沙棘——弗氏放线菌共生固氮体系研究——Ⅰ环境因子影响沙棘结瘤和生长

环境因子包括盐度、pH值、化合氮和磷素供给显著影响了Frankia菌株Hr32对水培沙棘小苗的侵染结瘤。沙棘能在0.8％盐度下生长但受抑,0.2％盐度下开始有根瘤发生,0.1％盐度下结瘤较好。Hr32纯培养下耐盐力不强,0.5％盐度下已不能生长,导致了高盐浓度下不能结瘤。pH=7.0—8.0为沙棘结瘤最佳范围,pH值高至9.0或低至4.2,沙棘不能结瘤。低磷供给限制了根瘤发生,当供给10ppm或更高的磷时,沙棘成功结瘤。低于6ppm化合氮供给促进结瘤,当供给16ppm化合氮时,结瘤完全抑制。结瘤使沙棘获得近二倍的增长效果,水培条件下人工根瘤活性低于自然生境根瘤。结瘤使沙棘的落叶延迟。     

The effect of selenium and vitamin E on microvascular permeability of rat organs

The effects of dietary sodium selenite and vitamin E on the microvascular permeability of rat organs such as heart, brain, kidney, liver and eye were investigated by using the Evans blue leakage method. Combined deficiency of selenium and vitamin E caused an increase in the permeability of the heart and eye with respect to their controls while it had no considerable effect on the permeability of other organs. On the other hand, toxic levels of selenium (4.2 mg/kg) in diet decreased the permeabilities in kidney, liver, and eye whereas this parameter of brain increased in the same animal group. These results suggested that low or high sodium selenite and vitamin E contents in diet could alter the microvascular permeability of different organs in different manners. It might be important to give reasonable explanations for the pathophysiology of some diseases that are characterized with organ damage and /or disfunction originated from selenium deficiency or toxicity.     

chs-4, a class IV chitin synthase gene fromNeurospora crassa

InSaccharomyces cerevisiae, most of the cellular chitin is produced by chitin synthase III, which requires the product encoded by theCSD2/CAL1/DIT101/KT12 gene. We have identified, isolated and structurally characterized aCSD2/CAL1/DIT101/KT12 homologue in the filamentous ascomyceteNeurospora crassa and have used a “reverse genetics” approach to determine its role in vivo. The yeast gene was used as a heterologous probe for the isolation of aN. crassa gene (designatedchs-4) encoding a polypeptide belonging to a class of chitin synthases which we have designated class IV. The predicted polypeptide encoded by this gene is highly similar to those ofS. cerevisiae andCandida albicans. N. crassa strains in whichchs-4 had been inactivated by the Repeat-Induced Point mutation (RIP) process grew and developed in a normal manner under standard growth conditions. However, when grown in the presence of sorbose (a carbon source which induces morphological changes accompanied by elevated chitin content), chitin levels in thechs-4 ^RIP strain were significantly lower than those observed in the wild type. We suggest that CHS4 may serve as an auxiliary enzyme inN. crassa and that, in contrast to yeasts, it is possible that filamentous fungi may have more than one class IV chitin synthase.     

Enhancement of biological treatment performance of saline wastewater by halophilic bacteria

Performances of biological treatment processes of saline wastewater are usually low because of adverse effects of salt on microbial flora. High salt concentrations in wastewater cause plasmolysis and loss of activity of cells resulting in low COD removal efficiencies. In order to improve biological treatment performance of saline wastewater, a halophilic organism Halobacter halobium was used along with activated sludge culture.A synthetic wastewater composed of diluted molasses, urea, KH₂PO₄ and various concentrations of salt (1%–5% NaCl) was treated in an aerobic-biological reactor by fed-batch operation. Activated sludge culture with and without Halobacter were used as seed cultures. Variations of COD removal rate and efficiency with salt concentration were determined for both cultures and results were compared. Inclusion of Halobacter into activated sludge culture resulted in significant improvements in COD removal efficiency. A rate expression including salt inhibition effect was proposed and kinetic constants were determined by using experimental data.This study was supported by the Technical and Scientific Research Council of Turkey.     

