Growth promotion of wheat seedlings by <Emphasis Type="Italic">Exiguobacterium acetylicum</Emphasis> 1P (MTCC 8707) a cold tolerant bacterial strain from the Uttarakhand Himalayas

Exiguobacterium acetylicum strain 1P (MTCC 8707) is a gram-positive, rod-shaped, yellow pigmented bacterium isolated from soil on nutrient agar plates at 4°C. The identity of the bacterium was arrived on the basis of the biochemical characterization, BIOLOG sugar utilization pattern and sequencing of the 16S rRNA gene. It grew at temperatures ranging from 4 to 42°C, with temperature optima at 30°C. It expressed multiple plant growth promotion attributes such as phosphate solubilization, indole acetic acid (IAA), siderophore and hydrogen cyanide (HCN) production, differentially at suboptimal growth temperatures (15 and 4°C). At 15°C it solubilized phosphate (21.1 μg of P ml⁻¹ day⁻¹), and produced IAA (14.9 μg ml⁻¹ day⁻¹) in tryptophan amended media. Qualitative detection of siderophore production and HCN were possible at 15°C. At 4°C it retained all the plant growth promotion attributes. Seed bacterization with the isolate, positively influenced the growth and nutrient uptake parameters of wheat seedlings in glass house studies at suboptimal cold growing temperatures.     

Potential plant growth-promoting activity of <Emphasis Type="Italic">Serratia nematodiphila</Emphasis> NII-0928 on black pepper (<Emphasis Type="Italic">Piper nigrum</Emphasis> L.)

A potential bacterial strain designated as NII-0928 isolated from Western ghat forest soil with multiple plant growth promoting attributes, and it has been identified and characterized. Plant growth promoting traits were analyzed by determining the P-solubilization efficiency, Indole acetic acid production, HCN, siderophore production and growth in nitrogen free medium. It was able to solubilize phosphate (76.6 μg ml⁻¹), and produce indole acetic acid (58.9 μg ml⁻¹) at 28 ± 2°C. Qualitative detection of siderophore production and HCN were also observed. At 5°C it was found to express all the plant growth promotion attributes except HCN production. The ability to colonize roots is a sine qua non condition for a rhizobacteria to be considered a true plant growth-promoting rhizobacteria (PGPR). 16S rRNA gene sequencing reveals the identity of the isolate as Serratia nematodiphila with which it shares highest sequence similarity (99.4%). Seed bacterization with black pepper cuttings in greenhouse trials using Sand: Soil: FYM with three individual experimental sets with their respective control showed clearly the growth promoting activity. Hence, Serratia nematodiphila NII-0928 is a promising plant growth promoting isolate showing multiple PGPR attributes that can significantly influence black pepper cuttings. The result of this study provides a strong basis for further development of this strain as a bioinoculants to attain the desired plant growth promoting activity in black pepper growing fields.     

Characterization of a cold-tolerant plant growth-promoting bacterium Pantoea dispersa 1A isolated from a sub-alpine soil in the North Western Indian Himalayas

Pantoea dispersa strain 1A is a Gram-negative rod-shaped, yellow-pigmented bacterium isolated on nutrient agar plates incubated at 4°C. The identity of the bacterium was confirmed by sequencing of the 16 S rRNA gene. It was capable of growing at temperatures ranging from 4 to 42°C, but maximum growth was observed at 30°C. It is endowed with multiple plant growth promotion attributes such as phosphate solubilization, IAA production, siderophore production and HCN production, which are expressed differentially at sub-optimal temperatures (15 and 4°C). It was able to solubilize phosphate (17.6 μg of P₂O₅ ml⁻¹ day⁻¹), and produce IAA (3.7 μg ml⁻¹ day⁻¹), at 15°C. Qualitative detection of siderophore production and HCN were also observed at 15°C. At 4°C it was found to express all the plant growth promotion attributes. This bacterial isolate was able to positively influence and promote the growth and nutrient uptake parameters of wheat (cv. VL.802) under glasshouse conditions. Hence in the context, of cold wheat-growing environments, it is proposed that Pantoea dispersa 1A (MTCC 8706), could be deployed as an inoculant to attain the desired results of bacterization.     

