Wolbachia affects reproduction in the spider mite Tetranychus truncatus (Acari: Tetranychidae) by regulating chorion protein S38-like and Rop

Wolbachia-induced reproductive regulation in hosts has been used to control pest populations, but little is known about the molecular mechanism underlying Wolbachia regulation of host genes. Here, reproductive regulation by Wolbachia in the spider mite Tetranychus truncatus was studied at the molecular level. Infection with Wolbachia resulted in decreasing oviposition and cytoplasmic incompatibility in T. truncatus. Further RNA-seq revealed genes regulated by Wolbachia in T. truncatus. Real-time quantitative polymerase chain reaction (qPCR) showed that genes, including chorion protein S38-like and Rop were down-regulated by Wolbachia. RNA interference (RNAi) of chorion protein S38-like and Rop in Wolbachia-uninfected T. truncatus decreased oviposition, which was consistent with Wolbachia-induced oviposition decrease. Interestingly, suppressing Rop in Wolbachia-infected T. truncatus led to increased Wolbachia titres in eggs; however, this did not occur after RNAi of chorion protein S38-like. This is the first study to show that chorion protein S38-like and Rop facilitate Wolbachia-mediated changes in T. truncatus fertility. In addition, RNAi of Rop turned the body colour of Wolbachia-uninfected T. truncatus black, which indicates that the role of Rop is not limited to the reproductive regulation of T. truncatus.

Evolutionary divergence of mitochondrial genomes in two Tetranychus species distributed across different climates

There is increasing evidence that mitochondrial genomes (mitogenomes) can be under selection, whereas the selective regimes shaping mitogenome evolution remain largely unclear. To test for mitogenome evolution in relation to the climate adaptation, we explored mtDNA variation in two spider mite (Tetranychus) species that distribute across different climates. We sequenced 26 complete mitogenomes of Tetranychus truncates, which occurs in both warm and cold regions, and nine complete mitogenomes of Tetranychus pueraricola, which is restricted to warm regions. Patterns of evolution in the two species' mitogenomes were compared through a series of d_N /d_S methods and physicochemical profiles of amino acid replacements. We found that: (1) the mitogenomes of both species were under widespread purifying selection; (2) elevated directional adaptive selection was observed in the T. truncatus mitogenome, perhaps linked to the cold climates adaptation of T. truncatus; and (3) the strength of selection varied across genes, and diversifying positive selection detected on ND4 and ATP6 pointed to their crucial roles during adaptation to different climatic conditions. This study gained insight into the mitogenome evolution in relation to the climate adaptation.

Geography has a greater effect than Wolbachia infection on population genetic structure in the spider mite, Tetranychus pueraricola

Wolbachia is an intracellular symbiotic bacterium that infects various spider mite species and is associated with alterations in host reproduction, which indicates the potential role in mite evolution. However, studies of Wolbachia infections in the spider mite Tetranychus pueraricola, a major agricultural pest, are limited. Here, we used multilocus sequence typing to determine Wolbachia infection status and examined the relationship between Wolbachia infection status and mitochondrial diversity in T. pueraricola from 12 populations in China. The prevalence of Wolbachia ranged from 2.8 to 50%, and three strains (wTpue1, wTpue2, and wTpue3) were identified. We also found double infections (wTpue1 + wTpue3) within the same individuals. Furthermore, the wTpue1 strain caused weak cytoplasmic incompatibility (CI) (egg hatchability ~55%), whereas another widespread strain, wTpue3, did not induce CI. There was no reduction in mitochondrial DNA (mtDNA) or nuclear DNA diversity among infected individuals, and mtDNA haplotypes did not correspond to specific Wolbachia strains. Phylogenetic analysis and analysis of molecular variance revealed that the distribution of mtDNA and nuclear DNA haplotypes were significantly associated with geography. These findings indicate that Wolbachia infection in T. pueraricola is complex, but T. pueraricola genetic differentiation likely resulted from substantial geographic isolation.

Phase II study of patients with metastatic nonsmall cell carcinoma of the lung treated with paclitaxel by 3-hour infusion

BACKGROUND

Single-agent chemotherapy produces partial responses in the range of 7-27% in patients with Stage IV nonsmall cell lung carcinoma (NSCLC). Cisplatin-based combination regimens have achieved higher response rates but with significant toxicity. Two prior studies employing 24-hour infusions of paclitaxel showed responses of 21% and 24%. The purpose of this Phase II study was to determine the effects of paclitaxel administered by short duration infusions on response rate, toxicity, and quality of life (QOL) in patients with NSCLC.

METHODS

Twenty patients with histologically proven Stage IV NSCLC were enrolled in this study. All were treated on an outpatient basis with standard premedication followed by paclitaxel 200 mg/m2 infused intravenously over 3 hours. Treatments were repeated every 21 days for a maximum of 6 cycles.

