A newly recorded Rickettsia of the Torix group is a recent intruder and an endosymbiont in the whitefly Bemisia tabaci.

The bacterium Rickettsia is found widely in phytophagous insects and often exerts profound effects on the phenotype and fitness of its hosts. Here, we decrypt a new, independent, phylogenetically ancient Torix Rickettsia endosymbiont found constantly in a laboratory line of an economically important insect Asia II 7, a putative species of the Bemisia tabaci whitefly complex (Hemiptera: Aleyrodidae), and occasionally in field whitefly populations. This new Rickettsia distributes throughout the body of its whitefly host. Genetically, compared to Rickettsia_bellii_MEAM1 found earlier in whiteflies, the new Rickettsia species has more gene families and pathways, which may be important factors in shaping specific symbiotic relationships. We propose the name 'Candidatus Rickettsia_Torix_Bemisia_tabaci (RiTBt)' for this new endosymbiont associated with whiteflies. Comparative genomic analyses indicate that RiTBi may be a relatively recent intruder in whiteflies given its low abundance in the field and relatively larger genome compared to Rickettsia_bellii_MEAM1.

The inherited bacterial symbiont Hamiltonella influences the sex ratio of an insect host.

In many intracellular symbioses, the microbial symbionts provide nutrients advantageous to the host. However, the function of Hamiltonella defensa, a symbiotic bacterium localized in specialized host cells (bacteriocytes) of a whitefly Bemisia tabaci, is uncertain. We eliminate this bacterium from its whitefly host by two alternative methods: heat treatment and antibiotics. The sex ratio of the host progeny and subsequent generations of Hamiltonella-free females was skewed from 1 : 1 (male : female) to an excess of males, often exceeding a ratio of 20 : 1. B. tabaci is haplodiploid, with diploid females derived from fertilized eggs and haploid males from unfertilized eggs. The Hamiltonella status of the insect did not affect copulation frequency or sperm reserve in the spermathecae, indicating that the male-biased sex ratio is unlikely due to the limitation of sperm but likely to be associated with events subsequent to sperm transfer to the female insects, such as failure in fertilization. The host reproductive response to Hamiltonella elimination is consistent with two alternative processes: adaptive shift in sex allocation by females and a constitutive compensatory response of the insect to Hamiltonella-mediated manipulation. Our findings suggest that a bacteriocyte symbiont influences the reproductive output of female progeny in a haplodiploid insect.

Cellular and molecular remodelling of a host cell for vertical transmission of bacterial symbionts.

Various insects require intracellular bacteria that are restricted to specialized cells (bacteriocytes) and are transmitted vertically via the female ovary, but the transmission mechanisms are obscure. We hypothesized that, in the whitefly Bemisia tabaci, where intact bacteriocytes (and not isolated bacteria) are transferred to oocytes, the transmission mechanism would be evident as cellular and molecular differences between the nymph (pre-adult) and adult bacteriocytes. We demonstrate dramatic remodelling of bacteriocytes at the developmental transition from nymph to adulthood. This transition involves the loss of cell-cell adhesion, high division rates to constant cell size and onset of cell mobility, enabling the bacteriocytes to crawl to the ovaries. These changes are accompanied by cytoskeleton reorganization and changes in gene expression: genes functioning in cell-cell adhesion display reduced expression and genes involved in cell division, cell motility and endocytosis/exocytosis have elevated expression in adult bacteriocytes, relative to nymph bacteriocytes. This study demonstrates, for the first time, how developmentally orchestrated remodelling of gene expression and correlated changes in cell behaviour underpin the capacity of bacteriocytes to mediate the vertical transmission and persistence of the symbiotic bacteria on which the insect host depends.

Differential responses of the whitefly Bemisia tabaci symbionts to unfavorable low and high temperatures.