Molybdate reduction by Pseudomonas sp. strain DRY2

Aims: To isolate and characterize a potent molybdenum‐reducing bacterium. Methods and Results: A minimal salt medium supplemented with 10 mmol l^?1 molybdate, glucose (1·0%, w/v) as a carbon source and ammonium sulfate (0·3%, w/v) as a nitrogen source was used in the screening process. A molybdenum‐reducing bacterium was isolated and tentatively identified as Pseudomonas sp. strain DRY2 based on carbon utilization profiles using Biolog GN plates and partial 16S rDNA molecular phylogeny. Strain DRY2 produced 2·4, 3·2 and 6·2 times more molybdenum blue compared to Serratia marcescens strain DRY6, Enterobacter cloacae strain 48 and Eschericia coli K12, respectively. Molybdate reduction was optimum at 5 mmol l^?1 phosphate. The optimum molybdate concentration that supported molybdate reduction at 5 mmol l^?1 phosphate was between 15 and 25 mmol l^?1. Molybdate reduction was optimum at 40°C and at pH 6·0. Phosphate concentrations higher than 5 mmol l^?1 strongly inhibited molybdate reduction. Inhibitors of electron transport system such as antimycin A, rotenone, sodium azide and cyanide did not inhibit the molybdenum‐reducing enzyme activity. Chromium, copper, mercury and lead inhibited the molybdenum‐reducing activity. Conclusions: A novel molybdenum‐reducing bacterium with high molybdenum reduction capacity has been isolated. Significance and Impact of the Study: Molybdenum is an emerging global pollutant that is very toxic to ruminants. The characteristics of this bacterium suggest that it would be useful in the bioremediation of molybdenum pollutant.     

Entomopathogenicity of endophytic <Emphasis Type="Italic">Serratia marcescens</Emphasis> strain SRM against larvae of <Emphasis Type="Italic">Helicoverpa armigera</Emphasis> (Noctuidae: Lepidoptera)

An endophytic Serratia marcescens strain SRM (MTCC 8708) isolated from the flowers of summer squash was found to be entomopathogenic against the larvae of Helicoverpa armigera. Natural epizootic of this bacterial strain on the larvae collected from summer squash flowers ranged from 19.9 to 72.3%. Under laboratory conditions, a dose of 6 × 10¹⁰ c.f.u./ml diet induced 66.3% mortality of first instar H. armigera larvae. Similarly all other growth and development parameters of the insect were severely retarded in a dose-dependent manner. The bacterium invaded the entire alimentary canal and haemolymph with successful replacement of all other gut-associated microflora. There was a great reduction in midgut proteinase activity due to inhibition of five major proteinase isozymes by S. marcescens infection. Further, a synergistic interaction between chitinases isolated from this strain and Bacillus thuringiensis Cry1Ac toxin was observed. The present findings suggest that this plant-associated S. marcescens strain SRM could be suitably exploited for the management of H. armigera.     

Effect of incubation temperature on growth parameters of Pseudoalteromonas antarctica NF and its production of extracellular polymeric substancesdagger

Aim: To evaluate the effect of temperature on growth parameters and on extracellular polymeric substance (EPS) production for Pseudoalteromonas antarctica NF₃. Methods and Results: For this purpose, three growth parameters, lag time (λ), maximum growth rate (μ) and maximum population density (A), were calculated with the predictive Gompertz model. To evaluate the variations in μ with respect to temperature, the secondary Arrhenius and the square root models were used. Below the optimal growth temperature (17·5°C), the growth of P. antarctica was separated into two domains at the critical temperature of 12°C. Within the suboptimal domain (12–17·5°C), the temperature characteristic was the lowest (5·29 kcal mol^?1). Growth population densities were maintained over the entire physiological portion assayed (5–17·5°C). Higher crude EPS production was found at temperatures included in the cold domain (5–12°C). Conclusions: All calculated parameters revealed an optimal adaptation of this strain to cold temperatures. Significance and Impact of the Study: The knowledge of the influence of temperature on growth parameters of P. antarctica NF₃ and on EPS production could improve the production of this extracellular polymeric substance that is currently being used in the cosmetic and pharmaceutical industries.     

