Cloning of oligopeptide transport carrier PepT1 and comparative analysis of PepT1 messenger ribonucleic acid expression in response to dietary nitrogen levels in yak () and indigenous cattle () on the Qinghai-Tibetan plateau

The gastrointestinal lumen can directly absorb all di- and tripeptide protein degradation products, and oligopeptide absorption depends on the specific peptide transport carriers, which are located in gastrointestinal epithelial cells on the brush border membrane. Yak () use N more efficiently than cattle do, which implies that yak have a specific mechanism of nonprotein utilization including a peptide absorption mechanism. However, this mechanism has not been clarified. Our objective was to explore whether yak possess any adaptive mechanisms of peptide absorption to survive in the harsh foraging environment of the Qinghai-Tibetan plateau. Twelve castrated males of each of 2 genotypes, yak () and indigenous cattle (), were fed diets of various N levels. The yak PepT1 (yPepT1) cDNA was cloned in omasum epithelial tissue. Our results showed that the full-length yPepT1 cDNA contains 2,805 bp, and a 2,121-bp open reading frame encodes a putative protein of 707 AA residues. The yPepT1 AA sequence identified 5 putative extracellular N-glycosylation sites (Asn, Asn, Asn, Asn, and Asn), 2 putative intracellular protein kinase A sites (Ser and Thr), and 3 intracellular putative protein kinase C sites (Ser, Ser, and Ser). The yPepT1 AA sequence was 99, 95, 86, and 83% identical to PepT1 from cattle (), sheep (), pigs (), and humans (), respectively. The relative PepT1 mRNA expression for indigenous cattle was greater than yak in the rumen, omasum, duodenum, ileum, and liver ( < 0.001); however, it was lower in jejunum tissue ( < 0.01). The relative PepT1 mRNA expression in response to increasing dietary N for both genotypes were linear in the rumen and jejunum ( < 0.10); quadratic or cubic in the reticulum ( < 0.01); linear or quadratic in the duodenum, ileum, and liver ( ≤ 0.01); and linear, quadratic, or cubic in the omasum ( < 0.001). Moreover, there were significant interactions between genotype and dietary N in rumen, reticulum, omasum, duodenum, jejunum, ileum, and liver tissues. In conclusion, the PepT1 profile and expression in gastrointestinal epithelial cells of yak varied from those of cattle, implying that yak have evolved a peptide transport mechanism to adapt the environment of the Qinghai-Tibetan plateau.

Significance of major international seaports in the distribution of murine typhus in Taiwan

Background

International seaports are hotspots for disease invasion and pathogens can persist in seaports even after ports are abandoned. Transmitted by fleas infected by Rickettsia typhi, murine typhus, a largely neglected and easily misdiagnosed disease, is known to occur primarily in large seaports. However, the significance of seaports in the occurrence of murine typhus has never been validated quantitatively.

Methodology/Principal findings

We studied the spatial distribution of murine typhus, a notifiable disease, in Taiwan. We investigated whether risk of infection was correlated with distance to international seaports and a collection of environmental and socioeconomic factors, using a Bayesian negative binomial conditionally autoregressive model, followed with geographically weighted regression. Seaports that are currently in use and those that operated in the 19^th century for trade with China, but were later abandoned due to siltation were analyzed. A total of 476 human cases of murine typhus were reported during 2000–2014 in the main island of Taiwan, with spatial clustering in districts in southwest and central-west Taiwan. A higher incidence rate (case/population) was associated with a smaller distance to currently in-use international seaports and lower rainfall and temperature, but was uncorrelated with distance to abandoned ports. Geographically weighted regression revealed a geographic heterogeneity in the importance of distance to in-use seaports near the four international seaports of Taiwan.

Conclusions/Significance

Our study suggests that murine typhus is associated with international seaports, especially for those with large trading volume. Thus, one of the costs of global trade in Taiwan might be elevated risks of murine typhus. Globalization has accelerated the spread of infectious diseases, but the burden of disease varies geographically, with regions surrounding major international seaports warranting particular surveillance.

Globalization has hastened the spread of infectious diseases, with seaports as hotspots for disease invasion. Transmitted by fleas infected with the rickettsia Rickettsia typhi, murine typhus occurs worldwide, but its significance as a common causative agent of illness in tropical regions remains largely neglected. Although it is recognized that murine typhus is prevalent primarily in large seaports, the significance of seaports in the occurrence of murine typhus has never been validated quantitatively. We thus investigated whether distribution of murine typhus in Taiwan was associated with international seaports. Notably, abandoned international seaports (abandoned in the 19^th century due to siltation) were also studied to see whether the causative agent of murine typhus might still circulate around the ports even after being abandoned. We found that infection risk of murine typhus was negatively associated with distance to operating seaports but was uncorrelated with nearness to abandoned seaports. In addition, the importance of distance to operating seaports for risk of murine typhus infection varied spatially. Our study highlights elevated disease risk as a cost of international trade and suggests particular surveillance in regions surrounding major international seaports.

