• Asian-Australasian Journal of Animal Sciences
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• v.30 no.4
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• pp.593-601
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• 2017

Objective: The aim of this study was to evaluate heat tolerance using heat tolerance indices, physiological, physical, thermographic, and hematological parameters in Santa Ines and Morada Nova sheep breeds in the Federal District, Brazil. Methods: Twenty-six adult hair sheep, one and a half years old, from two genetic groups (Santa Ines: 12 males and 4 females; Morada Nova: 7 males and 3 females) were used and data (rectal temperature, respiratory rate, heart rate, skin temperatures; hematological parameters) were collected during three consecutive days, twice a day (morning and afternoon), with a total of six repetitions. Also physical parameters (biometric measurements, skin and hair traits) and heat tolerance indices (temperature-humidity index, Iberia and Benezra) were evaluated. The analyses included analyses of variance, correlation, and principal components with a significance level of 5%. Results: The environmental indices, in general, indicate a situation of thermal discomfort for the animals during the afternoon. Breed significantly influenced (p<0.001) physiological and physical characteristics of skin, hair, biometric measurements and Iberia and Benezra heat tolerance indices. Santa Ines animals were bigger and had longer, greater number and darker hair, thicker skin, greater respiratory rate and Benezra index and lower Iberia index compared with Morada Nova breed. Conclusion: Although both breeds can be considered adapted to the environmental conditions of the region, Morada Nova breed is most suitable for farming in the Midwest region. The positive correlation found between the thermographic temperatures and physiological parameters indicates that this technique can be used to evaluate thermal comfort. Also, it has the advantage that animals do not have to be handled, which favors animal welfare.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.63 no.4
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• pp.314-321
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• 2018

Durum (Triticum turgidum L. ssp. durum) is a major crop species cultivated for human consumption worldwide. In Tunisia, salt stress is one of the main problems that limit crop production. 'Mahmoudi' was selected as the most salt-sensitive out of 11 Tunisian durum cultivars. Using the salt-tolerant cultivar 'Om Rabia', resistant and susceptible cultivars were evaluated to compare genetic responses under salt stress. At the fully expanded third leaf stage, salt stress was applied by submerging the pots in 500 mM NaCl for 5 min every day for saline water irrigation in the greenhouse. The treatment was applied for 1 week and salt stress tolerance was determined by changes of growth parameters to the control condition. The salt tolerance trait index and salt tolerance index were calculated and used as selection criteria. The expression levels of TdHKT1;4, TdHKT1;5, and TdSOS1 were examined using qPCR. For further evaluation of physiological responses, salt stress (150 mM NaCl) was additionally applied for 48 h at the fully expanded third-leaf stage. Increased expression of the genes responsible for salt tolerance and proline content in tolerant durum can be used to broaden genetic diversity and provide genetic resources for the durum breeding program.

• Korean Journal of Microbiology
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• v.30 no.6
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• pp.444-449
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• 1992

A total of 858 heterotrohic bacteria were isolated and analyzed hy numerical method to investigate the heterotrophic hacterial community structure in Naktong Estuary. Although the values of H' (Shannon's diversity index). ranged between 1.54 and 3.49. were similar with those of the data hefore the construction of Naktong River barrage, however J' (evenness index. 0.31-0.80) was reduced. Physiological tolerance index for water temperature ($P_{s}$) was high at St.l and 2 whose depthes arc shallower than the other stations. and indices for pH ($P_{h}$) and salinity ($P_{s}$) were high at St. 2. 3. 4 where freshwater and seawater arc mixed. The predominant clusters were identified as Aeromonas. Vihrio. Pseudomonas. Acinelobacter-Morexella. Alcaligenes. Flavobacterium. Micrococcaccae. and Enterohacteriaceae. The kinds nf the isolates were similar with the previous result. hut the dominant genus was changed. These results suggest that the environmental changes in Naktong Estuary affect the hacterial physiological adaptation rather than the composition of heterotrophic hactcrial community.

• Korean Journal of Microbiology
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• v.25 no.3
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• pp.229-237
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• 1987

To determine the characteristics of heterotrophic bacterial community in estuarine ecosystem, water and sediment samples were taden from Naktong estuary. All isolates were compared with 73 characters and described by cluster analysis. With same characters, 30 reference strains were able to divide into approximate species level at 80% similarity (S value). Diversity indices ($H^{1}$) of sediment column isolates were higher than water column isolates. The bacterial community commonly appeared in water and sediment column was reduced with going to downstream. Tolerance indices for temperature (Pt) and salinity (Ps) were also higher in sediment isolates than in water isolates. The bacterial community in sediment column is believed to be composed with diverse populations compared to water column and maintains its stability against various environmental changes with high physiological tolerances.

