Projected impacts of climate change on snow leopard habitat in Qinghai Province,China

Assessing species’ vulnerability to climate change is a prerequisite for developing effective strategies to reduce emerging climate‐related threats. We used the maximum entropy algorithm (MaxEnt model) to assess potential changes in suitable snow leopard (Panthera uncia) habitat in Qinghai Province, China, under a mild climate change scenario. Our results showed that the area of suitable snow leopard habitat in Qinghai Province was 302,821 km² under current conditions and 228,997 km² under the 2050s climatic scenario, with a mean upward shift in elevation of 90 m. At present, nature reserves protect 38.78% of currently suitable habitat and will protect 42.56% of future suitable habitat. Current areas of climate refugia amounted to 212,341 km² and are mainly distributed in the Sanjiangyuan region, Qilian mountains, and surrounding areas. Our results provide valuable information for formulating strategies to meet future conservation challenges brought on by climate stress. We suggest that conservation efforts in Qinghai Province should focus on protecting areas of climate refugia and on maintaining or building corridors when planning for future species management.     

Recent Changes in Glacial Area and Volume on Tuanjiefeng Peak Region of Qilian Mountains,China

Glaciers'' runoff in the Qilian Mountains serves as a critical water resource in the northern sections of the Gansu province, the northeastern sections of the Qinghai province, and the northeastern fringe of the Tibetan Plateau. Changes in the glacial area and volume around the highest peak of the Qilian Mountains, i.e., Tuanjiefeng Peak, were estimated using multi-temporal remote-sensing images and digital elevation models, and all possible sources of uncertainty were considered in detail. The total glacier area decreased by 16.1±6.34 km² (9.9±3.9%) during 1966 to 2010. The average annual glacier shrinkage was −0.15% a⁻¹ from 1966 to 1995, −0.61% a⁻¹ from 1995 to 2000, −0.20% a⁻¹ from 2000 to 2006, and −0.45% a⁻¹ from 2006 to 2010. A comparison of glacier surface elevations using digital elevation models derived from topographic maps in 1966 and from the Shuttle Radar Topography Mission in 1999 suggests that 65% of the grid cells has decreased, thereby indicating that the glacier thickness has declined. The average change in glacier thickness was −7.3±1.5 m (−0.21±0.04 m·a⁻¹) from 1966 to 1999. Glaciers with northeastern aspects thinned by 8.3±1.4 m from 1966 to 1999, i.e., almost twice as much as those with southwestern aspects (4.3±1.3 m). The ice volume decreased by 11.72±2.38×10⁸ m³ from 1966 to 1999, which was about 17.4% more than the value calculated from the statistical relationship between glacier area and volume. The relationship between glacier area change and elevation zone indicates that glacier change is not only dominated by climate change but also affected by glacier dynamics, which are related to local topography. The varied response of a single glacier to climate change indicates that the glacier area change scheme used in some models must be improved.     

Biomass of scyphozoan jellyfish, and its spatial association with 0-group fish in the Barents Sea

An 0-group fish survey is conducted annually in the Barents Sea in order to estimate fish population abundance. Data on jellyfish by-catch have been recorded since 1980, although this dataset has never been analysed. In recent years, however, the ecological importance of jellyfish medusae has become widely recognized. In this paper the biomass of jellyfish (medusae) in 0–60 m depths is calculated for the period 1980–2010. During this period the climate changed from cold to warm, and changes in zooplankton and fish distribution and abundance were observed. This paper discusses the less well known ecosystem component; jellyfish medusae within the Phylum Cnidaria, and their spatial and temporal variation. The long term average was ca. 9×10⁸ kg, with some years showing biomasses in excess of 5×10⁹ kg. The biomasses were low during 1980s, increased during 1990s, and were highest in early 2000s with a subsequent decline. The bulk of the jellyfish were observed in the central parts of the Barents Sea, which is a core area for most 0-group fishes. Jellyfish were associated with haddock in the western area, with haddock and herring in the central and coastal area, and with capelin in the northern area of the Barents Sea. The jellyfish were present in the temperature interval 1°C<T<10°C, with peak densities at ca. 5.5°C, and the greatest proportion of the jellyfish occurring between 4.0–7.0°C. It seems that the ongoing warming trend may be favourable for Barents Sea jellyfish medusae; however their biomass has showed a recent moderate decline during years with record high temperatures in the Barents Sea. Jellyfish are undoubtedly an important component of the Barents Sea ecosystem, and the data presented here represent the best summary of jellyfish biomass and distribution yet published for the region.     

