Anatomical adjustment of mature leaves of sycamore maple (Acer pseudoplatanus L.) to increased irradiance

Trees regenerating in the understory respond to increased availability of light caused by gap formation by undergoing a range of morphological and physiological adjustments. These adjustments include the production of thick, sun-type leaves containing thicker mesophyll and longer palisade cells than in shade-type leaves. We asked whether in the shade-regenerating tree Acer pseudoplatanus, the increase in leaf thickness and expansion of leaf tissues are possible also in leaves that had been fully formed prior to the increase in irradiance, a response reported so far only for a handful of species. We acclimated potted seedlings to eight levels (from 1 to 100%) of solar irradiance and, in late summer, transferred a subset of them to full sunlight. Within 30 days, the shaded leaves increased leaf mass per area and became thicker mostly due to elongation of palisade cells, except for the most shaded individuals which suffered irreversible photo-oxidative damage. This anatomical acclimation was accompanied by partial degradation of chlorophyll and a transient decline in photosynthetic efficiency of PSII (Fv/FM). These effects were related to the degree of pre-shading. The Fv/FM recovered substantially within the re-acclimation period. However, leaves of transferred plants were shed significantly earlier in the fall, indicating that the acclimation was not fully effective. These results show that A. pseudoplatanus is one of the few known species in which mature leaves may re-acclimate anatomically to increased irradiance. This may be a potentially important mechanism enhancing utilization of gaps created during the growing season.

Ethanol consumption during gestation promotes placental alterations in IGF-1 deficient mice

Background: During pregnancy, the placenta is an extremely important organ as it secretes its own hormones, e.g. insulin-like growth factor 1 (IGF-1), to ensure proper intrauterine fetal growth and development. Ethanol, an addictive and widely used drug, has numerous adverse effects during pregnancy, including fetal growth restriction (FGR). To date, the molecular mechanisms by which ethanol triggers its toxic effects during pregnancy, particularly in the placenta, are not entirely known. For this reason, a murine model of partial IGF-1 deficiency was used to determine ethanol alterations in placental morphology and AAH expression. Methods: Heterozygous (HZ, Igf1+/-) female mice were given 10% ethanol during 14 days as an acclimation period and throughout pregnancy. HZ female mice given water were used as controls. At gestational day 19, pregnant dams were sacrificed, placentas were collected and genotyped for subsequent studies. Results: IGF-1 deficiency and ethanol consumption during pregnancy altered placental morphology, and decreased placental efficiency and aspartyl/asparaginyl β-hydroxylase (AAH) expression in placentas from all genotypes. No differences were found in Igf1, Igf2, Igf1r and Igf2r mRNA expression in placentas from all groups. Conclusions: IGF-1 deficiency and ethanol consumption throughout gestation altered placental development, suggesting the crucial role of IGF-1 in the establishment of an adequate intrauterine environment that allows fetal growth. However, more studies are needed to study the precise mechanism to stablish the relation between both insults.

The Functional Association of ACQOS/VICTR with Salt Stress Resistance in Arabidopsis thaliana Was Confirmed by CRISPR-Mediated Mutagenesis

Clustered regularly interspaced palindromic repeat (CRISPR)-mediated mutagenesis has become an important tool in plant research, enabling the characterization of genes via gene knock-out. CRISPR genome editing tools can be applied to generate multi-gene knockout lines. Typically, multiple single-stranded, single guide RNAs (gRNAs) must be expressed in an organism to target multiple genes simultaneously; however, a single gRNA can target multiple genes if the target genes share similar sequences. A gene cluster comprising ACQUIRED OSMOTOLERANCE (ACQOS; AT5G46520) and neighboring nucleotide-binding leucine-rich repeats (NLRs; AT5G46510) is associated with osmotic tolerance. To investigate the role of ACQOS and the tandemly arranged NLR in osmotic tolerance, we introduced small insertion/deletion mutations into two target genes using a single gRNA and obtained transformant plant lines with three different combinations of mutant alleles. We then tested our mutant lines for osmotic tolerance after a salt-stress acclimation period by determining the chlorophyll contents of the mutant seedlings. Our results strongly suggest that ACQOS is directly associated with salt resistance, while the neighboring NLR is not. Here, we confirmed previous findings suggesting the involvement of ACQOS in salt tolerance and demonstrated the usefulness of CRISPR-mediated mutagenesis in validating the functions of genes in a single genetic background.

