Photoperiod Conditions Research Articles

Effect of environmental conditions on the changes of voltinism in three lines of Bombyx mori.

This work aims to estimate the voltinism differences in the studied lines and the influence of biological and environmental variables on this trait. Three Bombyx mori. lines were used. One polyvoltine (Indian, C. Nichi) and two bivoltine (Chinese6-C6 and Japanese7-J7). Silkworms were reared under controlled conditions of temperature (24±1, 26±1, 28±1°C) and photoperiod (8-16, 12-12, 16-8 light/darkness) during the life cycle. The measured biological characters were duration of larval period (DLP), larval weight on fifth day of V instar (LW(V-5)), rate of weight (RWV), duration of life cycle (DLC), fecunditiy (NE), fertility (F) and voltinism (V). Voltinism was estimated using a linear regression model; the variables that influence voltinism were found using a multiple regression analysis; and the effect of environmental conditions on change of voltinism employing an ANOVA. The results show that the variables that affect voltinism are different for each line, which demonstrates the effect of the line factor. Nichi voltinism was affected by the six measured variables, while in C6 and J7 where voltinisms depends on the duration of diapause, some variables were excluded from the model. In Indian tropical polyvoltine, the temperature was the influencing factor, while in Chinese and Japanese bivoltines lines was the photoperiod.

The Environmental Consequence of Automobile and Motor-bike Traffic Noise Intensity on the Activity of African Grey Parrots (Psithacus erittacus) in Limbe Botanic Garden, Southwest Region, Cameroon

Highway traffic noise pollution is unavoidably generated by human activity, and has caused serious health problems to the human society. However, it’s also a challenge to many wildlife species, though, continous exposure to the noise stimuli has seemingly given them adaptation. Understanding the ability of wildlife species to cope with noise pollution is complex, thus, requires research. Therefore, the objective of this study was to explore automobile and motor bike traffic noise intensity on African grey parrots’ activity in Limbe Botanic Garden. The research data was collected for a period of three months from 8:00 am - 5:00 pm each day. Traffic noise pollution is difficult to avoid in urban settings because of huge human population and its activity, however, its interference with other sounds is common, and wildlife population living in cities, such as birds are affected. The study revealed a positive significance X2 = 25.796 df=2 P=0.000 and X2 =39.489 df=6 P=0.000 on photoperiod and meteorological conditions respectively. Moreover, meteorological changes in the study area recorded significance on sun 75%, cloud 15%, wind 6%, and rain 4% respectively. Furthermore, noise intensity of automobile and motor bike traffic around the botanic garden area showed a significance X2 = 5.657 df=8 P<0.05, and r = 0.209 P=0.000 on behavior and parrots' food availability respectively. The highest parrots’ activity recorded during this study was on contact calls 54%, and the least was roosting 3%. Though a comprehensive inventory is not carried out on the parrot population in Cameroon, there are signs, these birds are already facing population reduction; principally because of the pet-trade driven by the craving human love for the colourful plumage morphology and the talented sound-mimicking behavior of the parrots. There is a necessity for further study to be carried out on the birds’ population census in the country. The study found that traffic noise intensity at all levels have a negative influence on the aggregation activity of grey parrots, reason why they avoid the vegetation along the streets of the garden. Finally, oil palm fruit-feeding was a dominant activity recorded in this study, hence, we recommend more oil palm trees be planted in the garden far from major roads to enrich the feeding environment of the grey parrots.

Evaluation of membrane fouling in a microalgal-bacterial membrane photobioreactor treating secondary wastewater effluent: effect of photoperiod conditions

In microalgal-bacterial membrane photobioreactors, membrane fouling was mainly determined by the biopolymer cluster content, with best performance being attained at intermediate photoperiods.

