Morphology and Taxonomy of <Emphasis Type="Italic">Apristurus longicephahis</Emphasis> (Lamniformes,Seyliorhinidae)

Data on the individual variation and changes with growth in proportions and morphology are presented for the poorly known Apristurus longicephalus, and compared with those of other species. A. longicephalus is concluded to be a distinct species without synonyms, characterized by its long snout, widely separate nostrils, long caudal fin, short abdomen, very sparse teeth, and low number of monospondylous vertebrae. It is a species of small size, maturing at about 42 cm in total length.     

Scale Growth and Squamation Chronology for the Laboratory-Reared Hermaphroditic Fish <Emphasis Type="Italic">Rivulus marmoratus</Emphasis> (Cyprinodontidae)

Scale morphology, growth and the squarnation chronology are described for the hermaphroditic fish Rivulus marmoratus reared in the laboratory. The scales are round or oval shaped cycloid type, and their sizes are about 0.3–1.0 mm in diameter. The number of ridges increases more rapidly relative to the body growth of the fish in early stages, but this increase is proportionate to growth subsequently. Three loci of scale development have been identified. The scales first appeared on the center of the parietal region at 8 days after hatching. The second locus of scale formation was on the lateral line of the posterior end of the caudal peduncle. A third locus was later observed on the lower right corner of the operculum: The final squamation was completed at 6 weeks after hatching.     

尾壳核内注射脑啡肽和bestatin对大鼠操作式条件...

Female Wistar rats were trained in a Skinner-box, 30 trials per day in a dark room to establish operant defence conditioning. Training started with a light (15 s), then combined with footshock for further 8 s. When the rats learned to press the key to avoid footshock within 15 s, conditioned response was considered established. After the rats reached a conditioning rate (CR) above 80% for 5 days, cannulae were implanted into caudate-putamen. Two to three days later, Met-enkephalin (MEK) or bestatin (an aminopeptidase inhibitor) was injected bilaterally into caudate-putamen. 30 min, 2 h, 24 h and 48 h after injection, conditioning tests were conducted, with each session consisting of 30 trials. Control experiments were done when 0.9% NaCl (NS) was injected. After injection of NS, CR maintained above 80% in all 4 test sessions. MEK (60 ng/rat) or bestatin (10 micrograms/rat) significantly lowered the CR during the 30 min and 2 h test session. In the latter case, the latency (L) was also prolonged. However both CR and L returned to the control level in the 24 h and 48 h test sessions. Naloxone (2 mg/kg, i.p.) blocked the conditioning-depression effect of bestatin. No significant alteration was seen in locomotor activity after MEK or bestatin injection. The results suggest that enkephalin in caudate-putamen may be involved in the regulation of retrieval of conditioning. Bestatin mimics the effect of MEK on conditioning reflex probably by increasing production of endogenous enkephalin.     

The reconciliation behavior of golden monkeys (Rhinopithecus roxellanae roxellanae) in small breeding groups

Observations were made following 130 spontaneous aggressive incidents in two small breeding groups of captive golden monkeys (Rhinopithecus roxellanae roxellanae). Participants were observed both during the first 10 min following these incidents and during matched control observations. An increased contact rate was observed between opponents following the aggressive incident. Post-conflict contacts were characterized by a number of behavior patterns: open mouth, rapid grooming, embrace, and crouching. Adult males played an important role as mediator in agonistic disputes among females: males intervened in 93.6% of female fights. It is speculated that this intervention behavior is related to the species' organization into one-male units.     

外周损伤引起成年大鼠体感皮层的功能重组

为了了解外周神经损伤对体感皮层分域组构的影响,在成年大鼠上观察了切断坐骨神经(SC)前、即刻和切断后数周内后爪皮层代表区的改变。在盐酸氯胺酮麻醉下,用微电极记录后爪皮肤轻触刺激在对侧体感皮层工区诱发的多单位反应,得出后爪的皮层代表区图。在16例中,8例大鼠观察了切断SC的即时效应。结果表明,不但SC代表区丧失皮肤反应性,原隐神经(SA)代表区的皮肤反应性也明显下降或消失,同时神经元自发活动也明显减弱。另8例大鼠在切断后数周内做了1～3次重复测定。在最初几天,原SA代表区范围内多数记录点的皮肤反应性仍未恢复,但在原SC代表区内,一些记录点转而对SA皮肤轻触刺激起反应。在随后数周内SA代表区进行性地扩张,占领了大部分原SC代表区。这一结果说明成年大鼠外周神经损伤可导致体感皮层发生显著的重组改变。     

