Antibiosis Activity Research Articles

Jakaba Undercover: Taxonomic Riddle and Potency in Indonesian Agriculture

Excessive use of chemical fertilizers leads to serious environmental and health issues, while organic biofertilizers offer a sustainable solution. <em>Jakaba</em> or “<em>jamur keberuntungan abadi</em>,” a local liquid organic fertilizer derived from fungi, is increasingly used by Indonesian farmers. However, its taxonomy and potential applications require further investigation. Moreover, the effects of <em>jakaba</em> on <em>Fusarium</em> and its impact on maize growth remain unexplored. This study aims to characterize <em>jakaba </em>comprehensively, evaluate its anti-<em>Fusarium</em> properties, conduct pathogenicity tests, and assess its effects on maize growth. Morphological analysis of fresh <em>jakaba</em> fruiting bodies was conducted, and molecular identification was performed based on the internal transcribed spacer (ITS) 1/4 regions. The antagonistic test was done using plant pathogenic fungi (<em>Fusarium </em>sp.). In addition, <em>jakaba </em>was evaluated for its impact on the vegetative growth of maize<em>. </em>Observations identified <em>jakaba</em> as belonging to the genus <em>Corallomycetella</em>, characterized by coral-shaped fruiting bodies with an orange hue and a white tip. The hyphae are septate, spore hyaline, and ellipsoid. The Basic Local Alignment Search Tool (BLAST) analysis revealed that <em>jakaba</em> was <em>Corallomycetella repens</em>, with a query cover of 99% and a phylogenetic tree 96% bootstrap (BS) value. <em>Jakaba</em> exhibits antibiosis activity against <em>Fusarium</em> sp., with an inhibition rate of 5.64%. Although <em>C. repens</em> has been previously identified as a cause of root rot in Indonesia, the current study reveals that <em>jakaba</em> is not pathogenic to maize. Furthermore, the application of <em>jakaba</em>’s liquid organic fertilizer at a concentration of 40 ml l<sup>-1</sup> significantly increased plant height, leaf length, leaf width, and stem diameter compared to other treatments. These findings highlight <em>jakaba</em> potential as a biofertilizer.

GC-MS analysis of hospital waste soil and isolation of antimicrobial agent producing bacteria

The current study, deals with the GC-Mass analysis of soil and antibiosis activity of soil bacteria, isolated from district hospital at Kabir Chaura, Varanasi, India. Standard serial dilution plate procedures were used to isolate the bacteria. Gram staining was used to identify the isolates morphologically. Strain KC14 was Gram-negative and all other isolates were Gram-positive. Isolated bacteria were tested against six human pathogens viz., Escherichia coli, Pseudomonas aeruginosa, Salmonella typhi, Staphylococcus aureus, Shigella flexneri and Bacillus subtilis. Primary and secondary screening were done by perpendicular streaking and seed overlay techniques. Based on the results most potential isolates were selected for tertiary screening. The GC-MS of soil samples revealed some major medical pollutants such as para-hydroxy acetanilide, 2-methyl-5-nitro-imidazole and 2-acetoxybenzoic acid. The KC14 isolate was chosen for further studies after demonstrating positive results against S. aureus with a maximum antagonistic activity of 17.3 ± 0.5 zone of inhibition. The molecular identification of KC14 isolate was determined by using 16S rRNA sequencing. The obtained nucleotide sequences were subjected to BLASTN in NCBI, and found similar to the available sequence of Acinetobacter junii. The nucleotide sequences have been deposited in GenBank with accession no. OP265396. The active compound was partially purified by ethyl acetate and tested its activity against S. aureus. This study defines the composition of hospital waste soil and identified a Gram-negative bacterium producing antibacterial activity against important human pathogens.

