Effect of high temperature pre-treatment on elongation of the mesocotyl of rice seedlings I. Cell multiplication in the mesocotyl

Mesocotyl elongation in paddy rice seedlings of the japonicatype was markedly stimulated by high temperature pre-treatmentof seeds. Examination of the number of parenchyma cells perone cell layer in longitudinal sections of mesocotyl revealedthat stimulation may be mainly caused by cell multiplication. (Received February 24, 1970; )     

Association mapping for partial resistance to Phytophthora sojae in soybean (Glycine max (L.) Merr.)

Association mapping is a powerful high-resolution mapping tool for complex traits. The objective of this study was to identify QTLs for partial resistance to Phytophthora sojae. In this study, we evaluated a total of 214 soybean accessions by the hypocotyl inoculation method, and 175 were susceptible. The 175 susceptible accessions were then evaluated for P. sojae partial resistance using slant board assays. The 175 accessions were screened with 138 SSR markers that generated 730 SSR alleles. A subset of 495 SSR loci with minor allele frequency (MAF) ≥ 0.05 was used for association mapping by the Tassel general linear model (GLM) and mixed linear model (MLM) program. This soybean population could be divided into two subpopulations and no or weak relatedness was detected between pairwise accessions. Four SSR alleles, Satt634-133, Satt634-149, Sat_222-168 and Satt301-190, associated with partial resistance to P. sojae were detected by both GLM and MLM methods. Of these identified markers, one marker, Satt301, was located in regions where P. sojae resistance QTL have been previously mapped using linkage analysis. The identified markers will help to understand the genetic basis of partial resistance, and facilitate future marker-assistant selection aimed to improve resistance to P. sojae and reduce disease-related mortality in soybean.     

Effect of Pituitary and Ovarian Hormones on Human Melanocytes In Vitro

Normal human melanocytes in culture became enlarged and dendritic after a 2-day incubation with either the pituitary (β-MSH, a potent analog of α-MSH, ACTH, FSH and LH) or the ovarian (estradiol, estriol and progesterone) hormones. Under the same experimental conditions, pituitary hormones also increased both the tyrosinase activity and tyrosinase-related protein-1 (TRP-1) while ovarian hormones increased TRP-1 but not tyrosinase activity. The results suggest that pituitary and ovarian hormones possibly induce hyperpigmentation of the skin by stimulating the melanogenesis in epidermal melanocytes, and that estradiol and progesterone may be involved in the pathogenesis of melasma (chloasma) usually developing between early adulthood and menopause in which a high concentration of serum ovarian hormones was maintained.     

Genetic analysis of feeding preference in two related species of Altica (Coleoptera: Chrysomelidae: Alticinae)

Abstract 1. Genetic analysis of feeding preference can make an important contribution to our understanding of the evolution of host‐plant selection in phytophagous insects. Two closely related flea beetles, Altica viridicyanea (Baly) and Altica fragariae Nakane, with separate host plants [Geranium wilfordii Maxim. and Duchesnea indica (Andrews) Focke respectively] were hybridised to analyse the inheritance mode of feeding preference. 2. Adult hybrid F₁ (A. viridicyanea female × A. fragariae male) preferred G. wilfordii to D. indica in two‐choice tests, regardless of which plant they had fed on as larvae. Adults of one backcross to A. fragariae preferred D. indica to G. wilfordii, and the two backcrosses to A. viridicyanea consumed only a very small percentage of D. indica. Adult females of F₂ showed no significant preference, whereas males of F₂ showed slight preference for G. wilfordii over D. indica. 3. Both the mean feeding preference and the segregation pattern of beetles indicate that the feeding preference of A. viridicyanea and A. fragariae for G. wilfordii and D. indica, respectively, is mainly controlled by a major dominant autosomal gene (or several genes). 4. The variance between feeding preference and oviposition preference of female F₂ indicate that the two behaviour traits of Altica species are controlled by different gene(s).     

