Microscopic Approaches Research Articles

FF Activates Nucleation for Aggregation in Aqueous Medium: A Key Insight of Amyloid Plaque Formation

AbstractMolecular self‐association of monomers with multifaceted cross‐linkers, opens new possibilities for the development of various supramolecular‐networks that enable to participate in different functions. Plaques associated with senility that form in the brains of Alzheimer′s patients are mainly composed of beta amyloid (Aβ). It can be assumed that there must be a nucleation site which through reverse folding initiate to aggregate this Aβ plaque. It has been reported KLVFFA motif of Aβ sequence plays an important role as the amylogenic unit for Alzheimer disease. In order to identify the shortest sequence that would initiate the nucleation for such aggregation, we have synthesized N‐terminal protected two two‐residue peptides [Hex‐Phe(1)‐Phe(2)‐OMe: (FF)] and [Hex‐Phe(1)‐Ala(2)‐OMe: (FA)] an important fragment of KLVFFA motif. Using various microscopic and biophysical approaches, including measuring the hydrodynamic radii, it is observed that in fully aqueous condition in comparison to FA, FF nucleates higher degree of aggregates, along with substantial formation of dendrimeric amyloid fibrils, which has been elegantly visualized in Congo‐red assay through formation of distinct apple‐green birefringence. Such an observation leads to hypothesize that the ‘di‐phenylalanine’ unit (FF) plays a crucial role as the nucleation site towards attaining the aggregate for formation of the Aβ plaque through reverse folding.

Molecular survey and genetic diversity of Plasmodium sp. infesting domestic poultry in northeastern Thailand.

Haemosporidian parasites are prevalent worldwide and can cause economic losses in poultry production. These parasites are arousing interest in Thailand and are found in many avian species. There is insufficient information on the genetic diversity of these alveolates from the largest families - Plasmodidae, Haemoprotidae and Leucocytozoidae - specifically parasitising ducks, turkeys, and geese. Blood samples from 116 backyard poultry (60 ducks, 36 turkeys and 20 geese) in northeastern Thailand were investigated for Plasmodium spp., Haemoproteus spp. and Leucocytozoon spp. infections using microscopic examination and molecular approaches. A total of 37/116 birds (31.9%) had confirmed Plasmodium infections. The prevalence was 69.4% (25/36) in turkeys, 18.3% (11/60) in ducks, and 5.0% (1/20) in geese. Of these 37 positives, 86.5% were Plasmodium sp., 10.8% were P. gallinaceum and 2.7% were P. juxtanucleare. Sequence analysis based on the cytochrome b gene identified seven lineages, of which two were new lineages in backyard poultry. This is the first report on the prevalence of haemosporidian parasites in backyard poultry in northeastern Thailand. The results provide important data for better understanding the molecular epidemiology of haemosporidian parasites infection in poultry in this region, which will be helpful in controlling these blood parasites.

Endoscopic Versus Microscopic Transcanal Resection of Glomus Tympanicum: A Retrospective Comparative Study.

Comparison of outcomes of microscopic and endoscopic resection of glomus tympanicum (GT) tumors. Retrospective case review. Single tertiary referral center. All adult patients undergoing transcanal GT resection without mastoidectomy from 2007 to 2021. Surgical resection-endoscopic versus microscopic approach. Primary outcomes were tumor recurrence at 1 year and presence of residual tumor at conclusion of surgery. Secondary outcome measures included operative time, postoperative air-bone gap, postoperative symptom resolution, and surgical complications. Thirty-eight patients underwent resection of GT (74% female; mean age, 59 years). Twenty-nine cases were performed microscopically, and nine cases were performed endoscopically. Both endoscopic and microscopic approaches yielded high rates of complete tumor resection (27/29 microscopic cases, 7/9 endoscopic cases). There was no significant difference in mean operative time (2.3 hours for microscopic; 2.6 hours for endoscopic). On average, air-bone gaps (ABGs) decreased by 6.3 dB after endoscopic resection compared with 1.0 dB after microscopic resection ( p = 0.064). No patients were found to have tumor recurrence during an average follow-up interval of 21 months. These results suggest comparable outcomes with both endoscopic and microscopic approaches for GT resection, and decisions regarding preferred approach should be dictated by surgeon preference.

Understanding the Modulation of α-Synuclein Fibrillation by N-Acetyl Aspartate: A Brain Metabolite.

