bluuebunny/crossref_metadata_2025 huggingface dataset:
Increased growth and uptake of nutrients by corn plants treated with low levels of simazine
Authors: Freney JR
Published: November 2004

Simazine applications of 1.5 p.p.m. to soil in pots in a glasshouse increased dry matter yields and uptake of nitrogen in corn only when additional nitrogen was applied to the soil. The proportions of protein and non-protein nitrogen in the topgrowth were not affected. Application of simazine at this rate without addition of nitrogen resulted in increased leaf area but did not significantly affect yield. Simazine provided a stimulus to the plant early in its life and enabled it to grow faster than the control plant. When the supply of available nitrogen was exhausted the simazine effect decreased. When incubated with soil, simazine did not increase mineralization of soil organic nitrogen, nor did it have any effect on immobilization of mineral nitrogen. Simazine applied at 0.06 p.p.m. in solution culture increased the yield of corn tops by 36%, the uptake of nitrogen by 37%, phosphorus by 25%, magnesium by 24%, and potassium by 41 %. It had no effect on the yields of roots. The results suggest that simazine increased plant growth by a direct effect on plant metabolism and not through any interaction with the soil.
The effects of soil moisture stress on the growth of barley. II. Grain growth
Authors: Aspinall D
Published: November 2004

The influence of water stress on grain growth has been investigated under conditions of intermittent stress with pot-grown plants and under longer periods of stress with plants grown in lysimeters. Premature cessation of growth was induced by even a moderate water stress, but the rate of grain growth (in dry weight) in the early stages of development was reduced only by severe water stress. There was evidence for an actual loss of dry matter in the final stages of maturation where plants were subjected to severe water stress. Grain moisture content was relatively unaffected by water stress during the major period of grain development, although grain water content dropped with increasing water stress during ripening. Spikelet chlorophyll content was also reduced by water stress, particularly in the later stages of grain development. Indirect evidence indicated that translocation of assimilate from the leaves to the ear was reduced by a moderate water stress. Tne significance of these findings in elucidating the mechanism of action of water stress on grain growth is discussed.
Body composition in vivo. VII. Relation between red cell volume and total body water in ewes
Authors: Panaretto BA , Little DA
Published: November 2004

The relationship between total body water and red cell volume was determined in a group of non-pregnant crossbred ewes, in an endeavour to obtain a method which did not necessitate the use of radioisotopes for determining body composition. Total body water could be predicted from red cell volume. The 95% confidence interval for a mean value for total body water, predicted from the red cell volume, was ±18.8% of the mean. All other relations which can be derived between the red cell volume and other body parameters depended on this relation. The calculation of body composition from measurements of the red cell volume is discussed.
Efficiency of conversion of food to wool at two nutritional levels by three merino strains
Authors: Dunlop AA , Dolling CHS , Carpenter MT
Published: November 2004

Efficiency of conversion of fodder to wool in a fine-wool (F), a medium-wool (B), and a strong-wool (S) strain of Merino was estimated by measuring individual fodder consumption and wool production of nine wethers of each strain in two periods, each of 16 weeks. In the first period lucerne chaff and wheat were fed in a 7.2/1 ratio (dry basis) at a maintenance level. In the second, lucerne chaff and wheat were fed in a 2.8/1 ratio at approximately 1.4 times maintenance level. The efficiencies of the strains in the two periods in terms of pounds of oven-dry wool produced per 100 therms of net energy consumed were:
Strain Maintenance Maintenance x 1.4
F 1.76 1.52

B 2.03 1.82

S 2.19 1.90
The overall strain differences F v. B and F v. S were significant (P < 0.001) but the remaining difference was not significant. Interactions of strains and nutritional levels were not significant. Individual sheep within strains tended to remain in a similar order of efficiency from one nutritional level to the other, the within-strain correlation between levels being estimated as 0.89. The results suggest that selection of strains and to a lesser extent of individuals on the basis of efficiency will not be seriously affected by the energy level at which efficiency is measured. In a digestion experiment involving all 27 animals of the efficiency experiments, each fed at its maintenance ration, differences between strains in digestibility of organic matter and of protein were extremely small and were non-significant. It is concluded that strain differences in efficiency depend largely on differences in utilization.
The effects of the plane of nutrition in early post-natal life on the subsequent growth and development of cattle
Authors: Wardrop ID
Published: November 2004

The effect of the plane of nutrition in the first 13 weeks of post-natal life of cattle on their subsequent growth rate, body shape, and carcass composition up to 12 months of age was studied. No compensatory growth to 12 months of age was observed in calves reared to 13 weeks on low planes of nutrition. There were no significant differences between Friesian and Hereford x Friesian calves, or between males and females in empty body weight or weight gains. Treatment up to 13 weeks of age had no effect on heart girth, round, head length and width, and cannon bone length, but the remaining body measurements were reduced by low planes of nutrition during this period. Differences in carcass composition were largely a reflection of the differences in empty body weight. The carcasses of the males were heavier than those of the females and the females contained a higher proportion of fat. Carcass composition, as estimated by shin dissection, indicated that Friesian calves contained more muscle than the Hereford x Friesians, and the males more muscle than the females.
The metabolic rate of fasting sheep in relation to total and lean body weight, and the estimation of maintenance requirements
Authors: McCGraham N
Published: November 2004

