[Randomized controlled study on the application effect of a new type of intravenous radiofrequency closed therapy system made in China and an imported system]

Objective: To compare the application effect of domestic and imported intravenous radiofrequency closure system in the treatment of primary varicose veins of lower extremities. Methods: This single-center prospective, non-inferiority randomized controlled trial was performed in the Department of Vascular Surgery, the Fourth Affiliated Hospital, Zhejiang University School of Medicine from January 2021 to January 2022. Patients with primary varicose veins of lower extremities who met the ataxation criteria were randomly assigned to the experimental group(domestic novel venous radiofrequency closure system) or the control group(imported venous radiofrequency closure system) in a ratio of 1∶1. The two groups of subjects were compared in terms of target vein closure rate, technical success rate, system operation performance, incidence of adverse events and incidence of serious adverse events(SAE) within 6 months after surgery. Quantitative data were compared by Mann-Whitney U test, and categorical data were compared by χ2 test and non-inferiority test. Results: A total of 80 subjects were included in the trial (41 in the experimental group and 39 in the control group), including 27 males and 53 females, aged (M(IQR)) 55(23) years (range:40 to 78 years). There were 48 cases of left lower limb and 32 cases of right lower limb. The technical success rate and system control performance between the groups were 100%.The incidence of adverse events (58.5% (24/41) vs. 61.5% (24/39), χ2=0.075, P=0.784), and the incidence of SAE (7.3% (3/41) vs. 5.1% (2/39), χ2=0.163, P=0.686) within 6 months after surgery in experimental group and control group had no statistical significance. There was one device-related adverse event in each of the two groups. In the experimental group, one patient developed endovenous heat-induced thrombosis after surgery and recovered after taking rivaroxaban tablets. One patient in the control group had pain in the upper right thigh for more than 1 day after operation, which was cured after using analgesic cream. No device-related SAE occurred. The venous closure rate of the experimental group was 100% (38/38) at 6 months after surgery, and that of the control group was 97.4% (37/38). The difference between the two groups was 2.63% (95%CI:-3.19 to 8.45, Z=4.865, P<0.01), and the 95%CI lower limit of the difference in target venous closure rate between two groups was greater than the non-inferiority threshold of -10.00%. Conclusion: The early application effect of the new domestic intravenous radiofrequency closure system in patients with primary varicose veins of lower extremities is in line with expectations, it is not inferior to the imported system.

A Global Survey of the Full-Length Transcriptome of Apis mellifera by Single-Molecule Long-Read Sequencing

As important pollinators, honey bees play a crucial role in both maintaining the ecological balance and providing products for humans. Although several versions of the western honey bee genome have already been published, its transcriptome information still needs to be refined. In this study, PacBio single-molecule sequencing technology was used to sequence the full-length transcriptome of mixed samples from many developmental time points and tissues of A. mellifera queens, workers and drones. A total of 116,535 transcripts corresponding to 30,045 genes were obtained. Of these, 92,477 transcripts were annotated. Compared to the annotated genes and transcripts on the reference genome, 18,915 gene loci and 96,176 transcripts were newly identified. From these transcripts, 136,554 alternative splicing (AS) events, 23,376 alternative polyadenylation (APA) sites and 21,813 lncRNAs were detected. In addition, based on the full-length transcripts, we identified many differentially expressed transcripts (DETs) between queen, worker and drone. Our results provide a complete set of reference transcripts for A. mellifera that dramatically expand our understanding of the complexity and diversity of the honey bee transcriptome.

[Influence of age on advanced neoplasia detection in colorectal cancer screening in population at high risk]