357 Effect of Energy Supplementation on Growth, Health, and Carcass Traits of Pasture-raised Lambs

Energy is often the most limiting nutrient in pasture diets. The effect of energy supplementation on the growth, health, and carcass traits of pasture-raised lambs was investigated. Seventy-nine Katahdin ram lambs were delivered to the Western Maryland Research & Education Center on June 15. After an 11-d acclimation period, lambs were allocated to two treatment groups based on age, weight, birth type, and FEC. Lambs in the PASTURE group (n = 40) rotationally grazed 2 ha of high quality, mixed pasture for 102 d. Lambs in the SUPPL group (n = 39) grazed similar pastures and were hand-fed a daily energy supplement (450 g of whole barley). The groups were handled bi-weekly to determine body weights, FAMACHA©, BCS, and dag scores. Individual fecal samples were collected upon arrival and at two additional time points. Lambs were ultrasound scanned on Sept 25 to determine carcass traits. Data were analyzed using the MIXED procedure of SAS, with statistical significance set at P ≤ 0.05. ADG varied considerably among weigh periods. Standard deviations were typically quite large, indicating wide variation in individual performance. Overall, the SUPPL lambs had higher ADG (P < 0.01), more backfat (P < 0.03), and higher BCS (P < 0.01) than the PASTURE lambs. There were no statistical differences in starting weight, ending weight, and loin depth. While internal parasites were not a problem during the study (only one lamb had a FAMACHA© score >4), PASTURE lambs had lower FEC (P < 0.05) on August 17 (240 ± 81 vs. 468 ± 80 epg). The value of additional gain (0.9 kg) would not have covered the cost of feed; however, four lambs were removed from the PASTURE group (due to death or failure to thrive) whereas only two lambs were removed from the SUPPL group. The study will be repeated in 2021 with similar lambs and protocol.

Exploration of The Lower Threshold of Iodine Intake In Southern Chinese Young Adults Based On ‘Overflow Theory’ In An Iodine Balance Study

Background: Appropriate iodine intake for adults is essential to reduce the prevalence of thyroid diseases, but there is little research data on iodine requirement of Chinese population. This study aimed to explore the iodine requirement of young adults to maintain a healthy status based on ‘overflow theory’.Methods: Iodine-balance experiment has been performed in this project. We conducted an 18-day study consisted of a 6-day acclimation period and 3 consecutive experimental stages in 37 Chinese healthy young adults (23 female and 14 male). Each stage was consumed for 4 days. Strictly-controlled low-iodine intake diets were provided for adults in the first period, an egg or 125mL milk was added in the second and third period, respectively. The dietary samples, 24-h urine specimens and faeces of volunteers were collected daily for assessment of iodine intake and excretion in volunteers.Results: Mean values of iodine intake (22.7±3.6, 35.1±3.7, and 52.2±3.8μg/d), excretion (64.7±13.9, 62.3±12.6, and 94.3±14.5μg/d) and iodine balance (-35.2±19.5, -21.0±19.8, and -33.5±26.9μg/d) were significantly different among three periods for male (P<0.001 for all); mean values of iodine intake (16.6±3.1, 29.7±2.7, and 48.0±2.7μg/d), and excretion (47.0±9.9, 55.5±8.1, and 75.7±12.4μg/d) were significantly different among three periods for female (P < 0.001 for all). No significant difference was observed among the 3 periods for female in the iodine balance (-30.5±9.3, -25.9±7.3, and -27.6±12.1μg/d). The linear regression equation of iodine excretion on iodine intake was Y=0.979X+37.04 (male) and Y=0.895X+31.48 (female). Compared with stage 2, iodine excretion increments in stage 3 had exceeded the iodine intake increment for men. The ratio of increment was 1.675 for male when the average iodine intake was 52.2μg/d in stage 3. When the iodine excretion increment equaled to the iodine intake increment, the daily iodine intake of men was 47.0μg.Conclusion: We have evaluated the iodine requirement of young adults in southern China based on overflow theory. Our results indicate the lower limit of iodine requirement for Chinese young men is 47.0μg/d. The trial was registered at www.chictr.org.cn as ChiCTR1800014877.