The whitefly Bemisia tabaci complex contains many cryptic species, of which the Middle East-Asia Minor 1 (MEAM1) and Mediterranean (MED) are notorious invasive pests. In our field-collected whitefly samples, MEAM1 harbors an obligate primary symbiont "Candidatus Portiera aleyrodidarum" and two secondary symbionts, "Candidatus Hamiltonella defensa" and Rickettsia sp., whereas MED has only "Ca. Portiera aleyrodidarum" and "Ca. Hamiltonella defensa." Both "Ca. Portiera aleyrodidarum" and "Ca. Hamiltonella defensa" are intracellular endosymbionts residing in the bacteriomes, whereas Rickettsia sp. has a scattered distribution throughout the host body cavity. We examined responses of these symbionts to adverse temperatures as well as survival of the host insects. After cold treatment at 5 or 10 °C or heat treatment at 35 or 40 °C for 24 h, respectively, the infection rates of all symbionts were not significantly decreased based on diagnosis PCR. However, quantitative PCR assays indicated significant reduction of "Ca. Hamiltonella defensa" at 40 °C, and the reduction became greater as the duration increased. Compared with "Ca. Hamiltonella defensa," "Ca. Portiera aleyrodidarum" was initially less affected in the first day but then showed more rapid reduction at days 3-5. The density of Rickettsia sp. fluctuated but was not reduced significantly at 40 °C. Meanwhile, the mortality rates of the host whiteflies elevated rapidly as the duration of exposure to heat treatment increased. The differential responses of various symbionts to adverse temperatures imply complex interactions among the symbionts inside the same host insect and highlight the importance of taking the whole bacterial community into account in studies of symbioses.

The plant-sucking insect selects assembly of the gut microbiota from environment to enhance host reproduction.

Plant-sucking insects have intricate associations with a diverse array of microorganisms to facilitate their adaptation to specific ecological niches. The midgut of phytophagous true bugs is generally structured into four distinct compartments to accommodate their microbiota. Nevertheless, there is limited understanding regarding the origins of these gut microbiomes, the mechanisms behind microbial community assembly, and the interactions between gut microbiomes and their insect hosts. In this study, we conducted a comprehensive survey of microbial communities within the midgut compartments of a bean bug Riptortus pedestris, soybean plant, and bulk soil across 12 distinct geographical fields in China, utilizing high-throughput sequencing of the 16 S rRNA gene. Our findings illuminated that gut microbiota of the plant-sucking insects predominantly originated from the surrounding soil environment, and plants also play a subordinate role in mediating microbial acquisition for the insects. Furthermore, our investigation suggested that the composition of the insect gut microbiome was probably shaped by host selection and/or microbe-microbe interactions at the gut compartment level, with marginal influence from soil and geographical factors. Additionally, we had unveiled a noteworthy dynamic in the acquisition of core bacterial taxa, particularly Burkholderia, which were initially sourced from the environment and subsequently enriched within the insect midgut compartments. This bacterial enrichment played a significant role in enhancing insect host reproduction. These findings contribute to our evolving understanding of microbiomes within the insect-plant-soil ecosystem, shedding additional light on the intricate interactions between insects and their microbiomes that underpin the ecological significance of microbial partnerships in host adaptation.

A Novel Nitrogen-Fixing Bacterium Raoultella electrica Isolated from the Midgut of the Leafhopper Recilia dorsalis.

Nitrogen is a crucial element for the growth and development of insects, but herbivorous insects often suffer from nitrogen nutrition deficiencies in their diets. Some symbiotic microorganisms can provide insect hosts with nitrogen nutrition through nitrogen fixation. Extensive research has clearly demonstrated the process of nitrogen fixation by symbiotic microorganisms in termites, while evidence supporting the occurrence and significance of nitrogen fixation in the diets of the Hemiptera is less conclusive. In this study, we isolated a strain of R. electrica from the digestive tract of a leafhopper, R. dorsalis, and found that it had nitrogen-fixing capabilities. Fluorescence in situ hybridization results showed that it was located in the gut of the leafhopper. Genome sequencing revealed that R. electrica possessed all the genes required for nitrogen fixation. We further evaluated the growth rate of R. electrica in nitrogen-containing and nitrogen-free media and measured its nitrogenase activity through an acetylene reduction assay. The findings of these studies could shed light on how gut microbes contribute to our understanding of nitrogen fixation.

