Mango explant browning: Effect of ontogenic age,mycorrhization and pre-treatments

The in vitro performance of mango shoot culture is delimited by several factors, of which explant necrosis and media browning are considered as major constraints for successful exploitation of such an important commercial crop. Our results showed that source of explants had a significant effect on the performance of in vitro cultures of mango. The variations in survival of explants collected from glasshouse grown seedlings and field-grown stock plants indicated towards differences between their physiological/ontogenic age. Though, chronologically, both are young, the glasshouse grown shoots are ontogenetically younger and; therefore, responded better over field-grown shoots. Improved performance of explants harvested from mycorrhizal plants suggests integration of mycorrhizal biotechnology with tissue culture biotechnology in order to achieve better results as mycorrhiza being a well-known stress alleviator may help explants mitigate in vitro stresses. Furthermore, shoot tip explants of field-grown ‘Amrapali’ mango was assayed for their browning propensity at pre- and post-culture stages. Status of different bio-chemicals such as in vivo phenol, in vitro phenol exudation, phenylalanine ammonia lyase, peroxidase and polyphenol oxidase as affected by various pre-treatments were estimated to establish the relationship of these bio-chemicals with necrosis of mango shoot cultures. The different pre-treatments comprised etiolation of newly emerged shoots (5–7 days old) of stock plants using black polythene for 7 days, etiolation treatment + agitation of explants in antioxidant solution (antioxidants: ascorbic acid at 100 mg l⁻¹ + citric acid at 50 mg l⁻¹), etiolation treatment + agitation of explants in polyvinylpyrrolidone solution (PVP) at 0.2% and non-etiolated control. Of these, explants treated with PVP proved to be superior to other treatments with regards to explant necrosis percentage as such explants exhibited least activities of phenols and oxidative enzymes. Correlation studies indicated existence of high positive correlation between explant necrosis and these bio-chemicals.     

Suppression of Botryosphaeria canker of apple by arbuscular mycorrhizal fungi

Stem brown canker or Botryosphaeria canker disease impairs the growth and kills the shoots, limbs and even trunks of infected apple trees. Apple roots are usually colonized by arbuscular mycorrhizal fungi, which may have a positive influence on plant growth and suppression of diseases. In order to assess the efficacy of AM to suppress the disease severity and plant growth enhancement, nine AMF inoculation treatments (Sclerocystis dussi, Glomus intraradices, G. fasciculatum, G. bagyaraji, G. leptotichum, G. monosporum, Gigaspora margarita, a mixed AM culture and a non-mycorrhizal control treatment) were used in this present study. Two-year-old potted apple plants, maintained under glasshouse conditions, were either pre-inoculated with AMF followed by stem inoculation with Botryosphaeria ribis or simultaneously inoculated with Botryosphaeria ribis and AM. The results indicated that the incidence of canker was less severe in plants inoculated with AMF in comparison to non-mycorrhizal control. Timing of inoculation also had a significant effect on disease development and plant survival. Plants pre-inoculated with mycorrhiza performed better over those inoculated simultaneously with Botryosphaeria ribis and AM fungi. Furthermore, AM inoculation resulted in improved survival and growth of AMF-colonized plants; though, it varied by species of AM fungi utilized.     

Comparative Analysis of the Outer Membrane Protein Profiles of Isolates of the Pasteurella multocida (B:2) Associated with Haemorrhagic Septicaemia

Outer membrane proteins (OMP) of P. multocida (serotype B:2) field isolates (n = 6) and a vaccine strain (P-52) were extracted by a sarkosyl method and characterized using SDS-PAGE and immunoblotting. About 20 polypeptide bands were observed in the profile of the vaccine strain with MW ranging from 16 to 90 kDa and, based on band thickness and intensity of staining, three polypeptides of MW 31, 33 and 37 kDa were considered to be the major OMPs. The profiles of the field isolates showed minor differences when compared with that of the vaccine strain. The OMP of 33 kDa was only expressed by the vaccine strain. Four field isolates expressed an OMP of 39 kDa, which did not appear in the profiles of the remaining two field isolates and the P-52 strain. Similarly, an OMP of 25 kDa was exclusively seen in the profile of a single isolate. By immunoblotting studies, using anti-P. multocida (P-52) whole-cell hyperimmune serum raised in rabbits as well as buffalo immune sera, it became evident that the polypeptide of 37 kDa was the most antigenic OMP in the profiles of all the isolates, including the P-52 strain. Other polypeptides were either weakly antigenic or visible in the profile of only a few of the isolates. The study thus identified the major OMP of P. multocida (B:2) and suggested that this highly antigenic 37 kDa OMP has potential for further protective and immunodiagnostic studies.     

