Host specificity in bat ectoparasites: A natural experiment

We undertook a field study to determine patterns of specialisation of ectoparasites in cave-dwelling bats in Sri Lanka. The hypothesis tested was that strict host specificity (monoxeny) could evolve through the development of differential species preferences through association with the different host groups. Three species of cave-dwelling bats were chosen to represent a wide range of host-parasite associations (monoxeny to polyxeny), and both sympatric and allopatric roosting assemblages. Of the eight caves selected, six caves were “allopatric” roosts where two of each housed only one of the three host species examined: Rousettus leschenaulti (Pteropodidae), Rhinolophus rouxi and Hipposideros speoris (Rhinolophidae). The remaining two caves were “sympatric” roosts and housed all three host species. Thirty bats of each species were examined for ectoparasites in each cave, which resulted in a collection of nycteribiid and streblid flies, an ischnopsyllid bat flea, argasid and ixodid ticks, and mites belonging to three families. The host specificity of bat parasites showed a trend to monoxeny in which 70% of the 30 species reported were monoxenous. Odds ratios derived from χ²-tests revealed two levels of host preferences in less-specific parasites (i) the parasite was found on two host species under conditions of both host sympatry and host allopatry, with a preference for a single host in the case of host sympatry and (ii) the preference for a single host was very high, hence under conditions of host sympatry, it was confined to the preferred host only. However, under conditions of host allopatry, it utilized both hosts. There appears to be an increasing prevalence in host preferences of the parasites toward confinement to a single host species. The ecological isolation of the bat hosts and a long history of host-parasite co-existence could have contributed to an overall tendency of bat ectoparasites to become specialists, here reflected in the high percentage of monoxeny.     

Morphological and genomic characteristics of two novel halotolerant actinomycetes,Tomitella gaofuii sp. nov. and Tomitella fengzijianii sp. nov. isolated from bat faeces

Four white-pigmented, Gram-staining-positive, strictly aerobic, non-spore-forming, irregular rod-shaped bacteria were isolated from the faeces of bats collected from Guangxi autonomous region (22°20′54″N, 106°49′20″E; July 28, 2011) and Chongqing city (30°02′15″N, 107°07′4″E; September 1, 2011) of South China. The strains shared 99.3–99.9% 16S rRNA gene sequence similarity by BLAST search among them, and belonged to genus Tomitella according to 16S rRNA gene and genomic sequence-based phylogenetic/phylogenomic analyses. Strains HY172^T and HY188^T contained meso-diaminopimelic acid as the diagnostic diamino acid, and arabinose, glucose, galactose or ribose in their whole-cell hydrolysates. Besides sharing phosphatidylethanolamine, diphosphatidylglycerol and unidentified glycolipid(s) in their polar lipid profiles, additionally HY172^T had one unidentified phosphoglycolipid and three unidentified phospholipids whereas HY188^T had phosphatidyl inositol mannoside and four unidentified aminolipids. The main cellular fatty acids of strains HY172^T and HY188^T were C_16:0, C_18:0 10-methyl, C_18:1ω9c and summed feature 3. The genomic DNA G + C contents of both strains (HY172^T and HY188^T) were 70.9 %. The genus Tomitella contains 2311 core genes, and resuscitation promoting factor (rpf) genes can be found in all members of Tomitella. The digital DNA-DNA hybridization and average nucleotide identity values of the four novel strains with other members of the genus Tomitella were within the ranges of 20.1–45.2% and 74.8–91.9%, respectively, all below the respective recommended 70.0% and 95–96% cutoff point. Based on phylogenetic, chemotaxonomic and phenotypic analyses, these four strains could be classified as two novel species of the genus Tomitella, for which the names Tomitella gaofuii sp. nov. and Tomitella fengzijianii sp. nov. are proposed. The type strains are HY172^T (= CGMCC 1.18701^T = JCM 34231^T) and HY188^T (= CGMCC 1.16971^T = JCM 33467^T), respectively.     

Metagenomic analysis of viruses from bat fecal samples reveals many novel viruses in insectivorous bats in China

Increasing data indicate that bats harbor diverse viruses, some of which cause severe human diseases. In this study, sequence-independent amplification and high-throughput sequencing (Solexa) were applied to the metagenomic analysis of viruses in bat fecal samples collected from 6 locations in China. A total of 8,746,417 reads with a length of 306,124,595 bp were obtained. Among these reads, 13,541 (0.15%) had similarity to phage sequences and 9,170 (0.1%) had similarity to eukaryotic virus sequences. A total of 129 assembled contigs (>100 nucleotides) were constructed and compared with GenBank: 32 contigs were related to phages, and 97 were related to eukaryotic viruses. The most frequent reads and contigs related to eukaryotic viruses were homologous to densoviruses, dicistroviruses, coronaviruses, parvoviruses, and tobamoviruses, a range that includes viruses from invertebrates, vertebrates, and plants. Most of the contigs had low identities to known viral genomic or protein sequences, suggesting that a large number of novel and genetically diverse insect viruses as well as putative mammalian viruses are transmitted by bats in China. This study provides the first preliminary understanding of the virome of some bat populations in China, which may guide the discovery and isolation of novel viruses in the future.     