α-Synuclein (α-Syn) fibrillation is a prominent contributor to neuronal deterioration and plays a significant role in the advancement of Parkinson's Disease (PD). Considering this, the exploration of novel compounds that can inhibit or modulate the aggregation of α-Syn is a topic of significant research. This study, for the first time, elucidated the effect of N-acetyl aspartate (NAA), a brain osmolyte, on α-Syn aggregation using spectroscopic and microscopic approaches. Thioflavin T (ThT) assay revealed that a lower concentration of NAA inhibits α-Syn aggregation, whereas higher concentrations of NAA accelerate the aggregation. Further, this paradoxical effect of NAA was complemented by ANS, RLS, and the turbidity assay. The secondary structure transition was more pronounced at higher concentrations of NAA by circular dichroism, corroborating the fluorescence spectroscopic observations. Confocal microscopy also confirmed the paradoxical effect of NAA on α-Syn aggregation. Interaction studies including fluorescence quenching and molecular docking were employed to determine the binding affinity and critical residues involved in the α-Syn-NAA interaction. The explanation for this paradoxical nature of NAA could be a solvophobic effect. The results offer a profound understanding of the modulatory mechanism of α-Syn aggregation by NAA, thereby suggesting the potential role of NAA at lower concentrations in therapeutics against α-Syn aggregation-related disorders.

Developmental Changes in Genome Replication Progression in Pluripotent versus Differentiated Human Cells.

DNA replication is a fundamental process ensuring the maintenance of the genome each time cells divide. This is particularly relevant early in development when cells divide profusely, later giving rise to entire organs. Here, we analyze and compare the genome replication progression in human embryonic stem cells, induced pluripotent stem cells, and differentiated cells. Using single-cell microscopic approaches, we map the spatio-temporal genome replication as a function of chromatin marks/compaction level. Furthermore, we mapped the replication timing of subchromosomal tandem repeat regions and interspersed repeat sequence elements. Albeit the majority of these genomic repeats did not change their replication timing from pluripotent to differentiated cells, we found developmental changes in the replication timing of rDNA repeats. Comparing single-cell super-resolution microscopic data with data from genome-wide sequencing approaches showed comparable numbers of replicons and large overlap in origins numbers and genomic location among developmental states with a generally higher origin variability in pluripotent cells. Using ratiometric analysis of incorporated nucleotides normalized per replisome in single cells, we uncovered differences in fork speed throughout the S phase in pluripotent cells but not in somatic cells. Altogether, our data define similarities and differences on the replication program and characteristics in human cells at different developmental states.

Molecular characterization of Haemoproteus enucleator with emphasis on the host and geographic distribution

Haemoproteus species (Haemosporida, Haemoproteidae) are cosmopolitan and highly diverse blood parasites of birds that have been neglected in avian medicine. However, recent discoveries based on molecular diagnostic markers show that these pathogens often cause marked damage to various internal organs due to exo-erythrocytic development, sometimes resulting in severe and even lethal avian haemoproteosis, including cerebral pathologies. Molecular markers are essential for haemoproteosis diagnostics, but the data is limited, particularly for parasites transmitted in tropical ecosystems. This study combined microscopic and molecular approaches to characterize Haemoproteus enucleator morphologically and molecularly. Blood samples were collected from the African pygmy kingfisher Ispidina picta in Cameroon, and the parasite was identified using morphological characters of gametocytes. The analysis of partial cytochrome b sequences (cytb) identified a new Haemoproteus lineage (hISPIC03), which was linked to the morphospecies H. enucleator. Illustrations of blood stages were provided and the phylogenetic analysis showed that the new lineage clustered with five other closely related lineages belonging to the same morphospecies (hALCLEU01, hALCLEU02, hALCLEU03, hISPIC01, and hALCQUA01), with a maximum genetic distance between these lineages of 1.5 % (7 bp difference) in the 478 bp cytb sequences. DNA haplotype network was developed and identified geographic and host distribution of all lineages belonging to H. enucleator group. These lineages were almost exclusively detected in African kingfishers from Gabon, Cameroon, South Africa, and Botswana. This study developed the molecular characterization of H. enucleator and provides opportunities for diagnostics of this pathogen at all stages of its life cycle, which remains undescribed in all its closely related lineages.

Conspicuous chloroplast with light harvesting-photosystem I/II megacomplex in marine Prorocentrum cordatum.

