Whole Period Of Growth Research Articles

Novel signals and polygenic score for height are associated with pubertal growth traits in Southwestern American Indians.

Most genetic variants associated with adult height have been identified through large genome-wide association studies (GWASs) in European-ancestry cohorts. However, it is unclear how these variants influence linear growth during adolescence. This study uses anthropometric and genotypic data from a longitudinal study conducted in an American Indian community in Arizona between 1965-2007. Growth parameters (i.e. height, velocity, and timing of growth spurt) were derived from the Preece-Baines growth model, a parametric growth curve fitted to longitudinal height data, in 787 participants with height measurements spanning the whole period of growth. Heritability estimates suggested that genetic factors could explain 25% to 71% of the variance of pubertal growth traits. We performed a GWAS of growth parameters, testing their associations with 5 077 595 imputed or directly genotyped variants. Six variants associated with height at peak velocity (P < 5 × 10-8, adjusted for sex, birth year and principal components). Implicated genes include NUDT3, previously associated with adult height, and PACSIN1. Two novel variants associated with duration of growth spurt (P < 5 × 10-8) in LOC105375344, an uncharacterized gene with unknown function. We finally examined the association of growth parameters with a polygenic score for height derived from 9557 single nucleotide polymorphisms (SNPs) identified in the GIANT meta-analysis for which genotypic data were available for the American Indian study population. Height polygenic score was correlated with the magnitude and velocity of height growth that occurred before and at the peak of the adolescent growth spurt, indicating overlapping genetic architecture, with no influence on the timing of adolescent growth.

Extracellular vesicles involved in growth regulation and metabolic modulation in Haematococcus pluvialis

BackgroundMicroalgae-derived extracellular vesicles (EVs), which transfer their cargos to the extracellular environment to affect recipient cells, play important roles in microalgal growth and environmental adaptation. And, they are also considered as sustainable and renewable bioresources of delivery nanocarrier for bioactive molecules and/or artificial drug molecules. However, their molecular composition and functions remain poorly understood.ResultsIn this study, isolation, characterization, and functional verification of Haematococcus pluvialis-derived EVs (HpEVs) were performed. The results indicated that HpEVs with typical EV morphology and size were secreted by H. pluvialis cells during the whole period of growth and accumulated in the culture medium. Cellular uptake of HpEVs by H. pluvialis was confirmed, and their roles in regulation of growth and various physiological processes of the recipient cells were also characterized. The short-term inhibition of HpEV secretion results in the accumulation of functional cellular components of HpEVs, thereby altering the biological response of these cells at the molecular level. Meanwhile, continuously inhibiting the secretion of HpEVs negatively influenced growth, and fatty acid and astaxanthin accumulation in H. pluvialis. Small RNA high-throughput sequencing was further performed to determine the miRNA cargoes and compelling details in HpEVs in depth. Comparative analysis revealed commonalities and differences in miRNA species and expression levels in three stages of HpEVs. A total of 163 mature miRNAs were identified with a few unique miRNAs reveal the highest expression levels, and miRNA expression profile of the HpEVs exhibited a clear stage-specific pattern. Moreover, a total of 12 differentially expressed miRNAs were identified and their target genes were classified to cell cycle control, lipid transport and metabolism, secondary metabolites biosynthesis and so on.ConclusionIt was therefore proposed that cargos of HpEVs, including miRNA constituents, were suggested potential roles in modulate cell physiological state of H. pluvialis. To summarize, this work uncovers the intercellular communication and metabolism regulation functions of HpEVs.

Adolescent Growth Spurt and Type 2 Diabetes Risk in Southwestern American Indians.