• Korean Journal of Agricultural and Forest Meteorology
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• v.11 no.1
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• pp.3-12
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• 2009

Ozone tolerance of tree species was determined by standard index of physiological damages and biochemical defense responses under short-term ozone exposure. At the end of 150ppb $O_3$ fumigation, photosynthetic characteristics and antioxidative enzyme activities were analyzed in the leaves of five species(Koelreuteria paniculata, Firmiana simplex, Styrax japonica, Fraxinus rhynchophylla, Viburnum sargentii). Injury index was determined by the effect of ozone on photosynthetic parameters and malondialdehyde(MDA) content, and tolerance index was calculated using the rate of increase in superoxide dismutase(SOD), ascorbate-peroxidase(APX), glutathione reductase(GR) and catalase(CAT) activities. Apparent quantum yield(AQY), carboxylation efficiency(Ce) and photo-respiration rate(PR) decreased in the leaves of five species with increasing ozone exposure time. These parameters were considered as an appropriate indicator for stress evaluation. Antioxidative enzyme activities showed various results depending on the tree species, exposure time, and enzyme types. SOD activity of K. paniculata increased with ozone exposure time, and that of F. rhynchophylla increased only after 6 hours of ozone exposure. CAT activity of $O_3$-exposed F. simplex was lower than the control. Based on standard index, ozone tolerance ability of five species was determined as two tolerant species(F. rhynchophylla > K. paniculata) and three sensitive species(S. japonica > F. simplex > V. sargentii).

• KOREAN JOURNAL OF CROP SCIENCE
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• v.36 no.5
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• pp.429-444
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• 1991

Cold stress influence plant growth through a wide range of growth characters. Adverse effects of low temperature to plant growth come from results of colligative and complex physiological responses to cold stress. To evaluate more exactly cold tolerance of crop plant, it is needed to observe physiological changes induced by cold stress and to analyze relationships between intraspecific variations in physiological factors related to cold tolerance and the extent of cold tolerance in the field. Therefore, the composition and unsaturation ratio of fatty acids in phospholipid, a constituent of membrane, the transition-temperature in respiratory activity of mitochodria, the chlorophyll fluorescence as a factor related to photosynthesis were investigated in rice plant and data on these factors were compared with the degree of cold tolerance obtained in the field experiment. Also, effects of hardening and Mn++ treatment were evaluated as a method to reduce chilling injuries. The unsaturation ratio of fatty acids, whether rice plants were grown in a natural condition or under the chilling stress, was higher in the cold- tolerant varieties and was significantly correlated with the degree of cold tolerance (1-9) observed in the field experiment. And it was also increased by chilling treatment or hardening treatment, due to a reduction in palmitic acid content and an increase in linolenic acid content. The transition-temperature of respiratory activity of mitochodria isolated from etiolated rice seedlings ($25^{\circ}C$, two week-grown in the dark), was correlated with the degree of cold tolerance in the field, cold -tolerant varieties showing a lower transition-temperature. It was not influenced by growth stages. The intensity of chlorophyll fluorescence was highly correlated with the degree of cold tolerance, cold-tolerant varieties having a higher fluorescence intensity. By foliar application of Mn, the transition-temperature of respiratory activity was lowered as much as 0-2$^{\circ}C$ in all tested varieties. Soil application of Mn induced more significant effect in cold-susceptible varieties with a possibility of reducing chilling injuries. On the whole, there were high correlationships among the degree of cold tolerance, the unsaturation ratio of fatty acids in phospholipid, the transition- temperature of respiratory activity and chlorophyll fluorescence except for a few varieties. The transition- temperature of respiratory activity appeared to be negatively correlated with the unsaturation ratio of fatty acids. and the chlorophyll fluorescence to be positively correlated with the unsaturation ratio. This implies that these physical and physiological factors were very closely related to cold tolerance and can be used as an effective index of the evaluation of cold tolerance of crop plant. But other factors as well as three factors discussed above are needed to be considered colligatively and altogether with a systematic analysis for the more exact evaluation of cold tolerance. in rice cultivars. in rice cultivars.