Marine photosynthetic (micro)organisms drive multiple biogeochemical cycles and display a large diversity. Among them, the bloom-forming, free-living dinoflagellate Prorocentrum cordatum CCMP 1329 (formerly P. minimum) stands out with its distinct cell biological features. Here, we obtained insights into the structural properties of the chloroplast and the photosynthetic machinery of P. cordatum using microscopic and proteogenomic approaches. High-resolution FIB/SEM analysis revealed a single large chloroplast (∼40% of total cell volume) with a continuous barrel-like structure, completely lining the inner face of the cell envelope and enclosing a single reticular mitochondrium, the Golgi apparatus, as well as diverse storage inclusions. Enriched thylakoid membrane fractions of P. cordatum were comparatively analyzed with those of the well-studied model-species Arabidopsis (Arabidopsis thaliana) using 2D BN DIGE. Strikingly, P. cordatum possessed a large photosystem-light harvesting megacomplex (>1.5 MDa), which is dominated by photosystems I and II (PSI, PSII), chloroplast complex I, and chlorophyll a-b binding light harvesting complex proteins. This finding parallels the absence of grana in its chloroplast and distinguishes from the predominant separation of PSI and PSII complexes in A. thaliana, indicating a different mode of flux balancing. Except for the core elements of the ATP synthase and the cytb6f-complex, the composition of the other complexes (PSI, PSII, and pigment-binding proteins, PBPs) of P. cordatum differed markedly from those of A. thaliana. Furthermore, a high number of PBPs was detected, accounting for a large share of the total proteomic data (∼65%) and potentially providing P. cordatum with flexible adaptation to changing light regimes.

Navigating the Surgical Landscape: A Comprehensive Analysis of Endoscopic vs. Microscopic Transsphenoidal Pituitary Surgery Outcomes.

Pituitary surgery, a critical intervention for various pituitary disorders, has sparked ongoing debates regarding the preference between endoscopic and microscopic transsphenoidal approaches. This systematic review delves into the outcomes associated with these techniques, taking into account the recent advancements in neurosurgery. The minimally invasive nature of endoscopy, providing improved visualization and reduced morbidity, stands in contrast to the well-established track record of the conventional microscopic method. Examining outcomes for disorders such as Cushing's disease and acromegaly, the review synthesizes evidence from Denmark, Bulgaria, and China. Noteworthy advantages of endoscopy encompass higher resection rates, shorter surgery durations, and fewer complications, endorsing its effectiveness in pituitary surgery. While emphasizing the necessity for prospective trials, the review concludes that endoscopic approaches consistently showcase favorable outcomes, influencing the ongoing discourse on the optimal surgical strategies for pituitary disorders.

Unveiling the molecular interaction of hepatitis B virus inhibitor, entecavir with human serum albumin through computational, microscopic and spectroscopic approaches

Molecular docking, molecular dynamics (MD) simulation, atomic force microscopy (AFM) and multi-spectroscopic techniques were selected to unveil the molecular association between the hepatitis B virus (HBV) inhibitor, entecavir (ETR), and the major blood plasma transporter, human serum albumin (HSA). The entire docking and simulation analyses recognized ETR binding to subdomain IIA (Site I) of HSA through hydrogen bonds, hydrophobic and van der Waals forces while maintaining the complex’s stability throughout the 100 ns. A gradual lessening in the Stern-Volmer quenching constant ( K sv ) with rising temperatures registered ETR-induced quenching of HBV fluorescence as static quenching, thus advising complexation between ETR and HSA. The further advocation of this conclusion was seen from a larger value of the biomolecular quenching rate constant (( kq ) > 1010 M−1s−1), changes in the spectra (UV-Vis absorption) of HSA following ETR inclusion and ETR-induced swelling of HSA in the AFM results. The ETR appeared to bind to HSA with moderate affinity ( K a = 1.87 − 1.19 × 10 4 M−1) at 290, 300 and 310 K. Significant alterations in the protein’s secondary and tertiary structures, including changes in the protein’s Tyr/Trp microenvironment, were also detected by circular dichroism and three-dimensional fluorescence spectra when the protein was bound to ETR. The findings of the drug displacement study backed the docking results of Site I as ETR's preferred binding site in HSA. Communicated by Ramaswamy H. Sarma

Dynamic Heat Transfer Simulation in Textile for Practical Application: A Comparative Analysis of Microscopic and Macroscopic Approaches

Heat transfer simulation in textile materials has many practical applications, such as in the design of protective clothing for firefighters, the development of thermal insulation materials, and the optimization of temperature control in textiles for comfort and performance. This paper presents a study on heat transfer simulation in woven fabrics using the Comsol Multiphysics® application. The simulations were carried out for both microscopic (3D) and macroscopic (1D) scales and the heat flux variation was compared with experimental results. The steady-state average heat flow through the textile was determined, and this value was used to calculate the thermal resistance of the woven fabrics. The thermal resistance values obtained were within a deviation range of 4.2% to 6.3% from the values determined according to ISO 11092/1016, thus validating the proposed model. For the transient regime, the microscopic approach proved to be more accurate, the estimated time for the heat flow to reach a certain value depending essentially on the scale approached in the modeling. This finding has particular significance in the field of protective clothing, especially for firefighters exposed to radiant heat sources, where estimating the time for burns to occur is crucial.

