Relative RNA Content as a Measure of Condition in Larval and Juvenile Fish

1996 ◽  
Vol 47 (2) ◽  
pp. 301 ◽  
Author(s):  
IM Suthers ◽  
JJ Cleary ◽  
SC Battaglene ◽  
R Evans

The RNA:DNA ratio for first-feeding larvae (12 days after hatching, 4-6 mm standard length, SL) of Australian bass (Percichthyidae, Macquaria novemaculeata) exposed to four different feeding regimes over 8 days was found to be insensitive to the level of starvation. An alternative condition index based on residuals derived from the regression of RNA on SL showed significant differences over the course of the experiment; these reflected the four feeding treatments. Field collections of juvenile monacanthids (Paramonacanthus otisensis, 10-30 mm SL) from a local estuary revealed no significant difference in RNA: DNA ratio at three sites over six weeks. A residual-based index (RNA on dry weight) showed parallel fluctuations at all sites; they were positively correlated with water temperature. The RNA : DNA ratio depends on the difference in fluorescence between total nucleic acids (TNA, using thiazole orange) and DNA (using Hoechst 33258) to calculate RNA, as there is no RNA-specific fluorescent dye. The numerator is thus dependent on the denominator, and measurement error may be compounded in the ratio, exacerbating potential variability in the index. Ratios may also be variably correlated with age or size and consequently may erroneously indicate condition or growth in larger and faster-growing fish.

2021 ◽  
Vol 12 ◽  
Author(s):  
Jianqin Xu ◽  
Xuejie Wang ◽  
Huaqing Zhu ◽  
Futong Yu

All over the world, a common problem in the soil is the low content of available zinc (Zn), which is unevenly distributed and difficult to move. However, information on the foraging strategies of roots in response to heterogeneous Zn supply is still very limited. Few studies have analyzed the adaptability of maize inbred lines with different Zn efficiencies to different low Zn stress time lengths in maize. This study analyzed the effects of different time lengths of low Zn stress on various related traits in different inbred lines. In addition, morphological plasticity of roots and the response of Zn-related important gene iron-regulated transporter-like proteins (ZIPs) were studied via simulating the heterogeneity of Zn nutrition in the soil. In this report, when Zn deficiency stress duration was extended (from 14 to 21 days), under Zn-deficient supply (0.5 μM), Zn efficiency (ZE) based on shoot dry weight of Wu312 displayed no significant difference, and ZE for Ye478 was increased by 92.9%. Under longer-term Zn deficiency, shoot, and root dry weights of Ye478 were 6.5 and 2.1-fold higher than those of Wu312, respectively. Uneven Zn supply strongly inhibited the development of some root traits in the -Zn region. Difference in shoot dry weights between Wu312 and Ye478 was larger in T1 (1.97 times) than in T2 (1.53 times). Under heterogeneous condition of Zn supply, both the –Zn region and the +Zn region upregulated the expressions of ZmZIP3, ZmZIP4, ZmZIP5, ZmZIP7, and ZmZIP8 in the roots of two inbred lines. These results indicate that extended time length of low-Zn stress will enlarge the difference of multiple physiological traits, especially biomass, between Zn-sensitive and Zn-tolerant inbred lines. There were significant genotypic differences of root morphology in response to heterogeneous Zn supply. Compared with split-supply with +Zn/+Zn, the difference of above-ground biomass between Zn-sensitive and Zn-tolerant inbred lines under split-supply with –Zn/+Zn was higher. Under the condition of heterogeneous Zn supply, several ZmZIP genes may play important roles in tolerance to low Zn stress, which can provide a basis for further functional characterization.


1957 ◽  
Vol 35 (3) ◽  
pp. 187-193 ◽  
Author(s):  
M. A. A. Vonk ◽  
L. W. McElroy ◽  
J. P. Bowland ◽  
R. T. Berg

Results of experiments to investigate the effect of dietary chlortetracycline on pancreas dry weight and on the crude fat content and hydrolase activity of the gland are presented. Chlortetracycline fed at a level of 20 g. per ton of feed caused an increase in rate of gain and efficiency of feed utilization by pigs between the ages of 9 and 17 weeks. An effect on the pancreas was indicated by significant increases in: (a) dry weight, (b) total protease and amylase activity, and (c) amylase activity per gram dry matter of the glands from animals receiving the supplemented ration. The difference remained significant after adjustment for body weight by covariance in the case of amylase activity but not for dry weight or protease activity, indicating that the effect of chlortetracycline on amylase activity was more pronounced than that on rate of gain of pigs, pancreas dry weight, or pancreatic protease activity. No significant difference in the crude fat content of the pancreas attributable to the inclusion of chlortetracycline in the ration was observed.