• Journal of Microbiology and Biotechnology
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• v.31 no.1
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• pp.92-103
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• 2021

Lactobacillus casei, one of the most widely used probiotics, has been reported to alleviate multiple diseases. However, the effects of this species on intestinal diseases are strain-specific. Here, we aimed to screen L. casei strains with inflammatory bowel disease (IBD)-alleviating effects based on in vitro physiological characteristics. Therefore, the physiological characteristics of 29 L. casei strains were determined, including gastrointestinal transit tolerance, oligosaccharide fermentation, HT-29 cell adhesion, generation time, exopolysaccharide production, acetic acid production, and conjugated linoleic acid synthesis. The effects of five candidate strains on mice with induced colitis were also evaluated. The results showed that among all tested L. casei strains, only Lactobacillus casei M2S01 effectively relieved colitis. This strain recovered body weight, restored disease activity index score, and promoted anti-inflammatory cytokine expression. Gut microbiota sequencing showed that L. casei M2S01 restored a healthy gut microbiome composition. The western blotting showed that the alleviating effects of L. casei M2S01 on IBD were related to the inhibition of the NF-κB pathway. A good gastrointestinal tolerance ability may be one of the prerequisites for the IBD-alleviating effects of L. casei. Our results verified the efficacy of L. casei in alleviating IBD and lay the foundation for the rapid screening of L. casei strain with IBD-alleviating effects.

• Korean Journal of Microbiology
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• v.26 no.3
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• pp.256-261
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• 1988

Samples from Naktong Estuary had been taken for the characterization of heterotrophic bacterial communities and of the effects of environmental factors on their distribution in estuarine ecosystem. Bacterial communities isolated from seawater region were composed of more euryhalone groups than those from freshwater region, and the bacterial communities of summer were composed of more eurythermal groups than those of winter. Bacterial commnities became more diverse by the input of allochthonous bacteria from terrestrial and freshwater ecosystem, but less diverse by worse environmental conditions such as nutrient load, high salinity, low temperature, and so on.

• Korean Journal of Environmental Biology
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• v.40 no.3
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• pp.247-254
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• 2022

To investigate the tolerance limit and critical thermal maximum (CTM), behavioral responses of wild goldeye rockfish Sebastes thompsoni according to exposure to high water temperature were observed using a continuous behavior tracking system. As a result, behavioral index (BI) of S. thompsoni in each temperature (20.0, 25.0, and 30.0℃) showed a significant difference (p<0.05) when compared with the value measured in a stable condition of 15.0℃. The activity level of S. thompsoni exposed to 25.0℃ decreased sharply after 20 hours. Their rest time at the bottom of experiment chamber increased, and their normal swimming and metabolic activities were disturbed. In addition, at a high water temperature of 30.0℃, S. thompsoni reached the limit of resistance and showed a sub-lethal reaction of swimming behavior, with energy consumption in the body increased and all test organisms died. In conclusion, the eco-physiological response of S. thompsoni to water temperature varied greatly depending on the fluctuation range of the exposed temperature and the exposure time. In addition, the tolerance limit of S. thompsoni to high water temperature was predicted to be 25.0-30.0℃. The maximum critical thermal that had a great influence on the survival of this species was found to be around 30.0℃.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.48 no.6
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• pp.516-526
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• 2003

Thirty-six barley varieties including Korean modern and local varieties were tested for drought-tolerance in the field of plastic rain shelter, Drought treatment was initiated at initial tillering stage (March 27, 2002) by withholding irrigation and lasted until harvest. Soil water potential maintained at around -0.05㎫ in the control plot and varied from -0.05㎫ (at the initial stage of drought treatment) to -0.29㎫ in the drought treatment plot. At forty days after drought treatment, relative water content (RWC), osmotic potential (OP), osmotic adjustment (OA), and $^{13}\textrm{C}$ discrimination ($\Delta$) were measured and then plants were sampled for leaf area index (LAI) and dry weight (DW). Barley was harvested at maturity for determining DW, grain yield, 1000 grains weight and number of spikelet. The tested varieties revealed wide spectrum of drought tolerance. Dongbori-1, Chalbori, Changyeongjaerae, Samdobori and Weolseong 87-31 showed strong drought-tolerance while Songhagbori and Suwonmaeg360 showed weak drought-tolerance. The drought injury indexes (drought/control ratio) of DW and yield revealed significant positive correlation with leaf RWC in drought treatment plot and $\Delta$ in the control plot, but obvious negative correlation with leaf OP and OA under drought condition. In addition, all the drought indexes of OP, $\Delta$ and RWC showed obvious positive correlation with the drought injury indexes of DW, 1000 grain weight and yield. Thus, OP and RWC under drought condition and $\Delta$ under well-watered condition would be used as the evaluation criteria for drought- tolerance of barley genotypes. However, further investigation is needed for the relationship between $\Delta$ and drought-tolerance as the other reports were not consistent with our result.