RESULTS

The objective response rate was 6/19 (32%; 95% confidence interval, 13-57%). The median duration of response was 6.0 months (range, 2-13 months). The median survival of the entire group was 6.0 months (range, 2-24+ months), and the 1-year survival rate was 22%. Toxicity was mild, with only one hospitalization required for treatment of catheter-related thrombosis. Nonresponding patients were found to have worsening Functional Assessment of Cancer Therapy (FACT)-G and FACT-L scores. Because this was a small clinical study, it did not demonstrate consistent improvement in FACT-G or FACT-L in responding patients.

CONCLUSIONS

Paclitaxel given as a 3-hour infusion is a well-tolerated, active single agent in the treatment of Stage IV NSCLC, worthy of further study. Baseline QOL scores predicted those more likely to respond to treatment, but changes in QOL status did not correlate well with objective response status.

Anti-arrhythmic effects of captopril on coronary occlusion and reperfusion periods in pigs

Anti-arrhythmic effects of captopril (Cap) were studied in the anesthetized pigs using a reversible balloon catheter. Results showed that Cap did not exert any influence on the weight percentage of ischemic area to the whole left ventricle, on the levels of serum creatine kinase (CK) and creatine kinase isozyme (CK-MB), nor on the incidence and duration of transient and persistent tachycardia, but reduced the incidence of ventricular fibrillation (2/12, 1/12 in high-dose group pigs treated with Cap 6 mg.kg-1 in the first 10 min, 25 micrograms.kg-1.min-1 in the later 90 min and 12/21, 11/21 in control group treated with normal saline through the occlusion and reperfusion periods, respectively, P < 0.05). It was suggested that Cap did not exhibit direct (or non-specific, if any) effects on anti-arrhythmias.

Electrophysiological and pathological observations on experimental coxsackie B-3 viral myocarditis in mice

Electrophysiological action of right ventricular myocardium examined by standard intracellular microelectrode technique and real-time microcomputer data processor system and histological and ultrastructural changes of myocardium in BALB/c mice infected with coxsackie B-3 virus from 3 days to 9 months were observed. It was found that electrophysiologic parameters of action potential changed very quickly at the early stage (3 days to 1 month) of the disease. Those abnormalities became most apparent by the 5-30th day, and 7 patterns of abnormal action potential occurred frequently within the same period. These changes were basically parallel to the myocardial lesions. At the late stage (3-9 months) the electrophysiological parameters were nearly normal, while the myocardial lesions decreased gradually. However, the abnormal patterns of action potential were still detected, even though they were improved gradually. The results suggest that myocardial damages caused by viral infection may lead to changes of cardiac electric action, which may be one of the factors in arrhythmias in the episode of viral myocarditis.

Effect of verapamil on acute coxsackievirus B3 murine myocarditis

The effect of verapamil (Ver) on CVB3 murine myocarditis was investigated. It was found that Ver could aggravate the myocardial inflammation, increase the viral replication in myocardium, and raise mortality in mice with viral myocarditis when the drug was injected within the first 6 days after the CVB3 inoculation.

[Influence of dexamethasone on electrical activities in cultured rat beating myocardial cells infected with Coxsackie B-2 virus]

The effects of dexamethasone (Dex) on electrical activities in cultured rat beating myocardial cells infected with 100 TCID-50 Coxsackie B-2 virus (CB2V) was evaluated by conventional intracellular microelectrode technique. The frequency began to increase, the beating % decreased, and multiform arrhythmias were shown in the infected group 24 h post-challenge. Meanwhile, the cytopathic effect (CPE) appeared rapidly from 1+ to 3+. In the infected and Dex-treated group, the beating % was higher and the arrhythmias and CPE were less than in the infected group at the same intervals. The numbers of non-beating cells increased parallel to the incubation time in the infected group. Decreases of maximal diastolic potential (MDP), maximal upstroke rate (Vmax), overshoot (OS) and action potential amplitude (APA), and abbreviation of action potential duration (APD50 and APD100) in infected and Dex-treated group were less than those in control group during 24-96 h post-challenge. Premature beats, tachycardia, bradycardia and fibrillation occurred in the early stages after infection. It is surmised that steroids can probably save the lives of patients with severe myocarditis if Dex was supplemented.