Early puberty onset is associated with higher risk of diabetes, but most studies have not accounted for childhood factors that may confound the association. Using data from a study conducted in an Indigenous community in Arizona (1965-2007), we examined associations of timing and velocity of the adolescent growth spurt with type 2 diabetes, and whether these associations are mediated by childhood body mass index and insulinemia. Adolescent growth parameters were derived from the Preece-Baines growth model, a parametric growth curve fitted to longitudinal height data, for 861 participants with height measurements spanning the whole period of growth. In males, older age at take-off, age at peak velocity, and age at maturation were associated with decreased prevalence of diabetes (odds ratio (OR)= 0.43 per year, 95% confidence interval (CI): 0.27, 0.69; OR= 0.50, 95% CI: 0.35, 0.72; OR= 0.58, 95% CI: 0.41, 0.83, respectively), while higher velocity at take-off was associated with increased risk (OR= 3.47 per cm/year, 95% CI: 1.87, 6.42) adjusting for age, birth year, and maternal diabetes. Similar results were observed with incident diabetes. Our findings suggest that an early and accelerated adolescent growth spurt is a risk factor for diabetes, at least in males. These associations are only partially explained by measures of adiposity and insulinemia.

Soil-pit Method for Distribution and Leaching Loss of Nitrogen in Winter Wheat’s Soil, Weishan Irrigation District

Unreasonable application of irrigation and fertilizer will cause the waste of water and nitrogen and environmental pollution. In this paper, a series of soil-pit experiments were carried out to study the distribution and leaching loss of nitrogen in winter wheat’s soil. The results showed that NO3- concentration at 20-80cm depth mainly responded to fertilizer application at the beginning of field experiment, but the amount of irrigation became the dominant factor with the growth of winter wheat. It is noteworthy that the distribution of NO3- was mainly affected by the amount of fertilizer applied at the depth of 120-160cm in the whole period of growth of winter wheat. The accumulation position of NH4+ was deepened as the amount of irrigation increased, however, the maximum aggregation depth of ammonium nitrogen was no more than 80cm owing to its poor migration. It can be concluded that the influence of irrigation amount on the concentration of NH4+ in soil solution was more obvious than that of fertilizer. Compared with fertilizer, the amount of irrigation played a leading role in the utilization ratio of nitrogen and the yield of winter wheat. In summary, the best water and fertilizer treatment occurred in No.3 soil-pit, which meant that the middle amount of water and fertilizer could get higher wheat yield and less nitrogen leaching losses in the study area.

A universal model of ontogenetic growth.

The assumption that a single growth equation can be used to describe all biological objects on different organizational levels and a dimensional analysis are applied in order to substantiate universal model of ontogenetic growth. This model (the mass of a growing organism is a power function of time) is valid only in the initial period of growth. For the whole period of growth, a generalization of the model is advanced; it provides the same accuracy as previously known models of quantitative description of kinetic curves. Within the scope of the developed model, a number of interesting results related to allometry and biological time are obtained.

Measured and modeled interactive effects of potassium deficiency and water deficit on gross primary productivity and light-use efficiency in Eucalyptus grandis plantations.

Global climate change is expected to increase the length of drought periods in many tropical regions. Although large amounts of potassium (K) are applied in tropical crops and planted forests, little is known about the interaction between K nutrition and water deficit on the physiological mechanisms governing plant growth. A process-based model (MAESPA) parameterized in a split-plot experiment in Brazil was used to gain insight into the combined effects of K deficiency and water deficit on absorbed radiation (aPAR), gross primary productivity (GPP), and light-use efficiency for carbon assimilation and stem biomass production (LUEC and LUEs ) in Eucalyptus grandis plantations. The main-plot factor was the water supply (undisturbed rainfall vs. 37% of throughfall excluded) and the subplot factor was the K supply (with or without 0.45 mol K m(-2 ) K addition). Mean GPP was 28% lower without K addition over the first 3 years after planting whether throughfall was partly excluded or not. K deficiency reduced aPAR by 20% and LUEC by 10% over the whole period of growth. With K addition, throughfall exclusion decreased GPP by 25%, resulting from a 21% decrease in LUEC at the end of the study period. The effect of the combination of K deficiency and water deficit was less severe than the sum of the effects of K deficiency and water deficit individually, leading to a reduction in stem biomass production, gross primary productivity and LUE similar to K deficiency on its own. The modeling approach showed that K nutrition and water deficit influenced absorbed radiation essentially through changes in leaf area index and tree height. The changes in gross primary productivity and light-use efficiency were, however, driven by a more complex set of tree parameters, especially those controlling water uptake by roots and leaf photosynthetic capacities.