<Emphasis Type="Italic">Pseudomonas lurida</Emphasis> M2RH3 (MTCC 9245), a psychrotolerant bacterium from the Uttarakhand Himalayas,solubilizes phosphate and promotes wheat seedling growth

Pseudomonas lurida strain M2RH3 (MTCC 9245) is a Gram negative, non spore forming, fluorescent bacterium isolated from a high altitude rhizospheric soil from the Uttarakhand Himalayas. The identity of the bacterium was arrived by sequencing of the 16S rRNA gene and subsequent phylogenetic analysis. It grew and exhibited plant growth promoting traits at 4, 15 and 30°C, under in vitro conditions. The expression of plant growth promoting (PGP) traits by the bacterium was highest at 30°C, with a proportionate reduction in PGP activity at lower temperatures. Determination of phosphate solubilization by the bacterium at three incubation temperatures revealed a steady increase in the soluble P levels across the incubation temperatures, coupled with a concomitant drop in the pH levels of the culture supernatant, till the 14th day of incubation. Seed bacterization with the isolate positively influenced the growth and nutrient uptake parameters of wheat seedlings cv. VL 804 in pot culture conditions at controlled cold growing temperature. This is an early report on the phosphate solubilization and plant growth promotion by Pseudomonas lurida, which is a relatively new species of the genus Pseudomonas and opens up a hitherto unknown facet of this bacterium.     

Plant growth promoting potentials of Pseudomonas spp. strain OG isolated from marine water

Abstract

Bacterium Pseudomonas spp. olive green (OG) was isolated from marine water, yet, it was characterized as plant growth promoting bacterium (PGPB). Multiple plant growth promoting traits of OG isolate were determined in vitro. It was tested positive for Indole-3-acetic acid (IAA) production with 29 µg ml^?1 of IAA yield, phosphate solubilization with 34 µg ml^?1 solubilization of Tri-calcium-phosphate and it showed maximum of 32 µg ml^?1 of ammonia production. OG isolate was affirming siderophore production, hydrocyanic acid (HCN) production and catalase production. 16S rRNA gene sequence comparison was used to identify the isolate which showed its closest neighbor to be Pseudomonas fluoroscens strain BCPBMS-1. Efficacy of this PGPB was tested on the seedling growth of two test plants chickpea and green gram. Both the test plants treated with OG-based talc bioformulation showed significant growth promotion. Chickpea showed enhanced overall fresh biomass by 24%, overall dry biomass by 27% was observed after 15 days of seeded in pots. Green gram showed enhanced overall dry biomass by 28% was observed after 10 days of seeded in pots.     

Environmental Optima for Seven Strains of Pseudochattonella (Dictyochophyceae,Heterokonta)

The ichthyotoxic flagellate Pseudochattonella has formed recurrent blooms in the North Sea, Skagerrak and Kattegat since 1998. Five strains of Pseudochattonella farcimen and two strains of P. verruculosa were examined in an assay comparing the light response of specific growth rates over a range of temperatures and salinities to get further knowledge on the autecology of members of this genus. Temperature optima were lower in P. farcimen (9°C–15°C) than in P. verruculosa (12°C–20°C). P. farcimen also showed a somewhat lower salinity optimum (18–26) than P. verruculosa (20–32). All strains showed light‐dependent growth responses reaching saturation between 18 and 52 μmol · photons · m^?2 · s^?1 at optimal temperature and salinity conditions. Compensation point estimates ranged from 4.2 to 15 μmol · photons · m^?2 · s^?1. Loss rates increased with temperature and were lowest at salinities close to optimal growth conditions. Blooms of P. farcimen have been recorded in nature under conditions more similar to those minimizing loss rates rather than those maximizing growth rates in our culture study.     

