Signatures of Positive Selection in the Genome of Apis mellifera carnica: A Subspecies of European Honeybees

The technology of long reads substantially improved the contingency of the genome assembly, particularly resolving contiguity of the repetitive regions. By integrating the interactive fragment using Hi-C, and the HiFi technique, a solid genome of the honeybee Apis mellifera carnica was assembled at the chromosomal level. A distinctive pattern of genes involved in social evolution was found by comparing it with social and solitary bees. A positive selection was identified in genes involved with cold tolerance, which likely underlies the adaptation of this European honeybee subspecies in the north hemisphere. The availability of this new high-quality genome will foster further studies and advances on genome variation during subspeciation, honeybee breeding and comparative genomics.

A Comparison of RNA Interference via Injection and Feeding in Honey Bees

RNA interference (RNAi) has been used successfully to reduce target gene expression and induce specific phenotypes in several species. It has proved useful as a tool to investigate gene function and has the potential to manage pest populations and reduce disease pathogens. However, it is not known whether different administration methods are equally effective at interfering with genes in bees. Therefore, we compared the effects of feeding and injection of small interfering RNA (siRNA) on the messenger RNA (mRNA) levels of alpha-aminoadipic semialdehyde dehydrogenase (ALDH7A1), 4-coumarate-CoA ligase (4CL), and heat shock protein 70 (HSP70). Both feeding and injection of siRNA successfully knocked down the gene but feeding required more siRNA than the injection. Our results suggest that both feeding and injection of siRNA effectively interfere with brain genes in bees. The appropriateness of each method would depend on the situation.

[HCV and Treponema pallidum infection status in HIV/AIDS cases in Yunnan province, January-June, 2020]

Objective: To understand the infection status of HCV and Treponema pallidum (TP) in HIV/AIDS cases in Yunnan province,and identify the risk factors. Methods: Between January 1 and June 30 in 2020,a cross-sectional survey was conducted in Yunnan. Two enzyme-linked immunosorbent assay (ELISA) kits were used to detect anti-HCV, the positive results of both two kits indicated HCV infection. ELISA and syphilis toluidine red untreated serum test were applied to identify TP infection. Both Excel 2016 and SPSS 22.0 software were used for statistical analysis, and logistic regression model was conducted to identify the relevant factors of HCV and TP infection. Results: A total of 5 922 HIV/AIDS cases were included in this study, the infection rates of HCV and TP were 6.5% (383/5 922) and 5.8% (344/5 922) respectively. The co-infection rate of HCV and TP was 0.4% (22/5 922). The risk for HCV infection in HIV/AIDS cases was higher in younger age groups compared with age group ≥50 years (15-19:aOR=3.53;20-29:aOR=3.02;30-39:aOR=2.91;40-49:aOR=3.61), in males than in females (aOR=2.31), in the married and unmarried than in the divorced or widowed (married:aOR=1.61;unmarried:aOR=1.63), in other ethnic groups than in Han ethnic group (aOR=1.70), in people with lower education level than in people with education level of college and above (primary school degree and below:aOR=4.69;middle school:aOR=3.96), in people living in the central and western Yunnan than in people living in eastern Yunnan (central Yunnan:aOR=2.46; western Yunnan:aOR=7.08), in injection drug users than in MSM (aOR=131.08). The risk of TP infection in HIV/AIDS cases was higher in people with education level of college and primary school than in middle school degree (primary school and below:aOR=1.73;college and above:aOR=1.77), in people with other occupations than in farmers (aOR=1.39), in people living in eastern Yunnan than in people living in western Yunnan (aOR=1.75); in MSM than in people with heterosex (aOR=9.75). Conclusions: A certain proportion of HIV/AIDS cases reported between January and June in 2020 in Yunnan were co-infected with HCV and TP, many factors were associated with the co-infection. It is suggested to strengthen HCV and TP tests in HIV/AIDS cases and conduct active treatment of the co-infection.