Effects of constant light and dark conditions on the locomotor activity, body mass, and body temperature rhythms of Eurasian Tree Sparrows (Passer montanus)

Light is an essential environmental cue influencing the endogenous circadian clocks that regulate behavioral and physiological processes in animals. Despite extensive research on the circadian rhythms of avian behavior and physiology, the mechanisms by which they adapt and adjust to abnormal photoperiod conditions, such as artificial light, have yet to be fully elucidated. Here, the circadian rhythms of the body mass, activity, and core and peripheral body temperatures of the Eurasian Tree Sparrow (Passer montanus, ETS)—a diurnal passerine—were examined under three different lighting conditions: constant light (LL), constant darkness (DD), and normal light–dark cycles (LD). Our results showed that the activity, body mass, core, tarsometatarsus, and eye temperatures of the ETSs varied significantly with treatment, time, and the interaction between treatment and time; however, there was no significant change in body mass in response to the interaction between time and treatment. Under LD conditions, the ETSs exhibited significant circadian rhythms in activity and core, tarsometatarsus, and eye temperatures. Under LL conditions, only the core temperature exhibited significant rhythmicity. Under DD conditions, there were no significant circadian rhythms in activity, body mass, and eye temperature; however, the core and tarsometatarsus temperatures remained rhythmic. Our results indicate that the core body temperature rhythm of ETS is endogenous and can be maintained under abnormal photoperiods. In contrast, the activity and body surface temperature, uncoupled from the core body temperature under abnormal photoperiod conditions, strongly depend on light. These results differ from those of other diurnal avian species, suggesting a unique coping mechanism of ETS in response to an abnormal photoperiod.

North vs. South: Contrasting patterns in the phenotypic plasticity of the firebug Pyrrhocoris apterus (Hemiptera: Pyrrhocoridae) at the latitudinal extremes of its distribution range

In widely distributed insects, some life-history traits are conserved across the whole distribution range and are considered species-specific while other such traits differ geographically. This interplay of geographic variation and phenotypic conservatism is poorly understood even in relatively well-studied model species. Furthermore, a careful study may reveal that conventionally stable traits, such as the lower temperature threshold for development and the sum of degree-days, are both geographically variable and environmentally plastic. We studied how photoperiodic conditions and temperature jointly affect immature development, adult body size and wing polymorphism in two populations of the firebug from the opposite latitudinal margins of this species' range. All the three traits rarely clearly differ under short-day and long-day conditions or between north and south. Instead, we find prevalent temperature-by-photoperiod and temperature-by-origin interactions, which emphasize that it is not only the absolute values of these traits but the degree of their temperature-dependence, or thermal plasticity, that varies in time (in response to seasonal changes in day length) and in space (along latitudinal gradients). These results indicate that caution should be exercised when extrapolating any life-history traits in P. apterus beyond the season when and the location where these were measured. In particular, the use of a constant lower temperature threshold coupled with a constant sum of degree-days is likely to oversimplify the diversity of current and projected phenological patterns in this species.

Neuropeptide F regulates feeding via the juvenile hormone pathway in Ostrinia furnacalis larvae.

Feeding by pests is one of the most important reasons for reductions in agricultural crop yield. This study aimed to reveal how juvenile hormone (JH) participates in larval feeding regulation of the Asian corn borer Ostrinia furnacalis. Larvae of O.furnacalis exhibit a daily circadian feeding rhythm, with a peak at ZT18 and a trough at ZT6 under both photoperiod (LD) and constant dark (DD) conditions, which may be eliminated by application of fenoxycarb, a JH active analogue. JH negatively regulates larval feeding as a downstream factor of neuropeptide F (NPF), in which knocking down JH increases larval feeding amount along with body weight and length. The production of JH in the brain-corpora cardiaca-corpora allata (brain-CC-CA) is regulated by brain NPF rather than gut NPF, which was demonstrated in Drosophila larvae through GAL4/UAS genetic analysis. In addition, feeding regulation of JH is closely related to energy homeostasis in the fat body by inhibiting energy storage and promoting degradation. The JH analogue fenoxycarb is an effective pesticide against O.furnacalis, controlling feeding and metabolism. The brain NPF system regulates JH, with functions in food consumption, feeding rhythms, energy homeostasis and body size. This study provides an important basis for understanding the feeding mechanism and potential pest control of O.furnacalis. © 2022 Society of Chemical Industry.

