Period Of Active Growth Research Articles

Differential gene expression profiling through transcriptome approach of Saccharum spontaneum L. under low temperature stress reveals genes potentially involved in cold acclimation.

Sugarcane (Saccharum sp.) is predominantly grown in both tropics and subtropics in India, and the subtropics alone contribute more than half of sugarcane production. Sugarcane active growth period in subtropics is restricted to 8-9months mainly due to winter's low temperature stress prevailing during November to February every year. Being a commercial crop, tolerance to low temperature is important in sugarcane improvement programs. Development of cold tolerant sugarcane varieties require a deep knowledge on molecular mechanism naturally adapted by cold tolerant genotypes during low temperature stress. To understand gene regulation under low temperature stress, control and stressed (10°C, 24h) leaf samples of cold tolerant S. spontaneum IND 00-1037 collected from high altitude region in Arunachal Pradesh were used for transcriptome analysis using the Illumina NextSeq500 platform with paired-end sequencing method. Raw reads of 5.1GB (control) and 5.3GB (stressed) obtained were assembled using trinity and annotated with UNIPROT, KEGG, GO, COG and SUCEST databases, and transcriptome was validated using qRT-PCR. The differential gene expression (DGE) analysis showed that 2583 genes were upregulated and 3302 genes were down-regulated upon low temperature stress. A total of 170 cold responsive transcriptional factors belonging to 30 families were differentially regulated. CBF6 (C-binding factor), a DNA binding transcriptional activation protein associated with cold acclimation and freezing tolerance was differentially upregulated. Many low temperature responsive genes involved in various metabolic pathways, viz. cold sensing through membrane fluidity, calcium and lipid signaling genes, MAP kinases, phytohormone signaling and biosynthetic genes, antioxidative enzymes, membrane and cellular stabilizing genes, genes involved in biosynthesis of polyunsaturated fatty acids, chaperones, LEA proteins, soluble sugars, osmoprotectants, lignin and pectin biosynthetic genes were also differentially upregulated. Potential cold responsive genes and transcriptional factors involved in cold tolerance mechanism in cold tolerant S. spontaneum IND 00-1037 were identified. Together, this study provides insights into the cold tolerance to low temperature stress in S. spontaneum, thus opening applications in the genetic improvement of cold stress tolerance in sugarcane.

Grazing, abandonment and frequent mowing influence the persistence of the steppe marmot, Marmota bobak

Abstract The goals of the study were to illustrate how parameters of steppe marmot settlements change after abandonment of livestock grazing, to evaluate differences in vegetation characteristics between grazed and abandoned habitats, to find the links between these characteristics and the persistence of marmot settlements and to establish whether it is possible to maintain the food base of marmots by applying frequently repeated mowing. Data were collected in 1991-2016 in the steppe marmot (Marmota bobak) settlement in the Regional Landscape Park “The Velykyi Burluk-Steppe” (Kharkiv Region, Northeastern Ukraine). We found that grazing prolongs the period of active plant growth and supports a regrowth during periods of intensive feeding of all age groups of marmots. In abandoned habitats the vegetation period ended before the end of active feeding of reproductive females and juveniles. This resulted in lower reproductive success, which determines a decrease in the population and may in the future result in a larger decline of settlements. Frequently repeated mowing by a lawnmower at a cutting height of 6-9 cm prolongs the vegetation period and maintains a water content in the plants similar to that of grazed habitats throughout the active season of steppe marmots.

