黄海沉积物多细胞趋磁原核生物的特性研究

多细胞趋磁原核生物（Multicellular magnetotactic prokaryotes，MMPs） 是一类由7～45 个含有磁小体的革兰氏阴性细胞聚集而成的球形或者椭圆形 的细胞聚集体，是研究生命起源与进化、细胞分化和生物矿化的模式生物， 目前仅在大西洋沿岸具有一定盐度的层化水体或沉积物中发现。 本文通过光学显微镜和电子显微镜研究了黄海沉积物MMPs 的超微结 构、运动特点和分裂方式等生物学特征，调查了MMPs 的生态分布特征，并 对其尝试培养。 根据形态差别，黄海沉积物的MMPs 可分为花瓣型MMPs（rosette-like MMPs）、菠萝型MMPs（pineapple-like MMPs）和松球型MMPs（pinecone-like MMPs）。花瓣型MMPs 是由23±4 个卵圆形的细胞螺旋形排列而成的球形聚 集体，直径为5.4±0.8 μm，鞭毛周生。细胞内外膜附近有子弹头形/和方形的 铁氧化物型磁小体。菠萝型MMPs 是由39±9 个方形细胞组成的大小为9.6±1.2 μm ×7.8±0.9 μm 的椭圆形聚集体，鞭毛周生。这类MMPs 由多环细胞组成的， 从椭圆体的赤道面向两极，细胞环的直径变小；在每一环内，细胞像书本似 并列相连；相邻两环的细胞为交错式相连。这种结构比花瓣型MMPs 的更为 紧密。菠萝型MMPs 的磁小体均为子弹头形铁氧化物，磁小体的排列与MMPs 的长轴近似平行。松球型MMPs 是由多个长条形的细胞围绕中心的一个凹陷 辐射排列而成的球形聚集体，直径在9.0～14.2 μm 之间。尼罗红和DAPI 染 色发现三种MMPs 均具有脂类颗粒，花瓣型MMPs 和菠萝型MMPs 在聚集体 的表面具有一层外膜，这说明MMPs 的细胞排列具有高度组织性，在一定程 度证明它属于多细胞生物。 花瓣型MMPs 和菠萝型MMPs 分裂时均保持多细胞形式，但花瓣型 MMPs 沿着聚集体的短轴分开，而菠萝型MMPs 沿着长轴分开。两种MMPs 具有MMPs 典型的逃逸运动，花瓣型MMPs 和菠萝型MMPs 的运动速度分别 为55±26 μm/s 和99±50 μm/s。 黄海花瓣型MMPs 的超微结构、运动方式和分裂特点与大西洋沿岸多个 地区发现的MMPs 相似，花瓣型MMPs 可能是MMPs 的优势类群。菠萝型 MMPs 从整体形态、细胞排列和分裂方式上与花瓣型MMPs 显著不同，是一 类新的MMPs。松球型MMPs 是一类尚未报道的MMPs。 对MMPs 的生态分布调查发现，花瓣型MMPs 广泛分布于砂质沉积物中， 最大丰度出现在氧化还原跃层（redoxcline）。菠萝型MMPs 多分布在砾石沉 积物的表层。两种MMPs 占据不同的生态位，暗示着两者可能具有不同的生 理代谢途径。 对MMPs 的培养发现，在实验室内MMPs 可存活8 个月，MMPs 丰度随 着时间变化出现周期性的变化，推测其繁殖周期可能是10～15 天。 本文为太平洋沿岸MMPs 的首次研究，支持MMPs 在全球广泛分布的观 点，并展示了MMPs 的形态多样性。

Pelagic fishery resources of Sri Lanka and its present level of exploitation with special reference to off-shore and deep-sea waters

