Elevation of liver-galactosylhydroxylysyl glucosyltransferase activity in human primary hepatocellular carcinoma

The activity of L-GGT (EC 2.4.1.66), an enzyme catalyzing the intracellular biosynthesis of collagen, was determined in human primary hepatic cancer, acute viral hepatitis and cirrhotic liver tissues and compared to the mean level of enzyme activity in normal human liver tissues. The mean levels of L-GGT activity in primary hepatocellular carcinoma (PHC), acute viral hepatitis and cirrhotic tissues were 7.78, 2.69 and 2.16 times the mean level of enzyme activity in normal human liver tissues. The mean level of L-GGT activity in PHC was 3.61 times the mean level of L-GGT activity in cirrhosis and 2.90 times the mean value of liver enzyme activity in acute viral hepatitis. The findings in this study provide a basis for the highly elevated serum values of this intracellular enzyme in patients with primary hepatic cancer and the data indicate that L-GGT activity may be increased in primary liver cancer to compensate for an increased rate of collagen synthesis.     

The HAL1 function on Na+ homeostasis is maintained over time in salt-treated transgenic tomato plants, but the high reduction of Na+ in leaf is not associated with salt tolerance

To achieve a deeper knowledge on the function of HAL1 gene in tomato ( Solanum lycopersicum ) plants submitted to salt stress, in this study, we studied the growth and physiological responses to high salt stress of T3 transgenic plants (an azygous line without transgene and both homozygous and hemizygous lines for HAL1 ) proceeding from a primary transformant with a very high expression level of HAL1 gene. The homozygous plants for HAL1 gene did not increase their salt tolerance in spite of an earlier and higher reduction of the Na⁺ accumulation in leaves, being moreover the Na⁺ homeostasis maintained throughout the growth cycle. The greater ability of the homozygous line to regulate the Na⁺ transport to the shoot to long term was even shown in low accumulation of Na⁺ in fruits. By comparing the homozygous and hemizygous lines, a higher salt tolerance in the hemizygous line, with respect to the homozygous line, was observed on the basis of fruit yield. The Na⁺ homeostasis and osmotic homeostasis were also different in homozygous and hemizygous lines. Indeed, the Na⁺ accumulation rate in leaves was greater in hemizygous than in homozygous line after 35 days of 100 m M NaCl treatment and only at the end of growth cycle did the hemizygous line show leaf Na⁺ levels similar to those found in the homozygous line. With respect to the osmotic homeostasis, the main difference between lines was the different contribution of inorganic and organic solutes to the leaf osmotic balance. Taken together, these results suggest that the greater Na⁺ exclusion ability of the homozygous line overexpressing HAL1 induces a greater use of organic solutes for osmotic balance, which seems to have an energy cost and hence a growth penalty that reverts negatively on fruit yield.     

Validation of trans-rectal ultrasonography for counting preovulatory follicles in weaned sows

The present study investigated the accuracy of trans-rectal ultrasonography (TRU) for assessing the exact number of preovulatory follicles (POFs, with a diameter from 6 to 10mm) present in the ovaries of weaned sows. The ovaries of 63 hormonally treated (1500 IU of eCG) weaned sows were checked with TRU (7.5-MHz multiple scan angle transducer) in two successive scanning sessions performed at 26-27 and 30-31h after the beginning of oestrus signs, and the maximum number of POFs were counted. Sows were subjected to laparoscopy (LAP) immediately after the last TRU scan to confirm the number of POFs. The differences (mean+/-S.D.) in the number of POFs counted with TRU and LAP on each ovary were analyzed as a whole and after sorting the ovaries into three classes according to the number of POFs visualized by LAP: (1) less than 7; (2) from 7 to 13; and (3) more than 13. A significant correlation (P<0.01) was found between TRU and LAP for both the whole data set (126 ovaries) and in each of the three ovarian classes. Despite the significant correlation, TRU underestimated the number of POFs by 1.40+/-1.67 compared with LAP (P<0.001). However, the underestimation varied among the ovarian classes. This difference was not significant (P>0.05) in class 1 and was significant (P<0.001) in classes 2 (1.11+/-1.30 less POFs than counted by TRU) and 3 (3.19+/-1.54 less POFs than counted by TRU). In conclusion, TRU is a valuable tool to count the number of POFs present in the ovaries of weaned sows, but a certain degree of underestimation should be expected when the number of POFs is large.     

Osmotic adjustment in leaves ofLycopersicon esculentum andL. pennellii in response to saline water irrigation

Two tomato species (Lycopersicon esculentum andL. pennellii) were grown under unheated plastic greenhouse and irrigated with 0 or 140 mM NaCl. Salinity induces a more important reduction in predawn leaf water potential (ψ_pd) inL. esculentum than inL. pennellii. In both species the osmotic adjustment was achieved by active solute accumulation. The leaf water potential at turgor loss point (ψ_tlp) seemed to be controlled by leaf osmotic potential (ψ_os). The results revealed the existence of limits to the accumulation of osmotic solutes in leaf tissues and the existence of an ontogenetic effect on the solute accumulation. In both species, but essentially inL. pennellii the inorganic solutes contribution especially Na⁺ and Cl^? accumulation to ψ_os was higher than the organic solutes. Therefore, wild species save energy more markedly.     