Acoustic shock wave-induced ordered to disordered switchable phase transitions: A case study of ferroelectric triglycine sulphate single crystal for the application of molecular switches

Highly efficient switchable materials for external stimuli have impressive applications in the development of precious sensor devices. However, most of the materials do not possess effective switchable structural features such that finding potential switchable materials is one of the critical research tasks for materials science researchers. In the present research perspective, we demonstrate successive switchable phase transitions occurring between the order to disorder states in the ferroelectric triglycine sulphate (TGS) single crystal along the (011) plane with respect to the number of shock pulses (0,1 and 2 counts) and the observed results are evaluated by the diffraction, spectroscopic, microscopic and thermal approaches. The observed switchable phase transitions occur due to the shock wave-induced inter-conversion of planar configuration to the non-planar configuration of Glycine molecules, particularly GII and GIII. The ratio of the normalized Raman bands Sym-CH2/Asym-CH2 is found to be 2.0 and 2.5 for the respective order to disorder states such that these values are identified to be well-matched with the literature reports. In addition to that, the SEM images authenticate that, during the amorphous to crystalline phase transitions, the appearance of well-defined (011) plane on the surface is ensured due to the dynamic recrystallization. To the best of our knowledge, to date, it is probably the first report for the phase switching of order to disorder states of TGS sample by the impact of acoustical shock waves and because of its efficient switchability, it can be strongly suggested for the application of molecular switches.

A single coelomic cell type is involved in both immune and respiratory functions of the coastal bioindicator annelid: Capitella C-Channel1 from the English Channel

The polychaete Capitella is a typical member of the ‘thiobiome’, and is commonly used as an eutrophication indicator species in environmental assessment studies. To deal with a sulfide-rich and poisonous surrounding, cells in close contact with the environment, and thus able to play a major role in detoxication and survival, are circulating cells. This work aimed to morpho-functionally describe the circulating coelomic cells of Capitella from the English Channel inhabiting the sulfide-rich mud in Roscoff Harbor. In general, worms have three types of circulating cells, granulocytes involved in bacterial clearance and defense against microorganisms, eleocytes with an essentially trophic role and elimination of cellular waste, and erythrocytes which play a role in detoxification and respiration via their intracellular hemoglobin. By combining diverse microscopic and cellular approaches, we provide evidence that Capitella does not possess granulocytes and eleocytes, but rather a single abundant rounded cell type with the morphological characteristics of erythrocytes i.e. small size and production of intracellular hemoglobin. Surprisingly, our data show that in addition to their respiratory function, these red cells could exert phagocytic activities, and produce an antimicrobial peptide. This latter immune role is usually supported by granulocytes. Our data highlight that the erythrocytes of Capitella from the English Channel differ in morphology and bear more functions than the erythrocytes of other annelids. The simplicity of this multi-task (or polyvalent) single-cell type makes Capitella an interesting model for studies of the impact of the environment on the immunity of this bioindicator species.

Cryptosporidium species diagnosis in handlers of domestic pigeons in Baghdad City: Molecular and microscopic approaches.

The aim of this study is to detect the prevalence and diagnosis of molecular characteristics of Cryptosporidium infection in handlers of domestic pigeons in Baghdad City. Traditional and molecular diagnostic methods were employed to detect and identify Cryptosporidium species. Sixty stool samples were collected from the handlers of domestic pigeons, and various techniques, including direct smear, flotation concentration, staining methods, and DNA extraction coupled with nested polymerase chain reaction (PCR), were utilized. The results obtained from traditional methods indicated an overall infection rate of 55% in handlers of domestic pigeons, while significant variations were noted between male and female handlers. Age group 21-40 years were found to have higher infection rates were found to have higher infection rates. The prevalence of Cryptosporidium also displayed temporal variability throughout the study period. Molecular analysis using nested PCR revealed higher infection rates of 86% in handlers of domestic pigeon samples. Genotyping and phylogenetic analysis identified the presence of Cryptosporidium parvam species in handlers of domestic pigeons, indicating zoonotic transmission potential. These findings underscore the high prevalence of Cryptosporidium infection among handlers of domestic pigeons in Baghdad City.