1987 ◽  
Vol 63 (3) ◽  
pp. 1008-1011 ◽  
Author(s):  
S. J. Allen ◽  
R. E. Drake ◽  
J. Katz ◽  
J. C. Gabel ◽  
G. A. Laine

Escherichia coli endotoxin causes increased capillary membrane permeability and increased pulmonary arterial pressure (PAP) in sheep. If the pulmonary hypertension extends to the level of the microvasculature, then the increased microvascular pressure may contribute to the pulmonary edema caused by endotoxin. We tested the hypothesis that reducing the pulmonary hypertension would reduce the amount of edema caused by endotoxin. Twelve sheep were chronically instrumented with catheters to measure PAP, left atrial pressure, and central venous pressure. The sheep were divided into two groups. One group (E) of six sheep received an intravenous infusion of 4 micrograms/kg of E. coli endotoxin. The second group (E + SNP) received the same dose of endotoxin as well as a continuous infusion of sodium nitroprusside (SNP) to reduce PAP. Three hours after the endotoxin infusions, the sheep were terminated and the extravascular fluid-to-blood-free dry weight ratios of the lungs were determined (EVF). The base-line PAP was 17.5 +/- 2.7 mmHg. A two-way analysis of variance demonstrated a significant difference (P less than 0.01) in PAP between the E and E + SNP groups. Although PAP in each group varied as a function of time, the difference between the two groups did not. The mean PAP for the E + SNP group (20.9 +/- 1.5 mmHg) was lower than the E group PAP of 27.3 +/- 2.1 mmHg after the endotoxin spike. Furthermore, the E + SNP group EVF (3.9 +/- 0.2) was significantly less than the EVF of the E group (4.7 +/- 0.5).(ABSTRACT TRUNCATED AT 250 WORDS)


1987 ◽  
Vol 67 (2) ◽  
pp. 457-466 ◽  
Author(s):  
S. L. A. HOBBS

In spaced field plantings, triazine-resistant types of Brassica campestris L. and B. napus L. had a carbon dioxide exchange rate (CER) 28% lower in 1983 and 25% lower in 1984 than normal (triazine-susceptible) types. In plots simulating agronomic spacings in 1984, the difference between CER in normal and resistant types was 17% for B. campestris, 14% for B. napus and 13% for B. juncea L. Differences were apparent throughout the season and were not associated with any particular stage of growth. Resistant progeny from reciprocal crosses between resistant and susceptible plants of B. napus exhibited reduced CER at all levels of photosynthetically active radiation and at all temperatures. There was no significant difference between plant types for chlorophyll a + b content or chlorophyll a/b ratio. Shoot dry weight, stomatal resistance and specific leaf weight were higher in the normal types, but there was no difference between types in either relative growth rate or net assimilation rate. The reduced biomass was not therefore linked to reduced CER.Key words: Carbon dioxide exchange rate, herbicide, oilseed, rapeseed


2020 ◽  
Vol 38 (3) ◽  
pp. 246-253
Author(s):  
Jing Yang ◽  
Biao Zhu ◽  
Xiaolei Ni ◽  
Yong He