Diversity and Dynamics of Bacterial Communities in the Digestive and Excretory Systems across the Life Cycle of Leafhopper, Recilia dorsalis.

Recilia dorsalis is a notorious rice pest that harbors numerous symbiotic microorganisms. However, the structure and dynamics of bacterial communities in various tissues of R. dorsalis throughout its life cycle remain unclear. In this study, we used high-throughput sequencing technology to analyze the bacterial communities in the digestive, excretory, and reproductive systems of R. dorsalis at different developmental stages. The results showed that the initial microbiota in R. dorsalis mostly originated from vertical transmission via the ovaries. After the second-instar nymphs, the diversity of bacterial communities in the salivary gland and Malpighian tubules gradually decreased, while the midgut remained stable. Principal coordinate analysis revealed that the structure of bacterial communities in R. dorsalis was primarily influenced by the developmental stage, with minimal variation in bacterial species among different tissues but significant variation in bacterial abundance. Tistrella was the most abundant bacterial genus in most developmental stages, followed by Pantoea. The core bacterial community in R. dorsalis continuously enriched throughout development and contributed primarily to food digestion and nutrient supply. Overall, our study enriches our knowledge of the bacterial community associated with R. dorsalis and provides clues for developing potential biological control technologies against this rice pest.

Distribution, Vertical Transmission, and Cooperative Mechanisms of Obligate Symbiotic Bacteria in the Leafhopper Maiestas dorsalis (Hemiptera, Cicadellidea).

Many insects rely on ancient symbiotic bacterial associations for essential nutrition. Auchenorrhyncha commonly harbor two obligate symbionts: Sulcia (Bacteroidetes) and a proteobacterial partner that supplies essential amino acids lacking in their plant-sap diets. In this study focusing on Maiestas dorsalis, we investigated the distribution and vertical transmission of two obligate symbiotic bacteria, Sulcia and Nasuia, within the leafhopper. Sulcia primarily inhabits the external region of the bacteriome, while Nasuia is restricted to the internal region. Both symbionts progressively infiltrate the ovary through the epithelial plug, ultimately reaching the developing primary oocyte. Furthermore, co-phylogenetic analysis suggests a close correlation between the evolution of Auchenorrhyncha insects and the presence of their obligate symbiotic bacteria. Genomic analysis further unveiled the extreme genome reduction of the obligate symbiotic bacteria, with Sulcia retaining genes involved in basic cellular processes and limited energy synthesis, while Nasuia exhibited further gene loss in replication, transcription, translation, and energy synthesis. However, both symbionts retained the genes for synthesizing the essential amino acids required by the host insect. Our study highlights the coevolutionary dynamics between Sulcia, proteobacterial partners, and their insect hosts, shedding light on the intricate nutritional interactions and evolutionary adaptations in Auchenorrhyncha insects.

Insights into Brochosome Distribution, Synthesis, and Novel Rapid-Release Mechanism in Maiestas dorsalis (Hemiptera: Cicadellidae).

The leafhopper family Cicadellidae, comprising over 22,000 species, exhibits a unique behavior of anointing their bodies with excretions containing brochosomes. Brochosomes are synthesized in the distal segment of the Malpighian tubules and serve various functions, including hydrophobic protection and defense against pathogens and predators. In this study, we investigated the distribution, synthesis, and release mechanisms of brochosomes in the rice pest leafhopper Maiestas dorsalis. Using SEM and TEM, we observed brochosomes' consistent coverage on the integument throughout the insect's life cycle. Moreover, we identified four distinct developmental stages of brochosome synthesis within the distal segment of the Malpighian tubules, originating from the Golgi region. Most importantly, our research revealed a novel and highly efficient release mechanism involving the fusion of brochosome-containing vesicles, leading to a rapid and substantial release of brochosomes into the tubule lumen after molting. These findings shed light on the intricate processes of brochosome synthesis and release in leafhoppers, offering valuable insights into their functional significance and ecological role in these fascinating insects.

Combined Transcriptome and Proteome Analysis of the Protein Composition of the Brochosomes of the Leafhopper Nephotettix cincticeps.