The growth and the development of gastro-soleus contracture in cerebral palsy

Introduction: The development of contractures in children with spastic cerebral palsy is an important clinical as well as scientific issue. A common model for the development of contractures suggests that increased muscle tone shortens muscles, which leads to reduced growth of sarcomeres and tighter noncontractile muscle and tendon tissue. However, the spasticity is not the only factor influencing the contracture development. Based on our clinical observation we hypothesize that the body growth might play a key role in development of gastrocnemius contracture. Patients/materials and methods: We performed a retrospective cross-sectional analysis of 3D gait data of 244 children (385 legs) with spastic diplegic CP and equinus gait. Children were subdivided according to age into 6 subgroups (5–6, 7–8, 9–10, 11–12, 13–14 and 15–18 years) to show the changes during the whole period of growth. The height of all the participants at each visit was recorded. A formerly trained Generalized Dynamic Neuronal Network (GDNN) [1], a reliable method of automatic gait pattern recognition and classification, was used to discriminate between dynamic and fixed contracture of gastro-soleus muscle based on the ankle and knee kinematics and moments. The Spearman correlation coefficient was used to show the relationship between the growth and gastro-soleus contracture development. Results: The relative increase of fixed contracture of the gastrosoleus muscle between the age groups correlates positively with the relative increase in height (r=0.9; p<0.05). Therefore, the development of equinus contracture is tightly correlated with growth velocity in children with diplegic spastic CP. Discussion & conclusions: The range of ankle motion is decreasing during childhood [2]. It might sound contradictory but the spasticity of gastrosoleus muscle is decreasing between the ages 6–12 [3] as well. It seems that contracture development is not only moderated by spasticity and the reduction in tone does not prevent the development of contractures in CP [4]. We proved that the development of equinus contracture is tightly correlated with growth velocity in CP. Thereforewewould like to stress the growth spurt as an important period for contracture development as well as prevention.

Housing of growing rabbits in individual, bicellular and collective cages: growth performance, carcass traits and meat quality

During growth (from 27 to 75 days of age), 384 rabbits were kept in different types of wire-net cages: 72 individual cages (72 rabbits; 10 animals/m2), 48 bicellular cages (96 rabbits; 2 rabbits/cage; 18 animals/m2) and 24 collective cages (216 rabbits; 9 rabbits/cage; 18 animals/m2). The rabbits housed in individual cages showed higher daily weight gain both during the fattening period (from 52 to 75 days of age) and during the whole period of growth (43.0 v. 41.8 and 41.5 g/day; P < 0.05), and they had a higher final live weight at 75 days of age (2678 v. 2619 and 2602 g; P < 0.05) compared with the rabbits in the bicellular and collective cages, respectively. Rabbits in individual cages ingested more feed (133 v. 127 and 126 g/day; P < 0.01), but the feed conversion did not differ significantly among rabbits housed in the three types of cages. At slaughter, the carcass traits and meat quality were weakly affected by the housing system. The transport losses were higher in rabbits kept in individual and bicellular cages compared with those reared in collective cages (3.1% and 2.9% v. 2.2%; P < 0.01). In rabbits kept in individual cages, the hind leg muscle to bone ratio was higher (6.35 v. 6.19 and 5.91; P < 0.05) compared with the bicellular and collective cages, respectively. The pH and colour of the longissimus lumborum did not change with the housing system, while the b* index of the biceps femoris was lower (3.04 and 3.32 v. 4.26; P < 0.001) in the rabbits kept in individual and bicellular cages, respectively, than in those kept in collective cages. In conclusion, the rabbits housed in individual cages showed higher daily growth than rabbits kept in bicellular or collective cages, but they had a similar feed conversion and carcass quality. Differently, neither in vivo performance nor slaughter results differed among the rabbits kept in bicellular cages or in collective cages. The meat colour may be affected by the housing system, but to an extent that is hardly perceivable by the final consumer.

