Modulation of Lactate Dehydrogenase Isozymes by Modified Base Queuine

The modified base queuine is a nutrient factor for lower and higher eukaryotes except yeast. It is synthesized in eubacteria and inserted into the wobble position of specific tRNAs (tRNA_GUN) in exchange of guanine at position 34. The tRNAs of Q family are completely modified in terminally differentiated somatic cells. However, mainly free queuine is present in embryonic and fast proliferating cells, tRNA remains Q deficient. Lactate dehydrogenase (LDH) A mRNA and LDH A protein is known to increase when cells are grown in hypoxic conditions. In the present study, the level of LDH isozymes is analyzed in different tissues of normal and cancerous (DLA) mice and the effect of queuine treatment on LDH isozyme is observed. LDH A isozyme is shown to increase in serum and liver of DLA mice. The level and activity of LDH A decreases on queuine treatment. In skeletal muscle and heart, LDH A isozyme decreases while LDH B increases in DLA mice. Queuine administration leads to change back towards normal. In case of brain, LDH A increases but LDH B decreases in DLA mice. Queuine treatment leads to decrease in A4 anaerobic isozymes of LDH. The results suggest that queuine suppresses anaerobic glycolytic pathway, which leads to tumor suppression of DLA mice.     

Correlates of Viral Richness in Bats (Order Chiroptera)

Historic and contemporary host ecology and evolutionary dynamics have profound impacts on viral diversity, virulence, and associated disease emergence. Bats have been recognized as reservoirs for several emerging viral pathogens, and are unique among mammals in their vagility, potential for long-distance dispersal, and often very large, colonial populations. We investigate the relative influences of host ecology and population genetic structure for predictions of viral richness in relevant reservoir species. We test the hypothesis that host geographic range area, distribution, population genetic structure, migratory behavior, International Union for Conservation of Nature and Natural Resources (IUCN) threat status, body mass, and colony size, are associated with known viral richness in bats. We analyze host traits and viral richness in a generalized linear regression model framework, and include a correction for sampling effort and phylogeny. We find evidence that sampling effort, IUCN status, and population genetic structure correlate with observed viral species richness in bats, and that these associations are independent of phylogeny. This study is an important first step in understanding the mechanisms that promote viral richness in reservoir species, and may aid in predicting the emergence of viral zoonoses from bats.     

高原鼠兔组织中精子特异性乳酸脱氢酶的作用机理

高原鼠兔Ochotona curzoniae具有很强的高原低氧适应能力。前期研究发现,精子特异性乳酸脱氢酶(LDH-C4)在高原鼠兔体细胞中表达。为阐明LDH-C4在高原鼠兔组织中的作用机理,应用RNA干扰技术沉默高原鼠兔心肌、肝脏和脑组织中的Ldh-c基因;应用荧光定量PCR和Western Blot方法,测定Ldh-c基因在心肌、肝脏和脑组织中的表达水平;应用生物化学方法测定沉默Ldh-c基因后,心肌、肝脏和脑组织中LDH比活力、乳酸和ATP的含量。结果表明,腹腔注射腺病毒p MultiRNAi-Ldhc能极显著降低高原鼠兔组织中Ldh-c基因的表达水平,在mRNA和蛋白水平,心肌中Ldh-c基因的表达分别下降48.11%和19.27%;肝脏中Ldh-c基因的表达分别下降70.16%和25.82%;脑中Ldh-c基因的表达分别下降49.08%和25.36%。沉默Ldh-c基因表达后,高原鼠兔心肌、肝脏和脑组织中LDH比活力、乳酸和ATP的含量也显著降低,分别下降25.58%、41.94%和21.23%,28.16%、15.90%和24.66%以及16.65%、12.78%和18.50%。这些结果说明,高原鼠兔在低氧环境中,其心肌、肝脏和脑组织通过LDH-C4催化无氧糖酵解获得部分ATP,增强对低氧环境的适应能力。     

Bats (Chiroptera,Vespertillionidae) from the Cis-Urals and South Urals (Republic of Bashkortostan)

New and previously published data on the distribution of 12 bat species in the Cis-Urals and South Urals (Republic of Bashkortostan) are summarized. Data on their subspecies status are given. There is a need to clarify the taxonomic status of the pipistrelle bats Pipistrellus pipistrellus/pygmaeus. In terms of composition, the bat fauna of the Republic of Bashkortostan is a variant of the Central European fauna. It was revealed that the territory in question marks the eastern limits of distribution of Nyctalus leisleri and P. pipistrellus/pygmaeus. An important feature of the territory of Bashkortostan is the presence of places of mass wintering of bats of natural origin: more than 980 karst caves used by bats not only in winter, but also during the period of activity. According to the results of captures in 14 caves, data on the frequency and relative abundance of sedentary bat species in the Republic of Bashkortostan are given.     