Calculation of maintenance energy requirements from fasting energy loss is discussed. The fasting energy expenditure and urinary nitrogen loss of six Merino wethers (5–7 years old) were determined at body weights of 60, 50, 40, and 30 kg by means of closed-circuit indirect calorimetry. Body composition was estimated from tritiated water space. Similar measurements were made on 51 other adult sheep of various types and on 12 young animals. Simple correlations between metabolic rate and total or lean body weight of adult sheep are described. There was no evidence of specific effects on these correlations due to age of adults, sex, breed, or body condition. The metabolic rate per unit of lean body weight was the same (c. 27 kcall24 hr/lean kg) for sheep as for man; it was up to twice as great for young animals as for adults. On the average, 24% of the fasting heat production of the sheep was derived from protein oxidation; the proportion tended to increase as the sheep lost condition. Differences between sheep in rate of weight loss during undernutrition could not be accounted for in terms of the measured metabolic rates.
Epidemiology of Cauliflower Mosaic virus in South Australia
Authors: Randles JW , Crowley NC
Published: November 2004

Results are presented of 3 years of aphid trapping and 3 years of surveys of the incidence of infection with cauliflower mosaic virus in Brassica crops at two sites in South Australia. Mosaic infection has been found to be of importance only in cauliflower plantings. The incidence of the disease varied greatly at the two sites, which were located in climatically different regions. In the Adelaide Hills significant spread of the disease occurred only through the autumn months March, April, and May, and in only one of the three years did the incidence of the disease reach epidemic proportions. On the Adelaide Plains spread of the disease occurred throughout the cooler months of the year, from March till September. At both locations increasing incidence of the disease followed increases in the number of trapped aphid vector species. Results indicate that the most important vector in the field is likely to be Brevicoryne brassicae. Trials suggest that seed-bed infection with the virus can be reduced by the use of barrier crops.
Oestrogenic activity and metabolism of certain isoflavones in sheep
Authors: Braden AWH , Hart NK , Lamberton JA
Published: November 2004

Pure genistein, biochanin A, and formononetin when administered to ovariectomized ewes by intraruminal (i/r) infusion appear to have oestrogenic activities of the same order. Coumestrol given similarly has activity about 15 times as great. Genistein, biochanin A, and coumestrol appear to be considerably less active when given i/r than when injected intramuscularly (i/m), but formononetin is more active i/r than i/m. This may be related to the lower solubility of formononetin. Examination of the urinary phenols before and after treatment showed that almost all the administered isofiavone underwent metabolic degradation. Genistein and biochanin A appeared to be largely excreted as p-ethylphenol, but only about 5% of the formononetin was accounted for as detectable metabolites, of which a major one was equol.
Phosphorus turnover in sheep
Authors: Tomas FM , Moir RJ , Somers M
Published: November 2004

Rumen fluid, serum, and parotid salivary inorganic phosphorus concentrations in sheep given four levels of dietary phosphorus (0.42–4.02 g/day) were directly related to phosphorus intake. There was a very high correlation (r = +0.91; P < 0.001) between inorganic phosphorus concentrations in centrifuged rumen fluid and in parotid saliva. Serum inorganic phosphorus concentrations were positively correlated with those of saliva (r = +0.64; P< 0.05) and also with those in centrifuged rumen fluid (r = +0.75; P<0.01). The range in the mean daily saliva volumes collected from one parotid gland in each sheep was 3.2 to 4.2 l/day. The calculated minimum total salivary phosphorus secretion ranged from 3.0 g/day on the lowest dietary phosphorus intake to 5.3 g/day on the highest, the corresponding ratios of salivary to dietary phosphorus being from 7.24 to 1 .32 g/g. It appeared that salivary phosphorus was the major source of phosphorus to the rumen, and was also the principal determinant of rumen fluid inorganic phosphorus levels.
Wool fibre shedding in some Merino sheep
Authors: Ryder ML
Published: November 2004

Four sheep were investigated by monthly skin sampling for 3 years in Australia, and four sheep by quarterly sampling for 3 years in Scotland. Those in Australia had shedding in 30–50% of the samples while those in Scotland had shedding in only 15–30%, but in both the incidence of brush ends was less than 1%.
Isotopic studies on the uptake of nitrogen by pasture plants. III. The uptake of small additions of 15N-labelled fertilizer by Rhodes grass and Townsville lucerne
Authors: Vallis I , Haydock KP , Ross PJ , Henzell EF
Published: November 2004

