Rearing strategies of young dairy calves in relation to production, behaviour and welfare

Vasikoiden kasvatus yksilökarsinoissa, imemismahdollisuuden puute maitojuoton yhteydessä sekä pienet juomamäärät ovat tekijöitä, jotka mahdollisesti voivat vähentää vasikoiden hyvinvointia. Vasikoiden kasvatukseen etsitäänkin uusia tapoja, joissa eläinten käyttäytymistarpeet ja hyvinvointi otetaan entistä paremmin huomioon. Tässä väitöskirjassa vasikoiden kasvatusta on tarkasteltu sekä tuotannon että vasikoiden käyttäytymisen ja hyvinvoinnin kannalta. Väitöskirja koostuu kolmesta kokeesta, joista ensimmäisessä tutkittiin vasikoiden kasvatusta ryhmäkarsinoissa ulkona tai sisällä ja vasikoiden kasvatusta sisällä ryhmä- tai yksilökarsinoissa. Toisessa kokeessa vasikoiden annettiin imeä emiään rajoitetusti lypsyn jälkeen viiden tai kahdeksan viikon ajan ja kolmannessa selvitettiin vasikoiden veden juontia, kun vasikat saivat juomarehua vapaasti. Lisäksi kokeiden yhdistetystä aineistosta analysoitiin eri rehujen syöntimäärien suhdetta sekä rehujen vaikutusta kasvuun ennen ja jälkeen maidosta vieroituksen. Tutkimuksessa todettiin, että vasikoita voi ryhmässä kasvattaa kylmissä ja vaihtelevissa sääoloissa ulkona, kunhan ne hoidetaan ja ruokitaan erittäin huolellisesti. Kylmällä ilmalla vasikat saattavat kuitenkin syödä väkirehua vähemmän varsinkin, jos ruokailupaikka on ulkona ja makuualue sisällä. Ryhmässä kasvaneet vasikat aloittivat sekä kuivien rehujen syönnin että märehtimisen nuorempina kuin yksilökarsinassa kasvaneet. Ryhmissä esiintyvää käyttäytymisongelmaa, toisten vasikoiden imemistä, voidaan vähentää hoito- ja ruokintamenetelmillä. Annettaessa vasikoiden imeä emiään rajoitetusti lypsyn jälkeen vasikat oppivat imemään emiään hyvin nopeasti. Lypsytyö vaikeutui muutamien lehmien kohdalla, sillä ne pidättivät maitoa lypsettäessä. Saadessaan imeä rajoitetusti vasikat imivät suurehkoja maitomääriä kerrallaan. Vieroittaminen suurilta maitomääriltä viiden viikon iässä oli kuitenkin liian aikaista, koska vasikat eivät vielä syöneet riittävästi kuivia rehuja. Vieroitus emästä niin viiden kuin kahdeksankin viikon iässä aiheutti vasikoissa levottomuutta ja ääntelyn lisääntymistä. Saadessaan hapatettua juomarehua vapaasti vasikat joivat keskimäärin vain vähän vettä, olipa vesilähteenä avoin ämpäri tai vesinippa. Vasikoiden välillä oli suurta vaihtelua veden juontimäärissä. Viikkoa ennen maidosta vieroitusta vasikat joivat 0-3 l vettä päivässä. Vasikat joivat nipasta kerrallaan vähemmän vettä kuin ämpäristä, ja käyttivät enemmän aikaa päivässä veden juomiseen kuin vesiämpäristä juoneet vasikat. Suurin osa vasikoista joi vettä juomanipoista erikoisella tavalla esimerkiksi painamalla nippaa otsalla ja juomalla tippuvaa vettä. Vesinipat voivat olla siis vasikoille joko vaikeita tai epämukavia käyttää. Vasikoiden juoman maitomäärän lisääntyessä kasvu lisääntyy selvästi. Runsas maidon juominen vähentää kuitenkin kuivien rehujen syöntiä ja vieroitusvaiheessa kasvu voi hidastua. Vasikat olisikin tärkeää vieroittaa vähitellen, ettei muutoksia kasvuun tulisi. Syönti- ja kasvutulokset eivät aina anna oikeaa kuvaa kasvatusmenetelmien eroista eläinten hyvinvoinnin kannalta. Käyttäytyminen on herkkä hyvinvoinnin mittari ja se tulisikin aina huomioida eri kasvatusmenetelmiä arvioitaessa. .

