The relationship between resource abundance and insect herbivory on islands

We examined the relationship between resource abundance and the feeding activity of phytophagous insects on three common island plants. The aim was to investigate the correlation between phytophagous insects’ abundance and availability of food and island geography. We collected 30,835 leaves from three tree species groups (Mallotus japonicus, Prunus species, and Quercus species) on 18 islands in southwest Korea. The number of plant resources for herbivores varied: the number of leaves per shoot was the highest in Mallotus, leaf weight and the water content per leaf was significantly lower in Quercus species. External feeding was higher for Prunus and Quercus species, whereas the internal feeding type was significantly higher for Quercus species. Geography (area and distance), elevation and food resource (elevation, number of plant species, and the forest cover rate) had a variable effect on phytophagous insects feeding activities: distance and the number of plant species were more explainable to the external feeding guild. In contrast, area and forest cover were more to the internal feeding guild.

Generation of Circularly Polarized Quasi-Non-Diffractive Vortex Wave via a Microwave Holographic Metasurface Integrated with a Monopole

In this paper, a novel method for generating a circularly polarized (CP) quasi-non-diffractive vortex wave carrying orbital angular momentum (OAM), based on the microwave holographic metasurface integrated with a monopole, is proposed. This method is the combination of the non-diffraction theory and the principle of waveguide-fed-based holography and is equivalent to a superposition of two scalar impedance modulation surfaces. To verify the proposed method, a holographic metasurface generating a left-handed circularly polarized (LHCP) quasi-non-diffractive vortex wave carrying −1 mode OAM at the normal direction, was simulated and analyzed. The metasurface consisted of inhomogeneous slot units on a grounded substrate and a monopole excitation. Moreover, the location distribution of slots was determined by a computed interferogram between the reference wave and the object wave with the non-diffractive feature. Compared with an ordinary vortex wave, the quasi-non-diffractive wave obtained by our proposed method possessed a smaller divergence radius and a stronger electric field strength in the 9 times wavelength range. It paved a new path for manipulating the non-diffractive vortex wave in medium distance without using an external feeding source, which holds great potential for the miniaturization devices applied in medium-distance high-capacity secure communication, high-resolution imaging and intelligent detection.

Эмбриональное и раннее личиночное развитие бурого терпуга Hexagrammos octogrammus (Scorpeniformes: Hexagrammidae) северной части Охотского моря

The roe of Hexagrammos octogrammus from of the Northern part of the Sea of Okhotsk was incubated in an experiment. A detailed description of the morphology of the species development, from fertilization of eggs to the fry transition to external nutrition, accompanied by microphotographs of eggs and larvae fry in vivo, is given. It was established that the fertilized eggs of H. octogrammus from the northern part of the Sea of Okhotsk are 1.75 mm in diameter with fluctuations of 1.61-1.98 mm. Hatching of embryos occurs after 33.5 days of incubation at an average temperature of 11.5°C. Hatched yolk fry is 7.78 mm (7.15-8.06 mm) of TL (Total length) and 7.39 mm (6.83-7.68 mm) of SL (Standard length). Upon reaching TL of 8.74 mm (8.14-9.26 mm) and SL of 8.21 mm (7.63-8.86 mm), the fry switch to external feeding. The regional features of the masked greenling pigmentation in early ontogenesis are revealed.

Cutin Synthesis in Developing, Field-Grown Apple Fruit Examined by External Feeding of Labelled Precursors

An intact skin is essential in high-quality apples. Ongoing deposition of cuticular material during fruit development may decrease microcracking. Our objective was to establish a system for quantifying cutin and wax deposition in developing apple fruit. Oleic acid (13C and 14C labelled) and palmitic acid (14C labelled) were fed to developing apples and the amounts incorporated in the cutin and wax fractions were quantified. The incorporation of 14C oleic acid (C18) was significantly higher than that of 14C palmitic acid (C16) and the incorporation in the cutin fraction exceeded that in the wax fraction. The amount of precursor incorporated in the cutin increased asymptotically with time, but the amount in the wax fraction remained about constant. Increasing the concentration of the precursor applied generally increased incorporation. Incorporation in the cutin fraction was high during early development (43 days after full bloom) and decreased towards maturity. Incorporation was higher from a dilute donor solution (infinite dose feeding) than from a donor solution subjected to drying (finite dose feeding) or from perfusion of the precursor by injection. Feeding the skin of a developing apple with oleic acid resulted in significant incorporation in the cutin fraction under both laboratory and field conditions.