DIAGNOSIS OF Fusarium oxysporum FUNGUS ISOLATIONS AND Bacillus BACTERIA THE OF EFFICIENCY THE OF EVALUATION OF INHIBITION THE IN PHOSPHATE POTASSIUM AND subtili

The study aimed to isolate and diagnose types of Fusarium oxysporum from the roots of cucumbers and melons plants infected , from the fields of Al- Ssaouira, Al-Numaniya and Al-Hai in Wasit Governorate , and the possibility to control it by using the bacteria Bacillus subtilis and potassium phosphate concentration (500) mg / liter of water. Were obtained on (19) pure isolates of fungus F.oxysporum f.sp. cucumerinum and (11) pure isolates of F.oxysporum f.sp. melonis . The isolate F.oxysporum f.sp. cucumerinum (FOS 9) showed a high virulence than the rest isolates , white the isolates F.oxysporum f.sp. melonis (FOM 2) showed a high virulence than the rest isolates . The bacteria B.subtilis showed high antibiosis activity against F. oxysporum f.sp. cucumerinum and F.oxysporum f.sp. melonis and recorded (87.0%) and (92.5%) respectively.

A study on the potential of Bacillus thuringiensis AK08 to control pathogenic fungi associated with chili plant

Colletotrichum sp. and Fusarium sp. are significant fungal plant pathogen that affect chili plants. Various techniques are employed to manage the plant pathogens, including the application of biological agents such as Bacillus thuringiensis (Bt). This study aims to evaluate the efficacy of Bt AK08 in managing Colletotrichum sp. and Fusarium sp. Bt AK08 was subjected to dual-culturing experiments with the pathogens individually. Positive controls were employed in this study, consisting of Colletotrichum sp. and Fusarium sp. that were cultivated separately on pure potato dextrose agar. Propineb supplemented growth medium was serves as a negative control. The study involved the assessment of colony diameter of Colletotrichum sp. and Fusarium sp., as well as the evaluation of the antagonism activity exhibited by Bt AK08 through antibiosis activity and hyphal lysis. The findings indicated that Bt AK08 did not exhibit any antibiosis action since it did not result in a reduction in the colony diameter of the plant pathogenic fungus. However, we observed the breakdown of the hypha of the fungi. The present discovery suggests that Bt AK08 has promise as a potential agent for the management of Colletotrichum sp. and Fusarium sp. Hence, additional investigation is necessary to maximize its potential.

Potential of Endophytic Bacteria in Controlling The Red Jabon Leaf Spot Pathogens In Vitro

Plant pathogens pose a significant challenge to the cultivation of red Jabon (Anthocephalus macrophyllus) seedlings. Notably, the fungi Rhizoctonia sp. and Pestalotia sp. are responsible for the destructive red leaf spot disease on Jabon leaves. To combat these fungal pathogens, the use of endophytic bacteria has emerged as a potential alternative. Endophytic bacteria can be isolated from various plant sources, although their effectiveness in controlling forest plant pathogens like Jabon has not been thoroughly explored. This study aimed to assess the potential of endophytic bacterial isolates obtained from Pteris ensiformis (Isolates APE15, APE22, APE33, and APE35) in controlling the growth of Rhizoctonia sp. and Pestalotia sp. through in vitro experiments. The antibiosis activity of the endophytic bacteria against the pathogenic fungi was evaluated using the dual culture method on PDA media. The results revealed that among the four endophytic bacterial isolates, APE35 exhibited the highest inhibitory effect on Rhizoctonia sp. (86.79%) and Pestalotia sp. (67.5%), while isolate APE22 only inhibited the growth of Pestalotia sp. (55%). In contrast, isolates APE15 and APE33 were unable to suppress either fungus. The antibiosis activity of APE35 and APE22 resulted in abnormal hyphal growth of the pathogenic fungi, characterized by shriveled, bent, dark-colored, and coiled hyphae. Physiological characterization of the endophytic bacteria revealed their ability to produce protease, cellulase, catalase, and phosphate-dissolving enzymes. Additionally, these bacteria exhibited a Gram-positive nature. This study provides valuable insights into the potential of endophytic bacterial isolates from P. ensiformis (APE35 and APE22) as biological control agents for Rhizoctonia sp. and Pestalotia sp., the causative agents of red Jabon leaf spot disease.

Molecular interaction between plants and Trichoderma species against soil-borne plant pathogens.