Lactate Dehydrogenase Isozymes, Gytochrome Oxidase Activity, and Muscle Ions of the Rattail (Coryphaenoides sp.)

SYNOPSIS. Investigations into the behavior of molecules in organismsoccupying unique environments may provide a better insight intothe functions of these same molecules in organisms from morecommon habitats. An organism well suited for such analyses isthe rattail (Coryphaenoides sp.), a deep-sea teleost. The photoreceptorcells of the retina are predominantly rods. Although the lactatedehydrogenase A₁, and B₄, isozymes are present in this fish,the E₄ isozyme (found in the retina of many teleosts) is absentin the rattail retina. The rattails possess a lower cytochromeoxidase activity than shallow water fish. The sodium concentrationis higher, and the potassium concentration lower in the rattailas compared with surface marine fish. The patterns of molecularsynthesis and concentrations in the rattail may be related tosuch factors as light intensity, hydrostatic pressure, and temperaturewhich exists in the deep-sea environment.     

Different Functional and Structural Properties of Lactate Dehydrogenase Isozymes at Different Stages of Danio rerioOntogenesis

We studied properties of lactate dehydrogenase isozymes expressed at different stages of Danio rerioontogenesis. H₄-LDH and a minor fraction H₃M₁are expressed during embryonic development. The muscle isozyme (₄) appears after the beginning of muscle contractions in the embryo. ₄and ₄isozymes isolated from the heart and skeletal muscle of the adult fish, respectively, show significant differences in terms of Michaelis constant (K _m) activation energy (AE), and inactivation temperature. H₄-LDH isozymes isolated from unfertilized eggs, the skeletal muscle of larvae, and the heart of the adult fish differ inK _mand activation energy, as well as in inactivation temperature. We propose that these differences may be associated with a ligand interacting with the H₄isozyme at different steps of ontogenesis.     

Contribution to the Ectoparasite Fauna of Bats (Chiroptera: Vespertilionidae,Rhinolophidae) of Crimea

New data are presented on the ectoparasite fauna of several species of vesper and horseshoe bats (Chiroptera: Vespertilionidae, Rhinolophidae) of the Crimean Peninsula. In the studied territory, 11 species of ectoparasites (mites and insects) have been collected from 6 bat species; 2 of the ectoparasite species were new to Crimea. Findings of gamasid mites Ichoronyssus scutatus on an unusual host are discussed. The gamasid mite Spinturnix emarginatus (Acari: Mesostigmata: Gamasina) is described for the territory of Russia for the first time.     

Quaternary Climate Change was Not an Engine of Diversification in New World Bats (Chiroptera)

Quaternary climate change has been hypothesized to have played a significant role in driving diversification rates in a variety of taxa. We test the hypothesis of increased rates of diversification during the Quaternary in nine groups of New World bats (Chiroptera). The fit of six models of diversification was determined for each group. None experienced an increase in net diversification, rejecting the Quaternary hypothesis. Instead, four groups experienced constant net diversification rates, suggesting no Quaternary climate change impact. Five groups are evolving under a density-dependent model of diversification, suggesting climate cycles may have reduced rates initiated during the Pliocene or late Miocene. The distribution of divergences between sister taxa is consistent with results obtained from avian lineages experiencing declining rates of Quaternary diversification, further discrediting this often invoked hypothesis. Our results suggest that Quaternary climate change did not increase diversification rates in New World bats.     