[Characteristics of HIV-1 genotype and drug resistance among men who have sex with men in Kunming, 2018]

Objective: To understand the characteristics of HIV-1 genotypes and drug resistance among men who have sex with men in Kunming in 2018. Methods: A total of 193 plasma samples were collected from the newly reported HIV-1 infected MSM in Kunming from January to December 2018. Viral RNA was extracted, and the gag, pol, env gene segments were amplified by nested PCR. HIV-1 genotypes and drug resistance were also analyzed. Subsequently, the evolutionary characteristics of CRF55_01B and CRF68_01B among MSM in Kunming were analyzed by Bayesian Markov Chain Monte Carlo method. Results: Multiple HIV-1 genotypes were identified among these 193 samples, including CRF07_BC (39.4%, 76/193), CRF01_AE (34.2%, 66/193), unique recombinant forms (URFs) (20.2%, 39/193), CRF08_BC (3.1%, 6/193), CRF55_01B (1.6%, 3/193), subtype B (1.0%, 2/193) and CRF68_01B (0.5%, 1/193). Results from the Bayesian evolutionary analysis showed that CRF55_01B started to spread locally after being imported from other provinces, while CRF68_01B was likely to have been brought in from the eastern provinces of China. Prevalence of HIV-1 drug resistant strains was 2.6%(5/190) before antiviral treatment, with mutation rates resistant to non-nucleoside reverse transcriptase inhibitors being the highest (2.1%, 4/190) among MSM in Kunming, 2018. Conclusion: The diversity of HIV-1 was increasing among MSM in Kunming. Although the resistance rate on pretreatment drug was relatively low, the emergence of multiple resistant strains to first-line antiviral drugs posed a challenge to antiretroviral therapy, in Kunming.

Clinical outcomes of revision with retrograde intermedullary nailing for failed plating of distal femoral fractures: a retrospective study

PURPOSE

To assess the feasibility and effectiveness of retrograde intramedullary nail (RIN) revision surgeries for locking compression plate (LCP) failure in distal femoral fractures.

METHODS

This retrospective study included 13 patients who suffered from metalwork failures after they initially underwent open reduction and LCP fixation. In patients who eventually underwent RIN revision from January 2014 to December 2016, range of motion (ROM) and Hospital for Special Surgery (HSS) scores obtained before surgery and at the final follow-up time were analysed.

RESULTS

The average operative time was 155 minutes (range, 120-210 minutes), and the average blood loss volume was 650 ml (range, 200-1350 ml). There were two cases of complications (15.38%): one was calf muscle vein thrombosis, and the other was a superficial infection. No deep tissue infection or deep vein thrombosis was observed post-operatively. The average follow-up time was 16 months (range, 12-24 months). All fractures healed in a mean of 6.5 months (range, 4-12 months), and one patient underwent an additional bone graft surgery that did not involve a bone graft during the RIN revision operation (this eventually healed at 12 months post-operatively). The mean ROM before the operation was 86.92 ± 12.34°. At the final follow-up, the mean ROM was 112.69 ± 9.27°. There was a significant difference between pre-operative and post-operative ROM (P < 0.01). The mean HSS score improved significantly from 38.85 ± 9.62 points pre-operatively to 79.62 ± 5.42 points post-operatively. There was a significant difference between pre-operative and post-operative HSS scores (P < 0.01).

CONCLUSIONS

RIN revision surgery achieved excellent clinical results in patients with LCP failure.

A Chromosome-Scale Assembly of the Asian Honeybee Apis cerana Genome

Apis cerana is one of the main honeybee species in artificial farming, which is widely distributed in Asian countries. The genome of A. cerana has been sequenced by several different research groups using second generation sequencing technologies. However, it is still necessary to obtain more complete and accurate genome sequences. Here we present a chromosome-scale assembly of the A. cerana genome using single-molecule real-time (SMRT) Pacific Biosciences sequencing and high-throughput chromatin conformation capture (Hi-C) genome scaffolding. The updated assembly is 215.67 Mb in size with a contig N50 of 4.49 Mb, representing an 212-fold improvement over the previous Illumina-based version. Hi-C scaffolding resulted in 16 pseudochromosomes occupying 97.85% of the assembled genome sequences. A total of 10,741 protein-coding genes were predicted and 9,627 genes were annotated. Besides, 314 new genes were identified compared to the previous version. The improved high-quality A. cerana reference genome will provide precise sequence information for biological research of A. cerana.