Change in the Green-Up Dates for Quercus mongolica in Northeast China and Its Climate-Driven Mechanism from 1962 to 2012

The currently available studies on the green-up date were mainly based on ground observations and/or satellite data, and few model simulations integrated with wide coverage satellite data have been reported at large scale over a long time period (i.e., > 30 years). In this study, we combined phenology mechanism model, long-term climate data and synoptic scale remote sensing data to investigate the change in the green-up dates for Quercus mongolica over 33 weather stations in Northeast China and its climate-driven mechanism during 1962-2012. The results indicated that the unified phenology model can be well parameterized with the satellite derived green-up dates. The optimal daily mean temperature for chilling effect was between -27°C and 1°C for Q. mongolica in Northeast China, while the optimal daily mean temperature for forcing effect was above -3°C. The green-up dates for Q. mongolica across Northeast China showed a delayed latitudinal gradient of 2.699 days degree^-1, with the earliest date on the Julian day 93 (i.e., 3^th April) in the south and the latest date on the Julian day 129 (i.e., 9^th May) in the north. The green-up date for Q. mongolica in Northeast China has advanced 6.6 days (1.3 days decade^-1) from 1962 to 2012. With the prevailing warming in autumn, winter and spring in Northeast China during the past 51 years, the chilling effect for Q. mongolica has been weakened, while the forcing effect has been enhanced. The advancing trend in the green-up dates for Q. mongolica implied that the enhanced forcing effect to accelerate green-up was stronger than the weakened chilling effect to hold back green-up while the changes of both effects were caused by the warming climate.     

Resource Requirements of the Pacific Leatherback Turtle Population

The Pacific population of leatherback sea turtles (Dermochelys coriacea) has drastically declined in the last 25 years. This decline has been linked to incidental capture by fisheries, egg and meat harvesting, and recently, to climate variability and resource limitation. Here we couple growth rates with feeding experiments and food intake functions to estimate daily energy requirements of leatherbacks throughout their development. We then estimate mortality rates from available data, enabling us to raise food intake (energy requirements) of the individual to the population level. We place energy requirements in context of available resources (i.e., gelatinous zooplankton abundance). Estimated consumption rates suggest that a single leatherback will eat upward of 1000 metric tonnes (t) of jellyfish in its lifetime (range 924–1112) with the Pacific population consuming 2.1×10⁶ t of jellyfish annually (range 1.0–3.7×10⁶) equivalent to 4.2×10⁸ megajoules (MJ) (range 2.0–7.4×10⁸). Model estimates suggest 2–7 yr-old juveniles comprise the majority of the Pacific leatherback population biomass and account for most of the jellyfish consumption (1.1×10⁶ t of jellyfish or 2.2×10⁸ MJ per year). Leatherbacks are large gelatinous zooplanktivores with consumption to biomass ratios of 96 (up to 192 if feeding strictly on low energy density Cnidarians); they, therefore, have a large capacity to impact gelatinous zooplankton landscapes. Understanding the leatherback''s needs for gelatinous zooplankton, versus the availability of these resources, can help us better assess population trends and the influence of climate induced resource limitations to reproductive output.     

Demographic Amplification of Climate Change Experienced by the Contiguous United States Population during the 20th Century

Better understanding of the changing relationship between human populations and climate is a global research priority. The 20^th century in the contiguous United States offers a particularly well-documented example of human demographic expansion during a period of radical socioeconomic and environmental change. One would expect that as human society has been transformed by technology, we would become increasingly decoupled from climate and more dependent on social infrastructure. Here we use spatially-explicit models to evaluate climatic, socio-economic and biophysical correlates of demographic change in the contiguous United States between 1900 and 2000. Climate-correlated variation in population growth has caused the U.S. population to shift its realized climate niche from cool, seasonal climates to warm, aseasonal climates. As a result, the average annual temperature experienced by U.S. citizens between 1920 and 2000 has increased by more than 1.5°C and the temperature seasonality has decreased by 1.1°C during a century when climate change accounted for only a 0.24°C increase in average annual temperature and a 0.15°C decrease in temperature seasonality. Thus, despite advancing technology, climate-correlated demographics continue to be a major feature of contemporary U.S. society. Unfortunately, these demographic patterns are contributing to a substantial warming of the climate niche during a period of rapid environmental warming, making an already bad situation worse.     