[Epidemic features of dyslipidemia among Uygur, Kazakh and Han ethnic groups in Urumqi]

Objective: To analyze the epidemic features of dyslipidemia among 39 980 Uygur, Kazak and Han ethnic groups in Urumqi, and to explore the methods of prevention and treatment on dyslipidemia. Methods: The differences of blood total cholesterol (TC), triglyceride (TG), high density lipoprotein cholesterol (HDL-C), low density lipoprotein cholesterol (LDL-C) of health examination population with different ethnics, genders, and ages were compared, from 2012 to 2014 in the First Affiliated Hospital of Xinjiang Medical University. Results: Among the Uygur, Kazak and Han ethnic groups, the positive rate was respectively 35.0%, 37.0%, 30.3% in TC; 34.5%, 30.1% and 32.0% in TG; 24.9%, 18.3%, and 18.2% in HDL-C; 30.1%, 31.6% and 23.3% in LDL-C. In the same ethnic group, the abnormality rate of blood lipid in the female was lower than that of the male (P<0.001). The blood lipid abnormality rate increased significantly in those with 30-39 years, and reached the highest value in the 50-59 years group, then it decreased in those aged over 60 years (P<0.001). Conclusion: The lipid abnormality rate of the Uygur and Kazak residents was higher than that of the Han nationality, and the abnormal levels of TC and LDL-C were particularly evident in Urumqi.

Two-beam combined 3.36 J, 100 Hz diode-pumped high beam quality Nd:YAG laser system

In this paper, we develop a diode-pumped all-solid-state high-energy and high beam quality Nd:YAG laser system. A master oscillator power amplifier structure is used to provide a high pulse energy laser output with a high repetition rate. In order to decrease the amplifier working current so as to reduce the impact of the thermal effect on the beam quality, a beam splitting-amplifying-combining scheme is adopted. The energy extraction efficiency of the laser system is 50.68%. We achieve 3.36 J pulse energy at a 100 Hz repetition rate with a pulse duration of 7.1 ns, a far-field beam spot 1.71 times the diffraction limit, and 1.07% energy stability (RMS).

Surveillance of ticks and associated pathogens in free-ranging Formosan pangolins (Manis pentadactyla pentadactyla)

Chinese pangolins are critically endangered insectivorous mammals distributed in several South and Southeast Asian countries. In recent years, there has been an increase in spread of tick-borne diseases in both humans and animals worldwide. Currently, limited information is available on ticks and associated pathogens infesting pangolins. The objective of the present study was to survey ticks and associated pathogens in the Formosan pangolin population in Southeastern Taiwan. Free-ranging Formosan pangolins captured during ecological survey were examined for the presence of ticks. DNA extracted from these ticks was used to identify the tick species and also to detect the tick-borne pathogens, by molecular methods. In the present study, we found 25% (13/52) of pangolins captured during 2012-2014 infested with ixodid ticks. A total of 21 ticks were collected and 3 species were identified: Haemaphysalis hystricis (14/21), Haemaphysalis formosensis (2/21) and Amblyomma testudinarium (5/21). We detected four different tick-borne pathogens, where one was identical to Anaplasma sp. strain An.H1446 while others showed close resemblance to Rickettsia conorii subsp. caspia A-167, Ehrlichia sp. TC251-2 and Cytauxzoon spp., respectively. The present study is the first survey of ticks infesting the free-ranging Chinese pangolins and pathogens harboured by these ticks. This information is important to know the diversity of ticks and tick-borne pathogens, and its conservation significance to pangolins and other sympatric wildlife. Important future step should be regular surveillance of ticks and tick-borne diseases at human-domestic animals-wildlife interface, which can provide a useful insight into the dynamics of these pathogens and can help control and prevent outbreak of zoonoses.

A comparison of nitrogen utilization and urea metabolism between Tibetan and fine-wool sheep

