Postharvest litchi (Litchi chinensis Sonn.) quality preservation by Lactobacillus plantarum

The objective of this work was to preserve the postharvest quality of litchi cv Brewster by the application of Lactobacillus plantarum. A suspension of 1 × 10⁹ CFU/mL of the bacteria was sprayed on ripe litchis and then stored at 10 °C with 75% of relative humidity. Treated fruit exhibited a significantly higher Gram positive bacteria growth on the rind (4–5 log CFU/g) than that detected in control fruit (2.5–3.75 log CFU/g). This result was corroborated by observing a high population of lactobacilli in scanning electron micrographs and by measurement of the content of lactic acid produced. Treated fruit displayed significantly (α ≤ 0.05) reduced color losses as indicated by the higher L* and C* values in comparison with the untreated ones. Additionally, cyanidin-3-rutinoside and total anthocyanin contents supported the measured color retention, since the pericarp of fruit treated with Lb. plantarum showed a significantly higher concentration of pigments than those used as control. In addition, a high concentration of phenolic compounds was found in the rind of treated fruit.     

Multi-locus sequence analysis reveals host specific association between Bartonella washoensis and squirrels

To clarify phylogenetic relationships and genetic diversity among Bartonella washoensis strains obtained from squirrels, multi-locus sequence analysis (MLSA) with the 16S rRNA, ftsZ, gltA, groEL, ribC, and rpoB genes was applied for 20 strains of B. washoensis isolated from five genera of squirrels (Tamias, Tamiasciurus, Glaucomys, Sciurus, and Spermophilus) within the family Sciuridae. Sequence similarities in the concatenated sequences of B. washoensis strains from squirrels of different genera ranged from 94.7% (Sciurus vs. Spermophilus) to 98.4% (Tamiasciurus vs. Glaucomys). Phylogenetic trees based on the concatenated sequences revealed that B. washoensis strains formed five distinct clades and each clade correlated with the genus of squirrel from which the strains were originally obtained. The discrimination was supported by 100% bootstrap values and posterior probabilities, respectively. These results suggest that B. washoensis strains may have co-speciated with their squirrel hosts and provide new insights into the application of the MLSA to identify sources of B. washoensis infection with accuracy.     

Effect of the temperature-humidity index on body temperature and conception rate of lactating dairy cows in southwestern Japan

In the present study, we investigated the relationship between the temperature-humidity index (THI) and the conception rate of lactating dairy cows in southwestern Japan, one of the hottest areas of the country. We also investigated the relationship between measurement of the vaginal temperature of lactating dairy cows as their core body temperature at one-hour intervals for 25 consecutive days in hot (August-September, n=6) and cool (January-February, n=5) periods and their THI. Furthermore, we discussed the above relationship using these vaginal temperatures, the conception rates and the THI. As a result, when the conception rates from day 2 to 0 before AI were classified into day 2, 1 and 0 groups by the six maximum THI values in each group (mTHI; <61, 61-65, 66-70, 71-75, 76-80, >80), only the conception rate for the mTHI over 80 at 1 day before AI group was significantly lower (P<0.05) than the other groups. The conception rate for days 15 to 17, but not days 19 to 22 and 30 to 35, after AI in the cows that experienced average mTHI over 80 (amTHI>80) was significantly lower (P<0.05) than that of the cows that did not experience amTHI>80. There was a significant positive correlation (P<0.01) between the mTHI and the mean daily vaginal temperature, but not during the cool period. When the mTHI reached 69, the vaginal temperature started to increase. As for the relationship between the conception rates and vaginal temperatures for all mTHI classes, in the mTHI>80 at 1 day before AI group, the vaginal temperature increased by 0.6 C from 38.7 C, resulting in a reduction of 11.6% in the conception rate from 40.5%. In conclusion, these results suggest that one of the causes of the fall in conception rate of lactating dairy cows during the summer season in southwestern Japan may be an increase in their core body temperature with a higher mTHI than the critical mTHI of 69 at 1 day before AI.     

Staphylococcus pseudintermedius exfoliative toxin EXI selectively digests canine desmoglein 1 and causes subcorneal clefts in canine epidermis

Staphylococcal exfoliative toxins are known to digest desmoglein (Dsg) 1, a desmosomal cell–cell adhesion molecule, thus causing intraepidermal splitting in human bullous impetigo, staphylococcal scalded skin syndrome and swine exudative epidermitis. Recently, a novel exfoliative toxin gene (exi), whose sequence shares significant homology with previously identified exfoliative toxins, was isolated from Staphylococcus pseudintermedius. Little is known about the pathogenic involvement of this toxin in canine pustular diseases such as impetigo. The aim of this study was to determine whether EXI, the product of the exi gene, digests canine Dsg1 and causes intraepidermal splitting in canine skin. An exi gene was isolated from chromosomal DNA of an S. pseudintermedius strain obtained from a pustule of a dog with impetigo, and was used to produce a recombinant EXI by Escherichia coli expression. When purified recombinant EXI was injected intradermally into normal dogs, it caused the development of vesicles or erosions with superficial epidermal splitting. In addition, the EXI abolished immunofluorescence for Dsg1, but not for Dsg3, at the injection sites. Moreover, the EXI directly degraded baculovirus‐secreted recombinant extracellular domains of canine Dsg1, but not that of canine Dsg3, in vitro. The EXI also degraded mouse Dsg1α and swine Dsg1, but not human Dsg1, mouse Dsg1β and Dsg1γ. Conversely, recombinant SIET, previously designated as S. intermedius exfoliative toxin, did not cause intraepidermal splitting or degradation of any Dsgs. These findings indicate that EXI has a proteolytic activity that digests canine Dsg1, and this characteristic might be involved in the pathogenesis of intraepidermal splitting in canine impetigo.     