Objective: To compare the detection rate of advanced neoplasia and the number of people needing endoscopy in colorectal cancer screening giving at different starting age in population at high risk. Methods: Based on the screening project of early diagnosis and treatment of colorectal cancer in Jiashan county, Zhejiang province, two rounds of colorectal cancer screening were conducted between January 2007 and December 2020. After excluding participants who were not at high risk or had incomplete information, 27 130 participants and 31 205 participants were finally enrolled in round one and in round two, respectively. The spline analysis based on the generalized additive model was used to describe the trend of detection rate of advanced neoplasia with age. The detection rate and number of people needing endoscopy for the groups with starting age at 50, 45 and 40 years were calculated, and the differences in the detection rate were tested by χ² goodness of fit test. Results: A total of 21 077 (77.69%) participants in round one and 25 249 (80.91%) participants in round two received endoscopy, in whom 1 097 (detection rate=52.05‰) and 1 151 (detection rate=45.59‰) had advanced neoplasia (cancers and advanced adenomas), respectively. The detection rate increased significantly with age, and the detection rate in round one were significantly higher than that in round two (P<0.05). The overall detection rates of advanced neoplasia for the groups with starting age at 50, 45 and 40 years were 61.11‰, 56.14‰ and 52.05‰ in round one, and 49.10‰, 46.75‰ and 45.59‰ in round two, respectively. The rates were significantly higher for the group with starting age at 50 years than that with starting age at 40 years in both round one and round two (P<0.05). The numbers of people needing endoscopy of advanced neoplasia for the groups with starting age at 50, 45 and 40 years were 17, 18, and 20 in round one, and 21, 22 and 22 in round two. Conclusions: The detection rate of advanced neoplasia increased with age. Starting screening at lower age might contribute to decreased detection rate and increased number of people needing endoscopy. However, the difference was limited.

[Influence of age on advanced neoplasia detection in colorectal cancer screening in population at high risk]

Objective: To compare the detection rate of advanced neoplasia and the number of people needing endoscopy in colorectal cancer screening giving at different starting age in population at high risk. Methods: Based on the screening project of early diagnosis and treatment of colorectal cancer in Jiashan county, Zhejiang province, two rounds of colorectal cancer screening were conducted between January 2007 and December 2020. After excluding participants who were not at high risk or had incomplete information, 27 130 participants and 31 205 participants were finally enrolled in round one and in round two, respectively. The spline analysis based on the generalized additive model was used to describe the trend of detection rate of advanced neoplasia with age. The detection rate and number of people needing endoscopy for the groups with starting age at 50, 45 and 40 years were calculated, and the differences in the detection rate were tested by χ² goodness of fit test. Results: A total of 21 077 (77.69%) participants in round one and 25 249 (80.91%) participants in round two received endoscopy, in whom 1 097 (detection rate=52.05‰) and 1 151 (detection rate=45.59‰) had advanced neoplasia (cancers and advanced adenomas), respectively. The detection rate increased significantly with age, and the detection rate in round one were significantly higher than that in round two (P<0.05). The overall detection rates of advanced neoplasia for the groups with starting age at 50, 45 and 40 years were 61.11‰, 56.14‰ and 52.05‰ in round one, and 49.10‰, 46.75‰ and 45.59‰ in round two, respectively. The rates were significantly higher for the group with starting age at 50 years than that with starting age at 40 years in both round one and round two (P<0.05). The numbers of people needing endoscopy of advanced neoplasia for the groups with starting age at 50, 45 and 40 years were 17, 18, and 20 in round one, and 21, 22 and 22 in round two. Conclusions: The detection rate of advanced neoplasia increased with age. Starting screening at lower age might contribute to decreased detection rate and increased number of people needing endoscopy. However, the difference was limited.

[The GTP-Bound form of Rab3D Promotes Lipid Droplet Growth in Adipocyte]

Rab GTPases are major regulators of membrane trafficking. Proteome profiling reveals dozens of Rab proteins associated with lipid droplets (LDs), but few of them have been functionally validated. Cell death activator CIDE-3 protein mediates LD fusion and growth. It is highly enriched at LD-LD contact sites. Here, we investigated the role of Rab3D in lipid storage in adipocyte. We verified that the adipose levels of Rab3D transcript were higher than that of other Rab3 family members; the differences were most pronounced in white adipose tissue. Moreover, we showed that Rab3D promotes LD growth in 3T3-L1 preadipocytes in a dose dependent manner, independently of the process of CIDE-3-mediated LD fusion. Finally, we confirmed that the GTP-bound form of Rab3D is its LD promoting form; it translocates from other vesicles to LDs during adipocyte differentiation. By contrast, the Rab3D-GDP form is retained in the cytoplasm and has no effect on LD sizes. Presented results provide evidence for the role of Rab3D in controlling formation of large LDs in adipocytes. We conclude that Rab3D is a novel LD regulator with characteristics differing from these of previously identified LD associated Rab proteins, such as Rab18 and Rab8a.