广东省蝙蝠新纪录——大黑伏翼

<正>广东南岭地区蝙蝠多样性较为丰富,2000年后发表的9种广东蝙蝠新纪录中即有5种采集于南岭(吴毅等,2001,2005;张燕均等,2010;周全等,2011,2012;陈毅等,2013)。2013年7月21日,我们在保护区动物资源调查过程中,于广东南岭国家级自然保护区八宝山保护站(北纬24°55'43.4″,东经113°0'57.0″,海拔1 000 m)附近的路上夜晚挂网捕捉到一批蝙蝠     

Discovery and genomic characterization of a novel bat sapovirus with unusual genomic features and phylogenetic position

Sapovirus is a genus of caliciviruses that are known to cause enteric disease in humans and animals. There is considerable genetic diversity among the sapoviruses, which are classified into different genogroups based on phylogenetic analysis of the full-length capsid protein sequence. While several mammalian species, including humans, pigs, minks, and dogs, have been identified as animal hosts for sapoviruses, there were no reports of sapoviruses in bats in spite of their biological diversity. In this report, we present the results of a targeted surveillance study in different bat species in Hong Kong. Five of the 321 specimens from the bat species, Hipposideros pomona, were found to be positive for sapoviruses by RT-PCR. Complete or nearly full-length genome sequences of approximately 7.7 kb in length were obtained for three strains, which showed similar organization of the genome compared to other sapoviruses. Interestingly, they possess many genomic features atypical of most sapoviruses, like high G+C content and minimal CpG suppression. Phylogenetic analysis of the viral proteins suggested that the bat sapovirus descended from an ancestral sapovirus lineage and is most closely related to the porcine sapoviruses. Codon usage analysis showed that the bat sapovirus genome has greater codon usage bias relative to other sapovirus genomes. In summary, we report the discovery and genomic characterization of the first bat calicivirus, which appears to have evolved under different conditions after early divergence from other sapovirus lineages.     

Corticofugal regulation of auditory sensitivity in the bat inferior colliculus

Under free-field stimulation conditions, corticofugal regulation of auditory sensitivity of neurons in the central nucleus of the inferior colliculus of the big brown bat, Eptesicus fuscus, was studied by blocking activities of auditory cortical neurons with Lidocaine or by electrical stimulation in auditory cortical neuron recording sites. The corticocollicular pathway regulated the number of impulses, the auditory spatial response areas and the frequency-tuning curves of inferior colliculus neurons through facilitation or inhibition. Corticofugal regulation was most effective at low sound intensity and was dependent upon the time interval between acoustic and electrical stimuli. At optimal interstimulus intervals, inferior colliculus neurons had the smallest number of impulses and the longest response latency during corticofugal inhibition. The opposite effects were observed during corticofugal facilitation. Corticofugal inhibitory latency was longer than corticofugal facilitatory latency. Iontophoretic application of γ-aminobutyric acid and bicuculline to inferior colliculus recording sites produced effects similar to what were observed during corticofugal inhibition and facilitation. We suggest that corticofugal regulation of central auditory sensitivity can provide an animal with a mechanism to regulate acoustic signal processing in the ascending auditory pathway. Accepted: 15 July 1998     

Purification and characterization of recombinant human respiratory syncytial virus nonstructural protein NS1

We report here the first biochemical and structural characterization of the respiratory syncytial virus (RSV) NS1 protein. We have used a pET-ubiquitin expression system to produce respiratory syncytial virus (RSV) NS1 protein in E. coli that contains a hexahistidine-tag on either the amino- or carboxyl-terminus (His(6)-NS1 and NS1-His(6), respectively). We have been able to isolate milligram quantities of highly purified His(6)-NS1 and NS1-His(6) by nickel affinity chromatography. Generation of recombinant RSV indicated that addition of the hexahistidine tag to the C-terminus of NS1 slightly decreased viral replication competence whereas addition of the tag to the N-terminus had no observable effect. Therefore, we performed a comprehensive biochemical and biophysical characterization on His(6)-NS1. His(6)-NS1 is monodisperse in solution as determined by dynamic light scattering analysis. Both gel filtration and analytical ultracentrifugation showed that His(6)-NS1 is predominantly a monomer. In agreement with theoretical predictions, circular dichroism spectroscopy showed that His(6)-NS1 contains 21% alpha-helices, 34% beta-sheets, and 45% undefined structure. Immunization with purified His(6)-NS1 generated an antiserum that specifically recognizes NS1 by immunoprecipitation from HEp-2 cells infected by RSV, indicating that His(6)-NS1 resembles native NS1. The availability of purified RSV NS1 will permit biochemical and structural investigations providing insight into the function of NS1 in viral replication and interferon antagonism.     