To study metabolic adaptation to harsh foraging conditions, an experiment was conducted to characterize and quantify N utilization efficiency and urea metabolism in Tibetan and fine-wool sheep fed 4 levels of dietary N (11.0, 16.7, 23.1, and 29.2 g N/kg DM) in 2 concurrent 4 × 4 Latin square designs. Urea kinetics were determined using continuous intrajugular infusions of 15N15N-urea. Urinary excretions of total N and urea N increased linearly (P < 0.001) with dietary N and were not different between breeds (P ≥ 0.37). Fecal N excretion increased with dietary N for Tibetan sheep but not for fine-wool sheep (linear dietary N × breed; P < 0.05). Nitrogen retention (both amount per day and percentage of N intake) increased with increasing dietary N concentration (P < 0.001), and the rates of increase were greater in fine-wool than in Tibetan sheep (linear dietary N × breed and cubic dietary N × breed; P < 0.05). In Tibetan sheep, N retention as a percentage of intake was greatest for diets containing 16.7 g N/kg DM, whereas it was maximal for fine-wool sheep when the diet contained 23.1 g N/kg DM. Urea N entry rate, urea N recycled to the gastrointestinal tract (GIT), and urea N returned to the ornithine cycle all increased with dietary N (P < 0.05), and all were greater in Tibetan than fine-wool sheep for the 11.0 g N/kg DM diet but were greater in fine-wool than Tibetan sheep for the diet with 29.2 g N/kg DM (linear dietary N × breed; P < 0.05). Urea N excreted in feces, both amount and fraction of GIT entry rate, was less in Tibetan than fine-wool sheep for the 11.0 and 16.7 g N/kg DM diets but similar for diets with 23.1 or 29.2 g N/kg DM (linear dietary N × breed; P < 0.01). For the lowest-protein diet, the fraction of urea N production recycled to the GIT was greater in the Tibetan than fine-wool sheep (88% vs. 82%), but for the diet with 29.2 g N/kg DM it was greater for fine-wool than Tibetan sheep (46% vs. 39%; linear dietary N × breed; P < 0.05). Plasma urea N increased more rapidly in response to increasing dietary N concentration for fine-wool sheep than for Tibetan sheep (linear dietary N × breed; P < 0.05). Urea tubular load and the amount and percentage of urea reabsorbed by the kidney were greater in Tibetan than fine-wool sheep (P < 0.05). These results suggest that Tibetan sheep have mechanisms that allow them to utilize N more efficiently than the fine-wool sheep when dietary N is inadequate.

Prevalence of antibodies against Ehrlichia spp. and Orientia tsutsugamushi in small mammals around harbors in Taiwan

BACKGROUND

Tick-borne ehrlichiosis and mite-borne scrub typhus represent important emerging zoonotic rickettsial diseases. Although scrub typhus has been recognized by the Taiwanese public health system, information on ehrlichial infections is scarce in Taiwan. In this study, the risk of spread of ectoparasites on rodents through aerial and marine transportation was assessed in international and domestic harbors. Here, we report the first systematic surveillance of seroprevalence against Ehrlichia spp. in small mammals on the main island of Taiwan.

METHODS

In total, 1648 small mammals were trapped from 8 international ports, 18 domestic fishing harbors, and 7 local public health centers around Taiwan from November 2004 to December 2008. Sera were analyzed using indirect immunofluorescence assays to detect IgG antibodies against Ehrlichia chaffeensis and Orientia tsutsugamushi. A serum titer of ≧1:80 was considered positive.

RESULTS

Antibodies against Ehrlichia spp. and O. tsutsugamushi were detected in 3.28% and 4.92% of small mammals active around harbors, respectively. The seropositive rate against Ehrlichia was higher in northern Taiwan from 2005 to 2008. However, O. tsutsugamushi infections increased in southern Taiwan during this period. The serological evidence of ehrlichial and O. tsutsugamushi infections in all international ports were included in the study. No significant differences were found among the seropositive rates of Ehrlichia spp. and O. tsutsugamushi in small mammals trapped between international and local harbors.

CONCLUSIONS

The overall prevalence of Ehrlichia spp. and O. tsutsugamushi infections in small mammals active around harbors was 3.28% and 4.92%, respectively. The results provided serological evidence supporting the potential risks of transporting pathogens through air and maritime traffic. This study highlights serious issues of the emergence and spread of rickettsial diseases in Taiwan. The incidence of human ehrlichiosis requires further investigation.

Additional chromosomal abnormalities in core-binding factor acute myeloid leukemia

Despite sharing a similar genetic abnormality, patients with core binding factor acute myeloid leukemia (CBF-AML), which is characterized by the presence of t(8;21) or inv(16)/t(16;16), show heterogeneous survival. Other molecular or cytogenetic factors are supposed to have an impact on the prognosis. We enrolled 24 CBF-AML patients to determine the impact of cytogenetic abnormality, and c-KIT, FLT3, NPM1, and CEBPA mutations on the prognosis. Only three patients had the c-KIT mutation (3/24, 12.5%) and one had the FLT3 mutation. However, over half of the patients (14/24) harbored additional cytogenetic changes, including ten with loss of sexual chromosomes (LOS) [all in the t(8;21) group], and six had additional abnormalities (two cases had both LOS and additional abnormalities). From this small-number study, no association was found between c-KIT mutation and survival and relapse rate. However, additional chromosome abnormalities had a significant association with relapse of the disease (P = 0.027). Stem cell transplant had a trend of benefitting patients after relapse (P = 0.065). This implies that chromosome abnormalities occur in CBF-AML and might take part in the heterogeneous nature of CBF-AML.

Surveillance of potential hosts and vectors of scrub typhus in Taiwan

Background

Scrub typhus is a lethal infectious disease vectored by larval trombiculid mites (i.e. chiggers) infected with Orientia tsutsugamushi (OT) and recent decades have witnessed an emergence of scrub typhus in several countries. Identification of chigger species and their vertebrate hosts is fundamental for the assessment of human risks to scrub typhus under environmental changes, but intensive and extensive survey of chiggers and their hosts is still lacking in Taiwan.