Isolation,cDNA Cloning,and Structure-based Functional Characterization of Oryctin,a Hemolymph Protein from the Coconut Rhinoceros Beetle,Oryctes rhinoceros,as a Novel Serine Protease Inhibitor

We isolated oryctin, a 66-residue peptide, from the hemolymph of the coconut rhinoceros beetle Oryctes rhinoceros and cloned its cDNA. Oryctin is dissimilar to any other known peptides in amino acid sequence, and its function has been unknown. To reveal that function, we determined the solution structure of recombinant ¹³C,¹⁵N-labeled oryctin by heteronuclear NMR spectroscopy. Oryctin exhibits a fold similar to that of Kazal-type serine protease inhibitors but has a unique additional C-terminal α-helix. We performed protease inhibition assays of oryctin against several bacterial and eukaryotic proteases. Oryctin does inhibit the following serine proteases: α-chymotrypsin, endopeptidase K, subtilisin Carlsberg, and leukocyte elastase, with K_i values of 3.9 × 10⁻¹⁰ m, 6.2 × 10⁻¹⁰ m, 1.4 × 10⁻⁹ m, and 1.2 × 10⁻⁸ m, respectively. Although the target molecule of oryctin in the beetle hemolymph remains obscure, our results showed that oryctin is a novel single domain Kazal-type inhibitor and could play a key role in protecting against bacterial infections.     

Kinetic Complexity, Homogeneity, and Copy Number of Chloroplast DNA from the Marine Alga Olisthodiscus luteus

The kinetic complexity of chloroplast DNA isolated from the chromophytic alga Olisthodiscus luteus has been determined. Using optical reassociation techniques, it was shown that the plastid DNA of this alga reacted as a single component with a second order rate constant of 4.1 molar⁻¹ and second⁻¹ (Cot_½ 0.24 molar second) under conditions equivalent to 180 millimolar Na⁺ and 60°C. Given the 92 × 10⁵ dalton complexity calculated for this chloroplast genome, an Olisthodiscus cell contains 650 plastome copies. Although this complement remains constant throughout the growth cycle of the organism, the ploidy level of an individual chloroplast shows significant plasticity and is dependent upon the number of chloroplasts present per cell. Experiments with the DNA fluorochrome Hoechst dye 33258 (bisbenzimide) demonstrate that plastids isolated from all phases of cell growth each possess a ring-shaped nucleoid containing detectable DNA. Olisthodiscus chloroplast DNA showed no sequence mismatch when thermal denaturation profiles of reassociated chloroplast DNA were examined, thus all plastome copies are essentially identical. Finally, reassociation studies demonstrated that no foldback (short inverted repeat) sequences were present in the plastid genome although significant hairpin loop structures were observed in control nuclear DNA samples.     

Diphosphopyridine nucleotide-linked D-lactate dehydrogenases from the horseshoe crab, Limulus polyphemus and the seaworm, Nereis virens. I. Physical and chemical properties

d-lactate dehydrogenase has been purified from horseshoe crab (Limulus polyphemus) skeletal muscle and the seaworm (Nereis virens). The purified Limulus dehydrogenase was shown to be a dimer, with a molecular weight of approximately 70 000. Sephadex gel filtration and equilibrium sedimentation yield molecular weights of about 80 000 and 70 000 respectively. Acid dissociation yields a molecular weight species of about 35 000. The native enzyme has an s^o₂₀^w of 3.95. Extrapolation of para-hydroxymercuribenzoate inhibition curves to 100% inhibition corresponds to two molecules of para-hydroxymercuribenzoate bound per molecule of enzyme. Studies on the stoichiometric binding of reduced coenzyme show two molecules bound per molecule of enzyme. The number of tryptic peptides has been found to be one-half that expected from the amino acid composition. The electrophoretic pattern of isoenzymic forms can be best interpreted as suggesting that the enzyme is dimeric. In vitro high salt, freeze-thaw hybridizations of the isolated Limulus muscle isoenzymes yield the electrophoretic pattern predicted by a dimeric structure.The physical properties ot Nereis lactate dehydrogenase have been found to be similar to those for the Limulus muscle lactate dehydrogenase.     