Isolation and characterization of butachlor‐catabolizing bacterial strain Stenotrophomonas acidaminiphila JS‐1 from soil and assessment of its biodegradation potential

Aims: Isolation, characterization and assessment of butachlor‐degrading potential of bacterial strain JS‐1 in soil. Methods and Results: Butachlor‐degrading bacteria were isolated using enrichment culture technique. The morphological, biochemical and genetic characteristics based on 16S rDNA sequence homology and phylogenetic analysis confirmed the isolate as Stenotrophomonas acidaminiphila strain JS‐1. The strain JS‐1 exhibited substantial growth in M9 mineral salt medium supplemented with 3·2 mmol l^?1 butachlor, as a sole source of carbon and energy. The HPLC analysis revealed almost complete disappearance of butachlor within 20 days in soil at a rate constant of 0·17 day^?1 and half‐life (t_½) of 4·0 days, following the first‐order rate kinetics. The strain JS‐1 in stationary phase of culture also produced 21·0 μg ml^?1 of growth hormone indole acetic acid (IAA) in the presence of 500 μg ml^?1 of tryptophan. The IAA production was stimulated at lower concentrations of butachlor, whereas higher concentrations above 0·8 mmol l^?1 were found inhibitory. Conclusions: The isolate JS‐1 characterized as Stenotrophomonas acidaminiphila was capable of utilizing butachlor as sole source of carbon and energy. Besides being an efficient butachlor degrader, it substantially produces IAA. Significance and Impact of the Study: The bacterial strain JS‐1 has a potential for butachlor remediation with a distinctive auxiliary attribute of plant growth stimulation.     

Characterization of plant growth-promoting rhizobacterium <Emphasis Type="Italic">Exiguobacterium</Emphasis> NII-0906 for its growth promotion of cowpea (<Emphasis Type="Italic">Vigna unguiculata</Emphasis>)

A phosphate solubilizing and antagonistic bacterial strain, isolated from a Western Ghat forest soil in Kerala province, India (designated as NII-0906), showed cold tolerance and grew from 10 to 37°C (optimum temperature 30°C). It was a Gram-positive, rod shaped, 0.8–1.6 μm in size, and exhibited tolerance to a wide pH range (5–12; optimum 7.0) and salt concentration up to 7% (w/v). The isolate showed maximum similarity with Exiguobacterium marinum TF-80^T based on 16S rRNA analysis. It solubilized tricalcium phosphate under in vitro conditions. The phosphate solubilization was estimated along a temperature range (5–40°C), and maximum activity (84.7 μg mL⁻¹ day⁻¹) was recorded at 30°C after 10 days of incubation. The phosphate solubilizing activity coincided with a concomitant decrease in pH of the medium. The isolate also exhibited antifungal activity against phytopathogenic fungi in Petri dish assays and produced siderophore and hydrogen cyanide. The strain’s plant growth promotion properties were demonstrated through a cowpea-based bioassay under greenhouse conditions. The bacterial inoculation resulted in significant increment in plant root, stem and as well as in plant biomass. Further, scanning electron microscopic study revealed the root colonization in cowpea. These results could offer potential perspective for the strain to be used as plant growth-promoting rhizobacteria, which could be used as an inoculant for regional crops.     

Delineating Kocuria turfanensis 2M4 as a credible PGPR: a novel IAA-producing bacteria isolated from saline desert

Indole-3-acetic acid (IAA)-producing bacteria Kocuria turfanensis strain 2M4 was isolated from the rhizospheric soil of halotolerant plant Suaeda fruticosa from a unique saline desert of Little Rann of Kutch, Gujarat, India. Rhizobacteria was bright orange pigmented, gram-positive, coccoid, non-endospore forming, and aerobic in nature. 16S rRNA gene sequence analysis showed that 2M4 isolate matched best with type strain of K. turfanensis HO-9042^T. Isolate optimally produced 38 µg ml^?1 IAA when growth medium was supplemented with 600 µg ml^?1 of L-tryptophan. Thin layer chromatography and Fourier transform infrared spectroscopy analysis were performed to corroborate IAA production. To characterize rhizobacterial isolate as a plant growth-promoting bacteria, it was tested for phosphate solubilization where it solubilized maximum 12 µg ml^?1 phosphate in presence of fructose, produced 53% siderophore units under iron-free minimal MM9 medium and produced 1.8 µmol ml^?1 ammonia in peptone water broth. Plant growth promotion by test isolate was studied on groundnut (Arachis hypogaea L.) under non-saline and saline soil. There was increase by 18% in total plant length and 30% in fresh biomass observed under non-saline control soil. Under saline soil, test isolate showed 17% increase in total length of the plant and 13% increase in fresh biomass.     