Small additions of (15NH4)2SO4 and K15NO3 were used to investigate the nitrogen economy of Townsville lucerne (Stylosanthes humilis H.B.K.) and Rhodes grass (Chloris gayana Kunth.) grown separately and together in pots. Rhodes grass reduced the total yield of nitrogen per plant in associated Townsville lucerne to about half that of Townsville lucerne in pure stand. It appears that the Rhodes grass seedlings competed strongly with Townsville lucerne for available soil nitrogen during the first 5 weeks of the experiment. When the two species were grown together, Rhodes grass took up about 20 times as much 15N as the Townsville lucerne during the first 9 weeks, and about 8 times as much between 9 and 13 weeks after sowing. This ratio was the same for (15NH4)2SO4 as for K15NO3. When the two species were grown separately they took up equal amounts of 15N between 9 and 13 weeks after sowing. Estimates of soil nitrogen uptake at 5 weeks showed that 47% of the nitrogen in the Townsville lucerne growing with Rhodes grass had come from the soil. At 9 weeks the cumulative uptake of soil nitrogen by this Townsville lucerne was only 6%, and at 13 weeks only 3%, of its total nitrogen yield. No significant transfer of unlabelled nitrogen from legume to grass was detected. Attention is drawn to the assumption used in calculating uptake of soil nitrogen by the legume. It is suggested that this tracer technique can be applied to 15N experiments in the field.
Mineral elements in temperate crop and pasture plants. II. Calcium
Authors: Loneragan JF , Gladstones JS , Simmons WJ
Published: November 2004

Twenty-five annual crop and pasture plant varieties from 21 species were grown on a lateritic gravelly sand at Gidgegannup in Western Australia. Plant tops were sampled at three stages during the growing season and at maturity. This paper presents data for calcium contents of the tops. Calcium concentrations varied widely among species, and to a smaller extent with age and among plant parts at maturity. Species rankings varied only slightly among harvests. Herbs and all legumes except lupins maintained high calcium concentrations throughout the growing season. By contrast, the concentrations in grasses, and even more markedly in the cereals, were low in the young plants and declined further as the season progressed. Concentrations in lupins were intermediate in the first two harvests, but fell precipitously towards maturity to levels similar to those in grasses. Despite low overall levels in the mature plant, seeds of lupins were generally higher in calcium concentration than other legume seeds and several times as high as cereal grains. Calcium concentrations of plant tops correlated reasonably well with published data on cation exchange capacities (CEC) of roots when taken over the whole range of species, but within major plant groups the correlation was poor. It is suggested that, rather than signifying a causal relationship between root CEC and calcium concentration in the tops, the results may merely indicate that dicotyledonous plants tend to have high calcium concentrations and CEC values while monocotyledonous plants have low. It is also suggested that if any such causal relationship does exist, its origins are more likely to lie in the CEC properties of the tops than in those of the roots.
The nature of the perennial response in Mediterranean grasses. I. Water relations and summer survival in Phalaris
Authors: McWilliam JR , Kramer PJ
Published: November 2004

An important factor in the survival of Phalaris tuberosa, a typical Mediterranean perennial grass, is the ability of its deep root system to supply water during the summer to the dormant culms at the soil surface. This behaviour contrasts with that of the related annual P. minor, which is unable to exploit subsoil moisture, and dies as soon as the surface moisture is exhausted. The volume of water supplied by the perennial roots is sufficient to offset transpiration losses and maintain a favourable water balance in the dormant culms during the summer stress. The importance of this water source for survival is indicated by the death of plants whenever this supply is interrupted by severing deep roots. In field soils under drought conditions roots of the perennial have been followed to a depth of 7 ft in subsoil containing available moisture. The large metaxylem vessels and heavily suberized endodermis which are a feature of these roots suggest that they are well adapted to transport water up through the dry surface soil to the base of the dormant culms. The culms also show typical xerophytic characteristics which help to minimize water loss during the summer, and maintain favourable conditions for the survival of the dormant buds which develop at the basal nodes. These conclusions concerning the survival of the perennial have been drawn from plants growing under natural conditions, and also from more detailed studies under controlled environments. They appear to be of general significance for the perennial grasses adapted to the drier Mediterranean environments and form the basis of the perennial response found in this group.
The influence of age structure on total productivity in breeding flocks of Merino sheep. I. Flocks with a fixed number of breeding ewes, producing their own replacements
Authors: Turner HN , Brown GH , Ford GH
Published: November 2004

In a flock of breeding ewes of fixed size, the number of age groups of rams and ewes influences the annual rate of genetic gain in any character under selection. The number of ewe age groups also influences the number of surplus stock aged 1½ years, and the number cast for age, as well as the amount and quality of wool obtained. The latter is also influenced by the proportion of ewes which rear no lambs, one, or two, as well as the proportion themselves born in multiple births or as the progeny of young ewes. In this paper, all these influences are considered in determining the age structure of the breeding flock which gives the greatest number of surplus stock and the greatest relative wool return. To combine the two, relative weights have to be given to wool and surplus stock. One such set of weights has been used, and the conclusion has been drawn that two age groups of rams, with either five or six age groups of ewes, give optimal return, the number of ewe groups depending on the level of reproduction rate. This conclusion depends on the relative weights used. In cases where numbers of animals are of supreme importance, such as after a drought or at a time of increasing pasture improvement, then retaining ewes to an older age would increase the number of surplus young stock.
Nodulation failure in Trifolium subterraneum L. CV. Woogenellup (Sum. Marrar)
Authors: Gibson AH
Published: November 2004