Phylogenetic Analysis of Vertebrate Lactate Dehydrogenase (LDH) Multigene Families

In this paper we analyzed 49 lactate dehydrogenase (LDH) sequences, mostly from vertebrates. The amino acid sequence differences were found to be larger for a human–killifish pair than a human–lamprey pair. This indicates that some protein sequence convergence may occur and reduce the sequence differences in distantly related species. We also examined transitions and transversions separately for several species pairs and found that the transitions tend to be saturated in the distantly related species pair, while transversions are increasing. We conclude that transversions maintain a conservative rate through the evolutionary time. Kimura's two-parameter model for multiple-hit correction on transversions only was used to derive a distance measure and then construct a neighbor-joining (NJ) tree. Three findings were revealed from the NJ tree: (i) the branching order of the tree is consistent with the common branch pattern of major vertebrates; (ii) Ldh-A and Ldh-B genes were duplicated near the origin of vertebrates; and (iii) Ldh-C and Ldh-A in mammals were produced by an independent gene duplication in early mammalian history. Furthermore, a relative rate test showed that mammalian Ldh-C evolved more rapidly than mammalian Ldh-A. Under a two-rate model, this duplication event was calibrated to be approximately 247 million years ago (mya), dating back to the Triassic period. Other gene duplication events were also discovered in Xenopus, the first duplication occurring approximately 60–70 mya in both Ldh-A and Ldh-B, followed by another recent gene duplication event, approximately 20 mya, in Ldh-B. Received: 5 October 2001 / Accepted: 24 October 2001     

Parallel and Convergent Evolution of the Dim-Light Vision Gene RH1 in Bats (Order: Chiroptera)

Rhodopsin, encoded by the gene Rhodopsin (RH1), is extremely sensitive to light, and is responsible for dim-light vision. Bats are nocturnal mammals that inhabit poor light environments. Megabats (Old-World fruit bats) generally have well-developed eyes, while microbats (insectivorous bats) have developed echolocation and in general their eyes were degraded, however, dramatic differences in the eyes, and their reliance on vision, exist in this group. In this study, we examined the rod opsin gene (RH1), and compared its evolution to that of two cone opsin genes (SWS1 and M/LWS). While phylogenetic reconstruction with the cone opsin genes SWS1 and M/LWS generated a species tree in accord with expectations, the RH1 gene tree united Pteropodidae (Old-World fruit bats) and Yangochiroptera, with very high bootstrap values, suggesting the possibility of convergent evolution. The hypothesis of convergent evolution was further supported when nonsynonymous sites or amino acid sequences were used to construct phylogenies. Reconstructed RH1 sequences at internal nodes of the bat species phylogeny showed that: (1) Old-World fruit bats share an amino acid change (S270G) with the tomb bat; (2) Miniopterus share two amino acid changes (V104I, M183L) with Rhinolophoidea; (3) the amino acid replacement I123V occurred independently on four branches, and the replacements L99M, L266V and I286V occurred each on two branches. The multiple parallel amino acid replacements that occurred in the evolution of bat RH1 suggest the possibility of multiple convergences of their ecological specialization (i.e., various photic environments) during adaptation for the nocturnal lifestyle, and suggest that further attention is needed on the study of the ecology and behavior of bats.     

Isozyme Patterns of Lactate Dehydrogenase from Tissues of Mink and Arctic Fox during Postnatal Development

Isozymes of lactate dehydrogenase extracted from heart, kidney, and liver of mink (Mustela vison Briss.) and Arctic fox (Alopex lagopus L.) during postnatal development were separated by agarose gel electrophoresis. Tissue-specific isozyme pattern of lactate dehydrogenase can be revealed at the age of one month, while the definitive pattern is formed at the age of four months. The isozyme patterns of lactate dehydrogenase in the studied tissues of mink and Arctic fox share the properties specific for animal species of various ecogenesis.     

Palate Variation and Evolution in New World Leaf-Nosed and Old World Fruit Bats (Order Chiroptera)

Two bat families, the leaf-nosed (Phyllostomidae) and fruit bats (Pteropodidae), have independently evolved the ability to consume plant resources. However, despite their similar ages, species richness and the strong selective pressures placed on the evolution of skull shape by plant-based foods, phyllostomids display more craniofacial diversity than pteropodids. In this study, we used morphometrics to investigate the distribution of palate variation and the evolution of palate diversity in these groups. We focused on the palate because evolutionary alterations in palate morphology are thought to underlie much feeding specialization in bats. We hypothesize that the distribution of palate variation differs in phyllostomids and pteropodids, and that the rate of palate evolution is higher in phyllostomids than pteropodids. The results suggest that the overall level of palate integration is higher in adult populations of pteropodids than phyllostomids but that the distribution of palate variation is otherwise generally conserved among phyllostomids and pteropodids. Furthermore, the results are consistent with these differences in palate integration likely having a developmental basis. The results also suggest that palate evolution has occurred significantly more rapidly in phyllostomids than pteropodids. These findings are consistent with a scenario in which the greater integration of the pteropodid palate has limited its evolvability.     