Reproductive management of the mugilid Liza aurata and characterization of proximate and fatty acid composition of broodstock tissues and spawnings

The golden grey mullet (Liza aurata) is a promising species for aquaculture's sustainable expansion. However, the lack of sustainable juvenile provision, mainly related to the lack of reproductive control, is one of the most significant bottlenecks for further expanding the culture of this species. In many cases, mullet broodstock management needs the application of hormone treatments to induce gonadal maturation or spawning. However, no works are directly related to the broodstock collection, acclimation, and reproductive management of Liza aurata. On the other hand, the knowledge of essential fatty acids (EFA) requirements and mobilization patterns by the broodstock is a first step to designing appropriate feeding protocols and formulas, which are crucial for the success of reproduction and larval development.For these reasons, this study aimed 1) to describe for the first time the reproductive management of Liza aurata broodstock under controlled conditions and 2) to offer a first approach to the reproductive lipid metabolism of the former species.A selection of 22 Liza aurata broodstock from wild origin was acclimated in open seawater conditions. Additionally, the proximate and fatty acid composition of body tissues (gonads, liver, and muscle) of the initial wild population were evaluated, to be later compared with the profile of the eggs obtained after one year from the selected broodstock, for the first time described under cultured conditions.The results highlighted the feasibility for the obtention of natural spawnings from broodstock with a mean weight of 787 g and 604 g (females and males, respectively), at a sex ratio of 2:1 (females/males), under natural photoperiod and marine water conditions with temperatures decreasing from 20.4 ± 0.3 °C to 18.8 ± 0.4 °C.On the other hand, it was evidenced the crucial role of HUFA (highly unsaturated fatty acids) precursors for the gonadal development of Liza aurata, primarily for females. Additionally, the wild males' gonads presented a remarkable high content of HUFA, predominantly DHA (docosahexaenoic acid) (34% of the total fatty acids). In the eggs, significant variations appeared under captivity conditions, with lower levels of ARA (arachidonic acid) and EPA (eicosapentaenoic acid) and higher EPA/ARA and DHA/ARA ratios than the wild female gonad. Additionally, it was evidenced the significant role of the liver as a physiological reservoir of HUFA, which seem to be mobilized to the gonad during the maturation process.Present results may help obtain a better insight to adjust broodstock management conditions and feeds, contributing to a more sustainable aquaculture growth.

Effects of different photoperiod conditions on survival, growth, and gonadal development of Takifugu rubripes adults

Photoperiod has a significant influence on fish. In this study, 2.5-year-old Takifugu rubripes (tiger puffer) adults were selected to evaluate the photoperiod impacts (8 h light (L):16 h dark (D), 12L:12D, 16L:8D) from September to January at 15–17 °C on their growth, gonadal development, and survival for a 100-day. The mortality rate of males and females tiger puffer differed among the different photoperiods, and the 8L:16D photoperiod was not suitable for survival of males. At the end of the experiment, the body length, weight gain rate, specific growth rate and condition factor of both males and females tiger puffer were similar among the three photoperiods (P > 0.05). Higher percentage of females had developed to later developing phase and males had developed to spawning capable phase in the 12L:12D treatment, respectively. In particular, 100% of males had testis at the spawning capable phase. The gonadosomatic index values of males and females in the 12L:12D group were significantly higher than those in the 16L:8D group (P < 0.05), but no significant differences between the 8L:16D and 12L:12D groups (P > 0.05). The serum testosterone (T) content of males and the serum estradiol-17β (E2) content of females were highest in the 12L:12D group. The expression of aralkylamine N-acetyltransferase 1a (aanat1a) in the diencephalon/midbrain (D/M) was elevated under 12L:12D treatment in both sex (P < 0.05). The expression level of iodothyronine deiodinase type 2 (dio2) in the saccus vasculosus in males was elevated under the 12L:12D photoperiod (P < 0.05). The levels of gonadotropin-releasing hormone 1 (gnrh1) and gnrh3 mRNA in the D/M of females at later developing stages in the 12L:12D treatment were significantly higher than those in of other treatment groups, and the level of gnrh3 in males under this photoperiod was significantly elevated (P < 0.05). The levels of gonadotropin-inhibiting hormone (gnih) mRNA under 12L:12D were significantly elevated in both males and females (P < 0.05). Under this photoperiod, the levels of follicle stimulating hormone b-subunit (fshb) and luteinizing hormone b-subunit (lhb) in the pituitary gland of females at later developing stages were significantly higher than those of the other two groups (P < 0.05). The expression levels of lhb in males in the 12L:12D and 8L:16D photoperiods were significantly higher than that at 16L:8D (P < 0.05). These results indicated that culture under the 12L:12D photoperiod from September prior to the spawning season could result in accelerated gonadal development of both male and female tiger puffer.