Trichoderma spp. (Hypocreales) are used worldwide as a lucrative biocontrol agent. The interactions of Trichoderma spp. with host plants and pathogens at a molecular level are important in understanding the various mechanisms adopted by the fungus to attain a close relationship with their plant host through superior antifungal/antimicrobial activity. When working in synchrony, mycoparasitism, antibiosis, competition, and the induction of a systemic acquired resistance (SAR)-like response are considered key factors in deciding the biocontrol potential of Trichoderma. Sucrose-rich root exudates of the host plant attract Trichoderma. The soluble secretome of Trichoderma plays a significant role in attachment to and penetration and colonization of plant roots, as well as modulating the mycoparasitic and antibiosis activity of Trichoderma. This review aims to gather information on how Trichoderma interacts with host plants and its role as a biocontrol agent of soil-borne phytopathogens, and to give a comprehensive account of the diverse molecular aspects of this interaction.

Comprehensive genomic analysis of Bacillus paralicheniformis strain BP9, pan-genomic and genetic basis of biocontrol mechanism

Many Bacillus species are essential antibacterial agents, but their antibiosis potential still needs to be elucidated to its full extent. Here, we isolated a soil bacterium, BP9, which has significant antibiosis activity against fungal and bacterial pathogens. BP9 improved the growth of wheat seedlings via active colonization and demonstrated effective biofilm and swarming activity. BP9 sequenced genome contains 4282 genes with a mean G-C content of 45.94% of the whole genome. A single copy concatenated 802 core genes of 28 genomes, and their calculated average nucleotide identity (ANI) discriminated the strain BP9 from Bacillus licheniformis and classified it as Bacillus paralicheniformis. Furthermore, a comparative pan-genome analysis of 40 B. paralicheniformis strains suggested that the genetic repertoire of BP9 belongs to open-type genome species. A comparative analysis of a pan-genome dataset using the Kyoto Encyclopedia of Genes and Genomes (KEGG) and Cluster of Orthologous Gene groups (COG) revealed the diversity of secondary metabolic pathways, where BP9 distinguishes itself by exhibiting a greater prevalence of loci associated with the metabolism and transportation of organic and inorganic substances, carbohydrate and amino acid for effective inhabitation in diverse environments. The primary secondary metabolites and their genes involved in synthesizing bacillibactin, fencing, bacitracin, and lantibiotics were identified as acquired through a recent Horizontal gene transfer (HGT) event, which contributes to a significant part of the strain`s antimicrobial potential. Finally, we report some genes essential for plant-host interaction identified in BP9, which reduce spore germination and virulence of multiple fungal and bacterial species. The effective colonization, diverse predicted metabolic pathways and secondary metabolites (antibiotics) suggest testing the suitability of strain BP9 as a potential bio-preparation in agricultural fields.

Excellent photocatalytic degradation and antibiosis of WO3/Fe2O3 heterojunction

The extensive light absorption, enhanced separation of photoinduced carriers and convenience of recycling are crucial for the practical application of WO3 photocatalyst in the dye degradation and the antibiosis activity. Hence, in this work, we synthesize WO3/Fe2O3 composite film on FTO conductive substrate through hydrothermal method. The higher degradation rate for methylene blue (MB) is achieved by WO3/Fe2O3 composite film, and the value of C/C0 is 0.28 which is lower than that of 0.58 for bare WO3 with the irradiation for 4 h. Moreover, the sterilization rate of 28.99% is achieved for WO3-based film with the deposition of Fe2O3 for 3 h. The deeper measurements indicate that the enhanced photocatalytic performances are attributed to the expand light absorption, improved transfer kinetics and separation efficiency of photoinduced carriers with the formation of heterojunction. This work establishes the effective template for WO3-based film with the enhanced photocatalytic prosperities for dye degradation and antibiosis.

ISOLATION, CHARACTERIZATION AND IDENTIFICATION OF MULTIFACETED HALOTOLERANT BACILLUS LICHENIFORMIS AND BACILLUS WUDALIANCHIENSIS FROM RHIZOSPHERIC SOILS OF BANGALORE