Quantitative trait loci detection and benefits from marker-assisted selection in dairy cattle

Knowing the chromosomal areas or actual genes affecting the traits under selection would add more information to be used in the selection decisions which would potentially lead to higher genetic response. The first objective of this study was to map quantitative trait loci (QTL) affecting economically important traits in the Finnish Ayrshire population. The second objective was to investigate the effects of using QTL information in marker-assisted selection (MAS) on the genetic response and the linkage disequilibrium between the different parts of the genome. Whole genome scans were carried out on a grand-daughter design with 12 half-sib families and a total of 493 sons. Twelve different traits were studied: milk yield, protein yield, protein content, fat yield, fat content, somatic cell score (SCS), mastitis treatments, other veterinary treatments, days open, fertility treatments, non-return rate, and calf mortality. The average spacing of the typed markers was 20 cM with 2 to 14 markers per chromosome. Associations between markers and traits were analyzed with multiple marker regression. Significance was determined by permutation and genome-wise P-values obtained by Bonferroni correction. The benefits from MAS were investigated by simulation: a conventional progeny testing scheme was compared to a scheme where QTL information was used within families to select among full-sibs in the male path. Two QTL on different chromosomes were modelled. The effects of different starting frequencies of the favourable alleles and different size of the QTL effects were evaluated. A large number of QTL, 48 in total, were detected at 5% or higher chromosome-wise significance. QTL for milk production were found on 8 chromosomes, for SCS on 6, for mastitis treatments on 1, for other veterinary treatments on 5, for days open on 7, for fertility treatments on 7, for calf mortality on 6, and for non-return rate on 2 chromosomes. In the simulation study the total genetic response was faster with MAS than with conventional selection and the advantage of MAS persisted over the studied generations. The rate of response and the difference between the selection schemes reflected clearly the changes in allele frequencies of the favourable QTL. The disequilibrium between the polygenes and QTL was always negative and it was larger with larger QTL size. The disequilibrium between the two QTL was larger with QTL of large effect and it was somewhat larger with MAS for scenarios with starting frequencies below 0.5 for QTL of moderate size and below 0.3 for large QTL. In conclusion, several QTL affecting economically important traits of dairy cattle were detected. Further studies are needed to verify these QTL, check their presence in the present breeding population, look for pleiotropy and fine map the most interesting QTL regions. The results of the simulation studies show that using MAS together with embryo transfer to pre-select young bulls within families is a useful approach to increase the genetic merit of the AI-bulls compared to conventional selection.