Effect of Astragulas membranaceus on natural killer cell activity and induction of alpha- and gamma-interferon in patients with Coxsackie B viral myocarditis

The patients suffering from Coxsackie B viral myocarditis with depressed natural killer (NK) activity were treated with Astragulas membranaceus (AM) intramuscularly for 3-4 months. After the treatment, the NK activity was increased significantly from 11.5 +/- 11.9% before therapy to 44.9 +/- 15.0%. Another 6 patients of Coxsackie B viral myocarditis with depressed NK activity were treated with conventional therapy. The NK activity remained unchanged in 12.9 +/- 6%. The general condition and symptoms improved in all patients with AM therapy, while the titers of neutralizing antibody remained at the same level. Two days after AM treatment, the mean titers of alpha- and gamma-interferon (IFN) markedly increased in comparison with those before therapy and 3 weeks after AM therapy in 16 patients with Coxsackie B viral myocarditis, with left ventricular ejection fraction (LVEF) less than 65% and/or weak ventricular wall motion assayed by radionuclide angiocardiography. Whereas, in 12 patients treated with conventional therapy, there was no statistical difference among the results before and 2 days and 3 weeks after treatment. The results indicate that AM could partly regulate the lost of control of cellular immunity in patients with viral myocarditis.

Effect of astragalus membranaceus on electric activities of cultured rat beating heart cells infected with Coxsackie B-2 virus

Astragalus membranaceus (AM) which has a protective effect on rat beating heart cells infected experimentally with Coxsackie B-2 virus was evaluated on the basis of changes in morphologic and electric activity of the cells. Rhythm, beating frequency, beating percentage, cardiac cellular damage and cytopathic effects (CPE) were monitored every 24 h after challenge; electric activities parameters were measured by conventional intracellular microelectrode technique. Significant protective effects were demonstrated when AM was given in the early period of infection. The results suggest that AM should be valuable in preventing and treating acute myocarditis caused by Coxsackie B virus.

Treatment of experimental Coxsackie B-3 viral myocarditis with Astragalus membranaceus in mice

A murine model system for observing the effect of Astragalus Membranaceus (AM) on experimental myocarditis caused by Coxsackie B-3 virus (CB3V) was developed in 4-week-old male BALB/C mice. Gross, histopathologic and ultrastructural examinations of the infected-AM treated group showed that the severity and involved area of the myocardial lesions became milder and smaller than those in the infected-NS treated mice. The total lesion area, and the total lesion area/total myocardial area examined (%) and virus titer in the former group were also smaller and lower than those in the latter group. The results suggest that AM is effective in the inhibition of Coxsackie B virus propagation and protection of myocardium in mouse myocarditis.

[Effect of dexamethasone on Coxsackie B-2 virus-infected rat beating heart cells in culture]

The effects of dexamethasone (Dex) on cultured rat beating heart cells infected with 100 TCID-50 Coxsackie virus B-2 (CB2V) were observed. The beating % began to decrease in the infected group 2 or 3 d post-challenge. Meanwhile, the cytopathic effect (CPE) appeared rapidly from 1+ to 3+. In the infected and Dex-treated group 1 h after inoculation, the beating % and CPE in the whole flask were significantly higher and less, respectively, than that in the group infected (P less than 0.05) at the same intervals. At 5 d after challenge, the beating % in the whole flask was significantly higher than that in the infected group. The cardiac enzyme-aspartate aminotransferase (AST) in the infected group was higher than that in the infected and Dex-treated group (P less than 0.01) through 3-5 d post-challenge. Moreover, the AST levels in these 2 groups were also higher than that in the uninfected group, Dex control group at the same intervals (P less than 0.01). Ultrastructural findings were parallel to the results of CPE through 1-5 d post-challenge in these 4 groups. It is suggested that the protective effect of Dex on cultured beating heart cells infected with CB2V occurred in the early stages after infection. It is surmised that steroids can probably save the lives of patients with severe myocarditis if the conventional therapy for protecting the myocardium and improving immunity were administered together.

[Cytotoxic effects of changrolin, lidocaine and amiodarone on ultrastructure of cultured rat beating cardiac myocytes]

Ultrastructural and morphological alterations of cultured rat beating cardiac myocytes treated with changrolin (CRL), lidocaine (Lid), and amiodarone (Ami) were studied. After the cultures were treated with CRL 100 micrograms/ml for 24 h, the beating of the myocytes stopped, the configuration and fine structure were destroyed, while the nuclei showed pyknotic deformation and reduced in size. The membrane and structures of mitochondria were disrupted and myofibrils fragmented and disrupted. In addition, a lot of vacuoles with characteristic dense particles were found in the cytoplasm. Similar alterations were seen when Lid 1000 micrograms/ml and Ami 50 micrograms/ml were added to the cultures. Normal beating networks of myocytes were examined under inverted microscopy after the cultured cells were treated with CRL 25 micrograms/ml, Lid 250 micrograms/ml or Ami 6.25 micrograms/ml. The ultrastructure of some regions of the myocytes showed very slight damage. The results indicated that the dosage of CRL and Lid generally used in anti-arrhythmic therapy basically exerted no harm to myocytes. However, caution should be taken when Ami was given intravenously, since its effective serum concentration was close to the dosage which could cause slight damage to the ultrastructure of cultured cells.