Participation of Phosphatidylinositol-3 Kinase Signalling in Human Chorionic Gonadotropin, Bovine Insulin (B-Insulin) and Human-Insulin-Like Growth Factor-I Induced Oocyte Maturation and Steroidogenesis in the Grey Mullet, Mugil Cephalus.

CONTEXT: The grey mullet, Mugil cephalus, is an edible fish of high economic importance. Breeding biology with reference to hormonal/growth factor regulation of oocyte maturation needs to be known for its commercial production. OBJECTIVE: The present study was conducted to examine the potency of maturation inducing hormones, chorionic gonadotropin (hCG), bovine-insulin, and insulin like growth factor1 (h-IGF-1) I on ovarian steroidogenesis and oocyte maturation. DESIGN: The role of hormones and growth factors on steroidogenesis and oocyte maturation was investigated using specific inhibitors, Wortmannin for phosphatidylinositol-3 (PI3) kinase, trilostane for 3ß-hydroxysteroid dehydrogenase, 1-octanol and 1-heptanol for gap junctions, actinomycin D for transcription and cycloheximide for translation of signal molecules. METHODS: Actions of hormonal and growth factors were examined for steroidogenesis, by radioimmunoassay and oocyte maturation by germinal vesicle breakdown (GVBD). Specific inhibitors were used to determine the cell signaling pathways, PI3 kinase. RESULTS: All the inhibitors attenuated the hCG-induced oocyte maturation (GVBD%), steroidogenesis including transcription, translation, gap junctions and PI3 kinase signaling. These inhibitors failed to inhibit h-IGF-I and b-insulin-induced oocyte maturation, steroidogenesis, translation and PI3 kinase signaling. CONCLUSION: hCG induces oocyte maturation via steroid dependent pathway involving gap junctions, transcription, translation and PI3 kinase signaling, unlike h-IGF-I and b-insulin in the mullet.

Effect of summer pruning and CPPU on yield and quality of kiwi fruit (Actinidia deliciosa).

A field experiment was conducted on bearing vines of kiwifruit cv. Abbott to find the effect of CPPU (N-(2- chloro-4-pyridyl)-N-phenylurea) and summer pruning on fruit yield, fruit size and quality. CPPU greatly stimulated fruit growth indicating that it can be a powerful tool for improving kiwifruit cropping. Application of CPPU at 10 ppm concentration was done by dipping the fruits for 10 sec in the aqueous solution of compound at petal fall and 30 days after petal fall. CPPU applied fruits increased size by 20-70 g over control. Summer pruning along with CPPU application proved to be more effective in obtaining fruits of high grades with increased fruit weight (95.37 g fruit(-1)) and high quality. Summer pruning, when done by pinching 1/5th at Petal Fall stage + CPPU dipping (10 ml(-1)) and pinching 1/5th continued till harvest, at one month interval resulted in increased fruit yield (54.80 kg vine(-1)), high TSS (17.60 Brix), high total sugar (9.85%), advanced ripening by one week and reduced flesh firmness.

Molecular Detection of Latent Apple chlorotic leaf spot virus in Elite Mother Plants of Apple.

Apple chlorotic leaf spot virus (ACLSV; family Betaflexiviridae genus Trichovirus) is one of the economically important latent virus infecting apple (Malus × domestica Borkh.). Reverse transcriptase polymerase chain reaction (RT-PCR) procedures were used to amplify coat protein gene of ACLSV. Among 5 primer sets used, two primer sets (1F1R and 1F2R) amplified fragments of expected size (432 bp). Products visible on agarose gel were produced using templates extracted from apple leaves. The results were further validated by sequencing fragment of 432 bp which was amplified from leaf of apple by using primer set 1F 1R. Comparisons with published sequences indicated that the isolate have very high 91 % identity values to the corresponding region of ACLSV isolate from apple. Selected primer pair (1F1R) was further used for screening 42 elite mother plants collected from apple growing areas of Himachal Pradesh, India, where in 17 were found free from ACLSV. Use of NAD5 gene in mitochondrial mRNA of the apple as an internal control, reduced the risk of false negative results that may occur with routine RT-PCR assays.