Brochosomes, unique coatings on the integuments of Cicadellidae, are synthesized in specialized glandular sections of Malpighian tubules. However, limited knowledge exists regarding the protein composition of brochosomes. In this study, we conducted transcriptomic and proteomic profiling to characterize the brochosome protein composition in the rice green leafhopper Nephotettix cincticeps. Brochosomes were collected from the forewings of leafhoppers using ultrasonic treatment, allowing for more effective brochosome collection and shaking treatment, resulting in purer brochosomes. Transcriptome sequencing analysis identified 106 genes specifically expressed in the Malpighian tubules; combined with proteomic data, we identified 22 candidate brochosome proteins. These proteins were classified into 12 brochosomins (BSM) and 10 brochosome-associated proteins (BSAP) based on previous research. Conserved motif analysis and functional predictions unveiled unique motifs in each BSM, while BSAP appeared to play a crucial role in BSM folding and pathogen resistance. Comparative analysis of other Hemiptera species demonstrated that all BSM and some BSAP are specific to the Cicadellidae family. Our findings could contribute to understanding the mechanism of brochosome synthesis, its function, and evolutionary genesis.

Roles of Bacterial Symbionts in Transmission of Plant Virus by Hemipteran Vectors.

The majority of plant viruses are transmitted by hemipteran insects. Bacterial symbionts in hemipteran hosts have a significant impact on the host life, physiology and ecology. Recently, the involvement of bacterial symbionts in hemipteran vector-virus and vector-plant interactions has been documented. Thus, the exploitation and manipulation of bacterial symbionts have great potential for plant viral disease control. Herein, we review the studies performed on the impact of symbiotic bacteria on plant virus transmission, including insect-bacterial symbiont associations, the role of these bacterial symbionts in viral acquisition, stability and release during viral circulation in insect bodies, and in viral vertical transmission. Besides, we prospect further studies aimed to understand tripartite interactions of the virus-symbiotic microorganisms-insect vector.

[Nosocomial infection caused by Pseudomonas aeruginosa in intensive care unit].

OBJECTIVE: To investigate the risk factors of nosocomial infection caused by Pseudomonas aeruginosa in intensive care unit (ICU), in order to provide reference for an effective measure of infection control. METHODS: A retrospective study of cases of Pseudomonas aeruginosa infection occurring in ICU was made with multivariable Logistic regression analysis. The clinical data of 1 950 cases admitted from January 2002 to December 2006 were found to have nosocomial infection caused by Pseudomonas aeruginosa were analyzed in order to identify its independent risk factors. RESULTS: Sixty-four out of 1 950 patients were found to suffer from nosocomial infection caused by Pseudomonas aeruginosa, the morbidity rate was 3.3%. At the same time, and in the same department, 37 patients suffering from infection caused by Escherichia coli, served as control group. Univariate analysis showed that the risk factors for nosocomial infection caused by Pseudomonas aeruginosa were the use of corticosteroid, unconsciousness or craniocerebral trauma, abdominal surgery, thorax/abdomen drainage tube, mechanical ventilation, and tracheostomy [the use of corticosteroid: odds ratio (OR)=3.364, 95% confidence interval (95%CI) 1.445-7.830; unconsciousness or craniocerebral trauma: OR=4.026, 95%CI 1.545-10.490; abdominal surgery: OR=0.166, 95%CI 0.068-0.403; thorax/abdomen drainage tube: OR=0.350, 95%CI 0.150-0.818; tracheostomy: OR=4.095, 95%CI 1.638-10.740]. Multivariate analysis showed that the independent risk factors of nosocomial infection caused by Pseudomonas aeruginosa in ICU were: the use of corticosteroid and mechanical ventilation [the use of corticosteroid: OR=3.143, 95%CI 1.115-8.856; mechanical ventilation: OR=3.195, 95%CI 1.607-6.353, P<0.05 and P<0.01]. CONCLUSION: The independent risk factors of nosocomial infection caused by Pseudomonas aeruginosa in ICU are the use of corticosteroid and mechanical ventilation. Measures should be taken to take care of the risk factors in order to prevent nosocomial infection caused by Pseudomonas aeruginosa in ICU.