Specifics of productivity formation of brоwn mustаrd sowings

Purpose. To find out the specifics of productivity formation in brоwn mustаrd at the different ways of sowing, timing of sowing and seeding rate under the conditions of the Right Bank Forest-Steppe. Methods. During the research, typical methodologies for research in agronomy were used. Results. The results on the peculiarities of the productivity formation in brоwn mustаrd are given. The content of dry matter in plants was determined by the main macrostages of brоwn mustаrd development. The most active accumulation of dry matter in plants occurs during the period of active growth (stem development – flowering) and somewhat slower at the end of the vegetation. The largest amount of it at all stages of development was noted on the crops of the second period of sowing. Reducing the dry matter content of plants in the third term was primarily due to the reduction of the vegetation period, as well as the increase of potassium content, which increases the concentration of cellular juice, osmotic pressure of cells, their moisture content, thereby reducing the dry matter content of the plant. It was found that the weather conditions of 2016 were more favourable for the growth and development of brоwn mustаrd. The average yield of the crop was higher by 0.1–0.32 t/ha as affected by the experimental treatment compared to the results of 2015 and 2017. The highest yield was obtained at the combination of seeding rate of 2.0 million seeds per hectare and a linear method of sowing. In the years favourable for the development of the crop, sowing rate can be reduced to 1.5 million seeds per hectare. Analysis of the data suggests that the oil content is largely affected by the timing of seeding, and to a lesser extent, by the seeding rate and seeding method. Conclusions. The maximum dry matter and the highest yield of brоwn mustаrd was formed when sowing in the I–II decade of April by the typical seeding method at the soil temperature of +6–7 °C and a depth of 10 cm and the and a seeding rate of 2.0 million seeds per hectare. When seeding was carried out in a broad-row way, the seed rate should be 1.5 million seeds per hectare. The maximum yield of oil per unit area was provided by the usual routine method of sowing in the I–II decade of April and the seed rate of 2.0 million seeds per hectare.

Galaxy growth in a massive halo in the first billion years of cosmic history.

According to the current understanding of cosmic structure formation, the precursors of the most massive structures in the Universe began to form shortly after the Big Bang, in regions corresponding to the largest fluctuations in the cosmic density field. Observing these structures during their period of active growth and assembly-the first few hundred million years of the Universe-is challenging because it requires surveys that are sensitive enough to detect the distant galaxies that act as signposts for these structures and wide enough to capture the rarest objects. As a result, very few such objects have been detected so far. Here we report observations of a far-infrared-luminous object at redshift 6.900 (less than 800 million years after the Big Bang) that was discovered in a wide-field survey. High-resolution imaging shows it to be a pair of extremely massive star-forming galaxies. The larger is forming stars at a rate of 2,900 solar masses per year, contains 270 billion solar masses of gas and 2.5 billion solar masses of dust, and is more massive than any other known object at a redshift of more than 6. Its rapid star formation is probably triggered by its companion galaxy at a projected separation of 8 kiloparsecs. This merging companion hosts 35 billion solar masses of stars and has a star-formation rate of 540 solar masses per year, but has an order of magnitude less gas and dust than its neighbour and physical conditions akin to those observed in lower-metallicity galaxies in the nearby Universe. These objects suggest the presence of a dark-matter halo with a mass of more than 100 billion solar masses, making it among the rarest dark-matter haloes that should exist in the Universe at this epoch.

Экспериментальная оценка влияния 2-этил-6-метил-3-гидроксипиридина сукцината (мексидола) на растущий организм

Представлены результаты исследования токсичности 2-этил-6-метил-3-гидроксипиридина сукцината (мексидола) при длительном пероральном введении молодым животным (крысята). Данные биохимических исследований крови животных, получавших исследуемый препарат в дозе, соответствующей максимальной суточной, в течение 15, 30 и 60 дней, свидетельствуют об отсутствии выраженного токсического действия мексидола на организм в период активного роста.

The effects of burning season and severity on the mortality over time of Pinus nigra spp. salzmannii (Dunal) Franco and P. sylvestris L.