The symbiotic relationship between Trifolium subterraneum L. cv. Woogenellup and a number of strains of Rhizobium trifolii was examined in tube and pot culture experiments. Plants grown in agar culture with the roots darkened and at 22°C either failed to nodulate or formed nodules slowly when inoculated with a number of strains; with other strains nodulation was prompt and the effectiveness levels were similar to those achieved with other subterranean clover cultivars. Exposure of the roots to light in tube culture experiments promoted nodulation by the "slowly nodulating" strains; higher root temperatures (28°) also promoted nodulation. Nine samples of the cultivar from widely separated sources behaved in a similar manner. Approximately 50% of 287 field isolates of R. trifolii from three localities were slow to nodulate this host, even when the roots were exposed to light. The proportion of field isolates nodulating the host promptly, and the effectiveness of nodulation achieved varied within and between the localities from which the isolations were made. R. trifolii strain TA1 failed to nodulate Woogenellup adequately in a pot culture experiment with two soils differing in the size of their natural population of R. trifolii (< 2/g, 104/g). Under the same conditions, three other strains formed a high proportion (> 80%) of the nodules in both soils, as determined by serological analysis of isolates from the nodules. A competition study with mixed inoculants showed that strain CC2480a formed a higher proportion of the nodules on cv. Woogenellup than strains WA67 or WU290, the present commercial inoculant strains. The results are discussed in relation to conflicting reports of poor nodulation of Woogenellup in the field, and of satisfactory nodulation in the laboratory and the glasshouse.
Efficiency of conversion of food to wool. III. Wool production of ewes selected for high clean wool weight and of random control ewes on restricted and unrestricted food intakes in pens
Authors: Dolling CHS , Piper LR
Published: November 2004

The clean wool production (W), gross energy intake (I), and body weight (B) of individually fed medium Peppin ewes representative of two groups, one (selected, S) genetically superior in W to the other (control, C), have been measured under restricted and ad libitum feeding of lucerne chaff in pens. Differences in favour of the S group were observed for W and W/I under both regimes, the respective relative values of S/C being under restricted feeding 110/100 and 112/100, and under ad libitum feeding 113/100 and 112/100. Of these between-group differences, only W/I on restricted feeding was significant (P < 0.05). Differences between groups for B and I were small and not significant. On restricted feeding the S/C values were 98/100 for both; on ad libitum feeding they were 99/100 for B and 101/100 for I. When the data from the two feeding regimes were combined, the between-group differences in both W and W/I were significant (P < 0.05), but no significant group x nutritional level interaction was observed in any character. The two levels of nutrition in the pens yielded wool production rates similar to those observed contemporaneously on natural pastures. There were large positive phenotypic correlations between net efficiency (W/I under restricted feeding) and gross efficiency (W/I under ad libitum feeding), and between net efficiency and W under both regimes. There were also positive phenotypic correlations between I and both W (moderate) and B (large) under ad libitum feeding. W/I accounted for 92% of the between-group (genetic) and 70% of the within-group (phenotypic) variation in W. There was no significant difference in plasma protein-bound iodine (PBI) between S and C ewes, while correlations between W and PBI were not significant within either group. The energetic efficiency of the wool production process is discussed; in this experiment no more than 1.5% of the energy consumed appeared as energy in the form of wool fibre.
A virus complex of subterranean clover
Authors: Grylls NE , Peak JW
Published: November 2004

A study was made of subterranean clover plants from areas of New South Wales where clovers were not re-establishing. Eight field isolates of diseased plants were collected in central and southern New South Wales and in the Australian Capital Territory. Mixed infections of strains of subterranean clover stunt virus (SCSV) and a bean yellow mosaic virus (BYMV) were transmitted from the isolates. Four species of aphids, Aphis cvaccivora (Koch), A. gossypii (Glov.), Macrosighum euphorbiae (Thomas), and Myzus persicae (Sulz.), transmitted strains of SCSV and the BYMV and a mixture of these to a number of legumes. Four stable strains of SCSV were separated after a large number of transfers and selections. BYMV was isolated by mechanical inoculation. One Australian cultivar, four Mediterranean introductions, and one intersubspecific hybrid of subterranean clovers were highly resistant to two strains of SCSV and to BYMV. Mixed infection with SCSV and BYMV and infection with one severe strain of SCSV seriously reduced pod formation and seeding in peas and canning beans as well as in subterranean clover.
Comparison of the effects of several stressing agents on the adrenal glands of normal and hypophysectomized sheep
Authors: Panaretto BA , Ferguson KA
Published: November 2004

.Experiments are presented to show that a number of stressing agents produced their deleterious effects on the adrenals of the host by causing excessive adrenocorticotrophin (ACTH) production. Adrenocortical haemorrhages, that were evident when metopirone, adrenaline, or endotoxin was infused into normal sheep, were not seen following similar infusions into ACTH-maintained hypophysectomized sheep. Infusion of 50 i.u. ACTH over 11 hr, however, caused adrenocortical haemorrhages in both normal and hypophysectomized sheep. These results support the suggestion that excessive ACTH production causes the changes seen in the adrenals of sheep that succumb to cold exposure.
The effect of phosphorus on the growth and chemical composition of some tropical pasture legumes. II. Nitrogen, calcium, magnesium, potassium, and sodium contents
Authors: Andrew CS , Robins MF
Published: November 2004