The Costs and Benefits of Two Secondary Symbionts in a Whitefly Host Shape Their Differential Prevalence in the Field.

Insects commonly harbor maternally inherited intracellular symbionts in nature, and the microbial partners often exert influence on host reproduction and fitness to promote their prevalence. Here, we investigated composition of symbionts and their biological effects in the invasive Bemisia tabaci MED species of a whitefly complex. Our field surveys revealed that populations of the MED whitefly, in addition to the primary symbiont Portiera, mainly contain two secondary symbionts Hamiltonella, which is nearly fixed in the host populations, and Cardinium with infection frequencies ranging from 0 to 86%. We isolated and established Cardinium-positive and Cardinium-free whitefly lines with a similar nuclear genetic background from a field population, and compared performance of the two whitefly lines. The infection of Cardinium incurred significant fitness costs on the MED whitefly, including reduction of fecundity and egg viability as well as delay in development. We then selectively removed Hamiltonella from the Cardinium-free whitefly line and compared performance of two whitefly lines, one harboring both Portiera and Hamiltonella and the other harboring only Portiera. While depletion of Hamiltonella had little or only marginal effects on the fecundity, developmental rate, and offspring survival, the Hamiltonella-free whitefly line produced very few female offspring, often reducing the progeny female ratio from about 50% to less than 1%. Our findings indicate that the varying costs and benefits of the association between these two symbionts and the MED whitefly may play an important role in shaping their differential prevalence in the field.

[Effects of rhubarb and different routes of nutrition support on invasive fungal infection].

OBJECTIVE: To study the effects of rhubarb and the different routes of nutrition support on invasive fungal infection. METHODS: One thousand and ninety patients, who suffered from sepsis subsequent to trauma, shock and infection were enrolled in this study. The patients were randomly divided into two groups, 637 cases in rhubarb preventive treatment group and 453 cases in non-preventive rhubarb treatment group. They were again divided into four subgroups: enteral nutrition support, and no nutrition support group. The incidence of invasive fungal infection was observed in those groups. RESULTS: The incidence of invasive fungal infection in rhubarb preventive treatment group (3.0%) was much lower than that in non-preventive rhubarb treatment group (11.5%). There was significant difference between two groups (P<0.05). Furthermore, fewer patients developed invasive fungal infection in enteral nutrition support and enteral combined parenteral nutrition support subgroups after preventive rhubarb treatment (0.9% and 2.1%), compared with parenteral nutrition support and no nutrition support subgroups (30.4% and 61.3%) and corresponding subgroups with non-preventive treatment of rhubarb (3.9% and 7.1%, P<0.05 or P<0.01). In addition, the route of nutrition support also affected the incidence of invasive fungal infection. Patients in enteral nutrition support and enteral combined parenteral nutrition support subgroups had lower incidence of invasive fungal infection than in parenteral nutrition support and no nutrition support subgroups (all P<0.05), and the incidence was the highest in no nutrition support subgroup. There were no significant difference between parenteral nutrition support and no nutrition support subgroups. CONCLUSION: Rhubarb and enteral nutrition support have preventive effects on invasive fungal infection via gut mechanism.

[Bone marrow mesenchymal stem cell transplantation aggravates postangioplasty aortic restenosis in rats].

OBJECTIVE: To observe the effect of bone marrow mesenchymal stem cell transplantation on postangioplasty aortic restenosis in rats. METHODS: 48 SD rats were randomly divided into normal control group, balloon injury group, balloon injury and MSCs transplantation group. MSCs were pre-labeled by DAPI (25 microg/ml) and then infused into aorta through the balloon catheter (MSCs 2 x 10(6)/animal). Thoracic aorta were taken for histological examination (frozen and paraffin sections) at 1, 2, 6 weeks post angioplasty, respectively. DAPI labeled MSCs were detected under immunofluorescence microscopy. Expressions of c-kit, proliferating cell nuclear antigen (PCNA), smooth muscle alpha-actin (alpha-SMA) in aorta were determined by immunocytochemistry using related antibodies. RESULTS: The DAPI-labeled MSCs could be detected on impaired intimae and alpha-SMA expression was seen in these cells 1 weeks after MSCs transplantation. Similar weak c-kit expression in neointima was found in both injury and transplantation group at 2 weeks (P > 0.05). Expressions of PCNA and alpha-SMA in the neointima were significantly higher in transplantation group than in injury group at 2 weeks. Intima/tunica media area ratio and luminal stenosis ratio were significantly increased in transplantation group than injury group at 6 weeks (all P < 0.05). CONCLUSION: Bone marrow MSCs transplanted post aortic angioplasty could home to serious wounded aortic intima, differentiate into smooth muscle like cells, promote neointima cellular proliferation and aggravate postangioplasty aortic restenosis in rats.