Plant growth promotion through versatile microorganisms inhabiting the rhizospheric region of the soil has emerged as a sustainable approach in improving the crop productivity and crop health management. The present study reports the isolation and characterization of halotolerant as well as drought tolerant isolates that possess exceptional plant growth promotional attributes. Out of 32 isolates obtained, 13 isolates exhibited excellent plant growth promotional attributes such as phosphate solubilization, phytohormone production, siderophore production etc. Among 13 isolates tested for stress tolerance studies, two isolates Mulberry -1 and Ragi-7 were able to tolerate both drought and saline stresses and were further identified as Bacillus licheniformis and Bacillus wudalianchiensis based on biochemical and molecular techniques. Antibiosis activity of both the isolates tested against two important plant pathogens Fusarium oxysporum and Phomopsis vexans was found to be positive. Bacillus licheniformis and Bacillus wudalianchiensis were further tested for their efficacy to solubilize five different inorganic phosphate sources. The amount of phosphate liberated was found to be highest (3562 mgml-1 and 1894 mgml-1) with diammonium phosphate followed by single super phosphate and tricalcium phosphate with respect to Bacillus licheniformis and Bacillus wudalianchiensis. Zea mays L. seeds treated with the culture filtrate of both the isolates were cultivated on Murashige-Skoog medium under In-vitro conditions. Bacillus wudalianchiensis was found to be better compared to Bacillus licheniformis with respect to plant growth promotional aspects as they were able to increase the root and shoot length of Zea mays L. under In-vitro conditions. Application of the multifaceted capabilities of unexplored halotolerant strain of Bacillus wudalianchiensis could open up a new avenue in plant biotechnology.

Research Progress on Antibiosis Activity of Scutellaria Flavonoids

Scutellariae (Huangqin) is a traditional medicine that is widely applied in China for the treatment of cold and fever, and nowadays research found that it can against pathogenic microorganism. Flavonoids is the main active constituent isolated from Scutellariae and possesses outstanding antibiosis activity. Scutellaria flavonoids displayed antiseptic actions and anti-resistance, including but not limited to destroy bacterial biofilm, suppressed activity of the DNA enzyme, restrain efflux pump and quorum-sensing system. This paper highlights and discusses the antibiosis activity of Scutellaria flavonoids, along with possible mechanisms of its action. hoping to providing basis and evidence for clinical application.

Antifungal and antibacterial activity of the floral ethanolic extract of Mandevilla pohliana (Stadelm.) A. H. Gentry

Mandevilla pohliana is a species belonging to the Apocynaceae family found in Cerrado environments. The bjetive of this study was to evaluate the antifungal and antibacterial action of the floral ethanolic extract of M. pohliana. Flowers of M. pohliana were collected and the ethanolic extract produced by maceration. In different concentrations of extract, antifungal of the genus Candida were determined, and antibacterial activities on Escherichia, Salmonella, Enterococcus, Pseudomonas and Staphylococcus. Antibiosis activity was observed only for C. guilliermondii with 9-2 mm, for P. aeruginosa with 12-3 mm and for E. faecalis between 10-3 mm at the highest concentrations between 50-500 mg mL-1. The floral ethanolic extract of Mandevilla pohliana showed potential as a natural antifungal and antibacterial agent.

Epiphytic yeasts from Piperaceae as biocontrol agents for foot rot of black pepper caused by Phytophthora capsici

Abstract. Safitri D, Wiyono S, Soekarno BPW, Achmad. 2021. Epiphytic yeasts from Piperaceae as biocontrol agents for foot rot of black pepper caused by Phytophthora capsici. Biodiversitas 22: 1895-1901. Phytophthora capsici, is a causative agent of footrot disease, is the primary pathogen in black pepper (Piper nigrum L.). Footrot disease may cause a loss of 67% black pepper production. Yeast as a biocontrol is a promising technique to control foot rot disease. This study aimed to isolate, characterize yeasts from several species of Piper and determine their effectiveness against foot rot disease. Epiphytic yeasts were isolated from roots, stems, and leaves of Piper nigrum, P. retrofractum, and P. ornatum. The epiphytic yeasts were tested for their antagonistic activity against P. capsici as biocontrol agents. The antagonistic activity was observed through antibiosis mechanisms, volatile organic compound production, hyperparasitism, and the production of ?1-1,3 glucanase enzyme. A total of 48 epiphytic yeasts were isolated from Piper species. There were five isolates with high antibiosis activity in vitro, i.e. EPT23, E62, EPT63, EPT69, EPT70, and identified through molecular identification as Rhodotorula glutinis, Cryptococcus magnus, Filobasidium globisporum, R. mucilaginosa, H. oryzae, respectively. The selected yeast showed biocontrol activity against foot rot disease ranged from 56.7 to 80.0%.