Winter feeding strategies for suckler cows in cold climatic conditions

In Finland, suckler cow production is carried out in circumstances characterized by a long winter period and a short grazing period. The traditional winter housing system for suckler cows has been insulated or uninsulated buildings, but there is a demand for developing less expensive housing systems. In addition, more information is needed on new winter feeding strategies, carried out in inexpensive winter facilities with conventional (hay, grass silage, straw) or alternative (treated straw, industrial by-product, whole-crop silage) feeds. The new feeding techniques should not have any detrimental effects on animal welfare in order to be acceptable to both farmers and consumers. Furthermore, no official feeding recommendations for suckler cows are available in Finland and, thus, recommendations for dairy cows have been used. However, this may lead to over- or underfeeding of suckler cows and, finally, to decreased economic output. In Experiment I, second-calf beef-dairy suckler cows were used to compare the effects of diets based on hay (H) or urea-treated straw (US) at two feeding levels (Moderate; M vs. Low; L) on the performance of cows and calves. Live weight (LW) gain during the indoor feeding was lower for cows on level L than on level M. Cows on diet US lost more LW indoors than those on diet H. The cows replenished the LW losses on good pasture. Calf LW gain and cow milk production were unaffected by the treatments. Conception rate was unaffected by the treatments but was only 69%. Urea-treated straw proved to be a suitable winter feed for spring-calving suckler cows. Experiment II studied the effects of feeding accuracy on the performance of first- and second-calf beef-dairy cows and calves. In II-1, the day-to-day variation in the roughage offered ranged up to ± 40%. In II-2, the same variation was used in two-week periods. Variation of the roughages offered had minor effects on cow performance. Reproduction was unaffected by the feeding accuracy. Accurate feeding is not necessary for young beef-dairy crosses, if the total amount of energy offered over a period of a few weeks fulfills the energy requirements. Effects of feeding strategies with alternative feeds on the performance of mature beef-dairy and beef cows and calves were evaluated in Experiment III. Two studies consisted of two feeding strategies (Step-up vs. Flat-rate) and two diets (Control vs. Alternative). There were no differences between treatments in the cow LW, body condition score (BCS), calf pre-weaning LW gain and cow reproduction. A flat-rate strategy can be practised in the nutrition of mature suckler cows. Oat hull based flour-mill by product can partly replace grass silage and straw in the winter diet. Whole-crop barley silage can be offered as a sole feed to suckler cows. Experiment IV evaluated during the winter feeding period the effects of replacing grass silage with whole-crop barley or oat silage on mature beef cow and calf performance. Both whole-crop silages were suitable winter feeds for suckler cows in cold outdoor winter conditions. Experiment V aimed at assessing the effects of daily feeding vs. feeding every third day on the performance of mature beef cows and calves. No differences between the treatments were observed in cow LW, BCS, milk production and calf LW. The serum concentrations of urea and long-chain fatty acids were increased on the third day after feeding in the cows fed every third day. Despite of that the feeding every third day is an acceptable feeding strategy for mature suckler cows. Experiment VI studied the effects of feeding levels and long-term cold climatic conditions on mature beef cows and calves. The cows were overwintered in outdoor facilities or in an uninsulated indoor facility. Whole-crop barley silage was offered either ad libitum or restricted. All the facilities offered adequate shelter for the cows. The restricted offering of whole-crop barley silage provided enough energy for the cows. The Finnish energy recommendations for dairy cows were too high for mature beef breed suckler cows in good body condition at housing, even in cold conditions. Therefore, there is need to determine feeding recommendations for suckler cows in Finland. The results showed that the required amount of energy can be offered to the cows using conventional or alternative feeds provided at a lower feeding level, with an inaccurate feeding, flat-rate feeding or feeding every third day strategy. The cows must have an opportunity to replenish the LW and BCS losses at pasture before the next winter. Production in cold conditions can be practised in inexpensive facilities when shelter against rain and wind, a dry resting place, adequate amounts of feed suitable for cold conditions and water are provided for the animals as was done in the present study.

Neospora caninum and reproductive wastage in extensively managed Queensland beef herds

Objective To compare reproduction in extensively managed, tropically adapted beef cows that were either seropositive or seronegative to Neospora caninum. Design Longitudinal study of cows within management groups. Methods Compare pregnancy with weaning outcomes for 502 seropositive and 3255 seronegative cows in 25 management groups. Results We found N. caninum in all herds, with an average of 20% of 2640 tested animals seropositive within management group; prevalence varied between 0% and 94%. At 7 of 10 sites assessed, there was evidence of horizontal transmission of N. caninum. There was no overall difference in pregnancy rate (79% vs 75%; P > 0.05), reproductive wastage after confirmed pregnancy diagnosis (11% vs 10%; P > 0.05) or weaning rate (67% vs 68%; P > 0.05) between seronegative and seropositive cows, respectively. In one herd where a combination of risk factors for N. caninum was present, a significant reduction in pregnancy rate occurred after the 6 months mating (85% vs 69%; P < 0.05). The fetal and calf losses observed were lowest in south-east Queensland (4.3% of 117 pregnancies), highest in north-west Queensland (15.5% of 413 pregnancies) and intermediate in north-east Queensland (10.2% of 1625 pregnancies). Other infectious agents that are known to cause reproductive wastage were endemic in many herds, though none appeared to cause significant fetal or calf loss in this study. Conclusion Despite a high prevalence of N. caninum, there was no apparent effect on beef cattle reproduction, but there is potential to cause reproductive wastage if known risk factors to neosporosis are in effect.