Combination of dura turning-over and decompressive craniectomy: a new pattern of surgery for cerebral infarction caused by craniocerebral gunshot injury.

BACKGROUND: Craniocerebral gunshot injury refers to a wound caused by a bullet passing through or lodged in brain tissue, resulting in the loss of function of a certain area or other fatal damage to the human brain. Craniocerebral gunshot injury is usually life-threatening and is very common in modern warfare, accounting for the majority of battle casualties. Most of the patients suffer from acute cerebral infarction caused by vascular injury. Lack of early and solid battlefield emergency medical interference adds to the risk of death among the wounded. CASE PRESENTATION: We present a 24-year-old man who was shot with a shotgun from a distance of 15 m in an accidental injury. Forty-seven grapeshots were found on his body surface by physical examination. A computed tomography (CT) scan demonstrated large areas of low-density shadows in his right parietal lobe and right temporal lobe with the midline shifting to the left side 2 days later. Afterwards, the patient was transferred to our emergency medical center at Changzheng Hospital in Shanghai. Cranial computed tomography angiography (CTA) showed a high-density shadow in the initial part of the right middle cerebral artery. The branches after the initial part were obliterated. Prompt medical attention and decompressive craniotomy (DC) surgery contributed to the final recovery from cerebral infarction of this patient. CONCLUSION: Bullets can penetrate or be lodged in the brain, causing intracranial hypertension. The bullets lodged in the brain can result in stenosis and embolism of a cerebral artery, causing acute cerebral infarction. Combining dura turning-over surgery with DC surgery can not only decrease intracranial pressure, which can increase the blood supply for hypertension-induced vessel stenosis, but also help vessels outside the dura mater grow into ischemic areas of the cerebral cortex. However, this new pattern of surgery needs further support from evidence-based medicine.

Thermal sensitivity of bacteriocytes constrains the persistence of intracellular bacteria in whitefly symbiosis under heat stress.

Temperature affects the persistence of diverse symbionts of insects. Our previous study indicates that the whitefly symbionts confined within bacteriocytes or scattered throughout the body cavity outside bacteriocytes may have differential thermal sensitivity. However, the underlying mechanisms remain largely unknown. Here, we report that following continuous heat stress, Portiera and Hamiltonella were almost completely depleted in two species of Middle East-Asia Minor 1 (MEAM1) and Mediterranean (MED) of the Bemisia tabaci whitefly cryptic species complex. Meanwhile, proliferation of bacteriocytes was severely inhibited and approximately 50% of the nymphs had lost one of the two bacteriomes. While cell size of bacteriocytes was increased, cell number was severely decreased leading to reduction of total volume of bacteriocytes. Moreover, bacteriocyte organelles and associated symbionts were lysed, and huge amount of electron-dense inclusions accumulated. Eventually, Portiera and Hamiltonella failed to be transmitted to the next generation. In contrast, Rickettsia could be detected although at a reduced level, and successfully transmitted to eggs. The results suggest that the thermal sensitivity of bacteriocytes may limit thermal tolerance and vertical transmission of the associated symbionts, and consequently different patterns of distribution of symbionts may affect their capacity to tolerate unfavourable temperatures and persistence in the host.

Association of single nucleotide polymorphism rs2076185 in chromosome 6P24.1 with premature coronary artery diseases in Chinese Han population.