Efficacy of disinfectants and hand sanitizers against avian respiratory viruses

Disinfectants play a major role in the control of animal diseases by decontaminating the farm environment. We evaluated the virucidal efficacy of nine commonly used disinfectants on a nonporous surface contaminated experimentally with avian metapneumovirus (aMPV), avian influenza virus, or Newcastle disease virus (NDV). Phenolic compounds and glutaraldehyde were found to be the most effective against all three viruses. Quaternary ammonium compounds were effective against aMPV but not against the other two viruses. In addition, efficacy of commercially available hand sanitizers was evaluated on human fingers contaminated with aMPV and NDV. All three hand sanitizers tested were found to be effective against both viruses within 1 min of application on fingers.     

Bovine brucellosis – a comprehensive review

Brucellosis is a zoonotic disease of great animal welfare and economic implications worldwide known since ancient times. The emergence of brucellosis in new areas as well as transmission of brucellosis from wild and domestic animals is of great significance in terms of new epidemiological dimensions. Brucellosis poses a major public health threat by the consumption of non-pasteurized milk and milk products produced by unhygienic dairy farms in endemic areas. Regular and meticulous surveillance is essentially required to determine the true picture of brucellosis especially in areas with continuous high prevalence. Additionally, international migration of humans, animals and trade of animal products has created a challenge for disease spread and diagnosis in non-endemic areas. Isolation and identification remain the gold standard test, which requires expertise. The advancement in diagnostic strategies coupled with screening of newly introduced animals is warranted to control the disease. Of note, the diagnostic value of miRNAs for appropriate detection of B. abortus infection has been shown. The most widely used vaccine strains to protect against Brucella infection and related abortions in cattle are strain 19 and RB51. Moreover, it is very important to note that no vaccine, which is highly protective, safe and effective is available either for bovines or human beings. Research results encourage the use of bacteriophage lysates in treatment of bovine brucellosis. One Health approach can aid in control of this disease, both in animals and man.     

Neuronal nitric oxide synthase immunoreactivity in forebrain,pineal, and pituitary of <Emphasis Type="Italic">Oreochromis mossambicus</Emphasis> (Tilapia)

Ultrastructural localization of neuronal nitric oxide synthase (nNOS) in olfactory receptor neurons (ORNs) and immunohistochemical detection of the enzyme in forebrain, pituitary, and pineal were undertaken in the teleost Oreochromis mossambicus. Application of post-embedding immunoelectron microscopy revealed nNOS-labeled gold particles on the cilia, microvilli, mitochondria, and Golgi complex of the ORNs. Gold particles were also seen adhered to microtubules in the axons that extend to the olfactory nerve layer in the olfactory bulb. With light microscopy, nNOS-immunoreactive neurons were seen in preoptic area, nucleus entopeduncularis, and parvocellular, and magnocellular subdivisions of nucleus preopticus (NPO). Numerous cerebrospinal fluid-contacting cells lining the wall of the third ventricle at the level of the NPO showed intense immunoreactivity. Intense to moderate immunoreactivity was observed in the neurons of suprachiasmatic nucleus, nucleus lateralis tuberis pars lateralis, and nucleus recessus lateralis. While several immunoreactive fibers were detected in medial olfactory tract, suprachiasmatic area, and hypothalamo-hypophyseal tract, a few were seen throughout the telencephalon, in the optic chiasma, tuberal area, and inferior lobes. In the pituitary, nNOS-containing fibers were seen in the neurohypophysis, rostral pars distalis, proximal pars distalis, and pars intermedia. While intense immunoreactivity was noticed in some cells in the pineal, immunoreactive fibers were detected in the pineal stalk as well as parenchyma. We suggest that nitric oxide may play a role in processing olfactory and photic information, circadian rhythms, and neuroendocrine regulation in tilapia.     

Alleviation of drought stress in maize (Zea mays L.) by using endogenous endophyte Bacillus subtilis in North West Himalayas

