Silk fibroin hydrolysate exerts an anti-diabetic effect by increasing pancreatic β cell mass in C57BL/KsJ-db/db mice

Components of silk including silk fibroin have long been used as anti-diabetic remedies in oriental medicine. However, detailed mechanisms underlying these anti-diabetic effects remain unclear. In this study, we examined the anti-diabetic activity of silk fibroin hydrolysate (SFH) in C57BL/KsJ-db/db (db/db) mice, a well-known animal model of non-insulin dependent diabetes mellitus. When the db/db mice were administered SFH in drinking water for 6 weeks, hyperglycemia in the animals gradually disappeared and the level of glycosylated hemoglobin decreased, indicating that SFH plays important role in reducing the symptoms of diabetes. In addition, SFH-treated db/db mice exhibited improved glucose tolerance with increased plasma insulin levels. Immunohistochemical and morphological analyses showed that SFH up-regulated insulin production by increasing pancreatic β cell mass in the mice. In summary, our results suggest that SFH exerts anti-diabetic effects by increasing pancreatic β cell mass in a non-insulin dependent diabetes mellitus mouse model.     

Using new egg parasitoids (Trichogramma spp.) to improve integrated management against Tuta absoluta

This study is the first step of the TutaPI program (2011–13) to decrease the costs of Integrated Pest Management (IPM) strategies against Tuta absoluta in France by investigating new beneficial insects. Currently, the association of predator/egg parasitoid (Macrolophus pygmaeus and Trichogramma achaeae, respectively) in IPM strategies are quite effective, but expensive. Sixty‐four new potential strains from 19 Trichogramma species originating from different regions of the world (from the collection of Trichogramma at INRA Provence Alpes Côte d'Azur (PACA), France) were studied in this work. A screening study was performed on T. absoluta eggs on isolated tomato leaves (for 24 h at 25 ± 1°C, RH 75 ± 5% and 16 h light : 8 h dark). The proportion of parasitized T. absoluta eggs varied greatly (between 0 and 73%) depending on the different strains used. Levels of parasitism by females, equal to or higher than that of T. achaeae, were observed in 14 of the strains tested among eight species (four from France, four from elsewhere in Europe). The proportion of females that parasitized T. absoluta eggs was significantly different between strains (from 0 to 100%). Experimental results allowed about half of the 64 initial strains to be eliminated before the next steps: tests on a larger scale (mesocosm, and then in the greenhouse and field).     

Sedative and anticonvulsant effects of hydroalcoholic extract of Equisetum arvense

The hydroalcoholic extract of Equisetum arvense (HAE) tested at the doses of 200 and 400 mg/kg showed a significant activity on the open-field, enhanced the number of falls in the rota-rod reducing the time of permanence in the bar and increased the sleeping time (46% and 74%) in the barbiturate-induced sleeping time. In the pentylenetetrazole-seizure, it increased the first convulsion latency, diminished the severity of convulsions, reduced the percentage of animals which developed convulsion (50% and 25%) and protected animals from death. On the contrary, in the elevated plus maze, the doses 50, 100 and 150 mg/kg did not affect the evaluated parameters. Thus, HAE presented anticonvulsant and sedative effects. Phytochemical analysis detected the presence of tannins, saponins, sterols and flavonoids.     

Membrane partitioning of organophosphorus and organochlorine insecticides and its implications for mechanisms of toxicity

Partition coefficients of organophosphorus and organochlorine insecticides were determined in several types of membrane. Insecticide partitioning varied among the membranes under study, depending on temperature, cholesterol content and on the physico-chemical profiles of membrane components and the insecticides themselves. The maximal partitions for DDT, lindane, parathion and malathion in egg phosphatidylcholine bilayers over the temperature range from 10 to 37°C (at which the lipid is in the liquid-crystalline state) were about 260000, 2000, 1000 and 120, respectively. Incorporation of 50 mol% cholesterol in egg phosphatidylcholine bilayers dramatically decreased the partition and almost abolished the temperature effect. First-order phase transitions of dimyristoyl-, dipalmitoyl- and distearoylphosphatidylcholines (DMPC, DPPC and DSPC) were accompanied by a sharp increase in insecticide partition. Furthermore, the insecticides under study were more easily accommodated in bilayers of short-aliphatic-chain lipids, since higher values of partition were obtained in DMPC bilayers. Partition values in native membranes depended considerably on the membrane type and composition and were higher in sarcoplasmic reticulum (SR) and mitochondria than in brain microsomes, myelin and erythrocytes. Identical results were obtained in related liposomes of total extracted lipids, although the absolute partitions showed decreased values. In general, the incorporation of insecticides correlated reasonably with the cholesterol content of the membranes. The order of partitioning of the above insecticides did not run parallel with their toxicity to mammals and, both in model and in native membranes, followed the sequence: DDT ? lindane > parathion > malathion.     