Abstract Understanding tree mortality after fires can be used to improve planning of prescribed burning and post-burning salvage logging. This study aims to assess the effects of burning season, fire severity and tree size on the evolution of post-burning mortality of pine species with different fire resistance traits. In 2013, two paired plots (1 ha each) were burned, one in spring and the other in fall, in two mixed-stands of P. sylvestris and P. nigra, and the fire severity and tree size variables were measured. Mortality was assessed individually in a total of 933 pines during the following 3 years post-burning. We modeled the initial (1 year post-burning) and delayed (3 years post-burning) tree mortality using Firth logistic regression and Conditional Inference trees. The probability of dying after burning was lower in P. nigra than in P. sylvestris confirming that P. nigra has higher fire-resistance compared to the moderate fire-resistance of P. sylvestris . Initial mortality was slightly higher for pines burned in spring than for those burned in fall; however, after 3 years the proportion of pines that had died after the fall burns was higher than that after the spring burns. Nevertheless, for the two periods modeled, the likelihood of a pine dying was significantly higher in spring than in fall given a certain level of crown scorch. This suggests that pines with damaged crowns were more likely to die when burning occurred during periods of active growth. However, the higher fire severities at the base of the trees that occurred during the fall burns compared to the spring burns are probably the cause of the higher rates of delayed tree mortality. Higher likelihood of mortality in trees burned in fall, with higher percentages of white ashes in the stem base suggest basal stem girdling as a cause of delayed pine mortality. We can conclude that crown damage is more detrimental when burning occurs during the growth season, while longer combustion times during fall burns may have caused the higher delayed pine mortality in comparison with spring burns.

Carbon dynamics of a warm season turfgrass using the eddy-covariance technique

Despite their ubiquitous presence in the urban landscape throughout the United States, scant attention has been given to evaluate the magnitude of net carbon balance from turfgrasses. Warm season turfgrasses, in particular, have largely been understudied for their carbon sequestration potential. With questions being frequently raised on the environment friendliness of warm season turfgrasses, detailed and robust studies focusing on the carbon behavior of such systems are warranted. This study delves into the carbon balance of ‘Tifway’ bermudagrass, the extensively used warm-season turfgrass in Georgia and other subtropical and warm temperate areas. Using the eddy-covariance method, the amount of CO2 captured by a highly managed turfgrass system was measured by deploying two eddy-covariance systems for the study period of 31 months. The results show that ‘Tifway’ bermudagrass is a net sink of carbon, sequestering it at the rate of 4.51–5.15MgCha−1 yr−1. The turf canopy as well as management activities carried out in the farm appear to have a powerful influence on the carbon behavior of the turf. Seasonal and monthly fluxes suggest that turf is an efficient assimilator of carbon during its active growth period of summer and fall months. The results show that the turf sequestered higher amounts of carbon than many agricultural crop systems, supporting the assertion that it is an efficient assimilator of atmospheric carbon.

Labile carbon 'primes' fungal use of nitrogen from submerged leaf litter.

Microbial decomposers colonising submerged leaf litter are in close spatial proximity with periphytic algae and can use carbon (C) exudates released during photosynthesis. We investigated whether labile C delivered as algal exudates could affect the microbial colonisation and decomposition of leaf litter. Using microcosms, we submerged leaf litter in pond water and monitored fungal and bacterial growth over time and tested the effect of algal photosynthetic exudates by comparing microcosms in light and dark. In order to experimentally assign the effect of algal products to labile C delivery and test for a C driven mechanism, we ran a parallel experiment with microcosms in the dark where we mimicked the delivery of algal labile C by continuously adding glucose. Labile C delivered as algal exudates or glucose resulted in a dominance of fungal decomposers over bacteria, and stimulated the acquisition of more N-rich OM fractions from litter during periods of active fungal growth. Our results highlight that labile C stimulates fungal decomposers and increases N removal from leaf litter. Since fungal necromass is more resistant to degradation than bacterial, we expect that a fungal-dominated litter degradation might contribute to more protected C pools.