Effects of thymol and diphenyliodonium chloride against Campylobacter spp. during pure and mixed culture in vitro

Aims: To determine if the purported deaminase inhibitors diphenyliodonium chloride (DIC) and thymol reduce the growth and survivability of Campylobacter. Methods and Results: Growth rates of Campylobacter jejuni and Camp. coli were reduced compared to unsupplemented controls during culture in Muellar–Hinton broth supplemented with 0·25 μmol DIC or thymol ml^?1 but not with 0·01 μmol monensin ml^?1 or 1% ethanol. Recovery of Camp. jejuni and Camp. coli was reduced >5 log₁₀ CFU from controls after 24 h pure culture in Bolton broth supplemented with 0·25 or 1·0 μmol DIC ml^?1 or with 1·0 μmol thymol ml^?1. Similarly, each test Campylobacter strain was reduced >3 log₁₀ CFU from controls after 24 h mixed culture with porcine faecal microbes in Bolton broth supplemented with 0·25 or 1·0 μmol DIC ml^?1 or with 1·0 μmol thymol ml^?1. Treatments with 0·25 μmol thymol ml^?1, 0·01 μmol monensin ml^?1 or 1% ethanol were less effective. Ammonia production during culture or incubation of cell lysates was reduced by 0·25 or 1·0 μmol DIC ml^?1 but only intermittently reduced, if at all, by the other treatments. Conclusions: Diphenyliodonium chloride and thymol reduced growth, survivability and ammonia production of Camp. jejuni and Camp. coli. Significance and Impact of the Study: Results suggest a potential physiological characteristic that may be exploited to develop interventions.     

Phosphate solubilization and growth promotion by <Emphasis Type="Italic">Pseudomonas fragi</Emphasis> CS11RH1 (MTCC 8984), a psychrotolerant bacterium isolated from a high altitude Himalayan rhizosphere

Phosphate solubilization and growth promotion by Pseudomonas fragi CS11RH1 (MTCC 8984), a psychrotolerant bacterium isolated from a high altitude garlic rhizosphere from the Indian Himalayas, are reported here. The identity of the isolate was arrived on the basis of its biochemical features and sequencing of the 16S rRNA gene. The isolate grew and solubilized phosphate at temperatures ranging from 4 to 30°C. Besides solubilizing P it produced indole acetic acid (IAA) and hydrogen cyanide (HCN). Seed bacterization with the isolate significantly increased the percent germination, rate of germination, plant biomass and nutrient uptake of wheat seedlings. While Pseudomonas fragi is normally associated with the spoilage of dairy products stored at cold temperatures, this is an early report on the plant growth promoting ability of the bacterium.     

Isolation and Characterization of Nonrhizobial Plant Growth Promoting Bacteria from Nodules of <Emphasis Type="Italic">Kudzu</Emphasis> (<Emphasis Type="Italic">Pueraria thunbergiana</Emphasis>) and Their Effect on Wheat Seedling Growth

The leguminous vine Kudzu (Pueraria thunbergiana) is an introduction into the N. W. Himalayan region of India. Despite its value as a fodder and cover crop, little is known about the nature of the nodule microflora. In an attempt to study the nodule bacteria, we isolated and characterized three nonrhizobial plant growth promoting bacteria from surface sterilized nodules of Kudzu. Based on the sequencing of the 16 S r RNA gene, the isolates were designated as Bacillus thuringiensis KR-1, Enterobacter asburiae KR-3, and Serratia marcescens KR-4. Crystalline bodies were detected in the isolate KR-1, confirming its identity as B. thuringiensis. Under in vitro conditions, all three isolates were found to produce indole acetic acid. Other plant growth promotion attributes such as P solubilization, hydrogen cyanide production, and ammonia production varied among the isolates. All of the three isolates promoted growth and positively influenced nutrient uptake parameters of wheat seedlings.     

