂ cell type contains a secretory material stainable with paraldehyde fuchsin.E.R.A. CNRS n° 850     

Changes in Agriculture and Abundance of Snow Geese Affect Carrying Capacity of Sandhill Cranes in Nebraska

ABSTRACT The central Platte River valley (CPRV) in Nebraska, USA, is a key spring-staging area for approximately 80% of the midcontinent population of sandhill cranes (Grus canadensis; hereafter cranes). Evidence that staging cranes acquired less lipid reserves during the 1990s compared to the late 1970s and increases in use of the CPRV by snow geese (Chen caerulescens) prompted us to investigate availability of waste corn and quantify spatial and temporal patterns of crane and waterfowl use of the region. We developed a predictive model to assess impacts of changes in availability of corn and snow goose abundance under past, present, and potential future conditions. Over a hypothetical 60-day staging period, predicted energy demand of cranes and waterfowl increased 87% between the late 1970s and 1998–2007, primarily because peak abundances of snow geese increased by 650,000 and cranes by 110,000. Compared to spring 1979, corn available when cranes arrived was 20% less in 1998 and 68% less in 1999; consequently, the area of cornfields required to meet crane needs increased from 14,464 ha in 1979 to 32,751 ha in 1998 and 90,559 ha in 1999. Using a pooled estimate of 88 kg/ha from springs 1998–1999 and 2005–2007, the area of cornfields needed to supply food requirements of cranes and waterfowl increased to 65,587 ha and was greatest in the eastern region of the CPRV, where an estimated 54% of cranes, 47% of Canada geese (Branta canadensis), 45% of greater white-fronted geese (Anser albifrons), and 46% of snow geese occurred during ground surveys. We estimated that a future reduction of 25% in available corn or cornfields would increase daily foraging flight distances of cranes by 27–38%. Crane use and ability of cranes to store lipid reserves in the CPRV could be reduced substantially if flight distance required to locate adequate corn exceeded a physiological maximum distance cranes could fly in search of food. Options to increase carrying capacity for cranes include increasing accessibility of cornfields by restoring degraded river channels to disperse roosting cranes and increasing wetland availability in the Rainwater Basin to attract snow geese using the CPRV.     

A peptide from corn gluten hydrolysate that is inhibitory toward angiotensin I converting enzyme

A peptide (F ₄) that inhibits angiotensin I converting enzyme (ACE) was isolated from corn gluten hydrolysate prepared with Pescalase, a serine protease from Bacillus licheniformis. The N-terminal amino acid sequence of F ₄ was Pro-Ser-Gly-Gln-Tyr-Tyr, having the IC₅₀ value of 0.1 mM. The peptide (F ₄), at 30 mg kg^–1 body weight of rat, antagonized the rat's pressor response to angiotensin I.     

Effects of alpha-lipoic acid on high fructose induced hepatic pathology

Little is known about the pathogenesis of high fructose corn syrup (HFCS) induced hepatic toxicity. We investigated hepatic lesions induced by chronic HFCS consumption and the protective effects of alpha-lipoic acid (ALA) on liver pathology. We used 24 rats allocated randomly into three groups of eight. The HFCS group was given in drinking water for 10 weeks. The ALA + HFCS group was given the same dose of HFCS and ALA also was administered during the last 6 weeks of the experiment. The control group was untreated. The rats were euthanized at the end of 10 weeks and 24 h after the last ALA administration. A significant increase was observed in the serum aspartate aminotransferase (AST) level of the HFCS group compared to controls. Tissue malondialdehyde (MDA) levels also increased significantly and catalase (CAT) activity decreased significantly in the HFCS group. Caspase-3 expression increased significantly in the HFCS group compared to controls. In the ALA treated group, the levels of MDA, CAT and caspase-3 returned to near control levels. HFCS caused hepatic toxicity by increasing oxidative stress and apoptosis. ALA administration ameliorated the pathological changes.     

Adenine nucleotide translocation in plant mitochondria

The rapid translocation of external ADP-[^14C]by corn mitochondria is inhibited by high concentrations of atractyloside with enhanced inhibition occurring in the presence of Mg²⁺. This translocation is also inhibited by AMP or ATP but CDP, GDP, IDP or UDP have little effect. Backward exchange of internal ADP-[¹⁴C] occurs in the presence of AMP, ADP or ATP but is not promoted by other nucleoside diphosphates. It is suggested that the adenine nucleotide (AdN) carrier is specific for ADP and ATP and that apparent translocation of AMP is a result of adenylate kinase activity. The translocated ADP can be separated into 3 components: (1) atractyloside-insensitive binding; (2) carrier-bound ADP saturated at ca 30 μM external ADP; and (3) exchanged ADP saturated as ca 5 μM external ADP. It is suggested that the adenine nucleotide carrier of plant mitochondria possesses similar properties to the classical carrier of vertebrate mitochondria.     

The sensitivity of shoot growth of corn to the least limiting water range of soils

The least limiting water range (LLWR), the range in soil water content within which limitations to plant growth associated with water potential, aeration and mechanical resistance to root penetration are minimal, has been proposed as an index of the structural quality of soils for crop growth. An hypothesis that is implicit in the proposed use of LLWR as an index of soil structural quality is that crop growth is negatively related to the proportion of the total number of measurements in which the water content falls outside the LLWR (p_out) and therefore given a certain climate positively related to the magnitude of the LLWR. The objective of this investigation was to test the hypothesis that plant response, specifically shoot growth rate of corn (Zea mays L.), can be functionally related to p_out and the LLWR of soils. The study was carried out on a farm with a side-by-side comparison of no-till and conventional-till. Thirty two paired sampling sites were located along the two transects. The LLWR and p_out were calculated for the 0–20 cm depth in each sampling site. Shoot growth rate (SGR) was measured during a 17 and 16 day period in 1992 and 1993, respectively that corresponded to the 10–11 leaf stage. Although the variation in p_out accounted for a larger percentage of the variation in SGR than did LLWR, the correlation between SGR and LLWR was high and justifies further studies to determine if crop yield can be related to LLWR under different soil and climatic conditions.     

Characterization of the Vacuolar Proton Pumps of the Cortex,Stele and Tip of Maize Roots: Effects of Salinity

Tonoplast and Golgi ATP-driven proton pumping was measured in membrane vesicles isolated from the cortex, stele and tip of maize roots. Two nitrate-sensitive peaks of tonoplast proton pumping were detected on sucrose gradients, a light peak at 16% sucrose, believed to represent small vacuoles, and a denser peak at 25% sucrose, possibly derived from large vacuoles. The nitrate-insensitive Golgi peak occurred at 31 % sucrose. Membrane preparations of the stele and tip were active in H⁺-transport activity and were rich in mitochondria. In contrast, the membranes of the cortex had low levels of both ATP-driven proton pumping and mitochondrial activities. Salinity caused a doubling of the tonoplast H⁺-transport activity of the tip and cortex, particularly in the 25 % sucrose peak. The enhancement of the 25 % peak by salinity was correlated with an increase in vacuolation of the tip. The stelar proton pumps were only slightly stimulated by salinity. The results indicate that the cortex of maize roots is deficient in the metabolic machinery needed for vacuolar solute accumulation, but that it shows some ability to adapt to saline conditions. The physiological implications of these findings are discussed.