Pelagic resources around Sri Lanka may be categorized into three major groups: (1) the small pelagic varieties such as the sprats, halmessa, sardines (salaya, soodaya), and herrings (hurulla). (2) the medium size pelagic species such as the mackerel (kumbala and bolla), barracuda (jeela), seer Spanish mackerel (thora), frigate mackeral (alagoduwa), mackerel tuna (atawalla) and the skipjack (balaya). (3) the large size fishes such as yellow fin tuna (kelawalla), big eye tuna, marlins (koppora and gappara), sail fish (thalapath), sharks (mora) and rays (maduwa). Production levels of exploited resources are noted, and seasonal patterns and annual in their abundance are considered. On the basis of observations and estimations of the existing fisheries, and the results of experimental fishing, figures are presented of the potential yield of those species already exploited. The development of that potential depends on the development of modern techniques of pole and line fishing, application of tuna longline and shark longline, increasing the number of units of drift nets and the introduction of a bait fishery for the longline and pole line fishery. Some features upon which the successes of any venture to exploit such resources are noted, particularly those which relate to the nature of the fishing vessels used.

Fishing gear and methods for off-shore fishing in Sri Lanka

The author describes the commercial viable off-shore fishing methods for catching known commercial resources available around Sri Lanka. He also describes the in-shore fishing methods such as bait fishery which are related and of prime importance for carrying out certain off-shore methods. The paper is intended as a background for the description of fishing methods. The methods discussed are: (1) Longlining for large pelagic species such as large tuna (yellow fin, big eye), shark, spearfish and others; (2) Drift-netting for small and large tuna species (skipjack, yellow fin and others), shark, spearfish, etc.; (3) Pole and line for all deep-sea pelagic species such as skipjack, yellow fin, frigate mackerel, etc.; and (4) Purse seining (small scale) for small pelagic species suitable as bait fish for pole and line and longline fisheries.

Y chromosome haplotypes reveal prehistorical migrations to the Himalayas

By using 19 Y chromosome biallelic markers and 3 Y chromosome microsatellite markers, we analyzed the genetic structure of 31 indigenous Sino-Tibetan speaking populations (607 individuals) currently residing in East, Southeast, and South Asia. Our results showed that a T to C mutation at locus M122 is highly prevalent in almost all of the Sino-Tibetan populations, implying a strong genetic affinity among populations in the same language family. Furthermore, the extremely high frequency of H8, a haplotype derived from M122C, in the Sino-Tibetan speaking populations in the Himalayas including Tibet and northeast India indicated a strong bottleneck effect that occurred during a westward and then southward migration of the founding population of Tibeto-Burmans. We, therefore, postulate that the ancient people, who lived in the upper-middle Yellow River basin about 10,000 years ago and developed one of the earliest Neolithic cultures in East Asia, were the ancestors of modem Sino-Tibetan populations.

Flavobacterium anhuiense sp nov., isolated from field soil

A novel strain, D3(T), isolated from a field-soil sample obtained from Anhui Province, PR China, was characterized taxonomically by using a polyphasic approach. The cells were Gram-negative, yellow-pigmented rods devoid of flagella, but showing gliding motility. The organism was able to grow at 5-37 degrees C and at pH 4.0-10.0. A comparative 16S rRNA gene sequence analysis indicated that strain D3(T) is a member of the genus Flavobacterium, sharing highest sequence similarity with the type strain of Flavobacterium defluvii (96.7 %). The major isoprenoid quinone was MK-6 and the predominant fatty acids were iso-C-15:0, summed feature 3 (C-16:1 omega 7c and/or iso-C-15:0 2-OH) and C-16:0. The DNA G + C content was 31.4 mol%. On the basis of phylogenetic and phenotypic data, strain D3(T) represents a novel species within the genus Flavobacterium, for which the name Flavobacterium anhuiense sp. nov. is proposed. The type strain is D3(T) (=KCTC 22128(T)= CGIVICC 1.6859(T)).

