Glyphosate‐resistant Italian ryegrass (Lolium multiflorum) on rice paddy levees in Japan

The rapid range expansion of naturalized Italian ryegrass (Lolium multiflorum Lam.) in farmland is a serious problem in Fukuroi city in Shizuoka Prefecture, Japan. Glyphosate has been used to control Italian ryegrass in the levees of rice paddy fields and wheat fields for ～20 years, but this weed in Fukuroi city is poorly controlled by glyphosate. In order to elucidate the level of resistance to glyphosate in Italian ryegrass populations, seed bioassays and a foliar application experiment, using seeds collected from 16 wild populations in and around Fukuroi city and from three susceptible cultivars, were conducted. For the susceptible cultivars and one population from a site where glyphosate had not been applied for >10 years, the shoot length in the seed bioassays was greatly suppressed at a glyphosate concentration of 10 mg ai L^?1 and no seedling survived after the foliar application of glyphosate at a rate of 2.3 kg ai ha^?1. Nine wild populations from levees in the southern part of Fukuroi city showed vigorous shoot growth at a glyphosate concentration of 10 mg ai L^?1 and had at least a 78% survival rate after the application of glyphosate at 2.3 kg ai ha^?1. Four wild populations from levees in the northern part of Fukuroi city showed a slight suppression of the shoot growth as a result of the glyphosate treatment and their survival rates ranged from 20 to 64%. The results suggested that resistance to glyphosate has evolved in the wild populations of Italian ryegrass that are growing on the levees. This is the first report of a glyphosate‐resistant weed in Japan.     

Resistance levels of sulfonylurea‐resistant Schoenoplectus juncoides (Roxb.) Palla with various Pro197 mutations in acetolactate synthase to imazosulfuron,bensulfuron‐methyl,metsulfuron‐methyl and imazaquin‐ammonium

An investigation, using herbicidal pot tests in a greenhouse condition, was conducted to determine the whole‐plant dose–response relationships to several acetolactate synthase (ALS)‐inhibiting herbicides of sulfonylurea (SU)‐resistant Schoenoplectus juncoides with various Pro₁₉₇ mutations in ALS that was collected from Japanese rice paddy fields. All the tested SU‐resistant accessions with a Pro₁₉₇ mutation were highly resistant to two commonly used SU herbicides (imazosulfuron and bensulfuron‐methyl), but were much less resistant to another SU herbicide, metsulfuron‐methyl, and were substantially not resistant to imazaquin‐ammonium. These cross‐resistance patterns have been known previously in fragments of S. juncoides and other weed species and were comprehensively confirmed in this study with a whole set of Pro₁₉₇ mutations. The analyses of resistance levels, based on ED₉₀ values, newly showed that different accessions with a common amino acid substitution in ALS1 showed similar responses to these herbicides (confirmed with four amino acid substitutions), that the rankings of resistance levels that were conferred by various Pro₁₉₇ mutations in ALS1 differed among the SU herbicides and that the resistance levels of the ALS2‐mutated accessions were higher than, lower than or similar to those of the corresponding ALS1‐mutated accessions, depending on the compared pair, but the deviation patterns were generally similar among the SU herbicides in each compared pair. The final finding might suggest that the abundance of ALS2 is not as stable as that of ALS1. In addition, as a result of these new findings, together with expected further research, a suggested possibility is that substituting amino acids at Pro₁₉₇ generally could be estimated by plotting each accession's ED₉₀ values of imazosulfuron and bensulfuron‐methyl in a two‐dimensional graph.     

Altitudinal life-cycle and body-size variation in ground beetles of the genus Carabus (subgenus Ohomopterus) in relation to the temperature conditions and prey earthworms

The body size of univoltine insect species generally decreases with increasing altitude or latitude. This pattern may have arisen from adaptations to multiple factors that potentially affect body-size variation, such as temperature, food, and interspecific interactions. We examined altitudinal variations in life history and body size, and their relationships to temperature and food resources in two ground beetle species of the genus Carabus (subgenus Ohomopterus; C. tosanus and C. japonicus) in a mountainous area (altitude 860–1730 m) of Shikoku Island, Japan. Larvae of these species are specialist predators of earthworms. The body size of C. tosanus decreased with an increase in altitude. Carabus japonicus, which is much smaller than C. tosanus, exhibited similar sizes across altitudes, although it was not abundant at high altitudes. Available cumulative temperatures for larval development were limited at higher altitudes, and C. tosanus started reproducing 1 month earlier at higher than at lower altitudes. Earthworms (larval food) were less abundant at higher than at lower altitudes. This may imply that food resources also restrict the optimal body size of C. tosanus at higher altitudes.     