Demographic and functional responses of wild dogs to poison baiting

Lethal control of wild dogs - that is Dingo (Canis lupus dingo) and Dingo/Dog (Canis lupus familiaris) hybrids - to reduce livestock predation in Australian rangelands is claimed to cause continental-scale impacts on biodiversity. Although top predator populations may recover numerically after baiting, they are predicted to be functionally different and incapable of fulfilling critical ecological roles. This study reports the impact of baiting programmes on wild dog abundance, age structures and the prey of wild dogs during large-scale manipulative experiments. Wild dog relative abundance almost always decreased after baiting, but reductions were variable and short-lived unless the prior baiting programme was particularly effective or there were follow-up baiting programmes within a few months. However, age structures of wild dogs in baited and nil-treatment areas were demonstrably different, and prey populations did diverge relative to nil-treatment areas. Re-analysed observations of wild dogs preying on kangaroos from a separate study show that successful chases that result in attacks of kangaroos by wild dogs occurred when mean wild dog ages were higher and mean group size was larger. It is likely that the impact of lethal control on wild dog numbers, group sizes and age structures compromise their ability to handle large difficult-to-catch prey. Under certain circumstances, these changes sometimes lead to increased calf loss (Bos indicus/B. taurus genotypes) and kangaroo numbers. Rangeland beef producers could consider controlling wild dogs in high-risk periods when predation is more likely and avoid baiting at other times.

Baseline and greenhouse-gas emissions in extensive livestock enterprises, with a case study of feeding lipid to beef cattle

For accurate calculation of reductions in greenhouse-gas (GHG) emissions, methodologies under the Australian Government's Carbon Farming Initiative (CFI) depend on a valid assessment of the baseline and project emissions. Life-cycle assessments (LCAs) clearly show that enteric methane emitted from the rumen of cattle and sheep is the major source of GHG emissions from livestock enterprises. Where a historic baseline for a CFI methodology for livestock is required, the use of simulated data for cow-calf enterprises at six sites in southern Australia demonstrated that a 5-year rolling emission average will provide an acceptable trade off in terms of accuracy and stability, but this is a much shorter time period than typically used for LCA. For many CFI livestock methodologies, comparative or pair-wise baselines are potentially more appropriate than historic baselines. A case study of lipid supplementation of beef cows over winter is presented. The case study of a control herd of 250 cows used a comparative baseline derived from simple data on livestock numbers and class of livestock to quantify the emission abatement. Compared with the control herd, lipid supplementation to cows over winter increased livestock productivity, total livestock production and enterprise GHG emissions from 990 t CO2-e to 1022 t CO2-e. Energy embodied in the supplement and extra diesel used in transporting the supplement diminished the enteric-methane abatement benefit of lipid supplementation. Reducing the cow herd to 238 cows maintained the level of livestock production of the control herd and reduced enterprise emissions to 938 t CO2-e, but was not cost effective under the assumptions of this case study.

Welfare outcomes for 3- and 6-month-old beef calves in a tropical environment castrated surgically or by applying rubber rings