[Association between sleep and prevalence of hypertension in elderly population]

Objective: To explore the association between sleep duration, sleep quality and the prevalence of hypertension in the elderly aged 65 years and above. Methods: This study was conducted among the elderly in communities in Yiwu, China from April to July, 2019, and participants were recruited through physical examination in the hospital. Face-to-face interview was performed to obtain basic information. Sleep duration and sleep quality were evaluated by Pittsburgh Sleep Quality Index (PSQI). Associations between sleep duration, sleep quality and hypertension were evaluated by multivariate logistic regression analysis. Results: A total of 3 169 elderly persons, aged ≥65 years old, were included in the study. The overall prevalence of hypertension was 50.8%. The elderly with very poor sleep quality and short sleep duration accounted for 22.4% and 28.5%, respectively. After adjusting for demographic characteristics, socioeconomic status, lifestyle and health status, the OR of hypertension for the elderly with very poor sleep quality was 1.42 (95%CI: 1.12-1.80) compared with those with very good sleep quality. Compared with the elderly with sleep duration of 6-7 h a night, the OR of hypertension for those with sleep duration <6 h was 1.37 (95%CI: 1.15-1.65). As the sleep quality decreased, the risk for hypertension increased. An U-shaped association was found between sleep duration and risk of hypertension. Subgroup analyses showed that this association existed in both men and women, but only significant in the elderly aged <75 years. Conclusion: Poor sleep quality and short sleep duration were associated with risk for hypertension in the elderly.

[Association between lifestyle-related factors and colorectal adenoma]

Objective: To explore the association between lifestyle-related factors and colorectal adenoma. Methods: Based on the Screening Project of Early Diagnosis and Treatment of Colorectal Cancer in Jiashan county Zhejiang province, from August 2012 to March 2018, information gathered through records on questionnaire and colonoscopic diagnosis were collected from participants with positive results during the primary screening stage. According to the findings of colonoscopy, 11 232 controls without any colorectal diseases and 3 895 cases with colorectal adenoma were included in the study. Multivariate logistic regression models were used to analyze the association between lifestyle-related factors and colorectal adenoma. Results: After adjusting for possible confounding factors, results from multivariate logistic regression analysis showed that smoking, alcohol drinking and obesity were positively related to the risk of colorectal adenoma, with ORs (95%CIs) as 1.38 (1.24-1.54), 1.37 (1.24-1.51) and 1.38 (1.20-1.59) respectively. However, regular aspirin intake was negatively related with the risk of colorectal adenoma (OR=0.65, 95%CI: 0.53-0.80). After stratified by sex and age, data showed that the associations between smoking, alcohol drinking and colorectal adenoma were statistically significant in males, and the association between regular aspirin intake and colorectal adenoma was also statistically significant in older participants (aged 60 years and older). Conclusion: Smoking, alcohol drinking, regular aspirin intake and obesity were associated with colorectal adenoma.

[Heavy Metal Pollution Characteristics and Ecological and Health Risk Assessment of Atmospheric PM2.5 in a Living Area of Zhengzhou City]

To study the pollution characteristics of atmospheric heavy metal elements in a living area of Zhengzhou City, assess the potential ecological risks, and determine risks to resident health in this city, the Wuhan Tianhong TH-16A Airborne Particles Intelligent Sampler was used to collect atmospheric PM_2.5 in Zhengzhou City. The mass concentrations of 17 metal elements were analyzed by ambient air determination of inorganic elements by ambient particle matter wavelength dispersive X-ray fluorescence spectrometry. The source of heavy metals was analyzed by the enrichment factor method and principal component analysis. The ecological risk index method and the US Environmental Protection Agency's health risk assessment method were used to evaluate the potential ecological risks and residents' health risks from Cr, Cd, Cu, Zn, Ni, Pb, As, and other elements. The results showed that metals with higher enrichment factor values were Cd, Sb, Pb, and As, and Cd had the highest enrichment factor value. The sources of metal elements in a living area of Zhengzhou City were mainly crust/burning coal, fuel, garbage burning, metallurgical dust, and vehicle emission. The single factor potential ecological hazard index values of Cd, Pb, Zn, As, Cu, Ni, and Cr were 70420.2, 255.3, 204.6, 71.5, 36.9, 24.0, and 5.1, respectively. Cd, As, and Cr in a living area of Zhengzhou City posed a cancer risk, and Cd was the most harmful. Mn had a non-carcinogenic risk.

