Identification and quantification of indole-3-acetic acid in the kelp Laminaria japonica Areschoug and its effect on growth of marine microalgae

A method was established for the identification and quantification of indole-3-acetic acid (IAA) in extracts of the kelp Laminaria japonica. An IAA content of 90–95 μg kg⁻¹ fresh weight in kelp extract was determined by high performance liquid chromatography (HPLC). IAA identification was based on a combination of co-chromatography and comparative chromatography with a standard, analysis of UV spectra, and atmospheric pressure electrospray mass spectrometry (APESI-MS). IAA was isolated by silica gel chromatography and HPLC. The effect on the growth of four marine microalgae of the pure IAA isolated from kelp extract was investigated. Exogenously added IAA from kelp enhanced the growth of Chlorella sp., Dunaliella salina and Porphyridium cruentum, but not that of Chaetoceros muelleri. IAA from kelp significantly inhibited the accumulation of soluble cellular proteins in Chlorella sp. and P. cruentum, and had a very significant effect on chlorophyll biosynthesis in Chlorella sp. However, there was no obvious effect of IAA on the regulation of biosynthesis of cellular polysaccharides in these four marine microalgae.     

Ecological studies on the population of isaza,Chaenogobius Isaza Tanaka,in Lake Biwa,with special reference to the effects of population density upon its growth

1. In order to get the knowledge on the age composition of “isaza” population in Lake Biwa and the effect of population density on growth, monthly distribution of mean body length and mean body weight has been analyzed on the basis of monthly haul by “isazabiki” trawl during 1949 to 1953 and also 1960 to 1965.
2. There is no apparent sex difference in the growth in the first and second years of life.
3. “Isaza” population is composed of two age groups, age 0 and 1 groups (1+fish), the latter occupying by far the greater part in commercial catch.
4. During the growth season fishes of both ages feed mainly on zooplankton, though in winter frequently take chironomid larvae, gammaridae and others in volume.
5. The growth season falls in the period from April to October in both age groups.
6. A considerable yearly variation occurring in growth is in close connection with the fluctuation of population density of all ages.
7. The influence affected by the density of age 1 group is larger than that by age 0 group.

     

Insights into the structure–function relationship of brown plant hopper resistance protein,Bph14 of rice plant: a computational structural biology approach

Brown plant hopper (BPH) is one of the major destructive insect pests of rice, causing severe yield loss. Thirty-two BPH resistance genes have been identified in cultivated and wild species of rice Although, molecular mechanism of rice plant resistance against BPH studied through map-based cloning, due to non-existence of NMR/crystal structures of Bph14 protein, recognition of leucine-rich repeat (LRR) domain and its interaction with different ligands are poorly understood. Thus, in the present study, in silico approach was adopted to predict three-dimensional structure of LRR domain of Bph14 using comparative modelling approach followed by interaction study with jasmonic and salicylic acids. LRR domain along with LRR-jasmonic and salicylic acid complexes were subjected to dynamic simulation using GROMACS, individually, for energy minimisation and refinement of the structure. Final binding energy of jasmonic and salicylic acid with LRR domain was calculated using MM/PBSA. Free-energy landscape analysis revealed that overall stability of LRR domain of Bph14 is not much affected after forming complex with jasmonic and salicylic acid. MM/PBSA analysis revealed that binding affinities of LRR domain towards salicylic acid is higher as compared to jasmonic acid. Interaction study of LRR domain with salicylic acid and jasmonic acid reveals that THR987 of LRR form hydrogen bond with both complexes. Thus, THR987 plays active role in the Bph14 and phytochemical interaction for inducing resistance in rice plant against BPH. In future, Bph14 gene and phytochemicals could be used in BPH management and development of novel resistant varieties for increasing rice yield.     

Identification and Validation of Molecular Markers Associated with Pachymetra Root Rot and Brown Rust Resistance in Sugarcane Using Map- and Association-based Approaches