Methods

Chiggers were collected from shrews and rodents in nine counties of Taiwan and were assayed for OT infections with nested polymerase chain reaction (PCR). PCR products were further sequenced to reveal probable OT strains. Rodents were assessed for OT exposure by immunofluorescent antibody assay. Lastly, incidence rate of scrub typhus in each county was associated with loads and prevalence of chigger infestations, seropositivity rate in rodents, and OT positivity rate in chiggers.

Results

Rattus losea was the most abundant (48.7 % of 1,285 individuals) and widespread (occurred in nine counties) small mammal species and hosted the majority of chiggers (76.4 % of 128,520 chiggers). Leptotrombidium deliense was the most common (64.9 % of all identified chiggers) and widespread (occurred in seven counties) chigger species but was replaced by Leptotrombidium pallidum or Leptotrombidium scutellare during the cold seasons in two counties (Matsu and Kinmen) where winter temperatures were lower than other study sites. Seropositivity rate for OT exposure in 876 assayed rodents was 43.0 % and OT positivity rate in 347 pools of chiggers was 55.9 %, with 15 OT strains identified in the 107 successfully sequenced samples. Incidence rate of scrub typhus was positively correlated with chigger loads, prevalence of chigger infestations, seropositivity rate but not OT positivity rate in chiggers.

Conclusions

Our study reveals R. losea as the primary host for chiggers and there exists a geographical and seasonal variation in chigger species in Taiwan. It also emphasizes the importance of recognition of chigger vectors and their vertebrate hosts for a better prediction of human risks to scrub typhus under rapid environmental changes.

High prevalence of Rickettsia spp. infections in small mammals in Taiwan

Surveillance for Rickettsia spp. is urgently needed due to the recent emergence of many novel rickettsioses around the globe, but previous studies in Taiwan have been limited to small areas and no investigation of infections in vertebrate hosts has ever been attempted. We surveyed rickettsial infections systematically in small-mammal hosts trapped between 2006 and 2010 throughout Taiwan. Fragments of ompB and gltA genes in the liver, spleen, and kidney of mammals were targeted by nested polymerase chain reaction. We trapped 1375 individuals of 10 species, among which Rattus losea was the most common (54.6%), followed by Suncus murinus (20.6%) and Mus caroli (10.6%). The overall rate of Rickettsia infections in the liver, spleen, or kidney of 309 assayed small mammals was 60.5%, with a rate of infection ≥50% for each mammal species. DNA nucleotide sequences of 184 successfully sequenced genes were most similar to nine Rickettsia species: Rickettsia conorii, R. felis, R. japonica, R. raoultii, R. rickettsii, Rickettsia sp. IG-1, Rickettsia sp. TwKM01, Rickettsia sp. TwKM02, and R. typhi. Our results suggest that several novel Rickettsia spp. are common and widespread across various habitats throughout Taiwan and suggest the need for further study of emerging rickettsioses in Taiwan.

A Checklist of Chigger Mites (Acari: Trombiculidae and Leeuwenhökiidae) From Taiwan, With Descriptions of Three New Species

Scrub typhus is a lethal human disease transmitted by larval trombiculid mites (i.e., chiggers) that have been infected with the rickettsia Orientia tsutsugamushi. In total, 21 chigger species are known from Taiwan. We update the checklist of chiggers of Taiwan based on an intensive survey of shrew and rodent hosts in grasslands and agricultural fields in lowland Taiwan, coupled with surveys of forests in one mountainous site and an opportunistic examination of submitted host specimens. Three new species of chiggers, Gahrliepia (Gateria) lieni sp. n., Gahrliepia (Gateria) minuta sp. n., and Gahrliepia (Gateria) yilanensis sp. n., as well as 23 newly recorded chigger species, were discovered. Accordingly, recorded chigger species of Taiwan more than doubled from 21 to 47 species. Two new species and nine newly recorded chigger species were discovered in forests in one mountainous site in northeastern Taiwan, suggesting that many more chigger species may be uncovered, particularly in mountainous Taiwan. Further studies should also investigate O. tsutsugamushi infection in different chigger species to assess its risks to human health.

Association of CRTC2 gene polymorphisms with growth and meat quality traits of Qinchuan cattle

Growth and meat quality traits play important roles in the evaluation of cattle productivity and are influenced by genetic and environmental factors. CRTC2 is a recently discovered gene related to obesity that may influence fat deposition. The aim of the current study was to detect polymorphisms of bovine CRTC2 and explore their relationships to growth and meat quality in Qinchuan cattle. Three single nucleotide polymorphisms (SNPs); g.3001 C>T; g.3034 G>A; and g.3467 T>C, were identified from sequencing results of 422 Qinchuan cattle. The genotypic distributions of both g.3034 G>A and g.3467 T>C mutations were in agreement with Hardy-Weinberg equilibrium, (P < 0.05), while the T3001C mutation was not (P > 0.05), based on χ(2) test analysis. The SNPs g.3001 C>T and g.3034 G>A are missense mutations (Ser/Phe and Ser/Thr respectively). Additionally, SNPs g.3034 G>A and g.3467 T>C showed a medium polymorphism level (0.25 < PIC< 0.50), whereas g.3001 C>T showed a low polymorphism level (PIC < 0.25). These three SNPs were significantly associated with several growth and meat quality traits in the Qinchuan cattle population (P < 0.05 or P < 0.01). Collectively, these results demonstrate that CRTC2 is involved in the regulation of cattle growth and meat quality, and suggest that CRTC2 is a potential candidate gene for marker-assisted selection in future breeding development programs for Qinchuan cattle.