Modulation of gene expression by nutritional state and hormones in Bombyx larvae in relation to its growth period

Insect growth and development are mainly regulated via synchronization of many extrinsic and intrinsic factors such as nutrition and hormones. Previously we have demonstrated that larval growth period influences the effect of insulin on the accumulation of glycogen in the fat body of Bombyx larvae. In the present study we demonstrate that Bombyx larvae at the terminal growth period (TGP, after critical weight) had a significantly greater increase in the expression level of Akt in the fat body than at the active growth period (AGP, before critical weight). The larvae at TGP also showed an increase in the expression level of ecdysone receptors (EcRB1 and USP1) and ecdysone-induced early genes (E75A and broad). The treatment of bovine insulin and methoprene to larvae at AGP induced the transcript levels of Akt, irrespective of the nutritional status of the larvae. However, in larvae at TGP, insulin repressed the transcript level of Akt. On contrary, 20-hydroxyecdysone (20E) induced the expression level of Akt in TGP larvae, but at feeding only. Insulin and 20E thus showed an antagonistic action on the Akt expression level in TGP larvae under feeding. The studies thus showed that larval growth period influences the expression level of Akt and ecdysone receptors in Bombyx. Further, the growth period and nutrition modulate the effect of exogenous hormones on Akt expression.

Impact of Health Educational Programme on Nutritional Status: A School Based Intervention Study among Adolescent Girls in an Urban Slum

BACKGROUND: Personal hygiene and correct dietary habits play a pivotal role in maintaining proper nutrition. Adolescent girls being future mother should be the target of health education programmes. Proper nutrition in this period of active growth will lead to a healthy adult and in turn healthy community. The study aimed to assess the effectiveness of a heath education programme regarding personal hygiene and dietary habits in improving nutritional status of the adolescent girl students. METHODS: A quasi-experimental study was conducted in two Government Bengali medium secondary schools located in a slum area under Kolkata Municipal Corporation. The study consisted of three steps. First a baseline survey was conducted to assess nutritional status of the students using WHO Z scores. This was followed by an intervention phase of 6 months during which weekly lecture and demonstration classes were taken in the study school. Second step was reassessment of nutritional status at post intervention. Third step was to follow them for another 6 months and reassess nutritional status to establish the effect of intervention. RESULTS: There was statistically significant decrement in proportion of undernourished students in study school from the pretest level to post-test level as compared to the control school and furthermore this improvement in nutrition was carried in follow up period. CONCLUSION: Sustained health education programme regarding correct hygiene and diet, with active involvement of parents and proper implementation of Government strategies can lead to better nutritional status and health of adolescents.

Parallel Seasonal Patterns of Photosynthesis, Fluorescence, and Reflectance Indices in Boreal Trees

Tree species in the boreal forest cycle between periods of active growth and dormancy alter their photosynthetic processes in response to changing environmental conditions. For deciduous species, these changes are readily visible, while evergreen species have subtler foliar changes during seasonal transitions. In this study, we used remotely sensed optical indices to observe seasonal changes in photosynthetic activity, or photosynthetic phenology, of six boreal tree species. We evaluated the normalized difference vegetation index (NDVI), the photochemical reflectance index (PRI), the chlorophyll/carotenoid index (CCI), and steady-state chlorophyll fluorescence (FS) as a measure of solar-induced fluorescence (SIF), and compared these optical metrics to gas exchange to determine their efficacy in detecting seasonal changes in plant photosynthetic activity. The NDVI and PRI exhibited complementary responses. The NDVI paralleled photosynthetic phenology in deciduous species, but not in evergreens. The PRI closely paralleled photosynthetic activity in evergreens, but less so in deciduous species. The CCI and FS tracked photosynthetic phenology in both deciduous and evergreen species. The seasonal patterns of optical metrics and photosynthetic activity revealed subtle differences across and within functional groups. With the CCI and fluorescence becoming available from satellite sensors, they offer new opportunities for assessing photosynthetic phenology, particularly for evergreen species, which have been difficult to assess with previous methods.