In vivo monitoring of leukemia-niche interactions in a zebrafish xenograft model.

Acute lymphoblastic leukemia (ALL) is the most common type of malignancy in children. ALL prognosis after initial diagnosis is generally good; however, patients suffering from relapse have a poor outcome. The tumor microenvironment is recognized as an important contributor to relapse, yet the cell-cell interactions involved are complex and difficult to study in traditional experimental models. In the present study, we established an innovative larval zebrafish xenotransplantation model, that allows the analysis of leukemic cells (LCs) within an orthotopic niche using time-lapse microscopic and flow cytometric approaches. LCs homed, engrafted and proliferated within the hematopoietic niche at the time of transplant, the caudal hematopoietic tissue (CHT). A specific dissemination pattern of LCs within the CHT was recorded, as they extravasated over time and formed clusters close to the dorsal aorta. Interactions of LCs with macrophages and endothelial cells could be quantitatively characterized. This zebrafish model will allow the quantitative analysis of LCs in a functional and complex microenvironment, to study mechanisms of niche mediated leukemogenesis, leukemia maintenance and relapse development.

An empirical formula of nuclear <i>β</i>-decay half-lives

Nuclear <i>β</i>-decay half-lives play an important role not only in nuclear physics, but also in astrophysics. The <i>β</i>-decay half-lives of many nuclei involved in the astrophysical rapid neutron-capture (r -process) still cannot be measured experimentally, so the theoretical predictions of nuclear <i>β</i>-decay half-lives are inevitable for r-process studies. Theoretical models for studying the nuclear <i>β</i>-decay half-lives include the empirical formula, the gross theory, the quasiparticle random phase approximation (QRPA), and the shell model. Compared with other theoretical models of <i>β</i>-decay half-lives, the empirical formula has high computational efficiency, and its prediction accuracy can be improved by introducing more and more physical information. In this work, an empirical formula without free parameters is proposed to calculate the nuclear <i>β</i>-decay half-lives based on the Fermi theory of <i>β</i> decay. By including the pairing effect, the shell effect, and the isospin dependence, the newly proposed empirical formula significantly improves the accuracy of predicting the nuclear <i>β</i>-decay half-life. For the nuclei with half-lives less than 1 second, the root-mean-square deviation of the common logarithms of the nuclear <i>β</i>-decay half-life predicted by the new empirical formula from the experimental data decreases to 0.220, which is improved by about 54% compared with that by the empirical formula without free parameters, even better than those by other existing empirical formulas and microscopic QRPA approaches. In the unknown region, the nuclear <i>β</i>-decay half-lives predicted by the new empirical formula are generally shorter than those predicted by the microscopic models in the light nuclear region, while those predicted by the new empirical formula in the heavy nuclear region are generally in agreement with those predicted by the microscopic models. The half-lives of neutron-rich nuclei on the nuclear chart are then predicted by the new empirical formula, providing nuclear <i>β</i>-decay half-life inputs for the r-process simulations.

Transient Tire Slip Losses Using the Brush Theory

ABSTRACT Tire slip losses have been shown to have a significant impact on vehicle performance in terms of energy efficiency, thus requiring accurate studies. In this paper, the transient dissipation mechanisms connected to the presence of micro-sliding phenomena occurring at the tire–road interface are investigated analytically. The influence of a two-dimensional velocity field inside the contact patch is also considered in light of the new brush theory recently developed by the authors. Theoretical results align with findings already known from literature but suggest that the camber and turn spins contribute differently to the slip losses and should be regarded as separate entities when the camber angle is sufficiently large. The present work shows that an additional amount of power which relates to the initial sliding conditions is generated or lost during the unsteady-state maneuvers. A simple example is presented to illustrate the discrepancy between the microscopic and macroscopic approaches during a transient maneuver.

Morphological and transcriptional analysis of Colletotrichum lindemuthianum race 7 during early stages of infection in common bean.