Widespread Rickettsia spp. Infections in Ticks (Acari: Ixodoidea) in Taiwan

Ticks are second to mosquitoes as the most important disease vectors, and recent decades have witnessed the emergence of many novel tick-borne rickettsial diseases, but systematic surveys of ticks and tick-borne rickettsioses are generally lacking in Asia. We collected and identified ticks from small mammal hosts between 2006 and 2010 in different parts of Taiwan. Rickettsia spp. infections in ticks were identified by targeting ompB and gltA genes with nested polymerase chain reaction. In total, 2,732 ticks were collected from 1,356 small mammals. Rhipicephalus haemaphysaloides Supino (51.8% of total ticks), Haemaphysalis bandicota Hoogstraal & Kohls (28.0%), and Ixodes granulatus Supino (20.0%) were the most common tick species, and Rattus losea Swinhoe (44.7% of total ticks) and Bandicota indica Bechstein (39.9%) were the primary hosts. The average Rickettsia infective rate in 329 assayed ticks was 31.9% and eight Rickettsia spp. or closely related species were identified. This study shows that rickettsiae-infected ticks are widespread in Taiwan, with a high diversity of Rickettsia spp. circulating in the ticks. Because notifiable rickettsial diseases in Taiwan only include mite-borne scrub typhus and flea-borne murine typhus, more studies are warranted for a better understanding of the real extent of human risks to rickettsioses in Taiwan.

A case-control study on the risk factors of urinary calculus in Uyghur children in the Kashi region

The incidence of urinary calculus (UC) is very high in Uyghur children in the Kashi region of Xinjiang, China, which seriously affects the growth and life quality of these children. This study was aimed at investigating the risk factors of UC in Uyghur children in Kashi region. One hundred fifteen Uyghur children (age <7 years) with UC who were treated in First People's Hospital in Kashi were enrolled in the case group. A 1:1 case-control study with a questionnaire was performed. The results showed that, among the 115 UC patients, there were more boys (71.3%) than girls (28.7%), and most cases had an onset age of 1-3 years (75.7%). A lower than primary school education in the mother, drinking unboiled water, water intake <500 mL/day, and eating too much sweets were risk factors [odds ratio (OR) = 2.385, 9.160, 3.263, and 8.945, respectively], whereas vegetable intake and exposure to summer sunshine of <2 h/day were protective factors against UC onset (OR = 0.154 and 0.344, respectively). Analysis of UC-related factors in 99 cases of <3-year-old children revealed that breastfeeding was also a protective factor (OR = 0.007), whereas frequent cow's milk intake within 5 months (OR = 2.414) and frequent "panada" intake (OR = 2.529) were risk factors. The occurrence of UC in Uyghur children in the Kashi region is mainly affected by maternal educational background, quality of drinking water, water intake volume, and dietary pattern. Furthermore, geography may also have a role.

Polymorphisms in the SIRT5 gene and their association with body measurement and ultrasound traits in Qinchuan cattle

Silent information regulator 5 (SIRT5), a member of the Sirtuin family class III nicotinamide adenine dinucleotide-dependent protein deacetylases, plays an important role in metabolic and aging processes in mammals. We identified 4 single-nucleotide polymorphisms (SNPs) (G22010A, G22052A, G22119T, and G22245C) in the 3' untranslated regions of the SIRT5 gene from 572 Qinchuan cattle by sequencing and investigating their association with growth and ultrasound traits. The frequencies of genotype GG and allele G were high at the 4 SNPs. Based on the X(2) test, the genotypic distributions of the 4 SNPs were not in Hardy-Weinberg equilibrium (P < 0.05 or P < 0.01). Association analysis of individual SNPs and haplotype combinations revealed that the 4 loci were significantly associated with some body measurement and ultrasound traits in Qinchuan cattle, and the H1H5 (AG-GA-GG-GG) diplotypes had better performance than other combinations in Qinchuan cattle. Our results demonstrate that SIRT5 may be a candidate for marker-assisted selection in future breeding programs for Qinchuan cattle.

A simple empirical model for the clarification-thickening process in wastewater treatment plants

In wastewater treatment plants (WWTPs), activated sludge is thickened in secondary settling tanks and recycled into the biological reactor to maintain enough biomass for wastewater treatment. Accurately estimating the activated sludge concentration in the lower portion of the secondary clarifiers is of great importance for evaluating and controlling the sludge recycled ratio, ensuring smooth and efficient operation of the WWTP. By dividing the overall activated sludge-thickening curve into a hindered zone and a compression zone, an empirical model describing activated sludge thickening in the compression zone was obtained by empirical regression. This empirical model was developed through experiments conducted using sludge from five WWTPs, and validated by the measured data from a sixth WWTP, which fit the model well (R² = 0.98, p < 0.001). The model requires application of only one parameter, the sludge volume index (SVI), which is readily incorporated into routine analysis. By combining this model with the conservation of mass equation, an empirical model for compression settling was also developed. Finally, the effects of denitrification and addition of a polymer were also analysed because of their effect on sludge thickening, which can be useful for WWTP operation, e.g., improving wastewater treatment or the proper use of the polymer.

