Influences of two coexisting endosymbionts,CI‐inducing Wolbachia and male‐killing Spiroplasma,on the performance of their host Laodelphax striatellus (Hemiptera: Delphacidae)

The small brown planthopper Laodelphax striatellus (Hemiptera: Delphacidae) is reported to have the endosymbiont Wolbachia, which shows a strong cytoplasmic incompatibility (CI) between infected males and uninfected females. In the 2000s, female‐biased L. striatellus populations were found in Taiwan, and this sex ratio distortion was the result of male‐killing induced by the infection of another endosymbiont, Spiroplasma. Spiroplasma infection is considered to negatively affect both L. striatellus and Wolbachia because the male‐killing halves the offspring of L. striatellus and hinders the spread of Wolbachia infection via CI. Spiroplasma could have traits that increase the fitness of infected L. striatellus and/or coexisting organisms because the coinfection rates of Wolbachia and Spiroplasma were rather high in some areas. In this study, we investigated the influences of the infection of these two endosymbionts on the development, reproduction, and insecticide resistance of L. striatellus in the laboratory. Our results show that the single‐infection state of Spiroplasma had a negative influence on the fertility of L. striatellus, while the double‐infection state had no significant influence. At late nymphal and adult stages, the abundance of Spiroplasma was lower in the double‐infection state than in the single‐infection state. In the double‐infection state, the reduction of Spiroplasma density may be caused by competition between the two endosymbionts, and the negative influence of Spiroplasma on the fertility of host may be relieved. The resistance of L. striatellus to four insecticides was compared among different infection states of endosymbionts, but Spiroplasma infection did not contribute to increase insecticide resistance. Because positive influences of Spiroplasma infection were not found in terms of the development, reproduction, and insecticide resistance of L. striatellus, other factors improving the fitness of Spiroplasma‐infected L. striatellus may be related to the high frequency of double infection in some L. striatellus populations.     

Identification of cis-localization elements of the maize 10-kDa δ-zein and their use in targeting RNAs to specific cortical endoplasmic reticulum subdomains

The RNAs for the storage proteins of rice ( Oryza sativa ), prolamines and glutelins, which are stored as inclusions in the lumen of the endoplasmic reticulum (ER) and storage vacuoles, respectively, are targeted by specific cis -localization elements to distinct subdomains of the cortical ER. Glutelin RNA has one or more cis -localization elements (zip codes) at the 3' end of the RNA, whereas prolamine has two cis -elements; one located in the 5' end of the coding sequence and a second residing in the 3'-untranslated region (UTR). We had earlier demonstrated that the RNAs for the maize zeins ('prolamine' class) are localized to the spherical protein body ER (PB-ER) in developing maize endosperm. As the PB-ER localization of the 10-kDa δ-zein RNA is maintained in developing rice seeds, we determined the number and proximate location of their cis -localization elements by expressing GFP fusions containing various zein RNA sequences in transgenic rice and analyzing their spatial distribution on the cortical ER by in situ RT-PCR and confocal microscopy. Four putative cis -localization elements were identified; three in the coding sequences and one in the 3'-UTR. Two of these zip codes are required for restricted localization to the PB-ER. Using RNA targeting determinants we show, by mis-targeting the storage protein RNAs from their normal destination on the cortical ER, that the coded proteins are redirected from their normal site of deposition. Targeting of RNA to distinct cortical ER subdomains may be the underlying basis for the variable use of the ER lumen or storage vacuole as the final storage deposition site of storage proteins among flowering plant species.     

HSP60 interacts with YB-1 and affects its polysome association and subcellular localization

YB-1 is a DNA/RNA-binding protein which, in the cytoplasm, associates with polysomes and regulates translation. However, YB-1 has a novel nuclear localization signal, and its nuclear accumulation is correlated with cancer induction. Here we designated the amino-acid sequence as YB-NLS and demonstrated that YB-NLS is necessary for the nuclear translocation of overexpressed YB-1 in NG108-15 cells. In addition, we found that a heat shock protein, HSP60, binds to YB-NLS in the cytoplasm. Interestingly, when HSP60 expression was repressed, an increase of polysome-associated YB-1 was observed in heavy-sedimenting fractions on a sucrose gradient. Overexpression of HSP60 resulted in a decrease of YB-1 in the heavy-sedimenting fractions and suppression of YB-NLS activity. Furthermore, the NLS-deleted YB-1 was apparently associated with the heavy-sedimenting polysomes. These results suggest that HSP60 interacts with YB-1 at the YB-NLS region and acts as a regulator of polysome association and the subcellular distribution of YB-1.     