Auditory properties of the superior colliculus in the horseshoe bat,Rhinolophus rouxi

Summary Auditory response properties were studied in the superior colliculus (SC) of the echolocating horseshoe bat Rhinolophus rouxi, a long CF-FM bat, by the use of stationary, dichotic stimuli.The most striking finding in the horseshoe bat was an enormous overrepresentation of neurons with best frequencies in the range of the constant frequency component of the species specific echolocation call (72% of the auditory neurons). These neurons had response thresholds as low as 0 dB SPL and were narrowly tuned with Q_{10 dB} — values up to 400, just as in the nuclei of the primary auditory pathway in this species. This overrepresentation may suggest the importance of the superior colliculus in the context of echolocation behavior.While noise stimuli were not particularly effective, other auditory response properties were similar to those described in other mammals. 65% of the SC neurons in the horseshoe bat responded only to monaural stimulation of one ear, primarily the contralateral one. 32% of the neurons received monaural input from both ears. The proportion of neurons responsive to ipsilateral stimulation (41%) was rather high. Mean response latency was 8.9 ms for contralateral stimulation.A tonotopic organization is lacking, but high-frequency neurons are less frequent in rostral SC.Abbreviations CF constant frequency component of echolocation call; - >CF frequencies above range of CF-component - FM frequency modulated component of echolocation call - <FM frequencies below range of FM-component - RF resting frequency of an individual bat - Rh.r. Rhinolophus rouxi - SC superior colliculus     

Identification,classification, and functional characterization of novel sponge-associated acidimicrobiial species

Sponges are known to harbour an exceptional diversity of uncultured microorganisms, including members of the phylum Actinobacteriota. While members of the actinobacteriotal class Actinomycetia have been studied intensively due to their potential for secondary metabolite production, the sister class of Acidimicrobiia is often more abundant in sponges. However, the taxonomy, functions, and ecological roles of sponge-associated Acidimicrobiia are largely unknown. Here, we reconstructed and characterized 22 metagenome-assembled genomes (MAGs) of Acidimicrobiia from three sponge species. These MAGs represented six novel species, belonging to five genera, four families, and two orders, which are all uncharacterized (except the order Acidimicrobiales) and for which we propose nomenclature. These six uncultured species have either only been found in sponges and/or corals and have varying degrees of specificity to their host species. Functional gene profiling indicated that these six species shared a similar potential to non-symbiotic Acidimicrobiia with respect to amino acid biosynthesis and utilization of sulfur compounds. However, sponge-associated Acidimicrobiia differed from their non-symbiotic counterparts by relying predominantly on organic rather than inorganic sources of energy, and their predicted capacity to synthesise bioactive compounds or their precursors implicated in host defence. Additionally, the species possess the genetic capacity to degrade aromatic compounds that are frequently found in sponges. The novel Acidimicrobiia may also potentially mediate host development by modulating Hedgehog signalling and by the production of serotonin, which can affect host body contractions and digestion. These results highlight unique genomic and metabolic features of six new acidimicrobiial species that potentially support a sponge-associated lifestyle.     

Origin of the golgi complex in germ cells in the developing ovary of the bat

Summary Dense lamellar bodies (DLB) were noted in immature cells in the developing ovary of the free-tailed bat. The DLB appear to be formed in the nucleus. They pass through the nuclear membrane into the cytoplasm. There they give rise to parallel stacks of flattened cisternae which are representative of typical dictyosomes. During the first meiotic prophase the dictyosomes aggregate to form the Golgi complex.This study was supported in part by a research grant from U.S.P.H.S. (GRS 5 SO1 RR 05704-01).The authors wish to acknowledge the technical assistance of Mrs. Edna Burgess.     