High relative humidity improves leaf burn resistance in flowering Chinese cabbage seedlings cultured in a closed plant factory.

Plant factories that ensure the annual production of vegetable crops have sparked much attention. In the present study, thirty types of common vegetable crops from 25 species and eight families, were grown in a multi-layer hydroponic system in a closed-type plant factory to evaluate the adaptive performance. A total of 20 vegetable crops, belonging to 14 species and 4 families, unexpectedly exhibited different degrees of leaf margin necrosis in lower leaves firstly, then the upper leaves gradually. We defined this new physiological disorder as "leaf burn". It occurred more commonly and severely in cruciferous leafy vegetables. Two different light intensities (150 and 105 µmolm-2s-1 photosynthetic photon flux density (PPFD)), three photoperiod conditions (12, 10 and 8 hd-1) and two canopy relative air humidity (RH) (70% and 90% RH) were set to evaluate the suppression effects on leaf burn occurrence in two commercial flowering Chinese cabbage cultivars ('Sijiu' and 'Chixin'), the special cruciferous vegetable in South China. We discovered that changing light conditions did not fully suppress leaf burn occurrence in the cultivar 'Sijiu', though lower light intensity and shorter photoperiod partly did. Interestingly, the occurrence of leaf burn was completely restrained by an increased canopy RH from 70% to 90%. Specifically, the low RH-treated seedlings occurred varying degree of leaf burn symptoms, along with rapidly decreased water potential in leaves, while the high RH treatment significantly lessened the drop in leaf water potential, together with increased photosynthetic pigment contents, net photosynthetic rate, stomatal conductance and transpiration rate, decreased leaf stomatal aperture and density, and thus reduced the incidence of leaf burn in 'Sijiu' and 'Chixin', from 28.89% and 18.52% to zero, respectively. Taken together, high canopy RH may favor maintaining leaf water potential and improving photosynthesis performance, jointly regulating leaf burn incidence and plant growth.

Physiological and Molecular Responses of Barley Genotypes to Salinity Stress

Among cereals, barley is tolerant to high levels of salinity stress; however, its performance and global production are still dramatically affected by salinity. In this study, we evaluated the behavior of a set of advanced genotypes of barley with aim of assessing the physiological and molecular mechanisms involved in salinity tolerance. The experiment was conducted using a hydroponic system at optimal growing temperature and photoperiod conditions. The results of the analysis of variance (ANOVA) showed significant effects for salinity treatments and genotypes in terms of all measured traits. Salinity stress significantly increased the root and shoot Na+ contents and root-to-shoot Na+ and K+ translocations. In contrast, other physiological features, gas exchange-related traits, as well as root and shoot biomasses were significantly decreased due to salinity stress. Based on the results of the multi-trait genotype ideotype distance index (MGIDI) as a multiple-traits method, G12 and G14 were identified as the superior salt-tolerant advanced genotypes. In the molecular analysis, salinity stress significantly increased the mean relative expression of HvSOS1, HvSOS3, HvHKT2, HvHKT3, HvNHX1, and HvNHX3 genes by 12.87-, 3.16-, 3.65-, 2.54-, 2.19-, and 3.18-fold more than the control conditions, respectively. The results of heatmap-based correlation and principal component analysis (PCA) revealed a clear association pattern among measured traits and expression data. Indeed, these associations confirmed relationships between tolerance pathways and physiological functions. In conclusion, the genotype G14 (D10*2/4/Productive/3/Roho//Alger/Ceres362-1-1) responded well to salinity stress and showed a better expression pattern of studied genes than other genotypes. Hence, this promising genotype can be a candidate for further assessments before commercial introduction.