Biallelic inactivation of BRCA2 in Fanconi anemia

Fanconi anemia (FA) is a rare autosomal recessive cancer susceptibility disorder characterized by cellular hypersensitivity to mitomycin C (MMC). Six FA genes have been cloned, but the gene or genes corresponding to FA subtypes B and D1 remain unidentified. Here we show that cell lines derived from FA-B and FA-D1 patients have biallelic mutations in BRCA2 and express truncated BRCA2 proteins. Functional complementation of FA-D1 fibroblasts with wild-type BRCA2 complementary DNA restores MMC resistance. Our results link the six cloned FA genes with BRCA1 and BRCA2 in a common pathway. Germ-line mutation of genes in this pathway may result in cancer risks similar to those observed in families with BRCA1 or BRCA2 mutations.     

Isolation and characterization of the rbcS genes from a sterile mutant of Ulva pertusa (Ulvales,Chlorophyta) and transient gene expression using the rbcS gene promoter

We isolated two different genomic DNAs (UprbcS1 and UprbcS2) encoding the small subunit of ribulose-1,5-bisphosphate carboxylase/oxygenase and portions of the 5′- and 3′-flanking regions from sterile Ulva pertusa Kjellman. The UprbcS1 and UprbcS2 genes had three introns in the coding region. Each predicted UprbcS polypeptide was a 180-amino-acid (AA) residue including a 38-AA transit peptide, although the 104th AA residue was replaced. The nucleotide sequences of UprbcS cDNAs isolated from a cDNA library corresponded to that of the UprbcS1 gene, suggesting that the UprbcS1 gene was predominantly expressed in sterile U. pertusa compared to UprbcS2. Southern blot analysis showed that each UprbcS gene was a single-copy gene in the sterile U. pertusa genome. Northern hybridization indicated that the expression of UprbcS was induced and repressed by dark and light treatments, respectively. When sterile U. pertusa cells were transformed with an expression vector containing the UprbcS1 promoter and terminator sequences fused with the green fluorescent protein (GFP) gene, GFP fluorescence was observed in the cells transformed. These results suggest that the UprbcS1 gene promoter is light regulated and highly active in the sterile U. pertusa cells and is available for genetic transformation system in the alga.     

Genetic population evaluation of two closely related flatfish species, the rare barfin flounder and spotted halibut, along the Japanese coast

ABSTRACT:   Barfin flounder and spotted halibut have been selected as target species for stock enhancement in Japan. Understanding the genetic condition of the wild stock is a principal requirement in any stock enhancement program. The genetic variability of barfin flounder and spotted halibut, and the population structure of spotted halibut were evaluated using microsatellite DNA markers (msDNA) and the control region of the mitocondrial DNA (mtDNA). Barfin flounder and spotted halibut showed high genetic variability at the msDNA level. Barfin flounder A was 16.7 and H _e was 0.860; spotted halibut A _n ranged from 7.7 to 10.2 and H _e ranged from 0.710 to 0.774. At the mtDNA level, high haplotype ( h  = 0.922) and low nucleotide (π = 0.002) diversities were observed for barfin flounder; however, low haplotype and nucleotide diversities ( h  = 0.603–0.620 and π = 0.001–0.002), and very low haplotype and nucleotide diversities ( h  = 0.193 and π = 0.0003) were observed for spotted halibut in the north and south locations, respectively. Slight genetic differentiation among spotted halibut sampling locations was observed from the msDNA. MtDNA analyses showed genetic differentiation between north and south locations, but not within them. The designation of north-specific and south-specific management units in the future stock enhancement activities of spotted halibut is recommended.     

Draining system and feeding rate during the initial development of Lophiosilurus alexandri (Steindachner, 1877), a carnivorous freshwater fish

This study evaluated the efficiency of the drainage system during the larviculture of Lophiosilurus alexandri. Moreover, we assessed the best feeding rate after feed training for juvenile production. The study was performed in three phases over 87 days. In phase 1 (40 days), larvae were fed live food and posteriorly submitted to feed training in two drainage systems: water drained on the surface (DS), and water drained into a tank column (DI). In the second phase (30 days), using only the DS system juveniles were fed a formulated diet at feeding rates, 2, 4, 6 and 8% of body wet weight. In the third phase (17 days), the fish from the second phase were fed until apparent satiation. At the first phase, the animals in the DS system exhibited greater survival rates and growth. The best feeding rate for daily weight gain, specific growth rate (SGR) and mean body weights were similar: 5.57, 5.13 and 5.68% respectively. In the third phase, an increased SGR was observed in the treatment groups that received lower feeding rates in the second phase (2 and 4%), which could indicate a possible compensatory growth rate.