Effects of relative humidity on cocoon formation and survival in the braconid wasp Cotesia glomerata

Abstract The effects of relative humidity (RH) on cocoon formation and survival in the braconid parasitoid wasp Cotesia glomerata (L.) (Hymenoptera: Braconidae) are investigated under various humidity conditions (50, 75, 90, 95 and 100% RH) at 20 °C and under an LD 16 : 8 h photoperiod. The mortality rate at the time of egression from hosts under 100% RH is significantly higher than for other RHs. Cocoon clusters formed at 100% RH spread significantly more than those formed at 50, 75, or 90% RH. Developmental periods differ significantly among RHs under which wasps developed. The mean period from the egression from hosts to adult emergence is 8.7 days when developed at 50–95% RHs, and 8.0 days at 100% RH. The emergence rates of C. glomerata that are maintained under the same humidity conditions after egression from hosts are not significantly different among RHs. However, emergence rates from cocoons that are transferred from 100% RH to 50 and 75% RH are < 70%, although the rates are > 90% in most cases. Some wasps do not emerge from cocoons: more than 60% die after adult eclosion at all RHs; the relative frequency of adult deaths is approximately 90% at 50% RH. Relative humidity influences the cluster and cocoon status strongly: both good clusters and cocoons are formed at low RHs. Emergence rates from cocoons of different ranks are significantly different: the rates of low‐rank cocoons are low at low RHs. The survival of C. glomerata is affected strongly by RH through cocoon formation.     

Small Subunit rRNA Phylogenies Show that the Class Nassophorea is Not Monophyletic (Phylum Ciliophora)

ABSTRACT. The hypostome ciliates have been generally classified into two classes, Phyllopharyngea and Nassophorea. The status of Nassophorea and its relationship with Phyllopharyngea is one of the most controversial issues in ciliate systematics. Here we focus on the phylogenetic interrelationships of Nassophorea and Phyllopharyngea based on small subunit ribosomal RNA gene sequences. The three nassophorean subgroups, synhymeniids, microthoracids, and nassulids, each emerged as monophyletic, with synhymeniids as a sister group of Phyllopharyngea, and microthoracids as a sister of the synhymeniids+Phyllopharyngea clade in all phylogenies. The exact placement of the nassulids, however, remains uncertain. Following a detailed analysis of phenotypic characters, we hypothesize that: (1) the Phyllopharyngea could have evolved from synhymeniids, with the further development of their subkinetal microtubules as one of the major events; and (2) the development of monokinetid structures, as well as the reduction and specialization of the cyrtos and cortex, might have occurred during the diversifications of the microthoracids, synhymeniids, and Phyllopharyngea from a common ancestor. Expanding the class Phyllopharyngea to include the synhymeniids as a subclass, and designating a new subclass Subkinetalia n. subcl. for the group comprising cyrtophorians, chonotrichians, rhynchodians, and suctorians, are proposed.     

Twelve polymorphic microsatellite loci for the South China tiger Panthera tigris amoyensis

Twelve microsatellite loci were found from genomic DNA‐enriched libraries of the South China tiger (Panthera tigris amoyensis). The number of observed alleles for each locus in 53 individuals ranged from five to 14; the expected and observed heterozygosity was 0.480 to 0.883 and 0.333 to 0.956, respectively; and the mean polymorphic information content (PIC) was 0.729. These markers would be considered a useful tool for the study of genetic variation in South China tiger in the future.     

The mitochondrial genome of the quiet-calling katydids, <Emphasis Type="Italic">Xizicus fascipes</Emphasis> (Orthoptera: Tettigoniidae: Meconematinae)

To help determine whether the typical arthropod arrangement was a synapomorphy for the whole Tettigoniidae, we sequenced the mitochondrial genome (mitogenome) of the quiet-calling katydids, Xizicus fascipes (Orthoptera: Tettigoniidae: Meconematinae). The 16,166-bp nucleotide sequences of X. fascipes mitogenome contains the typical gene content, gene order, base composition, and codon usage found in arthropod mitogenomes. As a whole, the X. fascipes mitogenome contains a lower A+T content (70.2%) found in the complete orthopteran mitogenomes determined to date. All protein-coding genes started with a typical ATN codon. Ten of the 13 protein-coding genes have a complete termination codon, but the remaining three genes (COIII, ND5 and ND4) terminate with incomplete T. All tRNAs have the typical clover-leaf structure of mitogenome tRNA, except for tRNA(Ser(AGN)), in which lengthened anticodon stem (9 bp) with a bulged nuleotide in the middle, an unusual T-stem (6 bp in constrast to the normal 5 bp), a mini DHU arm (2 bp) and no connector nucleotides. In the A+T-rich region, two (TA)n conserved blocks that were previously described in Ensifera and two 150-bp tandem repeats plus a partial copy of the composed at 61 bp of the beginning were present. Phylogenetic analysis found: i) the monophyly of Conocephalinae was interrupted by Elimaea cheni from Phaneropterinae; and ii) Meconematinae was the most basal group among these five subfamilies.