The equilibrium of the reaction catalysed by citrate oxaloacetate-lyase

1. A method of preparation and purification of citrate oxaloacetate-lyase (EC 4.1.3.6) from Aerobacter aerogenes is described. 2. The equilibrium of this reaction has been determined at pH 8·4 and 25°. It has been shown that K, i.e. [citrate³⁻]/[oxaloacetate_keto²⁻][acetate ⁻], is 3·08±0·72, but that K_app., i.e. [total citrate]/[total oxaloacetate][total acetate], is markedly affected by the initial concentrations of the reactants and magnesium. 3. The free-energy change during the cleavage of citrate has been calculated and compared with data from other sources. 4. The free energy of hydrolysis of acetyl-CoA has been evaluated from the present data. 5. A detailed knowledge of the interactions of the reactants with metal ions has been shown to be important in the calculation of the equilibrium constant and related thermodynamic functions.     

Confronting species distribution model predictions with species functional traits

Species distribution models are valuable tools in studies of biogeography, ecology, and climate change and have been used to inform conservation and ecosystem management. However, species distribution models typically incorporate only climatic variables and species presence data. Model development or validation rarely considers functional components of species traits or other types of biological data. We implemented a species distribution model (Maxent) to predict global climate habitat suitability for Grass Carp (Ctenopharyngodon idella). We then tested the relationship between the degree of climate habitat suitability predicted by Maxent and the individual growth rates of both wild (N = 17) and stocked (N = 51) Grass Carp populations using correlation analysis. The Grass Carp Maxent model accurately reflected the global occurrence data (AUC = 0.904). Observations of Grass Carp growth rate covered six continents and ranged from 0.19 to 20.1 g day⁻¹. Species distribution model predictions were correlated (r = 0.5, 95% CI (0.03, 0.79)) with observed growth rates for wild Grass Carp populations but were not correlated (r = −0.26, 95% CI (−0.5, 0.012)) with stocked populations. Further, a review of the literature indicates that the few studies for other species that have previously assessed the relationship between the degree of predicted climate habitat suitability and species functional traits have also discovered significant relationships. Thus, species distribution models may provide inferences beyond just where a species may occur, providing a useful tool to understand the linkage between species distributions and underlying biological mechanisms.     

Belowground carbon responses to experimental warming regulated by soil moisture change in an alpine ecosystem of the Qinghai–Tibet Plateau

Recent studies found that the largest uncertainties in the response of the terrestrial carbon cycle to climate change might come from changes in soil moisture under the elevation of temperature. Warming‐induced change in soil moisture and its level of influence on terrestrial ecosystems are mostly determined by climate, soil, and vegetation type and their sensitivity to temperature and moisture. Here, we present the results from a warming experiment of an alpine ecosystem conducted in the permafrost region of the Qinghai–Tibet Plateau using infrared heaters. Our results show that 3 years of warming treatments significantly elevated soil temperature at 0–100 cm depth, decreased soil moisture at 10 cm depth, and increased soil moisture at 40–100 cm depth. In contrast to the findings of previous research, experimental warming did not significantly affect NH ₄ ⁺‐N, NO ₃ ⁻‐N, and heterotrophic respiration, but stimulated the growth of plants and significantly increased root biomass at 30–50 cm depth. This led to increased soil organic carbon, total nitrogen, and liable carbon at 30–50 cm depth, and increased autotrophic respiration of plants. Analysis shows that experimental warming influenced deeper root production via redistributed soil moisture, which favors the accumulation of belowground carbon, but did not significantly affected the decomposition of soil organic carbon. Our findings suggest that future climate change studies need to take greater consideration of changes in the hydrological cycle and the local ecosystem characteristics. The results of our study will aid in understanding the response of terrestrial ecosystems to climate change and provide the regional case for global ecosystem models.     

Identification of IRF8, TMEM39A, and IKZF3-ZPBP2 as susceptibility loci for systemic lupus erythematosus in a large-scale multiracial replication study