ABSTRACT

In the present study, we reported the isolation and molecular characterisation of 1-aminocyclopropane-1-carboxylic acid (ACC) deaminase-producing endophyte and its effect on alleviating drought stress in maize. Ten morphologically distinct indigenous plant growth-promoting rhizobacteria (PGPR) from maize roots and rhizosphere were screened for multiple plant growth-promoting (PGP) traits, and of ten, two strains (DHK and B1N1) possessing maximum PGP traits were evaluated at three water stress regimes in maize: (i) 80% field capacity (FC), (ii) 60% FC, and (iii) 40% FC for 45 days, starting 15 days after sowing to the maturity. Inoculation of DHK strain with maize at 80% FC induced a significant increase in plant biomass (root biomass, 86.67%; shoot biomass, 111.63%) together with decreased reactive oxygen species and increased activity of antioxidant enzymes (superoxide dismutase, 14.11?U/g fresh weight; peroxidase, 1.14?U/g fresh weight and catalase; 14.91?U/g fresh weight) compared to uninoculated control at same water regime (80% FC). The derivative strain also significantly accrued nutrients in maize and enhanced total chlorophyll and amino acid content in comparison with non-inoculated plants. 16S rDNA analysis of DHK strain revealed its lineage to Bacillus subtilis. Present investigations demonstrated the potential of the bacterial partner in alleviating drought stress in maize.     

Induction of Shikonin production in hairy root cultures of <Emphasis Type="Italic">Arnebia hispidissima</Emphasis> via <Emphasis Type="Italic">Agrobacterium rhizogenes</Emphasis>-mediated genetic transformation

Data presented herein provides a rapid and efficient method for Agrobacterium rhizogenes-mediated genetic transformation of Arnebia hispidissima for hairy root cultures as well as for enhancing Shikonin production. Etiolated explants viz. shoot tip, nodal, leaf and internodal segments were co-cultivated with Agrobacterium rhizogenes for induction of hairy root. Among the various explants employed, leaf explant showed maximum 70.7% response followed by shoot tip 48.3%, nodal segment 38.7% and internodal segment 9.3%. Integration of Ri plasmid rolB gene in the transformed hairy root cultures was confirmed by PCR analysis using forward (FrolB) and reverse (RrolB) primers of rolB gene resulting in the amplification of 0 ∼ 0.8 kb fragments. Medium compositions have been optimized for in vitro induction of Shikonin in hairy root cultures of Arnebia hispidissima. Hairy roots on hormonefree MS medium showed red spots in the older part of the tissues which turned white after a second subculture. Whereas hairy roots cultured on RC medium showed faster growth and produced large amount of Shikonin. The Shikonin content in transformed hairy root culture was estimated by recording absorbance at 620 nm and quantified against authentic sample of Shikonin. Shikonin content was estimated to be 0.85 mg g⁻¹ fresh weight of tissue at the end of the 50 days of culture. The results presented herein will help to design strategies for bridging the gap between ever increasing demand and supply of raw products necessary for obtaining Shikonin for cosmetic, dyeing, food, medicinal, and pharmaceutical industries.     

Frequency of group A rotavirus with mixed G and P genotypes in bovines: predominance of G3 genotype and its emergence in combination with G8/G10 types

The present study describes the genotypic distribution of rotaviruses (RVs) in an Indian bovine population with unexpectedly higher proportions of G3 alone or in combination of G8/G10. PCR-genotyping confirmed that 39.4% (13/33) of the prevalent RVs were the G3 type while 60.6% (20/33) were dual G3G10 or G3G8 types. P typing revealed that 93.9% (31/33) of the samples were P[11] while 6.1% (2/33) possessed a dual P[1]P[11] type. Sequence analysis of the VP7 gene from G3 strains viz. B-46, 0970, and BR-133 showed that these strains had sequence identities of 90.5% to 100% with other bovine G3 strains. The highest identity (98.9% to 100%) was observed with RUBV3 bovine G3 strains from eastern India. The G3 strains (B-46, 0970, and BR-133) showed 97.5% to 98.8% sequence homologies with the Indian equine RV strain Erv-80. Phylogenetic analysis demonstrated that G3 strains clustered with bovine RUBV3 and J-63, and equine Erv-80 G3. Overall, these results confirmed that the incidence of infection by RVs with the G3 genotype and mixed genotypes in the bovine population was higher than previously predicted. This finding reinforces the importance of constantly monitoring circulating viral strains with the G3 genotype in future surveillance studies.     

Survival of two avian respiratory viruses on porous and nonporous surfaces

The transmission of pathogens from infected to susceptible hosts may occur through contaminated fomites and inanimate objects. This type of transmission depends on the ability of the pathogens to survive in the environment. In this report, we describe the survivability of two avian respiratory viruses, e.g., avian metapneumovirus and avian influenza virus on 12 different porous and nonporous surfaces. The viruses survived on some of the surfaces for up to 6 days postcontamination but not after 9 days. Both viruses survived longer on nonporous surfaces than on porous ones. One of the reasons for poor survival on porous surfaces could be inefficient elution of virus from these surfaces. These results should be helpful in determining how long the premises should be left vacant after an outbreak of these viruses has occurred in poultry houses.