Functional characterization and taxonomic classification of novel gammaproteobacterial diversity in sponges

Sponges harbour exceptionally diverse microbial communities, whose members are largely uncultured. The class Gammaproteobacteria often dominates the microbial communities of various sponge species, but most of its diversity remains functional and taxonomically uncharacterised. Here we reconstructed and characterised 32 metagenome-assembled genomes (MAGs) derived from three sponge species. These MAGs represent ten novel species and belong to seven orders, of which one is new. We propose nomenclature for all these taxa. These new species comprise sponge-specific bacteria with varying levels of host specificity. Functional gene profiling highlights significant differences in metabolic capabilities across the ten species, though each also often exhibited a large degree of metabolic diversity involving various nitrogen- and sulfur-based compounds. The genomic features of the ten species suggest they have evolved to form symbiotic interaction with their hosts or are well-adapted to survive within the sponge environment. These Gammaproteobacteria are proposed to scavenge substrates from the host environment, including metabolites or cellular components of the sponge. Their diverse metabolic capabilities may allow for efficient cycling of organic matter in the sponge environment, potentially to the benefit of the host and other symbionts.     

广东省发现长指鼠耳蝠及其回声定位声波特征

2013年7月在广东南岭国家级自然保护区阳山县境内(24°48′39.5′′N,112°51′01.3′′E,海拔155 m)捕捉到4只雄性蝙蝠,体型小,前臂长34.1~34.7 mm,颅全长14.3~14.7 mm;体毛浓密,背毛毛基黑色,毛尖灰色,腹毛黑或棕色,毛尖奶油白,靠近肛门处腹毛浅灰色,些许白色;翼膜附着于跖部末端;后足特别延展,长度超过胫骨长之半;鉴定为长指鼠耳蝠[Myotis longipes(Dobson1873)]。同时,基于Cyt b基因序列(1 140 bp)构建的部分鼠耳蝠物种系统进化关系,进一步确认上述标本为长指鼠耳蝠,为广东省翼手目新纪录。该种蝙蝠在我国贵州、广西、重庆有分布记载,但标本和相关资料很少。本文给出了长指鼠耳蝠的外形和头骨特征测量数据,并与印度的标本进行了对比。长指鼠耳蝠的回声定位声波为调频型(FM),主频率为68.2 k Hz;此外,对其分类地位和分布状况进行了讨论。标本保存于广东省生物资源应用研究所。     

Discovery of the Jehol Biota from the Celaomiao region and discussion of the Lower Cretaceous of the Bayingebi Basin,northwestern China

Some typical components of the Jehol Biota, including conchostracans Eosestheria sp., the mayfly Ephemeropsis trisetalis Eichwald, 1864, the aquatic beetle Coptoclava longipoda Ping, 1928, and a fragmentary dragonfly, are reported for the first time from the Bayingebi Formation in the Celaomiao region, western Inner Mongolia, China. This discovery indicates that the middle Upper Member of Bayingebi Formation can be correlated with the upper Yixian and the lower Jiufotang formations in western Liaoning Province. Combining it with the radio-isotopic dating result, we further believed that the Upper Member of Bayingebi Formation could be roughly correlated with the Yixian, Jiufotang, and Shahai formations, and the overlying Suhongtu Formation with the Fuxin Formation in western Liaoning Province.In the major Bayingebi Basin, palaeontological and radio-isotopic dating evidence shows that the Bayingebi Formation has a long depositional history of over 30 Ma: its Upper Member bearing the Jehol Biota and the early Fuxin Biota is probably coeval to the Yixian, Jiufotang and Shahai formations and has a Barremian–early Albian age; its Lower Member may be Berriasian–Hauterivian in age and could be correlated with the upper Tuchengzi, Zhangjiakou, and Dabeigou formations in northern Hebei Province. This suggests that the Bayingebi Formation should be promoted to the stratigraphic rank of group and subdivided into several secondary units (formations). Unlike the previous result, the Yingen Formation is considered across the Lower Cretaceous–Upper Cretaceous boundary and being late Albian–early Turonian in age.     

塔格糖-4-异构酶的新酶挖掘及酶学性质研究

d-塔格糖是一种己酮糖,在自然界中天然存在但含量极少,具有降血糖、抗龋齿、改善肠道菌群、促进血液循环和抗衰等作用,可广泛应用于食品、医药和化妆品行业。目前酶催化半乳糖生成塔格糖仅需一步反应,简单易行,但半乳糖较高的成本限制了这一方法的工业应用。果糖是塔格糖的同分异构体,价格低廉,来源稳定,可通过4位差向异构化一步获得塔格糖,是产塔格糖的理想底物。【目的】因此挖掘新的塔格糖-4-差向异构酶对塔格糖的工业生产具有重要意义。【方法】本文通过基因挖掘的手段发现了热袍菌(Thermotogae bacterium)来源的未知功能蛋白(命名为HCZ0)具有塔格糖-4-差向异构酶活性,进而完成了HCZ0的异源表达、纯化及酶学性质表征。【结果】确定HCZ0表观分子量约为57.9 kDa,比活力为0.9 U/mg,最适反应温度和pH值分别为70 ℃和9.0,最适金属离子为Ni²⁺,最适金属离子浓度为2 mmol/L,60、70和80 ℃半衰期分别为180、67和9 h。最适条件下,HCZ0催化200 g/L果糖在2 h内可产生28 g/L塔格糖。【结论】本研究中,HCZ0是碱性高温酶,且具有较好的热稳定性,这些特征在以后的理论研究及工业生产中具有一定的科学价值。     