Caecal microbiota compositions from 7-day-old chicks reared in high-performance and low-performance industrial farms and systematic culturomics to select strains with anti-Campylobacter activity.

There is growing interest in exploring the chickens' intestinal microbiota and understanding its interactions with the host. The objective is to optimize this parameter in order to increase the productivity of farm animals. With the goal to isolate candidate probiotic strains, specific culturomic methods were used in our study to culture commensal bacteria from 7-days old chicks raised in two farms presenting long history of high performance. A total of 347 isolates were cultured, corresponding to at least 64 species. Among the isolates affiliated to the Firmicutes, 26 had less than 97% identity of their partial 16S sequence with that of the closest described species, while one presented less than 93% identity, thus revealing a significant potential for new species in this ecosystem. In parallel, and in order to better understand the differences between the microbiota of high-performing and low-performing animals, caecal contents of animals collected from these two farms and from a third farm with long history of low performance were collected and sequenced. This compositional analysis revealed an enrichment of Faecalibacterium-and Campylobacter-related sequences in lower-performing animals whereas there was a higher abundance of enterobacteria-related sequences in high-performing animals. We then investigated antibiosis activity against C. jejuni ATCC 700819 and C. jejuni field isolate as a first phenotypic trait to select probiotic candidates. Antibiosis was found to be limited to a few strains, including several lactic acid bacteria, a strain of Bacillus horneckiae and a strain of Escherichia coli. The antagonist activity depended on test conditions that mimicked the evolution of the intestinal environment of the chicken during its lifetime, i.e. temperature (37°C or 42°C) and oxygen levels (aerobic or anaerobic conditions). This should be taken into account according to the stage of development of the animal at which administration of the active strain is envisaged.

Siderophore and indolic acid production by Paenibacillus triticisoli BJ-18 and their plant growth-promoting and antimicrobe abilities.

Paenibacillus triticisoli BJ-18, a N2-fixing bacterium, is able to promote plant growth, but the secondary metabolites that may play a role in promoting plant growth have never been characterized. In this study, untargeted metabolomics profiling of P. triticisoli BJ-18 indicated the existence of 101 known compounds, including N2-acetyl ornithine, which is the precursor of siderophores, plant growth regulators such as trehalose 6-phosphate, betaine and trigonelline, and other bioactive molecules such as oxymatrine, diosmetin, luotonin A, (-)-caryophyllene oxide and tetrahydrocurcumin. In addition, six compounds were also isolated from P. triticisoli BJ-18 using a combination of silica gel chromatography, sephadex LH-20, octadecyl silane (ODS), and high-performance liquid chromatography (HPLC). The compound structures were further analyzed by Nuclear Magnetic Resonance (NMR), Mass Spectrometry (MS), and Electronic Circular Dichroism (ECD). The six compounds included three classical siderophore fusarinines identified as deshydroxylferritriacetylfusigen, desferritriacetylfusigen, and triacetylfusigen, and three indolic acids identified as paenibacillic acid A, 3-indoleacetic acid (IAA), and 3-indolepropionic acid (IPA). Both deshydroxylferritriacetylfusigen and paenibacillic acid A have new structures. Fusarinines, which normally occur in fungi, were isolated from bacterium for the first time in this study. Both siderophores (compounds 1 and 2) showed antimicrobial activity against Escherichia coli, Staphylococcus aureus and Bacillus subtilis, but did not show obvious inhibitory activity against yeast Candida albicans, whereas triacetylfusigen (compound 3) showed no antibiosis activity against these test microorganisms. Paenibacillic acid A, IAA, and IPA were shown to promote the growth of plant shoots and roots, and paenibacillic acid A also showed antimicrobial activity against S. aureus. Our study demonstrates that siderophores and indolic acids may play an important role in plant growth promotion by P. triticisoli BJ-18.

Bacillus subtilis Strains Isolated from Cocoa Trees (Theobroma cacao L.) Rhizosphere for their use as Potential Plant Growth Promoting Rhizobacteria in Côte d'Ivoire.