This paper describes the effect of phosphorus on nitrogen concentration and on the total and individual concentrations of the cations calcium, magnesium, potassium, and sodium in the plant tops of 10 tropical legumes and one temperate legume when grown on two soils of different type, a light-textured solodic soil and a gley soil. Species used were Phaseolus lathyroides, P. atropurpureus, Stylosanthes humilis, Centrosema pubescens, Glycine javanica, Lotononis bainesii, Medicago sativa, Desmodium uncinatum, D. intortum, Vigna luteola, and Leucaena leucocephala. The nitrogen concentrations in the plant tops were increased by phosphorus supply, and good correlations were established between the nitrogen and phosphorus concentrations in the plant tops. When sodium dihydrogen phosphate was used as the source of phosphate, the sodium concentration in V. luteola, M. sativa, and L. bainesii was increased. Other species were not affected. Increasing phosphate supply as monocalcium phosphate had little effect on plant calcium concentration, but brought about an increase of magnesium in P. lathyroides and P. atropurpureus. In the solodic soil particularly, increases in phosphate supply in most species caused reductions in the potassium concentration, partly compensated by increases in the magnesium and calcium concentrations. Concentrations of the cations in the plants reflected the soil exchangeable cation composition. Plant species differed in their cation status. P. atropurpureus and P. lathyroides were relatively high in magnesium, L. bainesii and D. intortum in potassium, V. luteola, L. bainesii, M. sativa, and P. lathyroides in sodium, and C. pubescens and S. humilis in calcium.
The digestion of pasture plants by sheep. IV*. The digestion of Phalaris tuberosa at different stages of maturity
Authors: Hogan JP , Weston RH , Lindsay JR
Published: November 2004

A study was made of the composition, intake, and digestion of dried Phalaris tuberosa forage that had been harvested at three stages of maturity. Advancing maturity was associated with: (i) decreased food intake; (ii) increased expenditure of time and energy in chewing activities; (iii) decline in the rate of flow of digesta from the abomasum though not from the rumen; (iv) decline in digestibility in the whole tract of organic matter, nitrogen, and the structural carbohydrates; (v) decline in the digestion of fibre in the rumen relative to that occurring in the whole tract; (vi) decline in the quantities of volatile fatty acids and amino acids made available to the animal. By contrast only small differences attributable to maturity were observed in: (i) the distribution of digestion of organic matter between stomach and intestines; (ii) the digestibility of nitrogen other than ammonia in the intestines; (iii) the proportions of digestible organic matter derived from volatile fatty acids and amino acids; (iv) the proportions of individual amino acids in the digesta passing to the intestine. It was calculated that microbial piotcin contributed 33, 38, and 47% of the protein passing from the stomach to the intestincs with the diets of advancing maturity. Most of the remaining protein was presumably of dietary origin. About 80% of the crude protein in the digesta was present in the form of amino acids, and the quantities of amino acids released in the intestines were calculated to be equivalent to 64–66 g/100 g crude protein intake. With advancing maturity of the diets the plasma levels of the essential ammo acids except lysine, histidine, and arginine declined; there was little effect of diet on the plasma levels 01 non-essential amino acids. However, relative to total essential amino acids, the ratios of valine and leucine decreased with advancing maturity of the diet while those of lysine, histidine, glutamate, glycine, alanine, and serine increased.

* Part 111, Aust. J. Agric. Res., 1969, 20, 347.
Effect of drinking-water temperature on heat balance and thermoregulatory responses in dairy heifers
Authors: Purwanto BP , Harada M , Yamamoto S
Published: November 2004

A study was made to determine the effect of heat dissipation from drinking water (8 kg at 10, 20, or 30�C) on the heat balance and thermoregulatory responses of 4 dairy heifers housed at 24, 29, and 34�C. No effect of drinking-water temperature on heat production or heart rate was found. Respiration rate, mean skin-surface temperature, and rectal temperature all decreased with decreasing drinking-water temperature. Rectal temperature reached a minimum 20 min after watering. The respiration rate, skin temperature, and rectal temperature returned to prior-to-watering values 120-180 min after watering. The cooling efficiency of drinking water was about 40%, and decreased at high environmental temperature, because the cooling potential was used initially in depressing heat loss responses. It is suggested that in order to eliminate excessive heat load, chilled drinking water could be effective during the night time when the environmental temperature is lowest.
A prolactin family paralog regulates reproductive adaptations to a physiological stressor
Authors: Ain Rupasri , Dai Guoli , Dunmore Judy H. , Godwin Alan R. , Soares Michael J.
Published: November 2004