OBJECTIVES: To study the association of single nucleotide polymorphism (SNP) rs2076185 in chromosome 6p24.1 with the premature coronary artery diseases (PCAD) in Chinese Han population. METHODS: A total of 1382 patients were divided into the PCAD group and the control group based on their coronary arteriography (CAG) results. Their SNP rs2076185 were analyzed by the mass-spectrometry. Their allele and genotype frequency in Hardy-Weinberg equilibrium were calculated for assessment. Logistic regression was employed to remove confounding factors and correlate SNP rs2076185 with PCAD. RESULTS: The allele and genotype frequencies of the control group were in Hardy-Weinberg equilibrium (P > 0.05). The frequencies of allele G of rs2076185 were 54.2% in the PCAD group and 49.5% in the control group. The difference was significant (P = 0.042). The genotype distribution of rs2076185 of the two groups was also significantly different. The univariate analysis showed that the rs2076185 polymorphisms were associated with the PCAD only in the additive model (OR: 0.828, 95% CI: 0.711-0.964, P = 0.014), and in the dominant model (OR: 0.753, 95% CI: 0.591-0.958, P = 0.021). After removing the confounding variables, the rs2076185 polymorphisms was associated with PCAD in the additive model (OR: 0.775, 95% CI: 0.648-0.928, P = 0.005), in the dominant model (OR: 0.698, 95% CI: 0.527-0.925, P = 0.012), and in the recessive model (OR: 0.804, 95% CI: 0.538-0.983, P = 0.038). CONCLUSION: Allele G of rs2076185 reduces the PCAD risks in Chinese Han population, therefore it could be a coronary artery diseases protective factor in Chinese Han population.

Differential tolerance capacity to unfavourable low and high temperatures between two invasive whiteflies.

Thermal response and tolerance to ambient temperature play important roles in determining the geographic distribution and seasonal abundance of insects. We examined the survival and performance, as well as expression of three heat shock protein related genes, of two species of invasive whiteflies, Middle East-Asia Minor 1 (MEAM1) and Mediterranean (MED), of the Bemisia tabaci species complex following exposure to a range of low and high temperatures. Our data demonstrated that the MED species was more tolerant to high temperatures than the MEAM1 species, especially in the adult stage, and this difference in thermal responses may be related to the heat shock protein related genes hsp90 and hsp70. These findings may assist in understanding and predicting the distribution and abundance of the two invasive whiteflies in the field.

Temporal changes of symbiont density and host fitness after rifampicin treatment in a whitefly of the Bemisia tabaci species complex.

Microbial symbionts are essential or important partners to phloem-feeding insects. Antibiotics have been used to selectively eliminate symbionts from their host insects and establish host lines with or without certain symbionts for investigating functions of the symbionts. In this study, using the antibiotic rifampicin we attempted to selectively eliminate certain symbionts from a population of the Middle East-Asia Minor 1 whitefly of the Bemisia tabaci species complex, which harbors the primary symbiont "Candidatus Portiera aleyrodidarum" and two secondary symbionts "Candidatus Hamiltonella defensa" and Rickettsia. Neither the primary nor the secondary symbionts were completely depleted in the adults (F0) that fed for 48 h on a diet treated with rifampicin at concentrations of 1-100 µg/mL. However, both the primary and secondary symbionts were nearly completely depleted in the offspring (F1) of the rifampicin-treated adults. Although the F1 adults produced some eggs (F2), most of the eggs failed to hatch and none of them reached the second instar, and consequently the rifampicin-treated whitefly colony vanished at the F2 generation. Interestingly, quantitative polymerase chain reaction assays showed that in the rifampicin-treated whiteflies, the density of the primary symbiont was reduced at an obviously slower pace than the secondary symbionts. Mating experiments between rifampicin-treated and untreated adults demonstrated that the negative effects of rifampicin on host fitness were expressed when the females were treated by the antibiotic, and whether males were treated or not by the antibiotic had little contribution to the negative effects. These observations indicate that with this whitefly population it is not feasible to selectively eliminate the secondary symbionts using rifampicin without affecting the primary symbiont and establish host lines for experimental studies. However, the extinction of the whitefly colony at the second generation after rifampicin treatment indicates the potential of the antibiotic as a control agent of the whitefly pest.