Long-day stimulation increases thyroid-stimulating hormone expression and affects gonadal development in chub mackerel

For seasonal breeders, photoperiodic changes are important signals that mark the start of the breeding season. Thyroid-stimulating hormone (TSH) is a glycoprotein hormone that not only promotes the secretion of thyroid hormone but also plays a key role in regulating seasonal reproduction in birds and mammals. However, whether TSH activation has been implicated as a seasonal indicator in fish breeding has not been fully investigated. In this study, we isolated tshb as a starting point to elucidate the effect of photoperiodic changes on the activation of the reproductive axis of chub mackerel. The isolated tshb was classified as tshba, which is widely conserved in vertebrates. The quantitative PCR results showed that tshb was strongly expressed in the pituitary. When female and male chub mackerel with immature gonads were reared for six weeks under different photoperiodic conditions, the gonads developed substantially in the long-day (LD) reared fish compared to those in the short-day reared fish. Real-time PCR results showed that the expression level of tshb in the pituitary gland was significantly elevated in the LD group. Although there was no difference in the gonadotropin-releasing hormone 1 gene expression level in the preoptic area of the brain, follicle-stimulating hormone and luteinizing hormone gene expression levels in the pituitary were also significantly elevated in the LD group. In conclusion, TSH is a potential mediator of seasonal information in the reproductive endocrine axis and may induce gonadal development during the breeding season of chub mackerel.

Transcriptomic and Physiological Analyses Reveal Potential Genes Involved in Photoperiod-Regulated β-Carotene Accumulation Mechanisms in the Endocarp of Cucumber (Cucumis sativus L.) Fruit.

The accumulation of carotenoids in plants is a key nutritional quality in many horticultural crops. Although the structural genes encoding the biosynthetic enzymes are well-characterized, little is known regarding photoperiod-mediated carotenoid accumulation in the fruits of some horticultural crops. Herein, we performed physiological and transcriptomic analyses using two cucumber genotypes, SWCC8 (XIS-orange-fleshed and photoperiod-sensitive) and CC3 (white-fleshed and photoperiod-non-sensitive), established under two photoperiod conditions (8L/16D vs. 12L/12D) at four fruit developmental stages. Day-neutral treatments significantly increased fruit β-carotene content by 42.1% compared to short day (SD) treatments in SWCC8 at 40 DAP with no significant changes in CC3. Day-neutral condition elevated sugar levels of fruits compared to short-day treatments. According to GO and KEGG analyses, the predominantly expressed genes were related to photosynthesis, carotenoid biosynthesis, plant hormone signaling, circadian rhythms, and carbohydrates. Consistent with β-carotene accumulation in SWCC8, the day-neutral condition elevated the expression of key carotenoid biosynthesis genes such as PSY1, PDS, ZDS1, LYCB, and CHYB1 during later stages between 30 to 40 days of fruit development. Compared to SWCC8, CC3 showed an expression of DEGs related to carotenoid cleavage and oxidative stresses, signifying reduced β-carotene levels in CC3 cucumber. Further, a WGCNA analysis revealed co-expression between carbohydrate-related genes (pentose-phosphatase synthase, β-glucosidase, and trehalose-6-phosphatase), photoperiod-signaling genes (LHY, APRR7/5, FKF1, PIF3, COP1, GIGANTEA, and CK2) and carotenoid-biosynthetic genes, thus suggesting that a cross-talk mechanism between carbohydrates and light-related genes induces β-carotene accumulation. The results highlighted herein provide a framework for future gene functional analyses and molecular breeding towards enhanced carotenoid accumulation in edible plant organs.