ABSTRACT Nitrogen (N) strongly affects plant growth. However, little is known about the effects of the ammonium/nitrate ratio on pakchoi (Brassica rapa), especially its glucosinolates (GSs) contents which are involved in plant defense and many of them benefit to human health. The aim of this study was to evaluate the effects of a constant N supply (8 mM) but with five ammonium/nitrate ratios (namely 0/8 mM, 2/6 mM, 4/4 mM, 6/2 mM and 8/0 mM) on the growth of pakchoi in a hydroponic system in 2 years. In both years, a higher biomass (dry weight) was in the 4/4 and 2/6 ammonium/nitrate treatments (2.3 and 2.2-fold compared to 8/0, respectively), with no significant difference in biomass between these two treatments. The biomass then decreased with increasing proportions of ammonium in the N supply from more than 10 g/pot to below 5 g/pot. The N and sulfur contents were strongly affected in the sole nitrate or ammonium treatments, as were the contents of chlorophyll, lutein, and β-carotene. Most of the individual glucosinolates (GSs) detected in pakchoi showed the highest concentrations in the sole ammonium treatment. The ammonium/nitrate ratio also affected the types of GSs. The highest proportion of indolyl GSs and the lowest proportion of aromatic GSs were in the sole ammonium treatment. We concluded that a high ammonium level decreases the biomass but increases the GSs concentrations in pakchoi. Further studies are required to explore the difference in GSs metabolism among plants supplied with different ammonium/nitrate ratios.


HortScience ◽  
1999 ◽  
Vol 34 (3) ◽  
pp. 549C-549
Author(s):  
Gaston Esparza ◽  
Ted M. DeJong ◽  
Steve A. Weinbaum

The effect of water stress during the harvest period on carbohydrate reserves at the end of the growing season was studied for mature, field-grown almond trees. The following irrigation treatments were imposed during 1995, 1996, and 1997: a) full irrigation (FI) (irrigation every 3–7 days), b) moderate stress (MS) (18 days of irrigation cut-off), and c) severe stress (SS) (35, 47, and 53 days of irrigation cut-off for 1995, 1996, and 1997, respectively). Midday stem (Yms) and predawn leaf (Ypd) water potentials were monitored during each season's stress. Three trees of contrasting treatments (FI vs. SS) were excavated on 10 Dec. 1997 and divided into tree components for dry weight and TNC concentration determination. Although there was no significant difference in whole-tree biomass between the excavated FI and SS trees, total new stem growth of SS trees was half of FI trees. TNC concentrations in the organs of SS trees were significantly reduced compared to FI trees. Total calculated whole tree TNC content for SS trees was 26.1% less than FI trees. The difference in TNC content between FI and SS trees was larger for roots (34.9%) than for the aerial parts (21.1%) indicating the higher sensitivity of roots for reflecting reserve status. Although roots constituted just 13.4% of the whole tree biomass, they stored 36.4% of TNC. Only roots exhibited a clear association between the minimum values of Yms and Ypd during the season and TNC concentration of 12 non-excavated additional trees that were subsampled at the end of the growing season.


1957 ◽  
Vol 35 (1) ◽  
pp. 187-193 ◽  
Author(s):  
M. A. A. Vonk ◽  
L. W. McElroy ◽  
J. P. Bowland ◽  
R. T. Berg

Results of experiments to investigate the effect of dietary chlortetracycline on pancreas dry weight and on the crude fat content and hydrolase activity of the gland are presented. Chlortetracycline fed at a level of 20 g. per ton of feed caused an increase in rate of gain and efficiency of feed utilization by pigs between the ages of 9 and 17 weeks. An effect on the pancreas was indicated by significant increases in: (a) dry weight, (b) total protease and amylase activity, and (c) amylase activity per gram dry matter of the glands from animals receiving the supplemented ration. The difference remained significant after adjustment for body weight by covariance in the case of amylase activity but not for dry weight or protease activity, indicating that the effect of chlortetracycline on amylase activity was more pronounced than that on rate of gain of pigs, pancreas dry weight, or pancreatic protease activity. No significant difference in the crude fat content of the pancreas attributable to the inclusion of chlortetracycline in the ration was observed.


Author(s):  
A. Mohd Zulkhairi ◽  
M. Razali ◽  
M. B. Umikalsum ◽  
G. Mohd Norfaizal ◽  
A. Aimi Athirah ◽  
...  