[Emission Characteristics Analysis and Health Risk Assessment of Unorganized VOCs in the Carbon Industry, Zhengzhou]

The three typical carbon enterprises in Zhengzhou were selected as research targets, and the emission characteristics of volatile organic compounds (VOCs) and their ozone formation potential (OFP) in different functional areas were studied. The US Environmental Protection Agency (EPA) health risk assessment model was used to evaluate the health risks of VOCs emitted by the carbon industry. The results showed that the concentration of VOCs in the production areas of the three research enterprises was between 89.77-964.60 μg·m^-3, and the management area was between 51.46-121.59 μg·m^-3. Naphthalene and carbon disulfide were at the highest concentrations in the carbon plants. The ozone formation potential of VOCs in the production area was between 75.42-1416.73 μg·m^-3, and in the management area was between 65.32-202.42 μg·m^-3, mainly from the contribution of aromatic hydrocarbons and olefins. The carcinogenic health risk (Risk) of VOCs in the production area was 3.5×10^-5-2.8×10^-3, and in the management area was 2.0×10^-5-9.4×10^-5, which was higher than the maximum acceptable level recommended by the EPA (10^-6). The non-carcinogenic health risk index (HI) of the VOCs in the production area was 3.2-1.4×10², and in the management area was 4.3×10^-1-3.8, except for the management area of the first enterprise, which was greater than 1, which may expose the workers. These health factors cause cancer and non-carcinogenic hazards.

[Cost-effectiveness analysis on colorectal cancer screening program]

Objective: To evaluate the cost-effectiveness of colorectal cancer screening program in different age groups from the view of health economics. Methods: The screening compliance rates, detection rates in different age groups were calculated by using the data from colorectal cancer screening program in Jiashan county, Zhejiang province. The differences in indicator among age groups were analyzed with χ(2) test or trend χ(2) test. The ratios of cost to the number of case were calculated according to cost statistics. Results: The detection rates of immunochemical fecal occult blood test (iFOBT) positivity, advanced adenoma and colorectal cancer and early stage cancer increased with age, while the early diagnosis rates were negatively associated with age. After exclusion the younger counterpart, the cost-effectiveness of individuals aged >50 years could be reduced by 15%-30%. Conclusion: From health economic perspective, it is beneficial to start colorectal cancer screening at age of 50 years to improve the efficiency of the screening.

Genetic Differentiation in Native and Introduced Populations of Cryptolaemus montrouzieri (Coleoptera: Coccinellidae) and Its Implications for Biological Control Programs

Cryptolaemus montrouzieri Mulsant (Coleoptera: Coccinellidae) is an effective biological control agent of Australian origin, which has been introduced worldwide to control mealybugs. Although successfully used for >100 yr, its introduction in a new area may cause environmental risks should the populations become invasive. In the present study, a population genetics method was used to make predictions of the invasive potential of C. montrouzieri. Our results showed a similar level of genetic diversity among all populations. No significant genetic differentiation between native and introduced populations was observed, while three populations from the native region were significantly divergent. The fact that genetic diversity was not reduced in introduced areas suggests that no bottleneck effect has occurred during introduction. To avoid rapid evolution of the introduced C. montrouzieri, the introduction records of each population should be clearly traced and introductions from multiple sources into the same area should be avoided.

Description of two new species of the genus Megophrys (Amphibia: Anura: Megophryidae) from Heishiding Nature Reserve, Fengkai, Guangdong, China, based on molecular and morphological data

Two new species, Megophrys acuta sp. nov. and Megophrys obesa sp. nov., are described based on a series of specimens collected from Heishiding Nature Reserve, Fengkai County, Guangdong Province, China. They can be distinguished from other known congeners occurred in southern and eastern China by morphological characters and molecular divergence in the mitochondrial 16S rRNA gene. M. acuta is characterized by small and slender body with adult females measuring 28.1-33.6 mm and adult males measuring 27.1-33.0 mm in snout-vent length; snout pointed, strongly protruding well beyond margin of lower jaw; canthus rostralis well developed and sharp; hindlimbs short, the heels not meeting, tibio-tarsal articulation reaching forward the pupil of eye. M. obesa is characterized by stout and slightly small body with adult females measuring 37.5-41.2 mm, adult male measuring 35.6 mm in snout-vent length; snout round in dorsal view; canthus rostralis developed; hindlimbs short, the heels not meeting, tibio-tarsal articulation reaching forward the posterior margin of eye. The discovery of these two new species further confirms that the diversity of this genus has been significantly underestimated. At present the genus Megophrys contains 56 species of which 35 species are distributed in China.