Starch Concentrations in Grapevine Leaves, Berries and Roots and the Effect of Canopy Management

Diurnal and seasonal starch changes in leaves, berries and roots of Vitis vinifera L. cv. Cabernet Sauvignon/99 Richter and the effect of canopy management (a combination of suckering, shoot positioning, and 33% defoliation) on these processes were investigated under field conditions. An increase in starch concentration of basal leaves occurred from the morning to the afternoon during the most active vegetative growth period (up to veraison), indicating a proportional change in storage or export of assimilates between day and night. During later developmental stages diurnal starch levels slightly declined or remained the same. Seasonally, leaf starch remained relatively stable until veraison, whereafter it increased, reaching highest concentrations at the post-harvest stage. Canopy management generally increased leaf starch concentrations. Berries contained no significant amounts of starch. Root starch concentrations were usually higher than those of leaves. Diurnally as well as seasonally, root starch accumulation patterns coincided with those of leaves, indicating a close relationship between source and sink tissue. Canopy management resulted in stable diurnal root starch concentrations without affecting the daily mean starch level; afternoon values of treated vines were, however, generally lower. The results imply that carbohydrate supply and starch-synthesising enzyme systems were not limited by manipulating the canopy and decreasing foliage. It seems, however, that particularly late in the season starch accumulation in roots may be delayed by canopy manipulation as applied. This indicates a shift in sucrose partitioning and its utilisation in roots and other sink areas, e.g. the berries, when the canopy is manipulated.

Biodegradable fixation systems in pediatric craniofacial surgery: 10-year experience with 324 patients

Over the past 15 years, resorbable materials have been successfully used for osteosynthesis, but their high cost prevents widespread application. However, the use of resorbable systems could be a method of choice, especially in treatment of children in the active growth period. Obviously, biodegradable materials not only are highly competitive with known metal constructs in terms of fixation rigidity, biocompatibility, and a low risk of infection but also have an undeniable advantage, such as gradual resorption allowing quick return of damaged bones to the physiological conditions of functioning. A special feature of bioresorbable systems is that they can be assembled using ultrasonic welding, which greatly facilitates the fixation process and also provides necessary rigidity, even in cases of joining very thin bones when reliable fixation with screws is impossible. Over the past 10 years, we have used biodegradable systems in 324 patients. In 244 of them, we used traditional (plate/screw) systems; in 80 cases, an ultrasonic welding system was chosen for osteosynthesis. In the present work, we discuss, based on clinical evidence, the advantages and disadvantages of both fixation systems for reconstructive craniofacial surgery in children.

Influence of Heliogeomagnetic Factors on the Thymus Gland Prenatal Formation

Currently there is no consensus about the etiology and pathogenesis of the conditions, manifested by a persistent increase in the thymus gland. A retrospective long-controlled study conducted on the basis of computer monitoring clinical examination of children discrete ages to test hypothesis about the sensitivity of the thymus gland during embryogenesis to heliogeomagnetic fluctuations (magnetic storms). The results showed that children with a persistent increase in the thymus and in healthy children during ontogeny (embryogenesis) geomagnetic conditions significantly different. It is assumed that the low level of geomagnetic activity during the final formation of all areas of the thymus (emigration of T-lymphocytes, check their peripheral lymphoid organs and in the period of active growth of the parenchyma of the thymus) may be a risk factor for persistent hyperplasia of thymus. The data obtained do not contradict the idea that developing structures required a certain optimum level cosmophysical impact.