Развитие свекловичной тли (Aphis fabae Scop.) в зависимости от различных фотопериодических условий

Among the sucking pests of sugar beet crops in Azerbaijan, black bean aphid (Aphis fabae Sсop.), which occurs on beet seedlings from the moment of development of true leaves, causes significant damage. Based on this, the task of our study was to study the main life processes of beet aphids depending on photoperiodic conditions. The work was carried out in the Laboratory of Ecology and Physiology of Insects and the Center for Applied Zoology of Azerbaijan National Academy of Science in 2013–2019. The experiments were carried out in special photo thermostats with automatic control of temperature and light. The results obtained show that the light factor is of secondary importance for the duration of the larval, reproductive periods and for the entire development cycle compared to temperature. It should be noted that winged forms (about 50%) appear in aphid colonies during a 12-hour photoperiod at a temperature of 17 °C. Under the conditions of Azerbaijan, such photoperiod is observed at the end of March and at the beginning of October, when aphids migrate from primary to intermediate plants and vice versa in autumn (early October) from intermediate to primary. The length of the day established in the experiments, which causes the appearance of winged forms, is consistent with the phenology of this species.

Abundance, efficiency, and stability of reference transcript expression in a seasonal rodent: The Siberian hamster.

Quantitative PCR (qPCR) is a common molecular tool to analyse the expression of transcripts in non-traditional animal models. Most animals experience tissue-specific seasonal changes in cell structure, growth, and cellular function. As a consequence, the choice of reference or ‘house-keeping’ genes is essential to standardize expression levels of target transcripts of interest for qPCR analyses. This study aimed to determine the abundance, efficiency and stability of several reference genes commonly used for normalisation of qPCR analyses in a model of seasonal biology: the Siberian hamster (Phodopus sungorus). Liver, brown-adipose tissue (BAT), white adipose tissue (WAT), testes, spleen, kidney, the hypothalamic arcuate nucleus, and the pituitary gland from either long or short photoperiod Siberian hamsters were dissected to test tissue-specific and photoperiod effects on reference transcripts. qPCR was conducted for common reference genes including 18s ribosomal RNA (18s), glyceraldehyde 3-phosphate dehydrogenase (Gapdh), hypoxanthine-guanine phosphoribosyltransferase (Hprt), and actin-β (Act). Cycling time (Ct), efficiency (E) and replicate variation of Ct and E measured by percent coefficient of variance (CV%) was determined using PCR miner. Measures of stability were assessed using a combined approach of NormFinder and BestKeeper. 18s and Act did not vary in Ct across photoperiod conditions. Splenic, WAT and BAT Gapdh Ct was higher in long compared to short photoperiod. Splenic Hprt Ct was higher in long photoperiods. There was no significant effect of photoperiod, tissue or interaction on measures of efficiency, Ct CV%, or efficiency CV%. NormFinder and BestKeeper confirmed that 18s, Gapdh and Hprt were highly stable, while Act showed low stability. These findings suggest that 18s and Hprt show the most reliable stability, efficiency, and abundance across the tissues. Overall, the study provides a comprehensive and standardised approach to assess multiple reference genes in the Siberian hamster and help to inform molecular assays used in studies of photoperiodism.

The effect of the photoperiod on the serotonergic system of the thymus and its role in the ­implementation of the effects of exogenous melatonin

Background. It was believed that the functioning of the immune organs is photoindependent, but there are a number of works that testify to the effect of the photoperiod shift on the functioning of the immune organs. We hypothesized that the absence of a photoperiod under constant light or constant dark would affect the serotonergic system of the thymus gland, as well as the direction and intensity of melatonin exposure.&#x0D; Aim. Study of serotonin-containing thymus cells under conditions of experimental desynchronosis and the role of the photoperiod in the realization of the effects of exogenous melatonin.&#x0D; Material and methods. A comparative study of serotonin-containing thymus cells of 8-week-old Wistar rats, which were divided into 6 groups, was carried out. The first and second groups were kept under conditions of natural photoperiod, the third and fourth in conditions of constant darkening, the fifth and sixth groups in conditions of constant illumination within 4 weeks. Melatonin ad libitum at a concentration of 4 mg/l with water was received by animals of the second, fourth and sixth groups for 4 weeks. To determine the level of serotonin in cells, monoclonal antibodies to 5-HT were used. Conclusions about the serotonin content in the cells were made by measuring the optical density of the substance in 100 cells for each animal using the SigmaScan Pro5 program. Descriptive statistical processing was performed using the Statistica 17 program. The data obtained for each group of animals were averaged, the standard error and standard deviation were calculated.&#x0D; Results. Artificial darkening reduced the serotonin content in 5-HT-immunoreactive cells of the cortical substance by 2.4 times (p=0.001), and constant illumination increased this indicator by 1.9 times (p=0.001). When melatonin was administered to animals kept in dark conditions for 4 weeks, the optical density of serotonin increased by 3.6 times (p 0.0001). Administration of melatonin to animals under constant illumination led to an increase in the optical density of serotonin in the cells of the diffuse endocrine system at the border of the cortex and medulla of the lobules by 1.5 times (p=0.002).&#x0D; Conclusion. The cells of the diffuse endocrine system of the thymus are sensitive to changes in the photoperiod, and the introduction of melatonin has a multidirectional effect on the amount and optical density of serotonin under different light conditions.