Castration of cattle using rubber rings is becoming increasingly popular due to the perceived ease of the procedure and greater operator safety when compared with surgical castration. Few comparative studies have investigated the effects of different castration methods and calf age on welfare outcomes, particularly in a tropical environment. Thirty Belmont Red (a tropically adapted breed), 3-month-old (liveweight 71–119 kg) and 30, 6-month-old (liveweight 141–189 kg) calves were assigned to a two age × three castration (surgical, ring and sham) treatment factorial study (Surg3, Surg6, Ring3, Ring6, Sham3 and Sham6, n = 10 for each treatment group). Welfare outcomes were assessed post-castration using: behaviour for 2 weeks; blood parameters (cortisol and haptoglobin concentrations) to 4 weeks; wound healing to 5 weeks; and liveweights to 6 weeks. More Surg calves struggled during castration compared with Sham and Ring (P < 0.05, 90 ± 7% vs. 20 ± 9% and 24 ± 10%) and performed more struggles (1.9 ± 0.2, 1.1 ± 0.3 and 1.1 ± 0.3 for Surg, Sham and Ring, respectively), suggesting that surgical castration caused most pain during performance of the procedure. A significant (P < 0.05) time × castration method × age interaction for plasma cortisol revealed that concentrations decreased most rapidly in Sham; the Ring6 calves failed to show reduced cortisol concentrations at 2 h post-castration, unlike other treatment groups. By 7 h post-castration, all treatment groups had similar concentrations. A significant (P < 0.01) interaction between time and castration method showed that haptoglobin concentrations increased slightly to 0.89 and 0.84 mg/mL for Surg and Ring, respectively over the first 3 days post-castration. Concentrations for Surg then decreased to levels similar to Sham by day 21 and, although concentrations for Ring decreased on day 7 to 0.76 mg/mL, they increased significantly on day 14 to 0.97 mg/mL before reducing to concentrations similar to the other groups (0.66 mg/mL) by day 21. Significantly (P < 0.05) more of the wounds of the 3-month compared with the 6-month calves scored as ‘healed’ at day 7 (74% vs. 39%), while more (P = 0.062) of the Surg than Ring scored as ‘healed’ at day 21 (60% vs. 29%). At day 14 there were significantly (P < 0.05) fewer healed wounds in Ring6 compared with other treatment groups (13% vs. 40–60%). Liveweight gain was significantly (P < 0.05) greater in 3-month (0.53 kg/day) than in 6-month calves (0.44 kg/day) and in Sham calves (P < 0.001, 0.54 kg/day), than in Ring (0.44 kg/day) and Surg (0.48 kg/day) calves. Overall, welfare outcomes were slightly better for Surg than Ring calves due to reduced inflammation and faster wound healing, with little difference between age groups.

Welfare outcomes for 3- and 6-month-old beef calves in a tropical environment castrated surgically or by applying rubber rings

Castration of cattle using rubber rings is becoming increasingly popular due to the perceived ease of the procedure and greater operator safety when compared with surgical castration. Few comparative studies have investigated the effects of different castration methods and calf age on welfare outcomes, particularly in a tropical environment. Thirty Belmont Red (a tropically adapted breed), 3-month-old (liveweight 71–119 kg) and 30, 6-month-old (liveweight 141–189 kg) calves were assigned to a two age × three castration (surgical, ring and sham) treatment factorial study (Surg3, Surg6, Ring3, Ring6, Sham3 and Sham6, n = 10 for each treatment group). Welfare outcomes were assessed post-castration using: behaviour for 2 weeks; blood parameters (cortisol and haptoglobin concentrations) to 4 weeks; wound healing to 5 weeks; and liveweights to 6 weeks. More Surg calves struggled during castration compared with Sham and Ring (P < 0.05, 90 ± 7% vs. 20 ± 9% and 24 ± 10%) and performed more struggles (1.9 ± 0.2, 1.1 ± 0.3 and 1.1 ± 0.3 for Surg, Sham and Ring, respectively), suggesting that surgical castration caused most pain during performance of the procedure. A significant (P < 0.05) time × castration method × age interaction for plasma cortisol revealed that concentrations decreased most rapidly in Sham; the Ring6 calves failed to show reduced cortisol concentrations at 2 h post-castration, unlike other treatment groups. By 7 h post-castration, all treatment groups had similar concentrations. A significant (P < 0.01) interaction between time and castration method showed that haptoglobin concentrations increased slightly to 0.89 and 0.84 mg/mL for Surg and Ring, respectively over the first 3 days post-castration. Concentrations for Surg then decreased to levels similar to Sham by day 21 and, although concentrations for Ring decreased on day 7 to 0.76 mg/mL, they increased significantly on day 14 to 0.97 mg/mL before reducing to concentrations similar to the other groups (0.66 mg/mL) by day 21. Significantly (P < 0.05) more of the wounds of the 3-month compared with the 6-month calves scored as ‘healed’ at day 7 (74% vs. 39%), while more (P = 0.062) of the Surg than Ring scored as ‘healed’ at day 21 (60% vs. 29%). At day 14 there were significantly (P < 0.05) fewer healed wounds in Ring6 compared with other treatment groups (13% vs. 40–60%). Liveweight gain was significantly (P < 0.05) greater in 3-month (0.53 kg/day) than in 6-month calves (0.44 kg/day) and in Sham calves (P < 0.001, 0.54 kg/day), than in Ring (0.44 kg/day) and Surg (0.48 kg/day) calves. Overall, welfare outcomes were slightly better for Surg than Ring calves due to reduced inflammation and faster wound healing, with little difference between age groups.