PENGARUH INTERAKSI PACLOBUTRAZOL DAN TIPE TANAM JAJAR LEGOWO PADA PRODUKSI PADI METODE TANAM SRI

This study aims to find the effect of interaction of paclobutrazol and type Legowo Row Planting in paddy fields that use SRI cultivation method to increase rice yield, and can determine the best combination of effective and can be applied in paddy fields to increase production. The research was conducted in the Village of Sulu, Tatapaan Sub-district, South Minahasa Regency. This study uses a field experiment with split plot design in groups of two factors. As the first factor is the type of Legowo Row Planting 2: 1 and 4: 1. The second factor is the provision of paclobutrazol by spraying the plants with a dose of: 0 ppm and 600 ppm. Paclobutrazol will be given only once, that when plants in active vegetative growth period (about 30 days old plants after transplanting). Data analysis was used Two-Factor Interactions calculation. The interaction of two factors occured, if the effect of a factor changes when the change level of other factors change. The results indicated that the existence of interaction between treatment paclobutrazol and Legowo row that high interaction in the inhibition of the vegetative growth of rice crops varieties Serayu, middle interactions on the rate of plant growth, middle interactions in the treatment of paclobutrazol and Legowo row to increase the content of chlorophyll a and chlorophyll b in the leaves, the influence of high interaction of the number of productive tillers, high interaction on panicle length, high interaction to the increased weight of 1,000 grains, high interaction of the increase in the weight of dry unhusked rice per plot, and the lack of interaction to increase the number of grains per panicle. Paclobutrazol 600 ppm treatment gave a positive response on Legowo row 2: 1 for the inhibition of vegetative growth of crops to prevent crop is too high and not easily fall, increased chlorophyll a, increasing the weight of 1,000 grains and increased the weight of milled rice per plot. Paclobutrazol 600 ppm treatment gave a positive response on Legowo row 4: 1 to increase the pace of growth, increased chlorophyll b, an increase in the number of productive tiller and panicle length.

The influence of season on carbon allocation to suberin and other stem components of cork oak saplings.

The growth pattern of cork oak (Quercus suber L.), an important component of South Mediterranean woodlands, is seasonal. Seasonality has been found for shoot, radial and cork ring growth as well as for carbon (C) photoassimilation, nutrients remobilization and water relations, among other physiological aspects. However, little is known about the seasonality of C allocation to cork oak chemical compounds, including suberin, a major component of cork. In order to achieve this goal, an isotopic tracer experiment was conducted using 18-month-old cork oaks so that the fate of C photoassimilated in different seasons could be traced into biochemical (main organic) stem components. Two distinct patterns of C allocation, associated with the stages of active plant growth and dormancy, were identified and described. Evidence was provided that translocation of photoassimilated C to stems does not cease during the dormancy period and that suberin is the major C sink for the C assimilated throughout the whole active growth period, as compared with other stem components.

Effect of inhibitors of two isoprenoid biosynthetic pathways on physiological and biosynthetic characteristics of Dioscorea deltoidea cell suspension culture

The effect of phosmidomycin and mevinolin, which inhibit MEP and MVA isoprenoid biosynthetic pathways, respectively, on the growth (biomass accumulation, growth index, specific growth rate), physiological (respiration intensity and ratio between the cytochrome and cyanide-resistant respiration types), and biosynthetic (steroid glycoside biosynthesis) characteristics of the cell suspension culture of Dioscorea deltoidea Wall. has been studied. Both inhibitors decreased the growth index of a cell culture by 20–25%, but their influence on the cell growth dynamics was different. Mevinolin treatment reduced the maximum biomass accumulation by 20% as against the control but did not change the character of a growth curve. Phosmidomycin treatment caused a significant growth delay (a 6-day lag phase) followed by a short active growth period (μ = 0.29 days-1). Treatment of cells with inhibitors did not significantly influence on their total oxygen uptake rate, whose average value at different growth phases was equal to 100–200 mg О2/g of dry cell weight per hour, but cardinally changed characteristics of respiratory metabolism. The inhibitors increased the activity of a cyanide-resistant respiration and decreased the intensity of a cytochrome respiration; each inhibitor worked in its specific manner. In the case of mevinolin, the maximum level of cyanide-resistant respiration (70% of the total respiration intensity) was observed at initial growth phases; during the further cell culture growth, this value gradually reduced to 6–8%. Phosmidomycin treatment caused a reverse dynamics: at the initial growth phases, the contribution of cyanide-resistant respiration was 30%, whereas at the stationary and degradation phases it increased to 50–60%. The treatment of cells with phosmidomycin resulted in a double increase in the content of furostanol glycosides at the stationary growth phase, whereas the use of mevinolin-containing medium reduced the content of these compounds as against the control. Inhibitors also influenced on the ratio of individual glycosides, such as protodioscin, deltoside, and their 26-S-isomers. The obtained results confirm the hypothesis of a possible intermediate exchange between the plastid (MEP) and cytosolic (MVA) isoprenoid biosynthetic pathways; this exchange is directed mainly from the plastids to the cytosol.