Grafting raises the salt tolerance of tomato through limiting the transport of sodium and chloride to the shoot

With the aim of determining whether grafting could improve salinity tolerance of tomato (Lycopersicon esculentum Mill.), and what characteristics of the rootstock were required to increase the salt tolerance of the shoot, a commercial tomato hybrid (cv. Jaguar) was grafted onto the roots of several tomato genotypes with different potentials to exclude saline ions. The rootstock effect was assessed by growing plants at different NaCl concentrations (0, 25, 50, and 75 mM NaCl) under greenhouse conditions, and by determining the fruit yield and the leaf physiological changes induced by the rootstock after 60 d and 90 d of salt treatment. The grafting process itself did not affect the fruit yield, as non-grafted plants of cv. Jaguar and those grafted onto their own root showed the same yield over time under non-saline conditions. However, grafting raised fruit yield in Jaguar on most rootstocks, although the positive effect induced by the rootstock was lower at 25 mM NaCl than at 50 and 75 mM NaCl. At these higher levels, the plants grafted onto Radja, Pera and the hybrid VolgogradskijxPera increased their yields by approximately 80%, with respect to the Jaguar plants. The tolerance induced by the rootstock in the shoot was related to ionic rather than osmotic stress caused by salinity, as the differential fruit yield responses among graft combinations were mainly related to the different abilities of rootstocks to regulate the transport of saline ions. This was corroborated by the high negative correlation found between fruit yield and the leaf Na(+) or Cl(-) concentrations in salt-treated plants after 90 d of salt treatment. In conclusion, grafting provides an alternative way to enhance salt tolerance, determined as fruit yield, in the tomato, and evidence is reported that the rootstock is able to reduce ionic stress.     

An insertional mutagenesis programme with an enhancer trap for the identification and tagging of genes involved in abiotic stress tolerance in the tomato wild-related species Solanum pennellii

Salinity and drought have a huge impact on agriculture since there are few areas free of these abiotic stresses and the problem continues to increase. In tomato, the most important horticultural crop worldwide, there are accessions of wild-related species with a high degree of tolerance to salinity and drought. Thus, the finding of insertional mutants with other tolerance levels could lead to the identification and tagging of key genes responsible for abiotic stress tolerance. To this end, we are performing an insertional mutagenesis programme with an enhancer trap in the tomato wild-related species Solanum pennellii. First, we developed an efficient transformation method which has allowed us to generate more than 2,000 T-DNA lines. Next, the collection of S. pennelli T(0) lines has been screened in saline or drought conditions and several presumptive mutants have been selected for their salt and drought sensitivity. Moreover, T-DNA lines with expression of the reporter uidA gene in specific organs, such as vascular bundles, trichomes and stomata, which may play key roles in processes related to abiotic stress tolerance, have been identified. Finally, the growth of T-DNA lines in control conditions allowed us the identification of different development mutants. Taking into account that progenies from the lines are being obtained and that the collection of T-DNA lines is going to enlarge progressively due to the high transformation efficiency achieved, there are great possibilities for identifying key genes involved in different tolerance mechanisms to salinity and drought.     

Relationship between tomato fruit growth and fruit osmotic potential under salinity

To investigate the relationship between fruit growth and fruit osmotic potential (Ψ_s) in salty conditions, a sensitive tomato cultivar (Lycopersicon esculentum Mill.) and a tolerant accession of the wild species Lycopersicon pimpinellifolium Mill. were grown in a greenhouse with 0 and 70 mM NaCl, and the growth of the fruit studied from 15 to 70 days after anthesis (DAA). L. pimpinellifolium did not reduce significantly fruit weight in salty conditions throughout the growth period, whereas L. esculentum fruit weights decreased significantly with salinity from 45 DAA. L. esculentum fruit fresh weight reductions resulted from both less dry matter and water accumulation, although the fruit water content was affected by salinity before the fruit weight. In both species, fruit osmotic potential (Ψ_s) decreased significantly with salinity during the rapid fruit growth phase, although the changes were different. Thus, fruits from L. pimpinellifolium salt treated plants showed a Ψ_s reduction at the beginning (15 DAA) twice as high as that found in L. esculentum. As the advanced growth stage (from 15 to 55 DAA), the Ψ_s reduction percentages induced by salinity were quite similar in L. pimpinellifolium fruits, while increased in L. esculentum. Under saline conditions, the solutes contributing to reduce the fruit Ψ_s during the first 55 DAA were the inorganic solutes in both species, while in the ripe fruits they were hexoses. L. esculentum fruits accumulated K⁺ as the main osmoticum in salty conditions, while L. pimpinellifolium fruits were able to use not only K⁺ but also the Na⁺ provided by the salt.