Temperature dependence of capacitation in bat sperm monitored by zona-free hamster ova

The temperature dependence of capacitation in bat sperm (Myotis lucifugus lucifugus) was studied by monitoring fertilizations rates of zona-free hamster ova at different temperatures. Spermatozoa were cultured in BWW medium at temperatures 4°C, 24°C, 32°C, 42°C, and 55°C from 0–24 hr. Activation of sperm could be determined visually due to the change in movement seen through light microscopy. Activation was later confirmed by higher rates of fertilization. Preincubation of the bat sperm was found to have a direct effect on the success of penetration of the zona-free hamster ova. Holding bat spermatozoa at low temperature for long intervals allowed them to remain motile but unable to fertilize. Sperm are not irreversibly damaged, however, and activation, when the temperature is increased to 32°C, is faster than when sperm are intitially put at 32°C, resulting in good fertilization rates.     

香港大蹄蝠出飞时间及其季节变化

于2014年5月至2015年4月,对香港低海拔栖息地的大蹄蝠夜晚出飞活动时间进行了研究。结果显示大蹄蝠出飞时间平均为日落后（14.6±6.1) min,出飞时间与民用曙暮光呈强正相关（r = 0.968, P < 0.0001）,而出飞结束时刻同样与民用曙暮光时间呈现显着相关(r = 0. 977, P < 0. 0001)。。在一年中较冷的12月和1月则没有蝙蝠出飞记录。大蹄蝠虽然在亚洲分布广泛,但是相对于温带地区的蝙蝠物种来说, 关于该物种的基础生态学研究较少。本文对大蹄蝠的季节性出飞行为所开展研究工作,以利有关长远保育的深入研究。     

Changes in the fine structure of the testicular Leydig cells of the seasonally-breeding bat,Myotis adversus

Summary Leydig cells of the bat, Myotis adversus, have been examined by electron microscopy throughout fourteen months. During the breeding season the Leydig cells become hypertrophied and are characterised by prominent areas of agranular endoplasmic reticulum and numerous small, membrane-bound granules. Microperoxisomes are also observed. During the period of testicular regression. Leydig cell size and the number of membrane-bound granules are greatly reduced. Lipid droplets and dense bodies are more numerous.     

大蹄蝠头骨形态地理变化

本文采用几何形态测量法对中国大蹄蝠9个不同地理种群头骨形态变化进行研究。结果表明,不同地理种群的头骨大小及形状存在显著差异,其中云南思茅种群与海南陵水种群差异最大。回归分析表明头骨形态的地理变化与气候因素相关。随着年均温度、年均湿度的升高以及年均降水量的增多,大蹄蝠头骨变小,上颌、齿、咬肌附着部分以及耳蜗部分的形状发生变化。此外,头骨大小与海拔高度呈正相关,头骨形状变化与纬度显著相关。本研究表明对栖息地生态条件的适应是中国大蹄蝠头骨形态地理变化的重要原因。     

Genotyping of Staphylococcus aureus isolated from humans, bovine subclinical mastitis and food samples in Argentina

The aim of the present study was to characterize genotypically 45 Staphylococcus aureus strains isolated from humans, bovine subclinical mastitis and food samples in Argentina by rep-PCR and PCR amplification of virulence genes. Resistances to various antibiotics could be observed for the human S. aureus, less pronounced for the bovine strains, but not for the eight S. aureus isolated from food samples. The strains could be classified genotypically by rep-PCR and by amplification of the genes encoding protein A, coagulase, clumping factor, the collagen adhesin domains A and B, capsular polysaccharide 5 and 8, the accessory gene regulator agr classes I to III, and the S. aureus gene regulator sae. rep-PCR analyses and the different gene patterns revealed that the strains could be divided into seven groups mostly matching with the origin of the isolates. The present study describes genotypic variations of S. aureus strains isolated from different origins in Argentina. The study provides a valuable insight into molecular specificities of this important pathogen.