The features of canine m. psoas minor histogenesis in the period of active growth during modeling the lumbar spine scoliosis

Objective. To identify the features of m. psoas minor histogenesis in growing dogs under conditions of the development of spinal scoliotic deformity. Material and Methods . Experiments were performed on 16 four-month-old mongrel dogs, males and females. In animals of Series I, the deformity was created by gangliotomy at five lumbar motion segments (L 2 -L 6 ), in animals of Series II - by fixation of adjacent L 3 -L 6 vertebral bodies with nickel titanium staples possessing thermochemical shape memory effect, and in animals of Series III - by implantation of titanium plates into the subchondral zone of vertebral growth plates, together with the staples. The control series included intact age-matched dogs. The X-ray examination of animals of Series I-III was performed in dorsoventral and lateral views at days 14, 30, 60, 90, and 180 after surgery. Paraffin and semi-thin sections of m. psoas minor from concave and convex sides of the lumbar scoliotic deformity zone were studied using light microscopy in 3 and 6 months after surgery. Results . Standard signs of degenerative-dystrophic changes and reparation by restitution/substitution type characterize the histogenesis of m. psoas mino r. The most marked destructive changes in the muscles on both sides of the deformity retained in the long-term only in animals of Series III. Conclusions . The study results can be used for evaluating the adaptation and plasticity potential of paravertebral muscles, as well as for developing models of the spine scoliotic deformity.

Oxygen Availability and Metabolic Dynamics During Mycobacterium tuberculosis Latency.

In vitro models of Mycobacterium tuberculosis (Mtb) nonreplicating persistence (NRP) suggest the rate of oxygen ( O2 ) depletion is a significant determinant in persistence. However, few studies have characterized the metabolic association between slow and rapid O2 depletion rates and successful versus failed persistence. We developed a theoretical model of Mtb metabolic adaptation that includes O2 driven genetic modulation of enzymes in the tricarboxylic acid cycle, energy, and redox recycling pathways. We conducted an in silico study of Mtb adaptation, and investigated the metabolic dynamics that enable persistence during slow versus rapid anaerobiosis. Consistent with in vitro studies, during rapid anaerobiosis the most significant enzymatic changes occurred during the active growth period while the majority of the slow anaerobic system's adaptive response occurred during the first phase of aerobic shiftdown (NRP1). The characteristic response of the two conditions differed, with the slow anaerobic system exhibiting positive adaptation response, upregulating six enzymes during NRP1, while the rapid system exhibited a negative adaptation response, decreasing the levels of seven enzymes during active growth. Results of our study illustrate the intricate metabolic balance Mtb achieves during adaptation to anaerobic conditions, and how failure in redox recycling correlates to failure in persistence. We have provided the first theoretical description of the genetic and metabolic death profile for Mtb during anaerobic growth. Insight into Mtbs dynamic adaptation response provides a unique systems framework for the development of targeted therapies to reduce the likelihood of mycobacterial persistence and the related incidence of latent tuberculosis infection.

Aspectos reprodutivos do rotífero Asplanchna do Brasil

Biological aspects of the brazilian retifer Asplanchna sp., reared in the laboratory, were studied and the mean curve of development and its connections with the generation time of amictic females were established. The mean generation time was around 22 hr; thus, the fust offspring of an amictic female were born, on the average, almost at the end of its active growth period. Studies on the longevity of amictic females and on the fecundity in amictic and mictic females were also carried out. The amictic females showed a mean longevity of 90.30 hr and a mean fecundity of 17 female offspring. On the other hand, an unfertilized female produced an average of 13 male offspring or, if fertilized, 4 resting-eggs.