Studies on radiation pasteurisation of medium fatty fish 1. Control of radiation induced oxidative changes in white pomfret (Stromateus cinereus) by vacuum packaging

Marked differences were observed in proximate biochemical compositions of the skin and muscle of white pomfret. The skin showed comparatively higher content of extractable lipids and was more susceptible to radiation-induced oxidative changes like development of rancid odours and yellow discolouration than the muscle. Irradiation of skin samples under vacuum suppressed these changes. The present paper also reports on the efficacy of vacuum packaging in controlling oxidative rancidity and yellow discolouration in white pomfret skin subjected to irradiation and subsequent storage at 0-2°C.

Studies on radiation pasteurisation of medium fatty fish 3. Storage properties of white pomfret (Stromateus cinereus) fillets

White pomfret fillets packed under aerobic conditions had a limited shelf life of 8 days as against 10 days for samples packed under vacuum and stored at 0-2°C. Irradiation and subsequent storage of the fillets under vacuum at 0-2°C exhibited shelf lives of 30, 50 and 60 days for radiation doses of 0.1, 0.3 and 0.5 Mrad respectively in contrast to aerobically packed fillets which showed only 20, 35 and 50 days of storage life for the same levels of radiation doses and developed yellow discolouration and rancid odours.

Studies on radiation pasteurisation of medium fatty fish 2. Precursors of yellow discolouration in irradiated white pomfret (Stromateus cinereus)

Triglycerides, phospholipids and sarcoplasmic proteins fractions of white pomfret produced considerable amounts of thiobarbituric acid reactive substances (TBRS) on irradiation. Incubation of malonaldehyde with pomfret skin under aseptic conditions developed yellow pigmentation of the skin tissues, similar in spectral characteristics to those produced on irradiation of the skin.

Biochemical differences between the red and white meat of tuna and changes in quality during freezing and storage

The differences between the white and red (dark) meat of tuna (Katsuwonus pelamis) in chemical, physical and organoleptic aspects and the rate and pattern of spoilage during freezing and subsequent storage are discussed in this communication. In the indices studied distinct difference is seen between the white and red meat as well as in the head, middle and tail portions of the same fish. The characteristic colour of tuna meat is due to the presence of haemoglobin and myoglobin, the concentrations of which are about 5 times more in red meat than in white meat. The shelf-life of the frozen material varies with the type of the pack, that is, whole fish>chunks>fillets; the fillets being adversely affected during frozen storage.

Taxonomic status of the white-head langur (Trachypithecus francoisi leucoscephalus) inferred from allozyme electrophoresis and random amplified polymorphism DNA (RAPD)

Six sample specimens of Trachypithecus francoisi and 3 of T. leucocephalus were analyzed by use of allozyme electrophoresis and random amplified polymorphism DNA (RAPD) in order to clarify the challenged taxonomic status of the white-head langur. Among the 44 loci surveyed, only 1 locus (PGM-2) was found to be polymorphic. Nei's genetic distance was 0.0025. In total, thirty 10-mer arbitrary primers were used for RAPD analysis, of which 22 generated clear bands. Phylogenetic trees were constructed based on genetic distances using neighbor-joining and UPGMA methods. The results show that T. francoisi and T: leucocephalus are not monophyletic. T. francoisi from Guangxi, China and Vietnam could not be clearly distinguished, and they are not divided into 2 clusters. A t-test was performed to evaluate between genetic distances within and between T. leucocephalus and T. francoisi taxa groups. The statistical test shows that the taxa group within T: leucocephalus and T: francoisi does not significantly differ from that between T: leucocephalus and T: francoisi at the 5% level. Our results suggest that the level of genetic differentiation between T, leucocephalus and T. francoisi is relatively low. Recent gene flow might exist between T. francoisi and T. leucocephalus. Combining morphological features, geographical distribution, allozyme data, RAPD data, and mtDNA sequences, we suggest that the white-head langur might be a subspecies of T. francoisi.

脊胸天牛(Rhytidodera bowringii White)在杧果树枝干的分布研究

本文研究了果树害虫脊胸天牛（ＲｈｙｔｉｄｏｄｅｒａｂｏｗｒｉｎｇｉｉＷｈｉｔｅ）在云南景谷县果国内对果树枝干的分布和危害情况。结果表明，该害虫在三年和象牙树上主要危害３～５年生枝条，其有虫枝率分别为６５．３％和９２．０％。另外，按地形将果园分为上、中、下三个区带，分别调查各区活枝、地面枯枝和腐枝中的害虫。结果显示，中区活枝、枯枝、腐枝的有虫枝率分别为６０．０％，３０．０％和１７．０％，其有虫枝率分别高于果园的上区和下区。总体上看，三个区带活枝、枯枝和腐枝的有虫枝率分别为５６．８％，３４．０％和１４．３％。定期清除果国内的枯枝和腐枝是防治脊胸天牛的有效措施之一。

脊胸天牛(Rhytidodera bowringii White)生物学及其防治研究

脊胸天牛是云南芒果树的主要害虫之一。在云南景谷地区两年发生一代, 三年完成, 世代交叉, 因此为害特别严重。通过综合防治, 可基本控制该虫的为害。