Associations of lifestyle-related factors, hsa-miR-149 and hsa-miR-605 gene polymorphisms with gastrointestinal cancer risk

To explore the associations of SNPs within hsa-miR-605 (rs2043556) and hsa-miR-149 (rs2292832) and lifestyle-related factors with gastrointestinal cancer, a case-control study including 762 cases and 757 controls was conducted. Marginally significant associations were found both for hsa-miR-149 rs2292832 with gastric cancer risk (TC + CC vs. TT, OR = 0.68, 95% CI: 0.44-1.04) and for hsa-miR-605 rs2043556 with colorectal cancer risk (AG + GG vs. AA, OR = 0.70, 95% CI: 0.48-1.02) in males. Tea drinking showed a protective effect on gastric cancer risk (OR = 0.28, 95% CI: 0.13-0.60), while smoke inhalation increased the risk of gastric cancer (OR = 1.94, 95% CI: 1.08-3.47). Irritability was found to be a risk factor for both colorectal cancer (OR = 1.61, 95% CI: 1.02-2.53) and gastric cancer (OR = 1.96, 95% CI: 1.17-3.29). Among those that engaged in smoke inhalation, miR-149 CT/CC and miR-605 AG/GG genotype carriers had increased susceptibilities to colorectal cancer (OR = 1.90, 95% CI: 1.11-3.25) and gastric cancer (OR = 1.87, 95% CI: 1.03-3.42), respectively. Among the tea drinkers, there exists a marginally protective effect of miR-605 AG/GG genotypes on colorectal cancer incidence (OR = 0.71, 95% CI: 0.47-1.06) and a significantly protective effect of miR-149 CT/CC on gastric cancer incidence (OR = 0.47, 95% CI: 0.29-0.77). The SNPs of rs2292832 and rs2043556 might be able to modify the susceptibility to male gastric and colorectal cancers, respectively. Tea drinking is a protective factor, while smoke inhalation is a risk factor for gastric cancer, and they might have the potential to modify the associations between miR-149 and miR-605 polymorphisms with gastrointestinal cancer risk. In addition, irritability was shown to be a risk factor for both gastric and colorectal cancers.

Hepatitis B virus X protein enhances COX-2 expression in human liver cell line L-02

AIM: To investigate the effect of hepatitis B virus X protein (HBx) on COX-2 expression in human liver cell line L-02.

METHODS: HBx expression vector pIRES2-AcGFP-HBx was constructed and transfected into L-02 cells. The expression of COX-2 mRNA and protein was detected by RT-PCR and Western blot, respectively. The effect of HBx protein on cell division and proliferation was evaluated by plotting cell growth curve and analyzing cell cycle. Moreover, pGL3-COX-2 plasmid, in which the COX-2 promoter has been linked to the luciferase reporter gene, was transfected into L-02 cells and luciferase activities were measured.

RESULTS: RT-PCR results revealed that HBx mRNA was expressed only in cells transfected with the HBx gene, and that COX-2 mRNA expression in cells transfected with the HBx gene was higher than that in cells untranfected or transfected with an empty vector (0.76 ± 0.12 vs 0.28 ± 0.04, 0.25 ± 0.03, both P < 0.01). Western blot analysis showed that HBx protein was expressed only in cells transfected with the HBx gene, and COX-2 protein expression in this group was higher than that in the two control groups. The proliferation of cells transfected with the HBx gene was faster than that of control cells (both P < 0.05). The numbers of cells in S and G2-M phases significantly increased while those in G₀-G₁ phase decreased in cells transfected with the HBx gene compared to control cells (all P < 0.05). The luciferase activity in cells transfected with the HBx gene was higher than that in control cells (1 675.2 ± 84.9 vs 657.7 ± 34.7, 739.3 ± 45.3, both P < 0.05).