Successful species develop strategies to optimize their reproductive performance. This optimization likely includes the evolution of genes that specifically permit reproduction in physiologically challenging conditions. The prolactin (PRL) family gene cluster is one of 25 mouse-specific gene clusters, the majority of which are associated with reproduction. A prevailing theme characterizing the PRL family is its connection with pregnancy and mechanisms controlling viviparity. PRL-like protein A (PLP-A) is one of 26 genes located within the PRL family locus. It is a nonclassical member of the PRL family (e.g., PLP-A does not use the PRL receptor) produced by trophoblast cells of the chorioallantoic placenta and acts on uterine natural killer cells. In this report, the biology of PLP-A has been investigated by generating mice with a PLP-A null mutation. Under standardized animal husbandry conditions, PLP-A possesses modest effects on reproductive performance. However, this same gene is critical for reproduction when mice are exposed to a physiological stressor. Wild-type mice exposed to hypobaric hypoxia during gestation readily adapt and maintain their pregnancies, whereas PLP-A null mutant mice fail to adapt, resulting in pregnancy failure. PLP-A contributes to hypoxia-induced adaptations critical to hemochorial placentation and thus nutrient flow to extraembryonic and embryonic tissues. The findings provide insights into species-specific reproductive adaptations.
Anaemia and iron deficiency during pregnancy in rural Bangladesh
Authors: Hyder SM Ziauddin , Persson Lars-Åke , Chowdhury Mushtaque , Lönnerdal Bo , Ekström Eva-Charlotte
Published: November 2004

Objective:

To study the prevalence of anaemia and its association with measures of iron deficiency (ID) among a group of pregnant women.

Design:

Cross-sectional survey.

Setting:

Pregnant women identified through house-to-house visits and participating in community-based antenatal care activities in a rural location of Mymensingh, Bangladesh.

Subjects:

The estimates are based on 214 reportedly healthy pregnant women in their second trimester. Information on socio-economic status and reproductive history were obtained through home visits and venous blood samples were collected at antenatal care centres. Haemoglobin concentration (Hb) was measured by HemoCue, serum ferritin (sFt) by radioimmunoassay and serum transferrin receptor (sTfR) by enzyme-linked immunosorbent assay methods. ID was defined as presence of either low sFt (<12 μg l−1) or high sTfR (>8.5 mg l−1).

Results:

The prevalence of anaemia (Hb <110 g l−1) was 50%, but severe anaemia (Hb >70 g l−1) was absent. Low sFt was observed in 42%, high sTfR in 25%, either low sFt or high TfR in 54% and both low sFt and high TfR in 13% of the pregnant women. Two out of three anaemic women had an indication of ID, which was present in 80% of women with moderate (Hb 70–99 g l−1) and 50% with mild (Hb 100–109 g l−1) anaemia. Four out of 10 non-anaemic women (Hb >110 g l−1) also had ID, but the prevalence was significantly lower than that observed in anaemic women (P=0.001).

Conclusions:

Despite the high prevalence of anaemia, severe cases were absent. The prevalence of ID increased at lower Hb. However, an increased prevalence was also found among women in the highest category of Hb.
MT1-MMP–dependent neovessel formation within the confines of the three-dimensional extracellular matrix
Authors: Chun Tae-Hwa , Sabeh Farideh , Ota Ichiro , Murphy Hedwig , McDonagh Kevin T. , Holmbeck Kenn , Birkedal-Hansen Henning , Allen Edward D. , Weiss Stephen J.
Published: November 2004

During angiogenesis, endothelial cells initiate a tissue-invasive program within an interstitial matrix comprised largely of type I collagen. Extracellular matrix–degradative enzymes, including the matrix metalloproteinases (MMPs) MMP-2 and MMP-9, are thought to play key roles in angiogenesis by binding to docking sites on the cell surface after activation by plasmin- and/or membrane-type (MT) 1-MMP–dependent processes. To identify proteinases critical to neovessel formation, an ex vivo model of angiogenesis has been established wherein tissue explants from gene-targeted mice are embedded within a three-dimensional, type I collagen matrix. Unexpectedly, neither MMP-2, MMP-9, their cognate cell-surface receptors (i.e., β3 integrin and CD44), nor plasminogen are essential for collagenolytic activity, endothelial cell invasion, or neovessel formation. Instead, the membrane-anchored MMP, MT1-MMP, confers endothelial cells with the ability to express invasive and tubulogenic activity in a collagen-rich milieu, in vitro or in vivo, where it plays an indispensable role in driving neovessel formation.
Pex7p translocates in and out of peroxisomes in Saccharomyces cerevisiae
Authors: Nair Devi M. , Purdue P. Edward , Lazarow Paul B.
Published: November 2004

Pex7p is the soluble receptor responsible for importing into peroxisomes newly synthesized proteins bearing a type 2 peroxisomal targeting sequence. We observe that appending GFP to Pex7p's COOH terminus shifts Pex7p's intracellular distribution from predominantly cytosolic to predominantly peroxisomal in Saccharomyces cerevisiae. Cleavage of the link between Pex7p and GFP within peroxisomes liberates GFP, which remains inside the organelle, and Pex7p, which exits to the cytosol. The reexported Pex7p is functional, resulting in import of thiolase into peroxisomes and improved growth of the yeast on oleic acid. These results support the “extended shuttle” model of peroxisome import receptor function and open the way to future studies of receptor export.
Gating Charges in the Activation and Inactivation Processes of the hERG Channel
Authors: Zhang Mei , Liu Jie , Tseng Gea-Ny
Published: November 2004