A comparison of honeybee (Apis mellifera) queen, worker and drone larvae by RNA-Seq

Honeybees (Apis mellifera) have haplodiploid sex determination: males develop from unfertilized eggs and females develop from fertilized ones. The differences in larval food also determine the development of females. Here we compared the total somatic gene expression profiles of 2-day and 4-day-old drone, queen and worker larvae by RNA-Seq. The results from a co-expression network analysis on all expressed genes showed that 2-day-old drone and worker larvae were closer in gene expression profiles than 2-day-old queen larvae. This indicated that for young larvae (2-day-old) environmental factors such as larval diet have a greater effect on gene expression profiles than ploidy or sex determination. Drones had the most distinct gene expression profiles at the 4-day larval stage, suggesting that haploidy, or sex dramatically affects the gene expression of honeybee larvae. Drone larvae showed fewer differences in gene expression profiles at the 2-day and 4-day time points than the worker and queen larval comparisons (598 against 1190 and 1181), suggesting a different pattern of gene expression regulation during the larval development of haploid males compared to diploid females. This study indicates that early in development the queen caste has the most distinct gene expression profile, perhaps reflecting the very rapid growth and morphological specialization of this caste compared to workers and drones. Later in development the haploid male drones have the most distinct gene expression profile, perhaps reflecting the influence of ploidy or sex determination on gene expression.

Short-Term Exposure to Lambda-Cyhalothrin Negatively Affects the Survival and Memory-Related Characteristics of Worker Bees Apis mellifera

Pesticides are considered one of the major contemporary stressors of honey bee health. In this study, the effects of short-term exposure to lambda-cyhalothrin on lifespan, learning, and memory-related characteristics of Apis mellifera were systematically examined. Short-term exposure to lambda-cyhalothrin in worker bees reduced lifespan, affected learning and memory performance, reduced the homing ability, and influenced the expression levels of two learning and memory-related genes of A. mellifera. This research identifies the nature of the sublethal effects of lambda-cyhalothrin on bees and the level of exposure that can be harmful to bee health. This new information will assist in establishing guidelines for the safe use of lambda-cyhalothrin in the field.

Molecular cloning and expression analysis of the tyramine <br/>receptor genes in Apis cerana cerana

Tyramine is a biological polyamine, which serves important functions as neurotransmitters, neuromodulators and neurohormone of the central nervous system. It participates in the regulation of various behavior and physiological processes in insects. For example, tyramine and its receptor genes are involved in the regulation of learning and memory in the animals. In this study, the full-length cDNA sequences of the tyramine receptor genes (Actyr1 and Actyr2) of the Chinese honeybee, Apis cerana cerana, were cloned and sequenced for the first time. Their expression patterns were examined in different tissues by qRT-PCR and localized in the head by in situ hybridization with digoxigenin (DIG)-labeled RNA probes. The full-length cDNAs of Actyr1 and Actyr2 are 1241 bp (GenBank accession no. KC814693) and 1270 bp (GenBank accession no.KC814693) in length and encode 297 amino acids and 399 amino acids, respectively. qRT-PCR results showed that the expression levels of both Actyr1 and Actyr2 were the highest in the head, followed by the abdomen, then the antennae and the lowest in the thorax. The expression level in the head was significantly higher than that in other tissues. Moreover, in situ hybridization showed that the expression of Actyr1 and Actyr2 genes were mainly localized to the Kenyon cells of the mushroom bodies and cells around the antennal lobes. These observations suggest that some interactions between these two genes in certain cells could be important in regulating various biological functions, such as learning and memory, in the honeybee.

Varroa destructor changes its cuticular hydrocarbons to mimic new hosts

Varroa destructor (Vd) is a honeybee ectoparasite. Its original host is the Asian honeybee, Apis cerana, but it has also become a severe, global threat to the European honeybee, Apis mellifera. Previous studies have shown that Varroa can mimic a host's cuticular hydrocarbons (HC), enabling the parasite to escape the hygienic behaviour of the host honeybees. By transferring mites between the two honeybee species, we further demonstrate that Vd is able to mimic the cuticular HC of a novel host species when artificially transferred to this new host. Mites originally from A. cerana are more efficient than mites from A. mellifera in mimicking HC of both A. cerana and A. mellifera. This remarkable adaptability may explain their relatively recent host-shift from A. cerana to A. mellifera.

The integrative analysis of microRNA and mRNA expression in Apis mellifera following maze-based visual pattern learning