The effects of mite parasitism on the reproduction and survival of the Taiwan field mice (Apodemus semotus)

Background

The effects of parasitism on host survival and reproduction can be highly complex depending on the type of parasites, host sex and life-history characteristics, and ecological conditions. In this study, we tested sex-biased parasitism from Trombiculid mites (Acarina: Trombiculidae) and their sex-specific effects on host reproduction and survival, in a natural population of the Taiwan field mouse (Apodemus semotus). We performed surveys of A. semotus and their Trombiculid mites between April 2010 and August 2011 and again between June and September 2012 in a subtropical evergreen forest in Taiwan.

Results

Contrary to the commonly reported male-biased parasitism in mammals, we did not find sex-biased parasitism in A. semotus. We found that mite abundance was negatively associated with A. semotus reproduction and survival in both males and females. The mite abundance and rodent reproduction fluctuated seasonally, and the peak reproductive season coincided with the time period of relatively low mite abundance.

Conclusions

Trombiculid mites could potentially regulate A. semotus populations through reducing their reproduction and survival. The overlapping periods of peak reproduction and low parasitism implied that A. semotus may adjust their reproductive phenology to avoid periods of high parasitism or be constrained by parasites to reproduce only during periods of low parasitism. Although our results are correlational, host breeding season has been shown to increase in response to experimental reduction of parasitism. We suggest that parasites may shape host reproduction phenology through which they may influence host population dynamics.

Isolated familial pneumothorax in a Taiwanese family with Birt-Hogg-Dubé syndrome

Primary spontaneous pneumothorax usually occurs as a sporadic event, but may be clustered in certain families with an underlying inherited disorder. Birt-Hogg-Dubι (BHD) syndrome is a rare autosomal dominant disease accounting for familial pneumothorax. BHD syndrome, caused by mutation of the folliculin gene, is characterized by skin fibrofolliculoma, pulmonary cysts, pneumothorax, and renal cancer. We describe a BHD-affected Taiwanese family with clinical and genetic study. A rare mutation of the folliculin gene was detected in the patient and members with pulmonary cysts or pneumothorax, but no skin or renal lesions were found. This mutation was reported in a Taiwanese family and might indicate a pneumothorax-predominant phenotype. Isolated pneumothorax is an uncommon initial presentation of BHD syndrome. Family history should be carefully reviewed when managing a patient with pneumothorax.

Cladosporium cladosporioides Identified in China on Tobacco Seeds

Tobacco (Nicotiana tabacum L.) is a leafy, annual, solanaceous plant grown commercially for its leaves. China is the biggest single tobacco market and accounts for more than 40% of the global tobacco consumption (1). Tobacco seed harvested in Guiyang, Guizhou Province, China, are commonly contaminated or infected by various fungal pathogens, which can cause abnormal seedlings with dark brown lesions and stunting of roots and decayed seeds. In 2013, five samples of 500 seeds from tobacco cv. Guiyan 4 were tested for germination on moistened paper on petri dishes. On average, 35% of the seeds from all five samples developed into abnormal seedlings or were decayed and were plated onto potato dextrose agar media and grown for 5 days at 25°C in darkness to confirm the presence of a pathogen. However, one fungus was isolated from an average of 10% of the 500 seeds sampled. It was identified morphologically as Cladosporium cladosporioides (Fresen.) de Vries based on the velvety olive-brown with almost black reverse colony color and dimensions and color of conidia and conidiophores. Conidia formed in long branched chains that readily disarticulate, single celled, elliptical to limoniform, 2 to 8 (avg. 4.3) × 2 to 3 (avg. 2.1) μm. Conidia were pale to olive brown and smooth to verruculose. Ramoconidia were 0 to 1 septate, 7 to 14 (avg. 9.2) × 2 to 4 (avg. 2.6) μm, smooth or sometimes minutely verruculose. Conidiophores were pale to olive brown, macro- and micronemateus, smooth or sometimes verruculose, and of various lengths up to 320 μm long and 2 to 5 μm wide. Primer pair ITS1 and ITS4 was employed to amplify the regions of ITS1-5.8s-ITS2 of the pathogens. Sequences of all three isolates (G3, G10, and G18) (Accession Nos. KF841547, KF841554, and KF841560) were identical to each other and to four sequences in GenBank (JX230994.1, JQ768317.1, JQ768322.1, and AB763555.1). Pathogenicity of the three isolates of C. cladosporioides was verified on tobacco seedlings of 3-week-old grown on wet filter paper in the petri dishes (9 cm in diameter). For each isolate, 20 seedlings incubated in one plate were inoculated with 0.5 ml of a suspension of 10⁵ conidia/ml. Twenty seedlings were treated with sterile water as control treatment. After inoculation, the petri dishes were incubated at 25°C, 100 to 120 μEm^-2 S^-1, RH > 80%, and 16 h light per day for disease development. At 96 h after inoculation, symptoms comprising medium brown to black lesions on the roots were clearly visible on inoculated plants but not on the control plants. All seedlings inoculated died 9 days after inoculation whereas control seedlings remained symptomless. Re-isolation attempts on PDA from roots demonstrated C. cladosporioides to be present in symptomatic seedlings but not in roots of the control plants. Moreover, the characteristics of the cultured fungi were exactly the same as those originally isolated. Isolates G3, G10, and G18 (KF841547, KF841554, and KF841560) were deposited with the Tobacco Diseased Fungi, Guizhou Academy of Tobacco Sciences, Guizhou, China. Previously, C. cladosporioides has also been isolated from macadamia (Macadamia integrifolia Maiden & Betche) racemes in South Africa (4), from diseased papaya (Carica papaya L.) in Taiwan province of China (2), and from seeds of Amaranthus spp. in Poland (3). To the best of our knowledge, this is the first report of C. cladosporioides causing seed disease on tobacco in China and the disease should be considered in existing disease management practices. References: (1) British American Tobacco Annual Report, 8, 2012. (2) R. S. Chen, et al. Plant Dis. 93:426, 2009. (3) W. Pusz. Phytopathologia 54:15, 2009. (4) N. van den Berg et al. Plant Dis. 92:484, 2008.