CONCLUSION: HBx protein can enhance COX-2 expression by up-regulating the activity of COX-2 promoter and promote cell growth, division and proliferation in human liver cell line L-02.

Requirements for efficient production and transduction of human immunodeficiency virus type 1-based vectors

A number of human immunodeficiency type 1 (HIV-1)-based vectors have recently been shown to transduce nondividing cells in vivo as well as in vitro. However, if these vectors are to be considered for eventual clinical use, a major consideration is to reduce the probability of unintended generation of replication-competent virus. This can be achieved by eliminating viral genetic elements involved in the generation of replication-competent virus without impairing vector production. We have designed a system to transiently produce HIV-1-based vectors by using expression plasmids encoding Gag, Pol, and Tat of HIV-1 under the control of the cytomegalovirus immediate-early promoter. Our data show that the best vector yield is achieved in the presence of the Rev/Rev-responsive element (RRE) system. However, the constitutive transport element of Mason-Pfizer monkey virus can substitute for RRE and Rev at least to some extent, whereas the posttranscriptional regulatory element of human hepatitis B virus appeared to be inefficient. In addition, we show that high-titer virus preparations can be obtained in the presence of sodium butyrate, which activates the expression of both the packaging construct and the vector genome. Finally, our results suggest that efficient infectivity of vectors defective in the accessory proteins Vif, Vpr, Vpu, and Nef depends on the nature of the target cells.

CT finding of transient focal increased attenuation of the liver adjacent to the gallbladder in acute cholecystitis

OBJECTIVE

The purpose of this article is to report the finding of transient focal increased attenuation of the liver adjacent to the gallbladder on enhanced CT scans in patients with acute cholecystitis. This finding should not be confused with primary liver abnormalities.

MATERIALS AND METHODS

Five patients with acute cholecystitis were studied. Because a thickened gallbladder wall was seen on sonography, all patients were examined preoperatively with incremental dynamic helical CT to exclude carcinoma of the gallbladder. CT findings were compared with results of sonography for five patients, MR imaging for two patients, and surgery for five patients.

RESULTS

Transient focal increased attenuation of the liver adjacent to the gallbladder was seen in the early phase of incremental dynamic CT in five patients and extended into the medial segment anterior to the porta hepatis. The areas showing increased attenuation adjacent to the gallbladder had a curvilinear shape around the gallbladder. No hepatic masses were seen on sonograms, on MR images, or at surgery.

CONCLUSION

Transient focal increased attenuation of the liver may occur on CT scans in patients with acute cholecystitis. The increased attenuation associated with acute cholecystitis has a typical location and pattern. This finding is probably attributable to hepatic arterial hyperemia and to early venous drainage caused by the adjacent inflamed gallbladder. This finding should be differentiated from hypervascular hepatic tumors.

Infection of a yellow baboon with simian immunodeficiency virus from African green monkeys: evidence for cross-species transmission in the wild

Many African primates are known to be naturally infected with simian immunodeficiency viruses (SIVs), but only a fraction of these viruses has been molecularly characterized. One primate species for which only serological evidence of SIV infection has been reported is the yellow baboon (Papio hamadryas cynocephalus). Two wild-living baboons with strong SIVAGM seroreactivity were previously identified in a Tanzanian national park where baboons and African green monkeys shared the same habitat (T. Kodama, D. P. Silva, M. D. Daniel, J. E. Phillips-Conroy, C. J. Jolly, J. Rogers, and R. C. Desrosiers, AIDS Res. Hum. Retroviruses 5:337-343, 1989). To determine the genetic identity of the viruses infecting these animals, we used PCR to examine SIV sequences directly in uncultured leukocyte DNA. Targeting two different, nonoverlapping genomic regions, we amplified and sequenced a 673-bp gag gene fragment and a 908-bp env gene fragment from one of the two baboons. Phylo-genetic analyses revealed that this baboon was infected with an SIVAGM strain of the vervet subtype. These results provide the first direct evidence for simian-to-simian cross-species transmission of SIV in the wild.