ACC1 and ACC2 Genes Expression Microalgae Skletonema costatum On Stress Aeration And fotoperiode In Simultans

Abiotic stresses such as photoperiod, aeration, CO2 concentration, pH, temperature, and salinity can affect and salinity the physiological processes of microalgae. One of the physiological processes that occur is a change in the lipid biosynthetic pathway towards the formation and accumulation of neutral lipids. Neutral lipid accumulation in the form of TAGs. TAGs as one of the defense mechanisms. The regulation of fatty acid biosynthesis is initiated by the ACC1 and ACC2 genes. This study aims to determine the expression of ACC1 and ACC2 genes under conditions of aeration stress and photoperiod simultaneously in microalgae Skeletonema costatum. The method used was the analysis of gene expression in the sample of S. costatum RNA extract using qRT-PCR. Based on the results of the study, it was found that the ACC1 gene was expressed and upregulated in the A2F2 treatment (24-hour aeration and 24:0 photoperiod) with a CT value of 36.85 while the ACC2 gene was expressed and upregulated in the A1F1 treatment (12-hour aeration and 12:12 photoperiod). with the CT value of 36,874.

Knockouts of positive and negative elements of the circadian clock disrupt photoperiodic diapause induction in the silkworm, Bombyx mori

Diapause is one of the most important traits that have sustained insects to thrive. To survive harsh seasons, most insects can arrest their development and enter diapause. The photoperiod is the signal that indicates insects the proper timing to enter diapause. Circadian clock genes are shown to be involved in photoperiodic diapause induction in various insect species. The silkworm, Bombyx mori, enters diapause at the embryonic stage. In bivoltine strains, diapause determination is under maternal control and affected by temperature and photoperiodic conditions that mothers experienced during embryonic and larval stages. Two independent studies showed that knocking out the core clock gene, period, perturb photoperiodic diapause induction in B. mori. However, whether the circadian clock as whole or individual clock genes are responsible for the photoperiodic diapause induction remains unknown. In this study, using CRISPR/Cas9 we knocked out negative (period and timeless) and positive elements (Clock and cycle) in p50T, a bivoltine strain which exhibits photoperiodic diapause induction during both embryonic and larval stages. The temporal expression patterns of clock genes changed in each core clock gene knockout strain, suggesting disruption of normal feedback loops produced by circadian clock genes. Furthermore, the ability of female moths to appropriately produce diapause or non-diapause eggs in response to photoperiod in both embryonic and larval stages was lost in all knockout strains. Our results indicate the involvement of circadian clock in photoperiodic diapause induction in B. mori.