Bayesian spatial modelling and the significance of agricultural land use to scrub typhus infection in Taiwan

Scrub typhus is transmitted by the larval stage of trombiculid mites. Environmental factors, including land cover and land use, are known to influence breeding and survival of trombiculid mites and, thus, also the spatial heterogeneity of scrub typhus risk. Here, a spatially autoregressive modelling framework was applied to scrub typhus incidence data from Taiwan, covering the period 2003 to 2011, to provide increased understanding of the spatial pattern of scrub typhus risk and the environmental and socioeconomic factors contributing to this pattern. A clear spatial pattern in scrub typhus incidence was observed within Taiwan, and incidence was found to be significantly correlated with several land cover classes, temperature, elevation, normalized difference vegetation index, rainfall, population density, average income and the proportion of the population that work in agriculture. The final multivariate regression model included statistically significant correlations between scrub typhus incidence and average income (negatively correlated), the proportion of land that contained mosaics of cropland and vegetation (positively correlated) and elevation (positively correlated). These results highlight the importance of land cover on scrub typhus incidence: mosaics of cropland and vegetation represent a transitional land cover type which can provide favourable habitats for rodents and, therefore, trombiculid mites. In Taiwan, these transitional land cover areas tend to occur in less populated and mountainous areas, following the frontier establishment and subsequent partial abandonment of agricultural cultivation, due to demographic and socioeconomic changes. Future land use policy decision-making should ensure that potential public health outcomes, such as modified risk of scrub typhus, are considered.

Elastase induced lung epithelial cell apoptosis and emphysema through placenta growth factor

Chronic pulmonary obstructive disease (COPD) is the fourth leading cause of death worldwide, however, the pathogenic factors and mechanisms are not fully understood. Pulmonary emphysema is one of the major components of COPD and is thought to result from oxidative stress, chronic inflammation, protease–antiprotease imbalance and lung epithelial (LE) cell apoptosis. In our previous studies, COPD patients were noted to have higher levels of placenta growth factor (PlGF) in serum and bronchoalveolar lavage fluid than controls. In addition, transgenic mice overexpressing PlGF developed pulmonary emphysema and exposure to PlGF in LE cells induced apoptosis. Furthermore, intratracheal instillation of porcine pancreatic elastase (PPE) on to PlGF wild type mice induced emphysema, but not in PlGF knockout mice. Therefore, we hypothesized that PPE generates pulmonary emphysema through the upregulation of PlGF expression in LE cells. The elevation of PlGF then leads to LE cell apoptosis. In the present study, we investigated whether PPE induces PlGF expression, whether PlGF induces apoptosis and whether the downstream mechanisms of PlGF are related to LE cell apoptosis. We found that PPE increased PlGF secretion and expression both in vivo and in vitro. Moreover, PlGF-induced LE cell apoptosis and PPE-induced emphysema in the mice were mediated by c-Jun N-terminal kinase (JNK) and p38 mitogen-activated protein kinase (p38 MAPK) pathways. Given these findings, we suggest that the increase in PlGF and PlGF-induced JNK and p38 MAPK pathways contribute to PPE-induced LE cell apoptosis and emphysema. Regulatory control of PlGF and agents against its downstream signals may be potential therapeutic targets for COPD.