Photocytotoxic 3d-Metal Scorpionates with a 1,8-Naphthalimide Chromophore Showing Photoinduced DNA and Protein Cleavage Activity

Ternary 3d-metal complexes of formulation [M(Tp(Ph))(py-nap)](ClO4)(1-3), where M is Co(II) (1), Cu(II) (2), and Zn(II) (3); Tp(Ph) is anionic tris (3-phenylpyrazolyl)borate; and py-nap is a pyridyl ligand with a conjugated 1,8-naphthalimide moiety, have been prepared from the reaction of metal perchlorate with KTp(Ph) and py-nap in CH2Cl2. The complexes have been characterized from analytical and physicochemical data. The complexes are stable in solution as evidenced from the electrospray ionization mass spectrometry data. The complexes show good binding propensity with calf thymus (CT) DNA, giving binding constant (K-b) values of similar to 10(5) M-1 and a molecular ``light-switch'' effect that results in an enhancement of the emission intensity of the naphthalimide chromophore on binding to CT DNA. The complexes do not show any hydrolytic cleavage of DNA. They show poor chemical nuclease activity in the presence of 3-mercaptopropionic acid or hydrogen peroxide (H2O2). The Co(II) and Cu(II) complexes exhibit oxidative pUC19 DNA cleavage activity in UV-A light of 365 rim. The Zn(II) complex shows moderate DNA photocleavage activity at 365 nm. The Cu(II)complex 2 displays photoinduced DNA cleavage activity in red light of 647.1 nm and 676 rim and near-IR light of >750 rim. A mechanistic studyin UV-A and visible light suggests the involvement of the hydroxyl radical as the reactive species in the DNA photocleavage reactions. The complexes also show good bovine serum albumin (BSA) protein binding propensity, giving K-BSA values of similar to 10(5) M-1. Complexes 1 and 2 display significant photoinduced BSA cleavage activity in UV-A light. The Co(II) complex 1 shows a significant photocytotoxic effect in HeLa cervical cancer cells on exposure to UV-A light of 365 nm, giving an IC50 value of 32 mu M. The IC50 value for the py-nap ligand alone is 41.42 mu m in UV-A light. The IC50 value is >200 mu M in the dark, indicating poor dark toxicity of 1. The Cu(II) complex 2 exhibits moderate photocytotoxicity and significant dark toxicity, giving IC50 values of 18.6 mu m and 29.7 mu m in UV-A light and in the dark, respectively.

Immunological studies on nucleic-acids and their components .5. Antibodies specific to a deoxyribodinucleotide sequence

Antibodies were raised in rabbits against the bovine serum albumin conjugate of dpApT. Analysis by double diffusion in agar gel and quantitative precipitation test showed the presence of antibodies specific to the hapten in the antisera. Quantitative data on the specificity of the antibodies were obtained by studying the inhibition of the binding of 3H-dpApT to the anti-sera by various nonradioactive mono- and oligonucleotides, using a nitrocellulose membrane binding assay. The antibodies were found to be highly specific for the dinucleotide sequence dpApT. The antibodies were able to bind to synthetic oligonucleotides containing the sequence dpApT and to denatured calf thymus DNA.

Interaction of palladium (II) with DNA

The nature of interaction of palladium(II) with calf thymus DNA was studied using viscometry, ultraviolet, visible and infrared spectrophotometry and optical rotatory disperison and circular dichroism measurements. The results indicate that Pd(II) interacts with both the phosphate and bases of DNA. The ORD/CD data indicate that the binding of Pd(II) to DNA brings about considerable conformational changes in DNA.