Identification of the &lt;i&gt;eam8&lt;/i&gt; allele associated with photoperiod insensitivity in barley accessions from Japan

BACKGROUND: Cultivated plants grown in the northern regions of Russia are subject to strict requirements in terms of their ability to produce a high yield during short growing season. Important adaptive traits that affect crop yield are early maturity and insensitivity to photoperiod. The search and involvement in breeding programs of new sources of these valuable traits is a necessary step for the creation of new ecologically plastic varieties.&#x0D; THE AIM: To identify alleles of the Eam8 gene, which determine weak photoperiodic sensitivity, among Japanese barley accessions from the N.I. Vavilov All-Russian Institute of Plant Genetic Resources (VIR) collection.&#x0D; MATERIALS AND METHODS: Screening of 200 barley accessions from Japan was carried out in a climatic chamber in order to identify plants with yellow color of seedlings a marker sign of the influence of the eam8 allele, which controls early maturity and low sensitivity to the photoperiod. The presumably photoperiod-insensitive accession was studied under conditions of long and short photoperiods and was studied by molecular methods.&#x0D; RESULTS: Phenotypic screening identified a presumably photoperiod-insensitive accession k-17545 (Jap.456). The photoperiodic sensitivity of the accession and the variety Mari (carrier of the recessive eam8 allele) were similar. Using molecular analysis, the eam8.k allele, occurred naturally in the cultivars Kinai 5 and Kagoshima Gold from Japan, was found in the k-17545 line. The Jap.456 was polymorphic by srorage proteins (hordein) patterns and RAPD profiles. In addition, previously undescribed SNPs in the eam8.k sequence were identified in individual plants.&#x0D; CONCLUSIONS: As a result of the study of 200 accessions of barley from Japan, accession k-17545 (Jap.456) was found, in which the eam8.k allele was identified, which controls weak sensitivity to the photoperiod.

Copper formulations in bacterial blight control and toxic effects on coffee seedlings

Bacterial blight of coffee (Pseudomonas syringae pv. garcae) is an important coffee disease and can be controlled using antibiotics and copper-based compounds. However, copper-based compounds raise doubts among coffee growers regarding bacterial blight control efficiency and phytotoxic potential. In this work, coffee plants were sprayed with different copper molecules in order to study their efficiency on bacterial blight control and the phytotoxic potential. Seven copper formulations, cuprous oxide, copper oxychloride, copper nitrate, copper hydroxide 1 (water-dispersible granules) and 2 (concentrated suspension), copper sulfate 1 (complexed with gluconic acid) and 2 (Bordeaux mixture) were studied. The copper formulations efficiency was compared with the antibiotic kasugamycin, saline solution, and control. In controlled environmental conditions of temperature, relative humidity, and photoperiod, coffee seedlings were sprayed with the treatments and after 24 hours they were inoculated with Pseudomonas syringae pv. garcae suspension. Disease incidence and severity assessments were performed in a 2-day interval during a 16-day period. Phytotoxicity incidence and severity, mapping, and quantification of copper on the leaf tissue surface, dried leaves weight, and total copper leaf content were assessed 16 days after pathogen inoculation. Data were submitted to the Scott-Knott test (p &lt; 0.05). Cuprous oxide and copper sulfate 2 proved most efficient to bacterial blight control, causing lower phytotoxicity effect, best covering, and persistence on leaf tissues. Copper nitrate and copper sulfate complexed with gluconic acid were more phytotoxicity compared to other copper formulations.

Annual changes in ovarian development stages of farmed female red‐spotted grouper, Epinephelus akaara, and inducing sexual maturity using photoperiod manipulation

AbstractThis study aimed to investigate the correlation between melatonin and the reproductive mechanism of farmed female red‐spotted groupers, Epinephelus akaara. Through the reproductive cycle experiment, the sexual maturity period was determined to be from June to July, following which the spawning season occurred in August. In addition, kiss1, kiss2, and GPR54 mRNA expression levels peaked in January, whereas that of sbGnRH mRNA remained at high levels from January to May and decreased during the sexual maturity and spawning seasons. During the day–night cycle, a nocturnal rhythm of AANAT2 mRNA expression was observed in the brain, and AANAT2 mRNA expression showed a seasonal pattern with increased expression during summer compared with that in winter. A correlation between melatonin and reproduction‐related genes could not be observed via melatonin administration, and sexual maturity was observed to be more induced under long photoperiod conditions compared with short photoperiod conditions. These results indicate that the reproductive mechanism of the farmed female red‐spotted grouper is related to changes in photoperiod and melatonin, and further research is needed to clarify the reproductive mechanism. Our findings provide basic information for identifying the reproductive mechanisms of farmed E. akaara.