Digestible protein requirements for maintenance, growth, and efficiency of protein utilization in pacu (Piaractus mesopotamicus) juveniles: an exponential nitrogen utilization model

The present study aimed to estimate digestible protein (DP) requirements for maintenance and growth and assess the efficiency of protein utilization in pacu (Piaractus mesopotamicus) juveniles. A complete randomized design consisted of seven treatments, and five replicates (tanks) per treatment was used. After a one-week acclimation period, 350 pacu juveniles of 27.48 ± 1.8 g (initial average body weight - BW) were equally distributed among 35 tanks (10 fish per tank) of 450 L. Fish were fed with seven graded digestible protein levels (64.5, 111.8, 164.6, 217.1, 264.4, 316.2 and 369.5 g kg-1) three times a day until apparent satiation for 120 days. The monomolecular model parameters including nitrogen maintenance requirement (NMR) (37.76 mg BW0.67 kg-1 d-1), daily nitrogen deposition (ND) (194.8 mg BW0.67 kg-1 d-1), and protein intakes (based on metabolic BW) of 1638, 1902, and 2241 mg kg-1BW0.67 d-1 for 75, 80 and 85% maximum theoretical nitrogen retention (NRmaxT), respectively and the efficiency of protein utilization (529×10-6) were estimated through the relationship between nitrogen intake (NI) and ND. The digestible protein requirements for 75, 80, and 85% of NRmaxT were estimated as 187, 217, and 256 g kg-1 respectively by the monomolecular model based on the daily feed intake of 2% of live BW of pacu juveniles.

A Survey of Horse Selection, Longevity, and Retirement in Equine-Assisted Services in the United States

Little published information exists on the horses in equine-assisted services (EAS), particularly their selection, longevity, and retirement. The purpose of this study was to characterize horses and procedures used in EAS. A pilot survey was developed using focus group discussions and distributed to Professional Association of Therapeutic Horsemanship, International (PATH Intl) centers in Florida (n = 45, Part I) before further modification and distribution to members of PATH Intl., American Hippotherapy Association (AHA), eagala, and Certified Horsemanship Association (CHA) (n = 26,000, Part II). Response rates were 36% (Part I) and 0.7% (Part II). Centers report a median of 10 (Part I) or 9 (Part II) horses and ponies. Selection procedures included initial screening (Part I = 100%, Part II = 96%), pre-purchase or pre-donation exam (I = 64%, II = 60%), acclimation period (I = 100%, II = 84%), trial period (I = 91%, II = 90%), and other (II = 11%). Horses remained active in programs for less than a year to over 20 years with the greatest number working 7–10 (Part I) or 1–6 (Part II) yr. In Part I of the study, behavior (44%) was the leading cause of retirement followed by unsoundness (33%). In Part II, unsoundness was the highest ranked response followed by behavior. Behavior, soundness, and health emerged as key factors in horse selection and retirement. Future work should focus on investigating these issues at an individual horse level.

Age-Dependent Decline in Salinity Tolerance in a Euryhaline Fish

Euryhaline teleost fish are characterized by their ability to tolerate a wide range of environmental salinities by modifying the function of osmoregulatory cells and tissues. In this study, we experimentally addressed the age-related decline in the sensitivity of osmoregulatory transcripts associated with a transfer from fresh water (FW) to seawater (SW) in the euryhaline teleost, Mozambique tilapia, Oreochromis mossambicus. The survival rates of tilapia transferred from FW to SW were inversely related with age, indicating that older fish require a longer acclimation period during a salinity challenge. The relative expression of Na+/K+/2Cl− cotransporter 1a (nkcc1a), which plays an important role in hyposmoregulation, was significantly upregulated in younger fish after SW transfer, indicating a clear effect of age in the sensitivity of branchial ionocytes. Prolactin (Prl), a hyperosmoregulatory hormone in O. mossambicus, is released in direct response to a fall in extracellular osmolality. Prl cells of 4-month-old tilapia were sensitive to hyposmotic stimuli, while those of &gt;24-month-old fish did not respond. Moreover, the responsiveness of branchial ionocytes to Prl was more robust in younger fish. Taken together, multiple aspects of osmotic homeostasis, from osmoreception to hormonal and environmental control of osmoregulation, declined in older fish. This decline appears to undermine the ability of older fish to survive transfer to hyperosmotic environments.