Visible injury and growth inhibition of black pine in relation to oxidative stress in industrial areas

The objective of our study was to investigate the major reasons for the different growth and visible injury on the needles of black pine growing in Ulsan and Yeocheon industrial complex areas, South Korea. After 12 years of growth, we collected climatic and air pollutant data, and analyzed soil properties and the physiological characteristics of black pine needles. Annual and minimum temperatures in Ulsan were higher than those in Yeocheon from 1996 to 2008. Ozone () was the pollutant in greatest concentration in Yeocheon, and whereas the concentration in most areas decreased gradually during the whole period of growth, concentration in Yeocheon has increased continuously since 1999, where it was the highest out of four areas since 2005. Total nitrogen and cation exchange capacity in Yeocheon soil were significantly lower than those of Ulsan. The average growth of black pine in Yeocheon was significantly smaller than that in Ulsan, and the growth of damaged trees represented a significant difference between the two sites. Photosynthetic pigment and malondialdehyde content and antioxidative enzyme activity in the current needles of black pine in Yeocheon were not significantly different between damaged and healthy trees, but in 1-year-old needles, there were significant differences between damaged and healthy trees. In conclusion, needle damage in Yeocheon black pine can be considered the result of long-term exposure to oxidative stress by such as or , rather than a difference in climatic condition or soil properties, and the additional expense of photosynthate needed to overcome damage or alleviate oxidative stress may cause growth retardation.

Plant availability of soil selenate additions and selenium distribution within wheat and ryegrass

Selenate fertilization is an effective way to secure selenium (Se) nutrition in Se-poor areas but the cycling of the added selenate in the soil-plant system requires further clarification. We examined the Se uptake efficiency of wheat and ryegrass and Se distribution within these plants in two pot experiments. The behaviour of added selenate in a sand soil under wheat was monitored by sequential extractions during a ten-week growing period. In addition, the relationship between Se uptake of ryegrass and the salt extractable and ligand exchangeable Se in a sand and silty clay soil were studied. The added selenate remained mainly salt soluble in the soil throughout the monitoring. Se uptake by wheat comprised 12% of the soluble Se pool in soil and extended over the whole period of growth. In wheat, over 50% of Se accumulated in grains. The Se uptake of ryegrass comprised, on average, 40% of the soil salt soluble Se. In ryegrass, over 80% of the Se accumulated in roots. The distribution pattern of Se in plants can clearly have a major influence on both the Se cycle in soil and the nutritional efficiency of Se fertilization. The simple salt extraction showed fertilization-induced changes in the soluble soil Se pool, whereas the ligand exchangeable Se fraction reflected the difference in the nonlabile Se status between the two soils.

The effect of vitamin A supplementation on postnatal adipose tissue development of lambs1

Vitamin A (retinoic acid) is known to be an adipogenic factor influencing both in vitro and in vivo cell development. This study aimed to determine its effect on lamb adipose tissue development during the early phase of postnatal development until 100 d of age. Male lambs (n = 24) of the Rasa Aragonesa breed were used. At birth, lambs were assigned to 1 of 2 experimental groups: 1) the control (C) group, which received feed without vitamin A supplementation, and 2) the vitamin A (V) group, which received a supplement of 500,000 IU/animal twice per week from birth to slaughter. The effect of vitamin A supplementation was studied at 16.8 +/- 0.35 kg of BW (58 +/- 0.7 d of age) and at 27.8 +/- 0.78 kg of BW (101 +/- 6.5 d of age). The variables of lamb growth, carcass, LM area, and lipid content were analyzed. To study adipose tissue development, the amount of adipose tissue accumulated, the size and number of adipocytes, and lipogenic enzyme activities (glycerol 3-phosphate dehydrogenase, fatty acid synthase, and glucose 6-phosphate dehydrogenase) of the omental, perirenal, and s.c. depots were quantified. Results showed that vitamin A supplementation had no influence on growth, carcass variables, LM area, and lipid content during lamb growth but that the number of adipocytes in the perirenal depot was 30% greater in lambs of the V group (P < 0.05) and that these lambs had smaller adipocytes in the omental and perirenal depots (P = 0.06) at 28 kg of BW (101 d of age). These results suggest that the intake of this level of vitamin A during the whole period of growth of the lambs influenced the processes of hyperplasia and hypertrophy in the different adipose depots, depending on their degree of maturity.