ECOLOGICAL SEPARATION BETWEEN WHITE AND PINK-BACKED PELICANS IN THE RUWENZOFU NATIONAL PARK, UGANDA

The number and distribution of the White Pelican Pelecanus onocrotalus roseus and the Pink-backed Pelican P. rufescens were studied in the Ruwenzori National Park, Uganda, by means of aerial surveys carried out at approximately weekly intervals between May 1968 and December 1969. The White Pelican is migratory and was present in the Park at highest numbers in August 1968 and May 1969 when 2510 and 3927 respectively were recorded. It does not breed within the Park. The Pink-backed Pelican is resident, with a population averaging about 1350 birds. Pelicans are distributed in discrete flocks on loafing grounds. Flocks of the White Pelican tend to be bigger than those of the Pink-backed. Forty-three loafing grounds were recognized in the Park, and it is shown that there is no difference between the species in the frequentation of these grounds. The areas favoured by both species are characterized by flat, open stretches close to water; steep slopes and heavily vegetated shore-lines are avoided. The feeding behaviour was studied by direct observation and through cine-photography. Only the White Pelican feeds communally in coordinated groups; this species also often feeds singly. The feeding sequence of both species is described, and is divided into four phases:searching, trapping, catching and swallowing. The searching phase lasts about six times longer in the Pink-backed Pelican than in the White. The White Pelican feeds further from the shore than does the Pink-backed. There is little difference between the species in the daily feeding pattern. Feeding takes place throughout the day but mostly from dawn to about 10.00 hrs and from 17.00 hrs until dusk. The rest of the day is spent mainly in preening, resting or bathing. The food of pelicans is exclusively fish. The White Pelican takes mainly large Tilupia, and Haplochromis and fish fry to a lesser extent. The Pink-backed Pelican feeds largely on fish fry, but Tilapia and Haplochromis are frequently taken and by weight are more important than the fry. However, the Tilapiu are smaller than those taken by the White Pelican. Ecological separation between the two species is achieved through these differences in their feeding behaviour. It is estimated that the White Pelican takes 1201 g and the Pink-backed Pelican 776 g of fish each day. The total amount of fish eaten by both species from Lake George during 1969 was calculated to be 591 709 kg. This is small (c. 3%) compared with the estimated total fish production of the lake but quite appreciable (12.7%) as a proportion of the total caught by man. It is concluded that the pelican populations are probably not important as a link in the chain whereby organic matter transferred from land to water by the Hippopotamus is returned to the land.     

Exploring the abundance and DNA barcode information of eight parasitoid wasps species (Hymenoptera), the natural enemies of the important pest of oil palm,bagworm, Metisa plana (Lepidoptera: Psychidae) toward the biocontrol approach and it's application in Malaysia

Parasitoid wasps (Hymenoptera) play a significant role in reducing the pest population of the bagworm species Metisa plana. This study presents the abundance and DNA barcoding information of eight parasitoid wasps species, Dolichogenidea metesae (47%), Brachymeria carinata (19%), Buysmania oxymora (12%), Goryphus bunoh (7%), Pediobius anomalus (5%), Eupelmus cotoxanthae (2%), Apanteles aluella (5%), Apanteles sp.1 (3%) and that emerged from M. plana collected from three highly infested oil palm plantations in Selangor (west), Perak (north) and Johor (south) in Peninsular Malaysia. Samples of infested M. plana were collected from the field and reared in a rearing room. The parasitoid wasp species D. metesae recorded the highest emergence numbers and the broadest presence in all the sampling sites. The relationships among the parasitoids species were estimated and visualized using Neighbor Joining (NJ) phylogenetic analyses with the Ceraphronidae family as an outgroup. The resulting NJ tree showed that the identified parasitoid wasps were successfully classified into specific species and supported with bootstraps values between 55% to 100%. This study provides important information on potential biological control agents for M. plana that may be useful for the Malaysian oil palm industry.     