Systemic lupus erythematosus (SLE) is a chronic heterogeneous autoimmune disorder characterized by the loss of tolerance to self-antigens and dysregulated interferon responses. The etiology of SLE is complex, involving both heritable and environmental factors. Candidate-gene studies and genome-wide association (GWA) scans have been successful in identifying new loci that contribute to disease susceptibility; however, much of the heritable risk has yet to be identified. In this study, we sought to replicate 1,580 variants showing suggestive association with SLE in a previously published GWA scan of European Americans; we tested a multiethnic population consisting of 7,998 SLE cases and 7,492 controls of European, African American, Asian, Hispanic, Gullah, and Amerindian ancestry to find association with the disease. Several genes relevant to immunological pathways showed association with SLE. Three loci exceeded the genome-wide significance threshold: interferon regulatory factor 8 (IRF8; rs11644034; p_meta-Euro = 2.08 × 10⁻¹⁰), transmembrane protein 39A (TMEM39A; rs1132200; p_meta-all = 8.62 × 10⁻⁹), and 17q21 (rs1453560; p_meta-all = 3.48 × 10⁻¹⁰) between IKAROS family of zinc finger 3 (AIOLOS; IKZF3) and zona pellucida binding protein 2 (ZPBP2). Fine mapping, resequencing, imputation, and haplotype analysis of IRF8 indicated that three independent effects tagged by rs8046526, rs450443, and rs4843869, respectively, were required for risk in individuals of European ancestry. Eleven additional replicated effects (5 × 10⁻⁸ < p_meta-Euro < 9.99 × 10⁻⁵) were observed with CFHR1, CADM2, LOC730109/IL12A, LPP, LOC63920, SLU7, ADAMTSL1, C10orf64, OR8D4, FAM19A2, and STXBP6. The results of this study increase the number of confirmed SLE risk loci and identify others warranting further investigation.     

Physical Map of the Channel Catfish Virus Genome: Location of Sites for Restriction Endonucleases EcoRI, HindIII, HpaI, and XbaI

The overall arrangement of nucleotide sequences in the DNA of channel catfish virus has been studied by cleavage with four restriction endonucleases. Physical maps have been developed for the location of sites for EcoRI, HindIII, HpaI, and XbaI. The sum of the molecular weights of fragments generated by each restriction enzyme indicates a molecular weight of approximately 86 × 10⁶ for the channel catfish virus genome. Fragments corresponding to the molecular ends of channel catfish virus DNA have been identified by their sensitivity to exonuclease treatment. The distribution of restriction sites in the genome shows that sequences included in a 12 × 10⁶-molecular weight region at one end are repeated with direct polarity at the other end, and that the overall genomic sequence order is nonpermuted.     

Evaluation of environmental factors affecting the genetic diversity,genetic structure,and the potential distribution of Rhododendron aureum Georgi under changing climate

Understanding genetic variation and structure, adaptive genetic variation, and its relationship with environmental factors is of great significance to understand how plants adapt to climate change and design effective conservation and management strategies. The objective of this study was to (I) investigate the genetic diversity and structure by AFLP markers in 36 populations of R. aureum from northeast China, (Ⅱ) reveal the relative contribution of geographical and environmental impacts on the distribution and genetic differentiation of R. aureum, (Ⅲ) identify outlier loci under selection and evaluate the association between outlier loci and environmental factors, and (Ⅳ) exactly calculate the development trend of population of R. aureum, as it is confronted with severe climate change and to provide information for designing effective conservation and management strategies. We found high genetic variation (I = 0.584) and differentiation among populations (Φ_ST  = 0.703) and moderate levels of genetic diversity within populations of R. aureum. A significant relationship between genetic distance and environmental distance was identified, which suggested that the differentiation of different populations was caused by environmental factors. Using BayeScan and Dfdist, 42 outlier loci are identified and most of the outlier loci are associated with climate or relief factors, suggesting that these loci are linked to genes that are involved in the adaptability of R. aureum to the environment. Species distribution models (SDMs) showed that climate warming will cause a significant reduction in suitable areas for R. aureum, especially under the RCP 85 scenario. Our results help to understand the potential response of R. aureum to climatic changes and provide new perspectives for R. aureum resource management and conservation strategies.     