Cascading effect of economic globalization on human risks of scrub typhus and tick-borne rickettsial diseases

The increase in global travel and trade has facilitated the dissemination of disease vectors. Globalization can also indirectly affect vector-borne diseases through the liberalization of cross-border trade, which has far-reaching, worldwide effects on agricultural practices and may in turn influence vectors through the modification of the ecological landscape. While the cascading effect of economic globalization on vector-borne diseases, sometimes acting synergistically with regional agricultural policy, could be substantial and have significant economic, agricultural, and public health implications, research into this remains very limited. We evaluated how abandonment of rice paddies in Taiwan after joining the World Trade Organization, along with periodic plowing, an agricultural policy to reduce farm pests in abandoned fields can unexpectedly influence risks to diseases transmitted by ticks and chiggers (larval trombiculid mites), which we collected from their small-mammal hosts. Sampling was limited to abandoned (fallow) and plowed fields due to the challenge of trapping small mammals in flooded rice paddies. Striped field mice (Apodemus agrarius) are the main hosts for both vectors. They harbored six times more ticks and three times more chiggers in fallow than in plowed plots. The proportion of ticks infected with Rickettsia spp. (etiologic agent of spotted fever) was three times higher in fallow plots, while that of Orientia tsutsugamushi (scrub typhus) in chiggers was similar in both treatments. Fallow plots had more ground cover and higher vegetation than plowed ones. Moreover, ticks and chiggers in both field types were dominated by species known to infest humans. Because ticks and chiggers should exhibit very low survival in flooded rice paddies, we propose that farm abandonment in Taiwan, driven by globalization, may have inadvertently led to increased risks of spotted fever and scrub typhus. However, periodic plowing can unintentionally mitigate vector burdens. Economic globalization can have unexpected consequences on disease risk through modification of the agricultural landscape, but the outcome may also be influenced by agricultural policies, calling for further research on vector-borne diseases and their control from broader perspectives.

Detection of Rickettsia spp. and host and habitat associations of fleas (Siphonaptera) in eastern Taiwan

Rickettsia typhi and Rickettsia felis (Rickettsiales: Rickettsiaceae) are two rickettsiae principally transmitted by fleas, but the detection of either pathogen has rarely been attempted in Taiwan. Of 2048 small mammals trapped in eastern Taiwan, Apodemus agrarius Pallas (24.5%) and Mus caroli Bonhote (24.4%) (both: Rodentia: Muridae) were the most abundant, and M. caroli hosted the highest proportion of fleas (63.9% of 330 fleas). Two flea species were identified: Stivalius aporus Jordan and Rothschild (Siphonaptera: Stivaliidae), and Acropsylla episema Rothschild (Siphonaptera: Leptopsyllidae). Nested polymerase chain reaction targeting parts of the ompB and gltA genes showed six fleas to be positive for Rickettsia spp. (3.8% of 160 samples), which showed the greatest similarity to R. felis, Rickettsia japonica, Rickettsia conorii or Rickettsia sp. TwKM01. Rickettsia typhi was not detected in the fleas and Rickettsia co-infection did not occur. Both flea species were more abundant during months with lower temperatures and less rainfall, and flea abundance on M. caroli was not related to soil hardness, vegetative height, ground cover by litter or by understory layer, or the abundance of M. caroli. Our study reveals the potential circulation of R. felis and other rickettsiae in eastern Taiwan, necessitating further surveillance of rickettsial diseases in this region. This is especially important because many novel rickettsioses are emerging worldwide.

In vitro cytotoxic activity of novel protoflavone analogs - selectivity towards a multidrug resistant cancer cell line

BACKGROUND

Protoapigenone (PA), a natural flavonoid possessing an unusual p-quinol moiety on its B ring, is a prospective novel lead compound against cancer currently in development, together with WYC0209, a potent synthetic PA analog. Structure activity relationships (SAR) concerning different 1'-O-alkyl side-chains were also studied on two sets of derivatives.

MATERIALS AND METHODS

Fifteen 1'-O-alkyl protoflavone derivatives were synthesized from genkwanin or 4'-hydroxy-6-methylflavone, thirteen of which are new compounds. All compounds were tested for their cytotoxic effect on four human cancer cell lines, such as HepG2 and Hep3B (hepatic), A549 (lung) and MDA-MB-231 (breast) cell lines, with doxorubicin as a positive control. All compounds, as well as PA, WYC0209 and fourteen of their previously reported analogs were also tested on a multidrug-resistant (MDR) sub-cell line of L5178 mouse T-cell lymphoma and on its parental counterpart (PAR).

RESULTS

In general, derivatives bearing a free hydroxyl group at C-1' exerted the strongest activities, while C-1'-substituted compounds were found to be much weaker. Derivatives of 6-methylflavone exhibited mild, but statistically significant selectivity towards the MDR cell line.

CONCLUSION

The results are in agreement with our previous findings for fundamental SAR of protoflavones. 6-Methylated protoflavones may serve as valuable leads for developing selective compounds against MDR cancer. Identical activity of other derivatives on the PAR and MDR cell lines suggests that cancer cells cannot exhibit resistance to protoflavones by ABCB1 efflux pump overexpression.