Distribution and genetic diversity of Dothistroma septosporum in Pinus brutia forests of south-western Turkey

Dothistroma needle blight (DNB) is a serious disease of the Pinaceae, mainly Pinus species, caused by the fungi Dothistroma septosporum and D. pini. Both species are regarded as invasive forest pathogens worldwide, with rising incidence in central and northern Europe over the last three decades. In this work, 29 sites were investigated between 2013 and 2015 in south-western Turkey. Morphological examination of needles confirmed DNB infection (i.e., Dothistroma conidiospores observed) at 18 sites, and a total of 108 Dothistroma sp. isolates were obtained from 11 of the sites. Host age seemed to be an important factor in both occurrence and severity of DNB in Pinus brutia forests. Continuous rainy days, especially in December, may increase severity of disease; however, extreme rain events may reduce available conidiospores on plant tissues or in the air. Species-specific mating type primers showed that all isolates were D. septosporum; D. pini was not detected. The mating type ratio was close to 1:1, indicating sexual recombination was occurring. Eleven microsatellite markers revealed 59 unique multilocus haplotypes (MLHs) among the 73 isolates originating from different conidiomata. The majority of MLHs were represented by a single isolate (n = 52) and only one MLH was shared between two localities. Analyses showed high genetic diversity, isolation-by-distance, and clear population clusters. These findings suggest that D. septosporum is well established in south-western Turkey and is probably not a recent introduction.     

Pattern of inheritance of a self-fertility gene in an autotetraploid perennial ryegrass (Lolium perenne) population

A mutation causing self-fertility (SF) in perennial ryegrass was studied at the tetraploid level. The aim of this work was to determine a) whether SF remains functional in a tetraploid population and b) whether the SF mutation expresses dominance in heterozygous pollen grains. A tetraploidized plant carrying SF alleles was self-pollinated to create a segregating F₂ population. In the F₂ individuals, pollen compatibility ranged between 38% and 84% showing that SF remained functional. The SF locus genotype was the main determinant of pollen compatibility explaining 78% of the variation. The observed segregation was significantly different from the expected under both SF being dominant or recessive models (P_(χ2)≤0.001) and tended to be intermediate between them, indicating partial dominance or additive gene action. The frequency of the different genotypes suggested that pollen grains homozygous for the mutation have a competitive advantage over heterozygous pollen and that pollen compatibility is affected by the interaction with additional loci. The implications of our results for breeding polyploid grasses are discussed.     

Complete genome sequence and pathogenic analysis of a new betanodavirus isolated from shellfish

We determined the complete genomic RNA sequence of a new type of betanodavirus Korea shellfish nervous necrosis virus (KSNNV) isolated from shellfish. Compared with other isolates representing four genotypes of betanodaviruses, the identity of the whole nucleotide sequence of the virus was in the range of 76%–83% with the presence of specific genetic motifs and formed a separate new branch in the phylogenetic analysis. In pathogenic analysis by immersion method, KSNNV‐KOR1 shows 100% cumulative mortality like SFRG10/2012BGGa1 (RGNNV) in newly hatched sevenband grouper and mandarin fish, which is clearly different from those found in negative control groups. There were no significant differences in increasing rates of mortality and viral intra‐tissue concentration of larval fishes infected with KSNNV‐KOR1 at both 20 and 25°C water temperature. Histopathological examination of each fish species in the moribund stage revealed the presence of clear vacuoles in both brain and retinal tissues similar to typical histopathology features of RGNNV. In the present study, we first report a new betanodavirus from shellfish as the aetiological agent of viral nervous necrosis disease in fish with complete genomic nucleotide sequence and pathogenic analysis.     

Possible effects of the recent Australian ban on prawn imports

Australia banned imports of uncooked prawns from Asia in early 2017 after an outbreak of the deadly white spot disease in southern Queensland. The ban expired after 6 months, and it remains unclear what the source of the epidemic was, or the mechanism through which it may have entered the country. The Queensland State Government offered financial assistance to selected producers, although as a group, producers benefit from the higher prices resulting from the ban. In fact, the major cost of the ban is borne by domestic consumers and foreign producers. The major impact is a transfer from Australian consumers to Australian producers. These transfers are quantified in this analysis, as are the impacts on developing country exporters.     

Zoogeographical barriers causing discontinuous osteometrical variations in the northern treeshrew skulls

Morphological variation of the skull was examined in the northern treeshrew (Tupaia belangeri) from various localities across Southeast Asia. Through a multivariate analysis, the treeshrews from South Vietnam exhibited distinct morphological characteristics compared to other populations from Thailand and Laos, and Malaysia. The plots of the specimens of North Vietnam are not randomly mixed with Thailand plots segregation in the scatteregrams of canonical discriminant analysis. Since the skulls of the population from North Vietnam were morphologically similar to those form central Laos and northern and northeastern Thailand, the zoogeographical barrier effect of Mekong River was not clearly confirmed. The population of the Kanchanaburi in western Thailand is clearly smaller in size compared to the other populations. The southern border of the distribution of this species is determined by the Isthmus of Kra or Kangar-Pattani Line. In the northern treeshrew, which is distributed from southern China to Bangladesh and southern Thailand, we have detected osteometrical geographical variation driven by geography. These results indicate that the skull morphology in the Tupaia glis-belangeri complex distinctively differs in South Vietnam, western Thailand, and southern Thailand. The zoogeographical barrier and factor separating these districts are expected to clarify in the future.