The hERG channel has a relatively slow activation process but an extremely fast and voltage-sensitive inactivation process. Direct measurement of hERG's gating current (Piper, D.R., A. Varghese, M.C. Sanguinetti, and M. Tristani-Firouzi. 2003. PNAS. 100:10534–10539) reveals two kinetic components of gating charge transfer that may originate from two channel domains. This study is designed to address three questions: (1) which of the six positive charges in hERG's major voltage sensor, S4, are responsible for gating charge transfer during activation, (2) whether a negative charge in the cytoplasmic half of S2 (D466) also contributes to gating charge transfer, and (3) whether S4 serves as the sole voltage sensor for hERG inactivation. We individually mutate S4's positive charges and D466 to cysteine, and examine (a) effects of mutations on the number of equivalent gating charges transferred during activation (za) and inactivation (zi), and (b) sidedness and state dependence of accessibility of introduced cysteine side chains to a membrane-impermeable thiol-modifying reagent (MTSET). Neutralizing the outer three positive charges in S4 and D466 in S2 reduces za, and cysteine side chains introduced into these positions experience state-dependent changes in MTSET accessibility. On the other hand, neutralizing the inner three positive charges in S4 does not affect za. None of the charge mutations affect zi. We propose that the scheme of gating charge transfer during hERG's activation process is similar to that described for the Shaker channel, although hERG has less gating charge in its S4 than in Shaker. Furthermore, channel domain other than S4 contributes to gating charge involved in hERG's inactivation process.
Characterization of nanomechanical and nanotribological properties of digital micromirror devices
Authors: Bhushan Bharat , Liu Huiwen
Published: November 2004

Digital micromirror devices (DMDs) are commercially used for digital projection displays. Adhesion/stiction due to contact between the spring tips and landing sites is a critical issue that affects the reliable operation of DMDs. In this study, an atomic force microscopy (AFM) methodology was used to perform nanoscale bending tests on the hinge of the DMD to measure the elastic modulus which is a very important factor in its design. Micromirror tilting measurements on the DMD chip were performed to obtain the force required to tilt the micromirror. In addition, the adhesive force of the landing sites, and the surface roughness, adhesive force and coefficient of friction of various films, were measured. These data were used to understand the relationship between the interface material properties and propensity for micromirror stiction occurrence in various DMDs.
The dominant role of adsorbed fluid layers on the polar surfaces of ZnO in ambient
atmospheric conditions
Authors: Fryar James , McGlynn Enda , Henry Martin O , Cafolla A Anthony , Hanson Claire J
Published: November 2004

Polar ZnO surfaces with O- and Zn-termination were studied with atomic and lateral force
microscopy and force curves. Adsorbed fluid layers on both surfaces are found to dominate
their adhesion properties in air. The hydrophilic O-surface has a substantially
thicker adsorbed layer and larger residual particle densities. Our data suggest that
different preparation is required for the two surfaces before use in epitaxy, and
may resolve some contradictions in the literature. The data also indicate that
adsorbed fluid layers may be important in the growth of certain ZnO nanostructures.
Effectiveness of Naltrexone in a Community Treatment Program
Authors: Killeen Therese K. , Brady Kathleen T. , Gold Paul B. , Simpson Kit N. , Faldowski Richard A. , Tyson Clare , Anton Raymond F.
Published: November 2004

Objective: In several large, well‐designed, randomized, double‐blind studies, the opiate antagonist naltrexone demonstrated efficacy in the treatment of alcohol dependence. Specifically, when combined with certain psychosocial therapies, naltrexone reduces the number of drinking days, heavy drinking, and time to relapse to alcohol use in alcohol‐dependent individuals. Whether this efficacy can be generalized to individuals who have alcohol use disorders and present for treatment at front‐line community treatment programs has not been well established.

Methods: A total of 145 patients who presented for treatment at a rural community substance abuse treatment center were randomized to receive naltrexone 50 mg daily plus usual program treatment (n= 54), placebo plus usual treatment (n= 43), or usual treatment alone (n= 48) for 12 week. A total of 133 participants had at least one follow‐up visit. Primary outcome measures included percent days drinking, average drinks per drinking day, average drinks per day, heavy drinking days (four or more for women and six or more for men), and time to first heavy drinking day. Secondary measures included changes in serum biological markers (alkaline phosphatase, alanine transaminase, aspartate transaminase, and γ‐glutamyltransferase), craving, and psychosocial functioning.