Temperature × light interaction and tolerance of high water temperature in the planktonic freshwater flagellates Cryptomonas (Cryptophyceae) and Dinobryon (Chrysophyceae)

Using microcosm experiments, we investigated the interactive effects of temperature and light on specific growth rates of three species each of the phytoplanktonic genera Cryptomonas and Dinobryon. Several species of these genera play important roles in the food web of lakes and seem to be sensitive to high water temperature. We measured growth rates at three to four photon flux densities ranging from 10 to 240 μmol photon · m^?2 · s^?1 and at 4–5 temperatures ranging from 10°C to 28°C. The temperature × light interaction was generally strong, species specific, and also genus specific. Five of the six species studied tolerated 25°C when light availability was high; however, low light reduced tolerance of high temperatures. Growth rates of all six species were unaffected by temperature in the 10°C–15°C range at light levels ≤50 μmol photon · m^?2 · s^?1. At high light, growth rates of Cryptomonas spp. increased with temperature until the temperature optimum was reached and then declined. The Dinobryon species were less sensitive than Cryptomonas spp. to photon flux densities of 40 μmol photon · m^?2 · s^?1 and 200 μmol photon · m^?2 · s^?1 over the entire temperature range but did not grow under a combination of very low light (10 μmol photon · m^?2 · s^?1) and high temperature (≥20°C). Among the three Cryptomonas species, cell volume declined with temperature and the maximum temperature tolerated was negatively related to cell size. Since Cryptomonas is important food for microzooplankton, these trends may affect the pelagic carbon flow if lake warming continues.     

Plant growth-promoting activity in newly isolated <Emphasis Type="Italic">Bacillus thioparus</Emphasis> (NII-0902) from Western <Emphasis Type="Italic">ghat</Emphasis> forest,India

A Gram-positive rod-shaped bacterium isolated on nutrient agar plates incubated at 28 ± 2°C. The identity of the bacterium was confirmed by sequencing of the 16S rRNA gene and it reveals that it shares highest similarity with Bacillus thioparus CECT 7196^T (99.08%). It was capable of growing at temperatures ranging from 4 to 40°C, but optimum growth was observed at 28 ± 2°C. Strain NII-0902 is endowed with multiple plant growth promotion attributes such as phosphate solubilization, Indole acetic acid (IAA), siderophore and HCN production, which were expressed differentially at sub-optimal temperatures (5–40°C). It was able to solubilize phosphate (17.7 μg ml⁻¹), and produce IAA (139.7 μg ml⁻¹) at 28 ± 2°C. Qualitative detection of siderophore production and HCN were also observed. At 5°C it was found to express all the plant growth promotion attributes except HCN production. The ability to colonize roots is a sine qua non condition for a rhizobacteria to be considered a true plant growth-promoting rhizobacteria (PGPR). Bacillus sp. NII-0902 has a potential ability to colonize roots visualized by transparency, bacterial growth (turbid, milky and narrow zone) along and around roots and truly supported by scanning electron micrograph. Hence, it is proposed that, Bacillus thioparus sp. NII-0902 could be deployed as an inoculant to attain the desired results of bacterization.     