The social development of baboons in their first three months

The development of the mother-infant relationship is expressed in terms of the change in typical relative positions of the pair and in the pattern of contacting and leaving they showed.
Rainy periods increased the time the infant spent asleep with its mother, the effect being more than that produced by the infant's age on sleeping time in the first three months of life.
Rate of development of mother-infant relationships was compared with that of Rhesus monkeys in similar conditions, and found to be very closely comparable.
Interactions by infants with other baboons were found to be quantitatively and qualitatively different for each available demographic class (though some classes were only represented by a single individual). Results illustrated different rates of social maturing in the sexes, differential behaviour of the adult male towards the sexes of infants, and the existence of a special relationship between siblings.
Interactions of neoparturient mothers with other adults are characterized by high overall frequency, with a high frequency of avoiding of friendly approaches by the mother. Both these have returned to normal frequency levels in the third month.
Restriction of infants by mothers was seen only in the caged group. Its immediate effects on the behaviour of the infant and its association with other maternal social behaviour are described.     

Arsenic and heavy metals health risk assessment through drinking water consumption in the Peshawar District,Pakistan

This study aimed to assess the drinking water quality and human potential health risk in Peshawar, which is the most populous district of Khyber Pakhtunkhwa Province, Pakistan. Water was randomly collected throughout Peshawar District (urban = 45 samples and rural = 29 samples). These samples were analyzed for heavy metal (As, Cd, Co, Cu, Cr, Hg, Ni, Pb, and Zn) concentrations using the atomic absorption spectrometer (Perkin Elmer, AAS-PEA-700). Heavy metal concentrations in drinking water revealed the highest pollution index (PI) values—17.80, 11.92, 7.50, and 5.70 for the Pb, Cr, Cd, and Ni, respectively. The contaminations of Cd and Pb were significantly higher (p < .05) than their maximum allowable limits set by the World Health Organization. Heavy metal contaminations in drinking water were evaluated for health risk assessment: the chronic risk or hazard quotient (HQ) and cancer risk. Results revealed that HQ values were >1 for the Cd and Pb, suggesting that the exposed human beings could be at chronic risk. Therefore, serious measures such as drinking water treatments and contamination controlling policies are needed to avoid the hazardous effects of toxic heavy metals.     

The efficient role of aquatic plant (water hyacinth) in treating domestic wastewater in continuous system

In this study, water hyacinth (Eichhornia crassipes) was used to treat domestic wastewater. Ten organic and inorganic parameters were monitored in three weeks for water purification. The six chemical, biological and physical parameters included Dissolved Oxygen (DO), Biological Oxygen Demand (BOD), Chemical Oxygen Demand (COD), Ammoniacal Nitrogen (NH₃-N), Total Suspended Solids (TSS), and pH were compared with the Interim National Water Quality Standards, Malaysia River classification (INWQS) and Water Quality Index (WQI). Between 38% to 96% of reduction was observed and water quality has been improved from class III and IV to class II. Analyses for Electricity Conductivity (EC), Salinity, Total Dissolved Solids (TDS) and Ammonium (NH₄) were also investigated. In all parameters, removal efficiency was in range of 13–17th day (optimum 14th day) which was higher than 3 weeks except DO. It reveals the optimum growth rate of water hyacinth has great effect on waste water purification efficiency in continuous system and nutrient removal was successfully achieved.     

Leptin promoter variant G2548A is associated with serum leptin and HDL-C levels in a case control observational study in association with obesity in a Pakistani cohort

Leptin is a protein hormone synthesized by adipocytes and is involved in the regulation of food intake and energy expenditure. We hypothesized that any change in the promoter sequence can affect the expression of the gene and hence leptin protein levels in the serum. The aim of the current study was to investigate the relationship of such a promoter variant of the leptin gene, G-2548A polymorphism, with obesity and its effect on various anthropometric and metabolic parameters in a Pakistani cohort consisting of 250 obese and 225 non-obese control subjects. Body weight, height, waist circumference (WC), hip circumference (HC) and blood pressure (BP) were measured by standard methods and levels of fasting blood glucose (FBG), total cholesterol, triglycerides, HDLC, LDLC, and leptin were determined. Genotyping was done by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). The results showed that the LEP G-2548A polymorphism showed significant association with obesity in Pakistan. In addition, the polymorphism showed association with weight, height, BMI, WC, HDLC and serum leptin levels. The findings suggest that the leptin promoter G-2548A variant may play its part in the progression to obesity by not only affecting the body’s fat distribution but also by changing the serum leptin and HDLC levels.