Identification of Neuronal Nuclei (NeuN) as Fox-3, a New Member of the Fox-1 Gene Family of Splicing Factors

NeuN (neuronal nuclei) is a neuron-specific nuclear protein which is identified by immunoreactivity with a monoclonal antibody, anti-NeuN. Anti-NeuN has been used widely as a reliable tool to detect most postmitotic neuronal cell types in neuroscience, developmental biology, and stem cell research fields as well as diagnostic histopathology. To date, however, the identity of its antigen, NeuN itself, has been unknown. Here, we identify NeuN as the Fox-3 gene product by providing the following evidence: 1) Mass spectrometry analysis of anti-NeuN immunoreactive protein yields the Fox-3 amino acid sequence. 2) Recombinant Fox-3 is recognized by anti-NeuN. 3) Short hairpin RNAs targeting Fox-3 mRNA down-regulate NeuN expression. 4) Fox-3 expression is restricted to neural tissues. 5) Anti-Fox-3 immunostaining and anti-NeuN immunostaining overlap completely in neuronal nuclei. We also show that a protein cross-reactive with anti-NeuN is the synaptic vesicle protein, synapsin I. Anti-NeuN recognizes synapsin I in immunoblots with one order of magnitude lower affinity than Fox-3, and does not recognize synapsin I using immunohistology. Fox-3 (also called hexaribonucleotide-binding protein 3 and D11Bwg0517e) contains an RNA recognition motif and is classified as a member of the Fox-1 gene family that binds specifically to an RNA element, UGCAUG. We demonstrate that Fox-3 functions as a splicing regulator using neural cell-specific alternative splicing of the non-muscle myosin heavy chain II-B pre-mRNA as a model. Identification of NeuN as Fox-3 clarifies an important element of neurobiology research.     

First report of the invasive crop pest Stenocranus pacificus (Hemiptera: Delphacidae) in temperate Asia

Numerous delphacid planthopper species are major pests of economically important and widely cultivated crops (i.e. rice, corn, and sugarcane). These insects have the potential to become serious crop pests in areas where they have either naturally migrated or been newly introduced. The white-bellied planthopper, Stenocranus pacificus Kirkaldy, 1907, originally known from tropical South Pacific islands, appeared in tropical and subtropical Asia in the early years of the 21st century. Since then, S. pacificus has become a serious pest of corn in some Southeast Asian countries, although it also feeds on rice, sugarcane, sorghum, and other grasses. Here, we report the presence of S. pacificus in mainland Japan, representing the first record of this species in temperate Asia. Seven male and 17 female adult individuals collected in Kumamoto Prefecture in 2019 and 2020 were identified as S. pacificus based on their morphological characteristics and mitochondrial COI sequences. In addition, molecular phylogenetic analysis showed that S. pacificus formed a distinct clade from other Stenocranus species, indicating uncertainty in its generic assignment. Although crop damage by S. pacificus has not yet been reported from temperate regions, given its wide range of plant hosts and the potential for future range expansions, damaged crops in Asia, including in temperate regions, should be monitored for the presence of this species.     

Infection of Adult Thymus with Murine Retrovirus Induces Virus-Specific Central Tolerance That Prevents Functional Memory CD8+ T Cell Differentiation

In chronic viral infections, persistent antigen presentation causes progressive exhaustion of virus-specific CD8⁺ T cells. It has become clear, however, that virus-specific naïve CD8⁺ T cells newly generated from the thymus can be primed with persisting antigens. In the setting of low antigen density and resolved inflammation, newly primed CD8⁺ T cells are preferentially recruited into the functional memory pool. Thus, continual recruitment of naïve CD8⁺ T cells from the thymus is important for preserving the population of functional memory CD8⁺ T cells in chronically infected animals. Friend virus (FV) is the pathogenic murine retrovirus that establishes chronic infection in adult mice, which is bolstered by the profound exhaustion of virus-specific CD8⁺ T cells induced during the early phase of infection. Here we show an additional evasion strategy in which FV disseminates efficiently into the thymus, ultimately leading to clonal deletion of thymocytes that are reactive to FV antigens. Owing to the resultant lack of virus-specific recent thymic emigrants, along with the above exhaustion of antigen-experienced peripheral CD8⁺ T cells, mice chronically infected with FV fail to establish a functional virus-specific CD8⁺ T cell pool, and are highly susceptible to challenge with tumor cells expressing FV-encoded antigen. However, FV-specific naïve CD8⁺ T cells generated in uninfected mice can be primed and differentiate into functional memory CD8⁺ T cells upon their transfer into chronically infected animals. These findings indicate that virus-induced central tolerance that develops during the chronic phase of infection accelerates the accumulation of dysfunctional memory CD8⁺ T cells.     

Pregnancy,delivery, and breastfeeding after total gastrectomy for gastric cancer: a case report

Background

The reports of pregnancy after total gastrectomy for gastric cancer are rare.

Case presentation

We report a case of a 35-year-old woman, gravida 0, para 0, who became pregnant and delivered a baby 2?years and 6?months after laparoscopic-assisted total gastrectomy for early gastric cancer. Postoperatively, she showed a good progress during the follow-up and was continuously taking oral iron supplement and administered with methylcobalamin intramuscular injection. Two years after gastrectomy, she became pregnant. During the pregnancy, she kept taking iron and vitamin B₁₂ supplementation and had a good course of pregnancy and a normal delivery. However, 2?months after the delivery, liver dysfunction was detected via blood examination. The patient switched from exclusive breastfeeding to combined feeding with formula, and her laboratory results returned to normal. During 10?years of follow-up after the delivery, the patient was in good condition without any recurrence and nutritional deficiencies, and her child had thrived.

Conclusions

Careful monitoring and management of iron and vitamin deficiencies are essential during pregnancy and the lactation periods for patients who previously underwent total gastrectomy. During the lactation period, a combination of formula and breastfeeding provides maternal and fetal nutritional support.