Results: In the intention‐to‐treat analysis, there were no between‐group differences for any of the primary drinking outcomes at 12 weeks. In post hoc exploratory analyses, the entire sample of participants was divided into two new groups: (1) people who drank during the 2 weeks before the start of medication (entry drinkers) and (2) people who did not drink during this interval (entry abstainers). Entry abstainers were at an advantage at study entry in that they were significantly more likely to have an inpatient hospitalization immediately before entry into outpatient treatment. Mixed‐model analysis of variance revealed a main effect for entry group at the 12‐week treatment endpoint on the primary outcome measures of percent days drinking, average drinks per drinking day, average drinks per day, heavy drinking days, and time to first heavy drinking day. Participants in any of the randomized groups who were entry abstainers had significantly better improvement on all of the primary outcome measures. The abstainer groups that were randomized to placebo and usual treatment had significantly better outcomes than the entry drinkers in those perspective groups. However, for the naltrexone‐treated group, entry drinkers and entry abstainers had similar improvement in drinking‐related outcomes.

Conclusions: These data suggest that naltrexone may offer particular benefit to patients who continue to drink during the early stages of the trial as compared with those who have achieved abstinence before treatment entry.
Perceptual Learning in Detoxified Alcoholic Men: Contributions From Explicit Memory, Executive Function, and Age
Authors: Fama Rosemary , Pfefferbaum Adolf , Sullivan Edith V.
Published: November 2004

Background: Visuospatial and visuoperceptual deficits have consistently been observed in detoxified alcoholics; however, the severity of impairment varies with test and task type. Identifying the component processes and factors that underlie a particular deficit may reveal why some visuospatial and visuoperceptual tasks are more compromised than others and may lead to the specification of neural systems that are particularly vulnerable in alcoholism.

Methods: We examined visuoperception and perceptual learning with a picture fragment identification task in 51 recently detoxified nonamnesic alcoholic men (aged 29–66 years) compared with 63 normal control men (aged 21–70 years). Executive function and explicit declarative memory were also assessed.

Results: Despite deficits in the primary components of visuoperception and explicit memory for visuospatial stimuli, the alcoholics showed normal perceptual learning. Although the alcoholics and controls performed at comparable levels on the perceptual learning task, multiple regression analyses indicated that the factors accounting for perceptual learning variance differed between and within groups. Visuoperceptual abilities consistently predicted perceptual learning in the control subjects but not the alcoholic subjects. Explicit memory contributed to perceptual learning performance in both the alcoholic and control groups. Frontal executive ability consistently predicted perceptual learning in the alcoholic subjects, but it had predictive ability only in the control subjects as time elapsed. Age was significantly correlated with perceptual learning performance in both groups. Lifetime alcohol consumption, but not alcoholism duration, was an independent predictor of 1‐hr perceptual learning.

Conclusions: These correlational analyses suggest that controls invoke basic visuospatial processes to perform a perceptual learning task, whereas alcoholics invoke higher‐order cognitive processes (i.e., frontal executive systems) to perform the same task at normal levels. Use of more demanding cognitive systems by the alcoholics may be less efficient and more costly to processing capacity than those invoked by controls.
Magnesium Treatment of Primary Alcohol‐Dependent Patients During Subacute Withdrawal: An Open Pilot Study With Polysomnography
Authors: Hornyak Magdolna , Haas Peter , Veit Johannes , Gann Horst , Riemann Dieter
Published: November 2004

Background: Sleep electroencephalogram alterations and insomnia complaints persist after alcohol withdrawal in dependent patients and are considered strong predictors of relapse. Although disturbances of magnesium household due to alcohol consumption are well known, the relationship of magnesium metabolism and sleep disturbances has not been investigated in this patient group. We conducted an open pilot study to evaluate the effects of magnesium treatment on the sleep of primary alcohol‐dependent patients during subacute withdrawal.

Methods: Patients were treated with 30 mmol magnesium daily over 4 weeks. Eleven of the 14 included patients were evaluated. Patients were free of any kind of psychotropic medication or other substances known to influence sleep. Polysomnographic recordings with monitoring of periodic leg movements in sleep (PLMS) were performed for two consecutive nights 2 weeks after acute withdrawal (baseline) and 4 weeks later at the end of the treatment period. After the baseline polysomnography, patients were investigated by the magnesium loading test to verify magnesium depletion.

Results: We found a significant decrease of sleep onset latency from 40.6 to 21.7 min (p= 0.03) and a significant improvement of subjective sleep quality, as assessed by the Pittsburgh Sleep Quality Index, from 8.1 to 5.8 (p= 0.05) during magnesium treatment. Changes in PLMS indices revealed two subgroups of patients: one with an increase of PLMS from 30.7 to 39.4 per hour of sleep (n= 4) and the other one with a decrease of PLMS from 8.9 to 2.1 per hour of sleep (p= 0.04). Patients with PLMS decreases seemed to have a more favorable prognosis: total sleep time, γ‐glutamyltransferase, carbohydrate‐deficient transferrin, and Beck Depression Inventory scores improved significantly during treatment in this group. The magnesium loading test revealed a magnesium deficiency in only one patient, five patients showed normal retention values, and the remaining five patients had an increased magnesium excretion, indicating a possible continued renal magnesium loss during abstinence.

Conclusions: The results of this study should be interpreted with caution, because no control group with placebo was investigated. Both subjective and, partly, objective parameters of sleep improved during the 4‐week study period. Further research is needed to clarify the relationship of magnesium metabolism and sleep alterations.