New ternary copper(II) complexes of L-alanine and heterocyclic bases: DNA binding and oxidative DNA cleavage activity

Four new ternary copper(II) complexes of alpha-amino acid having polypyridyl bases of general formulation [Cu(L-ala)(B)(H2O)](X)(1-4), where L-ala is L-alanine, B is an N,N-donor heterocyclic base, viz. 2,2'-bipyridine (bpy, 1), 1,10-phenanthroline (phen, 2) and 5,6-phenanthroline dione (dione, 3), dipyrido[3,2:2',3'-f] quinoxaline (dpq, 4), and X = ClO4-/NO3- are synthesized, characterized by various spectroscopic and X-ray crystallographic methods. The complexes show a distorted square-pyramidal (4 + 1) CuN3O2 coordination geometry. The one-electron paramagnetic complexes (1-4) display a low energy d-d band near 600 nm in aqueous medium and show a quasi-reversible cyclic voltammetric response due to one-electron Cu(II)/Cu(I) reduction near - 100 mV (versus SCE) in DMF-0.1 M TBAP. Binding interactions of the complexes with calf thymus DNA (CT-DNA) were investigated by UV-Vis absorption titration, ethidium bromide displacement assay, viscometric titration experiment and DNA melting studies. All the complexes barring the complexes 1 and 3 are avid binder to the CT-DNA in the DNA minor groove giving an order: 4 > 2 >>>1, 3. The complexes 2 and 4 show appreciable chemical nuclease activity in the presence of 3-mercaptopropionic acid (MPA) as a reducing agent. Hydroxyl radical was investigated to be the DNA cleavage active species. Control experiments in the presence of distamycin-A show primarily minor groove-binding propensity for the complexes 2 and 4 to the DNA.

Interaction of surfactants with DNA. Role of hydrophobicity and surface charge on intercalation and DNA melting

A probe, 9-(anthrylmethyl)trimethylammonium chloride, 1, was prepared. 1 binds to calf-thymus DNA or Escherichia coli genomic DNA with high affinity, as evidenced from the absorption titration. Strong hypochromism, spectral broadening and red-shifts in the absorption spectra were observed. Half-reciprocal plot constructed from this experiment gave binding constant of 5±0.5×104 M−1 in base molarity. We employed this anthryl probe-DNA complex for studying the effects of addition of various surfactant to DNA. Surfactants of different charge types and chain lengths were used in this study and the effects of surfactant addition to such probe-DNA complex were compared with that of small organic cations or salts. Addition of either salts or cationic surfactants led to structural changes in DNA and under these conditions, the probe from the DNA-bound complex appeared to get released. However, the cationic surfactants could induce such release of the probe from the probe-DNA complex at a much lower concentration than that of the small organic cations or salts. In contrast the anionic surfactants failed to promote any destabilization of such probe-DNA complexes. The effects of additives on the probe-DNA complexes were also examined by using a different technique (fluorescence spectroscopy) using a different probe ethidium bromide. The association complexes formed between the cationic surfactants and the plasmid DNA pTZ19R, were further examined under agarose gel electrophoresis and could not be visualized by ethidium bromide staining presumably due to cationic surfactant-induced condensation of DNA. Most of the DNA from such association complexes can be recovered by extraction of surfactants with phenol-chloroform. Inclusion of surfactants and other additives into the DNA generally enhanced the DNA melting temperatures by a few °C and at high [surfactant], the corresponding melting profiles got broadened.

Photocytotoxic Oxovanadium(IV) Complexes Showing Light-Induced DNA and Protein Cleavage Activity