TEMPERATURE AND IRRADIANCE EFFECTS ON GROWTH OF PITHOPHORA OEDOGONIA (CHLOROPHYCEAE) AND SPIROGYRA SP. (CHAROPHYCEAE)1

Growth responses of Pithophora oedogonia (Mont.) Wittr. and Spirogyra sp. to nine combinations of temperature (15°, 25°, and 35°C) and photon flux rate (50, 100, and 500 μmol·m^?2·s^?1) were determined using a three-factorial design. Maximum growth rates were measured at 35°C and 500 pmol·m^?2·s^?1 for P. oedogonia (0.247 d^?1) and 25°C and 500 μmol·m^?2·s^?1 for Spirogyra sp. (0.224 d^?1). Growth rates of P. oedogonia were strongly inhibited at 15°C (average decrease= 89%of maximum rate), indicating that this species is warm stenothermal. Growth rates of Spirogyra sp. were only moderately inhibited at 15° and 35°C (average decrease = 36 and 30%, respectively), suggesting that this species is eurythermal over the temperature range employed. Photon flux rate had a greater influence on growth of Spirogyra sp. (31% reduction at 50 pmol·m^?2·s^?1 and 25°C) than it did on growth of P. oedogonia (16% reduction at 50 μmol·m^?2·s^?1 and 35°C). Spirogyra sp. also exhibited much greater adjustments to its content of chlorophyll a (0.22–3.34 μg·mg fwt^?1) than did P. oedogonia (1.35–3.08 μg·mg fwt^?1). The chlorophyll a content of Spirogyra sp. increased in response to both reductions in photon flux rate and high temperatures (35°C). Observed species differences are discussed with respect to in situ patterns of seasonal abundance in Surrey Lake, Indiana, the effect of algal mat anatomy on the internal light environment, and the process of acclimation to changes in temperature and irradiance conditions.     

Ventilation and oxygen consumption in the hagfish, Myxine glutinosa L.

Ventilation was measured directly in the hagfish, Myxine glutinosa L., by means of an electro-magnetic blood flowmeter. Ventilatory flow and frequency increased from 0.86 ± 0.27 ml·min^?, and 18.2 ± 5.1·min^?, respectively, at 7°C to 1.70 ± 0.20 ml·min^?, and 70.1 ± 9.5·min^? at 15 ·C.Standard oxygen consumption,V?O₂, was measured in non-buried hagfish. V?O₂ was 0.57 ± 0.17μl O₂·g^?1·min^?1 at 7°C, and 0.85 ± 0.12μl O₂·g^?1·min^?1 at 15°C.     

Kocuria SM1 controls vibriosis in rainbow trout (Oncorhynchus mykiss,Walbaum)

Aims: To develop probiotics for the control of vibriosis caused by Vibrio anguillarum and Vibrio ordalii in finfish. Methods and Results: Kocuria SM1, isolated from the digestive tract of rainbow trout, was administered orally to rainbow trout (Oncorhynchus mykiss) for 2 weeks at a dose equivalent to c. 10⁸ cells per g of feed and then challenged intraperitoneally with V. anguillarum and V. ordalii. Use of SM1 led to a reduction in mortalities to 15–20% compared to 74–80% mortalities in the controls. SM1 stimulated both cellular and humoral immune responses in rainbow trout, by elevation of leucocytes (5·5 ± 0·8 × 10⁶ ml^?1 from 3·7 ± 0·8 × 10⁶ ml^?1), erythrocytes (1·2 ± 0·1 × 10⁸ ml^?1 from 0·8 ± 0·1 × 10⁸ ml^?1), protein (23 ± 4·4 mg ml^?1 from 16 ± 1·3 mg ml^?1), globulin (15·7 ± 0·2 mg ml^?1 from 9·9 ± 0·1 mg ml^?1) and albumin (7·3 ± 0·2 mg ml^?1 from 6·1 ± 0·1 mg ml^?1) levels, upregulation of respiratory burst (0·05 ± 0·01 from 0·02 ± 0·01), complement (56 ± 7·2 units ml^?1 from 40 ± 8·0 units ml^?1), lysozyme (920 ± 128·8 units ml^?1 from 760 ± 115·3 units ml^?1) and bacterial killing activities. Conclusions: Kocuria SM1 successfully controlled vibriosis in rainbow trout, and the mode of action reflected stimulation of the host innate immune system. Significance and Impact of the Study: Probiotics can contribute a significant role in fish disease control strategies, and their use may replace some of the inhibitory chemicals currently used in fish farms.