Mosaic genome structure of simian immunodeficiency virus from west African green monkeys

Elucidation of the phylogenetic origins of simian and human immunodeficiency viruses (SIV and HIV) is fundamental to the understanding of HIV pathogenesis and the spread of AIDS worldwide. In this study, we molecularly characterized multiple SIVAGM isolates from four different African green monkey species (vervet, grivet, sabaeus and tantalus monkeys). Phylogenetic analysis of partial (1 kb) env sequences indicated that all SIVAGM strains cluster together, and that they fall into four distinct sequence sub-groups according to their species of origin. However, alignment of long terminal repeat sequences revealed that SIVs from West African sabaeus monkeys contain a structural feature (a duplication of the transactivation response element) thus far only found in otherwise highly divergent lentiviruses infecting sooty mangabeys (SIVSM) and humans (HIV-2). To determine whether there were additional similarities with the SIVSM/HIV-2 group, a full-length replication competent sabaeus provirus was cloned and sequenced. In phylogenetic trees derived from the central and 3' coding regions, the sabaeus virus clustered with SIVAGM isolates from other African green monkey species. However, in trees derived from the 3' half of gag and the adjacent 5' region of pol, the sabaeus virus grouped with the SIVSM/HIV-2 lineage. These results indicated that the sabaeus virus comprised a mosaic genome which must have resulted from recombination of divergent lentiviruses in the distant past. A second, independent sabaeus isolate exhibited similar phylogenetic relationships, suggesting that all West African green monkey viruses share this complex evolutionary history. Taken together, these results indicate that African green monkeys have been infected with SIVAGM for very long periods of time, and that recombination and cross-species transmission in the wild have contributed to the genetic complexity of primate lentiviruses.

Localization of the FK506-binding protein, FKBP 13, to the lumen of the endoplasmic reticulum

The function of the immunophilins, FKBP 12 and FKBP 13, which are binding proteins for the immunosuppressant drug FK506 and rapamycin, remains poorly defined, although it has been suggested that immunophilins and immunophilin-like proteins may play a role in protein sorting/folding and intracellular calcium ion regulation. As a first step towards understanding the function of FKBP 13, we studied its subcellular localization by immunoblotting of well-defined subcellular fractions from a canine pancreatic homogenate and immunocytochemical analysis of an overexpressed cloned cDNA for FKBP 13. Whereas FKBP 12 fractionated entirely into the cytosol, virtually all FKBP 13 was found in the rough microsomal fraction which consisted of highly purified rough endoplasmic reticulum (ER), along with several well-characterized ER markers [the immunoglobulin heavy-chain binding protein (BiP), grp 94 and ribophorin I]. Moreover, FKBP 13 co-banded with the ER markers on isopycnic sucrose gradients. By immunofluorescence, the overexpressed cDNA for FKBP 13 in Hela cells gave an ER-staining pattern highly similar to that of known ER proteins. Addition of the ligand FK506 did not appear to alter the distribution of FKBP 13. Separation of the ER luminal contents and membrane revealed FKBP 13 to be a luminal ER protein. Since the lumen of the ER is where the folding of membrane and secreted proteins occurs, as well as a major site of intracellular calcium storage, it seems possible that FKBP 13 may be involved in one of these functions.

Cytoplasmic domain truncation enhances fusion activity by the exterior glycoprotein complex of human immunodeficiency virus type 2 in selected cell types

To investigate the glycoprotein determinants of viral cytopathology, we constructed chimeric env genes between a noncytopathic strain of human immunodeficiency virus type 2 (HIV-2), designated HIV-2/ST, and a highly fusogenic and cytopathic variant derived from this virus. Expression of the resulting chimeric glycoproteins indicated that efficient syncytium formation in the human T-cell line Sup T1 mapped to the C-terminal region of the transmembrane (TM) glycoprotein subunit. In this region, the wild-type and cytopathic ST glycoproteins differed by only four amino acids and by the presence of a premature termination codon in the cytopathic variant. Subsequent site-directed mutagenesis indicated that the cytoplasmic domain truncation was responsible for the enhanced fusion activity. This modification, however, increased the fusion activity of the glycoprotein only in Sup T1 cells (in which the ST variant arose) but not in Molt 4 clone 8 or peripheral blood mononuclear cells. These observations indicate that the length of the cytoplasmic domain of the HIV-2 glycoprotein modulates the fusion activity of the exterior glycoprotein complex in a cell-specific manner. Such adaptability appears to permit the emergence of fusogenic variants during HIV-2 passage in vitro and may also regulate viral growth or cytopathic effects in selected cell types during natural infection in vivo.