Aims: To determine the oxalate contents in different varieties of taro (Colocasia esculenta) collected in Peninsular Malaysia. Study Design: Ultra High-Performance Liquid Chromatography (UHPLC) with UV detector (Diode Array Detection, (DAD)) was used to determine the total and soluble oxalate contents in different varieties of taro corms. Meanwhile, the insoluble oxalate content (calcium oxalate) was estimated from the subtraction of soluble oxalate content from total oxalate content. Place and Duration of Study: Malaysian Agriculture Research and Development Institute (MARDI Headquarters), Persiaran MARDI-UPM, 43400 Serdang, Selangor, Malaysia between December 2018 to December 2019. Methodology: 9 different varieties of taro were collected from different locations in Peninsular Malaysia. All the samples were analysed for their oxalate contents. Extractions were carried out to determine the total oxalate and soluble oxalate contents. All the samples were analysed using UHPLC. The generated data of oxalate contents were analysed using Analysis of Variance (ANOVA). Results: There is a significant difference (P <.05) between the oxalate content in the examined varieties with respect to the amount of total, soluble and insoluble oxalate contents. The putih variety has significantly the highest amount of total oxalate content with 218.8 ± 28.2 mg/100 g DW (dry weight) followed by the udang variety with 184.2 ± 24.7 mg/100 g DW and the wangi variety with 178.3 ± 5.1 mg/100 g DW. Tapak badak variety has the lowest total oxalate content with 70.5 ± 20.1 mg/100 g DW. Result showed that wangi variety has significantly the highest soluble oxalate content with 135.1 ± 4.8 mg/100 g DW followed by udang with 100.9 ± 49.8 mg/100 g DW. The lowest soluble oxalate content was found in tapak badak with 17.7 ± 2.9 mg/100 g DW. Conclusion: Despite many factors contributing to the difference in oxalate content between varieties, this study would help researchers or policy makers to suggest potential taros for commercial cultivation.


Weed Science ◽  
1984 ◽  
Vol 32 (5) ◽  
pp. 686-690 ◽  
Author(s):  
Ian N. Morrison ◽  
Denise C. Maurice

ED50values (the dosage required to reduce the posttreatment gain in dry weight by 50%) for diclofop applied to green and yellow foxtail [Setaria viridis(L.) Beauv. ♯3SETVI andS. lutescens(Weigel.) Hubb. ♯ SETLU] at the two- and four-leaf stages were calculated from linear regression equations derived by plotting the logarithm of the applied dosage against the relative growth reduction expressed as a probit value. At the two-leaf stage, green foxtail was more susceptible to the chemical than yellow foxtail but at the four-leaf stage there was no significant difference in response of the two species. At least part of the difference in sensitivity of the two species at the two-leaf stage could be accounted for by differences in spray retention, with green foxtail retaining 1.8 times (expressed as μL/cm2) or 3.5 times (expressed as μL/g dry weight) as much spray as yellow foxtail, despite the fact that yellow foxtail had a greater projected leaf area. At the four-leaf stage, the amount of spray retained by both species calculated on a per gram dry-weight basis was significantly less than at the two-leaf stage, accounting in part for the higher ED50values obtained at the later growth stage. However, there appeared to be no direct relationship between the amount of spray retained and the comparative growth response of the two weeds at the later stage of application.


2021 ◽  
Vol 15 ◽  
pp. 1-5
Author(s):  
Jiunn Luh Tan ◽  
Kok Yu Ang ◽  
Min Hui Chow ◽  
Eunice Ting Yee Lee ◽  
Kuan Hoong Lee ◽  
...  

Chicken manure is one of the popular organic fertilizers used in vegetable farming in Malaysia. Chicken manure is divided into two types, namely broiler chicken manure (BCM) and layer chicken manure (LCM). The effectiveness of these chicken manures is often questionable due to the different method of raising broilers and layers. Therefore, the present study was carried out to determine the effect of the broiler and layer chicken manures on the growth of choy sum (Brassica chinensis L. var. parachinensis), a common farmed leafy vegetable in the country. This study was carried out in the Agricultural Park of Universiti Tunku Abdul Rahman (Perak Campus), Malaysia from February to May 2019. Randomized Complete Block Design (RCBD) methods were used in this study. The chicken manures were composted for roughly 2 months before the experiment. There was no significant difference in the dry weight, plant height and root length of the choy sum treated with either BCM or LCM. Although the choy sum treated with BCM has a higher fresh weight (177.53 g) as compared to that of LCM (134.64 g), this may be due to the natural fluctuation of water content within the plants. Therefore, the results of the present study show that both the chicken manure has a similar effect on the growth of choy sum. The authors recommend further studies on the chemical composition and optimization of chicken manure application in enhancing the growth and yields of leafy vegetables.


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