Nonlinear Distribution Pattern of Hibernating Bats in Caves along an Elevational Gradient in Mountain (Carpathians,Southern Poland)

Background

Thermal gradients along changes in elevation in mountainous environments are reflected by different biotas. Although there have been studies of elevation variation in bat assemblages in summer, winter changes in the same gradients remain unknown.

Methodology/Principal Findings

The objective of this study was to document changes in the species composition of bats hibernating in caves along a temperate elevational gradient. We studied 70 caves between from 300 m to 1,930 m altitude along a slope of the Carpathian Mountains in southern Poland. We recorded changes in bats, including species richness, abundance, altitudinal distribution and dominance during consecutive winters between 2003 and 2009. Similarity of dominance of faunal structure was assessed by using the Bray-Curtis similarity index. We used the generalised additive model and rarefaction to study the variation in species richness, and generalized additive mixed models to examine the effect of abiotic factors on the qualitative and quantitative structure of bat assemblages. During 351 surveys we recorded 13,856 hibernating bats from 15 species. Species richness peaked around mid-elevation (1,100–1,400 m a.s.l.) with richness declining at both higher and lower elevations. Based on the results of a cluster analysis, we could distinguish among four altitudinal zones that differed in species richness and dominance structure.

Conclusions/Significance

This is the first study documenting changes in species richness and variation of structure of bats hibernating in caves along an elevational gradient. The most surprising and key finding is the fact that changes in the structure of assemblages of hibernating bats along the altitudinal gradient occurred in jumps, forming zones similar to those observed in the vegetation zones. Moreover, species richness and dominance structure of assemblages of hibernating bats in the mountains depended not only on location above sea level, but also on local geomorphologic conditions which strongly affected the microclimate of the caves.     

Minimal Functional Unit of Lactate Dehydrogenase

The tetrameric heart isozyme of lactate dehydrogenase (H₄) is modified by p-chloromercuribenzoate (PCMB) to produce the inactive tetramer and then hybridized with native tetrameric muscle isozyme (M₄). The hybrid mixture was isolated by polyacrylamide gel electrophoresis (PAGE) and then stained for enzyme activity and with Coomassie brilliant blue. Only three bands were found on the gels in either case. The hybrid enzymes as isolated by PAGE have half the specific activity of the native muscle enzyme. The electrophoresis properties of HM₃ are very similar to those of HM₃, while the electrophoresis properties of are very similar to those of H₂M₂. The above results strongly suggest that the tetramer having enzymatic activity contains at least two native subunits, and the di-subunit in the tetrameric enzyme is the minimal functional unit.     

基于部分线粒体细胞色素氧化酶亚基Ⅰ(mtCOI)DNA 序列的6种蝙蝠(翼手目:蝙蝠科)的分子系统进化关系

对贵州5种蝙蝠科蝙蝠的部分线粒体细胞色素氧化酶亚基ⅠDNA序列进行了测定,并结合从Genbank获得的爪哇伏翼的相应序列,以Pteropus dasymallus,P.scapulatus,Rousettus aegyptiacus为外群,运用贝叶斯法(Bayes-ian),最大似然法(Maximum Likelihood,ML)分析了这6种蝙蝠科蝙蝠的分子系统进化关系。结果表明:在贝叶斯,ML树中,这6种蝙蝠科的蝙蝠可分为3个分支:亚洲长翼蝠是第1个独立出来的分支;白腹管鼻蝠是继亚洲长翼蝠之后第2个分离出来的分支;第3个分支又分为两支,一支由大鼠耳蝠和小鼠耳蝠组成,另一支由南蝠和爪哇伏翼组成,支持将这4种蝙蝠同归于蝙蝠亚科的结论,从一定程度上否定了鼠耳蝠属和管鼻蝠亚科之间的姐妹类群关系,也不支持将鼠耳属提升为亚科。