The honeybee (Apis mellifera) is a social insect with strong sensory capacity and diverse behavioral repertoire and is recognized as a good model organism for studying the neurobiological basis of learning and memory. In this study, we analyzed the changes in microRNA (miRNA) and messenger RNA (mRNA) following maze-based visual learning using next-generation small RNA sequencing and Solexa/lllumina Digital Gene Expression tag profiling (DGE). For small RNA sequencing, we obtained 13 367 770 and 13 132 655 clean tags from the maze and control groups, respectively. A total of 40 differentially expressed known miRNAs were detected between these two samples, and all of them were up-regulated in the maze group compared to the control group. For DGE, 5 681 320 and 5 939 855 clean tags were detected from the maze and control groups, respectively. There were a total of 388 differentially expressed genes between these two samples, with 45 genes up-regulated and 343 genes down-regulated in the maze group, compared to the control group. Additionally, the expression levels of 10 differentially expressed genes were confirmed by quantitative reverse transcription polymerase chain reaction (qRT-PCR) and the expression trends of eight of them were consistent with the DGE result, although the degree of change was lower in amplitude. The integrative analysis of miRNA and mRNA expression showed that, among the 40 differentially expressed known miRNAs and 388 differentially expressed genes, 60 pairs of miRNA/mRNA were identified as co-expressed in our present study. These results suggest that both miRNA and mRNA may play a pivotal role in the process of learning and memory in honeybees. Our sequencing data provide comprehensive miRNA and gene expression information for maze-based visual learning, which will facilitate understanding of the molecular mechanisms of honeybee learning and memory.

[Study on foraging behaviors of honeybee Apis mellifera based on RFID technology]

Honeybee foragers can flexibly adjust their out-hive activities to ensure growth and reproduction of the colony. In order to explore the characteristics of honey bees foraging behaviors, in this study, their flight activities were monitored 24 hours per day for a duration of 38 days, using an radio frequency identification (RFID) system designed and manufactured by the Honeybee Research Institute of Jiangxi Agricultural University in cooperation with the Guangzhou Invengo Information Technology Co., Ltd. Our results indicated that 63.4% and 64.5% of foragers were found rotating more than one day off during the foraging period in two colonies, and 22.5% and 26.4% of the total foraging days were used for rest respectively. Further, although the total foraging time between rotating day-off foragers and continuously working foragers was equal, the former had a significant longer lifespan than the latter. Additionally, the lifespan of the early developed foragers was significantly lower than that of the normally developed foragers. This study enriched the content of foraging behaviors of honey bees, and it could be used as the basis for the further explorations on evolutionary mechanism of foraging behaviors of eusocial insects.

Optimal combination of radiotherapy and endocrine drugs in breast cancer treatment

PURPOSE

Breast cancer is the most common cancer in women. Radiotherapy is considered a standard treatment option after surgery and adjuvant endocrine therapy is also universally used. Tamoxifen and letrozole are the current first-line endocrine therapy drugs. However, information has been scarce about how best to sequence these therapies to maximize their effectiveness and keep toxic effects to a minimum. In this study, we observed the effect of different sequence combination of radiotherapy and endocrine drugs, tamoxifen or letrozole, to get the best treatment sequence.

MATERIALS AND METHODS

The combination effect of radiotherapy and tamoxifen was observed on breast tumour cell line MCF-7, radiotherapy and letrozole on aromatase-expressing breast tumour cell line MCF-7CA. Irradiation was performed with 6Gy, except for doses ranging from 0 to 8Gy for clone formation assay. Tamoxifen or letrozole was added before or after irradiation, respectively. Radiosensitivity was evaluated by clonogenic assay, cell viability by 3-(4,-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium, inner salt (MTS) assay. To explore the potential mechanism, cell apoptosis was determined by DNA-binding dye 4',6-diamidino-2-phenylindole dihydrochloride (DAPI) assay, the change of Bcl-2 and Bax expression was by western blot.

RESULTS

Although no significant statistical difference was observed between different sequence, tamoxifen and letrozole both increased radiosensitivity. Furthermore, the above inhibitory effect was related with apoptosis signaling pathway, especially Bcl-2 and Bax.

CONCLUSION

Taken together, these results suggested that endocrine drugs, such as tamoxifen and letrozole, have potential application with radiotherapy.

Gene expression analysis following olfactory learning in Apis mellifera

The honeybee has a strong learning and memory ability, and is recognized as the best model organism for studying the neurobiological basis of learning and memory. In this study, we analyzed the gene expression difference following proboscis extension response-based olfactory learning in the A. mellifera using a tag-based digital gene expression (DGE) method. We obtained about 5.71 and 5.65 million clean tags from the trained group and untrained group, respectively. A total of 259 differentially expressed genes were detected between these two samples, with 30 genes up-regulated and 229 genes down-regulated in trained group compared to the untrained group. These results suggest that bees tend to actively suppress some genes instead of activating previously silent genes after olfactory learning. Our DGE data provide comprehensive gene expression information for olfactory learning, which will facilitate our understanding of the molecular mechanism of honey bee learning and memory.