Diffusion of a soluble protein,photoactivatable GFP,through a sensory cilium

Transport of proteins to and from cilia is crucial for normal cell function and survival, and interruption of transport has been implicated in degenerative and neoplastic diseases. It has been hypothesized that the ciliary axoneme and structures adjacent to and including the basal bodies of cilia impose selective barriers to the movement of proteins into and out of the cilium. To examine this hypothesis, using confocal and multiphoton microscopy we determined the mobility of the highly soluble photoactivatable green fluorescent protein (PAGFP) in the connecting cilium (CC) of live Xenopus retinal rod photoreceptors, and in the contiguous subcellular compartments bridged by the CC, the inner segment (IS) and the outer segment (OS). The estimated axial diffusion coefficients are D_CC = 2.8 ± 0.3, D_IS = 5.2 ± 0.6, and D_OS = 0.079 ± 0.009 µm² s⁻¹. The results establish that the CC does not pose a major barrier to protein diffusion within the rod cell. However, the results also reveal that axial diffusion in each of the rod’s compartments is substantially retarded relative to aqueous solution: the axial diffusion of PAGFP was retarded ∼18-, 32- and 1,000-fold in the IS, CC, and OS, respectively, with ∼20-fold of the reduction in the OS attributable to tortuosity imposed by the lamellar disc membranes. Previous investigation of PAGFP diffusion in passed, spherical Chinese hamster ovary cells yielded D_CHO = 20 µm² s⁻¹, and estimating cytoplasmic viscosity as D_aq/D_CHO = 4.5, the residual 3- to 10-fold reduction in PAGFP diffusion is ascribed to sub-optical resolution structures in the IS, CC, and OS compartments.     

An Unaccounted Fraction of Marine Biogenic CaCO3 Particles

Biogenic production and sedimentation of calcium carbonate in the ocean, referred to as the carbonate pump, has profound implications for the ocean carbon cycle, and relate both to global climate, ocean acidification and the geological past. In marine pelagic environments coccolithophores, foraminifera and pteropods have been considered the main calcifying organisms. Here, we document the presence of an abundant, previously unaccounted fraction of marine calcium carbonate particles in seawater, presumably formed by bacteria or in relation to extracellular polymeric substances. The particles occur in a variety of different morphologies, in a size range from <1 to >100 µm, and in a typical concentration of 10⁴–10⁵ particles L⁻¹ (size range counted 1–100 µm). Quantitative estimates of annual averages suggests that the pure calcium particles we counted in the 1–100 µm size range account for 2–4 times more CaCO₃ than the dominating coccolithophoride Emiliania huxleyi and for 21% of the total concentration of particulate calcium. Due to their high density, we hypothesize that the particles sediment rapidly, and therefore contribute significantly to the export of carbon and alkalinity from surface waters. The biological and environmental factors affecting the formation of these particles and possible impact of this process on global atmospheric CO₂ remains to be investigated.     

Calcium binding by particle-free supernatants of homogenates of skeletal muscle

A high molecular weight fraction of a soluble Marsh muscle-relaxing preparation has been shown to contain a calcium-complexing substance. By examining the nature of the competition between this fraction and chelex-100 for calcium at various total calcium concentrations it has been possible to calculate the concentration and calcium stability constant of this calcium-complexing substance. Taking into account dilutions which occur during the preparation of fractions containing this substance its concentration may be estimated at about 2·10^-4 in muscle and its calcium stability constant was found to be about 1.5·10⁵ M ^-1. Preliminary evidence suggests that the calcium-binding substance is a protein.     

Crystal Structure,Cytotoxicity and Interaction with DNA of Zinc (II) Complexes with o-Vanillin Schiff Base Ligands

Two new zinc complexes, Zn(HL¹)₂ (1) and [Zn₂(H₂L²)(OAc)₂]₂ (2) [H₂L¹ = Schiff base derived from o-vanillin and (R)-(+)-2-amino-3-phenyl-1-propanol, H₃L² = Schiff base derived from o-vanillin and 2-amino-2-ethyl-1,3-propanediol], have been synthesized and characterized by single crystal X-ray diffraction, elemental analyses, TG analyses, solid fluorescence, IR, UV-Vis and circular dichroism spectra. The structural analysis shows that complex 1 has a right-handed double helical chain along the crystallographic b axis. A homochiral 3D supramolecular architecture has been further constructed by intermolecular C-H··· π, O-H···O and C-H···O interactions. Complex 2 includes two crystallographically independent binuclear zinc molecules. The two binuclear zinc molecules are isostructural. The 2-D sheet supramolecular structure was formed by intermolecular hydrogen bonding interaction. The fluorescence of ligands and complexes in DMF at room temperature are studied. The interactions of two complexes with calf thymus DNA (CT-DNA) are investigated using UV-Vis, CD and fluorescence spectroscopy. The results show that complex 1 exhibits higher interaction with CT-DNA than complex 2. In addition, in vitro cytotoxicity of the complexes towards four kinds of cancerous cell lines (A549, HeLa, HL-60 and K562) were assayed by the MTT method. Investigations on the structures indicated that the chirality and nuclearity of zinc complexes play an important role on cytotoxic activity.