Morpho- Functional Observations on Ontogenic development of the Renal excretory system in pre to post flexion stages larvae of Himalaya Snow trout Schizothorax plagiostomus (Heckel)

Schizothorax plagiostomus is one of the most important food fish inhabiting the snow-fed tributaries of the Himalayan region. Due to nutritional value, good growth rate, high economic prospects as well as the decline in the natural habitat its commercial production is desired. Keeping in view this fact, during the present investigation by following the artificial breeding and rearing experiments an attempt has been made to understand the morpho-functional development of the renal excretory system in pre to post-flexion stages larvae. The study reveals that all the essential basic structures of the renal excretory system (pronephros) were established before the initiation of external feeding. During the post-flexion stage when the yolk sac was almost reabsorbed and larvae exclusively depend on exogenous feeding the mesonephric tubules were forming and some of them become functional i.e. presence of glomerulus to maintain the internal environment as well as efficient removal of gradually increasing amount of nitrogenous wastes. The presence of lymphoid tissues was suggesting that cell-mediated immune responses develop progressively in the Himalayan snow trout S. plagiostomus larvae.

Variasi Pemberian Bioton terhadap Kelimpahan Moina sp.

Fish after the egg-bag absorption phase require external feeding, in the form of fresh natural food organisms, such as phytoplankton, zooplankton, or aquatic insect larvae. These natural food organisms are limited in number. The business of mass production of natural food is still limited to several types originating from marine or brackish waters. For this type of natural freshwater fish feed, it is still limited to experimental materials. This study aims to determine the best dosage of Bioton liquid fertilizer added to the maintenance medium to the rate of population abundance of Moina sp. The research was conducted at the Wet Laboratory of Fisheries Cultivation Study Program, Faculty of Agriculture, Ahmad Yani University, Banjarmasin. The method used in this study was an experiment with a completely randomized design of 4 treatments and 3 replications. The treatment applied was 4 treatments with 3 repetitions, with the following treatment of Bioton liquid fertilizer: A = 5 ml / 3 l water, B = 10 ml / 3 l water, C = 15 ml / 3 l water, and D = without Bioton liquid fertilizer (control). The results showed that the abundance of Moina sp in treatment A = 4,333 ind / l, B = 3,633 ind / l, C = 2,700 ind / l and D = 3,034 ind / l. The ANOVA test results of all treatments were very significantly different, so accept H1, namely giving bioton with different doses had a significant effect on the abundance of Moina sp. The results of the LSD test of all treatments had a very significant difference in abundance, except for treatment D to treatment C which was significantly different, with the best treatment being a dose of 5 ml / 3 l of water (treatment A).

Postembryonal ontogenesis of broad whitefish and formed herd under phenol intoxication

The paper reveals the data on comparative analysis of broad whitefish Coregonus nasus larvae in the Ob received from natural populations (lower Ob) and from fish, farmed outside their natural habitat. This fish herd was formed from fish brought from the lower Ob basin to the fish farm “Forvat” (Leningrad region), where they were bred during five generations. During a month, the embryos of broad whitefish were incubated in the conditions of Sob fish-breeding plant (Harp village, Yamalo-Nenetsk Autonomous District), then they were placed for breeding into the laboratory of the Institute of Biology of Tyumen State University. The broad whitefish embryos from artificial herd were taken to the laboratory at the stage of eye pigmentation. After hatching, the larvae in both series were found to be chronically intoxicated with phenol 1 (0.001 mg/l), 5 (0.005 mg/l) and 10 (0.01 mg/l) since their transfer to external feeding up to two months of age. The authors observed broad whitefish from artificial herd and found out increased survival rate, higher balance and lower level of hystopathological changes in all variants. Due to low biological parameters of the broad whitefish young stock, their application for stocking natural basins in the conditions of modern anthropogenic impact is not efficient. On the other hand, increased biological and toxicovigilance characteristics are more effective when being applied in the basins with high anthropogenic load with the aim to increase fish productivity.

Genetic and epigenetic regulation of zebrafish intestinal development

Many regulatory pathways are conserved in the zebrafish intestine compared to mammals, rendering it a strong model to study intestinal development. However, the (epi)genetic regulation of zebrafish intestinal development remains largely uncharacterized. We performed RNA-sequencing and chromatin immunoprecipitation (ChIP)-sequencing for activating (H3K4me3) and repressive (H3K27me3) chromatin marks on isolated intestines at 5, 7, and 9 days post-fertilization (dpf), during which zebrafish transit from yolk dependence to external feeding. RNA-sequencing showed the enrichment of metabolic maintenance genes at all time points and a significant increase in lipid metabolism between 5 and 9 dpf. A strong correlation was observed between gene expression and presence of chromatin marks on gene promoters; H3K4me3-marked genes were expressed higher than H3K27m3-marked genes. Next, we studied a key epigenetic player, Enhancer of zeste homolog 2 (Ezh2). Ezh2 places the repressive H3K27me3 mark on the genome and is highly conserved in vertebrates. We used the nonsense mutant allele ezh2(hu5670) to study the effect of ezh2 loss on intestinal development. These mutants survived gastrulation and died around 11 dpf, showing severe morphological defects in the intestine and liver, accompanied by decreased intestinal (fabp2) and hepatic (fabp10a) marker expressions. Our results suggest that Ezh2 is essential for proper intestinal tissue maintenance and overall survival.