Studies on smoke curing and preservation of oil sardine (Sardinella longiceps)

A method is reported for smoke curing of oil sardine (Sardinella longiceps) by dry salting in the ratio of 1:6 (salt to fish), followed by smoking in the traditional smoke chamber in two stages, (1) at 45°C for 3h hand (2) at 75°C for 2h with smoke generated from coconut husk, wood shavings and saw dust in 2:2:1 proportion. The product obtained had good odour, flavour, golden yellow colour and a shelf-life of 8 weeks at room temperature (26 to 28°C)

Effect of colour on the catch of gill nets

The effect of white, green, blue and yellow coloured drift gill nets on their catch with respect to Scomberomorus guttatus (Schneider), Scomberomorus commerson (Lacepede), Scomberomorus lineolatus (Cuvier), Parastomateus niger (Bloch), Euthynnus ajjinis (Cantor) and sharks Carcharius melanopterus is discussed. White nets were more effective for S. guttatus while the coloured ones caught more of P. niger. Blue had no significant effect for sharks. In the case of S. lineolatus, S. commerson and E. affinis no preference to colour was noted.

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.

Catch efficiency and selective action of coloured gill nets

Information on the catch efficiency and selective action of coloured gill nets in relation to the reservoir fishes of India are lacking. Authors, in the present studies have attempted to evaluate the comparative catch efficiency of gill nets of four shades viz. yellow, orange, green and blue over the colourless ones, by conducting fishing experiments, in the Govindsagar reservoir. Attempts have also been made to study the preference shown to colours by the four major species of fishes of the reservoir.

Coloured gill nets for reservoir fishing

Experimental fishing with different coloured nets has shown that white net yields better catch. The efficiency of the coloured nets was in the order yellow, grey, green and blue. Though there is little evidence to show some species preference to a particular colour, the results were not conclusive as the analysis of variance indicated that interaction between species and colour is significant only at 5% level.

Studies on the effect of colour of webbing on the efficiency of gill nets for hilsa and pomfret off Veraval

Influence of colour of webbing on the catch of gill nets for commercially important hilsa (Hilsa toli and Hilsa ilisha) and pomfret (Pampus argenteus and Parastromateus niger) has been studied in the coastal waters off Veraval. Among the colours tested yellow and white are recommended for hilsa and pomfret gear. Influence of fishing depth, surface water temperature and turbidity on catch are also discussed.

A re-description of the little known rabbit fish Siganus lineatus (Cuvier and Valenciennes) (Pisces:Siganide) with notes on siganid fishes of the Vembanad Lake

Siganus lineatus (Cuv. and Val) is reported from the coast of peninsular India for the first time and a detailed description of it is given based on morphology and meristic characters. It differs from the other allied species of the genus Siganus Forskal in having an oval body without spots and having fifteen parallel longitudinal golden yellow bands, relatively larger last dorsal spine, maxillary position far below the level of the orbit and cheek with distinct rows of scales. S. javus (Linnaeus) and S. canaliculatus (Park) were also obtained from the Vembanad Lake. Short notes on the habitat, occurrence, abundance, seasonal and geographic distribution in relation to fluctuating hydrological conditions of the Vembanad Lake are incorporated together with a key for their identification.

Studies on frozen storage of cuttle fish fillets

The freezing and cold storage characteristics of cuttle fish fillets have been studied. The yield of fillets from cuttle fish was about 35% and the fillet had an average moisture content of 76.85% and fat 0.82% During storage at -20 ± 1°C for 16 months the salt soluble nitrogen of the fillets decreased from 85.1to35.36%, the non-protein nitrogen from 24.61 to 20.84% and alpha amino nitrogen from 252 to 140mg/100g. Initially the fillets were white in colour, showed signs of desiccation by 4 months storage which increased on further storage and the fillets finally became dull white with yellow discolouration inside. The firm and chewy texture of the cooked fillets changed to rubbery even though the product was slightly sweet at the end of that storage period of 16 months.

Fish sauce from two species of unexploited deep sea fish Peristedion adeni and Peristedion weberi

Two species of unexploited deep sea fish Peristedion adeni and Peristedion weberi caught from the Exclusive Economic Zone of India were subjected to fermentation at ambient temperature (30 ± 2°C) in the presence of salt in 4:1 ratio. Periodical analysis of the fermented product was carried out up to one year. The sauces had brownish yellow colour and conformed to special grade of the standards prescribed by the Food and Drug Administration. Further solubilization of protein after 9 month's maturation was not appreciable.