Determination of volatile metabolites originating from mould growth on wall paper and synthetic media

Microbial volatile organic compounds (MVOCs) emitted from the mould species Penicillium expansum, P. chrysogenum, Aspergillus versicolor, A. fumigatus, A. niger and Cladosporium cladosporoides were analyzed by means of solid phase microextraction (SPME) and GCMS. The mould species were cultivated on the synthetic agar dichloran chloramphenicol (DG 18) and on wet wall paper. The production of MVOCs was monitored over several weeks to detect changes in the emission rates between the initial stage and later periods of growth. The cultivation on the synthetic agar resulted in MVOC patterns with a wide variety of signals. In contrast, the growth on wet wall paper led to changed MVOC patterns with less signals. The emission rates were drastically reduced. Components emitted by all six fungi species on wall paper were 2-pentanol and 2-pentanone. 1-Octen-3-ol was emitted by five fungi species. 2-Pentanol was only detected in considerable amounts during the first days of growth whereas 1-octen-3-ol had a more constant emission rate over the whole period of growth. On the basis of our studies some MVOCs could be proposed as specific for single fungi on wall paper, e.g. 1,3-dimethoxybenzene for A. versicolor and 2,4-pentandione for A. fumigatus.

Effect of Irrigation with Drainage water at Sorghum growth stages on salts accumulation and growth, yield of crop

This experiment was conducted at farm in garma city during atum season 2004 in silty loam texture, classified as Typic torrifluvent to study the effect of Irrigation with Drainage water average 3.48 ds.m-1 at (Germenation stage T2, seedling stage T3, Tillering stage T4 flowerd and yield formation T5and at whole growth period of yield T6) and in comparison with Irrigation with river water 1.25 ds.m-1 was used as a control T1 on salts accumulation and growth and production of Sorghum (variety Ankath). Result showed that the River water was suitable water and the drainage water was non suitable for Irrigation, also noticed that the Irrigation with drainage water at whole period of growth and Irrigated at flower and yield formation caused significantly increaseing in salt accumulation and SAR [ 8.17 ds.m-1, 5.03 (m mol. L-1)1/2 ] [ 5.93 ds.m-1, 4.36 (m mol. L-1)1/2 ] on soil respectively compared with Irrigation river water and Irrigation with saline Drainage water at stages germenation, seedling, Tillering, [4.33 ds.m-1, 2.64 (m mol. L)1/2 ], [3.77 ds.m-1, 3.57 (m mol. L-1)1/2 ] [3.13 ds.m-1, 3.45 (m mol. L-1)1/2] [3.39 ds.m-1, 3.38 (m mol. L-1)1/2], also the Irrigation with River water and Saline Drainage water at stages germenation, Seedling, Tillering caused Leaching of salts from surface layer and getting accumulation salts at Irrigated with saline Drainage water at whole period of growth and flowering and yield formation compared with soil salinity soil before farming (4.9 ds.m-1). The Irrigated with saline Drainage water at whole period of growth, at flowering and yield formation and Tillering caused significantly decreased on weight of seed, dry weight and plant high (55.93 gm, 229.2 gm, 113.83 cm), (67.60 gm, 308.1 gm, 129.22 cm), (73.87 gm, 306.2 gm, 132.55 cm) respectively compared with Irrigated River water (171.9 gm, 421.3 gm, 141.52 cm).

Raw Pea (Pisum sativum), raw Faba bean (Vicia faba var. minor) and raw Lupin (Lupinus albus var. multitalia) as alternative protein sources in broiler diets