Metagenomics and Metatranscriptomics Reveal Pathway of 3-Chloroaniline Degradation in Wastewater Reactors

Biological wastewater treatment systems are often affected by major shifts in influent quality, including the input of various toxic chemicals. Yet the mechanisms underlying adaptation of activated sludge process performance when challenged with a sustained toxin input have not been studied in a controlled and replicated experiment. Three replicate bench-scale bioreactors were subjected to a chemical disturbance in the form of 3-chloroaniline (3-CA) input over 132 days, following an acclimation period of 58 days, while three control reactors received no 3-CA input. The nitrification process was initially affected by 3-CA input; yet all three treatment reactors evolved to biologically degrade 3-CA within three weeks of the experiment, resulting in partial nitrification recovery. 16S rRNA amplicon sequencing revealed that ammonia oxidizers were initially impacted by 3-CA, and a new ammonia oxidizing community emerged with the onset of 3-CA degradation. Combining process and microbial community data from amplicon sequencing with potential functions gleaned from assembled metagenomics and metatranscriptomics data, 3-CA degradation was shown to likely occur via a phenol monooxygenase followed by ortho-cleavage of the aromatic ring. The relative abundance of genera Gemmatimonas, Saprospiraceae OLB8 and Taibaiella correlated significantly with 3-CA degradation. This study demonstrated the impact of a sustained stress on the activated sludge community and wastewater treatment process and its subsequent recovery. Using a combination of techniques in a controlled and replicated experiment, we showed that microbial communities can evolve degradative capacity following a sustained xenobiotic input, specific functions like nitrification can fully or partially recover and targeted culture-independent approaches can be used to elucidate the mechanisms of adaptation.

Evaluation of Whole Cottonseed Intake and in Situ digestibility in Beef Cattle

Whole cottonseed (WCS) is a byproduct of the cotton industry and can be used to supplement protein and energy to beef cattle. Given rapid industry changes in cotton variety use and their influence on WCS size, density, and quality characteristics, periodic evaluation of cotton byproducts is needed to determine appropriate feeding strategies. The objective of this study was to evaluate total WCS intake, gossypol intake, and digestibility of a widely-planted common variety of WCS in the southeastern U.S., Delta Pine 1646 (DP1646), compared with a low-gossypol variety, Ultra-Low Gossypol Cottonseed (ULGCS). Six Angus and Angus-cross calves (two steers and one bull per group) were used in a 28-day feeding trial in a crossover design. Each group was fed either DP1646 or ULGCS for a 7-d acclimation period followed by a 7-d measured intake period. Treatment groups were then switched to the other variety for a second acclimation and measured period. Intake was greater (P = 0.0011) for ULGCS than for DP1646, with an average intake of 2.20 ± 0.24 kg and 1.06 ± 0.24 kg, respectively. Free gossypol intake was not different (P = 0.9371) among treatments with an average daily intake of 13 ± 0.1 ppm and 2 ± 0.8 ppm for DP1646 and ULGCS, respectively. An in situ digestibility trial was conducted using two ruminally-cannulated steers to compare the 72-h digestibility of DP1646 and ULGCS. There were no differences (P = 0.5910) between treatments in total DM digestibility between WCS varieties or treatment by time interaction (P = 0.1270). When evaluating digestibility relative to time, differences were observed (P ≤ 0.0013) at 24, 48, and 72 h. These results indicate that WCS intake was greater for the ULGCS than DP1646, and significant digestibility of either variety was not observed until 24 h of digestion.