Marker-assisted selection for traits that are difficult to screen for, such as resistance to many sugarcane diseases, has the potential to facilitate the development of improved cultivars in sugarcane. Pachymetra root rot (PRR) and brown rust resistance ratings were obtained over two years for 192 I1 progeny (progeny produced by two heterozygous, non-inbred parental lines) of a sugarcane (Saccharum spp. hybrid) cross between two elite sugarcane clones, Q117 and 74C42. Approximately 1000 single-dose markers, including microsatellite (SSR), amplified fragment length polymorphism (AFLP) and restriction fragment length polymorphism (RFLP) markers, were scored across the population and maps containing approximately 400 markers were constructed for each parent. At p ≤ 0.01, two genomic regions, one from the female Q117 map and a different region from the 74C42 male map, plus an unlinked bi-parental simplex marker (single-dose marker present in both parents) were identified as associated with PRR over both years of data collection. These regions explained between 6 and 16% of the phenotypic variation. An additional region was identified in the female map as associated with PRR at p ≤ 0.01 in one year and p ≤ 0.05 in the second year. This region explained between 4 and 8% of the phenotypic variation. For brown rust, two genomic regions, one from the female map and one from the male map, plus an unlinked marker from both maps, were identified as associated with brown rust resistance at p ≤ 0.01 over two years of phenotypic data. Each region explained between 7 and 18% of the phenotypic variation. Several additional regions were identified in both maps as associated with brown rust at p ≤ 0.01 in one year and p ≤ 0.05 in the second year. These regions also explained between 5 and 11% of the phenotypic variation. To validate these markers and determine whether they would be useful in alternative germplasm, markers from each genomic region associated with PRR or brown rust were screened across a set of 154 elite sugarcane clones; PRR and brown rust ratings were available for 131 and 72 of the clones, respectively. For PRR, three of the 6 markers tested remained significantly associated (p ≤ 0.01) with resistance ratings in the elite clone set. For brown rust, only one of the seven markers tested remained significantly associated (p ≤ 0.01) with resistance in the elite clone set, with one other marker associated at p ≤ 0.05. These results suggest that these markers could be broadly effective in selecting for PRR and/or brown rust resistance in sugarcane breeding programs.     

Selection responses for the number of fertile eggs of the Brown Tsaiya duck (Anas platyrhynchos) after a single artificial insemination with pooled Muscovy (Cairina moschata) semen

A seven-generation selection experiment comprising a selected (S) and a control (C) line was conducted with the objective of increasing the number of fertile eggs (F) of the Brown Tsaiya duck after a single artificial insemination (AI) with pooled Muscovy semen. Both lines consisted of about 20 males and 60 females since parents in each generation and each female duck was tested 3 times, at 26, 29 and 32 weeks of age. The fertile eggs were measured by candling at day 7 of incubation. The selection criterion in the S line was the BLUP animal model value for F. On average, 24.7% of the females and 15% of the males were selected. The direct responses to the selection for F, and correlated responses for the number of eggs set (Ie), the number of total dead embryos (M), the maximum duration of fertility (Dm) and the number of hatched mule ducklings (H) were measured by studying the differences across the generations of selection between the phenotypic value averages in the S and C lines. The predicted genetic responses were calculated by studying the differences between the S and C lines in averaged values of five traits of the BLUP animal model. The selection responses and the predicted responses showed similar trends. There was no genetic change for Ie. After seven generations of selection, the average selection responses per generation were 0.40, 0.33, 0.42, 0.41 genetic standard deviation units for F, M, Dm, and H respectively. Embryo viability was not impaired by this selection. For days 2–8 after AI, the fertility rates (F/Ie) were 89.2% and 63.8%, the hatchability rates (H/F) were 72.5% and 70.6%, and (H/Ie) were 64.7% and 45.1% in the S and C lines respectively. It was concluded that upward selection on the number of fertile eggs after a single AI with pooled Muscovy semen may be effective in ducks to increase the duration of the fertile period and the fertility and hatchability rates with AI once a week instead of twice a week.     

摄食对印度蜓蜥代谢率的影响

通过测定摄食后印度蜓蜥雌性成体的耗氧量变化 ,研究摄食特殊热动力作用 (SDA)。动物分为摄食黄粉虫幼虫实验组和禁食对照组 ,两组蜥蜴平均体重无显著差异。测定耗氧量前 ,将所有动物在 3 0℃恒温室内禁食 3d。用容积为 3 0 0ml的封闭式呼吸室测定两组蜥蜴在 3 0℃条件下连续 3d的耗氧量 ,测定间隔时间为 4～ 2 5h。禁食组动物实验期间的耗氧量无显著的时间变异 ,实验组动物耗氧量的时间变异显著 ,这些结果表明摄食影响印度蜓蜥的代谢率。实验组动物摄食 8h后耗氧量已显著大于禁食组 ,摄食 3 0h后两组动物的耗氧量无显著差异。印度蜓蜥达到SDA峰值的平均时间约为 1 2 7h ,SDA峰值耗氧量是禁食对照组动物耗氧量的 1 6倍。印度蜓蜥单次摄食实验中的SDA具有进食后耗氧量迅速增加 ,达到峰值后下降至摄食前水平的典型模式。     