The ban of the meat and bone meal for entering animal diets and the concern of transgenic feeds poses a challenge to animal nutritionists in Europe. The challenge is to find homegrown protein-rich feedstuffs, making sure no antinutritional factors are present which could interfere in the animals’ performance. The raw Pea (Pisum sativum) (RP), raw Faba bean (Vicia faba, variety minor) (RFb) and raw Lupin (Lupinus albus, variety multitalia) (RL) were evaluated as alternative protein sources into broiler diets. Six hundred thirty 1d-old Ross male chicks, Marek vaccinated, were randomly assigned to seven dietary treatments (5 pens per treatment/18 birds per pen). Chicks were floor housed, ad libitum fed isocaloric and isonitrogenous diets and had free access to water. Artificial light was provided 10 h/d. The bulk of the base diet (control diet) was corn (48.7%, 56.6% and 57%), solvent-extracted soybean meal (42.8%, 37.3% and 33.4%), corn oil (4.4%, 5.2% and 6.3%), plus synthetic amino acids, minerals, trace minerals and vitamins, respectively for the 1-10d-old, 11-28d-old and 29 to 42d-old growing periods. The RP, RFb and RL entered diets in substitution of the soybean and corn according to the cost optimization (P100, Fb100 and L100, respectively for RP, RFb and RL) and at half of the optimized quantity (RP50, RFb50 and RL50, respectively for RP, RFb and RL). The amount used as fed basis for the higher level of inclusion were: P100: 350 g/kg for all diets; Fb100: 480 g/kg (1-10d-old) and 500 g/kg (11-42d-old); L100: 360 g/kg (1-10d-old) and 300 g/kg (11-42d-old). The average daily gain (ADG) were lower (P < 0.05) in the RP group compared to the control group. Over the whole period of growth, the RFb group had similar ADG compared to the control group and for both levels of inclusion, whereas reduced (P < 0.05) ADG were observed in the RL100 group. Reduced (P < 0.05) ADG were also observed for the RFb100 and the RL100 groups when calculated over the first three weeks of growth. Birds performance was improved (P < 0.05) in the RL50 group. No effects were observed on dressing percentage and breast and leg quarter cuts. The RFb and RL could represent valuable protein feeds in broilers diet formulation.

Effects of Copper on the Growth, Uptake and Distribution of Uptake in Roots and Shoots of Carrot Plants Treated with Copper Solutions by Either Root-Treatment or Foliar-Treatment

Effect of treatment of carrot plant with copper solutions have been investigated. The growth of plant as well as its uptake of copper and the distribution of this uptake between roots and shoots of the treated plants were followed in the study. Two types of treatment have been used: root-treatment and foliar- treatment. Copper solutions with concentrations of 0.3 - 7.6 ppm were used for root - treatment (200 nil batches repeated for 12 times over the whole period of growth) and for foliar treatment (50 ml batches repeated for 12 times over the whole period of growth). The root -treatment of the plants resulted in 10 - 63% reduction in the dry weight of plant while foliar - treatment resulted in 2 - 69% weight reduction. Comparing the two types of treatment (via determination of amounts of copper causing 50% growth inhibition) indicated a much higher effect of foliar - treatment over root - treatment on the growth of the plants and more obviously on the growth of the shoots. The concentration and total content of copper in the treated plants as well as in their roots and shoots increased with the increase of copper concentration in solutions used for either the root - treatment or the foliar-treatment. The copper content of the shoots of treated plants exceeded the content in their roots, and this was more so in the case of foliar - treatment.

Cannabinoid level in the leaves as a tool for the early discrimination of cannabis chemiovariants

One hundred and seventy-six plants of 22 different lots of Cannabis sativa L., grown at the Botanical Garden of Siena (Italy) were chromatographically analysed in order to define the cannabinoid content in their leaves. The content of the major cannabinoids, Δ 9-tetrahydrocannabinol, cannabidiol, cannabinol and cannabichromene, determined weekly in vegetative and floral leaves enabled the determination of the chemical types of the plants, according to Turner's classification. The plants were easily distinguishable in drug, intermediate and fiber types. The cannabinoid characteristic of each type remains predominant, as compared with the other cannabinoids, throughout the whole period of growth, including the floral stage and after harvesting. On this basis, the predominant concentration of a specific cannabinoid can be used reliably for forensic application concerning drug-suspected material in very young plants.

Accumulation of calcium, magnesium, potassium and sodium with growth of individual leaves, petioles and stems of cucumber plants

Abstract Accumulation of Ca, Mg, K and Na in each individual leaf, petiole and stem of the cucumber plant (Cucumis sativus L. cv. Kasairaku) was investigated in relation to the growth of these organs under water culture condition. Growth of each individual organ followed a sigmoidal curve showing two distinctive phases, the exponential and stationary phases. Accumulation patterns of these major cations showed a elose relationship with the growth characteristics of the organs. 1) Leaf Although the rate of accumulation of the cations declined during the stationary phase of growth, both Ca and Na accumulated in all the leaves throughout the whole period of growth. A higher Ca content was observed in the older leaves while the younger leaves showed a higher Na content. Mg and K accumulated during the exponential phase, whereas no appreciable accumulation was observed during the stationary phase. 2) Petiole and stem. Accumulation of Ca, Mg and Na continued throughout the whole period of growth. No deeline in t...