Cultural characteristics and zearalenone production by strains of<Emphasis Type="Underline">Fusarium</Emphasis> from wheat

Conidia of the speciesFusarium culmorum /W.G.Sm./ Sacc. andFusarium graminearum Schwabe are characterized by variability in zearalenone production and dimensions depending on the substrate. The sporulation of isolates from some wheat eultivars have been deprived in vivo and in vitro in the first passage, but not their pathogenicity and toxic metabolites production. Nonsporulating strains produced lower quantités of zearalenone than sporulating ones. Liquid filtrates of such nonsporulating strains had a high phytotoxic effect on wheat caryopses. The crystalline toxin DAS /0,25 ug/ml/ had low phytotoxic effect on wheat caryopses.     

Cumulation of mycotoxins in maize cobs infected with<Emphasis Type="Italic">Fusarium gramihearum</Emphasis>

Maize cobs withFusarium ear rot were collected at 1986 season and five infected byFusarium graminearum were analyzed for presence of triohothecenes and zearalenone. Collected material was subsampled forFusarium damaged kernels and corresponding axial stems and healthy looking kernels. All investigated cobs contained deoxynivalenol (DON) (range 18.0–131.5 mg/kg) and zearalenone (ZEA) (range 0.38–2.17 mg/kg), in four cobs 15-acetyl-deoxynivalenol (15-AcDON) (range 5.2–6.2 mg/kg) was present and two cobs besides three all metabolites contained 3-acetyl-deoxynivalenol (3-AcD0N) (range 0.5–0.8 mg/kg).The average of individual toxins amount in axial stems: in mg/kg was equal to: DON — 110.36, ZEA — 4.57, 15-AcD0N — 16.66, and 3-AcD0N — 1.32.Fusarium damaged kernels contained in average the following amount (mg/kg) of: DON 77.00, ZEA 0.98, 15-AcD0N 3.78 and 3-AcD0N 0.06. Healthy looking kernels contained DON 1.96 mg/kg and ZEA 0.07 mg/kg only. Cooccurrence of 3-AcDON and 15-AcDON in two samples was an interesting finding. The amount of DON in total cob was highly correlated (r = 0.94) with percentage ofFusarium damaged kernels in given ear.     

流行性感冒病毒重组株京生75-29 R2 T1及冷适应株31-广的基因分析

用聚丙烯酰胺凝胶电泳方法分析了流行性感冒病毒重组株京生75-29R2 T1(H3N2)及冷适应株31-广(H3N2)的RNA及多肽。重组株京生75-29R2 T1的HA及M基因系来自流行病毒亲本株/甲/北京/29/75(H3N2),而P_2、NA、NP及NS基因则来自温度敏感母株福R3(H2N2)。流行病毒株甲/穗/03/68(H3N2)在低温条件下经鸡胚尿囊腔传递24代而获得的冷适应疫苗毒株31-广(H3N2)其基因型与野毒株一致。     

苜蓿二磷酸核酮糖(RuBP)羧化酶体内活化作用的调节

苜蓿RuBP羧化酶的初活性和活化作用在不饱和光强下与光合速率一样随光强增加而增加。缺硫培养苜蓿叶片的光合速率和RuBP羧化酶的含量、初活性及总活性均比对照有不同程度的降低,其中酶的初活性与光合速率两者减少的趋势比较接近,说明RuBP羧化酶的初活性可能在光合CO_2固定作用中具有决定作用。然而,缺硫植株中酶的活化作用比对照明显增高。酶的活化作用与叶片中的叶绿素,6-PG,NADPH及ATP相对酶含量的比值成正比,与体内的酶量成反比。     

泥河湾层中新发现一处旧石器地点

半个多世纪以来,在泥河湾层中寻找早更新世时期的人类遗迹,已成为中、外许多科学家非常关心的一个问题。近几年来,在泥河湾村附近,大量古文化遗物从属于下更新统的泥河湾层中发现了。新的发现为旧石器时代考古学和第四纪地质学又增添了新的内容。