Tolerance of brown bear spermatozoa to conditions of pre-freezing cooling rate and equilibration time

Specific protocols for the cryopreservation of endangered Cantabrian brown bear spermatozoa are critical to create a genetic resource bank. The aim of this study was to assess the effect of cooling rates and equilibration time before freezing on post-thawed brown bear spermatozoa quality. Electroejaculates from 11 mature bears were extended to 100 × 10⁶ spermatozoa/mL in a TES–Tris–Fructose–based extender, cryopreserved following performance of the respective cooling/equilibration protocol each sample was assigned to, and stored at −196 °C for further assessment. Before freezing, after thawing, and after 1 hour's incubation post-thawing at 37 °C (thermal stress test), the quality of the samples was assessed for motility by computer-assisted semen analysis, and for viability (SYBR-14/propidium iodide), acrosomal status (peanut agglutinin–fluorescein isothiocyanate /propidium iodide), and sperm chromatin stability (SCSA) by flow cytometry. In experiment 1, three cooling rates (0.25 °C/min, 1 °C/min, and 4 °C/min) to 5 °C were assessed. After thawing, total motility (%TM) was higher and percentage of damaged acrosomes (%dACR) was lower (P < 0.05) for 0.25 °C/min than for 4 °C/min. The thermal stress test data indicated equally poor quality (P < 0.05) for the 4 °C/min cooled samples in viability (%VIAB), %dACR, %TM, and progressive motility (%PM). In experiment 2, the effect of a pre-freezing equilibration period at 5 °C for 1 hour (cooling at 0.25 °C/min) was evaluated. Samples kept at 5 °C for 1 hour showed higher (P < 0.05) values than the nonequilibrated ones for both thawing (%dACR) and thermal stress test (%VIAB, %TM, and %PM). In experiment 3, samples stored without cooling and equilibration (direct freezing) were compared with the samples cooled at 0.25 °C/min and equilibrated for 1 hour (control freezing). Using thermal stress test, we observed that direct freezing causes damage in viability, acrosomal status, and motility of spermatozoa compared with the control group (P < 0.05). In conclusion, our results suggest that slow cooling rates to 5 °C and at least 1 hour equilibration time are necessary for the effective cryopreservation of brown bear sperm.     

Unimodal response of fish yield to dissolved organic carbon

Here, we demonstrate a contrasting effect of terrestrial coloured dissolved organic material on the secondary production of boreal nutrient poor lakes. Using fish yield from standardised brown trout gill‐net catches as a proxy, we show a unimodal response of lake secondary productivity to dissolved organic carbon (DOC). This suggests a trade‐off between positive and negative effects, where the initial increase may hinge upon several factors such as energy subsidising, screening of UV‐radiation or P and N load being associated with organic carbon. The subsequent decline in production with further increase in DOC is likely associated with light limitations of primary production. We also show that shallow lakes switch from positive to negative effects at higher carbon loads than deeper lakes. These results underpin the major role of organic carbon for structuring productivity of boreal lake ecosystems.     

Tejido adiposo: heterogeneidad celular y diversidad funcional

There are two types of adipose tissue in the body whose function appears to be clearly differentiated. White adipose tissue stores energy reserves as fat, whereas the metabolic function of brown adipose tissue is lipid oxidation to produce heat. A good balance between them is important to maintain energy homeostasis. The concept of white adipose tissue has radically changed in the past decades, and is now considered as an endocrine organ that secretes many factors with autocrine, paracrine, and endocrine functions. In addition, we can no longer consider white adipose tissue as a single tissue, because it shows different metabolic profiles in its different locations, with also different implications. Although the characteristic cell of adipose tissue is the adipocyte, this is not the only cell type present in adipose tissue, neither the most abundant. Other cell types in adipose tissue described include stem cells, preadipocytes, macrophages, neutrophils, lymphocytes, and endothelial cells. The balance between these different cell types and their expression profile is closely related to maintenance of energy homeostasis. Increases in adipocyte size, number and type of lymphocytes, and infiltrated macrophages are closely related to the metabolic syndrome diseases. The study of regulation of proliferation and differentiation of preadipocytes and stem cells, and understanding of the interrelationship between the different cell types will provide new targets for action against these diseases.