Plant growth promoting rhizobacteria (PGPR) are important for agriculture through their activity in stimulating and facilitating plant growth. The rhizobacteria were screened for molecular characterization and followed by their indole acetic acid (IAA) production, phosphate solubility, antibiosis activity. In this study, 162 soil samples were collected from the cocoa rhizosphere to isolate Bacillus subtilis strains using Mössel agar medium with an additional egg yolk and identified by sequencing the ytcP gene. The ability of each strain to form biofilms was obtained in a tube. Indole-3-acetic acid (IAA) production was estimated in Yeast Peptone Dextrose (YPB) broth. Phosphates were solubilized by each strain on Pikovskaya agar medium. The detection of lipopeptide genes using the molecular method has established the possession of isolates by antimicrobial genes. Fifty (50) B. subtilis strains were isolated and identified using the ytcP gene. Ninety percent (90%) of the strains were able to form a biofilm. All isolates produced an IAA. Forty (40 (80%)) of B. subtilis were solubilized phosphate with phosphate solubilizing index (PSI) of 0 to 97.33 ± 0.70%. Of all B. subtilis strains, 45 (90%) have the srfAA gene, 19 (38%) have the fenD gene and 12 (24%) have the ituC gene. B. subtilis strains from cocoa rhizosphere would be beneficial for agricultural production by their PGPR activities.

Antibiosis Effects of Rice Carrying Bph14 and Bph15 on the Brown Planthopper, Nilaparvata lugens

The brown planthopper(BPH), Nilaparvata lugens, is the most destructive insect pest in rice production worldwide. The development and cultivation of BPH-resistant varieties is the most economical and efficient strategy to overcome the destruction caused by BPH. The modified bulk seedling test method was used to identify the BPH resistance level and host feeding choice of rice lines of Liangyou8676(Bph14/Bph15), Bph68S(Bph14/Bph15), RHT(Bph3), Fuhui676, and TN1 on BPH. In the meantime, the population, survival and emergence rate, developmental duration, honeydew excretion, female ratio and brachypterous ratio of adults were used as indicators to detect the antibiosis effects of the different rice lines. The results showed that the resistance levels of RHT, Bph68S, Liangyou8676, Fuhui676, and TN1 to BPH were HR, R, MR, S and HS, respectively. The host choice implied that BPH was more inclined to feeding on rice plants with a lower resistance. An analysis of the antibiosis activity of rice lines RHT, BPh68S, and Liangyou8676 carrying resistance genes indicated a significant reduction in the population growth rate, survival and emergence rate of BPH nymphs, significant delay in the developmental duration of nymphs, reduced honeydew excretion of females, decreased female ratio, and a decreased brachypterous ratio of females and males, when compared with rice carrying no BPH-resistant genes.

Eksplorasi dan Karakterisasi Bakteri Agens Hayati dari Imperata cylindrica untuk pengendalian Rigidoporus microporus

Exploration and Characterization of Biological Agents Bacteria from Imperata cylindrica for Controlling Rigidoporus microporusWhite root disease caused by Rigidoporus microporus is an important disease in rubber plantation. This pathogen causes damage to roots, thus adversely affect plant growth and productivity of rubber plantation. Therefore controling of this pathogen is important to do. The objective of this research was to obtain biological agents bacteria from the various parts of alang-alang (Imperata cylindrica) which have inhibitory activity against the growth of R. microporus The research was conducted through exploration of biological agents from the various parts of alang-alang, antibiosis activity test, and characterization of potential isolates. Based on antibiosis activity test, seven isolates (Rph 7, Rph 8, Rph 15 Rph 17, 15, E47, and isolate 47) showed antibiosis activity against R. microporus. Suppression activity of R. microporus growth by seventh of potential isolates ranged between 26.7-58.9%. The highest inhibition was demonstrated by isolate 47 suspected leaf endophytic bacteria. Seventh of potential isolates are Gram-positive bacterial that can form spores. The biological agen’s bacterial dominated by isolates from the reeds rhizosphere. This result indicates that rhizosphere is a potentialy source in the exploration of biological agents. In addition, R. microporus is a soil-borne pathogen which colonizes the roots therefore exploration from rhizosphere samples allows obtaining potential biological agents.