Oxovanadium(IV) complexes [VO(L)(B)]Cl-2 (1-3), where L is bis(2-benzimidazolylmethyl)amine and B is 1,10-phenanthroline(phen),dipyrido[3,2-d:2',3'-f]quinoxaline(dpq) or dipyrido[3,2-a:2',3'-c]phenazine (dppz), have been prepared, characterized, and their photo-induced DNA and protein cleavage activity studied. The photocytotoxicity of complex 3 has been studied using adenocarcinoma A549 cells, The phen complex 1, structurally characterized by single-crystal X-ray crystallography, shows the presence of a vanadyl group in six-coordinate VON5 coordination geometry. The ligands L and phen display tridentate and bidentate N-donor chelating binding modes, respectively. The complexes exhibit a d-d band near 740 nm in 15% DMF-Tris-HCl buffer (pH 7.2). The phen and dpq complexes display an irreversible cathodic cyclic voltammetric response near -0.8 V in 20% DMF-Tris-HCl buffer having 0.1 M KCl as supporting electrolyte. The dppz complex 3 exhibits a quasi-reversible voltammogram near -0.6 V (vs SCE) that is assignable to the V(IV)-V(III)couple. The complexes bind to calf thymus DNA giving binding constant values in the range of 6.6 x 10(4)-2.9 x 10(5) M-1. The binding site size, thermal melting and viscosity binding data suggest DNA surface and/or groove binding nature of the complexes. The complexes show poor ``chemical nuclease'' activity in dark in the presence of 3-mercaptopropionic acid or hydrogen peroxide. The dpq and dppz complexes are efficient photocleavers of plasmid DNA in UV-A light of 365 nm via a mechanistic pathway that involves formation of both singlet oxygen and hydroxyl radicals. The complexes show significant photocleavage of DNA in near-IR light (>750 nm) via hydroxyl radical pathway. Among the three complexes, the dppz complex 3 shows significant BSA and lysozyme protein cleavage activity in UV-A light of 365 nm via hydroxyl radical pathway. The dppz complex 3 also exhibits photocytotoxicity in non-small cell lung carcinoma/human lung adenocarcinoma A549 cells giving IC50 value of 17 mu M in visible light(IC50 = 175 mu M in dark).

Oxovanadium(IV) complexes of phenanthroline bases: the dipyridophenazine complex as a near-IR photocytotoxic agent

Oxovanadium(IV) complexes [VOCl(B)(2)]Cl (1-3) of phenanthroline bases (B), viz. 1,10-phenanthroline (phen in 1), dipyrido[3,2-d: 2', 3'-f] quinoxaline (dpq in 2) and dipyrido[3,2-a: 2', 3'-c] phenazine (dppz in 3), have been prepared, characterized and their DNA and protein binding, photo-induced DNA and protein cleavage activity andm photocytotoxicity have been studied. Complex 2, structurally characterized by X-ray crystallography, shows the presence of a vanadyl group in VOClN4 coordination geometry. The dpq ligand displays a chelating mode of binding with a N-donor site trans to the oxo-group. The chloride ligand is cis to the oxo-group. The one-electron paramagnetic complexes show a d-d band near 715 nm in 15% DMF-Tris-HCl buffer. The complexes are redox active exhibiting a V(IV)/V(III) redox couple within -0.5 to -0.7 V vs. SCE in 20% DMF-Tris-HCl/0.1 M KCl. The complexes bind to calf thymus (CT) DNA in the order: 3 (dppz) > 2 (dpq) > 1 (phen). The binding data reveal the groove and/or partial intercalative DNA binding nature of the complexes. The complexes show chemical nuclease'' activity in the dark in the presence of 3-mercaptopropionic acid or hydrogen peroxide via a hydroxyl radical pathway. The dpq and dppz complexes are efficient photocleavers of DNA in UV-A light of 365 nm forming reactive singlet oxygen (O-1(2)) and hydroxyl radical ((OH)-O-center dot) species. Complexes 2 and 3 also show DNA cleavage activity in red light (> 750 nm) by an exclusive (OH)-O-center dot pathway. The complexes display a binding propensity to bovine serum albumin (BSA) protein giving K-BSA values in the range of 7.1 x 10(4)-1.8 x 10(5) M-1. The dppz complex 3 shows BSA and lysozyme protein cleavage activity in UV-A light of 365 nm via (OH)-O-center dot pathway. The dppz complex 3 exhibits significant PDT effect in human cervical cancer HeLa cells giving IC50 values of 1.0 mu M and 12.0 mu M in UV-A and visible light, respectively (IC50 = > 100 mu M in the dark).