The Supply of Water and Solutes by Phloem and Xylem to Growing Fruits of Yucca flaccida Haw

AbstractAnalyses of successively collected fractions of phloem exudate of Yucca flaccida, and of Yucca fruits picked at various stages of growth, together with experiments on transpiration from fruits, have led to the following conclusions: During fruit growth potassium, sodium, magnesium, phosphorus compounds, and nitrogenous substances are delivered to the fruit by both the xylem and the phloem. These solutes move also easily in radial direction between the xylem and phloem part of the vascular bundles. Actually they can be regarded as constituents of one stream of nutrients. The overall efficiency of conversion of vascular‐fluid dry matter into mature‐fruit dry matter is approximately 61 %. During its whole period of growth the fruit transpires an amount of water vapour of at least 6 times its own mature fresh weight. Estimates could be made for the relative contributions of xylem and phloem in the delivery of fruit constituents. 18% of the water imported by the fruit during its growth had a phloem, 82 % a xylem origin; 89% is transpired, 11 % retained as a fruit constituent. At least 94 % of the dry matter, 69% of the potassium, 56% of the magnesium, 26% of the phosphorus, and 7% of the calcium of the average fruit have been delivered by the phloem. The translocation of nitrogenous substances occurs probably partly in a more indirect way with temporary storage in inflorescence parenchyma.

Food efficiency in relation to estimated growth of body components in cattle

SUMMARYA model is proposed to establish a functional relationship between food intake, weight gain and body composition during growth, based on the differential energy requirements for fat, fat-free tissues and contents of the digestive tract. If constant specific nutrient requirements are assumed for fat and fat-free tissues, these requirements can be directly estimated from changes in food intake and body composition during growth. By introducing an allometric function relating changes in fat-free tissue to changes in body weight, the model is extended to include situations where direct measures of body composition are not available. This enabled the model to be fitted to data on food intake, body weight and growth rate up to 2 years of age in Friesians and Jerseys fed ad libitum on a complete diet. The nonlinear model is contrasted with a linear relationship where food intake i s related to body weight and weight gain. The linear model was unable to account for the changes in food intake over the whole period of growth. The non-linear model allowed a gradual decline n i maintenance requirements per unit weight and indicated an increase in the net conversion coefficient of food into gain, consistent with an increase from early to late growth in proportion of fat deposited.For the period studied the Jerseys were less efficient in transforming food into weight gain than Friesians. On the non-linear model, about half of the difference was attributable to the higher metabolic rate per unit weight of Jerseys, the remainder to poorer utilization of nutrients for weight gain. If, as the model indicated the conversion coefficients of food into body constituents were the same in the two breeds, the difference in efficiency may be attributable to a higher proportion of fat in the overall gain of Jerseys. The pattern of estimated fat deposition also differed in the two breeds with Jerseys appearing to be less mature in fat percentage at all stages.

Fungal lipids. II. Effects of varying concentration of nitrogen in the medium and incubation period on the chemical composition of lipids of Pythium irregulare Buisman.

AbstractEffects of varying the concentration of nitrogen in the medium and the incubation period on the chemical composition of lipids of Pythium irregulare Buisman were studied. In general, with low C/N ratios, the growth of mycelium and the lipid synthesis were found to increase up to the eleventh day of incubation after an initial lag period of five days. Thereafter only slight changes were observed. The fatty acid composition with low C/N ratios showed a considerable variation throughout the growth period. With high C/N ratios, the lipid content continued to increase during the whole period of growth. During this phase of growth, a rapid synthesis of triglycerides along with a marginal increase in the polar fraction was observed.In all the non‐polar lipid classes, oleic and palmitic were the major fatty acid components. Free fatty acid fractions comprised mainly of palmitic, oleic and arachidic acids. In all polar lipid fractions, except phosphatidyl choline and phosphatidic acids, oleic and palmitic were the principal acids. By argentation thin‐layer chromatography, eight mixed triglyceride classes were observed.