Hepatic gene expression of the insulin signaling pathway is altered by administration of persimmon peel extract: a DNA microarray study using type 2 diabetic Goto-Kakizaki rats

Persimmon (Diospyros kaki) is a very popular fruit in East Asian countries, but its peels are not consumed despite the fact that they contain many antioxidants such as carotenoids and polyphenols. We prepared a fat-soluble extract from persimmon peel (PP) and fed type 2 diabetic Goto-Kakizaki (GK) rats an AIN-93G rodent diet supplemented with persimmon peel extract (PP diet) for 12 weeks. Compared with the control AIN-93G diet, the PP diet significantly reduced plasma glutamic-pyruvate transaminase activity, with accumulation of β-cryptoxanthin in the liver. DNA microarray analysis revealed that the PP diet altered hepatic gene expression profiles. In particular, expression of insulin signaling pathway-related genes was significantly enriched in differentially expressed gene sets. Moreover, Western blotting analysis showed an increase in insulin receptor beta tyrosine phosphorylation in rats fed the PP diet. These data suggest that the PP diet improves insulin resistance in GK rats.     

Measurement of the fate of acetic acid form carbon in soil solution of flooded soils using high performance liquid chromatography coupled with isotope ratio mass spectrometry

Carbon-14 (¹⁴C) which can be taken into low molecular weight organic compounds (e.g. acetic acid, formic acid, methanol and ethanol) is one of the most important radionuclides released from transuranic waste disposal sites. To understand the fate of organic compounds in the soil environment, a stable carbon isotope, ¹³C, can be used as a tracer of ¹⁴C. In this study, ¹³C-labeled acetic acid was added to six soil-water mixture samples and the chemical form changes in the soil solutions were measured by high performance liquid chromatography coupled with isotope ratio mass spectrometry. The ¹³C-labeled acetic acid in the soil solutions was detected for the first 24 h, but could not be detected afterwards for any soil samples. Thus, in any soils that have similar properties to the soil samples used in the present study, most of the ¹³C-labeled acetic acid would likely be changed to other physico-chemical forms and be removed from the soil solutions in a very short time period. Less than 3% of the carbon added as acetic acid remained in the soil solutions, and was possibly mainly in inorganic forms. Carbon from acetic acid would not be retained in soil solutions for 48 h.     

Improved uptake models of nonionized pesticides to foliage and seed of crops.

The residual amount of nonionized pesticides incorporated to foliage and stem (foliage) and seed (fruit) of crops via root hairs from the water phase was estimated using the uptake models newly including metabolic parameters by which the amount of intact pesticide remaining in crops was considered with its proportion in a transpiration stream. A new parameter was also introduced for the seed model that accounts for the pesticide loss by adsorption to the inner surface of xylem tissue. Validation of the model was conducted using six pesticides with soybean and spinach plants. The ratio of the predicted concentration of pesticide to the measured one was 0.44-1.49 and 0.57-2.93 with foliage and seed models, respectively, showing that these improved models would be effective as a prediction tool.     

Effect of Platelet-Rich Plasma-Incorporated Gelatin Hydrogel Microspheres and Subchondral Drilling on Equine Cartilage Defects

We evaluated the effect of platelet-rich plasma-incorporated gelatin hydrogel microsphere (PRP/GM) together with subchondral drilling for cartilage regeneration in horses. Cartilage defects (diameter, 4.5 mm; depth, 3.0 mm) were created in both third carpal bones of six Thoroughbred horses. A subchondral hole was drilled at the center of this cartilage defect (diameter, 2.0 mm; depth, 35 mm) in one randomly selected carpal joint (test joint), whereas no subchondral hole was made in the contralateral joint (control joint). Thereafter, the test joint was injected with PRP/GM and the control joint with saline-infused GM. Additional injections of PRP/GM were given 14 and 28 days after surgery. After 16 weeks, histologic analysis was conducted. The macroscopic and histologic scores of the test group were significantly higher than those of the control group (P < .05). These data indicated that the application of PRP/GM together with subchondral drilling accelerated cartilage regeneration in horses.     

A survey of Blastocystis infection in anuran and urodele amphibians

Blastocystis infection in amphibians was surveyed in three species of anuran and one species of urodele amphibians captured at two distinct locations in Japan. All three species of frogs were highly infected with Blastocystis, while 69 individual urodele newts, Cynopus pyrrhogaster, were negative for infection. Eleven Blastocystis isolates (47.8%) were recovered from 23 Rana nigromaculata leopard frogs. Twenty-three (92%) of 25 Rana catesbeiana bullfrogs and all (100%) of 24 Bufo japonicus japonicus toads were positive for Blastocystis. Two distinct populations of the toad and bullfrog showed a high prevalence (100 or 84.6%) of Blastocystis infection, while in two populations of the leopard frog only one population was positive for Blastocystis (84.6%). Three Blastocystis isolates from different species of the frogs were established. Since none of the three isolates could survive at 37 degrees C, a temperature tolerance assay was performed to assess the optimal growth temperature and to determine the range of non-lethal temperatures. During the exponential growth phase of 3- or 4-day cultures at 25 degrees C, three isolates were exposed to 4, 28, 31, or 34 degrees C for 3 days and then returned to 25 degrees C to monitor the cell growth. Based on the optimal growth temperatures and different ranges of temperature tolerance among the three new isolates from frogs and two known species, Blastocystis hominis and Blastocystis lapemi, it was established that the three isolates recovered from different species of frogs had different physiological features from B. hominis and B. lapemi.