The infection process of the hemibiotrophic fungus Colletotrichum lindemuthianum has been independently studied at the microscopic and genomic levels. However, the relationship between the morphological changes and the pathogenicity mechanisms of the fungus at the early stages of the infection remains uncharacterized. Therefore, this study attempts to bridge this gap by integrating microscopic and transcriptional approaches to understand the infection process of C. lindemuthianum. Fungal structures were followed by fluorescence microscopy for 120 hours. Simultaneously, the transcriptomic profile was made using RNAseq. Morphological characterization shows that appressoria, infective vesicles, and secondary hypha formation occur before 72 hours. Additionally, we assembled 38,206 transcripts with lengths between 201 and 3,548 bp. The secretome annotation revealed the expression of 1,204 CAZymes, of which 17 exhibited secretion domains and were identified as chitinases and β-1,3-glucanases, 27 were effector candidates, and 30 were transport proteins mostly associated with ABC-type. Finally, we confirmed the presence and expression of CAC1 role during the appressoria formation of Clr7. This result represents the first report of adenylate cyclase expression evaluated under three different approaches. In conclusion, C. lindemuthianum colonizes the host through different infection structures complemented with the expression of multiple enzymes, where CAC1 favors disease development.

Amantadine's Neuroprotective Effects in Rabbit Spinal Cord Ischemia/Reperfusion Model.

To examine the effects of amantadine, a drug with neuroprotective and anti-inflammatory activities on oxidative stress, tissue necrosis, apoptosis, and neurological recovery in an experimental rabbit spinal cord ischemia-reperfusion injury (SCIRI) model. A total of 32 rabbits were randomized into five groups: control, ischemia, vehicle, methylprednisolone (MP), and amantadine (AMT) (n=8/each). At 24th-hour neurological examination was performed, spinal cord tissues were collected, and biochemical and histopathological examinations were performed. When ischemia and vehicle groups were compared with control group, significant increase was seen in serum and tissue caspase-3, malondialdehyde (MDA), and myeloperoxidase (MPO) levels (p < 0.001); significant decrease was seen in serum and tissue catalase (CAT) levels (p < 0.001); and significant increase was seen in serum xanthine oxidase (XO) levels (p < 0.001). When the ischemia group and the MP and AMT groups were compared, low serum and tissue caspase-3 levels (p < 0.001), high serum and tissue CAT levels (p < 0.001), significantly low serum XO levels (p < 0.001), low serum and tissue MDA levels (p < 0.05) and tissue MPO levels (p < 0.001) were found. Both AMT and MP groups showed decreased histopathological score and higher number of normal neurons (p < 0.001) compared to ischemia group. Both AMT and MP showed better modified Tarlov scores compared to the ischemia group (p < 0.001). Our study found that AMT had antioxidant, anti-inflammatory, anti-apoptotic, and neuroprotective effects on SCIRI. We used biochemical, microscopic, and ultrastructural approaches to demonstrate these effects. AMT might be a candidate medication for SCIRI prophylaxis and treatment.

Role of Rhipicephalus bursa larvae in transstadial transmission and endemicity of Babesia ovis in chronically infected sheep.

Babesia ovis, transmitted by Rhipicephalus bursa ticks, is the causative agent of ovine babesiosis, a disease characterized by fever, anemia, hemoglobinuria, and high mortality in sheep. This study investigates whether sheep that survived babesiosis without treatment can serve as a source of infection for B. ovis-free host-seeking R. bursa larvae in a later season. Three donor sheep were experimentally infected with B. ovis, and after six months, persistence of B. ovis was assessed through blood and tick transmission experiments. Blood from donor sheep was intravenously injected into three recipient sheep, while donor sheep were also infested with B. ovis-free R. bursa larvae. Engorged nymphs molted to adults, and new recipient sheep were infested with these ticks. All recipient sheep were monitored for B. ovis for 100 days using microscopic, serological, and molecular approaches. The presence of B. ovis was confirmed in the recipient sheep that received blood, leading to clinical infection in two. However, no B. ovis was detected in recipient sheep infested with ticks. These results suggest that sheep recovering from B. ovis infection do not serve as a source of infection for R. bursa larvae in subsequent seasons.

Ecosystem Energy Changes

In this paper energy in ecosystem was studied. Energy balance equations of ecosystem were derived. Most of the energy in the Earth’s system comes from just a few sources: solar energy, gravity, radioactive decay, and the rotation of the earth. Earth is constantly changing as energy flows through the system. Earth’s weather and climate are mostly driven by energy from the Sun. The Sun provides the energy that drives the water cycle on Earth. In this paper different forms of energy, specific types, using and energy conservation were studied. Environments are highly complex systems whose evolution is determined by complicated networks of positive and negative feedback loops. In this paper macroscopic and microscopic approaches to energy flow through the ecosystem have been used.