Screening of fungal contaminants in banana tissue cultures in Jkuat, Kenya

Tissue culture is prone to high costs of production arising from losses incurred from fungal contamination. The aim of the study was to characterise fungal contaminants and elucidate the exhibited mode of resistance to most preferred sterilants. Twenty nine fungal samples were collected at the different stages of tissue culture growth, using purposive sampling technique. Morphology results were confirmed by molecular characterization using fungal 18S rRNA sequences. Biochemical and antibiosis tests, identification of genes for capsulation and ATP binding Cassete (ABC) transporters, were performed to show the relationship between the fungi and sterilants resistance. Amylases and proteases were highly expressed by all isolates while xylanases and lipases were moderately expressed and esterases were lowly expressed. Only fourteen isolates had antagonistic activity for Candida albicans while nine of them had antagonistic activity for Pseudomonas aeruginosa. Three isolates were both antagonistic for Staphylococcus aureus and for Escherichia coli. Cunninghamella bainieri (10R) recorded a unique antibiosis and extra cellular enzymatic activity (p<0.05). All the isolates were positive for mdr1 gene and three isolates had CAP64 capsule genes. Aspergillus sp., Penincillium sp., Cladosporium sp., Cunninghamella sp. and Fusarium sp. were identified to be the major fungal contaminants of tissue culture banana cultures in JKUAT laboratories. Key words: Tissue culture, 18S rRNA, fungal contaminants, banana cultures.

Growth and metabolic characterization of four lactic acid bacteria species isolated from rice beer prepared in Assam, India.

Isolation and identification of lactic acid bacteria (LAB) from rice beer prepared in Assam, India was performed and their growth associated and functional properties were studied. LAB strains were identified as Lactobacillus casei , Pediococcus pentosaceus , Lactobacillus pentosus and Lactobacillus plantarum based on 16 s rRNA sequencing. Their growth characteristics at different pH, NaCl concentration, temperature and presence of carbohydrates were profiled. High tolerance against acid and bile salts was shown by all the strains, particularly L. pentosus TEZU174 and P. pentosaceus TEZU199 up to a pH of 1.5, and L. pentosus TEZU174 up to 14 % bile concentration. They were susceptible towards the common antibiotics, wherein erythromycin, chloramphenicol and linezolid were the most effective. The strains displayed antibiosis activity against Escherichia coli and Staphylococcus aureus and antioxidant activity in terms of resistance to H2O2, scavenging of ·OH and DPPH free radicals was also displayed, wherein L. casei TEZU374 and P. pentosaceus TEZU482 were the most effective with above 70 % scavenging activity. The strains displayed cellular aggregation and L. casei TEZU262 and L. casei TEZU309 were highly aggregated, which attained 100 % autoaggregation within a period of 5 h. High cell surface hydrophobicity was shown by L. casei TEZU309 towards xylene and chloroform, and P. pentosaceus TEZU427 towards ethyl acetate. The strains evinced good gut tolerance capacity, antioxidant activity and adherence properties, which are characteristics of probiotic bacteria and thus are candidates for therapeutic uses and also to be used as starter cultures.

Trichome and biochemical basis of resistance against Tuta absoluta in tomato genotypes

AbstractSouth American tomato moth, Tuta absoluta, a serious pest of tomato (Solanum lycopersicum) in tropics and subtropics, is rapidly spreading world over. Twenty one wild/cultivated/advanced breeding lines of tomato were screened for resistance to T. absoluta under greenhouse conditions (choice bioassay) and promising genotypes were evaluated further for their antibiosis activity through no choice bioassay under in-vitro conditions. From 21 genotypes screened, six wild accessions viz., S. pennellii (LA 1940); S. chilense (LA 1963); S. arcanum (LA 2157); S. lycopersicum (LA1257) and S. corneliomulleri (LA 1292, LA1274) were relatively resistant to T. absoluta based on mean percent damage and were further studied under in-vitro conditions. These genotypes recorded relatively more larval mortality, prolonged larval and pupal duration with reduced adult emergence of T. absoluta. Among these six genotypes, S. pennellii (LA-1940) showed resistance both under choice and no choice bioassays with higher number of type IV trichomes, highest total flavonoids and phenols. In general, glandular trichomes (GTs) (type I, IV, VII) showed negative correlation in different genotypes of tomato with reference to larval number/plant, percent damage and adult activity, whereas type V (non-GTs) showed negative correlation with number of larvae/plant.